| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw with a long service life, especially the ball screw with the long service life suitably used in a machine tool applying a high load to a fixed direction. SOLUTION: The ball screw includes a screw shaft 2 having a spiral ball rolling groove 1a on an outer peripheral surface, a nut 3 having a spiral ball rolling groove 1b on an inner peripheral surface, and a plurality of balls 5 arranged in a raceway 1 formed by the ball rolling groove 1a of the screw shaft 2 and the ball rolling groove 1b of the nut 3 facing with each other. A gothic arc groove including two arcs is used for the ball rolling groove 1a of the screw shaft 2 and the ball rolling groove 1b of the nut 3. Of the two arcs included in the gothic arc groove, a curvature of the one arc to which the main load is applied is larger than the other arc to which the main load is not applied when the main load is applied to the fixed direction along an axial direction of the screw shaft 2. COPYRIGHT: (C)2010,JPO&INPIT
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