Charac Terization And Analysis Of The Surface Micro-morpholo Gy On The Side Of Scroll Disk With Variable Cross-section

Scroll disk is the core part of the scroll compressor,and it is also the mo st prone to friction and wear.Under the influence of many factors,the micro-morphology of the side wall is closely related to the working performance of the scroll compressor,such as the life,wear resistance and even the running stability of the whole machine.With the gradual development of scroll disk from equal section profile to variable section profile,it is more and more difficult to process it.So it is necessary to evaluate the machining quality and precision by quantifying the surface micro-morpholo gy of scroll disk parts reasonably.Therefore,the research work on the characterization of the micro-morphology of the scroll disk side wall with variable cross-section is carried out in this thesis.The specific research contents include the following aspects:Firstly,based on the generating principle of variable cross-section scroll disk profile,the geometric model of three-segment base involute is established,and the reference model of variable cross-section scroll disk is established by using Pro/E software.On the basis of this,the scroll disk milling experiment is designed and completed.The surface morphology of the scroll disk with variable cross-section is measured by using Talysurf CLI 1000 surface topography measuring instrument,and the data of three-dimensional micro-morphology and surface roughness of the scroll disk are obtained.The data obtained were processed by MATLAB software,and the surface micro-topography was plotted,and the micro-morphology of the scroll disk with variable cross-section was evaluated qualitatively by co mbining with the surface roughness.Secondly,the limitation of the roughness parameter in the applic ation of morphology characterization is discussed,and the quantitative evaluation of the surface micro-morphology of the side wall surface of the variable-section scroll is carried out by means of the power spectral density evaluation method.Based on the two-dimensional power spectral density,the spatial frequency distribution of the surface micro-morpholo gy of the side wall surface of the variable-section scroll disk is analyzed systematically,and the directivity of the texture features of the side wall surface of the variable-section scroll is determined.And the roughness evaluation method is supplemented by the relation between the one-dimensional power spectral density and the roughness Sq.Finally,based on fractal theory,the three-dimensional morphology of the side wall of scroll disk with variable cross section is characterized.In order to further analyze the micro morphology of the side wall of the scroll disk with variable cross section,the fractal dimension is calculated by the projection covering method,and the accuracy of the method is verified by the experimental data of roughness.The results show that the fractal characteristic s of the side wall of the variable cro s s section scroll disk machined by hard aluminum 7075 and 45#steel are remarkable,and the fractal dimension is 2.4~2.8,in which the surface quality of the scroll disk of hard aluminum7075 is more complex than that of 45#steel scroll disk.On the basis of the traditional representation method,the micro-morphology of the side wall surface of the variable-section scroll is characterized by the method of power spectral density and the fractal theory,which can provide the basis for the system analysis and quantitative evaluation of the surface processing quality of the scroll.