Differential of an automobile

When the vehicle negotiates a curve, the path traveled by the inner wheel is shorter as compared to outer wheel. If we rigidly fixed the wheels to one axle and both (outer and inner) wheels move with the same speed then the inner wheel will skid which causes wear of the tire. It also affects the control of the vehicle. In front axles, the wheel can rotate independent of each other but in power wheels like the rear wheels, it is not possible so a special arrangement is made which is known as differential. The power from the propeller shaft passes to rear wheels through differential.

Working of differential: The main components of the differential mechanism are as follows.
1. Crown wheel
2. Cage
3. Sun gears
4. Planet pinions
The power from the propeller shaft bevel pinion goes to the crown wheel. Along with the crown, rotates the assembly of four bevel pinions (planet pinions and sun gears). Two bevel gears are carried on individual half axles which are connected to the rear wheels. When stationary, if one wheel is made to rotate in anticlockwise direction then the other wheel through the bevel gear assembly rotates in the clockwise direction.
If on a straight road the both the wheels are rotating at N rpm, and now if negotiating a curved path, if the inner wheel rotates at N-a rpm the outer wheel will rotate at N+a rpm.
When the vehicle negotiates a curve, the path traveled by the inner wheel is shorter as compared to outer wheel. If we rigidly fixed the wheels to one axle and both (outer and inner) wheels move with the same speed then the inner wheel will skid which causes wear of the tire. It also affects the control of the vehicle. In front axles, the wheel can rotate independent of each other but in power wheels like the rear wheels, it is not possible so a special arrangement is made which is known as differential. The power from the propeller shaft passes to rear wheels through differential.

Working of differential: The main components of the differential mechanism are as follows.
1. Crown wheel
2. Cage
3. Sun gears
4. Planet pinions
The power from the propeller shaft bevel pinion goes to the crown wheel. Along with the crown, rotates the assembly of four bevel pinions (planet pinions and sun gears). Two bevel gears are carried on individual half axles which are connected to the rear wheels. When stationary, if one wheel is made to rotate in anticlockwise direction then the other wheel through the bevel gear assembly rotates in the clockwise direction.
If on a straight road the both the wheels are rotating at N rpm, and now if negotiating a curved path, if the inner wheel rotates at N-a rpm the outer wheel will rotate at N+a rpm.