Technical field
[0001]
The present disclosure relates to a manufacturing method and automotive parts for automotive parts.
BACKGROUND
[0002]
And pressing the crushed hollow tube (mother tube) and a pipe outer side into the tube side, the plastic workpiece obtained by press working are widely used as automobile parts. Hereinafter will be explained with reference to an example torsion beam as a representative example of automotive parts.
[0003]
　Torsion beam suspension apparatus is constituted by a torsion beam and the trailing arm. This torsion beam there is a plate torsion beam and pipe torsion beam. At the end of the axial direction of the pipe torsion beam, pipe end joint portion joined to the trailing arm is provided. Further, in the vicinity of the center of the axial direction of the pipe torsion beam, the torsion portion is provided with a cross-sectional shape in order to ensure the roll stiffness of the vehicle body and molded in a V-or U-shaped. To obtain a cross-sectional shape of the torsion portion, in the manufacturing method of the pipe torsion beam, it is crushed to the tube side from the outer tube side along the base pipe by pressing in the axial direction (e.g., JP-A-2011-635 ).
[0004]
　The torsion beam is to fatigue deformed by external force received from the road surface during use, it is necessary to consider the material, shape, step without fatigue failure. Also has been required weight from the viewpoint of the torsion beam of fuel efficiency, it is important to achieve both fatigue properties improvement and weight reduction. These solutions techniques have been proposed, can be aggregated into a 4-point follows roughly.
[0005]
(1) stress concentration and technologies related to the shape of the torsion beam to improve fatigue characteristics by avoiding local deformation (e.g., JP-2007-76410, JP-JP 2013-52740).
(2) raising the hardenability to material strength after molding, techniques for improving the fatigue properties without removing the residual stress (e.g., JP 2001-321846).
(3) the residual stress during molding is removed by annealing (to use a material that does not face softened during annealing. For example, JP-A-2009-155730) a technique for improving fatigue properties
(4) that can reduce the residual stress technology relating molding method (e.g., JP 2013-91433).
Summary of the Invention
Problems that the Invention is to Solve
[0006]
　Among the above (1) technology shape capable both parts rigidity and weight reduction is a limited application range is narrow. (2), (3) the technique requires heat treatment, there is a problem in the quality control and production cost. Therefore, from the viewpoint of cost reduction and global procurement of torsion beam, a technique for improving fatigue properties without heat treatment is required. Further, if the compressive residual stress not only reduces the tensile residual stress in the tube surface, thereby improving the fatigue properties because of the effect of closing the fatigue crack occurring in the tube surface. Therefore to generate a compressive residual stress to improve fatigue characteristics by techniques it has also required. Therefore, the present inventors have aimed at the development of new technology in terms of (4).
[0007]
　The present inventors have found that in JP 2013-91433, has developed a method of reducing the residual tensile stress by tube expansion of the high residual stress sites after molding the torsion beam first. However, this method, there is a possibility that it is impossible to sufficiently improve the fatigue properties of the torsion beam.
[0008]
　The present disclosure in view of the aforementioned, even without quenching or annealing after molding, to obtain a luminal surface tension automotive parts residual stress to reduce to improve the fatigue characteristics of the deformable section at the deformable portion providing a component manufacturing method and automobile parts for automobiles that can be an object.
Means for Solving the Problems
[0009]
　Manufacturing method of one embodiment automobile parts of the present disclosure is a hollow tube formed by a composite material comprising a metal material or a metal and a resin, extravascular direction by pressing a portion of said hollow tube after deforming beyond the axis of the hollow tube into the tube side, a forming step in which a portion of the hollow tube forming the deformable portion which is deformed into a concave shape, of the closed cross section the deformable portion is configured, the high residual stress sites to out-of-plane deformation, comprising a deformation step.
[0010]
　Automobile parts other aspects of the present disclosure includes a cylindrical portion formed by a composite material comprising a metal material or a metal and a resin, is provided axially outwardly of the tubular portion, with respect to the tubular portion part of the peripheral wall Te is connecting a first deformation portion which is deformed in a concave shape across the axis of the tubular portion from the pipe outer side into the tube side, and the cylindrical portion and the first deformation portion, the tubular portion in closed section perpendicular to the modification portion having a second deformation portion which the deformation is gradually changed toward the first deforming portion, and the axial direction of the tubular portion of the second deformation portion from opposed It includes a convex or concave plane deformation portion formed respectively in a portion, a.
Effect of the invention
[0011]
　According to the manufacturing method and parts for automotive automobile parts of the present disclosure, without quenching or annealing after molding and to reduce the tensile residual stress of the inner surface to improve the fatigue characteristics of the deformable section at the deformable portion it is possible to provide a manufacturing method and automobile parts automotive parts can be obtained automotive parts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012]
[1] Figure 1 is a perspective view of the automotive part, a torsion beam of the first embodiment.
FIG. 2 is a bottom view of the torsion beam shown in FIG. 1 from below.
FIG. 3 is a sectional view taken along the line 3-3 in FIG.
[4] FIG. 4 is a sectional view taken along line 4-4 of FIG.
FIG. 5 is a perspective view of a section of the torsion beam as viewed upside down as shown in FIG.
[Figure 6A] Figure 6A is a cross-sectional view of a mold for pressing a hollow tube.
[Figure 6B] Figure 6B is a side sectional view of a mold showing a state of compressing the intermediate product in the axial direction.
[7] FIG. 7 is a cross-sectional view of a mold showing a state in which the hollow tube by press working shown in FIG. 6A.
[8] FIG. 8 is an enlarged view of a portion indicated by an arrow 8X in FIG.
[9] FIG. 9 is a cross-sectional view of a mold showing a state in which mold opening of the mold shown in Figure 7.
[10] FIG. 10 is an enlarged view of a portion indicated by arrow 10X in Fig.
[11] FIG 11 is a cross-sectional view of a mold for hydroforming the intermediate molded article.
[12] FIG 12 is a cross-sectional view of a mold showing a state in which mold closing the mold shown in Figure 11.
[13] FIG 13 is an enlarged view of a portion indicated by arrow 13X in Fig. 12.
[14] Figure 14 while the action of fluid pressure in the interior of the intermediate molded article shown in FIG. 12 is a cross-sectional view of a mold showing a state of compressing the intermediate product in the axial direction.
[15] FIG 15 is an enlarged view of a portion indicated by arrow 15X in Fig. 14.
[16] FIG 16 is a cross-sectional view of a mold showing a mold opening state of the mold shown in Figure 15.
[17] FIG 17 is an enlarged view of a portion indicated by arrow 17X in Fig. 16.
[18] FIG 18 is a cross-sectional view of a mold of the second embodiment for hydroforming the intermediate molded article.
[19] FIG. 19, while closing the mold the mold shown in FIG. 18 is a cross-sectional view of a mold showing a state in which the intermediate molded article and pressing.
FIG. 20 is an enlarged view of a portion indicated by arrow 20X in Fig. 19.
FIG. 21, while by the action of fluid pressure in the interior of the intermediate molded article shown in FIG. 20 is a cross-sectional view of a mold showing a state of compressing the intermediate product in the axial direction.
[22] FIG. 22 is an enlarged view of a portion indicated by arrow 22X in Fig. 21.
[23] FIG 23 is a cross-sectional view of a mold showing a state in which mold opening of the mold shown in Figure 22.
FIG. 24 is an enlarged view of a portion indicated by arrow 24X in Fig. 23.
[FIG. 25A] FIG 25A is a stress distribution diagram showing a stress state at the site where the residual stress is increased at the time of pressing a hollow tube with a manufacturing method of the present disclosure.
[FIG. 25B] FIG. 25B, at the site shown in Figure 25A, is a stress distribution diagram showing a release stress at the time of releasing the pressed stress of the hollow tube.
[FIG. 25C] FIG. 25C, at the site shown in Figure 25A, is a stress distribution diagram showing a stress state of the intermediate molded article (stamped hollow tube) after spring back.
[Figure 26A] Figure 26A is a stress distribution diagram showing a stress state at the site where the residual stress at the time of molding the intermediate molded article by the action of fluid pressure in the interior of the intermediate molded article using the manufacturing method of the comparative example is higher it is.
FIG 26B] FIG 26B is at the site shown in Figure 26A, is a stress distribution diagram showing a release stress at the time of releasing the intermediate molded article which hydraulic pressure is applied.
FIG 26C] FIG 26C is at the site shown in Figure 26A, is a stress distribution diagram showing a stress state of the finished product (torsion beam) after spring back.
FIG 27A] FIG 27A is a stress distribution diagram showing a stress state at the site where the residual stress at the time of the production method of the present disclosure by applying a fluid pressure to the interior of the intermediate product used in the molding of the intermediate molded article becomes high it is.
[FIG. 27B] Figure 27B at the site shown in Figure 27A, is a stress distribution diagram showing a release stress at the time of releasing the intermediate molded article which hydraulic pressure is applied.
[FIG. 27C] FIG. 27C, at the site shown in Figure 27A, is a stress distribution diagram showing a stress state of the finished product (torsion beam) after spring back.
[FIG. 28] is an explanatory view of an analysis model in the second modified portion of the first embodiment of the present disclosure.
FIG. 29 is an explanatory view of an analysis model in the second modified portion of the embodiment 11 of the present disclosure.
DESCRIPTION OF THE INVENTION
[0013]
[First Embodiment]
　Hereinafter, a method of manufacturing automotive component according to the first embodiment (hereinafter abbreviated to as "manufacturing method".) Will be described.
　First, describes automobile part produced by the production method of this embodiment, it will be described the manufacturing apparatus used in the method of the present embodiment. Then, a method for manufacturing the present embodiment.
[0014]
　Automobile parts produced by the production method of this embodiment, the hollow tube made of a composite material made of a metal material or a metal and a resin (base tube) 20 pressing and hydroforming the (hydroforming) a torsion beam 22 formed. The torsion beam 22 is used in an automobile suspension system (not shown), a component for connecting the left and right trailing arms 23. Incidentally, automobile parts produced by the production method of this embodiment is not limited to the torsion beam.
[0015]

　torsion beam 22 as shown in FIGS. 1 and 2, a cylindrical portion 24 formed by a composite material comprising a metal material or a metal and resin, one axial direction of the cylindrical portion 24 a torsion portion 26 provided on a side (an example of the deformed portion), and a second deformation portion plane deformation portion 28 provided in the 34 to be described later of the torsion portion 26, a.
[0016]
(Tubular portion 24)
　as shown in Figures 2 and 5, the tubular portion 24 are respectively provided on both sides in the axial direction of the torsion beam 22. In other words, the torsion portion 26 is provided in the axial direction of the intermediate portion of the cylindrical portion 24. The tubular portion 24 has a substantially rectangular tubular. Further, the cylindrical portion 24, left and right trailing arms 23 there is a tube end joint portion joined.
[0017]
(Torsion portion 26)
　as shown in FIG. 2, the torsion portion 26 is a portion for securing the roll stiffness of the vehicle body of the torsion beam 22. The torsion portion 26, by deforming beyond the axis CL of the cylindrical portion 24 from the pipe outer side into the tube side by pressing, which will be described later part of the hollow tube 20, is formed in the cylindrical portion 24 it is a part that was deformed toward the pipe outer side into the tube side.
[0018]
　Further, the torsion portion 26 includes a first deformation portion 32 (see FIG. 3), connecting the first deformable portion 32 and the cylindrical portion 24, the second deformation portion 34 (refer to FIG. 4). First deformation portion 32 is a portion where part of the peripheral wall 25 relative to the tubular portion 24 is deformed in a concave shape across the axis CL from the pipe outer side to the tube side. The first deformable portion 32 taken along the axial direction is constant. On the other hand, the second deformation portion 34 is a portion partially having increased gradually deformation amount from the pipe outer side into the tube side of the peripheral wall 25 toward the cylindrical portion 24 to the first deformation portion 32.
[0019]
　Further, in the present embodiment, as shown in FIG. 3, it closed cross section which constitutes the first deformation portion 32 is a V-shape. Incidentally, closed cross-section which constitutes the first deformation portion 32 may be a U-shaped or C-shaped. The cross-sectional shape of the torsion portion 26 is formed by press working to be described later.
[0020]
(Out-of-plane deformation portion 28)
　as shown in FIGS. 4 and 5, out-of-plane deformation portion 28, in the closed cross section perpendicular to the axial direction of the cylindrical portion 24 of the second deformation portion 34, to each other and deformed into a concave shape They are respectively formed in the opposing portions. Specifically, out-of-plane deformation portion 28 are respectively formed in a portion opposed to each other in the vicinity of the opening end of the V-shape. Also, out-of-plane deformation portion 28 of the present embodiment is a out-of-plane deformation is convex portion was such that the convex peripheral wall 25 from the tube side to the pipe outside direction.
[0021]

　Next, a description will be given of a manufacturing apparatus for an automobile parts of the present embodiment.
　As shown in FIGS. 6A and 11, the manufacturing apparatus 40, after forming the intermediate product a hollow tube 20 by pressing a device for forming the torsion beam 22 by hydroforming. Manufacturing apparatus 40, and an upper mold 44 and lower mold 46 for molding the intermediate molded article 21 a portion of the hollow tube 20 by pressing.
[0022]
　Upper mold 44, a portion of the hollow tube 20 and the press portion 44A to deform by pressed towards the (upper portion in FIG. 6A and FIG. 7) from the pipe outer side into the tube side, V-shaped torsion section 26 recess 44B for forming the opening end portion and a molding portion 44C formed of. The manufacturing apparatus 40 of the present embodiment, the upper mold 44 descends (in the present embodiment the pressing direction (arrow P direction)) is configured to respect the lower die 46, the present disclosure is the configuration need not be limited to. For example, it may be configured to lower die 46 is raised relative to the upper die 44. Further, the upper mold 44, the press portion 44A is relatively movable in the pressing direction relative to the molding portion 44C.
[0023]
　The lower die 46, the recess 46A for forming the top portion 26A of the torsion portion 26 (lower portion in FIG. 6A and FIG. 7) is formed.
[0024]
　The manufacturing apparatus 40 includes a moving device 48 for relatively moving the upper mold 44 and the lower mold 46, and a pressure device 50 for moving the press section 44A in the pressing direction.
[0025]
　In the present embodiment, the mobile device 48 is configured to being connected to the upper mold 44, it moves the upper mold 44 relative to the lower die 46 (moved downward in FIG. 6A). The mobile device 48 is configured, for example, such as a hydraulic cylinder.
[0026]
　Pressure device 50 is connected to the press portion 44A of the upper die 44, the move in the pressing direction of the press section 44A to the rest of the upper die 44 (FIGS. 4 and 5, downward and it is configured to move) Te. The pressure device 50 is, for example, a hydraulic device, and the like electric drive apparatus or the like.
[0027]
　The manufacturing apparatus 40 includes an upper mold 45 for molding the plane deformation portion 28 bent back part of the intermediate product (see FIG. 11) by hydroforming.
[0028]
　The upper die 45 includes, as shown in FIG. 11, the press portion 44A of the upper die 44, the recess 44B and the molding portion 44C and the respective same shape of the press portion 45A, a recess 45B and the forming unit 45C . This recess 45B, recess 45D in a position corresponding to the out-of-plane deformation portion 28 of the torsion portion 26 is formed. Gap between the More specifically, in a state of pressing the intermediate product 21 in the upper die 45 and the lower mold 46 by the recessed portion 45D, the recess 45B and the open end of the U-shaped second deforming portion 34 (see FIG. 13) can be.
[0029]
　The manufacturing apparatus 40 includes a moving device 49 for relatively moving the upper die 45 and lower die 46, and a pressure device 51 for moving the press section 45A in the pressing direction.
[0030]
　The configuration of the mobile device 49 and the pressure device 51 are each moving device 48 and the pressure device 50 similar configuration. The mobile device 48, 49, pressure device 50 and 51 is controlled by a control device 47.
[0031]
　The manufacturing apparatus 40, in a state suppressing the tubular portion 24 between the upper die 45 and the lower mold 46, the liquid injection apparatus 52 for injecting a liquid into the hollow portion of the cylindrical portion 24, the cylindrical portion 24 the compression in the axial direction (so-called pressing axis) includes a compressor 54 (see FIG. 6B), the a.
[0032]
　Liquid injection device 52 is a device for injecting a liquid through a pair of closed mold 53 for closing both end portions in the axial direction of the intermediate molded article 21, respectively (see FIG. 6B) in the hollow portion of the cylindrical portion 24. The fluid pressure of the liquid by the liquid injection apparatus 52 is a second deformation portion 34 is set to a size that is allowed to out-of-plane deformation. That is, in a state in which pressing the tubular portion 24 between the upper die 45 and lower die 46, to inject fluid into the hollow portion of the cylindrical portion 24 by the liquid injection apparatus 52, one second deformation portion 34 parts are plane deformation portion 28 and plane deformed toward the recess 45D of the upper mold 44 is formed.
[0033]
　Compressor 54, as shown in FIG 6B, the compression one closure type (movable die) 53A and the other closed type (fixed type) 53B is an approach movement in the axial direction of the intermediate molded article 21 intermediate molded article it is a device that.
[0034]

　Next, a method for manufacturing the automobile parts of the present embodiment.
[0035]
　(First setting step)
　First, as shown in FIG. 6A, sets the hollow tube 20 formed by the composite material in the recess 46A of the lower die 46 of the manufacturing apparatus 40 comprising a metal material or a metal and resin .
[0036]
　(Molding step)
　Next, as shown in FIG. 7, to operate the mobile device 48 lowers the upper die 44. Then, by closing the mold the upper mold 44 and the lower mold 46, the torsion portion 26 which is deformed in a concave shape to the hollow tube 20 toward the tube outer side into the tube side (first deformation portion 32 and the second deforming portion 34 included) is molded.
[0037]
　Here, the inner surface I of the second deformation portion 34 of the circle surrounded by parts of FIGS. 7 and 8 (partial residual stress is high), compressive stress C in the circumferential direction is generated.
[0038]
　After pressing, as shown in FIG. 9, to raise the upper die 44. At this time, stamped hollow tube 20 (intermediate molded article) results in springback, stress state of the residual stress is high portion changes as shown in FIG. 10. That is, the inner surface I of the second deformation portion 34, circumferential tensile stress T remains.
[0039]
　(Second setting step)
　Next, as shown in FIG. 11, while leaving the intermediate product in the recess 46A of the lower die 46, replacing the upper die 44 and upper die 45. Thereafter, by operating the moving device 49 lowers the upper die 45. Thus, the intermediate molded article 21 is set in a cavity formed between the upper mold 45 and the lower mold 46 (see FIG. 12).
[0040]
(Deformation step)
　Next, as shown in FIGS. 14 and 15, of the closed cross section second deforming portion 34 of the intermediate molded article 21 is configured, to out-of-plane deformation of the high residual stress sites. Specifically, the liquid is injected from the liquid injection device 52 into the hollow portion of the cylindrical portion 24, it is plane deformed toward the second deforming portion 34 by hydraulic pressure recess 45D of the upper die 45. In other words, out-of-plane deformation of the high residual stress of the second deformation portion 34 is deformed into a concave shape by applying a pressure (fluid pressure) in the closed plane that constitutes the tubular portion 24 sites to extravascular direction.
　At this time, while applying a fluid pressure to the hollow portion of the intermediate molded article 21, the compressor 54 compresses the cylindrical portion 24 in the axial direction. In other words, the axial pressing the tubular portion 24 by the compressor 54.
[0041]
　As described above, the residual tensile stress is high site within a vessel surface I of the second deformation portion 34 is out-of-plane deformation to the press direction opposite, i.e., by returning the bending, the inner surface I of the second deformation portion 34 it is possible to generate a compressive stress.
[0042]
　After the hydroforming of the intermediate molded article is completed, removing the liquid from the hollow portion of the intermediate molded article 21. Further, to stop the operation of the compressor 54. Thereafter, as shown in FIG. 16, to raise the upper die 45.
[0043]
　Plastic workpiece hydroforming is completed (torsion beam 22) is caused to spring back due to the rise of the upper mold 45, the stress state of the residual stress is high portion changes as shown in FIG. 17. That is, the inner surface I of the second deformation portion 34, the compressive stress C in the circumferential direction remains.
[0044]
　Next, the operation and effect of this embodiment are described.
[0045]
　First, a description will be given stress distribution in the wall thickness of the automotive part comprising the elastic-plastic material. Figure 25A ~ FIG. 25C, a stress distribution diagram of the torsion beam in Comparative Example 1 where only pressing the hollow tube 20. During bending tensile tube outside surface O as shown in FIG. 25A, flexural compressive stress in the pipe inner surface I is generated, the stress as shown in springback occurs view 25B when the bending load is released is released, the spring after back compressed tube outside surface O as shown in FIG. 25C, the residual tensile stress in the pipe inner surface I is generated. This is a value obtained by subtracting the stress is released by the spring-back of Figure 25B from bending stress Figure 25A. Fatigue properties as described above is deteriorated in this state. Note that symbol C in the figure indicates a compressive stress, symbol T represents a tensile stress.
[0046]
　Therefore the present inventors, as shown in JP-A-2013-91433, after carrying out press working on a hollow tube 20, has developed a technology for applying a tensile force in the circumferential direction. Figure 26A ~ FIG 26C is a stress distribution diagram of the torsion beam in the Comparative Example 2 employing the technique of JP-A-2013-91433, when the deformed tensile force is applied in the circumferential direction hydraulically, as shown in FIG. 26A elastically deformed portion in the wall thickness is plastically deformed tensile residual stresses are all reduced to. Then, the spring-back is stress released as shown in generated view 26B when the user releases the hydraulic pressure, the residual stress of the tube outer surface O and the inner surface of the tube I as shown in Figure 26C becomes zero after spring back. This improves the fatigue characteristics of the torsion beam. But it is rare that a tensile residual stress of the inner surface I is compressed in this way, compressive residual stress is -150MPa about as obtained.
[0047]
　In contrast, in the present embodiment, after performing the pressing in a hollow tube 20, by returning the bending stress changes as shown in FIGS. 27A ~ FIG 27C. Specifically, the elastic deformation part in the thickness as shown in FIG. 27A is tensile residual stress is reduced by plastic deformation. Then, released stress as shown in springback occurs view 27B when the user releases the hydraulic pressure, after springback residual compressive stress in the inner surface I as shown in FIG. 27C. In this case, it is possible to generate a large compressive residual stress of about -300MPa the inner surface I. Therefore, according to the manufacturing method of this embodiment, comparative example 2 or more fatigue properties improvement is obtained.
[0048]
　From the above, in the manufacturing method of this embodiment, in the deformation process, of the closed cross section second deformation portion 34 constitutes, for returning bending high residual stress sites, tensile inner surface of the second deformation portion 34 residual stresses can be reduced. Thus, even without quenching and annealing after the deformation step, it is possible to improve the fatigue properties of the torsion beam 22 to reduce the tensile residual stress of the inner surface I of the second deformation portion 34.
　Particularly to increase the out-of-plane deformation of H out-of-plane deformation portion 28, i.e., by increasing the bending amount of return, the tensile residual stress of the inner surface I of the second deformation portion 34 is zero or a compressive residual stress. By tensile residual stress of the inner surface I of the second deformation portion 34 is compressive residual stress, thereby improving the fatigue characteristics of the torsion beam 22.
[0049]
　In the manufacturing method of this embodiment, the liquid injected from the liquid injection device 52 into the hollow portion of the intermediate molded article 21, the out-of-plane toward the second deformation portion 34 to the recess 45D of the upper die 44 by a hydraulic deforming. Therefore, as compared with the configuration in which the member to project toward the outer tube side of the second deformation portion 34 of the intermediate molded article 21 to the manufacturing apparatus 40 from the tube side, plane with a simple structure (a simple mold shape) it is possible to form the deformed portion 28.
[0050]
　Furthermore, in the manufacturing method of the present embodiment, while applying a fluid pressure to the hollow portion of the intermediate molded article 21, to compress the cylindrical portion 24 in the axial direction by the compressor 54. That is, to implement the hydroforming against the cylindrical portion 24 can be molded of the second deformation portion 34 in a shape along the recessed portion 45D of the upper die 44.
[0051]
　In the manufacturing apparatus 40 of the present embodiment, the press section 44A of the upper die 44 has a movable structure in the pressing direction, it is not limited to this configuration. The upper mold 45 may be an integral finished product. In this configuration, it is possible to omit the pressure device 51.
[0052]
　In the production method of the present embodiment, in the deformation process, while applying a fluid pressure to the hollow portion of the intermediate molded article 21 has a configuration to compress the intermediate molded article 21 in the axial direction by the compression device 54, limited to this structure not. Intermediate product 21 in the hollow portion only the configuration for applying a fluid pressure toward the second deforming portion 34 a recess 45D is out-of-plane deformation of the (back bend) may be configured.
[0053]
　According to the present disclosure, the unbending of sites bent back, often on the order of a shape tube surface is plastically deformed, the height is about approximate thickness half. In this case, it is not deteriorated fatigue properties like load of stress concentration. Although the tensile residual stress on the tube outer surface of the site that returned the bending occurs, the stress generated at the torsion beam load larger towards the inner surface, the fatigue characteristics even slight residual tensile stress in the tube outer surface is generated does not deteriorate .
[0054]
　Further, in the present disclosure, the torsion beam 22 to generate a compressive residual stress to the inner surface I, and from the viewpoint of avoiding stress concentration at the time of the torsion beam load, the deformation amount of out-of-plane deformation portion 28 H, the out-of-plane deformation portion 28 the radius of curvature R may be less than. Where t is the thickness of the hollow tube.
　　H ≦
　　5t (the t thickness of the hollow tube) 0.5 t ≦ R ≦ 10t
　More preferably, plane deformation amount H out-of-plane deformation portion 28, as follows the curvature radius R of the out-of-plane deformation portion 28 Then good.
　　≦
　　T H 2T ≦ R ≦ 5T
[0055]
[Second Embodiment]
　Hereinafter, a method for manufacturing automobile parts of the second embodiment (hereinafter abbreviated to as "manufacturing method".) Will be described. Note that the same components as the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
　First, describes automobile part produced by the production method of this embodiment, it will be described the manufacturing apparatus used in the method of the present embodiment. Then, a method for manufacturing the present embodiment.
[0056]

　torsion beam 72 as shown in FIGS. 23 and 24, for the same configuration as that of the torsion beam 22 of the first embodiment except for the configuration of the torsion portion 26 which is formed in plane deformation portion 74, description thereof will be omitted.
[0057]
(Out-of-plane deformation portion 74)
　out-of-plane deformation portion 74 is a concave part obtained by out-of-plane deformation such that the concave of the second deformation portion 34 is deformed in a concave shape from the pipe outer side to the tube side.
[0058]

　Next, a description will be given of a manufacturing apparatus for an automobile parts of the present embodiment.
　As shown in FIGS. 6A and 18, the manufacturing apparatus 76, after forming the intermediate product a hollow tube 20 by pressing a device for forming the torsion beam 72 by hydroforming. Manufacturing apparatus 76 includes an upper mold 44 and lower mold 46 for molding the intermediate molded article 21 a portion of the hollow tube 20 by pressing. The configuration of the upper mold 44 and the lower mold is the same as those in the first embodiment, the description thereof is omitted.
[0059]
　Manufacturing apparatus 76 is provided with upper mold 80 for molding the out-of-plane deformation portion 74 to be described later bent back the second deformation portion 34 by hydroforming.
[0060]
　Upper mold 80 has a pressing portion 80A to deform and pressed toward a portion of the hollow tube 20 (the upper portion in FIG. 18) from the pipe outer side into the tube side, V-shaped open end of the torsion portion 26 recess 80B for molding and a molding portion 80C formed a. Incidentally, the upper die 80 of the present embodiment, the press section 80A is movable in the pressing direction (arrow P) on the molding portion 80C.
[0061]
　In addition, the press section 80A, projections 80D are formed at a position corresponding to the out-of-plane deformation portion 74 of the torsion portion 26.
[0062]
　The manufacturing apparatus 76 includes a moving device 49 for relatively moving the upper mold 80 and the lower mold 46, and a pressure device 51 for moving the press section 80A in the pressing direction. The moving device 49 and the pressure device 51, for the same configuration as the first embodiment, the description thereof is omitted.
[0063]
　The manufacturing apparatus 76 is in a state of pressing the cylindrical portion 24 in the upper mold 80 and the lower mold 46, the liquid injection apparatus 52 for injecting a liquid into the hollow portion of the intermediate molded article 21, intermediate molded article 21 the compression in the axial direction (so-called pressing axis) includes a compressor 54, a. The liquid injection device 52 and the compression device 54, for the same configuration as the first embodiment, the description thereof is omitted.
[0064]

　Next, a method for manufacturing the automobile parts of the present embodiment.
　Incidentally, the cylindrical portion 24 of the hollow tube 20, for the first setting step and a molding step of setting the concave portion 46A of the lower die 46 of the manufacturing apparatus 76, the same as those in the first embodiment, the description thereof is omitted .
[0065]
　(Second setting step)
　Next, as shown in FIG. 18, while leaving the intermediate product in the recess 46A of the lower die 46, replacing the upper mold 44 and upper mold 80. Thereafter, by operating the moving device 49 lowers the upper die 80. Then, set the intermediate product into a cavity formed between the upper mold 80 and the lower mold 46 (see FIGS. 19 and 20). At this time, the second deformation portion 34 of the intermediate molded article 21 is pressed by the projection 80D of the press section 80A.
[0066]
(Deformation step)
　Next, as shown in FIGS. 21 and 22, of the closed cross section second deforming portion 34 of the intermediate molded article 21 is configured, to out-of-plane deformation of the high residual stress sites. Specifically, the liquid is injected from the liquid injection device 52 into the hollow portion of the intermediate molded article 21, the second deformation portion 34 is deformed into a concave shape of the cylindrical portion 24 by hydraulic pressure protrusion 80D around the press section 80A is out-of-plane deformation toward. In other words, out-of-plane deformation of the high residual stress sites of the second deformation portion 34 by applying a pressure (fluid pressure) in the closed plane that constitutes the second deformation portion 34 into the tube side.
　At this time, while applying a fluid pressure to the hollow portion of the intermediate molded article 21, to compress the intermediate molded article 21 in the axial direction by the compressor 54. In other words, the axial pressing the tubular portion 24 by the compressor 54.
[0067]
　As described above, the residual tensile stress is high site within a vessel surface I of the second deformation portion 34 is out-of-plane deformation to the press direction opposite, i.e., by returning the bending, the inner surface I of the second deformation portion 34 tensile residual stress can be reduced.
[0068]
　After the hydroforming of the intermediate molded article is completed, removing the liquid from the hollow portion of the intermediate molded article 21. Further, to stop the operation of the compressor. Thereafter, as shown in FIG. 22, to raise the upper die 45.
[0069]
　In the second embodiment, except for the effect of the mold shape of the first embodiment simply, it is possible to obtain the same effects as the first embodiment.
[0070]
　Examples of the present disclosure below.
Example
[0071]
　Using electric resistance welded steel pipe as a hollow tube, to process the hollow tube to the torsion beam by the manufacturing method of the present disclosure. Then, we examined whether can satisfy the fatigue properties of the torsion beam without heat treatment. To satisfy the fatigue properties of the torsion beam without heat treatment, it is necessary that the residual stress in the inner surface of the tube than -300 MPa.
[0072]
　Therefore, processed into torsion beam blank tube as shown in Table 1 (hollow tube) by a plurality of processing conditions, the wall thickness reduction rate for site residual stress of the torsion beam is high, the maximum residual stress, surface portion residual stress load at the time examined the generated stress. As a result, as shown in Table 1, none of the embodiments of the present disclosure is the maximum residual stress is reduced compared with Comparative Example, and the surface layer portion the residual stress becomes smaller than -300 MPa. The stress generated at the time of the load and the wall thickness reduction rate was almost the same. From the above, it was revealed that satisfies the fatigue strength of the torsion beam without heat treatment according to the present disclosure. For reference, the analytical model of the conditions 1 shown in Table 1 in FIG. 28 shows an analysis model of the conditions 11 in Figure 29.
[0073]
[Table 1]

[0074]
　Incidentally, 0.5t ≦ H ≦ 5t, t ≦ R ≦ 10t (t is the wall thickness of the hollow tube) if, can grant reliably compressive residual stress in the surface portion, and load the generated stress is increased it can reduce the residual stress rather preferred for improvement of fatigue characteristics.
[0075]
　As described above, according to the method of manufacturing automobile parts of the hollow tube of the present disclosure, without the need for quenching or annealing after molding, suitable for use as such as a torsion beam for a motor vehicle, the fatigue properties it can be produced an improved automotive parts were. The manufacturing method for automobile parts of the present disclosure is not intended to be limited to the manufacturing method of the torsion beam, it can of course be widely applied to automobile parts other than torsion beam.
[0076]
　Relates above embodiments, the following additional statements are further disclosed.
[0077]
　　(Supplementary Note 1)
　is deformed beyond said hollow tube axis from the pipe outer side into the tube side by pressing part of the hollow tube formed by a composite material comprising a metal material or a metal and a resin, a shaping step of shaping the deformed portion partially deformed into a concave shape of the hollow tube,
　of the closed cross section the deformable portion constitutes a high residual stress sites to out-of-plane deformation, and deformation step,
　automobile comprising manufacturing method of use parts.
[0078]
　　(Supplementary Note 2)
　In the above modification step, the out-of-plane deformation of the high deformation portion is the residual stress by applying a pressure to the closed plane constituting part into extravascular direction, the manufacture of automotive parts according to Appendix 1 Method.
[0079]
　　(Supplementary Note 3)
　The in deforming step, while applying a pressure to the closed plane of the flexible portion is configured to compress said hollow tube axially method for manufacturing automobile parts according to Appendix 2.
[0080]
　　(Supplementary Note 4)
　In the above modification step, the out-of-plane deforming the high residual stress sites closed cross section deformation portion is composed of an extravascular direction to push to the tube side, the manufacture of automotive parts according to Appendix 1 Method.
[0081]
　　(Supplementary Note 5)
　The in deforming step, while pressing the highly the residual stress of the closed cross section the deformable portion constitutes part into the tube side, compressing the hollow tube in the axial direction, automotive according to Appendix 4 method of manufacturing the parts.
[0082]
　　(Supplementary Note 6)
　The amount of deformation is out-of-plane deformation of the high portion of the residual stress of the closed cross section the deformable portion constitutes H, the radius of curvature of the portion that is out-of-plane deformation R, the thickness of the hollow tube t when a satisfies 0.5t ≦ H ≦ 5t a and t ≦ R ≦ 10t, method of manufacturing automotive component according to any one of appendices 1 to Appendix 5.
[0083]
　　(Supplementary Note 7)
　the flexible portion has a first deformation portion which is deformed beyond the axis of the hollow tube from the pipe outer side into the tube side of a portion of the hollow tube by pressing the first variant part and connects with other parts of the hollow tube, and a second deformation portion which deformation amount toward the said another portion into the first deformation portion is changed gradually, has,
　in the deforming step, the first 2 deformable portion is out-of-plane deformation of the high portion the residual stress of the closed cross section constituting, automobile parts manufacturing method according to any one of appendices 1 to Appendix 6.
[0084]
　　(Supplementary Note 8)
　the hollow tube, used in a suspension apparatus of a vehicle, closed cross section the first deformable portion constitutes the V-processed into the torsion beam, which is a U-shaped or C-shaped, Appendix 7 automobile parts manufacturing method described.
[0085]
　　(Supplementary Note 9)
　　and a cylindrical portion formed by a composite material comprising a metal material or a metal and a resin,
　is provided axially outwardly of the tubular portion, the tube outer part of the peripheral wall with respect to the tubular portion a first deformation portion which is deformed in a concave shape across the axis of the tubular portion into the tube side from the side,
　connects with the cylindrical portion and the first deformable portion, toward from the tubular portion to the first deforming portion a second deformation portion which the deformation is gradually changed Te, a deformable portion having,
　in a closed cross section perpendicular to the axial direction of the tubular portion of the second deformation portion, respectively formed in a portion opposed to each other convex Jo or a concave plane deformation portion,
　automobile parts comprising a.
[0086]
　　(Supplementary Note 10)
　used in a suspension apparatus of a vehicle, the first deformable portion constitutes closed section V-shape, a torsion beam, which is a U-shaped or C-shaped, automobile parts according to Appendix 9.
[0087]
　　(Supplementary Note 11)
　in a hollow tube made of a composite material made of a metal material or a metal and a resin, a process for the preparation of automobile parts molded giving displacement directed from the outside inward,
　the hollow tube and a molded portion which is displaced towards the outside inward to the cylindrical portion,
　of the closed cross section the molded part is configured, by out-of-plane deformation of the high residual stress sites in the opposite direction, of the forming section method for producing automotive parts, characterized in that to reduce the residual stresses.
[0088]
　　(Supplementary Note 12)
　In order to impart the surface outer deformation to the molded portion, pressurizing the inside of the closed section formed by the forming unit by a gap outside the high target site of said residual stress automobile parts manufacturing method of statement 11, wherein the.
[0089]
　　(Supplementary Note 13)
　In order to impart the surface outer deformation to the molded part, a gap is provided outside of the high target site of said residual stress, pressure to the inside of the formed closed section by the molding section pressure while, automotive parts manufacturing method of statement 11, characterized by axial pressing the material from the tube end of the forming section.
[0090]
　　(Supplementary Note 14)
　In order to impart the surface outer deformation with respect to the molding unit, a pressurizing the inside of the closed section formed by the forming unit by pushing the high target site of said residual stress inwardly method for manufacturing automobile parts according to note 11, wherein.
[0091]
　　(Supplementary Note 15)
　In order to impart the surface outer deformation to the molded part, while pressurizing the inside of the formed closed section by the molding unit by pushing the high target site of said residual stress inwardly, automobile parts manufacturing method of statement 11, characterized by axial pressing the material from the tube end of the forming section.
[0092]
　　(Supplementary Note 16)
　automobile parts of the hollow tube, connects the right and left arms in a suspension device, in a cross section perpendicular to the width direction of the vehicle body, is a torsion beam which is a V-shaped or U-shaped closed cross-section Supplementary note 11 to Supplementary note 15 any one automobile part manufacturing method according to, characterized in that.
[0093]
　In this case, in the V-shaped or U-shaped closed cross section, in order to out-of-plane deformation of the high residual stress sites in the reverse direction, the V-shaped or U-shaped are subject to fatigue strength improvement providing a gap outside the closed section, it is possible to pressurize the inside of the closed section. Further, in order to impart a circumferential tensile stress in the V-shaped or U-shaped closed cross-section, the gap to the outside of the V-shaped or U-shaped closed cross-section is subject to fatigue strength improvement provided, while pressurizing the inside of the closed section, the material can be pushed axis from the pipe end of the forming section.
[0094]
　　(Supplementary Note 17)
　In the V-shaped or U-shaped closed cross section, in order to out-of-plane deformation of the high residual stress sites in the reverse direction, the V-shaped or U-shaped are subject to fatigue strength improvement a gap is provided outside of the closed section, automobile parts manufacturing method of statement 16, wherein the pressurizing inside of the closed section.
[0095]
　　(Supplementary Note 18)
　to impart a circumferential tensile stress in the V-shaped or U-shaped closed cross-section, the outside of the V-shaped or U-shaped closed cross-section is subject to fatigue strength improvement and a clearance, the while pressurizing the inside of the closed section, automobile parts manufacturing method of statement 16, characterized by axial pressing the material from the tube end of the forming section.
[0096]
　　(Supplementary Note 19)
　In the V-shaped or shaped closed cross section, in order to out-of-plane deformation of the high residual stress sites in the reverse direction, the V-shaped or U-shaped closed are subject to fatigue strength improvement push the cross section inwardly, automobile parts manufacturing method of statement 16, wherein the pressurizing inside of the closed section.
[0097]
　　(Supplementary Note 20)
　to impart a circumferential tensile stress in the V-shaped or U-shaped closed cross-section, the V-shaped or U-shaped closed cross-section inward is the subject of improving fatigue strength pushed by the while pressurizing the inside of the closed section, automobile parts manufacturing method of statement 16, characterized by axial pressing the material from the tube end of the forming section.
[0098]
　According to the manufacturing method according to Supplementary Note 11 to Supplementary Note 20 automotive parts can be reduced circumferential tensile residual stress distribution in the thickness direction of the molded part (compression and tensile stress). As a result, it is possible to improve the fatigue strength of the product. It is possible to generate a large compressive residual stress to a further tube surface, it is possible to further improve fatigue strength. With particular application of the present disclosure in the production method of the torsion beam can be improved the fatigue properties.
[0099]
　Incidentally, disclosure of Japanese Patent Application No. 2016-046898 filed on March 10, 2016, the entirety of which is incorporated herein by reference.
　All documents described herein, patent applications, and technical standards, each individual publication, patent application, and that the technical specification is incorporated by reference to the same extent as if marked specifically and individually, It incorporated by reference herein.

The scope of the claims
[Requested item 1]
　Some of the hollow tube formed by a composite material comprising a metal material or a metal and resin to deform beyond the axis of the hollow tube from the pipe outer side into the tube side by pressing, said hollow tube a forming step in which a part of forming the deformed portion which is deformed into a concave shape,
　of closed cross section the deformable portion is configured, to out-of-plane deformation of the high residual stresses sites, and deforming step,
　the production of automobile parts including a Method.
[Requested item 2]
　And in the deformation step, the out-of-plane deformation of the high the deformable portion by applying a pressure in a closed cross section which constitutes the residual stress sites to extravascular direction, a manufacturing method of an automotive part according to claim 1.
[Requested item 3]
　Wherein in deforming step, while applying a pressure to the closed plane of the flexible portion is configured to compress said hollow tube axially, automobile parts manufacturing method according to claim 2.
[Requested item 4]
　And in the deformation step, the out-of-plane deforming the high residual stress sites closed cross section deformation portion is composed of an extravascular direction to push to the tube side, a manufacturing method of an automotive part according to claim 1.
[Requested item 5]
　Wherein in deforming step, while pressing the high part of the residual stress of the closed cross section the deformable portion is configured into the tube side, compressing the hollow tube in the axial direction, the manufacture of automotive parts according to claim 4 Method.
[Requested item 6]
　When the amount of deformation is out-of-plane deformation of the high portion of the residual stress of the closed cross section the deformable portion constitutes H, the radius of curvature of the portion that is out-of-plane deformation and R, the wall thickness of the hollow tube and t, satisfy 0.5t ≦ H ≦ 5t a and t ≦ R ≦ 10t, automobile parts manufacturing method according to any one of claims 1 to 5.
[Requested item 7]
　The deformable portion includes a first deformation portion which is deformed beyond the axis of the hollow tube from the pipe outer side into the tube side of a portion of the hollow tube by press working, in the said first deformable section connects with the rest of the empty tubes, and a second deformation portion which deformation amount toward the first deformation portion from the other portion is gradually changed, has,
　the in deforming step, the second deforming portion is is out-of-plane deformation of the high portion of the residual stress of the closed cross section constituting, automobile parts manufacturing method according to any one of claims 1 to 6.
[Requested item 8]
　Said hollow tube, used in a suspension apparatus of a vehicle, the closed section V-shaped first deforming portion is configured to process the torsion beam, which is a U-shaped or C-shaped, according to claim 7 method of manufacturing automotive parts.
[Requested item 9]
　A cylindrical portion formed by a composite material comprising a metal material or a metal and a resin,
　is provided on one side in the axial direction of the cylindrical portion, part of the peripheral wall from an extravascular direction relative to the tubular portion a first deformation portion which is deformed in a concave shape to the tube side beyond the axis of the cylindrical portion,
　connecting with said tubular portion and the first deformation portion, deformation toward the first deformation portion from the cylindrical portion a deformation portion having a second deformation portion which amount is gradually changed, and
　the closed cross section perpendicular to the axial direction of the tubular portion of the second deformable portion, convex or respectively formed in a portion opposed to each other and concave plane deformation portion,
　automobile parts comprising a.
[Requested item 10]
　Used in a suspension apparatus of a vehicle, the first deformable portion constitutes closed section V-shape, a torsion beam, which is a U-shaped or C-shaped, automobile part according to claim 9.