JPH0329621Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a constant velocity universal joint used in a driving force transmission shaft of an automobile, etc.

[Conventional technology]

The present applicant has proposed a constant velocity universal joint that is easy to manufacture and can be formed by cold forging ball grooves without undercutting.
We are proposing this. As shown in FIG. 5, this constant velocity universal joint has a concave spherical surface 1a and a concave spherical surface 1a.
an outer joint member 1 having a plurality of ball grooves 1b provided in the outer joint member 1; a convex spherical surface 4a on the outer surface that is slidably fitted to the concave spherical surface 1a of the outer joint member 1; a concave spherical surface 4b on the inner surface; A cage 4 having the same number of ball pockets 4c as ball grooves 1b of the outer joint member 1 penetrating the inner surface, a convex spherical surface 2a that slidably fits into the concave spherical surface 4b of the cage 4, and an outer joint member 1 on the convex spherical surface 2a. An inner joint member 2 having the same number of ball grooves 2b as the ball grooves 1b of The center of curvature OR point and OR' point of the ball grooves 1b and 2b of both inner joint members 1 and 2 are opposite to each other by an equal distance in the axial direction from the center plane Y-Y of the joint on a line parallel to the joint axis X-X. and the amount of eccentricity is at least equal to the distance e from the center plane Y-Y of the joint to the end surface 1' of the outer joint member 1, and
The spherical center a of the outer and inner spherical surfaces 4a and 4b of the cage 4,
The outer and inner spherical surfaces 4a and 4b are eccentrically offset by the same dimension f in the axial direction with respect to the center O of the joint.
are engaged with the inner and outer spherical surfaces 1a and 2a of both the outer and inner joint members 1 and 2, thereby fixing the outer and inner joint members 1 and 2 to each other in the axial direction. , 2, that is, the center plane Y-Y of the joint.

[The problem that the idea aims to solve]

By the way, in this type of constant velocity universal joint, when both the outer and inner joint members 1 and 2 take a large operating angle α as shown in FIG. 6, the ball located on the opening side of the outer joint member 1 3 is held by the ball groove 1b of the outer joint member 1 whose center of curvature is the OR ₁ point, and the ball groove 2b of the inner joint member 2 whose curvature center is the OR ₁ ' point, and torsional torque is applied to the joint. Then, a normal force is applied to the ball 3 from the ball groove 1b of the outer joint member 1 and the ball groove 2b of the inner joint member 2, respectively, and the resultant force _F1 acts on the cage 4. on the other hand,
The ball 3 located at the bottom side of the outer joint member 1 is
The ball is held by the ball groove 1b of the outer joint member 1 whose center of curvature is at the OR ₂ point and the ball groove 2b of the inner joint member 2 whose center of curvature is at the OR ² ' point, and when torsional torque is applied to the joint, the ball A normal force is applied to the cage 3 from the ball groove 1b of the outer joint member 1 and the ball groove 2b of the inner joint member 2, respectively, and the resultant force _F2 acts on the cage 4.

However, since the directions of the resultant force F 1 generated on the ball ₃ located on the opening side of the outer joint member 1 and the resultant force F ₂ generated on the ball 3 located on the deep side of the outer joint member 1 are opposite, the cage 4 is rotated. As the moment acts and the rotational moment acting on the cage 4 increases, the ball 3 moves toward the joint center plane Y-
To avoid deviation from Y, the frictional force acting between the concave spherical surface 1a of the outer joint member 1 and the convex spherical surface 4a of the cage 4 and between the convex spherical surface 2a of the inner joint member 2 and the concave spherical surface 4b of the cage 4 increases. This has the disadvantage of generating heat.

In addition, the rotational moment acting on the cage 4 is
A load is applied to the other balls 3, and the contact force between the balls 3 and the ball grooves 1b, 2b of both the outer and inner joint members 1, 2 increases, resulting in a disadvantage that durability is reduced.

This invention aims to provide a constant velocity universal joint that allows easy machining of ball grooves, suppresses heat generation during operation, and provides a long service life.

[Means to solve the problem]

This invention consists of an outer joint member having a concave spherical surface and a plurality of ball grooves provided on the concave spherical surface, a convex spherical surface on the outer surface that slidably fits into the concave spherical surface of the outer joint member, and a concave spherical surface on the inner surface. a cage having the same number of ball grooves as the ball grooves of the outer joint member penetrating the outer surface thereof, a convex spherical surface slidably fitted into the concave spherical surface of the cage, and a cage having the same number of ball grooves as the ball grooves of the outer joint member on the convex spherical surface. It consists of an inner joint member having a ball groove, and a ball fitted into the ball groove of both the outer and inner joint members and the ball pocket of the cage, and the center of curvature of the ball groove provided in both the outer and inner joint members is aligned with the axis of the joint. A constant velocity universal joint that is eccentric to the opposite side by an equal distance in the axial direction from the center plane of the joint on a parallel line, and the eccentric distance is at least equal to the distance from the center plane of the joint to the end surface of the outer joint member. The bottom side of the ball groove provided in the outer joint member is formed with a radius of curvature smaller than the radius of curvature of the opening side ball groove, and the joining point between the bottom side and the opening side of the ball groove is formed as a joint. The opening side of the ball groove provided in the inner joint member is located on the inner side of the center plane of the outer joint member, and the center of curvature is located at a position symmetrical to the center of curvature of the ball groove on the inner side of the outer joint member with respect to the center plane of the joint. It is designed to hold.

[Effect]

The centers of curvature of the ball grooves provided in both the outer and inner joint members are eccentric to opposite sides by an equal distance in the axial direction with respect to the center plane of the joint on a line parallel to the axis of the joint,
In addition, since the eccentric distance is at least equal to the distance from the center plane of the joint to the end face of the outer joint member, a ball groove shape without undercuts can be obtained, and ironing of the ball groove is easy. This invention furthermore forms the deep side of the ball groove provided in the outer joint member with a radius of curvature smaller than the radius of curvature of the ball groove provided on the opening side, and the ball groove provided in the inner joint member. Since the opening side is formed so that the center of curvature is symmetrical to the center of curvature of the ball groove on the deep side of the outer joint member with respect to the center plane of the joint, even when the joint takes a large operating angle, the center of curvature of the outer joint member is The direction of the resultant force generated on the ball located on the deep side is the same as the direction of the resultant force generated on the ball located on the opening side of the outer joint member, and the resultant forces cancel each other out, reducing the rotational moment acting on the cage.

When the operating angle is set from the joint, the ball swings back and forth within the ball groove with the center of the joint as the center of rotation.
Ideally, the ball should swing along an arc. If the direction of motion is forcibly changed, the force required to change direction will be supported by the ball groove, but the larger the change in direction, the greater the change in inertial force that will occur, which is likely to cause problems such as surface damage. . In this regard, in the constant velocity universal joint of the present invention, both the deep side and the opening side of the ball groove are formed by circular arcs, so there is no large direction change when the ball moves along the ball groove. Therefore, changes in inertial force can also be kept small. Moreover, since the joining point between the deep side of the ball groove and the opening side is not on the center plane of the joint,
In the normal operating angle range of the joint, the balls do not pass through the joint points of the ball grooves, and the above-mentioned ideal state in which there is no change in inertia force is ensured.

〔Example〕

FIG. 1 is a longitudinal sectional view of the main parts showing an embodiment of the constant velocity universal joint according to this invention, and 10 is an outer joint member;
20 is an inner joint member, 30 is a ball, and 40 is a cage.

The outer joint member 10 and the inner joint member 20 include
A plurality of ball grooves 11 and 21 are provided facing each other at equidistant positions on the circumference, and these ball grooves 1
1 and 21 extend in an arc shape along the axis XX of the joint.

That is, the ball groove 11 of the outer joint member 10 is
It is formed by connecting the arc-shaped opening-side ball groove 11a with the center of curvature at the OR point and the arc-shaped deep-side ball groove 11b with the center of curvature at the A point on the same tangent line. The ball groove 21 is
It is formed by connecting an arc-shaped deep ball groove 21a with a center of curvature at point OR' and an arc-shaped opening ball groove 21b with a center of curvature at point A' on the same tangent.

The centers of curvature OR, OR' of the opening side ball groove 11a of the outer joint member 10 and the deep side ball groove 21a of the inner joint member 20 are on the line _X1 - _X1 parallel to the tangent line XX of the joint, eccentric to the opposite side by the same distance eR in the axial direction with respect to the center plane Y-Y of the joint, and the eccentric distance eR is at least equal to the distance from the center O of the joint to the end surface 10' of the outer joint member 10. It has been done.

In addition, the inner ball groove 11 of the outer joint member 10
b and the opening side ball groove 21b of the inner joint member 20
The centers of curvature A and A' are on the axis X-X of the joint,
They are eccentrically spaced equidistantly from the center O of the joint on opposite sides.

On the other hand, the cage 40 has a convex spherical surface 41 and a concave spherical surface 42 having centers of curvature at points a and a' that are eccentric to opposite sides by an equal distance from the center of the joint on the axis XX of the joint, Correspondingly, a concave spherical surface 1 is also eccentrically formed on the outer joint member 10 and the inner joint member 20.
2 and a convex spherical surface 22 are provided, and these are combined in spherical contact. In addition, the cage 40 has a ball pocket 43 penetrating the outer and inner surfaces.
Ball grooves 11, 21 of both outer and inner joint members 10, 20
The same number is provided to correspond to the above.

The ball 30 is connected to both the outer and inner joint members 10 and 2.
0 and the ball pocket 43 of the cage 40, and transmits torque to both the outer and inner joint members 10, 20.

With the above structure, the ball 30 can operate at any operating angle of both the outer and inner joint members 10 and 20.
Axes X-X, X'- of both outer and inner joint members 10, 20
It is held at the bisecting plane of X', that is, the center plane Y-Y of the joint.

As shown in FIG. 2, when both the outer and inner joint members 10 and 20 take a large operating angle α, the resultant force F of the normal force applied to the ball 30 located on the opening side of the outer joint member 10 ₁ is the same as before.
On the other hand, the ball 30 located at the bottom side of the outer joint member 10 has a center of curvature at point A.
is held by the inner ball groove 11b of the inner joint member 20 and the opening ball groove 21b of the inner joint member 20 with the center of curvature at point A', and when torsional torque is applied to the joint,
Normal forces are applied from the deep ball groove 11b of the outer joint member 10 and the opening ball groove 21b of the inner joint member 20, and the resultant force _F2 acts on the cage 40. At this time, the resultant force F ₂ generated on the ball 30 located on the inner side of the outer joint member 10 is such that the center of curvature A point of the inner ball groove 11b of the outer joint member 10 is located on the outer joint member 10 from the center plane Y-Y of the joint. Also, since the center of curvature A' point of the opening side ball groove 21b of the inner joint member 20 is located on the inner side of the outer joint member 10 than the center plane Y-Y of the joint, its direction is outward. The direction is the same as the direction of the resultant force F ₁ generated on the ball 30 located on the opening side of the joint member 10. As a result, the resultant force F ₁ and the resultant force F ₂ cancel each other out,
The rotational moment acting on the cage 40 is reduced.

FIG. 3 is a longitudinal cross-sectional view of a main part showing another embodiment of the constant velocity universal joint according to this invention, and shows the center of curvature of the deep ball groove 11b of the outer joint member 10 and the opening ball groove 21b of the inner joint member 20. A and A' are located apart from the joint axis X-X in the same direction as the curvature center OR point and OR' point of the opening side ball groove 11a of the outer joint member 10 and the deep side ball groove 21a of the inner joint member 20. on the line X _{2 -} As shown in FIG. 4, when both the outer and inner joint members 10, 20 take a large operating angle α, the resultant force F generated on the ball 30 located at the bottom of the outer joint member 10 is similar to the first embodiment. ₂ comes to act in the same direction as the resultant force F ₁ generated on the ball 30 located on the opening side of the outer joint member 10, and the rotational moment acting on the cage 40 becomes smaller.

Each embodiment of this invention has been explained above,
This idea is not limited to these,
Outer joint member 10 with center of curvature at OR, OR' point
the opening side ball groove 11a of the inner joint member 20, the inner side ball groove 21a of the inner joint member 20, and the inner side ball groove 11b of the outer joint member 10 having centers of curvature at points A and A'.
The ball grooves 11 and 21 may be formed by connecting the opening-side ball groove 21b of the inner joint member 20 with a linear or arcuate intermediate ball groove.

[Effect of idea]

In the constant velocity universal joint of this invention described above, the radius of curvature of the ball groove on the deep side of the outer joint member and the ball groove on the opening side of the inner joint member is Because it is smaller than the radius of curvature of the groove, the rotational moment acting on the cage can be reduced, reducing the frictional force acting between the outer and inner joint members and the cage, suppressing heat generation, and reducing the excess load on the balls etc. It has the effect of reducing force and improving durability, and
This does not impair the conventional effect of being able to form ball grooves only by cold forging.

Note that the opening side of the ball groove of the outer joint member and the deep side of the ball groove of the inner joint member may be formed into a straight line from the viewpoint of ease of machining, but in this invention, the opening side of the ball groove of the inner joint member may be formed into a straight line. This minimizes the change in the direction of the force that the ball receives from the ball groove as it moves along the ball groove, making the movement of the ball as smooth as possible and reducing joint life and vibrations such as flaking. This is to prevent the occurrence of phenomena that have an adverse effect on the environment. Furthermore, since the joining point between the deep side of the ball groove and the opening side is offset from the center plane of the joint,
In the normal operating angle range of the joint, the ball does not pass through the junction point, and the influence of changes in the direction of movement of the ball can be avoided.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment of the constant velocity universal joint of this invention, Fig. 2 is a longitudinal sectional view of the constant velocity universal joint in its operating state, Fig. 3 is a longitudinal sectional view of another embodiment of this invention, and Fig. 4 is a longitudinal sectional view of an embodiment of the constant velocity universal joint of this invention. 5 is a longitudinal sectional view of a conventional constant velocity universal joint, and FIG. 6 is a longitudinal sectional view of the conventional constant velocity universal joint in its operating state. 10... Outer joint member, 11... Ball groove, 1
1a...Ball groove on the opening side, 11b...Ball groove on the deep side, 12...Concave spherical surface of the outer joint member, 20...Inner joint member, 21...Ball groove, 21a...Ball groove on the deep side, 21b...Opening Side ball groove, 22...
...Inner joint member convex spherical surface, 30...Ball, 40...
...Cage, 41...Cage convex spherical surface, 42...Cage concave spherical surface, 43...Ball pocket.

Claims (1)

[Scope of utility model registration request] an outer joint member having a concave spherical surface and a plurality of ball grooves provided on the concave spherical surface; a cage having the same number of ball pockets as the ball grooves of the outer joint member penetrating through the cage, a convex spherical surface that slidably fits into the concave spherical surface of the cage, and a convex spherical surface having the same number of ball grooves as the ball grooves of the outer joint member. It consists of an inner joint member, a ball fitted into the ball groove of both the outer and inner joint members, and a ball pocket of the cage, and the center of curvature of the ball groove provided in both the outer and inner joint members is on a line parallel to the axis of the joint. In a constant velocity universal joint, the joint is eccentric to opposite sides by an equal distance in the axial direction with respect to the center plane of the joint, and the eccentric distance is at least equal to the distance from the center plane of the joint to the end surface of the outer joint member, The deep side of the ball groove provided in the outer joint member is formed with a radius of curvature smaller than the radius of curvature of the opening side ball groove, and the joining point between the deep side of the ball groove and the opening side is formed from the center plane of the joint. Position it on the deep side,
The opening side of the ball groove provided in the inner joint member is formed to have a center of curvature at a position symmetrical to the center of curvature of the ball groove on the deep side of the outer joint member with respect to the center plane of the joint. constant velocity universal joint.