Slide-type constant velocity universal joint
A light and compact slide-type constant velocity universal joint has a maximum operating angle of 30° or more through optimization of a ball contact angle relative to ball grooves, a ball contact ratio, and a cage offset amount. In the slide-type constant velocity universal joint, a ratio of ball diameter to outer ring outer diameter is 0.21 to 0.25, a ratio of ball pitch diameter to outer ring outer diameter is 0.64 to 0.68, a contact angle of the ball groove is 30° to 35°, a contact ratio of the ball groove is 1.02 to 1.08, and a ratio of cage offset amount to ball pitch diameter is 0.07 to 0.09.
1. A slide-type constant velocity universal joint for use on an inboard side of a drive shaft of an automobile, the slide-type constant velocity universal joint comprising:
an outer ring in which six linear ball grooves are formed on a cylindrical inner circumferential surface in an axial direction;
an inner ring on which six linear ball grooves are formed on a spherical outer circumferential surface in the axial direction and a connecting hole for connecting a shaft is formed in a center section;
six torque transmission balls disposed on ball tracks, each of the ball tracks being formed by one of the ball grooves on the outer ring and one of the ball grooves on the inner ring; and
a cage having pockets accommodating the torque transmission balls,
wherein the cage has a convex spherical outer circumferential surface that is in contact with and guided by the inner circumferential surface of the outer ring, and a concave spherical inner circumferential surface that is in contact with and guided by the outer circumferential surface of the inner ring,
wherein a spherical surface center of the outer circumferential surface and a spherical surface center of the inner circumferential surface are respectively offset to opposite sides of a joint center in the axial direction by an equal distance, the distance constituting a cage offset amount,
wherein a ratio of ball diameter to outer ring outer diameter is 0.21 to 0.25,
wherein a ratio of ball pitch diameter to outer ring outer diameter is 0.64 to 0.68,
wherein a contact angle of the ball grooves is 30° to 35°,
wherein a contact ratio of the ball grooves is 1.02 to 1.08, the contact ratio being a ratio of groove radius of curvature to ball radius,
wherein a ratio of the cage offset amount to ball pitch diameter is 0.07 to 0.09, and
wherein a maximum operating angle of the slide-type constant velocity universal joint is at least 30°.
2. A drive shaft comprising the slide-type constant velocity universal joint according to claim 1 on an inboard side of the drive shaft, and further comprising a fixed-constant velocity universal joint having eight torque transmission balls on an outboard side of the drive shaft.