Analysis On Braking Characteristics Of Mine Hoist And Research On Inertia Test Bed

As the medium to realize the economic value of underground mineral resources,mine hoist plays an important role in mining and production.With the rapid development of China ’ s national economy,in order to meet the production needs of high indicators,the vibration characteristics and braking performance of mine hoist system under high requirements are also tested,which also brings great challenges to relevant researchers.The vibration characteristics and braking performance of hoist under complex working conditions had become the focus of current research.However,due to the large volume of lifting equipment and the objective conditions of diverse and complex mine environment,it is difficult to carry out field tests on the braking characteristics of mine hoists,and the test data are easily affected by various field environmental factors,so it is difficult to grasp the influence of main parameters on the research object.In view of the above problems,this study takes the JKMD3.25-4(II)type landing friction mine hoist as the research object,considering the physical constraints between the components,contact characteristics and the elastic modulus of the wire rope,the rigid-flexible coupling dynamic simulation model of the hoist multi-body system was established,and the correctness of the model was verified by field tests.The variation of friction torque between friction drum and wire rope under different operating parameters was studied by simulation model,which provided a basis for the design of hoist inertia test bench.Based on the similarity theory and model test,a hoist inertia test bench was built to test the performance of the proportional control valve in the hydraulic braking system,and relevant experimental tests were carried out by using the test bench.The results show that:(1)Through the field test of the prototype mine hoist,the comparison between the results and the simulation analysis shows that the test and simulation vibration acceleration curves of the actual mine hoist container in different directions have the same characteristics,and at the same time,there is the same oscillation phenomenon in each stage of the operation process.Therefore,the rigid-flexible coupling dynamic simulation model of the multi-body system of the hoist can be compared with the actual hoist.(2)The lifting height,stable operation speed,lifting load and braking deceleration will affect the braking performance of the hoist.The friction torque in the stable operation stage is related to the lifting load,although there are fluctuations but relatively stable.Both the lifting height and the lifting load will affect the stability of the friction torque in the braking stage.Increasing the lifting height and the lifting load will increase the fluctuation amplitude of the friction torque and lead to the deterioration of its stability.The increase of the braking deceleration will increase the inertia force needed to overcome when braking,and also make the friction torque unstable.During the holding and stopping stage,the friction torque of the friction drum after stopping has the characteristics of attenuation and oscillation,and finally tends to be stable(load static torque).(3)The dynamic and static test results of proportional control valve show that the threeway proportional pressure relief valve has good dynamic and static performance and can control the pressure accurately and quickly;The braking test results of hoist inertia test bench show that the speed is slightly lagging behind the torque in the early braking stage.In the braking stage,under the same braking pressure,increasing the test stable speed and flywheel load inertia will increase the braking stop time;At the same time,when the stable speed of the test increases,the uneven contact between the brake disc and the friction material leads to the periodic violent fluctuation of the torque curve,and the amplitude of the fluctuation is proportional to the braking pressure within a certain range.In the braking and parking phase,the torque curve shows the characteristic of attenuation oscillation.The above tests verify the feasibility of the hoist inertia test bench,which can provide a relatively convenient test system for the study of hoist braking performance.