Browse Publications Technical Papers 2010-36-0455
2010-10-06

FPS - Friction Pad System 2010-36-0455

The synchronization system was created with the intention to make easy the gear engaging in automotive transmissions. The speed difference of the shafts is reduced during the gearshift operation by means of sliding friction of the synchronizer rings. The constant friction performance can be improved and the wear can be simultaneously reduced either by additives in the oil of the transmission or by careful selection of the friction material for the synchronizer rings.
Nowadays, brass or steel meet the requirement of both friction surface and resistance on the driving lugs. The friction coefficient of the surface can be increased by scatter sintered coatings, molybdenum or carbon linings that are joined to the carrier material using complex manufacturing processes.
A new concept transforms this continuous friction lining into many single friction elements that are guided by "pockets" in the synchronizer ring. These "friction lining pads" require less material than the conventional solution (steel and friction compound) which leads to a reduction in the overall weight, especially in cases where non-metallic friction material is used. This increases the efficiency by equal performance and reduced drag torque, and also reduces the losses in the gearbox which is a benefit for fuel-saving drive trains. In addition, the material of the carrier supports higher mechanical stresses, because steel is used instead of brass. Also materials characterized by excellent friction properties when used as friction linings can be chosen.
In theory almost every material can be used as friction pads, such as the already proven scatter sintered coatings or any combination of materials. Optimum friction elements for such systems include pads made with nonmetallic materials, as various resins containing friction modifiers or pads from known brass alloys.

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