Design And Research Of Anti-impact Brake System For Permanent Magnet Hoist

The hoist brake system is significantly essential to ensure the safe operation of hoist system and respond to unexpected accidents.The function of hoist brake system is increasingly prominent with the deepness,large-scale and automation development of mines.The permanent magnet hoists,has been revolutionary changed for traditional hoist by omitting the components of reducer,coupling,lubrication station.Meanwhile,it also has energy conservation and reliability recognized by the industry.In the future,it will be applied in deep mine hoist system.The brake system is also an considerable part to ensure the safety of permanent magnet hoists.Firstly,the traditional hoist braking system is usually susceptibility to malfunction with false braking and non braking,which cause serious impact or over rolling and over releasing accidents,thus to bring potential danger for safe operation of hoist.In order to solve this problem,the research topic of the antiimpact brake system of the permanent magnet hoist is put forward in this paper.The hydraulic system of "n + 1" anti-impact braking with different output points is devised based on the concept of redundancy design.In this system,two sets of load sensitive variable displacement pumps,one for use and one for standby,are used as the power components to ensure the pressure balance of each disc brake and reduce the heating of hydraulic system.Secondly,the overall structure of supporting electric control system of antiimpact hydraulic system is designed,which adopt dual PLC master-slave design,each channel communicate with the master PLC through the expansion module to ensure independence between channels of anti-impact braking system.Meanwhile,the hardware composition and PLC control program flow of the antiimpact brake electronic control system are designed,and meet the control requirements of permanent magnet hoist working brake and safety brake.Then,the working braking characteristics and safety braking characteristics of anti-impact braking hydraulic system are researched in this paper.The simulation model of the critical components of brake system and the load sensitive variable displacement pump are built in AMESim.Meanwhile,the model of anti impact brake hydraulic system is built to analysis the operation processes,including the releasing,the sticking and the applying of the system.The results show that the brake gap is less than 2mm,brake air operation time is less than 0.3s,which are satisfied to the design requirement in ‘Coal Mine Safety Regulations' and conformed to the tested results.Furthermore,the speed closedloop PID control strategy is designed and the simulation model of safety braking channel and standby channel is built.The safety braking characteristics under different working conditions of no load,heavy load,high speed and low speed are researched,respectively.The results show that the safety braking control effect of the system is excellent and fulfill the requirements of the regulations.The influence mechanism of channel switching and different output modes on braking performance is obtained.Finally,the experiment of the permanent magnet hoist is studied.The 3-D model and scene of the anti-impact braking system of the permanent magnet hoist are established.The virtual simulation experiment platform and its humancomputer interface are developed to achieve the cognitive learning of permanent magnet hoist and virtual modeling function of hydraulic system.The start stop control operation condition of permanent magnet hoist is simulated.The function of the contrast of primary brake,secondary brake and constant deceleration brake,and the sliding between rope and rope lining are realized.