Car clutch components and function

What is clutch? A Clutch is a mechanism to connect and disconnect the engine power to the driving wheels as per the road and load conditions. In an automobile, the clutch is located between the engine and transmission (gearbox). So that torque can be transmitted from engine to the transmission whenever required.

However, besides to connect and disconnect the engine power to the transmission, there are several function of clutch, such as :

It makes the gearshift easier
Stops the car without changing the gear to a neutral position while the engine still runs.
It makes the car move smoothly on the first movement.
Freeing the car movement without engine brake

In the clutch automobile, there are various types of clutches. It depends upon the type and use of vehicles such as dry clutch, wet clutch, single-clutch, double-clutch, etc. But the most often used in an automobile with manual transmission is a single plate dry clutches.

This post will give you information about the main clutch components of a car and its function. Here are the car clutch components and functions.

1. Flywheel

The first car clutch component is the Flywheel. A clutch flywheel connected to the rear engine crankshaft and will rotates at the same speed with engine rotation. A flywheel is very similar to a brake rotor in appearance. It is a large metal disc that stores and releases energy pulses from the crankshaft.

The Flywheel also drives the clutch by providing a friction surface for the clutch disc. In addition, the Flywheel provides a mounting surface for the clutch cover and also dissipates heat.

The Flywheel has three major functions such as :

To provide one of the driving friction surfaces for the clutch (friction) disc.
To maintain a rotating mass (inertia) to assist the engine rotation during running.
To provide a ring gear for the starter motor to engage on.

2. Pilot Bearing

The second car clutch component is the pilot bearing. A Pilot Bearing is not present in all clutch assemblies but is most common in Rear Wheel Drive engine configurations. A pilot bearing supports the engine side of the input shaft from the transmission.

This bearing sits in the centre back of the crankshaft or in the flywheel and locates the input shaft. The pilot bearing used a ball bearing which only turns when the clutch is disengaged.

It is important to locate the input shaft in the back of the crankshaft for correct clutch life and operation. Without a pilot bearing, excessive wear can occur in the splines and the hub of the clutch disc, which can cause clutch release issues.

3. Clutch (friction) disc

The third car clutch component is the clutch (friction) disc. The clutch disc is the connecting link between the engine and the transmission. It's a component used to connect or disconnect the engine rotation to input shaft the transmission.

A clutch disc is always connected to the transmission's input shaft, and it's sandwiched in between the flywheel and pressure plate. It provides a large surface area made of friction material on both sides. The clutch disc will transmit the engine rotation to the transmission when pressed by flywheel and pressure plate.

To ensure the flowing energy from the engine to the transmission is transmitted well and comfortable, the clutch disc is made by several components such as :

Clutch hub, the clutch hub is a hub were connecting the input shaft and clutch disc. So, when the clutch disc is rotating, it rotates the input shaft too.
Clutch facing is friction materials riveted to the cushion plate on both sides and directly contact flywheel and pressure plate surfaces.
Torsion dampers, torsion dampers absorb the shock of clutch engagement, acceleration, deceleration, and power pulses from the engine.
The cushion plate. The cushion plate has a wave design that compresses the facings when the pressure plate is engaged. It provides a smooth engagement of engine and transmission.

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4. Clutch cover assembly

The fourth car clutch component is clutch cover assembly. The clutch cover is bolted to the flywheel. It provides the pressure needed to hold the clutch disc to the flywheel for proper power transmission.

The clutch cover assembly function engages and disengages power from the engine to the transmission via clutch disc. If the clutch disc is always connected to the transmission via the input shaft, then the clutch cover assembly is always connected to the engine via flywheel.

There are three main components of clutch cover assembly that serves the ability to connect or disconnect the power from the engine to transmission.

Pressure plate. The pressure plate works with the flywheel surface to clamp and press the clutch disc to flow to the input shaft.
Diaphragm spring, diaphragm spring is used to press the pressure plate, so the plate has the power to hold the clutch disc. When the diaphragm spring is pressed by release bearing, the pressure plate will lose its pressure and the clutch will disengage the power.
Cover. The cover is used as a body of clutch cover assembly and bolted to the flywheel. Hence, the clutch cover assembly rotation is the same as the engine rotation.

5. Clutch release bearing

The fifth car clutch component is the clutch release bearing. The purpose of the clutch release bearing is to transfer the movement of the clutch release fork into the rotating diaphragm spring on the clutch cover to disengage the clutch disc.

The clutch release bearing is attached to the clutch release fork. When the clutch release fork moves close to the diaphragm spring, the clutch release bearing will contact the rotating diaphragm spring. It makes the outer race of the bearing will begin to rotate.

At the same time, the release bearing will press the diaphragm spring and lift off the pressure plate. As the pressure plate is lifted off, the clutch disc disengages the power.

6. Clutch release fork

The last car clutch component is the clutch release fork. The clutch release fork is used to move the clutch release bearing (attached at the end of the fork) in or out from the diaphragm spring. While on the other side, the clutch release fork is connected to the clutch slave cylinder.

The release fork pivots on a ball stud inside the transmission bell housing. The clutch slave cylinder operates the fork movement. So, when the clutch slave cylinder rod pushes the fork, the fork pushes the release bearing and makes the pressure plate lift off the clutch disc.