Ntn Corporation

Kiyohiro Itou

Keisuke Sone

Kazuhiko Yoshida

Hirokazu Ooba

An eight-ball fixed type constant velocity universal joint of an undercut free type is capable of increasing a torque capacity at high operating angles while securing durability at low operating angles. When a distance between a center of a track groove and a center of a ball is denoted by Rt, and when an axial distance between the center of the track groove and a joint center plane is denoted by F, a ratio R1 of F to Rt is set to fall within a range of 0.061&#x2266;R1&#x2266;0.087. When a radial offset amount, which is a distance between the center of the track groove and a joint center axial line is denoted by fr, a ratio R3 of fr to Rt is set to fall within a range of 0.07&#x2266;R3&#x2266;0.19. When an effective cured-layer depth with Hv 513 is denoted by Di and the diameter of the ball is denoted by d, a bottom surface of a track groove of an inner joint member includes a cured layer with an effective cured-layer depth ratio Di/d of at least 0.111 or more.

Fixed type constant velocity universal joint

A fixed type constant velocity universal joint of an eight-ball undercut-free type has improved torque capacity at high operating angle while ensuring durability at low operating angle. Centers of a track groove () of an outer joint member and a track groove () of an inner joint member are respectively separated from a center plane (P) toward axially different sides, and are offset away from a joint center axis (X) to a radially opposite side relative to grooves (). When Rt represents a distance between a center of a ball () and the center of groove (), and F represents an axial distance between plane (P) and the center of groove (), a ratio Rbetween F and Rt is 0.061&#x2266;R&#x2266;0.087. When fr represents a radial offset amount as a distance between axis (X) and the center of groove (), a ratio Rbetween fr and Rt is 0.07&#x2266;R&#x2266;0.19.

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Iwata, Japan

Kiyohiro Itou