Suspension, also known as suspension, is the general name of all force transmission connecting devices between the semi-trailer frame and the axle. It is used to transmit the force and torque acting between the wheel and the frame, buffer the impact force transmitted from the road to the frame or body, and reduce the vibration caused thereby, so as to ensure that the vehicle can run smoothly.

Generally, the suspension of semi-trailer can be divided into four types:

1. Rigid suspension.

The body chassis of rigid suspension directly acts on the axle between the wheels without spring as buffer. In case of uneven road surface, it completely depends on the swing of balance beam to maintain the relative balance of front and rear axles.

This kind of suspension is relatively rare at present, because its damping effect is very poor. It is mainly used in low-speed flat semi-trailer carrying goods.

2. Steel plate suspension.

Also known as series leaf spring balanced suspension, that is, the common leaf spring suspension, which is mainly composed of leaf spring, suspension support, connecting rod, U-bolt, etc.

The biggest advantage of this trailer suspension is low cost, reliable operation and convenient maintenance. Because of this, steel plate suspension is currently the largest application proportion in domestic semi-trailer, about 70-80%.

3. Single point suspension.

That is, the common front and rear supports of leaf springs are reduced to a single support connected to the vehicle body, which can divide the force points equally to different axles, so the bearing capacity is larger, which is generally used on heavy trailers.

4. Air suspension.

Also known as airbag suspension, its most remarkable feature is the airbag air spring. Compared with other suspensions, the cushioning force of air suspension is better, which can effectively protect goods and improve driving comfort. At present, it is mainly used in the transportation of precision instruments and dangerous chemicals.

According to the technical conditions for safe operation of motor vehicles gb7258-2017, three axle barrier plate and warehouse grid semi-trailer must be equipped with disc brake and air bag suspension in order to get on the license plate or drive on the road smoothly. So what are the advantages of air suspension?

Advantages of air suspension:

1. Good shock absorption effect. Compared with the traditional leaf spring, the air bag is obviously softer and more comfortable. It forms a soft connection between the frame and the axle. The bumps and impacts from the road can be alleviated to a great extent. In addition to enhancing driving comfort, it is also a kind of protection for goods.

2. Reduce load stress. The compressibility of the air makes the air bag suspension easy to deal with the bumps of the road, reduce the load stress, prolong the service life of the axle and semi-trailer, and reduce the vehicle cost to a certain extent.

3. Its own weight is smaller. Lightweight is a development trend of trailer accessories industry at present. Compared with traditional suspension, air suspension has lighter weight and can obtain more spare weight space for standard load users, while no-load users can save fuel, save energy and increase efficiency.

4. Long service life. The air spring itself is light in weight, and the air medium friction in the airbag is relatively small. The service life can reach 2-3 times that of the leaf spring, helping the owner to better save costs.

Air suspension has many advantages, but there are also some disadvantages objectively:

1. Compared with other suspensions, the structure of air suspension is more complex, because to use air spring, it is necessary to set up a bar system that can transmit various forces and moments other than vertical force, which also leads to its high price to a certain extent.

2. Corresponding to the high price is the maintenance cost. In addition, compared with the traditional leaf spring, the airbag is easier to be damaged in material, and the maintenance cost can not be underestimated.

3. Once the air suspension fails, it cannot continue to drive and can only be called for trailer service. Unlike the traditional suspension, even if there is an oil leak, you can stick to the maintenance network.

4. The air suspension has good cushioning, but it will nod or tail when braking or starting under full load, and skilled driving skills are also required.

Although the advantages and disadvantages of air suspension coexist, the advantages are more obvious under comprehensive consideration. Otherwise, air suspension will not become an official mandatory suspension. In addition, "lightweight" is popular in the commercial vehicle industry, shippers pay more and more attention to cargo damage, and the competition among peers is becoming more and more fierce. This industry background also promotes the use of air suspension to a certain extent.

It is recommended that car owners choose reliable brands when purchasing air suspension, which can also reduce the cost of subsequent maintenance and replacement to a certain extent. The air suspension produced by Darong machinery is composed of air spring, shock absorber, height control valve, guide arm and follow-up steering mechanism. It adopts 3D forming technology with stronger bearing capacity. The special seal can fully ensure the temperature of the suspension during operation, prolong the service life, make the part assembly design more flexible, shorten the installation time, and carry out maintenance according to the actual situation, Reduce maintenance costs.