Patent ID: 7632190

Claim:
A constant-velocity joint comprising: an outer member connected to one of two shafts which are angularly movable relative to each other and having an inner circumferential surface having a plurality of first guide grooves extending in an axial direction thereof, said outer member having an open end; an inner ring connected to the other of said two shafts and having as many second guide grooves as the number of said first guide grooves, said second guide grooves extending in an axial direction thereof; a plurality of balls rollingly disposed between said first guide grooves and said second guide grooves, for transmitting a torque between said outer member and said inner ring; and a retainer having retaining windows retaining said balls, respectively, therein, wherein each of said first guide grooves has a transverse cross section extending perpendicularly to said axial direction and having a single arcuate shape, each of said first guide grooves being held in contact with a corresponding one of the balls at a single point, and wherein each of said second guide grooves has a transverse cross section extending perpendicularly to said axial direction and having elliptically arcuate shape, each of said second guide grooves being held in contact with a corresponding one of the balls at two points.