Contact Dynamics Analysis For Sprocket And Round-link Chain Of Scraper Conveyor

Scraper Conveyor is the most important conveying equipment in underground working area of coal mine,with Shearer and Hydraulic support,it makes mechanization production system used for coal mining,carrying and support. The technique level of Scraper Conveyor has a direct impact on the level of modernization of comprehensive mechanized coal mining equipments,the short life of sprocket is one of main facts which limit the development of scraper conveyor to high power and high efficiency.With the application of new materials and the improvement of the process technology, from the view of the traditional experiment can not be achieved,applying modern design theory and method,revealing the internal contact mechanism between sprocket and round-link chain and optimizing the structure of sprocket have been the hot research topic.Aiming at the traditional test methods are long in operation time and high in cost to obtain load parameters of Scraper Conveyor,the paper apply MSC.ADAMS to build the equivalent dynamics model of sprocket transmission system. The dynamic characteristics of this system are simulated under the Rev. Braking process, stable operation process, chain blocked and chain scission. The distributions and rules of driving torque and it’s resultant moment of motor at scraper head and tail, the contact force response between chain and Sprocket, the chain tension response are discussed, which provides reference for statics analysis and transient dynamic analysis of sprocket transmission system,at the same time,it can provide reference for optimizing the structure of sprocket.Aiming at the traditional design methods can not fully consider the dynamic effects of scraper conveyor in the actual operation process, the paper apply MSC.DYTRAN to build and analyze the sprocket transmission system under the Rev. Braking process, stable operation process, chain blocked.The strain,normal force and shear force responses are discussed. Chain blocked condition is emphatically discussed, the interaction process between sprocket and round-link chain is recovered.The statics finite element analysis of sprocket transmission system under stable operation process and chain blocked were analyzed by MSC.MARC,the stress,strain,displacement response of sprocket and round-link chain were discussed. Based on modifying the envelope surface and centre line of the distorted chain, the paper proposed two methods to optimize the structure of sprocket, to wit, drawing out the modifying the envelope surface of the distorted chain to generate the sprocket nest surface or drawing out the centre line of the distorted chain as the track, the standard circular as the section, to generat the sprocket nest surface.The structure of sprocket was optimized based on these basis, the analysis result shows that the mechanical behavior of optimized sprocket is improved greatly.Two optimization methods are investigated, whereas the method based on the envelope surface of the distorted chain is proposed in engineering applications.