Research On Deflection And Telescopic Ratio Of Double Telescopic Column Of Hydraulic Support

As the key equipment of the fully mechanized working face,the hydraulic support mainly plays the role of supporting the roof and maintaining the mining space.As the main bearing and height adjustment component,the performance of the column directly affects the bearing and supporting capacity of the hydraulic support.With the rapid development of hydraulic supports,higher requirements have been placed on column reliability.This subject studies the variation of column deflection under fluid-solid coupling conditions,and the influence of the column telescopic ratio on the support capacity of the guide ring and the column deflection.It is of great significance to improve the working stability and reliability of ultra-high mining hydraulic supports.Firstly,the dimensionless relation between deflection of the column and elastic modulus,section modulus,calculated length,setting load,liquid viscosity and density,moment was deduced by dimensional analysis method in this paper.The fluid-solid coupling simulation technology(FEM + SPH)was used to simulate the deflections ofφ230mm,φ250mm,φ400mm and φ500mm double telescopic columns,and the unknown quantities in the dimension analysis formula of deflection were solved based on the simulation results,and the applicability was verified.Secondly,the stress distribution and variation law of a φ500mm column under impact load and actual working load were simulated and studied based on the FEM +SPH method.The results show that under two kinds of loads,the maximum stress of the outer cylinder occurs at the lower edge position of the straight section of the outer wall,and the maximum stress of the middle cylinder occurs at the contact position between the cylinder body and the upper edge of the guide sleeve flange.Finally,the relationship between column telescopic ratio,minimum column height and fixed section length was derived,and the influence of fixed section length on deflection of column was studied.The stress calculation method of guide ring proposed by our team was used to study the influence of telescopic ratio and guide ring axial width on the guide ring stress.The results show that increasing the axial width of the guide ring can significantly reduce the stress of the guide ring.With the increase of telescopic ratio of the column,the stress of the lateral guide ring of the fixed section increases in a quadratic curve.