What is the definition of pressure bearings

Pressure bearings are separable bearings, which are divided into unidirectional pressure ball bearings and bidirectional pressure ball bearings based on their structural form. 

Unidirectional pressure bearings can withstand axial loads in one direction, while bidirectional pressure bearings can withstand axial loads in two directions. They cannot 

withstand radial loads.

The clutch is installed between the engine and transmission, and is often used throughout the entire process of starting and driving a car. Its function is to gradually engage 

the engine and transmission, ensuring a smooth start of the car; Temporarily cut off the connection between the engine and transmission to facilitate gear shifting and reduce 

the impact during gear shifting; When the car brakes urgently, it can have a separation effect to prevent overloading of transmission systems such as the gearbox, providing a 

certain degree of protection.

The clutch is similar to a switch, which engages or disengages the power transmission function. Therefore, any form of car has a clutch device, but the form is different.The 

hydraulic torque converter of automatic transmissions already has a clutch function, while the clutch of manual transmissions mainly adopts a friction form and becomes a 

device with its own control system. Therefore, ordinary manual transmission cars have a clutch pedal device installed at the left end of the driver's seat in front of the ground. 

This article mainly elaborates on the friction plate clutch and its control form on manual transmission sedans. The sedan adopts a diaphragm clutch, which consists of an active 

part (composed of a shell, diaphragm spring, pressure plate, etc. and fixed to the engine flywheel with screws), a passive part (composed of friction plates and driven plates), 

and a control part.

The passive part is installed between the flywheel and the pressure plate, and is fitted onto the input shaft of the transmission through sliding splines. Under the elastic force of 

the diaphragm spring (4), the driven plate (1), pressure plate (3), and flywheel (2) are clamped. During engine operation, the flywheel and pressure plate drive the driven plate to 

rotate together through their friction with the friction plate, transmitting torque to the transmission drive shaft. When the driver steps on the clutch pedal, the release fork of the 

control part pushes the release bearing forward, pushing the lower end of the diaphragm spring, causing the upper end of the diaphragm spring to rotate around the fulcrum 

and pull the pressure plate to move backward, releasing the pressure 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, and the pressure at the lower end of the 

diaphragm spring is released, returning to its original position. The pressure plate moves forward under the pressure of the diaphragm spring and compresses the friction plate. 

The engine can then transmit torque to the transmission.

Several horizontally placed spiral small springs are also evenly distributed on the friction plate to reduce impact and vibration during clutch operation. At present, there are two 

forms of clutch control for automobiles: cable and hydraulic. Most cars use hydraulic control, which has the advantages of low noise, labor-saving, smooth operation, and 

convenient layout. It is composed of a master cylinder, a slave cylinder, hoses, pedals, etc. When the driver steps on the clutch pedal, the push rod pushes the master cylinder 

piston to increase the oil pressure, which enters the slave cylinder through a hose, forcing the slave cylinder rod to push the release fork and push the release bearing forward; 

When the driver releases the clutch pedal, the hydraulic pressure is released, and the release fork gradually returns to its original position under the action of the return spring, 

and the clutch is in the engaged state again.

Now, electronic technology has also entered the clutch system. A clutch controlled by a control unit (ECU) has been applied in multiple sports cars. Its ECU collects signals from 

the accelerator pedal, engine speed sensor, vehicle speed sensor, etc., and drives the servo motor mechanism to implement automatic transmission.