| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power steering device capable of reducing noise generated by vibrations inputted to a rack shaft. SOLUTION: The electric power steering device 1 comprises a hollow cylinder motor shaft 5 rotationally driven by an electric motor, the rack shaft 6 coaxially inserted in the motor shaft 5, and a ball screw mechanism 12 converting rotational motion of the motor shaft 5 into motion in an axial direction of the rack shaft 6. The ball screw mechanism 12 has a spiral ball rolling groove 15 on an inner peripheral surface, and comprises a nut 13 integrally rotating coaxially with the motor shaft 5, a plurality of balls 16, ..., 16 rolling along the ball rolling groove 15, a male screw 14 combined with the nut 13 through the plurality of balls 16, ..., 16 and coaxially coupled to the rack shaft 6, a pair of bushes 22, 22 arranged at both ends of the male screw 14, and an O-ring 23 arranged on an inner peripheral surface of the male screw 14. COPYRIGHT: (C)2006,JPO&NCIPI |
