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Multi Plate Clutch: Diagram, Parts, Working and Uses [PDF]

In this article, you’ll learn what is multi plate clutch? Its diagram, parts, working, advantages, and applications all are explained with pictures.

Also, you can download the PDF file at the end of this article.

What is a Multi Plate Clutch?

In the transmission system, Multi-Plate Clutches are used for transferring power from the engine shaft to the transmission or driven shaft for the output to be turned at the required torque or speed. In automobiles, these are used when a high torque output is needed.

For high torque output, such as in pickup trucks, a multi-plate clutch is required; a single-plate clutch will not be able to produce that level of frictional force between the flywheel and clutch plates. The term “Multi-Plate Clutch” refers to a clutch that has multiple clutch plates, whereas a “Single Plate Clutch” has just one clutch plate.

A multi-plate clutch compensates for torque losses caused by slippage while at the same time transferring more power from the engine to the transmission shaft. Heavy machinery, commercial vehicles, special-purpose military vehicles, racing cars, and motorcycles all use this clutch.

Read Also: What is a Clutch? Parts, Function, Working, Applications & More

Parts of Multi Plate Clutch

The following are the main parts of the multi-plate clutch:

  1. Pressure plate
  2. Clutch plate
  3. Thrust springs
  4. Clutch pedal
  5. Clutch spring
  6. Splined shaft and splined sleeves
  7. Flywheel
  8. Diaphragm spring
  9. Fulcrum pin
  10. Bearing
Parts of Multi Plate Clutch

#1 Pressure Plate

To allow for back-and-forth movement, the pressure plate is mounted on a splined shaft. The clutch pedal regulates the sliding of the friction discs, which are bolted to the pressure plate.

#2 Clutch Plate

A clutch plate is a metallic plate with external frictional lines. Making frictional contact with the flywheel greatly helps in power transmission between the engine shaft and the transmission shaft.

#3 Thrust Springs

The thrust springs are used behind the pressure plate. The pressure plate maintains frictional contact with the clutch plates using the stiffness of these springs, which encourages clutch engagement.

#4 Clutch Pedal

A clutch pressure plate and a clutch pedal work together to modulate the clutch mechanism. The vehicle’s driver uses a clutch pedal to engage and disengage the clutch.

#5 Clutch Spring

It is used to store the torque energy and release it when needed, as well as to engage or disengage the clutch mechanism. There are two different kinds of clutch springs: coil clutch springs and tension clutch springs.

#6 Splined Shaft & Splined Sleeves

The entire clutch assembly is fixed to an external gearbox input shaft with splines. This system rotates with it and is made up of the clutch plates, pressure plate, inner splined sleeve, and clutch casing.

#7 Flywheel

The flywheel is an essential component of the clutch system and the engine. The clutch and the engine’s flywheel come into frictional contact to transmit power from the engine’s output shaft to the transmission shaft. It transfers power that has been generated from one shaft to another shaft.

#8 Diaphragm Spring

Compared to spring-type clutches, diaphragm-type clutches use a single diaphragm spring instead of thrust springs.

#9 Fulcrum Pin

There is a lever on top of the clutch pedal that is pivoted on a fulcrum pin and is used as a means of transmitting motion from the pedal to the pressure plate, once the clutch pedal has been pressed by the driver to disengage the clutch.

#10 Bearing

During the pedal mechanism’s rotating motion, the bearing transfers the pedal force from the stationary linkage to the rotating clutch.

Read Also: Understand The Working Principle of Air Brake System

Working of Multi Plate Clutch

This clutch has two different work processes that it can use: one is an appealing process, and the other is disruptive. Here we discuss two different kinds in relation to this:

#1 Engagement

In this instance, the clutch is typically engaged position. The clutch drum, which is further connected to the engine shaft, holds the friction plates in place. There are steel plates mounted on a hub that connects to the gearbox shaft, and they are secured by screws.

Therefore, it is necessary to hold the friction plate and steel plate together in order to transfer power from the engine shaft to the gearbox shaft. A pressure plate typically performs this task.

Through the use of a thrust spring, the pressure plate secures both varieties of plates. Power is thus transferred from the engine to the gearbox through the rotation of the friction plate and steel plates as a single unit.

#2 Disengagement

An operator must depress the clutch pedal to disengage the clutch. When the clutch pedal is depressed, the pressure plate is immediately moved backward. By doing so, pressure is released on the steel plate and friction plate set.

At this point, the frictional contact between these two plates has loosened. As a result, it disengages the gearbox shaft from the engine shaft. This state is referred to as a disengaged condition.

Now, if the pedal is released once more, the thrust spring will push the pressure plate against the friction plates once more, engaging the clutch.

Read Also: Understand the Working Principle of Leaf Spring Suspension

Types of Multi Plate Clutch

Following are the types of multi-plate clutch:

  1. Spring multi-plate clutch
  2. Diaphragm multi-plate clutch
  3. Hydraulic or automatic transmission clutch
  4. Wet multi-plate clutch
  5. Dry multi-plate clutch

#1 Spring Multi-plate Clutch

A cover is fastened to the engine’s flywheel in a spring-type multi-plate clutch. Numerous clutch plates are present on the cover. During clutch operation, clutch springs or thrust springs apply thrust on the inner plates, causing the plates to engage and form a drive.

The mechanism pulls back the endplate to release the clutch, compressing the springs and releasing the other plates. These multi-plate clutches are common in classic cars and motorcycles.

#2 Diaphragm Multi-plate Clutch

Instead of a thrust spring, the diaphragm-type clutch uses a diaphragm spring to push the pressure plate and engage the clutch. Because it is constructed of a specific finger-type spring in the shape of a crown, the diaphragm clutch got its name.

When the clutch is engaged, the diaphragm pushes against the outer ring, while when the clutch is disengaged, the inner ring carries the response load. Modern cars and motorcycles both use this type of clutch.

#3 Hydraulic or Automatic Transmission Clutch

In emerging automobiles with automatic transmissions, a hydraulic-operated clutch is used. The clutch is engaged and disengaged in this type of clutch using hydraulic devices rather than springs. This hydraulic device, which is used in automatic transmissions, contains highly compressed liquid and is operated by an accelerator pedal.

#4 Wet Clutch

Wet clutches typically have a lot of clutch plates and a lot of oil to cool and lubricate the parts. They can withstand much higher torque inputs because they are enhanced. When compared to dry clutches, wet clutches are frequently smaller.

They are used in situations with high torque where there would be a lot of friction and, as a result, a lot of friction would cause the clutch temperature to rise. Wet clutches have significantly less wear and tear than dry clutches and make less noise than dry clutches.

#5 Dry Clutch

The dry clutch relies on friction to operate rather than any liquid (oil). Due to the friction’s ability to heat the friction plate, dry clutches are typically larger to increase the friction plate’s surface area and facilitate effective air cooling.

With a dry clutch, the noise increases as the clutch wears down. In a dry clutch, power is transferred between two plates by a single frictional surface. As a result, their coefficient of friction is not noticeably lower.

Read Also: Understand the Different Types of Clutches Used in Cars

Advantages of Multi Plate Clutch

  1. The torque transmission capacity is significantly higher in multi-plate clutches because they contain more clutch plates.
  2. The larger friction surface causes the clutch assembly’s size to decrease along with its diameter.
  3. The multi-plate clutch is appropriate for any kind of vehicle worldwide because of its small size. 
  4. A multi-plate clutch can transmit more torque than a single-plate clutch because the torque transmission depends on the number of friction surfaces.
  5. In the case of heavy vehicles, which are primarily used for commercial purposes, a multi-plate clutch can be used easily due to the benefit of a high torque rate.
  6. The multi-plate clutch aids the engine in accelerating more quickly than a single-plate clutch would.
  7. A multi-plate clutch requires less pedal pressure to operate.

Disadvantages of Multi Plate Clutch

  1. A multi-plate clutch cannot be used continuously due to its heavy weight.
  2. Both the purchase price and ongoing maintenance costs of a multi-plate clutch are very high. 
  3. Because there are more friction surfaces than there are in a single-plate clutch, more heat can also be produced.
  4. The engine quickly warms up as a result of too much heat. In this situation, a cooling medium is necessary. Therefore, users must pay extra for the cooling medium.
  5. The size and weight of multi-plate clutches are massive.

Read Also: What is a Hydraulic Braking System? Parts, Working, Types & Uses

Application of Multi Plate Clutch

  1. When there is a limited amount of space available, such as in scooters and motorcycles, multi-plate clutches are used.
  2. Multi-plate wet clutches are employed in Two-Wheelers with restricted space.
  3. Additionally, it is used in racing cars to ensure maximum torque transmission.
  4. Automobiles like Heavy Transport and Special Purpose Vehicles also contain it.
  5. Large vehicles use it to transmit powerful torques when a single plate clutch of the same size is insufficient.
  6. Heavy-duty transport vehicles like tractor-trailers use multi-plate dry clutches because they have higher power and torque demands.

Read Also: Everything You Need To Know About Manual Transmission

Why a Multi Plate Clutch is Needed?

Image: Amazon.com

In high-performance and heavy-duty vehicles, multi-plate clutches are used to transmit large amounts of torque from the engine to the transmission. Compared to single-plate clutches, they have a higher torque capacity and offer smoother, more accurate engagement.

These clutches are better able to distribute torque load and reduce the risk of slipping because they provide more friction surface area. There is also the option of designing multi-plate clutches with different clutch plate configurations to optimize clutch performance for specific applications, which will improve clutch modulation and provide better clutch control.

Difference Between Single-Plate Clutch and Multi-Plate Clutch

There are two different kinds of clutch systems used in automobiles to transmit torque from the engine to the transmission: single-plate clutches and multi-plate clutches. The main difference between these two clutches are as follows:

#1 Number of Clutch Plates

These clutches have several clutch plates stacked together, whereas single-plate clutches only have one clutch plate.

#2 Torque Capacity

Due to the larger friction surface area provided by the multiple plates, multi-plate clutches can handle more torque than single-plate clutches.

#3 Clutch Engagement

While single-plate clutches can be less precise and smooth, multi-plate clutches can be better engaged with a smoother and more precise engagement.

#4 Clutch Control

Because they can be made with various plate configurations to optimize clutch behavior for particular applications, multi-plate clutches offer better modulation and control.

Vehicles with higher performance and heavier loads are typically fitted with multi-plate clutches, while lighter vehicles and applications with lower torque requirements use single-plate clutches.

Wrapping It Up

So now, I expect I’ve covered everything about this article. If you still have any doubts or questions on this topic, you can contact us or ask in the comments. If you like this article, then please share it with your friends.

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About Yousef

He is a mechanical engineering student, he likes to write about engineering stuff and he is really interested in learning about new technology in machines.

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