| 摘要 |
PURPOSE:To protect a gear from load change by providing a switch mechanism for selectively switching one of plural gears to transmit power of the gear to an output shaft on take-out side for load, and interposing a friction power transmission mechanism between an input gear and a gear on engine side. CONSTITUTION:In a speed change mechanism of a travelling mechanism 4, the second shaft 8 is rotatably supported by the first shaft 7, and an input gear (driven gear) for receiving engine output by gears 801, 802 is formed on a transmission case 6. A friction power transmission mechanism 9 is disposed between the large-diameter first input gear 801 and the small-diameter second input gear 802 on the shaft 8. This arrangement can effectively absorb load change in case of travelling with large load change. |
