JP2003206948A - Bearing device for driving wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a driving wheel with a fitted portion having a diameter stably enlarged, offering further light and compact construction. <P>SOLUTION: In the bearing device for the driving wheel, a plurality of trains of rolling bearings 2, a hub ring 1 having a wheel mounting flange 4 integrally on the outer periphery at one end, a hardened irregular portion 5 formed on the inner peripheral face and at least one inside rolling face 1a out of inside rolling faces on the plurality of trains of bearings 2, and a synchronous universal joint 3 having a hollow outside joint member 14 are unitized, the hub ring 1 is fitted to the outside joint member 14, its fitted portion 17b with its diameter enlarged by passing therethrough a diameter enlarging tool M having a diameter formed larger than the inner diameter thereof is bitten into the irregular portion 5 of the hub ring 1 to give integrally plastic joint between the hub ring 1 and the outside joint member 14. The inner diameter of an inside joint member 18 of the synchronous universal joint 3 is set to be large enough to pass the diameter enlarging tool M therethrough. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive wheel bearing device for supporting a drive wheel of an automobile or the like, and more particularly to a drive wheel in which a hub wheel, a constant velocity universal joint, and a double row rolling bearing are unitized. Bearing device.

[0002]

2. Description of the Related Art Driving wheels of an automobile such as a rear wheel of an FR vehicle, a front wheel of an FF vehicle, or all wheels of a 4WD vehicle are supported by a suspension device by a bearing device for driving wheels. In recent years, a drive wheel bearing device tends to be unitized with a hub wheel, a constant velocity universal joint, and a bearing portion aiming at weight reduction and compactness.

FIG. 5 is a vertical cross-sectional view showing a drive wheel bearing device, in which a hub wheel 50, a bearing portion 60, and a constant velocity universal joint 70 are unitized. The hub wheel 50 integrally has a wheel mounting flange 51 for mounting a wheel (not shown), and hub bolts 52 for fixing the wheel are planted at equally spaced circumferential positions of the wheel mounting flange 51. There is.

The bearing 60 includes an outer member 61 and an inner member 62.
And a double row rolling element 63, 63, the outer member 61 integrally has a vehicle body mounting flange 64 for attachment to a vehicle body (not shown) on the outer circumference, and a double row outer rolling element on the inner circumference. Surface 61
a and 61a are formed. On the other hand, the inner member 62 has a plurality of rows of inner rolling surfaces 50a and 71a facing the outer rolling surfaces 61a and 61a of the outer member 61.
The one inner raceway surface 50a is integrally formed on the outer circumference of the hub wheel 50, and the other inner raceway surface 71a is integrally formed on the outer circumference of the outer joint member 71 of the constant velocity universal joint 70. The double rows of rolling elements 63, 63 are housed between the outer and inner rolling surfaces 61a, 50a and 61a, 71a, respectively, and the cages 65, 65 are provided.
Is held so that it can roll freely. In this case, the inner member 62 refers to the hub wheel 50 and the outer joint member 71. Seals 66 and 67 are attached to the ends of the bearing 60 to prevent leakage of the lubricating grease sealed inside the bearing and intrusion of rainwater, dust, etc. from the outside.

The constant velocity universal joint 70 includes an outer joint member 71, an inner joint member 73, a cage 74, and a torque transmission ball 75. The outer joint member 71 includes a cup-shaped mouth portion 72 and a shoulder portion 76 that forms a bottom portion of the mouth portion 72.
And a shaft portion 77 extending in the axial direction from the shoulder portion 76,
A curved guide groove 72a extending in the axial direction is formed on the inner circumference of the mouth portion 72.

The shaft portion 7 of the outer joint member 71 formed hollow
7 is fitted in the hub wheel 50, the uneven portion 53 is hardened on the inner peripheral surface of the hub wheel 50, and the cylindrical small-diameter step portion 5 is formed at the end.
4 is formed, and the small-diameter step portion 54 is connected to the small-diameter step portion 7 of the shaft portion 77.
7a and the fitting part 77 of the shaft 77
The diameter of b is increased to make it bite into the concavo-convex portion 53, and the fitting portion 77b is caulked to plastically couple the hub wheel 50 and the outer joint member 71 (see Japanese Patent Laid-Open No. 2001-18605).

On the other hand, in the above-described drive wheel bearing device, the hub wheel 50, the double row rolling bearing 60, and the constant velocity universal joint 7 are provided.
After assembling the outer joint member 71 of 0, that is, after assembling the sub-assemblies, the constant velocity universal joint 70 is assembled. In this assembly of the constant velocity universal joint 70, the inner joint member 73 and the cage 74 are attached to the outer joint member 71. By inserting the guide groove 72a and the guide groove 73a of the joint inner ring 73 so as to face each other, the pocket (not shown) of the cage 74 is opened while tilting the inner joint member 73, and the torque transmission ball 75 is inserted into the pocket of the cage 74. Install it inside.

[0008]

In assembling the conventional drive wheel bearing device, in order to unitize the hub wheel 50 and the bearing portion 60 after assembling the constant velocity universal joint 70, the caulking for expanding the diameter is performed. It was necessary to select a constant velocity universal joint having an inner diameter through which the jig (mandrel) M can pass, that is, a conventional constant velocity universal joint 70 having an increased size of 1 to 2. With this,
This will prevent the device from becoming light and compact. Therefore, conventionally, the procedure of assembling the constant velocity universal joint 70 after such sub-assembly has been adopted (see FIG. 6).
However, the assembling of the constant velocity universal joint 70 is not only poor in workability as compared with the assembling of a single body, but also impact may be applied to the bearing portion 60, and an indentation may be generated on the bearing rolling surface. Therefore, the workability was further reduced.

The present invention has been made in view of the above circumstances, and provides a bearing device for a drive wheel capable of stably expanding the diameter of the fitting portion and further reducing the weight and size. It is an object.

[0010]

[Means for Solving the Problems] In order to achieve the purpose,
The invention according to claim 1 of the present invention has a double row rolling bearing and a wheel mounting flange integrally on one end outer circumference, and forms a hardened concavo-convex portion on an inner peripheral surface to form the double row rolling bearing. At least one of the inner rolling surfaces of the bearing, a hub wheel having a cylindrical small-diameter step extending axially from the inner rolling surface, a cup-shaped mouth portion, and a bottom portion of the mouth portion. And a constant velocity universal joint including a hollow outer joint member having a shaft portion extending in the axial direction from the shoulder portion are unitized, and the hub wheel and the outer joint member are fitted to each other, and The diameter of the hub ring is increased by penetrating the fitting portion with a diameter-expanding jig formed to have a diameter larger than this inner diameter, and is bitten into the uneven portion of the hub wheel to integrally plastically bond the hub wheel and the outer joint member. In the drive wheel bearing device, the inside of the constant velocity universal joint The inner diameter of the hand member said radially enlarged jig is set to a dimension can pass.

As described above, in the drive wheel bearing device in which the hub wheel and the outer joint member are integrally plastically coupled to each other, the inner diameter of the inner joint member of the constant velocity universal joint is set to a dimension through which the expanding jig can pass. This allows the hub ring and the outer joint member to be integrally plastically coupled after assembling the constant velocity universal joint alone, which not only improves workability as compared with conventional products, but also impacts the bearing during assembly. As a result, indentations are not generated on the bearing rolling surface, and the quality can be improved.

According to a second aspect of the present invention, the constant velocity universal joint has an outer joint member in which eight guide grooves extending in the axial direction are formed on a spherical inner peripheral surface, and a spherical outer peripheral surface. An inner joint member in which eight guide grooves extending in the axial direction are formed, and an inner peripheral surface is formed with a fitting portion for tooth-fitting with the shaft portion; the guide groove of the outer joint member; Eight torque transmission balls respectively arranged on eight ball tracks formed in cooperation with the guide groove of the joint member and a cage for holding the torque transmission balls are provided. Open in a wedge shape toward the inner joint member, and a length (PC) of a line connecting the axial width (W) of the inner joint member and the center of the guide groove of the inner joint member and the center of the torque transmission ball.
The ratio Rw (= W / PCR) with R) is 0.69 ≦ Rw ≦
We provide a configuration that is 0.90.

As described above, by finding the reference indicating the optimum range of the axial width (W) of the inner joint member, the assembling workability of the apparatus is improved and the constant velocity universal joint is made light and compact. be able to.

According to a third aspect of the present invention, the constant velocity universal joint has an outer joint member in which eight guide grooves extending in the axial direction are formed on a spherical inner peripheral surface, and a spherical outer peripheral surface. An inner joint member in which eight guide grooves extending in the axial direction are formed, and an inner peripheral surface is formed with a fitting portion for tooth-fitting with the shaft portion; the guide groove of the outer joint member; Eight torque transmission balls respectively arranged on eight ball tracks formed in cooperation with the guide groove of the joint member and a cage for holding the torque transmission balls are provided. A straight portion having a linear groove bottom is provided in each of the guide grooves of the outer joint member and the inner joint member, and the axial width (W) of the inner joint member and the inner side are provided. The center of the guide groove of the joint member and the torque transmission bow Line segment length connecting the centers of (PC
The ratio Rw (= W / PCR) with R) is 0.80 ≦ Rw ≦
We provide a configuration that is 0.93.

As described above, even in the undercut-free structure having a large maximum allowable working angle, similarly to the above-described constant velocity universal joint, a standard indicating the optimum range of the axial width (W) of the inner joint member has been found to reduce the weight and weight. Compactness can be achieved.

Preferably, the ratio r1 (= PCD / Db) of the pitch circle diameter (PCD) and the diameter (Db) of the torque transmitting balls is 3.3≤r as in the invention of claim 4.
By setting 1 ≦ 5.0, the strength of the outer joint member, the load capacity and the durability of the constant velocity universal joint are ensured to be equal to or higher than those of the conventional constant velocity universal joint without increasing the size of the joint. be able to.

Preferably, as in the fifth aspect of the present invention, one inner rolling surface of the double row rolling bearing is formed directly on the outer peripheral surface of the hub wheel, and the other inner rolling surface is formed. By adopting a so-called fourth generation structure directly formed on the outer peripheral surface of the outer joint member, further weight reduction and compactness can be achieved, and the assembling workability of the device can be improved, resulting in mass productivity. Are better.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing a drive wheel bearing device according to the present invention. This drive wheel bearing device comprises a hub wheel 1, a double row rolling bearing 2, and a preassembled constant velocity universal joint 3 as a unit. In addition, in the following description, in the state where the vehicle is assembled,
The side closer to the outside of the vehicle is called the outboard side (left side in the drawing), and the side closer to the center is called the inboard side (right side in the drawing).

The hub wheel 1 integrally has a wheel mounting flange 4 for mounting a wheel (not shown), and hub bolts 6 for fixing the wheel are planted at equally spaced circumferential positions of the wheel mounting flange 4. I have set up.

The double-row rolling bearing 2 includes an outer member 7, an inner member 8 and double-row rolling elements 9 and 9. The outer member 7 is mounted on the outer periphery of a vehicle body (not shown). It has a mounting flange 7a integrally and has a double row of outer raceways 7b on the inner circumference.
7b is formed. On the other hand, the inner member 8 forms a plurality of rows of inner rolling surfaces 1a and 14a facing the outer rolling surfaces 7b and 7b of the outer member 7 described above. The one inner raceway surface 1a is integrally formed on the outer circumference of the hub wheel 1, and the other inner raceway surface 14a is integrally formed on the outer circumference of the outer joint member 14 of the constant velocity universal joint 3. The double rows of rolling elements 9, 9 are housed between the outer and inner rolling surfaces 7b, 1a and 7b, 14a, respectively, and are rotatably held by cages 10, 11. In this case, the inner member 8 refers to the hub wheel 1 and the outer joint member 14. Seals 12 and 13 are attached to the ends of the double-row rolling bearing 2 to prevent leakage of lubricating grease sealed inside the bearing and invasion of rainwater or dust from the outside.

The constant velocity universal joint 3 includes an outer joint member 14, an inner joint member 18, a torque transmission ball 19, and a cage 2.
It has 0 and. The outer joint member 14 includes a cup-shaped mouth portion 15 and a shoulder portion 16 that forms a bottom portion of the mouth portion 15.
And a shaft portion 17 extending from the shoulder portion 16 in the axial direction.

In the constant velocity universal joint 3, as shown in FIG. 2, the outer joint member 14 has a mouth portion in which eight curved guide grooves 15b are axially formed on a spherical inner peripheral surface 15a. 1
Have 5. The inner joint member 18 has a spherical outer peripheral surface 18
Eight curved guide grooves 18b are formed in a in the axial direction, and an engagement portion 18c having a tooth profile (serration or spline) is formed on the inner peripheral surface. Further, the torque transmitting balls 19 are held by the cage 20, and the guide groove 15b of the outer joint member 14 and the corresponding guide groove 18 of the inner joint member 18 are held.
Eight ball tracks are formed on each of the eight ball tracks formed in cooperation with b. The shaft end portion of the drive shaft 21 is tooth-shaped fitted to the engaging portion 18c of the inner joint member 18.

The center of curvature O of the guide groove 15b of the mouse portion 15
1 is offset from the spherical center of the inner peripheral surface 15a, and the center of curvature O2 of the guide groove 18b of the inner joint member 18 is offset from the spherical center of the outer peripheral surface 18a by an equal distance F in the axial direction. ing. Therefore, the ball track formed by the cooperation of the guide groove 15b and the guide groove 18b has a shape that opens like a wedge in one axial direction.

The spherical center of the outer peripheral surface 20a of the cage 20 and the spherical center O1 of the inner peripheral surface 15a of the mouth portion 15 which serves as a guide surface for the outer peripheral surface 20a are joints including the center O3 of the torque transmitting ball 19. Within the central plane O. Therefore, the offset amount F of the center O1 of the guide groove 15b is
Axial distance between center O1 and joint center plane O, guide groove 1
The offset amount F of the center O2 of 8b is the axial distance between the center O2 and the joint center plane O, and both are equal. When the outer joint member 14 and the inner joint member 18 are angularly displaced,
The torque transmission balls 19 guided by the cage 20 are always maintained in the bisector of any operating angle, and the constant velocity of the constant velocity universal joint 3 is ensured.

First, as shown in FIG. 3, when the number of ball tracks and the number of torque transmission balls 19 are eight, the circumferential width L of the outer peripheral surface 18a of the inner joint member 18 is set.
Is relatively smaller than the conventional 6-ball. Furthermore, the minimum value of the circumferential width L of the outer peripheral surface 18a is related to the axial width W of the inner joint member 18, and the larger this W is, the smaller the minimum value of L is. On the other hand, when the inner joint member 18 is preformed by forging, if the minimum value of the circumferential width L of the outer peripheral surface 18a is too small, the material cannot flow sufficiently in the forming die, and thus the guide groove 18b and the outer periphery are not formed. The surface 18a is not accurately finished, and the life of the mold is shortened. Experiments by the applicant have confirmed that there is a minimum value δ of the circumferential width L of the outer peripheral surface 18a that can provide good molding accuracy and die life. Therefore, the axial width W of the inner joint member 18
Must be equal to or smaller than the dimension that can secure this minimum value δ.

That is, from the geometrical relationship, the circumferential width L of the outer peripheral surface 18a is obtained from the coordinates of the boundary portion (shoulder portion) between the outer peripheral surface 18a of the inner joint member 18 and the guide groove 18b, and L is obtained at both ends. The axial width W1 that satisfies the condition of δ is obtained. For the above reason, in order to improve the forgeability of the inner joint member 18, the axial width W needs to satisfy the condition of W ≦ W1. On the other hand, in determining the axial width W of the inner joint member 18, it is necessary to consider the axial relative movement of the torque transmission ball 19 with respect to the guide groove 18b during angular displacement. That is, the axial width W of the inner joint member 18 is W ≦ W
Although it is desirable to make it as small as possible within the range that satisfies 1,
If the axial width W is made too small, the contact ellipse generated in the guide groove 18b due to the contact of the torque transmission balls 19 at the time of angular displacement rides on the guide groove 18b, and the stress is locally concentrated. There is a possibility that uneven wear or chipping of the shoulder of the groove 18b may occur. Therefore, in order to secure the strength and durability of the inner joint member 18, even if the joint has the maximum operating angle, the contact ellipse has the guide groove 18b.
The limit value W0 of the axial width W that does not ride
The axial width W is set so as to satisfy the condition of 0.

Thus, the optimum range of the axial width W of the inner joint member 18 is W0≤W≤W1. Here, the maximum operating angle is set to 47 °, W0 and W1 are obtained for various sizes, and the ratio Rw (of the length PCR of the line segment connecting the center of the guide groove 18b and the center of the torque transmission ball 19 is Rw ( = W / PCR)
I asked. As a result, the condition of 0.69 ≦ W ≦ 0.90 was obtained, and it was found that this is a reference indicating the optimum range of the axial width W of the inner joint member 18.

From the viewpoint of achieving a higher angle,
In a so-called undercut-free structure in which each guide groove 15b, 18b is provided with a straight portion having a linear groove bottom, the maximum operating angle is set to 50 °, and the result obtained by the same criteria as described above is 0. It has been found that the condition of 80 ≦ W ≦ 0.93 is obtained, which serves as a reference indicating the optimum range of the axial width W of the inner joint member 18.

In the above structure, the torque transmission ball 1
The ratio r1 of the pitch circle diameter PCD of 9 and the diameter Db (= PCD
/ Db) can be a value within the range of 3.3 ≦ r1 ≦ 5.0. The reason for 3.3 ≦ r1 ≦ 5.0 is that the strength of the outer joint member 14 and the like, the load capacity of the constant velocity universal joint 3,
This is to ensure durability equal to or higher than that of the conventional 6 balls. That is, in the constant velocity universal joint 3, it is difficult to make the outer diameters the same and to largely change the pitch circle diameter PCD of the torque transmission balls 19 within a limited space. Therefore, r1 depends on the diameter Db of the torque transmission ball 19. If r1 <3.3, the wall thickness of other parts such as the outer joint member 14 and the inner joint member 18 becomes thin, and there is a concern in terms of strength. Conversely, r1> 5.
When it is 0, the load capacity becomes small, which is not preferable. Therefore, by setting 3.3 ≦ r1 ≦ 5.0, the strength of the outer joint member 14 and the like and the load capacity of the constant velocity universal joint can be secured to be equal to or higher than those of the conventional case.

Constant velocity universal joint 3 of the embodiment according to the present invention
The number of torque transmission balls 19 is eight, and the load ratio per torque transmission ball in the total load capacity of the joint is smaller than that of the conventional six constant velocity universal joints. In the joint, the size Db of the torque transmission ball 19 can be reduced, and the minimum wall thickness of the outer joint member 14 and the inner joint member 18 can be secured to the same level as in the conventional case. That is, the outer diameter of the constant velocity universal joint 3 can be made equal to that of the conventional one, and the inner diameter of the inner joint member 18 can be increased.

Next, the constant velocity universal joint 3 and the hub wheel 1 described above.
And a method of assembling the double row rolling bearing 2 by plastic coupling,
This will be described with reference to FIG. First, the hub wheel 1 is placed on the pedestal B, the cylindrical small-diameter step portion 1b formed at the end portion of the hub wheel 1 is brought into abutment with the shoulder portion 16 of the outer joint member 14, and the shaft portion 17 is set to the hub. It fits inside the wheel 1. The mandrel M is lowered from above to pass through the inner diameter of the inner joint member 18 of the constant velocity universal joint 3, and is further lowered until the large diameter portion M1 of the mandrel M penetrates the fitting portion 17b to move the fitting portion 17b. Expand the diameter. Due to this diameter expansion, the fitting portion 17b is bitten into the uneven portion 5 formed by hardening the inner peripheral surface of the hub wheel 1, and the hub wheel 1 and the outer joint member 14 are plastically coupled. Here, the upper end of the mandrel M may be fixed, the pedestal B may be raised by a predetermined stall, and the large diameter portion M1 may be passed through the fitting portion 17b.

Here, in the embodiment according to the present invention, the constant velocity universal joint 3 uses a small diameter torque transmission ball 19,
Since the conventional joint has been changed from 6 balls to 8 balls to secure a load capacity equal to or higher than that of the conventional joint, and the outer diameter of the outer joint member 14 and the inner joint member 18 are reduced while the outer diameter of the joint is made equal, The inner diameter φd of the inner joint member 18 could be formed larger than the outer diameter φD of the large diameter portion M1 of the mandrel M. Therefore, after assembling the constant velocity universal joint 3, the hub wheel 1, the double row rolling bearing 2, and the outer joint member 14 are assembled.
Not only can workability be improved as compared with conventional products, but also the bearing part will not be impacted during assembly and dents will not occur on the bearing rolling surface, which will improve the quality. It is possible to improve.

As described above, the so-called fourth embodiment of the present invention, that is, one of the inner races of the double-row rolling bearing is formed as the hub wheel and the other is formed as the outer joint member.
Although the generation structure has been described, the present invention is not limited to these embodiments at all, and is merely an example, within the scope not departing from the gist of the present invention.
It is needless to say that the present invention can be implemented in various forms, and the scope of the present invention is shown by the description of the claims, and further, the equivalent meanings described in the claims and all the scopes within the scope are provided. Including changes. For example, one of the inner rolling surfaces of a double-row rolling bearing is formed as a hub ring and the other inner rolling surface is formed as a separate inner ring, and this inner ring is formed as a small-diameter step portion of the hub ring. It may be a press-fitted so-called third generation structure.

[0034]

As described above in detail, the drive wheel bearing device according to the present invention is an inner joint of a constant velocity universal joint in a drive wheel bearing device in which a hub wheel and an outer joint member are integrally plastically coupled. By setting the inner diameter of the member to a size that allows the expansion jig to pass, the hub wheel and the outer joint member can be integrally plastically joined after assembling the constant velocity universal joint. Not only is it improved, but the impact is not applied to the bearing portion at the time of assembly, and the indentation is not generated on the bearing rolling surface, so that the quality can be improved.

Further, by using a small diameter torque transmitting ball for the constant velocity universal joint, and changing from 6 balls of the conventional joint to 8 balls, and finding the standard indicating the optimum range of each part, it is equal to or more than the conventional one. Secures the load capacity of the
Compactness can be achieved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a drive wheel bearing device according to the present invention.

FIG. 2 is a vertical sectional view showing a constant velocity universal joint in a drive wheel bearing device according to the present invention.

FIG. 3A is a front view of an inner joint member of the constant velocity universal joint according to the present invention. (B) is a vertical cross-sectional view of (a).

FIG. 4 is a process drawing showing the method of assembling the drive wheel bearing device according to the present invention.

FIG. 5 is a vertical sectional view showing a conventional drive wheel bearing device.

FIG. 6 is a process diagram showing a method of assembling a conventional drive wheel bearing device.

[Explanation of symbols]

1 --- Hub wheels 1a, 14a --- Inner rolling surface 1b, 17a --- Small diameter step 2 ...・ ・ ・ ・ ・ Double row rolling bearings 3 ・ ・ ・ Constant velocity universal joint 4 ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange 5 ・ ・ ・ ・ ・ ・・ ・ Concave / convex part ・ ・ ・ ・ ・ ・ ・ Hub bolt 7 ・ ・ ・ ・ Outer member 7a ・ ・Vehicle body mounting flange 7b ..... Outer rolling surface 8 ..... Inner member 9 ..... 10, 11 ... Retainer 12, 13 ... Seal 14 ... Outer joint member 15 ... ..Mouse portions 15a, 20b ........ Inner peripheral surfaces 15b, 18b ..... Groove 16: Shoulder 17: Shaft 17b: Fitting 18: ...... Inner joint members 18a, 20a ...... Outer peripheral surface 18c ...... Engagement part 19 ...... Torque transmission ball 20・ ・ ・ ・ ・ ・ ・ ・ Cage 21 ・ ・ ・ ・ ・ ・ Drive shaft 50 ・ ・ ・ ・ ・ ・ ・ Hub wheels 50a, 71a ・ ・ Inward rotation Running surface 51 ... Wheel mounting flange 52 ... Hub bolt 53 ... Uneven portions 54, 77a ... ··· Small diameter stepped portion ································· Double-row rolling bearings 61 ······ Outer rolling surface 62 ... Member 63: Rolling element 64: Car body mounting flange 65: Retainer 66, 67 ...・ ・ ・ Seal 70 ・ ・ ・ ・ ・ ・ Constant velocity universal joint 71 ・ ・ ・ Outer joint member 72 ・ ・ ・ ・ ・ ・ ・ Mouse Parts 72a, 73a ... Guide groove 73 ... Inner joint member 74 ... Cage 75 ... ..Torque transmission ball 76 ........ Shoulder 77 .................. Shaft 77b ........ Mating part B ..・ ・ ・ ・ ・ Cradle d ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner diameter of inner joint D ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer diameter of large diameter Db・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Diameter M of torque transmission ball・ ・ ・ Mandrel M1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Large-diameter part O ・ ・ ・ ・ ・ ・ ・ ・ ・ Center surface of joint O1 ・ ・ ・ ・ ・ ・ ・ ・ ・ Mouse Center of curvature O2 of the guide groove of the inner portion of the guide groove of the inner joint member O3・ ・ ・ ・ ・ ・ Pitch circle diameter PCR of torque transmission ball ・ ・ ・ ・ ・ ・ ・ ・ Line segment Rw connecting the center of torque transmission ball and the center of the guide groove of the inner joint member・ ・ ・ ・ ・ Ratio of axial width of inner joint member and PCR r1 ・ ・ ・ ・ ・ ・ Ratio of PCD and Db W ・ ・ ・ ・ ・ ・ ・ ・Axial width W0 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Minimum axial width of the inner joint member W1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Maximum axial width δ of the inner joint member ・ ・..... ... minimum value of the circumferential width of the inner joint member

Claims (5)

[Claims] 1. A double-row rolling bearing and a wheel mounting flange are integrally formed on one end outer circumference, and a hardened concavo-convex portion is formed on an inner peripheral surface of the double-row rolling bearing. At least one of the inner raceways, a hub wheel having a cylindrical small-diameter step extending axially from the inner raceway, a cup-shaped mouth portion and a shoulder portion forming the bottom portion of the mouth portion, A constant velocity universal joint including a hollow outer joint member having a shaft portion extending in the axial direction from the shoulder portion is unitized, and the hub wheel and the outer joint member are fitted to each other, In a bearing device for a drive wheel, the diameter of which is increased by penetrating a diameter-expanding jig formed to have a large diameter so that the hub wheel and the outer joint member are integrally plastically coupled to each other by biting into the uneven portion of the hub wheel. The inner diameter of the inner joint member of the constant velocity universal joint A bearing device for a drive wheel, characterized in that the diameter jig is set to pass through. 2. An outer joint member, wherein the constant velocity universal joint has eight guide grooves axially extending on an inner peripheral surface of a spherical surface,
An inner joint member having eight guide grooves extending in the axial direction on the spherical outer peripheral surface, and a fitting portion on the inner peripheral surface for tooth-fitting with the shaft portion; and a guide groove for the outer joint member. Eight torque transmission balls respectively arranged on the eight ball tracks formed in cooperation with the guide groove of the inner joint member facing each other, and a cage for holding the torque transmission balls,
The ball track opens in a wedge shape toward one side in the axial direction, and a line segment connecting the axial width (W) of the inner joint member, the center of the guide groove of the inner joint member, and the center of the torque transmission ball. Ratio to length (PCR) Rw (= W / PC
The driving wheel bearing device according to claim 1, wherein R) is 0.69 ≦ Rw ≦ 0.90. 3. An outer joint member, wherein the constant velocity universal joint has eight guide grooves extending in the axial direction on a spherical inner peripheral surface,
An inner joint member having eight guide grooves extending in the axial direction on the spherical outer peripheral surface, and a fitting portion on the inner peripheral surface for tooth-fitting with the shaft portion; and a guide groove for the outer joint member. Eight torque transmission balls respectively arranged on the eight ball tracks formed in cooperation with the guide groove of the inner joint member facing each other, and a cage for holding the torque transmission balls,
The ball track opens in one of the axial directions in a wedge shape, and each guide groove of the outer joint member and the inner joint member is provided with a straight portion having a linear groove bottom. The ratio Rw (= W / PC) of the width (W) and the length (PCR) of a line segment connecting the center of the guide groove of the inner joint member and the center of the torque transmission ball.
The drive wheel bearing device according to claim 1, wherein R) is 0.80 ≦ Rw ≦ 0.93. 4. A pitch circle diameter of the torque transmission balls (PC
4. The drive wheel bearing device according to claim 1, wherein a ratio r1 (= PCD / Db) between D) and the diameter (Db) is 3.3 ≦ r1 ≦ 5.0. 5. The inner rolling surface of one of the double row rolling bearings is formed directly on the outer peripheral surface of the hub wheel, and the inner rolling surface of the other is formed directly on the outer peripheral surface of the outer joint member. Item 5. A bearing device for a drive wheel according to any one of items 1 to 4.