Patent ID: 8147342

Claim:
A fixed constant velocity universal joint comprising: an outer joint member having a spherical inner surface with an open end and a plurality of track grooves formed on the spherical inner surface, the track grooves each extending along an axis direction toward the open end and being equally spaced apart along a circumference of the spherical inner surface; an inner joint member having a spherical outer surface and a plurality of track grooves corresponding to the track grooves of the outer joint member formed on the spherical outer surface, the track grooves each extending along the axis direction and being equally spaced apart along a circumference of the spherical outer surface; a plurality of balls received in the respective track grooves of the outer and inner joint members so as to transmit torque; and a cage for holding the plurality of balls, the cage being arranged between the spherical inner surface of the outer joint member and the spherical outer surface of the inner joint member, the cage having a spherical outer surface and a spherical inner surface, wherein: a center of the spherical outer surface of the cage and a center of the spherical inner surface of the cage are oppositely offset from a center of the joint by an equal distance along the axis direction; a wall of the cage, as viewed in longitudinal section, is thicker in an area adjacent to the open end of the outer joint member than the wall of the cage in an area away from the open end; the track grooves of the outer joint member each have a bottom linearly tapered in an area adjacent to the open end so that a depth of the grooves increases toward the open end; the track grooves of the inner joint member each have a bottom linearly tapered in an area away from the open end so that a depth of the grooves decreases toward the end of the inner joint member opposite to the open end; and in a position in which an operating angle between a rotation axis of the outer joint member and a rotation axis of the inner joint member is 0°, an end of the spherical outer surface of the cage adjacent to the open end of the outer joint member is axially extended from the open end of the outer joint member, wherein a tapered surface extends from an end of the spherical inner surface of the cage adjacent to the open end of the joint toward the end of the spherical outer surface of the cage adjacent to the open end of the joint such that the tapered surface has an increasing diameter toward the end of the spherical outer surface of the cage, and wherein the tapered surface tapers at an angle which is greater than or equal to half of a maximum operating angle between the rotation axis of the outer joint member and the rotation axis of the inner joint member.