The multiple-disc clutch connects two shafts (drive-coupling) with each other, or as a rib brake, a shaft with the casing (brake clutch). If the working pressure of the clutch is electrically controlled (figure 1), this pushes relatively steadily against a diaphragm spring onto all the axially movable ribs (friction washers). Because, e.g., first, third, fifth etc. are solidly connected inside with the shaft, and second, fourth, sixth etc. outside with a bell-shaped casing, a force-locked connection is produced between the shaft and the casing.
There are also multiple-disc clutches which are operated directly, e.g., as an oil-bath clutch in mopeds or as a dry clutch in motorcycles (figure 7). Whereby, the dry clutch has the fundamental advantage of developing higher friction. Apart from this, any oil remaining in the clutch causes less drag momentum. The oil-bath clutches are rather less problematic in normal use.
As can be seen in the above figures, the operational areas of multiple-disc clutches in the drive-system are varied. They are found in clutches, automatic-, transfer gearboxes and final drives, mostly as a drive-, seldom as a brake clutch. With the automation of the clutch they have increased somewhat because they react, particularly as an oil-bath clutch, more gently than e.g., a single-disc dry clutch. The better the automatic control, and the larger the diameter, the more likely that its proliferation will also decrease again. 09/08