| 摘要 |
PROBLEM TO BE SOLVED: To provide a lower-cost automobile ball screw with a screw stem having higher toughness resulting in less breakage. SOLUTION: The ball screw 1 to be used for an actuator such as an automobile transmission comprises a screw stem 2, a nut 3, and a ball 6 laid between screw grooves 4, 5 formed in the opposite faces of the screw stem 2 and the nut 3. To the screw stem 2, high frequency quenching is applied only for an axial range L where the ball 6 rolls in use and for a coupling fitting portion 2d and no treatment is applied for other portions. A remaining austenite amount is 1-10% for the high frequency quenched portion of the screw stem 2 and zero for the non-quenched portions. COPYRIGHT: (C)2006,JPO&NCIPI
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