In general, the correct selection of bearing lubrication mode determines the service condition and life of triple gear pump bearing, so it is also a very important part in the design of gear pump. At present, the lubrication methods of three gear oil pump are as follows: high pressure oil leakage lubrication; high pressure oil supply to bearings continuously or pulse; high pressure oil supply to bearings pulse by reducing trapped oil volume; high pressure oil is directly introduced into bearing bore to realize high pressure lubrication; vacuum oil absorption and low pressure self-priming lubrication formed by expanding trapped oil volume; screw oil drainage Or oil suction type low pressure lubrication and the use of auxiliary pump oil supply for low pressure lubrication.

The former lubrication method is generally applied to rolling bearings and other lubrication methods with low requirements for oil cleanliness and low working oil temperature. The second to fourth lubrication methods use high-pressure oil for lubrication, which loses part of high-pressure oil and reduces the volumetric efficiency of gear oil pump. The last two lubrication methods, one of which reduces the bearing capacity of bearing surface, and the other is due to complex structure High cost but not adopted. Because of its simple structure, low manufacturing cost and high comprehensive performance, it is widely used in the lubrication of rolling and sliding bearings of triple gear oil pumps.

Using the vacuum oil absorption low pressure self-priming lubrication formed when the trapped oil volume is enlarged, there is a large oil passage outside the bearing connected with the low pressure area, so that the pressure outside the bearing is the same as that in the low pressure area. Due to the adoption of Du bearing, it is necessary to design a lubricating oil groove axially on the non bearing surface of the bearing inner hole, and form a lubricating oil groove by chamfering the inner hole of the side plate, so as to make the lubricating oil pass smoothly and keep the oil stable.