| With the rapid development of integrated mining technology,coal mining work has put forward higher requirements for efficient transportation of equipment underground.However,at present,most of the underground equipment trains rely on the traditional winch pulling wire rope traction transportation method.This method requires the laying of the appropriate track and the installation of a column return winch.Its inefficient and cumbersome steps,and the method is prone to problems such as running and falling off the road,increasing the safety risks of the mining process.Therefore,this paper designs a new type of roadway step-type hydraulic support as a traction device for the problems arising from the traditional equipment train traction method.It can not only avoid the above problems,but also realize the straight line travel and steering function of the equipment train in the tunnel,increase the efficiency of equipment transportation and improve the safety of the operating environment.It is of great significance to solve the problem of safe and efficient transportation of coal mine equipment and to achieve the purpose of increasing production and capacity.Firstly,Solidworks is used to build a 3D model of the whole machine of the step-type hydraulic support and introduce the structure and working steps of each part.Establish a mathematical model of the equilibrium zone and obtain the geometric relationship between the dimensions of the hydraulic support.Under three different working conditions,the hydraulic support structure is optimized using simulation with the objective function of minimizing the stress value and the weight of the equipment.Then,the optimal solution of the hydraulic support structure size is derived for each working condition.The mathematical models of straight-line travel and in-road steering are established respectively according to the conditions required for the work of the hydraulic support.The values of the bottom lift force and the supplementary support force of the roof beam and roof plate during straight line travel and the single steering angle when the brace is in steering motion in the roadway are calculated.Hertz collision theory is used to establish the model,and ADAMS software is used to simulate the multi-body dynamics of the hydraulic support traction equipment train traveling in a straight line and steering in the tunnel to verify the correctness of the mathematical model.Using AMEsim to design the hydraulic system for linear travel of the bracket,the dynamics model is established by ADAMS,and the two are simulated jointly.To study the flow rate and hydraulic rod stroke variation of bottom lift cylinder and stepper cylinder under different pressure.If the set pressure of the cylinder safety valve is less than the normal working pressure of the cylinder,there will be unloading phenomenon and the stroke of the hydraulic rod will be shorter than the stable working pressure.The pressure variation of the two cylinders working under normal hydraulic condition was analyzed,and the value of the bottom lifting force obtained was only 4.2% different from the theoretical value.Use Hypermesh to soften the cover beam and base column nests with larger forces,and establish a rigid-flexible coupling model.The influence of the gap value and friction coefficient of the rotating pair and the connection method on the operating stability of the bracket was studied.And it was concluded that the copper bushing connection method has the best effect.Based on the dynamic stress analysis of the hydraulic support,it was found that the stress distribution of the cover beam showed two kinds of changes during forward and steering.The maximum stress values in forward motion and steering motion were obtained respectively,which were smaller than the yield stress of the material and could achieve the strength requirement of the material. |
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