What is Clutch?
How does it work?

Clutch is a kind of clutch connected between the engine and the transmission (gearbox). A clutch is used to transfer the movement of any shaft to a different shaft in the same direction. However, this equipment cannot separate or connect the shafts while they are rotating. However, this is required for motor vehicles. Because the first start of the engine must be done without load (putting the gear to neutral and starting it). After the engine reaches a certain speed, it is necessary to load the engine. This process is done with the clutch.

Another important issue in power transmission systems is the transmission of the desired speed to the wheels. Normally, an engine at idle has a speed of around 750 rpm. Transmitting this speed directly to the wheels means that the vehicle accelerates suddenly and loses control. If the wheels are connected to the engine with a gear system, the desired wheel speed is achieved.

Part of the speed reduction is done by the differential. In the differential, the reduction is fixed. However, the gearbox system is different. Depending on the conditions, high torque, low speed or high speed, low torque can be provided. For this purpose, the gear group cycle ratios must be adjusted as necessary. A clutch is needed for this process.

When you want to stop a vehicle, it is necessary to disconnect the engine and drivetrain from each other. To do this, the clutch is pressed before the vehicle stops, the transmission and the engine are separated from each other and the gear is put into neutral. After this, the vehicle can be stopped using the brakes. Basically, the clutch is a power transmission system that takes the movement of the engine's crankshaft from the flywheel using a pad and pressure plate and transmits it to the transmission.

Clutch Working Principle

Clutches work by utilizing friction force. In the clutch section shown in the figure below (right click to enlarge and open in a new tab), flywheel A is connected to the crankshaft of the engine. A C disc is inserted into the B shaft, which goes to the gearbox, with a key. Two plates with high friction coefficient, called linings, are riveted to both surfaces of this disc in the form of a friction circle. This is called clutch disc or lining disc.

The other end of the coil springs fixed at E, which is the clutch cover, rests on the pressure plate, that is, D. With the pressure created by these springs, the pressure plate compresses the pad disc between itself and the flywheel surface. Thus, during rotation, the brake disc, pressure plate and clutch cover rotate together with the flywheel due to the pressure effect occurring between both surfaces of the brake disc and the pressure plate and flywheel surfaces. Since the lining disc is fixed to the B shaft, the movement of the engine is transferred to the transmission.

It is sufficient to depress the clutch pedal to separate the engine and transmission. Thus, as the spring pressure holding the flywheel, pad disc and pressure plate together through the lever arms connected to the pedal will be eliminated, the pressure plate moves away from the pad disc. In this case, the flywheel and pressure plate are disconnected from the lining disc and the B shaft connected to it and they can rotate. In high-torque gears (such as 1st gear), if the engine speed increases rapidly but there is no increase in the speed of the car, or if the clutch cannot keep up with the engine when the accelerator pedal is suddenly pressed and released, that is, if the speed does not meet the speed, there may be a problem with your brake lining.