Fixed constant velocity universal joint

A fixed type constant velocity universal joint comprising:

• an outer joint member having a plurality of track grooves formed in an inner spherical surface thereof;
• an inner joint member having a plurality of track grooves, which are paired with the track grooves of the outer joint member, formed in an outer spherical surface thereof;
• a plurality of torque transmission balls, which are arrayed in a plurality of torque transmitting ball tracks that are each formed by one of the track grooves of the outer joint member and a corresponding one of the track grooves of the inner joint member;
• and
• a cage, which is interposed between the inner spherical surface of the outer joint member and the outer spherical surface of the inner joint member, and is configured to retain the plurality of torque transmission balls,
• wherein the plurality of torque transmitting ball tracks comprise six torque transmitting ball tracks, which are defined as a first track, a second track, a third track, a fourth track, a fifth track, and a sixth track along a circumferential direction,
• wherein an axial offset amount of a curvature center of each of the plurality of track grooves of the outer joint member and an axial offset amount of a curvature center of each of the plurality of track grooves of the inner joint member is set to 0,
• wherein the plurality of track grooves of the outer joint member and the plurality of track grooves of the inner joint member are each inclined with respect to an axis line,
• wherein, in each of the plurality of torque transmitting ball tracks, the one of the plurality of track grooves of the outer joint member and the corresponding one of the plurality of track grooves of the inner joint member, which are opposed to each other, are inclined with respect to the axis line in opposite directions so that inclination angles of the plurality of torque transmitting ball tracks adjacent to each other in the circumferential direction are set to be different from each other, and
• wherein, when crossing angles being the inclination angles of the first track, the third track, and the fifth track are set to be the same and are each defined as γ1, and crossing angles being the inclination angles of the second track, the fourth track, and the sixth track are set to be the same and are each defined as γ2, a relationship of γ1>γ2 is satisfied.

A fixed type constant velocity universal joint comprising:

• an outer joint member having a plurality of track grooves formed in an inner spherical surface thereof;
• an inner joint member having a plurality of track grooves, which are paired with the track grooves of the outer joint member, formed in an outer spherical surface thereof;
• a plurality of torque transmission balls, which are arrayed in a plurality of torque transmitting ball tracks that are each formed by one of the track grooves of the outer joint member and a corresponding one of the track grooves of the inner joint member;
• and
• a cage, which is interposed between the inner spherical surface of the outer joint member and the outer spherical surface of the inner joint member, and is configured to retain the plurality of torque transmission balls,
• wherein the plurality of torque transmitting ball tracks comprise six torque transmitting ball tracks, which are defined as a first track, a second track, a third track, a fourth track, a fifth track, and a sixth track along a circumferential direction,
• wherein an axial offset amount of a curvature center of each of the plurality of track grooves of the outer joint member and an axial offset amount of a curvature center of each of the plurality of track grooves of the inner joint member is set to 0,
• wherein the plurality of track grooves of the outer joint member and the plurality of track grooves of the inner joint member are each inclined with respect to an axis line,
• wherein, in each of the plurality of torque transmitting ball tracks, the one of the plurality of track grooves of the outer joint member and the corresponding one of the plurality of track grooves of the inner joint member, which are opposed to each other, are inclined with respect to the axis line in opposite directions so that inclination angles of the plurality of torque transmitting ball tracks adjacent to each other in the circumferential direction are set to be different from each other, and
• wherein each of the plurality of torque transmitting balls and each of the plurality of track grooves of the inner and outer joint members are held in angular contact with each other at a contact angle of from 30° to 45°.