| 摘要 |
PROBLEM TO BE SOLVED: To prevent leakage of lubrication oil from a gear box without incurrling enlargement of a necessary electric motor.SOLUTION: A power transmission mechanism includes: an output shaft 420 which is rotatably arranged in an output through-hole 432 disposed in a gear box 430 and has an output end part exposed to an external part of the gear box 430; and a plurality of gears housed in an inside of the gear box 430, and is configured in such a way that the output shaft 420 is rotated via a plurality of gears when the power is input, wherein a circumferential wall part 433 having a cylindrical inner circumferential surface 433a on a portion opposite to an outer circumferential surface of the output shaft 420 is provided in the gear box 430, and on the outer circumferential surface of the output shaft 420, a helical protrusion part 423 is formed so as to proceed to an inside of the gear box 430 with respect to the circumferential part 433 when the output shaft 420 is forwardly rotated. |
