Development and Application of Shock-absorbing Rubber Products
With the rapid development of modern industry, vibration and noise have become serious problems in various fields: it will reduce the operating accuracy and affect product quality; it will shorten the life of the product, making high-precision instruments unable to work normally; endangering safety, making equipment or structures Early damage; pollute the environment and affect human health, such as earthquakes and other shocks even cause great damage to human life and property. Therefore, the research and mastery of vibration control and noise control technology has become a major issue facing the industrial development of various countries.
The most fundamental and best way to eliminate vibration and noise is to reduce or eliminate the vibration of the vibration source, but in fact it is impossible to completely eliminate the vibration of the vibration source, so other methods of controlling vibration must be adopted. The most extensive and effective method in practical application is to use various shock-absorbing products, especially rubber shock-absorbing products. It can effectively isolate the vibration and the excitation source, and can also ease the vibration of the vibrating body, so it is widely used in the vibration isolation of various motor vehicles, aircraft, ships and other power machinery, fans, water pumps and other auxiliary equipment and instruments. In recent years, some large buildings and bridges have also adopted laminated rubber mats for earthquake isolation to support buildings. For the damping treatment of structural vibration and structural noise, special rubber materials, called viscoelastic high damping materials, are also widely used.
Rubber is characterized by both high elastic state and high viscous state. The elasticity of rubber is produced by the change of its coiled molecular conformation. The interaction between rubber molecules will hinder the movement of molecular chains, and it also shows viscosity characteristics, so that stress Often out of balance with strain. The curly long-chain molecular structure of rubber and the weaker secondary force between molecules make the rubber material exhibit unique viscoelastic properties, so it has good shock absorption, sound insulation and cushioning properties. Rubber parts are widely used to isolate vibrations and absorb shocks because of their hysteresis, damping, and ability to undergo large reversible deformations.
There are generally 5 types of rubber materials used for shock absorption, namely NR, SBR, and BR are ordinary rubber materials; NBR is used for oil-resistant vulcanized rubber; CR is used for weather-resistant vulcanized rubber; IIR is used for high damping vulcanized rubber; Heat resistant vulcanizate. Although NR has a small loss factor, it has the best overall performance, excellent elasticity, good fatigue resistance, low heat generation, small creep, good adhesion to metal parts, cold resistance, electrical insulation and processing performance. , so NR is widely used for shock absorption purposes, and when low temperature resistance or weather resistance is required, it can be used in combination with BR or CR or blended for modification. Nishiue et al. used NR, BR and metal salts of organic acids containing -OH groups with more than 4 carbon atoms to make shock absorbers with good durability. The permanent deformation is 17.0% and 11.7%, respectively. Due to its excellent properties such as weather resistance, ozone aging resistance, electrical insulation, heat resistance and cold resistance, EPDM has attracted extensive attention in recent years.
Development and Application of Shock-absorbing Rubber Products
Rubber shock-absorbing products are generally also called rubber shock absorbers. There are many types of rubber shock absorbers, which can be divided into compression type, shear type, torsional vibration type, impact type and hybrid type from the perspective of the vibration force. With the development of science and technology, there are more and more types of rubber shock absorbers, and their uses are becoming wider and wider. The following is an overview of the development and application prospects of rubber shock absorbers from the application fields.
Automotive Rubber Shock Absorber
With the development of social economy, the modification and replacement of domestic and foreign automobiles is quite frequent, and the automobile industry is facing a period of rapid change. The development is characterized by ensuring driving safety, riding comfort, high-speed driving and luxury. , Further improve the service life of the car. Shock-absorbing products are used to control the vibration and noise of the car and improve its handling stability. They are generally placed in the car engine frame, pressure bar device, suspension bushing, center bearing bracket, jolt limiter and torsional shock absorber. , to improve the safety and comfort of the car. Shock-absorbing products can be divided into four categories: brackets, bushings, cushioning and damping. The main requirements are good shock absorption, heat resistance and fatigue resistance. Automotive shock-absorbing rubber products include engine mounts, suspension components, rubber springs, rubber air springs, and collision rubber protectors. In recent years, in order to improve the safety, comfort and operability of automobiles, the variety and quantity of shock-absorbing rubber products for automobiles have been increasing. For example, the number of shock-absorbing rubber products on a car has reached 50-60 pieces.
3 Rubber damping system for railway locomotives and railway sleeper pads
The shock-absorbing rubber products on the railway locomotive mainly include the central support rubber stack, the axle box pull rod rubber spring body, the side bearing rubber stack, the motor suspension rubber pad, the elastic wheel, the elastic gear, the rubber air spring, the bow rubber block of the transmission device and Rubber ball hinge, coupler rubber buffer, etc. The rubber shock absorber applied to locomotives is mainly used to bear compressive stress, shear stress and torsional moment, and to bear the compound action of two or more stresses at the same time.
4. Rubber shock absorbers for bridges
In bridge engineering, supports are required at both ends of the span of a girder bridge. The main function of the support is to reliably transfer all the loads on the bridge span structure (including dead load and live load) to the bridge piers, and to withstand the horizontal displacement and rotation angle deformation of the end of the bridge span structure due to the load; The second is to adapt to the expansion and contraction caused by changes in temperature and humidity. There are two types of bridge supports: fixed and movable supports. The former is to fix the position of the bridge span structure on the pier, so that the end points of the bridge span structure can rotate freely without moving; the latter not only allows the end fulcrum to rotate freely but also requires It can move freely and bear the bridge span structure due to factors such as temperature changes, concrete shrinkage and loads. Introduced abroad, rubber bearings began to be used in the late 1950s. By the 1960s, many countries in the world had applied them. Compared with other rigid bearings, bridge rubber bearings not only have reliable working performance, but also have the advantages of simple structure, sufficient material sources, and easy processing and manufacturing. Because rubber bearings can adapt to the deformation of the superstructure of wide bridges, curved bridges and oblique bridges in all directions, it is not only widely used in small and medium-span highway bridges, urban bridges and railway bridges, but also in large-span bridges. It is also heavily used on bridges.
5. Rubber shock absorbers for construction engineering
Due to unavoidable natural disasters such as earthquakes, the construction of buildings and structures resistant to strong earthquakes is an important topic in the field of construction engineering. At the same time, the increasing traffic density leads to greater vibration transmission and noise pollution, and the vibration and noise isolation of civil construction has become an urgent problem to be solved.
Since the United States took the lead in using vibration-isolation rubber bearings in the Abani Building in 1966, Japan, France, New Zealand and my country have also successively used vibration-isolation rubber bearings in some important buildings. Among the base isolation buildings currently built, more than 80% of the buildings use laminated rubber isolation bearing systems to resist earthquakes. Laminated rubber bearings are not only widely used in bridge construction projects, but also have been used in the base of buildings to isolate seismic sources, earthquake protection and seismic isolation of buildings in water areas. Practice has proved that these buildings using seismic isolation rubber bearings can withstand strong earthquake tests. The buildings of this system have shown excellent anti-seismic effect, not only the buildings have not collapsed, but also the internal facilities have not been damaged.
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