JP2002172907A - Bearing unit for wheel drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute structure at a low cost without using an expensive part item and besides to realize a structure so that uncomfortable vibration and noise are prevented from occurring. SOLUTION: A retaining ring 22a is locked between a lock groove 29 on the outside diameter side formed in the outer peripheral surface of a spline hole 15b and a lock groove 28 on the inside diameter side formed in the outer peripheral surface of a spline shaft 17b and separation between a hub 4b and a drive shaft member 16b is prevented from occurring. By regulating the widths of the lock grooves 29 and 28 on the outside diameter side and on the inside diameter side and the diameter of a wire of which the retaining ring 22a is formed, an amount of movement in the axial direction of the hub 4b and the drive shaft member 16b is suppressed to 1.0 mm or less. This constitution solves a problem described above.

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 wheel support bearing unit are integrated, and a drive wheel ｛FF vehicle (front type) supported by an independent suspension type suspension. Engine with front-wheel drive)
Of the front wheels, rear wheels of FR vehicles (rear-wheel drive vehicle with front engine) and RR vehicles (rear-wheel drive vehicle of rear engine), and all wheels of 4WD vehicle (four-wheel drive vehicle) can be freely rotated with respect to the suspension system. And used to rotationally drive the drive wheels. That is, in order to support the driving wheels on the independent suspension type and to rotate the driving wheels, a wheel supporting bearing unit, and a differential constant velocity joint and a wheel constant velocity joint at both ends of the driving shaft, respectively. A drive unit for a wheel is used in combination with a constant velocity joint unit to which the above-mentioned is coupled. The wheel drive bearing unit to which the present invention is applied is a combination of a wheel support bearing unit and a wheel side constant velocity joint which 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 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, various wheel drive bearing units combining a wheel support bearing unit and a constant velocity joint have been used for such a purpose. In addition, various structures have been proposed to reduce the weight and cost of the wheel drive bearing unit by connecting the wheel support bearing unit and the constant velocity joint without using a nut. I have.

FIG. 7 shows a first example of a conventional structure described in US Pat. No. 4,881,842. This wheel drive bearing unit comprises a wheel support bearing unit 1
And the constant velocity joint 2. The wheel supporting bearing unit 1 includes a hub 4 and an inner ring 5 rotatably supported on the inner diameter side of the outer ring 3 via a plurality of rolling elements 6. The outer race 3 does not rotate during use in a state where the outer race 3 is connected and fixed to a knuckle 8 constituting a suspension system by an outward flange-shaped mounting portion 7 provided on the outer peripheral surface thereof. still,
A structure in which the outer peripheral surface of the outer race 3 is simply a cylindrical surface (without forming the mounting portion 7) and the outer race 3 is internally fitted and fixed in a support hole of the knuckle 8 is conventionally known as shown in FIG. Have been. A double-row outer raceway 9 is provided on the inner peripheral surface of the outer race 3, and the hub 4 is provided on the inner diameter side of the outer race 3.
And the inner ring 5 is rotatably supported concentrically with the outer ring 3.

[0004] Of these, the hub 4 is located near the end of the outer peripheral surface (in the axial direction, the outer side in the width direction of the vehicle when assembled to the vehicle. The same applies throughout the present specification; the left side of each drawing). A flange 10 for supporting a wheel is provided.
Further, an inner raceway 11a corresponding to the first inner raceway described in the claims is formed at an intermediate portion of the outer peripheral surface of the hub 4, and the inner raceway 11a is also formed inside (in the axial direction, the width of the vehicle when assembled to the automobile). The center in the direction. Same throughout the specification. The right side of each drawing.) A small-diameter portion 12 formed near the end, an outer peripheral surface thereof, and another inner race corresponding to the second inner race described in the claims. The inner ring 5 formed with 11b is externally fitted and fixed. A retaining ring 14 is retained in a retaining groove 13 formed all around the outer peripheral surface of a portion of the inner end of the hub 4 protruding inward in the axial direction from the inner end surface of the inner ring 5. The retaining ring 14 suppresses the inner end surface of the inner ring 5 to prevent the inner ring 5 from shifting in the axial direction. A spline hole 15 is provided in the center of the hub 4.

On the other hand, the constant velocity joint 2 includes a drive shaft member 16. The drive shaft member 16 has a spline shaft 17 which can be engaged with the spline hole 15 in the outer half.
And an outer ring 18 for a constant velocity joint in the inner half. Outer engagement grooves 19 are formed at a plurality of circumferential positions on the inner circumferential surface of the outer race 18 for constant velocity joints, respectively, in a direction perpendicular to the circumferential direction. On the inner diameter side of the outer race 18 for such a constant velocity joint, an inner engaging groove is formed at a part of the outer peripheral surface which is aligned with the outer engaging groove 19.
An inner ring for a constant velocity joint, which is formed in a direction perpendicular to the circumferential direction, is provided. Then, a ball (not shown) is placed between each of the inner engagement grooves and each of the outer engagement grooves 19,
Also, while being held by a retainer (not shown), the inner and outer engagement grooves are provided so as to roll freely along the respective engagement grooves. still,
Regarding the shape of each component of the constant velocity joint 2,
This is the same as the case of a well-known zeppa type or bar field type constant velocity joint, and is not related to the gist of the present invention, so that detailed illustration and description are omitted.

[0006] The constant velocity joint 2 as described above and the wheel supporting bearing unit 1 as described above are connected to the spline shaft 17.
Into the spline hole 15 of the hub 4 from the inside to the outside in the axial direction. And the spline shaft 17
A locking groove 20 which is an inner diameter side engaging portion formed at a portion near the front end of the outer peripheral surface, and an outer diameter side engaging portion provided at a portion of the inner peripheral surface of the hub 4 facing the locking groove 20. The spline shaft 17 is prevented from coming out of the hub 4 by bridging the retaining ring 22 with the locking step portion 21 which is a portion. In this state, the hub 4 and the drive shaft member 16 are
The elastic ring 23 is elastically compressed between the outer ring 18 for a constant velocity joint and the hub 4 and the drive shaft member 16 to prevent axial displacement.

Further, when assembled to the suspension system of the automobile, a male spline, which is also provided in the outer half of the drive shaft (not shown), is provided in a second spline hole provided in the center of the inner ring for the constant velocity joint (not shown). The drive shaft and the inner race for a constant velocity joint are coupled to each other so as to be able to transmit a rotational force by engaging the portions with a spline. Also, the inner end of this drive shaft
It is connected to the output part of a tripod type constant velocity joint, which is another constant velocity joint provided on the differential side. The tripod-type constant velocity joint, the drive shaft, and the constant velocity joint 2 constitute a constant velocity joint unit. Before assembly to the car,
The constant velocity joint unit and the wheel supporting bearing unit 1 are combined to constitute the above-described wheel drive unit.

FIG. 8 shows a second example of the conventional structure described in US Pat. No. 5,674,011.
In the case of the second example of this conventional structure, the outer ring 3 which is not fitted to the knuckle 8 constituting the suspension device and which does not rotate during use in a state of being fixed.
A plurality of rows of outer raceways 9, 9 are provided on the inner peripheral surface of a.
Further, a flange 10 for supporting wheels is provided at a portion near the outer end of the outer peripheral surface of the hub 4a, and inner ring tracks 11a and 11b are provided at a portion near the inner end via a pair of inner rings 5a and 5b.
Each is provided. The inner rings 5a and 5b are supported and fixed to the main body of the hub 4a by caulking portions 24 formed by bending the inner end of the hub 4a outward in the diametrical direction. In addition, each of the outer raceways 9, 9 and each of the inner raceways 1
A plurality of rolling elements 6 are provided between the outer ring 3a and the hub 4a, respectively.
Is rotatably supported.

Further, a spline shaft 17a provided in the outer half of the drive shaft member 16a is inserted into a spline hole 15a provided in the center of the hub 4a. The drive shaft member 16a and the hub 4a are prevented from being separated from each other by a coupling member 26 made of an elastic material which is concavely and convexly engaged with annular concave grooves 25a and 25b formed on the outer peripheral surface of the hub 4a. Is being planned.

As in the conventional structure described above, spline holes 15, 15a provided in the center of hubs 4, 4a and spline shafts 17, 1 provided in the outer halves of drive shaft members 16, 16a.
When the spline 7a is engaged with the spline, it is preferable that vibration and abnormal noise due to rattling are not generated at the spline engagement portion. On the other hand, when the vehicle moves up and down or turns based on the unevenness of the road surface when the car is running, the spline shafts 17 and 17a are caused by a change in the distance between the differential gear and the wheels. An axial load is applied due to a resistance to the sliding movement in the axial direction of the differential constant velocity joint or a centrifugal force. Therefore, if no countermeasures are taken, vibration and abnormal noise may occur due to rattling at the spline engagement portion.

For this reason, in the case of the first example of the conventional structure shown in FIG. 7, the elastic ring 23 is stretched between the hub 4 and the drive shaft member 16 to reduce the play. Preventing. Further, in the case of the second example of the conventional structure shown in FIG. 8, the rattling is prevented by suppressing the hub 4a and the drive shaft member 16a by the coupling member 26.

[0012]

In the case of the conventional structure as described above, in order to prevent the occurrence of vibration and abnormal noise due to rattling, the elastic ring 23 and the coupling member 26, which are relatively expensive parts, are provided. Since it is used, the cost of the entire wheel drive bearing unit increases. In view of such circumstances, the present invention has been made to realize a wheel drive bearing unit that can be manufactured at low cost without using expensive parts.

[0013]

A wheel drive bearing unit according to the present invention comprises an outer ring, a hub, a plurality of rolling elements, and a drive unit, similarly to the above-described conventionally known wheel drive bearing unit. A shaft member. The outer ring has a double-row outer ring raceway on the inner peripheral surface and does not rotate during use. Further, the hub has a flange for supporting the wheel at a portion near the outer end of the outer peripheral surface, a first inner raceway directly or at an intermediate portion of the outer peripheral surface via a separate inner ring, and a spline hole at the center. And an inner ring having a second inner ring track formed on the outer peripheral surface is externally fitted and fixed to a portion near the inner end of the outer peripheral surface. A plurality of rolling elements are provided between the outer raceways and the first and second inner raceways so as to be freely rolled. Further, in the drive shaft member, a spline shaft that engages with the spline hole is provided in an outer half portion, and the inner half portion is an outer race for a constant velocity joint that forms a constant velocity joint.

In particular, in the wheel drive bearing unit of the present invention, an inner diameter side engaging portion formed on the outer peripheral surface of the drive shaft member and an outer diameter side engaging portion formed on the inner peripheral surface of the hub are provided. The spline shaft is prevented from falling out of the spline hole by bridging a retaining ring whose diameter is elastically expandable and contractable between the spline shaft and the spline shaft. At the same time, the amount of movement of the drive shaft member and the hub in the axial direction is set to 1.0 mm or less, more preferably 0.8 mm or less.

[0015]

According to the present invention constructed as described above, it is possible to realize a wheel drive bearing unit which does not generate unpleasant vibrations or abnormal noises due to rattling without using particularly expensive parts. That is, since the amount of movement of the drive shaft member and the hub in the axial direction is restricted to 1.0 mm or less and the above-mentioned rattling is reduced, this rattling leads to generation of unpleasant vibration and abnormal noise. Can be prevented. In this regard, the inventor of the present invention varied the amount of movement under the following conditions, and observed the effect of the value (magnitude) of the amount of movement on the occurrence of vibration and abnormal noise. As a result, if this movement amount is regulated to 1.0 mm or less, the occurrence of this vibration or abnormal noise can be suppressed, or even if it occurs, it does not become uncomfortable, and if regulated to 0.8 mm or less,
It was found that the generation of this vibration and abnormal noise could be suppressed.

In the above experiment, the amount of movement was 0.6 mm,
0.8mm, 1.0mm, 1.2mm, and changed to four types, with the joint angle (the intersection angle between the center axis of the outer ring for constant velocity joint and the center axis of the inner ring for constant velocity joint) applied to the constant velocity joint Then, an alternating torque (in which the direction changes alternately) is applied to the drive shaft member, and the vibration generated at that time is touched by hand on the frame supporting the wheel drive bearing unit, and the noise is heard by ear. , Respectively. Conditions other than the above-mentioned movement amount were all the same. First, the joint angle was changed in the range of 4 to 12 degrees in each case.
The rotation speed of the drive shaft member was set at 500 min ^-1 . The torque applied to the drive shaft member is ± 490.
Nm. Further, a circumferential gap between the spline hole and the spline shaft (when one circumferential side of the female spline teeth and one circumferential side of the male spline teeth are brought into contact with each other, the circumference of the two spline teeth is reduced). The size of the gap between the other sides in the direction is 0.02 mm on the pitch circle.
And

As a result of an experiment conducted under such conditions, when the amount of movement was 1.2 mm, an annoying vibration and an unusual noise were generated. Also, this movement amount is 1.0mm
In the case of (1), vibration and unusual noise were generated, but the vibration was neither annoying nor annoying. Furthermore,
When the amount of movement was 0.8 mm and when the amount of movement was 0.6 mm, both vibration and abnormal noise hardly occurred. As is clear from the results of such experiments, if the amount of movement of the drive shaft member and the hub in the axial direction is regulated to 1.0 mm or less, unpleasant vibration and abnormal noise due to rattling can be prevented. it can. Further, if the amount of movement is restricted to 0.8 mm or less, such vibrations and abnormal noises can hardly be generated.

[0018]

1 and 2 show a first embodiment of the present invention corresponding to the first and second aspects of the present invention. still,
The feature of the present invention is that the amount of movement in the axial direction between the hub 4b constituting the wheel supporting bearing unit 1b and the drive shaft member 16b constituting the constant velocity joint 2a is suppressed, without using expensive parts. The object is to prevent generation of unpleasant vibration and abnormal noise during driving. The configuration and operation of the other parts are the same as in the case of the first example of the conventional structure shown in FIG. 7 described above. Therefore, the same parts are denoted by the same reference numerals, and redundant description is omitted or simplified. The following description focuses on the features of the present invention and the portions different from the above-described conventional structure.

In the case of this embodiment, an inner raceway 11a corresponding to the first inner raceway described in the claims is formed on the outer peripheral surface of the intermediate portion of the hub 4b, and formed on a portion near the inner end of the hub 4b. The inner ring 5 having the second inner raceway 11b described in the claims formed on its outer peripheral surface is fitted to the small diameter portion 12a. In order to prevent the inner ring 5 from coming out of the small diameter portion 12a, a caulking portion 24a is formed at the inner end of the hub 4b. That is, after the inner ring 5 is externally fitted to the small-diameter portion 12a, the portion protruding from the inner end surface of the inner ring 5 at the inner end of the hub 4b is plastically deformed radially outward to form the caulked portion 24a. And this caulking part 2
The inner ring 5 is fixed to the hub 4b by sandwiching the inner ring 5 between the step 4a and the step surface 27 present at the end of the small diameter portion 12a.

Further, on the outer peripheral surface of the outer end portion of the spline shaft 17b constituting the outer half of the drive shaft member 16b, an inner diameter side engaging groove 28, which is an inner diameter side engaging portion, is formed over the entire circumference. It is formed over. On the other hand, on the inner peripheral surface of the outer end of the spline hole 15b provided at the center of the hub 4b, the outer diameter side engaging groove 29 which is the outer diameter side engaging portion described in the claims.
Is formed over the entire circumference. The above spline shaft 17
In the state in which the retaining ring b is inserted into the spline hole 15b, the outer diameter half of the retaining ring 22a having its inner diameter half locked in the inner diameter locking groove 28 is in the outer diameter locking groove 29. Get into it. In this state, the retaining ring 22a is given a resilience in the direction of increasing the diameter. As shown in detail in FIG. 2, the outer peripheral edge of the retaining ring 22a is Elastically abuts the inner surface of the However, in this state, at least a half of the inner diameter side of the retaining ring 22a exists in the inner diameter side locking groove 28. Therefore, the spline shaft 17b is connected to the spline hole 15 by the retaining ring 22a.
It is prevented from falling out of b.

The hub 4b and the drive shaft member 16b
When connecting the retaining ring 22a, the retaining ring 22a is attached to the inner diameter side locking groove 28 before the spline shaft 17b is inserted into the spline hole 15b. When inserting the spline shaft 17b into the spline hole 15b, the retaining ring 22a is guided by the guide inclined surface 30 formed on the inner peripheral surface of the inner end portion of the hub 4b while elastically reducing its diameter. It enters the spline hole 15b. Then, the retaining ring 22a is connected to the outer diameter side locking groove 29.
In a state in which the retaining ring 22a is aligned, the diameter of the retaining ring 22a is elastically restored, and as described above, the retaining ring 22a is moved between the outer diameter side locking groove 29 and the inner diameter side locking groove 28. Be passed over. As a result, the hub 4b and the drive shaft member 16b are inseparably coupled.

As described above, the retaining ring 22a is bridged between the outer diameter side and inner diameter side locking grooves 29, 28, and the hub 4b and the drive shaft member 16b are connected to each other. The inner end surface of the caulking portion 24a and the drive shaft member 16
In order to prevent the outer end surface of the outer ring 18 for constant velocity joint provided in the inner half of the b from coming into contact with the outer end surface (for example, to have a gap of about 1.5 mm), the outer diameter side and inner diameter side locking grooves 29 are provided. , 28 are regulated. Therefore, the caulked portion 24a
No vibration or abnormal noise is generated based on the collision between the inner end surface of the inner ring and the outer end surface of the outer race 18 for a constant velocity joint. or,
Each of the male spline teeth formed on the outer peripheral surface of the spline shaft 17b and the female spline teeth formed on the inner peripheral surface of the spline hole 15b is a parallel spline tooth (width in the circumferential direction) that is easy to machine. Are constant in the axial direction). Then, the size of the gap in the circumferential direction between the spline hole 15b and the spline shaft 17b is set to 0 to 0.050 μm on the pitch circle.
m, the rattling of the spline engagement portion between the spline hole 15b and the spline shaft 17b in the circumferential direction is reduced to zero or very little.

Also, by the operation as described above, the retaining ring 2
The width W ₂₉ , W _{28 of} both the outer diameter side and inner diameter side locking grooves 29, 28 so that 2 a can be freely bridged between the outer diameter side locking groove 29 and the inner diameter side locking groove _28. Is the retaining ring 22a
Constituting, it is slightly larger than the diameter D ₂₂ of circular cross section of the wire. Therefore, the retaining ring 22a is axially (in FIGS. 1 and 2) inside the outer diameter side and inner diameter side locking grooves 29 and 28.
(In the left-right direction). However, such displacement based on the difference between each of the widths W ₂₉ and W ₂₈ and the diameter D ₂₂ is to reduce the amount of axial movement between the hub 4 b and the drive shaft member 16 b to 1.0 mm or less. Is regulated.

This point will be described with reference to FIG. FIG. 2 shows a state in which the hub 4b is displaced outward (to the left in FIGS. 1 and 2) with respect to the drive shaft member 16b. In this state, both axial side surfaces of the retaining ring 22a are
The inner end side inner surface of the outer diameter side locking groove 29 and the outer end side inner side surface of the inner diameter side locking groove 28 abut respectively. In this state, a gap 31 having an axial dimension of △ ₃₁ between the axial outer surface of the retaining ring 22a and the inner surface of the outer end of the outer diameter side locking groove 29 is also formed in the axial direction. Gaps 32 each having an axial dimension of △ ₃₂ are formed between the side surface and the inner end surface of the inner end side locking groove 28. When the hub 4b is displaced inward (to the right in FIGS. 1 and 2) with respect to the drive shaft member 16b from the state shown in FIG. 2, the hub 4b is displaced by the gaps 31, 32. Will be displaced by the sum of ( ₃₁ + △ ₃₂ ). In the case of this example, the total amount is, for example, about 0.4 mm and 1.0 mm.
(△ ₃₁ + △ ₃₂ ≦ 1.0 mm). For this reason, in the case of the present example, as long as the engagement between the retaining ring 22a and both the outer diameter side and the inner diameter side locking grooves 29, 28 can be reliably performed,
The width W ₂₉ , W ₂₈ of these locking grooves ₂₉ , ₂₈ is made as close as possible to the diameter D _{22 of the} wire.

In the illustrated example, the outer diameter side locking groove 29 is formed.
Is formed as a conical concave inclined surface 33 inclined by an angle α with respect to an imaginary plane orthogonal to the center axis of the hub 4b. The inclined surface 33 is provided so that the diameter of the retaining ring 22a can be reduced when the drive shaft member 16b and the hub 4b are separated for disassembly and repair. When the drive shaft member 16b and the hub 4b are separated from each other, the spline shaft 17b constituting the outer half of the drive shaft member 16b is held in a state where the hub 4b is suppressed (displacement in the axial direction is prevented). Is applied to the outer end surface of the first member (for example, about 3500 N). As a result, the diameter of the retaining ring 22a is reduced by a component force applied inward in the radial direction based on the engagement between the inner side surface of the retaining ring 22a and the inclined surface 33, and the retaining ring 22a is connected to the outer diameter side engaging member. It can be pulled out from the stop groove 29. For this reason, the angle α is restricted to about 15 to 20 degrees. In view of the provision of the inclined surface 33, W ₂₉ of the outer diameter side locking groove 29 is set between the outer end side inner side surface of the outer diameter side locking groove 29 and an intermediate portion of the inclined surface 33. The interval between the inner surface of the retaining ring 22a and the portion that comes into contact with the retaining ring 22a.

In the illustrated example, the drive shaft member 16b
A cylindrical surface portion 34 is formed on the outer peripheral surface of the outer end portion of the outer race 18 for a constant velocity joint, which constitutes the inner half of the cylindrical surface portion.
The tone wheel 35 is externally fitted and fixed by interference fit. The tone wheel 35 is formed in a cylindrical shape as a whole by subjecting a magnetic metal plate such as a steel plate to plastic working such as deep drawing by pressing. By forming a large number of slit-shaped through holes 36, 36 elongated in the left-right direction at equal intervals in the circumferential direction, the magnetic properties of the outer peripheral surface are changed alternately and at equal intervals. In a state where the wheel drive bearing unit 1b is assembled to an automobile, a detection unit of a rotation speed sensor (not shown) mounted on a stationary portion such as a suspension device is brought into close proximity to the outer peripheral surface of the tone wheel 35, and the hub 4b The rotation speed of the wheel fixedly supported on the vehicle can be detected. The detection signal of the rotation speed sensor is sent to a controller (not shown) and used for controlling an antilock brake device (ABS) and a traction control device (TCS).

Further, in the illustrated example, the gaps between the inner peripheral surfaces of both ends of the outer race 3 and the outer peripheral surfaces of the intermediate portion of the hub 4b and the inner ends of the inner race 5 are closed by seal rings 37a and 37b. However, the drive shaft member 16b and the hub 4
No seal member is provided between the seal member b. Therefore, the spline engagement portion between the spline hole 15b and the spline shaft 17b and the external space are not particularly blocked.
Further, the seal member cannot provide a damper effect on the relative displacement between the drive shaft member 16b and the hub 4b.

According to the present invention constructed as described above, the elastic ring 2 in the first example of the conventional structure shown in FIG.
3 and the generation of unpleasant vibrations and noises due to backlash without using particularly expensive parts such as the coupling member 26 in the second example of the conventional structure shown in FIG. A wheel drive bearing unit can be realized. That is, in the case of this example, the widths W ₂₉ and W ₂₈ of both the outer diameter side and inner diameter side locking grooves ₂₉ and ₂₈ are made slightly larger than the diameter D _{22 of the} wire constituting the retaining ring 22 a. As a result, the amount of movement of the drive shaft member 16b and the hub 4b in the axial direction is restricted to 1.0 mm or less, and the rattling is reduced. For this reason, it is possible to prevent this rattling from leading to unpleasant vibration or abnormal noise.

Next, FIGS. 3 and 4 show a second embodiment of the present invention corresponding to claims 1 and 3. FIG. In the case of this example, at the outer end of the spline hole 15c provided at the center of the hub 4c constituting the wheel supporting bearing unit 1c,
Female spline portion 40 forming this spline hole 15c
Cylindrical portion 38 having an inner diameter larger than the diameter of the root circle
And the cylindrical surface portion 38 and the female spline portion 40 are formed.
Is formed as a locking step 39. The locking step 39 is also a conical concave surface inclined by an angle α with respect to an imaginary plane orthogonal to the center axis of the hub 4c. The reason why the engaging step 39 is formed as such a conical concave surface is that, in the first example described above, the inner surface of the inner end side of the outer diameter side engaging groove 29 is formed as an inclined surface 33 (see FIG. 2). For the same reason. In the case of this example, the retaining ring 2 locked in the inner diameter side locking groove 28 formed in the outer peripheral surface of the distal end portion of the spline shaft 17b.
2a is engaged with the locking step 39 so that the drive shaft member 16c constituting the constant velocity joint 2b and the hub 4
c is prevented from being separated.

An intermediate portion of the drive shaft member 16c is located at the outer end of the outer race 18a for constant velocity joints and at a portion facing the guide inclined surface 30 formed on the inner peripheral surface of the inner end of the hub 4c. , An inclined step portion 41 is formed. The inclined step portion 41 is inclined at substantially the same angle in the same direction as the guide inclined surface 30. Then, the retaining ring 22a is bridged between the inner diameter side locking groove 28 and the locking step 39 to prevent the drive shaft member 16c from separating from the hub 4c. 41 and the guide inclined surface 30
And the drive shaft member 16c and the hub 4c
So that the amount of movement in the axial direction with
The axial position of the inner diameter side locking groove 28, the locking step 39, the guide inclined surface 30, and the inclined step 41 is regulated.

For example, FIG. 4 shows a state in which the hub 4c is displaced outward (to the left in FIGS. 3 and 4) with respect to the drive shaft member 16c. In this state, the retaining ring 22a
Of the inner diameter side engaging groove 28 and the engaging step portion 39 respectively abut against each other. In this state, a gap 42 having a △ ₄₂ becomes the axial dimension between the inclined guide surface 30 and the inclined step portion 41 is formed. When the hub 4c is displaced most inward (to the right in FIGS. 3 and 4) with respect to the drive shaft member 16c from the state shown in FIG.
Will be displaced by the axial dimension (△ ₄₂ ). In the case of this example, the axial dimension of the gap 42 is set to, for example, 0.6
mm and 1.0 mm or less (△ ₄₂ ≦ 1.0 mm). For this reason, in the case of this example, the guide inclined surface 30 and the inclined surface 30 are not disturbed as long as the retaining ring 22a engaged with the inner diameter side engaging groove 28 and the engaging step portion 39 can be securely engaged. The step 41 is made as close as possible. Incidentally, in this order, the width W ₂₈ of the diametrically inside engagement groove 28, that as close as possible to the diameter D ₂₂ of the wire constituting the stop ring 22a is preferred. Other configurations and operations are the same as those described in the first embodiment.
Since it is the same as the example, the same reference numerals are given to the equivalent parts,
A duplicate description will be omitted.

Next, FIGS. 5 and 6 show a third example of the embodiment of the present invention, which also corresponds to claims 1 and 3. FIG.
In the case of this example, the drive shaft member 16 of the constant velocity joint 2c is used.
By making the outer end face of the outer race 18b for constant velocity joint forming the inner half part of the hub d close to the inner end face of the caulking part 24b formed on the inner end part of the hub 4c, the drive shaft member 16 is formed.
d and the amount of movement of the hub 4c in the axial direction is 1.0 mm
It is as follows.

For example, as shown in FIG. 6, with the hub 4c displaced most outward (to the left in FIGS. 5 and 6) with respect to the drive shaft member 16d, the outer race 1 for a constant velocity joint is displaced.
8b and the inner end surface of the caulked portion 24b.
₄₃ becomes a gap 43 having an axial dimension is formed. When the hub 4c is displaced most inward (to the right in FIGS. 5 and 6) with respect to the drive shaft member 16d from the state shown in FIG. 6, the hub 4c moves in the axial direction of the gap 43. It will be displaced by the dimension (△ ₄₃ ). In the case of this example, the axial dimension of the gap 43 is, for example, about 0.9 mm.
0 mm or less (△ ₄₃ ≦ 1.0 mm). For this reason, in the case of this example, as long as the engagement between the retaining ring 22a locked in the inner diameter side locking groove 28 and the locking step portion 39 can be reliably performed, the inner end surface of the caulking portion 24b is The outer ring 18b for a constant velocity joint is made as close as possible.
For this reason, in the illustrated example, the inner end surface of the caulked portion 24b is processed into a flat surface by face pressing or the like, and the axial position of the inner end surface is strictly regulated. Other configurations and operations are the same as those of the above-described second example, and therefore, the same reference numerals are given to the same parts, and duplicate description will be omitted.

[0034]

Since the present invention is constructed and operates as described above, it is possible to realize a low-cost wheel drive bearing unit which is small and lightweight, and which does not generate unpleasant vibration or abnormal noise. It can contribute to performance improvement and cost reduction.

[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 an enlarged view of a portion A in FIG.

FIG. 3 is a sectional view showing a second example of the embodiment of the present invention.

FIG. 4 is an enlarged view of a portion B in FIG. 3;

FIG. 5 is a sectional view showing a third example of the embodiment of the present invention.

FIG. 6 is an enlarged view of a portion C in FIG. 5;

FIG. 7 is a sectional view showing a first example of a conventional structure.

FIG. 8 is a sectional view showing the second example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c Wheel support bearing unit 2, 2a, 2b, 2c Constant velocity joint 3, 3a Outer ring 4, 4a, 4b, 4c Hub 5, 5a, 5b Inner ring 6 Rolling element 7 Mounting part 8 Knuckle 9 Outer ring Track 10 Flange 11a, 11b Inner ring track 12, 12a Small diameter portion 13 Lock groove 14 Retaining ring 15, 15a, 15b, 15c Spline hole 16, 16a, 16b, 16c, 16d Drive shaft member 17, 17a, 17b Spline shaft 18, 18a, 18b Outer ring for constant velocity joint 19 Outer engaging groove 20 Locking groove 21 Locking step 22, 22a Retaining ring 23 Elastic ring 24, 24a, 24b Caulking part 25a, 25b Annular groove 26 Coupling member 27 Step surface 28 Inner diameter side locking groove 29 Outer diameter side locking groove 30 Guide inclined surface 31 Gap 32 Gap 33 Inclined surface 34 Cylindrical surface portion 35 Tone wheel 36 Through hole 37a, 37b Seal ring 38 Cylindrical surface portion 39 Locking step portion 40 Female spline portion 41 Inclined step portion 42 Gap 43 Gap

Claims (3)

[Claims] 1. A first inner ring raceway having a double row of outer raceways on an inner peripheral surface and not rotating even during use, and a flange for supporting wheels at a portion near the outer end of the outer peripheral surface. Alternatively, a spline hole is provided at the center portion of the outer peripheral surface through a separate inner ring, and a spline hole is provided at the center, and an inner ring having a second inner ring track formed on the outer peripheral surface is externally fitted and fixed to a portion near the inner end of the outer peripheral surface. A plurality of rolling elements respectively provided between the outer raceways and the first and second inner raceways so as to freely roll, and a spline shaft which is spline-engaged with the spline hole. A drive shaft member provided with a half portion and a drive shaft member having an inner half portion as an outer ring for a constant velocity joint constituting a constant velocity joint, wherein an inner diameter formed on an outer peripheral surface of the drive shaft member is provided. Outer diameter formed on the side engaging portion and the inner peripheral surface of the hub By bridging a retaining ring elastically expandable and contractable in diameter between the side engaging portion, the spline shaft is prevented from coming out of the spline hole,
A bearing unit for driving a wheel, wherein the amount of movement of the drive shaft member and the hub in the axial direction is 1.0 mm or less. 2. The inner diameter side engaging portion is an inner diameter side engaging groove formed over the entire outer peripheral surface of the spline shaft, and the outer diameter side engaging portion is formed on the inner peripheral surface of the spline hole. An outer diameter side locking groove. By suppressing the axial displacement amount of the retaining ring in both the inner diameter side and the outer diameter side locking groove, the axial movement amount of the drive shaft member and the hub can be reduced by one. 0.01 mm or less.
A bearing unit for driving a wheel described in the above. 3. An inner diameter side engaging portion is an inner diameter side engaging groove formed over the entire outer peripheral surface of the spline shaft, and an outer diameter side engaging portion is formed at an end inner peripheral surface of the spline hole. By engaging the outer diameter side portion of the retaining ring locked in the inner diameter side locking groove with the locking step portion, the drive shaft member and the hub are prevented from being separated from each other. In this state, the stepped portion formed in the intermediate portion of the drive shaft member and a part of the hub are brought into close proximity to each other, so that the amount of movement in the axial direction between the drive shaft member and the hub is reduced to 1.0 mm or less. The wheel drive bearing unit according to claim 1.