ELECTRIC POWER STEERING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide an electric power steering apparatus which can efficiently convert the rotary motion of a motor shaft into the axial linear motion of a rack bar without loosening a lock nut and causing detrimental deformation of the motor shaft. SOLUTION: The electric power steering apparatus comprises the motor shaft 1, the rack bar 2, and a ball screw mechanism 3. The ball screw mechanism 3 has a ball nut 4 which integrally rotates together with the motor shaft 1, and a lock nut 5 which is screwed onto the motor shaft 1 from its one end 1a and fixes the ball nut 4 in the motor shaft 1. A cut-out portion 1b is formed on one end 1a of the motor shaft 1. The lock nut 5 is engaged with the motor shaft 1 by bending the thin wall portion 5b of the lock nut 5 toward the cut-out portion 1b. COPYRIGHT: (C)2005,JPO&NCIPI