10-11-2012, 05:52 PM
Automobile Differential and Transmission
Automobile Differential.ppt (Size: 1.29 MB / Downloads: 392)
What is a differential?
Differential is a device capable of transmitting torque and rotation through three shafts, almost always used in one of two ways. In one of these, it receives one input and provides two outputs; this is found in most automobiles. In an automobile and other wheeled vehicles, the differential allows each of the driving wheels to rotate at different speeds, while supplying equal torque to each of them.
Purpose of a differential
The differential is found on all modern cars and trucks, and also in many all-wheel-drive vehicles. These all-wheel-drive vehicles need a differential between each set of drive wheels, and they need one between the front and the back wheels as well, because the front wheels travel a different distance through a turn than the rear wheels.
Differential Gear Train on a Turning Car
The outer wheel traverses an arc with radius ro and the inner wheel traverses an arc with radius ri. As illustrated, the lengths of the arcs traversed are so, sn, and si. The outer arc so is obviously larger than the inner arc si for a given traversed angle theta. Some way of ensuring that the outer wheel is able to turn slightly faster than the inner wheel must be ensured in order to prevent binding and slippage of the tires on the road.
Automobile Differential in Unigraphics
Before we started our project, we researched the dimensions and overall shape of a differential system on internet and by visiting a car mechanic shop. After we acquired the necessary data, we started to construct our differential system by using Unigraphics. We reduced and normalized the dimensions that we collected for easier application to unigraphics.
Autmobile Transmission
Most modern gearboxes either reduce an unsuitable high speed and low torque of the prime mover output shaft to a more stable lower speed with higher torque, or do the opposite and provide a mechanical advantage (i.e increase in torque) to allow higher forces to be generated.