Roller screw

A roller screw comprising:

• a screw shaft having a spiral roller rolling surface formed on an outer peripheral surface of the screw shaft;
• a nut having a loaded roller rolling surface formed in an inner peripheral surface of the nut, facing the roller rolling surface of the screw shaft;
• a circulation member provided on the nut and having an unloaded return path connecting one end of the loaded roller rolling surface of the nut to an opposite end thereof;
• a plurality of rollers arranged in a loaded roller rolling path between the roller rolling surface of the screw shaft and the loaded roller rolling surface of the nut and in the unloaded return path of the circulation member;
• and
• a scooping portion, provided in the circulation member, for scooping the rollers moving in the loaded roller rolling path up into the unloaded return path, the scooping portion having a pair of diagonal corresponding parts which jut toward the screw shaft from an edge of a continuous path of V shaped cross section connected to the loaded roller rolling surface of the nut and which correspond to diagonal parts of a rectangular side surface of each of the rollers, and a width between the diagonal corresponding parts tapering as the pair of diagonal corresponding parts are deeper in the unloaded return path in such a manner that the unloaded return path formed by the diagonal corresponding parts and the continuous path has a rectangular-shaped cross section in accordance with a deepness of the unloaded return path.

A roller screw, comprising:

• a screw shaft having a spiral roller rolling surface formed on an outer peripheral surface of the screw shaft;
• a nut having a loaded roller rolling surface formed in an inner peripheral surface of the nut, facing the roller rolling surface of the screw shaft;
• a circulation member provided on the nut and having an unloaded return path connecting one end of the loaded roller rolling surface of the nut to an opposite end thereof;
• a plurality of rollers arranged in a loaded roller rolling path between the roller rolling surface of the screw shaft and the loaded roller rolling surface of the nut and in the unloaded return path of the circulation member;
• and
• a scooping path provided in the unloaded return path circulation member and having a scooping portion for scooping the rollers moving in the loaded roller rolling path up into the unloaded return path, a center line of the scooping path being outside of a tangential direction of the loaded roller rolling path when seen in an axial direction of the nut.