JP2010188828A - Method of manufacturing wheel bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a wheel bearing device allowing reduction of manufacturing cost, while reducing weight. <P>SOLUTION: This wheel bearing device includes a flanged shaft member 1 having a shaft portion 10 to which a rolling bearing 41 is assembled, a fitting shaft portion 30 fitted with a center hole of a wheel, and a plurality of flange portions 21 extended radially in the outer diameter direction on an outer peripheral surface located between the shaft portion 10 and the fitting shaft portion 30 and penetrated with bolt holes 24 of hub bolts 27. When manufacturing the wheel bearing device, the bolt holes 24 are formed in the flange portions 21 after forming the flange portions 21 on the outer peripheral surface of an intermediate shaft portion 20 between the shaft portion 10 and the fitting shaft portion 30, while forming a forged recess 33 at an end face of a center portion of the fitting shaft portion 30 by side extrusion of cold forging. Subsequently, a bolt seat surface 21c around an opening edge on one side of each of bolt holes 24 of the flange portions 21 is finished into a flat surface by coining. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

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 producing a forged product by cold forging, it is necessary to form a plurality of flange portions made of cut and raised pieces at one shaft end portion of the forged product. Cost increases.

  In view of the above problems, an object of the present invention is to provide a method for manufacturing a wheel bearing device capable of reducing the manufacturing cost while reducing the weight.

In order to solve the above-mentioned problems, a manufacturing method for a wheel bearing device according to claim 1 of the present invention includes a shaft portion on which a rolling bearing is assembled, and a wheel center hole fitted on one end side of the shaft portion. A fitting shaft portion to be inserted, and a bolt hole extending radially outwardly on the outer peripheral surface located between the shaft portion and the fitting shaft portion and in which a hub bolt for tightening the wheel is disposed. A wheel bearing device including a flanged shaft member having a plurality of flange portions,
After forming the flange portion on the outer peripheral surface between the shaft portion and the fitting shaft portion while forming a forged recess in the center end surface of the fitting shaft portion by side extrusion of cold forging, Form bolt holes in the flange,
Then, the bolt seat surface around one side opening edge of the bolt hole of the flange portion is finished into a flat surface by coining.

According to the above configuration, the plurality of flange portions are radially formed on the outer peripheral surface located between the shaft portion and the fitting shaft portion by the side extrusion process of cold forging, thereby reducing the manufacturing cost while reducing the weight. Can be reduced.
In particular, after the bolt hole is formed in the flange, it is necessary to turn the bolt seat surface of the flange portion by finishing the bolt seat surface around one side opening edge of the bolt hole of the flange portion into a flat surface by coining. Disappears.
Further, by finishing the bolt seat surface of the flange portion to a flat surface by coining, the strength of the flange portion can be improved more favorably than when turning.

A method for manufacturing a wheel bearing device according to claim 2 is a method for manufacturing a wheel bearing device according to claim 2,
When forming a plurality of flange portions radially by side extrusion of cold forging, forming a thick portion on one side of the flange portion,
When coining a bolt seat surface around one side opening edge of the bolt hole of the flange portion, finishing is performed by coining from the tip of one side surface of the flange portion including the bolt seat surface to the boundary R surface of the thick portion. It is characterized by doing.

According to the said structure, when forming a some flange part radially by the side extrusion process of cold forging, the strength of a flange part is improved much more by forming a thick part in one side of a flange part. be able to.
Further, in the side extrusion process of cold forging, warpage toward the thick part may occur in the flange part due to the material fluidity along the fiber flow.
If warpage toward the thick wall portion occurs in the flange portion, when coining the bolt seat surface around the one side opening edge of the bolt hole of the flange portion, the above-described warpage of the flange portion is coined. Can be corrected by.
Furthermore, by finishing from the tip of one side of the flange part including the bolt seat surface to the boundary R surface of the thick part by coining, the strength of the flange part is increased, and the effect of correcting the warp of the flange part is great. .

The method for manufacturing a wheel bearing device according to claim 3 is the method for manufacturing the wheel bearing device according to claim 1 or 2,
A bolt seat surface around one side opening edge of the bolt hole of the flange portion is finished by coining, and a chamfered portion is formed on the one side opening edge of the bolt hole.

  According to the above configuration, the bolt seat surface around the one side opening edge of the bolt hole of the flange portion is finished by coining, and the one side of the bolt hole is formed by forming the chamfered portion on the one side opening edge of the bolt hole. The trouble of turning the chamfered portion at the opening edge can be saved.

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.

  A mode for carrying out the present invention will be described in accordance with an embodiment.

First, a wheel bearing device according to a first embodiment of the present invention will be described with reference to FIGS.
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, the fitting shaft portion 30 is formed with a brake rotor fitting portion 31 on the flange portion 21 side, and a wheel fitting portion 32 having a slightly smaller diameter than the brake rotor fitting portion 31 on the distal end side. ing.

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) (on the side that forms the vehicle inner surface when the rotor support surface 22 of the flange portion 21 is the vehicle outer 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 axis S of the flanged shaft member 1) θ1 is the material flow during cold forging and demolding after forming. Is preferably set to a relationship of “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 a circular arc surface) 21b that gradually becomes wider toward the outer peripheral surface of 20a is formed, and the curved surface 21b of each adjacent flange portion 21 is 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.

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, after heating the shaft-shaped raw material 60 to around 800 ° C., for example, it is 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) 10), an intermediate shaft portion (forming a part of the flange base portion 20a and the fitting shaft portion 30) 20, and a fitting shaft portion (in this state) The forging recess 33 and the brake rotor fitting portion 31 are not formed, and a 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 a forged recess 33 on the end face of the central portion of the fitting shaft portion 30 by a forging die device 70 for side extrusion of cold forging. A plurality of flange portions 21 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 to produce a secondary molded product 62.

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 in the vicinity of the base portion of the flange portion 21, the back side of the guide surface 81 excluding 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, and continues to the guide surface 80 (see FIG. 7). .
Further, the inclination angle θ2 of the inclined surface 82a of the bottom surface of the thick part forming groove 82 is the same as the inclination angle θ1 of the inclined surface 23a of the thick part 23 of the flange portion 21, that is, “20 ° ≦ θ2 ≦ 45 °”. Is set to 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).

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 to a flange forming portion 78 of the cavity 75 formed in the side wall, and a thick portion 23 is formed on one side in the vicinity of the root portion of the flange portion 21. A secondary molded product 62 is manufactured by the side extrusion process. The intermediate shaft portion 20 forms part of the flange base portion 20a and the fitting shaft portion 30 by cold forging deformation.

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.
In addition, as shown in FIG. 2, the first and second double-sided chamfers 25, 26 formed in the flange portion 21 at the openings at both ends of the bolt hole 24 are positioned on the thick portion 23 side of the flange portion 21. It is desirable to set the relationship of “T1 <T2” when the depth dimension of the first chamfered portion 25 is T1 and the depth dimension of the second chamfered portion 26 on the opposite side is T2.
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 portion 23 side of the flange portion 21 by 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.

As shown in FIG. 2, the bolt seat surface 21 c that is in contact with 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 is formed by coining. Surface finished.
It is desirable that the surface hardness by coining is finished to HRC25 or more and the surface roughness to Ra6.3 or less.
Further, the range from the tip of one side surface of the flange portion 21 including the bolt seat surface 21c to the boundary R surface 23b of the inclined surface 23a of the thick portion 23 of the flange portion 21 or the boundary R surface 23b and the inclined surface 23a (in FIG. It is desirable to finish the surface by coining over the coining range W).

  After that, after the secondary molded product 62 is quenched, 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 are turned or polished to provide a finished product. The shaft member 1 is manufactured.

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 for manufacturing a wheel bearing device according to the first embodiment of the present invention configured as described above, the flange 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 outer peripheral surface of the base portion (intermediate shaft portion 20) 20a, the manufacturing cost can be reduced while reducing the weight.
In particular, after forming the flange portion 21 by side extrusion of cold forging and forming the bolt hole 24 in the flange portion 21, the bolt seat surface 21 c around the one side opening edge of the bolt hole 24 of the flange portion 21 is formed. By finishing the flat surface by coining, it is not necessary to turn the bolt seat surface 21c of the flange portion 21.
Furthermore, by finishing the bolt seat surface 21c of the flange portion 21 to a flat surface by coining, the strength of the flange portion 21 can be improved more favorably than when turning.

Moreover, in this Example 1, when forming the some flange part 21 radially by the side extrusion process of cold forging, the flange part 21 is formed by forming the thick part 23 in one side surface of the flange part 21. The strength of can be further improved.
Further, in the side extrusion process of cold forging, warpage toward the thick portion 23 may occur in the flange portion 21 due to the material fluidity along the fiber flow.
If warpage toward the thick portion 23 occurs in the flange portion 21, when the bolt seating surface 21 c of the bolt hole 24 of the flange portion 21 is subsequently coined, the above-described warpage of the flange portion 21 is coined. It can be corrected by processing.

Further, a range extending from the tip of one side surface of the flange portion 21 including the bolt seat surface 21c to the boundary R surface 23b of the inclined surface 23a of the thick portion 23 or the boundary R surface 23b and the inclined surface 23a (coining processing range W in FIG. 2). ), The strength of the flange portion 21 is increased, and the effect of correcting the warp of the flange portion 21 is great.
That is, due to the warp toward the thick portion 23 side of the flange portion 21, for example, it may be difficult to finish the entire surface of the 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 correcting the “sleigh” toward the thick portion 23 side of the flange portion 21 by coining. It becomes possible to attach the brake rotor 55 stably.

Further, in the first embodiment, a gap S <b> 2 is maintained between the flange portion 21 and the molding groove portion 77 of the second molding die 72 in a portion corresponding to the opposite side of the thick portion 23 side near the root portion of the flange portion 21. An escape portion 84 is formed. 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.

In addition, this invention is not limited to the said Example 1, In the range which does not deviate from the summary of this invention, it can also be implemented with a various form.
For example, in the first embodiment, the gap S <b> 2 is maintained between the molding groove 77 of the second molding die 72 of the forging die device 70 and the thick portion 23 side and the opposite side portion near the root portion of the flange portion 21. Although the case where the relief portion 84 is formed is illustrated, the present invention can be implemented as a mold structure without the relief portion 84.

DESCRIPTION OF SYMBOLS 1 Shaft member with a flange 10 Shaft part 20 Intermediate shaft part 20a Flange base part 21 Flange part 21c Bolt seat surface 22 Rotor support surface 23 Thick part 24 Bolt hole 25 1st chamfer part 26 2nd chamfer part 27 Hub bolt 30 Fitting shaft part 33 Forged recess 41 Angular contact ball bearing (rolling bearing)
45 Outer ring member 70 Forging die device 71 First molding die 72 Second molding die 73 Punch 75 Cavity 78 Flange molding part

Claims (3)

A shaft portion to which the 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 an outer peripheral surface located between the shaft portion and the fitting shaft portion A wheel bearing device including a flanged shaft member that has a plurality of flange portions that are radially extended in an outer diameter direction and in which a bolt hole in which a hub bolt for tightening the wheel is disposed is provided,
After forming the flange portion on the outer peripheral surface between the shaft portion and the fitting shaft portion while forming a forged recess in the center end surface of the fitting shaft portion by side extrusion of cold forging, Form bolt holes in the flange,
Then, the bolt bearing surface around the one side opening edge of the bolt hole of the flange portion is finished into a flat surface by coining, and the method for manufacturing the wheel bearing device is characterized. It is a manufacturing method of the bearing device for wheels according to claim 2,
When forming a plurality of flange portions radially by side extrusion of cold forging, forming a thick portion on one side of the flange portion,
When coining a bolt seat surface around one side opening edge of the bolt hole of the flange portion, finishing is performed by coining from the tip of one side surface of the flange portion including the bolt seat surface to the boundary R surface of the thick portion. A method for manufacturing a wheel bearing device. It is a manufacturing method of the bearing device for wheels according to claim 1 or 2,
A method of manufacturing a wheel bearing device, comprising: finishing a bolt seat surface around one side opening edge of a bolt hole of a flange portion by coining, and forming a chamfered portion on one side opening edge of the bolt hole.

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