The driven centre-plate is also called a clutch disc or friction disc.
The driven plate has a pair of friction facings, usually of wire-reinforced asbestos composition, carried on waved spring steel segments, which are riveted to a steel disc.
The central alloy-steel splined hub is separate. Drive is transmitted from the disc to the hub through heavy torsional coil springs or rubber blocks.
This spring hub arrangement dampens torsional vibrations from the engine. It also absorbs shock loads imposed on the drive line by sudden or violent clutch engagement.
Stops limit the radial movement of the hub against the spring force. A molded friction washer between the hub and spring retaining plate also acts as a dampener.
The waved spring steel segments cause the facings to spread slightly when the clutch is disengaged - then compress as it is engaged. This has a cushioning effect and provides smooth engagement.
Source: CDX Global
