Research On The Dynamic Characteristics Of The Spindle Rotor System Of The Time-frequency Variable High-speed Winding Head

The spindle rotor system of winding head is the core part of the winding machine of chemical fiber spinning equipment.Its dynamic characteristics affect the whole quality of the winding machine.The winding head spindle rotor system has the characteristics of cantilever,slender shaft and thin wall in structure.And in the process of winding,the mass and speed parameters of the subsystem change time.In addition,the working speed of the rotor system crosses the multi-order critical speed,which causes violent resonance,resulting in accelerated wear and destruction of the parts of the winding machine,causing serious accidents.In this paper,the spindle rotor system of the winding head is taken as the research object,and the dynamic characteristics of the time-frequency variable rotor system are analyzed,which provides certain reference and reference value for improving the quality of the winding machine.Firstly,according to the structure characteristics and working principle of the spindle rotor system of a certain type of winding head,the structure is simplified,and the dynamics model of rotor-bearing-casing coupling is established.In order to verify the correctness of the dynamic model,the first six natural frequencies and modes of vibration of the key parts of the winding head,supporting sleeve,drive shaft and sleeve were calculated based on the finite element method.It is consistent with the experimental results obtained by Data Physics modal testing system,which lays a foundation for subsequent numerical simulation calculation.On this basis,the static and dynamic stiffness of the support sleeve is calculated.The results show that the static and dynamic stiffness of the support sleeve is relatively close,but the dynamic stiffness has a great mutation around 93 Hz.By calculating the critical speed of a single rotating part,it is found that the critical speed is sensitive to the change of supporting stiffness.Then,according to the dynamic model of the whole machine,the first three critical speeds of the spindle rotor system of the winding head are calculated,which are 2173 r/min,1198 r/min and 17925 r/min respectively,and the second critical speed is within the working range of the winding head.The variation of critical speed with support stiffness of spindle rotor system with winding head is calculated.The results show that the displacement amplitude is relatively small when the speed is properly increased and the critical speed is quickly passed.Then,the influence of sliding bearing structural parameters on the stability of the rotor subsystem was discussed,and the dynamic model of the bearing-rotor system was established considering the radius clearance.The Reynolds equation was solved based on the finite difference method to obtain the bearing oil film pressure distribution and static and dynamic characteristic coefficients under different radius clearance and loads.Then,the center trajectory and time domain response of the bearing-rotor system with different radius clearances are solved.The results show that adjusting the radius clearances of the bearing can effectively reduce the vibration of the rotor system due to unbalance.Finally,on the basis of a dynamic model of the whole machine,consider the package quality of cake,it is defined as the time function,using Newmark-beta numerical integral method,to solve the existence only initial rough measure and package quality slow change of time-frequency dynamics response,by analyzing the axis trajectory,the time domain response and frequency response curve,etc.The calculation results,It is found that the rotor system is sensitive to the slow change of excitation amplitude caused by bad coiling,and a new frequency component appears.The above research results can provide theoretical support for the dynamic design and fault identification of the rotor system with coiling head spindle.