Design And Performance Analysis Of An Oil-air Lubrication System

Compared with the traditional grease lubrication, oil lubrication and fog lubrication, oil-air lubrication has many advantages, such as high efficiency, green and energy conservation, etc. In recent years, this kind of lubrication technology is applied more and more widely in our country. Therefore, there is significant of researching the theory of oil-air lubrication and development of a new type of model for a wider application.Based on the researches of oil-air lubrication technology and the theory analytical methods of traditional hydraulic system and components, virtual prototype, a physical model, of an oil-air lubrication system is designed by Solidworks, and then mathematical models of the system and its key components are built by AMEsim, and finally researches for the factors which influent on working performances of the system and its key components are quantitatively done in this thesis. The main researches and conclusions are as follows,(1) A new type of oil-air lubrication system is designed based on the theory and the working requirements of the oil-air lubrication system. The main work includes design for schematic diagram of the system, setting of working parameters, performances analysis, selections of components, and design for virtual prototype of the system.(2) The mathematical model for progressive distributor, one of the key components of the oil-air lubrication system, is established, and then the performance of it is analyzed. The overlapping motion is the main reason, which leads to the fluctuation of the flow and the pressure of the system. The reasonable viscous friction coefficient is benefit to stability of the system, as the piston motion becomes lag, the flow of the outlet decreases, and the working time of the oil outlet increases with the increase of the viscous friction coefficient. The influence of the size of throttle orifice on the flow of the outlet is analyzed, as the flow of the system increases, the instability of the flow and the pressure also increase, the oil-outlet frequency of the progressive distributor increases, and the instability of the outlet flow of the progressive distributor increases, while the size of the throttle orifice increases. When the size reaches to a certain value, the flow of the system keeps to a certain value with bigger fluctuation around it, the oil-outlet frequency of the progressive distributor keeps to a certain value, but the flow of oil-outlet fluctuates obviously. (3) The mathematical model for proportional throttle valve, another key component of the oil-air lubrication system, is established, and then the performance of it is analyzed. The structure parameters are determined for the proportional throttle valve while it has a small flow, and the diameter and the maximum displacement of the valve core is given out. The hydraulic power of the small flow proportional throttle valve is calculated, the dynamic characteristics of the proportional throttle valve is influenced largely by the hydraulic power while the throttle valve has a small flow and instability of the hydraulic power will make the nonlinear for the input signal of proportional throttle valve in a small open. The influence of the damping aperture to the dynamic characteristics of the proportional throttle valve is researched, and a reasonable damping aperture is shown out. The influence of the viscous friction coefficient to the dynamic characteristics is studied, the system response frequency decreases with the viscous friction coefficient increases, so the valve core displacement and the system flow are influenced.(4) The mathematical model for the system is established, and the performance of it is analyzed. The dynamic characteristics of the oil system are analyzed, the control strategy of single and double pumps is determined; the influences of the oil supply frequency and the pressure in lubrication chamber on oil flow and pressure of the system are researched. The relation curve of the air flow in pneumatic throttling valve and oil-air mixing pipe is given, and the influence of the pressure in lubrication chamber on the air flow and the air pressure is analyzed.All these research contents and conclusions will do supports to design and manufacture the oil-air lubrication in the near future.