Double offset constant velocity joint

A double offset constant velocity joint comprising:

• an outer ring that is cylindrical and that has a plurality of outer ring ball grooves extending in an axial direction on an inner peripheral face of the outer ring;
• an inner ring that is disposed inside the outer ring and that has a plurality of inner ring ball grooves extending in the axial direction on an outer peripheral face of the inner ring;
• a plurality of balls for transmitting torque, the balls being rollably provided between the respective outer ring ball grooves and the respective inner ring ball grooves;
• and
• a cage for holding the plurality of balls between the outer ring and the inner ring, wherein
• the cage has a spherical outer face and a spherical inner face, and a center of the spherical outer face and a center of the spherical inner face are offset to opposite sides in the axial direction with respect to a joint center,
• the outer ring has first wall portions in which the outer ring ball grooves are formed, and second wall portions that are situated on both sides of the first wall portions in a circumferential direction, and outer faces of the first wall portions protrude outward in a radial direction beyond outer faces of the second wall portions, and
• a thickness (Ta) of the first wall portions at contact portions with the balls for torque transmission between the outer ring and the inner ring, a thickness (Tb) of the first wall portions at groove bottoms of the outer ring ball grooves, and a thickness (Tc) of the second wall portion, are set to values that satisfy the following Expression (1):
• Ta
• >
• Tc
• ≥
• Tb
• .
• (
• 1
• )