Fixed constant velocity universal joint

A fixed type constant velocity universal joint, comprising:

• an outer joint member having eight curved track grooves formed in a spherical radially inner surface so as to extend in an axial direction;
• an inner joint member having eight curved track grooves formed in a spherical radially outer surface so as to extend in the axial direction;
• eight torque transmission balls arranged between the eight curved track grooves of the outer joint member and the eight curved track grooves of the inner joint member corresponding thereto;
• and
• a cage configured to hold the eight torque transmission balls in pockets, the cage having a spherical radially outer surface and a spherical radially inner surface to be fitted to the spherical radially inner surface of the outer joint member and the spherical radially outer surface of the inner joint member, respectively,
• wherein a curvature center of each of the eight curved track grooves of the outer joint member and a curvature center of each of the eight curved track grooves of the inner joint member are offset from a joint center by an equal distance to opposite sides in the axial direction,
• wherein the fixed type constant velocity universal joint has grease sealed therein,
• wherein initial pocket gaps between the pockets and the eight torque transmission balls each have a value that is greater than zero and an upper limit of 20 μm, and
• wherein the grease has an initial consistency equivalent to consistency number 1 or 2, and a mixture stability of from 390 to 440.