The valve core of a hydraulic cylinder is the core component that controls the flow direction, pressure and flow rate of the hydraulic oil inside the cylinder. It is usually installed inside the valve body and changes the on-off and opening degree of the valve port by moving or rotating, thereby achieving precise control of the hydraulic cylinder's operation. Classification by structural form

Slide valve
Structure: It is composed of a cylindrical valve core and a valve sleeve. The valve core slides axially within the valve sleeve and forms different oil port connection states with the grooves on the valve sleeve through the shoulder.
Application: Commonly seen in directional control valves, such as two-position four-way and three-position four-way slide valves, they are used to control the flow direction of hydraulic oil, enabling the forward, backward or stop movement of hydraulic cylinders.
Cone valve
Structure: The valve core is conical in shape and fits with the conical surface of the valve seat for sealing, providing excellent sealing performance. It is often used in pressure valves (such as relief valves and sequence valves) or flow valves.
Features: When the valve core operates, it cuts off or conducts the oil passage through conical surface contact, has strong pressure-bearing capacity and low leakage.
Ball valve
Structure: The valve core is a sphere. It controls the opening and closing of the oil port by rotating the sphere and is often used in on-off valves or small hydraulic systems.
Features: Flexible operation, excellent sealing performance, but relatively low flow regulation accuracy.

2. Classification by function

Directional control valve core: Controls the flow direction of hydraulic oil and changes the movement direction of the hydraulic cylinder.
Pressure control valve core: Such as the valve core of a relief valve, by adjusting the spring force to balance with the hydraulic pressure, it controls the system pressure not to exceed the set value.
Flow control valve core: Such as the valve core of a throttle valve, it regulates the flow by changing the opening degree of the valve port and controls the movement speed of the hydraulic cylinder.