This section examines the front wheel drive differential.
When a vehicle turns, the outer wheel travels a greater distance than the inner wheel, so it turns through more revolutions.
The differential allows the 2 drive shafts and the driving road wheels to rotate at different speeds when turning, while still applying an equal turning effort to both.
Differential gears are bevel gears, at right angles to each other inside a case, which is supported on bearings in the final drive housing.
The ring gear is bolted to the case, so when it rotates, so does the case, and the differential gears inside it.
The two smaller bevel gears, or pinions, are mounted on a driving pin which passes through the case.
Two side gears mesh with the pinions and are in recesses in the differential case. The drive shafts are splined to these side gears.
When the vehicle travels in a straight line, the ring gear rotates the case. The driving pin and pinion gears rotate end over end, turning the side gears with them, and the drive shafts.
There is no relative motion between the pinion gears and the side gears: each side gear turns at the same speed.
As soon as the vehicle turns from a straight ahead position, the inner wheel slows down and its side gear turns more slowly than the differential case.
The turning effort applied to the driving pin, forces the pinion gears to rotate slowly on the pin. They walk around the inner side gear while still being turned end over end.
This rotation of the pinion gears makes the outer side gear, and its road wheel, speed up by an equivalent amount. The outer side gear then turns faster than the case.
This provides an equal turning effort to each drive shaft while allowing for their speed difference.
Source: CDX Global
