Directional Drilling Deflection Research Oncoal Auger Working Mechanism

Coal is a kind of non-renewable energy resources. In order to maximize its exploitation and utilization efficiency and avoid the waste of resources, the exploitation and utilization of thin and ultra-thin coal seam has become an important task we have to face during realizing the sustainable development of economy and society. Coal auger is a new type of mining equipment used in thin coal seam, and directional drilling performance of its working mechanism become the key issue in the equipment service life and drilling efficiency. Because of this, theoretical analysis, multi-body dynamics simulation, and modeling test research are adopted in this dissertation to study the stability, modal, deflection and vibration characteristics of the working mechanism. How factors like structure, drilling depth and load influence the directional drilling performance is also analyzed. New drill rod stabilizer and directional control mechanism using in five bits working mechanism are put forward to ensure directional drilling.Based on some reasonable simplifications and hypotheses of working mechanism, buckling and helical buckling mechanical models of working mechanism are established. Their buckling equilibrium equations are derived and relationship between critical buckling load and critical speed of working mechanism are obtained. Research provides theoretical basis for design and study of coal auger working mechanism.Restraint and prestressed modal analyses of working mechanism are carried out using ANSYS-Workbench based on modal analysis theory. Natural frequency and modal vibration mode of working mechanism under conditions of different structures, different drill rod lengths are obtained. Influence of various factors on working mechanism natural frequency and vibration mode is also analyzed to provide reference and guidance improving the global and local stability of working mechanism.Rigid-flexible coupling dynamic model of coal auger working mechanism are established using dynamics analysis software ADAMS. Deflection and vibration characteristics of working mechanism with different structure, different drilling depth and under different load conditions are simulated separately. Research shows that: anti-deflection capability, vibration characteristics and deflection force of five bits working mechanism is obviously superior to the three bits working mechanism form; with the increasing of drilling depth, deflection and vibration of working mechanism in x and y direction are increasing and trend to be stabilized gradually, and the deflection in y direction is much larger than that in x direction; working mechanism occur serious unilateral deflection when it is affected by partial load. It can effectively reduce the deflection and vibration of working mechanism and minimize the number of stabilizer to weaken the influence in coal transportation when the drill rod stabilizer is arranged every 5 drill rods and air ducts. Simulation research result provides basis for diminishing deflection and vibration of working mechanism and improving the reliability and service life of coal auger.Experimental study is conducted. Simulated drilling test bed of three bits working mechanism is designed based on coal and rock cutting test bed, and a test system for the test bed is constructed according to parameters needed in the test. Drilling model test of three bits working mechanism under different drilling depths is carried out, and propulsive force, drilling torque and deflection and vibration characteristics of working mechanism are obtained. Model test result provides the experimental basis for reducing the deflection and vibration of coal auger working mechanism. It also has important reference value in realizing directional drilling and improving drilling efficiency of coal auger.