Bearing cup for cruciform shaft type universal joint and manufacturing method thereof, and cross shaft type universal joint

摘要

PROBLEM TO BE SOLVED: To obtain a structure which can secure durability of a universal joint while suppressing wobbling of a pair of yokes with respect to a joint cross, and can prevent an increase of the rotation resistance of both the yokes with respect to shaft parts which constitute the joint cross.SOLUTION: A protrusion 23a which protrudes toward an inside face side of a coupling arm part 15 in a state of being assembled into a disc hole 16 is formed at a center part of an inner face of a bottom plate part 22b which constitutes a bearing cup 17c. In the inner face of the bottom plate part 22b, an annular recessed groove 29 is formed at a portion which surrounds the protrusion 23a, and a plate thickness of the bottom plate part 22b is configured to be thinner than a remaining portion in a portion in which the annular recessed groove 29 is formed. This constitution allows the bottom plate part 22b to be easily elastically deformed in an axial direction.