| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a ball screw device that can suppress the deterioration of torque transmission efficiency, and to provide an electric power steering apparatus. <P>SOLUTION: A backflow passage L2 is formed by installing a circulation member 15 to a ball screw nut 13. Furthermore, when assuming a maximum internal contact ball C which internally contacts with the inside of the backflow passage L2 at an arbitrary position of the backflow passage, the backflow passage L2 is formed so that the diameter of the internal contact ball C becomes larger than the outside diameter of a ball 12 in an entire region of the backflow passage L2. Then, the backflow passage is formed so that the diameter of an internal contact ball C1 in a scoop-up region T1 including each tongue 24 in the backflow passage L2 becomes smaller than the diameter of an internal contact ball C2 in an adjacent region T2. <P>COPYRIGHT: (C)2012,JPO&INPIT |
