ELECTRIC POWER STEERING DEVICE

摘要

PROBLEM TO BE SOLVED: To stabilize a torque limit function by interposing a torque limit member slipping by prescribed torque between a sleeve and a rotor and freely rotatably supporting both ends of the sleeve on a housing. SOLUTION: A torque limit member 53 is press-fitted into both of a sleeve 52 and a rotor 32 via prescribed elasticity of a spring or the like and torque of an electric motor 30 is transmitted by elastic force of the press-fitting part by torque to be normally used in an electric power steering device. For impact torque beyond elastic force of the press-fitting part caused by suddenly stopping stroke of a rack shaft 16 because tires run into curbstones during a steering and affecting large impact on a screw groove of a ball screw device 50 by inertia force of the electric motor 30 rotating at high speed by a ratio of lead of the ball screw device 50, the rotor 32 functions to slide on the sleeve 52 and to prevent transmission of torque of the electric motor 30 and damage of the screw groove of the ball screw device 50 can be prevented.