Figure 21-10. Simple Dry Plate Clutch.
causes the Inner section to move out, and the movement
forward, holding all the disks together firmly. This causes
of the outer rim forces the pressure plate against the
the clutch spider to revolve and turn the clutch shaft to
clutch disk, thus engaging the clutch.
which it Is keyed. In multiple-disk clutches, the facings
usually are attached to the driving disks. This reduces
d. Multlple-Dlsk Clutch. Typical multiple-disk clutches
the weight of the driven disks and, consequently, their
tendency to continue spinning after the clutch is released.
are shown In figures 21-11 and 21-12. Disks ranging In
Because of the considerable number of disks Involved,
numbers from 2 to 10 (and often as many as 11 driving
the pressure plate has to move farther to separate the
and 10 driven disks for heavy vehicles) are used. The
disks completely than It does In clutches having fewer
driving disks have lugs similar to gear teeth around their
driving and driven members. There Is, therefore, less
outside edges. These mesh with Internal splines In the
mechanical advantage on the clutch pedal and a greater
clutch case, which Is bolted to and rotates with the
foot pressure Is required to depress it.
flywheel. The driven disks are carried on parallel pins,
which are solidly set In the clutch spider. This
e. In a wet-type clutch, the disks and the entire internal
construction permits movement of all the disks and the
assembly run In an oil bath. The operation of this type of
pressure plate in order to provide clearance between
clutch Is similar to that of the dry type, except that the
them. When the clutch is engaged, the spring moves the
friction surfaces are