BALL TYPE CONSTANT-VELOCITY JOINT

PROBLEM TO BE SOLVED: To provide a ball type constant-velocity joint that can reduce transmission of vibration.SOLUTION: In an inner ring 30, a boundary part 33 between an end face 32 at a bottom side and a convex outer spherical surface 31 of the inner ring 30 is formed into a curved convex axial cross-sectional shape, connecting in a continuous curved surface state with respect to the end face 32 and to the convex outer spherical surface 31, and formed to have the same axial cross-sectional shape over the whole perimeter in the circumference direction. A radius Rc of curvature in the axial cross-sectional shape of the boundary part 33 is set to be smaller than a radius Rb of a concave inner spherical surface 52 of a cage 50. During transmitting a torque, the boundary part 33 of the inner ring 30 contacts with the concave inner spherical surface 52 of the cage 50.