| 摘要 |
PURPOSE:To enhance the accuracy of a pressure switch, by providing a metal disc having a recessed part to the part corresponding to the groove part of a soft magnetic body. CONSTITUTION:A soft magnetic body 1 provided with a groove part 1a, the amorphous magnetic alloy disc 2 having magnetostriction arranged so as to cover the groove part 1a and the spacer 3 composed of a non-magnetic plate placed between the soft magnetic body 1 and the disc 2 are provided. These three members constitute a closed magnetic path. Further, the coil 4 wound around the groove part 1a, the metal disc 5 contacting with the disc 2 through the surface different from the soft magnetic body 1 and having a recessed part at the part corresponding to the groove part 1a and a container 6 having a pressure medium introducing through-hole 6a and an O-ring 6b are provided. A detection circuit part 7 takes switching operation corresponding to an inductance value. By providing the disc 5, no stress is applied to the disc 2 up to definite pressure and the steep change in the inductance of the amorphous magnetic alloy to low stress can be utilized in the vicinity of the pressure permitting switching operation and the accuracy of this pressure switch can be enhanced.
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