| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw capable of sufficiently securing durability life even in use for applications under a high load in relatively large size such as an electric injection molder and a press. SOLUTION: This ball screw is provided with a screw shaft 52 having a spiral ball rolling groove 55 in an outer circumferential surface, a nut 53 having a spiral ball rolling groove 56 in an inner circumferential surface, and a plurality of balls 54 disposed in a track 57 formed of the ball rolling groove 55 in the screw shaft 52 and the ball rolling groove 56 in the nut 53 facing each other. The lead angleθof the track 57 is set at 15°or less, and a Gothic arc groove is employed for at least either the ball rolling groove 55 in the screw shaft 52 or the ball rolling groove 56 in the nut 53 in the ball screw 51. Where the diameter of the ball 54 is set to be Dw, the radius of curvature of an arc forming the Gothic arc groove is set within a range of 52%Dw or more and 55% Dw or less. Between the balls 54, a spacer 58 is provided. COPYRIGHT: (C)2005,JPO&NCIPI
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