Ntn Corporation

Hiroyasu Hirukawa

Kenta Yamazaki

Teruaki Fujio

Kisao Yamazaki

A fixed type constant velocity universal joint of a track groove crossing type has track grooves of an inner joint member formed so as to be mirror-image symmetrical with the paired track grooves of an outer joint member with respect to a joint center plane at an operating angle of 0&#xb0;. The track grooves of both the joint members each have a length corresponding to a maximum operating angle required for a rear-wheel drive shaft. Further, each axial clearance between the inner joint member and the cage is set larger than an axial clearance formed by a ball track clearance between each of balls and each track groove.

Fixed-type constant velocity universal joint

Six track grooves formed in a spherical inner peripheral surface of an outer joint member are each formed into an arc shape having a curvature center at a joint center. The track grooves are inclined in a circumferential direction of the outer joint member with respect to a joint axial line, and are adjacent to each other in the circumferential direction with their inclination directions opposite to each other. Six track grooves formed in a spherical outer peripheral surface of an inner joint member are formed so as to be mirror-image symmetrical with the track grooves paired therewith of the outer joint member with respect to a joint center plane at an operating angle of 0&#xb0;. An inclination angle of each of the track grooves of the outer joint member with respect to the joint axial line is set to 8&#xb0; or more and 16&#xb0; or less.

Fixed type constant velocity universal joint

A fixed type constant velocity universal joint of a track groove crossing type has track grooves of an inner joint member formed to be mirror-image symmetrical with paired track grooves of an outer joint member with respect to a joint center plane at an operating angle of 0&#xb0;. The track grooves of both the joint members each have a length corresponding to a maximum operating angle (&#x3b8;max) required for a propeller shaft, and surface treatment is performed, for example, on a defined surface of each of the track grooves of the outer joint member so as to reduce frictional resistance (sliding resistance) against balls.

A fixed type constant velocity universal joint has an outer joint member including first track groove portions and second track groove portions. Each of the first track groove portions includes an arc part having a curvature center that is not offset in an axial direction with respect to a joint center. The first track groove portions are inclined in a peripheral direction of the outer joint member with respect to a joint axial line and adjacent to each other in the peripheral direction with inclination directions opposite to each other. Each of the second track groove portions has a different shape than the first track groove portions. Each of the first track groove portions and each of the second track groove portions are connected to each other at a position on an opening side with respect to the joint center.

Track grooves of an outer joint member include first and second track groove portions. Each of the first track groove portions is formed into an arc shape having a curvature center at a position offset to an opening side with respect to a joint center. The first track groove portions are inclined in a peripheral direction of the outer joint member with respect to a joint axial line and adjacent to each other in the peripheral direction with their inclination directions opposite to each other. Each of the second track groove portions includes a linear part and is connected to the each of the first track groove portions at a position on the opening side with respect to the joint center. Track grooves of inner and outer joint members are formed to be mirror-image symmetrical with respect to a joint center plane at an operating angle of 0&#xb0;.

Fixed type constant-velocity universal joint

Provided is a fixed type constant velocity universal joint, in which: each of first track groove portions positioned on an interior side of an outer joint member includes an arc part having a curvature center that is positioned without being offset in an axial direction with respect to a joint center; the first track groove portions are inclined in a peripheral direction with respect to a joint axial line (N-N) and adjacent to each other in the peripheral direction with their inclination directions opposite to each other; each of second track groove portions positioned on an opening side is formed into a different shape from a shape of the each of the first track groove portions so as to increase an effective track length at a maximum operating angle; the each of the first track groove portions and the each of the second track groove portions are connected to each other at a position on the opening side with respect to the joint center; each of track grooves of an inner joint member is formed so as to be mirror-image symmetrical with corresponding one of paired track grooves of the outer joint member with respect to a plane including the joint center and being perpendicular to the joint axial line at an operating angle of 0&#xb0;; and an axial clearance between the inner joint member and a cage is set to be larger than an axial clearance corresponding to a clearance between each of balls and each of the track grooves.

In a fixed type constant velocity universal joint, track grooves of an outer joint member include first track groove portions positioned on an interior side and second track groove portions positioned on an opening side. The first track groove portions each have an arc-shaped ball raceway center line having a curvature center that is prevented from being offset in an axial direction of the outer joint member with respect to a joint center. Planes each including at least the ball raceway center line and the joint center are inclined with respect to a joint axial line with their inclination directions alternately opposite to each other in the first track groove portions that are adjacent to each other in a peripheral direction of the outer joint member.

In a fixed type constant velocity universal joint, track grooves of an outer joint member include first and second track groove portions positioned on interior and open sides, respectively. Each of the first track groove portions includes an arc-shaped ball raceway center line having a curvature center prevented from being offset in an axial direction of the outer joint member with respect to a joint center. Planes each including at least the ball raceway center line and the joint center are inclined with respect to a joint axial line with their inclination directions opposite to each other in the first track groove portions, which are adjacent to each other in a peripheral direction of the outer joint member. Each of the second track groove portions includes a ball raceway center line having a straight part when being projected onto corresponding one of the planes.

Track grooves of an outer joint member include first and second track groove portions positioned on interior and opening sides, respectively. Each first track groove portion has an arc shape with a curvature center at a position offset to the opening side with respect to a joint center. The first track groove portions are inclined in a peripheral direction of the outer joint member with respect to a joint axial line and adjacent to each other in the peripheral direction with their inclination directions opposite to each other. Each second track groove portion has a shape that is different than each of the first track groove portions so as to increase an effective track length at a maximum operating angle. The second track groove portions are connected to the first track groove portions at a position on the opening side with respect to the joint center.

An outer joint member has first and second track groove portions located respectively on depth and opening sides. The first track groove portions each have a circular-arc ball-raceway center line having a curvature center that is not offset in an axial direction with respect to a joint center. The second track groove portions each have a ball-raceway center line including a straight part to increase an effective track length at a maximum operating angle. Track grooves of an inner joint member each have a ball-raceway center line that is mirror-image symmetrical with a ball-raceway center line of the paired track groove of the outer joint member with respect to a plane passing through the joint center at an operating angle of 0&#xb0;.

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Shizuoka, Japan

Hiroyasu Hirukawa