JP2001294010A - Bearing unit for wheel drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve yield and to form a structure with excellent durability. SOLUTION: An inside diameter side male spline part 17a is formed on an outer peripheral face close to an inner end of a hub 4a by plastic working such as rolling working and press working. On a part of outer peripheral face of the hub 4a, an outer end of a clearance groove 28a formed in a state adjoining an axial outside of the inside diameter side male spline part 17a is positioned axially outside an inner end of a cylindrical face part 29 formed on a middle part inner peripheral face of an inner ring 9. An inner end of the inside diameter side male spline part 17a is positioned axially outside an inner end face of an auxiliary ring 14 in a state assembling the inner ring 9 and the auxiliary ring 14 to the hub 4a at a predetermined position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel drive bearing unit in which a constant velocity joint and a hub unit are integrated, and a drive wheel #FF vehicle (front engine front wheel) supported by an independent suspension type suspension. Driving car) front wheel, F
The rear wheels of the R vehicle (front-engine rear-wheel drive vehicle) and the RR vehicle (rear-engine rear-wheel drive vehicle) and all the wheels の of the 4WD vehicle (four-wheel drive vehicle) are rotatably supported by the suspension system. In addition, it is used to rotationally drive the drive wheels.

[0002]

2. Description of the Related Art In order to rotatably support wheels with respect to a suspension device, various bearing units are used in which an outer ring and an inner ring are rotatably combined via rolling elements. or,
In addition to supporting the drive wheels on an independent suspension,
The wheel drive bearing unit for rotating this drive wheel, in combination with a constant velocity joint, controls the rotation of the drive shaft regardless of the relative displacement between the differential gear and the drive wheel and the steering angle given to the wheel. It must be transmitted smoothly (with constant velocity) to the wheels. Conventionally, as a wheel drive bearing unit that can be configured to be relatively small and lightweight in combination with such a constant velocity joint, Japanese Patent Application Laid-Open No. H10-264605 and US Pat.
What is described in the specification etc. is known.

[0003] FIG.
FIG. 1 shows an example of a conventionally known wheel drive bearing unit having a structure similar to that described in U.S. Pat. An outer ring 1 that is not rotated while supported by a suspension device in an assembled state to a vehicle has a first mounting flange 2 for supporting the suspension device on an outer peripheral surface, and a double-row outer ring raceway 3, 3 on an inner peripheral surface. On the surface,
Have each. A hollow cylindrical hub 4 is supported inside the outer race 1 concentrically with the outer race 1. This hub 4
Is a second mounting flange for supporting the wheel near the end of the outer peripheral surface (in the axial direction, the outer side in the width direction in an assembled state to an automobile. The same throughout the specification; the left side of each drawing). 5, a first inner raceway 6 is also formed at the center. Also, in the outer peripheral surface of the hub 4 (in the axial direction, the center side in the width direction in an assembled state to the automobile).
Same throughout this specification. Right side of each figure. A small-diameter stepped portion 7 is formed near the end, and an inner ring 9 having a second inner raceway 8 formed on the outer peripheral surface of the small-diameter stepped portion 7 is externally fixed.
A plurality of rolling elements 10, 10 are provided between the outer raceways 3, 3 and the first and second inner raceways 6, 8, respectively, so as to freely roll, and are provided inside the outer race 1. The hub 4 is rotatably supported. Seal rings 11 and 11 are provided between inner peripheral surfaces of both ends of the outer ring 1 and outer peripheral surfaces of an intermediate portion of the hub 4 and an inner end of the inner ring 9.
Are provided to close the openings at both ends of the space where the rolling elements 10 and 10 are installed.

[0004] A housing 13 serving as an outer ring of a Zeppa type constant velocity joint 12 is connected to an inner end of the hub 4 via an auxiliary ring 14 which is a connecting member.
Of the inner and outer peripheral surfaces of the auxiliary ring 14 formed in a short cylindrical shape, an inner peripheral female spline portion 15 is formed on the inner peripheral surface, and an outer male spline portion 16 is formed on the outer peripheral surface. . With such an auxiliary ring 14, the inner diameter side male spline portion 17 and the inner diameter side female spline portion 15 formed on the inner end portion outer peripheral surface of the hub 4 are spline-engaged without play. In, it is assembled. And
In this state, the swaged portion 1 formed at the inner end of the hub 4
8, the inner end face of the auxiliary ring 14 is pressed down, and the auxiliary ring 14 is fixed to the inner end of the hub 4 without play. The caulking portion 18 is formed by plastically deforming the inner end of the hub 4 outward in the diameter direction. The inner diameter side male spline portion 17 is formed by a cutting process using a hob, and is formed at a portion adjacent to the inner diameter side male spline portion 17 on the outer side in the axial direction on the outer peripheral portion near the inner end of the hub 4. An escape groove 28 is formed for releasing chips generated by the cutting process.

On the other hand, an outer diameter side female spline portion 20 formed on an outer end portion inner circumference surface of the housing portion 13 is splined to the outer diameter side male spline portion 16 formed on the outer peripheral surface of the auxiliary ring 14. Have been combined. A plurality of engagement grooves 22 are formed on the inner peripheral surface of the inner half portion of the housing portion 13 so as to be orbits of the balls 21, 21, each of which forms a Zeppa type constant velocity joint 12. On the other hand, the outer diameter side female spline portion 20 is formed on the inner peripheral surface of the outer end portion. And, as described above, the outer diameter side female spline portion 20 and the outer diameter side male spline portion 16 formed on the outer peripheral surface of the auxiliary ring 14 are spline-engaged.

[0006] As described above, the splines are engaged with each other.
A retaining ring 23 is provided between the outer diameter side female spline portion 20 and the outer diameter side male spline portion 16 so that the housing portion 13 and the auxiliary ring 14 are not separated. That is, the annular ring-shaped retaining ring 23 is formed on the inner peripheral surface of the auxiliary ring 14 over the entire circumference and the inner locking groove 24 formed on the outer peripheral surface of the housing portion 13 over the entire circumference. So that the housing portion 13 and the auxiliary ring 14 do not move in the axial direction. Also, the housing portion 13
On the inner peripheral surface of the intermediate part, a cap 26 formed by pressing a steel plate is fitted and fixed, so that the space between the plurality of balls 21 and 21 and the internal space of the hub 4 communicating with the outside are formed. It is shut off.

When assembling the above-configured wheel drive bearing unit to an automobile, the first mounting flange 2 is required.
, The outer ring 1 is supported by the suspension device, and the wheel is fixed to the hub 4 by the second mounting flange 5. An outer end of a drive shaft (not shown), which is rotationally driven by an engine via a transmission, is connected to the housing portion 13.
Is spline-engaged inside the inner ring 27 for the constant velocity joint supported inside. When the automobile is running, the rotation of the inner ring 27 for the constant velocity joint is performed by the plurality of balls 21,
The power is transmitted to the hub 4 via the housing 21 and the housing portion 13, and the wheels fixed to the hub 4 are rotationally driven.

[Problems to be solved by the invention]

In order to fix the auxiliary ring 14 to the inner end of the hub 4, the inner end of the hub 4 is swaged diametrically outward to form a swaged portion 18. The ends are plastically deformed while being subjected to a tensile stress in the circumferential direction. The inner end of the hub 4 is plastically deformed to prevent the caulking portion 18 from being damaged such as a crack,
In order to ensure sufficient durability, the caulking portion 1
It is necessary to alleviate the concentration of stress applied to the inner end of the hub 4 during the forming operation of the hub 8.

On the other hand, in the case of the above-described conventional structure, as shown in FIG.
Before forming the inner ring 9 (FIGS. 6 and 8),
The auxiliary ring 14 is spline-engaged with the inner diameter side male spline portion 17, and the outer end surface of the auxiliary ring 14 and the inner end surface of the inner ring 9 abut against each other. Male spline part 1
The inner end (point P in FIG. 7) is located axially inward of the inner end surface of the auxiliary ring 14. Therefore, the hub 4
In the inner end portion, the thickness change in the circumferential direction of the base end portion of the portion forming the caulked portion 18 is large. For this reason, as shown in FIG. 8, when the inner end portion of the hub 4 is caulked and spread radially outward to form the caulked portion 18, the caulked portion 1 is formed.
8 may have excessive stress concentration.

Further, since the inner diameter side male spline portion 17 is formed by cutting with a hob as described above, a part of the outer circumference surface of the hub 4 is processed by the inner diameter side male spline portion 17. Therefore, the width W ₂₈ (FIG. 7) of the relief groove 28 needs to be relatively large. In the case of the conventional structure, as shown in FIGS. 6 to 8, in a state where the inner ring 9 is externally fitted and fixed to the outer peripheral surface of the small-diameter stepped portion 7 provided on the outer peripheral surface of the intermediate portion of the hub 4, The outer end (point Q in FIGS. 7 and 8) is the inner end (FIGS. 7 and 8) of the cylindrical surface portion 29 provided on the inner peripheral surface of the inner ring 9.
8 is located at the same position as the point R), or axially inward of the inner end (right side in FIGS. 6 to 8). The reason for this is that the fitting length between the inner ring 9 and the small-diameter step portion 7 is made sufficiently large,
This is for ensuring a sufficient fitting strength between the inner ring 9 and the small-diameter stepped portion 7.

However, in the conventional structure in which the outer end position of the escape groove 28 is as described above, the fitting strength can be secured, but the width W ₂₈ of the escape groove 28 becomes larger as described above. In addition, there is a possibility that the axial length of the spline engaging portion including the inner diameter side male spline portion 17 and the inner diameter side female spline portion 15 formed on the inner peripheral surface of the auxiliary ring 14 cannot be sufficiently secured. There is. In the case where the axial length of the spline engagement portion cannot be sufficiently ensured in this way, when a large torque is transmitted by the spline engagement portion during use of the wheel drive bearing unit, the spline engagement portion is formed. A large surface pressure is applied to the tooth surfaces of the male and female spline portions 17, 15 on the inner diameter side. For this reason, when the teeth of the spline portions 17 and 15 are worn out or deformed by compression at an early stage, the spline engagement portion is likely to rattle. The occurrence of such rattling is not preferable because it causes an increase in vibration and noise of an automobile in which the wheel drive bearing unit is incorporated. In view of the above circumstances, the present invention prevents damage such as cracks from occurring at a portion forming a caulked portion at an inner end of a hub, and furthermore, a spline coupling between the hub and the coupling member. The present invention has been made to achieve both suppression of rattling at the joint portion and securing of the fitting strength between the hub and the inner ring.

[0012]

A wheel drive bearing unit according to the present invention has an outer ring, a hub, a plurality of rolling elements, and a housing portion, similarly to the above-described conventionally known wheel drive bearing unit. And The outer ring has a first mounting flange on the outer peripheral surface for mounting to the suspension device, and a double-row outer ring raceway on the inner peripheral surface. or,
The hub is provided with a second mounting flange for supporting the wheel at a portion near the outer end of the outer peripheral surface, and a first inner raceway at the central portion, and the outer peripheral surface is also provided at a portion near the inner end. The inner ring forming the second inner ring raceway is externally fitted and fixed. Further, a plurality of rolling elements are provided between the outer raceways and the first and second inner raceways so as to be freely rollable. Further, the housing portion forms a track of a constant velocity joint on an inner peripheral surface thereof, and serves as an outer ring of the constant velocity joint. An outer female spline portion formed on the inner peripheral surface of the outer end portion of the housing portion is spline-engaged with an outer male spline portion formed on the outer peripheral surface of the coupling member. In a state where the connecting member is spline-engaged with the outer peripheral surface near the inner end of the hub, the inner end of the hub is plastically deformed diametrically outward and the inner end surface is suppressed by a caulking portion. , And is fixed to the hub. Further, relative displacement of the coupling member and the housing portion in the axial direction is regulated, so that torque can be freely transmitted from the housing portion to the hub.

In particular, in the wheel drive bearing unit according to the present invention, the hub is formed on the outer peripheral surface near the inner end of the hub, which is spline-engaged with the inner female spline portion formed on the inner peripheral surface of the coupling member. The outer end of the inner diameter side male spline portion, or a part of the outer peripheral surface of the hub, which is provided adjacent to the outer side in the axial direction from the inner diameter side male spline portion, for processing the inner diameter side male spline portion. The outer end of the relief portion is located axially outward of the inner end of the cylindrical surface formed on the inner peripheral surface of the inner ring. Further, before the caulking portion is formed at the inner end of the hub, the coupling member spline-engaged with the outer peripheral surface near the inner end of the hub and the inner ring externally fitted to the hub are moved to the mounting position with respect to the hub. The inner end of the inner diameter side male spline portion is not positioned axially inward of the inner end surface of the coupling member in a state where the inner spline portion is pushed into the inner member.

[0014]

In the case of the wheel drive bearing unit of the present invention configured as described above, a portion of the inner diameter side male spline portion does not exist in the portion forming the caulked portion at the inner end of the hub. Therefore, the concentration of the stress applied to the inner end of the hub during the processing of the caulked portion can be reduced. Therefore, it is possible to prevent the inner end of the hub from being damaged such as a crack. In addition, in the case of the present invention, for example, by forming the inner diameter side male spline portion by plastic working, it is necessary to form a relief portion for processing the inner diameter side male spline portion on a part of the outer peripheral surface of the hub. Or the width of this escape portion can be reduced even if it is formed. Therefore, the fitting length between the inner ring and the hub can be secured. With these, together with the fact that the outer end of the inner diameter side male spline portion or the relief portion is located axially outside the inner end of the cylindrical surface portion provided on the inner peripheral surface of the inner race, the coupling member and the hub At the same time, it is possible to suppress the occurrence of rattling at the spline engagement portion between the inner ring and the inner ring and to secure the fitting strength between the inner ring and the hub.

[0015]

1 to 5 show a first embodiment of the present invention. The feature of the present invention is that the hub 4a
At the inner end portion of the crimping portion 18 to prevent the occurrence of damage such as cracks, and at the same time, the play at the spline engagement portion between the hub 4a and the coupling member (auxiliary ring 14). In order to achieve both the suppression of occurrence and the securing of the fitting strength between the hub 4a and the inner ring 9, a method of processing the inner diameter side male spline portion 17a formed on the outer peripheral surface near the inner end of the hub 4a is devised. That is, the position of both ends is regulated. Since the configuration and operation of the other parts are the same as those of the above-described conventional structure, the same parts are denoted by the same reference numerals, and redundant description will be omitted.

In the case of the wheel drive bearing unit of the present invention,
The inner diameter side male spline portion 17a formed on the outer peripheral surface near the inner end of the hub 4a is formed by plastic working such as rolling or pressing. The inner male spline portion 17a is spline-engaged with the inner female spline portion 15 formed on the inner peripheral surface of the auxiliary ring 14, which is a connecting member.

In the case of this embodiment, a part of the outer peripheral surface of the hub 4a adjacent to the inner side of the inner side male spline portion 17a in the axial direction is provided with the inner side male spline portion 17a.
An escape groove 28a, which is an escape portion for the above-mentioned processing, is formed. However, in the case of this example, unlike the above-described conventional structure, the inner diameter side male spline portion 17a is not formed by cutting, and the escape groove 28a is not for allowing chips to escape. That is, in the case of the present example, the relief groove 28a provided in the hub 4a is provided with a force applied during the processing of the inner diameter side male spline portion 17a in the small diameter step portion 7 provided on the outer peripheral surface of the intermediate portion of the hub 4a. The small-diameter stepped portion 7 is prevented from deforming.

When the inner diameter side male spline portion 17b as described above is formed, for example, as shown in FIG. 2, the outer peripheral surface of the inner end portion of the hub 4a is further outwardly arranged than the small diameter step portion 7 in advance. A second small-diameter step 32 having a smaller diameter is formed. Also, on the outer peripheral surface of the portion near the inner end of the hub 4a, a portion between the second small-diameter stepped portion 32 and the relief groove 28a is provided.
A third small diameter step 33 whose outer diameter is intermediate between the small diameter step 7 and the second small diameter step 32 is formed. When the inner diameter side male spline portion 17a is formed by plastic working such as rolling or pressing, the diameter of the tooth bottom circle of the inner diameter side male spline portion 17a is equal to the diameter of the second small diameter step portion 32. It should be the same as or slightly larger than the outer diameter. In the case of the present invention, the outer end (the point Q 'in FIG. 3) of the clearance groove 28a is fixed to the outer surface of the small-diameter step portion 7 while the inner ring 9 is externally fitted and fixed.
The outer end of the chamfer 30 formed on the inner peripheral surface of the inner end portion of the inner race 9 which is the inner end of the cylindrical surface portion 29 formed on the inner peripheral surface of FIG.
(Point R ′) of FIG. 1 in the axial direction (left side in FIGS. 1 and 3).

Further, in the case of the present invention, as shown in FIG. 4, before the caulking portion 18 is formed at the inner end of the hub 4a, an auxiliary spline engaged with the inner diameter side male spline portion 17a is formed. The outer end surface of the ring 14 and the inner end surface of the inner ring 9 fitted and fixed to the small-diameter step portion 7 abut against each other, and the outer end surface of the inner ring 9 abuts against the step surface of the small-diameter step portion 7 to be attached. Push it to the position
The inner end of the inner diameter side male spline portion 17a (point P in FIG. 4)
′) And the outer end (point S in FIG. 4) of the chamfer 31 formed on the inner peripheral surface of the inner end of the auxiliary ring 14 are regulated so as to be substantially at the same position in the axial direction of the auxiliary ring 14. I have. In this state, the inner end of the hub 4a is plastically deformed outward in the diametrical direction to form a caulked portion 18 at the inner end of the hub 4a, and the auxiliary ring is formed by the caulked portion 18. Hold down the inner end face of 14,
The auxiliary ring 14 is fixed to the inner end of the hub 4a without play.

In the case of the wheel drive bearing unit of the present invention configured as described above, before forming the caulked portion 18, the inner end of the inner diameter side male spline portion 17a is connected to the inner end surface of the auxiliary ring 14. Because it is located more axially outward than
A portion of the inner male spline portion 17a having a large circumferential change in thickness in the portion where the caulking portion 18 is formed at the inner end of the hub 4a is prevented from being present. For this reason, the concentration of the stress applied to the inner end of the hub 4a during the processing of the caulking portion 18 can be reduced. Accordingly, it is possible to prevent the inner end of the hub 4a from being damaged, such as a crack, and to improve the yield of the wheel drive bearing unit.

In particular, in the case of this embodiment, the inner end of the male spline portion 17a on the inner diameter side is connected to the outer end of the chamfer 31 formed on the inner peripheral surface of the inner end portion of the auxiliary ring 14 and the auxiliary ring 1
Since they are provided at substantially the same position in the axial direction of 4, the occurrence of the damage can be more reliably prevented. Moreover, by providing the inner end of the inner diameter side male spline portion 17a at the above-mentioned position, the inner diameter side male spline portion 17a and the inner diameter side female spline portion 15 formed on the inner peripheral surface of the auxiliary ring 14 are formed. A reduction in the length of the spline engagement portion can be minimized. Therefore, in the case of the present example, when the wheel drive bearing unit is used, the surface pressure applied to the tooth surfaces of the spline portions 17a and 15 on the inner diameter side when using the wheel drive bearing unit is kept low, and the spline engagement portion is loosened. The occurrence of sticking can be suppressed.

Further, in the case of the present invention, the inner diameter side male spline portion 17a is formed by plastic working such as rolling or pressing. For this reason, as in this example, even when the relief groove 28a is formed on a part of the outer peripheral surface of the hub 4a,
The escape groove 28a is formed in the male spline portion 17a on the inner diameter side.
Any shape can be used as long as the small-diameter stepped portion 7 provided on the outer peripheral surface of the intermediate portion of the hub 4a can be prevented from being deformed based on the force applied at the time of processing. For this reason, the width W of the escape groove 28a
_28a is the width W ₂₈ of the clearance groove 28 in the case of the conventional structure (FIG. 7).
(W _28a <W ₂₈ ). Therefore, according to the present invention, the outer end of the clearance groove 28a is positioned axially outside the inner end of the cylindrical surface portion 29 provided on the inner peripheral surface of the inner ring 9, so that the inner ring 9 While ensuring a sufficient fitting length between the auxiliary ring 14 and the hub 4a,
, The axial length of the spline engagement portion between them can be increased. As a result, it is possible to achieve both high-dimensional suppression of rattling at the spline engagement portion and securing of the fitting strength between the inner ring 9 and the hub 4a.

In the case of this embodiment, a relief portion for machining the male spline portion 17a on the inner diameter side is provided in a part of the outer peripheral surface of the hub 4a. However, the present invention is not limited to such a structure. However, when the present invention is applied to a structure in which no relief portion is provided on the outer peripheral surface of the hub, the outer end of the inner diameter side male spline portion is positioned more axially outward than the inner end of the cylindrical surface portion provided on the inner peripheral surface of the inner ring. It is regulated to be located in. Therefore, in this case, the length of the spline engagement portion between the hub and the auxiliary ring can be further increased as compared with the case of the present example, and the occurrence of rattling at the spline engagement portion can be further reduced. Can be suppressed sufficiently.

Further, in this embodiment, the present invention is applied to a structure in which the coupling member is an auxiliary ring formed separately from the inner ring, and the outer end surface of the auxiliary ring and the inner end surface of the inner ring abut against each other. However, the present invention is not limited to such a structure, and the coupling member is formed integrally with the inner ring, and protrudes from the inner end surface of the inner ring toward the inner diameter side of the housing portion. Even for a structure that is a cylindrical part,
Can be applied. In such a structure, an inner diameter side female spline portion is formed on the inner peripheral surface of the cylindrical portion. And
The inner ring is fitted to a small-diameter step portion formed on the outer peripheral surface of the intermediate portion of the hub by interference fit, and the inner female spline portion is spline-engaged with the inner male spline portion formed on the outer peripheral surface of the hub. Even when the present invention is applied to such a structure, damage such as cracks is prevented from occurring in the portion forming the caulked portion at the inner end of the hub, and furthermore, the gap between the hub and the cylindrical portion is prevented. It is possible to achieve both suppression of rattling at the spline engagement portion and securing of fitting strength between the hub and the inner ring.

[0025]

Since the wheel drive bearing unit according to the present invention is constructed and operates as described above, it is possible to prevent the occurrence of damage such as cracks at the portion forming the caulked portion at the inner end of the hub. In addition, it is possible to achieve both high-dimensional suppression of rattling at the spline engagement portion between the hub and the coupling member and securing of fitting strength between the hub and the inner ring. As a result, it is possible to realize a wheel drive bearing unit that can improve the yield and has excellent durability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing an inner end portion of the hub in a state before an inner diameter side male spline portion is formed.

FIG. 3 is an enlarged view of a portion A in FIG. 1;

FIG. 4 is a partial cross-sectional view showing a spline engaging portion between an outer peripheral surface of an inner end portion of the hub and an inner peripheral surface of an auxiliary ring before a caulked portion is formed in the present invention.

FIG. 5 is an enlarged view of a portion B in FIG. 1;

FIG. 6 is a sectional view showing an example of a conventional structure.

FIG. 7 is a partial cross-sectional view showing a spline engagement portion between an inner peripheral surface of an inner end portion of a hub and an inner peripheral surface of an auxiliary ring before forming a caulked portion in an example of a conventional structure.

FIG. 8 is an enlarged view of a portion C in FIG. 6;

[Explanation of symbols]

 Reference Signs List 1 outer ring 2 first mounting flange 3 outer ring track 4, 4a hub 5 second mounting flange 6 first inner ring track 7 small diameter stepped portion 8 second inner ring track 9 inner ring 10 rolling element 11 seal ring 12 constant velocity joint 13 Housing part 14 Auxiliary ring 15 Inner diameter side female spline part 16 Outer diameter side male spline part 17, 17a Inner diameter side female spline part 18 Caulking part 20 Outer diameter side female spline part 21 Ball 22 Engagement groove 23 Retaining ring 24 Inner engagement groove Reference Signs List 25 outer locking groove 26 cap 27 inner ring for constant velocity joint 28, 28a relief groove 29 cylindrical surface part 30 chamfer 31 chamfer 32 second small diameter step 33 third small diameter step

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F16D 1/06 F16D 3/20 Z 3/20 1/06 Q

Claims (3)

[Claims] 1. An outer ring having a first mounting flange for mounting to a suspension device on an outer peripheral surface, a double row of outer ring raceways on an inner peripheral surface, and a wheel supported on a portion of the outer peripheral surface near an outer end. A second mounting flange, also provided with a first inner raceway in the center portion, respectively, and a hub in which an inner race having a second inner raceway formed on the outer peripheral surface thereof is similarly fixed to a portion near the inner end, and a hub, A plurality of rolling elements provided so as to freely roll between each of the outer ring raceways and the first and second inner raceways, and a constant velocity joint track formed on an inner peripheral surface thereof; And a housing part that becomes an outer ring of
An outer diameter side female spline portion formed on the inner peripheral surface of the outer end portion of the housing portion and the inner end portion of the hub are plastically diametrically outwardly engaged with a spline on the outer peripheral portion near the inner end of the hub. The outer end side male spline portion formed on the outer peripheral surface of the coupling member fixed to the hub with its inner end surface held down by a caulked portion formed by deformation is spline-engaged, and the coupling member and the housing portion are joined together. In the wheel drive bearing unit which regulates the relative displacement in the axial direction with respect to the shaft portion and freely transmits the torque from the housing portion to the hub, an inner diameter side female spline formed on the inner peripheral surface of the coupling member is provided. The outer end of the inner diameter side male spline portion formed on the outer peripheral surface near the inner end of the hub, or a part of the outer peripheral surface of the hub, in the axial direction outside of the inner diameter side male spline portion. next to The outer end of the escape portion for processing the inner diameter side male spline portion provided in a state where the inner surface of the inner ring is located outside the inner end of the cylindrical surface portion formed on the inner peripheral surface of the inner ring, and Before the caulking portion is formed at the inner end of the hub, the coupling member spline-engaged with the outer peripheral portion near the inner end of the hub and the inner ring externally fitted to the hub are pushed to the mounting position on the hub. In this state, the inner end of the inner diameter side male spline portion is not located axially inward of the inner end surface of the coupling member. 2. The wheel driving device according to claim 1, wherein the coupling member is an auxiliary ring formed separately from the inner ring, and an outer end surface of the auxiliary ring and an inner end surface of the inner ring abut against each other. Bearing unit. 3. The wheel drive bearing unit according to claim 1, wherein the coupling member is formed integrally with the inner race, and is a cylindrical portion protruding from the inner end surface of the inner race toward the inner diameter side of the housing.