Thk Co., Ltd.

Hironori Shoji

Hideki Fujii

Hidekazu Michioka

Takeki Shirai

Katsuya Iida

Hiroshi Niwa

Satoru Nagai

Toshiaki Kadono

Yasuyuki Abe

Yoshitaka Takahashi

a ball spline enabling easy machining of a spline shaft by drawing and manufacturable at low cost. The ball spline includes a spline shaft in which multiple lines of ball rolling faces are formed along the longitudinal direction; and a spline nut having a hollow hole for inserting the spline shaft therein, having load rolling faces opposed to the ball rolling faces of the spline shaft. Multiple lines of torque transmission grooves along the longitudinal direction are formed at equal intervals around the spline shaft, and the ball rolling faces are formed on the lateral both sides of these torque transmission grooves. Further, a distance between a pair of ball rows rolling on both sides of the land parts of the spline shaft is set larger than a distance between a pair of ball rows rolling on both sides of the torque transmission grooves.

Ball spline

A circulation member of a ball screw for circulating a ball rolling on a spiral ball rolling groove formed on a screw shaft. The circulation member includes a central portion and a pair of leg portions disposed at both ends of the central portion so as to extend therefrom, the leg portions having inner peripheries having center lines inclined in directions different from each other with respect to a center line of an inner periphery of said central portion. The leg portions also have outer peripheries having center lines being parallel to each other and have thicknesses, different in circumferential directions thereof, at cross sections in directions normal to center lines of the outer peripheries of the respective leg portions.

Circulation member of ball screw and ball screw using same

Growing community of inventors

Tokyo, Japan

Hironori Shoji