Application Catalog


65 - Analysis of Static Thrust of a Voice Coil Motor <TR>


Overview
Analysis of Static Thrust of a Voice Coil Motor:Overview
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Coreless linear actuators are used for the head drive of electronic packaging machines and precision stages, both of which require high accuracy positioning. Static thrust has a great effect on accurate positioning, since it varies with the translation position of an actuator. Also, static thrust varies with the amount of current, so it is important to obtain the static thrust at each supply current from the analysis. This note presents the use of magnetic field analysis to obtain static thrust characteristics of a voice coil motor at different translation positions and different supply currents.

Static Thrust at Different Translation Positions
Figure 1 shows the static thrust at different translation positions when the supply current is 0.05 A. Figure 2 shows the Lorentz force density distribution of the coil at the translation position of 0 and 1 mm. In Figure 1, the static thrust is maximized at the translation position of 1 mm where the coil is directly beneath each pole. As shown in Figure 2, the Lorentz force density at the translation position of 0 mm is smaller in the circle area compared with the translation position of 1 mm. In addition, the magnetic field at the translation position of 0 mm is smaller in the circle area.
Analysis of Static Thrust of a Voice Coil Motor:Static Thrust at Different Translation Positions
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Analysis of Static Thrust of a Voice Coil Motor:Static Thrust at Different Translation Positions
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Magnetic Field Distribution
Analysis of Static Thrust of a Voice Coil Motor:Magnetic Field Distribution
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Figure 3 shows the magnetic field distribution at the translation position of 0 and 1 mm. The magnetic field at the translation position of 0 mm is weaker in the circle area, and also the direction of the magnetic field is not perpendicular to the translation direction. Since the direction and amount of the current flowing in the coil are constant, the static force (Lorentz force) is determined by the strength and direction of the magnetic field. So, the static force becomes smaller due to the magnetic field distribution of the coil.

Static Thrust at Different Supply Currents
Figure 4 shows the static thrust at different supply currents. Static thrust increases linearly with the increase of supply current. The thrust constant is 6 N/A according to the slope of the graph. it is certain that the static thrust can be controlled by the amount of supply current. Analysis of Static Thrust of a Voice Coil Motor:Static Thrust at Different Supply Currents
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Updated: 2011-01-17



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