Study On Lubrication Characteristics Of High-speed Gear Pump Sliding Bearing

External gear pump which has certain self-absorption capability,high reliability and long service life is simple and compact in structure,small in volume and light in weight,insensitive to oil pollution.In addition,it has obvious advantages of axial clearance compensation,unloading groove and radial unbalanced force balance structure,low operation and maintenance cost,which is also widely applied to harsh environmental conditions such as engineering machinery,aerospace,and the like.Increasing working pressure of the gear pump is one of its development directions and it causes many problems :(1)the bearing life is greatly shortened.(2)pump leakage intensifies and volumetric efficiency decreases.In this paper,the external gear pump is taken as the research object,it aims at improving the bearing capacity and service life,establishing the system simulation model of the sliding bearing of the external gear pump,analyzing the diversion effect of transverse groove,circumferential groove and spiral groove on cold and hot oil and reduce the temperature rise of the bearing and studying the formation mechanism of the long-term overheating phenomenon of the sliding bearing in high-speed precision machinery.In this paper,the characteristics of different groove-type hydrostatic sliding bearings for gear pumps are numerically analyzed:(1)According to the structural characteristics of fluid dynamic and static sliding bearings with different groove types,the transformation in rectangular coordinate system and oblique coordinate system and Reynolds equation of bearings in oblique coordinate system are deduced.(2)Calculate the radial stress of gear pump and check the bearing capacity of sliding bearing.(3)The oil film thickness equation,bearing capacity and temperature Reynolds equation of fluid dynamic and static sliding bearing with transverse groove,circumferential groove and spiral groove are derived respectively.(4)Using Matlab to draw relevant graphs,the dynamic and static characteristics of fluid dynamic and static pressure sliding bearings with different groove types are compared and analyzed.Considering the influence of groove type width,number,depth and eccentricity on bearing performance,many valuable conclusions are drawn.(5)The mathematical model under laminar turbulent flow is established,and thestatic characteristic parameters of spiral groove bearings under laminar turbulent flow are analyzed.Research shows that fluid dynamic and static pressure sliding bearings with different groove types have certain flow guiding effect on oil,thus avoiding repeated heating of lubricating oil.At the same time,the width,number,depth and eccentricity of groove have different effects on oil film pressure,friction resistance,end leakage and temperature rise.Helix angle can guide the flow of oil to a certain extent and can obviously reduce the temperature rise of oil.