| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor-driven power steering device as an improvement of a conventional arrangement in which a biasing member to bias a worm shaft toward a worm wheel is installed in the radial arrangement of the worm shaft as a mechanism to adjust backlash, involving the problem as enlarged dimensions. SOLUTION: In a bearing holding hole 41 formed in a lower housing 7, a second rolling bearing 14 supporting rotatably a first steering shaft 2 continued to a steering wheel 1 is held in such a way as capable of biasing in the direction going apart from the worm shaft 11. The inner ring 17 of the second rolling bearing 14 is tightly fitted on the first steering shaft 2. A moisture absorbing member 43 is interposed between a semi-circumference of the hole 41 on the worm shaft 11 side and the outer ring 16 of the second rolling bearing 14. The moisture absorbing member 43 is made of a synthetic resin having approximately an equal expansion amount by moisture absorption to a synthetic resin member 12b of the worn wheel 12, and biases the first steering shaft 2 through the second rolling bearing 14. |
