CONSTANT VELOCITY JOINT

Abstract

A constant velocity joint 10 comprises an outer race 12, an inner race 11, balls 14 and a cage 13. The outer race 12 has a partially spherical inner surface 12a provided with plural outer ball grooves 12b. The inner race 11 has a partially spherical outer surface 11 a provided with plural inner ball grooves 11b arranged to correspond to the outer ball grooves 12b. The balls 14 are interposed between the outer ball grooves 12b and the inner ball grooves 11b. The radial distance of the outer ball grooves 12b from the rotational axis of the outer race increases toward an opening end of the outer race 12 in a predetermined zone H, and a contact angle θ between each ball 14 and each outer ball groove 12b decreases toward the opening end of the outer race 12 in the predetermined zone H.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects, features and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description of the preferred embodiments when considered in connection with the accompanying drawings, in which:

FIG. 1 is an axial section view of a constant velocity joint of an embodiment related to the invention;

FIGS. 2( a)-2(c) are explanatory drawings of an outer ball groove of an outer race of the constant velocity joint;

FIG. 3 is an another explanatory drawing of the outer ball groove,

FIG. 4 is a graph of analysis results; and

FIG. 5 shows tables of condition values of the analysis.

Claims

1. A constant velocity joint comprising: a cup-like outer race having a rotational axis and a partially spherical inner surface provided with plural outer ball grooves, wherein, in a predetermined zone of the length of the outer race, a radial distance between the bottom of each outer ball groove and the rotational axis of the outer race invariably increases when moving toward an opening end of the outer race;an inner race having a partially spherical outer surface provided with plural inner ball grooves arranged to correspond in position to the outer ball grooves;plural balls interposed between the outer ball grooves and the inner ball grooves; anda cage interposed between the outer race and the inner race to hold the balls,wherein a contact angle between each ball and each outer ball groove decreases when moving toward the opening end of the outer race in the predetermined zone.

2. The constant velocity joint according to claim 1, wherein: a center of each ball moves linearly in the predetermined zone.

3. The constant velocity joint according to claim 2, wherein: the length of the predetermined zone H (millimeters) and an angle γ (degrees) between a trajectory of the center of each ball moving and a rotational axis of the outer race are linked by a below relation formula, (H+1.3)≦3.8 γ−0.6.

4. The constant velocity joint according to claim 3, wherein: the length H (millimeters) and the angle γ (degrees) are further linked by a below formula, H≧5.8 γ−0.9

5. A constant velocity joint comprising: a cup-like outer race having a rotational axis and a partially spherical inner surface provided with plural outer ball grooves, wherein, in a predetermined zone of the length of the outer race, a radial distance between the bottom of each outer ball groove and the rotational axis of the outer race invariably increases when moving toward an opening end of the outer race;an inner race having a partially spherical outer surface provided with plural inner ball grooves arranged to correspond in position to the outer ball grooves;plural balls interposed between the outer ball grooves and the inner ball grooves; anda cage interposed between the outer race and the inner race to hold the balls,wherein a contact angle between each ball and each outer ball groove invariably decreases when moving toward the opening end of the outer race in the predetermined zone.

6. The constant velocity joint according to claim 5, wherein: a center of each ball moves linearly in the predetermined zone.

7. The constant velocity joint according to claim 6, wherein: the length of the predetermined zone H (millimeters) and an angle γ (degrees) between a trajectory of the center of each ball moving and a rotational axis of the outer race are linked by a below relation formula, (H+1.3)≧3.8 γ−0.6.

8. The constant velocity joint according to claim 7, wherein: the length H (millimeters) and the angle γ (degrees) are further linked by a below formula, H≧5.8 γ−0.9

9. The constant velocity joint according to claim 5, wherein one end of the predetermined zone substantially coincides with the open end of the outer race, such that the outer ball grooves are substantially undercut free.

10. A constant velocity joint comprising: a cup-like outer race having a rotational axis and a partially spherical inner surface provided with plural outer ball grooves, wherein, in a predetermined zone of the length of the outer race, a radial distance between the bottom of each outer ball groove and the rotational axis of the outer race invariably increases when moving toward an opening end of the outer race;an inner race having a partially spherical outer surface provided with plural inner ball grooves arranged to correspond in position to the outer ball grooves;plural balls interposed between the outer ball grooves and the inner ball grooves; anda cage interposed between the outer race and the inner race to hold the balls,wherein the outer ball grooves are substantially undercut free.