What is a Single Plate Clutch and its Working?

Among various components in a vehicle, a clutch is an essential one. It helps to transmit the torque from a rotating driving motor into a transmission. A single plate clutch is the most common clutch type, with only one clutch plate. 

It is important to understand the role of a clutch to choose the right one. 

Keep reading this article for all about a single plate clutch. 

As its name suggests, there is only a single plate in a single plate clutch, which is attached to the shaft’s spline. It comes with a friction principle. It has two parts, one fixed on the driven shaft and another one on the driving shaft. The flywheel of an engine is attached to its crankshaft, and they revolve together. 

A pressure plate gets fastened to a flywheel when the clutch pedal is depressed and glides on the clutch shaft. This clutch plate comes between the flywheel and the pressure plate and a friction between these two parts and the clutch plate causes its clutch shaft to rotate with such a plate.

The construction of a single plate clutch is complicated, as it aims at the ultimate effectiveness of this type of clutch in a vehicle. Primarily, it comprises a single clutch plate with friction linings on both sides. Apart from that, there are other parts like flywheels, hubs, springs, thrust bearings, etc.

A clutch plate is attached to the hub between the flywheel and the pressure plate. Its friction line has the role of torque transmission. On the other hand, the flywheel and springs are engaged with the pressure plate, which pushes a clutch plate along with the flywheel. Input and output motion comes through a lever in a clutch pedal attached to its thrust bearings. 

Multiple parts of a single plate clutch contribute to its development. They have their own functions, which help this type of clutch ensure its effectiveness. Here are the parts that contribute to this type of clutch:

1. Clutch Plate

It is the main component of a single-plate clutch. As discussed, it consists of a single plate. This plate is thin and metallic, with a disc-type appearance, and has friction linings on both sides. This frictional surface offers the necessary torque to transmit in this clutch plate.

2. Engine Shaft

It is a rotating shaft, mainly responsible for converting one form of motion into another.With the clutch parameters, this shaft attaches itself to a vehicle's engine. One of the parameters is a driving shaft attached to this engine. The other one is a driven shaft, which runs via a gearbox in conjunction with its driving shaft.

3. Pressure Plate

Usually made of cast iron, this component is responsible for putting pressure on clutch plates. This process is important to develop better contact between the surfaces of a flywheel and clutch plate with the help of the attached springs.

4. Friction Lining

It represents a friction disc, which assists the clutch in starting and stopping the energy supply between a drive shaft and a driven shaft. With a low coefficient of friction, a friction lining is capable of creating smooth and stable operations.Materials like fibreglass, asbestos, silicon dioxide, etc., create this lining.

5. Clutch Spring

Also known as thrust springs, this component includes helical-coil thrust springs located between the pressure plate and its cover. In compression, this spring offers the necessary torque to load apressure plate against its driven plate. Materials like tensile steel and nickel chrome steel contribute to creating this type of spring.

6. Flywheel

These use a rotating wheel for storing energy, which increases with the moment of inertia as the square of angular velocity. It also acts as a source of energy during the engagement or disengagement of the clutch plates.

7. Clutch Pedal

In the opening parameter of a clutch lies the clutch pedal, whereby a driver operates the clutch. The driver must press the pedal whenever he/she needs to apply the gear. This pedal includes mechanical linkages, which are essential for the engagement and disengagement of this clutch.

8. Release Bearings

Also known as the throw-out bearing, these are located at the back of a pressure plate in the input shaft. The role of these bearings is to reduce the friction between the release fork and lever in a clutch pressure plate. This way, there will be lesser wear on the pressure plate.

Currently, two types of single plate clutches are available in the market. You can choose between them based on your requirements. These two types of clutches are as follows:

Diaphragm Spring Single Plate Clutch

As the name suggests, this type of clutch comes with a single diaphragm spring. It looks like a saucer-shaped disc in a clutch form. This disc changes its shape from buckled to flat when it becomes engaged. The force from the diaphragm spring on the pressure plate connects it with the flywheel and clutch plate.

Helical Spring Single Plate Clutch

Instead of a single diaphragm spring, this type of clutch comes with helical springs. This is a saucer-shaped disc in the form of a clutch. Thisdisc gets flat when its clutch is engaged. Thisclutch plate moves along the shaft's axis on its splined shaft. Anengine’s flywheel revolves around the crankshaft, with clutch springs connecting pressure plates to the flywheel.

One can easily understand the process of working on a single plate clutchdue to its simplistic nature.It mainly occurs across three parts: a clutch plate or friction disc, a flywheel, and a pressure plate.

 Here is a highlight of this process: 

• This process starts with some springs applying the axial force to maintain engagement within a clutch. 

• When an engine starts running, the pressure plate also rotates as it is connected to the flywheel. 

• Once the driving force is pushed, the clutch releases itself. The pressure plate moves away from the friction disc due to this motion. 

• Then, this friction plate is released, causing disengagement of this clutch. 

• As soon as you take your foot off the pedal, the clutch disc presses against itsflywheel, connecting its engine to the input shaft of its transmission. They both spin simultaneously. 

• The piston pulls against the release fork when a clutch is depressed, causing pressure on the throw-out bearing in the diaphragm spring’s centre. 

• With the help of some pins outside a diaphragm spring, the pressure plate draws away from the clutch plate as its spring presses in. 

• Finally, the clutch detaches from its rotating engine. 

Now that you know what a single plate clutch is, it will be easier to learn its advantages. People mostly use this type of clutch for multiple reasons. 

Here are the top advantages of this type of clutch:

• A requirement for maintenance is much limited in this type of clutch. 

• The actions and functions of this clutch are smooth and effortless. 

• This type of clutch is more cost-effective than the others. 

• There is no possibility of slippage in its operation unless the clutch is engaged. 

• There is only one clutch plate, so this type of clutch generates little heat.

• This same reason leads to much lower power loss. 

• It ensures controlledmovement, leading to easier shifting of gears. 

• The overall operations, including the engagement and disengagement of a clutch, are much faster. 

Here are a few factors that can be disadvantageous for users of this type of clutches:

• There is a higher possibility of quicker wear and tear as a single plate functions. 

• More force is required in disengaging as the springs are stiffer. 

• Torque transmission capacity is much limited in this type of clutches. 

• More space is required for accommodating this type of clutches. 

• You need to protect this kind of clutch from moisture, which is an additional duty.

• Additional upkeeping requirements can be downsides for these. 

Hopefully, that gives you a clearer understanding of a single plate clutch. This article finds that this type of clutch is commonly found in most vehicles, and they come with a single clutch plate. However, the construction of this clutch type is complicated, with multiple parts and elements. It is beneficial as it causes low power loss and requires limited maintenance.