Structural Dynamics Analysis Of Roadheader And Vibration Suppression Research Of Electric Cabinet

When the roadheader cuts coal and rock,the working environment is bad,the working condition is complex,the cutting load is changeable,and it is easy to produce violent vibration.Violent vibration will not only cause the wear of pick,fatigue damage of key parts,failure of hydraulic system,but also easily cause the failure of electrical components inside the electric cabinet,which will lead to the decline of the working efficiency of the roadheader.Therefore,the vibration characteristics of each part of the roadheader,especially the electric cabinet,under the condition of cutting rock are studied,and on this basis,effective vibration suppression measures are put forward.Firstly,the simplified mechanical model and differential equation of motion of the roadheader are established.Based on this theory,the complete model of the roadheader is rationally simplified,and the restrained modal analysis of the whole machine is carried out.The main modal frequencies and modes of the components of the roadheader are obtained.Secondly,the rock cutting simulation is carried out in the display dynamics analysis software,and the three-way cutting load and torque of the roadheaderunder the cross cutting condition are obtained.The rigid-flexible coupling model of the roadheader with cutting arm,turret,frame and rear support as flexible body is established in the finite element software,and the dynamic analysis is carried out by applying load to the model.The vibration characteristics of the key components of the roadheader are obtained: the vibration of the cutting head and cutting arm is violent around 14 Hz,28Hz and 63Hz;the vibration of the turntable and frame is weak,and there is no obvious peak value in the spectrum diagram;the rear support and electric cabinet vibrate violently under 25 Hz,62Hz and 125 Hz.By analyzing the forced vibration response of the eight vertices of the electric cabinet,the excitable modes of the electric cabinet under the transverse condition are obtained.Then,by changing the stiffness parameters of cutting arm,turret,frame and rear support in forced vibration simulation,the vibration response of the roadheader under the new parameters is obtained.The influence of the stiffness changes of key components on the vibration of the roadheader is analyzed from two aspects: the change of stiffness matrix in the motion differential equation and the change of the natural frequency of the components.It is concluded that properly increasing the Y and Z stiffness parameters of the frame and rear support is helpful to reduce the vibration of the roadheader,especially the45-70 Hz and 110-130 Hz of the electric cabinet,but the restraint effect on the vibration below 25 Hz is not obvious.Finally,on the basis of analyzing the vibration characteristics of the electriccabinet,aiming at the existing problems of the shock absorber,the structure of the old shock absorber is improved.Furthermore,through harmonic response analysis,it is found that the new conical shock absorber is better than the old one.The research results provide a theoretical basis for the vibration suppression research of roadheader and electric cabinet.