CURRENT SENSOR

PROBLEM TO BE SOLVED: To provide a current sensor which adopts a constitution for detecting the DC magnetic field that corresponds to the measurement current by the modulation of the magnetic flux caused by the Villari effect, capable of properly selecting the adhesive agent for bonding, capable of keeping the performance of the adhesive agent in a range of working temperature, and capable of preferably being suitable for on-board use, and so on. SOLUTION: The surface and the rear face of a piezoelectric material ring 1 is sandwiched by a first magnetic material ring 2 and a second magnetic material ring 3 and integrated by bonding so as to constitute a sensor body 4, and a pick up coil 5 is formed by winding the coil, while interlinking with the toroidal body. The surface and the rear face of the piezoelectric material ring 1 are provided with electrode films which are made to polarize in the thickness direction. An adhesive agent for bonding is capable of keeping 40 or higher for D-scale Shore hardness in the range of using temperature, and the film thickness of the adhesive agent is set to 3 μm to 5 μm. For the adhesive agent, the glass transition temperature Tg of which is 140°C higher is used. The hardness of the bonded part can be kept at a prescribed value, and vibration can be transmitted effectively to the side of the magnetic material member. COPYRIGHT: (C)2008,JPO&INPIT