GANDHINAGAR INSTITUTE OF TECHNOLOGY THEORY OF MACHINES
(2151902)Active Learning Assignment OnMECHANICAL DEPARTMENTFRICTIONAL CLUCHES PREPAIRED BY: MANAV SONANI (140120119223)
CHANDRESH SUTHAR (140120119229)
GOVIND TADE (140120119230)GUIDED BY:
PROF. VIPAL PANCHAL
Introduction to clutch Types of clutchDisc clutch
Single plate clutch Multi plate clutchCone clutchCentrifugal clutch
WHAT IS CLUTCHES ?AClutchis a mechanical device that engages and disengages the powertransmission , especially fromdriving shaftto driven shaft.
In the simplest application, clutches connect and disconnect two rotating shafts (drive shaftsorline shafts). In these devices, one shaft is typically attached to an engine or other power unit (the driving member) while the other shaft (the driven member) provides output power for work.
TYPES OF CLUTCHESMechanical clutchesPneumatic clutchesHydraulic clutchesElectromagnetic clutches
Mechanical clutches1)Positive contact clutches jaw clutchestoothed clutches2)Friction clutchesDisc clutches Single plate clutches Multi plate clutches Cone clutchesCentrifugal clutches
SINGLE PLATE CLUTCH
USED IN CARS AND LIGHT VEHICLES. IT HAS ONLY ONE CLUTCH PLATE WHICH IS MOUNTED ON THE SPLINES OF THE CLUTCH SHAFT.
WHEN CLUTCH IS IN ENGAGED POSITION, THE CLUTCH PLATE REMAINS GRIPPED BETWEEN FLYWHEEL AND PRESSURE PLATE. FRICTION LININGS ARE PROVIDED ON BOTH THE SIDES OF CLUTCH PLATE.
Single Plate ClutchW=total axial load
R1=External radius of clutch plate
R2=internal radius of the clutch plate
P=intensity of pressure between contacting surfaces.
=coefficient of friction between contacting surfaces
Single Plate ClutchConsider a elemental ring of radius r and thickness r on the contacting surface. therefore,Area of the ring on contacting surface is,
Axial load on the ring is, W=pressureArea of the ring
Single Plate ClutchFrictional resistance offered by ring is,
Frictional torque acting on the ring is,
Single Plate ClutchTorque transmitted by single plate clutch is obtained by considering following two assumptions
(a)uniform pressure theory (b)uniform wear theory
Single Plate Clutch(a)uniform pressure theory: Assuming that the intensity of pressure over the entire contacting surface area is constant,
Total torque transmitted by single plate clutch can be obtain by integrating Equation Then, p=constant
Single Plate Clutch(1)within limit R2 to R1 we[p=Constant]
.(A) Equation (A) gives the torque transmitted by single plate clutch due to friction considering uniform pressure theory.
Single Plate Clutch(b) Uniform Wear TheoryIn this theory, we are considering that wear which take place is uniform over the entire contacting surface i.e.
Single Plate ClutchAxial load acting on the ring is
W=p 2 r r W=2 C r (4)Integrating above Equation(4) within limit we get,
Single Plate Clutch
We know that frictional torque acting on ring is,.(5).(6)
Single Plate ClutchTorque transmitted by single plate clutch can be obtain by integrating the Equation (4 ) within the limit R2 to R1 we get,
Single Plate Clutch
This is the torque transmitted by single plate due to friction considering uniform wear theory.
Single Plate Clutch Power transmitted by single plate clutch is given by,
MULTIPLATE CLUTCHMulti-plate clutch consists of more than one clutch plates contrary to single plate clutch which consists of only one plate. Friction surfaces are made in case of multi-plate clutch. Due to increased number of friction surfaces, a multi-plate clutch can transmit large torque.
For multiplate clutchFor uniform pressure theory,
For uniform wear theory,
Multiplate Clutch Notes:In case of new clutch ,the intensity of pressure is uniform along the surface of clutch but in case of old clutch uniform theory is more correct.
For single plate clutch normally both sides of the plate are effective .there for single plate clutch has two pairs of contacting surface i.e. n=2.
In actual practice, usually the theory of uniform wear is used in analysis of clutch.
Intensity of pressure is maximum at the inner radius R2 of the friction or contact surface,
Intensity of pressure is minimum at the inner radius R1 of the friction or contact surface,
In mutilate disc clutch no of disc on driving shaft no of disc on driven shaft
So no. of pairs in contact,
CONE CLUTCHA cone clutch serves the same purpose as a disk or plate clutch. However, instead of mating two spinning disks, the cone clutch uses two conical surfaces to transmit friction and torque. The cone clutch transfers a higher torque than plate or disk clutches of the same size due to the wedging action and increased surface area.
CONE CLUTCHCone clutches are generally now only used in low peripheral speed applications although they were once common in automobiles and other combustion engine transmissions. They are usually now confined to very specialist transmissions in racing, rallying, or in extreme off-road vehicles, although they are common in power boats.
Notation of cone clutch
CONE CLUTCHAn element of cone clutch
CONE CLUTCHAccording to uniform pressure theory,
(where p is constant)
According to uniform wear theory,
(where p*r is constant)
CENTRIFUGAL CLUTCHA centrifugal clutch works on the principle of centrifugal force. The clutch's purpose is to disengage when the engine is idling so that the chain does not move .These clutches are particularly useful in internal combustion engines, which can not be started under load.
The clutch consists of three parts:
An outer drum that turns freely - This drum includes a sprocket that engages the chain. When the drum turns, the chain turns. A centre shaft attached directly to the engine's crankshaft - If the engine is turning, so is the shaft. A pair of cylindrical clutch weights attached to the centre shaft, along with a spring that keeps them retracted against the shaftCENTRIFUGAL CLUTCH
There are several advantages to a centrifugal clutch
It is automatic. (In a car with a manual transmission, you need a clutch pedal. A centrifugal clutch doesn't.) It slips automatically to avoid stalling the engine. (In a car, the driver must slip the clutch.) Once the engine is spinning fast enough, there is no slip in the clutch. It lasts forever. CENTRIFUGAL CLUTCH
CENTRIFUGAL CLUTCHThe centrifugal force acting on each shoe,
Just before engagement with shoe,
CENTRIFUGAL CLUTCHDuring running condition, the net force