What is clutch? 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 (gear box).
However, besides to connect and disconnect the engine power to the transmission, there are several clutch functions :
· Makes the gearshift more easier
· Stopping the car without changing the gear to neutral position while the engine still run.
· Makes the car to move smoothly on the first movement.
· Freeing the car movement without engine brake
In the automobile, there are various type of clutches, and its depend upon the type and use of vehicles such as dry clutch, wet clutch, single clutch, double clutch, and so on. But the most often used in an automobile with manual transmission is a single plate dry clutches.
In this post, we will give you an information about main components of car clutch and its function. Here are the car clutch components and function...
1. Flywheel
The first car clutch component is flywheel. 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.
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 3 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 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 transmission.
This bearing sits either in the center 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 clutch (friction) disc. The clutch disc is the connecting link between the engine and the transmission. It's a component that used to connect or disconnect the engine rotation to input shaft the transmission.
A clutch disc always connected to the input shaft of transmission and it's sandwiched in between the flywheel and pressure plate. It is provides a large surface area made of friction material on both sides so when it pressed by flywheel and pressure plate, the clutch disc will transmit the engine rotation to the transmission.
To ensure the flowing energy from engine to the transmission is transmitted well and comfortable, the clutch disc is made by several components such as :
· Clutch hub, clutch hub is a hub were connecting the input shaft and clutch disc. So, when the clutch disc is rotate, it's rotate the input shaft too.
· Clutch facing, clutch facing is friction materials were riveted to the cushion plate on both -side and has direct contact with flywheel and pressure plate surfaces.
· Torsion dampers, torsion dampers absorb the shock of: clutch engagement, acceleration, deceleration, and power pulses from the engine.
· Cushion plate, cushion plate has a wave design that allows the facings to compress when the pressure plate is engaged. This provides a smooth engagement of engine and transmission.
4. Clutch cover assembly
The fourth car clutch component is clutch cover assembly. The clutch cover is bolted to the flywheel and provides the pressure needed to hold the clutch disc to the flywheel for proper power transmission.
The clutch cover assembly function is to engage and disengage power from engine to the transmission via clutch disc. If the clutch disc is always connected to the transmission via input shaft, the clutch cover assembly is always connected to the engine via flywheel.
There are three main components of clutch cover assembly that serves ability to connect or disconnect the power from engine to transmission.
· Pressure plate, pressure plate works together with flywheel surface to clamp and pressing the clutch disc so the power will flowing to the input shaft.
· Diaphragm spring, diaphragm spring is used to press the pressure plate so the plate has power to hold the clutch disc.When the diaphragm spring pressed by release bearing, the pressure plate will loose its pressure and the clutch will disengage the power.
· Cover, cover is used as a body of clutch cover assembly and its bolted to the flywheel so the clutch cover assembly rotation is the same as the engine rotation.
5. Clutch release bearing
The fifth car clutch component is 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 clutch cover to disengage the clutch disc.
The clutch release bearing is attached on clutch release fork. When the clutch release fork is moving close to the diaphragm spring, the clutch release bearing will comes in contact with the rotating diaphragm spring, and the outer race of the bearing will begin to rotate.
At the same time, the realese bearing will press the diaphragm spring and lift off the pressure plate. As the pressure plate is lifted off, the clutch disc disengage the power.
6. Clutch release fork
The last car clutch component is 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, clutch release fork is connected to to the clutch slave cylinder.
The clutch slave cylinder operates the fork movement and the release fork pivots on a ball stud inside the transmission bell housing. So, when the clutch slave cylinder rod pushed the fork, the fork will pushed the release bearing and make the pressure plate lift off from the clutch disc.