differential gear

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differential gear

the epicyclic gear mounted in the driving axle of a road vehicle that permits one driving wheel to rotate faster than the other, as when cornering
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Differential Gear


a device that produces a resultant motion as the sum or difference of the component motions. In a differential gear with, one degree of freedom, the component motions are connected kinematically and are produced by a single drive; the resultant is produced as the difference of these motions. Differential gears with one degree of freedom are used for producing small, precise movements or great forces (for example, in instruments and metal-cutting lathes).

In differential gears with two or more degrees of freedom, the component motions are independent and each is performed by its own component element. There are a number of different types of such differential gears, but the most widely used is the differential gear with bevel gears (usually called simply a differential), which is used in motor vehicles and other transportation machines and in mechanical drives.

The relation between the effective velocities of the component elements of the differential gear is expressed by the formula ω1 + ω2 = 2ω or n1 + n2- 2nr, where ω1, ω2, and ωr and n1, n2nr are, respectively, the rates of angular motion and the frequencies of rotation of the central wheels and the carrier. In a speed regulator of the closed type, the differential gear permits broadening of the control range and makes possible reverse rotation of the driveshaft. In metal-cutting lathes the differential gear is used for simplifying tooling and reducing the number of change gears required. Differential gears are used in computers to perform the mathematical operation of parameter addition.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

differential gear

[‚dif·ə′ren·chəl ′gir]
(control systems)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Today special attention is paid to the method of controlling speed changes using single-stage and multistage differential gears with a closed hydraulic system [1-16].
It is a technology leader in its field with 85% market share of precision forged differential gears in India, 25% in the European market and 12% share of all vehicles globally.
In the Toyota Group's current driveline operations, Toyota, JTEKT, and Yutaka Seimitsu share responsibilities for development and production of each driveline component, with Toyota and Yutaka Seimitsu responsible for differential gears and JTEKT responsible for torque control devices (electronically controlled 4WD couplings).
As a result of an accident on a two-seat four-wheeled bicycle on a journey from Coventry to Birmingham with his son, William Starley invented differential gears. Many of us still ride bicycles.
The automaker is recalling the vehicles because defects in the vehicles' pinion gears could damage differential gears.
Driving a part-time 4WD system on dry pavement can break the front axles, shear the differential gears and even break apart the differential case.
Those heavy, obscene bouquets, held together by tightened lock washers, studs, and monstrous split pins, squabbling in stillness and transfixed in loving embraces, have a clear and definite origin in differential gears, with their winding mathematical mazes of pinions, axles, and swage blocks.
Lose enough oil and the differential gears can lock up.

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