Research On A High Capacity Unloading Valve With The Characteristics Of Impact Resistance And Double-stage Protection For Hydraulic Support

Aiming at the current development trend and application field of unloading valve,based on the design concept and structural characteristics of the traditional relief valve,the structure and working principle of double-stage double-stage protection high capacity unloading valve has been analyzed.According to the actual working conditions,we designed a kind of anti shock double-stage protection high capacity unloading valve which can meet the requirements of different working conditions.According to the relevant standards of unloading valves and the requirements of pressure and flow,a structural model of double-stage protection high capacity unloading valve is preliminarily determined,and the key dimensions are preliminarily designed.In addition to the effect of orifice diameter for double-stage protection high capacity unloading valve dynamic characteristics of unloading valve in the structure,and adding a damping hole adjusting sleeve,by adjusting the damping hole adjusting sleeve and the main spool up to change the amount of damping hole diameter,high capacity unloading valve with different damping the role.Application of module analysis of step dynamic characteristic curve of the whole structure of double-stage protection high capacity unloading valve under the double-stage protection high capacity unloading valve is designed with a smaller pressure rise time,pressure overshoot,stable pressure time and unloading time,but also can meet the requirements of the original design in the stream the amount of.Focus on the analysis of the mutual influence of inlet cross-sectional area,differential area,spring stiffness,spring pre compression between the influence on the double-stage protection high capacity unloading valve,the other two stage differential spool with different dimensions due to the selection of quality differences of valve dynamic characteristics have certain effect,comparative analysis of high capacity unloading valve of different needs numerical selection on the main spool mass and damping hole diameter of the dynamic characteristics.According to the analysis we can know that the import unloading valve cross-sectional area,differential area,spring stiffness and pre compression effect on the characteristics of the spring unloading valve,and they are not alone affects the characteristics of the valve,so the design process should be according to the design requirements.When considering the relations between the structure parameters of the the dynamic characteristics of the unloading valve,selecting the appropriate value,the unloading valve can have good dynamic characteristics,to ensure the stability and reliability of unloading valve..Simulation analysis of hydraulic support column loop,adding the factor of deformation of column cylinder,the roof subsidence as the system input,so as to get the roof impact shock resistance under the design of two-stage protection valve: system pressure quickly stable in unloading valve setting,the system has excellent dynamic performance,with the the impact of the disappeared,unloading valve closes quickly,it can be effective for the post unloading loop system,guarantee the stability of hydraulic support equipment.In addition,the impact resistance characteristics of the two stage protection large flow unloading valve and the conventional small flow unloading valve are compared and analyzed,which shows the advantages of the two-stage protection large flow unloading valve.Simulation analysis of hydraulic support column loop,adding the factor of deformation of column cylinder,the roof subsidence as the system input,so as to get the roof impact shock resistance under the design of double-stage protection high capacity unloading valve: system pressure quickly stable in unloading valve setting,the system has excellent dynamic performance,with the the impact of the disappeared,unloading valve closes quickly,it can be effective for the post unloading loop system,guarantee the stability of hydraulic support equipment.In addition,the impact resistance characteristics of the double-stage protection high capacity unloading valve and the conventional small flow unloading valve are compared and analyzed,which shows the advantages of the double-stage protection high capacity unloading valve.According to the laboratory conditions,build the double-stage protection high capacity unloading valve impact test rig,respectively,the overall simulation and impact test of the simulation data and the experimental results were compared and analyzed: steady pressure unloading valve for 44 MPa,the steady flow is 950 L/min,the pressure overshoot and flow overshoot can satisfy the design and related the requirements of the standard,and the pressure and flow rate of rise time is about 20 ms,with good anti shock characteristics of double-stage protection high capacity unloading valve visible design.