| 摘要 |
PROBLEM TO BE SOLVED: To provide an internal circulation ball lead screw having a small nut diameter, simple manufacturing processes and favorable smoothness during the reverse motion of balls. SOLUTION: This sort of a backbone type internal circulation ball screw unit comprises a lead screw unit, a nut 2, a plurality of the balls 3, and a ball circulator having a S-shaped ball groove 4d. The circulator is mounted in the linear groove of the nut 2, and the linear groove has a bottom as an arch-curved face 2b. The passage bottom of the nut 2 has a cut-off portion smoothly transferred toward the arch-curved face 2b. The inside of the circulator having the ball groove 4d is directed to the lead screw unit, while the ball groove 4d is directed at its opening side to the arch-curved face 2b of the linear groove to form a ball return passage in cooperation with the arch-curved face 2b. COPYRIGHT: (C)2009,JPO&INPIT
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