电织针永磁阵列内的静磁场分布及结构刚度分析

Static magnetic field and structure rigidity analysis for permanent magnet matrix in electric knitting needle

针对电织针永磁阵列由于磁体间吸合力不平衡引发的结构刚度问题,重点研究了电织针永磁阵列内的静磁场分布状况,推导了每列永磁体薄片所承受的不平衡吸合力的表达式,给出了永磁体的挠曲变形。分析结果表明,永磁体占空比α主要影响到气隙磁场的谐波分量的多少;永磁体厚度系数β和气隙厚度系数γ主要影响气隙磁场的大小;织针片数n在大于10的情况下,对气隙磁场以及永磁体最大不平衡力没有显著性影响。为提高电织针设计中的永磁阵列结构刚度,应尽可能缩短永磁体薄片的长度,增大永磁体的厚度,永磁阵列几何参数选择α在0.6～0.9之间,β在0.07～0.1之间,γ在0.5左右。

Regarding the structural rigidity problem caused by unbalanced magnetic force that applied on each magnet piece,the internal static magnetic field inside the permanent magnet matrix in electric knitting needle was researched.Analytical equations of unbalanced magnetic force were derived upon each column of magnets,which decided the maximum deflection.It is shown that the magnetic duty ratio α mainly affects the percentage of harmonic magnetic waves in the air,and the magnet thickness ratio β and air clearance ratio γ mainly affects the magnitude of the magnetic field.The number of moving-coil-sliders n has very little effects both on the magnetic field magnitude in the air and the maximum unbalance magnetic force on each magnet piece when n 10.In order to improve the magnet matrix rigidity in electronic knitting needle design,shorter and thicker magnet piece is preferred,and the optimal geometric matrix parameters should be α ∈[0.6,0.9],β ∈[0.07,0.1],and γ be around 0.5.