The Concentric Slave Cylinder (CSC) is an important component of an automotive clutch system that is typically used to control the engagement and disengagement of the clutch for shifting and stopping. It is also known as a concentric sleeve slave. The main function of the concentric slave cylinder is to transfer the hydraulic pressure generated by the master cylinder to the clutch pressure plate, thus disengaging the clutch or connecting the engine power.

The concentric slave cylinder works in close co-operation with the throwout bearing (Separator Bearing) or the release bearing (Slave Bearing) to perform this function. The following is a detailed description of the concentric slave cylinder:

1. Structure: Concentric Slave Cylinders have a coaxial design and contain two internal parts: a hydraulic piston that is connected to the clutch master cylinder, and a push section that is connected to the clutch operating rod. These two parts together form a concentric structure, hence the name concentric slave cylinder. Its function is to control the position of the throwout bearing by means of hydraulic or pneumatic force, which in turn controls the engagement and disengagement of the clutch.

2. Principle of operation Concentric Slave Cylinder: When the driver depresses the clutch pedal, the gearbox control system reduces the pressure in the concentric slave cylinder so that the throw-out bearing is released and no longer locks up with the Torque Converter or the guide wheel of the clutch. In this way, engine power can be transferred to the transmission through the torque converter or clutch.

3. Engagement Process: When the clutch pedal is released, the control system increases the pressure on the concentric slave cylinders, causing the throwout bearing to relock with the guide wheel, thus disconnecting the engine power for shifting or stopping.

4. Control Valve: The operation of the concentric slave cylinders is controlled by a control valve in the gearbox. The control valve regulates the pressure in the concentric slave cylinders for engagement and disengagement according to the driver's actions and the vehicle's operating conditions.

5. Advantages: The design of the concentric slave cylinders results in a smoother shifting process, reducing shocks and delays during gear changes. It also simplifies the shift operation and provides a convenient stopping function.

6. Precision and Reliability: Concentric slave cylinders have a smaller installation space compared to conventional clutch followers (i.e., breakaway followers), reducing the number of components and complexity, while improving the precision and reliability of clutch operation.

7. Transmission Efficiency: The design of the concentric slave cylinder allows it to be concentric with the input and output shafts of the transmission, which means that their centre axes are the same. This design helps to reduce energy loss during transmission and improves overall transmission efficiency.

8. Maintenance: Maintenance of the concentric slave cylinders consists mainly of regular inspection and replacement of the hydraulic or pneumatic oil. If the concentric slave cylinders are found to have problems such as wear, oil leakage or strange noise, they should be inspected and repaired as soon as possible.

In short, Concentric Slave Cylinder (CSC) usually refers to a so-called clutch/brake set in the automotive driveline, where the Concentric Slave Cylinder is usually combined with a clutch or brake in an automatic transmission. It is the slave part of the transmission and is used to transfer power from the input shaft of the transmission to the output shaft. In close co-operation with the throw-out bearing, it ensures smooth and efficient power transmission between the engine and the gearbox. When a gear change is required, the control unit instructs the hydraulic system to apply pressure to the appropriate clutch or brake to engage or disengage it, thus permitting power to be transmitted or interrupted to the output shaft.