| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a current sensor which has a constitution for detecting a DC magnetic field corresponding to a current to be measured by using a magnetic flux modulated by a Villari effect, comprises a piezoelectric element material as an oscillator having electrodes properly disposed, easily and surely implements a polarization, and is preferably applied to a vehicle application. <P>SOLUTION: The current sensor employs the constitution in which two magnetic material rings are integrated and bonded to the front and back of a piezoelectric element ring 1 and a pickup coil is formed by internally and externally winding a wire material onto an annular region. The electrodes 7, 7 are provided in the front and back of the piezoelectric element ring 1. Two electrode pieces 8 are provided on an outer circumference, and electrically connected to the electrodes 7, 7 so as to form extraction electrodes. A polarization is applied to the piezoelectric element ring 1 in the thickness direction. The piezoelectric element ring 1 is oscillated in the diameter direction by applying a predetermined AC voltage between the electrodes. A mechanical oscillation force is applied to the magnetic material rings. The magnetic flux is modulated by a reverse magnetostrictive effect (the Villari effect). The pickup coil detects a strength of the magnetic field generated by the current to be measured. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
