Research On Characteristic Modeling And On-line Monitoring Technology Of Automobile Turbocharger Bushing Machine

The turbocharger plays an important role in enhancing the engine power and driving performance of oil-powered vehicles.The valve core hole bushing of turbocharger is an important component of turbocharger,and its assembly is completed through interference fitting.The quality of interference assembly has a direct impact on the use and safety performance of automobiles.At present,due to the lack of guidance from the theory of pressuring characteristics,the pressuring operation of the valve core hole bushing in turbocharger often leads to misscrapped,which leads to the increase of production cost.Moreover,the quality monitoring technology of pressuring machine is not perfect,and too much dependence on manual detection,so it is difficult to realize the automatic online monitoring of precision pressuring and pressuring quality.In view of the above problems,this paper takes a certain type of automobile turbocharger bypass valve valve core hole bushing press-mounting as an example to study the press-mounting characteristics modeling and on-line monitoring technology of press-mounting quality.Specific research contents are as follows:(1)This paper discusses the significance of precision pressing of turbocharger bushings,compares the characteristics of two traditional driving modes of bushings pressing machine,namely hydraulic drive and pneumatic drive,discusses the important application of servo precision drive in high performance precision pressing machine,and introduces the structural characteristics of some key units of pressing machine for engineering application.It provides an important reference for the performance improvement of pressing machine and the design of a new generation of precision pressing machine.(2)Based on the thick-walled cylinder theory,the mechanism of the pressing force is analyzed.The results show that the interference between the mating surfaces,the friction coefficient and the length of the pressing surface are the main factors affecting the pressing force.The finite element numerical simulation software was used to establish the mechanical model of interference fit for the spool hole bushing and carry out the numerical simulation analysis.The comparison between the numerical simulation and the actual pressure fitting curves was made to verify the accuracy of the model.Controlled by a single variable method,in view of the different design parameters for turbine casing and liner pressure into the force and the surface of interference fit between the influence degree of the stress,as well as the different stages of being connected in the turbine shell and liner surface analysis of numerical simulation of the maximum equivalent stress distribution,and the research conclusion for field operation and installation guide subsequent installation quality on-line monitoring system for development.(3)The dynamic model and the Simulink numerical simulation model of the pressing process were established,and the pressing force of the interference fit was described by the nonlinear friction equation.Further,the numerical simulation of the pressing process was carried out,and the curve of the pressing process obtained showed obvious stick-slip motion characteristics.The simulation results show that the servo control strategy and algorithm can achieve better dynamic characteristics of the system,which provides an important reference for improving the quality of pressing assembly and production stability.(4)An on-line monitoring technology of bushing press-mounting quality,which includes pressure monitoring,vision monitoring and laser height detection,is proposed.The collection scheme of key press-mounting data is designed.By means of field experiments and off-line analysis methods,the different effects of least square fitting algorithm,amplitude limiting filter algorithm and moving average filter algorithm in the processing of abnormal data are discussed.With PLC as the bottom controller and industrial computer as the upper controller,an online monitoring system for the pressure mounting quality of turbocharger bushings is developed.The long-term field operation and some sample experiments show that the developed system has the advantages of high detection accuracy,stable operation and high production efficiency,which verifies the rationality and effectiveness of the design of on-line monitoring system for pressing assembly quality.