Study on Wear Performance and Repair of Hydraulic Gear Pump

Hydraulic pump is the key component in hydraulic system, which plays the role of "heart". It provides certain pressure and flow of liquid to the actuator in hydraulic system, such as hydraulic motor or hydraulic cylinder, to ensure the normal operation of the actuator. The performance of hydraulic pump directly affects the reliability of hydraulic system.

Due to the influence of various factors, the working oil of hydraulic system is inevitably polluted by various kinds of pollution, such as solid particles, air, water, microorganisms, chemicals, radiation, static electricity, thermal energy and magnetism, among which solid particles pollution is the main pollution source. The existence of these pollutants seriously affects the performance, life and reliability of hydraulic systems and components.

According to statistics, the failure of hydraulic gear pump system is mostly caused by oil pollution.

Pollution wear analysis

There are a certain number of contaminated particles of different sizes and types in the hydraulic system. These particles are absorbed into the hydraulic pump with the hydraulic oil, and discharged with the high-pressure hydraulic oil. Because there is a certain gap between the moving mating surfaces of the hydraulic pump, the particles enter into the mating surface under the action of the pressure field and the velocity field. When these particles and the high-pressure hydraulic oil are discharged from the mating surface, the particles enter into the mating surface under the action of the pressure field and the velocity

After contact and relative movement of the surface of the mating surface, various wear conditions may occur, mainly fatigue wear, adhesion wear and abrasion wear.

Life assessment

The life of hydraulic pump refers to the working time before the internal parts of the pump are damaged or worn out and the pump loses its function. The life evaluation index of hydraulic pump mainly includes fatigue pitting corrosion (bearing life) (fatigue damage (fatigue life) of internal parts of pump.

The main performance of the pump is mechanical efficiency and volumetric efficiency. In actual use, the value of volumetric efficiency is relatively large, and the work of all components in the hydraulic system depends on the change of volumetric efficiency of the pump. The volume efficiency is taken as the main parameter of the pump, and the influence of the hardness, size, concentration, pressure and structure of the pollutants on the working performance and service life of the pump is evaluated according to the change of efficiency and its reduction degree.

Experiments show that the surface of gear pump with reduced volume efficiency can be improved by + 4 liquid, so that the volume efficiency of the pump can be restored to the normal range of the pump, and the reuse rate of the pump can be improved. This is a different mechanical repair method from the previous hydraulic pump. It does not dismantle the structure of the hydraulic pump itself, and reduces the pollution and sealing effect caused by dismantling and assembling. The application of this repairing method in hydraulic components has not been reported at home and abroad, and it is still in the stage of experimental research. However, because the + 4 liquid itself belongs to nano-material solution and its price is relatively expensive, further research and development are needed to reduce its use cost. Only in this way can it be popularized and applied.