Research On Static Pressure Bearing Seal Of Hydraulic Cylinder And Its Low Friction Characteristics

As one of the main actuators of a hydraulic system,modern hydraulic cylinders have the characteristics of high transmission performance,stable operation,large load capacity,fast response frequency,small frictional resistance and fast running speed.Most traditional hydraulic cylinders are sealed with a seal ring.The piston rod(piston)is in direct contact with the seal ring.When the piston rod of the hydraulic cylinder is subjected to a large radial load,the seal will be damaged.The sealing performance of the hydraulic cylinder will be deteriorated,which will make the control accuracy of the hydraulic cylinder and the smooth running is affected.The hydrostatic pressure technology uses low friction resistance,high transmission efficiency,stable operation,strong anti-load capacity,high support stiffness and good seismic performance.It is applied to hydraulic cylinders to achieve low friction static pressure sealing.This paper studies the static pressure support structure and oil film characteristics of hydraulic cylinders.The main work is as follows:First,design the static pressure support structure of the guide sleeve and the piston,and analyze the static pressure oil supply system.Based on the principles of fluid mechanics and frictional lubrication,the bearing principle of the hydrostatic structure is analyzed,and a three-dimensional model of the oil film is established.The mathematical model of the bearing capacity,stiffness,temperature rise,and leakage of the oil film is theoretically derived,and the lubrication performance of the hydrostatic support oil film is analyzed.Secondly,the three-dimensional oil film model is meshed,the UDF program is used to write the piston rod motion equation,the viscosity-temperature relationship of No.46 hydraulic oil is imported into the software,and Fluent simulation software is used to simulate the sealing performance of the oil film under different working conditions.The relationship between the oil film at different inlet flow rates,different oil film thicknesses,different moving speeds of the piston rod,and different reciprocating frequencies and the bearing capacity of the hydrostatic bearing oil film,oil film temperature rise,and leakage were analyzed.Finally,a static pressure support hydraulic cylinder experimental bench is set up to conduct an experimental analysis of the radial displacement of the piston rod.An eddy current sensor is used to measure the radial displacement distance of the piston rod at the maximum stroke,and the bearing capacity of the static pressure guide sleeve is analyzed.The temperature of the oil chamber of the guide bush at different speeds and different reciprocating frequencies is analyzed experimentally.The maximum temperature of the oil chamber of the guide bush is measured with a temperature sensor to determine the location of the highest temperature.By studying the sealing performance of the oil film of the hydrostatic support part of the hydraulic cylinder,a mathematical model of the hydraulic cylinder guide sleeve and the piston hydrostatic support structure is established,and the antieccentricity characteristics of the hydrostatic support and the oil chamber temperature are analyzed to improve the hydrostatic pressure.The lubrication performance of the supporting hydraulic cylinder provides a theoretical reference.