Dynamic Analysis of A New Linear Actuator Using 3-D Finite Element Method

Abstract

This paper presents the dynamic analysis method for a new linear actuator using a DC motor. Fig. 1 shows the basic construction of the actuator. It mainly consists of a DC motor, two magnets with yokes, resonance springs, shaft, and bearings. A couple of multi-polarized permanent magnets of a rotor and a linear motion armature are opposite together. The rotor is directly connected to the shaft of a DC motor, and the mover is connected to the resonance spring. The operating principle of this actuator is that the armature linearly moves in direction of z-axis as the attractive or repulsive force acts on the armature according to the rotation of the rotor. It reciprocates twice while the rotor travels around when you use a couple of four polarized permanent magnets as shown in Fig. 2.In the proposed dynamic analysis method, the magnetic field is coupled with the eqations of rotation and linear motion, and an automesh modification method is developed to consider both motion.The dynamic charasteristics are computed when the rotation Table 1 shows the analyzed conditions. Fig. 3 shows the calculated time variation of the amplitude of the armature. As shown, it is found that the amplitude increases as time goes on, and it becomes stable with the amplitude of about 1.0 mm. Fig. 4 shows the characteristics of amplitude versus frequency. It is found that the amplitude of the actuator increases as the operating frequency increases because this actuator has a resonance frequency of about 240 Hz theoretically. The calculated results agree well with measured one at the frequency of 216.1 and 222.8 Hz. As the results, the validity of this method is confirmed. Yuya Hasegawa * * MemberTadashi Yamaguchi * * * MemberYoshihiro Kawase * * * Senior MemberKoichi Shamoto * * * Non-memberHiroyuki Kodama * * * Non-memberThis paper presents the coupled analysis method for a new structured linear actuator that can convert the rotation into linear actuation by the attractive and repulsive force of permanent magnets. In this method, the 3-D finite element mesh modification method for multi-motion analysis is taken into consideration. The effectiveness of this method is verified through the comparison with the measured results.

Electromagnetic and Mechanical Performance of Direct and Indirectly Liquid-cooled Coreless Linear Motors with Multi-layer Coils

“…Therefore, direct-contact cooling methods are preferred in coreless linear motors, resulting in heat transfer without large mass and volume penalties. Furthermore, in these motor configurations stresses due to elevated temperature distributions and magnetic force production are not investigated whereas in (7)- (11) it was shown that significant levels of stress can be present in coreless and iron-cored magnetic devices. The analysis of these stresses is often performed on a simplified geometry, either in 2-D (7) (8) (10) or in 3-D on small segments (9) (11) .…”