What is Multi Plate Clutch?
The Multi Plate Clutch uses multiple clutch plates to make contact with the engine flywheel to transfer power between the engine shaft and the transmission shaft. A multi-plate clutch used in automobiles and machinery where high torque output is required.
It is a type of clutch that transmits more power from the engine to the transmission shaft of an automobile vehicle and also, makes up for the torque loss due to slippage. Multiple clutches consist of more than three discs or plates so that they can provide more torque output.
Multi-plate clutches are used in heavy vehicles with racing cars and motorcycles for transmitting high torque. As compared to single plate clutches, these are smooth and easy to operate due to their assembly of friction surface’s contact. It may be used where the space is very limited.
Read: What is a Single plate Clutch?
Multi-Plate Clutch Diagram
Parts of Multi Plate Clutch
The components of all the clutches used in automobile vehicles are almost the same. But with some modifications, so let’s discuss the main parts of different types of multi-plate clasps used.
- Pressure Plate: A plate attached to the splined sleeves which further connected to the pedal fulcrum. Such that when the clutch pedal pressed, the sleeves attached to the pedal fulcrum move outward, which in turn drives the pressure plate attached with this splined sleeve.
- Clutch Plate: It is a metallic plate having frictional lines at its outer surfaces. It uses frictional contact with the flywheel to transmit power between the engine shaft and the transmission shaft.
- Thrust Springs: These are springs used behind the pressure plate, and the stiffness of these springs is used by the pressure plate to maintain frictional contact with clutch plates, which in turn supports the clutch engagement.
- Clutch Pedal: A clutch pedal operated by the driver of the vehicle used to control the engagement and disengagement of the clutch.
- Splined Shaft & Inner Splined Sleeves: An outer splined transmission input shaft over which the complete clutch assembly. That includes clutch plates, pressure plates, inner splined sleeve, the clutch casing place and rotates with it.
- Flywheel: It is part of the engine. We can also consider it as part of the clutch system as the transmission of power from the engine output shaft to the transmission shaft obtain by the frictional contact between a clutch and the flywheel of an engine.
- Diaphragm Spring: In the diaphragm type clutch system, the thrust springs used in the spring type clutch replace with a single diaphragm type spring.
Construction of Multi Plate Clutch:
The multi-plate clutches construction is similar to a single plate clutches except for the number of clutches plates. The total number of clutch plates divides into two sets in which one from each set is alternatively arranged.
One set of the plate slides in grooves on the flywheel and the other one slides on splines on the pressure plate hub. These plates are reliably pressed by a strong coil spring and assembled in a drum.
A Multi-Plate clutch works in the same way as the single-plate clutch by operating the clutch pedal.
As the number of clutch plates increases, the friction surfaces will also be increases. The increase in friction surface increases the capacity of the clutch to transmit more torque for the same size.
The multi-plate clutches of small size transmit approximately the same torque as single-plate clutches of twice the diameter.
Working of Multi Plate Clutch
Engagement of Clutch
- During the engaged position of the clutch, i.e., when the clutch pedal is not pressed.
- The thrust springs do not move due to which the stiffness provided by these springs maintains the pressure over the pressure, the plate having friction lines on its inner surface.
- Due to this pressure over the pressure surface, the frictional contact between the friction lines of the pressure plate and the friction lines of multiple clutch plates is maintained due to which frictional force is applied over the flywheel.
- Due to this frictional force, the frictional contact between the various clutch plates and the wheel is supported, which in turn finally provides clutch engagement.
Disengagement of Clutch
- When the clutch pedal is pressed, the fulcrum attached at its inner end rotates due to which the inner splined sleeve through which the pressure plate connects moves outward, which in turn applies pressure over the thrust springs.
- Due to this force, the thrust springs move, which in turn releases the tension over the pressure plate, and finally, the frictional force between the pressure plate, clutch plate, and flywheel is removed.
- For the reason that the removal of the frictional force, frictional contact between the pressure plate, clutch plate, and flywheel breaks, and finally the disengagement of the clutch obtained.
Types of Multi-Plate Clutch
These are various types of Multi-plate Clutches
- Spring Type Multi Plate Clutch
- Diaphragm Type Multi Plate Clutch
- Hydraulic-operated or Automatic Transmission Clutch
- Wet Multi Plate Clutch
- Dry Multi Plate Clutch
1. Spring Type Multi Plate Clutch
Spring Type Multi-Plates Clutching the clutch, a cover attaches with a flywheel of engine use inside which the multiple clutch plates, pressure plates, thrust bearing, etc. packed. The clutch plates place over each other and mount over a splined shaft.
2. Diaphragm Type Multi Plate Clutch
It is the modified version of the spring-type multi-plates clutch. In which the thrust springs places circularly from the spring-type clutch replace with a special crown-shape finger type spring called a diaphragm spring.
3. Hydraulic-operated or Automatic Transmission Clutch
It is the modern type of clutches uses in vehicles fitted with automatic transmission, in this type of clutches a hydraulic device having highly compressed fluid operates with the accelerator pedal coupled with the multi-plate clutches.
The engagement and disengagement of the clutch obtained by the output given by the hydraulic device, which controls with the acceleration pedal.
4. Wet Multi Plate Clutch
Wet clutches, in general, have multiple clutch plates (in cars) and have a supply of oil to lubricate and cool the components. This type of clutch is located inside the engine casing.
The wet clutches are greatly amplified and therefore can cope with much higher torque inputs. Wet clutches are generally smaller in size.
The noise level in wet clutches is less when compares to dry clutches. The presence of oil between plates helps in managing the noise.
Wear and tear are very much less in the wet clutch. In a wet clutch, the lubricating oil keeps surfaces clean and provides smoother performance and longer life.
Wet clutches provide a better coefficient of friction, as the surface area increases due to the presence of multiple plates.
5. Dry Multi Plate Clutch
A Dry Clutch is a type of clutch that is not bathed in liquid (oil) and uses friction to engage. This type of clutch has its plate outside the engine casing.
Usually, the dry clutch is larger to increase the surface area of the friction plate for optimal air cooling because it does get hot due to friction of the plate.
The level of noise in the dry clutch is more and keeps increasing as the clutch continues to undergo wear and tear.
Dry clutches have a single frictional surface to transmit the power between two plates. Therefore, they do not have a much better coefficient of friction.
In the dry clutch, the lubricant does not applies and hence the torque transmitting of these clutches is better. Dry clutches do not have an oil supply and are generally single-plate.
Application of Multi-Plate Clutch
- It can be used in industrial machines and automobiles where high performance is required.
- Due to the compact gearbox and high acceleration is required and the criteria for torque transfer are maximum, it can be used in motorcycle or drag racing races, as well as in F1 vehicles.
- Due to the compact gearbox design, it can be used in ships, trucks, and locomotives.
- It is suitable for heavy types of machines such as bulldozers, excavators, tanks and caterpillars, and others because the multi-disc clutch is heavy and produces high power. Because of this, the heavy machine parts easily lift heavyweights.
- The multi-plate lock is used in heavy commercial vehicles to transmit high torque.
- The multi-disc clutch is used where the required space in which the clutch has to be installed is much less than with motorcycles and scooters.
Advantages of Multi-Plate Clutch
- Since the multi-plate clutches consist of more clutch plates, the ability to transmit the torque is quite high.
- This type of clutch is small. Due to its compact size, the multi-disc clutch is suitable for all types of vehicles around the globe. Since the motorcycles and scooters only have limited space, the multi-plate clutch can be easily installed due to its compact size.
- Compared to the single-disc clutch, the diameter of the multi-disc clutch is smaller than that of the single-disc clutch. Because of this function, the multi-disc clutch can be used in many sports such as racing and others.
- The multi-plate clutches have many friction surfaces. Since the torque transmission depends on the number of friction surfaces, the torque is higher with the multi-disc clutch than with the single-disc clutch.
- Because of the advantage of a higher torque rate, the multi-plate clutches can easily be used in heavy vehicles which are mainly used for commercial purposes.
- Compared to a single-disc clutch, the multi-disc clutch helps the engine achieve better acceleration.
- A force is required to depress the clutch pedal to make the clutch operational. Less pedal force is required to operate a multi-plate clutch.
Disadvantages of Multi-Plate Clutch
- The weight of the multi-plate clutch is heavy and therefore not suitable for all-time use.
- The cost of the multi-plate clutch, along with its maintenance work, is very high. So it is not good for multi-plate clutch users on a budget.
- Users have to spend additional money on the cooling medium. Because of this disadvantage, the maintenance cost automatically becomes high.
- They heat up quickly.
- Multi-plate clutches are heavy.
- Multi-plate clutches are too expensive.