0001]The present invention relates to a front axle beam and a manufacturing method thereof.
BACKGROUND
[0002]Front axle beam (hereinafter may be referred to as "front axle") is primarily a vehicle (e.g. a truck or bus, etc. (however, two-wheeled vehicles are excluded)) front wheel mounted to support the vehicle body They are used to. The front axle, as a component for transmitting the load of the vehicle body to the left and right front wheels, and, as a structural safety components, is important. The front axle, by securing a front wheel of the steering performance while securing the wheel in position, responsible for the running stability. Further, during braking, the front axle is a transmission path for transmitting the braking forces of the wheels. In this way, the front axle, running property, a steering resistance, and strongly affect parts in braking performance. Since required high rigidity for the front axle, the front axle weight is greater. On the other hand, from the viewpoint of fuel efficiency, weight reduction of the front axle is required.
[0003]
　JP 2003-285771 (Patent Document 1) proposes a front axle which can reduce the aerodynamic resistance during vehicle travel. The invention described in Patent Document 1 is aimed at improving fuel economy by reducing the aerodynamic drag.
[0004]
　Also, it has been proposed also a method for manufacturing the front axle. JP 2009-106955 (Patent Document 2) discloses a manufacturing method of the axle beam with a pair of left and right spring seat. In this manufacturing method, press molding one of the spring seat in the first round of the pressing process, press-molding the other spring seat at the second pressing step.
[0005]
　One strategy lighter front axle, and to increase the rigidity of the front axle. If it is possible to increase the rigidity of the front axle, the same rigidity as the conventional, more or lighter front axle can be realized in a more compact front axle. Further, if it is possible to increase the rigidity of the front axle, with the same cross-sectional size and the same weight as the conventional products, the front axle is possible to improve the various properties concerned. Therefore, new technology that can increase the rigidity of the front axle is required.
[0006]
　In general, for the running stability of the vehicle, heavy object is disposed in a low position of the vehicle height direction of the vehicle. That is, the position of the engine mounted on the front axle is preferably mounted on a lower vehicle height direction position. Kingpin mounting portion is provided at both ends of the front axle. It is attached underbody parts to the front wheels of the vehicle. Kingpin is inserted into a front wheel of the undercarriage parts through the kingpin mounting portion from the vehicle height direction improves side connecting the front axle and the front wheels. The front wheel is pivoted a king pin in the axial turn off the steering of the vehicle by the configuration. Because of this configuration, as shown in FIG. 2, front axle, for example, vehicle-widthwise center is low in vehicle height direction, the vehicle width direction end portion is higher in the vehicle height direction, a bow shape. The front axle cross-section is in the H-type, but is not produced by the universal rolling machine as H-section steel. Because the arcuate shape is can not be molded by a universal rolling mill.
[0007]
　Normally, the front axle is produced by die forging. For forging, for example, as shown in Figure 5B, the angle Q for demolding, the draft of Q 'is required. Therefore, the shape of the front axle is limited. As a result, improvement of the rigidity of the front axle is limited.
[0008]
　On the other hand, around the front axle, the moving parts of the engine and steering are arranged densely. Therefore, the front axle, is also required to fit into tight spaces so as not to interfere with these peripheral parts. Therefore, its rigidity can be enhanced techniques without increasing the cross-sectional size of the front axle, in particular sought.
CITATION
Patent Document
[0009]
Patent Document 1: JP 2003-285771 Patent Publication
Patent Document 2: JP 2009-106955 JP
Summary of the Invention
Problems that the Invention is to Solve
[0010]
　In such circumstances, one object of the present invention, the front axle beam capable of increasing its rigidity, and to provide its manufacturing method.
Means for Solving the Problems
[0011]
　Manufacturing method according to an embodiment of the present invention includes a web portion, a manufacturing method of the front axle beam with a beam portion of the H-shaped cross-section of which comprises a flange portion which is joined to the opposite ends of the web portion. Manufacturing method, in the cross-section, housing the flange portion to the mold, forging across a die in the extending direction of the flange portion. Further, in the cross section by pressing the tip of the flange portion in a direction orthogonal to the extending direction of the web portion bending the tip outwardly extending direction of the web portion.
[0012]
　Front axle beam according to an embodiment of the present invention includes a web portion, a front axle beam with a beam portion of the H-shaped cross-section of which comprises a flange portion which is joined to the opposite ends of the web portion. Flange portion, in the cross section, comprises a curved portion that the center line of the thickness of the flange portion is bent in the extending outwardly of the web portion.
The invention's effect
[0013]
　According to the present invention, the front axle beam is obtained with high rigidity. According to the production method of the present invention can be easily produced the front axle beam.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014]
[1] Figure 1 is a perspective view schematically showing an example of a front axle of the first embodiment.
FIG. 2 is a diagram showing the front of the front axle as shown in FIG. 1 schematically.
FIG. 3 is a diagram showing the upper surface of the front axle as shown in FIG. 1 schematically.
[4] FIG. 4 is a diagram showing a cross section of the front axle as shown in FIG. 1 schematically.
[Figure 5A] Figure 5A is produced by the production method of the second embodiment is a perspective view schematically showing a part of an example of a forged product after burr punching process.
[Figure 5B] Figure 5B is a diagram illustrating the forging of the cross section shown in FIG. 5A schematically.
[Figure 6A] Figure 6A is a cross-sectional view schematically showing a state before deformation starting An example of the second step.
[Figure 6B] Figure 6B is a cross-sectional view showing a state during deformation completion schematically an example shown in FIG. 6A.
[Figure 7A] Figure 7A is a cross-sectional view schematically showing a state before deformation starting An example of the third step.
[Figure 7B] Figure 7B is a cross-sectional view showing a state during deformation completion schematically an example shown in FIG. 7A.
[8] FIG. 8 is a graph showing changes in the contour of the cross section of the forging before and after the bending process (second and third steps).
FIG 9A] FIG 9A is a sectional view schematically showing a state before deformation starting different example of the second step.
[FIG. 9B] FIG 9B is a sectional view showing a state during deformation completion schematically an example shown in Figure 9A.
FIG 10A] FIG 10A is a cross-sectional view schematically showing a state before deformation starting different example of the third step.
[FIG. 10B] FIG 10B is a cross-sectional view showing a state during deformation completion schematically an example shown in FIG. 10A.
FIG 11A] FIG 11A is a cross-sectional view schematically showing a state before the start of deformation on other one of the third step.
FIG 11B] FIG 11B is a cross-sectional view showing a state during deformation completion schematically an example shown in FIG. 11A.
[12] FIG 12 is a diagram showing a sectional shape of the sample which is assumed in the examples.
[13] FIG 13 is a diagram showing a method of testing assumed in the examples.
FIG. 14 is a cross-section of the front axle of this embodiment is a diagram schematically illustrating.
DESCRIPTION OF THE INVENTION
[0015]
　As a result of intensive studies, the present inventors have found that to improve the rigidity of the front axle by devising the sectional shape of the front axle. In addition, it was found also method of manufacturing a highly rigid front axle. The present invention is based on this new finding.
[0016]
　Manufacturing method according to an embodiment of the present invention includes a web portion, a manufacturing method of the front axle beam with a beam portion of the H-shaped cross-section of which comprises a flange portion which is joined to the opposite ends of the web portion. Manufacturing method, in the cross-section, housing the flange portion to the mold, forging across a die in the extending direction of the flange portion. Further, in the cross section by pressing the tip of the flange portion in a direction orthogonal to the extending direction of the web portion bending the tip outwardly extending direction of the web portion.
[0017]
　In the above manufacturing method, putting a convex mold toward the web portion between the opposed flange portions, bending the tip on the outer side of the extending direction of the web portion, it is preferable.
[0018]
　In the above manufacturing method, furthermore, in the transverse section, the tip bent, while constrained from the outside in a direction perpendicular to the extending direction of the web portion, pushing from the outside in the extending direction of the web portion, it is preferable. In this case, in the cross section, the maximum width in the extending direction of the web portion of the front axle beam is the width of a portion of the web portion, it is preferable.
[0019]
　In the above manufacturing method, convex mold has a protrusion protruding toward the web portion, and a surface adjacent to the convex portion, the in cross-section, the surface web portion extending outwardly about the web portion away from, it is preferable.
[0020]
　In the above manufacturing method, the tip bent, placed in a recess of the concave mold having a recess, pressing from the outside in the extending direction of the web portion, it is preferable.
[0021]
　Front axle beam according to an embodiment of the present invention includes a web portion, a front axle beam with a beam portion of the H-shaped cross-section of which comprises a flange portion which is joined to the opposite ends of the web portion. Flange portion, in the cross section, comprises a curved portion that the center line of the thickness of the flange portion is bent in the extending outwardly of the web portion.
[0022]
　Further, in another aspect, the manufacturing method according to an embodiment of the present invention is the beam part and the method for producing a front axle beam and two kingpin mounting portions provided respectively on both longitudinal ends of the beam portions . Beam portion includes a web portion extending in the longitudinal direction, and four flange portions projecting forwardly and rearwardly from the respective upper and lower ends of the web portion.
　Manufacturing method,
　a rough web portion comprising a web portion, forging a comprising four coarse flanges top and from the respective lower ends of the shaped plate projecting towards the front and rear of the crude web portion, using a mold a first step of forming by forging steel Te,
　by at least one first mold, by pressing at least one specific rough flange portion of the four crude flanges, vertical outer forgings a second step of forming on the particular crude flange portion of the first bending portion that is bent toward,
　the inwardly in the vertical direction by pushing the end of the first bent portion by at least one second mold by deforming the end portion, and a third step of forming a second bend to a specific crude flange portion, in this order. In the third step, deforming the end portion while restraining the deformation in the longitudinal direction of said end portion.
[0023]
　In the above manufacturing method, in the third step, also deforming the end portion to a position that does not protrude outside the vertical direction than a portion other than the end portion, it is preferable.
[0024]
　In the above manufacturing method, the second mold includes a first surface for pushing against the end portion on the inner, and a second surface for restraining the deformation in the longitudinal direction of the end, it is preferable.
[0025]
　In the above manufacturing method, at least one specific rough flange portion may include a first and second specific rough flange are aligned in the vertical direction. The first mold includes a first inclined surface, the angle formed between the first inclined surface may comprise a 180 ° greater than the second slope. In this case, the second step, the first inclined surface of the first mold press first specific rough flange, and the line by the second inclined surface of the first mold press the second specific crude flange it may be cracking. Further in this case, the third step may be performed in two second mold disposed in the vertical direction so as to sandwich the forging.
[0026]
　In this manufacturing method, four rough flange portion includes first and second specific crude flange portion may be made of two normal rough flange not certain rough flange. In this case, it may be performed second step in two states usually the crude flange portion fixed. In the third step, the second mold with pressing the edge portion of the first bend, may limit the displacement of the normal crude flange portion by pressing the normal crude flange portion.
[0027]
　In the above manufacturing method, at least one specific rough flange, made of first and second specific crude flange portion, and the third and fourth particular crude flange are aligned in the vertical direction it may be. In this case, the second step, at the same time the first and second specific crude flange pressed by one of the first slope and the second slope of the first mold, the first to third specific rough flange portion of the other press the first inclined surface of the mold, and may be carried out by pressing by the second inclined surface of the fourth first mold certain crude flange portion of the other.
[0028]
　In the above manufacturing method, the second step may be performed in a state sandwiched by the two third mold forgings from the vertical direction. In the above manufacturing method, the third step, the rough web portion of the forged product may be performed in a state sandwiched by the two fourth die from the front and rear direction.
[0029]
　Further, in another aspect, the front axle beam, according to an embodiment of the present invention is a front axle beam comprising a beam portion, and two kingpin mounting portions provided respectively on both longitudinal ends of the beam portions. Beam portion includes a web portion extending in the longitudinal direction, and four flange portions projecting forwardly and rearwardly from the respective upper and lower ends of the web portion. At least one of the four flange portions is a specific flange portion including the bend portion. Vertical outer surfaces of the front axle beam of the bending portion of the surface is inclined toward the outside in the vertical direction after inclined toward the inside of the vertical direction as the distance from the web portion.
[0030]
　For the front axle, the ends of the bent portion may not protrude outside the upper and lower direction than a portion other than the end portion.
[0031]
　Hereinafter, embodiments of the present invention will be described by way of example. The present invention is not limited to the examples described below.
[0032]
　In this specification, when referring to the direction of the members constituting the front axle and which, unless otherwise stated, it refers to a direction in a state of arranging the front axle in the direction of use. For example, the term vertical direction of the front axle, unless otherwise stated, refers to a vertical direction in a state of arranging the front axle in the direction of use. That is, the up and down direction, which is the vehicle height direction of the front axle. Similarly, the horizontal and longitudinal directions, means a direction in a state of arranging the front axle in the direction of use. That is, the horizontal direction is a vehicle width direction of the front axle. The front-rear direction, which is the vehicle length direction of the front axle. Here, the front axle is provided with a beam portion having a H-shaped cross section of the beam portion comprises a plate-shaped web portion, and four plate-like flange portion protruding from both ends of the web portion. When placing the front axle in the direction of use, the beam portion is disposed in a horizontal direction. Furthermore, in cross-section of the front axle, the web portion extends in the vertical direction, the four flange portions projecting in the front-rear direction. Therefore, in the transverse plane of the front axle, the vertical direction is the same direction as the extending direction of the web portion, the front-rear direction is the same direction as the direction orthogonal to the extending direction of the web portion. Incidentally, the front and rear of the front axle, respectively, a front axle means in the same direction as the front and rear of the vehicle to be located. However, if the front axle is in the form of a symmetrical before and after the one direction and the front to the other direction as the rear. Further, when the direction of the member refers constituting intermediate product (such as forging) and it in the production of the front axle, unless otherwise stated, means the same direction as the front axle is a finished product.
[0033]
　(Manufacturing method of the front axle beam)
　the production method of the present embodiment, the beam portion and the method for producing a front axle and two kingpin mounting portions provided respectively on both longitudinal ends of the beam portion (front axle beam) it is. Beam portion includes a web portion extending in the longitudinal direction, and four flange portions projecting forwardly and rearwardly from the respective upper and lower ends of the web portion. That is, the manufacturing method of this embodiment includes a web portion, in the manufacturing method of the front axle (front axle beam) with a beam portion of H-shaped cross-section of which comprises a flange portion which is joined to the opposite ends of the web portion, the is there. In the present disclosure, means that simply integrated in the bonding, does not necessarily mean that joining by means of welding or fastening.
[0034]
　This manufacturing method includes a first and second steps described below. This manufacturing method includes a first, second, and third steps described below in this order.
[0035]
　The first step is a step of forming a forged product by forging a steel material with a mold (die forging step). The forging includes a coarse web portion comprising a web portion, and four rough flange plate of the respective upper and lower ends protruding toward the front and rear of the coarse web portion. Four of the crude flange portion is a portion to be a four flange portions of the front axle. Forged product obtained in the first step, such as those shown in Figure 5B.
[0036]
　That is, in the manufacturing method of this embodiment, the flange portion (crude flange portion) is housed in the mold, forging across a die in the extending direction of the flange portion.
[0037]
　Forgings, containing the crude beam portion comprising a beam unit. Hereinafter, the longitudinal direction of the beam portion and the coarse beam portion, sometimes referred to as "longitudinal direction LD". Further, the front-rear direction of the front axle and forgings called "front-rear direction HD", their vertical may be referred to as "vertical direction VD."
[0038]
　Usually, the forged product obtained in the first step burr is formed. Therefore, between the first step and the second step may be carried out burr punching process. There is no limitation on the burr punching process may be applied to known methods. When performing burr punching process, forgings burr has been removed, is subjected to a second step.
[0039]
　The second step, by at least one first mold, by pressing at least one specific rough flange portion of the four crude flange portion is bent outwardly in the vertical direction VD forgings first bend of the (e.g. 232a in FIG. 7A) is a step of forming a specific rough flange. A molded article obtained in the second step, such as those shown in Figure 6B.
[0040]
　That is, in the manufacturing method of this embodiment, the flange portion by pressing the tip of the (specific rough flange portion) in the direction perpendicular to the extending direction of the web portion (coarse web portion), the web portion and the distal end (crude web portion) bend outward in the extending direction of the.
[0041]
　In this specification, when referred to the inner and outer the flanges (or coarse flange portion), unless contrary to the context, the inside of the front axle or forging in the vertical direction VD (the extending direction of the web portion in cross section) and it refers to the outside. If the flange portion projecting from the upper end of the web portion (or coarse web portion) (or coarse flange portion), the inner direction means downward, the outer direction means upward. If the flange portion projecting from the lower end of the web portion (or coarse web portion) (or coarse flange portion), the inner direction means upwards, the outward direction refers to lower.
[0042]
　According to the manufacturing method of the front axle including a first and second steps described above, the cross section of the front axle, the center line of the thickness of the flange portion (specific flange portion) is bent in the extending outwardly of the web portion ( curved to) it can form a flange portion having a curved portion.
[0043]
　Usually, the first mold is disposed in the longitudinal direction HD forging, at least one first mold is moved back and forth direction HD forging. In the second step, usually, one or two first mold is used.
[0044]
　Four at least one of the rough flange (one, two, three, or four) is a specific rough flange. From the viewpoint of production process, it is preferable to bend the two coarse flange are arranged at the same time. Therefore, in a preferred example, a two or four of the particular crude flange portion of the four crude flange portion.
[0045]
　The third step, by deforming the end portion toward the inside of the vertical direction VD by pushing the end of the first bent portion by at least one second mold, the second bending section (e.g. FIG. 7B 232b) it is a step of forming on the particular crude flange portion. A molded article obtained in the third step, such as those shown in Figure 7B.
[0046]
　Usually, the second mold is disposed in a vertical direction VD forging, at least one second mold is moved in the vertical direction VD forging. In the third step, usually, one or two second mold is used.
[0047]
　In the third step, to deform the end portion in a state of restraining the deformation in the longitudinal direction HD of the end of the first bend. According to this configuration, while suppressing that the end of the first bend portion extends in the longitudinal direction HD, it can be deformed the end on the inner side of the vertical direction VD.
[0048]
　That is, in the manufacturing method of this embodiment, while a flange portion bent outward tip of (certain rough flange portion), and restrained from outward in a direction perpendicular to the extending direction of the web portion, extending in the web portion of the tip push from the outside to the extending direction.
[0049]
　First, according to the manufacturing method of the front axle including a second and third step, to form a second curved portion having a specific shape. Specifically, the outer surface of the vertical direction VD can be formed a second bent portion which is inclined toward the outside after inclined inward as the distance from the web portion.
[0050]
　The second bend portion may be formed over the entire longitudinal direction LD of the coarse beam portion may be formed only on a part of the longitudinal direction LD of the coarse beam portion. Normally, the front axle has two spring mounting seat. The second bend portion may be formed on all or part of the region between the two spring mounting seat thereof. The first bend is formed at a position corresponding to a position where the second bend is formed.
[0051]
　Usually, the shaping step is carried out after the third step. The shaping step, the shape of the predetermined portion (e.g., a spring mounting seat) is trimmed. Simultaneously with the third step may be carried out shaping step. That is, the shaping of the portion other than the first bending portion may be performed during the third step. In this case, second mold may also serve as a mold shaping process.
[0052]
　In the third step, may be deformed said end portion to a position that does not protrude outwardly in the vertical direction VD than a portion other than the end portion of the first bend. According to this configuration, it is possible to produce the front axle high rigidity without increasing the cross-sectional size. In an example of the third step, as than a portion other than the end portion located inside the vertical direction VD, may be deformed ends. In this case, the maximum width in the extending direction of the web portion of the front axle is the width of a portion of the web portion.
[0053]
　The second mold may comprise a first surface and a second surface. The first surface is a surface for pushing against the end of the first bend to the inside of the vertical direction VD. The second surface is a surface for restraining the deformation in the longitudinal direction HD of the end of the first bend. The third step, while pushing the end portion of the first bend in the first surface, can be carried out by restraining the end portions at the second surface. Thereby, while suppressing that the end of the first bend portion extends in the longitudinal direction HD, it can be deformed the end on the inner side of the vertical direction VD. Incidentally, there may be no distinct boundary between the first and second surfaces. That is, in the manufacturing method of this embodiment, a flange portion bent outward tip of (certain rough flange portion), placed in a recess of the concave mold having a concave portion, the web portion that the tip of the (crude web portion) pressing from the outside in the extending direction.
[0054]
　The second mold may be concave portion is formed. The bottom surface of the recess is that the first surface, the side surface of the recess may be the second surface. For an example of the recess will be described in the first embodiment.
[0055]
　It said at least one specific rough flange portion may include a first and second specific rough flange are aligned in the vertical direction VD. The first mold includes a first inclined surface, the angle formed between the first inclined surface may comprise a 180 ° greater than the second slope. In this case, the second step, the first inclined surface of the first mold press first specific rough flange, and the line by the second inclined surface of the first mold press the second specific crude flange it may be cracking. According to this configuration, simultaneously forming at least two first curved portion. That is, in the manufacturing method of this embodiment, between the two opposing flange portions (specific rough flange portion), by placing the convex mold toward the web portion, the web portion of each distal end thereof flange it may be bent outward in the extending direction. For example convex mold has a protrusion protruding toward the web portion, and two surfaces adjacent to the convex portion, each which faces away from the web portion as the web portion extending outwardly.
[0056]
　Further in this case, the third step may be performed in two second mold disposed in the vertical direction VD so as to sandwich the forging. According to this configuration, simultaneously forming at least two second bending portion.
[0057]
　Hereinafter, the angle formed by the first slope and a second slope, sometimes referred to as "angle P". There is no limitation to the angle P, it may be an angle capable of forming a first bend desired. Angle P, for example, may be in the range of 190 ° ~ 300 ° (range preferably 200 ° ~ 270 °).
[0058]
　The four crude flange portion includes first and second specific rough flange are aligned in the vertical direction VD, it may be made of two normal rough flange not certain rough flange. In this case, the following (1) and / or conditions may be met in (2).
(1) second step in two states usually the crude flange portion is fixed is carried out.
(2) In the third step, the second mold, together with the push the end of the first bend, limits displacement of the normal crude flange portion by pressing the normal crude flange portion.
[0059]
　It said at least one specific rough flange portion may be made from the first and second specific crude flange portion, and the third and fourth particular crude flange are aligned in the vertical direction VD. In this case, all four coarse flanges particular crude flange. In this case, the second step, at the same time the first and second specific crude flange pressed by one of the first slope and the second slope of the first mold, the first to third specific rough flange portion of the other press the first inclined surface of the mold, and may be carried out by pressing by the second inclined surface of the fourth first mold certain crude flange portion of the other. That may push the four specific flange portion so as to sandwich the first die of the two.
[0060]
　The second step may be performed in a state sandwiched by the two third mold forgings from the vertical direction VD. In another aspect, in a state sandwiching the forging at third mold two from a direction perpendicular to the moving direction of the first mold, the second step may be performed. There is no limitation to the third mold, as long as it can fix the forging in the second step.
[0061]
　The third step is a coarse web portion of the forged product may be performed in a state sandwiched by the two fourth die from the front-rear direction HD. In another aspect, in a state sandwiching the forging in the fourth mold two from a direction perpendicular to the moving direction of the second die, the third step may be performed. There is no limitation on the fourth die, as long as it can fix the forging in the third step.
[0062]
　(Front axle beam)
　front axle of the embodiment (front axle beam) can be produced by the production method of this embodiment. Matter manufacturing method described in this embodiment, it is possible to apply to the front axle of the present embodiment, there may be omitted the duplicate description. Also, matters described front axle of this embodiment is applicable to the production method of this embodiment. Incidentally, the front axle of this embodiment may be manufactured by a method other than the manufacturing method of this embodiment.
[0063]
　Front axle of this embodiment includes a web portion, and four flange portions joined to opposite ends of the web portion, the beam portion of the H-shaped cross-section of which comprises a. At least one flange portion of the four flange portions (specific flange portion), in the cross section of the front axle, and a curved portion in which the center line of the thickness of the flange portion is bent in the extending outwardly of the web portion. In the present disclosure, means that simply integrated in the bonding, does not necessarily mean that joining by means of welding or fastening.
[0064]
　Specific flange portion having a curved portion in which the center line of the thickness of the flange portion is bent in the extending outwardly of the web portion may be formed by first and second steps described above. In this case, the first bending portion formed in the second step becomes the bend of the particular flange.
[0065]
　Specific flange portion includes the bent portion (first bent portion). That is, the particular flange portion, in cross-section of the front axle, and a curved portion in which the center line of the thickness of the flange portion is bent in the extending outwardly of the web portion. In this case, the cross section of the front axle, the center of gravity of a particular flange to a position relatively far from the center of gravity of the beam portion is disposed. Therefore, as compared with the flange portion of a conventional front axle extending in a plate shape, it is possible to increase the second moment of the particular flange. As a result, according to the front axle of the present embodiment, it is possible to increase the bending rigidity in the longitudinal direction HD. Further, as compared with conventional flange portion, it is possible to increase the polar second moment of the particular flange. As a result, according to the front axle of the present embodiment, it is possible to increase the torsional rigidity.
[0066]
　The front axle of this embodiment includes a beam portion, and two kingpin mounting portions provided on both ends in the longitudinal direction LD of the beam portion. Beam portion includes a web portion extending in the longitudinal direction LD, and four flange portions projecting forwardly and rearwardly from the respective upper and lower ends of the web portion. At least one of the four flange portions is a specific flange portion including the bend portion. Outer surface of the vertical VD of the front axle beam of the bending portion of the surface is inclined toward the outside of the vertical direction VD after inclined towards the inside of the vertical VD with distance from the web portion.
[0067]
　In one aspect, the bending portion is inclined toward the outside in the vertical direction VD after inclined toward the inside of the vertical direction VD with distance from the web portion.
[0068]
　Bend of a particular flange may be formed by first to third steps described above. In this case, the second bending portion formed in the third step, the bent portion of the particular flange.
[0069]
　Specific flange portion includes the bent portion (second bend). That is, the particular flange portion, in cross-section of the front axle, and a curved portion in which the center line of the thickness of the flange portion is bent in the extending outwardly of the web portion. In this case, the cross section of the front axle, to a limited extent, the center of gravity of a particular flange to a position relatively far from the center of gravity of the beam portion (a position farther than the conventional front axle) is arranged. Therefore, as compared with the flange portion of a conventional front axle extending in a plate shape, it is possible to increase the second moment of the particular flange portion without increasing the cross-sectional size of the front axle. As a result, according to the front axle of the present embodiment, it is possible to increase the rigidity (flexural rigidity in the longitudinal direction HD, and bending rigidity in the vertical direction VD) without increasing the cross-sectional size. Furthermore, in comparison with the conventional flange portion, it is possible to increase the polar second moment of the particular flange portion without increasing the cross-sectional size of the front axle. As a result, according to the front axle of the present embodiment, it is possible to increase the torsional rigidity without increasing the cross-sectional size of the front axle.
[0070]
　In another aspect, the bend portion of one particular flange, when the specific flange portion viewed horizontally from the side which projects, with a portion to be a blind spot on the outer surface in the vertical direction VD. Such bend, since the inverse gradient in the mold forging step, it is difficult to form such a bend only at the die forging process. Therefore, when forming a specific flange by a manufacturing method comprising the die forging step, the above-mentioned bending step (second step or the second and third step) is required. Conversely, the shape of the bent portion can be easily formed by a production method including the above-mentioned die forging step (first step) and bending process (second step or the second and third step). Therefore, the front axle of this embodiment is also advantageous in terms of manufacturing.
[0071]
　As described above, at least one of the four flange portions (one, two, three, or four) is a specific flange portion. In a preferred example, a two or four of the particular flange of the four flange portions. Two specific flange portion may be arranged in the vertical direction VD.
[0072]
　Inner surface of the vertical VD of the front axle of the bend of the surface may be inclined toward the outside of the vertical direction after inclined toward the inside of the vertical with increasing distance from the web portion. Alternatively, the entire inner surface of the vertical VD of the front axle of the surface of the bent portion may be inclined toward the outside of the vertical direction VD.
[0073]
　End of the bent portion may not protrude to the outside of the vertical direction VD than a portion other than the end portion. According to this configuration, rigidity in the compact can be realized with high front axle.
[0074]
　As described above, the bent portion, at least a portion of the region between the two spring mounting seat may be formed in (some or all). For example, bend 50% of the region between the two spring mounting seat (based on the length in the longitudinal direction LD) may be formed above.
[0075]
　(Manufacturing apparatus)
　In another aspect, the present invention relates to first and second apparatus for manufacturing a front axle. First manufacturing device comprises a mold described above to be used in the second step, and a mechanism for moving the mold as described above. The second manufacturing apparatus includes a mold described above used in the third step, and a mechanism for moving the mold as described above. The mechanism for moving the mold can be applied to mechanisms that have been used in such known pressing apparatus.
[0076]
　The following description with reference to the drawings exemplary embodiments of the present invention. The embodiments described below are exemplary, at least a portion of the configuration in the following embodiment, can be replaced with the above-described configuration. In the following description, it may be omitted from redundant explanation are denoted by the same reference numerals to like parts. Moreover, are all figures schematically shown below, may be omitted and unnecessary portions in the description.
[0077]
　(First Embodiment)
　In the first embodiment, an example of a front axle of the present invention. A perspective view of the front axle 100 of the first embodiment, shown in FIG. A front view of the from the front of the front axle 100 viewed horizontally front axle 100, shown in FIG. A top view of the front axle 100 shown in FIG. Furthermore, the cross-sectional view taken along the line IV-IV in FIG. 3, shown in FIG. 4. The drawing described in these figures and the following, the front axle 100 (or forgings 200) may indicate the forward direction FWD, vertical VD, and the front-rear direction HD. Similarly, the figures may indicate a longitudinal direction LD of the beam portion 110 (or coarse beam portion 210).
[0078]
　Referring to FIG. 1, the front axle (front axle beam) 100 includes a beam portion 110, and two kingpin mounting portion 150 provided on both ends in the longitudinal direction LD of the beam portion 110. The kingpin mounting portion 150, through hole kingpin is attached is formed. Normally, the front axle 100 has a generally symmetrical shape about a center in the vehicle width direction, and have a generally arcuate shape as a whole. As shown in FIG. 2, the kingpin mounting portion 150, the tire 1 is connected via a kingpin.
[0079]
　Beam unit 110 includes a web portion 120, and four flange portions 130. Four flanges 130 is projected forward and backward from the respective upper and lower ends of the web portion 120. That is, four one of the flange portion 130 protrudes forwardly from the upper end of the web portion 120, one protrudes rearward from the upper end of the web portion 120, one protrudes forward from the lower end of the web portion 120, 1 One protrudes rearward from the lower end of the web portion 120. In another aspect, the beam portion 110 includes a web portion 120, and four flange portions 130 which are joined to both ends of the web portion 120 has a H-shaped cross section of the. At least one of the four flanges 130 is a specific flange portion 131 including the bending portion 132. In FIGS. 1 to 4, all four flange portions 130 illustrates a case where a specific flange portion 131.
[0080]
　Here, the four specific flange portion 131, and first to fourth specific flange portion 131a-131d. In Figure 4, as an example, the particular flange portion 131 are arranged vertically at the front of the web portion 120, and first and second specific flange portion 131a and 131b. Furthermore, the particular flange portion 131 are arranged vertically at the rear of web portion 120, and the third and fourth particular flange portion 131c and 131d. Note that any particular flange portion or the first to fourth specific flange portion is arbitrary. For example, two specific flange portion that in tandem, or as the first and second specific flange portion.
[0081]
　As shown in FIG. 4, the outer surface 132s in the vertical direction VD of the surface of the curved portion 132, inclined toward the outside in the vertical direction VD after inclined toward the inside of the vertical direction VD with distance from the web portion 120 doing. That is, the surface 132s includes a surface 132sa which is inclined toward the inside, and a surface 132sb which is inclined towards the outside. In another aspect, the surface 132 s, the recess 132c is formed.
[0082]
　In another aspect, the front axle 100 of the present embodiment can be interpreted as follows. Figure 14 shows a cross-section of the beam portion 110 of the front axle 100 of the present embodiment corresponding to FIG. Beam portion 110 has a cross-section of H-type. Beam unit 110 includes a web portion 120, and four flange portions 131a ~ 131d joined to both ends of the web portion 120. Flange 131a ~ 131d is provided with a curved portion in which the center line of the flange portions 131a ~ 131d of the thickness flex outwardly in the extending direction of the web portion 120 (vertical direction VD). One-dot chain line shown in FIG. 14 is the center line of the flange portions 131a ~ 131d of the thickness.
[0083]
　When the bending portion 132 from the front-rear direction HD viewed horizontally, the outer surface 132s of the bend 132, there are parts in a dead angle. As described above, such a bend 132, it is difficult to form only by the die forging process.
[0084]
　Inner surface 132t of the vertical VD of the surface of the bent portion 132 may be inclined toward the outside in the vertical direction VD after inclined toward the inside of the vertical direction VD with distance from the web portion 120. Alternatively, the surface 132t may be inclined toward the outside in the vertical direction VD throughout. The inclination can be increased as the distance from the web portion 120.
[0085]
　In one aspect, the cross-section of two specific flange portion 131 are aligned in the longitudinal direction HD (Fig. 4 of the cross-section) is a W-shape. In another aspect, the particular flange section 131, after inclined inwardly in the vertical direction VD with distance from the web portion 120 is inclined outwardly in the vertical direction VD.
[0086]
　Two flange portions 130 projecting from the upper side of the web portion 120, two spring mounting seat 111 is formed. Two spring mounting seat 111 is disposed on the left and right symmetrical positions at a distance. Spring is arranged in the spring mounting seat 111, a vehicle body (including the engine) is mounted on the spring. In the first embodiment, a description is given of a case where the bending portion 132 is formed between the two spring mounting seat 111, may bend 132 in the other portion is formed.
[0087]
　In the example shown in FIG. 4, two boundary 130a of the flange portion 130 (specific flange portion 131) adjacent in the longitudinal direction, lies on the vertical line Lct. Vertical line Lct, in a cross section perpendicular to the longitudinal direction LD, a vertical line passing through the center of the longitudinal direction HD of the web portion 120 (line parallel to the vertical direction VD). In the example shown in FIG. 4, the boundary between the specific flange 131 and the web portion 120 has a rounded shape (R shape). 4, the boundary between the specific flange 131 and the web 120, the R of the terminating (R it away) shape, specific flange portion 131 side of the two end (first end and the third in the flange portion 131a is a straight line connecting the end) in the flange portion 131c. The same applies to the second flange portion 131b and the fourth flange portion 131d side.
[0088]
　In FIGS. 1 to 4, all four flange portions 130, illustrated one example is a specific flange portion 131 including the bending portion 132. However, at least one flange portion 130 may if it has a bent portion 132. For example, among the four flange portions 130, only two flanges 130 arranged in the vertical direction may be a specific flange portion 131. They to the web portion 120 may protrude forward may protrude backward. Alternatively, among the four flange portions 130, only two flanges 130 arranged in the longitudinal direction may be a specific flange portion 131. They may be disposed at the upper end of the web portion 120 may be disposed at the lower end of the web portion 120.
[0089]
　(Second Embodiment)
　In the second embodiment, an example of producing a front axle 100 shown in FIGS. 1 to 4 will be described with reference to the drawings. This manufacturing method includes a first, second, and third steps described below in this order. The first to third step is a hot processing carried out by heating the processing target.
[0090]
　In the first step (the die forging step) to form a predetermined forging by die forging steel. There is no limitation to the die forging step can be carried out by known die forging process. In the die forging process, usually, burrs are formed on the forging. If burrs are formed on the forging, burrs punching step is performed before the second step. There is no limitation on the burr punching process can be carried out by known burr punching process.
[0091]
　Figure 5A is a perspective view showing a part of a cross-section of the forging 200 after burr punching process is performed. Forgings 200 includes a coarse beam portion 210 as the beam portion 110. Crude beam unit 210 includes a coarse web portion 220 serving as the web portion 120, and a plate-shaped four coarse flange portion 230 from each of the upper and lower ends protruding toward the front and rear of the coarse web portion 220. All four rough flange portion 230, a specific crude flange portion 231 becomes a specific flange portion 131. The forging 200, the portion 211 comprising a spring mounting seat 111 is formed.
[0092]
　Section forgings 200 (cross section perpendicular to the longitudinal direction LD), shown in Figure 5B. The cross-section of Figure 5B is a cross-section of a portion to be the bent portion 132. Four specific crude flange portion 231 is composed of first to fourth specific crude flange 231a-231d to be the first to fourth specific flange portion 131a-131d.
[0093]
　Die forging process, rough flange 230 is performed by moving the mold (forging machine) in the direction (front-rear direction HD (direction orthogonal to the extending direction of the rough web portion 220)) that protrudes. Forging die has a center line of the rough web portion 220 in pairs in the boundary. Therefore, the rough flange portion 230 is provided with a gradient for demolding. FIG 5B, showing the angles Q, Q 'of the draft for stamping direction (front-rear direction HD). For this slope, rough flange portion 230 is thinner closer to its end. Boundary portions 230a of the two coarse flange portion 230 adjacent to the front-rear direction HD becomes the upper and lower ends of the forging 200.
[0094]
　Steel as a material for the die forging process typically has a shape suitable for die forging. Such steel can be formed by preforming a billet which is a starting material in the preforming step. That is, the steel material may be a preform. There is no limitation to the preforming step, it may be applied known preforming process. For example, pre-molding step, and the step of squeezing the billet may include bending beating process. Preforming step is usually hot working.
[0095]
　An example of the second step shown in the sectional view of FIG. 6A and 6B. In the second step, the bent towards the outside of the particular by pressing in at least one of the first mold 310 and the crude flange portion 231, (the extending direction of the rough web portion) vertically VD forging 200 1 forming a bend 232a of the particular crude flange portion 231. At least one of the first mold 310 is moved back and forth direction HD (direction orthogonal to the extending direction of the rough web portion).
[0096]
　In the second step First, as shown in FIG. 6A, placing the forging 200 between the first mold 310 and the first mold 310 of the upper downward. The first mold 310 includes a first inclined surface 310a, the angle P formed between the first inclined surface 310a is a 180 ° greater than the second slope 310b. Angle P is in the range described above. The first inclined surface 310a and the second inclined surface 310b, respectively, may be a curved surface. In another aspect, the first mold 310 is convex mold, a convex portion projecting toward the rough web portion, and two surfaces adjacent to the convex portion (first inclined surface 310a and the second inclined surface 310b) equipped with a. Each their faces, spaced from the outer higher roughness web portion in the extending direction of the rough web portion.
[0097]
　In the example shown in FIG. 6A, the particular crude flange portion 231 extends direction (front-rear direction HD) and angle between the first inclined surface 310a (or the second inclined surface 310b) is is half the angle P. Note that the angle between the direction specified roughness flange portion 231 extending a first inclined surface 310a, and the angle between the direction specified roughness flange portion 231 extends and a second inclined surface 310b, may be different.
[0098]
　The second step, as shown in FIG. 6A, may be performed in a state sandwiched by forging 200 in the vertical direction VD third mold 330 from the two (coarse web portion extending direction of). By fixing across the forging 200 in the third mold 330, it can perform the second step accurately. Furthermore, by fixing across the forging 200 in the third mold 330, it is possible to reduce the possibility that buckling occurs at the boundary portion of the crude flange portion 230 adjacent to the longitudinal direction (or a particular rough flange portion 231).
[0099]
　Next, as shown in FIG. 6B, reduction forgings 200 lowers the first mold 310 of the upper. More specifically, the one first inclined surface 310a of the first die 310 pushes the first specific crude flange portion 231a, and pushes the second specific crude flange portion 231b by the second inclined surface 310b. In this case, press the third specific crude flange portion 231c by the other of the first inclined surface 310a of the first die 310, and presses the fourth particular crude flange portion 231d by the second inclined surface 310b. In another aspect, during two particular crude flange portion opposite (first and second specific crude flange portion 231a and 231b, the third and fourth particular crude flange portion 231c and 231d), the crude web portion toward putting convex mold (first mold 310 of the upper and lower) with. Thus, bending the respective tips of their particular crude flange portion on the outer side of the extending direction of the rough web portion (vertical direction VD). The second step, the first bending portion 232a is formed to a specific flange portion 231a ~ 231d.
[0100]
　An example of a next third step shown in the sectional view of FIG. 7A and 7B. In the next third step, deforming the end portion 232ae toward the inside of at least one second mold 320 by a first curved portion 232a of the end portion by pressing the 232ae vertical direction VD (the extending direction of the rough web portion) by the second bending portion 232b is formed to a specific crude flange 231a ~ 231d. At least one of the second mold 320 is moved in the vertical direction VD.
[0101]
　In the third step First, as shown in FIG. 7A, placing the forging 200 between the second mold 320 and second mold 320 in the upper downward. The second mold 320, the concave portion 320g is formed. Recess 320g includes a first surface (bottom surface) 320a, a second surface (side surface) 320b. The first surface 320a is the end 232Ae, a surface pressed toward the inside of the vertical direction VD forging 200. Second surface 320b is a surface for restraining the deformation in the longitudinal direction HD forging 200 of the end portion 232Ae. In another aspect, the second die 320 is a concave mold having a recess 320 g.
[0102]
　The third step is, as shown in FIG. 7A, a state sandwiched by the fourth die 340 from two crude web portion 220 (the direction orthogonal to the extending direction of the rough web portion 220) the longitudinal direction HD forging 200 it may be carried out in. By fixing across the forging 200 in the fourth mold 340, it can be performed a third step accurately. Furthermore, by fixing across the forging 200 in the fourth mold 340, crude web portion 220 can be prevented from being deformed.
[0103]
　Next, as shown in FIG. 7B, reduction forgings 200 lowers the second mold 320 of the upper. Specifically, pushing the first specific end 232ae of crude flange portion 231a by the first surface 320a of the upper second mold 320, and the second surface 320b end of the second specific crude flange portion 231b pressing the part 232ae. In this case, press the end 232Ae of a third particular crude flange portion 231c by the other of the first surface 320a of the second die 320, and the end portion of the fourth particular crude flange portion 231d by the second surface 320b 232Ae push. In another aspect, while the distal end of a particular crude flange 231a ~ 231d which are bent outward, and restrained from the outside in the direction orthogonal to the extending direction of the rough web portion 220 (front-rear direction HD), the tip crude web pressing from the outside in the extending direction of the part 220 (vertical direction VD). In yet another aspect, a distal end of a particular crude flange 231a ~ 231d which are bent outward, concave mold (second mold 320) placed in the recess 320g of the extending direction of the distal crude web portion 220 ( up-and-down direction VD) to push from the outside. The third step, a second bend 232b is formed to a specific flange portion 231a ~ 231d.
[0104]
　In this manner, forging 201 having a second bending portion 232b is obtained. The second bend 232b typically have the same shape as the bent portion 132. That is, normally, the second bending portion 232b is the bend 132 as it is.
[0105]
　7A and 7B, the first surface 320a is shown a second mold 320 is flat. In the second mold 320, the position of the boundary portion 130a in the vertical direction VD (see FIG. 4), and the position of the end portion 232ae in the vertical direction VD is the same. On the other hand, the position of the first surface 320a pushing the end 232Ae, by shallower than other locations on the bottom surface, it is possible to deform the end 232Ae inside the boundary 130a. In this case, the maximum width in the extending direction of the web portion 220 (vertical direction VD) is the width of a portion of the web portion 220.
[0106]
　The first to third steps described above, forgings 201 having substantially the same outer front axle 100 is obtained. The resulting forged product 201 may be subjected to various processes as needed. Examples of these processes, the shaping process, drilling process, the heat treatment step, bend-up step, surface treatment step, and the like coating process. These steps can be carried out by known methods. In this way, the front axle 100 is manufactured.
[0107]
　Above in the manufacturing method, the contour of each cross section of the second step prior to forging 200 and a third after the step forging 201, shown superimposed in Figure 8. Further, in FIG. 8 shows a rectangle that encloses the contour of the forged product 200 by a one-dot chain line.
[0108]
　One way to improve the rigidity, it is conceivable to lengthen the flange portion in the front-rear direction HD. However, just when longer flange portion in the longitudinal direction HD, the size in the longitudinal direction HD of the front axle is increased. On the other hand, according to the manufacturing method of this embodiment includes first to third step, as shown in FIG. 8, it is bent flange portion extending in the longitudinal direction HD. That is, the flange portion is provided with a second bend. Therefore, it is possible to reduce the size of the front-rear direction HD. That is, according to the manufacturing method of this embodiment, it is possible to suppress an increase in size improves the rigidity.
[0109]
　Further, according to the manufacturing method of this embodiment includes first and second step, as shown in FIG. 6B, and bend the leading end portion of the flange portion on the outer side of the extending direction of the web portion (vertical direction VD) . That is, the flange portion comprises a first curved portion. Therefore, according to the manufacturing method of this embodiment, it is possible to improve the rigidity.
[0110]
　(Other examples)
　In the above example, has been described a case where all four flange portions 130 to produce a front axle 100 is a specific flange portion 131. However, of the four flange portions 130, even if only the vertical direction VD 2 one flange portion 130 that are arranged in is the specific flange portion 131 can be similarly prepared.
[0111]
　Hereinafter, there are cases where a normal crude flange portion 230 is not a particular rough flange portion 231, commonly referred to as crude flange 230n. Particular when the rough flange portion 231 and the normal rough flange 230n are arranged in the longitudinal direction HD, bending process (second and third steps) in particular crude flange portion 231 only to the bend 232 of them forming It is. In that case, a force is applied only to certain rough flange portion 231, a boundary portion between the rough web portion 220 with a particular crude flange portion 231 as a fulcrum, there is a possibility that normal rough flange 230n is displaced. In order to suppress such displacement, it is preferable to perform the bending process while suppressing the displacement of the normal crude flange 230n. An example of the second step of inhibiting the displacement of the normal crude flange 230n, shown in the sectional view of FIG. 9A and 9B.
[0112]
　Sectional view of Figure 9A shows the state before the start of the deformation in the second step, the cross-sectional view of FIG. 9B shows a state when deformed completed in the second step. Forging 200 illustrated includes a first and second specific crude flange portion 231a and 231b that are aligned in the vertical direction VD, the two that are aligned in the vertical direction and a normal rough flange 230n. Two normal rough flange 230n is arranged to fit into the recess of the fixed mold 350. In other words, the fixed die 350, a recess is usually rough flange 230n fitted is formed. By using a fixed 350 can perform the second step in two states usually fixed crude flange 230n. Above the two specific crude flange portion 231, first mold 310 is disposed.
[0113]
　In the second step, in the normal coarse flange portion 230n, a force to deform inward in the vertical direction VD acts. Therefore, rather than the fixed 350 shown in FIG. 9A, it may be used a mold for fixing only the inner part of the normal crude flange 230n.
[0114]
　Next, as shown in FIG. 9B, lowers the first mold 310, pressing the specific crude flange portion 231a at the first slope 310a, and presses a particular crude flange portion 231b in the second inclined surface 310b, a first bend to form a part 232a. The second step in this manner is carried out.
[0115]
　An example of a next third step shown in the sectional view of FIG. 10A and 10B, showing another example of a third step in cross-section in FIG. 11A and FIG. 11B. Steps shown in FIGS. 10A and 10B is the same as the process described in FIGS. 7A and 7B, without redundant description. In the third step, the second die 320, to form a second curved portion 232b press the end 232ae of the first bending portion 232a. In this way, the third step is performed.
[0116]
　In the third step shown in FIGS. 11A and 11B, using the second mold 320 having a surface 320c to press the normal crude flange 230n. The second mold 320 shown in FIG. 11A has a recess 320 g. Recess 320g includes a first surface 320a, a second surface 320b, and a surface 320c to press the normal crude flange 230n.
[0117]
　In the third step shown in FIGS. 11A and 11B, it is possible to use a fixed 340. In this example, a fixed type 340, is used as the fixed mold 340a and the fixed mold 340b. Fixed 340a abuts the rough web portion 220. Fixed 340b has a shape in contact with the inner surface and coarse web portion 220 of the normal crude flange 230n. By using the fixed mold and 340b and the second mold 320 having a third surface 320c, it can accurately position the normal crude flange 230n.
[0118]
　In the third step, first, as shown in FIG. 11A, the forging 200 is disposed between the second die 320 and second die 320 above the lower, the fixed die 340a and the stationary die 340b forgings 200 to fix.
[0119]
　Next, as shown in FIG. 11B, lowers the second mold 320 of the upper, the first surface 320a and second surface 320b pushes the first bend portion 232a to form a second bend 232b. In this case, press the normal crude flange portion 230n by the third surface 320c. This allows suppressing the displacement of the normal crude flange 230n.
[0120]
　As described above, forgings 201 having a second curved portion 232b is formed. Since the above-described processes for after the third step will be omitted.
[0121]
　Note that when only one of the four flange portions 130 is a specific flange portion 131 may be Magere the particular flange section 131 only in the second and third steps. In this case, as described above, while suppressing the displacement of the normal crude flange 230n adjacent to the front-rear direction with a specific roughness flange portion 231, it is preferable to carry out the second and third steps.
Example
[0122]
　Hereinafter, more detailed description of the examples the invention.
[0123]
　In this Example it was evaluated by simulation and rigidity of the beam portion of the present embodiment having the bent portion, and a rigidity of the beam portion of the comparative example having no bent portion. In the simulation, as a model of the beam portion, the cross-sectional shape perpendicular to the longitudinal direction length constant is assumed to 100mm model. The physical properties of samples 1 and 2, assuming a Young's modulus and 210 GPa, and Poisson's ratio was assumed to 0.293. The simulation was carried out by the finite element method. Mass samples 1 and 2 were the same. That is, the vertical cross-sectional area in the longitudinal direction was the same in samples 1 and 2.
[0124]
　Sample 1 of the cross-sectional shape of the present embodiment, and FIG. 12 shows a sample 2 of the cross-sectional shape of comparative example. In cross-section (longitudinal direction LD in the cross section perpendicular) shown in FIG. 12, the cross section of Sample 1 and Sample 2 are and vertically symmetrical symmetrical. The flange portion of the sample 2, it was assumed that the projecting horizontally in the longitudinal direction HD from the upper and lower ends of the web portion. Incidentally, (see FIG. 5B) angle Q, Q 'of the draft of the sample 2 was assumed to 5 °.
[0125]
　As shown in FIG. 12, suppose the X and Y coordinates as the origin centroid CT of each sample in the cross section of FIG. 12. X coordinate is parallel to the longitudinal direction HD of the beam portion, Y coordinate is parallel to the vertical direction VD of the beam portion. A region X and Y coordinates are both positive, namely one quarter of the cross section was determined centroid. Position of the center of gravity CG1 of samples 1, and shows the position of the center of gravity CG2 of the sample 2 in Figure 12. These coordinates (unit: mm) are shown below.
The center of gravity of the sample 1 CG1: (X, Y) = (22.111,23.318)
Sample 2 of the center of gravity CG2: (X, Y) = (21.982,21.135)
[0126]
　As mentioned above, X and Y coordinates of the center of gravity CG1 of the sample 1 of this embodiment was greater than those of the center of gravity CG2 of sample 2 of Comparative Example. By this X-coordinate and Y-coordinate is large, an effect that allows an increase in the polar second moment against torsion and second moment, also the increase of the moment of inertia with respect to bending deformation by the vertical load is light weight relative to bending deformation by longitudinal load It is obtained.
[0127]
　For Samples 1 and 2, the rigidity when a load is applied as shown in FIG. 13 was obtained by simulation. Specifically, the one end face of one of the two end faces restrained, the load is applied in a direction indicated by an arrow shown in FIG. 13 the other end face. The load of the bending back and forth shown in FIG. 13, to determine the stiffness in the longitudinal direction. The upper and lower bending load of 13 to determine the vertical rigidity. The load of the rotation torque shown in FIG. 13, to determine the torsional rigidity. The evaluation results are shown in Table 1.
[0128]
[Table 1]

[0129]
　As shown in Table 1, longitudinal rigidity and torsional rigidity of the sample 1 of the present embodiment was higher than those of sample 2 of Comparative Example 2. Further, the vertical stiffness of the sample 1 was significantly higher than that of sample 2.
[0130]
　As is apparent from the above results, by using a beam portion having a bent portion of the present embodiment, the mass is the same rigidity higher front axle is obtained. This indicates that you can weight the front axle without reducing a predetermined rigidity. This further shows that there is a possibility of realizing a conventional equal or rigid conventional products equal to or less than the cross-sectional size.
Industrial Applicability
[0131]
　The present invention can be used in the front axle beam.
DESCRIPTION OF SYMBOLS
[0132]
　100: front axle (front axle
　beam) 110: beam portion
　111: spring mounting seat
　120: web portion
　130: flange portion
　131: a specific flange portion
　132: curved portion
　150: kingpin mounting portion
　200, 201: forging
　210: crude beam part
　220: crude web portion
　230: crude flange
　230n: normal crude flange
　231: specific crude flange
　232a: first bend
　232b: second bend
　310: first mold
　310a: first slope
　310b: the second inclined surface
　320: second mold
　320a: first surface
　320b: second surface
　330: third mold
　340: fourth dies
　LD: longitudinal
　HD: longitudinal direction
　VD: vertical direction

WE CLAIM

And the web portion, the method of manufacturing a front axle beam with a beam portion of the H-shaped cross-section of which comprises a flange portion which is joined to the opposite ends of the web portion, and
　in said transverse plane, gold said flange portion housed in a mold, forging sandwich in the mold in the extending direction of the flange portion,
　in the transverse section, the said tip by pressing the tip of the flange portion in the direction perpendicular to the extending direction of the web portion web bend outwardly extending direction of the parts, the manufacturing method of the front axle beam.
[Requested item 2]
　Opposed putting a convex mold toward said web portion between said flange portion, bending the tip outwardly extending direction of the web portion, the front axle beam method according to claim 1.
[Requested item 3]
　In the cross section, the tip bent, while constrained from the outside in a direction perpendicular to the extending direction of the web portion, pushing from the outside in the extending direction of the web portion, according to claim 1 or claim 2 method of manufacturing the front axle beam.
[Requested item 4]
　In the cross section, the maximum width in the extending direction of the web portion of the front axle beam is the width of a portion of the web portion, the manufacturing method of the front axle beam according to claim 3.
[Requested item 5]
　The convex mold has a protrusion protruding toward the web portion, and a surface adjacent to said convex portion,
　spaced in the transverse plane, the plane from the web portion as the web portion extending outwardly to the front axle beam method according to any one of claims 2-4.
[Requested item 6]
　The bent the tip, placed in the recess of the concave mold having a recess, pressing from the outside in the extending direction of the web portion, the manufacturing method of the front axle beam according to any one of claims 3-5 .
[Requested item 7]
　And the web portion, said a front axle beam comprising a flange portion, a beam portion of the H-shaped cross-section of which comprises a joined to both ends of the web portion,
　the flange portion, in the cross section, the flange portion the center line of the thickness comprises a curved portion bent in the extending direction outer side of the web portion, the front axle beam.