The principle of operation of the differential (Discovery 3)

Front and rear differentials have the same principle of operation. The rotary motion of the drive shaft is transmitted through the primary flange to the pinion shaft and pinion gear. The angular location of the drive gear in relation to the driven gear ensures the transmission of rotational motion at an angle of 90°.

Further, the rotational movement is transmitted to the driven gear, which, in turn, drives the differential housing. The shaft attached to the crankcase rotates at the same speed as the crankcase. The shaft-mounted planetary gears also rotate with the crankcase. The planetary gears, in turn, transmit rotational motion to the right and left sun gears, which rotate the axle shafts.

When the vehicle is moving in a straight line, the torques transmitted by the differential to each sun gear are the same. In this state, both axle shafts rotate at the same speed. The planetary gears do not rotate and securely fix the sun gears to the differential case.

When the car turns, the outer wheel rotates at a higher speed and travels longer than the inner wheel. The differential determines the difference in torque between the sun gears. The planetary gears begin to rotate on their axles, allowing the outer wheel to turn faster than the inner one.