This invention produces torsion beam applied to metal fatigue is suppressed in torsion beam suspension apparatus for an automobile, to a torsion beam manufacturing method and torsion beam manufacturing apparatus.
　This application claims the Japanese Patent Application No. 2017-194394, filed on October 4, 2017, priority based on the Japanese Patent Application No. 2018-056868, filed in Japanese on March 23, 2018 and, incorporated these contents here.
BACKGROUND
[0002]
　As is well known, torsion beam suspension apparatus have been widely used as a form of automotive suspension systems.
　The torsion beam suspension apparatus: is connected a pair of left and right trailing arms for rotatably supporting the left and right wheels by the torsion beam further comprises a torsion beam assembly pair of left and right spring receiving portions are joined to the left and right ends near the torsion beam; torsion beam and a spring and absorber for connecting the vehicle body; comprising a. Torsion beam via a pivot shaft extending from the left and right of the vehicle body toward the center side, are swingably connected to the vehicle body.
[0003]
　Torsion beam, for example, is formed by plastic working a metal pipe by press molding and hydro forming, cross section perpendicular to the longitudinal direction of the torsion beam is formed on the closed section of the substantially V-shaped or substantially U-shaped and are (for example, see Patent Document 1).
[0004]
　Torsion beam has a constant shape closed cross-section portion having a substantially constant closed cross-section of substantially V-shaped or substantially U-shaped, and a mounting portion connected to the left and right trailing arms, located between the fixed shape closed-section portion and the mounting portion and a shape-changing portion (gradually changing portion) which, when the vehicle body is subjected to an external force from the road surface so as to ensure the roll stiffness of the vehicle body by torsional rigidity mainly torsion beam.
[0005]
　On the other hand, even torsion beam had sufficient roll stiffness, torsion beam, for receiving a variety of external force from the road surface through the wheels and trailing arm, complex stress distribution due to such external force is generated and, metal fatigue is likely to progress. The metal fatigue, for example, significantly likely to occur at the connection portion near between shape-changing portion and a constant shape closed-section portion.
[0006]
　Therefore, even when subjected to various external forces from the road surface, it is necessary to suppress the development of metal fatigue, these various techniques for suppressing metal fatigue has been developed (e.g., Patent Documents 2-6 reference).
[0007]
　The technique described in Patent Document 2, after press forming torsion beam, quenching, tempering, performing shot peening, by curing the outer surface of the torsion beam, thereby improving the fatigue characteristics of the torsion beam.
[0008]
　The technique described in Patent Document 3, by using a steel pipe surface hardness is high after the heat treatment, to improve the surface hardness of the torsion beam, thereby improving the fatigue characteristics of the torsion beam.
[0009]
　The technique described in Patent Document 4 imparts that a tensile stress applying pressure toward the outside from the inside of the steel pipe by hydroforming, as a result, to improve the fatigue properties by reducing the residual stress of the torsion beam there.
[0010]
　The technique described in Patent Document 5 has a high residual stress sites be to out-of-plane deformation, to improve fatigue characteristics by reducing the tensile residual stress. As means for out-of-plane deformation, hydroforming is used.
[0011]
　The technique described in Patent Document 6, a tensile force along the longitudinal direction applied to the torsion beam material, thereby, thereby improving the fatigue characteristics by reducing the residual stress of the torsion beam.
CITATION
Patent Document
[0012]
Patent Document 1: Japanese Patent 2011-635 JP
Patent Document 2: Japanese Patent 2001-123227 JP
Patent Document 3: Japanese Patent 2008-063656 JP
Patent Document 4: Japanese Patent 2013-091433 JP
Patent Document 5: WO 2017/155056
Patent Document 6: WO 2017/169733
Summary of the Invention
Problems that the Invention is to Solve
[0013]
　However, to improve the fatigue properties of the torsion beam by applying the technique described in Patent Document 2 to 5, on which not necessarily easy, there is a problem of initial costs and production running costs such as equipment investment increases . In particular, hydroforming described in Patent Document 5, this problem is remarkable.
　According to the technique described in Patent Document 6, it is possible to solve these problems. However, in order to reduce the granted to residual stress tensile as calculated, labor for firmly securing the holding of the product at both ends it was essential. Therefore, further improvement in productivity has been demanded omitted this time.
　Thus, the torsion beam manufacturing technology has been desired that is capable of producing torsion beam fatigue characteristics excellent more efficiently.
[0014]
　The present invention has been made in view of such circumstances, that is capable of producing excellent torsion beam fatigue properties more efficiently, and to provide the torsion beam manufacturing method and torsion beam manufacturing apparatus.
Means for Solving the Problems
[0015]
　In order to solve the above problems, the present invention proposes the following means.
(1) torsion beam manufacturing method according to an embodiment of the present invention includes a central portion which is closed cross-section of substantially V-shaped or substantially U-shaped in cross section perpendicular to the longitudinal direction an arbitrary position of the longitudinal direction, said central portion a method for continuous in and the closed cross-section to produce a torsion beam having a shape changing portion having a connection region having a closed cross section of different shapes, the torsion beam material the central portion and the shape change portion is formed at least the connection region of the hand, said to thickening of at least the connection region for applying a compression force in the longitudinal direction, it has a compression step of obtaining the torsion beam.
　According to the torsion beam manufacturing method according to this embodiment, to apply a compressive force to at least the connection region during the compression process, it is possible to perform the reduction or elimination of residual to have residual stresses, and reinforcement by thickened simultaneously.
　As a result, it is possible to produce an excellent torsion beam fatigue properties. Moreover, on that it does not require post-heat treatment, since the device structure and manufacturing process who apply an axial compression as compared with the case of applying an axial tensile is simplified, can be efficiently produced.
[0016]
(2) In the torsion beam method according to the above (1), and wherein the compression step, the inside of the outer part along the longitudinal direction than the connection region is supported by the inner support member, the outer portion of the outer while pinched by the outer clamping member and moving the inner support member and the outer clamping member in a direction toward the central portion, it may be added to the compressive force.
　In this case, in the compression process, in terms of supporting the inside of the outer portions of the torsion beam material in the inner support member, since applying a compressive force to the outer side of the outer portion is clamped by the outer clamping member, the Dosotokata portion it can be given easily compressive force while suppressing out-of-plane deformation.
[0017]
(3) In the torsion beam manufacturing method described in the above (2), wherein the compression step, the connection outside the region supported by the outer support member, the inner support member and said moving and and synchronization in the same direction of the outer clamping member and it may move the outer support member.
　In this case, the outer support member, to move in synchronism with the movement of the inner support member and the outer clamping member does not inhibit deformation along the longitudinal direction of the torsion beam material accompanying the compression. Therefore, it is possible to impart surely compressive force to the torsion beam material, it is possible to reduce or remove reliably residual stress.
[0018]
(4) In the torsion beam method according to the above (1), in the compression step, the torsion beam material and across it to relatively approach each other along the longitudinal, length of the torsion beam material the compressive force it may be added over.
　In this case, to compress longitudinally inward torsion beam material over its entire length, the residual stress without leakage can be reduced or removed.
[0019]
(5) In the torsion beam manufacturing method according to any one of the above (1) to (4), in said compression step, the longitudinal direction of 0.5% or more for at least the connection region of the torsion beam blank 2 the distortion amount of 2.0% or less may be applied.
　In this case, a sufficient compressive force to to remove or reduce the residual stress of the torsion beam materials, can be imparted without causing buckling (buckling).
[0020]
(6) In the torsion beam manufacturing method according to any one of the above (1) to (5), prior to the compression step may include a pressing step of the blank tube is pressed to obtain the torsion beam material .
　In this case, at the time after the pressing step, there remains a residual stress in the torsion beam material can be followed by the compression step, to remove or reduce this.
[0021]
(7) In the torsion beam method according to the above (1), prior to the compression step, further have a preparation step of preparing the torsion beam material with warp along the longitudinal direction at least in the longitudinal direction of the part and, in the compression process, while restricting the elongation between both end edges of the torsion beam material, the pressure to reduce the warpage may be given to the torsion beam material.
　In this case, it is possible to impart a compressive force to the torsion beam material with a simpler device configuration.
[0022]
In the torsion beam manufacturing method according to (8) above (7), in the preparation step, it may be prepared the torsion beam material said end edge is inclined relative to the longitudinal direction.
　In this case, the inclination direction and inclination angle of the end edges, it is possible to change the compression ratio in each part of the cross section crossing the longitudinal direction of the torsion beam material.
[0023]
(9) In the torsion beam manufacturing method described in the above (7) or (8), in said compression step, said torsion beam material at least the connecting region said longitudinal or less 2.0% 0.5% or more to the the amount of distortion may be applied.
　In this case, a sufficient compressive force to to remove or reduce the residual stress of the torsion beam materials, can be imparted without causing buckling (buckling).
[0024]
(10) In the torsion beam manufacturing method according to any one of the above (1) to (9), when applying the compressive force in the compression step may support at least the outer surface of the connection region.
　In this case, the compression process, since applying a compressive force while supporting the outer surface of at least the connection area, the machining target is also a thin torsion beam material thickness, it is possible to prevent the buckling of the (buckling).
[0025]
(11) torsion beam manufacturing apparatus according to an embodiment of the present invention includes a central portion in cross section perpendicular to the longitudinal direction is a closed cross-section of substantially V-shaped or substantially U-shaped at any position in the longitudinal direction, said central portion an apparatus for manufacturing a torsion beam having a shape changing part, the having a connection area and having a closed cross section of a different shape as the closed section continuous to, torsion beam material the central portion and the shape change portion is formed of the portion of the on one side than the connection area when viewed along the longitudinal direction of the torsion beam material, a pair of holding mechanisms for holding the part on the other side of the connection region; each first drive mechanism that relatively close between the holding mechanism and; comprises.
　According to the torsion beam manufacturing apparatus according to this embodiment, the pair of holding mechanism and the first driving mechanism, by applying a compressive force in the longitudinal direction to at least the connection region of the torsion beam material remaining in the torsion beam material it is possible to perform the reduction or elimination of have residual stresses, and reinforcement by thickened simultaneously.
　As a result, it is possible to produce an excellent torsion beam fatigue properties. Moreover, since it does not require post-heat treatment, it is possible to efficiently manufacture.
[0026]
(12) In the torsion beam manufacturing apparatus according to (11), wherein the holding mechanism may hold both ends of the torsion beam material.
　In this case, to compress and hold the ends of the torsion beam material by the pair of holding mechanisms can impart a compressive force over the entire length of the torsion beam material. Therefore, it is possible to reduce or remove residual stress without omission over the entire length of the torsion beam material.
[0027]
(13) In the torsion beam manufacturing apparatus according to the above (12), said central portion and said shape changing unit movable die having a corresponding shape to the; prior to applying said central portion and said shape changing portion to said torsion beam material to the base pipe, and a second drive mechanism for pressing the movable mold; it may further comprise a.
　In this case, by pressing the movable mold base tube by a second driving mechanism, it is possible to obtain a torsion beam material having a central portion and a shape changing part.
[0028]
In the torsion beam manufacturing apparatus according to (14) above (11), at least one of the respective retaining mechanism, wherein the inner support member to be inserted inside the shape change unit; sandwiching outside of the shape-changing portion an outer clamping member; may comprise.
　In this case, in terms of supporting the inside of the shape changing portion of the torsion beam material in the inner support member, since the outer shape change unit can be a compressive force and clamped by outer clamping member, out-of-plane deformation of the shape-changing portion it can be given easily compressive force while suppressing a.
[0029]
(15) In the torsion beam manufacturing apparatus according to the above (14), said central portion and said shape changing unit movable die having a corresponding shape to the; prior to applying said central portion and said shape changing portion to said torsion beam material to the base pipe, and a second drive mechanism for pressing the movable mold; it may further comprise a.
　In this case, by pressing the movable mold base tube by a second driving mechanism, it is possible to obtain a torsion beam material having a central portion and a shape changing part.
[0030]
(16) In the torsion beam manufacturing apparatus according to the above (15), may be employed the following configuration: the movable mold, and the movable mold body having a shape corresponding to at least the central portion, at least the has a shape corresponding to the shape changing portion and a movable mold end portion provided so as to move freely with respect to the movable mold body portion, the movable mold ends to the movable mold body portion and a third drive mechanism for moving; said movable mold end also serves as the outer clamping member.
　In this case, with respect to base tube which is pressed by the movable die, at least with providing a shape corresponding to the central portion, giving a shape corresponding to at least the shape changing part by the movable mold ends by movable mold body portion. Thus by inserting the inner support member to the inside of the shape changing portion of the torsion beam material obtained, also an outer shape change portion while sandwiched by the movable mold ends, apply a compressive force to the torsion beam material. According to this configuration, since the movable mold end also serves as the outer clamping member, without transferring the torsion beam material raw tube and the obtained by pressing to another device, along a longitudinal direction as it is continuously compressive force can be added.
[0031]
(17) (11) in the torsion beam manufacturing apparatus according to any one of - (16) may be employed the following configuration: further comprising a support die for supporting the torsion beam material; the supporting metal types, the torsion beam material, supporting a support die body portion for supporting the portion including the central portion, and provided movably with respect to the support mold body portion, at least the shape-changing portion support comprising a mold end portion.
　In this case, when applying a compressive force to the torsion beam material, since the supporting mold end is movable relative to the support die main body, does not inhibit deformation of the torsion beam material due to compression in the longitudinal direction. Therefore, it is possible to impart surely compressive force to the torsion beam material, it is possible to reduce or remove reliably residual stress.
[0032]
(18) (11) in the torsion beam manufacturing apparatus according to any one of - (17), may be employed the following configuration: further comprising a control unit for controlling said first driving mechanism; the control unit, the first by operating the driving mechanism to impart strain of 2.0% or less than 0.5% in the longitudinal direction at least with respect to the connection region of the torsion beam material.
　In this case, a sufficient compressive force to to remove or reduce the residual stress of the torsion beam materials, can be imparted without causing buckling (buckling).
[0033]
(19) In the torsion beam manufacturing apparatus according to any one of the above (11) to (18), of the torsion beam material held by the pair of holding mechanisms, the support for supporting at least the outer surface of the connection region parts may further comprise a.
　In this case, when applying the compressive force in the longitudinal direction to at least the connection region of the torsion beam material, since applying a compressive force while supported by the support portion outer surface of at least the connection area, the processing object is a plate thickness thin even torsion beam material, it is possible to prevent the buckling.
[0034]
(20) torsion beam manufacturing apparatus according to another aspect of the present invention includes a central portion which is closed cross-section of substantially V-shaped or substantially U-shaped at any position of the cross section perpendicular to the longitudinal direction a longitudinal direction, said central an apparatus for manufacturing a torsion beam having a shape changing part, the having a connection region which continues to the part and having a closed cross section of a different shape as the closed section, cutlet comprises the central portion and the radius variations a first mold having a recess at least said longitudinal part accepts torsion beam material with warp along the longitudinal direction, in a direction to reduce the warpage relative arranged the torsion beam material in said recess includes a second mold approaching along a fourth drive mechanism that relatively close between said first die and said second die, wherein the recess, said torsion beam A pair of stretch restricting surface facing the opposite edges of the timber, the distance between the pair of stretch regulating surface is shorter than the total length along the warp of the torsion beam material.
　According to the torsion beam manufacturing apparatus according to this embodiment, place a torsion beam material to a first mold in the recess, and, to close the second mold into the second mold by the driving force of the fourth drive mechanism. The torsion beam material is reduced warpage is pressurized from the second mold, whereby, since the elongation between both end edges are regulated by a pair of stretch regulating surfaces for at least the shape changing portion of the torsion beam material longitudinal compression force is applied. This compressive force, it is possible to perform the reduction or elimination of residual stress remaining in the torsion beam material, and a reinforcement by thickened simultaneously. As a result, it is possible to produce an excellent torsion beam fatigue properties. Moreover, without the need for post-heat treatment, it is possible to efficiently produce a simple device configuration.
[0035]
　The present invention may employ the following aspects in addition to the above aspects.
(A) Another aspect of the present invention, a pair of left and right arms used torsion beam suspension apparatus is connected to both ends in the longitudinal direction, the longitudinal direction perpendicular to the cross section of the front and rear ends in the longitudinal direction of the vehicle body torsion beam while having a shape changing unit which is located between the central portion and the mounting closed cross-section portion of the substantially V-shaped or substantially U-shaped projecting upper or lower side to the central portion and the mounting closed-section portion a torsion beam method of manufacturing and a pressing step of forming the torsion beam material having said shape changing part and the central portion of the metal material tube is pressed, the shape change at least the central portion of the torsion beam material comprising a connection part for connecting the parts and compression step of compressing the longitudinal direction.
[0036]
　According to the torsion beam manufacturing method according to this embodiment, connected to a pressing step of forming the torsion beam material having a central portion and a shape changing portion of the metal material tube is pressed, at least the central portion and the shape changing portion of the torsion beam material a connection portion that is provided with the compression processing step of compressing in the longitudinal direction, it is possible to reduce or remove the residual tensile stress from the connecting portion.
　As a result, it is possible to produce a torsion beam that has fatigue properties superior efficiently.
[0037]
　In this specification, the central portion, a substantially constant closed cross section of the substantially V-shaped or substantially U-shaped (e.g., valleys of the wall portion constituting the concave side of the substantially V-shaped or substantially U-shaped (bottom )) refers to the moiety that is formed continuously along the longitudinal direction. Note that up to the shape changing portion valleys of the wall portion constituting the concave side of the substantially V-shaped or substantially U-shaped (bottom) is gradually shallower continuously, be partially irregularities are formed It is included in the center.
[0038]
　Further, in the central portion, toward the center from the left and right ends along the longitudinal direction of the torsion beam, while maintaining a substantially V-shaped or substantially U-shaped, be configured such that the area of ​​the closed cross section gradually changes good. Such a shape of the torsion beam or torsion beam material, toward the center from the left and right ends in the longitudinal direction, obtained by a press working of a metal material tube whose diameter gradually changes.
[0039]
　The portion in this specification, the shape changing part, which forms the trough portion of the wall portion constituting the concave side of the substantially V-shaped or substantially U-shaped (bottom) is gradually shallow is formed continuously you say. Incidentally, in the middle of the shape-changing portion valley (bottom) may be formed partially shallow become part.
[0040]
　Further, in this specification, the mounting closed cross-section portion, is positioned longitudinally outward of the shape-changing portion (the vehicle width direction outer side), the recess having a substantially V-shaped or substantially U-shaped is formed say no part.
[0041]
　Further, in this specification, the connecting portion connecting the central portion and the radius variations, refers to the portion including the boundary between the center and the radius variations, substantially V-formed along the longitudinal direction in the central portion valleys of the wall portion constituting the concave shape or a substantially U-shaped (bottom) is a portion containing the site to migrate to gradually shallow will form inclined relative to the longitudinal direction continuously in the shape changing part. The range of the connecting portion can be arbitrarily set based on the distribution and the like of the tensile residual stress.
[0042]
(B) a torsion beam method according to the (a), the in the compression processing step, the torsion beam radius variations of the shape changing portion is inserted the inner support member inwardly of the shape change of the material and held by the support member to compress said connecting portion in the longitudinal direction.
[0043]
　According to the torsion beam manufacturing method, in the compression process, by holding the shape-changing portion supporting member shape changing portion is inserted the inner support member inwardly of the shape change of the torsion beam material, the longitudinal connecting portions since compression, it is possible to reliably suppress the deformation of the shape-changing portion while compressing easily longitudinally inward connecting portions of the torsion beam material.
　As a result, it is possible to produce a torsion beam that has fatigue properties superior efficiently.
[0044]
A torsion beam method according to (c) above (a), in the compression processing step, and holds the mounting closed cross-section portion of the torsion beam material, compressing the connecting portion in the longitudinal direction.
　According to the torsion beam manufacturing method, in the compression process, it retains the mount closed cross-section portion of the torsion beam material, so compressing the connecting portion in the longitudinal direction, can be compressed longitudinally inwardly along the entire length of the torsion beam material .
　As a result, it is possible to produce a torsion beam that has fatigue properties superior efficiently.
[0045]
(D) Yet another aspect of the present invention, a pair of left and right arms used torsion beam suspension apparatus is connected to both ends in the longitudinal direction, front and rear cross-section perpendicular to the longitudinal direction in the longitudinal direction of the vehicle body having the shape changing portion which is located between the central portion and the mounting closed cross-section portion of the substantially V-shaped or substantially U-shaped projecting upper or lower side to the central portion and the mounting closed-section portion between the a torsion beam manufacturing apparatus for manufacturing the torsion beam, the shape change outer side holding member having an outer retaining shape portion which is complementarily formed to the shape changing portion, the longitudinal direction of the shape-changing portion is provided in the mold comprising a shape-changing portion support member for supporting by sandwiching from inside, a drive unit for advancing and retracting the attachment closed-section portion holding member in the longitudinal direction of the torsion beam material, and a control unit, wherein the control unit Moving said After forming the torsion beam material, the shape-changing portion supporting member in the longitudinal direction inwardly of the torsion beam material while holding said shaped changing part by the shape-changing portion supporting member and the shape change outer side holding member It is configured to.
[0046]
　According to the torsion beam device, by holding the shape change outer side holding member having an outer retaining shape portion which is complementarily formed to the shape changing portion, the shape changing unit provided in the mold from the longitudinal inner support the shape-changing portion support member while holding the shape changing portion, since the connecting portion by moving the shape-changing portion support member in the longitudinal direction inwardly of the torsion beam material is compressed in the longitudinal direction, the shape changing portion is deformed it can stably be compressed to suppress.
　As a result, it is possible to produce a torsion beam that has fatigue properties superior efficiently.
[0047]
(E) still further aspect of the present invention, a pair of left and right arms used torsion beam suspension apparatus is connected to both ends in the longitudinal direction, front and rear cross-section perpendicular to the longitudinal direction in the longitudinal direction of the vehicle body having the shape changing portion which is located between the central portion and the mounting closed cross-section portion of the substantially V-shaped or substantially U-shaped projecting upper or lower side to the central portion and the mounting closed-section portion between the a torsion beam manufacturing apparatus for manufacturing the torsion beam, a mounting closed cross-section portion holding member which holds the mounting closed-section portion, a driving unit for advancing and retracting the attachment closed-section portion holding member in the longitudinal direction of the torsion beam material, and a control unit , wherein the control unit is configured in a state where mounting closed-section portion holding member is holding the mounting closed cross-section portion, it is configured to compress the torsion beam material longitudinally That.
[0048]
　According to the torsion beam device, it is possible to hold the mounting closed cross-section portion of the torsion beam material, so compressing the connecting portion in the longitudinal direction and longitudinally compressed inward over the entire length of the torsion beam material.
　As a result, it is possible to produce a torsion beam that has fatigue properties superior efficiently.
[0049]
(F) further aspect of the present invention, a pair of left and right arms used torsion beam suspension apparatus is connected to both ends in the longitudinal direction, front and rear cross-section perpendicular to the longitudinal direction in the longitudinal direction of the vehicle body and the central portion of the substantially V-shaped or substantially U-shaped projecting upper or lower side between the mounting closed cross-section portion, and a shape changing unit which is positioned between the mounting closed-section portion and the central portion , a torsion beam manufacturing apparatus for manufacturing the torsion beam having a mold for molding a torsion beam material having said shape changing part and the central portion of the metal material tube is pressed, the shape change is provided in the mold a shape-changing portion support member for supporting and clamping the parts from the longitudinal inner shape change portion support member for advancing and retracting the shape-changing portion support member provided in the mold in the longitudinal direction And the dynamic part is capable of being inserted into the inside of the shape changing part includes an inner support member for holding the shape change unit in cooperation with the shape-changing portion support member, and a control unit, said control parts are moved, after forming the torsion beam material, the shape-changing portion supporting member in the longitudinal direction inwardly of the torsion beam material while holding said shaped changing part by the inner support member and the shape-changing portion support member It is configured to.
[0050]
　According to the torsion beam manufacturing apparatus, the control unit, after forming the torsion beam material a metal material tube is pressed in a state where the shape change portion support member and the inner support member holding the shape changing portion cooperate since compressed longitudinally inward torsion beam material by the drive unit, the residual tensile stress from the connection portion can be reduced or removed.
　As a result, it is possible to produce a torsion beam that has fatigue properties superior efficiently.
[0051]
(G) torsion beam suspension apparatus a pair of right and left arms used is connected to both ends in the longitudinal direction, protruding between the front and rear ends to the upper or lower side in the longitudinal direction of the cross-section body that is perpendicular to the longitudinal direction torsion beam manufacturing to produce a torsion beam having a shape changing unit which is located between the central portion of the substantially V-shaped or substantially U-shaped, and attached closed cross-section portion, and the attachment closed-section portion and the central portion is an apparatus comprising a mold for molding the torsion beam material having said shape changing part and the central portion of the metal material tube and pressed by sandwiching the shape changing unit is provided in the longitudinal direction inside the mold a shape-changing portion support member for supporting the shape-changing portion supporting member driving unit for advancing and retracting the shape-changing portion support member provided in the mold in the longitudinal direction, of the shape-changing portion Is capable inserted towards, the shape-changing portion support member in cooperation with and a inner support member that holds said shape changing part, the shape-changing portion support portion driving portion, the mold torsion beam material It is constituted by a cam mechanism operated by the stroke during molding the.
[0052]
　According to the torsion beam manufacturing apparatus, after forming the torsion beam material a metal material tube is pressed, the cam mechanism is actuated by the stroke in molding the torsion beam material, the shape-changing portion support member and the inner support member since it compressed longitudinally inwardly by a drive unit torsion beam material while holding the shape changing portion cooperate residual tensile stress from the connection portion can be reduced or removed.
　As a result, it is possible to produce a torsion beam that has fatigue properties superior efficiently.
[0053]
(H) a torsion beam manufacturing apparatus according to any one of the above (d) ~ (g), when compressing said torsion beam material longitudinally, shape change absorbing means is displaced along with the longitudinal direction of the shape change It is equipped with a.
[0054]
　According to the torsion beam manufacturing apparatus, when compressing the torsion beam material in the longitudinal direction, is provided with the shape change absorbing means is displaced along with the longitudinal direction of the shape change, there in case of a large longitudinal center side of the shape of the torsion beam also, it is possible to easily compressed.
　Further, torsion beam material when compressed by suppressing that hurt, efficient residual stress can be reduced.
The invention's effect
[0055]
　According to the torsion beam manufacturing method and torsion beam manufacturing apparatus according to the above embodiment, it is possible to produce an excellent torsion beam fatigue properties more efficiently.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056]
FIG. 1 is a perspective view illustrating a schematic configuration of a torsion beam type rear suspension apparatus according to a first embodiment of the present invention.
[Figure 2] A diagram illustrating a schematic configuration of a torsion beam assembly according to the embodiment is a perspective view from below.
3 is a perspective view illustrating a schematic configuration of a torsion beam according to the embodiment.
4 is a perspective view illustrating a schematic configuration of the shape changing portion of the torsion beam according to the embodiment.
[Figure 5A] A diagram showing a schematic configuration of a torsion beam according to the embodiment, a closed cross-section view when viewed in arrow VA-VA in FIG.
[Figure 5B] A diagram showing a schematic configuration of a torsion beam according to the embodiment, a closed cross-section view when viewed in arrow VB-VB of FIG.
[Figure 5C] A diagram showing a schematic configuration of a torsion beam according to the embodiment, a closed cross-section view when viewed in arrow VC-VC in FIG.
6 is a flowchart illustrating an example of a torsion beam of the manufacturing process according to the embodiment.
7 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus according to the embodiment.
[Figure 8] A drawing showing the essential components of the torsion beam manufacturing apparatus according to the embodiment, it is a longitudinal sectional view taken in the arrow X1-X1 in FIG.
[Figure 9] A diagram for explaining along the flow of the compression process (A) ~ (E) of the torsion beam manufacturing method according to the embodiment and is a view corresponding to part A of FIG.
FIG. 10 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus according to a second embodiment of the present invention.
[FIG 11A] A diagram showing a main portion of the torsion beam manufacturing apparatus according to the embodiment, is a longitudinal sectional view taken in the arrow X2-X2 in FIG. 10.
[Figure 11B] A diagram showing a main portion of the torsion beam manufacturing apparatus according to the embodiment, is a longitudinal sectional view taken in the arrow X3-X3 in FIG. 10.
[Figure 12] A drawing will be described along the flow of the manufacturing steps of the torsion beam according to the embodiment (A) ~ (D), it is a view corresponding to part B of FIG. 10.
13 is a flowchart for explaining a manufacturing process of the torsion beam according to a third embodiment of the present invention.
14 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus according to the embodiment.
[15] a view showing a torsion beam manufacturing apparatus according to the embodiment, is a longitudinal sectional view seen in arrow X3A-X3A in FIG.
[Figure 16] A drawing will be described along the flow of the steps of the torsion beam manufacturing method according to the embodiment (A) ~ (E), is a view corresponding to the C section of FIG. 14.
17 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus according to a fourth embodiment of the present invention.
[Figure 18] A drawing will be described along the flow of the steps (A) ~ (E) of the torsion beam manufacturing method according to the embodiment and is a view corresponding to part D of Figure 17.
19 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus according to a fifth embodiment of the present invention.
[Figure 20] A drawing will be described along the flow of the steps (A) ~ (E) of the torsion beam manufacturing method according to the embodiment and is a view corresponding to part E of FIG. 19.
21 is a diagram for explaining along the flow of the steps (A) ~ (D) of the torsion beam manufacturing method according to the sixth embodiment of the present invention.
[Figure 22] A diagram showing a torsion beam manufacturing apparatus according to the embodiment, is a longitudinal sectional view taken in the arrow X4-X4 in FIG. 21.
23 is a diagram for explaining along the flow of the steps (A) ~ (D) of the torsion beam manufacturing method according to a seventh embodiment of the present invention.
[Figure 24] A diagram showing a torsion beam manufacturing apparatus according to the embodiment, is a longitudinal sectional view taken in the arrow X5-X5 in FIG. 23.
[FIG 25 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus according to the eighth embodiment of the present invention.
[FIG. 26] is a front view illustrating a schematic configuration of a modification of the compression processing unit.
[27] using a cam mechanism, a front view illustrating a schematic configuration of a modification of the compression processing unit.
The modification of FIG. 28 the present invention there is provided a graph showing a case of application to the second embodiment, showing a portion corresponding to the G portion of FIG. 10. (A) represents the step of grasping by forming a step portion in the tube end, shows a step of compressing the tube end after gripping (B).
In [29] Example a view for explaining the site of measurement of the stress is a longitudinal sectional view of the connection portion.
[Figure 30] A graph showing the results of Example, graph showing distortion amount was added axial pressing against the torsion beam material and (%), the relationship between the residual stress reduction amount by the axial pressing (%) it is.
DESCRIPTION OF THE INVENTION
[0057]

　Hereinafter, with reference to FIGS. 1-9, a first embodiment will be described of the present invention.
　Figure 1 is a diagram showing a schematic configuration of a torsion beam type rear suspension apparatus according to the present embodiment (torsion beam suspension apparatus), reference numeral 1 denotes a torsion beam type rear suspension apparatus, reference numeral 2 denotes a torsion beam assembly, reference numeral 10 shows a torsion beam. Reference numeral F shown in FIG. 1 shows the front of the vehicle (not shown) that the torsion beam type rear suspension apparatus 1 is mounted, reference numeral R represents the rear.
[0058]
　Torsion beam type rear suspension apparatus 1, as shown in FIG. 1, includes a torsion beam assembly 2, a spring 3 and absorber and 4 for connecting the torsion beam assembly 2 and the vehicle body (not shown), a.
[0059]
　The torsion beam assembly 2, the left and right wheels WL, to support the by the left and right pair of trailing arms 5 WR, pivot shaft JL extending slightly toward the front center side from the left and right of the vehicle body, is connected to the vehicle body via the JR ing. The torsion beam assembly 2 is configured to be swingable with respect to the vehicle body.
[0060]
　The torsion beam assembly 2, as shown in FIG. 2, for example, a pair of left and right trailing arms (arm) 5, and torsion beam 10 for connecting the these trailing arm 5, a pair of left and right spring receiver for supporting the spring 3 and a 3A. Further, one end side of the absorber 4 is a buffer device is connected to a buffer receiving portion (not shown).
　In the present embodiment, the torsion beam 10 has a closed cross section of the substantially V-shape is convex upward.
[0061]
　Trailing arm 5, as shown in FIG. 2, for example, a pivot mounting member supported and the trailing arm body 5A, connected to the front end of the trailing arm body 5A in the vehicle body via a pivot shaft J and 5F, is coupled to the rear end wheel WL of the trailing arm body 5A, and a wheel mounting member 5R supporting the WR.
[0062]
　Spring receiver 3A is arranged on the opposite side of the pivot mounting members 5F sandwiched between the torsion beam 10, one end of the spring 3 is mounted. Load received from the road surface is, the wheels WL, WR, trailing arm 5, and is transmitted to the vehicle via a spring 3.
[0063]
　Referring to FIGS 5C, described torsion beam 10 according to this embodiment.
　Figure 3 is a perspective view illustrating a schematic configuration of the torsion beam 10 according to this embodiment. Figure 4 is a perspective view illustrating the shape changing part schematic of the vicinity of the torsion beam 10. 5A, 5B, 5C is a cross-sectional view showing a torsion beam 10, FIG. 5A shows a cross-sectional view at arrow VA-VA in FIG. 4, FIG. 5B is in arrow VB-VB in FIG. 4 shows a cross-sectional view, Figure 5C is a cross sectional view taken along the plane arrow VC-VC in FIG.
[0064]
　Torsion beam 10, as shown in FIGS. 3 and 4, the central portion 11 of the longitudinal center side is formed substantially V-shaped, the shape changing portion 12, a mounting closed cross-section portion 13, mounting the closed-section portion 13 of formed at the outer end has a closed cross section of substantially elliptical, and a mounting portion 14 trailing arm 5 is attached.
[0065]
　Central unit 11, when viewed torsion beam 10 in the cross section perpendicular to the longitudinal direction, a substantially constant closed cross section of the substantially V-shaped or substantially U-shaped and is formed continuously along the longitudinal direction it may be a part. Incidentally, in the central portion 11, the valley portions of the wall portion constituting the concave side of the substantially V-shaped or substantially U-shaped (bottom), partial unevenness may be formed.
[0066]
　Shape changing unit 12, a valley portion of the wall portion constituting the concave side of the substantially V-shaped or substantially U-shaped depth (bottom), gradually shallower toward the longitudinal outside (vehicle width direction outside) it is made part. Incidentally, in the middle of the shape changing portion 12, portions of valleys (bottom) is further shallower may be partially formed.
[0067]
　Mounting closed-section portion 13 is disposed longitudinally outward of the shape-changing portion 12 (the vehicle width direction outside), it refers to a moiety that is concave having a substantially V-shaped or substantially U-shaped not formed.
[0068]
　Central portion 11, the shape changing portion 12, the attachment closed cross-section portion 13, mounting portions 14 are disposed in this order toward both ends from the longitudinal center of the torsion beam 10.
[0069]
　Central unit 11, as shown in FIGS. 3 and 4, are located in the central longitudinal direction of the torsion beam 10 is connected to each shape changing portion 12 at its longitudinal ends.
　Central portion 11, together with the cross section perpendicular to the longitudinal direction of the torsion beam 10 is formed into a substantially V-shape, in this embodiment, for example, has a shape which is symmetrical in the longitudinal direction of the vehicle body.
[0070]
　Section of the central portion 11 is, for example, in the closed section of the substantially V-shape shown in FIG. 5A, the first wall portion S110A forming a concave side inner surface, a second wall portion S120A forming the convex side outer surface, these first wall and a two folded wall portion S130A that bulges outward in the closed section together with the connection between parts S110A and second wall portions S120A of both ends. Circumferential center portion of the first wall portion S110A is a valley portion of the concave side of the substantially V-shaped (bottom) S111A in the central portion 11.
　Then, the first wall portion S110A and the second wall portion S120A, are in contact with each other via the contact portion S150A.
[0071]
　Each folded-back wall portions S130A is a range indicated by an arrow in FIG. 5A, each are formed between the first wall portion side turn point a and the second wall portion side turn point b.
　The first wall portion folding point a is a connection point between the edge of the edge and the folded wall portion S130A of the first wall portion S110A. The second wall portion side turn point b is a connection point between the edge of the edge and the folded wall portion S130A of the second wall portion S120A.
[0072]
　Connecting portion 12A shown in FIG. 4 (connection area) is included in the shape changing portion 12, a central portion 11 and a shape changing portion 12 is positioned on the side which is connected in shape-changing portion 12, central portion 11 and the shape change a portion including the boundary parts 12. That is, the connecting portion 12A, as shown in FIG. 4, a substantially V from a cross-sectional S12A is the boundary between the central portion 11 and the shape changing portion 12, longitudinal middle position of the shape-changing portion 12 (e.g., in the shape changing portion 12 valleys of the wall portion constituting the concave side of the shaped or substantially U-shaped (bottom) is gradually shallow, a portion extending position) of the cross section S12C to migrate to form inclined with respect to the longitudinal direction.
　Range of the connection portion 12A may be arbitrarily set based on the distribution and the like of the tensile residual stress. For example, connecting unit 12A, a tensile residual stress in the shape changing part 12 may include a portion which becomes maximum. Further, the range of the connection portion 12A may be a predetermined range from the boundary of the central portion 11 and a shape changing part 12 includes a portion where residual tensile stress in the shape-changing portion 12 is maximized and the central portion 11 and the shape change it may be a predetermined range from the boundary parts 12.
[0073]
　Sectional S12B included in the connection part 12A, for example, as shown in FIG. 5B, a first wall portion S110B forming a concave side inner surface at the closed section of the substantially V-shaped, the second wall portion forming the convex side outer surface in the closed section and S120b, and a two folded wall portion S130B that bulges outward in the closed section together with the connecting across these first wall portion S110B and the second wall portion S120b. Also, the circumferential center portion of the first wall portion S110B is the valley of the concave side of the substantially V-shaped (bottom) S111B at connection 12A.
　Then, between the first wall portion S110B and the second wall portion S120b, the hollow portion S150B is formed.
[0074]
　Each folded-back wall portions S130B is a range indicated by an arrow in Figure 5B, they are respectively formed between the first wall portion side turn point a1 and the second wall portion side turn point b1.
　The first wall portion folding point a1 is a connection point between the edge of the edge and the folded wall portion S130B of the first wall portion S110B. The second wall portion folding point b1 is a connection point between the edge of the edge and the folded wall portion S130B of the second wall portion S120b.
[0075]
　As shown in FIG. 4, the shape changing portion 12, the longitudinal inboard torsion beam 10 is connected to the central portion 11, towards the longitudinal outer is connected to the mounting closed cross-section portion 13.
　The shape changing portion 12, the shape of the closed cross section perpendicular to the longitudinal direction of the torsion beam 10 is adapted to migrate gradually from the center portion 11 to the mounting closed cross-section portion 13.
[0076]
　Shape changing unit 12, for example, as shown in FIG. 5C, a first wall portion S110C forming a concave side inner surface at the closed section of the substantially V-shaped, and the second wall portion S120C forming the convex side outer surface in the closed section , and a two folded wall portion S130C that bulges outward in the closed section together with the connection between the first wall portion S110C and second wall portions S120C of both ends. Also, the circumferential center portion of the first wall portion S110C is the valley of the concave side of the substantially V-shaped (bottom) S111c.
　Then, between the first wall portion S110C and the second wall portion S120c, the hollow portion S150C is formed.
[0077]
　Folded wall portion S130C is a range indicated by an arrow in FIG. 5C, it is respectively formed between the first wall portion side turn point a2 and the second wall portion side turn point b2.
　The first wall portion folding point a2 is a connecting point between the edge of the edge and the folded wall portion S130C of the first wall portion S110c. The second wall portion folding point b2 is a connection point between the edge of the edge and the folded wall portion S130C second wall portion S120c.
[0078]
　As shown in FIG. 4, the attachment closed cross-section portion 13, for example, the longitudinal direction outward of the shape-changing portion 12 is located in (the vehicle width direction outside), the concave substantially V-shaped or substantially U-shaped It has a closed cross section of substantially elliptical shape without.
[0079]
　Next, referring to FIG. 6, illustrating an example of a manufacturing process of the torsion beam 10 according to the first embodiment. Figure 6 is a flow chart showing an example of a manufacturing process of the torsion beam 10.
[0080]
　Referring to FIG 6, a description will be given of a manufacturing process of the torsion beam 10.
(1) preparing a metal material tube (step S101). The metal material pipe to be prepared, for example, it is possible to wall thickness used uniform Tubular.
(2) Next, in the pressing step, pressing a metal material tube (step S102). Forming a torsion beam material by pressing a metal material tube. Press working, it is possible to use a known press machine.
By pressing in (3) Step S102, the torsion beam material is formed (step S103). Torsion beam material has a central portion has a shape changing portion, and a mounting closed cross-section portion, connecting portions for connecting the central portion and the shape-changing portion (connection area) is formed.
(4) Then, in the compression process, by axially compressed state without applying a fluid pressure to the interior of the torsion beam material, which compresses the torsion beam material (step S104). In this compression process, the torsion beam material, to provide a 2.0% strain of 0.5% or more in its axial buckling (buckling) without causing residual stress in the front and back surfaces in the thickness direction it becomes possible to release the. The compression force in the longitudinal direction of the torsion beam material, may be added only to the portion desired to particularly reduce the residual stress, it was added over the entire length as in this embodiment, no leak of residual stresses as a whole more preferable in that it can be reduced.
(5) by compressing the torsion beam material in step S104, the torsion beam 10 is formed (step S105).
[0081]
　Next, with reference to FIGS. 7 and 8, will be described a schematic configuration of a torsion beam manufacturing apparatus according to the first embodiment. Figure 7 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus 100 according to the first embodiment. Further, FIG. 8 is a view showing a torsion beam manufacturing apparatus according to the embodiment, is a longitudinal sectional view taken in the arrow X1-X1 in FIG.
[0082]
　The torsion beam manufacturing apparatus 100 is provided with a torsion beam element supporting stand 110 for mounting the torsion beam material W10, and two compression unit 120 for compressing the torsion beam material W10 in its longitudinal direction, control unit (not shown).
[0083]
　Torsion beam material supporting table 110, it has been recesses 110U is formed corresponding to the outer shape of the torsion beam material W10 at the top, a torsion beam material W10 placed on the recessed portion 110U stably supported.
　In the description of the torsion beam material W10 below, to distinguish them from the torsion beam 10, the central portion 11 of the torsion beam 10, the shape changing portion 12, the attachment closed cross-section portion 13, the portion corresponding to each part of the mounting portion 14, respectively , the central portion 11W, the shape changing portion 12W, mounting closed cross-section portion 13W, be described by changing the mounting portion 14W and the code.
[0084]
　As shown in FIG. 8, recesses 110U is the cross-sectional shape at an arbitrary position in the longitudinal direction has a substantially V-shaped or substantially U-shaped. The cross-sectional shape is consistent with the longitudinal sectional shape of the central portion 11W and the shape changing portion 12W of the torsion beam material W10. More specifically, the supporting surface 110U1 for supporting the central portion 11W and the shape changing portion 12W respective outer surface wa, a support surface 110U2 for supporting the central portion 11W and the shape changing portion 12W respective outer surfaces wb is, recesses It is formed in the 110U. These support surfaces 110U1,110U2 are connected to each other in these bottom edge.
　As shown in FIG. 7, recesses 110U of the torsion beam material supporting table 110 is mounted closed cross-section portion 13W and the mounting portion 14W is not supported. This is to hold both ends of the torsion beam material W10 by mounting closed-section portion holding member 121 described later.
[0085]
　Compression processing unit 120, as shown in FIG. 7, the mounting closed cross-section portion holding member 121 for holding the mounting closed-section portion 13W of the torsion beam material W10, torsion beam material W10 mounting closed cross-section portion holding member 121 along the arrow T120 hydraulic cylinder for the forward and backward in the longitudinal direction (first driving mechanism) 125, and a the controller. Operation of the compression processing unit 120 is controlled by the control unit.
[0086]
　Mounting closed-section portion holding member 121, the attachment member having a shape corresponding to the internal shape of the attachment closed cross-section portion 13W in the longitudinal direction of the torsion beam material W10 from the bottom of the recess 121U is formed closed cross-section portion holding member main body 121A When provided with a plurality of sets of clamping members 121B and the clamping member 121C which face each other, the.
[0087]
　Clamping member 121B, the drive unit such as an actuator be connected to the (not shown), which is retractable from the wall of the mounting closed-section portion holding member main body 121A inwardly.
[0088]
　Clamping member 121C is driven unit such as an actuator be connected to the (not shown), which is retractable from the convex portion of the attachment closed-section portion holding member main body 121A outward.
[0089]
　Clamping member 121B and the clamping member 121C is near mounting portion 14W of the attachment closed-section portion 13W of the torsion beam material W10, pinching and holding cooperate from the outside and inwardly. This by holding to, the central axis of the central axis of the mounting portion 14W and the attachment closed cross-section portion holding member main body 121A can be matched. That is, it is possible to hold the coaxial mounting closed cross-section portion 13W by mounting closed-section portion holding member 121. Moreover, the mounting portion 14W of the case this is in contact with the bottom of the recess 121U.
[0090]
　Hydraulic cylinder (first driving mechanism) 125, when receiving an instruction from the control unit, the mounting closed cross-section portion holding member 121, it is moved forward and backward in the longitudinal direction of the torsion beam material W10 along the arrow T120.
[0091]
　That is, by the control unit, a pair of mounting closed-section portion holding member 121 while holding each mounting closed-section portion 13W at the ends of the torsion beam material W10, it is longitudinally compressed by the bottom of the recess 121U. At this time, the central portion 11W and the shape changing portion 12W, so subjected to compressive forces while being supported by the recess 110U, no buckling. Further, since the mounting closed cross-section portion 13W by mounting closed cross-section portion holding member 121 are both its inner and outer surfaces are supported, no buckling as well. The compressive force torsion beam material W10 in a state of preventing buckling is given so, it is possible to eliminate or reduce residual stress of at least the central portion 11W and the shape changing portion 12W. In addition, also performed at the same time thickening of at least the central portion 11W and the shape changing portion 12W. This thickening, the outer surface wa of the central portion 11W and the shape changing portion 12W, since wb is supported and meat increased as inner dimensions shrinks in a state where the cross-sectional profile dimensions are maintained. Thus, enabling the thickening on maintaining the external dimensions to the design scale.
[0092]
　In the present embodiment, a configuration to apply a compressive force from both ends of the torsion beam material W10, mounting closed cross-section portion which is not limited to this embodiment, a pair of mounting closed-section portion holding member 121 at both ends of the torsion beam material W10 after holding each 13W, fixing the position of one of the pair of attaching the closed-section portion holding member 121, by relatively approaching the other to the one, it adopted the form to compress the torsion beam material W10 possible it is. This point, other embodiments are also the same.
[0093]
　Next, referring to FIG. 9 (A) ~ FIG 9 (E), an outline of the compression process using the torsion beam manufacturing apparatus 100. Figure 9 (A) ~ FIG 9 (E) are views for explaining along the flow of the compression process FIG 9 (A) ~ FIG 9 (E) in the torsion beam manufacturing method, the part A of FIG. 7 is a diagram corresponding. The compression process below, by the control unit may be all carried out automatically.
[0094]
(1) First, after the support by placing the torsion beam material W10 on the torsion beam material supporting table 110, as shown in FIG. 9 (A), to advance the attached closed cross-section portion holding member 121 in the arrow T120F direction.
(2) Next, as shown in FIG. 9 (B), the mounting portion 14W of the attachment closed cross-section portion 13W in the bottom of the recess 121U is When in contact, to stop the mounting closed cross-section portion holding member 121.
　Then, the clamping member 121B and the clamping member 121C is protruded as shown by an arrow, to hold the mounting closed cross-section portion 13W.
[0095]
(3) Next, as shown in FIG. 9 (C), After holding the mounting closed cross-section portion 13W by clamping members 121B and the clamping member 121C, a torsion beam material W10 by operating the hydraulic cylinder (not shown) in the longitudinal direction along compresses the arrow T120P direction. In this compression process, the torsion beam material W10, by giving more than 2.0% strain of 0.5% or more in its axial direction, without causing buckling, release the residual stress in the front and back surfaces in the thickness direction it is possible to. Also, when pushing the shaft, for mounting closed cross-section portion 13W sandwiches by the clamping member 121B and the clamping member 121C, out-of-plane deformation of the mounting closed-section portion 13W is suppressed.
(4) When the compression of the torsion beam material W10 is completed, has finished the torsion beam 10. Thereafter, as shown in FIG. 9 (D), it is retracted to indicate clamping member 121B and the clamping member 121C to the arrow. Thereby, the holding of the attachment closed-section portion 13W according to attach the closed-section portion holding member 121 is released.
(5) When the clamping member 121B and the clamping member 121C is retracted to a predetermined position, as shown in FIG. 9 (E), with the mounting closed cross-section portion holding member 121 is retracted in the arrow T120R direction, the compression process is completed.
[0096]
　Torsion beam manufacturing method according to the first embodiment, and according to the torsion beam manufacturing apparatus 100, it is possible to manufacture the torsion beam 10 that is fatigue characteristics excellent efficiently. Since the effect of reducing the residual stress can be obtained by compression, has the effect of generating a torsion beam while the vehicle is traveling (the load to) stress is reduced, further improvement in fatigue properties can be expected. Yet, since the thickening effect can be obtained simultaneously by compression, it has become possible to increase the structural strength of the torsion beam.
[0097]
　Further, torsion beam manufacturing method according to the first embodiment, and according to the torsion beam manufacturing apparatus 100, and holds the mounting closed-section portion 13W of the torsion beam material W10, since compressing the connecting portion 12A in the longitudinal direction, the torsion beam material W10 It can be compressed over the entire length. As a result, it is possible to remove the residual tensile stress without leakage at the central portion 11W, the entire range of shape changing portion 12W of the torsion beam material W10.
[0098]

　Next, with reference to FIGS. 10 to 12, a description of a second embodiment of the present invention.
　Figure 10 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus 100A according to a second embodiment of the present invention. Figure 11A is a diagram showing a main part of the torsion beam manufacturing devices 100A, it is a longitudinal sectional view taken in the arrow X2-X2 in FIG. 10. Figure 11B is a diagram showing a main part of the torsion beam manufacturing devices 100A, it is a longitudinal sectional view taken in the arrow X3-X3 in FIG. 10. Figure 12 is a diagram for explaining along the flow of the manufacturing steps of the torsion beam according to the embodiment (A) ~ (D), it is a view corresponding to part B of FIG. 10.
　The second embodiment differs from the first embodiment, a method of holding the torsion beam material W10 when compressing the torsion beam material W10 is different.
[0099]
　Referring to FIGS. 10 to 11B, illustrating a schematic configuration of the torsion beam manufacturing apparatus 100A according to the second embodiment.
　The torsion beam manufacturing apparatus 100A, as shown in FIG. 10, the torsion beam material supporting table 1213 for mounting the torsion beam material W10, a pair of compression processing unit 120A for compressing the torsion beam material W10 longitudinally, the control unit (not shown) It is equipped with a door.
[0100]
　Torsion beam material support table 1213, have been recesses 1213U is formed corresponding to the outer shape of the torsion beam material W10 at the top, a torsion beam material W10 placed on the recess 1213U supported stably. However, recess 1213U supports the only central portion 11W and near both ends portions thereof. This is to hold both ends of the torsion beam material W10 by shape change outer side holding member 1210 described later.
[0101]
　As shown in FIG. 11A, the recess 1213U is the cross-sectional shape at an arbitrary position in the longitudinal direction has a substantially V-shaped or substantially U-shaped. The cross-sectional shape is consistent with the lower cross-sectional shape of the central portion 11W and near both ends portions thereof of the torsion beam material W10. More specifically, the supporting surface 1213U1 for supporting the respective outer surface wa of part of the central portion 11W and the shape changing portion 12W, the respective outer surface wb of part of the central portion 11W and the shape changing portion 12W support a support surface 1213U2 which is formed in the recess 1213U. These support surfaces 1213U1,1213U2 are connected to each other in these bottom edge.
[0102]
　Compression processing unit 120A, as shown in FIG. 10, a change in shape outer side holding member 1210 that holds the shape changing portion 12W and attached closed-section portion 13W from outside, the shape changing portion 12W and mounting the closed-section portion 13W a shape changing portion supporting the punch (inner support member) 122 which supports from the inside, along a shape change portion supporting the punch 122 in the longitudinal direction of the torsion beam material W10 and a hydraulic cylinder 125 for advancing and retracting the arrow T120 direction.
[0103]
　Shape change outer side holding member 1210 includes an upper outer holder 1211 formed corresponding to the upper contour of the shape-changing portion 12W and attached closed-section portion 13W of the torsion beam material W10, shape changing portion 12W and mounting the closed-section portion a lower outer holding portion 1212 formed corresponding to the lower outer shape of 13W, these upper outer holding portion 1211 and the lower outer holding portion 1212 in an arrow T121Y direction (compression direction) and an arrow T121Z (holding direction) driver such as actuators for advancing and retracting is provided with a (not shown) and.
[0104]
　As shown in FIG. 11B, upper outer holding portion 1211 is provided with an upper contour complementary-formed upper bearing surface 1211p shape changing portion 12W and attached closed cross-section portion 13W, are connected to a driving unit (not shown) ing.
　Upper bearing surface 1211p has a longitudinal section of the substantially V-shaped or substantially U-shaped at a position corresponding to the shape changing portion 12W. Further, upper bearing surface 1211p, in the position corresponding to the mounting closed cross-section portion 13W has a longitudinal section of the concave semicircular. Therefore, longitudinal section of the upper bearing surface 1211p is consistent with the upper cross-sectional shape of the shape changing portion 12W and attached closed-section portion 13W of the torsion beam material W10. The upper bearing surface 1211p, among the torsion beam material W10, the first wall portion S110B and a pair of folded wall portions S130B supports from above them.
[0105]
　As shown in FIG. 11B, the lower outer holding portion 1212 has a shape changing portion 12W and attached closed-section portion lower supporting surface 1212p which is complementarily formed to the lower contour of 13W, the driving unit (not shown) It is connected to the.
　Lower support surface 1212p is a vertical sectional shape at an arbitrary position in the longitudinal direction has a substantially V-shaped or substantially U-shaped concave shape. The longitudinal section is consistent with the lower cross-sectional shape of the shape changing portion 12W and attached closed-section portion 13W of the torsion beam material W10. More specifically, the supporting surface 1212p1 for supporting the shape changing portion 12W and attached closed-section portion 13W respective outer surfaces wa, support surface for supporting the shape changing portion 12W and attached closed-section portion 13W respective outer surface wb 1212P2 bets have been formed in the lower support surface 1212P. These support surfaces 1212p1,1212p2 are connected to each other in these bottom edge.
[0106]
　Returning to FIG. 10, the shape changing portion supporting the punch 122, for example, be formed to correspond to the inner shape of the shape changing portion 12W and attached closed cross-section portion 13W, which is insertable into the inside of the radius variations 12W to support the change in shape portion 12W from the inside.
　Specifically, the shape changing portion supporting the punch 122 has an inner shape complementary-formed shape changing portion inner side holding the shape of the shape changing portion 12W.
[0107]
　Compression processing unit 120A is controlled by a control unit (not shown). Specifically, the hydraulic cylinder 125 receives an instruction from the control unit, advancing and retracting the shape-changing portion supporting the punch 122 in the arrow T120 direction.
　The shape changing portion supporting the punch 122, the upper outer holding portion 1211 and the lower outer holding unit 1212, the residual tensile stress in the shape-changing portion 12W may hold the mounting closed cross-section portion 13W side from positions of maximum .
[0108]
　Referring to FIG. 12 (A) ~ FIG 12 (D), a description will be given of an example of a schematic of a torsion beam manufacturing process by torsion beam manufacturing apparatus 100A. Figure 12 (A) ~ FIG 12 (D) are diagrams for explaining the outline of manufacturing steps of the torsion beam according to a second embodiment.
[0109]
(1) First, as shown in FIG. 10 and FIG. 12 (A), the support by placing the torsion beam material W10 on torsion beam material supporting table 110, to arrange the shape change outer side holding member 1210 in position.
(2) Next, as shown in FIG. 12 (B), the shape changing portion supporting the punch 122 is advanced in the arrow T120F direction inserted to the inside of the shape-changing portion 12W, the shape changing portion supporting the punch 122 shape change When you support the part 12W from the inside to stop.
(3) Next, as shown in FIG. 12 (C), by a drive unit (not shown), the upper outer holding portion 1211 and the lower outer holding portion 1212 is advanced in the arrow T121Z direction, these upper outer holding portion 1211 and retaining the shape changing portion 12W and attached closed-section portion 13W from above and below by the lower outer holding portion 1212.
(4) Then, as shown in FIG. 12 (D), as well as supported by the shape changing portion supporting the punch 122 and the shape changing portion 12W and attached closed-section portion 13W from the inside, upper outer holding portion 1211 and the lower outer holding compressing the arrow T121P direction while holding the shape changing portion 12W and attached closed-section portion 13W by part 1212, to form the torsion beam 10. At this time, the shape changing portion supporting the punch 122 includes an upper outer holding portion 1211 and the lower outer holding portion 1212 synchronous or follow to move in the arrow T120R direction. In this compression process, the torsion beam material W10, by giving more than 2.0% strain of 0.5% or more in its axial direction, without causing buckling, the tensile residual stress in the front and back surfaces in the thickness direction it is possible to cancel.
[0110]
　According to the torsion beam manufacturing method and torsion beam manufacturing apparatus 100A according to the second embodiment, it is possible to reduce the residual stress of the connection part 12A, to produce a torsion beam 10 that is fatigue characteristics excellent efficiently.
[0111]
　Further, according to the torsion beam manufacturing devices 100A, by inserting a shape-changing portion supporting the punch 122 to the inside of the shape changing portion 12W and attached closed cross-section portion 13W, the shape changing portion 12W and attachment closed by the shape changing portion supporting the punch 122 supporting the cross section 13W from the inside. Then, the upper outer holding portion 1211 and the lower outer holding portion 1212 while holding the shape changing portion 12W and attached closed cross-section portion 13W, so compressing the torsion beam material W10 in its longitudinal direction, so that the shape changing portion 12W is crushed suppressing the deformation to enable a stable compression processing.
[0112]

　Next, with reference to FIGS. 13 to 16, a description of a third embodiment of the present invention.
　Figure 13 is a flowchart illustrating a torsion beam of the manufacturing process according to a third embodiment of the present invention. Further, FIG. 14 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus 100B according to the present embodiment. Figure 15 is a longitudinal sectional view seen in arrow X3A-X3A in FIG. Figure 16 (A) ~ FIG 16 (E) are diagrams for explaining the outline of manufacturing steps of the torsion beam according to the present embodiment.
[0113]
　In the first embodiment, in advance by molding a torsion beam material W10 performed beforehand stamping, then, it was prepared the torsion beam 10 by compressing the torsion beam material W10 by torsion beam manufacturing apparatus 100. In contrast, in the present embodiment, it is implementing both the pressing and compressing process by the torsion beam manufacturing apparatus 100B. Incidentally, the other points of this embodiment are similar to those of the aforementioned first embodiment.
[0114]
　Referring to FIG. 13, described torsion beam manufacturing process according to the present embodiment.
(1) preparing a metal material tube (step S201). The metal material pipe to be prepared, for example, it is possible to wall thickness used uniform Tubular.
(2) Next, in the pressing and compressing process step, the metallic material tube to the pressing and compression processing (step S202). The pressing and compressing process step, the metallic material tube by forming a torsion beam material W10 by pressing, then, remains in its installed state, subsequently compressing the torsion beam material W10. This compression process, the torsion beam material W10, by giving more than 2.0% strain of 0.5% or more in its axial buckling (buckling) without causing tensile at front and back surfaces in the thickness direction residual stress it is possible to release the. At this time the torsion beam material W10 is compressed in the axial direction in a state not to apply fluid pressure therein.
(3) by a pressing and compressing process in step S202, the torsion beam 10 is formed (step S203).
[0115]
　Next, with reference to FIGS. 14 and 15, will be described a schematic configuration of the torsion beam manufacturing apparatus 100B according to the present embodiment.
　The torsion beam manufacturing apparatus 100B includes, as shown in FIG. 14, a press-forming the fixed mold 110A, a pair of compression processing unit 120, and the press molding movable die drive unit 130A, the control unit (not shown).
　In the torsion beam manufacturing apparatus 100B, a press molding fixed 110A and the press molding movable die drive unit 130A constitute a press machine, a pair of compression processing unit 120 constitute a compression machine.
　Since the configuration and operation of the compression processing unit 120 are the same as those of the first embodiment, a repeated explanation thereof are denoted by the same reference numerals.
[0116]
　Press forming fixed (mold) 110A, the recess is used to obtain the torsion beam material W10 metallic material tube pressing to 110AU is formed. That is, the press-molding fixed 110A, recesses 110AU having a shape corresponding to the lower surface of the torsion beam material W10 is formed faces upward.
　Further, press forming fixed 110A, at the time of compression processing the torsion beam material W10 by a pair of compression processing unit 120 also functions as a torsion beam material support table for supporting the torsion beam material W10.
[0117]
　As shown in FIG. 15, the recess 110AU is a vertical sectional shape is a substantially V-shaped or substantially U-shaped concave shape in the longitudinal direction of the arbitrary position. The longitudinal section is consistent with the lower cross-sectional shape of the central portion 11W and the shape changing portion 12W of the torsion beam material W10. More specifically, the support surface 110A1 that supports the central portion 11W and the shape changing portion 12W respective outer surface wa, a support surface 110A2 that supports the central portion 11W and the shape changing portion 12W respective outer surfaces wb is, recesses It is formed in 110AU. These support surfaces 110A1,110A2 are connected to each other in these bottom edge.
　As shown in FIG. 14, the recess 110AU press molding fixed 110A is mounted closed cross-section portion 13W and the mounting portion 14W is not supported. This is to hold both ends of the torsion beam material W10 by mounting closed-section portion holding member 121.
[0118]
　Press molding movable die drive unit 130A is press-molding movable die (the movable mold) 131, and a hydraulic cylinder (second drive mechanism) 135 for advancing and retracting the press molding movable die 131 in the arrow T130 direction (elevation) there.
　As shown in FIG. 15, the press molding movable die 131 has a shape for forming the torsion beam material W10 on its lower surface, forming a torsion beam material W10 in cooperation with the press molding fixed 110A. The lower surface of the press-molding movable die 131, upper bearing surface 131A having a shape corresponding to the upper surface of the torsion beam material W10 is formed faces downward.
[0119]
　Upper bearing surface 131A has a convex cross-section of substantially V-shaped or substantially U-shaped. Longitudinal section of the upper bearing surface 131A is consistent with the upper cross-sectional shape of the shape changing portion 12W and the central portion 11W of the torsion beam material W10. The upper bearing surface 131A, of the torsion beam material W10, the first wall portion S110B and a pair of folded wall portions S130B supports from above them.
[0120]
　Wherein the control unit (not shown), each compression unit 120 and the press molding movable die drive unit 130A, and instructs the operation relating to pressing and compression process.
[0121]
　Referring to FIG. 16 (A) ~ FIG 16 (E), will be outlined in the torsion beam manufacturing process by torsion beam manufacturing apparatus 100B. Figure 16 (A) ~ FIG 16 (E) is a diagram illustrating a process of producing the torsion beam according to the present embodiment along the flow of FIG. 16 (A) ~ FIG 16 (E), C in FIG. 14 it is a view corresponding to part.
[0122]
(1) First, as shown in FIG. 16 (A), placing a metal material tube W0 onto the press molding fixed 110A, moves the press-molding movable die 131 in the arrow T130F direction (downward).
(2) Next, as shown in FIG. 16 (B), When torsion beam material W10 is molded to move the press-molding movable die 131 in the arrow T130R direction (upward). Then, to advance the attached closed cross-section portion holding member 121 in the arrow T120F direction.
(3) Next, as shown in FIG. 16 (C), When abuts the bottom of the concave portion 121U is near the mounting portion 14W of the attachment closed cross-section portion 13W, stopping advancement of the attachment closed-section portion holding member 121. Then, the clamping member 121B and the clamping member 121C, to protrude in the direction of the arrow so as to approach each other.
(4) Then, as shown in FIG. 16 (D), by sandwiching the attachment closed cross-section portion 13W by clamping members 121B and the clamping member 121C, to retain the vicinity of the mounting portion 14W of the torsion beam material W10.
(5) Then, as shown in FIG. 16 (E), the left while holding the mounting closed cross-section portion 13W by clamping members 121B and the clamping member 121C, by operating the hydraulic cylinder (hydraulic cylinder 125 shown in FIG. 14) the torsion beam material W10 was compressed in the arrow T120P along its longitudinal direction to form a torsion beam 10. In this compression process, the torsion beam material W10, by giving more than 2.0% strain of 0.5% or more in its axial direction, without causing buckling, the tensile residual stress in the front and back surfaces in the thickness direction it becomes possible to release.
　After the formation of the torsion beam 10, FIG. 9 in the first embodiment (D), is the same as the operation described with reference to FIG. 9 (E), the duplicated description thereof is omitted here.
[0123]
　Torsion beam manufacturing method according to the present embodiment, according to the torsion beam manufacturing apparatus 100B, it is possible to manufacture the torsion beam 10 that is fatigue characteristics excellent efficiently.
[0124]
　Further, according to the torsion beam manufacturing apparatus 100B according to the present embodiment, after forming the torsion beam material W10 metallic material tube W0 is pressed without transferring the torsion beam material W10 to other devices, continue to torsion beam material W10 since the production of the torsion beam 10 is compressed, it is possible to improve the productivity.
[0125]

　Next, with reference to FIGS. 17 and 18, a description of a fourth embodiment of the present invention.
　Figure 17 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus 100C according to this embodiment. Figure 18 (A) ~ FIG 18 (E) are diagrams for explaining the outline of the torsion beam manufacturing process according to the present embodiment along the flow of FIG. 18 (A) ~ FIG 18 (E), 17 it is a view corresponding to the D portion.
[0126]
　Referring to FIG 17, it will be described a schematic configuration of the torsion beam manufacturing apparatus 100C according to this embodiment.
　The torsion beam manufacturing apparatus 100C includes a press forming fixed (mold) 110B, a pair of compression processing unit 120B, and the press molding movable die drive unit 130B, the control unit (not shown).
　In the torsion beam manufacturing apparatus 100C, a press molding fixed 110B and the press molding movable die drive unit 130B constitute a press machine, the pair of compression processing unit 120B forms a compression machine.
[0127]
　Press forming fixed (mold) 110B, the recess is used to obtain the torsion beam material W10 metallic material tube W0 pressing to 110BU is formed. That is, the press-molding fixed 110B, recess 110BU having a shape corresponding to the lower surface of the torsion beam material W10 is formed faces upward. Since the detailed cross-sectional shape of the recess 110BU is the same as the recess 110AU described in the third embodiment, a description thereof will be omitted.
　Further, press forming fixed 110B, at the time of compression processing the torsion beam material W10 by a pair of compression processing unit 120B, also functions as a torsion beam material support table for supporting the torsion beam material W10.
[0128]
　Press molding fixed 110B includes a first support portion 111B, a pair having a shape corresponding to the shape changing portion 12W and attached closed-section portion 13W second supporting portion 112B having a shape corresponding to the central portion 11W of the torsion beam material W10 When, a is disposed in the first supporting portion 111B, and a first actuator (shape change absorbing means) such as a hydraulic cylinder for advancing and retracting the second supporting portion 112B in the arrow T112 direction with respect to the support portion 111B 113B. The actuator 113B is provided one for each of the second supporting portion 112B.
[0129]
　Press molding movable die drive unit 130B includes a press-molding movable die (movable die) 132, and a hydraulic cylinder (second drive mechanism) 135 for advancing and retracting the press molding movable die 132 in the arrow T130 direction (elevation) there.
　The lower surface of the press-molding movable die 132, be formed shape corresponding to the upper shape of the torsion beam material W10, obtain torsion beam material W10 metallic material tube W0 pressing to cooperate with a press molding fixed 110B . Incidentally, the lower surface shape of the press-molding movable die 132 is the same as the lower surface shape of the press-molding movable die 131 described in the third embodiment, a description thereof will be omitted. For example, the cross-sectional shape in the view taken along arrow X6-X6 of FIG 17 is the same as the sectional shape described in FIG. 15 of the third embodiment.
[0130]
　Each compression processing unit 120B, respectively, as shown in FIG. 17, advancing and retracting the shape changing portion supporting the punch (inner support member) 122, a shape change portion supporting the punch 122 in the arrow T120 direction along the longitudinal direction of the torsion beam material W10 and a hydraulic cylinder 125 for.
[0131]
　Each shape-changing portion supporting the punch 122, respectively, have been formed in a shape corresponding to the internal shape of the shape changing portion 12W and attached closed cross-section portion 13W, it is inserted into the inside of the shape-changing portion 12W shape changing portion 12W supported from the inside.
　Specifically, the shape-changing portion supporting the punch 122 is provided with an internal shape of the shape changing portion 12W complementarily formed shape changing portion inner side holding-shaped portion, respectively.
[0132]
　Each hydraulic cylinder 125, respectively, by instruction from the control unit (not shown), advancing and retracting the shape-changing portion supporting the punch 122 in the arrow T120 direction.
[0133]
　Press molding the movable mold 132, as shown in FIG. 17, a first molding part 132A, the longitudinal direction respectively on both sides arranged two second mold (shape-changing portion support member) of the first mold portion 132A 132B and , and a pair of hydraulic cylinders the second molding portion 132B is moved in the arrow T132 direction (shape-changing portion supporting member driving unit) 132C.
　The lower surface of the press-molding movable die 132, be formed shape corresponding to the upper shape of the torsion beam material W10, press molding the torsion beam material W10 in cooperation with the press molding fixed 110B.
[0134]
　Wherein the control unit (not shown), each actuator 113B of the press molding fixed 110B, for each compression processing unit 120B, and press-molding movable die drive unit 130B, direct the operation relating to pressing and compression process.
[0135]
　Each actuator 113B is displaced in response to longitudinal shape change due to the molding process of the torsion beam material W10 (shrinkage). Specifically, operating the hydraulic cylinders (shape-changing portion supporting member driving unit) movement of 132C and synchronization or tracking to.
[0136]
　Wherein the control unit includes a respective actuator 113B of the press molding fixed 110B, the hydraulic cylinders (shape-changing portion supporting member driving unit) which is arranged in the press molding movable die 132 and synchronously advancing and retreating 132C.
　Each hydraulic cylinder 125 is operated actuators 113B and the hydraulic cylinders 132C and synchronization or tracking to.
[0137]
　By using the torsion beam manufacturing apparatus 100C according to the fourth embodiment, it is possible to partially compress any portion of the torsion beam material W10, the effect obtained by compression can be focused at a specific site.
[0138]
　Referring to FIG. 18 (A) ~ FIG 18 (E), will be outlined in the torsion beam manufacturing process by torsion beam manufacturing apparatus 100C. Figure 18 (A) ~ FIG 18 (E) are views for explaining along the flow of the manufacturing steps of the torsion beam according to the present embodiment FIG. 18 (A) ~ FIG 18 (E), in Fig. 17 it is a view corresponding to D unit.
[0139]
(1) First, as shown in FIG. 18 (A), placing a metal material tube W0 for press molding fixed 110B on, moving the press forming movable mold 132 in the arrow T130F direction.
(2) Then, as shown in FIG. 18 (B), the torsion beam material W10 is press-formed by sandwiching a metal material tube W0 between the press molding fixed 110B and the press molding movable die 132.
(3) Next, as shown in FIG. 18 (C), the shape changing portion supporting the punch 122 is advanced in the arrow T120F direction inserted up to the inside of the shape-changing portion 12W. As a result, the shape changing portion supporting the punch 122 comes into contact with the shape-changing portion 12W of the torsion beam material W10, it supports the shape changing portion 12W and attached closed-section portion 13W from the inside thereof.
[0140]
(4) Then, as shown in FIG. 18 (D), by cooperating hydraulic cylinders 132C and the actuator 113B, and retracting the second molding portion 132B in the arrow T132P direction, shape changing portion supporting the punch 122 and the second the molding portion 132B in a state of supporting the shape changing portion 12W compressing torsion beam material W10 longitudinally. Further, the second support portion 112B to form a torsion beam 10 retreats in the arrow T112P direction in synchronization with the second molding portion 132B. At this time, the shape changing portion supporting the punch 122, further advanced in the arrow T120F direction in synchronization with the second molding portion 132B and the second supporting portion 112B.
　In this compression process, the torsion beam material W10, by giving more than 2.0% strain of 0.5% or more in its axial direction, without causing buckling, the tensile residual stress in the front and back surfaces in the thickness direction it becomes possible to release. In addition, the central portion 11W and the shape changing portion 12W respective outer surface wa of the torsion beam material W10, from the fact that over compression on supporting the wb, buckling does not easily occur.
(5) After forming the torsion beam 10, as shown in FIG. 18 (E), to retract the shape-changing portion supporting the punch 122 in the arrow T120R direction. Also, it makes move the press molding movable die 132 in the arrow T130R direction (up).
[0141]
　Above from (2) (4) That is, in the state of FIG. 18 (D) from FIG. 18 (B), the central portion 11W of the torsion beam material W10 is held by the first mold portion 132A and the first supporting portion 111B . The shape changing portion supporting the punch 122, the second molding portion 132B and the second supporting portion 112B, is compressed in a state where the shape change portion 12W of the torsion beam material W10 was retained performed. Thus, among the torsion beam material W10, sites not retained is to be partially compressed.
[0142]
　Torsion beam manufacturing method according to the present embodiment, according to the torsion beam manufacturing apparatus 100C, it is possible to manufacture the torsion beam 10 that is fatigue characteristics excellent efficiently. Furthermore, by sites that are not held by a die among the torsion beam material W10 it is partially compressed, since the partial thickening is obtained, has become possible to increase the structural strength of the torsion beam.
[0143]
　Further, according to the torsion beam manufacturing apparatus 100C, since compressing the shape changing portion supporting the punch 122 and the torsion beam material W10 in a state where the second molding portion 132B holds the shape changing portion 12W cooperate in the longitudinal direction, the connecting portion tensile residual stress of 12A can be reduced or removed, it is possible to obtain a high dimensional accuracy torsion beam.
[0144]
　Further, according to the torsion beam manufacturing apparatus 100C, when compressing the torsion beam material W10 longitudinally is provided with the actuator 113B displaced with the shape change in the longitudinal direction due to the compression process of the torsion beam material W10, of the torsion beam W10 even when the outer shape of the longitudinally defined center region is smaller than its neighboring, it can be easily compressed.
[0145]
　Further, according to the torsion beam manufacturing apparatus 100C, is provided with the actuator 113B, to suppress the torsion beam material W10 is being damaged during the compression process, efficiently residual stress can be reduced.
[0146]
　Further, according to the torsion beam manufacturing apparatus 100C, after forming the torsion beam material W10 metallic material tube W0 pressing to, can be manufactured with torsion beam 10 continues compression of the torsion beam material W10 without transferring to another device, it is possible to improve the productivity.
[0147]
　Further, according to the torsion beam manufacturing apparatus 100C, since the second molding part 132B is moved in the arrow T132 direction by a hydraulic cylinder (shape-changing portion supporting member driving unit) 132C, the moving speed and the moving timing of the second molding portion 132B easy and it can be efficiently controlled.
[0148]

　Next, with reference to FIGS. 19 and 20, a description of a fifth embodiment of the present invention.
　Figure 19 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus 100D according to the present embodiment. Figure 20 (A) ~ FIG 20 (E) is a diagram illustrating a process of producing the torsion beam according to the present embodiment along the flow of FIG. 20 (A) ~ FIG 20 (E), E of FIG. 19 it is a view corresponding to part.
[0149]
　Referring to FIG 19, it will be described a schematic configuration of the torsion beam manufacturing apparatus 100D according to the present embodiment.
　The torsion beam manufacturing apparatus 100D includes a press forming fixed (mold) 110A, a pair of compression processing unit 120B, and the press molding movable die drive unit 130C, the control unit (not shown).
　In the torsion beam manufacturing apparatus 100D, a press molding fixed 110A and the press molding movable die drive unit 130C constitutes a press machine, the pair of compression processing unit 120B forms a compression machine.
　The configuration and operation of press-forming the fixed mold 110A is the same as the third embodiment, also, since the configuration and operation of the compression processing unit 120B is the same as in the fourth embodiment are denoted by the same reference numerals the duplicated description thereof is omitted.
[0150]
　Press molding movable die drive unit 130C includes a press-molding movable die (movable die) 133, and a hydraulic cylinder (second drive mechanism) 135 for advancing and retracting the press molding movable die 133 in the arrow T130 direction (elevation) there.
[0151]
　Press molding the movable mold 133, as shown in FIG. 19, a first molding part 133A, 2 one second mold part which are respectively disposed on both sides in the longitudinal direction of the first molding part 133A (shape-changing portion support member) 133B and It comprises a cam surface (cam mechanism) 133C, and spring 133D, the. The second molding portion 133B may be further provided with a guide member for guiding the movement in the horizontal direction with respect to the first mold portion 133A.
　Further, on the lower surface of the press-molding movable die 133, it is formed shape corresponding to the upper shape of the torsion beam material W10, press molding the torsion beam material W10 in cooperation with the press molding fixed 110A. Incidentally, the lower surface shape of the press-molding movable die 133 are the substantially same as the lower surface shape of the press-molding movable die 131 described in the third embodiment, a description thereof will be omitted. For example, the cross-sectional shape in the X7-X7 arrow view in FIG. 19 is the same as the sectional shape described in FIG. 15 of the third embodiment.
[0152]
　Cam surfaces 133C are formed on the inner surface of the second molding portion 133B, toward the lower surface of the first mold portion 133A, an inclined surface inclined so as to approach the side surface of the first mold portion 133A. The gap formed between the cam surfaces 133C and the opposing surface, which is tapered toward the pressing direction of the press-molding movable die 133.
[0153]
　Between the first mold portion 133A and the second forming unit 133B is by the spring 133D, in a state in which external force is not applied, is maintained so as to maintain a predetermined distance. If an external force is applied to the spring 133D, the cam surface 133C approaches the first molding part 133A side, constitute a cam mechanism that moves the second mold portion 133B in the longitudinal direction of the torsion beam material W10.
　Controller (not shown), the compression processing unit 120B and the press molding movable die drive unit 130C, directs the operation relating to pressing and compression process.
[0154]
　Referring to FIG. 20 (A) ~ FIG 20 (E), will be outlined in the torsion beam manufacturing process by torsion beam manufacturing apparatus 100D. Figure 20 (A) ~ FIG 20 (E) are views for explaining along the flow of the manufacturing steps of the torsion beam according to the fifth embodiment FIG. 20 (A) ~ FIG 20 (E), 19 it is a view corresponding to the E portion.
[0155]
(1) First, as shown in FIG. 20 (A), a metal material tube W0 placed on the press molding fixed 110A, moves the press-molding movable die 133 in the arrow T130F direction.
(2) As shown in FIG. 20 (B), by press molding using a press molding fixed 110A and a press molding movable die 133, torsion beam material W10 is molded.
(3) Next, as shown in FIG. 20 (C), to advance the shape-changing portion supporting the punch 122 in the arrow T120F direction.
(4) Then, as shown in FIG. 20 (D), further advances in the arrow T120F direction the shape changing portion supporting the punch 122.
　At this time, the spring 133D contracts, the second forming unit 133B is moved in the arrow T132F direction. As a result, to form a shape-changing portion supporting the punch 122 and the torsion beam 10 by compressing the torsion beam material W10 in the longitudinal direction while supporting the shape changing portion 12W by the second molding portion 133B. In this compression process, the torsion beam material W10, by giving more than 2.0% strain of 0.5% or more in its axial direction, without causing buckling, the tensile residual stress in the front and back surfaces in the thickness direction it becomes possible to release. In addition, the central portion 11W and the shape changing portion 12W respective outer surface wa of the torsion beam material W10, from the fact that over compression on supporting the wb, buckling does not easily occur.
(5) After forming the torsion beam 10, as shown in FIG. 20 (E), to increase the press-molding movable die 133 in the arrow T130R direction. Thus, by the restoring force of the spring 133D, the second mold is moved in the arrow T132R direction.
　Also, retracting the shape-changing portion supporting the punch 122 in the arrow T120R direction.
[0156]
　Torsion beam manufacturing method according to the fifth embodiment, according to the torsion beam manufacturing apparatus 100D, it is possible to manufacture the torsion beam 10 that is fatigue characteristics excellent efficiently.
[0157]
　Further, according to the torsion beam manufacturing apparatus 100D, since compressing the shape changing portion supporting the punch 122 and the torsion beam material W10 while holding the shape changing portion 12W by the second molding portion 133B in the longitudinal direction inwardly, the efficiency from the connection portion 12A it can be reduced or removed to residual stresses.
[0158]
　Further, according to the torsion beam manufacturing apparatus 100D, after forming the torsion beam material W10 metallic material tube W0 is pressed, it is possible to continue to compress the torsion beam material W10 without transferring to another device, in manufacturing the torsion beam 10 it is possible to improve the productivity.
[0159]

　Next, with reference to FIGS. 21 and 22, a description will be given of a sixth embodiment of the present invention. Figure 21 is a vertical sectional view will be described along the flow of the manufacturing process of the torsion beam according to the present embodiment (A) ~ (D). Further, FIG. 22 is a drawing showing the essential components of the torsion beam manufacturing apparatus according to this embodiment, is a longitudinal sectional view taken in the arrow X4-X4 in FIG. 21.
[0160]
　Figure 21 (A) corresponds to the preparation process shown in step S101 in FIG. 6. In this process, and straight along the central axis CL, the thickness is prepared a metal material tube SP (blank tube) is uniform circular steel tube. The opposite edges e1, e2 of the metallic material tube SP, when seen in longitudinal section including the rotational axis CL, which forms a perpendicular to the axis of rotation CL. It will be described later dashed CF.
[0161]
　Subsequent FIG. 21 (B) corresponds to the pressing step shown in step S102 in FIG. 6. In this step, the press machine (not shown), a metal material tube SP by pressing to obtain a torsion beam material W10 having a bottom eb and ears er. Bottom eb is, for example, a folded portion of the lowermost end of the second wall portion S120C shown in FIG. 5C, are formed so as to extend along the central axis line CL. Further, ears er is, for example, a pair of folded wall portions S130C shown in FIG. 5C, are formed so as to extend along the central axis line CL.
　During pressing, as shown in FIG. 21 (B), forms a recessed circular shape in bottom eb, it should warped so as to form ears er in a convex arc shape. Opposite edges e1, e2 at this time is to keep the perpendicular to the central axis CL, it becomes an inclined state with respect to the vertical direction. Therefore, both end edges e1 of the torsion beam material W10 ', e2' so that along the vertical direction, cut off surplus portions including both end edges e1, e2. In FIG. 21 (B), the show extra length portion cut off by the broken line. In this way, the torsion beam material W10 are obtained (corresponding to step S103 of FIG. 6).
[0162]
　Continued Figure 21 (C) and (D) corresponds to the compression processing step shown in step S104 in FIG. 6. In this step, by performing compression processing on torsion beam material W10, in the axial direction giving the 2.0% compressive strain of 0.5% or more. Thus, by releasing without the residual stress in the thickness direction of the front and back surfaces of the torsion beam material W10 buckling occurs, it is possible to obtain a torsion beam 10 (corresponding to step S105 of FIG. 6).
[0163]
　Compressive strain amount described above may be set based on the full length along the convex arc shape shown in FIG. 21 (B), the total length along the straight line shown in FIG. 21 (D). Specifically, for example, the amount of compressive strain at the position of the ear er epsilon (%) is the total length L1 (mm) along the convex circular arc shape shown in FIG. 21 (B), shown in FIG. 21 (D) by using the entire length along a straight line L2 (mm), ε = it can be calculated by ((L1-L2) / L1) × 100. Then, the epsilon is preferably satisfies 0.5 ≦ ε ≦ 2.0.
[0164]
　Torsion beam manufacturing apparatus used in this process, and the press machine for performing press working step shown in FIG. 21 (B), and a compression processing machine 200 to perform the steps shown in FIG. 21 (C) and (D) It is provided.
[0165]
　Compression processing machine 200 includes a fixed die 210 which recess 211 is formed, the movable die 220 to advance and retreat with respect to the recess 211 of the fixed mold 210, a driving unit for driving the movable die 220 (not shown), and a control unit (not shown).
　The recess 211 of the fixed mold 210 includes a bottom wall 211a having a shape that matches the bottom shape of the torsion beam 10, and a pair of side wall surfaces 211b having a shape that matches the side shape of the torsion beam 10, both edges e1 of the torsion beam 10 ' It is partitioned and formed by a pair of end wall 211c opposite to e2 '. As shown in FIG. 21 (D), the spacing between the pair of end walls 211c, is set to be equal to the length of the torsion beam 10 to be manufactured. Further, each end wall 211c, respectively, perpendicular to the central axis line CL of the torsion beam 10. Furthermore, the bottom wall 211a, stamped pin (not shown) are provided a plurality of, to discharge the torsion beam 10 after molding the outer recess 211.
[0166]
　As shown in FIG. 22, the recess 211 is a longitudinal cross-sectional shape in the central portion in the longitudinal direction has a substantially V-shaped or substantially U-shaped. The longitudinal section is consistent with the longitudinal sectional shape of the central portion 11W and the shape changing portion 12W of the torsion beam material W10. More specifically, longitudinal sectional shape of the pair of side wall surfaces 211b is the central portion 11W and the shape changing portion 12W respective outer surface wa, coincides with longitudinal section of wb. Outer surface wa, wb, in the step of FIG. 21 which compresses (C), are spaced above them to a pair of side wall surfaces 211b.
　On the other hand, the recess 211 is a longitudinal cross-sectional shape in both end portions in the longitudinal direction forms a semi-circular. The longitudinal section is consistent with the longitudinal sectional shape of the mounting closed-section portion 13W of the torsion beam material W10.
[0167]
　As shown in FIG. 22, the lower surface 220a of the movable die 220 has a convex cross-section of substantially V-shaped or substantially U-shaped at the position corresponding to the central portion 11W and the shape changing portion 12W. The lower surface 220a, in the position corresponding to the mounting closed cross-section portion 13W has a concave semicircular cross section. The lower surface 220a is at the stage of FIG. 21 (C) for starting the compression, except the longitudinally middle position is spaced upward with respect to the pair of side wall surfaces 211b.
[0168]
　In the above compression processing step using a compression machine 200 description, first, as shown in FIG. 21 (C), the torsion beam material W10, so that the bottom eb is the ear er in vertically downward directed vertically upward , arranged in the recess 211. Each end edge e1 of the thus arranged torsion beam material W10 ', e2', respectively, facing the end wall 211c.
　After placing the torsion beam material W10, the driving unit for instructing received from the control unit, as shown in FIG. 21 (D), is pushed into the recess 211 of the movable die 220 to its bottom dead center position . Then, the torsion beam material W10 is subjected to pressing force by the movable mold 220 in ears er side will be deformed in a direction to reduce its warpage. That is, the torsion beam material W10 to the center axis CL is warped to form a gentle arc by pressing, the central axis line CL to obtain a torsion beam 10 that forms a straight line.
[0169]
　During this pressing, both edges e1 of the torsion beam material W10 ', e2' is the distance between, is kept constant to be equal to the spacing of a pair of end wall 211c. Therefore, as the total length along the curved shape is reduced gradually, with respect to the torsion beam material W10, compressive force is applied along the central axis line CL. This compressive force is applied in the vertical direction the entire range of over the ears er from the bottom eb, as illustrated in FIG. 21 (B), min obtained by cutting off the previously diagonally opposite edges e1, e2, better bottom eb slightly larger than ear er, the amount of compression is increased. As a result, towards the bottom eb is slightly larger than the ear portion er, the compression ratio is high.
[0170]
　As described above, it is possible to apply a compressive strain caused by compression forces warped in the axial direction with respect to the torsion beam material W10. Moreover, in the present embodiment, when comparing the portion along the part and the ear part er along the bottom eb, when the cut off end in FIG. 21 (B), the bottom eb side of the ears er side minute have left the longer the better of, it is possible to further increase meat and more to increase the compression ratio of the bottom eb side. Thus, according to this embodiment, the residual stress is totally thickened and are reduced or eliminated, yet, it is possible to obtain a torsion beam 10 in which the bottom eb side thicker than the ears er .
[0171]
　In the present embodiment, after the pressing step shown in FIG. 21 (B), has been cut off both edges e1, e2 obliquely, not limited to this embodiment. For example, as shown in FIG. 21 (A), at the time of stamping before the metal material pipe SP, the broken line CF in advance by cutting off a portion including both edges e1, e2 obliquely, followed by performing press working steps it may be. Again, both edges e1 ', e2' can be obtained torsion beam material W10 with.
[0172]
　Hereinafter, summarized gist of the present embodiment.
　The torsion beam manufacturing method of this embodiment, as shown in FIG. 21 (A) and (B), prior to the compression step, the connecting portion 12A along the entire length including the (connection area), along the longitudinal direction having a preparation step of preparing a torsion beam material W10 with the warp. Moreover, in the preparation step, both end edges e1 ', e2' are prepared torsion beam material W10 inclined with respect to the longitudinal direction.
　Then, as shown in FIG. 21 (C) and (D), in the compression process, both edges e1 of the torsion beam material W10 ', e2' while restricting the elongation of the linear distance between, pressure to reduce the warpage give to the torsion beam material W10. This compression process, the torsion beam material W10, over the entire length including the connection portion 12A (connection region), imparting a distortion amount of 2.0% or less than 0.5% in the longitudinal direction.
[0173]
　Compression processing machine 200 of the present embodiment (torsion beam manufacturing apparatus), and the central portion 11 in cross section is a closed section of the substantially V-shaped or substantially U-shaped at any position in the longitudinal direction perpendicular to the longitudinal direction, a shape changing portion 12 having the connecting portion 12A having a continuous to the central portion 11 and closed section of a different shape as the closed section (connection area), to produce a torsion beam 10 having a.
　Then, the compression processing machine 200, and has a central portion 11 and a shape changing part 12, over the entire length including the connection portion 12A (connection area), torsion beam material with warp along the longitudinal direction fixed mold 210 having a recess 211 for receiving a W10 (first mold), the movable die 220 approaches from a direction to reduce the warpage against torsion beam disposed in the recess 211 material W10 (second mold) When provided with the drive unit for relatively close between them fixed mold 210 and movable mold 220 and the (fourth driving mechanism), the.
　The recess 211, end edges e1 of the torsion beam material W10 ', e2' has a pair of end wall 211c opposite to the (elongation regulating surface). Then, the distance between the pair of end walls 211c (total length L2) is shorter than the total length L1 of the curve along the warp of the torsion beam material W10.
[0174]

　Next, with reference to FIGS. 23 and 24, a description will be given of a seventh embodiment of the present invention. Figure 23 is a vertical sectional view will be described along the flow of the manufacturing process of the torsion beam according to the present embodiment (A) ~ (D). Further, FIG. 24 is a view showing a torsion beam manufacturing apparatus according to this embodiment, is a longitudinal sectional view taken in the arrow X5-X5 in FIG. 23 (C).
　This embodiment, in order to correspond to a modification of the sixth embodiment, in the following description, particularly focuses on the differences from the sixth embodiment, other components are the same as the sixth embodiment the description thereof is omitted as.
[0175]
　In FIG. 23 (A), similarly to FIG. 21 (A), the preparing a metal material tube SP. It will be described later dashed CF.
　Subsequent FIG. 23 (B) corresponds to the pressing step shown in step S102 in FIG. 6. In this step, the press machine (not shown), a metal material tube SP by pressing to obtain a torsion beam material W10 having a bottom eb and ears er. At this time of pressing, as shown in FIG. 23 (B), a convex arc shape in the bottom eb, should warped so as to form a recessed circular shape in ear er. Opposite edges e1, e2 at this time is to keep the perpendicular to the central axis CL, it becomes an inclined state with respect to the vertical direction. Therefore, both end edges e1 of the torsion beam material W10 ', e2' so that along the vertical direction, cut off surplus portions including both end edges e1, e2. In FIG. 23 (B), shows the excess length portion cut off by the broken line. In this way, the torsion beam material W10 are obtained (corresponding to step S103 of FIG. 6).
[0176]
　Continued Figure 23 (C) and (D) corresponds to the compression processing step shown in step S104 in FIG. 6. In this step, by performing compression processing on torsion beam material W10, in the axial direction giving the 2.0% compressive strain of 0.5% or more. Thus, the residual stress in the thickness direction of the front and back surfaces of the torsion beam material W10, to release without causing buckling, it can be obtained torsion beam 10 (corresponding to step S105 of FIG. 6).
[0177]
　Compressive strain amount described above may be set based on the full length along the convex arc shape shown in FIG. 23 (B), the total length along the straight line shown in FIG. 23 (D). Specifically, for example, the amount of compressive strain at the position of the ear er epsilon (%) is the total length L1 (mm) along the convex circular arc shape shown in FIG. 23 (B), shown in FIG. 23 (D) by using the entire length along a straight line L2 (mm), ε = it can be calculated by ((L1-L2) / L1) × 100. Then, the epsilon is preferably satisfies 0.5 ≦ ε ≦ 2.0.
[0178]
　Torsion beam manufacturing apparatus used in this process, and the press machine for performing press working process shown in FIG. 23 (B), and a compression processing machine 300 to perform the steps shown in FIG. 23 (C) and (D) It is provided.
[0179]
　Compression processing machine 300 includes a fixed 310 recess 311 is formed, the movable die 320 to advance and retreat with respect to the recess 311 of the fixed mold 310, a driving unit for driving the movable die 320 (not shown), and a control unit (not shown).
　Recess 311 of the fixed mold 310 includes a bottom wall 311a having the shape conforming to the shape of the ear portion er of the torsion beam 10, and a pair of side wall surfaces 311b having a shape that matches the side shape of the torsion beam 10, both ends of the torsion beam 10 edge e1 ', e2' are defined and formed by a pair of end wall 311c opposite to. As shown in FIG. 23 (D), the spacing between the pair of end walls 311 c, are set to be equal to the length of the torsion beam 10 to be manufactured. Further, each end wall 311c, respectively, perpendicular to the central axis line CL of the torsion beam 10. Furthermore, the bottom wall 311a, stamped pin (not shown) are provided a plurality of, to discharge the torsion beam 10 after molding the outer recess 311.
[0180]
　As shown in FIG. 24, the recess 311, the cross-sectional shape in the central portion in the longitudinal direction forms a generally inverted V-shaped or substantially inverted U-shape. The cross-sectional shape is consistent with the upper cross-sectional shape of the central portion 11W and the shape changing portion 12W of the torsion beam material W10.
　On the other hand, the recess 311, the cross-sectional shape in both end portions in the longitudinal direction forms a semi-circular. The cross-sectional shape is consistent with the cross-sectional shape of the mounting closed-section portion 13W of the torsion beam material W10.
[0181]
　As shown in FIG. 24, the lower surface 320a of the movable die 320, the cross-sectional shape in the central portion in the longitudinal direction forms a generally inverted V-shaped or substantially inverted U-shape. The cross-sectional shape is consistent with the lower cross-sectional shape of the central portion 11W and the shape changing portion 12W of the torsion beam material W10.
　On the other hand, the lower surface 320a is the cross-sectional shape in both end portions in the longitudinal direction forms a semi-circular. The cross-sectional shape is consistent with the cross-sectional shape of the mounting closed-section portion 13W of the torsion beam material W10.
[0182]
　In the above compression processing step using a compression machine 300 description, first, as shown in FIG. 23 (C), the torsion beam material W10, so that the bottom eb is the ear er a vertical upward directed vertically downward , arranged in the recess 211. Each end edge e1 of the thus arranged torsion beam material W10 ', e2', respectively, facing an end wall 311 c.
　After placing the torsion beam material W10, the drive unit which receives an instruction from the control unit, as shown in FIG. 23 (D), is pushed into the recess 311 of the movable die 320 to its bottom dead center position . Then, the torsion beam material W10 is subjected to pressing force by the movable mold 320, it will be deformed in a direction to reduce its warpage. That is, by pressing a torsion beam material W10 to the center axis CL is warped to form a gentle arc, the center axis CL to obtain the torsion beam 10 that forms a straight line.
[0183]
　During this pressing, both edges e1 of the torsion beam material W10 ', e2' is the distance between, is kept constant by a distance between a pair of end wall 311 c. Therefore, as the overall length is shortened gradually, the torsion beam material W10, compressive force is applied to warped in the axial direction. This compressive force is applied in the vertical direction the entire range of over the ears er from the bottom eb, as illustrated in FIG. 23 (B), minute to cut off in advance obliquely portion including both edges e1, e2, bottom eb towards the ears er than are slightly the amount of compression is increased. As a result, towards the ears er than the bottom eb is, slightly, the compression ratio is high.
[0184]
　As described above, it is possible to apply a compressive strain caused by compression forces warped in the axial direction with respect to the torsion beam material W10. Moreover, in the present embodiment, when comparing the portion along the part and the ear part er along the bottom eb, bottom when cutting off an end portion in FIG. 23 (B), towards the ear er side eb minute have left a little longer than the side, it is possible to further increase the meat to the compression ratio of the ears er side more to increase. Thus, according to this embodiment, the residual stress is reduced or removed by and overall thickening, moreover, as can be obtained torsion beam 10 that thicker ears er side than the bottom eb side there.
[0185]
　In the present embodiment, after the pressing step shown in FIG. 23 (B), has been cut off both edges e1, e2 obliquely, not limited to this embodiment. For example, as shown in FIG. 23 (A), at the time of stamping before the metal material pipe SP, the broken line CF in advance by cutting off a portion including both edges e1, e2 obliquely, followed by performing press working steps it may be. Again, both edges e1 ', e2' can be obtained torsion beam material W10 with.
[0186]

　Next, with reference to FIG. 25, will be described an eighth embodiment of the present invention. Figure 25 is a longitudinal sectional view illustrating a schematic configuration of a torsion beam manufacturing apparatus 400 according to this embodiment.
　The torsion beam manufacturing apparatus 400 includes a press forming fixed (mold) 410B, a pair of compression processing unit 420B, and the press molding movable die drive unit 430B, the control unit (not shown).
　In the torsion beam manufacturing apparatus 400, the press molding fixed 410B and the press molding movable die drive unit 430B constitute a press machine, the pair of compression processing unit 420B forms a compression machine.
[0187]
　Press forming fixed (mold) 410B, the recess is used to obtain the torsion beam material W10 metallic material tube W0 pressing to 410BU is formed. That is, the press-molding fixed 410B, recess 410BU having a shape corresponding to the lower surface of the torsion beam material W10 is formed faces upward. Since the detailed cross-sectional shape of the recess 410BU is the same as the recess 110AU described in the third embodiment, a description thereof will be omitted.
　Further, press forming fixed 410B, at the time of compression processing the torsion beam material W10 by a pair of compression processing unit 420B, also functions as a torsion beam material support table for supporting the torsion beam material W10.
[0188]
　Press molding movable die drive unit 430B includes press-forming the movable mold with (mold) 432, and a hydraulic cylinder (driving unit) 435 for advancing and retracting the press molding movable die 432 in the arrow T430 direction (elevation).
　The lower surface of the press-molding movable die 432, be formed shape corresponding to the upper shape of the torsion beam material W10, obtain torsion beam material W10 metallic material tube W0 pressing to cooperate with a press molding fixed 410B . Incidentally, the lower surface shape of the press-molding movable die 432 are the substantially same as the lower surface shape of the press-molding movable die 131 described in the third embodiment, a description thereof will be omitted. For example, the cross-sectional shape in the X7-X7 arrow view in FIG. 25 is the same as the sectional shape described in FIG. 15 of the third embodiment.
[0189]
　Each compression processing unit 420B, respectively, as shown in FIG. 25, advancing and retracting the shape changing portion supporting the punch (inner support member) 422, a shape change portion supporting the punch 422 in the arrow T420 direction along the longitudinal direction of the torsion beam material W10 and a hydraulic cylinder (not shown) to.
　Each shape-changing portion supporting the punch 422, respectively, are formed in a shape corresponding to the internal shape of the shape changing portion 12W and mounting the closed-section portion 13W. Each shape-changing portion supporting the punch 422, respectively, after obtaining the torsion beam material W10 metallic material tube W0 pressing to, pressed into each end of the torsion beam material W10, the respective end portions sandwiched from their inner . Wherein each hydraulic cylinder, respectively, according to an instruction from the control unit (not shown), advancing and retracting the shape-changing portion supporting the punch 422 in the arrow T420 direction.
　Wherein the control unit (not shown), for each compression processing unit 420B and the press molding movable die drive unit 430B, direct the operation relating to pressing and compression process.
[0190]
　Next, described below outline the torsion beam manufacturing process by torsion beam manufacturing apparatus 400.
(1) First, by placing the metal material tube W0 for press molding fixed 410B on, lowers the press molding movable die 432.
(2) Then, by sandwiching a metal material tube W0 between the press molding fixed 410B and the press molding movable die 432, torsion beam material W10 is press-formed. At this point, since the shape-changing portion 12W in the both sides thereof in the formation of the central portion 11W is pulled, the cross-sectional shape of the shape changing portion 12W is slightly thinner than the final shape.
[0191]
(3) Next, is pushed inside the shape change portion 12W is moved forward the shape changing portion supporting the punch 422. As a result, since the shape-changing portion supporting the punch 422 is pinched from the inside shape changing portion 12W of the torsion beam material W10, the sectional shape of the shape changing portion 12W is a final shape.
[0192]
(4) Further is pushed shape changing portion supporting the punch 422, engaged formed on its outer peripheral surface a step 422a is the mounting portion 14W of the torsion beam material W10, and compressed along the torsion beam material W10 in the longitudinal direction to.
　In this compression process, the torsion beam material W10, by giving more than 2.0% strain of 0.5% or more in its axial direction, without causing buckling, the tensile residual stress in the front and back surfaces in the thickness direction it becomes possible to release. In addition, it from even have to apply compression on supporting the central portion 11W and the shape changing portion 12W respective outer surface of the torsion beam material W10, buckling does not easily occur.
(5) After forming the torsion beam 10, to retract the shape-changing portion supporting the punch 422. Furthermore, press molding movable die 432 is raised.
[0193]
　Torsion beam manufacturing method according to the present embodiment, according to the torsion beam manufacturing apparatus 400, it is possible to manufacture the torsion beam 10 that is fatigue characteristics excellent efficiently.
　Further, according to the torsion beam manufacturing apparatus 400, after forming the torsion beam material W10 metallic material tube W0 pressing to, can be manufactured with torsion beam 10 continues compression of the torsion beam material W10 without transferring to another device, it is possible to improve the productivity.
[0194]
　Having described the embodiments of the present invention, the present invention is not intended to be limited only to the embodiments described above without departing from the scope and spirit of the present invention, it can make various changes is there.
[0195]
　For example, in the first embodiment, it has been described a case where the torsion beam manufacturing apparatus 100 compresses the torsion beam material W10 holds the mounting portion 14W vicinity of the attachment closed-section portion 13W by mounting closed-section portion holding member 121 in the longitudinal direction. However, not limited only to this embodiment, the structure of mounting the closed-section portion holding member 121, the position for holding the torsion beam material W10 can be arbitrarily set by the compressible range connection portion 12A.
[0196]
　In the embodiments described above, press-forming the movable mold (movable mold) 131, 132 and 133 has been described for the case of forward and backward by a hydraulic cylinder 135, for example, forward and backward by an actuator other than the crank mechanism or a hydraulic cylinder arrangement (not shown) may be employed.
[0197]
　Further, the first, in the third embodiment, the hydraulic cylinder (first driving mechanism) holding the mounting closed cross-section portion 13W torsion beam manufacturing apparatus 100,100B is by attaching the closed-section portion holding member 121 125 by a torsion beam element It has been described to compress the W10 in the longitudinal direction. However, not limited to this embodiment, the structure of mounting the closed-section portion holding member 121, the position for holding the mounting closed-section portion holding member 121, the configuration of the drive unit, setting the connection portion 12A to the compression if any it can.
[0198]
　Further, the second, in the fourth embodiment, the torsion beam manufacturing apparatus 100A, 100C is to retain the shape changing portion 12W by the second molding portion 132B, 133B and shape changing portion supporting the punch (inner support member) 122, torsion beam It has been described to compress the material W10 longitudinally. Further, the torsion beam manufacturing apparatus 100B is, to retain the shape changing portion 12W by a change in shape outer side holding member 1210 and the shape-changing portion supporting the punch (inner support member) 122, a case of compressing the torsion beam material W10 longitudinally explained. However, not limited only to these embodiments, the configuration of the holding member for holding the shape changing portion 12W, the position for holding the torsion beam material W10, the configuration of the drive unit, setting the connection portion 12A to the compression if any it can.
[0199]
　Further, in the second embodiment, the shape change outer side holding member 1210 has been described the case that includes an upper outer holding portion 1211 and the lower outer holding portion 1212, for example, elongated torsion beam material W10 it may be divided into three or more when viewed along the direction.
　Further, in the second embodiment, the case has been described where the shape change outer side holding member 1210 holds the shape changing portion 12W and attached closed cross-section portion 13W, compressed if the shape changing portion of the connection portion 12A 12W only may be held.
[0200]
　Further, in the second embodiment, the upper outer holding portion 1211, a lower outer holding portion 1212, the case of providing each and both of the shape changing portion 12W and attached closed-section portion 13W complementarily formed outer retention feature It was described. However, not limited to this embodiment, to the extent possible compressing the connecting portion 12A, a part of the outer shape of the shape changing portion 12W and attached closed-section portion 13W only may be complementarily formed, outer holding profile portion It can be arbitrarily set for.
[0201]
　Further, in the above-described fourth embodiment, the case has been described where the torsion beam manufacturing apparatus 100C has an actuator (shape change absorbing means) 113B, whether provided with the actuator 113B can be arbitrarily set. Further, the torsion beam manufacturing apparatus of another embodiment may comprise an actuator 113B.
[0202]
　Further, instead of the compression processing unit 120 of the first embodiment or the third embodiment may employ compression processing unit 120C shown in FIG. 26. In this case, it is possible to combine the above-described first embodiment except for the compression processing unit 120,120A or 120B to either of the configuration of the fifth embodiment and the compression processing unit 120C. In the following description, with reference to the configuration of the first embodiment.
　Hydraulic cylinder (first driving mechanism) 125, when receiving the instruction from the control unit (not shown), the mounting closed cross-section portion the pushing member 123, is moved forward and backward along the arrow T123. This makes it possible to compress in the longitudinal direction of the torsion beam material W10.
[0203]
　Mounting the closed-section portion pusher member 123, the surface in contact with the mounting portion 14W of the opposite ends of the torsion beam material W10, recesses (not shown) may be provided in accordance with the sectional shape of the mounting portion 14W. For example, if the cross-sectional shape like a circular pipe attachment portion 14W, may be provided with circular recesses slightly larger inner diameter than the outer diameter. This allows reliably hold the torsion beam material W10. Alternatively, if there is such a recess, a single mounting closed-section portion pusher member 123, it can also be associated to the torsion beam material W10 of various sizes.
[0204]
　Also, fixing the position of one of the pair of attaching the closed-section portion pusher member 123, by relatively approaching the other to the one, forms applying compression torsion beam material W10 can also be employed.
[0205]
　Such, by employing the mounting closed cross-section portion the pushing member 123 of a simple structure, it can be a torsion beam manufacturing apparatus 100 itself, a more inexpensive and simple structure.
[0206]
　The compression processing unit 120,120A or 120B of the fifth embodiment from the first embodiment is driven by a hydraulic cylinder (first driving mechanism) 125. However, instead of the hydraulic cylinder 125 may be employed a cam mechanism.
[0207]
　Figure 27 shows a schematic configuration of a compression processing unit 120D using a cam mechanism. Compression processing unit 120D includes a first cam 124A, a second cam 124B. By the second cam 124B moves up and down along the arrow T124B, the first cam 124A may be moved forward and backward along the arrow T124A.
　The advance and retreat of the first cam 124A, attached closed cross-section portion pushing surface 124C of the first cam 124A presses against the mounting portion 14W of the opposite ends of the torsion beam material W10, can be added to compressed torsion beam material W10.
[0208]
　Compression processing unit 120D illustrated in FIG. 27 can be used as the compression processing unit 120,120A or 120B of the fifth embodiment from the first embodiment.
[0209]
　In the present invention, the amount of distortion, the difference between the total length of the torsion beam after compression and the overall length of the torsion beam before compression, divided by the total length of the torsion beam material before compression, it can be defined as a value obtained by multiplying by 100 the result . For example, if the total length is 4mm compress the torsion beam material in the longitudinal direction on one side is 1000 mm, the distortion amount is 0.8%.
　It is preferable lower limit of the strain amount is 0.5%. Further, from the viewpoint of stable production, the lower limit of the strain amount is preferably 0.8%. On the other hand, the upper limit of the strain amount from the viewpoint of prevention of dimensional accuracy deterioration of buckling or wrinkles or the like, 2.0% is preferred. Further, from the viewpoint of stable production, it is more preferable upper limit of the strain amount of 1.7%.
[0210]
　The shape changing portion supporting the punch (inner support member) 122, the actuator 113B, is either to follow or to synchronize the mutual operation of the hydraulic cylinder (shape-changing portion supporting member driving unit) 132C, it can be arbitrarily set.
[0211]
　In the above embodiments, the description has been given of the case where the inner side of the first wall portion S110A constituting the central portion 11 and the closed section of the second wall portion S120 is formed in close contact, the first whether to close contact with the inner side of the wall portion S110A and the second wall portion S120 can be set arbitrarily.
[0212]
　In the embodiments described above, the torsion beam 10, the description has been given of the case is substantially V-shape is convex upward when mounted on the vehicle body, by applying the torsion beam having an approximately U-shape may be, it may be configured to protrude on the lower side of the vehicle body.
[0213]
　In the embodiments described above, a metal material tube W0 used for forming the torsion beam material W10 was described for the case where a uniform round steel pipe wall thickness. The metallic material tube W0 as (or metal material tube SP) is, for example, fatigue relieving thick shape corresponding portion is formed steel plate (metal material plate) and plastic working the welded pipe formed by press molding or roll forming the or a metal tube formed Te, extrusion molding, may be a metal tube formed by a pultrusion.
[0214]
　In the above embodiments, the metal material pipes used in the production of the torsion beam 10 has been described is a steel pipe may be a metal tube other than steel.
[0215]
　In the embodiments described above, as shown in FIG. 4, the shape of the attachment closed-section portion 13 has been described for the case where a straight longitudinally may be stepped shape. That is, for mounting closed cross-section portion 13, first forming a step, subsequently be adopted a modification in which applying a compressive force while sandwiching the step by shape change outer side holding member 1210.
[0216]
　Referring to the case of applying this modification with respect to the second embodiment, first, as shown in FIG. 28 (A), pushed shape changing unit support punch 122A (the inner support member) into the end of the torsion beam material W10 go in. Shape changing portion supporting the punch 122A has a relatively outer diameter dimension is smaller tip 122a1, relatively outer diameter dimension is large proximal portion 122a2, formed between these front end portion 122a1 and a proximal end 122a2 step and a part 122A3. Outer diameter of the tip 122A1 is one is insertable dimensions the mounting closed cross-section portion 13, the outer diameter of the base end portion 122A2 is made slightly larger than the inner diameter of the attachment closed-section portion 13.
[0217]
　For shape-changing portion supporting the punch 122A has such a stepped shape, when pushed against the mounting closed-section portion 13W as described above, a pipe end of the attachment closed-section portion 13W mounting portion 14W is, the step portion It is expanded by 122A3 and a proximal end 122a2. As a result, as shown in FIG. 28 (A), the outer diameter of the portion of the mounting portion 14W of the attachment closed-section portion 13W is larger than the other portion, the engaging portion st is formed.
　Subsequently, to sandwich the mounting closed-section portion 13 from above and below by the upper outer holding portion 1211 and the lower outer holding portion 1212. At that time, the upper outer holding portion 1211 and the lower outer holding portion 1212 is positioned in advance so as not to crush locking portion st.
[0218]
　Subsequently, as shown in FIG. 28 (B), an upper outer holding portion 1211 and the lower outer holding portion 1212 and the shape changing portion supporting the punch 122A, it is moved in synchronism toward the central portion 11W. Then, the locking portion st mounting portion upper contour holding portion 1211 and the lower outer holding portions 1212 each of the side end surface via the 14W 1211a, for locking the 1212a, reliably compressive forces due to the shape changing portion supporting the punch 122A it is possible to impart to at least the connection portion 12A of the torsion beam material W10.
[0219]
　More say, in the second embodiment, when compressing the torsion beam material W10, so that not slip relative to the torsion beam material W10, set to strengthen the holding force by the upper outer holding portion 1211 and the lower outer holding portion 1212 which was. Then, so as not to excessively deform even under the gripping force, the shape change portion supporting the punch 122 has been used in combination as a core. In contrast, in this modification, in order to compress the mounting closed cross-section portion 13W primarily by engagement rather than friction, ensures even in the relatively weak gripping force by the upper outer holding portion 1211 and the lower outer holding portion 1212 It is applying a compressive force to. Therefore, it is possible to omit the use of the upper outer holding portion 1211 and the lower outer holding portion 1212. The formation of the locking portion st may be carried out on the torsion beam manufacturing apparatus, or may be previously performed before placing the torsion beam manufacturing apparatus.
　In the above description, although the present modification has been described as applied to the second embodiment, it may also be applied to other embodiments as a matter of course.
[0220]
　In the third embodiment, when the compression processing unit 120 compresses the torsion beam material W10, returning the press molding movable die 131 to a standby position (upward). However, the shape changing portion 12W, between the first wall portion S110C and press molding movable die 131 of the shape-changing portion 12W is not completely adhered. Thus, it may be performed compression processing of FIG. 16 (C) ~ Figure 16 (E) while retaining the torsion beam material W10 by press molding movable die 131.
[0221]
　Further, the torsion beam manufacturing apparatus 100B of the third embodiment, instead of the compression processing unit 120 may be employed compression processing unit 120A or 120B in the first or fourth embodiment.
[0222]
　The gist of the present invention based on the embodiments described above are summarized below.
(1) torsion beam manufacturing method according to an embodiment of the present invention includes a central portion 11 in cross section is a closed section of the substantially V-shaped or substantially U-shaped at any position in the longitudinal direction perpendicular to the longitudinal direction, the central portion and wherein the closed section continuous to 11 is a method for producing a torsion beam 10 to a shape changing portion 12, with a with a connection portion 12A (connection region) having a closed cross section of different shapes. For example, as shown in FIG. 9 (A) ~ FIG 9 (E), for at least the connection portion 12A of the torsion beam material W10 central portion 11 and the shape-changing portion 12 is formed, along the longitudinal direction having a compression step of obtaining a torsion beam 10 by applying a compressive force.
　According to the torsion beam manufacturing method according to this embodiment, to apply a compressive force to at least the connecting portion 12A in the compression process, it is possible to reduce or eliminate the residual stress remaining.
　As a result, it is possible to produce an excellent torsion beam 10 on fatigue properties. Moreover, since it does not require post-heat treatment, it is possible to efficiently manufacture.
[0223]
(2) For example, as shown in FIG. 12 (A) ~ FIG 12 (D), wherein the compression step, the inner shape changing portion supporting the outer portion along the longitudinal direction than the connecting portion 12A punch 122 ( and is supported by the inner support member), the outside of the outer portion while sandwiched by the upper outer holding portion 1211 (the outer clamping member), a shape change portion supporting the punch 122 and the upper outer holding portion 1211 in the central portion 11W approach is moved in the direction, it may be added to the compressive force.
　In this case, in the compression process, in terms of supporting the inside of the outer portions of the torsion beam material W10 in shape changing portion supporting the punch 122, so to apply a compressive force clamping the outside of the outer portion by the upper outer holding portion 1211 it can provide easily compressive force while suppressing the deformation of Dosotokata portion.
[0224]
(3) For example, as shown in FIG. 12 (A) ~ FIG 12 (D), wherein the compression step, is supported by the lower outer holding portions 1212 outside the connection portion 12A (the outer support member), the shape changing portion the movement in the same direction of the support punch 122 and the upper outer holding portion 1211 and in synchronism, may be moved lower outer holding portion 1212.
　In this case, the lower outer holding portion 1212 to move in synchronism with the movement of the shape changing portion supporting the punch 122 and the upper outer holding unit 1211, do not inhibit deformation of the torsion beam material W10 associated with compression. Therefore, it is possible to impart surely compressive force to the torsion beam material W10, it can be reduced or removed reliably residual stress.
[0225]
(4) For example, as shown in FIG. 9 (A) ~ FIG 9 (E), in said compression step, by relatively approaching along across the torsion beam material W10 in the longitudinal direction, the compressive force it may be added over the entire length of said torsion beam material W10.
　In this case, for compressing the torsion beam material W10 longitudinally inwardly over its entire length, the residual stress without leakage can be reduced or removed.
[0226]
(5) As mentioned in the above embodiments, the at compression step, by applying at least strain of 2.0% or less than 0.5% in the longitudinal direction with respect to the connecting portion 12A of the torsion beam material W10 it may be.
　In this case, a sufficient compressive force to to remove or reduce the residual stress of the torsion beam material W10, it can be imparted without causing buckling.
[0227]
As shown in (6) for example, FIG. 16 (A) ~ FIG 16 (C), prior to the compression step includes a pressing step of obtaining a torsion beam material W10 metallic material tube W0 (the mother tube) by pressing it may be.
　In this case, at the time after the pressing step, there remains a residual stress torsion beam material W10, it can be followed by the compression step, to remove it.
[0228]
(7) As shown in FIG. 14 for example, the torsion beam manufacturing apparatus 100B according to one embodiment of the present invention, the closing of substantially V-shaped or substantially U-shaped cross section perpendicular to the longitudinal direction at any position in the longitudinal direction the central portion 11 is a cross-sectional, shape changing portion 12 having a connection portion 12A (connection area) with continuous to the central portion 11 and closed section of a different shape as the closed section, to produce a torsion beam 10 having a device it is. Of the central portion 11W and the shape changing portion 12W torsion beam is formed materials W10, a portion of the one longitudinal of the connection portion 12A (connection region) when viewed along the side of the torsion beam material W10, connected pair of compression processing unit 120 for holding the portion of on the other side of the part 12A (the holding mechanism); a hydraulic cylinder 125 for relatively close between each compression processing unit 120 (first driving mechanism); the provided.
　According to the torsion beam manufacturing apparatus 100B according to this embodiment, the pair of compression processing unit 120 and the hydraulic cylinder 125, by applying a compressive force in the longitudinal direction at least with respect to the connection section 12A (connection region) of the torsion beam material W10 , it is possible to reduce or eliminate the residual stress remaining in the torsion beam material W10.
　As a result, it is possible to produce an excellent torsion beam 10 on fatigue properties. Moreover, since it does not require post-heat treatment, it is possible to efficiently manufacture.
[0229]
(8), for example, as the torsion beam manufacturing apparatus 100B shown in FIG. 14, the compression processing unit 120 may hold both ends of the torsion beam material W10.
　In this case, to compress and hold the ends of the torsion beam material W10 by a pair of compression processing unit 120, it is possible to impart a compressive force over the entire length of the torsion beam material W10. Therefore, it is possible to reduce or remove residual stress without omission over the entire length of the torsion beam material W10.
[0230]
(9) For example, as the torsion beam manufacturing apparatus 100B shown in FIG. 14, the central portion 11W and the shape changing portion press-molding movable mold 131 having a shape corresponding to 12W and (movable mold); the torsion beam material W10 central portion 11W and to a metal material tube W0 (blank tube) before imparting the shape changing portion 12W, a hydraulic cylinder 135 for pressing the press-molding movable die 131 (second drive mechanism); it may further comprise a.
　In this case, the hydraulic cylinder 135 by pressing the press-molding movable die 131 to the metallic material tube W0, can be obtained torsion beam material W10 having a central portion 11W and the shape changing portion 12W.
[0231]
(10) For example, as the torsion beam manufacturing apparatus 100C shown in FIG. 17, at least one of the compression processing unit 120 (each holding mechanism), the shape changing portion supporting the punch 122 to be inserted into the inside of the shape-changing portion 12W ( inner support member) and; second molding portion 132B that sandwich the outer radius variations 12W (the outer clamping member); may be provided.
　In this case, in terms of supporting the inner radius variations 12W of the torsion beam material W10 in shape changing portion supporting the punch 122, it is possible applying a compressive force to the outer radius variations 12W sandwiching the second molding portion 132B it can provide easily compressive force while suppressing the deformation of the shape-changing portion 12W.
[0232]
(11) For example, as the torsion beam manufacturing apparatus 100C shown in FIG. 17 may be employed the following configuration: press-molding movable die 132 (movable mold) of a having a shape corresponding to at least the central portion 11W a first shaping unit 132A (movable mold body portion), and has a shape corresponding to at least the shape changing portion 12W, the second mold 132B (movable mold arranged to be movable relative to the first mold portion 132A a mold end portion), a hydraulic cylinder 132C (third drive mechanism) to approach the second mold 132B to the first mold portion 132A, with the; second mold 132B also serves as the outer clamping member .
　In this case, with respect to metal material pipes W0 (mother tube) which is pressed by the press-molding movable die 132, with giving a shape corresponding to at least the central portion 11W by first forming unit 132A, at least a shape change by the second mold 132B providing a shape corresponding to the section 12W. Such insert the shape-changing portion supporting the punch 122 and the inner side of the shape changing portion 12W of the torsion beam material W10 was obtained in, and in a state where the outer radius variations 12W is sandwiched by the second mold 132B, the torsion beam material W10 applying a compressive force. According to this configuration, since the second mold 132B also serves the outer clamping member, it may be added as it continues to compressive force without transferring the torsion beam material W10 to other devices.
[0233]
(12) For example, as the torsion beam manufacturing apparatus 100C shown in FIG. 17 may be employed the following configuration: a torsion beam press forming fixed 110B for supporting the material W10 (supporting die) further comprising a; press forming fixed mold 110B is, and a torsion beam material W10, and the first supporting portion 111B for supporting the portion including the central portion 11 (supporting mold main body), provided to be movable relative to the first support portion 111B, at least shape comprising a second support section 112B for supporting the changed portion 12W and (the supporting die end), the.
　In this case, when applying a compressive force to the torsion beam material W10, since the second support portion 112B is movable relative to the first support portion 111B, do not inhibit deformation of the torsion beam material W10 associated with compression. Therefore, it is possible to impart surely compressive force to the torsion beam material W10, it can be reduced or removed reliably residual stress.
[0234]
(13) In the above embodiments, may be employed the following configuration: further comprising a control unit for controlling the hydraulic cylinder 125; the control unit operates the hydraulic cylinder 125, at least the connection of the torsion beam material W10 the amount of strain of less than the 2.0% 0.5% or more in the longitudinal direction given to parts 12A.
　In this case, a sufficient compressive force to to remove or reduce the residual stress of the torsion beam material W10, it can be imparted without causing buckling.
Example
[0235]
　Are shown below, but examples relating torsion beam according to the present invention, that the invention is not limited to those examples is obvious.
[0236]
　In this embodiment, the residual stress at the point X of Figure 29 and measured. Figure 29 is a schematic diagram showing a cross-section of the connection portion 12A. X point in Fig. 29 is that in the opposite position on the back surface of the outer peripheral surface of the second wall portion side turning point b1 is (the surface of the hollow portion S150B side).
　High residual stress tends to occur at point X in Figure 29, it tends to cause a reduction in fatigue properties. Therefore, to assess the residual stress in this portion, it is possible to evaluate the fatigue characteristics of the torsion beam. Note that this site is the spring back after press molding, the tensile residual stress is generated.
[0237]
　Since X points difficult to direct the measured be inside of the torsion beam 10, the measurement of the residual stress is determined by the strain gauge affixed to the outer peripheral surface of the torsion beam 10. Specifically, paste the strain gauge (not shown) to the second wall portion folding point b1 in FIG. 29. Then, cut the measurement site comprising the second wall portion folding points b1 and X points from the torsion beam 10. As a result, the constraint measurement site had received from the surrounding is solved, causing slight deformation due to residual stress in the measurement site. Distortion amount due to the slight deformation is measured by the strain gauge, the residual stress is calculated from the distortion amount. The measured residual stress is a numerical value on the outer peripheral surface of the torsion beam 10 can be estimated residual stress in the X point from the measured residual stress. Further, by FEM simulation that simulates the deformation of the steel pipe, it can be calculated residual stress in the X point.
[0238]
　Figure 30, was examined residual stress reduction amount in the case of varying the amount of strain of the axial compression on the torsion beam material W10 at 0-4 percent (%), show the results of FEM simulation of the steel pipe. Incidentally, four lines shown in FIG. 30 shows the respective VO-VO of FIG 3, VA-VA in FIG. 4, VB-VB, the results at each position of the VC-VC. Residual stress reduction amount (%) is, for residual stress before axial compression was defined as the ratio of the difference of the residual stress in the longitudinal axial compression. For example, the residual stress of the front axial compression is 500 MPa, the residual stress after axial compression to 150 MPa, the residual stress reduction amount is 70%.
[0239]
　According to the results of FIG. 30, the distortion amount was observed peak between 0.5% to 2.0%. That is, the distortion amount is increased significantly the residual stress reduction amount to become 0.5% or more, and the distortion amount becomes settles to a constant value and more than 2.0%. Reason to fall after the distortion amount has reached the peak is because the buckling occurs in the torsion beam material W10 too much the axial pressing.
　From the above, for at least the connecting portion of the torsion beam material W10, by applying a strain of 2.0% or less of the strain of 0.5% or more in the longitudinal direction (%), the X point without causing buckling residual stresses were found to be able to reduce.
Industrial Applicability
[0240]
　According to the torsion beam manufacturing method and torsion beam manufacturing apparatus according to the present invention, it is possible to produce a torsion beam that has fatigue properties more excellent efficient, industrial applicability is great.
DESCRIPTION OF SYMBOLS
[0241]
　10 torsion beam
　11,11W central
　12,12W shape changing portion
　12A connecting portions (connecting
　region) 100, 100A, 100B, 100C, 100D torsion beam manufacturing apparatus
　110B press forming fixed (supporting
　mold) 111B first supporting portion (supporting metal type body
　portion) 112B second supporting portion (supporting mold
　end) 120, 120A, 120B, 120C compression unit (holding
　mechanism) 121B, 121C clamp member (holding portion)
　122 shape change portion supporting the punch (inner support member)
　125 hydraulic cylinder (first driving
　mechanism) 131, 132 and 133 press-molding movable die (movable
　die) first molding part 132A (movable mold body
　portion) 132B second molding part (outer clamping member, movable mold ends
　part) 133D spring
　135 hydraulic cylinder (second drive
　mechanism) 210, 310 first mold
　11,311 recess
　211c, 311 c end wall (elongation regulating
　surface) 220, 320 second mold
　The 1211 side shape retention portion (outer pinching
　member) at 1212 side profile holding portion (the outer support
　member) E1 ', E2' end Yuan
　W0 metal material tube (plain
　tube) W10 of SuitesーSilicone Newspaper nn Bldg one woods material
　wa, wb outer surface

WE claims

[Requested item 1]
　Having a central portion which is closed cross-section of substantially V-shaped or substantially U-shaped, the closed section of and the closed section continuous with the central portion is different shape cross section perpendicular to the longitudinal direction at any position in the longitudinal direction a method of manufacturing a torsion beam having a shape changing portion having a connection area,
　at least the connection region of the torsion beam material the central portion and the shape change portion is formed to, along the longitudinal direction was added a compressive force by thickening at least the connecting region, it has a compression step of obtaining the torsion beam
torsion beam manufacturing method characterized by.
[Requested item 2]
　Wherein the compression step, and supports the inner of the outer portion along the longitudinal direction than the connection region with the inner support member, in a state where the outside of the outer portion is sandwiched by the outer clamping member, said inner support the member and the outer clamping member is moved in a direction approaching to the central portion, applying said compressive force
torsion beam method according to claim 1, characterized in that.
[Requested item 3]
　In the compression step,
　　the outer connection region is supported by outer support member,
　　the inner support member and moved with and synchronously in the same direction of the outer clamping member, moving the outer support member
, characterized in that torsion beam method according to claim 2.
[Requested item 4]
　Wherein the compression step, the torsion beam material and across it to relatively approach each other along the longitudinal direction of applying said compressive force over the entire length of said torsion beam material
torsion beam production according to claim 1, characterized in that Method.
[Requested item 5]
　Wherein the compression step, the torsion beam applying at least the strain amount of 2.0% or less than 0.5% in the longitudinal direction with respect to the connection region of the material
according to claim 1 any one of 4, characterized in that torsion beam method according to claim.
[Requested item 6]
　Wherein prior to the compression step, the blank tube is pressed with a press to obtain the torsion beam material
torsion beam manufacturing method according to any one of claims 1 to 5, characterized in that.
[Requested item 7]
　Wherein prior to the compression step, further comprising a preparation step of preparing the torsion beam material with warp along the longitudinal direction at least in the longitudinal direction of the part,
　in the compression step, between both end edges of the torsion beam material while regulating growth, giving the pressure to reduce the warp to the torsion beam material
torsion beam method according to claim 1, characterized in that.
[Requested item 8]
　Wherein in the preparation step, said end edges preparing the torsion beam material which is inclined relative to the longitudinal
torsion beam method according to claim 7, characterized in that.
[Requested item 9]
　In the compression step, it imparts a distortion amount of 2.0% or less than 0.5% in the longitudinal direction at least with respect to the connection region of the torsion beam material
torsion beam according to claim 7 or 8, characterized in that Production method.
[Requested item 10]
　Wherein when applying the compressive force in the compression step, supporting at least the outer surface of the connection region
torsion beam method according to any one of claims 1 to 9, characterized in that.
[Requested item 11]
　Having a central portion which is closed cross-section of substantially V-shaped or substantially U-shaped, the closed section of a different shape as the continuous with the central portion and the closed section cross section perpendicular to the longitudinal direction at any position in the longitudinal direction an apparatus for manufacturing a torsion beam having a shape changing portion having a connection region,
　of the torsion beam material the central portion and the shape change portion is formed, when viewed along the longitudinal direction of the torsion beam material wherein a portion of the well one side from the connection region, a pair of holding mechanisms for holding the part on the other side than the connection area;
　a first driving mechanism between the respective holding mechanism is relatively close ;
comprising a
torsion beam manufacturing apparatus characterized by.
[Requested item 12]
　Each retaining mechanism holds the both ends of the torsion beam material
torsion beam manufacturing apparatus according to claim 11, characterized in that.
[Requested item 13]
　And the movable mold having a shape corresponding to the central portion and the shape-changing portion;
　to blank tube before applying the central portion and the radius variations in the torsion beam material, a second pressing said movable mold ; drive mechanism and
further comprising a
torsion beam manufacturing apparatus according to claim 12, characterized in that.
[Requested item 14]
　Wherein at least one of the holding mechanism,
　　and the inner support member to be inserted inside the shape-changing portion;
　　; and the outer clamping member for clamping the outside of the shape changing part
includes a
claim 11, characterized in that the torsion beam manufacturing apparatus according to.
[Requested item 15]
　And the movable mold having a shape corresponding to the central portion and the shape-changing portion;
　to blank tube before applying the central portion and the radius variations in the torsion beam material, a second pressing said movable mold ; drive mechanism and
further comprising a
torsion beam manufacturing apparatus according to claim 14, characterized in that.
[Requested item 16]
　The movable mold,
　　and the movable mold body having a shape corresponding to at least the central portion,
　　and has a shape corresponding to at least the shape changing portion, so as to move freely with respect to the movable mold body portion and the movable mold end portion provided,
　　the third drive mechanism relative to the movable mold body portion moves the movable mold ends,
provided with;
　the movable mold ends, said outer clamping member also it serves as a;
that torsion beam manufacturing apparatus according to claim 15, wherein.
[Requested item 17]
　; Said torsion beam further comprises a support die for supporting the material
　the support mold,
　　the torsion beam material, a support mold body portion that supports the portion including the central portion,
　　moves relative to the support mold body portion and it provided freely, and a supporting mold end portion for supporting at least the shape-changing portion;
that torsion beam manufacturing apparatus according to any one of claims 11 to 16, characterized in.
[Requested item 18]
　Further comprising a control unit for controlling said first driving mechanism;
　wherein the control unit, the first by operating the drive mechanism, 0.5% said longitudinal at least with respect to the connection region of the torsion beam material ; imparting strain of 2.0% or more
torsion beam manufacturing apparatus according to any one of claims 11 to 17, characterized in that.
[Requested item 19]
　Among the torsion beam material held by the pair of holding mechanisms, further comprising a support for supporting at least the outer surface of the connection region
torsion beam production according to any one of claims 11 to 18, characterized in that apparatus.
[Requested item 20]
　Having a central portion which is closed cross-section of substantially V-shaped or substantially U-shaped, the closed section of a different shape as the continuous with the central portion and the closed section cross section perpendicular to the longitudinal direction at any position in the longitudinal direction and shape change portion having a connection region, a device for producing a torsion beam with a
　portion of said central portion and and has the shape changing portion of at least the longitudinal direction of the warp along the longitudinal direction a first mold having a recess for receiving a torsion beam material having,
　a second mold approaching along a direction to reduce the warpage relative arranged the torsion beam material in said recess,
　said first die and a fourth drive mechanism that relatively close between said second mold
comprises a,
　the recess has a pair of stretch restricting surface facing the opposite ends of the torsion beam material, the pair of Shin The distance between the regulating surface is shorter than the total length along the warp of the torsion beam material
torsion beam manufacturing apparatus characterized by.