JPH11303882A - Constant speed joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure which can transmit sufficient torque while reducing the diameter, and can ensure sufficient durability. SOLUTION: 10 balls 4, 4 are in four pockets 10d, 10e formed in a cage 9c, two or three balls being allocated each of the pockets, and three balls 4, 4 to be held in the pockets 10e, 10e being finally set. With this arrangement, the length L30 of pillars 30, 30 between the adjacent pockets 10d, 10e can be ensured so as to ensure sufficient durability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The constant velocity joint according to the present invention is incorporated, for example, integrally with a rolling bearing unit for supporting a driving wheel on an independent suspension to transmit driving force from a transmission to the driving wheel. Use.

[0002]

2. Description of the Related Art A constant velocity joint is provided between a transmission of an automobile and a driving wheel supported by an independent suspension to control a relative displacement between a differential gear and the driving wheel and a steering angle given to the wheel. Instead, the driving force of the engine can be transmitted to the driving wheels at the same angular velocity over the entire circumference. Conventionally, as a constant velocity joint used for such a portion, for example, Japanese Utility Model Laid-Open No.
No. 5, No. 59-185425, No. 62-12
No. 021 is known.

[0003] Such a conventionally known constant velocity joint 1 transmits rotational force between an inner ring 2 and an outer ring 3 through six balls 4, 4 as shown in FIGS. It is configured to do so. The inner ring 2 is fixed to an outer end (left end in FIG. 9) of one shaft 5 driven to rotate by a transmission. The outer wheel 3 is fixed to the inner end (the right end in FIG. 9) of the other shaft 6 for fixing the drive wheel. An inner engaging groove 7 having an arc-shaped cross section is formed on an outer peripheral surface 2a of the inner race 2.
6 are formed at equal intervals in the circumferential direction, and are formed at right angles to the circumferential direction. Also, the inner peripheral surface 3a of the outer ring 3
At the position facing each of the inner engaging grooves 7, six outer engaging grooves 8, 8 also having an arc-shaped cross section, are formed at right angles to the circumferential direction.

[0004] A retainer 9 having an arc-shaped cross section and being entirely annular is held between the outer peripheral surface 2a of the inner race 2 and the inner peripheral surface 3a of the outer race 3. At six positions in the circumferential direction of the retainer 9, pockets 10, 10 are formed at positions corresponding to the inner and outer engagement grooves 7, 8, and one pocket 10 is formed inside each pocket 10, 10. Each of them holds a total of six balls 4,4. These balls 4, 4
While being held in the pockets 10, 10, they can roll freely along the inner and outer engagement grooves 7, 8.

As shown in FIG. 11, each of the pockets 10, 10 has a rectangular shape which is long in the circumferential direction, and the balls 4, 4 adjacent to each other in the circumferential direction are changed in accordance with a change in the axis intersection angle α described below. Even if the interval changes, the change can be absorbed. That is, the bottom surfaces 7a, 7a of the inner engagement grooves 7, 7
The positional relationship between them, and the positional relationship between the bottom surfaces 8a, 8a of the outer engagement grooves 8, 8 have a relationship like a meridian of a globe as shown by a dashed line in FIG. When the center axis of the inner ring 2 matches the center axis of the outer ring 3 (axis intersection angle α = 180 °), each of the balls 4, 4 is positioned at the equator of the globe shown by the two-dot chain line in FIG. Present near the corresponding position. On the other hand, the center axis of the inner ring 2 does not match the center axis of the outer ring 3 (axis intersection angle α <180 °).
And each of the balls 4 with the rotation of the constant velocity joint 1,
4 reciprocates vertically (alternately in the north and south poles of the globe) in FIG. As a result, the distance between the balls 4, 4 adjacent in the circumferential direction is enlarged or reduced, so that each of the pockets 10, 10 is formed as a rectangle long in the circumferential direction so that the distance can be expanded or reduced.
Note that the bottom surfaces 7a, 7a of the inner engaging grooves 7, 7 and the bottom surfaces 8a, 8a of the outer engaging grooves 8, 8 are not concentric with each other, as will be apparent from the following description. Therefore, the lines corresponding to the meridians are slightly offset from each other in each of the engagement grooves 7 and 8.

Further, as shown in FIG. 9, regardless of the displacement between the one shaft 5 and the other shaft 6, each of the balls 4
At the intersection o between the center line a of the one shaft 5 and the center line b of the other shaft 6, the two lines a,
It is arranged in a bisecting plane c that bisects the angle α formed by b. Therefore, the bottom surfaces 7a, 7 of the inner engagement grooves 7, 7 are provided.
a is located on the center line a on a spherical surface centered on a point d separated by h from the intersection o, and the bottom surfaces 8a, 8a of the outer engagement grooves 8, 8 are located on the center line b. , And is located on a spherical surface centered on a point e which is separated from the intersection o by h. However, the outer peripheral surface 2a of the inner ring 2, the inner peripheral surface 3a of the outer ring 3, and the inner and outer peripheral surfaces of the retainer 9 are respectively located on a spherical surface centered at the intersection point o, and the outer periphery of the inner ring 2 Sliding between the surface 2a and the inner peripheral surface of the cage 9 and sliding between the inner peripheral surface 3a of the outer ring 3 and the outer peripheral surface of the cage 9 are allowed.

In the case of the constant velocity joint 1 constructed as described above, when the inner ring 2 is rotated by the one shaft 5, this rotational motion is transmitted to the outer ring 3 via the six balls 4, 4. Shaft 6 rotates. When the positional relationship between the two shafts 5 and 6 (the axis intersection angle α) changes, the balls 4 and 4 roll along the inner and outer engagement grooves 7 and 8, and the one shaft 5 and the other shaft 6 are allowed to displace.

Although the basic structure and operation of the constant velocity joint are as described above, such a constant velocity joint and a rolling bearing unit for a wheel for rotatably supporting the wheel with respect to a suspension device are provided. Integral combination has been studied in recent years. That is, in order to rotatably support the wheels of the automobile on the suspension device, a rolling bearing unit for a wheel in which an outer ring and an inner ring are rotatably combined via a rolling element is used. If such a rolling bearing unit for a wheel and the above-described constant velocity joint are integrally combined, the rolling bearing unit for a wheel and the constant velocity joint can be configured to be small and lightweight as a whole. As a so-called fourth-generation hub unit, a so-called fourth-generation wheel rolling bearing unit integrally combining such a rolling bearing unit for a wheel and a constant velocity joint is disclosed in Japanese Patent Application Laid-Open No. Hei 7-31775.
No. 4 is known.

FIG. 13 shows a conventional structure described in this publication. In an assembled state to a vehicle, the outer ring 11 which does not rotate while being supported by the suspension device has a first mounting flange 12 for supporting the suspension device on the outer peripheral surface, and a double-row outer ring raceway 13 on the inner peripheral surface. 13 respectively. Inside the outer ring 11, first and second inner ring members 14, 15 are provided.
Are arranged. The first inner ring member 14 has a second mounting flange 17 for supporting the wheel at one end (leftward in FIG. 13) of the outer peripheral surface, and a second mounting flange 17 at the other end (rightward in FIG. 13). The first inner raceway 18 is formed in a cylindrical shape provided for each. On the other hand, the second inner ring member 15 has one end (the left end in FIG. 13) as a cylindrical portion 19 for externally fitting and fixing the first inner ring member 14, and the other end (FIG. 13). (The right end) is the outer race 3A of the constant velocity joint 1a, and the second inner raceway 20 is provided on the outer peripheral surface of the intermediate part. Then, each of the outer raceways 13, 13 and the first and second inner raceways 18,
By providing a plurality of rolling elements 21, 21 respectively with the hub 16, the hub 16 is provided inside the outer race 11.
Is rotatably supported.

[0010] Locking grooves 22 and 23 are formed at positions where the inner peripheral surface of the first inner ring member 14 and the outer peripheral surface of the second inner ring member 15 are aligned with each other, and a retaining ring is provided. The first inner race member 14 is prevented from falling out of the second inner race member 15 by providing the first inner race member 14 in such a manner as to bridge the two engagement grooves 22 and 23. Further, the outer peripheral edge of one end face (left end face in FIG. 13) of the second inner ring member 15 and the stepped portion 2 formed on the inner peripheral face of the first inner ring member 14
The first and second inner ring members 14 and 15 are connected and fixed to each other by welding 26 between the inner ring members 5 and 5.

A substantially cylindrical cover 27a, 27b made of a metal such as a stainless steel plate and an elastomer such as rubber are provided between the openings at both ends of the outer race 11 and the outer peripheral surface of the intermediate portion of the hub 16. Annular seal ring 2 made of elastic material
8a and 28b. These covers 27a, 2
7b and the seal rings 28a and 28b block the portion where the plurality of rolling elements 21 and 21 are installed from the outside, prevent the grease present in this portion from leaking to the outside, and provide rainwater, Prevents foreign matter such as dust from entering. Further, a partition plate portion 29 for closing the inside of the second inner ring member 15 is provided inside the intermediate portion of the second inner ring member 15 so as to secure the rigidity of the second inner ring member 15. The foreign matter that has entered the inside of the second inner ring member 15 from the opening (the left end in FIG. 13) of the second inner ring member 15 is prevented from reaching the constant velocity joint 1a. This constant velocity joint 1a is the same as that shown in FIG.
It has the same configuration as the constant velocity joint 1 shown in FIGS.

When assembling the rolling bearing unit for a wheel configured as described above to a vehicle, the first mounting flange 1
2 supports the outer ring 11 on the suspension device, and the second mounting flange 17 allows the driving wheel to be connected to the first inner ring member 14.
Fixed to. Also, the tip of a drive shaft (not shown), which is rotationally driven by the engine via a transmission,
The spline is engaged with the inside of the inner ring 2 constituting the constant velocity joint 1a. When the automobile is running, the rotation of the inner race 2 is transmitted to the hub 16 including the second inner race member 15 via the plurality of balls 4 to rotate the wheels.

In order to further reduce the size of the fourth-generation rolling bearing unit for wheels as described above, the constant velocity joint 1 must be used.
It is effective to reduce the diameter of the circumscribed circle of the plurality of balls 4 that constitute a. Then, in order to reduce the diameter of the circumscribed circle, the diameter of each of the balls 4, 4 is reduced,
Moreover, it is necessary to increase the number of the balls 4, 4 in order to secure the torque that can be transmitted by the constant velocity joint 1a. Even if the number of balls 4 is increased due to such circumstances, in order to ensure the durability of the cage 9 holding these balls 4, a plurality of balls provided on the cage 9 are required. A pillar portion 30 existing between the pockets 10;
It is necessary to secure a circumferential length of 30 (see FIGS. 10, 11, 15, 17 to 19).

If the length of each of the pillars 30, 30 in the circumferential direction is insufficient, the retainer 9 may be used.
This is because the rigidity of the pockets 10 is insufficient, and there is a possibility that damages such as cracks may occur from the peripheral portions of the pockets 10 and 10 with use over a long period of time. That is, the constant velocity joint 1a
Is operated with a joint angle (an angle at which the positional relationship between the center axis of the inner ring 2 and the center axis of the outer ring 3A deviates from the linear state; the complement of the axis intersection angle α shown in FIG. 9). The balls 4, 4 have bottom surfaces 7 of both inner and outer engagement grooves 7, 8.
a and 8a receive forces as shown by arrows A and A in FIGS. Then, as a resultant force of the forces indicated by arrows A and B, the balls 4 are pressed against the intermediate portion of the inner surface of the rim portion 31 of the retainer 9 as indicated by the arrow B in FIG. As a result, the rim portion 31 has
A moment load is applied around the connecting portion between 0 and 30, and stress is applied to this connecting portion. The stress increases as the circumferential length of the pockets 10 and 10 increases and the length of the pillars 30 and 30 in the circumferential direction decreases. Damage is likely to occur. Therefore, in order to sufficiently ensure the durability of the retainer 9, the length of each of the pockets 10 and 10 in the circumferential direction is reduced, and each of the pillars 30 adjacent in the circumferential direction is reduced.
It is necessary to increase the length of 30 in the circumferential direction.

However, increasing the length of each of the pillars 30, 30 is restricted from the viewpoint of preventing interference with the balls 4, 4. That is, first, each of the pockets 10, 10
The length in the circumferential direction is such that the balls 4, 4 can be displaced in the circumferential direction of the retainer 9 when the constant velocity joint 1a is rotated with a joint angle. Need to be. Secondly, after assembling the constant velocity joint 1a, the inner ring 2, the outer ring 3A and the retainer 9 are combined, and then the balls 4 are inserted into the pockets 10 and 10 of the retainer 9. It must be large enough to accommodate 4.

Considering such points, the ball 4,
Japanese Patent Application Laid-Open No. HEI 9-177781 discloses a structure in which the number of 4 is larger than 6 and the length of each of the column portions 30 is increased.
No. 4 describes a constant velocity joint 1b as shown in FIGS. The constant velocity joint 1b described in this publication transmits the rotational force between the inner ring 2 and the outer ring 3 by eight.
It is configured so as to be performed via the balls 4, 4. In the case of the structure described in this publication,
The pockets 10a and 10a having a large length in the circumferential direction and the pockets 1 having a short length are provided at eight circumferential positions of a.
0b and 10b are arranged at regular intervals (with the same division pitch angle) and alternately. Of these two types of pockets 10a and 10b, the pockets 10b and 10b having shorter lengths are arranged at both ends in the longitudinal direction of each of the pockets 10b and 10b even when the constant velocity joint 1b is used at the maximum joint angle. The inner side surface and the rolling surfaces of the balls 4, 4 held in these pockets 10b, 10b are sized so as not to interfere with each other. On the other hand, the pockets 10a and 10a having long lengths are arranged so that the central axis of the inner ring 2 and the central axis of the outer ring 3 are aligned with each other to accommodate the balls 4 and 4 in the pockets 10a and 10a. Even when the pockets 10a and 10a are tilted beyond the maximum value of the joint angle in the above use state,
The inner surfaces of both ends in the longitudinal direction and these pockets 10a, 1a
The ball 4 has a size that does not interfere with the rolling surfaces of the balls 4 and 4 to be incorporated within 0a.

The above-mentioned Japanese Patent Application Laid-Open No. 9-1 is constructed as described above.
According to the constant velocity joint 1b described in Japanese Patent No. 77814, after the balls 4, 4 are assembled into the pockets 10a, 10a having a long length, the pocket 10 having a short length is used.
By incorporating balls 4 and 4 in b and 10b, balls 4 and 4 can be incorporated in all pockets 10a and 10b. That is, when assembling the balls 4 and 4 into these pockets 10a and 10b, as shown in FIG. 19, the center axis of the inner ring 2 and the center axis of the outer ring 3 are connected to each other by the joint angle in the use state. This is performed in a state where the inclination exceeds the maximum value. When assembling the balls 4 into the long pockets 10a, 10a, the pockets 10a, 10a,
The end of Oa and the ends of the inner engagement grooves 7, 7 formed on the outer peripheral surface of the inner race 2 are aligned with one or more of the balls 4, 4, respectively. Therefore, the balls 4, 4 can be reliably incorporated into each of the pockets 10a, 10a. Then
When the center axis of the inner ring 2 and the center axis of the outer ring 3 are inclined as shown in FIG. 19 to incorporate the balls 4 and 4 into the four pockets 10b and 10b having short lengths, the length is already increased. As shown by broken lines in FIG. 18, the balls 4, 4 incorporated in the long pockets 10a, 10a approach the short pockets 10b, 10b.
It is displaced within each of the pockets 10a, 10a. And
The central portion of each of the short pockets 10b, 10b and the end of the inner engaging groove 7, 7 formed on the outer peripheral surface of the inner race 2 are aligned. Therefore, each of these pockets 10b,
Incorporation of the balls 4, 4 into the 10b can be ensured.

Further, as shown in FIG. 20, in the specification of British Patent No. 1537067, two pockets 10c and 10c are formed at equal intervals in the circumferential direction of the retainer 9b. The structure holding the balls 4 and 4 is described. According to such a structure, the same pocket 1
The pockets 10c and 10c circumferentially adjacent to each other are reduced by the distance between the balls 4 and 4 held in the insides 0c and 10c.
By increasing the length dimension of the pillar portions 30, 30 existing between each other, the durability of the retainer 9b can be ensured.

[0019]

SUMMARY OF THE INVENTION The aforementioned Japanese Patent Laid-Open No. 9-17 / 1997
In the case of the structure described in Japanese Patent No. 7814, each of the pockets 10a and 10b holds one ball 4 and 4, respectively. It is difficult to balance the securing of the length dimension of 30, 30 with a high dimension. For this reason, it is not always possible to realize a constant velocity joint capable of transmitting a sufficiently large torque and having sufficient durability.

Further, in the case of the structure described in the above-mentioned British Patent No. 1537067, when the outer diameter of each ball 4, 4 is reduced in order to reduce the outer diameter of the constant velocity joint, adjacent balls 4 are adjacent to each other. The length dimension of the pillar portions 30, 30 existing between the pockets 10c, 10c becomes larger than necessary. As a result, the life of the retainer 9b becomes too long with respect to the peeling life of the surface portions of the inner and outer locking grooves 7, 8, and the balance is poor from the viewpoint of ensuring the durability of the entire constant velocity joint. It becomes a design. In view of such circumstances, the present invention has been made to realize a constant velocity joint which can be configured to be small and lightweight, can transmit a sufficiently large torque, and has sufficient durability.

[0021]

The constant velocity joint according to the present invention has an inner race and an inner ring similar to the above-mentioned conventional constant velocity joint.
At a plurality of locations on the outer peripheral surface of the inner ring, an inner engaging groove having an arc-shaped cross section formed in a direction perpendicular to the circumferential direction, an outer ring provided around the inner ring, and an inner peripheral surface of the outer ring. An outer engaging groove having an arc-shaped cross section formed in a direction perpendicular to the circumferential direction at a position facing each of the inner engaging grooves, and sandwiched between an outer peripheral surface of the inner ring and an inner peripheral surface of the outer ring. A retainer having a plurality of circumferentially long pockets formed at positions aligned with the inner and outer engagement grooves, and a pair of inner and outer engagement grooves held inside the respective pockets. And a plurality of balls that are free to roll along. Each of these balls is disposed in a bisecting plane perpendicular to a plane including the central axes by bisecting the axis intersection angle between the central axis of the inner ring and the central axis of the outer ring.

In particular, in the constant velocity joint according to the first aspect, at least a part of the plurality of pockets is capable of holding a plurality of balls in a single pocket. The total number of balls is 7 or more (more preferably 8 or more). In the constant velocity joint according to the second aspect, the number of the pockets is an even number, and the number of balls held by each of the pockets is different. Further, in the constant velocity joint according to the third aspect, the number of balls is four, the number of balls is ten, and the number of balls held by the two pockets present on the diametrically opposite side. Are two, and the remaining two pockets hold three balls each.

[0023]

In the case of the constant velocity joint of the present invention configured as described above, since the total number of balls is seven or more, even if a sufficiently large torque can be freely transmitted, the outer diameter is reduced and the size is reduced. And it can be made lightweight. Moreover, the distance between the balls held in the same pocket is narrowed, the length of the column existing between the circumferentially adjacent pockets is increased, and the durability of the cage is secured. Sufficient durability can be obtained for the constant velocity joint as a whole. In particular, if the number of balls held by each pocket is made different as in the constant velocity joints according to the second and third aspects, the ball is finally incorporated into a pocket having a large number of balls to be held. As a result, the ball can be incorporated, and the length of the pocket can be prevented from increasing. As a result, the number of balls incorporated in the constant velocity joint can be increased, and the durability of the cage can be ensured.

[0024]

1 to 4 show a first embodiment of the present invention corresponding to claim 3. FIG. This embodiment shows a structure in which the constant velocity joint of the present invention is incorporated in a fourth generation hub unit. First, the structure of the hub unit will be described. The outer ring 1 is provided on the outer peripheral surface of the outer ring 11 which does not rotate while being supported by the suspension device.
First mounting flange 12 for supporting 1 on suspension
, And a double-row outer raceway 13 is formed on the inner peripheral surface. On the inner diameter side of the outer ring 11, a hub 16 including a first inner ring member 14a and a second inner ring member 15a is provided.
a is arranged concentrically with the outer race 11. This hub 1
First and second inner raceways 18 and 20 are provided on portions of the outer peripheral surface of 6a opposed to the outer raceways 13 and 13, respectively. Of these two inner raceways 18, 20, the first inner raceway 18 is formed directly on the outer peripheral surface of the intermediate portion of the first inner race member 14a. Also, the first inner ring member 14
The second inner ring member 15a is externally fitted to a portion closer to the inner end (closer to the right end in FIG. 1) than the portion where the first inner ring raceway 18 is formed, in the intermediate portion a. The second inner raceway 20 is formed on the outer peripheral surface of the second inner race member 15a. A plurality of rolling elements 21, 21 are provided between each of the outer raceways 13, 13 and the first and second inner raceways 18, 20 so as to be able to roll freely. The hub 16a is rotatably supported inside.

In the case of the illustrated example, as described above, the diameter of the first inner raceway 18 is formed by directly forming the first inner raceway 18 on the outer peripheral surface of the first inner race member 14a. Is smaller than the diameter of the second inner raceway 20 formed on the outer peripheral surface of the second inner race member 15a. Also, as described above, the diameter of the first inner raceway 18 is changed to the second inner raceway 20.
Is smaller than the diameter of the first inner raceway 18, the diameter of the outer raceway 13 on the outer side (referred to as the outer side in the width direction when assembled to the vehicle and on the left side in FIG. 1) is The diameter is smaller than the diameter of the outer raceway 13 on the inner side (referred to as the center side in the width direction when assembled to an automobile, and on the right side in FIG. 1). Further, the outer diameter of the outer half of the outer race 11 (the half that is the widthwise outside when assembled to the vehicle and the left half in FIG. 1) on which the outer race 13 is formed is determined by the inner outer race. The outer ring 1 which is a portion where the track 13 is formed.
1 is smaller than the outer diameter of the inner half part (the half part on the center side in the width direction when assembled to the vehicle, the right half part in FIG. 1). In the illustrated example, the diameters of the first inner raceway 18 and the outer outer raceway 13 are reduced in this manner, so that the rolls provided between the first inner raceway 18 and the outer outer raceway 13 are provided. The number of moving bodies 21 and 21 is
Rollers 21, 2 provided between the inner race 0 and the inner outer raceway 13
The number is less than one.

On the outer peripheral surface of the outer end of the first inner ring member 14a, a second mounting flange 17 for supporting and fixing a wheel to the first inner ring member 14a is provided. A plurality of studs 32 for connecting the wheel to the second mounting flange 17.
The base end is fixed. In the case of the illustrated example, the pitch circle diameter of the plurality of studs 32 is equal to the outer ring 1 as described above.
The outer diameter of the outer half of the outer ring 11 is made smaller than the outer diameter of the inner half (to the extent that the head 33 of each stud 32 does not interfere with the outer peripheral surface of the outer end of the outer ring 11). ing. Note that, of the outer peripheral surface of the first inner ring member 14a,
The diameter of the portion existing inward in the axial direction from the portion where the first inner raceway 18 is formed is smaller than the diameter of the inscribed circle of the rolling elements 21 corresponding to the first inner raceway 18. ing. The reason for this is that at the time of assembling the rolling bearing unit for a wheel, a plurality of rolling elements 21 and 21 are assembled on the inner diameter side of the outer raceway 13 formed on the inner peripheral surface of the outer race 11 and the inner circumference of the outer race 11 at the outer end. Seal ring 3 on the surface
This is because the first inner ring member 14a can be freely inserted into the inner diameter side of the outer ring 11 with the inner ring 4 fixed. or,
On the outer peripheral surface of the intermediate portion of the first inner ring member 14a, between the first inner ring raceway 18 and the portion where the second inner ring member 15a is externally fitted, a groove-shaped meat is formed over the entire circumference. Stealing part 35
To reduce the weight of the first inner ring member 14a.

Further, the second inner race member 15a externally fitted to the first inner race member 14a is prevented from shifting toward the inner end side in the axial direction, so that the outer raceways 13, 13 and the first and second races 13 are prevented from moving. The outer circumference of the first inner race member 14a is provided between the two inner raceways 18 and 20 so as to be able to freely roll, each of which is provided with a plurality of rolling elements 21 and 21 so that the preload applied to the rolling elements 21 and 21 is maintained at an appropriate value. A retaining ring 37 is locked in a locking groove 36 formed over the entire circumference near the in-plane end. The retaining ring 37 is composed of a pair of retaining ring elements each having a semicircular arc shape. Such a retaining ring 37 presses the second inner ring member 15a axially outward with respect to the first inner ring member 14a in order to apply an appropriate preload to the rolling elements 21 and 21. The inner peripheral edge is engaged with the locking groove 36.
Even in a state where the force pressing the second inner ring member 15a outward in the axial direction is released, the retaining ring 37 is used as the retaining ring 37 so as to keep the appropriate preload applied to the rolling elements 21 and 21.
Select and use those with appropriate thickness dimensions. That is, a plurality of types of the retaining ring 37 having slightly different thickness dimensions are prepared, and an appropriate thickness is set in relation to the dimensions of the components of the rolling bearing unit, such as the groove width of the locking concave groove 36. A retaining ring 37 having dimensions is selected and engaged with the locking groove 36. Therefore, if the retaining ring 37 is locked in the locking groove 36, the second inner ring member 15a is prevented from shifting toward the inner end in the axial direction even when the pressing force is released. Thus, it is possible to maintain the rolling elements 21 and 21 with an appropriate preload applied thereto.

Further, in order to prevent a pair of retaining ring elements constituting the retaining ring 37 from being displaced radially outward and to prevent the retaining ring 37 from accidentally falling out of the locking groove 36,
A part of the spacer 38 is arranged around the retaining ring 37. The spacer 38 is a constant velocity joint 1 constituted by an outer ring 3B provided at an inner end portion of the first inner ring member 14a.
The outer end of the boot 39 for preventing a foreign substance such as rainwater and dust from entering the inside of c is fitted and supported. still,
The boot 39 is integrally formed of an elastic material such as rubber or synthetic resin, and has an intermediate portion formed in a bellows shape and both ends formed in a cylindrical shape. The outer end of such a boot 39 is externally fitted to a metal spacer 38 which is externally fitted and fixed to the inner end of the first inner ring member 14a by interference fit, and the outer periphery of the spacer 38 is formed by a restraining band 40. It is held down on the surface. The inner peripheral surface of the outer end of the boot 39 is engaged with the engaging groove 41 formed on the outer peripheral surface of the spacer 38 over the entire circumference.

At the outer edge of the spacer 38, the boot 39
A portion protruding outward in the axial direction is formed in a crank shape in cross section to constitute a holding portion 42 over the entire circumference. In order to form the holding portion 42, the spacer 38 is provided with a small-diameter cylindrical portion 43 fitted and fixed to the inner end of the first inner ring member 14a.
And a large-diameter cylindrical portion 45 bent radially outward from the outer edge of the small-diameter cylindrical portion 43 and a large-diameter cylindrical portion 45 bent axially outward from the outer peripheral edge of the circular ring portion 44.
Then, the outer surface of the circular ring portion 44 is fixed to the retaining ring 3.
7 and the inner peripheral surface of the large-diameter cylindrical portion 45 on the outer peripheral surface of the retaining ring 37.
They are in contact or close proximity. Further, a seal ring 34 is provided between the outer peripheral surface of the outer end of the outer race 11 and the outer peripheral surface of the intermediate portion of the first inner race member 14a, and the inner peripheral surface of the inner race of the outer race 11 is connected to the second inner race member. A combination seal ring 46 is provided between the inner peripheral portion 15a and the outer peripheral surface of the inner peripheral portion 15a to close the openings at both ends of the space 47 in which the plurality of rolling elements 21 are installed.

Further, a portion of the inner end of the first inner ring member 14a where the second inner ring member 15a and the outer end of the boot 39 are fitted is an outer ring 3B constituting the constant velocity joint 1c. And On the inner peripheral surface of the outer ring 3B, ten outer engaging grooves 8, 8 each having an arc-shaped cross section when cut along a virtual plane orthogonal to the center axis of the outer ring 3B, Each is formed in a direction perpendicular to the circumferential direction (the left-right direction in FIG. 1 and the front-back direction in FIG. 2).
An inner ring 2A for constituting the constant velocity joint 1c together with the outer ring 3B is disposed inside the outer ring 3B. On the outer peripheral surface of the inner ring 2A, ten inner engaging grooves 7, 7 are respectively formed in a direction perpendicular to the circumferential direction. Then, between each of the inner engagement grooves 7, 7 and each of the outer engagement grooves 8, 8, a total of ten balls 4, 4, one for each of the engagement grooves 7, 8, are placed. It is provided so as to roll freely while being held in the pockets 10d and 10e of the holder 9c. Further, a spline hole 48 is formed in the center of the inner ring 2A in the axial direction. In an assembled state to the automobile, an end of a drive shaft (not shown) is spline-engaged with the spline hole 48, and the first inner ring member 1 is connected via the inner ring 2 </ b> A and the ten balls 4, 4.
4a is freely rotatable.

In particular, in the case of the constant velocity joint 1c of the present invention incorporated in the hub unit as described above, the ten balls 4, 4 are incorporated into the pockets 10d, 10e of the retainer 9c. And the pillars 30, 3 between the circumferentially adjacent pockets 10d, 10e.
In order to secure a length in the circumferential direction of 0, the following configuration is adopted. First, the number of the pockets 10d and 10e is four in total. The number of the balls 4 and 4 held in the four pockets 10d and 10e is ten in total. And the four pockets 10
The number of balls 4, 4 held by the two pockets 10d, 10d present on the opposite side in the diametrical direction (vertical direction in FIG. 2) is two each, that is, four in total. On the other hand, the remaining two pockets 10e, 10e
The number of the balls 4 and 4 held by each is three each, that is, a total of six balls.

As described above, the four pockets 10d,
The number of balls 4, 4 held in 10e is alternately changed from 2 to 3 to 2 to 3 in the circumferential direction. Thus, each pocket 10d, 1
The procedure for assembling the balls 4 and 4 into the two pockets 10d and 10d on the diametrically opposite side is as follows.
The operation of assembling a total of four balls 4 and 4 is performed first, and the operation of assembling a total of six balls 4 and 4 into three pockets 10e and 10e is performed later. By regulating the procedure for assembling in this way, the pockets 10e for incorporating three balls 4, 4 respectively,
The length L10e in the circumferential direction of _10e can be kept as small as possible. In other words, the length (L _10e / 3) of each of the pockets 10e and 10e into which three balls 4 and 4 are respectively incorporated is determined by the length of each of the pockets 10d and 10d into which two balls 4 and 4 are respectively incorporated. Smaller than the length of each ball (L _10d / 2)
Pocket 10d adjacent in the circumferential direction so as to ensure a length L ₃₀ over the circumferential direction of the pillar portion 30, 30 that exists between the 10e together. The pitch of the engagement grooves 7 and 8 in the circumferential direction is the length L of the pockets 10d and 10e.
_10d and L _10e are restricted. In the illustrated example, the pitch in the circumferential direction is unequal.

The reason why the length L30 of each of the pillars 30, ₃₀ can be ensured by regulating the assembly procedure of each of the balls 4, 4 as described above will be described with reference to FIG. In a state where the balls 4 and 4 are newly installed while giving a joint angle to the constant velocity joint 1c, as is clear from the above description regarding FIGS. 12 and 18 to 19, the directions in which the already installed balls 4 and 4 approach each other. In the circumferential direction. Further, the joint angle given to the constant velocity joint 1c when the balls 4, 4 are assembled is much larger than the joint angle given to the constant velocity joint 1c during use (in a state of being installed in an automobile). Therefore, when the balls 4, 4 previously incorporated in the pockets 10d, 10d are to be later incorporated into the pockets 10e, 10e, the positions indicated by the chain lines in FIG. , A large displacement occurs in the circumferential direction. Therefore, the pockets 10d and 10d into which the balls 4 and 4 are first incorporated must be able to sufficiently tolerate the circumferential displacement of the balls 4 and 4 held inside the respective pockets. On the other hand, the pockets 10e and 10e into which the balls 4 and 4 are to be incorporated later can be displaced in the circumferential direction of each of the balls 4 and 4 based on the joint angle given at the time of use. Is enough. For this reason, as described above, the pockets 10e, 1
The length (L _10e / 3) of each ball of 0e is calculated as the length (L _10d / 2) of each ball of the pockets 10d and 10d.
Smaller than the adjacent pockets 10 in the circumferential direction.
d, the length L ₃₀ over the circumferential direction of the pillar portion 30, 30 that exists between the 10e between can be secured.

In the case of the constant velocity joint of the present invention configured as described above, the total number of the balls 4 and 4 held in each of the pockets 10d and 10e is 10, which has conventionally been generally used. Since the number is larger than the number of balls (six) incorporated in the constant velocity joint, even if a sufficiently large torque can be transmitted, the outer diameter can be reduced, and the configuration can be reduced in size and weight. That is, the basic dynamic load rating of the Zeppa constant velocity joint, which is configured by incorporating the balls 4, 4, is ／ of the number of the balls 4, 4 when the outer diameter of the balls 4, 4 is the same. It is proportional to the power. Therefore, ball 4,
If the number of 4 is large, the basic dynamic load rating can be increased accordingly. In other words, when the required basic dynamic load rating is the same, the outer diameter of each ball 4, 4 is reduced by the number of balls 4, 4, and the outer diameter of the constant velocity joint 1c is reduced. It can be made smaller and smaller and lighter.

Further, in the case of the constant velocity joint 1c of the present invention, the distance between the balls 4 and 4 held in the same pockets 10d and 10e is narrowed, and the distance between the adjacent pockets 10d and 10e in the circumferential direction is reduced. Pillar part 30, 3 existing between
The length dimension of 0 can be increased. Therefore, each of these pillars 3
The stress acting on the connecting portion between the 0 and 30 and the rim portion 31 is relieved to ensure the durability of the retainer 9c, so that the constant velocity joint 1c as a whole has sufficient durability.

In particular, like the constant velocity joint 1c of this embodiment,
If the numbers of the balls 4 and 4 held by the circumferentially adjacent pockets 10d and 10e are different from each other, the balls 4 and 4 can be incorporated into the pockets 10e and 10e having a large number of balls 4 and 4 to be held. by causing later, to allow incorporation of each of these balls 4, 4, moreover can be suppressed that the pockets 10e, the length L _10e of 10e increases. As a result, the number of balls 4, 4 to be incorporated in the constant velocity joint 1c is ten, which is much larger than that of a conventional general structure, and the durability of the retainer 9c can be ensured.

In the illustrated example, each of the pockets 10d, 1d,
0e formed by punching is used. And, with this punching process, each of the column portions 3
FIG. 4A shows the above punching process so that the lengths of 0 and 30 in the circumferential direction are not extremely different between the inner diameter side and the outer diameter side.
As shown in FIG. That is, when the pockets 10d (and 10e) are punched, one circumferential end portion (for example, the right side portion in FIG. 4A) is punched by the punch 49 and then the other circumferential end portion ( For example, a punch 49 is punched out of the left part of FIG. By performing such a process of performing punching in multiple times,
With the circumferential inner surfaces of each of the pockets 10d (and 10e) non-parallel to each other, the circumferential length of each of the column portions 30, 30 is extremely different between the inner diameter side and the outer diameter side. I can do it. Therefore, the cross-sectional area of each of the columns 30, 30 can be sufficiently ensured, and the durability of each of the columns 30, 30 can be ensured. On the other hand, as shown in FIG. 4B, when the punching of each pocket 10d (and 10e) is performed in one behavior, as shown in FIG.
Both inner circumferential surfaces of (and 10e) in the circumferential direction are parallel to each other, and the length of each of the column portions 30, 30 in the circumferential direction is extremely different between the inner diameter side and the outer diameter side. Then, the cross-sectional area of each of the columns 30, 30 becomes small, and it becomes difficult to ensure the durability of each of the columns 30, 30.

Further, in the case of the illustrated example, as described above, the pitch circle diameter of each of the rolling elements 21 constituting the outer row of rolling elements is reduced so that the outer half of the outer race 11 can be formed. The diameter can be reduced. The pitch diameter of the plurality of studs 32 fixed to the second mounting flange 17 provided on the outer peripheral surface of the first inner ring member 14a can be reduced by the reduced outer diameter of the outer half of the outer ring 11. . Therefore, the outer diameter of the second mounting flange 17 for supporting and fixing the stud 32 is reduced without increasing the axial dimension of the first inner ring member 14a, thereby reducing the size and weight of the rolling bearing unit for wheels. Can be achieved more effectively.

As described above, the pitch circle diameter of each of the rolling elements 21 and 21 constituting the outer rolling element row must be smaller than the pitch circle diameter of each of the rolling elements 21 and 21 forming the inner rolling element row. Accordingly, the basic dynamic load rating of the outer rolling element row portion becomes smaller than the basic dynamic load rating of the inner rolling element row portion. Therefore, if the load applied to both rows is the same, the life of the outer rolling element row is shorter than the life of the inner rolling element row. On the other hand, in a general automobile, the load applied to the outer rolling element row portion is smaller than the load applied to the inner rolling element row portion. For this reason, it is easy to design the two row portions to have almost the same life, and it is possible to design without waste. In the illustrated example, balls are used as the rolling elements 21 and 21. However, in the case of a heavy-duty rolling bearing unit for an automobile, tapered rollers may be used as the rolling elements. The present invention is, of course, also applicable to a rolling bearing unit using a tapered roller as a rolling element.

Next, FIG. 5 shows a second example of the embodiment of the present invention corresponding to claim 1. In the case of the present example, four pockets 10f and 10f are formed in the retainer 9d that forms the constant velocity joint 1d. Each of these pockets 10f, 10f holds two balls 4, 4, two in total. Also in the case of such a structure of this example, the interval between the balls 4 and 4 held in the same pockets 10f and 10f is narrowed, and the columns existing between the pockets 10f and 10f adjacent in the circumferential direction are also reduced. The length dimension of the parts 30, 30 can be increased. Then, the durability of the retainer 9d is ensured, and sufficient durability can be obtained for the constant velocity joint 1d as a whole.

Next, FIGS. 6 to 8 show a third embodiment of the present invention corresponding to claim 2. FIG. In the case of this example, six pockets 10g and 10h are formed in the retainer 9e that forms the constant velocity joint 1e. Each of these pockets 10g and 10h has one or two
Each of them holds a total of nine balls 4,4. In the case of such a structure of this example, the same pockets 10h, 10h
The distance between the balls 4 and 4 held in h can be narrowed, and the length dimension of the pillar portions 30 and 30 existing between the circumferentially adjacent pockets 10g and 10h can be increased.

Further, in the case of this example, the number of the pockets 10g and 10h is set to an even number in spite of the odd number of the balls 4 and 4, so that adjacent pockets are used as shown in FIG. Columns 30, 30 existing between 10g and 10h
The distance H between them becomes smaller. Therefore, when the retainer 9e is incorporated into the outer race 3B, as shown in FIGS. 7 and 8, the outer engagement grooves 8, 8 which are circumferentially adjacent to each other on the inner peripheral surface of the outer race 3B.
The shoulder 50 between the pockets 10g of the cage 9e, 1
The holder 9e can be decentered upward in FIGS. 7 and 8 until the shoulder 50 hits the column 30 of the holder 9e. Therefore, the retainer 9e can be incorporated. The reason why the total number of the pockets 10g and 10h is an even number in the present example is to reduce the distance H so that the retainer 9e can be incorporated into the outer ring 3B. In this example, nine balls 4 and 4 are provided. However, when the number of balls 4 and 4 is seven, 1, 1, 1, 1, 1, 2, If it is designed to hold the balls 4, 4, the number of pockets of the cage becomes an even number. In this case, there is a pocket into which one ball is inserted at a diagonal position of 180 degrees of the pocket into which the two balls 4, 4 are inserted, and the distance H between the pillars is
It becomes smaller as in FIG.

[0043]

Since the constant velocity joint of the present invention is constructed and operates as described above, it is possible to reduce the outer diameter by increasing the number of balls for transmitting rotational force to seven or more. By increasing the rigidity of the cage for holding each ball, the durability of the cage can be improved. Therefore, it is possible to reduce the size and weight of the wheel rolling bearing unit, which is called the fourth generation hub unit and integrally incorporates a constant velocity joint, while securing sufficient durability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a rolling bearing unit for a wheel incorporating a constant velocity joint according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line XX of FIG.

FIG. 3 is a cross-sectional view of the retainer, showing a state where a ball is incorporated into a pocket.

4A and 4B are cross-sectional views illustrating a state in which pockets are formed by punching, in which FIG. 4A illustrates a preferable processing, and FIG.

FIG. 5 is a view similar to FIG. 2, showing a second example of the embodiment of the present invention.

FIG. 6 is a view similar to FIG. 2, showing a third example of the embodiment of the present invention.

FIG. 7 is a cross-sectional view showing the state where the retainer is assembled inside the outer race, as viewed from the same direction as FIG.

FIG. 8 is a diagram viewed from the right side of FIG. 7;

FIG. 9 is a cross-sectional view showing a first example of a conventional constant velocity joint with a joint angle provided.

FIG. 10 is a view corresponding to a section taken along line YY of FIG. 9, similarly showing a state where a joint angle is not given;

FIG. 11 is a view of a part of the retainer as viewed from an outer peripheral side.

FIG. 12 is a schematic diagram showing the positional relationship between the bottom surfaces of the inner and outer engagement grooves.

FIG. 13 is a sectional view showing an example of a rolling bearing unit for a wheel in which a constant velocity joint is integrally incorporated.

FIG. 14 is a cross-sectional view schematically showing a part of the constant velocity joint in order to show a force applied to the ball during operation.

FIG. 15 is an enlarged view of a central portion of FIG. 14;

FIG. 16 is a sectional view showing a second example of a conventional constant velocity joint in a state where a joint angle is not provided.

FIG. 17 is a sectional view taken along the line ZZ of FIG. 16;

FIG. 18 is a sectional view of a retainer incorporated in a second example of the conventional structure.

FIG. 19 is a cross-sectional view showing a state in which the inner ring and the outer ring are displaced in a predetermined direction in order to incorporate the ball into the retainer.

FIG. 20 is a sectional view showing a third example of the conventional structure.

[Explanation of symbols]

1, 1a, 1b, 1c, 1d, 1e Constant velocity joint 2, 2A Inner ring 2a Outer surface 3, 3A, 3B Outer ring 3a Inner surface 4 Ball 5 Shaft 6 Shaft 7 Inner engagement groove 7a Bottom surface 8 Outer engagement groove 8a Bottom surface 9, 9a, 9b, 9c, 9d, 9e Cage 10, 10a, 10b, 10c, 10d, 10e, 10
f, 10g, 10h pocket 11 outer ring 12 first mounting flange 13 outer ring track 14, 14a first inner ring member 15, 15a second inner ring member 16, 16a hub 17 second mounting flange 18 first inner ring track 19 Cylindrical part 20 second inner raceway 21 rolling element 22 locking groove 23 locking groove 24 retaining ring 25 step 26 welding 27a, 27b cover 28a, 28b seal ring 29 partition plate part 30 column part 31 rim part 32 stud 33 head Part 34 seal ring 35 meat steal part 36 locking groove 37 retaining ring 38 spacer 39 boot 40 restraining band 41 engaging groove 42 restraining part 43 small diameter cylindrical part 44 circular ring part 45 large diameter cylindrical part 46 combination seal ring 47 space 48 Spline hole 49 Punch 50 Shoulder

Claims (3)

[Claims] 1. An inner ring, an inner engaging groove having an arc-shaped cross section formed at a plurality of positions on an outer peripheral surface of the inner ring, respectively, in a direction perpendicular to a circumferential direction, and an outer ring provided around the inner ring. An outer engaging groove having an arc-shaped cross section formed in a direction perpendicular to the circumferential direction at a position facing the inner engaging grooves on the inner peripheral surface of the outer ring; A retainer sandwiched between the inner peripheral surface and a plurality of circumferentially long pockets formed at positions corresponding to the inner and outer engagement grooves, respectively, in a state of being held inside each of these pockets; , Consisting of a plurality of balls that are free to roll along both the inner and outer engagement grooves, and divides each of these balls into two at the axis intersection angle between the center axis of the inner ring and the center axis of the outer ring. , A constant velocity joint located in a bisector orthogonal to the plane containing these two central axes At least a part of the plurality of pockets is capable of holding a plurality of balls in a single pocket, and the total number of balls is seven or more. Joint. 2. The constant velocity joint according to claim 1, wherein the number of pockets is even, and the number of balls held by each pocket is different. 3. The number of pockets is four and the number of balls is one.
The number of balls held by two pockets existing on the diametrically opposite side is two, and the number of balls held by the remaining two pockets is three each. 2. The constant velocity joint described in 2.