Differential gear, in auto mechanics, gear arrangement that permits power from the engine to be transmitted to a couple of driving wheels, dividing the force equally between them but permitting them to follow paths of different lengths, as when turning a corner or traversing an uneven street. On a straight street the tires rotate at the same speed; when turning a corner the outside wheel offers farther to go and will turn faster compared to the inner steering wheel if unrestrained.
The elements of the Ever-Power differential are demonstrated in the Figure. The energy from the transmitting is sent to the bevel band gear by the drive-shaft Differential Gear pinion, both of which are held in bearings in the rear-axle housing. The case can be an open boxlike framework that is bolted to the band gear possesses bearings to support one or two pairs of diametrically opposite differential bevel pinions. Each steering wheel axle is mounted on a differential side equipment, which meshes with the differential pinions. On a straight road the tires and the side gears rotate at the same velocity, there is absolutely no relative motion between the differential aspect gears and pinions, plus they all rotate as a device with the case and ring gear. If the automobile turns left, the right-hand steering wheel will be forced to rotate faster than the left-hand wheel, and the medial side gears and the pinions will rotate relative to one another. The ring gear rotates at a rate that is add up to the mean quickness of the remaining and right wheels. If the wheels are jacked up with the transmitting in neutral and among the wheels is turned, the opposite wheel will submit the opposite direction at the same rate.
The torque (turning moment) transmitted to the two wheels with the Ever-Power differential is the same. Consequently, if one wheel slips, as in ice or mud, the torque to the other wheel is decreased. This disadvantage can be overcome relatively by the use of a limited-slide differential. In one version a clutch connects one of the axles and the ring gear. When one wheel encounters low traction, its inclination to spin is certainly resisted by the clutch, hence providing higher torque for the other wheel.
A differential in its most basic form comprises two halves of an axle with a equipment on each end, connected with each other by a third equipment creating three sides of a square. This is generally supplemented by a fourth gear for added power, completing the square.