Research On Dynamic Characteristics Of Key Structures Under Typical Working Conditions Of Roadheader

With the rapid development of China's coal industry,the demand for coal is increasing,the corresponding coal mining volume is also increasing,and the underground mining environment is also getting worse.The working efficiency,safety,and reliability of the roadheader are also raised.Requirements,and the boring machine has good dynamic characteristics is the key factor to ensure that the boring machine has the above performance.The vibration of the roadheader is the main reason for the failure of the roadheader,the mechanical failures of the roadheader caused by vibration mainly include: the vibration fatigue damage of the supporting part of the turntable;the leakage of the oil cylinder due to excessive transient dynamic pressure;the hole diameter of the connecting pin of the oil cylinder becomes larger due to vibration,which affects the stability of the connection;Due to the severe vibration of the lampshade,the screws often fall off and the lampshade is damaged;the gears in the cutting gearbox are affected by the vibration and the transient speed of the gear speed,resulting in damage to the gear pitting corrosion.The object of this study is the EBZ300 longitudinal axis cantilever roadheader.It mainly studies the cutting arm and rotary table and other components that play a major role in the process of the roadheader.The dynamic characteristics of these components determine the reliability of the roadheader Sex and stability.In this subject,the cutting object is set to a rock with high hardness,so it is easy to generate a large impact load during the cutting process of the roadheader,along the vibration transmission path,which will cause the cutting part of the roadheader and the main body to vibrate,causing fatigue damage and failure of the above components,which in turn affects the working efficiency,safety and reliability of the roadheader.Therefore,this paper mainly studies the vibration characteristics and stress characteristics of the key components of the roadheader under the typical working conditions of the roadheader,including cross-section and drilling conditions.Firstly,according to the two-dimensional drawings provided by the enterprise,the three-dimensional model of the whole machine of the roadheader is established in UG and simplified appropriately,and then the constraint modal analysis of the whole machine of the roadheader is carried out in Workbench to obtain the main mode of the whole machine The frequency and vibration mode provide a reference for the subsequent analysis of the vibration of key components of the roadheader.Secondly,the constitutive model of the cutting head and rock wall established in UG is imported into ANSYS to establish the finite element model of the cutting head and rock wall,and then the cross-section and drilling conditions are respectively carried out in LS?DYNA The cutting head of the tunneling machine cuts the rock to obtain the external impact load on the cutting head,and provides load data for the subsequent rigid-flexible coupling dynamics simulation of the roadheader.Finally,the cutting part and the modal neutral file of the turntable are established in ANSYS respectively,and imported into ADAMS to conduct the rigid-flexible coupling dynamic analysis of the machine with the cutting part as the flexible body and the turntable as the flexible The rigid-flexible coupling dynamic analysis of the whole roadheader is used to obtain the vibration characteristics and stress characteristics of each key component of the roadheader.The simulation results show that under the conditions of cross-section and drilling,the cutting section of the roadheader vibrates at about 12 Hz,19 Hz,and 52 Hz.The stress of the cutting gearbox and the motor box is relatively large,and the stress of the cantilever section is relatively small.The maximum stress of the cutting part is concentrated on the position of the pin connecting the cutting gearbox and the lifting cylinder,and its maximum stress is much smaller than its allowable stress,which proves that the structural design of each part of the cutting part meets the strength requirements.Under two working conditions,the vibration frequency of the turntable is concentrated at 12 Hz,19 Hz,and 39 Hz,and under the two working conditions,the maximum stress of the turntable is mainly concentrated at the position of the pin connecting the turntable and the lifting cylinder.The maximum stress is also less than its allowable stress,which proves that its structural design is reasonable.The results of this paper provide a theoretical basis for the research on the vibration reduction design of key components of the roadheader and its structural optimization and improvement.