Nsk Corporation

Ryouichi Sato

Soichiro Kato

Hiroki Yamaguchi

Yoshinori Mizumura

Tsutomu Ohkubo

Kazuo Miyaguchi

Nobumitsu Takahashi

Takeshi Nakazawa

Shirouji Yabe

A spacer between adjacent balls of, for example, a ball screw device or a linear motion device has an outer periphery that is concave such that the spacer is elastically deformed to be in substantially circular line contact with the adjacent balls and that a distance therebetween is variable.

Ball screw device and linear motion device

In a ball screw device comprising a screw shaft and a nut which make relative movement to each other through a multiplicity of balls, as well as in a linear motion device comprising an outer member and an inner member which make the relative movements to each other through the multiplicity of balls, a spacer having two concave surfaces facing respectively to balls, is disposed between the balls adjacent to each other. A section of each of the concave surfaces of the spacer is formed of two circular arcs of which central positions deviate from each other to form a Gothic arch. The spacer has such a configuration that the balls adjacent to each other come into contact with outer edges thereof or portions vicinal to the outer edges. The spacer also has such a configuration that the balls adjacent to each other come into contact with at least three or more outer edge portions thereof or portions vicinal to the outer edges. The spacer may have a through-hole formed in a thinnest portion thereof.

In a ball screw device comprising a screw shaft and a nut which make relative movement to each other through a multiplicity of balls, as well as in a linear motion device comprising an outer member and an inner member which make the relative movements to each other through the multiplicity of balls, a spacer having two concave surfaces facing respectively to balls, is disposed between the balls adjacent to each other. A section of each of the concave surfaces of the spacer is formed of two circular arcs of which central positions deviate from each other to from a Gothic. The spacer has such a configuration that the balls adjacent to each other come into contact with outer edges thereof or portions vicinal to the outer edges. The spacer also has such a configuration that the balls adjacent to each other come into contact with at least three or more outer portions thereof or portions vicinal to the outer edges. The spacer may have a through-hole formed in a thinnest portion thereof.

Growing community of inventors

Maebashi, Japan

Ryouichi Sato