A boot band includes a band body, which is obtained by forming a band-plate-like member into a ring shape, and a lever, which is obtained by forming a strip-like member into an arc shape, and is provided on a joined portion of the band body. The boot band fastens a boot for a constant velocity universal joint, which is arranged on an inner side of the band body, by reducing the band body in diameter such that the lever is turned over using an end portion of the lever as a fulcrum and then superposed on the band body, thereby reducing the band body in diameter. The lever includes two chamfered portions formed in a fulcrum-side region of the end portion of the lever along a thickness direction of the lever.

A constant-velocity universal joint including a generally cup-shaped outer joint member and an inner joint member that define first and second groove portions. A pinch angle by which a ball is pinched in the first groove portion is open toward an opening of the outer joint member. A pinch angle by which the ball is pinched in the second groove is open toward a bottom of the outer joint member. An absolute value of the pinch angle in a larger-pinch-angle groove portion that is one of the first and second groove portions, is larger than an absolute value of the pinch angle in a smaller-pinch-angle groove portion that is the other of the first and second groove portions in a reference state. A radial clearance in the smaller-pinch-angle groove portion is larger than a radial clearance in the larger-pinch-angle groove portion when torque is not transmitted in the reference state.

A constant-velocity universal joint including a generally cup-shaped outer joint member and an inner joint member that define first and second groove portions. A pinch angle by which a ball is pinched in the first groove portion is open toward an opening of the outer joint member. A pinch angle by which the ball is pinched in the second groove is open toward a bottom of the outer joint member. An absolute value of the pinch angle in a larger-pinch-angle groove portion that is one of the first and second groove portions, is larger than an absolute value of the pinch angle in a smaller-pinch-angle groove portion that is the other of the first and second groove portions in a reference state. A radial clearance in the smaller-pinch-angle groove portion is larger than a radial clearance in the larger-pinch-angle groove portion when torque is not transmitted in the reference state.

A constant-velocity universal joint including a generally cup-shaped outer joint member and an inner joint member that cooperate with each other to define first and second groove portions. A pinch angle by which a ball is pinched in the first groove portion is open toward an opening end of the outer joint member. A pinch angle by which the ball is pinched in the second groove is open toward a bottom wall of the outer joint member. An absolute value of the pinch angle in the first groove portion is larger than an absolute value of the pinch angle in the second groove portion in a reference state in which centerlines of the outer joint member and the inner joint member lie in a straight line.

A constant-velocity universal joint including a generally cup-shaped outer joint member and an inner joint member that cooperate with each other to define first and second groove portions. A pinch angle by which a ball is pinched in the first groove portion is open toward an opening end of the outer joint member. A pinch angle by which the ball is pinched in the second groove is open toward a bottom wall of the outer joint member. An absolute value of the pinch angle in the first groove portion is larger than an absolute value of the pinch angle in the second groove portion in a reference state in which centerlines of the outer joint member and the inner joint member lie in a straight line.

A universal joint (U-joint) assembly transmits torque from a drive component to a driven component across an articulating joint. The U-joint assembly includes male and female U-joint members, a central ball joint, and a retaining device configured to secure the assembly in an assembled configuration. The female U-joint member includes a cavity extending into a receptacle end thereof. The cavity terminates in a circular receptacle and includes four flat surfaces extending longitudinally therefrom at 90-degree intervals. The male U-joint member has a drive end with four multi-angled surfaces extending longitudinally from the drive end at 90-degree intervals about a periphery of the drive end. When in an assembled configuration, each of the multi-angled surfaces of the drive end of the male U-joint member opposes a corresponding one of the four flat surfaces of cavity of the female U-joint member. Other embodiments are also disclosed.

A universal joint (U-joint) assembly transmits torque from a drive component to a driven component across an articulating joint. The U-joint assembly includes male and female U-joint members, a central ball joint, and a retaining device configured to secure the assembly in an assembled configuration. The female U-joint member includes a cavity extending into a receptacle end thereof. The cavity terminates in a circular receptacle and includes four flat surfaces extending longitudinally therefrom at 90-degree intervals. The male U-joint member has a drive end with four multi-angled surfaces extending longitudinally from the drive end at 90-degree intervals about a periphery of the drive end. When in an assembled configuration, each of the multi-angled surfaces of the drive end of the male U-joint member opposes a corresponding one of the four flat surfaces of cavity of the female U-joint member. Other embodiments are also disclosed.

A double-offset plunging type constant velocity universal joint includes inner and outer joint members each having six linear track grooves extending along an axial direction. The inner joint member has a coupling hole at a center portion thereof for coupling a shaft. Six torque transmission balls retained by a cage are incorporated between the linear track grooves of the inner and outer joint members. A ratio T.sub.CAGE/D.sub.BALL of a minimum thickness (T.sub.CAGE) of the cage to a diameter of the torque transmission ball (D.sub.BALL) is from 0.225 to 0.245, wherein a ratio D.sub.BALL/D.sub.S of a diameter (D.sub.BALL) of the torque transmission ball to a spline large diameter (D.sub.S) of the coupling hole of the inner joint member is from 0.79 to 0.85, and wherein a ball contact ratio () of the torque transmission ball is from 1.08 to 1.12.

A double-offset plunging type constant velocity universal joint includes inner and outer joint members each having six linear track grooves extending along an axial direction. The inner joint member has a coupling hole at a center portion thereof for coupling a shaft. Six torque transmission balls retained by a cage are incorporated between the linear track grooves of the inner and outer joint members. A ratio T.sub.CAGE/D.sub.BALL of a minimum thickness (T.sub.CAGE) of the cage to a diameter of the torque transmission ball (D.sub.BALL) is from 0.225 to 0.245, wherein a ratio D.sub.BALL/D.sub.S of a diameter (D.sub.BALL) of the torque transmission ball to a spline large diameter (D.sub.S) of the coupling hole of the inner joint member is from 0.79 to 0.85, and wherein a ball contact ratio () of the torque transmission ball is from 1.08 to 1.12.

A constant velocity joint assembly includes an outer joint member defining a first longitudinal axis and including a closed end, an open end, a first set of outer tracks extending at least partially between the closed end and the open end, and a second set of outer tracks extending at least partially between the closed end and the open end. The assembly also includes an inner joint member defining a second longitudinal axis coaxial with the first longitudinal axis and including a first set of inner tracks and a second set of inner tracks, the inner joint including an attachment feature to receive a driveshaft. A path followed by the center of a ball in the first set of tracks is constrained by an outer race track path and an inner race track path, the outer race track path being a piecewise continuous function.