| 摘要 |
PROBLEM TO BE SOLVED: To suppress a decrease of lubricant encapsulated in a mechanism part including a screwing part of a feed screw mechanism, and supply the lubricant stably to the screwing part.SOLUTION: A steering mechanism comprises: a rod 16 which comprises a first bottomed hole 16d along a shaft center and a female screw 16a formed in the first bottomed hole 16d, and steers left and right wheels 10, 11; a shaft 17 which comprises a second bottomed hole 17f along the shaft center, a communication hole 17g penetrating from the inner diameter surface of the second bottomed hole 17f over the peripheral surface, and a male screw 17a formed on the peripheral surface, and is rotated in a radial direction by driving force of drive means. By screwing the male screw 17a of the shaft 17 into the female screw 16a of the rod 16, a first space 54 and a second space 55 which are communicated by the communication hole 17g are formed between the rod 16 and the shaft 17. When varying a screwing amount, the volumes of the first space 54 and the second space 55 are changed, and lubricant filled in the spaces goes back and forth inside the closed spaces while lubricating the screwing part. |
