JP5560569B2 - Wheel bearing device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wheel bearing device and a manufacturing method thereof.

In the wheel bearing device, a shaft portion to which the rolling bearing is assembled, a fitting shaft portion formed at one end of the shaft portion and having a larger diameter than the shaft portion and into which the center hole of the wheel is fitted, a shaft portion, A flanged shaft member having a plurality of flange portions extending radially outwardly on the outer peripheral surface located between the fitting shaft portions and through which bolt holes in which hub bolts for tightening the wheels are arranged are penetrated ( Some have a structure with a hub wheel).
A wheel bearing device having such a structure is disclosed in Patent Document 1, for example.
In this, a flanged shaft member (hub wheel) is shaped by cold forging using a cylindrical tube as a base material, and a plurality of circumferential directions at one shaft end of the cold forged base material are in the radial direction. A plurality of flange portions (cut-and-raised pieces) are formed by being cut and raised outward. Further, a fitting shaft portion (a wheel is fitted and positioned) formed of a plurality of tongue pieces remaining in a shape along the axial direction between the plurality of flange portions at one shaft end portion of the base material. Is provided.

JP 2003-25803 A

By the way, in the conventional wheel bearing device as disclosed in Patent Document 1, a plurality of flanges formed by cutting and raising pieces at one shaft end of a forged product shaped by cold forging using a cylindrical tube as a base material. A part is formed and a shaft member with a flange is constituted.
This makes it possible to reduce the weight of the wheel bearing device (mainly a shaft member with a flange).
However, in the conventional wheel bearing device, after manufacturing a forged product by cold forging, one shaft end portion of the forged product must be bent and raised to form a plurality of flange portions. However, the manufacturing cost increases with the bending process.
The flange portion is formed by cutting and raising the cylindrical tube by bending, and the bent portion of the flange portion corresponds to the thick portion of the cylindrical tube. In order to increase the strength in the vicinity of the root portions of the plurality of flange portions, it is difficult to form a shape in which only the root portions are thickened.

  Thus, the present invention was devised in view of such a point, and the problem to be solved by the present invention is to reduce the manufacturing cost while reducing the weight, It is to provide a wheel bearing device and a method for manufacturing the same that can increase the strength in the vicinity of the root portion of the flange portion while ensuring the formability of the forging side extrusion.

In order to solve the above problems, the wheel bearing device of the present invention takes the following means.
First, a wheel bearing device according to a first aspect of the present invention includes a shaft portion to which a rolling bearing is assembled, a fitting shaft portion formed on one end side of the shaft portion and into which a center hole of the wheel is fitted, and the shaft portion. And a flange having a plurality of flange portions extending radially in an outer radial direction and having bolt holes through which hub bolts for tightening the wheels are disposed. A bearing device for a wheel including a shaft member, wherein the flange portion is formed when a forged recess is formed in a center end face of the fitting shaft portion by cold forging, and the shaft portion and the fitting shaft portion. Are formed by lateral extrusion radially extending in the outer diameter direction on the outer peripheral surface located between the fitting shaft portion and the peripheral portion excluding the axial region where the flange portion is formed. It is formed in the direction position, distribution between adjacent flange position By Rukoto it is configured to be formed, with repeated stress due to repeated load from the wheels prevented from concentrating on the flange root portion, fitting shaft portion, the flange portion side extrusion cold forging It is characterized by being formed simultaneously with.

According to the first aspect of the present invention, weight reduction is achieved by forming a plurality of flange portions radially on the outer peripheral surface located between the shaft portion and the fitting shaft portion by a side extrusion process of cold forging. However, the manufacturing cost can be reduced.
Further, the flange portion of the wheel bearing device is a portion to which the wheel is attached. A load from the wheel is repeatedly applied, and repeated stress is generated in the vicinity of the root portion of the flange portion.
If the fitting shaft portion is formed in the axial region of the position where the flange portion is formed, there is a risk that stress repeatedly concentrates on the flange portion and the corner of the fitting shaft portion (the base portion of the flange portion). is there.
Therefore, the fitting shaft portion is configured not to be formed in the axial region of the position where the flange portion is formed, thereby preventing the repeated stress accompanying the repeated load from the wheel from concentrating on the flange root portion. . In addition, since the fitting shaft portion is formed at a position between the adjacent flanges by being formed at a circumferential position excluding an axial region of the position where the flange portion is formed, the center of the wheel The function of fitting the hole is not impaired.
Further, the flanged shaft member receives a large compressive force at the time of cold forging forming, whereby the mechanical properties of the material after forming can be changed and surface hardening can be obtained, so that the strength can be improved. . Further, since the fitting shaft portion is not formed in the axial region of the position where the flange portion is formed, the weight of this portion can be reduced, and a turning process for removing the portion after molding becomes unnecessary, Manufacturing costs can be reduced.
Moreover, in the side extrusion process of cold forging, the fitting shaft portion is not formed in the axial direction region where the flange portion is formed. Therefore, the fluidity of the material in forming the flange portion can be ensured, and the formability of the side extrusion process of cold forging can be ensured.

Next, a method for manufacturing a wheel bearing device according to a second aspect of the present invention includes: a shaft portion on which a rolling bearing is assembled; a fitting shaft portion formed on one end side of the shaft portion and fitted with a center hole of the wheel; And a plurality of flange portions which are located between the shaft portion and the fitting shaft portion and extend radially in the outer diameter direction and through which bolt holes are disposed in which hub bolts for tightening the wheel are disposed. A method of manufacturing a wheel bearing device including a shaft member with a flange, wherein the shaft portion is formed by forming a forged recess in a central end face of the fitting shaft portion by a cold forging forging die device having a punch. A flange portion forming step for forming the flange portion by lateral extrusion extending radially outwardly on the outer peripheral surface between the fitting shaft portion and the fitting shaft portion; Position in the circumferential direction excluding the axial region A fitting shaft portion forming step of arranging and forming the fitting shaft portion between adjacent flanges, and performing both the flange portion forming step and the fitting shaft portion forming step as the same step. The punch provided in the cold forging die forging die device has a flange corresponding to the number of the flange portions at a position corresponding to the formation region of the flange portion as seen in the axial section of the fitting shaft portion. A protruding portion that protrudes in the direction of side extrusion of the portion is formed, and the protruding portion is formed to have the same width as the flange width of the flange portion, and to the same outer diameter as the outer diameter of the fitting shaft portion. At the same time that the flange portion is formed by using the punch, a fitting shaft portion is formed at a circumferential position excluding the formation region of the flange portion, and the fitting is performed between adjacent flanges. The shaft portion is arranged and formed.

According to the second aspect, the wheel bearing device according to the first aspect can be easily manufactured.
Further, the punch provided in the cold forging die forging device is viewed from the axial cross section of the fitting shaft portion, at a position corresponding to the formation region of the flange portion, on the side of the flange portion corresponding to the number of flange portions. A protrusion that protrudes in the extrusion direction is formed. The protruding portion is formed to have the same width as the flange width of the flange portion, and is formed to protrude to the same outer diameter as the outer diameter of the fitting shaft portion. By using this punch, at the same time as forming the flange portion, the fitting shaft portion is formed at a circumferential position excluding the formation region of the flange portion, and the fitting shaft portion is disposed and formed between adjacent flanges. It has a configuration that can. Since the formation of the flange portion and the formation of the fitting shaft portion are processed in the same process, the manufacturing cost can be reduced.
Further, since the fitting shaft portion is not formed in the axial direction region where the flange portion is formed, the weight of this portion can be reduced. Further, there is no need for a turning process for deleting the portion after molding, and the manufacturing cost can be reduced.

  Next, in the method for manufacturing a wheel bearing device according to the third invention, in the second invention, the structure of the protrusion provided in the punch provided in the forging die device for cold forging is formed in the punch. Instead, it is formed in a forming die provided in the forging die device of the cold forging, and the forming die is formed in the formation region of the flange portion when viewed in the axial section of the fitting shaft portion. In the corresponding position, there is formed a protruding portion that protrudes in the center direction of the fitting shaft portion corresponding to the number of the flange portions, and the protruding portion is formed with the same width as the flange width of the flange portion. And is formed so as to protrude to the same inner diameter as the inner diameter of the fitting shaft portion, and at the same time as the flange portion is formed using the molding die, at the same time in a circumferential position excluding the formation region of the flange portion. Form a fitting shaft, and place the fitting shaft between adjacent flanges. Characterized by location formed.

According to the third invention, the wheel bearing device described in the first invention can be easily manufactured.
In addition, the configuration of the protrusion provided on the punch included in the forging die device for cold forging is changed to that formed on the punch, and in the configuration formed on the forming die included in the forging die device for cold forging. Can also be achieved.

The present invention can obtain the following effects by taking the measures of the above inventions.
First, according to the wheel bearing device of the first aspect of the present invention, a plurality of flange portions are radially formed on the outer peripheral surface located between the shaft portion and the fitting shaft portion by a side extrusion process of cold forging. Thus, the manufacturing cost can be reduced while reducing the weight.
Further, the flange portion of the wheel bearing device is a portion to which the wheel is attached. A load from the wheel is repeatedly applied, and repeated stress is generated in the vicinity of the root portion of the flange portion.
If the fitting shaft portion is formed in the axial region of the position where the flange portion is formed, there is a risk that stress repeatedly concentrates on the flange portion and the corner of the fitting shaft portion (the base portion of the flange portion). is there.
Therefore, the fitting shaft portion is configured not to be formed in the axial region of the position where the flange portion is formed, thereby preventing the repeated stress accompanying the repeated load from the wheel from concentrating on the flange root portion. . In addition, since the fitting shaft portion is formed at a position between the adjacent flanges by being formed at a circumferential position excluding an axial region of the position where the flange portion is formed, the center of the wheel The function of fitting the hole is not impaired.
Further, the flanged shaft member receives a large compressive force at the time of cold forging forming, whereby the mechanical properties of the material after forming can be changed and surface hardening can be obtained, so that the strength can be improved. . Further, since the fitting shaft portion is not formed in the axial region of the position where the flange portion is formed, the weight of this portion can be reduced, and a turning process for removing the portion after molding becomes unnecessary, Manufacturing costs can be reduced.
Moreover, in the side extrusion process of cold forging, the fitting shaft portion is not formed in the axial direction region where the flange portion is formed. Therefore, the fluidity of the material in forming the flange portion can be ensured, and the formability of the side extrusion process of cold forging can be ensured.

Next, according to the method for manufacturing a wheel bearing device according to the second invention, the wheel bearing device according to the first invention can be easily manufactured.
Further, the punch provided in the cold forging die forging device is viewed from the axial cross section of the fitting shaft portion, at a position corresponding to the formation region of the flange portion, on the side of the flange portion corresponding to the number of flange portions. A protrusion that protrudes in the extrusion direction is formed. The protruding portion is formed to have the same width as the flange width of the flange portion, and is formed to protrude to the same outer diameter as the outer diameter of the fitting shaft portion. By using this punch, at the same time as forming the flange portion, the fitting shaft portion is formed at a circumferential position excluding the formation region of the flange portion, and the fitting shaft portion is disposed and formed between adjacent flanges. It has a configuration that can. Manufacturing costs can be reduced due to processing in the same process.
Further, since the fitting shaft portion is not formed in the axial direction region where the flange portion is formed, the weight of this portion can be reduced. Further, there is no need for a turning process for deleting the portion after molding, and the manufacturing cost can be reduced.
Next, according to the method for manufacturing the wheel bearing device according to the third invention, the wheel bearing device according to the first invention can be easily manufactured.
In addition, the configuration of the protrusion provided on the punch included in the forging die device for cold forging is changed to that formed on the punch, and in the configuration formed on the forming die included in the forging die device for cold forging. Can also be achieved.

It is a longitudinal cross-sectional view which shows the wheel bearing apparatus which concerns on Example 1 of this invention. It is a longitudinal section showing a shaft member with a flange similarly. It is a top view which similarly shows the shaft member with a flange from the fitting shaft part side. It is explanatory drawing which similarly shows the manufacturing process of a shaft member with a flange. It is a longitudinal cross-sectional view which shows the state which the primary molded product was set in the cavity of both the 1st and 2nd shaping | molding die of a cold forging similarly, and the mold was closed. It is a longitudinal cross-sectional view which shows the state which forms a some flange part by a side extrusion process, forming a forge recessed part in the end surface of the fitting shaft part of a primary molded product similarly. It is the longitudinal cross-sectional view which expands and similarly shows the flange molding part of the cavity of both the 1st and 2nd shaping | molding die. It is a longitudinal cross-sectional view which expands and shows the flange molding part of the cavity of both the 1st and 2nd shaping | molding die of Example 2 of this invention. Similarly, it is a longitudinal sectional view showing, in an enlarged manner, a flange molding portion of a cavity of both the first and second molding dies according to Embodiment 3 of the present invention. It is the perspective view which showed the external shape of the punch comprised in the forging die apparatus of the side extrusion process of cold forging. Similarly, it is a longitudinal sectional view showing a state where the primary molded product is set in the cavities of both the first and second molding dies of Example 4 of the present invention and the mold is closed. It is a longitudinal cross-sectional view which shows the state which forms a some flange part by a side extrusion process, similarly forming the forge recessed part in the end surface of the fitting shaft part of a primary molded product with the punch of Example 4 of this invention. It is a perspective view which similarly shows a shaft member with a flange.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, a wheel bearing device according to a first embodiment of the present invention will be described with reference to FIGS.
1, each of the sectional views of the shaft member with a flange (hub wheel) in FIGS. 2, 4 to 6, 11, and 12 is a cross section showing a flange forming portion and a non-sectional view. In order to illustrate the flange portion forming portion (the position where the flange portion 21 is not formed in the forged recess 33), it is illustrated as a cross-sectional view taken along line AA when viewed in the axial section of the fitting shaft portion 30 in FIG. Yes.
As shown in FIG. 1, a wheel hub unit as a wheel bearing device is a unit having a flanged shaft member (hub wheel) 1 and a double row angular ball bearing 41 as a rolling bearing. It has become.
The flanged shaft member 1 includes a shaft portion 10 on which a double-row angular ball bearing 41 as a rolling bearing is assembled on an outer peripheral surface, a wheel formed on one end side of the shaft portion 10 and having a larger diameter than the shaft portion 10 ( A fitting shaft portion 30 into which a center hole (not shown) is fitted, a flange base portion 20a positioned between the shaft portion 10 and the fitting shaft portion 30, and a radially outer surface on the outer peripheral surface of the flange base portion 20a. And a plurality of flange portions 21 each having a bolt hole 24 in which a hub bolt 27 for tightening a wheel is disposed by press-fitting.
Further, as will be described later, the fitting shaft portion 30 has a fitting wall thickness for fitting a wheel center hole at a circumferential position excluding an axial region where the flange portion 21 is formed. The flat part 410 in which the fitting thickness part 400 is not formed is formed in the circumferential position (flange part 21 formation position) where the part 400 is formed and the flange part 21 is formed. The fitting thick part 400 and the flat part 410 are alternately arranged and formed (staggered arrangement) in the circumferential direction of the fitting shaft part 30.
In the fitting thick part 400, the brake rotor fitting part 31 is formed on the flange part 21 side, and the wheel fitting part 32 having a slightly smaller diameter than the brake rotor fitting part 31 is formed on the tip side. Has been.

In the first embodiment, an outer ring member 45 is disposed on the outer peripheral surface of the shaft portion 10 of the flanged shaft member 1 while maintaining an annular gap, and a predetermined interval is maintained in the axial direction of the inner peripheral surface of the outer ring member 45. A plurality of balls 50 and 51 as rolling elements are held by the cages 52 and 53 between the formed raceway surfaces 46 and 47 and the raceway surfaces 43 and 44 on the shaft portion 10 side, respectively. Thus, the double-row angular ball bearing 41 is configured.
In the first embodiment, the shaft portion 10 of the shaft member 1 with the flange is formed in a stepped shaft shape in which the flange portion 21 side has a large diameter and the distal end side has a small diameter, and the shaft portion 10 has a large diameter portion 11. One raceway surface 43 is formed on the outer peripheral surface.
An inner ring body 42 is fitted on the outer peripheral surface of the small diameter portion 12 of the shaft portion 10, and the other raceway surface 44 is formed on the outer peripheral surface of the inner ring body 42.
Furthermore, an end shaft portion 15 having the same diameter as that of the small diameter portion 12 extends from the tip portion of the shaft portion 10. A shaft end concave portion 16 is formed in the center of the end surface of the end shaft portion 15, and a distal end portion of the end shaft portion 15 is caulked radially outward to form a caulking portion 17, thereby forming an outer peripheral surface of the small diameter portion 12. The inner ring body 42 is fixed to.

  A vehicle body side flange 48 is integrally formed at the axial center of the outer peripheral surface of the outer ring member 45, and the wheel hub unit includes a vehicle body side member such as a vehicle suspension device (not shown). The knuckle supported by (3) or the mounting surface of the carrier is connected by a bolt.

As shown in FIG. 2 and FIG. 3, the plurality of flange portions 21 of the shaft member 1 with flange are laterally extruded when a forged recess 33 is formed on the end face of the center portion of the fitting shaft portion 30 by cold forging. Formed by. In addition, on the base portion (base portion) of the flange portion 21 and one side thereof (hereinafter simply referred to as the vicinity of the root portion) (the side that becomes the vehicle inner side surface when the rotor support surface 22 of the flange portion 21 is the vehicle outer side surface) A thick portion 23 is formed that protrudes toward the inside of the vehicle.
Further, the thick portion 23 is formed in an inclined shape that gradually decreases from the base portion (base portion) side of the flange portion 21 toward the bolt hole 24 side of the flange portion 21. The inclination angle of the inclined surface 23a of the thick wall portion 23 (the angle with respect to the annular flat surface 23c orthogonal to the rotation center line S of the flanged shaft member 1) θ1 is the material flow during cold forging and demolding after forming. In view of the above, it is desirable to set the relationship 20 ° ≦ θ1 ≦ 45 °.

Further, as shown in FIG. 3, the root portions on both side surfaces in the width direction of each flange portion 21 are flange base portions so that stress does not concentrate on the root portions on both side surfaces in the width direction of each flange portion 21. A curved surface (including an arcuate surface) 21b that gradually becomes wider toward the outer peripheral surface of 20a is formed to be continuous with the outer peripheral surface of the flange base portion 20a.
As shown in FIG. 3, the front end surface of each flange portion 21 is formed as an arcuate surface 21 a having a radius that is approximately half the diameter of the brake rotor fitting portion 31 of the fitting shaft portion 30. That is, when the diameter dimension of the brake rotor fitting part 31 of the fitting shaft part 30 is φP and the radial dimension of the arcuate surface 21a at the tip of the flange part 21 is rQ, φP / 2≈rQ. Is formed.

As shown in FIGS. 2, 3, and 13, the fitting shaft portion 30 is configured to be disposed at a position between the adjacent flange portions 21.
That is, the fitting shaft portion 30 is formed with a fitting thick portion 400 for fitting the center hole of the wheel at the circumferential position excluding the axial region of the position where the flange portion 21 is formed. A flat portion 410 where the fitting thick portion 400 is not formed is formed at a circumferential position where the portion 21 is formed (a position where the flange portion 21 is formed). The fitting thick part 400 and the flat part 410 are alternately arranged and formed (staggered arrangement) in the circumferential direction of the fitting shaft part 30. Moreover, the fitting thick part 400 and the flat part 410 of this fitting shaft part 30 are formed at the same time as the flange part 21 is formed by the side extrusion process of cold forging.
Four flange portions 21 configured in the flanged shaft member 1 in the first embodiment are configured to extend radially in the outer diameter direction on the outer peripheral surface of the intermediate shaft portion 20. Further, the fitting thick part 400 formed in the circumferential position excluding the axial region of the position where the flange part 21 is formed, and the flat part 410 arranged and formed at a position between the adjacent flange parts 21. Four are formed.

In the wheel bearing device according to the first embodiment of the present invention configured as described above, the outer periphery of the flange base portion 20a positioned between the shaft portion 10 and the fitting shaft portion 30 by the side extrusion process of cold forging. By forming the plurality of flange portions 21 radially on the surface, it is possible to reduce the manufacturing cost while reducing the weight.
Further, as shown in FIG. 2, by forming the thick portion 23 on one side in the vicinity of the root portion of the flange portion 21, the strength in the vicinity of the root portion of the flange portion 21 can be improved satisfactorily. Excellent.

Further, the flange portion 21 of the wheel bearing device is a portion to which a wheel is attached, and a load from the wheel is repeatedly applied, and repeated stress is generated in the vicinity of the root portion of the flange portion 21. When the fitting shaft portion 30 is formed in the axial region of the position where the flange portion 21 is formed, repeated stress is applied to the flange portion 21 and the corner portion of the fitting shaft portion 30 (the root portion of the flange portion 21). May concentrate.
Therefore, the fitting shaft portion 30 is configured so as not to be formed in the axial region of the position where the flange portion 21 is formed (flat portion 410), so that the repeated stress accompanying the repeated load from the wheel causes the root of the flange portion 21. It is possible to prevent concentration in the department. In addition, the fitting shaft portion 30 is formed at a position between the adjacent flange portions by being formed at a circumferential position excluding an axial region at a position where the flange portion 21 is formed (fitting). Since it is the combined thickness part 400 (site | part in which the fitting part 31 for brake rotors and the fitting part 32 for wheels are formed)), the function in which the center hole of a wheel is fitted is not impaired.
Further, the flanged shaft member 1 receives a large compressive force at the time of cold forging forming, whereby the mechanical properties of the material after forming can be changed and surface hardening can be obtained, so that the strength can be improved. it can. Further, since the fitting shaft portion 30 is not formed in the axial direction region where the flange portion 21 is formed, the weight of this portion can be reduced, and there is no need for a turning process to delete the portion after molding. Thus, the manufacturing cost can be reduced.
Moreover, in the side extrusion process of cold forging, the fitting shaft part 30 is not formed in the axial direction region where the flange part 21 is formed. Therefore, the fluidity of the material in forming the flange portion 21 can be ensured, and the formability of the side extrusion process of cold forging can be ensured.

Next, a method for manufacturing the wheel bearing device according to the first embodiment will be described with reference to FIGS.
As shown in FIG. 4, a round bar of structural carbon steel (for example, carbon steel having a carbon content of about 0.5% such as S45C, S50C, S55C, etc.) is cut to a required length to obtain a shaft-shaped material 60. Form.
Next, the shaft-shaped material 60 is heated to around 800 ° C., for example, and then cooled and annealed.
Thereafter, the shaft-shaped material 60 is forward-extruded using a forging die device (not shown) for cold forging forward extrusion, whereby the shaft portion (large diameter portion 11, small diameter portion 12 and end shaft portion (this shaft portion) (In which the shaft end recess 16 is not formed) 15) 10, the intermediate shaft portion 20, and the fitting shaft portion 30 (in this state, the forged recess 33 and the fitting thick portion 400 (fitting for the brake rotor) The portion 31 and the portion where the wheel fitting portion 32 is formed) and the flat portion 410 are not formed), and the primary molded product 61 is manufactured by forward extrusion of cold forging.

  Next, as shown in FIG. 4 to FIG. 7, the shaft of the primary molded product 61 is formed while forming the forged recess 33 on the end surface of the central portion of the fitting shaft portion 30 by the forging die device 70 of the side extrusion process of cold forging. A plurality of flange portions 21 and flange base portions 20a are formed radially on the outer peripheral surface of the intermediate shaft portion 20 located between the portion 10 and the fitting shaft portion 30, and the secondary molded product 62 is manufactured.

As shown in FIGS. 5 to 7, in the forging die apparatus 70 for cold forging side extrusion, a primary molded product 61 is set between the first and second forming dies 71 and 72. A cavity 75 having a plurality of flange forming portions 78 for forming the plurality of flange portions 21 by lateral extrusion is formed.
The flange forming portion 78 is constituted by forming groove portions 76 and 77 formed in both the first and second forming dies 71 and 72, respectively.
That is, the facing distance between the guide surfaces 80 and 81 of the upper and lower wall surfaces of the molding grooves 76 and 77 of both the first and second molding dies 71 and 72 is set to a size equivalent to the plate thickness dimension of the flange portion 21. The facing interval between the guide surfaces (not shown) on both side wall surfaces is set to a size equivalent to the width dimension of the flange portion 21. And the cross-sectional shape of the flange forming part 78 is formed in the same shape as the cross-sectional shape of the flange part 21.

Further, in the molding groove portion 77 of the second molding die 72 on the opposite side to the thick wall portion 23 near the root portion of the flange portion 21, the back surface of the guide surface 81 except for the vicinity of the material inflow side is connected to the flange portion 21. An escape portion 84 that holds the gap S2 is formed therebetween.
On the other hand, in the first embodiment, the guide surface 80 of the molding groove portion 76 of the first molding die 71 that forms the thick portion 23 side near the base portion of the flange portion 21 is formed in a mold structure that does not have a relief portion. .

In the first embodiment, a thick portion forming groove portion 82 for forming the thick portion 23 of the flange portion 21 is formed on the material inflow side of the forming groove portion 76 of the first mold 71. The bottom surface of the thick-wall-forming groove 82 is formed on an inclined surface 82a that gradually decreases from the base portion side of the flange portion 21 toward the bolt hole 24 side (see FIGS. 1 and 2) and continues to the guide surface 80. (See FIG. 7).
In addition, the inclination angle θ2 of the inclined surface 82a of the bottom surface of the thick-wall forming groove 82 is the same as the inclination angle θ1 of the inclined surface 23a of the pressed portion 23 of the flange portion 21, that is, “20 ° ≦ θ2 ≦ 45 °”. It is desirable to set the relationship.
Moreover, the length dimension in the radial direction of the flange molding part 78 constituted by the molding groove parts 76 and 77 is set with a length dimension that does not contact the arc surface 21a at the tip of the flange part 21 (FIGS. 6 and 7). reference).

As shown in FIGS. 5 to 6, a forging die apparatus 70 for side extrusion of cold forging includes a punch 73. The punch 73 is positioned between the shaft portion 10 of the primary molded product 61 and the fitting shaft portion 30 while forming the forging recess 33 in the end surface of the center portion of the fitting shaft portion 30 by side extrusion of cold forging. A plurality of flange portions 21 and flange base portions 20a are formed radially on the outer peripheral surface of the intermediate shaft portion 20 and the fitting thick portion 400 (the brake rotor fitting portion 31 and the wheel rotor portion) of the fitting shaft portion 30 are formed. This is because the portion where the fitting portion 32 is formed (see FIGS. 3 and 13) and the flat portion 410 (see FIGS. 3 and 13) are formed together. The outer shape of the punch 73 configured in the cold forging die device 70 will be described in the case where the punch 73 is viewed in the axial section of the fitting shaft portion 30, and then the shape of the tip portion 74 will be described.
As shown in FIG. 10, in this Example 1, the punch 73 comprised in the forging die apparatus 70 of cold forging is comprised with the metal columnar member.
First, when viewed in the axial cross section of the fitting shaft portion 30, the cross-sectional area of the punch 73 is smaller than the cross-sectional area of the end surface of the fitting shaft portion 30 of the flanged shaft member 1. Further, in accordance with the number of flange forming portions 78 configured in the forging die device 70 (corresponding to the number of flange portions 21 of the flanged shaft member 1), the flange portions 21 are laterally extruded by the side extrusion process. A projecting portion 500 is formed to project. This is a flat portion 410 (see FIG. 3 and FIG. 13) formed in a circumferential position excluding the formation region of the flange portion 21, and a fitting thick portion disposed and formed at a position between adjacent flange portions. 400 (part where the brake rotor fitting portion 31 and the wheel fitting portion 32 are formed) (see FIGS. 3 and 13). The protruding portions 500 are formed to have the same width as the flange width of the flange portion 21, and are formed in the circumferential direction so as to protrude to the same outer diameter as the outer diameter of the fitting shaft portion 30.
Next, the tip portion 74 of the punch 73 is formed into a smooth chevron shape with a gradually reduced diameter, and the tip is formed with a smooth curved surface, in order to form the flange portion 21 radially and uniformly in the side extrusion process. Yes. This is also for forming a smooth recess shape so that stress does not concentrate and act on the forged recess 33 of the flanged shaft member 1.

First, as shown in FIG. 5, the primary molded product 61 is set in the first mold 71 of the first mold (lower mold) 71 and the second mold (upper mold) 72 of the forging die apparatus 70. Then, the second mold 72 is closed with respect to the first mold 71.
Thereafter, as shown in FIGS. 6 and 7, the punch 73 is lowered toward the center end face of the fitting shaft portion 30 of the primary molded product 61, and the center portion of the fitting shaft portion 30 is formed by the tip portion 74 of the punch 73. Both the first and second molding dies 71 and 72 are formed on the outer peripheral surface of the intermediate shaft portion 20 located between the shaft portion 10 of the primary molded product 61 and the fitting shaft portion 30 while forming the forged recess 33 on the end surface. A plurality of flange portions 21 are formed by laterally extruding the flange forming portion 78 of the cavity 75 formed in the above, and the thick portion 23 is formed on one side in the vicinity of the root portion of the flange portion 21. Moreover, the flange base part 20a is formed with this. In this way, a secondary molded product 62 is manufactured by side extrusion.
The intermediate shaft portion 20 forms part of the flange base portion 20a and the fitting shaft portion 30 by cold forging deformation.

Further, in the production of the secondary molded product, a plurality of flange portions 21 are formed, a flat portion 410 (see FIGS. 3 and 13) is formed on the flange portion 21, and at a position between adjacent flange portions. A fitting thick portion 400 (a portion where the brake rotor fitting portion 31 and the wheel fitting portion 32 are formed) (see FIGS. 3 and 13) is formed.
Further, in a state where the shaft-shaped material 60 is forward-extruded using a forging die device (not shown) for forward extrusion of cold forging, and the primary molded product 61 is manufactured, The forged recess 33, the fitting thick part 400 (the part where the brake rotor fitting part 31 and the wheel fitting part 32 are formed), and the flat part 410 are not formed.
As shown in FIG. 6, when the secondary molded product 62 is manufactured, a plurality of flange portions 21 are formed by side extrusion of cold forging, and the forged recesses of the fitting shaft portion 30 are formed. 33, the fitting thick part 400 (the part where the brake rotor fitting part 31 and the wheel fitting part 32 are formed), and the flat part 410 are formed.

Next, each part that requires turning of the secondary molded product 62 is turned. Then, by turning, for example, the bolt holes 24 are formed in each flange portion 21, and the first and second double-sided portions 25 and 26 are formed in the opening portions at both ends of the bolt hole 24. Further, a shaft end recess 16 is formed in the end shaft portion 15 of the shaft portion 10.
After that, after the secondary molded product 62 is quenched, the finished product is provided by turning or polishing the raceway surface 43 of the large-diameter portion 11 of the shaft portion 10, the rotor support surface 22 of the flange portion 21, and the like. The shaft member 1 is manufactured.

Moreover, in this Example 1, as shown in FIG. 2, in the 1st, 2nd double-sided taking parts 25 and 26 formed in the flange part 21 at the both-ends opening of the bolt hole 24, the thickness of the flange part 21 is thick. When the depth dimension of the first chamfered portion 25 located on the side of the portion 23 is T1, and the depth dimension of the second chamfered portion 26 on the opposite side is T2, the relationship is set so that “T1 <T2”. It is desirable that
That is, in a state after the serration shaft portion 29a (formed at the root portion of the shaft portion 29) 29a of the hub bolt 27 is press-fitted into the bolt hole 24 of the flange portion 21, the flange portion on the side where the depth dimension of the chamfered portion is large. Although 21 is a trace amount, it has a characteristic of warping deformation.
For this reason, even if “warping” occurs toward the thick wall portion 23 side of the flange portion 21 due to the side extrusion, the hub bolt 27 is press-fitted into the bolt hole 24 of the flange portion 21 as described above. “Warpage” of the flange portion 21 toward the thick portion 23 is reduced.

Moreover, in this Example 1, as shown in FIG. 2, it contacts the lower surface of the head 27 of the hub bolt 27 on one side surface (surface opposite to the rotor support surface 22) where the thick portion 23 of the flange portion 21 is formed. It is desirable that the bolt seat surface 21c be surface-finished by coining, thereby ensuring the necessary plane accuracy (for example, perpendicularity 0.1 or less) of the flange portion 21 and increasing the strength.
Further, the boundary R surface 23b of the inclined surface 23a of the thick portion 23 of the flange portion 21 or the range extending over the boundary R surface 23b and the inclined surface 23a (coining processing range W in FIG. 2) is exceeded. It is desirable to further increase the strength of the flange portion 21 by finishing the surface by coining.
Further, it is desirable that the surface hardness by coining is finished to HRC25 or more and the surface roughness to Ra6.3 or less.

Finally, as shown in FIG. 1, a plurality of balls 50, 51, cages 52, 53, and an outer ring member 45 are assembled on the outer peripheral surface of the shaft portion 10 of the shaft member 1 with flange.
Then, after the inner ring body 42 is fitted on the outer peripheral surface of the small-diameter portion 12 of the shaft portion 10, the distal end portion of the end shaft portion 15 is caulked radially outward to form the caulking portion 17, thereby forming the small-diameter portion 12. The inner ring body 42 is fixed to the outer peripheral surface of the inner ring.
In addition, before or after the angular ball bearing 41 is assembled to the outer peripheral surface of the shaft portion 10 of the flanged shaft member 1, the shaft portion 29 of the hub bolt 27 extends from the first chamfered portion 25 side of the bolt hole 24 of the flange portion 21. The hub bolt 27 is fixed to the flange portion 21 by being inserted and the serration shaft portion 29 a of the shaft portion 29 is press-fitted into the bolt hole 24.
With this, the wheel bearing device is manufactured.

  As shown in FIG. 1, a pulsar ring 96 having a detected portion 95 corresponding to the speed sensor 90 in the circumferential direction is press-fitted and fixed to the outer peripheral surface of the inner ring body 42 as necessary. In this case, a covered cylindrical cover member 91 is press-fitted and fixed to the inner peripheral surface of the end portion of the outer ring member 45, and the speed sensor 90 is attached to the cover plate portion 92 of the cover member 91 so that the detection portion thereof is covered by the pulsar ring 96. It is attached facing the detector 95.

  In the method of manufacturing the wheel bearing device according to the first embodiment of the present invention configured as described above, the flange portion 21 and the second portion are disposed on the portion corresponding to the side opposite to the thick portion 23 side near the root portion of the flange portion 21. A relief portion 84 that holds the gap S <b> 2 is formed between the molding groove portion 77 of the two molding die 72. For this reason, the material and the second molding die 72 during the cold forging material flow when the flange portion 21 is formed while the forging recess 33 is formed on the end surface of the center portion of the fitting shaft portion 30 by the tip portion 74 of the punch 73. The contact frictional force with the molding groove 77 can be reduced by an amount corresponding to the relief portion 84. Accordingly, it is possible to reduce the wear of the mold, particularly the second mold 72, and to improve the mold life.

Moreover, in this Example 1, the 1st shaping | molding die 71 is made into the type | mold structure in which the shaping | molding groove part 76 does not have an escape part, Therefore The thick part of the flange part 21 by the material fluidity along the fiber flow of cold forging It is possible to satisfactorily suppress the occurrence of “warping” toward the 23 side.
That is, in cold forging, there is a characteristic that the flange portion 21 is likely to be warped toward the thick wall portion 23 due to the material fluidity along the fiber flow. Due to the warpage of the flange portion 21 toward the thick portion 23 side, for example, it may be difficult to finish the entire rotor support surface 22 of the flange portion 21 to a flat surface. In the case where the entire surface of the rotor support surface 22 of the flange portion 21 is not finished to a flat surface, for example, it is assumed that the mounting of the brake rotor 55 becomes unstable. However, as described above, it is easy to finish the entire surface of the rotor support surface 22 of the flange portion 21 to a flat surface by suppressing the occurrence of “warping” toward the thick wall portion 23 side of the flange portion 21. It becomes possible to attach the rotor 55 stably.

  Further, the punch 73 provided in the forging die device 70 for cold forging corresponds to the number of the flange portions 21 at a position corresponding to the formation region of the flange portion 21 when viewed in the axial section of the fitting shaft portion 30. A protruding portion 500 is formed to protrude in the side extrusion direction of the flange portion 21. The protruding portion 500 is formed to have the same width as the flange width of the flange portion 21, and protrudes to the same outer diameter as the outer diameter of the fitting shaft portion 30. By using this punch 73, the fitting shaft portion 30 is formed at the circumferential position excluding the formation region of the flange portion 21 at the same time when the flange portion 21 is formed, and the fitting shaft portion is formed between the adjacent flange portions. 30 can be arranged and formed. Since the formation of the flange portion 21 and the formation of the fitting shaft portion 30 are performed in the same process, the manufacturing cost can be reduced. Moreover, since the fitting shaft part 30 is not formed in the axial direction area | region of the position in which the flange part 21 is formed, the weight reduction of this site | part can be aimed at. Further, there is no need for a turning process for deleting the portion after molding, and the manufacturing cost can be reduced.

Next, a method for manufacturing a wheel bearing device according to Embodiment 2 of the present invention will be described with reference to FIG.
As shown in FIG. 8, in the second embodiment, the material inflow side of both guide surfaces 80 and 81 of the molding grooves 76 and 77 of the first and second molding dies 71 and 72 constituting the flange molding portion 78. Relief portions 83 and 84 that hold gaps S1 and S2 between the flange portion 21 and the flange portion 21 are formed on the back side excluding the vicinity.
8, the clearance dimension between the bottom surface of the molding groove 76 forming the clearance S1 of the relief portion 83 of the first mold 71 and one side surface of the flange portion 21 is A, and the relief portion of the second mold 72 is provided. The flange portion is set to a relationship of “0.5 mm> A ≦ B <0.5 mm” where B is a clearance dimension between the bottom surface of the molding groove portion 77 forming the clearance S2 of 84 and the other side surface of the flange portion 21. It is desirable to suppress the occurrence of warpage toward the thick portion 23 side of 21.

Further, in the second embodiment, the outer diameter dimension φC of the guide surface 80 of the first molding die 71 located on the thick portion 23 side near the base portion of the flange portion 21 is used, and the guide of the second molding die 72 on the opposite side is provided. When the outer diameter dimension φD of the surface 81 is set, the relationship “φC> φD” is set.
Since other configurations of the second embodiment are formed in the same manner as the first embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted.

Therefore, in the second embodiment, by forming the secondary molded product 62 using both the first and second molding dies 71 and 72 described above, the material and the cavity 75 at the time of cold forging material flow can be obtained. The contact friction force with the flange forming portion 78 can be further reduced, and the effect of improving the mold life of both the first and second forming dies 71 and 72 is great.
Further, the outer diameter dimension φC of the guide surface 80 of the first molding die 71 located on the thick wall portion 23 side near the root portion of the flange portion 21 is set, and the outer diameter dimension of the guide surface 81 of the second molding die 72 on the opposite side. By setting so that the relationship of “φC> φD” is established when φD, the occurrence of “warping” toward the thick portion 23 side of the flange portion 21 due to the material fluidity of cold forging is suppressed. Can do.

Next, a method for manufacturing a wheel bearing device according to Embodiment 3 of the present invention will be described with reference to FIG.
As shown in FIG. 9, in the third embodiment, the material inflow side of both guide surfaces 80, 81 of the molding grooves 76, 77 of the first and second molding dies 71, 72 constituting the flange molding part 78. Relief portions 183 and 184 that hold gaps S3 and S4 are formed between the flange portion 21 and the rear side except the vicinity.
Both relief portions 183 and 184 are formed in a taper shape in which the material inflow side of the flange forming portion 78 is wide and gradually narrows toward the far outer side in the radial direction, and the tip portions form parallel surfaces.

Further, as shown in FIG. 9, the maximum gap dimension between the bottom surface of the molding groove 76 forming the gap S3 of the relief part 183 of the first mold 71 and one side surface of the flange portion 21 is E, and the minimum gap dimension is F. When the maximum clearance dimension between the bottom surface of the molding groove 77 forming the clearance S4 of the escape portion 184 of the second molding die 72 and the other side surface of the flange portion 21 is G and the minimum clearance dimension is H, “E> It is desirable to set the relationship of “F”, “G> H”, “F ≧ 0.0 mm”, “H ≧ 0.0 mm” to suppress the occurrence of warping of the flange portion 21.
Furthermore, the occurrence of “warping” toward the thick wall side of the flange portion 21 by setting the relationship of “1.0 mm> E ≦ G <1.0 mm” and “0.3 mm> F ≦ H <0.3 mm”. It is more desirable to suppress this.
Since other configurations of the third embodiment are formed in the same manner as the first embodiment, the same components are denoted by the same reference numerals, and the description thereof is omitted.

  Therefore, in the third embodiment, by forming the secondary molded product 62 by using both the first and second molding dies 71 and 72 described above, the material and the flange molding portion at the time of the material flow of the cold forging. In addition to the effect of improving the mold life of the mold by reducing the contact friction force between the flange portion 78 and the flange portion 21, the occurrence of “warping” toward the thick portion 23 side can be suppressed.

Next, a method for manufacturing a wheel bearing device according to Embodiment 4 of the present invention will be described with reference to FIGS.
As shown in FIGS. 11 and 12, in the fourth embodiment, the configuration of the protrusion 500 provided on the punch included in the forging die device 70 for cold forging is changed to that formed on the punch 73. The second forging die (upper die) 72 included in the forging die device 70 for cold forging is formed.
First, the forging die device (not shown) for forward forging for cold forging is used to forwardly extrude the shaft-shaped material 60, whereby the shaft portion (large diameter portion 11, small diameter portion 12, and end shaft portion (this shaft portion) (In which the shaft end recess 16 is not formed) 15) 10, the intermediate shaft portion 20, and the fitting shaft portion 30 (in this state, the forged recess 33 and the fitting thick portion 400 (fitting for the brake rotor) The portion 31 and the portion where the wheel fitting portion 32 is formed) and the flat portion 410 are not formed.) 30 is formed, and the primary molded product 61 is manufactured by forward extrusion of cold forging.

In the primary molded product according to the fourth embodiment, a notch 500b is formed at a circumferential position excluding an axial region at a position where the flange portion 21 is formed. That is, the fitting shaft part 30 fitting thick part 400 (part where the brake rotor fitting part 31 and the wheel fitting part 32 are formed) is arranged and configured at a position between the adjacent flange parts 21. In this way, a notch (flat portion 410) is formed in advance from the primary molded product. In the state of processing of the primary molded product 61, the fitting shaft portion 30 is formed with a forged recess portion 33 and a fitting thick portion 400 (a brake rotor fitting portion 31 and a wheel fitting portion 32). The flat portion 410 is not formed.
The second molding die (upper die) 72 has a fitting shaft corresponding to the number of flange portions 21 at a position corresponding to the formation region of the flange portion 21 when viewed in the axial cross section of the fitting shaft portion 30. A protruding portion 500a protruding in the center direction of the portion 30 is formed. The protruding portion 500a is formed with the same width as the flange width of the flange portion 21, and protrudes to the same inner diameter as the inner diameter of the fitting shaft portion 30. Is formed. The protrusion 500a of the second mold (upper mold) 72 and the notch 500b of the primary molded product 61 are configured to fit. Further, the protrusions 500 are not formed on the punch 73 provided in the cold forging forging die apparatus 70 of the fourth embodiment.

Next, as shown in FIGS. 11 to 12, the shaft of the primary molded product 61 is formed while forming the forged recess 33 on the end face of the center portion of the fitting shaft portion 30 by the forging die device 70 for cold forging side extrusion. A plurality of flange portions 21 and flange base portions 20a are formed radially on the outer peripheral surface of the intermediate shaft portion 20 located between the portion 10 and the fitting shaft portion 30, and the fitting thick portion of the fitting shaft portion 30 400 (part where the brake rotor fitting portion 31 and the wheel fitting portion 32 are formed) (see FIGS. 3 and 13) and the flat portion 410 (see FIGS. 3 and 13) are formed together. Then, the secondary molded product 62 is manufactured.
As described above, the flat portion 410 is formed at the circumferential position excluding the formation region of the flange portion 21 at the same time when the flange portion 21 is formed by using the protruding portion 500a formed in the second mold (upper die) 72. (See FIG. 3 and FIG. 13), and a fitting thick portion 400 (a brake rotor fitting portion 31 and a wheel fitting portion 32 is formed at a position between adjacent flange portions. (Refer to FIG. 3 and FIG. 13).
Since other configurations of the fourth embodiment are formed in the same manner as the first embodiment, the same components are denoted by the same reference numerals, and the description thereof is omitted.

  Therefore, in the fourth embodiment, the forging die device for cold forging is changed from the configuration of the protrusion 500 provided in the punch provided in the forging die device 70 for cold forging to the punch 73 formed therein. This can also be achieved in the configuration formed in the second molding die (upper die) 72 included in 70.

  In addition, this invention is not limited to the said Examples 1-4, In the range which does not deviate from the summary of this invention, it can also be implemented with a various form.

DESCRIPTION OF SYMBOLS 1 Shaft member with a flange 10 Shaft part 11 Large diameter part 12 Small diameter part 15 End shaft part 16 Shaft end recessed part 17 Caulking part 20 Intermediate shaft part 20a Flange base 21 Flange part 21a Arc surface 21b Curved surface 21c Bolt seat surface 22 Rotor support surface 23 thick part 23a outer inclined surface 23b boundary R surface 23c annular flat surface 24 bolt hole 25 first chamfer 26 second chamfer 27 hub bolt 28 head 29 shaft 29a serration shaft 30 fitting shaft 31 brake rotor Fitting part 32 wheel fitting part 33 forged recess 41 angular contact ball bearing (rolling bearing)
42 Inner ring body 43 Raceway surface 44 Raceway surface 45 Outer ring member 46 Raceway surface 47 Raceway surface 48 Car body side flange 50 Ball 51 Ball 52 Cage 53 Cage 55 Brake rotor 60 Shaft material 61 Primary molded product 62 Secondary molded product 70 Forging Mold device 71 First molding die 72 Second molding die 73 Punch 74 Tip portion 75 Cavity 76 Molding groove portion 77 Molding groove portion 78 Flange molding portion 80 Guide surface 81 Guide surface 82 Compaction portion molding groove portion 82a Inclined surface 83 Relief portion 84 Relief Part 90 speed sensor 91 cover member 92 lid plate part 95 detected part 96 pulsar ring 400 fitting thick part 410 flat part 500 projecting part 500a projecting part 500b notch part

Claims (2)

  A shaft portion to which the rolling bearing is assembled, a fitting shaft portion formed on one end side of the shaft portion and into which a center hole of a wheel is fitted, and an outer portion positioned between the shaft portion and the fitting shaft portion. A method of manufacturing a wheel bearing device including a flanged shaft member having a plurality of flange portions extending radially in a radial direction and through which a bolt hole in which a hub bolt for tightening the wheel is disposed is provided. ,
  A forging die device for cold forging equipped with a punch forms a forged recess on the end surface of the center portion of the fitting shaft portion, radially on the outer peripheral surface between the shaft portion and the fitting shaft portion in the radial direction. A flange portion forming step of forming the flange portion by extending side extrusion;
  A fitting shaft portion forming step of arranging and forming the fitting shaft portion between adjacent flanges by forming the fitting shaft portion at a circumferential position excluding an axial region where the flange portion is formed. And performing both the flange portion forming step and the fitting shaft portion forming step as the same step,
  The punch included in the forging die device for cold forging is the flange portion corresponding to the number of the flange portions at a position corresponding to the formation region of the flange portion when viewed in the axial section of the fitting shaft portion. A protruding part protruding in the side extrusion direction is formed,
  The protruding portion is formed with the same width as the flange width of the flange portion, and is formed to protrude to the same outer diameter as the outer diameter of the fitting shaft portion,
  Using the punch, at the same time as forming the flange portion, a fitting shaft portion is formed at a circumferential position excluding a formation region of the flange portion, and the fitting shaft portion is disposed and formed between adjacent flanges. A method for manufacturing a wheel bearing device.   It is a manufacturing method of the bearing device for wheels according to claim 1,
  The structure of the protrusion provided on the punch included in the cold forging die device is formed on the forming die included in the cold forging die device, instead of being formed on the punch. ,
  The molding die protrudes in the center direction of the fitting shaft portion corresponding to the number of the flange portions at a position corresponding to the formation region of the flange portion when viewed in the axial section of the fitting shaft portion. A protrusion is formed,
  The projecting portion is formed to have the same width as the flange width of the flange portion, and is formed to project to the same inner diameter as the inner diameter of the fitting shaft portion,
  Using the molding die, at the same time as forming the flange portion, a fitting shaft portion is formed at a circumferential position excluding the formation region of the flange portion, and the fitting shaft portion is disposed and formed between adjacent flanges. A method for manufacturing a wheel bearing device.

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