Types of clutch

Different Types Of Clutch And How They Work

Due to the fact that a clutch is one of the most important components in a car, it is made of different types to meet different requirements. In the previous lesson, the clutch was explained to be a mechanical device that engages and disengages the power transmission from the driving shaft to the driven shaft. We also revealed that it features two shafts; one is connected to the engine or power unit (the driving member), while the other shaft provides the power output that does the work.

Contents

Recap

A clutch is used to separate the engine’s power from the transmission and engage it whenever needed. Pressing down the clutch pedal disengages the connection, and releasing it allows the power to flow to the transmission and the wheels.

The different types of clutches include friction clutches, centrifugal clutches, hydraulic clutches, semi-centrifugal clutches, and cone clutches. Clutches employ the principles of friction, particularly between the clutch plate and flywheel, for their operation.

Types of clutch

Let’s get into more detail!

Various Types Of Clutch

Friction Clutch:

In this clutch, surfaces attached to the driven and driving shafts create friction that transfers the drive. These surfaces are lined with cork, asbestos, or other fibrous material. Cars with friction clutches need to have the linings replaced periodically. The friction clutch is of two different types: a single-plate clutch and a multiple-plate clutch.

Single clutch plate: the single clutch is the most common and used clutch found on modern light vehicles. It helps transmit torque and power from the engine to the transmission input shaft. It is just on the plate, as the name indicates.

Multiple clutch plate: just as the name states, a multiple clutch plate uses multiple clutches to make frictional contact with the engine’s flywheel. This transmits power between the engine shaft and the transmission shaft of the vehicle. The number of friction surfaces determines the capacity of the clutch to transmit torque.

Hydraulic Clutch:

In the working principle of a hydraulic clutch, the oil reservoir pumps oil into the accumulator with the aid of a pump. This pump works together with the engine, and the accumulator is connected to the cylinder through the control valve.

The control valve is operated by the switch mounted on the gear lever. The piston is connected to the clutch by the linkage mechanism. The switch opens the control valve when the driver holds the gear lever to change the gears, which allows the oil under pressure to enter the cylinder.

The oil pressure moves the piston forward and backward, which causes the clutch to get disengaged. If the driver releases the gear lever, the switch is open, which closes the control valve, and the clutch will be engaged.

Centrifugal Clutch:

Centrifugal types of clutches use a centrifugal force to engage the clutch, unlike others that work with spring force. The benefit of this clutch is that the driver can easily stop the vehicle in any gear without stalling the engine. The vehicle can be easily started in any gear by pressing the accelerator pedal.

The working of a centrifugal clutch is quite different as it consists of weights A pivoted at B. The weights fly off due to the centrifugal force when the engine speed increases. The centrifugal force applied operates the bell crank levels, which press plate C.

The movement of plate C presses the spring E, which extremely presses the clutch plate D on the flywheel against the spring G. This engages the clutch. The spring G helps to disengage the clutch at low speeds at about 500 rpm, and the stop H limits the movement of the weights.

Semi-centrifugal Clutch:

The semi-centrifugal clutch also uses centrifugal force along with a spring force, which helps it in the engaged position.  The clutch consists of levers, clutch springs, pressure plate, friction lining, flywheel and clutch plate.

The working of a semi-centrifugal clutch also occurs at normal engine speeds; when the power transmission is low, the springs keep the clutch engaged. The weighted levers do not put any pressure on the pressure plate.

And at high engine speeds, when the power transmission is high, the weights fly, which allows the levers to exert pressure on the plate. This keeps the clutch firmly engaged. The springs in these types of clutches consist of less stiff springs, which allows the driver not to experience any strain while operating the clutch.

Cone Clutch:

In a cone clutch, the friction surfaces are in conical shape with two surfaces to transmit torque. The engine shaft consists of a female cone and a male cone. The male cone is mounted on the splined clutch shaft, which slides on it. This conical portion has a friction surface.

The friction surfaces of the male cone come in contact with the female cone due to the force of spring when the clutch is engaged. However, when the clutch pedal is pressed, the male cone slides towards the spring force, which disengages the clutch.

One of the great benefits of a cone clutch is that the normal force acting on the friction surface is greater than the axial force. Some limitations also occur in the cone clutch, such as the male cone tending to bind with the female cone, making it difficult to disengage.

Diaphragm Clutch:

The diaphragm clutch contains a diaphragm on a conical spring, which produces pressure on the pressure plate for engaging the clutch. The spring used is either a crown or finger type, which is attached to the pressure plate. In this type of clutch, the engine power is transmitted from the crankshaft to the flywheel, which contains a friction lining. The pressure plate is located behind the clutch plate because it applies pressure to it.

In diaphragm clutch working, the diaphragm is a conical shape of the spring that allows the outside bearing to move towards the flywheel when pressed. The flywheel pressing the diaphragm spring pushes the pressure plate backward. This allows the pressure on a plate to be restricted, and the clutch will be disengaged. If the clutch pedal is released, the pressure plate and diaphragm spring will come back to their normal positions, and the clutch will get engaged.

The advantage of the clutch is that there are no release levers because the spring takes the position. Drivers do not need to apply such heavy pedal pressure to hold the clutch disengaged. This is because the coil spring pressure increases more when the pedal is depressed to disengage the clutch.

Electromagnetic Clutch:

The electromagnetic type of clutch is operated electrically, but the clutch is transmitted mechanically. This clutch has no mechanical linkage to control its engagement, which is why fast and smooth operation occurs. It uses a remote for its operation, allowing the clutch to be operated from a distance.

The electrical power is supplied by the battery, and the clutch flywheel contains a winding. The winding allows electricity to pass through it, produces an electromagnetic field, and makes the pressure plate get engaged. It disengages when its power supply is cut off.

In an electromagnetic clutch, there is a clutch release switch in the gear level, which allows the driver to operate the gear lever when changing gears. This switch is operated by cutting off the current supply to the winding, which causes the disengagement.

Types of clutch

Dog and Spline Clutch:

The dog and spline types of clutches are used to connect the gear and shaft, or lock and shaft, together. The major parts of the clutch are the dog clutch, which contains the external teeth, and the sliding sleeve, which has the internal teeth.

The shafts are designed to rotate one another at the same speed and will never slip. The clutch is said to be engaged when the two shafts are connected. The clutch is disengaged when the sliding sleeve moves back on the splined shaft to have no contact with the driving shaft. These types of clutches are mostly used in manual transmission vehicles, which help lock different gears.

Vacuum Clutch:

This clutch uses the existing vacuum in the engine manifold to work. The vacuum clutch consists of a reservoir, non-return valve, vacuum cylinder with piston, and solenoid valve. The reservoir is connected to the inlet manifold through a non-return valve. A vacuum cylinder is connected to a reservoir through a solenoid-operated valve.

This solenoid receives power from the battery for its work, and the circuit has a switch that is attached to the gear lever. The switch is operated when the driver changes the gear by holding the gear lever. The solenoid energizes and pulls the valve up, which connects one side of the vacuum cylinder to the reservoir. This mechanism opens the passage between the vacuum and the reservoir.

Different levels of pressure allow the vacuum cylinder piston to move forward and backward. The movement of the piston is transferred to the clutch by a linkage, causing it to disengage. If the gear lever is not operated, the switch is open, and the clutch remains engaged because of the force of the springs.

Freewheel Unit:

The freewheel unit clutch is also known as spring clutch, one-way clutch or overrunning clutch. Its transmission power is in one direction, just as in bicycle transmission. The freewheel is located behind the gearbox. The main shaft transmits the power from the main shaft to the output shaft, which drives the output shaft when the planetary gears are in overdrive.

There is a hub and an outer race contained on the flywheel unit. This hub has internal splines to connect it to the transmission main shaft. The outer surface of the hub has 12 cams designed to hold 12 rollers in a cage between them and the outer race. The outer race is splined to the overdrive outer shaft.

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Comments

9 responses to “Different Types Of Clutch And How They Work”

  1. JeffreyReend Avatar
    JeffreyReend

    I’m grateful to have found this post after searching through several other blogs for information about different types of clutches. This content is truly informative and valuable.

  2. For those who aren’t aware, in most manual transmission vehicles it is possible to shift gears without use of the clutch. This is done by matching the engine output RPM with the rotational speed of the vehicle’s transmission output. And this article comprehensively covers the different type of clutches. A very big thanks to the author.

  3. Winters Ronald Avatar
    Winters Ronald

    This article is so on point. Many thanks to the writer. I would love to indicate that, at its core, a car clutch is essentially a mechanical device that connects and disconnects the engine’s power from the transmission, allowing you to change gears smoothly. It’s an essential component of manual transmissions, serving as the intermediary between the engine and the wheels.

  4. Great post! I appreciate it.

  5. Donovan Henderson Avatar
    Donovan Henderson

    Most cars use a friction clutch, which contains the typical components you may have seen or heard of before. Operated hydraulically or by a cable, a friction clutch uses a pressure plate, a clutch plate (or clutch disk), and a release bearing to engage and disengage the flywheel and the transmission. This was a very informative article. Keep up the good work!

  6. A better way to view the friction clutch is: When the clutch pedal is pressed, the release bearing moves forward, which disengages the clutch plates. This causes the clutch disc to separate from the flywheel and the pressure plate, interrupting the flow of power between the engine and the transmission.

  7. Robert Unfon Avatar
    Robert Unfon

    Great job man. This was very infromative!

  8. Thank you for this wonderful piece of writing. I found value in the article. The function of a clutch is to engage and disengage the power between the engine and gearbox. A clutch thus provides an interruptible connection between two rotating shafts. Clutches allow a high inertia load to be stated with small power.

  9. Tlover Tonet Avatar
    Tlover Tonet

    Now i get it! A clutch is used to connect two moving shafts that are operating at different speeds. It allows for the disengagement of engine power and facilitates smooth vehicle operation. When the clutch pedal is pressed, the movable friction disc slides on the shaft, causing disengagement. Thank you very much for such great information!

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