Water-suspension bearings are traditionally called water-lubricated bearings.  Water-lubricated bearings are one of two classic types of liquid-lubricated sliding bearings (friction pairs).  Compared with oil-lubricated bearings, water-lubricated friction pairs have the following characteristics: ●Low cost-replacing oil with water as a lubricating medium, low cost.  ●Environmental protection and sanitation-there is no harm to the environment and human health, and it is good for environmental protection.  ●Good safety-water will not burn, and it can maintain longer working stability.  ●Easy maintenance-water itself has a cleaning function, so the maintenance of the friction pair system with water as the medium is very convenient.  The water suspension bearing material is one of natural water or water-based liquid, and the other is non-metallic materials. It also uses a small amount of metal materials. It has energy saving, emission reduction, vibration reduction, noise reduction, safety, reliability, wear resistance, high efficiency, long life and  It has the advantages of no pollution and can be widely used in important equipment or field transmission systems such as ships, oceans, machinery, mining, metallurgy, national defense and military industry.  Water-lubricated plastic or rubber bearings have been widely used in the shipbuilding industry, and water- or water-based liquid-lubricated ceramic bearings and hydrostatic water-lubricated rail bearings have gradually begun to be used.  Commonly used materials for water-lubricated bearing bushings include metal materials, iron pear wood, bakelite with cloth, plywood, engineering plastics, ceramics, rubber, and rubber alloys.  The performance of water-lubricated bearings of different materials varies greatly.  1. Metal material The significant advantage of metal material is its large carrying capacity, but its disadvantages are that it is not resistant to impact, has poor vibration damping effect and is prone to electrical corrosion.  2. Tilapia Tilapia is dense and hard with high relative density.  Iron pear wood contains a high proportion of resin, resin essence, a very small amount of hard resin and bitter essence.  Because it emulsifies in water and has a self-lubricating effect, it is widely used in ship stern tube bearings.  The disadvantage is that it is not suitable for waters with a lot of sediment, and the volume expands after absorbing water.  Iron pear wood is a non-renewable resource and is a consumable product. Due to the lack of resources, it is expensive.  3. The resin content of cloth bakelite is higher, and the abrasion resistance is better.  The structure of the striped bakelite bearing bush of the stern bearing is the same as that of the iron pear bush, and it is not suitable for waters with a lot of sand.  4. Glued laminates Glued laminates are impregnated with artificial resin, and phenolic resin binder is used. The commonly used wood is birch.  The layered wood plastic forms a friction pair with steel or bronze, and has good wear resistance when lubricated by water (the same is true for oil lubrication).  The main disadvantages are poor thermal conductivity and easy expansion when absorbing water, even if it is moisture in the air (hygroscopicity) or dripping water (water-absorbing).  The swelling of the material will change the size of the finished product and affect the operation of the bearing.  5. Engineering plastics Phenolic resin and fluorinated vinyl resin are the most common engineering plastics used to make water-lubricated bearings.  Plastic has good affinity to water and has excellent lubricating properties; the high hardness of plastic can withstand larger loads.  But its disadvantage is that it expands greatly after absorbing water, which reduces the bearing clearance, cannot adapt to the deformation of the shafting, and is prone to shaft holding or burning.  6. Ceramic ceramics have the characteristics of high temperature resistance, wear resistance and corrosion resistance, strong adaptability to impurities and large carrying capacity, and are being widely concerned and applied.  As a porous material, it also has a certain degree of self-lubricity, but the disadvantage is that it has poor impact resistance.  7. The biggest feature of rubber and rubber alloy rubber bushings is that they have strong cushioning and shock absorption properties; good hydrophilicity, low coefficient of friction in water and wear resistance; small modulus of elasticity, adapt to the inclination or bending deformation of the shafting  , High reliability.  The disadvantage is that the coefficient of dry friction is large and it is easy to sinter.  Since the late 1980s, the former Soviet Union has conducted in-depth research on the characteristics and materials of hydrostatic bearings and hydrodynamic bearings using water as lubricating fluid.  The United States, Britain, Germany, Japan and other countries have subsequently done a lot of research work on water-lubricated bearings.  Since the mid-1950s, water-lubricated bearings have been used in marine centrifugal pumps and axial flow pumps in China, and theoretical exploration and experimental research work began in the early 1960s.  Such as the water-lubricated bearings of nuclear pumps, the phenolic anhydride plastic water-lubricated bearings used on the large vertical axial flow pumps of Jiangdu No. 3 Station, and the water-lubricated plastic thrust bearings used on the submersible electric pumps.  However, most of them are designed and manufactured by importing technology from abroad and summing up empirical parameters through model tests, comparison and evaluation tests.  Considering petroleum resources and environmental protection, there is a growing interest in water and water-based fluids instead of mineral oil as the working medium of mechanical transmission.  my country’s goal of becoming a maritime power has led to the rapid development of marine engineering equipment. It has put forward a stronger and more urgent demand for high-end water-lubricated bearing products, and has put forward more and more demands on the performance of water-lubricated bearings such as vibration, noise, reliability, carrying capacity and life. The more demanding technical requirements