JP2002061663A - Bearing unit for wheel drive - Google Patents

Abstract

(57) Abstract: A structure capable of easily connecting a hub (4b) and a drive shaft member (18c), and slightly suppresses axial displacement between these two members (4b, 18c). Further, the wear of the hub side spline engagement portion 50 is prevented, and the seal ring 38 a
To ensure the durability. A retaining ring (33a) is engaged between an engaging groove (32) on a drive shaft member (18c) side and an engaging step (36) on a hub (4b) to join the two members (4b, 18c) together. Hub 4b
The axial displacement between the two members 4b and 18c is suppressed by the engagement between the step receiving portion 44 on the side and the pushing step 47 on the driving shaft member 18c side. Since the dimensional accuracy of the two step portions 44 and 47 can be easily ensured, the above problem can be solved. The above problem can be solved by slightly suppressing the axial displacement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a so-called 3.5th-generation hub unit, which is a so-called 3.5th-generation hub unit, in which a constant velocity joint and a hub unit are integrated. In particular, the drive wheels supported by the independent suspension type: the front wheels of the FF vehicle (front engine front wheel drive vehicle), F
All the wheels 、 ４ of the R car (front-engine rear-wheel drive vehicle) and the RR car (rear-engine rear-wheel drive vehicle) and the 4WD car (four-wheel drive vehicle) are rotatably supported by the suspension system. Along with
It is used to rotationally drive the drive wheels. In other words, in order to support the drive wheels supported by the independent suspension type suspension on the suspension device and to rotationally drive the wheels, the hub unit and the differential constant velocity joint and the hub constant velocity at both ends of the transmission shaft, respectively. A drive unit for a wheel is used in combination with a constant velocity joint unit in which a joint is connected. A wheel drive bearing unit to which the present invention is applied is a combination of a hub unit and a hub-side constant velocity joint that constitute such a wheel drive unit.

[0002]

2. Description of the Related Art In order to rotatably support wheels with respect to a suspension device, various types of wheel supporting bearing units in which an outer ring and an inner ring are rotatably combined via rolling elements have been used. In addition, the wheel supporting bearing unit that supports the drive wheels on the independent suspension type suspension is combined with a constant velocity joint, regardless of the relative displacement between the differential gear and the drive wheels and the steering angle given to the wheels. It is necessary to transmit the rotation to the wheels smoothly (with constant speed). FIG. 3 shows a general wheel drive bearing unit combining such a wheel support bearing unit 1 and a constant velocity joint 2.

[0003] Of these, the wheel supporting bearing unit 1 is
A hub 4 and an inner ring 5 are rotatably supported on the inner diameter side of the outer ring 3 via a plurality of rolling elements 6, 6. Of these, the outer ring 3 does not rotate during use in a state where the outer ring 3 is connected and fixed to a knuckle 8 (see FIG. 4 described later) constituting a suspension device by a first flange 7 provided on an outer peripheral surface thereof. Further, double rows of outer raceways 9 are provided on the inner peripheral surface of the outer race 3, and the hub 4 and the inner race 5 are supported concentrically with the outer race 3 on the inner diameter side of the outer race 3.

[0004] Of these hubs, a hub 4 is provided for supporting wheels at an outer end portion of the outer peripheral surface (an end which becomes the outer side in the width direction of the vehicle when assembled to an automobile, the left end in FIGS. 1 to 5). A second flange 10 is provided. Also, a first inner raceway 11 is formed at an intermediate portion of the outer peripheral surface of the hub 4 and is similarly an inner end (an end which is a center side in the width direction of the vehicle in a state of being assembled to the vehicle, a right end in FIGS. 1 to 5). The inner ring 5 having a second inner raceway 13 formed on the outer peripheral surface thereof is externally fitted and fixed to the small-diameter stepped portion 12 formed in the portion. A first spline hole 14 is provided in the center of the hub 4.

On the other hand, the constant velocity joint 2 includes an outer ring 15 for a constant velocity joint, an inner ring 16 for a constant velocity joint, and a spline shaft 17. The constant-velocity joint outer race 15 and the spline shaft 17 constitute a drive shaft member 18. That is, the spline shaft 17 is provided at the outer end of the drive shaft member 18 and is freely engageable with the first spline hole 14.
Is provided at the inner end of the drive shaft member 18. Outer engagement grooves 19 are formed at a plurality of circumferential positions on the inner circumferential surface of the outer race 15 for constant velocity joints, respectively, in a direction perpendicular to the circumferential direction. Further, the inner race 16 for a constant velocity joint has a second spline hole 20 at a central portion, and inner engagement grooves 21, 21 at portions corresponding to the outer engagement grooves 19, 19 on the outer peripheral surface thereof, respectively. It is formed at right angles to the circumferential direction. And each of these inner engagement grooves 2
Balls 22, 22 are provided between the outer grooves 1, 19 and the outer engagement grooves 19, 19, respectively, while being held by a retainer 23, so as to freely roll along the respective engagement grooves 21, 19.
The shape and the like of each component of the constant velocity joint 2 are the same as those of the well-known Zeppa type or Barfield type constant velocity joint, and are not related to the gist of the present invention. Is omitted.

The constant velocity joint 2 as described above and the wheel bearing rolling bearing unit 1 as described above insert the spline shaft 17 into the first spline hole 14 of the hub 4 from inside to outside. . And the spline shaft 1
A nut 25 is screwed into a male screw portion 24 provided at a portion protruding from the outer end surface of the hub 4 at the outer end of the hub 7, and the nut 25 is further tightened to be connected and fixed to each other. In this state, the inner end face of the inner ring 5 comes into contact with the outer end face of the outer ring 15 for a constant velocity joint, so that the inner ring 5 is not displaced in the direction of coming out of the small diameter step portion 12. At the same time, an appropriate preload is applied to each of the rolling elements 6,6.

Further, when assembled to the suspension system of the automobile, the male spline portion 27 provided at the outer end of the drive shaft 26 is inserted into the second spline hole 20 provided at the center of the inner ring 16 for the constant velocity joint. Are spline-engaged. Then, a retaining ring 29 locked in a locking groove 28 formed over the entire outer peripheral surface of the outer end portion of the male spline portion 27 is formed at the outer peripheral edge of the outer end opening of the second spline hole 20. The male spline portion 27 is prevented from falling out of the second spline hole 20 by engaging with the locking step portion 30.
The inner end of the drive shaft 26 is fixedly connected to the center of the trunnion of a tripod constant velocity joint (not shown) provided on the output shaft of a differential gear (not shown). Therefore, the drive shaft 26 rotates at a constant speed when the vehicle is running, and a thrust load in both directions in the axial direction is repeatedly applied with the rotation based on the resistance of the tripod-type constant velocity joint.

Although the drawing does not show a differential constant velocity joint provided at the output portion of the differential gear, the differential end constant velocity joint, such as a tripod type, is provided at the inner end of the drive shaft 26. The output of the speed joint is connected. The tripod-type constant velocity joint, the drive shaft 26, and the constant velocity joint 2 constitute the constant velocity joint unit described above. In a state before being assembled to an automobile, the constant velocity joint unit and the wheel supporting bearing unit 1 are combined to form the above-described wheel drive unit.

In the wheel driving bearing unit shown in FIG. 3, the wheel supporting rolling bearing unit 1 and the constant velocity joint 2 are connected and fixed based on the screwing / tightening of the male screw portion 24 and the nut 25. Weight increases. That is, the male screw portion 2 is attached to the spline shaft 17 on the constant velocity joint 2 side.
4, the length of the spline shaft 17 needs to be increased, and the nut 25 is required. Therefore, the axial dimension and weight of the wheel drive bearing unit are increased by the amount of the male screw portion 24 and the nut 25.

[0010] In contrast, US Pat.
As shown in FIG. 4, the specification discloses a structure in which the wheel supporting bearing unit and the constant velocity joint are connected and fixed with a simpler structure to reduce the axial dimension and the weight. Has been described. Also in the second example of the conventional structure shown in FIG. 4, the hub 4 is rotatably supported inside the outer ring 3 fixed to the knuckle 8 by the rolling elements 6, 6 arranged in a double row. The spline shaft 17 of the drive shaft member 18a is spline-engaged with the first spline hole 14 formed in the center of the hub 4. On the outer end surface of the spline shaft 17, a locking portion 31 for locking a tool for drawing the spline shaft 17 into the first spline hole 14 is formed. The spline shaft 17 is prevented from slipping out of the hub 4 by a retaining ring 33 locked in a locking groove 32 formed in a portion of the spline shaft 17 near the front end of the outer peripheral surface. In this state,
The elastic ring 34 is elastically compressed between the hub 4 and the outer race 15 for the constant velocity joint of the drive shaft member 18a to prevent rattling between the spline shaft 17 and the hub 4. In the case of the second example of such a conventional structure, the coupling between the wheel supporting bearing unit 1a and the constant velocity joint 2a is performed by the retaining ring 33, so that the wheel driving bearing unit as a whole is reduced in size and weight. Can be achieved.

[0011]

DESCRIPTION OF THE PRESENT INVENTION In the case of the second example of the conventional structure as described above,
On the other hand, while the size and weight can be reduced, it is difficult to ensure sufficient durability as it is because the elastic ring 34 is easily deflected and the fatigue strength of each part is unbalanced. In view of such circumstances, the present inventor has previously proposed a wheel drive bearing unit that can effectively secure sufficient durability even when the connection between the wheel support bearing unit and the constant velocity joint is performed by a retaining ring. (Japanese Patent Application 2000-)
37656). The wheel drive bearing unit of this invention will be described with reference to FIG.

In the case of the wheel drive bearing unit according to the preceding invention, in order to prevent the inner ring 5 externally fitted to the small diameter step 12 formed at the inner end of the hub 4a from falling out of the small diameter step 12. A caulked portion 35 is formed at the inner end of the hub 4a. That is, a cylindrical portion is formed at the inner end of the hub 4a, and the inner ring 5 is externally fitted to the small-diameter step portion 12, and then the cylindrical portion is plastically deformed radially outward to form the caulking portion 3.
5 is formed, and the inner end surface of the inner ring 5 is suppressed by the caulking portion 35.

An engaging groove 32 corresponding to the inner diameter side engaging portion is formed in the front end portion (outer end portion) of the spline shaft 17a constituting the drive shaft member 18b over the entire circumference. Has formed. In a state where the spline shaft 17a is inserted into the first spline hole 14 provided in the center of the hub 4a, the outer peripheral side of the retaining ring 33a in which the inner half of the retaining ring is retained in the retaining groove 32. A half portion is engaged with a locking step 36 corresponding to an outer diameter side engaging portion defined in a portion near an outer end of the inner peripheral surface of the hub 4a, so that the spline shaft 17a is mounted on the hub 4a. It is prevented from falling out of the first spline hole 14. The locking step 3 is inserted into the center hole of the hub 4a.
The portion closer to the opening on the outer end side than 6 does not form a spline but has a simple cylindrical surface.

The retaining ring 33a is mounted in the locking groove 32 before the spline shaft 17a is inserted into the first spline hole 14. When the spline shaft 17a is inserted into the first spline hole 14, the retaining ring 33a passes through the first spline hole 14 while elastically reducing its diameter. Then, after passing through, it is elastically restored, and as described above, the locking groove 3
2 and between the locking step 36. For this reason, the groove bottom diameter of the locking groove 32 is made sufficiently small.

An opening at the outer end of the center hole of the hub 4a is closed by a cap 37. On the other hand, a seal ring 38 is provided between the inner surface of the caulking portion 35 and the outer end surface of the outer race 15 for a constant velocity joint in a state of being elastically compressed between these two surfaces. 35
And the outer ring 15 for constant velocity joints. The cap 37 and the seal ring 38 prevent foreign matter such as rainwater from entering the hub-side spline engagement portion 50 between the spline shaft 17a and the first spline hole 14, and the hub-side spline The engagement portion 50 is prevented from rusting.

As described above, the retaining ring 33a prevents the spline shaft 17a from coming out of the first spline hole 14, and the inner surface of the caulked portion 35 and the outer end surface of the outer race 15 for the constant velocity joint. Seal ring 38 between
In the state where is mounted, there is a gap between the inner surface of the caulking portion 35 and the step portion 40 formed on the intermediate outer surface of the drive shaft member 18b. However, the size of this gap in the thrust direction is suppressed to 0.8 mm or less, and the hub-side spline engagement portion 5 is not affected by the displacement based on the thrust load applied during traveling.
0 is prevented, and the seal ring 38 is prevented from being excessively compressed. That is, when the assembly of the wheel drive bearing unit is completed, the relative displacement of the hub 4a and the drive shaft member 18b in the axial direction is slightly suppressed, and the wear of the hub side spline engagement portion 50 is reduced. In addition, the seal ring 38 is prevented from being damaged.

Further, in the case of the wheel drive bearing unit according to the invention, the base end (inner end) of the spline shaft 17a.
Is smaller than the groove bottom diameter of the male spline portion 27 formed at the outer end of the drive shaft 26. That is, at the base end of the spline shaft 17a, a constriction 39 having a diameter slightly smaller than the groove bottom diameter of the male spline is formed at the base end of the spline shaft 17a for escape when forming a male spline by broaching or the like. are doing. In this case,
The outer diameter D ₃₉ of the constricted portion 39 is determined by the male spline portion 2
Than the groove bottom diameter D ₂₇ of 7, the range of 1 to 3 mm, preferably by about 2mm greater _{(D 39 ≒ D 27 + 2mm} ). These dimensions are shown in the case of a wheel drive device for a general passenger car.

According to the bearing unit for driving a wheel of the present invention constructed as described above, the bearing unit 1b for supporting the wheel and the constant velocity joint 2a are connected by the retaining ring 33a, so that the structure can be reduced in size and weight. In use, the strength of the spline shaft 17a constituting the drive shaft member 18b can be secured. That is, since the outer diameter of the weakest portion 39 provided at the base end of the spline shaft 17a is weakened, the strength of the narrow portion 39 is larger than the strength of the outer end of the drive shaft 26. Can also be prevented from being significantly inferior. Because of this,
The durability of some of the components of the wheel drive bearing unit is
It is possible to prevent remarkably inferior durability compared with other parts, and to ensure the durability of the entire wheel drive bearing unit regardless of the bending moment applied repeatedly during use.

[0019]

In the case of the wheel drive bearing unit according to the prior invention as described above, the shaft of the hub 4a and the drive shaft member 18b in a state where the assembly of the wheel drive bearing unit is completed. It is difficult to reliably maintain the relative displacement in the direction to a small extent. The reason for this is that the relative displacement amount is suppressed by causing the inner surface of the caulking portion 35 formed on the hub 4a side and the step portion 40 provided on the drive shaft member 18b to be in close proximity to each other. It is.
Of the caulking portion 35 and the step portion 40, the step portion 40 can secure sufficient dimensional accuracy by turning or the like, but the caulking portion 35 is formed by gradually plastically deforming by rocking. However, it is difficult to secure the dimensional accuracy in units of 0.1 mm because the processing is not performed using a mold whose axial dimension is determined.

On the other hand, if the caulking portion 35 and the step portion 40 abut before the retaining ring 33a is bridged between the locking groove 32 and the locking step portion 36, the wheel drive bearing unit is assembled. Therefore, it is necessary to provide a slight gap between the caulking portion 35 and the step portion 40. Considering these facts, the caulked portion 35 and the stepped portion 4 are assembled in a state where the assembly of the wheel drive bearing unit is completed.
0, the axial dimension of the gap existing between 0.2 and 0.2.
It varies within a range of about 0 mm. If the axial dimension of the gap greatly exceeds 0.8 mm based on such a variation, the wear of the hub-side spline engagement portion 50 becomes not only negligible but also the seal ring. 38 is over-compressed and this seal ring 3
8 is impaired in durability. In view of such circumstances, the present invention suppresses the relative displacement in the axial direction between the hub and the drive shaft member, effectively prevents the wear of the hub-side spline engagement portion 50, and further reduces the hub-side spline engagement. The present invention was invented to ensure the durability of a seal ring for sealing the portion 50.

[0021]

A bearing unit for driving a wheel according to the present invention comprises an outer ring, a hub, a rolling element, a drive shaft member, a retaining ring, a seal ring, first and second step portions. And Of these, the outer ring has a first flange on the outer peripheral surface for coupling and fixing to the suspension device, and a double-row outer ring raceway on the inner peripheral surface, and does not rotate during use. Further, the hub has a second flange for supporting the wheel at a portion near the outer end of the outer peripheral surface, a first inner ring raceway directly at the intermediate portion or via a separate inner ring, and a spline at the center portion. Holes are provided respectively. At the same time, an inner ring having a second inner raceway formed on its outer peripheral surface is fitted around the inner peripheral portion of the outer peripheral surface,
The inner end surface of the inner ring is held down and fixed by a caulking portion formed by plastically deforming the inner end portion radially outward. In addition, a plurality of rolling elements are provided between the outer raceways and the first and second inner raceways so as to be capable of rolling in plurals. In the drive shaft member, a spline shaft that engages with the first spline hole is provided at an outer end, and an inner end is an outer race for a constant velocity joint that forms a constant velocity joint. Further, the retaining ring has an inner diameter side engaging portion provided on an outer peripheral surface of an outer end portion of the spline shaft and an outer diameter side provided on a portion of the inner peripheral surface of the hub opposed to the inner diameter side engaging portion. The spline shaft is hung between the engaging portions to prevent the spline shaft from falling out of the spline hole. The seal ring is sandwiched between the inner surface of the caulked portion and the outer end surface of the outer race for a constant velocity joint. Further, among the first and second steps, the first step is formed in a state facing inward at a portion located on the inner diameter side of the inner ring on the inner peripheral surface of the hub, The second step is
The spline shaft is formed on the base outer peripheral surface so as to face outward. Then, based on the engagement between the first and second steps, the drive shaft member is prevented from being displaced relative to the hub in a direction that excessively compresses the seal ring.

[0022]

In the case of the wheel drive bearing unit of the present invention configured as described above, both the first and second steps can be turned or axially dimensioned. It can be formed by a processing method that can easily obtain a high degree of dimensional accuracy, such as forging performed by applying a mold. For this reason, in the state where the assembly of the wheel drive bearing unit is completed, the reliability of minimizing the relative displacement in the axial direction between the hub and the drive shaft member is improved, and the spline between the spline hole and the spline shaft is improved. It is possible to prevent wear of the engaging portion and ensure durability of the seal ring.

[0023]

FIG. 1 shows a first embodiment of the present invention. Although the drawing does not show a differential-side constant velocity joint provided at the output portion of the differential gear, a drive shaft 26 having an outer end coupled and fixed to the constant velocity joint inner ring 16 constituting the illustrated constant velocity joint 2a is shown. The output end of the tripod type constant velocity joint, which is the differential constant velocity joint, is connected to the inner end of the constant velocity joint. The tripod-type constant velocity joint, the drive shaft 26, and the constant velocity joint 2a constitute the constant velocity joint unit described above. In a state before being assembled to an automobile, the constant velocity joint unit and the wheel supporting bearing unit 1 are combined to form the above-described wheel drive unit.

A feature of the present invention is to increase the certainty that the relative displacement of the hub 4b and the drive shaft member 18c in the axial direction after the assembly of the wheel drive bearing unit is completed is suppressed to a small extent. There is in the structure for. The structure and operation of the other parts are the same as the second example of the conventional structure shown in FIG. 4 or the structure of the prior invention shown in FIG.
The same parts are denoted by the same reference numerals, and overlapping description will be omitted or simplified. Hereinafter, description will be made focusing on the features of the present invention.

At the inner end of the center hole 41 formed in the hub 4b, a small-diameter cylindrical portion having a diameter slightly larger than the diameter of the root circle of the first spline hole 14 provided at an intermediate portion of the center hole 41. 42 and a large-diameter cylindrical portion 4 having a larger diameter than the small-diameter cylindrical portion 42.
3 are provided in order from the side of the first spline hole 14 concentrically with each other. The small-diameter cylindrical portion 42 and the large-diameter cylindrical portion 43 are connected to each other by a conical concave-shaped receiving portion 44, which is the first step described in the claims.
The receiving portion 44 is present on the inner diameter side of the inner race 5 which is externally fitted and fixed to the inner end of the hub 4b. In other words, the axial position of the step receiving portion 44 is between both end surfaces in the axial direction of the inner ring 5 shown by L in FIG.

On the other hand, on the outer peripheral surface of the base end portion (inner end portion) of the spline shaft 17b constituting the drive shaft member 18c, an inner small diameter which is a little smaller than the small diameter cylindrical portion 42 and also serves as a constricted portion 39 is provided. A male spline portion 5 is formed by concentrically connecting a cylindrical portion 45 and an inner large-diameter cylindrical portion 46 having a diameter larger than the small-diameter cylindrical portion 42 and slightly smaller than the large-diameter cylindrical portion 43.
1 in that order. The inner small-diameter cylindrical portion 45 and the inner large-diameter cylindrical portion 46 are connected to each other by a conical convex pressing step 47 which is a second step described in the claims. The inclination angle of the pushing step 47 and the inclination angle of the receiving step 44 are made to coincide with each other. Therefore,
These two step portions 47 and 44 can freely contact each other over the entire circumference.

In order to assemble the wheel drive bearing unit of the present invention, the spline shaft 17b is inserted into the first spline hole 14, and the retaining ring 33a is inserted between the locking groove 32 and the locking step portion 36. In the state of being bridged, the caulking portion 35
The seal ring 38a is elastically compressed between the outer ring 15 and the outer ring 15 for the constant velocity joint. In the illustrated example, the leading edge of the seal lip 48 constituting the seal ring 38a is elastically attached to the inner surface of the caulked portion 35 over the entire circumference by a tightening margin of about 0.2 to 1.0 mm. Abutting.

In this state, the pushing step 47 and the receiving section 44 are closely opposed to each other over the entire circumference. There is a larger gap between the caulking portion 35 and the step portion 40 of the drive shaft member 18c than the gap between the two step portions 47 and 44. Therefore, these two steps 47,
The caulking portion 35 and the step portion 40 do not abut before the abutments 44 abut each other.

When the above-described wheel drive bearing unit of the present invention is mounted on an automobile and used, the two members 4b and 18c are connected between the hub 4b and the drive shaft member 18c as the vehicle travels. A thrust load is applied to make relative displacement in the direction. However, regardless of such a thrust load, the displacement between the two members 4b and 18c is slightly suppressed. For example, the drive shaft member 1 is
In the case where the outer ring 8c is to be displaced rightward in FIG. 1, the displacement is prevented by the outer half of the retaining ring 33a abutting against the locking step 36. On the other hand, when the drive shaft member 18c is to be displaced leftward in FIG. 1 with respect to the hub 4b, the pushing step 47 and the receiving step 44 abut against each other, so that this displacement is reduced. Block.

The pushing step 47 and the receiving section 44 are
In any case, turning or dimensioning in the axial direction can be performed.
It can be formed by a processing method that can easily obtain a high degree of dimensional accuracy, such as forging performed by applying a die. Therefore, it is possible to increase the certainty that the relative displacement in the axial direction between the hub 4b and the drive shaft member 18c in the state where the assembly of the wheel drive bearing unit is completed is slightly suppressed.
Therefore, the amount of axial displacement between the first spline hole 14 and the spline shaft 17b is slightly suppressed, and wear of the spline engagement portion between the first spline hole 14 and the spline shaft 17b can be prevented. The seal ring 3
8a is prevented from being excessively compressed, the durability of the seal ring 38a is secured, and the sealing performance of the spline engagement portion can be secured.

In the case of the present invention, the pressing step 47
And the step receiving portion 44 are provided on the inner diameter side of the inner ring 5, so that these step portions 47 and 44 are formed,
The axial dimension of the wheel drive bearing unit does not increase.
On the other hand, if the two step portions 47 and 44 are provided outside the outer end surface of the inner ring 5, the first spline hole 14
In consideration of securing the length of the spline engagement portion between the hub 4b and the spline shaft 17b, the axial dimension of the hub 4b and the drive shaft member 18c increases, and the wheel drive bearing unit becomes large. Become In the case of the present invention, it is possible to prevent the abrasion and ensure the sealing performance while preventing such an increase in size.

FIG. 2 shows a second embodiment of the present invention.
An example is shown. In the case of the present example, a cylinder having a diameter slightly larger than the diameter of the root circle of the first spline hole 14 provided in the middle of the center hole 41a is formed at the inner end of the center hole 41a formed in the hub 4c. A portion 49 is formed, and the cylindrical portion 49 and the first spline hole 14 are connected to each other by a conical concave receiving portion 44a which is a first step portion described in the claims. On the other hand, at the base of the spline shaft 17c constituting the drive shaft member 18d, a pushing step 47a is formed at a portion facing the receiving step 44a. The structure of this example is
Compared to the structure of the first example described above, the first spline hole 14 and the male spline portion 51 of the spline shaft 17c are provided.
This facilitates the design to increase the axial length of the hub side spline engagement portion 50. Other configurations and operations are
Since this is the same as the case of the first example described above, the same parts are denoted by the same reference numerals, and redundant description will be omitted.

[0033]

The bearing unit for driving a wheel according to the present invention is constructed and operated as described above. Therefore, the coupling between the bearing unit for supporting the wheel and the constant velocity joint is performed by a retaining ring, so that the structure can be reduced in size and weight. Thus, excellent durability can be ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first example of an embodiment of the present invention.

FIG. 2 is a sectional view showing the second example.

FIG. 3 is a sectional view showing a first example of a conventional structure.

FIG. 4 is a sectional view showing the second example.

FIG. 5 is a sectional view showing an example of a structure according to the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a, 1b Wheel supporting bearing unit 2, 2a Constant velocity joint 3 Outer ring 4, 4a, 4b, 4c Hub 5 Inner ring 6 Rolling element 7 First flange 8 Knuckle 9 Outer ring raceway 10 Second flange 11 First Inner ring raceway 12 Small diameter step 13 Second inner ring raceway 14 First spline hole 15 Outer ring for constant velocity joint 16 Inner ring for constant velocity joint 17, 17a, 17b, 17c Spline shaft 18, 18a, 18b, 18c, 18d Drive shaft Member 19 Outer engagement groove 20 Second spline hole 21 Inner engagement groove 22 Ball 23 Cage 24 Male screw part 25 Nut 26 Drive shaft 27 Male spline part 28 Lock groove 29 Retaining ring 30 Lock step 31 Lock part 32 locking groove 33, 33a retaining ring 34 elastic ring 35 caulking portion 36 locking step 37 cap 38, 38a Ring 39 Constriction part 40 Step part 41, 41a Center hole 42 Small diameter cylindrical part 43 Large diameter cylindrical part 44, 44a Step receiving part 45 Inner small diameter cylindrical part 46 Inner large diameter cylindrical part 47, 47a Push step part 48 Seal lip 49 Cylindrical surface part 50 Hub side spline engagement part 51 Male spline part

Claims (1)

[Claims] An outer ring which has a first flange for coupling and fixing to a suspension device on an outer peripheral surface, a plurality of rows of outer ring raceways on an inner peripheral surface, and which does not rotate during use, and an outer end of the outer peripheral surface. The second flange for supporting the wheel in the deviated part, the first inner ring track also in the middle part directly or via a separate inner ring,
A spline hole is provided at the center, and an inner ring having a second inner raceway formed on its outer peripheral surface is fitted around the inner end of the outer peripheral surface, and the inner end is plastically deformed radially outward. A hub having the inner end surface of the inner ring held down and fixed by a caulking portion configured in this way, and a plurality of rolls are respectively provided between each of the outer ring raceways and the first and second inner ring raceways so as to freely roll. A driving shaft member having an outer end provided with a spline shaft engaging with the first spline hole, and an inner end serving as an outer race for a constant velocity joint which constitutes a constant velocity joint; Between the inner diameter side engaging portion provided on the outer peripheral surface of the outer end portion and the outer diameter side engaging portion provided on a portion of the inner peripheral surface of the hub opposed to the inner diameter side engaging portion. To prevent the spline shaft from coming out of the spline hole. A retaining ring to be stopped, a seal ring sandwiched between an inner surface of the caulked portion and an outer end surface of the outer race for a constant velocity joint, and a portion located on the inner peripheral surface of the inner race on the inner peripheral surface of the hub. A first step formed in a state facing inward, and a second step formed in a state facing outward on a base outer peripheral surface of the spline shaft, these first,
A wheel drive bearing unit that prevents the drive shaft member from being displaced relative to the hub in a direction that excessively compresses the seal ring based on engagement between the second step portions.