machine and machine elements systems 7.ppt

Machine elements

1. clutch is a device used in transmission
system of a vehicle to transmit rotary
motion of one shaft when desired to
second shaft of which are coincident with
that of first.
Clutch is located in between engine and
the transmission system.
When the clutch is engaged , power
transmit from the engine to the driving
wheels through transmision system the
vehicle moves.
Friction Clutches
Visit for more Learning Resources

2. Types of Friction Clutches
1.Single plate clutches
2.Multiplate clutch
3.Centrifugal clutches

3. T
T
W (axial thrust)
W
Friction
plate
Friction
lining Pressure
plates
springs
Single-plate Friction Clutch (Disengaged position)
Driving
shaft
Driven
shaft
Flat-plate friction clutches

4. Single-plate Friction Clutch (Engaged position)
T
T
W (axial
thrust)
W
Friction plate
Friction
lining
Pressure
plates
springs
Driving
shaft
Driven
shaft
Flat-plate friction clutches

5. An example is the clutch found in most
automobiles.
Flat-plate friction clutches

8. Torsional
springs
Splined boss
(hub)
Friction
lining
Clutch plate or friction plate

9. Pressure
plate
Diaphragm
spring
Clutch
housing
Pressure plate and housing

11. In a multi plate clutch, the torque is
transmitted by friction between several pairs
of co-axial annular driving faces maintained
in contact by an axial thrust.
Both sides of each plate are lined with friction
material, so that a single-plate clutch has two
pairs of driving faces in contact.
Multi plate clutches

12. n = no. of pairs of driving faces.
Then, for a plate clutch, the maximum
torque transmitted is
m
WrnT
Multi plate clutches

13. No. of driving
pairs n = 6
driver driven
Pressure plates
Friction plates
21
43 65
Multi plate clutch

14. Exercise Problems

15. Problem 15
A car engine has its rated output of 12 kW. The
maximum torque developed is 100 N-m. The clutch
used is of single plate type having two active surfaces.
The axial pressure is not to exceed 85 kN/m
2
. The
external diameter of the friction plate is 1.25 times
the internal diameter. Determine the dimensions
of the friction plate and the axial force exerted by the
springs. Coefficient of friction = 0.3
[Ans. 129.5 mm ; 103.6 mm ; 1433 N]

16. Problem 16
A single plate clutch (both sides effective) is
required to transmit 26.5 kW at 1600 r.p.m.
The outer diameter of the plate is limited to
300 mm and intensity of pressure between
the plates is not to exceed 68.5 kN/m
2
.
Assuming uniform wear and a coefficient of
friction 0.3, show that the inner diameter of
the plates is approximately 90 mm.

17. Problem 17
A multi plate clutch has three pairs of contact
surfaces. The outer and inner radii of the
contact surfaces are 100 mm and 50 mm
respectively. The maximum axial spring force
is limited to 1 kN. If the coefficient of friction is
0.35 and assuming uniform wear, find the
power transmitted by the clutch at1500 r.p.m.
[Ans. 12.37 kW]

18. Problems
A multi-plate clutch is to transmit 12kW at
1500rev/min. The inner and outer radii for the plates
are to be 50mm and 100mm respectively. The
maximum axial spring force is restricted to 1kN.
Calculate the necessary number of pairs of surfaces if
=0.35 assuming constant wear. What will be the
necessary axial force?
(Answer, 3; 970N)

19. Driving
shaft
Driven
shaft
Friction
lining
α
The maximum torque transmitted =
α = semi-apex angle of
the cone
Only one pair of driving
surfaces is possible, n =1
Cone clutch
T = μWr
m
cosecα
w

23. Centrifugal clutch
Driving
shaft
Driven
shaft
Friction lining
Total friction torque , T = nµR(F-P)
F=mrω
2
ω
ω
P
R
For more detail contact us