JPH07269586A - Constant velocity joint - Google Patents

Abstract

PURPOSE:To improve the rotation fatigue strength of a cage, by providing at least three recessed and projecting circular arc form ball grooves whose radius centers are offset, on the circumference, and forming other ball grooves other than the above ball grooves by the recessed and the projecting circular arcs making the positions on a constant velocity bisection angular line as the radius centers. CONSTITUTION:A recessed circular arc form ball groove 12 with the radius r1 extending in the axial direction, making a position offset from a constant velocity bisection angular line Y to an opening 11a side as the center O1; and a recessed circular arc form ball groove 12a with the radius r3 extending in the axial direction with no offset, making the position O3 on the line Y as the center; are formed alternately with equal angular interval, on the inner peripheral surface of an outer race 11. A projecting circular arc form ball groove 15 with the radius r2 extending in the axial direction, making the position offset from the line Y to the other end 11b side as the center O2; and a projecting circular arc form ball groove 15a with the radius r4 without offset, making the position O3 on the line Y as the center; are formed at the corresponding position of the ball groove 12, on the projecting spherical surface of the outer peripheral surface of an inner race 14. Consequently, the ball pressing force is reduced, and the rotating fatigue strength can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant velocity joint used for a driving force transmission shaft of an automobile.

[0002]

2. Description of the Related Art As shown in FIGS. 6 and 7, this type of constant velocity joint has a spherical inner peripheral surface on one side of a constant velocity bisecting line Y (for example, on the side of the opening 11a of the outer race 11). The outer race 11 having the driven shaft 10 at one end is formed with concave arc-shaped ball grooves 12 extending in the axial direction in a concave arc having a radius r1 centered on the offset position.
And a spline-fitted one end of a drive shaft 13 having the same axis as the driven shaft 10 and having a convex spherical surface on the outer peripheral surface, the convex spherical surface corresponding to the concave arc-shaped ball groove 12 of the outer race 11. In addition, a convex arc-shaped ball groove 15 extending in the axial direction is formed by a convex arc having a radius r2 centered on a position offset to the other side (for example, the other end 11b side of the outer race 11) from the constant velocity bisecting line Y. Between the formed inner race 14, a ball 16 rotatably interposed between the concave arc-shaped ball groove 12 and the convex arc-shaped ball groove 15, and between the outer race 11 and the inner race 14. Cage 1 which is rotatably interposed and holds the ball 16 by a holding window 17a
7 and 7.

[0003]

In such a constant velocity joint, in order to hold the ball 16 on the constant velocity bisecting surface, the concave arc-shaped ball groove 12 and the convex arc shape are formed by the above-described arc formation. The ball groove 15 has a wedge shape that widens toward the opening 11a side of the outer race 11, and the cage 17 prevents the ball 16 from jumping out. Then, as shown in FIG. 7, when the maximum joint angle becomes large, the rotational fatigue strength of the cage 17 decreases due to the pop-out force of the balls 16, which is a neck when the joint angle is made large.

Factors that reduce the rotational fatigue strength of the cage 17 will be described below. As shown in FIG. 7, when the joint is subjected to a torque, the inner groove of the inner race 14 and the ball groove 12 of the outer race 11 move as shown in FIG.
Since it has a wedge shape that widens toward the opening 11a side of No. 1, a pushing force is generated in the direction of the opening 11a side of the outer race 11. As a result, the cage 17 moves toward the opening 11a side of the outer race 11.

At this time, as a reaction force of the ball pushing force, the outer race 11 moves toward the other end 11b side of the outer race 11 with respect to the cage 17, and the cage 17 has an end portion on the opening 11a side of the outer race 11 as shown in FIG. At the interference range L1.

Further, the inner race 14 moves toward the other end 11b side of the outer race 11 with respect to the cage 17 by the reaction force of the ball pushing force, and the cage 17 moves to the inner side of the inner race 14 as shown in FIG. That is, the other end 11b of the outer race 11 is constrained within the interference range L2.

As a result, as shown in FIG. 10, the cage 1
7, the reaction force Fa is applied by the load Fc from the ball due to the restraint points A1, A2 by the outer race 11, and the load F at the restraint points B1, B2 by the inner race 14 is applied.
The reaction force Fb acts by b1.

Due to the reaction force Fb and the load Fc from the ball, the ball 16 in the cage 17 shown in FIG.
As shown in FIG. 12, the pillar portion 17b between the holding windows 17a of the cage 17 has a tensile force M1 and a bending force M1 in both directions of the cage 17, as shown in FIG.
2 acts to repeat large deformation, and the rotational fatigue strength of the cage 17 is reduced.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. The characteristic feature of the present invention is that the spherical inner peripheral surface has a constant velocity bisector. A concave arc-shaped ball groove extending in the axial direction with a concave arc whose center is offset to the side is formed at equal angular intervals, and an outer race having one end opened, and a convex spherical surface on the outer peripheral surface,
The convex spherical surface extends in the axial direction in a convex arc whose radius center is at a position corresponding to the concave arc-shaped groove of the outer race and offset from the constant velocity bisecting line to the side opposite to the one side. An inner race with a convex arc-shaped ball groove,
A ball rotatably interposed between the concave arc-shaped ball groove and the convex arc-shaped ball groove, and a cage rotatably interposed between the outer race and the inner race to hold the ball. In the constant velocity joint consisting of, at least three concave arc-shaped ball grooves and convex arc-shaped ball grooves whose radial centers are offset are provided on the circumference, and the other ball grooves are formed at constant velocity bisecting angles. It is formed by a concave arc and a convex arc whose radial center is on the line.

[0010]

With the above structure, the ball ejection force when the joint angle is increased and the cage restraint point at the opening side end of the outer race are the same as before, but the multiple ball grooves are not offset. ,
The wedge action that gives the pushing force of the ball with a ball included angle of 0 ° is not performed. Therefore, the total pushing force of all the ball grooves is reduced, the tensile force and the bending force in both directions of the cage are reduced, and the cage deformation due to this is reduced, thereby improving the rotational fatigue strength of the cage.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 11 denotes an outer race having a spherical inner peripheral surface, and a center 01 is a position offset from the constant velocity bisector Y to the opening 11a side of the outer race 11 on the spherical inner peripheral surface. A concave arc-shaped ball groove 12 extending in the axial direction with a concave arc having a radius r1 and an concave concave arc having a radius r3 centered at 03 on the constant velocity bisecting line Y and extending in the axial direction. The concave arc-shaped ball grooves 12a are formed at equal angular intervals and are alternately formed. The other end 11b of the outer race 11 is provided with the driven shaft 10. The concave arcuate grooves 12 and 12a are generally formed by six grooves.

Reference numeral 14 denotes an inner race, which is spline-fitted to one end of a drive shaft 13 having the same axis as the driven shaft 10 and has a convex spherical surface on its outer peripheral surface. At a position corresponding to the arc-shaped ball groove 12, the outer race 11 is drawn from the constant velocity bisector Y.
Of the ball groove 15 in the shape of a convex arc extending in the axial direction with a convex arc of radius r2 whose center is at a position offset to the side of the other end 11b opposite to the side of the opening 11a, and the concave arc shape that does not offset. At a position corresponding to the ball groove 12, a constant velocity 2
A convex arc-shaped ball groove 15a having a radius r4 and having a center 03 on the equiangular line Y is formed.

A ball 16 is rotatably interposed between each of the concave arcuate grooves 12 and 12a and the convex arcuate grooves 15 and 15a, and the ball 16 is interposed between the outer race 11 and the inner race 14. A cage 17 that holds the ball 16 in a holding window 17a is rotatably interposed.

As a modification of the above construction, as shown in FIG. 3, a concave arc-shaped ball groove 12a and a convex arc-shaped ball groove 1 are provided.
The arc center of 5a does not necessarily have to be centered on the constant velocity bisecting line Y, and is smaller than the offset amount of the concave arc-shaped ball groove 12 and the convex arc-shaped ball groove 15 having the offset arc centers. Center 031,0 offset by an amount
It may be 32, and in this case, the ball included angle is not zero.

Further, as shown in FIG. 4, the concave arc-shaped ball groove 12a and the convex arc-shaped ball groove 15a are basically a non-offset concave centered on the constant velocity bisector Y. The circular arc and the convex arc are the same, but the undercut free joint in which the offset concave arc-shaped ball groove 12 and the non-offset concave arc-shaped ball groove 12 have straight portions 12c and 12d at the end of the outer race 11 on the side of the opening 11a is formed. Can also be

Further, as shown in FIG. 5, the concave arc-shaped ball groove 12a and the convex arc-shaped ball groove 15a are basically a non-offset concave centered on the constant velocity bisecting line Y. The arc and the convex arc are the same, but the arc center 033
May be on the opposite side beyond the center line of the drive shaft 13, and the concave arc and the convex arc may be large arcs.

In any of the modified examples, the offset concave arc-shaped ball groove 12 and the convex arc-shaped ball groove 15 are wedge-shaped and widen toward the opening 11a side of the outer race 11, and the ball 16 is pinched. The concave arc-shaped ball groove 12a and the convex arc-shaped ball groove 15a which have an angle and are not offset have a grip angle of the ball 16 of 0 ° or 0 °.
The included angle is close to °.

Therefore, according to the present invention having the above-mentioned structure, FIG.
As shown in Fig. 6, the ball ejection force and the cage restraint point at the opening side end of the outer race when the joint angle is increased to 50 ° are the same as in the conventional case. When the convex arc-shaped ball grooves 15 and 15a are formed by a plurality of general six grooves, a concave arc-shaped ball groove 12a and a convex arc-shaped ball groove 15a, which are not offset by half, are provided. Is a ball grip angle of 0 ° or close to 0 °,
Since the wedge action that gives the pushing force of the ball is not performed, the total pushing force of all the ball grooves becomes small.

As a result, the tensile force M1 and the bending force M2 in both directions of the cage 17 are reduced. This cage 17
By reducing the tensile force M1 and the bending force M2 in both sides of the cage 17, the deformation of the cage 17 is reduced and the rotational fatigue strength of the cage 17 is improved.

In the above-mentioned embodiment, the example in which the ball grooves whose arc centers are offset and the ball grooves which are not offset are alternately arranged on the circumference has been described. However, the ball grooves on the offset side have an adjacent relative angle of less than 180 °. At least three ball grooves may be formed, and the other ball grooves may be formed by an arc centered on the constant velocity bisector.

[0021]

As described above, according to the present invention, the spherical inner circumferential surface extends in the axial direction with a concave arc centered at a position offset to one side from the constant velocity bisecting line as the radial center. A concave arc-shaped ball groove is formed at equal angular intervals, an outer race having one end opened, and a convex spherical surface on the outer peripheral surface. A constant velocity 2 is provided at a position of the convex spherical surface corresponding to the concave arc groove of the outer race. An inner race having a convex arc-shaped ball groove extending in the axial direction with a convex arc whose center is a radius offset from the one side of the equiangular line, and the concave arc-shaped ball groove. In a constant velocity joint comprising a ball rotatably interposed between a ball groove having a convex arc shape and a cage holding the ball rotatably interposed between the outer race and the inner race. , Before the radius center is offset A configuration in which at least three concave arc-shaped ball grooves and convex arc-shaped ball grooves are provided on the circumference, and the other ball grooves are formed by a concave arc and a convex arc whose radial center is on the constant velocity bisector. Therefore, even if the joint angle is set to a large angle, some ball grooves that do not have a ball grip angle do not give the ball pushing force, so the total ball pushing force becomes small, and based on this, the cage 1 is deformed. To improve the rotational fatigue strength of the cage.

Further, since the pushing force of the cage is reduced by the balls, the force applied to the restraining points between the cage and the outer race and between the cage and the inner race is reduced, and the heat generated by the slippage is suppressed, and the life of the grease deteriorates. The decrease can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of a constant velocity joint according to the present invention.

FIG. 2 is a sectional view of a constant velocity joint according to the present invention in a bent state at a large angle.

FIG. 3 is an explanatory diagram of a modified example of the present invention.

FIG. 4 is an explanatory diagram of a modified example of the present invention.

FIG. 5 is an explanatory diagram of a modified example of the present invention.

FIG. 6 is a sectional view of a conventional constant velocity joint.

FIG. 7 is a sectional view of a conventional constant velocity joint in a bent state at a large angle.

FIG. 8 is a constraint state diagram of the outer race and the cage in a bent state at a large angle.

FIG. 9 is a restraint state diagram of the inner race and the cage in a bent state at a large angle.

FIG. 10: Cage force balance style diagram

FIG. 11 is a perspective view of a cage.

FIG. 12 is an explanatory diagram of tensile force and bending force that act on the cage.

[Explanation of symbols]

 10 Driven shaft 11 Outer race 12 Offset concave arc-shaped ball groove 12a Offset-free concave arc-shaped ball groove 13 Drive shaft 14 Inner race 15 Offset convex arc-shaped ball groove 15a Offset-free convex arc-shaped ball groove 16 Ball 17 cage

Claims (1)

[Claims] 1. A concave arc-shaped ball groove extending in the axial direction with a concave arc whose center is a radius offset to one side from a constant-velocity bisecting line on a spherical inner peripheral surface is equiangularly spaced. And an outer race having one end opened and a convex spherical surface on the outer peripheral surface, and the convex spherical surface at a position corresponding to the concave arc-shaped groove of the outer race and the one side from the constant velocity bisector. Between the inner race formed with a convex arc-shaped ball groove extending in the axial direction with a convex arc whose center is the position offset to the opposite side, and the concave arc-shaped ball groove and the convex arc-shaped ball groove In a constant velocity joint comprising a ball rotatably interposed between the outer race and an inner race and a cage holding the ball rotatably interposed between the outer race and the inner race, the concave circle with the radial center offset An arc-shaped ball groove and a convex arc-shaped ball A constant velocity joint characterized in that at least three groove grooves are provided on the circumference, and the other ball grooves are formed by a concave arc and a convex arc whose radius center is on the constant velocity bisecting line.