Differential gear, in automotive mechanics, gear arrangement that permits power from the engine to be transmitted to a couple of generating wheels, dividing the force equally between them but permitting them to follow paths of different lengths, as when Differential Gear turning a corner or traversing an uneven road. On a straight road the tires rotate at the same rate; when turning a corner the outside wheel offers farther to move and will turn faster than the inner wheel if unrestrained.
The elements of the Ever-Power differential are demonstrated in the Figure. The power from the tranny is delivered to the bevel ring gear by the drive-shaft pinion, both which are held in bearings in the rear-axle housing. The case is an open boxlike structure that is bolted to the ring gear possesses bearings to support one or two pairs of diametrically opposing differential bevel pinions. Each steering wheel axle is mounted on a differential side gear, which meshes with the differential pinions. On a directly road the tires and the side gears rotate at the same acceleration, there is absolutely no relative motion between the differential part gears and pinions, and they all rotate as a device with the case and ring gear. If the automobile turns to the left, the right-hand wheel will be forced to rotate faster than the left-hand wheel, and the side gears and the pinions will rotate in accordance with one another. The ring gear rotates at a velocity that is add up to the mean acceleration of the left and right wheels. If the tires are jacked up with the transmission in neutral and among the wheels is turned, the opposite wheel will submit the opposite path at the same quickness.
The torque (turning instant) transmitted to the two wheels with the Ever-Power differential is the same. Therefore, if one wheel slips, as in ice or mud, the torque to the other wheel is decreased. This disadvantage can be overcome somewhat by the use of a limited-slide differential. In one edition a clutch connects among the axles and the band gear. When one steering wheel encounters low traction, its inclination to spin is usually resisted by the clutch, hence providing higher torque for the various other wheel.
OPEN DIFFERENTIAL:
A differential in its most elementary form comprises two halves of an axle with a equipment on each end, linked with each other by a third equipment making up three sides of a square. This is usually supplemented by a 4th gear for added strength, completing the square.