| 摘要 |
PURPOSE:To reduce the noise of gears, by providing the first crankshaft with an auxiliary gear, and energizing the auxiliary gear by means of a spring in the turning direction of the first crankshaft. CONSTITUTION:On the first crankshaft 15, an auxiliary gear 25 which is engaged with the main gear 27 fitted on the second crankshaft 17 is fitted, and the auxiliary gear 25 is energized by a coil spring 41 in the direction in which the tooth surface 23A facing to the turning direction A of the main gear 23 of the first crankshaft 15 and the tooth surface 27A of the main gear 27 of the second crankshaft 17 opposing to the tooth surface 23A are becoming disengaged. Thus, when the crankshaft 15 becomes the driving side, the auxiliary gear 25 functions as a damper, therefore the noise of gears can be reduced. When the crankshaft 17 becomes the driving side, since the backlash between tooth surfaces 27B, 23B (both are not shown) being impacted by the auxiliary gear 25 has been reduced, the noise of gears reduces. |
