Mechanical Properties Analysis And Linkage Parameters Optimization Of Five-Linkage And Two-Leg Shield Hydraulic Support

In order to solve the problem that the four-linkage stable mechanism hydraulic support cannot adjust its posture independently under the support state at present,a new type of five-linkage stable mechanism hydraulic support is proposed to solve the problems of the large mining height hydraulic support goaf shield being too long,the filling hydraulic support inclined beam being too long,and the insufficient linkage strength of the transition hydraulic support.In this paper,theoretical research,numerical simulation,motion simulation,finite element calculation,experimental verification and other research means and methods are comprehensively used to analyze the kinematic performance and mechanical characteristics of the five-linkage and twoleg shield-type hydraulic support,optimize the linkage length of the five-linkage and two-leg shield-type hydraulic support and other related structural parameters,study the static bearing characteristics of the five-linkage and two-leg shield-type hydraulic support,and produce a physical prototype of the five-linkage and two-leg shield-type hydraulic support,at the same time,relevant parameter experiments were conducted to verify.The main research results of this paper are as follows:(1)The plane linkage model of the five-linkage and two-leg shield-type hydraulic support is established,and the equations of the main mechanical parameters,such as the linkage force,the attitude adjusting jack force,the support resistance of the hydraulic support,are derived.The effects of the linkage length,the tilt angle of the column,the pressure angle,and the friction coefficient on the bearing characteristics of the hydraulic support are analyzed.Established three different types of five-linkage and two-leg shield-type hydraulic support skeleton models for thin coal seam,medium thick coal seam,and large mining height,conducted motion simulation and mechanical analysis,and studied the changes in the linkage force,attitude adjusting jack force,support strength,working resistance,and face-to-tip distance of three typical fivelinkage and two-leg shield-type hydraulic supports.Compared with the four-linkage and two-leg shield-type hydraulic support,the kinematic performance and mechanical characteristics of the five-linkage and two-leg shield-type hydraulic support were summarized.(2)A mathematical model for optimizing the parameters of the five-linkage and two-leg shield-type hydraulic support was established,with the objective function of minimizing the absolute sum of linkage forces and minimizing the weight of the linkage,combined with the minimum variation of the beam end motion trajectory,the fivelinkage mechanism was optimized.Develop a mechanical analysis program to automatically generate the variation curve of the linkage force and the face-to-tip distance of the five-linkage and two-leg shield-type hydraulic support,in order to find the unfavorable bearing position of the hydraulic support and determine the reasonable working height range of the hydraulic support.The effect and influence of linkage length on the linkage force,attitude adjusting jack force,support strength,and face-totip distance were analyzed.A "normal fixation,abnormal release" control method was proposed to solve the problem of large swing amplitude of the beam end motion trajectory of the five-linkage and two-leg shield-type hydraulic support,and to optimize the support performance of the five-linkage and two-leg shield-type hydraulic support.(3)A three-dimensional solid model of the five-linkage and two-leg shield-type hydraulic support was established,and finite element strength calculations were conducted.The bearing characteristics of the hydraulic support were analyzed under two working conditions: torsion of the canopy and eccentric loading of the canopy.The stress distribution cloud diagrams of different components such as the canopy,goaf shield,linkage,and base of the five-linkage hydraulic support were obtained,and the stress distribution patterns of the five-linkage and two-leg shield-type hydraulic support under different conditions were given.(4)We processed and produced an experimental prototype of the five-linkage and two-leg shield-type hydraulic support,tested the kinematic performance of the fivelinkage and two-leg shield-type hydraulic support,and tested the variation curve in the beam end motion trajectory of the five-linkage and two-leg shield-type hydraulic support,verified the correctness of the theoretical analysis.