Ntn Corporation

Yoshimasa Ushioda

Masaru Komatsu

Hisaaki Kura

Kenji Terada

Akio Sakaguchi

Shigeyoshi Ishiguro

Katsuhiro Suzuki

Tetsuro Kadota

Kazuhiro Muramatsu

Yukio Asahara

Hiroki Terada

Hiroyuki Matsuoka

Hiroki Ooe

A steel ball rolling configuration and a constant velocity universal joint have a superior oil retention effect between a surface of a steel ball and a partner rolling surface, and can form a thick oil film, improve lubrication, and extend life of the steel ball. The constant velocity universal joint includes a rolling surface and a steel ball that is lubricated by grease and rolls over the rolling surface. A surface roughness of the steel ball is roughened to become more similar to a surface roughness of a partner rolling surface. Numerous miniscule recesses roughly tens of micrometers in size are randomly disposed on the surface of the steel ball.

Steel ball rolling configuration and constant velocity universal joint

A perpendicular distance (PCR,) between a centerline (L,) including the center (O,) of the outer circumference surface (,) of an outer roller (,), orthogonal to axis Z of a trunnion (,) and a joint center O is shifted by &Dgr;h (&equals;PCR,&minus;PCR,) from a perpendicular distance (PCR,) between a centerline (L,) including the center (O,) of the outer circumference surface (,) of an inner roller (,), orthogonal to axis Z of a trunnion (,) and a joint center O. Under the most favorable conditions, PCR,is shifted by an optimal amount of &Dgr;H from PCR,toward the proximal end of the trunnion, and the position of contact (S) between the inner circumference surface (,) of the outer roller,and the outer circumference surface (,) of the inner roller (,) is located on the centerline (L,) (on PCR,) of the outer circumference surface (,) of the outer roller (,).

Constant velocity universal joint

An inner roller is rotatably fitted on a trunnion of a tripod member through a plurality of needle rollers and held in position against slipping off the trunnion by a slip-off preventing ring and a stopper ring mounted on the distal end of the trunnion.

Homokinetic universal joint having decreased induced thrust

Growing community of inventors

Iwata, Japan

Yoshimasa Ushioda