# Differential Gear of an automobile

Differential gear used in the rear drive of an automobile is shown in Fig.1 function is
(a) to transmit motion from the engine shaft to the rear driving wheels.

(b) To rotate the rear wheels at different speeds while the automobile 15 taking a turn.

As long as the automobile 18 running on a straight path, the rear wheels are driven directly by the engine and speed of each the wheels is same. But when the automobile 18 taking a turn, the outer wheel will run faster than the inner wheel because at that time the outer rear wheel has to cover more distance than the inner rear wheel.
This is achieved by planet wheel train With bevel gears as shown in Fig. the bevel gear A (known as opinion) is keyed to the propeller shaft is driven from the engine shaft through ‘ universal coupling. This gear A drives the gear B (known as crown gear) that rotates freely on the shaft P. Two equal gears C and D are mounted on 2 separate parts P and alphabetic character of the rear axles severally. These gears, in turn, mesh with equal pinions E and F which might rotate freely on the spindle provided on the arm connected to gear B.When the autoruns on a straight path, the gears C and D should rotate along. These gears are rotated through the spindle on the gear B. The gears E and F don’t rotate on the spindle. But when the automobile 18 taking a turn, the inner rear wheel should have lesser speed than the outer rear wheel and due to the relative speed of the inner and outer gears D and C, the gears E and F begin rotating regarding the spindle axis and at an equivalent time touch the axle axis.