Single Plate Clutch: Diagram, Working & Application

What is a Single Plate Clutch?

Single plate clutch is the most common type of clutch plate used in automobiles. It consists of only one clutch plate which is mounted on the splines of the clutch plate. The Flywheel is mounted on the engine crankshaft and rotates with it.

The clutch primarily consists of two members, one mounted on the driving shaft and the other on the driven shaft.

These two shafts are parallel and concentric with each other; one shaft is fixed to its housing while the other is splined so that it can move axially. The driving torque can increase by increasing the effective radius of contact.

Working Of Single Plate Clutch

When the engine is running and therefore the flywheel is rotating, the pressure plate also rotates because the pressure plate attaches to the flywheel. The friction disc is located between the flywheel and the pressure plate. When the driving force has pushed down the clutch is released.

The pressure plate is bolted to the flywheel through clutch springs and is free to slide (Move) on the clutch shaft when the clutch pedal is operated (Engage and Disengage).

If Clutch Engaged

  • When the clutch is engaged (which Means when you not pressed the clutch pedal), the clutch plate is held between the flywheel and the pressure plate.
  • The friction linings are on both sides of the clutch plate. The clutch disc rotates the flywheel due to the friction between the flywheel, the clutch disc, and the pressure plate.
  • The clutch shaft also rotates with the clutch plate. The clutch shaft is connected to the gearbox. Now the engine power is transferred to the crankshaft and then to the clutch shaft and gearbox.
  • Clutch always engaged because of the spring forces.

If Clutch Disengaged

  • When the clutch is disengaged (which Means when you pressed the clutch pedal), the pressure plate moves back against the force of the springs, and the clutch plate is released between the flywheel and the pressure plate.
  • The flywheel always rotates with the crankshaft. Then the speed of the clutch shaft will slowly decrease and stop rotating.

Single plate clutch diagram

Single plate clutch
Diagram of single plate clutch

Parts of Single Plate Clutch

A single plate clutch assembly for transmission of power consists of a flywheel, a clutch plate, pressure plates, clutch covers, release levers, primary or clutch shaft.

  1. Flywheel
  2. Pilot Bearing
  3. Clutch plate or Disc plate
  4. Pressure plate
  5. Clutch cover
  6. Release levers
  7. Clutch shaft

1) Flywheel

The flywheel is an integral part of the engine, which also use as a part of the clutch. It is a driving member and connects to the pressure plate of the clutch shaft is houses with bearings in a flywheel. The flywheel rotates as the engine crankshaft rotates.

2) Pilot Bearing

The pilot bearing or bushing press into the end of the crankshaft to support the end of the transmission input shaft. The pilot bearing prevents the transmission shaft and clutch disc from wobbling up and down when the clutch releases. It also assists the input shaft center of the disc on the flywheel.

3) Clutch plate or Disc plate

It is the driven member of the single-plate clutches and line with friction material on both surfaces. It has a central hub with internal splines to limit the axial travel along the splined gearbox driving shaft.

This helps to provide damping actions against torsional vibrations or variations of the driving torque between engine and transmission.

A clutch disc is a plate between flywheel and friction or pressure plate. It has a series of facings inverters on each side to enlarge the friction. These clutch facings are made of asbestos material. They are highly worn and heat resistant.

4) Pressure plate

The pressure plate is made of special cast iron. It is the heaviest part of the clutch assembly. The main function of the pressure plate is to establish even contact with the driven plate facing through which the pressure springs can exert a sufficient force to transmit the full torque of the engine.

The pressure plate presses the clutch plate on to the flywheel from its machined surface. Between the pressure plate and clutch cover assembly, pressure springs are fitted.

The pressure will be withdrawn from the flywheel whenever release levers are depressed by the toggle or release levers are pivoted accordingly.

5) Clutch cover

The clutch cover assembly bolts to the flywheel. It consists of a pressure plate, release lever mechanism, clutch cover, and pressure springs. Generally, the clutch plate revolves with the flywheel.

However, when the clutch has disengaged, the flywheel, as well as the pressure plates, are free to rotate independently from the driven plate and driving shaft.

6) Release levers

These pivots on pins to the clutch cover, their outer ends locate and positions on pressure plate legs, and the inner ends are projecting towards the clutch shaft.

A careful and accurate adjustment of the release mechanism is one of the most important factors governing the performance of a clutch assembly.

7) Clutch shaft

It is a component of the gearbox. Since it is a splined shaft to the hub of the clutch plate, which is sliding on it. One end of the clutch shaft attaches to the crankshaft or flywheel and the other end connects to the gearbox or forms a part of the gearbox.

Types of Single Plate Clutch

  • Helical Spring Single Plate Clutches
  • Diaphragm Spring Single Plate Clutches

1. Helical Spring Single Plate Clutch

For simplicity’s sake, the clutch pedal and other links causing movement of the pressure plate are not shown.

The clutch plate is mounted on the splined shaft and can move along the axis of the shaft. There is no relative movement between plate and shaft as far as rotational movement is concerned.

Both have the same rotational movement due to splines provided on the shaft. The flywheel is mounted on the engine crankshaft and rotates with it. The pressure plate is bolted to the flywheel through clutch springs. It can slide freely along the axis of the clutch shaft.

The clutch is engaged due to the force exerted by the clutch springs. This force causes contact between the pressure plate, clutch plate, and flywheel. The clutch plate is located between the flywheel and the pressure plate. The clutch plate is provided with friction material on both sides.

The rotary movement from the flywheel is transferred to the clutch plate and the clutch shaft due to friction. The clutch shaft also acts as the output shaft.

When the clutch pedal is pressed the clutch is ‘disengaged.’ The pressure plate moves back against the force of springs, and the clutch plate becomes free between the flywheel and the pressure plate.

Thus, the flywheel continues to rotate as long as the engine runs but the speed of the clutch plate declines and becomes zero. In this situation, motion is not transferred to the clutch shaft.

2. Diaphragm Spring Single Plate Clutch

In this type of clutch, the helical springs are replaced by a single diaphragm spring which is a saucer-shaped disc. The disc adopts a flat shape when the clutch is engaged. In the disengaged position, the disc adopts a buckled shape as shown.

The view shows the clutch in the ‘engaged’ position. The diaphragm spring exerts the force on the pressure plate, which causes the contact between the pressure plate, clutch plate, and flywheel.

When force is applied through the clutch pedal, the diaphragm spring is buckled and contact between the pressure plate, clutch plate, and the flywheel is lost. The clutch is disengaged,’ and motion from the flywheel is not transferred to the clutch shaft.

Application of Single Plate Clutch

Single plate clutch applications are as follows :

  • Single plate clutches are used in Buses, Trucks, and cars, etc.
  • Single plate clutches are used where large radial space is available.
  • This type of clutch does not require any lubricant for cooling.
  • As sufficient surface area is available for the heat dissipation in Single plate clutches, no cooling oil is required. Therefore, single plate clutches are dry type.
  • Due to the high coefficient of friction, most of the vehicles use a single plate clutch. The amount of the coefficient of friction is more than 0.3.

Advantages Of Single Plate Clutch

The main advantages of this clutch include:

  • Single plate clutch is smooth in operation i.e engagement and disengagement of clutch is smooth.
  • Very little slip occurs in its operation. Slip only occurs during the engagement of the clutch and after that, no slipping occurs and functioning becomes very smooth.
  • Power loss is very less.
  • Very little heat is generated as only one clutch plate is used.
  • The operation in this type of clutch is very fast.

Disadvantages of Single Plate Clutch

The main disadvantages of this clutch include:

  • Single plate clutches have high wear and tear rate.
  • It has less torque transmitting capacity.
  • The springs have to be stiffer hence greater force requires to disengage.
  • It requires high maintenance.
  • The space required to accommodate the clutch is more as compared to the multi-plate clutch.

FAQs.

What Is Single Plate Clutch?

A single plate clutch has one clutch plate. This clutch works on the principle of friction. It is the most common type of clutch used in motor vehicles. The clutch primarily consists of two members, one mounted on the driving shaft and the other on the driven shaft.

What are the parts of a single plate clutch?

Parts of Single Plate Clutch:

  1. Flywheel
  2. Pilot Bearing
  3. Clutch plate or Disc plate
  4. Pressure plate
  5. Clutch cover
  6. Release levers
  7. Clutch shaft

What are the types of Single plate clutch?

A single plate clutch has one clutch plate and works on the principle of friction. These are of two types: the Helical spring type and the Diaphragm spring type. In helical spring-type clutches, the helical springs are used uniformly over the cross-sectional area of the pressure plate to exert axial force.

Where is a single plate clutch used?

In the single-plate clutch, a friction plate (clutch plate) is held in between the flywheel and the pressure plate. The Single plate clutch is used to transmit a small amount of power compared to the multi-plate clutch. The single-plate clutch is used in trucks, cars, buses, etc.

What are the advantages of a single plate clutch?

Advantages of Single Plate Clutch: Because of its quick response to the operation of the single-plate clutch, users should use the single-plate clutch. The heat can be generated by the clutch due to the frictional force that damages the other parts which helps in the process of power transmission.

What is the difference between single plate clutch and multi plate clutch?

Difference between Single Plate Clutch and Multi Plate Clutch. As the name suggests, a single-plate clutch consists of a clutch plate whose both sides are coated with a frictional material. The multi-Plate clutch consists of more than one clutch plate. Torque transmitting capacity is less.

What is the advantage of multi plate clutch over single plate clutch?

The number of friction surfaces increases the capacity of the clutch to transmit torque, though the size remains fixed. Therefore, considering the same torque transmission, the overall diameter of the multi-plate clutch is reduced when compared to a single plate clutch.

What are the types of single plate clutch?

The single-plate clutch consists of a clutch plate and operates on the principle of friction. These are of two types: helical spring type and diaphragm spring type. In helical spring-type clutches, helical springs are used uniformly over the cross-sectional area of ​​the pressure plate to suppress the axial force.

How many friction surfaces are available in single plate clutch?

Thus, the single-plate clutch has two pairs of friction surfaces. The analysis of the turning torque is done in the following two conditions i. Uniform pressure ii. Uniform wear the condition of the uniform pressure is used only for the new clutches.

Why single plate clutch is better than cone clutch?

The cone clutch transfers a higher torque than plate or disk clutches of the same size due to the wedging action and increased surface area. This is because the clutch does not have to be pushed in all the way and the gears will be changed quickly.

How single plate clutch is better than cone clutch?

In a Cone Clutch fewer chances of slip between the mating surfaces. So, almost 100% transfer of torque is guaranteed. In Single Plate Clutch Due to slip between mating surfaces, less torque is transmitted compared to cone clutch.

Why single plate clutch is called dry clutch?

As the name suggests this clutch consists of only one clutch plate with both side friction lining (frictional surface). These surfaces have a high Coefficient of friction. A single plate clutch is also called a dry clutch because no lubricant is used as a coolant.

Why single plate clutch is used in trucks?

While in an engine of a car, the size of the engine is large, and as is the space available. So for maximum power transmission, a bigger clutch plate can be easily used. Therefore, in cars, multi-plate clutches are not so common. A single plate clutch serves the purpose efficiently with optimum power transmission.

Why single plate clutches are dry?

The working of engagement and disengagement is very smooth in a single plate clutch. Power losses are very less. As sufficient surface area is available for heat dissipation in such clutches, no cooling oil is required. Therefore, single plate clutches are dry type.

What is single clutch transmission?

One clutch controls the odd gears (first, third, fifth, and reverse), while the other controls the even gears (second, fourth and sixth). Using this arrangement, gears can be changed without interrupting the power flow from the engine to the transmission.

What is function of clutch plate?

Most automotive clutches are dry single-plate clutches with two friction surfaces. No matter the application, the function and purpose of a clutch are to transmit torque from a rotating driving motor to the transmission. The pedal translates a parabolic swing of the clutch pedal into a linear movement.

What is the function of clutch spring shown in the single plate clutch?

Function: When your foot is off the pedal, the springs push the pressure plate against the clutch disc, which in turn presses against the flywheel. This locks the engine to the transmission input shaft, causing them to spin at the same speed.

When compared with single plate clutch the coefficient of friction?

A plate clutch consists of 1 pair of contacting surfaces. The inner and outer diameter of the friction disk is 100mm and 200mm respectively. The coefficient of friction is 0.2 and the permissible intensity of pressure is 1.5N/mm².

When applying a single clutch plate which oil is filled into the clutch plate?

As sufficient surface area is available for the heat dissipation in Single plate clutches, no cooling oil is required. Therefore, single plate clutches are dry type. Due to the high coefficient of friction, most of the vehicles use a single plate clutch. The amount of the coefficient of friction is more than 0.3.

What are the types of single plate clutch?

The single-plate clutch consists of a clutch plate and operates on the principle of friction. These are of two types: helical spring type and diaphragm spring type. In helical spring-type clutches, helical springs are used uniformly over the cross-sectional area of ​​the pressure plate to suppress the axial force.