Since the introduction of GB7258 "Technical Conditions for Motor Vehicle Operation Safety", the installation frequency of air suspension on three axle barrier plate and cage type semi-trailer has become higher and higher. Compared with the traditional leaf spring suspension, the air suspension has the advantages of light deadweight and good weight reduction effect. It can not only improve the ride comfort of the vehicle, but also realize the free lifting of single or multiple axles.

Relatively, the air suspension uses air as the medium, and its shock absorption performance is really excellent. To a certain extent, its rigidity becomes worse. It has very strict restrictions on the transportation weight, and its materials are more easily damaged. Its anti roll ability is relatively weak, so it is not suitable for complex working conditions.

Then, can we find a suspension that can not only achieve the damping effect of air suspension, but also take into account the use needs of bearing capacity and complex road conditions? Hydro pneumatic suspension came into being.

The hydro pneumatic suspension is not a new product. It came out as early as the 1960s. It was first applied to the landing gear of aircraft to improve the stability of aircraft landing. Later, it gradually expanded to military special vehicles and engineering vehicles, as well as heavy vehicles in Germany and Japan.

Hydropneumatic suspension is a special kind of air suspension. It uses the inert gas in the accumulator as the elastic element, the oil in the system as the medium for transmission of force, and the damping hole and one-way valve assembly as the damping element. Through the pressure change of the inert gas in the system, it automatically adapts to the complex working conditions of the vehicle during driving. The flow distribution system uses the flow of oil to achieve the functions of balancing axle load, damping vibration and adjusting the body height.

It can also be said that the hydro pneumatic suspension is a combination of damping elements and air suspension, which is safer and more reliable than the current general air suspension.

What are the advantages of hydro pneumatic suspension?

1. Good shock absorption performance: the hydro pneumatic spring can ensure the constant height of the compartment, reduce the shaking caused by vehicle bumps, reduce the impact on the cargo box, protect the safety of goods, and also extend the service life of the vehicle.

2. Enhance the protection of tires and other accessories: The hydro pneumatic suspension can more effectively absorb the vibration caused by uneven roads, reduce the distortion and impact of the vehicle during driving, and provide good protection for the axle, axle, tire, frame, cargo box, etc.

3. Better economy: The economy of hydro pneumatic suspension is mainly shown in reducing tire wear and fuel consumption. The shock absorption stress of hydro pneumatic suspension is almost zero, which can minimize tire loss. Under the same road conditions and load, the fuel consumption per hundred miles can be reduced to more than 1.2L.

4. The safety is improved: the hydro pneumatic suspension transport is more stable, the center of gravity is almost unchanged when the vehicle is driving, and the axial and radial stability is good. The use of hydro pneumatic suspension can also effectively avoid the forward tilting impact of the vehicle during emergency braking, avoid the vehicle from rolling when turning at high speed, and can significantly inhibit the vehicle's tail flick under slippery conditions such as rainy and snowy weather.

5. The bearing capacity is improved: the hydro pneumatic suspension has a large energy storage ratio and a small dynamic load coefficient, which can withstand greater load impact under the same rated load and better cope with sudden impact peak.

6. Longer maintenance cycle: according to relevant statistics, the service life of the hydro pneumatic suspension can be about 20% longer than that of the air suspension. In addition, the maintenance cycle is also longer, which can improve the utilization efficiency of the vehicle.

Some car owners may have asked: Is there no defect in hydro pneumatic suspension? There are both advantages and disadvantages. No matter how many advantages the hydro pneumatic suspension has, there are still disadvantages. The most intuitive one is the purchase and maintenance costs. It is understood that if a three axle semi-trailer is fully equipped with hydro pneumatic suspension, its cost will be about 50000 to 60000 yuan. Due to its special structure, the subsequent maintenance cost cannot be underestimated, which may be the most important factor restricting the development and application of hydro pneumatic suspension.