Page 100 - Mechanical Engineer's Data Handbook

APPLIED MECHANICS 89

2.8.6 Cone clutch

By angling the contacting surfaces, the torque capacity
is increased; for example, for an angle of 9.6" the
capacity is increased by a factor of 6.
O=cone angle (to the shaft axis, from 8' upwards).

The theory is the same as for the disk clutch but with an
effective coefficient of friction

2.8.5 Disk clutch

The simplest type of clutch is the single-plate clutch in
which an annular plate with a surface of friction
material is forced against a metal disk by means of a
spring, or springs, or by other means. There are two
theories which give slightly different values of torque
capacity.

Uniform-wear theory 2.8.7 Multi-plate disk clutch

Let: A number of double-sided friction plates may be
F = spring force mounted on splines on one element, and correspond-
r, =outer radius of friction material ing steel contacting plates on splines on the other
ri =inner radius of friction material element. The assembly is compressed by a spring or
springs to give a torque capacity proportional to the
Maximum torque capacity T= Fp- (ro + Ti) number of pairs of contacting surfaces.
2
F Torque capacity T= n x torque for one plate
Maximum pressure pm =
2nri(ro-vi) where: n=number of pairs of surfaces (6 in the
example shown in the figure).

U7u
Detail of iiction plate
and pressure plate

Uniform-pressure theory
2.8.8 Centrifugal clutch

Internally expanding friction shoes are held in contact,
by the force due to rotation against the force of a light
spring. The torque capacity increases as the speed
increases.