Tripod-type constant velocity universal joint

A tripod type constant velocity universal joint comprising:

• an outer joint member that includes track grooves extending in an axial direction at three locations in a circumferential direction, and has a pair of roller guide surfaces on which the track grooves are arranged so as to face each other in a circumferential direction;
• a tripod member that includes three leg shafts protruding in a radial direction;
• a roller that is inserted into the track groove;
• and
• an inner ring that is fitted onto the leg shaft, and rotatably supports the roller,
• wherein a roller unit including the roller and the inner ring is able to swing with respect to the leg shaft,
• the roller unit is configured to be movable in an axial direction of the outer joint member along the roller guide surface,
• a hardened layer is formed on a surface of each leg shaft of the tripod member by carburizing, hardening, and tempering,
• the tripod member is made of a steel material having a carbon content of 0.23% to 0.44%, and
• an effective hardened layer depth of the hardened layer by using, as a Ts torque, 0.3 times a minimum static torsional torque at which a shaft coupled to the tripod member causes torsional fracture and 600 HV as limit hardness is equal to or greater than a maximum shear stress depth when the Ts torque is applied.