Patent ID: 8311457

Claim:
A constant velocity joint, comprising: a first rotation body including a cup-shaped cup unit including a closed end, one open end, an outer ring between the open and closed ends, an inner ring inside the outer ring, and an annular space, the annular space extending between the outer ring and the inner ring, a plurality of grooves on at least one of an inner surface of the outer ring and an outer surface of the inner ring, the grooves aligned in a circumferential direction and extending in an axis direction of the annular space, a shaft projecting from the closed end of the cup unit and extending on a central axis line of the cup unit, and at least one rib projecting from the closed end of the cup unit to connect the cup unit with the shaft; and a second rotation body including a ball holder to hold a ball in each of a plurality of through holes, the through holes being on a cylindrical peripheral wall and aligned in a peripheral direction thereof, wherein one of the first rotation body and the second rotation body is configured to transmit a rotational driving force to other one of the first rotation body and the second rotation body through the balls while the ball holder is inserted into the annular space and the balls held by the ball holder are engaged in the grooves within the annular space, the cup unit, the at least one rib, and the shaft are one piece and include a resin material, and a plurality of ribs are aligned in a rotational direction of the shaft at associated pitches.