| Intrinsic safety equipment plays an important role in environment with explosive risk such as coal mine.Because of its low power consumption,high reliability,compact and light weight,it is widely used in communication,test system,and hydraulic control system under the coal mine.Intrinsically safe directional solenoid valves can be used in pilot control systems of hydraulic systems or directly control the switching of small hydraulic circuits,and have a wide range of applications.Based on the study and summary of the relevant design and optimization methods of solenoid valves and the design and checking methods of intrinsically safe equipment,a 6 diameter intrinsically safe solenoid valve is designed and the structure of solenoid and spool is optimized.This paper mainly includes:(1)The characteristics of intrinsic safety technology are summarized and briefly described,and the design difficulties of intrinsically safe solenoid valve are determined,which are mainly increasing the force of solenoid and reducing the resistance of spool.The design requirements are proposed and the research scheme for improving the solenoid force through local sensitivity analysis,orthogonal test and global optimization is determined.A method for analyzing and optimizing the forces acting on the valve spool by means of CFD simulation is proposed.(2)Experience design methods of directional spool valve and solenoid are summarized.A 6 diameter intrinsically safe directional solenoid valve is designed by combining the design of directional spool valves and intrinsically safe solenoids.The methods for verifying intrinsic safety characteristics of iron-core inductive circuit with freewheeling diode are summarized and the designed solenoid is checked.(3)The simulation model of intrinsically safe solenoid was established and the influence of various size factors of solenoid on the output force of solenoid was studied.Based on the deformation design idea,the change of the magnet suction characteristics when the dimension factor changes is studied and the local sensitivity of each factor is calculated by the central difference method to get the key dimension factor.Orthogonal test and range analysis were carried out to get the most critical dimension factor and better design value.Combining MATLAB with Maxwell,the output force of solenoid is optimized globally by genetic algorithm to get better design value.(4)The force analysis of the spool is carried out,and the simulation models of gap flow path,PA flow channel and BT flow channel of the valve are established.The clamping force,steady-state hydrodynamic force,axial hydraulic force and radial hydraulic force of the spool under different pressure differences and sizes are simulated and analyzed.The effects of some structure dimensions of PA and BT channel on spool force and flow were studied and better design values were obtained.The clamping force is reduced by optimizing the position of equalizing groove,and the radial,steady-state and axial hydraulic forces applied to the spool in PA and BT flow channel are optimized by improving the structure and size of the spool.(5)Tests were carried out on the designed intrinsically safe solenoid valve,and the differences between simulation and test results were analyzed.The optimization results of solenoid force characteristics are verified and the reliability of the switching action is tested.After optimization,the reliability of switching action is improved to some extent.Finally,the research work of this paper is summarized and the main direction of follow-up research is proposed. |
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