Planetary gear transmission systems or components – Differential planetary gearing – Bevel gear differential
Reexamination Certificate
2000-01-07
2002-03-12
Marmor, Charles A. (Department: 3681)
Planetary gear transmission systems or components
Differential planetary gearing
Bevel gear differential
Reexamination Certificate
active
06354979
ABSTRACT:
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to vehicle drives, and particularly to differentials used in vehicles. More particularly, the present invention relates to limited-slip differentials for transferring drive power to the wheels in a vehicle.
Vehicles include laterally displaced drive wheels. During cornering, the outer drive wheel travels a greater distance than the inner drive wheel. Thus, the outer drive wheel must rotate faster than the inner drive wheel to cover the greater distance. Otherwise, one of the drive wheels will “skid” during cornering.
Differentials are provided on vehicles to permit the outer drive wheel to rotate faster than the inner drive wheel during cornering while both drive wheels continue to receive drive power from the engine. Thus, the outer drive wheel can travel a greater distance than the inner drive wheel while both drive wheels continue to drive the vehicle.
While differentials are useful in cornering, they can allow vehicles to lose traction, for example, in snow or mud or other slick medium. If either of the drive wheels loses traction, it will spin at a high rate of speed and the other wheel will not spin at all. Thus, one drive wheel spins at a high rate of speed without any traction to drive the vehicle; the other drive wheel does not spin; the vehicle receives no driving force from the drive wheels; and the vehicle is stuck.
To help eliminate this drawback of differentials, limited-slip differentials are provided to shift power from the drive wheel that has lost traction and is spinning in the snow or mud to the drive wheel that is not spinning. Thus, while one drive wheel spins in the snow or mud, power is shifted to the other drive wheel by the limited-slip differential to pull or push the vehicle out of the snow or mud.
Features of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the invention. The detailed description particularly refers to the accompanying figures in which:
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www, Auburngear.com, Limited-Slip Differentials, six pages, date unknown.
www.csn.ul.ie/~lavelles/difop.html, Materials on Differentials, seven pages, date unknown.
www.engineering.btr.com, BTR Engineering Australia, Transmission & Axle Division, four pages, date unknown.
Barnes & Thornburg
Hoffco/Comet Industries, Inc.
Marmor Charles A.
Parekh Ankur
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