Patent ID: 8292749
Filing Date: 2012-10-23
Classification: F16D

Abstract:
1. A fixed type constant velocity universal joint, comprising: an outer joint member in which six track grooves that extend in an axial direction of the outer joint member are formed on an inner spherical surface of the outer joint member; an inner joint member in which six track grooves that extend in an axial direction of the inner joint member are formed on an outer spherical surface of the inner joint member; six torque transmission balls which are arranged in a plurality of ball tracks, each of the ball tracks being formed by one of the track grooves of the outer joint member and one of the track grooves of the inner joint member; and a cage that is interposed between the inner spherical surface of the outer joint member and the outer spherical surface of the inner joint member to hold the torque transmission balls, wherein a center curvature of an outer spherical surface of the cage is offset to a joint opening side with respect to a joint center of the fixed type constant velocity universal joint, and a center curvature of an inner spherical surface of the cage is offset to a joint back side with respect to the joint center, the center curvature of the outer spherical surface and the center curvature of the inner spherical surface being at regular distances from the joint center in opposite directions along a central axis of the fixed type constant velocity universal joint, respectively, wherein the track grooves of the inner joint member are arranged at irregular pitches in a circumferential direction of the inner joint member, and a circumferential length of sections of an opening side end of the inner spherical surface of the outer joint member, which are disposed within a minimum pitch among a plurality of sections of the inner spherical surface of the outer joint member that are arranged between adjacent pairs of the track grooves of the outer joint member, is set to be smaller than a width of a pocket of the cage, wherein a phase of two pitches which are symmetrically positioned with respect to the joint center among pitches between adjacent pairs of the track grooves of the inner joint member is set to be smaller than 60°, a phase of a remaining four pitches is set to be larger than 60°, and the circumferential length of the sections of the opening side end of the inner spherical surface of the outer joint member, which are disposed within the pitches of the phase that are smaller than 60°, is set to be smaller than the width of the pocket of the cage, wherein at least a part of a pillar portion of the cage, which is disposed within the pitches of the phase that are smaller than 60°, is removed to form long pockets that each hold two of the torque transmission balls, and a circumferential length of the long pockets is set to be larger than a width of the inner joint member, and wherein an offset angle θ