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Experimental Study On Sliding Damage Of Cylindrical Roller Bearings

Posted on:2020-05-15Degree:MasterType:Thesis
Country:ChinaCandidate:Q ZhangFull Text:PDF
GTID:2432330596973098Subject:Mechanical engineering
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As an important support component of the aero-engine,the cylindrical roller bearing’s performance and reliability directly affect the safe operation of the whole equipment.With the development of the aero-engine towards high rotating speed and high thrust-weight(power-weight)ratio,the skid damage has become one of the main incipient failure modes of the cylindrical roller bearing.It has important academic and engineering application value to deeply research the skid damage law of the cylindrical roller bearing.In this paper,firstly,the failure analysis of the cylindrical roller bearing with the occurrence of the skid damage during the service of the aero-engine was carried out,in order to obtain the characteristics of the skid damage of the cylindrical roller bearing.Then,the skid damage of the cylindrical roller bearing was realized by the high-speed rolling bearing test rig,and the dynamic behavior of the skid damage of the cylindrical roller bearing was researched.Then,the microscopic analysis of the skid burn and the skid damage bearings after the test was carried out as well.Finally,the dynamic behavior combined with microscopic analysis of the bearing were to reveal the law of the skid damage of the cylindrical roller bearing.The main conclusions are as follows:(1)Failure analysis of the skid damage of the cylindrical roller bearingThe surface of the inner ring raceway damage zone for the bearing in the service of the aero-engine presents as oxidation wear,and the oxidation degree is higher when closer the surface.The Fe element in the matrix is oxidized to FeO under the local flash temperature.Martensite-to-austenite transformation on the surface of the belt’s surface results in higher content of C element.(2)Research on dynamic behavior of the skid damage of the cylindrical roller bearingThe cylindrical roller bearing has a sudden increase in friction torque,vibration acceleration and temperature when the skid damage happens,and the critical speed of the skid damage is lower under the condition of inadequate lubrication and light load.Reducing the radial load of the cylindrical roller bearing,increasing the speed and lubricating oil viscosity will increase the slipratio of the cage.(3)Microscopic analysis of the skid damage bearing for the testThe longer the running time of the cylindrical roller bearing under the critical speed of the skid damage is,the more serious the wear is.A large number of pits and cracks appear on the damaged surface of the inner ring and roller.The secondary quenching burn occurs in the bearing of the skid burn during the test,and the microstructure of white layer on inner ring is secondary quenched martensite.(4)Research on the law of the skid damage of the cylindrical roller bearingThe cylindrical roller bearing has lower critical speed of the skid damage under the condition of high speed,light load and inadequate lubrication,and the skid damage will accelerate the wear of the cylindrical roller bearing.The mechanism of the skid damage of the cylindrical roller bearing includes oxidation wear,abrasive wear and delamination wear.The large shear stress formed by the skid damage causes the initiation of the crack on the subsurface of the bearing.Subsequently,the crack propagates in longitudinal and transverse direcions under the action of cyclic stress and heat,peeling occurs until the crack and the surface are closed.
Keywords/Search Tags:Cylindrical roller bearing, experimental research, the skid damage, burn, microscopic analysis
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