| 摘要 |
PROBLEM TO BE SOLVED: To provide a piece type ball screw which enhances reliability with lower cost by securing positioning accuracy and fixing force of a piece member to a nut. SOLUTION: A piece type ball screw fitted in a piece window 6 bored in a barrel part of the nut 3 and equipped with a piece member 5 including a coupling groove 5a taking a rolling passage as a circumferential route, wherein the piece window 6 is formed in a cross-sectional substantially circular shape, the piece member 5 is correspondingly formed in a cross-sectional circular shape by a sintered alloy molded through the metal injection molding (MIM), an arm 9 is projected to both sides of the barrel part 10 and engaged with a screw groove 3a in the nut 3, a head part 11 extending to an outer diameter side from the barrel part 10 while the piece member 5 is positioned in the nut 3, a pair of guide walls 13 formed of arc-shape peripheral surfaces are arranged in the head part 11 opposite to each other and the outer peripheral surface is formed in a tapered shape gradually decreased in diameter toward the outer diameter side. By so doing, the piece member 5 can be easily fitted into the nut 3, and accurately and easily positioned and fixed. COPYRIGHT: (C)2007,JPO&INPIT
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