1. The rubber damping and materials of damping rubber
Rubber is characterized by both high elasticity and high viscosity. The elasticity of rubber is produced by changes in the conformation of its crimped molecule. The interaction of rubber molecules can impede the movement of molecular chains and show the characteristics of viscosity, so that the stress and strain are often in an unbalanced state. The long curved molecular structure of rubber and the weak secondary forces between the molecules make the rubber materials exhibit unique viscoelastic energy, thus having good shock absorption, sound insulation and buffering properties. Rubber components are widely used to isolate vibration and absorb shock, because they have the characteristics of hysteresis, damping and large reversible deformation.
The hysteresis and internal friction characteristics of rubber are usually expressed by loss factor. The larger the loss factor, the more significant the damping of rubber, the more obvious the shock absorption effect. The size of the loss factor of rubber material depends not only on the structure of rubber itself, but also on temperature and frequency. At room temperature, the loss factor of natural rubber and cis-butadiene rubber is relatively small, the loss factor of styrene rubber, chloroprene rubber, ethylene-propylene rubber, polyurethane rubber and silicon rubber is medium, and the loss factor of butyl rubber and NBR is the largest.
There are 5 kinds of rubber materials used for shock absorption, namely general rubber materials, oil resistant vulcanizate, weather resistant vulcanizate, high-damping vulcanizate, heat-resistant vulcanizate. Although the loss factor of natural rubber is small, it has the best comprehensive performance, excellent elasticity, good fatigue resistance, good bonding performance with metal parts, good electrical insulation and processing performance. Natural rubber is therefore widely used for shock absorption purposes. When low temperature or weather resistance is required, it can be blended with or blended with polybutadiene rubber or chloroprene rubber. Silicone rubber is often used as damping rubber for demanding low temperature dynamic performance. IIR or halogenated IIR can be used when high damping is required. Polyurethane rubber has excellent abrasion resistance, flexural flexibility and resistance to hydrocarbon fuels and most organic solvents. Polyurethane rubber is also widely used in shock absorption and sound insulation.
2. Development and application of shock absorbing rubber products
Rubber shock absorber commonly known as rubber vibration dampening mounts. There are many kinds of rubber shock absorber, which can be divided into compression type, shear type, torsional type, impact type and mixed type. With the development of science and technology, more and more kinds of rubber shock absorbers are available, and their applications are more and more extensive.