A clutch is a mechanical device which engages and disengages power transmission from the engine to the gearbox of an automobile.

What is clutch | construction and working

A clutch is a part of the transmission system which receives power from the engine ( 4 stroke or 2 stroke ) via the Flywheel and transmits this power to the gearbox of the automobile to drive the wheels.

What is the need of a clutch?


Now let us take an example of a car. Imagine you are driving a car and you need to change gears, now if a clutch isn’t present you would have to stop the car let the engine come to rest and then change the gear or else the gears would get damaged if changed in motion.

This would be very hectic and impractical. So if a clutch was present you can disconnect the engine and the transmission and then change the gear without having to stop the car. This is why clutches are so important.

Types of clutches

  1. Plate or disc clutch (Single plate or multi plate)
  2. Cone clutch
  3. Centrifugal clutch
  4. Diaphragm clutch

Single Plate Clutch Construction and working :


This is the most common and widely used clutch in automobiles. The important components of single plate clutch are :

  • Flywheel
  • Clutch plate
  • Pressure plate
  • Clutch springs
  • Thrust bearing

Flywheel : 

Flywheel is a disc of heavy mass and bolted to the engine crankshaft. The flywheel is a flat disc and is in contact with the clutch plate or friction plate.



Clutch plate : 

Clutch plate is a metal disc with friction linings on both of of its surfaces. It has a central hub which is machined internally so that it can slide to and fro on a splined shaft.


Pressure Plate : 

It is a heavy mass plate which makes sure that the flywheel and the friction plate are in good contact of each other to ensure smooth power transmission.

Clutch springs : 

These springs are radially mounted over the pressure plate to ensure that the plates are in engaged position when the clutch pedal is at rest. When the clutch pedal is pressed by the driver these springs are compressed hence the clutch is disengaged.


Thrust bearing :

This bearing handles the axial load which comes during sudden release of the clutch springs. They help in dampening and provide seamless operation.

Working of the Single plate clutch:






When the clutch is in engaged position 


i.e. the clutch pedal is not pressed by the driver. This condition is refered as clutch pedal position-up. When the pedal position is up, the actual force applied by the clutch springs causes the flywheel, friction plate and pressure plate to be sandwiched together.

Thus, the drive is engaged and power is transmitted from the engine to the transmission system (gearbox) and hence the wheels of th car move forward.

When the clutch is in disengaged position.


In this position the driver presses the clutch-pedal. This causes the pressure plate to overcome the force of the springs. Due to this the contact between the pressure plate and flywheel is loosen up.

Therefore, the drive gets disengaged and power is not transmitted from the engine to the transmission system (gearbox).


Applications of single plate clutch :

  1. It is used in Buses,
  2. Cars
  3. Jeeps
  4. Trucks and similar heavy weight vehicle's transmission systems.
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