Nsk Corporation

Ken Namimatsu

Toshikazu Yabe

Toru Tsukada

Kazuo Miyaguchi

Nobuhide Kurachi

Osamu Ideta

Manabu Matsuura

A lubricating apparatus for a ball screw which can sufficiently lubricate even in a high load usage is disposed between a ball nut and a screw shaft, and a polymer member containing a lubricant being mainly in slidable contact with an outer diameter portion of the screw shaft is mounted to at least any one of both ends of the ball nut and a space including a ball not-passing space in an inner portion of the ball nut. The polymer member prevents the lubricant attached to the thread groove of the screw shaft from being scraped off during oscillations of the screw shaft, such that the lubricant attached to the thread groove can be efficiently maintained.

Lubricating apparatus for ball screw

A ball screw comprising a screw shaft, a ball screw nut, a plurality of balls contained in the ball screw nut which is in threadable engagement with the shaft so that it is capable of relative movement in the linear axial direction as guided by the rolling of the balls, and a lubricant-containing polymer member that is installed in the ball screw nut in contact with the balls or in slidable contact with screw grooves in the screw shaft. The lubricant seeps out of the polymer member slowly and is supplied not only to the balls but also to the screw grooves, so that it maintains the desired lubricating effect in a consistent and automatic way over an extended period of time.

Ball screw lubricated with oil-containing polymer

Nut 2 in threadable engagement with the screw shaft 1 of a feed screw apparatus is fitted with a lubricant supply device 30 which also serves as a seal. This device is made of a lubricant-containing rubber or synthetic resin and has a plurality or projections 31 in the inner surface that contact the outer circumference of the screw shaft 1. The lubricant in said rubber or synthetic resin slowly seeps out unoxidized for an extended period of time to perform effective lubrication.

A ball screw device is designed such that a load axially applied to a ball nut is uniformly supported by balls of all ball screw groove portions. The design is such that a gap along a load acting line between a ball and a ball screw groove portion farther from an attachment portion of the ball nut is smaller than a gap between a ball and a ball screw groove portion closer to the attachment portion, by an amount corresponding to an elastic deformation caused in the corresponding screw groove portion of the ball nut by a load acting on the ball nut.

Ball screw device

In a self-lubrication linear guide apparatus including a guide rail, a slider and a plurality of rolling elements, the apparatus further includes a plurality of lubricant-containing polymer spacer balls which are interposed between the rolling elements inside the slider. A lubricant gradually exudes from the lubricant-containing polymer spacer balls as time elapses to be automatically supplied to the rolling elements, so that satisfactory self lubrication can be achieved over a long period of time.

Linear guide apparatus with lubricant-containing polymer spacer balls

In a thin-wall type ball nut of a light-weight type ball screw having a trunnion structure in which a pair of trunnion shafts are extended from the ball nut in the opposite directions; a pair of ribs for increasing the wall thickness of the ball nut are formed on both side surfaces of the ball nut in such a manner that the ribs are extended from the base portions of the trunnion shafts along the axis of the ball nut, so as to increase the rigidity of the portions of the nut body which are liable to be deformed, thereby to prevent the ball nut from deformation.

Growing community of inventors

Gunma, Japan

Ken Namimatsu