| 摘要 |
PROBLEM TO BE SOLVED: To improve a service life of a ball screw device by restraining quantity of foreign matter entering between a rolling surface and a ball by preventing production of metal powder, etc. due to contact of the ball on an inner surface of a circulating tube. SOLUTION: This ball screw device is furnished with a screw stem 3 having a spiral thread groove 2 on an outer peripheral surface, a nut 6 having a thread groove 4 to correspond to the thread groove 2 on an outer peripheral surface and to be fitted on the screw stem 3 with a play, a large number of the balls 5 loaded on a load truck formed between the both thread grooves 2, 4 free to roll and the circulation tube 8 provided on the nut 6 to infinitely circulate the balls 5 rolling on the load truck, and inner surface roughness of the circulating tube 8 is made less than 0.2μmRa in arithmetical mean roughness. COPYRIGHT: (C)2004,JPO
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