Hoist Emergency Braking Characteristics Based On Electromechanical-hydraulic Coupling Model

Mine hoist is widely used in various mines as a transportation hub connecting up and down shafts.Its main function is to transport mineral resources and personnel equipment,which has an important impact on the efficiency and safety of mine production.Emergency braking is the most critical and the last line of safety when the mine hoist encounters an unexpected situation.Due to the flexible characteristics and elastoplastic deformation of the wire rope,and the complex working environment,the dynamic characteristics of the mine hoist during emergency braking are extremely complicated,and the shock and vibration phenomena are more serious,which is easy to cause the wire rope damaged.There are even serious consequences of slacking,slipping and breaking of steel ropes,which will cause huge economic losses and casualties.Obviously,how to reduce the braking impact during emergency braking and improve the reliability and stability of the braking system is a problem that large-scale lifting equipment needs to solve urgently.In view of the above problems,this study takes JKMD3.25-4(?)floor-type friction mine hoist as the research object,establishes a system mathematical model,and on this basis,proposes a electromechanical hydraulic coupling system collaborative simulation method.Combined with Recur Dyn and AMESim software,and considering the non-linear factors such as the contact characteristics of various components,the flexible characteristics of steel wire rope and brake shoe,a electromechanical hydraulic coupling simulation model of friction hoist lifting system and constant deceleration braking system is established.The correctness of the coupling simulation model is verified through experiments,and the coupling effect between the hoisting system and the braking system is studied by using the coupling simulation model.The results show that:(1)The lifting parameters affect the dynamic characteristics of the system by changing the friction torque between wire rope and pulley.During the constant deceleration braking process,for the lowering conditions,the larger friction torque between wire rope and pulley can cause more serious slippage of the wire rope,and the friction torque increases with the increase of the transportload and the braking deceleration.For lifting conditions,the smaller friction torque between wire rope and pulley can cause the worse pulley speed following.The friction torque increases with the transport load and decreases with the braking deceleration.The direction of the friction torque before and after braking will change suddenly,which will easily lead to the wire rope slacking.(2)The braking parameters have a non-monotonic effect on the system dynamic characteristics.Too large or too small volume of the hydraulic pipeline volume and ratio of the double closed loop proportional coefficient will deteriorate the system dynamic characteristics and even lead to the wire rope slipping.And comparing with the lifting parameters,the improper braking parameters will make the longitudinal vibration of cage more serious.