Diaphragm clutch: Definition, Principle, Parts, Diagram, Working, Application, Disadvantages Pdf

Hello Friends, Let’s learn about the Diaphragm Clutch. But before the start, let’s briefly understand about an Automobile Clutch.

An automobile clutch is a device that ensures smooth engagement and disengagement between the power transmitting shafts i.e. driving shaft and driven shaft.

The driver can easily shift gear or slow down the vehicle by pressing the clutch pedal. The pressing of the clutch pedal breaks the contact between driving and driven shafts which results in termination of power transmission from engine to the gearbox.

What is Diaphragm clutch?

  • Diaphragm clutch is one of the type of automobile clutch which uses the diaphragm spring for the engagement & disengagement of the clutch.
  • As compared to plate type clutch, In diaphragm clutch, Diaphragm spring is use at place of coil spring to keep axial force (Clamping force) on pressure plate.

Working principle:

Diaphragm clutch works on the Friction principle.

1] Friction is responsible For the power (Torque) transmission from Flywheel to Gearbox.

2] A Plate which having Friction lining on its surface is known as Friction Plate. The friction Plate is pressed onto the Flywheel under the axial force applied by pressure plate.

3] In Engaged Condition of Clutch, Flywheel, Friction Plate & Pressure plate are united due to Axial Force exerted by a Pressure plate.


It consists of friction plate/clutch plate, pressure plate, flywheel, diaphragm, release bearing, clutch pedal, release fork.

1) Pressure Plate:- This plate is used in the clutch to forces the friction plate onto the flywheel. The diaphragm spring is located on one side of the pressure plate.

2) Flywheel:- Flywheel is connected to the vehicle engine crankshaft and rotate with it. In running condition of the vehicle, the pressure plate forces the friction plate onto the flywheel, Due to frction between friction plate and flywheel, the power transmits from the flywheel to the output clutch shaft.

3) Diaphragm :- Diaphragm is one of the type of spring which has a circular shape. It helps to keep the pressure onto a friction plate. When release bearing presses the inside part of the spring, the outside part of spring moves outwards and presses the friction plate on flywheel.

4) Friction Plate:-This plate is generally located between the flywheel and pressure plate that has a friction material onto the surface of both sides. The friction material is responsible for power transmission when these plates are united during an engagement.

Diaphragm clutch

5) Release Fork:- The release fork performs work to presses the release bearing to press the Diaphragm spring. Release Fork is Connected to Clutch Pedal through Linkage.

6) Release Bearing:- It is bearing which operated by the release fork to press the diaphragm spring.

7) Clutch Pedal:- The clutch pedal is the pedal that is connected to the clutch and operated by the driver.

Diaphragm clutch working:

Let’s understand the working with the help of diaphragm clutch diagrams.


Diaphragm clutch

1] When driver press the clutch pedal through a linkages release fork presses the release bearing.

2] Due to release Fork presses the release bearing, Release Bearing presses the middle portion of the diaphragm to move inwards.

3] Due to inwards movement of middle portion of diaphragm, outside part of diaphragm moves backwards as well as pressure plate also moves backwards.

4] Therefore due to pressure plate backward movement, pressure on friction plate gets removes. So there is no friction between plates & flywheel. Hence no power transmission takes place.  Hence clutch gets Disengages.


Diaphragm clutch

1] When driver release the clutch pedal, results in diaphragm again comes to original position. 

2] Hence outside part of diaphragm moves inside & presses the pressure plate on friction plate & flywheel. Therefore friction occurs between them. Hence power/torque again starts transmits from flywheel to clutch shaft.  Hence Clutch gets Engages.

Diaphragm clutch video:

Diaphragm clutch advantages and disadvantages:

Diaphragm clutch advantages:-

  1. It is lighter in weight.
  2. It has compact size.
  3. Diaphragm spring applies more force hence the it has higher torque transmission capacity.
  4. It has less rotating parts hence no problem of noisy working.
  5. It has dynamic balancing even at high speed.

Diaphragm clutch disadvantages:-

For heavy vehicles, the size of the clutch becomes higher for increasing friction surfaces.

Diaphragm clutch application:

The diaphragm clutch has following applications:-

  1. Maruri suzuki swift
  2. Tata safari storme
  3. Ford Ecosport
  4. Nissan navara


  1. What is diaphragm clutch ?

    Diaphragm clutch is one of the type of automobile clutch in which diaphragm spring is used for engagement and disengagement.

  2. How does a diaphragm clutch work ?

    When driver press the clutch pedal, diaphragm moves backward therefore pressure on flywheel and friction plate gets removes, Hence no power transmits, in such way clutch disengages.

    When driver release the clutch pedal, diaphragm again pressed on the friction plate and flywheel, power transmission starts in such way clutch engages.

  3. What is a diaphragm spring clutch?

    Diaphragm spring clutch is one of the type of automobile clutch in which diaphragm spring is used for engagement and disengagement.

  4. What are the advantages of diaphragm clutch?

    The diaphragm clutch has following advantages :- It is lighter in weight, It has dynamic balancing even at high speed.

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Media credits:

Pratik is a Graduated Mechanical engineer. He enjoys sharing the engineering knowledge learned by him with people.

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