Constant velocity ratio universal joint

A constant velocity ratio universal joint comprising:

• a hollow outer joint member, having an internal surface provided with grooves extending in meridian planes about the axis of the member;
• an inner joint member disposed within the outer joint member, and having an external surface having grooves extending in meridian planes about the axis of the inner joint member, facing the grooves in the outer joint member in pairs;
• a plurality of balls disposed one in each facing pair of said grooves, for torque transmission between the joint members;
• the grooves of each pair diverging from one another towards one end of the joint, and the bases of the grooves in each member being of non-undercut configuration considered from said end of the joint;
• and a cage of annular configuration disposed between the outer and inner joint members and having windows wherein the balls are guided;
• the inner joint member having a part-spherical surface engaging a complementary surface associated with the outer joint member in the region of the axis thereof at said end of the joint;
• the cage having an internal part-spherical surface engaging the part-spherical surface of the inner joint member at the opposite end of the joint, said internal part-spherical surface of the cage ending before a plane containing the centers of the cage windows;
• the external surface of the cage having clearance from the internal surface of the outer joint member between the grooves thereof;
• the balls engaging the grooves in contact tracks such that for each ball its oppositely disposed points of contact with its facing pair of grooves, throughout the entire working range of joint articulation and for all angular positions of joint rotation, provide a cage control angle sufficient to prevent self-inhibition of joint articulation.