| 摘要 |
<p>A pinion gear unit includes a rotation member which rotates according to the rotation of a output rotation shaft, a first pinion gear which is fit to the rotation member through a first serration unit, rotates with the rotation member according to the rotation of the output rotation shaft, and moves with the rotation member if the pinion gear unit moves towards an engagement location by a pushing mechanism, to be initially engaged with an engine starting gear, and a second pinion gear which is fit to the rotation member to be adjacent to the first pinion gear through a second serration unit, rotates with the rotation member according to the rotation of the output rotation shaft, and moves with the rotation member if the pinion gear unit further moves towards the engagement location, to be engaged with the engine starting gear later than the first pinion gear, in a state where the first pinion gear is engaged with the engine starting gear, and the fitting is performed by the first and second serration units so that phases of teeth of the first pinion gear and teeth of the second pinion gear in a circumferential direction correspond with each other.</p> |
