Research On The Design Key Technologies Of Large Mining Excavator

Nowadays in China, as there is numbers of large-scale opencast mines being built or planned,gradually being constructed and goes into production, the demands of large mining excavators areever rising which serves as crucial equipment in exploiting mines. Large mining excavator is a kindof important technical equipment, representing the national level of equipment manufacturingindustry for its performance closely relates to the construction and production of large-scaleopencast mine. Comprehensive researches of its designing theory, technique and methodsbecome significant and meaningful for our national energy security, resource safety and enhancingthe overall international competency of mining machinery equipment.This article refers to theprogram “Development of75m3Large-scale opencast mining excavator”, branch of a national “863Program”-Large-scale Opencast Mining Technology and Equipment and goes further in research ofthe key technique of large-scale mining excavator. After serious discussion of the design theoryand method of it, we come out with a theoretical guiding principle of its design. We also study onthe working unit and walking unit of large-scale mining excavator and build up digital prototype of it.Based on DEM (discrete element method), research on scoop design of mining excavator isongoing and a digital design platform of mining excavator is set up. The main research contentsare as follows:Based on literature research, a review is built up of large mining excavator’s working principleand its developing situation domestically and internationally. A summary of key techniques indeveloping mining excavator and the process of excavating working principle is completed. After adetailed analysis of research situation of working unit, walking unit and scoop design, finally wecome to an analytical result about the research of digital design platform.We study on the designing theory and method of large mining excavator. Regarding thecurrent situation that almost all researches about large mining excavator are focused on a certainpart structure, we make a deep research on the overall design theory and method of large miningexcavator. As for the large mining excavator which are significant equipment production but areproduced in single piece or small batch, they are specifically analyzed for their innate designingcharacteristic. Accordingly, following the synthetic designing method, design of excavator productsare divided into three steps, namely planning, designing and examining. Also, the design processinvolves seven contents: design principle, design environment, design process, design target,design content, design method and quality examination as well as evaluation. Moreover, carefulresearch analysis of every part is expected, thus it can provide a theoretical guidance for furtherdesign of large mining excavator.Research has been done of working unit design of large mining excavator. On the base ofanalyzing structure and composition of working unit of large mining excavators, we studied itsmechanism principle, analyzed in detail its excavatoring locus equation and moving vector relation.Virtual prototype of the working unit has be built up based on the theory of multi-body dynamics.Then study of the prototype has been accomplished. Dynamic simulation and analysis of key partsout of working unit has been processed with the application of Rigid-Flexible Coupling Theory. Digital prototypes have been set up, with bucket arm as flexible body and with boom as flexiblebody separately. Then with the simulation results of dynamic stress, advanced method andthoughts could be provided for detailed design of working unit.Research has been done of walking unit design of large mining excavator. Work has mainlybeen done like setting up the rigid-flexible coupling digital prototype of crawler travel unit andanalyzing crucial parts, for example, track plate and support wheel. Simulation and analysis areespecially carried out on grade climbing conditions, including the changing discipline of forcesbetween track plate and the ground, of meshing forces between track plate and driving wheel andof the loading of9support wheels as well as the guiding wheel. In the crawler travel unit which isbuilt by rigid-flexible coupling simulation, the crawler frame is taken as a flexible body, which can beused in the study of changing discipline about dynamic stress and strain when in the workingcondition of straight running.Theoretical analysis and study of scoop design in mining excavator has been carried out. Weoptimize the scoop capacity and analyze theoretically how to determine the excavatoringresistance. Process simulation of scoop excavatoring has been done with the help of discreteelement method. Analysis of scoop’s dynamic response and materials flow has been accomplishedregarding situation of different excavatoring stuff. The information collection of scoop forces andfilling stuff could provide theoretical foundation for scoop optimization. Finally experimentaloptimizing design of scoop has been successfully accomplished.Invention and development of digital design platform of large mining excavator has been done.After accurately orientation of the platform demands, the platform framework structure is designed.On the basis of NX technical platform of CAD/CAE/CAM, database technique is adopted forbuilding engineering database. Combining3D parametric template technique and FEM templatetechnique, mining excavator digital design platform which satisfy the real application has beeninitially set up. The function of the platform is more focused on the real engineering application,owning the characteristic of standard and ordered working process, convenient operation, whichcan impressively enhance the efficiency of series products design.