Axial Piston Pump/motor Magnetic Slipper Pair Structural Design And Characteristics Research

The slipper pair is one of the three major friction pairs of axial piston pump/motor,many experts and scholars have shown that the failure model of axial piston pump/motor is mainly wear failure of friction pair,especially,the wear failure of the slipper pair.Regarding the design method of axial piston pump/motor slipper pair as the carrier,the dissertation submitted a new kind of magnetic slipper pairs whose hydraulic pressure balances the electromagnetic force.On this basis,the basic structure of the magnetic slipper pair was designed,and the electromagnetic characteristics and oil film characteristics of the 'magnetic shoe were studied emphatically.The research results laid the foundation for the practical application of the magnetic slipper pair.The following conclusions are drawn from the analysis of its structure and characteristics:(1)In this paper,the structure of magnetic slipper pair was put forward,and the working principle and the selection of magnetic slipper pair structural parameters were introduced.The mathematical and finite element models were established.The effects of voltage,electric field intensity,magnetic field and magnetic induction intensity on the performance and service life of the magnetic slipper pair were analyzed.The research results are as follows:the position of maximum electric field strength is shown on the place where iron core and swashplate contacts in the structure of the magnetic slipper pair,the air gap where iron core and swash contacts will have a discharge phenomenon which can accelerate the ageing of the materials,and then affect the service life.The main magnetic circuit of the magnetic field can form a closed circuit,the magnetic leakage phenomenon is less,and there is no superposition and interference in the magnetic field distribution between the field winding coils.The more the field winding coil turns,the greater the electromagnetic force,when the current is different,the peak of the magnetic induction intensity appears near the top of the field winding coil,when the peak is reached,then the magnetic induction intensity is minimized at the bottom of the field winding coil.(2)According to the mathematical model of the magnetic slipper pair,the formula of electromagnetic force of slipper pair was deduced and its correctness was proved.In the study of oil film characteristics,the influence of the factors such as the speed of the slipper,the load and the magnitude of the electromagnetic force on the oil film thickness of the magnetic slipper pair was analyzed.The research results are as follows:when the balance of the hot wedge and the remaining compaction force,the effect of the load on the electromagnetic force is greater than the influence of the slipper speed on the electromagnetic force.The film thickness changes with the change of the rotation angle of the slipper.The change of the slipper speed has little influence on the oil film thickness.The thickness of the oil film reaches the maximum when the angle of the slipper goes to 270 degrees,then the oil film thickness decreases gradually.In order to be convenient and flexible in adjusting the thickness of the slipper pairs oil film and reduce slipper pairs failure due to the wear and tear.Based on the analysis of the change of the oil film during the whole movement of the axial piston pump/motor magnetic slipper pair,the test bench of the axial piston pump/motor magnetic slipper pair was designed.