Research On Dynamic Behavior Of Shaft-Mounted Tilting Mechanism Of Converter

Shaft-mounted tilting mechanism of converter is one of key equipments forcompleting steelmaking production of converter, which is used for stable tilting andaccurate location of body. It is necessary to research the dynamic characteristics oftilting mechanism deeply and master its torsional vibration mechanism in essence,providing theoretical basis for diagnosis early fault of equipment.The context of this paper and main conclusions are as follow.(1) The tilting mechanism is simplified to4branch-12quality system by lumpedmass method based on analyze the structural characteristics of shaft-mounted tiltingmechanism of converter. Torsional vibration dynamic model of system is proposed byLagrange Equation of the second kind. Main parameters of model such as moment ofinertia and torsional stiffness are calculated.(2) Mass matrix and damping matrix of the dynamic model is corrected byadding the factors including moment of inertia of transmission shaft and viscousdamping of bearings lubricating oil, the correction of dynamic differential equation isobtained. The influence of natural characteristic and dynamic characteristics by abovementioned factors is analysed by numerical calculation. Moment of inertia of everytransmission shaft in the tilting mechanism of converter make natural frequency ofsystem decreased and main vibration mode changed and the effect on high naturalfrequency is obvious. Viscous damping of every bearings lubricating oil improve thestationarity of system while the frequency components of torsional vibration is notchanged.(3) Time-varying mesh stiffness is added in the dynamic model of tiltingmechanism for the first time based on analyze the torsional vibration dynamic modelof gear-rotor system. Curve of the time-varying mesh stiffness of the gear on thetrunnion and peripheral driving pinions is obtained according to quadratic parabolic fitting.The adjusting influence of system dynamic characteristics by time-varying meshstiffness is calculated and discussed. Natural frequency of tilting mechanism has thetime varying effect as the same trend as time-varying mesh stiffness while somespecific order natural frequency with the change of mesh stiffness are more sensitivethan others. To decrease the difference value of time-varying mesh stiffness betweensingle-tooth mesh region and double-teeth mesh region has important significance for the stationarity of system.(4) Imbalance character of multi-channel transmission of the tilting mechanismand load balance technology of the gear on the trunnion is discussed. Conception ofload sharing coefficient of planetary gear train is introduced for the first time. Forceequilibrium conditions of central gear on the trunnion and peripheral driving pinionsresult from the accumulated error that is caused by the unbalance of multi-channeltransmission of tilting mechanism is studied. Position deviation of gear on thetrunnion is easier to cause uniform load than peripheral driving intermeshing pinions.