Thk Co., Ltd.

Kentarou Nishimura

Hiroshi Niwa

Akimasa Yoshida

Yasuyuki Abe

Kiyomi Tamura

Takeki Shirai

Takahiro Kawaguchi

Tadashi Hirokawa

Osamu Maruyama

Shino Kimura

The invention relates to a ball screw device in which a screw shaft and a nut member are threadedly engaged with each other through a number of balls. In such a ball screw device, an inner surface of a cover plate contacting an end surface of a nut main body is provided with a projecting return piece adapted to be fit-engaged with a recess cut in an inner peripheral surface of the nut main body, the return piece being provided with a scoop portion for dislodging the balls from the ball rolling groove of the screw shaft and a direction switching passage for guiding the dislodged balls to the entrance of a ball return hole. The projecting return piece is divided into a first piece formed integral with the cover plate and a second piece fixed to the first piece by a curved plane including the center line of the direction switching passage.

Ball screw device

There is provided a rolling element spacer used in a rolling guide device having an endless circulation passage of balls, arranged alternately with many balls in the endless circulation passage, and circulating together with the balls in the endless circulation passage. It has a pair of ball holding seats each of which is formed in a concave spherical face form nearly approximating a spherical face of the ball and sliding-contacts with the ball and, around each ball holding seat, there is formed an annular dropout prevention portion protruding in a ball arranging direction than an edge portion of the ball holding seat and kept in non-contact with respect to the ball seated on the ball holding seat.

Rolling element spacer in rolling guide device

A roller retainer encloses an outer periphery of the roller situated on a diagonal when the roller is viewed from the side surface thereof. Whether the rollers are arranged in a parallel manner or in a cross manner, the roller retainer is able to keep a constant position and thus the disposition of the roller retainer is free from the influence of the direction the roller . Also, since the roller retainer restricts a corner portion of the roller , the roller is difficult to slip off the roller retainer and thus the roller can be restricted positively, thereby being able to control the skew of the roller

Roller retainer, roller screw using roller retainer and rolling guide apparatus using roller retainer

The present invention provides rolling element spacers used in a rolling guide unit provided with an endless circulating passage for balls; arranged with plural balls alternately therewith in the endless circulating passage; and circulated with these balls in the endless circulating passage. Each of the rolling element spacers has a pair of retaining seats which the balls contact, and is formed so that, on a ball cutting plane perpendicular to the center of rotation of each ball, each retaining seat and a relative ball contact each other at only the two portions of the retaining seat that are in the vicinity of both ends thereof.

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Tokyo, Japan

Kentarou Nishimura