Research On Brake Pad Eccentric Wear Of Foundation Brake Rigging Of The Mid-Low Speed Maglev Train

With the advantages of low vibration and noise,good environmental protection,flexible line selection,safe operation and low comprehensive operation cost,mid-low speed maglev traffic has gradually become an important way of travel in urban rail transit.However,the phenomenon of eccentric wear of the brake pads on the train operating site seriously affects the reliability of the train brake system,and the eccentric wear of the brake pads shortens the service life of the brake pads,which increases vehicle maintenance costs.In view of the above problems,it is difficult to conduct field test observation and the test cost is high,so the operation feasibility is low.In this paper,based on the theory and technology of multi-body dynamics,in the simulation platform RecurDyn,the actual running state of the train foundation brake rigging is simulated,and the eccentric wear trend of the brake pad is evaluated by extracting the contact force distribution of the brake pad surface of the foundation brake rigging and the collision contact times between the upper and lower ends of the brake pad and the track,so as to explore the eccentric wear law of the brake pad,and provide the corresponding improvement of the foundation brake rigging method.The main research contents and results include:Firstly,it analyzes the running mechanism and braking mode of mid-low speed maglev trains,as well as the structural composition and braking principle of the foundation brake rigging.This analysis method is used to analyze the stress of the key components of the foundation brake rigging and the four working states of the device.This analysis has laid the theoretical foundation for the virtual prototype modeling and multi-body dynamics simulation of the foundation brake rigging.Then,according to the movement form of the foundation brake rigging,two types of simulation experimental schemes for straight-line braking condition and complex operating condition were designed.The straight-line braking condition includes three kinds of simulation schemes,namely conventional brake,landing brake and brake pad eccentric wear.The complex operating condition includes three kinds of simulation schemes,namely vertical vibration,lateral vibration and swing.A total of 152 simulation experiments are conducted for all simulation schemes.Using the multi-body dynamics simulation software RecurDyn to model the foundation brake rigging and reproduce the working state of the b foundation brake rigging in actual operation.Through the comparison of the field data and simulation experimental data,the reliability of the simulation model is verified.Finally,the simulation experiment of the foundation brake rigging is carried out.The simulation results of straight-line braking condition show that: With the increase of the clearance of the shaft hole,the eccentric wear trend of the lower end of the gate pad will be intensified.Therefore,in the process of design,the clearance of the axle hole should be set reasonably,so as to weaken the eccentric wear trend of the brake pad.There is a clockwise deflection phenomenon around the installation center of the outer pad holder,which leads to the eccentric wear trend of the upper end of the pad.By reducing the weight of the dowel,the clockwise deflection degree of the pad holder can be effectively reduced,and the eccentric wear trend of the upper end of the outer pad can be weakened;The drop off process has a greater influence on the eccentric wear trend of the brake pad of the foundation brake rigging.Increasing the spring damping properly will reduce the contact force difference between the upper and lower ends of the brake pad,thus weakening the eccentric wear trend of the brake pad surface;The sensitive factor that affects the tendency of eccentric wear of brake pad is the clearance of shaft hole in the dowel bar.Therefore,in the maintenance specification of the foundation brake rigging,the maintenance standard for the clearance of shaft hole in this part is established.The simulation results of complex operating conditions show that.The vibration frequency and amplitude of the body beam electromagnet will affect the eccentric wear degree of the brake pad of the foundation brake rigging.By increasing the damping of the spring inside the beam support seat of the car body,the impact of the vibration frequency and amplitude of the electromagnet on the contact collision between the brake pad and the track can be reduced,and the eccentric wear trend of the brake pad can be weakened.In this paper,the analytical method and multi-body dynamics simulation experiment are used to provide theoretical and technical support for the research of the brake pad eccentric wear of the foundation brake rigging of mid-low speed maglev train,which can effectively improve the safety and economyof vehicle braking.