| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw mechanism preventing erroneous combination of a ball in assembly. SOLUTION: A groove part 2B in which the ball 3 does not roll is a simple circular arc shape including a radius of curvature R2 (<Sϕ1/2+Δ) smaller than quantity of a radius (Sϕ1/2) of the ball 3 from which a clearance quantity in the radial directionΔis deducted in a cross-section shape orthogonal to an axis of a female screw groove 2a, or BCD (BCDn') of the ball rolling along the groove part 2B in which the ball does not roll is smaller than BCDs of the ball 3 rolling along a male screw groove 1a as seen in the axial direction of a nut 2. The ball thereby cannot physically intrude between the groove part 2B not rolling and the male screw groove 1a, and erroneous combination of the ball 3 is prevented and locking of the ball screw mechanism is also prevented. COPYRIGHT: (C)2009,JPO&INPIT
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