Wet Friction
Multi-plate “wet” clutches and brakes have been proven to be ideal torque transfer devices for high energy applications. The multi plate clutch comprises of alternate friction and steel plates which interact within an oil cooled tribological system to transmit the desired torque.
The friction plate consists of a steel core plate and an appropriate friction material. The Schaeffler Friction Products friction materials available are “paper”/organic friction, sintered metal, elastomeric as well as graphitic materials. The majority of applications however use "paper" friction material. Paper is perhaps an inexact description of the material; it refers to the manufacturing process and not to the product. The engineered fibre matrix is manufactured on a Fourdrinier wire paper-making machine; the aqueous slurry of fibres and fillers is deposited on a moving wire. After that, so-called wafers (rings of friction material) are punched out of the dried “paper”, impregnated with resin, dried and bonded with adhesive to the steel core plates.
Multi-plate “wet” clutches are used in a broad spectrum of applications such as:
- Clutches in double clutch transmissions
- Torque converter lock up clutches
- Clutches and brakes in automatic transmissions
- Wheel and axle brakes
- Differential locks
- All wheel drive transfer cases
- Power take offs
- Master clutches
Hot-Spots
Hot Spot Analysis
These are only a few examples of many complex applications.
Schaeffler Friction Products is the specialist in the area of the tribology and friction plate technology, committed to quality and innovation. Our own paper development and production facilities, and the latest testing equipment and production techniques enables us to develop new materials and optimise for individual customer applications. Innovative successes in friction technology are being achieved using the newest fibre and resin technologies available. The optimization of a material’s tribological and surface properties is conducted through our research and development team, consisting of international chemists and engineers.
In addition to developing new friction materials and processes, Schaeffler Friction Products also has an expertise in thermo mechanical FEA- and simulation methodology to assist in the design of customer-specific clutch applications for the entire world-wide market Whether for the optimization of frictional behaviour, shift quality, frictional NVH or, for example, the resolution of thermal elastic instability problems such as hot spots or clutch plate distortion - our simulation techniques, test benches and field tests allow a customer tailored design optimisation and verification program.
The combination of almost twenty base papers with a variety of resin types and processing techniques offers a wide variety of possible “paper” friction materials. Schaeffler Friction Products’ application and development engineers have extensive experience and are available to assist in the design of clutches and brakes. Through close contact with our customers, we develop specific solutions to fulfil the required design specification. Through the selection of the appropriate fibre matrix to the specification of the steel mating surface, Schaeffler Friction Products will specify the complete tribological system that provides the required frictional characteristics to meet our customer’s requirements.
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