Differential gear, in auto mechanics, gear arrangement that permits power from the engine to be transmitted to a set 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 road. On a straight road the tires rotate at the same speed; when turning a part the outside wheel offers farther to go and will turn faster compared to the inner wheel if unrestrained.

The elements of the Ever-Power differential are proven in the Figure. The energy from the tranny is delivered to the bevel ring gear by the drive-shaft pinion, both of which are kept in bearings in the rear-axle housing. The case can be an open boxlike structure that’s bolted to the band gear possesses bearings to support a couple of pairs of diametrically reverse differential bevel pinions. Each steering wheel axle is mounted on a differential side gear, which meshes with the differential pinions. On a straight road the wheels and the side gears rotate at the same velocity, there is no relative motion between your differential aspect gears and pinions, and they all rotate as a unit with the case and ring gear. If the automobile turns left, the right-hand wheel will be forced to rotate faster than the left-hand wheel, and the medial side gears and the pinions will rotate in accordance with one another. The ring gear rotates at a quickness that is equal to the mean quickness of the left and correct wheels. If the tires are jacked up with the transmitting in neutral and one of the tires is turned, the contrary wheel will submit the Differential Gear opposite path at the same speed.

The torque (turning moment) transmitted to both wheels with the Ever-Power differential may be the same. Consequently, if one wheel slips, as in ice or mud, the torque to the other steering wheel is reduced. This disadvantage can be overcome somewhat by the utilization of a limited-slip differential. In one version a clutch connects one of the axles and the ring gear. When one steering wheel encounters low traction, its inclination to spin is certainly resisted by the clutch, therefore providing better torque for the additional wheel.
A differential in its most elementary form comprises two halves of an axle with a gear on each end, linked with each other by a third gear making up three sides of a square. This is generally supplemented by a 4th gear for added power, completing the square.