Viscous coupling unit
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A viscous coupling is made up of alternating circular plates. The plates have tabs or perforations in them. The plates are mounted in a sealed drum, which are located very close to each other. The drum is filled with silicon. When the two sets are plates are rotating in unison, the silicon stays cool and remains in a liquid state. When the plates start rotating at two different speeds, the sheer effect of the tabs or perforations on the silicon will cause the silicon to heat up and solidify (Silicon when heated will turn into a near solid). The silicon in this state will essentially glue the plates together and transmit power to both sets of plates. The size of the tabs or perforations on the plates, along with the number of plates will determine when this mechanical transfer will happen. Viscous couplings can be found in the center differential of some AWD vehicles, and also in the differential of Limited slip rear axles (LSD).
[edit] External links
- http://auto.howstuffworks.com/differential9.htm - Contains an interactive animation.
- http://syncro.org/VCTest.html
^http://www.autozine.org/technical_school/traction/tech_traction_4wd_2.htm
