Sliding constant velocity universal joint

A sliding constant velocity universal joint comprising:

• an outer member having an interior surface defining an axial bore, said interior surface of said outer member having a plurality of axially extending grooves and a plurality of axially extending flat portions corresponding in number to the plurality of grooves, each of said plurality of axially extending flat portions extending between and merging into the adjacent two of said axially extending grooves, said plurality of axially extending flat portions forming the sides of a substantially regular polygonal bore.
• a ball cage within said axial bore, said cage having a first curved outer surface portion which engages a portion of each of said flat portions intermediate the adjacent two grooves of said outer member to provide two spaces between said curved exterior surface and said flat portion on opposite sides of said flat portion, said cage having a second curved outer surface portion adjacent one end thereof and a curved inner surface portion adjacent said one end, the center of curvature of said first outer surface portion and the center of curvature of at least one of said second outer surface portion of said cage and inner surface portion of said cage being offset by an equal amount on opposite sides of the joint center along the joint axis;
• an inner member within said ball cage having a curved outer surface portion which engages said inner surface portion of said cage, said inner member having a plurality of grooves corresponding in number to the grooves in said outer member;
• a plurality of balls mounted in grooves between said outer and inner members and retained by said cage;
• and
• a restraining member movable with said inner member and having a curved inner surface which engages said second outer surface portion of said cage to assist in preventing relative axial movement between said cage and inner member in at least one direction.