Investigetion On Oil Film Temperature Characteristics Of Port Pair Of Axial Piston Pump

During the operation of axial piston pump,the clearance of oil film in port pair plays the role of sealing and bearing,and also produces a large number of leakage and friction power loss.In order to design axial piston pump with reliable performance,long service life and high efficiency,it is necessary to establish an effective model of oil film pressure distribution,oil film bearing capacity,leakage flow,power loss and temperature.Then,to clarify the physical phenomena inside oil film of port pair is very importment to guide the design of port pair and improve the comprehensive performance of piston pump.Aiming at wedge-shaped oil film in port pair of axial piston pump,this paper established a theoretical temperature model of oil film in port pair based on heat flow coupling,analyzed and discussed the influence laws of working pressure,rotating speed and wedge angle on oil film temperature characteristics of port pair,and established oil film temperature test-bed for experimental verification.The main works of this paper were as follows:(1)The axial force equilibrium model of port pair was established,considering the support force generated by mixed friction contact,dynamic effect and thermal wedge effect of clearance oil film in port pair;Based wedge angle,azimuth angle and minimum oil film thickness,an oil film thickness model of port pair was established;The theoretical model of clearance oil film temperature in port pair was established,and the influence of surface morphology of port pair on oil film viscous friction loss and heat conduction on oil film temperature were considered;Combined with viscosity temperature characteristics of hydraulic oil,the heat-flow coupling calculation of oil film temperature of port pair was carried out.(2)The effects of working pressure,rotating speed and wedge angle on the oil film temperature of port pair were analyzed.The results showed that the maximum oil film temperature and overall temperature increased with working pressure and rotating speed.The maximum oil film temperature point of port pair coincided with the minimum oil film thickness point,and the temperature rise rate at maximum temperature point was large.In the area from-8 ° to 8 °near the maximum temperature point of oil film,oil film temperature increased with wedge angle,and decreased with the increase of wedge angle in other areas.As working pressure,rotating speed and wedge angle increased,there was a“steep” temperature change in the area around the minimum oil film thickness point,and wedge angle was the main factor affecting the regional distribution.(3)The oil film temperature test-bed of port pair was built,a test method of oil film temperature of port pair was proposed,and the highest temperature point variation law of oil film in port pair was analyzed.The results showed that when working pressure was constant,rotating speed changes,the position of the highest temperature point of oil film in port pair remained unchanged,and its value changed;When rotating speed was constant,working pressure changed,the maximum oil film temperature changed,and its position moved to the top dead center.Through the comparative analysis of theoretical calculation and experimental results,it was verified that the theoretical model could accurately predict the maximum oil film temperature and overall oil film temperature distribution trend.