| In order to implement the strategy of a manufacturing power strategy,the Chinese government has proposed the first ten-year action plan of "Made in China 2025".As the core equipment of the manufacturing industry,modern rotating machinery has the development needs of high speed,precision and intelligence.This has higher requirements for the dynamic balance accuracy and speed of the rotating machinery rotor system,and it is necessary to study the dynamic balance principle and automatic balance method of rotating machinery.At present,the most commonly used dynamic balance method in the actual operation of the factory is the trial-and-weight method,that is,the dynamic balance is performed by repeatedly trying and increasing the trial weight.This method needs to be shut down,economic loss is large,and the workload is large,and the efficiency is low.When the imbalance occurs again,it needs to be shut down again for operation.Engineering requirements have promoted the development of online automatic balancing technology.This technology can measure the imbalance of the rotor in real time through the sensor during the operation of the equipment,and when the imbalance exceeds the limit,it will automatically issue instructions to the actuator to make the corresponding action(change the mass distribution or apply electromagnetic force),which is effective Reduce the vibration of the rotor due to dynamic imbalance.The online automatic balancing technology can reduce the vibration of the equipment in real time,reduce the downtime of the equipment,and ensure the safe and stable long-term operation of the equipment.Electromagnetic ring(EMR)automatic balancing actuator has the advantages of no complicated auxiliary system,compact structure,fast response speed,high balance accuracy and long service life.However,the moving ring and the static ring in the traditional electromagnetic slip ring balance device adopt a two-piece structure.The moving ring and the static ring need to be installed separately during the installation process,and the gap between the moving and static rings must be about 0.5mm.Installation and use difficult.The integrated electromagnetic slip ring type automatic balance structure.Although there is no need to adjust the dynamic and static ring gap during installation,it greatly reduces the installation difficulty of this type of product,and is small in size and compact in structure.However,due to its axial excitation structure,when the magnetic force of the excitation ring on both sides of the counterweight plate differs too much due to assembly errors,etc.,the counterweight plate may deflect and rub against the excitation ring.The process interferes.Although increasing the gap between the excitation ring and the counterweight disc can avoid friction,it will reduce the electromagnetic efficiency of the actuator and require a larger drive voltage,which is not conducive to practical applications.Moreover,this type of actuator is usually driven by a full permanent magnet,and the self-locking force generates too much resistance during the stepping process of the counterweight disc,which also affects the driving efficiency of the actuator.Based on the above problems,the main research work of this paper is as follows:(1)On the basis of the integrated electromagnetic slip ring automatic balance structure,the actuator axial excitation structure is improved to a radial excitation structure,which solves the problem of deflection and friction with the excitation ring during the rotation of the counterweight.Under the premise of ensuring a small gap,the operating stability and electromagnetic drive efficiency of the actuator are effectively improved.In addition,the radial structure can greatly reduce the axial size of the overall structure compared to the original axial structure,which is more convenient for the integration of the actuator and the spindle of the machine tool.(2)The permanent magnet and soft iron combined drive mode is adopted.The original integrated electromagnetic ring type automatic balance actuator counterweight plate adopts a full permanent magnet structure,which is not conducive to the improvement of actuator drive efficiency.Therefore,it is considered to replace part of the permanent magnets on the original counterweight disk with soft iron.On the premise that the self-locking force meets the demand,the driving resistance is effectively reduced,and the electromagnetic driving efficiency of the balance actuator is increased.(3)Use Maxwell 2D and 3D to electromagnetically simulate the magnetic circuit and the three-dimensional overall model of the actuator section.Analyze the magnetic induction intensity distribution and magnetic saturation state of the magnetic circuit in the axial section of the actuator,and the magnetic induction intensity distribution in the overall structure.By setting different actuator structure parameters and performing multiple sets of two-dimensional electromagnetic simulations,reasonable actuator-related design parameters were obtained.Calculate the changes of key mechanical parameters such as actuator self-locking torque and driving torque under different structural parameters of the actuator.Study the changes of various mechanical parameters during the stepping process of the actuator to ensure that the actuator meets the needs of actual work.(4)Design and manufacture a prototype of the radial excitation structure actuator,and use the trial weight method to measure the self-locking torque of the actuator.Design the actuator control circuit,use LabVIEW to design the actuator measurement and control program,and measure the static minimum drive voltage of the actuator.Build a high-end machine tool automatic balance simulation experiment table,and install the actuator on one end of the machine tool spindle.Test the balance performance of the actuator at the normal working speed of the spindle,and the driving efficiency at different speeds to verify the vibration suppression ability of the actuator on the test bench. |
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