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Analysis of Open and Torsen Differential. Group Members: Scott Anderson Michael Bullard Jason Yount. When turning, the inner and outer wheels have arcs of different turning radii Consequently, the inner wheels travel less distance than the outer wheels. Differential Overview.
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Analysis of Open and Torsen Differential Group Members: Scott Anderson Michael Bullard Jason Yount
When turning, the inner and outer wheels have arcs of different turning radii Consequently, the inner wheels travel less distance than the outer wheels Differential Overview
Because the turning paths of the inner and outer wheels are different, the wheels on both axles need to be able to spin independently of each other A differential is used to allow the wheels to spin at different speeds Differential Overview
Open Differential Limited Slip Differential (LSD) Clutch LSD Viscous Coupling LSD Locking LSD Torsen LSD Different Types of Differentials
Schematic of an Open Differential • The “Sun” gear and “Ring” gear are identical and supply power to the drive axles. • The planetary gears, or spider gears allow the axles to rotate at different speeds.
The open Differential is a planetary gear set. Therefore the following equation applies Open Differential
Open Differential • The number of teeth on the ring gear and sun gear are equal and the planetary gear formula is simplified • The angular velocity of the differential is equal to the average angular velocity of the axles
Open Differential Problems • As a result, if one wheel has little friction there is no resistance to its rotation and slipping occurs • The slipping wheel will spin twice as fast as the differential Left rear tire slipping on sandy surface
The Torsen Differential is capable of perfect differentiation The Torsen Differential transfers power to the wheels with traction The Torsen Differential Torque transferred to wheel with traction
Power is transferred from the engine to the differential housing causing the housing to turn Power flows from the housing to the worm wheels attached to the housing The worm wheels are meshed with the worm gears attached to the axles which turns the axle with the differential housing How the Torsen Differential Works
When turning, the outer wheel turns at a high RPM with respect to the differential housing Therefore, the outer wheel axle turns its worm gear and its mating worm wheel The mating worm wheels are meshed together by spur gears Perfect Differentiation: as one wheel increases speed the other wheel decreases speed proportionally Torque is maintained at both wheels while cornering Differential Function
Spinning wheel turns its worm gear which turns its mating worm wheel Mating worm wheel wants to turn opposite worm wheel Opposite worm wheel transfers power to opposite worm gear Traction Loss By One Wheel
Opposite worm gear is attached to the axle of the wheel with traction The slipping wheel does not spin Torque is transferred to the wheel with traction Traction Loss By One Wheel
The torque bias ratio determines the amount of torque transferred and is dependant on the gear design 5:1 ratio transfers 5 times the torque to the wheel with traction If one wheel loses all traction no torque is transferred to the wheel with traction Torque Transfer Torque transferred to wheel with traction
Torsen differentials are used in off-road and high performance all-wheel drive vehicles. Torsens can also be handy on icy or dirt roads Application of Torsen Differentials
AM General Audi BMW Ford GM More specific details at http://www.torsen.com/oem.htm Honda Lexus Land Rover Mazda Toyota Volkswagen Automobile Companies Using the Torsen Differential
Companies Using Torsen Differential • General Motors • Camaro SS 1998 • AM General • Hummer • Audi • A4 Quattro • BMW • Z3