Differential is the main component of the power train. It is bolted on the rear axle and connects the propeller shaft to the rear wheels. While a vehicle taking a turn, its outer wheel run faster than the inner wheel. If we connects the propeller shaft by rear axle without using of differential gear, than the torque transmitted both the rear wheels is equal in any condition. So the both rear wheels will run at same speed while taking a turn which occur a problem in driving a vehicle. To eliminate this problem a device is used which is known as differential.
Differential is the mechanism of gears by means of which outer wheel runs faster than the inner wheel while taking a turn or moving over upheaval road. Differential is a part of the driving axle housing assembly, which includes the differential, rear axles, wheels and bearings. The differential consists of a system of gear arranged in such a way that connects the propeller shaft with the rear axle and transmit the different torque to rear wheels if necessary.
Construction of differential gear:
Differential is an arrangement of gears which work together and allow the vehicle to take a turn smoothly. In the differential bevel pinion gear is fixed to the propeller shaft which rotates the crown wheel. The crown wheel has another unit called the differential unit. It consists of two bevel gears (sun gear) and two bevel gears (planet gear). The bevel gears are in contact with the half shaft of the rear axle. When the crown wheel is rotating it rotates the differential unit. The bevel (sun) gears of the differential rotate the two shafts.
Working of differential gear:
When the car is on a straight road, the ring gear, differential case, differential pinion gears, and two differential side gears all turn as a unit. The two differential pinion gears do not rotate on the pinion shaft. This is because they exert equal force on the two differential side gears. As a result the side gears turn at the same speed as the ring gear, which causes both drive wheels to turn at the same speed also. However, when the car begins to round a curve, the differential pinion gears rotate on the pinion shaft. This permits the outer wheel to turn faster than the inner wheel.