摘要 |
An electric actuator which is used for e.g. an arm of an industrial robot includes a composite shaft having a ball screw groove and a ball spline groove, a hollow motor through which the composite shaft extends, a ball screw nut fitted threadedly about the composite shaft and secured to a motor shaft, and a ball spline nut fitted about the composite shaft and secured to a motor housing. The ball spline nut, ball screw nut, and motor are arranged in the order mentioned as viewed from an attachment for a moving body which is provided at one end of the composite shaft. An angular-contact bearing which supports the motor shaft rotatably is situated closer to the ball screw nut than the motor is.
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