IJSRD - International Journal for Scientific Research & Development| Vol.
5, Issue 04, 2017 | ISSN (online): 2321-0613
Theoretical Calculation and Design of a Single Plate Clutch Use in
Automobile
B. R. Valiya
Lecturer
Department of Mechanical Engineering
S. B. Polytechnic (KJ Campus), Savli, India
Abstract— In design of the friction clutches of automobiles, Diaphragm type clutch.
knowledge on the thermo-elasticity a property is very Multiplate clutch.
informative in the initial design stage. Especially, the precise Helical type single plate clutch.
prediction technique of maximum structural stress should be Centrifugal clutch.
requested in design of mechanical clutches for their durability Cone clutch.
and compactness. In this study, an efficient and reliable
analysis technique for the design of the mechanical clutches D. Single Plate Friction Clutch
by using computer modeling and numerical method is The parts of a single plate clutch can be seen below. It has
developed. This work contains stress analysis of single plate only one clutch plate, mounted on the splines of the clutch
clutch of the automobile, in which the stresses and forces shaft. This is the most commonly used type. The Flywheel is
developed in the clutch is tried to reduce with the help of mounted on the crankshaft, and rotates with it. The pressure
software approach. The detail study of clutch and modeling plate is fixed on the flywheel through the pressure plate is
of clutch is done in pro-e software and the analysis is to be fixed on the flywheel through the clutch springs. The plate
done in Analysis software. rotates freely on the clutch shaft. It can also be moved axially
Key words: Design of a Single Plate Clutch, Single Plate along the clutch shaft. The axial movement of the pressure
Clutch plate is effected by pressing the clutch pedal. The end of the
clutch shaft rests and rotates freely in the pilot bearing housed
I. INTRODUCTION at the center of the flywheel.
Clutch is a device used in the transmission system of a vehicle
to engage and disengage the transmission system from the
engine. Thus, the clutch is located between the engine and the
transmission system. In a vehicle, the clutch is always in the
engaged position. The clutch is disengaged when starting the
engine, when shifting gears, when stopping the vehicle and
when idling the engine. It is disengaged by operating the
clutch pedal i.e. by pressing the pedal towards the floor of the
vehicle. The clutch is engaged when the vehicle has to move
Fig. 1: Clutch Plates in Automobiles
and is kept in the engaged position when the vehicle is
Clutch plate in a car is controlled by the left-most
moving. The clutch also permits the gradual taking up of the
pedal. This makes use of hydraulics or a cable connection.
load, when properly operated; it prevents jerky motion of the
The clutch may be physically located in close proximity to
vehicle and thus avoids putting undue strain on the remaining
the pedal, but remote means of actuation are required to
parts of the power transmission.
remove the effect of slight engine movement. If there is no
A. Clutch pressure on the pedal, it means that the clutch plates are
Clutch is a mechanism which enables the rotary motion of engaged. It gets disengaged once the clutch pedal is
one shaft to be transmitted, when desired, to a second shaft depressed. Cars can also function with manual transmission.
the axis of which is coincident with that of the first In this there are cogs that have matching teeth to synchronize
the speed. One can select gears with the help of these cogs. In
B. Function of Clutch motorcycles, the clutch is operated by the clutch lever. One
Clutch is use the function of clutch to engage and disen- can engage the clutch plate by applying no pressure on the
gage the engine power from gear box or wheel. lever. Pulling the lever back towards the rider disengages the
Effortless operation. clutch plates. Slipper clutch plates are often used by racing
Minimum size. motorcycles to get rid of engine braking.
Minimum mass. E. Operating of Single Plate Clutch
Torque transmission will be more. A single plate clutch consists of a clutch plate whose both
Friction capacity will be more. sides are faced with a frictional material. It is mounted on the
Heat dissipation will be more. hub which is free to move axially along the spline of the
Minimum vibration. driven shaft. The pressure plate and flywheel rotate with the
Well balance. engine crankshaft or driving shaft. The pressure plate pushes
C. Types of Clutch the clutch plate towards the flywheel by a set of strong springs
which are arranged radially inside the body. When the clutch
Single plate clutch. is engaged, the power is flows from the engine to the rear
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Theoretical Calculation and Design of a Single Plate Clutch Use in Automobile
(IJSRD/Vol. 5/Issue 04/2017/271)
wheels through the transmission system and the vehicle External diameter= 200mm
moves. When the clutch is disengaged, the power is not Width=9mm
transmitted to the rear wheels and the vehicle stops while the
engine is still running. The clutch is disengaged when starting D. Flywheel
the engine, when shifting the gears, when stopping the vehicle External diameter= 250mm
and when idling the engine. The clutch permits the gradual No. of teeth=122
taking up of the load. It prevents jerky motion of the vehicle.
E. Spring
The axial pressure exerted by the spring provides a frictional
force in the circumferential direction when the relative Length=30mm
motion between the driving and driven members tends to Outer diameter = 15mm
takes place. If the torque due to this frictional force exceeds Inner diameter= 13mm
the torque to be transmitted, then no slipping takes place and
F. Release Bearing
the power is transmitted from the driving shaft to the driven
shaft. Figure 2 shows the main parts of clutch system. Outer diameter=40mm
Inner diameter-30mm
Hook distance=75mm
G. Calculations
Outer diameter (Do) = 200 mm
Inner diameter (D1 = 150 mm
No. of spring = 9 μ = 0.35
R1/ R0 = 100/115 = 0.869
Fa = 9X625 = 5.625 KN
Torque Capacity of New Clutch (T)
= 363.401 N-m = 0.363401kN-m
Fig. 2: The main parts of clutch system Torque Capacity after Initial Wear,
T = uFaDmNf/2
II. STRUCTURAL ANALYSIS = 0.3X5625X (230+200/2) X2 / 2
Structural analysis comprises the set of physical laws and = 362.81 N-m
mathematics required to study and predicts the behavior of Safety Factor when New= T / 124 = 363.401/124 = 2.930
structures. The subjects of structural analysis are engineering Safety Factor after initial wear = 362.810/124 =2.925
artifacts whose integrity is judged largely based upon their Reduction in clamping force so that Slippage Occurs,
ability to withstand loads; they commonly include buildings, New Clamping Force
bridges, aircraft, and ships. Structural analysis incorporates Fa1= 5.625X103 X 124/ 362.81 = 1.9224 KN
the fields of mechanics and dynamics as well as the many Change in Clamping Force,
failure theories. From a theoretical perspective the primary Fa= 5.625-1.9224 = 3.703 KN
goal of structural analysis is the computation of deformations, Change in Clamping Force of each spring,
internal forces, and stresses. In practice, structural analysis = 3.703/4 = 0.9257 KN
can be viewed more abstractly as a method to drive the Spring Stiffness = 625/6.5
engineering design process or prove the soundness of a design = 96.15 N/mm Required Wear
without a dependence on directly testing it. = 925.7 / 96.15
It includes the following methods, = 6.928mm
Analytical Methods 1) For design of spring
Strength of materials methods (classical methods) Max. Force = 625X1.1 = 687.5 N (10% extra force for
Finite element methods (FEM) Modeling of Clutch disengagement)
Spring stiffness = 96 N/mm
A. Specification
For automotive clutch springs,
Model- TATA 475 IDITC Select Cr-V Steel SAE.6150
Maximum power - 51.5 kW @4800rpm Allowable Shear Stress with a F.S. = 1.2τmax = Sys
Maximum torque- 124 Nm @ 2800rpm / 1.2
Capacity-1405cc Sys = 770
B. Pressure Plate τmax = 770 / 1.2 = 641Mpa
Assuming Wahl Factor, C= 6
Internal diameter = 150mm K= ((4X6 -1) / (4X6 -4)) + (0.615/6) = 1.25
Pressure plate Outer diameter = 200mm τmax= 8Fmax.DmK/πd3 = 8FCK/πd2
Rim diameter= 25mm = 8X687.5X6X1.25/πd3 = 513
C. Clutch Plate d = 5.06 = 5mm (say)
Material: Structural steel Dm = 5X6 = 30mm
To find the no. of turns,
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Theoretical Calculation and Design of a Single Plate Clutch Use in Automobile
(IJSRD/Vol. 5/Issue 04/2017/271)
Ks = 96 = Gd / 8C2n
G = 85X103
n = (85X103X5) / (8X63X96) = 2.56
Total No. of turns with Squared and Ground ends, =
2.56+2 = 4.56 = 5 (say)
Free length = 5X5 + 687.5/96 + 4 = 36.16mm
Free length/ Dm = 36.16 / 30 = 1.2, so ok
To check whether nine springs can be accommodated.
Mean Diameter of the Friction Disc = (230+200) / 2
Space available/ spring = π X 215 / 4 = 168.86 mm
Do of spring = Dm + d = 30+5 = 35mm, so ok
III. CONCLUSION
After completion of the theoretical calculation based on the
values of Equivalent stresses for material loading conditions
it is clearly seen that these are less than the allowable stresses
for that particular material under applied conditions the part
not going to yield and hence the design is safe.
The result occurred are quiet favorable which was
expected. The stresses as well as deformation clear the idea
about what parameter should have been taken into account
while defining the single plate friction clutch.
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