GB2312944A

GB2312944A - Constant velocity universal joint

Info

Publication number: GB2312944A
Application number: GB9609378A
Authority: GB
Inventors: Thierry Didier Constantin
Original assignee: Delphi Automotive Systems France
Current assignee: Delphi Automotive Systems France
Priority date: 1996-05-03
Filing date: 1996-05-03
Publication date: 1997-11-12
Anticipated expiration: 2016-05-03
Also published as: GB2312944B; GB9609378D0

Abstract

In a constant velocity universal joint 10 of the cross-groove type comprising an inner race 12 connectable to a first shaft 28 and a substantially annular outer race 14 connectable to a second shaft 34, a ball cage 20 is positioned between the inner race and an intermediate race 16 which itself is positioned adjacent the outer race, First balls 18 are retained by the ball cage 20 and are rotatable in first grooves 36,38 in the inner and intermediate races 12,16 such that the inner race can pivot relative to the outer race, corresponding first grooves being inclined relative to one another in opposed directions. Second balls 22 are rotatable in corresponding second grooves 46, 44 in the outer and intermediate races 14,16 such that the outer race can translate relative to the intermediate race. The construction is to prevent transmission of vibrations between the inner and outer races.

Description

CONSTANT VELOCITY JOINT The present invention relates to a constant velocity joint for the transmission of torque between two rotatable shafts, and in particular to a constant velocity joint of the cross-groove type. The present invention has particular application in motor vehicles, and in particular for providing drive to driven wheels on a motor vehicle.

It is well known to provide a constant velocity joint of the cross-groove type between two rotatable shafts. A cross-groove joint typically comprises an inner race connectable to one shaft, an outer race connectable to the other shaft, and a number of balls retained by a ball cage between the two races. The balls move in associated grooves in the inner and outer race, with the associated grooves being inclined (relative to the rotational axis of the joint) in opposite directions.

During operation, it is possible for any vibrations generated in the outer race to be transferred to the inner race.

It is an object of the present invention to provide a constant velocity joint of the cross-groove type which will substantially overcome the above mentioned problem.

A constant velocity joint in accordance with the present invention for transmitting torque between first and second rotatable shafts, comprises an inner race connectable to the first shaft and rotatable about a first longitudinal axis; a substantially annular outer race surrounding the inner race, connectable to the second shaft, and rotatable about a second longitudinal axis; a ball cage positioned adjacent the inner race and between the inner race and the outer race; an intermediate race positioned adjacent the outer race and between the outer race and the ball cage; a plurality of first balls retained by the ball cage and rotatable in corresponding first grooves in the inner and intermediate races such that the inner race can pivot relative to the outer race, the corresponding first grooves being inclined relative to one another in opposed directions; and a plurality of second balls rotatable in corresponding second grooves in the outer and intermediate races such that the outer race can translate relative to the intermediate race.

The present invention provides a constant velocity joint of the cross-groove type in which the second plurality of balls provide limited additional stroking between the outer race and the inner race to substantially prevent the transmission of vibrations.

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view of a constant velocity joint in accordance with the present invention taken on the line I-I of Figure 2; Figure 2 is a partial cross-sectional view taken on the line II-II of Figure 1; and Figure 3 is a partial cross-sectional view taken on the line III-III of Figure 1.

Referring to the drawings, the constant velocity joint 10 is of the cross-groove type and comprises an inner race 12, an outer race 14, an intermediate race 16, a plurality of first balls 18, a ball cage 20, and a plurality of second balls 22. The inner race 12 is substantially annular and has a bore 24 which has a (first) longitudinal axis X and a splined surface 26. The splined surface 26 allows the inner race 12 to be connected to, and rotate with, a first shaft 28 which is rotatable about the longitudinal axis X. The outer race 14 is substantially cup-shaped and surrounds the inner race 12. The outer race 12 has a base 30 with an upstanding annular wall 32 having a (second) longitudinal axis Y. The base 30 is connected to a second shaft 34 which is rotatable about the longitudinal axis Y. The intermediate race 16 is substantially annular and is positioned adjacent the outer race 14 and between the outer race and the inner race 12. The first balls 18 are positioned in corresponding first grooves 36,38 in the outer surface 40 of the inner race 12 and the inner surface 42 of the intermediate race 16, respectively. The first balls 18 are free to rotate relative to the inner and intermediate races 12,16. The first grooves 36,38 have a substantially semi-circular cross-section in a radial plane (as shown in Figure 1).

The first grooves 36,38 extend in a substantially axial direction which is inclined to the rotational axis X,Y of the cross-groove joint 10, and associated first grooves are inclined relative to one another in opposed directions. The ball cage 20 is substantially annular and is positioned between the inner surface 42 of the intermediate race 16 and the outer surface 40 of the inner race 12, and retain the balls 18 in the cross-groove joint 10. With this arrangement, the constant velocity joint 10 acts as a cross-groove joint.

That is, the inner race 12 can pivot relative to the outer race 14 (axis X can be offset from axis Y - see axis X' in Figure 2), and the inner race can translate (stroke) relative to the outer race.

The second balls 22 are positioned in corresponding second grooves 44,46 in the outer surface 48 of the intermediate race 16 and the inner surface 50 of the outer race 14, respectively. The second balls 22 are free to rotate relative to the outer and intermediate races 14,16. The second grooves 44,46 have a substantially semi-circular cross-section in the radial plane (as shown in Figure 1). The second grooves 44,46 preferably extend in a substantially axial direction which is parallel to the rotational axis X,Y of the cross-groove joint 10, and associated second grooves are substantially parallel to one another. With this arrangement, additional limited relative translational (stroke) movement is possible between the inner race 12 and the outer race 14. The presence of the intermediate race 16 isolates the inner race 12 from any vibrations generated in the outer race 14 (for example, by a vehicle engine). In effect, the intermediate race 16 absorbs any vibrations.

As can be seen, in the preferred embodiment described above, there are six substantially equidistantly spaced second grooves 44,46 with two balls 22 positioned in each pair of corresponding second grooves. Also, there are six substantially equidistantly spaced first grooves 36,38 with a single ball 18 positioned in each pair of corresponding first grooves.

Still further, the diameter of the first balls 18 is greater than the diameter of the second balls 22.

Claims

Claims:

1. A constant velocity joint for transmitting torque between first and second rotatable shafts, comprising an inner race connectable to the first shaft and rotatable about a first longitudinal axis; a substantially annular outer race surrounding the inner race, connectable to the second shaft, and rotatable about a second longitudinal axis; a ball cage positioned adjacent the inner race and between the inner race and the outer race; an intermediate race positioned adjacent the outer race and between the outer race and the ball cage; a plurality of first balls retained by the ball cage and rotatable in corresponding first grooves in the inner and intermediate races such that the inner race can pivot relative to the outer race, the corresponding first grooves being inclined relative to one another in opposed directions; and a plurality of second balls rotatable in corresponding second grooves in the outer and intermediate races such that the outer race can translate relative to the intermediate race.

2. A constant velocity joint as claimed in Claim 1, wherein the corresponding second grooves extend in a direction substantially parallel to one another.

3. A constant velocity joint as claimed in Claim 1 or Claim 2, wherein the balls of the plurality of first balls have a diameter which is greater than the diameter of the balls of the plurality of second balls.

4. A constant velocity joint as claimed in any one of Claims 1 to 3, wherein two balls of the plurality of second balls are positioned in each corresponding second groove.

5. A constant velocity joint as claimed in any one of Claims 1 to 4, wherein the number of balls of the plurality of first balls is six.

6. A constant velocity joint as claimed in any one of Claims 1 to 5, wherein the number of balls of the plurality of second balls is twelve.

7. A constant velocity joint substantially as herein described with reference to, and as shown in, the accompanying drawings.