Patent ID: 6422946
Filing Date: 2002-07-23
Classification: B21K,F16D,Y10S

Abstract:
An outer race of a universal joint, the outer race comprising:a shaft portion; a cylindrical portion formed on one end of the shaft portion, the cylindrical portion having an inner periphery; a plurality of ball rolling grooves formed on the inner periphery of the cylindrical portion, the cylindrical portion being fabricated by fitting a punch set having a plurality of ridges of a configuration complementary to that of the ball rolling grooves formed on the inner periphery of the cylindrical portion into the inner periphery of the cylindrical portion of the outer race which is a blank, the ball rolling grooves being formed on the inner periphery of the cylindrical portion by ironing with the cylindrical portion being pressure inserted into a die; and a margin recess for a grinding wheel being formed at a base of each ball rolling groove by stopping the ironing operation when the ball rolling grooves are formed to have a predetermined length at the base of the ball rolling grooves by ironing with the cylindrical portion inserted from an opening side thereof, while leaving an inner-most portion of the cylindrical portion intact.