| 摘要 |
PURPOSE:To make a reduction gear ratio for ahead two speed gears alterable at will regardless of that of an ahead one-speed gear, by meshing ahead one- speed input gears and ahead two-speed input gears with different input gears respectively. CONSTITUTION:Ahead one-speed input gears 7 and 7 and ahead two-speed input gears 11 and 11 are so constituted each that the former's driving force is transmitted by an astern input gear 1 while the latter's is transmitted by an ahead two-speed driving input gear 16 respectively. With this, the reduction gear ratio of the ahead two-speed gear becomes determined by a gear ratio with the ahead two-speed driving input gear 16 being independent of the ahead one-speed gear, so that both reduction ratios for the ahead one-speed gear and the ahead two- speed gear are not bound to each other, freely selectable and, what is more, an optional reduction gear ratio can be secured in accordance with the demand, in case of a speed reduction reversing gear using the same case. |
