| Wheel set bearing is one of the key components of the running gear of railway wagons,which will directly affect the safety of wagons.In the working process,railway wagons often operate under variable speed and load conditions such as starting,stopping,turning,etc.,which will change the interaction between the internal parts of wheel set bearings,cause changes in their dynamic characteristics,and then affect the service performance and life of bearings.At present,the dynamic influence mechanism of double-row tapered roller bearings used for wheel set bearings of railway wagons under variable working conditions is not clear,so it is necessary to carry out dynamic modeling of wheel set bearings under variable working conditions and analysis of their dynamic characteristics combined with the running conditions of railway wagons.In this paper,the 353130 B double row tapered roller bearing for railway wagons is taken as the research object,considering the flexibility of the cage,and a rigid-flexible coupling multi body dynamic model of the double row tapered roller bearing is established based on the ADAMS platform.The dynamic characteristics of the bearing under variable speed and load conditions are analyzed,and the influence of start stop conditions,variable axial load,periodic excitation,and impact on the dynamic characteristics of the bearing is obtained.The main research content is as follows:(1)Based on the theory of rigid-flexible coupling,a rigid-flexible coupling multi body dynamics model of double row tapered roller bearings is established,taking into account the flexibility of the cage,the influence of contact stiffness and oil film stiffness.The bearing dynamic characteristics under typical working conditions are analyzed and compared with the results of classical Hertz formula to verify the accuracy of the model.(2)On the basis of the established rigid-flexible coupling dynamic model of wheel set bearing,the influence of variable speed on bearing dynamics characteristics is studied,and the changing rules of bearing motion during different speed,starting and stopping are revealed.The results show that with the change of rotational speed,the dynamic characteristics of the cage and inner ring change significantly.During the start and stop process,the cage equivalent force and vibration acceleration change violently.(3)Aiming at the bearing dynamics problem of turning and other variable axial loads,the influence of variable axial load on bearing dynamic characteristics based on the dynamic model is conducted,and the influence laws of variable axial load and alternating axial load on bearing dynamics are obtained.The results show that the influence of variable axial load and alternating axial load on the axial displacement of the cage is relatively obvious,and with the change of the maximum axial load,the equivalent force of the cage and the trajectory of the center of mass change,which has a significant impact on the range of motion of the inner circle center of mass and the contact load between the roller and the inner and outer rings.(4)Aiming at bearing variable radial load dynamics problem caused by wheel-rail vertical load variation,bearing dynamic characteristics analysis under periodic excitation and impact load caused by wheel fault are carried out.The results show that when the bearing is subjected to periodic excitation and impact load,the radial displacement curve of the inner ring presents periodic changes in time domain,and the displacement curve in frequency domain changes in frequency doubling.With the increase of polygon amplitude and wheel flat length,the vibration response of the inner ring,roller and outer ring increases.In this paper,a rigid-flexible coupling dynamic model of railway wagons wheel set bearing with cage flexibility is established,and the influence law of variable speed and load on bearing dynamic characteristics is revealed,which is of great significance for improving the dynamic performance of railway wagons wheel set bearing. |
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