| 摘要 |
PROBLEM TO BE SOLVED: To provide a steering device decreasing size and weight, and having a feed screw mechanism saving a manufacturing cost. SOLUTION: A ratio of the width W2 of threads of feed nuts 55. 65 to the width W1 of threads of feed screw shafts 53, 63 is formed in proportion to material strength of the feed nuts 55, 56 and a reciprocal number of the feed screw shafts 53, 63. The feed nuts 55, 65 and the feed screw shafts 53, 63 have the same load resistance of the threads at a screw position, so that the axial length (an engaging length) LN of the feed nuts 55, 56 can be made to be short. The feed nuts are downsized, and the weight of the feed nut becomes light. Furthermore, the manufacturing cost can be reduced. Furthermore, the width W1 of the threads of the feed screw shafts 53, 63 becomes small, so that the weight of the feed screw shafts is decreased, and the manufacturing cost can be saved. COPYRIGHT: (C)2008,JPO&INPIT |
