coupling China differential gear, in auto mechanics, gear arrangement that permits power from the engine to be transmitted to a set of generating wheels, dividing the force equally between them but permitting them to check out paths of different lengths, as when turning a corner or traversing an uneven road. On a straight road the tires rotate at the same quickness; when turning a corner the outside wheel offers farther to proceed and can turn faster compared to the inner wheel if unrestrained.
The elements of the Ever-Power differential are demonstrated in the Figure. The power from the transmitting is delivered to the bevel band equipment by the drive-shaft pinion, both of which are held in bearings in the rear-axle housing. The case can be an open boxlike framework that’s bolted to the band gear possesses bearings to support one or two pairs of diametrically opposite differential bevel pinions. Each wheel axle is attached to a differential side equipment, which meshes with the differential pinions. On a straight road the tires and the medial side gears rotate at the same swiftness, there is absolutely no relative motion between the differential part gears and pinions, and they all rotate as a device with the case and band gear. If the automobile turns left, the right-hand steering wheel will be required to rotate faster compared to 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 swiftness that is equal to the mean rate of the still left and right wheels. If the tires are jacked up with the tranny in neutral and one of the tires is turned, the contrary wheel will submit the 
opposite path at the same quickness.
The torque (turning minute) 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 steering wheel is decreased. This disadvantage can be overcome somewhat by the use of a limited-slide differential. In one version a clutch connects among the axles and the ring gear. When one steering wheel encounters low traction, its inclination to spin is usually resisted by the clutch, therefore providing greater 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 jointly by a third equipment making up three sides of a sq .. This is usually supplemented by a 4th gear for added strength, completing the square.