Double Acting Hydraulic Cylinder： Principles, Applications, And Advantages

Double acting hydraulic cylinder is an indispensable key component in hydraulic transmission systems, playing an important role in various industrial fields. Compared with single acting hydraulic cylinders, Double acting hydraulic cylinders can provide thrust and tension in two directions, greatly expanding the functionality and application range of hydraulic systems. This article will delve into the working principle, common applications, and advantages of Double acting hydraulic cylinders compared to other types of hydraulic cylinders.

The core components of Double acting hydraulic cylinder include cylinder barrel, piston, piston rod, sealing element, and two independent oil ports

The working principle of the Kaviri acting power unit is based on Pascal's principle: when hydraulic oil enters the cylinder through an oil port, it applies pressure to the piston, pushing the piston rod to move, thereby achieving linear motion. Unlike single acting hydraulic cylinders, Double acting hydraulic cylinders have two oil ports located on either side of the piston. When hydraulic oil enters from one port, the other port is used to discharge the oil and control the extension of the piston rod; On the contrary, when hydraulic oil enters from another port, the piston rod will retract. By alternately controlling the inlet and outlet of two oil ports, the reciprocating motion of the piston rod in two directions can be achieved.

The application range of Double acting hydraulic cylinder is extremely wide, covering almost all industrial fields that require linear motion

In the field of construction machinery, such as excavators, loaders, etc., Double piston rod hydraulic cylinders are used to control the movement of components such as the boom and bucket to complete excavation, loading, and other operations. In the field of industrial automation, Double acting hydraulic cylinders are applied in automation equipment such as robots and robotic arms to perform precise positioning and control tasks. In the metallurgical industry, Double acting hydraulic cylinders are used to control the roll gap of rolling mills, achieving precise control of steel thickness. In addition, Double acting hydraulic cylinders also play a crucial role in fields such as aerospace, shipbuilding, and petrochemicals.

Compared to single acting hydraulic cylinders, Double acting hydraulic cylinders have significant advantages

Firstly, the double acting hydraulic cylinder can provide power in two directions, making control more flexible and precise. Single acting hydraulic cylinders typically only provide power in one direction, while the other direction requires a spring or other external force to achieve reset. Secondly, Double acting hydraulic cylinders are capable of withstanding larger loads. Due to the hydraulic oil driving the piston rod in both directions, it can withstand greater thrust and tension. Finally, the design of the Double acting hydraulic cylinder is more compact. Compared to single acting hydraulic cylinders that require additional reset mechanisms, Double acting hydraulic cylinders have a simpler structure and occupy less space.

In summary, hydraulic double acting cylinders play an important role in modern industry due to their flexible control performance, powerful load capacity, and compact design. With the continuous development of technology, the design and performance of Double acting hydraulic cylinders are also constantly improving, such as using new sealing materials and improving processing accuracy, so that they can work stably and reliably even under more stringent working conditions. It can be foreseen that Double acting hydraulic cylinders will continue to play an important role in various fields, contributing to industrial automation and intelligence.

Double Acting Hydraulic Cylinder  FAQs

What is a Double Acting Hydraulic Cylinder?

Double acting hydraulic cylinder is an actuator that provides power in two directions (extension and retraction) through hydraulic oil. There are oil ports on both sides of its piston (A port and B port), which achieve bidirectional movement through alternating oil supply and return.

Features: Uniform output, strong controllability, suitable for occasions that require precise reciprocating motion (such as construction machinery, injection molding machines, etc.).

What is the difference between a double acting hydraulic cylinder and a single acting hydraulic cylinder?

Double acting hydraulic cylinder： Both directions are driven by hydraulic pressure and require two oil circuits for control, capable of outputting thrust and tension.

Single acting cylinder: Only one side is driven by hydraulic pressure (usually extended), and the return relies on external forces such as springs and gravity.

Application differences: Single acting cylinders are more commonly used for simple actions such as clamping, while double acting hydraulic cylinders are suitable for scenarios that require active control of back and forth movement.

How to achieve synchronous control of Double acting hydraulic cylinder?

The synchronization methods include:

Mechanical linkage: forced synchronization through gears/linkages.

Diverter valve: evenly distribute flow to multiple oil cylinders.

Servo system: using sensors and closed-loop control to adjust flow in real-time.

Attention: Uneven load or leakage may cause asynchronous operation and require regular maintenance.

What are the seals for Double acting hydraulic cylinders? Why is it easy to leak?

Main sealing components: piston seal (to prevent internal leakage), rod seal (to prevent external leakage), guide ring (to reduce friction).

Reasons for leakage: seal aging, oil contamination, scratching of cylinder/piston rod, pressure impact, etc.

Maintenance suggestion: Regularly replace seals, keep the oil clean, and avoid overpressure operation.

How to calculate the thrust and velocity of a Double acting hydraulic cylinder?

Thrust:

When extended: F ₁=P × A ₁ (A ₁ is the area of the rodless side)

When retracted: F ₂=P × A ₂ (A ₂ is the rod side area, A ₂=A ₁ piston rod area)

Speed:

Extension speed: v ₁=Q/A ₁

Retraction speed: v ₂=Q/A ₂ (Q is flow rate)