Slave cylinders (slave or auxiliary cylinders) are called “slave” mainly based on their function and role in hydraulic or pneumatic clutch control systems. The following is an explanation of this designation:

Why is it called a slave cylinder

In engineering, it is used only to describe the functional relationship and subordination of components and has no other negative connotations. Here is a detailed explanation of why it is called a slave cylinder.

1.Master-Slave Relationship: 

In hydraulic systems, including those found in vehicles, there is usually a master component that generates force or pressure, and a slave component that receives this force or pressure and converts it into mechanical action. In the case of a vehicle's clutch system, the master cylinder is responsible for generating hydraulic pressure when the clutch pedal is depressed. The pressure is then transferred to the slave cylinder, which converts the hydraulic pressure into mechanical force to operate the clutch.

2. Historical Engineering Terminology:

The use of the terms “master” and “slave” in engineering dates back to the early days of industrial automation and control systems. These terms are used to describe the relationship between two components, where one component controls the other. For example, in a computer system, there can be a master-slave relationship between a primary hard disk drive and a secondary hard disk drive, where the primary hard disk drive controls the boot sequence and data access.

3. Hydraulic System:

In a hydraulic system, the master component (master cylinder) acts as the controller and the slave component (slave cylinder) executes the commands of the master component. This term is used to describe a hierarchical relationship between two components where the master component directs the operation and the slave component performs the operation.

4. Functional slave properties:

In a clutch control system, the slave cylinder usually exists as a subordinate or auxiliary component that receives the power input from the master cylinder and converts it into a mechanical action on the clutch release mechanism. This subordinate or auxiliary functional characteristics, so that it is called “slave” (slave) cylinder.

5. Power transmission and control:

The main function of the slave cylinder is to transmit the hydraulic or pneumatic power generated by the master cylinder to the clutch release mechanism, thus realizing the control of the contact state between the clutch disc and the flywheel and pressure plate. The slave nature of this power transmission and control is one of the reasons why it is called “slave”.

6. Position in the system structure:

In a clutch control system, the slave cylinder is usually located after the master cylinder as a link in the power transmission chain. This position in the system also reflects its slave or auxiliary character.

Summarization

In summary, the slave cylinder is called “slave” because it plays a subordinate or auxiliary role in the clutch control system, receiving and transmitting power from the master cylinder to realize the control of the clutch release mechanism. This nomenclature not only reflects its functional characteristics, but also conforms to its position in the system structure.