What is a Clutch in the Car? & Types of clutches


The clutch is a mechanical device that specifically engages and disengages the power transmission from the driving shaft to the driven shaft. In clutch one shaft is usually connected to an engine or another power unit while the other shaft provides output power for the work.

The clutch used in a motor vehicle is almost very similar in construction and operation. There are some differences in the details of the linkage as well as in the pressure plate assemblies. The various types of clutches used in the automobile depend upon the clutch types and use of friction.

A clutch is cists of a flywheel, clutch disc, intermediate plate, and clutch cover. Clutches use several coil springs but some use a diaphragm or conical type spring. The type of friction materials also varies in the clutches of different passenger cars.

Types of clutches that are used in automobile industries:

  1. Friction clutch
  2. Single plate clutch
  3. Multi-plate clutch
  4. Cone clutch
  5. Centrifugal clutch
  6. Semi-conductor clutch
  7. Conical spring or diaphragm clutch
  8. Positive clutch
  9. Hydraulic clutch
  10. Electromagnetic clutch
  11. Vacuum clutch
  12. Overrunning clutch or freewheel unit

Single plate clutch:

This is one of the most commonly used types of clutches and is used in most modern light vehicles. The clutch helps transmit torque from the engine to the transmission input shaft as the name states it has only one clutch plate.

It consists of a clutch plate, friction plate, pressure plate, flywheel, bearings, clutch spring, and nut bolts arrangement. The single plate clutch has only one plate which is attached to the splines of the clutch plate. It was one of the main components of the clutch.

The clutch plate is simply thin metallic discs and has both side friction surfaces. The flywheel is attached to the engine crankshaft and rotates with it. A pressure plate is bolted to the flywheel through a charged spring which provides the axial force to keep the clutch engaged position. It is free to slide on the clutch shaft when the clutch pedal is operated. In a vehicle, we operate the clutch by pressing the clutch to the pedal for this engagement of gears. Then springs get compressed and the pressure plate moves backward. Now the clutch plate becomes free between the pressure plate and fire wheel due to this the clutch is getting disengaged and able to shift the gear.

Multi-plate clutch:

In this clutch types there are multiple clutches are used to make frictional contact with a fire wheel of the engine this makes transmits power between the engine shaft and the transmission shaft of a vehicle. The number of clutches means more friction surface. The increased number of friction surfaces also increases the capacity of the clutch to transmit torque. The clutch plates are fitted to the engine shaft and gearbox shaft. Clutch plates are pressed by coil springs and assembled in a drum each of the alternate plates slides in grooves on the flywheel and the other slides on splines on the pressure plate hence each difference has an inner and outer spline. The multiple clutches are used in heavy commercial vehicles racing cars and motorcycles for transmitting high torque.

Cone clutch:

Cone clutches consist of friction surfaces in the form of cones. This clutch uses two conical surfaces to transmit torque by friction. The engine shaft consists of a female cone and a male cone. The male cone is mounted on the spline clutch shaft to slide on it. It has a friction surface on the conical portion. Due to the force of spring when the clutch is engaged the friction surfaces of the male cone are in contact with the female cone. When the clutch pedal is pressed the male cone slides towards the spring force and the clutch is disengaged.

Centrifugal clutch:

Centrifugal clutch to keep the clutches in the engage position. These clutches use centrifugal force instead of spring force in these types of clutches. The clutch is operated automatically depending upon the engine speed that’s why no clutch pedal is required to operate the clutch. It was made so easy for the driver to stop the vehicle in any gear without stalling the engine. Similarly, you can start the vehicle in any gear by pressing the accelerator pedal.

Semi-centrifugal clutch:

The semi-centrifugal clutch uses centrifugal force and spring force for keeping it in the engaged position. Semi-centrifugal clutch and clutch springs are arranged equally on the pressure plate. The springs of the clutch are designed to transmit the torque at normal engine speed while the centrifugal force helps in torque transmission at higher engine speed.

At normal engine speeds when the power transmission is low, the springs keep the clutch engaged the weighted levers do not have any pressure on the pressure plate. At high engine speed when the power transmission is high the weights fire off and the levers also exert pressure on the plate keeping the clutch firmly engaged.

Conical spring clutch or diaphragm clutch:

The diaphragm clutch consists of a diaphragm on a conical spring which produces pressure on the pressure plate for engaging the clutch. The spring may be a finger or crown type that is attached to the pressure plate. In these types of clutch, the engine power is transmitted from the crankshaft to the flywheel. The flywheel has friction lining and it is connected to the clutch. In a diaphragm clutch, the diaphragm is a conical shape of the spring when we press the clutch pedal the outside bearing moves towards the flywheel pressing the diaphragm spring which pushes the pressure plate backward. By doing this pressure on the plate removes and the clutch will get disengaged. When we release pressure on the clutch pedal, the pressure plate and diaphragm spring will come back to their normal position and the clutch will get engaged.

Dog and spline clutch:

The dog clutch types is used to lock two shafts together or to connect the error and shaft there are two parts of the clutch. One is a dog clutch which has external teeth and another one is a sliding sleeve which has internal teeth. Both shafts are designed in such a way that one will rotate another one at the same speed and will never slip. When the two shafts are connected then you can say the clutch is engaged to disengage the clutch. The sliding sleeves move back on the spline shaft to have no contact with the driving shaft. The Dorgon’s spline clutch is mostly used in manual transmission vehicles to log different years.

Electromagnetic clutch:

These types of clutches are operated electrically but the torque is transmitted mechanically this is why this type of clutch is known as an electromagnetic clutch. The electromagnetic clutch has a flywheel consisting of winding. The electricity is supplied by the battery when the electricity passes through the winding. It produces the electromagnetic field which causes to attract the pressure plate to get engaged. When the electricity supply is cut off, the clutch is disengaged. These clutches have no mechanical linkage to control their engagement that’s why it provides fast and smooth operation. The electromagnetic clutches are most suitable for the remote operation which means you can operate the clutch at a long distance.

Vacuum clutch:

The vacuum clutch uses the existing vacuum in the engine manifold to operate the clutch. The vacuum clutch consists of a reservoir, non-return valve, vacuum cylinder with piston, and solenoid valve.

Hydraulic clutch:

The hydraulic clutch is operated by oil pressure. It has fewer parts than other clutches that consist of an accumulator, control valve, cylinder with a piston pump, and reservoir.

Freewheel unit:

The freewheel unit clutch is also known as spring clutch, overrunning clutch, or one-way clutch. It is the most important part of every overdrive. The transmission of power is in one direction similar to bicycles. The freewheel is often mounted behind the gearbox.

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