Constant velocity ratio universal joint

Claim 1

A constant velocity ratio universal joint, comprising: an outer joint member having a rotational axis; a plurality of ball-receiving tracks in the interior of the outer joint member, spaced circumferentially from one another about said rotational axis and having center lines which lie in meridian planes; an inner joint member having a rotational axis; a plurality of ball-receiving tracks provided on the inner joint member, with center lines which lie in meridian planes about said rotational axis of the inner joint member and facing the tracks of the outer joint member in pairs; a plurality of balls disposed one in each facing pair of tracks in the joint members; the tracks in the joint members being undercut-free considered from one end of the outer joint member; a joint base member attached to the outer joint member at said one end; a control element holding the balls with their centers a common plane, and having an external guide surface; and a part-spherical guide surface engaged by said external guide surface of the control element, said part-spherical guide surface comprising a first portion in said outer joint member between the tracks thereof and a second portion in said joint base member, said first portion being undercut-free considered from said one end of the outer joint member, and said second portion being undercut-free in the opposite axial direction, the outer joint member, at said one end thereof where it is attached to the joint base member, having a surface expanding frusto-conically from the largest diameter of its first part-spherical guide surface portion and the joint base member having a projection with an external surface of frusto-conical configuration and having its undercut-free second portion of the part-spherical guide surface formed with said projection.