Abstract: An outer joint part includes a cup-shaped body portion having a rotation axis. The cup-shaped body portion has an inner circumferential surface having a plurality of circumferentially spaced inner grooves, and an outer circumferential surface having a plurality of outer grooves circumferentially alternately disposed relative to the inner grooves. The wall thickness of the cup-shaped body portion at the outer grooves is smaller than the wall thickness of the cup-shaped body portion in the areas between the outer grooves. A preform formed into the outer joint part includes a bowl-shaped preform portion having a center axis and inner and outer circumferential surfaces similar in shape to each other. The inner circumferential surface defines inner recesses circumferentially spaced from each other. The outer circumferential surface defines outer recesses circumferentially alternately disposed relative to the inner recesses.

Abstract: An apparatus for forming a cup-shaped cage, including a cup-shaped workpiece, an outer die having a center axis and a cavity about the center axis, an inner die coaxially disposed within the cavity of the outer die, and a mandrel adapted to move axially and radially the inner die relative to the outer die. The outer and inner dies have first and second control surfaces which are engaged with outer and inner surfaces of the workpiece, respectively, when the outer and inner dies are in the cooperative press position. The outer die includes a part allowed to be out of contact with the outer surface of the workpiece to permit the movement of the inner die relative to the outer die into the cooperative press position.