Patent ID: 7591729

Claim:
A double constant velocity universal joint, comprising: two constant velocity universal joints, each constant velocity universal joint including a cylindrical outer joint member with a plurality of axially extending guide grooves in a spherical inner circumferential surface thereof, an inner joint member with a plurality of axially extending guide grooves formed in a spherical outer circumferential surface thereof, torque transmitting balls each arranged in ball tracks formed by both the guide grooves of the outer joint member and the inner joint member, a retainer for retaining the balls, and a cover member attached to a shaft that is connected to the inner joint member, the cover member having an inner spherical surface that makes sliding contact with an outer circumferential surface of the outer joint member, wherein the outer joint members are coaxially united at back surfaces thereof, wherein an outside diameter of the outer joint members at the back surfaces is smaller than the largest outside diameter of the outer joint members so that the outer joint members do not interfere with the cover members, and wherein a grease supply part is provided at a portion of the outer circumferential surfaces of the outer joint members at the back surfaces of the outer joint members so as to supply grease to an interior of the outer joint members, wherein the grease supply part is arranged so as not to protrude from the outer circumferential surfaces of the outer joint members to an exterior of the outer joint members.