超高速微型永磁电机转子强度分析与结构设计

Strength Analysis and Structure Design of Ultra High Speed Micro Permanent Magnet Motor Rotor

超高速微型永磁电机具有能量密度大、运行效率高、便携的优越性能。而永磁材料抗拉强度低,难以承受超高转速下转子巨大的离心力,该文针对超高速微型永磁电机的转子强度问题及结构设计方法进行深入研究。首先,结合微型转子结构特点,建立一种满足多边界类型的转子应力解析模型;其次,重点分析计及机械过盈、永磁体内径、材料特性及环境温升等多影响因素下,超高速微型永磁电机转子结构在不同工况下的应力分布特点及变化规律。此外,基于边界条件及转子结构变化对转子强度影响的规律性分析,设计一款550000r/min超高速转子结构,给出护套厚度、过盈量的选择区间,以及转子应力在不同转速和温度场下的特性评估。最后根据设计方案进行样机研制和实验,实现该转子额定转速稳定运行。

Ultra high speed permanent magnet motor has the advantages of high energy density,high operating efficiency and portable.However,due to the low tensile strength of permanent magnet materials,it is difficult to bear the huge centrifugal force of the rotor under the ultra-high speed.In this paper,the rotor strength problem and the structural design method of the ultra-high speed micro permanent magnet motor were studied in depth.Firstly,combined with the structural characteristics of micro rotor,the analytical model of rotor stress satisfying multi boundary type was established.Secondly,the stress distribution characteristics and variation rules of rotor structures of ultra-high speed micro permanent magnet motor under different working conditions were analyzed,taking into account the mechanical interference,permanent magnet inner diameter,material characteristics and environmental temperature rise and other factors.Then,based on the regular analysis of the influence of boundary conditions and rotor structure changes on rotor strength,a 550000 r/min ultra-high speed rotor structure was designed.The selection range of sleeve thickness,interference value and the characteristic evaluation of rotor stress in different speed and temperature fields were given.Finally,the prototype was developed and tested according to the design scheme.The prototype has achieved 550000 r/min stable operation.