Patent ID: 8336414
Filing Date: 2012-12-25
Classification: F16H,Y10T

Abstract:
1. A roller screw, comprising: a screw shaft having an outer peripheral surface with a roller rolling part spirally formed thereon; a nut having an inner peripheral surface with a loaded roller rolling part spirally formed thereon facing the roller rolling part, and having an unloaded roller return path connecting one end of the loaded roller rolling part with an opposite end thereof; and a plurality of rollers parallel-arranged in a roller circulation path having the unloaded roller return path and a loaded roller rolling path between the roller rolling part and the loaded roller rolling part in such a manner that axis lines of adjacent two of the rollers are held substantially in parallel with each other, wherein the unloaded roller return path has, in a longitudinal direction thereof, at least a twisted part which is twisted such that a central axis of each of the rollers is inclined when the roller moves in the unloaded roller return path, and wherein the twisted part of the unloaded roller return path has a cross section in which each paired side surface corresponding part facing a respective side surface of the roller is convex toward an inside of the unloaded roller return path.