Patent ID: 6439339
Filing Date: 2002-08-27
Classification: B62D

Abstract:
In an electronic power steering apparatus for a vehicle which includes a motor housing provided at an intermediate portion of a pinion housing having a rack bar therein, a ball nut inserted into an inner end portion of a motor shaft which is rotatable in an interior of the motor housing and moves the rack bar, a lock screw engaged to a portion of the motor shaft for thereby closely contacting the ball nut to the inner end portion of the motor shaft, a groove formed in a rear portion of the motor shaft, and a stop ring inserted into the groove and supporting a rear portion of the lock screw, the improvement wherein:(a) the groove is circular with a tapered cross-section defined by an inner tapered surface; and (b) the stop ring is formed to be expandable in the outer radial direction, and is formed with an outer tapered surface opposite to the inner tapered surface of the groove for thereby being closely contacted with the groove based on a movement to the motor shaft direction along a central axis due to the expansion force of the stop ring.