| 摘要 |
A constant mesh gearbox having a plurality of selectable speed ratios and comprising a casing 20 defining five parallel rotational axes 31 35, including input 31 and output 35 axes and three intermediate axes 32 34. Gear pairs are provided for driving between axes. Preferably the gearbox has six sequential speed ratios in a first rotatable direction of an output (69, Figure 5). Optionally a first 12 and second 13 layshafts which drive an output (69) via layshaft output gear wheels (66, Figure 4), (67, Figure 5). A third layshaft 14 may be provided on the third intermediate axis 34 and have a sleeve (74, Figure 5) where the sleeve (74 and first layshaft (12) are connected by a gear pair (75, 76, Figure 5). Optionally a higher speed ratio is in the range of 60 75% of its numerically adjacent lower speed neighbour. A reverse ratio to provide for a second rotatable direction of the output member (69) may be provided. There may be provided a shaft 14 on a first intermediate axis 34 having a sleeve (74) rotatable thereon, the sleeve (74) being connected by a gear pair (75, 76) to a another shaft 12 provided on a second intermediate axis 32. |
