Fig. 64.—“I. H. C.” Chain Drive, Showing the Differential
[Figure 64] shows one of the large bevel gears of a differential, with the three small gears, the other large bevel gear being removed. A differential in section is shown in [Figure 65].
A tractor with only one driving wheel has no differential. Such tractors usually have two wheels, but one of them runs loose on the axle, and serves only to support the tractor. The rear axle construction of a tractor with a 1-wheel drive is shown in [Figure 66], which should be compared with the 2-wheel rear construction shown in [Figure 65].
Fig. 65.—“Case” Rear Axle
There are a number of methods used for transmitting power to the driving wheels. In [Figure 64] a chain is used; there are tractors with but one chain, and others with a chain for each driving wheel.
Fig. 66.—“Oil-Pull” Rear Axle
The most usual method is by a master gear, or bull gear, which is a large and heavy gear attached to the driving wheel, as shown in [Figures 65] and [66]. In some tractors this gear is nearly the size of the wheel, and is fully exposed; in others it is smaller, and enclosed in an oil-tight housing.
