| 主权项 |
1. A fixed type constant velocity universal joint, comprising:
an outer joint member having a spherical inner peripheral surface in which a plurality of track grooves are formed so as to extend in an axial direction of the outer joint member,
the outer joint member having an opening side and an interior side spaced apart from each other in the axial direction; an inner joint member having a spherical outer peripheral surface in which a plurality of track grooves are formed so as to be paired with the plurality of track grooves of the outer joint member; a plurality of balls for transmitting torque,
the plurality of balls being interposed between the plurality of track grooves of the outer joint member and the plurality of track grooves of the inner joint member; and a cage comprising pockets for holding the plurality of balls,
the cage having a spherical outer peripheral surface, which is fitted to the spherical inner peripheral surface of the outer joint member, and a spherical inner peripheral surface, which is fitted to the spherical outer peripheral surface of the inner joint member, wherein the plurality of track grooves of the outer joint member comprise:
first track groove portions (7a) positioned on the interior side; andsecond track groove portions (7b) positioned on the opening side, wherein the first track groove portions (7a) each have an arc-shaped ball raceway center line (Xa) having a curvature center that is prevented from being offset in the axial direction with respect to a joint center (O), wherein planes (M) each comprising at least the arc-shaped ball raceway center line (Xa) and the joint center (O) are inclined with respect to a joint axial line (N-N) with their inclination directions alternately opposite to each other in the first track groove portions (7a) that are adjacent to each other in a peripheral direction of the outer joint member, wherein the second track groove portions (7b) each have an arc-shaped ball raceway center line (Xb) having a curvature center that is offset to a radially outer side with respect to the arc-shaped ball raceway center line (Xa) of corresponding one of the first track groove portions (7a), wherein an end portion (A) of the arc-shaped ball raceway center line (Xa) of each of the first track groove portions (7a) is positioned on the opening side with respect to the joint center (O), wherein a position of the end portion (A) occupies at least 60% of an effective track length on the opening side with respect to the joint center (O), wherein the arc-shaped ball raceway center line (Xb) of each of the second track groove portions (7b) is connected to the end portion (A), and wherein a ball raceway center line (Y) of each of the plurality of track grooves of the inner joint member is formed so as to be mirror-image symmetrical with a ball raceway center line (X) of corresponding one of the plurality of paired track grooves of the outer joint member with respect to a plane (P) comprising the joint center (O) at an operating angle of 0°. |
