| Coal production and consumption in China account for nearly half of global power. The industrial gross of coal underground mining equipment is more than 100 billion(yuan), which is an important part of manufacturing in China. In recent years, with the rapid development of coal industry, its technical has achieved some breakthroughs, the technical level of partial products near or close to international advanced level, but because our country coal machine manufacturing development is on the basis of imitating foreign coal products, design theory foundation is weak, it is a larger gap in the comprehensive performance of product, reliability, degree of automation, the key components of products compared with foreign advanced coal enterprises, which has become the main obstacle restricting the development of coal industry in our country. Scraper conveyor is as one of the key equipment in coal mine underground mining equipment, to transport coal, and to provide walking tracks for coal cutter and to positon for hydraulic support, is a connection of fully mechanized equipment. The study of the stress distribution in the process of underground mining is the key to establish the power system of whole mechanized equipment. Therefore, this article will focus on analyzing the stress state of middle trough of scraper conveyor in the exploitation process and dynamic simulation calculation, at the same time, relying on the mining machinery and equipment research and development(experiment) project of national energy center, a complete set of mechanics test system of fully mechanized equipment, performance, simulation of coal wall will be studied, such as the construction of fully mechanized equipment test bench, for fully mechanized equipment provides a platform for theoretical research and test, to study and improve the coal product design theory in our country and to realize the coal products from manufacture to creation is of great significance.This thesis introduces simply the fully mechanized equipment of coal mine underground and movement situation, illustrates the interaction relationship among the scraper conveyor in the process of underground mining with the coal mining machine and the hydraulic support, analyzes in detail stress state when the cutting teeth is cutting coal, interaction force between the whole coal winning machine and scraper conveyor, establishes mechanics analysis model and calculation method between shearer roller and the whole;In the moving process of the scraper conveyor, the resistance of the coal pile are analyzed in detail on size and its changes and central slot situation given a hydraulic support thrust, points out at the beginning of push sneak the first middle trough and the second middle trough bearing the largest stress; Also the force situation of middle trough in drawing was analyzed, and points out that the convex concave port of middle trough in drawing bearing the largest stress; Finally, mechanical analysis software of the scraper conveyor will is wrote.For further force research of scraper conveyor in the pushing process, this paper by using the ADAMS software makes dynamic simulation of scraper conveyor advance process. By analyzing various factors in the real pushing process of scraper conveyor, to simplify the conveyer model, to calculate in detail coal resistance of a given central trough, the analysis of two conditions are put forward:(1) an pushing way with accelerated speed, namely given the pushing force and resistance to calculate;(2) constant speed condition, that is, a given pushing force and propulsion speed to compute. Simulation results show that when the final two pushing forces are similar, tension and bending moment of convex concave ends of central slot and dumbbell under accelerated condition are greater than under constant condition; The lateral force of dumbbell is much greater than the inside; dumbbell force; extrusion force of central slot is similar.For the experimental study on the mechanical system of coal mine mining equipment, this article relies on the center project undertook by Chinese coal mining machinery and equipment limited liability company of the national energy administration of mining machinery and equipment research and development(experiment), firstly fully mechanized working face testing center is built which completely simulate the coal winning machine equipment for underground mining, selecting MG500/1130- WD type coal winning machine, 15/28 ZY9000 / d type hydraulic support, SGZ1000/1050 type scraper conveyor and SZZ1000/400 transfer machine as experimental research equipment in order to carry on a complete research, and in the back of the hydraulic support equipped with an auxiliary oil cylinder, connected to the test bench rear, which is as fixed point of set equipment to guarantee the forward process with no back; Equipped with automatic mining system, equipment condition monitoring system and power supply system, mining automation and remote control can realize. Meantime for further simulating the coal mine mining environment, the coal from Datong area is adopted as the main aggregate, compounded with materials such as cement and water reducing agent, to build the coal winning machine face and plough face these two simulated coal wall. The coal mining machine working face of coal wall is divided into two segments, with hardness of f3 and f4, adopting layered casting method to simulate coal seam, so that the whole underground coal wall is close to the actual situation; The simulation coal wall is arranged with a total of 28 strain sensors by two layers and four rows to test mechanical changes of coal wall in the mining process.In this thesis, the smooth boots of coal winning machine tests are studied to analyze the force in the walking process and the pin rolls linking smooth boots to the whole will be transformed pin into pin shaft sensors, by testing two radial force of pin to calculate the acting force between smooth boots and scraper conveyor; by loading the different force to mark the pin shaft sensors; thicken smooth boots and slotting, data acquisition modules are installed on the smooth boots and acquisition data will be store and sent to the server through wireless signal. This paper collects the micro data of left and right sides from the end to the top return back of smooth boots(coal winning machine faces coal wall), respectively analyzes pressure and friction force for the two smooth boots for scraper conveyor. It is concluded that when the coal winning machine start up friction of smooth boots for scraper conveyor is biggest, points out that the static friction coefficient is about 2-2.5 times of the kinetic friction coefficient; Pressure range of right and left smooth boots for scraper conveyor is bigger, but the change direction is the opposite; Under no-load condition, the pressure of smooth boots for coal winning machine is stable, in the process of cutting coal, the coal winning machine is affected by the coal wall, so that the coal winning machine beating, the pressure of the single smooth boot for scraper conveyor is to zero; Also it obtains that in the course of cutting coal, the forward resistance of coal winning machine against the coal wall is far less than the friction force.This article also researches the force station of scraper conveyor dumbbell in the pushing process. By reforming two ends of dumbbell with adding four strain gauge respectively, strain output of strain gauge tests dumbbell force suffering, and the strain output of contralateral strain gauge(180 degrees arranged) calculate the bending moment suffered by dumbbell; Milling groove on the central slot, data acquisition modules of dumbbell are installed in the middle slots on the adjacent, and the collected data will be store and through the wireless signal is sent to the server. In the test a total of five dumbbells are reformed and tested, this article chooses a pair of dumbbells(goaf side and the coal wall side) for experiment and analysis, summarizes stress changes in the pushing process of the dumbbell on both sides, and be compared with the simulation calculation results, it is concluded that firstly the inside of the dumbbell of central trough suffers tension in the process, as forward pushing the stress of inside decreases to zero, and then stress of lateral dumbbell begins to gradually increase and gets the largest stress when it goes to the largest position, dumbbell in advancing process is bearing tension and bending moment at the same time.This article also has studied chain operation condition. Milling groove on the upper ring of chain, the strain gauges are welded on the tank for protection; Milling groove on scraper of chain connection, data acquisition module is installed on the scraper chain, and data will be collected for storage and sent via the wireless signal to the server. A total of eight chains for test, are marked and collects the micro strain single in the process of running; Through testing and analyzing the selected two chains, it illustrates that the stress of the link presents certain periodicity, and it is basically same to operation cycle; Under no-load condition, the stress gap of the up and down chains is not obvious; The largest stress of link occurs when it gets into chain wheel, and fluctuates most sharply.This thesis also studied the mechanic test scheme of coal mining machine guide sliding boots and the central trough of dumbbell. Transforming the Pin shaft connecting guide sliding boots and the fuselage to the pin shaft sensor is to test radial oriented force of sliding boots in the walking process, and tests the mechanical changes when the guide sliding boots installed with welding strain gauge is close to pin shaft parts, tests the axial force when guide sliding boots walking with installing tension sensors; Installing three welding strain gauge at each ear sides of the central slot tests stress of three directions on central slot under the thrust effect.This thesis also studied the data transmission and processing system, during the trial, the senso r will collect data and transmit to the data acquisition module through the data line, the data acquisition module adopts real-time wireless transmittal to the server and the local store in two ways to store data; And according to different data, during acquisition process, all of the data adopts unified time coordinate, which facilitates subsequent data processing and analysis.Through the research on actual operation condition of fully mechanized equipment for coal mine underground, a complete set of experimental platform of fully mechanized working face for coal mine is constructed firstly at home and abroad, and the parts of scraper conveyor and coal mining machine are studied for mechanic tests, it verifies platform’s feasibility and it is significant to promote our country theory level of the scraper conveyor and fully mechanized equipment of coal mine. |
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