Definition : Clutch is a device transmission system of a vehicle to transmit the rotary motion of one shaft when desired to second shaft of which axis are coincident with that of first. Thus, the clutch is located between the engine and the transmission system.
Q. What is clutch ? state function and classification of friction clutch ?
Q. State the function of clutch ?
● When the clutch is engaged, power (Torque) transmit from the engine to the driving wheel through the transmission system and the vehicle moves. When the clutch disengaged, the power is not transmitted to the driving wheel and the vehicle stop, while the engine is still running.
● In vehicle, the clutch is always in the engaged position. The clutch is disengaged during the gear shifting, while stopping the vehicle or during braking and when idling the engine. It should be disengage by operating the clutch pedal.
● When clutch operated properly it prevents sudden jerk motion of the vehicle and this avoid putting under strain on the remaining part of the power transmission.
● The clutch is located just behind the engine, between the engine and the transmission.
Requirement of Clutch :
The main requirement of clutch are as follows :
1. It should be able to transmit maximum torque of the engine.
2. It should be engaged gradually to avoid sudden jerk aur shocks.
3. It should be able to dissipate large amount of heat generated during clutch operation.
4. It should be dynamically balanced for high speed engine.
5. It should have suitable mechanism for damp vibration and reduce noise during power transmission.
6. Size should be small and occupies less space.
7. Easy for operating so that it can operate by small effort of driver.
8. It should be lighter in weight.
Working principle of clutch :
● A clutch is a mechanism used to transmit the rotating motion of one shaft to another when desired and the axis of both the shaft are coincident.
● It works on the principle of friction. It connect the engine shaft and gearbox shaft. The transmission of power can be affected by friction between two or more rotating concentric surface, called as friction plate. The friction plate can be pressed firmly against one another by means of axial force provided by Spring and the pressure plate.
● When it engaged, the clutch tends to rotate as a single unit. The rotating speed of the concentric surface or other shaft is depend upon the friction force which is proportional to axial force applied by spring. The torque (power) transmitted by clutch is given by
T = WR
● Hence power transmitted by clutch is depend upon the coefficient of friction of the material and radius of clutch plate.
Function of clutch :
Q.State purpose and function of clutch in automobile ?
1. To permit engagement and disengagement of gear when the vehicle is stationary and the engine is running.
2. To transmit the engine power to the road wheel smoothly without shocks to the transmission system while setting in the vehicle in motion.
3. To permit the engaging of the gear when the vehicle is in motion without damping the gear wheel.
Design Consideration of Friction Clutch :
1. The suitable material forming the contact surface should be selected.
2. The moving part of the clutch should have low weight in order to minimise the inertia load, especially in high speed service.
3. The clutch should not require any external force to maintain contact of the frictional surface.
4. The clutch should have provision for facilitating repair.
5. The clutch should have provision for carrying away the heat generated at contact surface.
6. The provision for taking up wear of contact surface must be provided.
Selection of Clutch :
Q. The factor taken into consideration for deciding type of clutch are listed below :
1. Torque : Required normal force, type of friction surface and number of surface.
2. Rotation speed : It should be light compact and internally balanced.
3. Available space : Diameter and height of clutch.
4. Frequency of operation : Type of journey as small travel,a simple engagement mechanism, large cooling area, Low inertia.
