MOTOR-DRIVEN POWER STEERING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a motor-driven power steering device allowing easy mounting and removal for replacement (enhanced easiness for the maintenance works) of a nut of a ball-and-screw mechanism on/from the rotary shaft of an electric motor. SOLUTION: A nut 21 of a ball-and-screw mechanism 20 is arranged coaxially with respect to the rotary shaft 11 of a motor 10 installed rotatably relative to a housing 40 and not movable in the axial direction, and the screw shaft 22 of the mechanism 20 serves as a steering shaft 30, and the output from the rotary shaft 11 is transmitted to the steering shaft 30 through the mechanism 20. In this motor-driven power steering device, the nut 21 is coupled with the rotary shaft 11 in such a way as capable of transmitting the torque and not movable in the axial direction using a cylindrical holder 51 fixed to the periphery of the rotary shaft 11 at its one end to accommodate the nut 21 in such a way as capable of setting in and removing in the axial direction and a fixture 52 installed at one end of the holder 51 in such a way as capable of mounting and removing to fix the accommodated nut 21 in such a way as not movable in the axial direction with respect to one end of the rotary shaft 11.