Evolution Of Defect Gear Surface Wear Process Under Heavy Load Mechanism Research

Gearboxes are mainly used to adjust different speeds,and often works for a long time under the conditions of heavy load,high speed,chemical corrosion and so on,it often leads to various gear failures,such as abrasive wear,fatigue wear,gear breakage,which will eventually lead to the scrapping of the gearbox.If the faulty gear is replaced in time before the gear fails,resources can be maximized while ensuring safety.Therefore,in order to explore the occurrence of gear defects,gear wear status under different load conditions,and wear migration changes near the defect point,this paper uses oil analysis technology and vibration waveform analysis as an aid to study the evolution of defective gears under different loads.This paper uses SOLIDWORKS to model the gear teeth with 1,2,and 3 pit defects,and uses ABAQUS for dynamic analysis,the stress distribution of different tooth surfaces was observed.On the fatigue wear test bench,three sets of wear experiments were carried out on the normal gear with constant load,the defective gear with constant load,and the defective gear with step variable load under different working conditions.The normal gear and the defective gear,the low-load defective gear and the defective gear were realized.Comparative experiment of heavyduty defective gears.During the experiment,the gearbox oil and vibration signals were continuously sampled.After the oil sample was processed,the particle counter was used to measure the number and size of abrasive particles with time.At the same time,the Ferrograph was made to observe the distribution of abrasive particles and the morphological characteristics of abrasive particles under a metallographic microscope;The vibration signal is analyzed in the time domain,and the amplitude change characteristics of the gear operation process are obtained.the vibration signal analysis result is combined with the measurement result of the particle counter to explore the relationship between the initial round pit defect,the heavy load condition and the size,number of oil abrasive particles and the change of vibration;Finally,the surface of the experimental gear is sliced,and the development and migration of the surface defects of the tooth surface are observed with the help of metallographic microscope and SEM electron microscope;The wear process evolution of defective gear under heavy load condition is analyzed from different research directions.Scratch defects can easily cause the gear to break,which is not conducive to exploring the changes in the surface topography of the gear.In this paper,the common round pit defects are selected for gear surface defects,and the defect location is near the pitch line where pitting is most likely to occur.Different experimental results show that: Initial defects will cause the gear surface stress to concentrate and the value is several times higher;No obvious signs of wear near the initial round pit defect;The initial round pit defect does not increase the gear vibration amplitude significantly under low load conditions,and the wear condition has little effect,but the gear vibration stability becomes worse;Gear wear and vibration are highly sensitive to high loads,The sudden change of load in the stable wear stage will cause the gear to re-enter the running-in period and produce more large abrasive particles,and the amplitude increases;The initial round hole defect will reduce the stable wear period of the gear and shorten the service life of the gear.In the later stage of the wear,the wear will increase and the amplitude will increase several times and accompanied by a large impact load;Appropriate segmented load is beneficial to reduce wear and extend the service life of gears.