1. Clutch
•Transmit rotary motion of one shaft to another when desired
•Couple the engine from transmission while
1)shifting gears
2)starting vehicle from rest
2. Types Of Clutch
Types of
Clutches
Positive
Clutch
Friction
Clutch
Plate Or
Disc Clutch
Single plate
clutch
Multiplate
Clutch
Cone Clutch
Centrifugal
Clutch
4. Uniform Pressure
Theory
Uniform Wear
Theory
)
(
F
P 2
2
i
o R
R
)
R
-
r(R
2
F
P
i
o
)
R
(R
)
R
(R
3
2
F
T 2
i
2
o
3
i
3
o
)
R
R
(
2
1
F
T i
o
Where,
P=normal pressure
F=axial force
=coefficient of friction
between the surfaces
T=friction torque
radius
inner
R
radius
outer
R
i
o
Where
Pr=constant
7. Uniform pressure theory Uniform Wear theory
2
i
2
o
3
i
3
o
R
R
R
R
3
2
F
μ
n
Τ
i
o R
R
2
1
μF
n
Τ
1
-
n
n
n 2
1
n1=number of plates on driving shaft
n2=number of plates on driven shaft
n =number of pair of active surfaces
8. Cone Clutch
• Contact surfaces are in form of cones
• Normal force on contact surface is increased
• More torque is transmitted
=semi-cone angle, w=width of cone
)
R
R
(
)
R
(R
3
2
F
sin
1
T 2
i
2
o
3
i
3
0
)
R
R
(
2
1
F
sin
1
T i
0
Uniform pressure
theory
Uniform
wear theory
i
R
o
R
w
R
-
R
sin
i
o
9. Centrifugal clutch
•Clutch is engaged only after a particular speed of motor
m=mass of each shoe R=inner radius of pulley rim
r=distance of centre of mass of p=max pressure intensity
each shoe from shaft axis n=number of shoes
=normal shaft speed ’=speed at which shoe
=angle shoe subtends at centre moves forward
=coefficient of friction between shoe and rim
l=contact length=.R , b=contact width
Total frictional torque=
Also,
R.n
).
'
mr( 2
2
p.l.b
)
'
mr( 2
2
10. Note:
1) New clutch - Uniform Pressure theory
2) Old clutch - Uniform Wear theory(used more often)
3) Single plate clutch - normally both sides of the plate are
effective - two pairs of contacting surface :- n=2.
Diagram
Centifugal clutch
