Tripod type constant velocity universal joint

A tripod type constant velocity universal joint comprising:

• an outer ring having a plurality of raceway grooves extending in an axial direction;
• a tripod including a plurality of tripod shaft portions extending radially outward;
• and
• rollers externally fitted onto the tripod shaft portions and configured to roll in the raceway grooves, wherein:
• the raceway groove includes a first raceway surface constituting one groove side surface, a second raceway surface constituting another groove side surface, and a ceiling surface constituting a groove bottom surface;
• the roller includes
• a roller outer circumferential surface configured to roll on the first raceway surface or the second raceway surface, and
• a roller end face that is an axial end face of the roller that faces the ceiling surface;
• a point located on a central axis of the roller and distant from a central axis of the outer ring on a contour line obtained by projecting the roller end face in the axial direction of the outer ring when the roller pitches by a predetermined pitching angle is defined as a central highest point;
• a boundary point between the roller outer circumferential surface and the roller end face that is located away from the central axis of the outer ring on a contour line obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in a positive direction by a predetermined rolling angle is defined as a positive rotation edge highest point;
• a boundary point between the roller outer circumferential surface and the roller end face that is located away from the central axis of the outer ring on a contour line obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in a negative direction by a predetermined rolling angle is defined as a negative rotation edge highest point;
• and
• a groove-orthogonal sectional shape of the ceiling surface is a line shape passing through the central highest point, the positive rotation edge highest point, and the negative rotation edge highest point.