| Gear systems are extensively used in contemporary mechanical transmission,but they are difficult to machine and work in sophisticated environments,so the gear system often generates failures,cracks,pitting and wear are unavoidable failure factors of the gear,these failures will make the overall operating efficiency of the mechanical structure reduced,there is also a corresponding effect on the dynamic characteristics of the gear system.Therefore,it is especially important to analyze the vibration characteristics of gear trains under cracking,pitting and wear faults.In this thesis,the vibration of faulty gear systems under the influence of friction factors is mainly investigated.The vibration analysis of cracked gear system with friction and eccentricity: firstly,we establish the force model of gear with crack depth of 1mm,2mm and 4mm,solve the vibration differential equation,and the meshing stiffness of gear teeth at various crack lengths is analyzed using the energy approach;investigate the dynamic characteristics of cracked gear system when the friction coefficient is 0.01 and 0.02 respectively;analyze the influence of different eccentric distance on the dynamic characteristics of gear under friction condition.The effects of different eccentric distances on the dynamic characteristics of gears under friction conditions are analyzed.The results show that the vibration reaction of the gear trains is enhanced with the increase of friction as well as the increase of crack depth.Vibration analysis of pitting gears under different friction parameters and different eccentric distances: Firstly,a pitting gear model is established,and the pitting fault is classified into three conditions: slight,moderate and severe.The results show that the aggravation of the pitting condition and the increase of the friction coefficient will increase the friction force between the gears,which will lead to a greater load on the gears and will result in an enhanced vibration response between the gears and a change of the period.The effects of friction parameters and different eccentric distances on the vibration characteristics of worn gears: establish gear dynamics models under 30μm,60μm and 90μm of wear,calculate the meshing stiffness of the gearing system under different wear amounts and the meshing stiffness under different operation times,and analyze the meshing stiffness;the analysis of various friction factors and different eccentric distances on the dynamic characteristics of the gear system under different wear amounts.The results show that an increase in the friction coefficient leads to an increase in the wear and thus an increase in the damping between the gear trains,the stabilization of gear vibration will decrease,the amplitude will increase and the responsiveness will enhance. |
PDF Full Text Request