Gas Spring Working Principle, Types, and Installation Guide
- How Does a Gas Spring Work?
- What Roles Do Nitrogen, the Piston, and Oil Play?
- What Is the Difference Between a Gas Spring and a Traditional Coil Spring?
- Main Types of Gas Springs
- Differences Between Gasoblock and Gasohite
- Working Temperature Range of Gas Springs
- Gas Spring Installation Guidelines
- What Factors Affect the Service Life of a Gas Spring?
- Why Does a Gas Spring Lose Force?
- Gas Spring Disposal and Safety Handling
- FAQ
- Tong Da’s Role in Gas Spring Manufacturing Equipment
How Does a Gas Spring Work?
A gas spring, also known as a gas strut or gas lift support, is a mechanical component that uses compressed gas inside a sealed cylinder to generate force.
Its working principle is similar to a compression spring, but the force does not come from the deformation of a metal coil. Instead, it comes from high-pressure gas pre-filled inside the cylinder.
Most gas springs are filled with nitrogen. When the piston rod and piston move inside the sealed cylinder, the gas pressure acts on the piston structure. Because the effective pressure area on each side of the piston is different, an outward force is generated to push the piston rod.
This is the reason why gas springs can support automotive tailgates, furniture panels, machine covers, medical equipment, and other movable structures.
What Roles Do Nitrogen, the Piston, and Oil Play?
The performance of a gas spring mainly depends on the combination of compressed nitrogen, the piston structure, and a small amount of oil inside the cylinder.
Compressed Nitrogen Provides the Main Force
The main force of a gas spring comes from compressed nitrogen inside the sealed cylinder.
Nitrogen is stable, inert, and less likely to react with internal components, making it suitable for gas spring applications.
When the gas spring is compressed, the internal gas volume changes, and the pressure changes accordingly. This pressure variation affects the output force of the gas spring.
The Piston and Valve Structure Control Movement
The piston is located inside the pressure cylinder and moves together with the piston rod.
Some gas springs use piston holes, valves, or flow channels to control the flow speed of gas or oil. This affects how the gas spring moves during extension and compression, including its speed, resistance, and operating feel.
A Small Amount of Oil Provides Lubrication and End Damping
A small amount of oil is usually added inside the cylinder.
This oil helps provide lubrication, supports sealing performance, and creates damping at the end of the stroke. It reduces impact loads on hinges, mounting points, and surrounding structures during opening or closing.
With proper installation, many gas springs can provide smoother end-position damping and a more stable operating feel.
What Is the Difference Between a Gas Spring and a Traditional Coil Spring?
Both gas springs and traditional coil springs can provide elastic supporting force, but their force characteristics are different.Traditional Coil Spring
A traditional coil spring generates reaction force only after it is compressed.
Its force usually increases as the compression stroke increases, creating a more linear relationship between force and stroke.
Gas Spring
A gas spring can provide relatively high supporting force from the beginning of the stroke. Its force curve is also flatter and more stable throughout the stroke.
This makes gas springs easier to apply in opening, supporting, and damping applications, especially where smooth operation and controlled movement are required.
Compared with traditional coil springs, gas springs offer several advantages:
Main Types of Gas Springs
Gas springs can generally be divided into two main types based on their function: non-locking gas springs and locking gas springs.Non-Locking Gas Springs
A non-locking gas spring usually remains in an extended position when no external force is applied.
This type of gas spring is mainly used for opening assistance, support, and reducing operating force.
Common applications include:
The main feature of a non-locking gas spring is its simple structure and wide range of applications. However, it cannot be forcibly locked at any position along the stroke.
In some product categories, this type of non-locking gas spring may also be referred to as a Gasolift type.
Locking Gas Springs
A locking gas spring can be locked at a specific position or at any position along the stroke. It is suitable for applications that require angle adjustment, position holding, or height control.
This type of gas spring usually includes an internal valve mechanism. When the valve is opened by an external lever, button, or operating mechanism, the piston rod can move. When the valve is closed, the gas spring locks and holds the required position.
Common applications include:
Differences Between Gasoblock and Gasohite
Some locking gas springs can be further classified by valve position and operating method.Gasoblock
In a Gasoblock type gas spring, the valve is usually located on the piston rod side and is operated by an external mechanism.
Depending on locking rigidity and force direction, Gasoblock products may include elastic locking, rigid locking in extension, or rigid locking in compression.
Common applications include:
Gasohite
In a Gasohite type gas spring, the valve is usually located in the tube assembly and is operated from the top of the cylinder.
This type is commonly used in chair height adjustment and swivel mechanisms.
Common applications include:
How to Choose Between Gasoblock and Gasohite
The selection should be based on the following factors:
Working Temperature Range of Gas Springs
The output force of a gas spring is affected by temperature. Because gas pressure changes with ambient temperature, the product specification must be carefully considered when a gas spring is used in high-temperature or low-temperature environments.Common working temperature ranges include:
Gas Spring Installation Guidelines
Correct installation directly affects the operating stability and service life of a gas spring.1. Install with the Piston Rod Facing Down
For general gas springs, it is recommended to install the piston rod facing downward.
This helps keep the seals lubricated and allows the internal oil to provide better damping at the end of the stroke, which can help extend service life.
However, some rigid locking gas springs are not limited by this installation direction and can be installed in different orientations depending on product design.
2. Avoid Damage to the Piston Rod Surface
The piston rod surface should be kept away from contaminants such as:
These contaminants may damage the seals and cause gas leakage, sticking, or shortened service life.
For this reason, it is recommended to install gas springs at the final stage of the assembly process.
3. Reduce Side Load
A gas spring is mainly designed to withstand axial force. It should not be subjected to excessive side load for long periods.
Poor installation angle or misaligned mounting points may cause uneven wear on the piston rod, seal damage, or unstable movement.
4. Keep Mounting Joints Moving Smoothly
For eyelet-type mounting, the pin should have enough freedom of movement and be properly lubricated.
For ball joint mounting, the ball stud should be correctly tightened to prevent looseness or abnormal movement.
5. Pay Attention to Valve Clearance on Locking Gas Springs
For Gasoblock and Gasohite types, the valve actuator should not be preloaded.
There should usually be a proper clearance between the operating rods, such as at least approximately 1 mm. This prevents the valve from staying partially open, which could affect locking performance and service life.
6. Do Not Heat or Disassemble a Gas Spring
A gas spring contains high-pressure gas. It should not be heated, cut, struck, or disassembled without proper safety procedures.
Incorrect handling may cause serious danger.
What Factors Affect the Service Life of a Gas Spring?
The service life of a gas spring depends on product design, sealing quality, operating frequency, load conditions, installation method, and working environment.Common factors include:
Why Does a Gas Spring Lose Force?
A gas spring may lose force because nitrogen gradually leaks in very small amounts over time, causing internal pressure to decrease.This is a normal phenomenon that may occur after long-term use.
A gas spring usually needs to be replaced when the following conditions occur:
Gas Spring Disposal and Safety Handling
A gas spring contains high-pressure gas. Before disposal, it should be handled according to proper safety procedures. It should not be cut, burned, or dismantled directly.General disposal principles include:
FAQ
Q1：How long can a gas spring last?
The service life of a gas spring depends on operating frequency, load conditions, installation method, and working environment.
Under normal use, a gas spring can withstand many operating cycles. However, high temperature, corrosive environments, excessive side load, or improper installation can shorten its service life.
Q2：Can a gas spring be refilled when it loses force?
Most general gas springs are not recommended for user refilling.
When internal nitrogen leakage causes a clear reduction in force, replacement is usually the proper solution.
Q3：Can a gas spring be installed horizontally?
Yes. However, for general gas springs, installing the piston rod facing downward is recommended to extend seal life and maintain better damping performance.
Some rigid locking gas springs can be installed in different orientations depending on their design.
Q4：How do I choose the correct gas spring specification?
When selecting a gas spring, the following factors should be considered:
It is recommended to provide actual dimensions and application conditions to the manufacturer or equipment supplier for proper selection.
Q5：What applications are suitable for locking gas springs?
Locking gas springs are suitable for products that require holding, positioning, or angle adjustment, such as office chairs, medical beds, dental treatment chairs, adjustable seats, and special equipment structures.
Q6：How do I choose between Gasoblock and Gasohite?
Gasoblock is usually suitable for applications that require an external lever to trigger locking or release, such as medical beds, seat backrests, or adjustable furniture.
Gasohite is commonly used in chair height adjustment and swivel lifting mechanisms.
Tong Da’s Role in Gas Spring Manufacturing Equipment
The quality of a gas spring depends not only on internal gas and sealing components, but also on the quality of the metal tube processing.The end forming, tube sealing, necking, dimensional accuracy, and process stability of the pressure cylinder all affect the final product’s pressure resistance, air tightness, and service life.
Tong Da Precision Enterprise Co., Ltd. has long provided tube sealing machines, tube end forming machines, tube wrapping machines, and customized-purpose machinery. These technologies can be applied to the manufacturing processes of gas springs, tailgate struts, gas lift supports, pressure containers, and other precision tube products.
If you would like to learn more about tube processing equipment for gas spring manufacturing, please refer to Tong Da’s tube sealing machines, tube end forming machines, and customized automation equipment solutions.