Design Of Three Stage Oil-free Scroll Brake Pump

The oil-free scroll compressors have been widely used due to their features of providing a clean,pollution-free gas source,and satisfying simple structure,light weight,and low noise.However,due to the high discharge temperature in the high pressure compression process of the oil-free scroll compressor,the excessive deformation of the scroll teeth at different positions is too large,which cannot be effectively applied to the high pressure brake pump.Therefore,this paper uses a project of company's oil-free scroll brake pump research and development as a background,to design a three stage oil-free scroll brake pump,that can provide a small displacement high pressure brake gas source for car brake device.The research work is as follows:1.In order to solve the problem of high discharge temperature caused by high pressure compression,comparing the advantages and disadvantages of one and two stage scroll brake pump design schemes,a new type of three stage oil-free scroll brake pump design scheme was proposed.2.Designing a new high pressure oil-fess scroll.This scroll can achieve the process of two stage gas compression on a single pair of scrolls,and a gas cooling process between the first and second stage of compression.According to the principle of equal pressure ratio distribution,a high pressure oil-free scroll profile was designed,and the high pressure oil-free scroll profile equation was determined.It is proved that this profile can achieve correct meshing and can effectively reduce the discharge temperature over 50% in the high pressure compression process.This scroll meets the design requirements of the scroll.3.To determine the gas temperature after cooling,theoretical analysis of the inter-stage cooing process of gas was performed.According to the principle of constant pressure cooling,a differential equation for the conservation of gas energy in the cooling process is established,and the cooling water correlation formula is deduced,which can prove that the cooling water of a given mass can achieve the constant pressure cooling of the gas.The scroll tooth correlation formula is deduced,which can improve the design of scroll.4.The parameters and structure design of three stage oil-free scroll brake pump.According to the technical parameters of the scroll brake pump,the parameters of the key components are analyzed and calculated,and combining the design and processing experience of the scroll compressor,the structure design Of the scroll brake pump is further implemented using SolidWorks software,thereby completing the design of overall machine.