Patent attributes
A flange member 20, which is formed as a separate body from a motor shaft 6, is screwed to an end 6a of the motor shaft 6. The flange member 20 functions as a flange 19 of the motor shaft 6. A flange 18, which is formed at an end 13a of a ball screw nut 13, is fastened to the flange 19 of the motor shaft 6. This couples the ball screw nut 13 to the motor shaft 6. A coupling member 27 is arranged in the joint portion between the ball screw nut 13 and the motor shaft 6. The coupling member 27 is formed by a tubular portion 28 and a plate flange 29, which extends radially outward from the outer circumferential surface of an end of the tubular portion 28. The tubular portion 28 of the coupling member 27 is fixed to the motor shaft 6, and the plate flange 29 is fixed to the flange member 20.
