Rubber air spring partition design and performance

Rubber gas springs are curved airbags made of rubber and cord. The two sides of the capsule can be connected with two steel plates to form a closure that forms a compressed air chamber. The rubber and cord have no load-bearing capacity of their own and are supported by compressed air filled in the capsule. It is relied upon changing the pressure of the compressed air in it to obtain the required rigidity. At present, the application of rubber air springs has been very mature in China, especially in the application of high-precision instruments and industrial equipment and vehicles.

1. The working principle of rubber air spring
Rubber air spring is a kind of air pressure vibration isolator. In the realization time interval, the displacement change does not change with the addition of environmental load, that is, it has the characteristics of zero compression. When the rubber gas spring acts, it is filled with high-pressure gas (internal pressure less than 0.7 MPa), and a series of gas columns formed under high pressure appear. The load capacity increases, so that the spring is shortened, the internal volume is reduced, the rigidity of the spring is increased, and the effective bearing area of the gas column inside is increased. When the load capacity decreases, the length of the spring will increase, the volume of the internal cavity will increase, the stiffness of the spring will weaken, the effective bearing area of the air column in the chamber will decrease, and the load-bearing capacity of the spring will decrease. Under the effective impact of the air spring, the height of the cavity, the volume of the cavity and the bearing strength of the air spring will be transmitted normally and flexibly. This is a very convenient vibration isolator.

2 Design and application of rubber air springs
2.1 Design of rubber air springs
1) The size of the tension of the gas spring mostly depends on the shape and material of the internal structure. When choosing rubber with different compositions, we need to consider many things, first of all, we must understand the properties of the main materials, and there are requirements for the mechanical properties of rubber starting from the general deformation structure, so as to withstand the stress deformation of various parts and the shear stress caused by compression.

2) The continuous elongation stress of rubber composites mainly indicates the stress and strain capacity characteristics of rubber air spring dampers. Therefore, elongation stress is often used as an indicator of the mechanical function of rubber compositions. Carbon black is used as a reinforcing component of rubber air springs, which can strengthen the constant tensile stress of rubber materials, and reduce the dynamic deformation and compression deformation of rubber materials under constant load, so that the heat generation is greatly reduced. Although the type of raw rubber used varies, the tensile stresses on the rubber layer of each component must be properly distributed.

3) The initial vibration isolation function of the rubber vibration isolation system is to reduce the vibration of the middle and high frequencies below the intended value. In the case of low-frequency vibrations, it is possible to test the use of damping and adjust it to the hypothetical value of low vibration. Because of its own shortcomings, there is no way to drop too much for many low amplitudes and some ultra-low amplitudes, which cannot be changed, and are brought about by their own characteristics.

4) The design of rubber gas springs is different in different equipment or vehicles. For example, in order to reduce the vibration of large trucks and improve the comfort of truck drivers, the researchers carried out a separate design of the rubber air spring of the truck, and finally adopted a matching electromagnetic device through the analysis of the obtained test data, which can reduce the original vibration amplitude of the rubber air spring to the lightest. Moreover, in its design, a unique sequencing measure is adopted, and the vibration amplitude can be absorbed by such a design. It is recommended to use the rubber cord capsule as the base part and design it as the upper vibration damping element].

2.2 Application of rubber air spring
(1) Maglev train is a new type of non-ground contact vehicle, which has the advantages of high speed, low sound and energy saving, and has attracted much attention. In this regard, the use of rubber gas springs is quite important. The Rolling Stock Research Institute has developed membrane and band rubber gas springs for steering system brackets for SYS130A and SYS130B maglev trains. The application of these types of rubber air springs to the central suspension of maglev trains can improve the riding stability of maglev trains and promote the application and research and development of maglev trains in China. The trains of China's Badaling Travel Development Line use air springs manufactured by NEWAY, which use liquid shock absorbers and have no extra air chambers to reduce their volume and weight. The use of rubber air springs improves the quality of the vehicle's auxiliary suspension, increasing its smoothness and durability.

(2) Rubber air springs are widely used in industrial equipment. Because of the breakthrough of China's industrial technology, many advanced equipment and technologies have been put into use, and the use of rubber air springs has also increased. In most machine damping methods, rubber air springs are often constructed in two ways: bound diaphragm and free diaphragm. Rubber air spring in the installation of this mechanical equipment to cushion shock absorption, control swing or provide pressure technology function, compared with other vibration isolation mechanism of the same effect, rubber air spring structure system, no seal leakage risk, material pollution to the environment is small,
waste disposal is convenient, and the use time is longer.

(3) Rubber air springs have been widely used in the field of vehicles. The use of air springs in some buses, heavy trucks, and high-performance commercial vehicles has occupied a high proportion, and according to the planning requirements of China's automobile industry, the design of large vehicles should meet the requirements of certain protection for highways. It has been stipulated that the rear axle of dangerous goods transport vehicles with a total mass of 12 000 kg or more, all dangerous goods transport semi-trailers, as well as three-axle steeplechase and stake semi-trailers shall be equipped with air suspension.

3 Performance of rubber air springs
(1) Rubber air springs can be designed separately, with good spring height and bearing capacity design space, as well as the characteristics of extremely soft springs.
a. Spring height. The use of load-bearing sensing valves makes it easy to control the height of the gas spring and maintain a certain height when it bears weight fluctuations.

b. Good ability to bear load. Rubber gas springs can obtain a lot of weight by changing their internal pressure, and the size of this load is approximately proportional to the pressure inside the component. The rubber air spring can meet the requirements of a variety of loads, so the economy is relatively good, and the position of the rubber air spring can bear the load of 45~4 500 kg.

(2) Spring rate. Under different load conditions, its stiffness can be solved according to the change in internal air pressure. The stiffness is approximately proportional to the pressure inside the member, so we can choose any stiffness we need. As for a certain size of rubber air spring, its stiffness can also change, and change with the change of weight, so under each load, the natural frequency is probably stable, so that the support system can have a more stable function.

(3) The original vibration frequency is relatively low. Its parts are connected with an air chamber of Yiduojia, which can reduce the original vibration frequency of its equipment to 0.5~3 Hz.

(4) The air damping effect is mainly used to add an opening between the rubber air spring and the available space inside, when the spring carries vibration, the air passes through the opening, so that more energy is lost, thereby reducing vibration.

(5) It can be used for a longer time, and the wear resistance of rubber gas springs is better than that of metal springs. The stress test of the suspension shows that the leaf spring breaks after 100,000 vibrations, while the rubber air spring does not break after more than 5 million vibrations at 40 mm amplitude and 2.7Hz frequency, so its durability is much higher than that of metal springs, reducing maintenance costs and improving the safety performance of its equipment.

(6) Rubber air springs, like anti-vibration rubber, have good support and anti-vibration effects in the axial and rotational directions.

(7) The production and assembly of rubber air springs use less funds and materials, which are easy to assemble and replace, and do not require frequent maintenance.

4 Conclusion
At present, the design and development of this technology in China is relatively mature, and the component design technology has approached the level, and its types are more and more, and it has been widely used. Although rubber air springs are more complex in structure than general vibration isolators in China, they require little capital and materials, and the equipment is easy to replace, easy to overhaul, and does not require frequent repairs. These advantages make rubber gas springs more feasible when they are used in everyday machines or some high-precision instruments and vehicles.
It is believed that with the development of science and technology, rubber air springs with better functions than ordinary vibration isolators will be likely to be widely used in more products. Rubber air springs are very promising in China, and there is a lot of room for development; It is believed that with the efforts of relevant technicians, the design of rubber air springs will have a qualitative breakthrough.