| 摘要 |
PROBLEM TO BE SOLVED: To provide a screw shaft circulation type ball screw device 1 to circulate a ball group 37 by a screw shaft 34 in which the machining cost is reduced, the workability is enhanced, and the grease lifetime is improved. SOLUTION: In the screw shaft circulation type ball screw device 1 including a screw shaft 34 having a closed loop groove raceway 35 in an outer circumferential surface, a nut member 31 externally fitted to the screw shaft 34 and having a spiral raceway groove 33 in an inner circumferential surface, and a ball group 37 interposed between the raceway groove 35 of the screw shaft 34 and the raceway groove 33 of the nut member 31, a grease storage groove 38 is formed at the position deviated from a contact ellipse of a ball 37 with the inner circumferential surface of the raceway groove 33 of the nut member 31 on a raceway bottom of the raceway groove 33 of the nut member 31. COPYRIGHT: (C)2004,JPO&NCIPI
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