Geometric Error Evaluation And Selective Assembly For Scroll Compressor

Scroll compressor is a kind of positive displacement comressor,with high efficiency,high reliability,low power consumption,low noise,few parts,compact structure and many other advantages.Scroll compressor has broad market prospects and development space in the refrigeration and air conditioning,power engineering,transportation and other fields.In this paper,the scroll compressor is studied from the perspective of critical geometric error assessment and selection of assembly.The main goal of the paper is to achieve effective improvement of the assembly stage of the scroll compressor,to improve the stability of the assembly and to enhance the product once the assembly success rate.The main contents of the dissertation are as follows:(1)Based on the research background of the paper,the research situation of the scroll compressor is summarized,and research status at home and abroad of geometric tolerance,profile and position error assessment,selective assembly are analyzed.(2)The basic terminology,geometric tolerance principle and related requirements of geometric tolerances are expounded.The method of establishing the reference fitting and the reference coordinate system is proposed.Then,the basic working principle of the scroll compressor is described,and the assembling characteristics of the scroll compressor and the key geometric tolerances affecting the assembly are analyzed emphatically.(3)The profile error assessment method of scroll-plates is studied.The error evaluation of free surface profile is a difficulty in precision measurement.The unified mathematical model for evaluating surface contour errors is created with the theory of point set topology.On this basis,combining with the characteristics of scroll type line,profile error evaluation algorithm for the scroll plate is established.Carl Zeiss UMC550 is used in the experiment,the data from the UMC550 is applied to the proposed algorithm,the result compares to calculation value of UMC550,and it shows the two results are basically identical.The precision of the proposed algorithm reached the level of the included software algorithm in UMC550,and also the proposed algorithm has higher application value for self-developed measurement software of scroll compressor.(4)The evaluation of the position error of the vortex plate hole group based on the minimum area is studied.As a precision mechanical products,scroll compressor made a higher demand on its parts manufacturing,positions of fixed plate and rack are one of the key indicators.In this paper,the key hole group of fixed scroll plate is analyzed.Secondly,according to the definition,the position error is transformed into the distance between the discrete point and the ideal axis,then the position error evaluation model of the hole group is established,rapid calculation and evaluation of the position error achieved Further.The calculation of the example shows that the method of evaluating the position error of fixed scroll plate is effective and has good reference value for practical application.(5)Aiming at the scroll plates of the scroll compressor,the assembly of the parts involves a number of quality parameters,and a method of selective assembling the scroll fixed plate under the multi-quality factor is proposed.Scroll plates are the key parts of the scroll compressor,and the assembly of the scroll plates is critical and difficult to the whole assembly of the machine,which involves a number of quality parameters.Firstly,the assembly characteristics of scroll plates has analyzed,in order to reduce the impact of fluctuations on assembly quality,a multi-objective integrated evaluation function for the minimum of radial and axial clearance and minimum mismatch rate is established,which used the variance model.Then,Computer aided selective assembly method based on genetic algorithm was designed.The experimental results were compared with the Complete Exchange Method,it shows that the proposed method can solve the problem of scroll plates assembly with multiple quality characteristic,which means that it can optimized both the radial clearance and the axial clearance,and minimized the surplus components in the meanwhile.(6)The prototype system for scroll compressor critical geometric error assessment and selective assembly was designed autonomously and quickly,Relying on PHP and MySQL.The development environment of the system is introduced,and the user interface is designed.The key geometric error assessment module and the selective assembly module are developed.Finally,the paper summarizes the full text and provides a prospect for further work.