Structure Dynamic Characteristics Research Of Cutting Part Of EBH300A Roadheader In Coal Mine

The EBH300 A transverse axis roadheader a coal mine tunnel coal petrography roadheader, which is designed by the Shijiazhuang coal mining machinery co., LTD. It is one of the two task of the “the key technology of the remote control of underground coal mine cutting equipment”( Project number: 2008AA062201) of the 863 national plan technical project, which is unite assumed by China university of mining and technology(Beijing), China Coal Energy Company Limited and Jizhong Energy.The transverse axis roadheader is the main equipment of the road way tunneling of long arm working face exploit, which has two types: the vertical axis type and horizontal axis type. To some extent, the transverse axis roadheader is different from the shield roadheader which is used in the massif and underground traffic tunnel exploit. The shield roadheader use the multiple disk type cutter to cut the rock soil tunnel, which has the ability of cutting the hard rock, such as the Large scale tunnel shield roadheader which is used in the traversing of the alpine in Europe, and the transverse axis roadheader use the rotate roller which has the cutting pick fix on to cut the coal rock or the half coal rock, which is used in the tunneling of the coal roadway or the soft rock road way’s drifting. For the complex varying geological conditions is naturally format, roadheader always face the hard rock in the coal tunneling or the soft rock tunneling, so the roadheader may meet with the impulse load of the hard rock cutting, the strength and abrasive resistance of the cutting pick and the shock vibration resistance performance of the cutting part are very important, so they become the hot spot and the key technical in the exploration of the roadheader. At present, the exploration of the shield tunneling machine of the underground coal mine tunnel is underway, however, the tunnel in the underground coal mine is narrow and zigzag, the large equipments are not suit, and the shield tunneling machine which has a smaller volume and mass can not bear the shock vibration of the hard rock cutting. The transverse axis roadheader will be the main equipment in the tunneling of the underground coal mine, which is irreplaceable, and the blast and muck loading are the only choice of the hard rock tunneling.Aimed at the hot point and the key technical of the transverse axis roadheader exploration, the dynamic property of the structure of the cutting part of the EBH300 A type transverse axis roadheader is deeply explored in this article. During the tunneling of the roadheader, the position and attitude of the cutting part varying continuously, so the cutting head can have the continuous motion in the space and getting the tunnel cross section. The attitude and position of the hole machine changes with the varying of the attitude and position of the cutting part, so the stress state and the dynamics property of the cutting part and heading machine changes greatly during the working process, which has a direct influence on the ability and efficiency of the cutting. In this article, the attitude and position, the kinematic character, the dynamic property of the heading machine and cutting part are explored, which reveals the rule of the structure motion and the mode of vibration during the working of the cutting part of the roadheader. These explorations offer the basis for the optimum structural design, the bearing capacity enhancing, condition monitoring and more excellent performance heading’s exploit.The works of this paper are:Combined with the characteristics of scientific research and engineering problems, in order to slove the problem of the roadheader cutting part in the underground rock excavation work of coal mine, through the finite element dynamic analysis of the roadheader cutting part, the engineering technical problems of the roadheader cutting part are summarized as scientific researches on accurate quantitative.(2)Combined with the theory of the roadheader cutting part and the actual working conditions of the roadheader cutting part’s application conforms the actual production of coal mine. Combined with theoretical analysis, numerical calculation and engineering production practice of the roadheader cutting part makes the research results more close to the actual project.Based on the mine roadheader research results, the theory of machines and the knowledge of mechanisms are applied. Combined with the mechanical dynamics analysis software and finite element analysis software, a large amount of calculation and analysis of kinematic and dynamic characteristics of the EBH300 A horizontal roadheader have been done. A detailed study of the motion law and modal vibration of the roadheader cutting part have been done. The main work and achievements are as follows:1. Builded a three-dimensional mechanical structure model of the EBH300 A roadheader,the entity model includes cutting part, loading part, the turntable and body, supporting part, walking part and the assembly parts. The basis data for the further development of the model of the design work of the type roadheader is provided.2. Builded the virtual prototype of EBH300 A horizontal roadheader, according to the engineering design and practical application function, the motion of virtual prototype is realized according to the given input. The foundation for the analysis of the motion simulation and the dynamics and numerical calculation of the roadheader is layed.3. Builded the mathematical model of EBH300 A type horizontal roadheader, the displacement equation is put forward. The model equations express that the position and posture of roadheader is dynamic changes in three-dimensional space, the shape, size and spatial location of the cutting roadway is determined by the movement of the cutting head, and the cutting head position is determined by the position and attitude of the roadheader in the process of roadheader cutting coal and rock.4. Applied mechanical dynamics analysis software to complete the calculated analysis of EBH300 A horizontal roadheader’s displacement, velocity and acceleration, a comprehensive analysis of the impact of the movement position, speed, acceleration of cutting arm, turntable, shovel board after the supporting mechanism on the location and movement of the cutting head has been done, the law is revealed to provide the basis of the remote control, monitoring technology and the development design of EBH300(A) roadheader.5. Builded a three-dimensional mechanical structure model of the EBH300 A roadheader, in order to solve the problem of large complex assembly structure analysis, a large number of detailed pre process of the cutting part, turntable part, fuselage part, shovel board part, support part is completed. Based on the ProE three-dimensional solid assembly model, combined with the modeling function of ansys, the model is a refinement; Using the method of modeling of hexahedron and tetrahedron mixed to effectively control the total number of grid In the area of computer processing ability; the key parts of the mesh refinement, the non critical parts simplified; for different components by using the contact way to build contact, the way is better than the direct use of grid method to simulate actual working conditions. For the key section of roadheader, the intensive of grid cutting part is higher than the grid of other parts, The contact is made by nonlinear contact to ensure the high accuracy and practical. The finite element analysis model of roadheader structure is builded to be real, to be able to reflect the actual machine cutting of key areas, science and simplify the structure of structure vibration redundancy at the same time, reduce the number of grid, avoid excessive computation to solve the convergence.6. Vibration modal is calculated for the whole structure of EBHH300 A transverse axis roadheader, and ten order low-frequency modal along with its characteristics for cutting part is analyzed.7. The vibration test is done based on the prototype supported by the 863 project fund. The vibration test data for the cutting hand and cutting arm are obtained. Amplitude and frequency characteristics along with the vibration velocity and displacement of the test point are obtained by analyzing the measured data which can provide references for doing research on vibration characteristics and analyzing vibration modal of cutting head and cutting arm of the transverse axis roadheader.Innovation Points of the Research:1. The movement position mathematical model and motion displacement equation of the EBHH300 A transverse axis roadheader show the relationship between the dynamic transformation in 3-D space and structural parameters when the roadheader is cutting the coal petrography. Reflect the relationship between the cutting head position and movement and the shape, size and spatial location of roadway.2. Accomplish the calculation of the displacement, velocity, acceleration and inertial force of platform, cutting arm and cutting head with mechanical system dynamics software. Show the law of mechanism movement, which provide the basis for the remote control and monitoring technology and design of the EBHH300 A transverse axis roadheader.3. Build the 3D solid and finite element model of mechanical structure for the EBHH300 A transverse axis roadheader. Complete the finite element analysis of mode of vibration for the cutting part and whole machine of roadheader. Get the data and nephogram of each order modal vibration mode. Analysis of low-order vibration shape influences the dynamic capability of roadheader most. Lay the foundation for this kind of large heavy load roadheader research about the ability to cutting hard coal petrographyand vibration resistance.4. Do vibration test on cutting part of prototype which was development in “863” project. Obtain the vibration experimental data of cutting arm and cutting head. Get magnitude-frequency characteristics and vibration velocity and displacement diagram of measuring point by the spectral analysis and Fourier integral of test data. The conclusions of the exploration are:1. The three dimension solid model and virtual prototype of the EBH300 A cantilever axis roadheader’s mechanical structure constructed are correct which fully reflect the actual structure characteristics and motion characteristics and can be regarded as the basic data model of its research design and development.2. The constructed mathematical model and motion equation of displacement of the EBH300 A cantilever axis roadheader’s moving pose express the relationship between the dynamic changes of tunnel boring machine’s position and pose when developing cutting coal rockin tunnel and its structure parameters. It also reflects the relationship between the position and motion of cutting head and cutting runnel’s shape size and spatial position.3. Analyzing and calculating the displacement, speed and acceleration of EBH300 A cantilever’s rolling table, cutting arm and cutting head with the mechanical dynamics analysis software reveals the mechanism motion principle and can be regarded as the basis of remote control, monitoring, design and development.4. To calculate the whole construction of the EBH300 A cantilever axis roadheader’s vibration mode and analyze the cutting part’s ten order modal and frequency characteristics.5. The vibration test developing on the "863" project prototype obtainsthe experimental data of cutting head and rocker arm through the output signal of the acceleration sensor placed on the measuring point. The measured signal is related to the acceleration sensor installation’s location and direction and the condition of tunneling machine’s measuring point. At the same time errors of sensor and testing system also have different influences on the signal. So the measuring data is the result of the comprehensive effect of multiple factors in actual condition.In the course of this work, the EBH300(A) cantilever’s research and development is conducting with the underground coal mine industrial test at the same time.It has been applicated in many large mining groups, such as the new dragon mine of Xinwen Mining Group, Kailuan Qianjiaying Coal Mine, Heilongjiang Longmay Mining Group in Junde Coal Mine, Xinwen Mining Group Huaheng mine and so on. The underground mining practice has proved that, the EBH300(A) rocky tunnel boring machine can fully adapt driving in the rocky roadway which is within f12 rocky hardness. The rocky road tunneling machine developed in recent years has been successfully applicated in many coal mine roadway.Through a lot of systematic research work, the author has obtained some meaningful understandings. The further analysis of the dynamic characteristics of the EBH300 A cantilever’s entirety and cutting part is very little throughout the world and there are still many issues worthy of a further research. The author would like to continue the above research under the permitted condition, and hopes to get a successful conclusion eventually.