JP2000065083A - Constant velocity joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the length in the circumferential direction of a column part of a retainer and to secure durability of the retainer without complicating assembly of a ball into a pocket. SOLUTION: A recessed part 46 is circumferentially formed on the opening peripheral edge of an outer ring 41. Even if the inclination of a retainer 9b is small, assembly of a ball 4 into the inside of a pocket 10a (10b) is made possible by virtue of the presence of the recessed part 46. The displacement in the circumferential direction of the ball 4 is restrained, the circumferential length of the pocket 10a (10b) is shortened, and the column part 30 can be lengthened in accordance with the recessed part. The intermediate part outer peripheral part of a shaft of an assembling jig is brought into contact with a smooth edge 48 of the peripheral edge of the recessed part 46. Accordingly, the shaft is not wobbled in assembling work.

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 the outer end of one shaft 5 driven to rotate by the transmission.
Further, the outer wheel 3 is fixed to the inner end of the other shaft 6 for connecting the driving wheels. Six inner engagement grooves 7 having an arc-shaped cross section are formed on the outer peripheral surface 2a of the inner race 2 intermittently and at equal intervals in the circumferential direction, respectively, at right angles to the circumferential direction. ing. On the inner peripheral surface 3a of the outer race 3, six outer engaging grooves 8, 8 also having an arc-shaped cross section are provided at positions opposed to the inner engaging grooves 7, 7 in the circumferential direction. They are formed at right angles.

[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 intermittently in the circumferential direction at positions corresponding to the inner and outer engagement grooves 7, 8, respectively. A total of six balls 4, 4 are held, one each inside 10, 10. These balls 4 and 4 are respectively connected to the pockets 10 and
10, the inner and outer engagement grooves 7,
It can roll freely along 8.

As shown in FIG. 8, each of the pockets 10 and 10 has a rectangular shape which is long in the circumferential direction, and has an axis intersection angle α of 18
When the constant velocity joint 1 is operated in a state of less than 0 degree, even if the distance between the balls 4 adjacent in the circumferential direction changes, the change can be absorbed. That is, the positional relationship between the bottom surfaces 7a, 7a of the inner engagement grooves 7, 7, and the bottom surfaces 8a, 8a of the outer engagement grooves 8, 8 are described.
The positional relationship between them is a relationship like a meridian of a globe as shown by a dashed line in FIG. The center axis of the inner ring 2 matches the center axis of the outer ring 3 (the axis intersection angle α = 180).
°), the balls 4 exist in the vicinity of the position corresponding to the equator of the globe as shown by the two-dot chain line in FIG.
On the other hand, when the center axis of the inner ring 2 and the center axis of the outer ring 3 become inconsistent (axis intersection angle α <180 °), the balls 4, 4 are rotated as the constant velocity joint 1 rotates. 9 in the vertical direction (alternately in the north and south poles of the globe). As a result, the distance between the balls 4 adjacent to each other in the circumferential direction expands and contracts, so that each of the pockets 1
Each of 0 and 10 is a rectangle that is long in the circumferential direction so that the above-mentioned interval can be enlarged or reduced. 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 is clear from the above description. Therefore, the line corresponding to the meridian is
Each of the engagement grooves 7 and 8 exists at a position slightly shifted from each other.

Further, as shown in FIG. 6, regardless of the displacement between the one shaft 5 and the other shaft 6, 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. 10 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. 10) of the outer peripheral surface, and a second mounting flange 17 at the other end (rightward in FIG. 10). The first inner raceway 18 is formed in a cylindrical shape provided for each. On the other hand, the second inner race member 15 has one end (the left end in FIG. 10) as a cylindrical portion 19 for externally fixing the first inner race member 14, and the other end (FIG. 10). (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 (the left end face in FIG. 10) of the second inner race member 15 and the stepped portion 2 formed on the inner peripheral face of the first inner race 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.

Further, between the openings at both ends of the outer race 11 and the outer peripheral surface of the intermediate portion of the hub 16, a substantially cylindrical cover 27a, 27b made of a metal such as a stainless steel plate is provided. Ring seal 28 made of material
a and 28b. These covers 27a, 27
b 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 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. Foreign matter that has entered the inside of the second inner race member 15 from the opening (the left end in FIG. 10) of the second inner race member 15 is prevented from reaching the constant velocity joint 1a. The constant velocity joint 1a is the same as that shown in FIG.
The structure is the same as that of 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 ring 2 is transmitted to the hub 16 including the second inner ring member 15 via the plurality of balls 4, 4, and the wheels are rotationally driven.

In order to further downsize the fourth-generation hub unit as described above, it is effective to reduce the diameter of the circumcircle of a plurality of balls 4 constituting the constant velocity joint 1a. . In order to reduce the diameter of the circumscribed circle, to reduce the diameter of each of the balls 4, 4, and to secure the torque that can be transmitted by the constant velocity joint 1a, the number of the balls 4, 4 must be reduced. Need to increase.
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. Column portions 30, 30 existing between the pockets 10, 10
(See FIGS. 7, 8, 11 to 14) It is necessary to secure a length dimension in the circumferential direction. What if these pillars 3
If the circumferential length of 0, 30 is insufficient,
This is because the strength of the retainer 9 is insufficient, and there is a possibility that damage such as a crack may occur from the peripheral portion of each of the pockets 10 and 10 with use over a long period of time. However, increasing the length of each of the pillars 30, 30 is restricted in terms of preventing interference with the balls 4, 4. That is, first, the length of each of the pockets 10 and 10 in the circumferential direction is determined by setting the constant velocity joint 1a to the joint angle (the positional relationship between the center axis of the inner ring 2 and the center axis of the outer ring 3A is shifted from a linear state. Each of the balls 4 must be large enough to be displaceable in the circumferential direction of the retainer 9 when rotated in a state where the angle of complementation of the axis intersection angle α shown in FIG. There is. Second, the length is the same as that of the constant velocity joint 1.
After assembling the inner ring 2, the outer ring 3A, and the retainer 9, the pockets 10, 1 of the retainers 9, 9 are assembled.
It must be of a size that can accommodate each of the balls 4, 4 within 0.

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 discloses 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 equal intervals (with equal pitch pitch angles) 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 incorporate the balls 4 and 4 into the pockets 10b and 10b. Even in the state where the joint angle is exceeded beyond the maximum value of the joint angle in the use state, the inner surfaces of both ends of the respective pockets 10a and 10a in the longitudinal direction and the respective pockets 10a, 10a,
The ball 4 is set to a size that does not interfere with the balls 4, 4 incorporated in 10a.

[0015] The above-mentioned Japanese Patent Application Laid-Open No. 9-1 is constructed as described above.
According to the constant velocity joint described in Japanese Patent No. 77814, after the balls 4 and 4 are assembled into the long pockets 10a and 10a, the short pocket 10 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. 14, the center axis of the inner ring 2 and the center axis of the outer ring 3 are set to 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. 14 in order to incorporate the balls 4 and 4 into the four pockets 10b and 10b having short lengths, the length is already increased. The balls 4, 4 incorporated in the long pockets 10 a, 10 a are inserted into the pockets 10 a, 10 a in the direction approaching the short pockets 10 b, 10 b, as indicated by the chain arrows in FIG. 13. Is displaced. Then, the central portions of the pockets 10b, 10b having the short length dimension are aligned with the end portions of the inner engagement grooves 7, 7 formed on the outer peripheral surface of the inner ring 2. Therefore, the balls 4, 4 can be reliably incorporated into each of the pockets 10b, 10b.

[0016]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 9-1 is disclosed.
In the case of the constant velocity joint described in Japanese Patent No. 77814, the column portion 3 existing between the pockets adjacent in the circumferential direction is compared with the case where a single kind of pocket is used.
Although the length of 0, 30 in the circumferential direction can be increased,
It's still not big enough. That is, the balls 4 and 4 are largely displaced in the circumferential direction only when the balls 4 and 4 are incorporated into the pockets 10a and 10b of the retainer 9a. The amount of displacement in the circumferential direction of 4, 4 is about half of that at the time of assembling. Further, the displacement amount of each of the balls 4 during the assembling increases as the inclination angle between the central axis of the outer ring 3 and the central axis of the inner ring 2 increases.

Therefore, if the respective balls 4, 4 can be incorporated into the respective pockets 10a, 10b without making the inclination angle between the central axis of the outer ring 3 and the central axis of the inner ring 2 so large, Each of the above balls 4, when assembled
4, the amount of displacement in the circumferential direction is kept small.
The length of 0 and 30 in the circumferential direction can be increased. In view of such circumstances, the present invention realizes a constant-velocity joint that is small and has excellent durability by increasing the length of the column portion to improve the strength of the retainer, and to achieve a large joint. The invention has been made to prevent the generation of shocking impact noise (abnormal noise) and vibration even when the vehicle is driven in a cornered state.

[0018]

The constant velocity joint according to the present invention has an inner ring, like the above-described conventional constant velocity joint.
7 exists intermittently in the circumferential direction of the outer peripheral surface of the inner ring.
The inner engagement groove having an arc-shaped cross section formed at right angles to the circumferential direction, an outer ring provided around the inner ring, and the inner engagement grooves formed on the inner peripheral surface of the outer ring. At the position facing the groove, an outer engagement groove having an arc-shaped cross section formed in a direction perpendicular to the circumferential direction, and sandwiched between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, A retainer in which seven or more pockets are formed intermittently in the circumferential direction at positions aligned with the two outer engagement grooves, and a pair of inner and outer engagement members held one by one inside each pocket; It consists of seven or more balls that can freely roll along the mating groove.
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 present invention, when inserting each of the balls into each of the pockets in the peripheral portion of the opening of the outer ring, interference between the peripheral portion of the opening and each of the balls is prevented. In order to achieve this, a concave portion is formed over the entire circumference, and the outer peripheral edge of the concave portion is a smooth edge that is smoothly continuous over the entire circumference. Also, when the inner ring is inclined with respect to the outer ring in a state where the shaft is inserted into the inner ring without play, the outer peripheral surface of the intermediate portion of the shaft exists in the opening of each of the outer engagement grooves. The contact is made so as to contact the smooth edge without contacting the uneven portion.

[0020]

According to the constant velocity joint of the present invention constructed as described above, the ball can be incorporated into each pocket, and the dimension of the column existing between the pockets adjacent in the circumferential direction can be reduced. With sufficient securing, the durability of the cage can be sufficiently improved. That is, the ball can be incorporated into each of the pockets without making the inclination angle between the center axis of the outer ring and the center axis of the inner ring so much as to form the concave portion at the peripheral edge of the opening of the outer ring. Therefore, the amount of displacement of each ball in the circumferential direction during the assembling operation can be kept small, and the dimensions of the column can be sufficiently ensured.

In a state where a large joint angle is provided, the outer peripheral surface of the shaft inserted inside the inner ring may come into contact with the opening of the outer ring because the inner ring is driven to rotate. The outer peripheral surface of the shaft comes into contact with the smooth edge, and does not come into contact with the uneven portion existing at the opening of each outer engagement groove. Therefore, even if the shaft and the outer ring are displaced in a state where the shaft and the opening of the outer ring are in contact with each other, the outer peripheral surface of the shaft and the uneven portion collide with each other, so that impact striking occurs. There is no sound or vibration. As a result, even when the vehicle is driven with a large joint angle, it is possible to prevent the occurrence of the tapping sound and the vibration and to prevent the occupant or the like from feeling uncomfortable. Further, after the assembly of the constant velocity joint is completed, it is possible to prevent the above-mentioned uneven portion and the outer peripheral surface of the shaft from being damaged during handling until assembly to the automobile. As a result, the constant velocity joint is miniaturized with a structure that does not cause discomfort during driving or damage during handling, and the outer ring of this constant velocity joint and the inner ring of the rolling bearing unit for wheel support are integrated. This can contribute to the practical use of a so-called fourth generation hub unit.

[0022]

1 to 4 show a state in which the present invention is applied to a constant velocity joint constituting a fourth generation hub unit as an example of an embodiment of the present invention. An 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.
On the inner peripheral surface, respectively. On the inner diameter side of the outer ring 11, a hub 33 including a hub body 31 and an inner ring 32 is arranged concentrically with the outer ring 11. Each outer ring track 1 is formed on the outer peripheral surface of the hub 33.
First and second inner ring raceways 18 and 20 are provided in portions facing 3 and 13 respectively. These inner ring raceways 1
The first inner raceway 18 of 8, 20 is formed directly on the outer peripheral surface of the intermediate portion of the hub body 31. Further, in the intermediate portion of the hub body 31, a portion closer to the inner end (closer to the right end in FIG. 1) than the portion where the first inner raceway 18 is formed,
The inner ring 32 is externally fitted. The second inner ring raceway 20
Are formed on the outer peripheral surface of the inner ring 32. Then, each of the outer raceways 13, 13 and the first and second inner raceways 1
8 and 20, a plurality of rolling elements 21,
The hub 33 is rotatably supported by providing the hub 21 inside the outer race 11 by rotatably providing the hub 21.

In the case of the illustrated example, as described above, by forming the first inner raceway 18 directly on the outer peripheral surface of the hub body 31, the diameter of the first inner raceway 18 can be reduced. The diameter is smaller than the diameter of the second inner raceway 20 formed on the outer peripheral surface of the inner race 32. In addition, as the diameter of the first inner raceway 18 is made smaller than the diameter of the second inner raceway 20 in this manner, the outer side facing the first inner raceway 18 (in the width direction when assembled to an automobile). The diameter of the outer raceway 13 on the outer side is referred to as the diameter of the outer raceway 13 on the inner side (the center side in the width direction when assembled to the vehicle, and the right side in FIG. 1). Is also small. Further, the outer race 1 having the outer race 13 formed thereon is formed.
The outer diameter of the outer half of the outer race 11 is smaller than the outer diameter of the inner half of the outer race 11, which is the portion where the inner outer raceway 13 is formed. In the illustrated example, the diameters of the first inner raceway 18 and the outer raceway 13 are reduced as described above.
Are smaller than the number of rolling elements 21 provided between the second inner raceway 20 and the inner outer raceway 13.

A second mounting flange 17 for supporting and fixing wheels to the hub body 31 is provided integrally with the hub body 31 on the outer peripheral surface of the outer end of the hub body 31. The base ends of a plurality of studs 34 for connecting the wheels are fixed to the second mounting flange 17. In the case of the illustrated example, the pitch circle diameter of the plurality of studs 34 is equal to the outer diameter of the outer half of the outer race 11 as described above.
Similarly, the outer diameter of the inner half is made smaller (by the extent that the head 35 of each stud 34 does not interfere with the outer peripheral surface of the outer end of the outer race 11). The diameter of a portion of the outer peripheral surface of the hub main body 31 which is located inward in the axial direction from the portion where the first inner raceway 18 is formed has a rolling element corresponding to the first inner raceway 18. 21 and 21 are smaller than the diameter of the inscribed circle. 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. This is because the hub main body 31 can be freely inserted into the inner diameter side of the outer ring 11 in a state where the seal ring 36 is internally fitted and fixed to the surface. On the outer peripheral surface of the intermediate portion of the hub body 31, between the first inner raceway 18 and the portion where the inner race 32 is externally fitted, a concave groove-like steal portion 37 is formed over the entire circumference. Thus, the weight of the hub body 31 is reduced.

The inner ring 32 externally fitted to the hub body 31
A plurality of rolls 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. In order to maintain the preload applied to each of the rolling elements 21 and 21 at an appropriate value,
A retaining ring 39 is locked in a locking groove 38 formed over the entire circumference in a portion near the inner end of the outer peripheral surface of the hub body 31. The retaining ring 39 is constituted by a pair of retaining ring elements each having a semicircular arc shape. Such a retaining ring 39
In order to apply an appropriate preload to each of the rolling elements 21, the inner peripheral edge thereof is engaged with the locking groove 38 while pressing the inner ring 32 axially outward with respect to the hub main body 31. Let it. The retaining ring 39 should have an appropriate thickness dimension so as to keep the rolling elements 21 and 21 properly preloaded even when the force pressing the inner ring 32 outward in the axial direction is released. Select what you have. That is, as the retaining ring 39, a plurality of types 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 38. A retaining ring 39 having dimensions is selected and engaged with the locking groove 38. Therefore, if the retaining ring 39 is locked in the locking groove 38, even if the pressing force is released, the inner ring 32 is prevented from shifting toward the inner end in the axial direction. Rolling element 2
1, 21 can be maintained with an appropriate preload applied.

Further, in order to prevent a pair of retaining ring elements constituting the retaining ring 39 from being displaced radially outward and to prevent the retaining ring 39 from accidentally falling out of the retaining groove 38,
A part of the spacer 40 is arranged around the retaining ring 39. The spacer 40 is provided with an outer ring 41 for a constant velocity joint provided at an inner end portion of the hub main body 31. Foreign matter such as rainwater and dust enters the constant velocity joint 1c which is an object of the present invention. This is for externally supporting the outer end portion of the boot 42 for preventing the above. The seal ring 36 is provided between the outer peripheral surface of the outer end of the outer ring 11 and the outer peripheral surface of the intermediate portion of the hub body 31. The inner peripheral surface of the inner end of the outer race 11 and the outer peripheral surface of the inner end of the inner race 32 are provided. A combination seal ring 43 is provided between the two surfaces to close the openings at both ends of a space 44 in which the plurality of rolling elements 21 are installed.

Further, the portion of the inner end of the hub body 31 where the inner ring 32 and the outer end of the boot 42 are fitted to each other is, as described above, an outer ring 41 serving as the outer ring of the constant velocity joint 1c. I have. Eight outer engagement grooves 8, 8 each having an arc-shaped cross section, are formed in the inner peripheral surface of the outer ring 41 in a direction perpendicular to the circumferential direction (the left-right direction in FIG. 1). I have. Also, the outer ring 4 is provided inside the outer ring 41.
1, an inner ring 2 for constituting the above-mentioned constant velocity joint 1c of the Zeppa type is arranged. Eight inner engaging grooves 7 are formed on the outer peripheral surface of the inner ring 2 in a direction perpendicular to the circumferential direction. A total of eight balls 4 are provided between each of the inner engagement grooves 7 and 7 and each of the outer engagement grooves 8 and 8, one for each of the engagement grooves 7 and 8.
Is rotatably provided while being held in the pockets 10a and 10b of the retainer 9b. Further, a spline hole 45 is formed in the center of the inner ring 2 in the axial direction. In an assembled state to the automobile, the end of a drive shaft (not shown) is spline-engaged with the spline hole 45, and the hub body 31 is rotatably driven via the inner ring 2 and the eight balls 4, 4. And

The retainer 9b has, for example, the aforementioned FIG.
14, two types of pockets 10a and 10b having different circumferential lengths from each other.
Are provided alternately in the circumferential direction. That is, the pockets 10a and 10a having a large length in the circumferential direction are arranged at every 90 degrees, and the length in the circumferential direction is set at an intermediate position between the pockets 10a and 10a having a large length in the circumferential direction. Small pockets 10b, 10b are arranged. However, the arrangement pitch of the pockets 10a and 10b in the circumferential direction is not necessarily required to be constant.

Further, a concave portion 46 which is a feature of the present invention is formed over the entire periphery of the outer ring 41 at the opening periphery.
When the balls 4, 4 are assembled in the pockets 10 a, 10 b, the recesses 46 cause interference between the balls 4, 4 and the peripheral edge of the opening of the outer ring 41, as shown in FIGS. To prevent. For example, a virtual straight line connecting the end of the outer engagement groove 8 formed on the inner peripheral surface of the outer ring 41 and the joint center opens an angle that is inclined with respect to a virtual plane orthogonal to the center axis of the outer ring 41. In the case of a constant velocity joint having a conventional structure incorporating six balls, as shown in FIG. 5, which has been generally used in the past, the maximum joint angle is about 45 degrees, and the opening angle α ₁ was about 25 degrees. When there are six balls, the opening angle α ₁
Is about 25 degrees, a sufficient length in the circumferential direction of the pillar portions 30, 30 can be secured. On the other hand, when the number of balls is increased to 7 or more (8 in the illustrated example) as in the constant velocity joint of the present invention, the opening angle is reduced, and If the amount of displacement of each of the balls 4 and 4 in the circumferential direction is not reduced, the above-described column portions 30 and
It is impossible to secure a sufficient length in the circumferential direction of 30.

Therefore, in the case of the present embodiment, by forming the concave portion 46, the opening angle α ₂ (FIGS. 2 to 4) can be reduced to 24 degrees or less even when the maximum joint angle is about 45 degrees. The size is smaller than in the case of the conventional structure incorporating six balls. Therefore, even if the displacement (intersection angle) between the center axis of the outer ring 41 and the center axis of the inner ring 2 is relatively small, the balls 4, 4
Can be installed. Therefore, the amount of displacement of each of the balls 4, 4 in the circumferential direction during the assembling operation is smaller than that of the conventional structure. Note that the minimum value of the opening angle α ₂ is regulated within a range where the balls 4, 4 do not fall out of the outer engagement grooves 8, 8 during use. In FIG. 3, θ ₁ , θ ₂
Is the angle at which the retainer 9b must be tilted to incorporate the ball 4 into the pocket 10a (10b) of the retainer 9b, θ ₁ is the case of the conventional structure without the concave portion 46, θ ₂ is the concave portion The case of the structure of the present invention having 46 is shown respectively. The difference between θ ₁ and θ ₂ (and the difference between α ₁ and α ₂ ) can be increased by increasing the width W _{46 of the} concave portion 46. Accordingly, each of the pillars 30,
In order to increase the length of 30 in the circumferential direction, it is desirable to increase the width W _{46 of the} concave portion 46. However, increasing this width W ₄₆ excessively, said opening angle alpha ₂ is excessively small, since each ball 4, 4 is liable to fall off from the respective outer engagement grooves 8, 8 at the time of use, the maximum joint Due to the relationship with the corners, regulations will be made so that they do not fall off.

When the constant velocity joint 1c has a large joint angle, the inner ring 2 is driven to rotate.
The outer peripheral surface of the shaft 47 (FIG. 4) inserted inside the inner ring 2 may come into contact with the opening of the outer ring 41.
According to the present invention, even in such a case, the shaft 47
Has an abutment with the smooth edge 48 and does not come into contact with the uneven portions existing in the openings of the outer engagement grooves 8.
Therefore, even if the shaft 47 and the outer ring 41 are displaced in the circumferential direction in a state where the shaft 47 and the opening of the outer ring 41 are in contact with each other, the outer peripheral surface of the shaft 47 and the concave-convex portion are formed. By hitting, no shocking noise or vibration is generated. As a result, even when the constant velocity joint 1c is operated with a large joint angle, it is possible to prevent the occurrence of the tapping sound and the vibration, thereby preventing the occupant or the like from feeling uncomfortable. Further, after the assembly of the constant velocity joint 1c, it is possible to prevent the uneven portion existing at the opening of the outer ring 41 and the outer peripheral surface of the shaft 47 from being damaged during handling until assembly to the automobile. For this reason, the portion of the end surface 49 of the convex portion existing between the outer engagement grooves 8 and 8 facing the intermediate portion outer peripheral surface of the shaft 47 is provided with the intermediate portion outer peripheral surface. A relief angle is provided to prevent interference.

The function of rotatably supporting the wheel with respect to the suspension device by the wheel rolling bearing unit incorporating the constant velocity joint of the present embodiment configured as described above is achieved by incorporating the conventional constant velocity joint described above. This is the same as in the case of the wheel rolling bearing unit. In the case of a wheel rolling bearing unit incorporating the constant velocity joint of the present invention,
Since the number of the inner and outer engagement grooves 7, 8 constituting the constant velocity joint 1c is eight and the number of the balls 4, 4 is eight, a hub for use in the rolling bearing unit for a wheel is used. The magnitude of the load applied to each of the balls 4 constituting the constant velocity joint 1c during the torque transmission between the inner ring 2 and the inner ring 2 is smaller than that of the conventional structure shown in FIGS. Can be smaller. Accordingly, the outer diameter of each of the balls 4, 4 is reduced accordingly, and the diameter of the circumscribed circle of each of the balls 4, 4 and the circumscribed circle of the plurality of outer engagement grooves 8, 8 are arranged. Diameter can be reduced. The outer diameter of the wheel rolling bearing unit is reduced by the reduced diameter of the circumscribed circle of the outer engagement grooves 8, 8, thereby reducing the size and weight of the entire device.

In particular, in the case of a wheel rolling bearing unit incorporating the constant velocity joint of the present invention, the balls 4, 4 can be incorporated into each of the pockets 10a, 10b provided in the retainer 9b, and the circle The dimensions of the pillar portions 30, 30 existing between the circumferentially adjacent pockets 10a, 10b are sufficiently ensured, and the durability of the retainer 9b can be sufficiently improved. As a result, the constant-velocity joint 1c is miniaturized, and the outer ring 41 of the constant-velocity joint 1c and the hub body 31 that constitutes a rolling bearing unit for supporting wheels are integrated, and a so-called fourth-generation hub unit is put into practical use. Can contribute to

If the outer halves of the outer engagement grooves 8, 8 are arranged on the inner diameter side of the second inner raceway 20, as shown in the illustrated example, the outer diameter of the rolling bearing unit for a wheel can be reduced. Not only that, but also the axial dimension is reduced, the size and weight of the entire apparatus can be more effectively reduced. In such a structure of this example, the second inner raceway 20 constituting the rolling bearing unit body must be larger in diameter than each of the outer engagement grooves 8, 8. The diameter dimension increases. In such a structure of this example, the number of the balls 4, 4 is increased from six to seven.
The effect of the present invention in which the outer diameter of the rolling bearing unit can be reduced by increasing the number of balls and the outer diameter of the balls 4 and 4 by that amount is particularly increased.

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 ring 11 is formed. The diameter can be reduced. The plurality of studs 3 fixed to the second mounting flange 17 provided on the outer peripheral surface of the hub body 31 by an amount corresponding to the reduced outer diameter of the outer half of the outer ring 11.
4 can be reduced in pitch circle diameter. Therefore, without increasing the axial dimension of the hub body 31, the outer diameter of the second mounting flange 17 for supporting and fixing the stud 34 is reduced, thereby reducing the size and weight of the wheel rolling bearing unit. More effectively.

As described above, the pitch circle diameter of each of the rolling elements 21 and 21 constituting the outer rolling element row is 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, applicable to a constant velocity joint integrated with a rolling bearing unit using a tapered roller as a rolling element.

[0037]

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. The strength of the cage for holding each ball can be increased to improve the durability of the cage. 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 sectional view showing an example of a rolling bearing unit for a wheel incorporating a constant velocity joint of the present invention.

FIG. 2 is a sectional view showing a state in which an outer ring and a retainer of a constant velocity joint are taken out, and the retainer is inclined to a state where a ball can be incorporated.

FIG. 3 is a sectional view showing a state where the inner ring is also incorporated.

FIG. 4 is a cross-sectional view showing the relationship between the shaft of the mounting jig and the outer ring in a state where the retainer of the constant velocity joint is inclined with respect to the outer ring so that the balls can be mounted.

FIG. 5 is a sectional view showing a sectional shape of an open end of an outer ring of a conventional constant velocity joint.

FIG. 6 is a sectional view showing a first example of a conventional constant velocity joint in a state where a joint angle is given.

FIG. 7 is also shown without a joint angle;
FIG. 7 is a view corresponding to a cross section taken along line AA of FIG.

FIG. 8 is a view of a part of the retainer as viewed from an outer peripheral side.

FIG. 9 is a schematic diagram showing the positional relationship between the bottom surfaces of the inner and outer engagement grooves.

FIG. 10 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. 11 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. 12 is a sectional view taken along line BB of FIG. 11;

FIG. 13 is a sectional view of a retainer incorporated in a second example of the conventional structure.

FIG. 14 is a cross-sectional view showing a state in which an inner ring and an outer ring are displaced in a predetermined direction in order to incorporate a ball into a cage.

[Explanation of symbols]

 1, 1a, 1b, 1c Constant velocity joint 2 Inner ring 2a Outer surface 3, 3A Outer ring 3a Inner surface 4 Ball 5 Shaft 6 Shaft 7 Inner engaging groove 7a Bottom surface 8 Outer engaging groove 8a Bottom surface 9, 9a, 9b Cage 10, 10a, 10b Pocket 11 Outer ring 12 First mounting flange 13 Outer ring track 14 First inner ring member 15 Second inner ring member 16 Hub 17 Second mounting flange 18 First inner ring track 19 Cylindrical part 20 Second Inner ring raceway 21 Rolling element 22 Lock groove 23 Lock groove 24 Retaining ring 25 Step 26 Welding 27a, 27b Cover 28a, 28b Seal ring 29 Partition plate 30 Column 31 Hub body 32 Inner ring 33 Hub 34 Stud 35 Head 36 Seal ring 37 Meat steal part 38 Locking concave groove 39 Retaining ring 40 Spacer 41 Outer ring 42 Boot 43 Combination seal ring 44 Space 45 Spline hole 46 Recess 47 Shaft 48 Smooth edge 49 End face

Claims (1)

[Claims] 1. An inner engaging groove having an arc-shaped cross section formed at right angles to the circumferential direction at seven or more locations intermittently extending in the circumferential direction of the inner race and the outer peripheral surface of the inner race. An outer ring provided around the inner ring; and an outer ring having an arc-shaped cross-section formed at a position facing the inner engagement grooves on the inner peripheral surface of the outer ring in a direction perpendicular to the circumferential direction. With a groove
A retainer sandwiched between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, and having at least seven pockets formed intermittently in the circumferential direction at positions matching the inner and outer engagement grooves. And seven or more balls that are free to roll along both the inner and outer engagement grooves while being held one by one inside each of these pockets. In a constant velocity joint arranged in a bisecting plane orthogonal to a plane including both the central axes, the axis intersecting angle between the central axis and the central axis of the outer ring is bisected. Then, when inserting each of the balls into each of the pockets,
A concave portion for preventing interference between the peripheral edge portion of the opening and each of the balls is formed over the entire periphery, and the outer peripheral edge of the concave portion is a smooth edge that is smoothly continuous over the entire periphery. When the inner ring is tilted with respect to the outer ring in a state where the shaft is inserted without rattling inside, the outer peripheral surface of the intermediate portion of the shaft is formed on the uneven portion existing at the opening of each outer engagement groove. A constant velocity joint characterized in that it comes into contact with the smooth edge without contacting.