it is Classification of clutches, torque transmission capacity, considerations for uniform wear and uniform pressure theory under theory of machine

1. THEORY OF MACHINE
Classification of clutches, torque
transmission capacity, considerations
for uniform wear and uniform
pressure theory

2. What is clutch
• The Clutch is a mechanical device used to connect or disconnect the driven
shaft from the driving shaft at the will of the operator while power is
transmitted from driving to drivenshaft.
• Clutch is mounted between driving and driven shaft and power is
transmitted from one shaft to the another shaft which is required to be
started and stoppedfrequently.

3. Location of clutch

4. Different clutch positions

5. Classification

6. Positive Clutch
• In this type of clutch, the engaging clutch surfaces interlock to
produce rigid joint they are suitable for situations requiring simple &
rapid disconnection, although they must be connected while shaft
are stationary & unloaded.
• The jaw may be square jaw type or spiral jaw type.
• They are designed empirically by considering compressive strength of
the material used.

7. Positive Clutch

8. Friction Clutch
• Friction Clutches work on the basis of the frictional forces developed
between the two or more surfaces in contact. Friction clutches are
usually over the jaw clutches due to their better performance. There
is a slip in friction clutch.
 The major types of friction clutches are
I. Single Plate Clutch
II. Multi Plate Clutch
III. Cone Clutch
IV. Centrifugal Clutch

9. Single Plate Friction Clutch
• A single plate friction clutch consisting of two flanges. One flange is
rigidly keyed in to the driving shaft, while the other if free to move
along the driven shaft due to spliced connection. The actuating force
is provided by a spring.

10. Multi Plate Friction Clutch

11. CONE CLUTCH
• Cone clutches are friction clutches. They are simple in
construction and are easy to disengage. However, the
driving and driven shafts must be perfectly coaxial for
efficient functioning of the clutch.
• This requirement is more critical for cone clutch
compared to single plate friction clutch. A cone clutch
consists of two working surfaces, viz., inner and outer
cones

12. Centrifugal Clutch
• The centrifugal clutch permits the drive motor to start, warm up and
accelerate to the operating speed without load. Then the clutch is
automatically engaged and the driven equipment is smoothly brought
up to the operating speed.

13. Torque transmitted by single plate clutch is
obtained as follows
• R1 = External radius of clutch plate R2 = Internal radius of clutch plate
r = Small elemental ring of radius

14. • Area of the ring on contacting surface is,
• Axial load on the ring is,
• Frictional resistance offered by ring is,
• Frictional torque acting on ring is,
 1...........2 2
rprrFT rr 
rrA  2
rrpW  2
rprWFr  2

15. Uniformpressuretheory
• Torque transmitted by single plate clutchis obtained by considering
following two assumptions:
• Uniform pressuretheory
• Uniform weartheory
• Assuming that the intensity of pressure over the entire
contacting surfaces area is constant, then,
• p = Constant
• Pressure is uniformly distributed over the contacting surfaces area,
 2
2
2
1areasurfaceContacting
Load
RR
W
p




16. • Total torque transmitted by single plate clutch can be obtained by
integrating the Equation (1) within limits R2 to R1
• Equation (2) gives the torque transmitted single plate clutch due to
friction considering uniform pressure theory.
 
1
2
2
0
2
R
R
T
r rprT 
   
    
 2....
p
2
2
2
2
2
1
3
2
3
1
3
2
2
2
2
1
3
2
3
12
2
2
1
3
2
3
2
3
13
2
3
2
0
1
2
3
1
2




















 
RR
RR
WT
RR
W
RR
RR
W
T
RRppT
rrpT
R
R
r
R
R
T
r







17. Uniform wear theory
• In this theory, we are considering that wear which take place is
uniform over the entire contacting surface i.e.
• p.r = Constant So, p = C/r
• We know that axial loading acting on the ring is,
• Integrating above equation within limits we get,
rCW
rr
r
CrrpW


2
22


   
 21
21
0
2
22
2
1
2
1
2
RR
W
C
RRCrCW
rCW
R
R
R
R
W



 




18. • We know that, frictional torque acting on the ring is,
 
 2
2
2
1
2
2
2
1
0
0
2
2
2
2
2
2
22
2
1
2
1
2
RRCT
RR
CT
rrCT
rCrT
rCrrrT
rprT
R
R
T
r
R
R
T
r
r
C
r
r















• Torque transmitted by single plate clutch can be obtained by
integrating the equation within the limits R2 to R1 we get,

19. • This is the torque transmitted by single plate clutch due to friction
considering uniform wear theory.
• Power transmitted by single plate clutch is given by,
• Where, N = Speed of driving shaft
 
   
 
 
  
 
 212
1
21
2121
2
1
21
2
2
2
1
2
1
21
2
2
2
1
21 2
C
2
RRWT
RR
RRRR
W
RR
RR
WT
RR
W
RR
RR
W
T




















 
60
2 NT
P
Tp



