| 摘要 |
PROBLEM TO BE SOLVED: To provide a linear actuator which decreases the backlash and frictional loss and, is embodied in a small and light construction, and performs an accurate feed with a large torque. SOLUTION: A casing 3 supports the periphery of a support member 6 in such a way as capable of moving straight, and the support member 6 moves in a single piece with a ball nut 5. The casing 3 supports rotatably a rotary shaft 9 coupled with the other end of a ball screw 7 to be engaged with the ball nut 5 in its inside, and thereto an ultrasonic motor 11 is fixed. The output shaft 13 of the motor 11 is coupled with the rotary shaft 9, and the support member 6 is coupled with a straight motion output shaft 15. Inside the casing 3, a first groove 21 is formed in the straight motion axial direction of the output shaft 15, and mating with the first groove 21, a second groove 23 is formed at the periphery of the support member 6. The first 21 and second grooves 23 support the first balls 25 in such a way that they roll freely, and are formed by in-oil electric discharge machining.
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