Design And Analysis Of Dynamic Characteristics Of Permanent Magnet Synchronous Motorized Spindle

With development and application of the technology of high-speed machining used widely, high-speed NC machine tool is increasingly demanded in wide spread field of industry. With the development of world economy, competition is overheating between enterprises. In order to promote progress of enterprise economy and technology, respond market rapidly, it is urgent to research and develop the high-speed NC machine tool. Motorized spindle is the core component of high-speed machine tool. While, permanent magnet synchronous motorize spindle (PMSMS) has advantages of low vibration, low noise, high accuracy, good stability and so on. It is more and more valued by people. Therefore, it is very important to conduct optimization design and dynamic analysis on PMSMS to enhance performance of high precision NC machine tool.This paper introduces the design of 14kW permanent magnet synchronous motorized spindle. The design includes selection of bearing types, calculation of bearing preloaded force and stiffness, selection of the optimum span, the determination of seal form and cooling lubrication way of spindle unit, computing of dynamic balance of rotating spindle assembly,analysis of temperature field, etc.The dynamic characteristics of motorized spindle have a great influence on machining precision and stability. Therefore, it is very important to analyze the dynamic characteristics of PMSMS. This research section includes establishing the FEM model, doing modal analysis of main structure parts of PMSMS by ANSYS software. The rule of effect of temperature field and stress variable on elasticity and stiffness of the spindle is determined. Targeted is proposed to improve the method of dynamic characteristic of PMSMS to provide references for design and improvement of PMSMS.This paper completes magnet design of PMSMS. Radial and tangential magnet flux density and magnet force are analyzed by FEM. Radial unbalanced magnetic pulls (UMP) are calculated. The main factors affecting UMP are investigated. The critical speeds of PMSMS including UMP are obtained. Motor torque ripple is resulted from motor tangential flux density. The instantaneous torque ripple are got basing on the analysis of magnetic field of motor. Through the analysis of magnitude and frequency spectrum of the magnetic field of motor, main components influencing torque ripple are found. Effective methods of suppress motor radial magnetic pull and torque ripple are proposed.