Design of Vibration Isolator of Six Degree-of-freedom by Using Magnet-spring with Energy Source of Permanent Magnet

近年来，伴随着高矫直力、高剩余磁通密度的永磁体的实际应用，磁力轴承、磁流变阻尼器等利用磁力和磁流体控制振动的研究蓬勃发展。这一特性是利用磁体的阻力，将金属弹簧的负弹簧常数与磁体弹簧的非线性特性相结合而得到的。这种磁体是由具有高矫顽力和高剩余磁通密度的稀土磁体(ND-Fe-B)制成的。但由于该系统需要较大的磁铁和复杂的连杆机构，存在装置体积较大、连杆部件热损失大等问题，为此设计了周期性磁场磁路来解决这些问题。该系统将周期性磁场作用下磁路的非线性特性与金属弹簧的线性特性相结合，使其在正常使用条件下弹簧常数处于准零状态时具有线性特性，但总体上为非线性弹簧常数，为了扩大弹簧常数处于准零状态的位移范围，本文通过增加外磁体的极数对电路进行了改进。并利用该特性建立了单摆悬挂系统模型(实验模型)，确定了该模型的振动特性。

In recent years, accompanying the practical use of permanent magnets that have a high coercive force and high residual magnetic flux density, researches about magnetic bearings, MR dampers and so on, which use magnetic force and magnetic fluid to control vibration are flourishing.In this study, the spring characteristic, which is in a quasi-zero state under specific displacement range, has been created. This characteristic has been obtained by combing negative spring constant of metal spring withnon-linear characteristic of magnet-spring using a resisting force of magnet^<1)>. This magnet is made from rare-earth magnets (Nd-Fe-B) that have a high coercive force and high residual magnetic flux density. But, because this system needs large magnets and complicated mechanism of link, it has the point at issue of huger device, heat loss of link part and so on.So a magnet-circuit with a periodic magnetic field has been created to solve these points at issue^<2)>. In this system, the non-linear characteristics of a magnet-circuit with a periodic magnetic field and the linear characteristics of the metal spring are combined to create a spring characteristic which has linear characteristics when the spring constant is in a quasi-zero state under normal conditions of use, but which overall is a non-linear spring constant.In this paper, to expand the displacement range that the spring constant is in quasi-zero state, the circuit was improved by increasing pole of outside magnet. And a pendulum suspension system model using this characteristic (experimental model) was built, and the vibration characteristics of this model were confirmed.