RACK/PINION TYPE ELECTRIC POWER STEERING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an electric power steering device capable of preventing a generation of a local abrasion on a ball track surface in a ball screw shaft and a ball nut. SOLUTION: A ball nut 63 is thread-engaged with a ball screw shaft 61 integrally formed on a rack engaged with a pinion through a circulation ball 62. A motor 8 for imparting a steering auxiliary force which rotates and drives the ball nut 63 has a stator 8a fixed to a housing 31 side covering the rack and a rotor 8b which is rotatably supported to the housing 31 side and to which the rack is inserted. A grease-retaining space 90 has an opening opposed to an outer periphery of the ball screw shaft 61 is formed on the housing 31 and at least one of members positioned in the housing 31.