In passenger cars, the final drive usually consists merely of a hypoid bevel-gear drive. The geometry of the bevel-drive pinion and of the crown wheel determines the final-drive ratio (i0=2.24~4.93 for standard-production vehicles) (Fig. 3-18). The hypoid gear is in common use today due mainly to the fact that the offset pinion allows the propeller shaft to be set below (for cars), or above (for commercial vehicles) the crown wheel center. This gives either a reduction in the propeller shaft tunnel, which causes a bump in the vehicle floor, or in the case of a commercial vehicle a reduction in the angle though which the universal joint has to operate.
In commercial vehicles, the necessary final-drive ratio can only rarely be accommodated in one stage (bevel-gear drive). For this reason, use is usually made of more elaborate final-drive systems:
1) single-reduction axle (up to i0=7) ,
2) transmission-type axle with front-or top-mounted bevel-gear drive,
3) double-reduction axle (total transmission ratio up to i0=9),
4) pinion axle (spur-gear drives in the wheel hubs),
5) planetary-hub reduction axle (also shiftable in special cases).
Large crown wheels reduce the ground clearance under the differential. In the case of pinion axles and planetary-hub reduction axles, the differential and the half-shafts can be made smaller by splitting the reduction. This makes it possible, even in the case of high power outputs, to achieve sufficient ground clearance of the vehicle.
在商业车辆,必要的最终传动比只能很少能容纳一个阶段(伞齿轮驱动器)。出于这个原因,通常由使用更精细的最终驱动系统:
1)单减桥(最高至I0 = 7),
2)传输型轴与前端或顶部安装的伞齿轮传动,
3)双减桥(总传动比达至I0 = 9),
4)小齿轮轴(轮毂中直齿轮传动),
5)行星减速桥枢纽(在特殊情况下也可移位)。
大冠车轮下的差别减少离地间隙。在小齿轮轴与行星集线器减少车桥,差速器和半轴较小的情况下,可通过把减少。这使得即使在高功率输出的情况下,实现对车辆有足够的离地间隙。
在商业车辆,必要的最终传动比只能很少能容纳一个阶段(伞齿轮驱动器)。出于这个原因,通常由使用更精细的最终驱动系统:
1)单减桥(最高至I0 = 7),
2)传输型轴与前端或顶部安装的伞齿轮传动,
3)双减桥(总传动比达至I0 = 9),
4)小齿轮轴(轮毂中直齿轮传动),
5)行星减速桥枢纽(在特殊情况下也可移位)。
大冠车轮下的差别减少离地间隙。在小齿轮轴与行星集线器减少车桥,差速器和半轴较小的情况下,可通过把减少。这使得即使在高功率输出的情况下,实现对车辆有足够的离地间.
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