JP2022179939A - constant velocity joint - Google Patents

Abstract

To provide a constant velocity joint capable of reducing the size while securing durability.SOLUTION: A constant velocity joint includes: an outer member including a bottomed hole; an inner member fitted with an outer periphery of a rotating shaft and inserted into the bottomed hole; a plurality of balls arranged between the outer member and the inner member, and inserted into a plurality of outer side ball grooves provided on an inner wall of the bottomed hole and a plurality of inner side ball grooves provided on an outer wall of the inner member respectively; and a cage for holding the balls. A thickness of a first inner wall portion of the inner wall positioned on an opening side of the bottomed hole is thicker than a thickness of a second inner wall portion of the inner wall positioned on a bottom side of the bottomed hole.SELECTED DRAWING: Figure 2

Description

The present invention relates to constant velocity joints.

A driving force transmission mechanism for a vehicle includes two constant velocity joints as joints for transmitting rotational driving force from a rotating shaft to another rotating shaft. One of the two constant velocity joints is a sliding constant velocity joint and the other is a fixed constant velocity joint. A fixed constant velocity joint is provided between a rotating shaft (for example, a drive shaft) on the differential side and a hub.

A fixed constant velocity joint includes an outer member, an inner member, torque transmission balls interposed between the outer member and the inner member, and a retainer (hereinafter referred to as a cage) that holds the torque transmission balls. The outer member is provided with a substantially truncated conical bottomed hole along its longitudinal direction. Further, the curved inner wall of the bottomed hole is provided with six outer side ball grooves that are equiangularly spaced from each other. Torque transmission balls are inserted into the outer ball grooves.

In order to reduce the size and weight of fixed constant velocity joints, it is known to reduce the thickness of the cage, that is, to make the cage thinner. It is also known that the stiffness of the cage decreases as the thickness of the cage decreases. Further, there has been proposed a technique for ensuring sufficient rigidity even when the thickness of the cage is reduced in order to reduce the weight (see, for example, Patent Literature 1).

JP 2014-219072 A

By the way, when the surface pressure between the torque transmitting balls and the outer ball grooves is high, damage accumulates in the outer ball grooves, causing so-called flaking, in which the surface layer of the outer ball grooves peels off in scales. When flaking occurs, the torque transmission balls may not operate smoothly in the outer ball grooves, and abnormal noise may occur. Therefore, it is required to reduce the size of the constant velocity joint while ensuring the durability of the constant velocity joint.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a constant velocity joint that can be made compact while ensuring durability.

A constant velocity joint according to the present invention includes an outer member including a bottomed hole, an inner member that fits with the outer periphery of a rotating shaft and is inserted into the bottomed hole, and a constant velocity joint between the outer member and the inner member. a plurality of balls arranged and inserted into each of a plurality of outer ball grooves provided on the inner wall of the bottomed hole and a plurality of inner ball grooves provided on the outer wall of the inner member; a cage for holding balls, wherein a thickness of a first inner wall portion of the inner wall positioned on the opening side of the bottomed hole is equal to a thickness of a second inner wall portion of the inner wall positioned on the bottom side of the bottomed hole. It is thicker than the thickness of

In the above configuration, the first inner wall portion is positioned on the opening side of the bottomed hole with respect to the swing center of the outer member, and the second inner wall portion is positioned at the bottomed hole with respect to the swing center. It is good also as a structure located in the bottom side of.

In the above configuration, a configuration including a third inner wall portion that is thinner than the first inner wall portion and thicker than the second inner wall portion between the first inner wall portion and the second inner wall portion may be

ADVANTAGE OF THE INVENTION According to this invention, the constant velocity joint which can be reduced in size can be provided, ensuring durability.

FIG. 1 is an example of an exploded perspective view of a constant velocity joint. FIG. 2 is an example of a ZZ partial sectional view of the outer race. FIG. 3(a) is an example of a graph showing the relationship between the rotational phase and the ball groove load when the operating angle is large. FIG. 3(b) is an example of a graph showing the relationship between the rotational phase and the ball groove load when the operating angle is small.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

As shown in FIG. 1 , the constant velocity joint 10 includes an outer race 11 as an outer member, an inner race 21 as an inner member, balls 31 and a cage (specifically, a ball cage) 33 . For the constant velocity joint 10, a fixed constant velocity joint, such as a Barfield joint, which cannot cope with the distance change of the drive shaft 102, can be adopted.

The outer race 11 is provided at the end of the outer rotary shaft 101 on the hub side (or wheel side). The outer race 11 includes a bottomed hole 11a. The bottomed hole 11a has an inner diameter spherical surface capable of accommodating the inner race 21 therein. The inner wall 11 b of the bottomed hole 11 a of the outer race 11 is provided with a plurality of outer side ball grooves 12 radially continuing from a position coinciding with the axis of the outer rotating shaft 101 . Six outer side ball grooves 12 are provided in this embodiment.

The inner race 21 is provided at the end of a drive shaft 102, which is an example of a rotating shaft. The inner race 21 is fitted to the outer circumference of the end of the drive shaft 102 and inserted into the bottomed hole 11a. The inner race 21 has a spherical surface with an outer diameter such that the outer wall 21a faces the inner wall 11b of the bottomed hole 11a of the outer race 11 with a uniform gap therebetween. A plurality of inner-side ball grooves 22 are formed in the outer wall 21a of the inner race 21 so as to extend radially from a portion aligned with the axis of the drive shaft 102 . Six inner ball grooves 22 are provided in this embodiment.

Ball 31 is arranged between outer race 11 and inner race 21 . The balls 31 are inserted into the plurality of outer ball grooves 12 and the plurality of inner ball grooves 22 respectively. More specifically, the balls 31 are accommodated one by one in the space formed by the outer ball groove 12 and the inner ball groove 22 facing each other while the inner race 21 is accommodated in the outer race 11 . The ball 31 contacts the groove curved surface of the outer ball groove 12 and the groove curved surface of the inner ball groove 22 with the outer peripheral surface 31a of the ball 31 in the facing space of the outer ball groove 12 and the inner ball groove 22. It is rotatably stored in a state where

The cage 33 is positioned between the inner wall of the bottomed hole 11a of the outer race 11 and the outer wall 21a of the inner race 21, and has a curved belt shape with a curvature radius that can move along the respective spherical surfaces. A cage 33 holds the balls 31 . Specifically, the cage 33 is provided with holding windows 33a that are open at equal positions in the circumferential direction corresponding to the facing spaces of the outer ball groove 12 and the inner ball groove 22, and the holding windows 33a are arranged to hold the balls 31 in the facing spaces. is rotatably held. By holding the balls 31 by the holding windows 33a, the balls 31 are prevented from aligning toward one side of the opposing space between the outer ball groove 12 and the inner ball groove 22.例文帳に追加

In the constant velocity joint 10, the inner wall 11b of the bottomed hole 11a of the outer race 11 and the outer wall 21a of the inner race 21 may directly contact each other even when the axial directions of the outer rotating shaft 101 and the drive shaft 102 intersect each other. 31 avoids. Also, in the constant velocity joint 10, such a direct contact is avoided, and the balls 31 are accommodated in the facing space between the outer ball groove 12 and the inner ball groove 22 so as to be free to roll. maintained.

Next, details of the outer race 11 will be described with reference to FIGS. 2 and 3(a) and (b).

The outer race 11 includes three portions as an inner wall 11b, a first inner wall portion 11p, a second inner wall portion 11q, and a third inner wall portion 11r. The first inner wall portion 11p is located on the opening side of the bottomed hole 11a with the pivot center (so-called joint center) C of the outer race 11 as a reference. The second inner wall portion 11q is located on the bottom side of the bottomed hole 11a with the pivot center C of the outer race 11 as a reference. The third inner wall portion 11r is located between the first inner wall portion 11p and the second inner wall portion 11q. The third inner wall portion 11r may be, for example, a portion where the inner wall 11b intersects with a plane S passing through the swing center C and perpendicular to the axial center X of the outer rotating shaft 101 . Note that the first inner wall portion 11p, the second inner wall portion 11q, and the third inner wall portion 11r are formed not only at the bottom of the outer ball groove 12, but also at the inner wall 11b where the outer ball groove 12 is not provided. The parts are similarly provided. That is, the first inner wall portion 11p, the second inner wall portion 11q, and the third inner wall portion 11r are uniformly provided in the circumferential direction of the outer race 11. As shown in FIG.

The thickness of the first inner wall portion 11p is greater than that of the second inner wall portion 11q. Taking the thickness of the third inner wall portion 11r as a reference, the thickness of the second inner wall portion 11q is thinner than the thickness of the third inner wall portion 11r, and the thickness of the first inner wall portion 11p is the thickness of the third inner wall portion 11r. It's thicker. In other words, the third inner wall portion 11r is thinner than the first inner wall portion 11p and thicker than the second inner wall portion 11q. The thickness of the third inner wall portion 11r may be the same as the thickness of either the first inner wall portion 11p or the second inner wall portion 11q. Thus, by changing the thicknesses of the first inner wall portion 11p, the second inner wall portion 11q, and the third inner wall portion 11r, for example, when the third inner wall portion 11r is used as a reference, the rigidity of the second inner wall portion 11q is It is lower than the rigidity of the third inner wall portion 11r. Further, when the third inner wall portion 11r is used as a reference, the rigidity of the first inner wall portion 11p is higher than the rigidity of the third inner wall portion 11r.

Here, when the outer race 11 swings due to the turning of the vehicle and the angle at which the axial directions of the outer rotating shaft 101 and the drive shaft 102 intersect becomes, for example, the maximum operating angle, the ball 31 is positioned near the first inner wall portion 11p. It is displaced to the outer side ball groove 12 . As a result, a strong load due to the balls 31 acts on the outer side ball groove 12 near the first inner wall portion 11p. However, in the present embodiment, the thickness of the first inner wall portion 11p is increased, so the durability of the outer race 11 against the load generated at the maximum operating angle can be sufficiently ensured. That is, the durability of the constant velocity joint 10 can be ensured.

Further, in the present embodiment, since the thickness of the second inner wall portion 11q is made thin, when a strong load acts on the outer side ball groove 12 near the first inner wall portion 11p, the portion near the second inner wall portion 11q is elastically deformed. Transform into That is, the outer race 11 bends outward with reference to the vicinity of the second inner wall portion 11q. As a result, the surface pressure between the outer ball groove 12 near the first inner wall portion 11p and the ball 31 is reduced, and the load acting on the outer ball groove 12 near the first inner wall portion 11p is reduced. More specifically, as shown in FIG. 3A, the load acting on the outer ball groove 12 can be reduced compared to the comparative example in which the thickness of the inner wall 11b of the outer race 11 is not varied. . As a result, it is possible to suppress the occurrence of so-called flaking, in which the surface layer of the outer ball groove 12 peels off like scales.

On the other hand, when the vehicle travels straight and the axial directions of the outer rotating shaft 101 and the drive shaft 102 become linear (specifically, the normal operating angle), the ball 31 is positioned near the second inner wall portion 11q. It is displaced to the outer side ball groove 12 . As a result, a load due to the balls 31 acts on the outer side ball groove 12 in the vicinity of the second inner wall portion 11q. In the case of the normal angle, the load is not as strong as in the case of the maximum working angle. Therefore, even if the thickness of the second inner wall portion 11q is made thin, it is possible to sufficiently ensure durability against the load generated at the normal angle. That is, the durability of the constant velocity joint 10 can be ensured.

Further, in the present embodiment, since the thickness of the second inner wall portion 11q is made thin, even if a load acts on the outer side ball groove 12 near the second inner wall portion 11q, the portion near the second inner wall portion 11q is elastic. Transform into Specifically, the diameter of the opening of the outer race 11 is increased with reference to the vicinity of the second inner wall portion 11q so that the diameter of the opening of the outer race 11 is increased. As a result, the surface pressure between the outer ball groove 12 near the second inner wall portion 11q and the ball 31 is reduced, and the load acting on the outer ball groove 12 near the second inner wall portion 11q is reduced. More specifically, as shown in FIG. 3B, the load acting on the outer ball groove 12 can be reduced compared to the comparative example in which the thickness of the inner wall 11b of the outer race 11 is not varied. . In this way, it is possible to suppress the occurrence of flaking even in the case of the normal angle.

Here, when ensuring the durability of the constant velocity joint 10 in the entire operating range from the normal angle to the maximum operating angle, the outer side ball including both the groove shape corresponding to the normal angle and the groove shape corresponding to the maximum operating angle A groove 12 is preferably provided in the outer race 11 . However, the groove shape of the outer side ball groove 12 is required to be a uniform R shape from the viewpoint of formability. Therefore, it is difficult to provide the outer race 11 with the outer ball groove 12 that includes both a groove shape corresponding to the normal operating angle and a groove shape corresponding to the maximum operating angle. Therefore, in order to ensure the durability of the constant velocity joint 10 in the entire range of use, the constant velocity joint 10 is increased in size without providing a difference in thickness of the inner wall 11b of the outer race 11 as in the comparative example described above. Ensured durability.

However, according to this embodiment, while the groove shape of the outer side ball groove 12 is made into a uniform R shape, by providing a difference in the thickness of the inner wall 11b, even in the case of the maximum operating angle, the normal angle can be changed. Even in such a case, the occurrence of flaking can be suppressed. That is, the durability of the constant velocity joint 10 can be ensured without increasing the size of the constant velocity joint 10 . In this way, the size of the constant velocity joint 10 can be avoided, and as a result, the size of the constant velocity joint 10 can be reduced.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention described in the scope of claims. Change is possible.

10 constant velocity joint 11 outer race (outer member)
11a bottomed hole 11b inner wall 11p first inner wall portion 11q second inner wall portion 11r third inner wall portion 12 outer side ball groove 21 inner race (inner member)
22 inner ball groove 31 ball 33 cage

Claims (3)

an outer member including a bottomed hole;
an inner member that fits into the outer periphery of the rotating shaft and is inserted into the bottomed hole;
a plurality of outer ball grooves arranged between the outer member and the inner member and provided on the inner wall of the bottomed hole; and a plurality of inner ball grooves provided on the outer wall of the inner member. a plurality of balls inserted into each;
a cage that holds the balls;
The thickness of the first inner wall portion of the inner wall positioned on the opening side of the bottomed hole is thicker than the thickness of the second inner wall portion of the inner wall positioned on the bottom side of the bottomed hole,
A constant velocity joint characterized by: The first inner wall portion is positioned on the opening side of the bottomed hole with respect to the swing center of the outer member,
The second inner wall portion is positioned on the bottom side of the bottomed hole with respect to the swing center,
The constant velocity joint according to claim 1, characterized by: Between the first inner wall portion and the second inner wall portion, a third inner wall portion thinner than the first inner wall portion and thicker than the second inner wall portion is included,
3. A constant velocity joint according to claim 1 or 2, characterized in that:

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