Study On Vibration Characteristics Of Drilling System Of Power Head Drilling Rig In Coal Mine Tunnel

The drilling rig in coal mine tunnel is a drilling equipment widely used in the field of underground safety in coal mines.It has become the leading model for underground tunnel drilling construction in coal mines with small size,light weight and high degree of mechanization.In recent years,problem of reliability and safety of drilling rig has become more and more complex.Non-uniform wear of transmission parts,breakage and loosening of fasteners and failure of drilling tools caused by abnormal vibration are becoming more and more serious.The drilling system,mainly composed of drilling power head and feeding device,is the core of drilling rig,and its dynamic performance research is important content of tunnel drilling rig.Taking ZDY1200 S split tunnel drilling rig and ZDY6500 LQ crawler drilling rig as the research object,this paper studies the vibration characteristics of its drilling system through theoretical analysis,finite element simulation and experimental test.The main conclusions are as follows:(1)The dynamic model of two-stage gear transmission of power head is established,the vibration differential equation of two-stage gear are listed,and the transmission gear meshing frequency is calculated.The main feeding forms of tunnel drilling rig are analyzed,and the dynamic equations of feeding device are listed.(2)Through the finite element numerical simulation of the drilling system,the natural frequency and modal vibration mode of the drilling system are obtained.The Rayleigh damping coefficient of the drilling system is calculated.Combined with the two drilling conditions of high and low torque,different torque and feed force are applied at the chuck and feed oil cylinder,and the harmonic response results of the drilling system and system optimization measures are obtained.(3)Based on the drilling rig vibration test system and performance test platform,the vibration curves at different positions of the drilling rig and the operating parameters of the drilling rig under corresponding working conditions are tested according to the test scheme and equipment.Through the time domain analysis method,the ZDY1200 S is analyzed,and the time domain waveform variation law of vibration at different positions of the drilling system is obtained.Increasing a certain load can reduce the vibration amplitude of the drilling rig,and the vibration increases obviously when the rotating speed is increased.(4)Through the frequency domain analysis method,the ZDY6500 LQ is analyzed,the main excitation sources,frequency spectrum characteristics and the vibration variation law of drilling rig under different working conditions are obtained.Power head reducer and plunger pump are the largest excitation sources of the drilling rig.Low speed and high torque load reduces the total vibration of reducer box by3.11%～7.27% compared with no-load.Under this condition,the effective power of the whole machine is greater than 50%.The research results enrich the dynamic theory of coal mine mechanical system,and provide a technical guarantee for optimizing the structure of the drilling rig,and ensuring the safety and efficient operation of the drilling rig.