US Patent No. 10,458,529


Patent No. 10,458,529
Issue Date October 29, 2019
Title Linear Motion Mechanism, Valve Device, And Steam Turbine
Inventorship Hideki Tonaka, Tokyo (JP)
Naoyuki Nagai, Tokyo (JP)
Yoshitaka Hamamoto, Tokyo (JP)
Makoto Katagake, Hiroshima (JP)

Claim of US Patent No. 10,458,529

1. A linear motion mechanism, comprising:a drive portion;
a screw shaft which is rotationally driven about an axis by the drive portion and in which a first spiral screw groove is formed on an outer peripheral surface;
a nut in which a second spiral screw groove facing the first screw groove is formed on an inner peripheral surface, into which the screw shaft is inserted, and which moves forward or backward relative to the screw shaft in an axial direction, in which an axis of the screw shaft extends, according to a rotation of the screw shaft;
a plurality of load balls which are disposed in a transfer path formed by the first screw groove and the second screw groove and advance while rolling on the transfer path;
a plurality of retainer frames which are disposed between the plurality of load balls and advances on the transfer path along with the load balls; and
a lubricant supply portion which supplies a lubricant to a path surface of the transfer path,
wherein the retainer frame includes
a retainer main body portion in which recessed surfaces, on which outer peripheral ends are in contact with the adjacent load balls, are formed on both sides in an advancement direction and which is formed to be smaller than the load ball when viewed in the advancement direction, and
a lubricant contact portion which protrudes from the outer peripheral end of the recessed surface of the retainer main body portion toward the path surface side of the transfer path and is formed to come into contact with the lubricant which is supplied to the path surface of the transfer path, and
wherein the lubricant contact portion is formed such that a cross-sectional shape orthogonal to the advancement direction partially protrudes toward the path surface of the transfer path more than the load ball.