Oil-free bearings mainly include gas smooth bearings, composite material smooth bearings, water smooth bearings, etc.
1. Gas smooth bearing:
Gas smooth bearing is a sliding bearing that uses gas as a smoothing agent. The most commonly used gas smoothing agent is air, and nitrogen, argon, hydrogen, helium, etc. can also be used as needed. The mechanism of the gas-smooth bearing to form the bearing gas film is the same as that of the liquid-smooth bearing.
Gas-smooth bearings make use of gas transmission, diffusion, viscosity and thermal conductivity, adsorption and compressibility. Make it between the conflicting pairs, under the action of fluid dynamic pressure effect, static pressure effect and kneading effect. An intact air film has the function of supporting loads and reducing conflicts.
Gas smooth bearings are generally divided into three types: gas dynamic pressure bearings, gas static pressure bearings and gas kneading bearings. The actual smoothness of the bearing often exists in the form of dynamic and static pressure, dynamic, kneading, static, kneading, and a mixed smooth state of dynamic, static and kneading. The mechanism of the gas-smooth bearing to form the bearing gas film is the same as that of the liquid-smooth bearing.
2. Composite smooth bearing
Because of the requirements of special production technology, some key equipment of industrial and mining enterprises operate under extremely harsh working conditions. Because the equipment is heavy, the ambient temperature is high, the dust is large, or the air contains acidic corrosive gases, etc.
There are many problems to the smoothness of the equipment, and the conflict and wear are severe. Most of them still use traditional oil and grease for smoothness. In fact, these industrial and mining conditions have exceeded the scale of oil and grease smoothness. Bearings and other conflicts are prone to occur. Bites or bites. Causes severe wear and damage of parts, often resulting in equipment shutdown.
The composite material selected for the composite lubricating bearing is a new type of extreme pressure resistant solid lubricating material, which is composed of a metal substrate and a solid lubricating agent paste embedded in the hole or groove of the substrate. The metal substrate bears most of the load during the conflict.
After the conflict, the solid smoothing agent in the hole or groove is transported or reverse transported to the conflict surface, forming a smooth, outstanding, strong adhesion and evenly covered solid transport film on the conflict surface, greatly reducing the conflict wear. As the conflict progresses, the embedded solid smoothing agent is continuously supplied to the conflict surface, ensuring excellent smoothness for the conflict pair during long-term operation.
Three, water smooth bearing
Since the emergence of the oil resource crisis in the 1970s and people's attention to environmental protection in recent years, hydraulic transmission technology is facing severe challenges, and water-smooth bearings have gradually been promoted and applied.
Water-smooth bearings use water as the smooth and operating medium, which not only saves a lot of oil, but also prevents the pollution of the environment by traditional bearings that use oil as the smooth medium. Water has the advantages of non-polluting, wide-ranging origin, safety and flame-retardant properties, and is an aspirational smooth medium.
It can also reduce the key issues of conflict, wear, vibration, noise, and reactive power consumption. Therefore, the research on water-smooth bearings has important theoretical research and application value for improving mechanical efficiency and protecting the environment.