Structure of clutch

The clutch is installed between the engine and the transmission. The clutch is often used in the whole process from starting to driving. Its function is to gradually connect the engine and transmission, so as to ensure the smooth start of the car; Temporarily cut off the connection between the engine and the transmission to facilitate gear shifting and reduce the impact during gear shifting; When the vehicle is under emergency braking, it can play a separation role, prevent the transmission system such as transmission from overload and play a certain protective role. The clutch is similar to a switch, which engages or disconnects the power transmission function. Therefore, any form of automobile has a clutch device, but the form is different. The hydraulic torque converter of automatic transmission has the function of clutch, while the clutch of manual transmission mainly adopts the form of friction, and becomes an independent device with its own control system. Therefore, ordinary manual transmission vehicles have a clutch pedal device, which is installed at the front left end of the driver’s seat. This paper mainly expounds the friction plate clutch and its control form on the car with manual transmission.


The car adopts diaphragm clutch, which is composed of active part (a whole composed of shell, diaphragm spring and pressure plate and fixed on the engine flywheel with screws), passive part (composed of friction plate and driven plate) and control part. The passive part is installed between the flywheel and the pressure plate and sleeved on the input shaft of the transmission through sliding splines. Under the elastic force of the diaphragm spring (4), the driven plate (1), the pressure plate (3) and the flywheel (2) are clamped. When the engine is working, the flywheel and the pressure plate drive the driven plate to rotate together through the friction between them and the friction plate, and transmit the torque to the driving shaft of the transmission. When the driver depresses the clutch pedal, the release fork of the control part pushes the release bearing forward and pushes the lower end of the diaphragm spring to make the upper end of the diaphragm spring rotate around the fulcrum and pull the pressure plate to move backward, which relieves the pressing force between the pressure plate and the friction plate. The engine can only drive the active part to rotate and cannot transmit torque to the transmission. When the driver releases the clutch pedal, the control part pulls the release bearing back, the pressure at the lower end of the diaphragm spring is relieved and restored to the original position, the pressure plate moves forward again under the pressure of the diaphragm spring and compresses the friction plate, and the engine can transmit the torque to the transmission. Several transverse spiral springs are evenly distributed on the friction plate to reduce the impact and vibration during clutch.

At present, there are two types of automobile clutch control: pull wire and hydraulic control. Most cars use hydraulic control. It has the advantages of low noise, labor-saving, stable and convenient layout. It is composed of master cylinder, slave cylinder, hose and pedal. When the driver depresses the clutch pedal, the push rod pushes the master cylinder piston to increase the oil pressure and enters the slave cylinder through the hose, forcing the slave cylinder pull rod to push the release fork and push the release bearing forward; When the driver releases the clutch pedal, the hydraulic pressure is released, the release fork gradually returns to the original position under the action of the return spring, and the clutch is engaged again.

Now, electronic technology has also entered the clutch system. A clutch controlled by a control unit (ECU) has been applied to a variety of coupes. Its ECU collects signals such as accelerator pedal, engine speed sensor and vehicle speed sensor to drive the servo motor mechanism to implement automatic transmission.

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