Pressurized oil drives the piston in the cylinder to move upward. When a fixed structure is positioned above the cylinder’s chamber, it can function as a press. As the oil returns to the reservoir through an open oil circuit, the cylinder’s piston descends, relieving pressure.

Hydraulic cylinder It converts hydraulic energy into mechanical energy and produces linear reciprocating motion. ( or oscillatory motion ) Hydraulic actuators feature a simple structure and reliable operation. When used to produce reciprocating motion, they can eliminate the need for speed-reducing mechanisms, exhibit zero transmission backlash, and deliver smooth motion, making them widely employed in various mechanical hydraulic systems. The output force of a hydraulic cylinder is directly proportional to the effective area of the piston and the pressure differential across its two sides. A typical hydraulic cylinder consists of a cylinder barrel and cylinder head, a piston and piston rod, sealing elements, cushioning devices, and venting devices. While cushioning and venting devices depend on the specific application, other components may also be required.

Hydraulic cylinder Structurally, it can be divided into a piston cylinder. Plunger cylinders and oscillating cylinders. Cylinders can be structurally classified into piston cylinders. Thin-film cylinder Telescopic cylinder. Hydraulic cylinder Its operating principle is as follows: To explain how it works, let’s first take a look at its five basic components. ，1 , cylinder and cylinder head; 2 , piston and piston rod; 3 , sealing device; 4 , buffer device; 5 , exhaust device. Each cylinder operates in a similar manner; the hydraulic cylinder is pressurized manually via a valve stem. ( Hydraulic hand pump ) Hydraulic fluid enters the cylinder through a single valve. Due to the check‑valve action, the fluid cannot flow back, forcing the piston rod to move upward. Subsequently, hydraulic fluid continues to be supplied to the cylinder during operation, enabling continuous reciprocating motion. When the cylinder descends, the hydraulic valve is opened, allowing the fluid to return to the reservoir. This constitutes a basic operating principle; all other configurations are built upon this foundation.

The principle of a cylinder is similar to that of a hydraulic cylinder.

1. Since the pressure in pneumatic systems is generally around 0.2-1.0Mpa Within this range, pneumatic cylinders cannot be used as high-power actuators. Hydraulic cylinders, on the other hand, can serve as relatively high-power components when integrated into a hydraulic system.

2. From the perspective of the working medium, air is abundant and inexhaustible. It is inexpensive and readily available, and the gas used is discharged directly into the atmosphere, making disposal convenient and environmentally benign. Hydraulic oil, by contrast, presents the opposite situation.

3. Air has low viscosity, resulting in lower resistance compared to hydraulic oil.

4. The compressibility of air is much greater than that of hydraulic fluid, resulting in significantly poorer operational stability and responsiveness.