Tripod type constant velocity universal joint

A tripod type constant velocity universal joint, comprising:

• an outer joint member being coupled to and adapted to be torque transmittable to a first rotary shaft and having track grooves extending in an axial direction at trisected positions in a circumferential direction on the inner circumferential surface thereof;
• an inner joint member being coupled to and adapted to torque transmittable to a second rotary shaft and comprising a boss directly connected to the second rotary shaft and journals protruding in the radial direction from the circumferentially trisected positions of the boss;
• and
• a roller cassette lying between the outer joint member and the inner joint member for transmitting torque comprising an outer roller adapted to roll along the track grooves of the outer joint member, inner roller fitted to the journal of the inner joint member and a plurality of rolling elements disposed between the outer roller and the inner roller,
• wherein Do denotes the outside diameter of the outer roller, To the radial wall thickness of the outer roller, t1 the collar thickness on the outside of the joint radial side of the outer roller, t2 the collar thickness on the inside of the joint radial side of the outer roller, Di the outside diameter of the inner roller, Ti the wall thickness of the inner roller, Dj1 the diameter in the joint peripheral direction of the cross-sectional shape at the joint of trunnion journal, Dj2 the diameter in the joint axial direction of the cross-sectional shape at the joint of trunnion journal, and D the trunnion journal pitch circle diameter (PCD) of the joint;
• then, in the event that it is defined that the outside diameter ratio of the outer roller Dor=Do/D, wall thickness ratio Tor=To/D, outer collar thickness ratio t1r=t1/D, inner collar thickness ratio t2r=t2/D, outside diameter ratio of inner roller Dir=Di/D, wall thickness ratio Tir=Ti/D, joint circumferential diameter ratio at the joint of trunnion journal Dj1r=Dj1/D, and joint axial diameter ratio at the joint of trunnion journal Dj2r=Dj2/D, each of the above-mentioned ratios is set to the range of 0.80<Dor<0.90, 0.105<Tor<0.115, 0.025<t1r<0.045, 0.025<t2r<0.075, 0.53<Dir<0.63, 0.065<Tir<0.085, 0.32<Dj1r<0.42, and 0.32<Dj2r<0.35.