At present, the needle roller bearings widely used in hydraulic gear pumps have many advantages: high load carrying capacity; small friction factor, low friction during starting and working, and relatively high mechanical efficiency; can be applied to both high and low speeds; can be applied to Larger temperature range; strong resistance to oil contamination.

But at the same time, there are many shortcomings: the noise is large, the overall size is large, and the overall structure is inconvenient; especially in the hydraulic gear pump, a long needle roller bearing is required, which causes the bearing performance to be more sensitive to the manufacturing and assembly accuracy, and the rolling Needle precision requirements are high, and the heat treatment process requirements are quite strict; the current type of wave needle bearings are non-standard parts, which require specific customization and high cost.

In recent years, with the gradual improvement and maturity of my country's DU bearing research and development and manufacturing technology, its load-bearing capacity and service life have been correspondingly increased, while the price has also fallen rapidly, and its application has become more and more extensive. Generally, the allowable specific pressure of DU bearings can be stabilized at 34MPa. If the structure is reasonable and enough lubrication is guaranteed, the allowable specific pressure can be stabilized at 44MPa, and the maximum specific pressure of the bearing can reach 58MPa.

The base of DU bearing is low-carbon cold-rolled steel plate, the middle layer is sintered spherical bronze powder, and the friction surface layer is rolled modified polytetrafluoroethylene. The wall thickness of the shaft sleeve is 0.7~2.5mm, and the thickness of the friction surface layer is 0.02-0.06mm. The steel back anticorrosion can choose tin plating and copper plating.

Bearings can work without lubrication, with low resistance, abrasion resistance, and longer life. The more they adapt to the specific and complex working conditions of gear oil pump bearings. The thin-walled structure has the advantages of compact structure, light weight and small volume, and makes the structure of the gear oil pump more reasonable and the structure design convenient. For example, the size of the gear journal can be increased to increase the overall strength and rigidity of the gear shaft.

The hydraulic gear pump adopts DU bearing to increase the rated pressure of the gear oil pump, reduce noise, increase impact resistance, and increase service life.