| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electric power steering system capable of reducing manufacturing man-hours and facilitating assembly. <P>SOLUTION: The electric power steering system includes a cylindrical motor shaft 21 into which a rack shaft 11 of a vehicle is inserted and which rotates based on driving of a motor, and a ball screw nut 40 connected to the cylindrical motor shaft 21 through an engagement section 43. By transmitting a driving force of the motor to the rack shaft 11 through the cylindrical motor shaft 21 and the ball screw nut 40, assist power that assists the operation of a steering system of the vehicle is applied to the rack shaft 11. Thus, a stepped portion 45 is formed on an outer-peripheral surface of the ball screw nut 40. An end 3d of a third housing 3c is disposed opposingly to a ball bearing 51 so that such a distance that the ball screw nut 40 can relatively move in a direction indicated by an arrow a2 to the cylindrical motor shaft 21 is regulated by "C+D". In addition, a length S of the engagement section 43 of the ball screw nut 40 is set to be longer than the "C+D". <P>COPYRIGHT: (C)2013,JPO&INPIT |
