| 摘要 |
PURPOSE:To increase the measuring accuracy of a pressure sensor, by forming a magnetic circuit comprising a yoke made of an amorphous metallic soft magentic matter having the small magnetic distortion and high magnetic permeability and a pressure holding plate consisting of an amorphous metallic soft magnetic matter having the large magnetic distortion and then detecting the pressure applied to the pressure holding plate. CONSTITUTION:A pressure sensor 1 has a casing 3 having an inlet port 2. The aperture part of the casing 3 is sealed by a cover 4, and a magnetic shielding matter 5 is fixed by a hollow holder 6. A detection coil 10 is wound round a bobbin 8 made of a nonmagnetic matter having a center hole 9. A yoke 11 having a tongue piece 13 and a circular part 12 is made of an amorphous metallic soft magnetic matter having the small magnetic distortion and high magnetic permeability. A magnetic circuit is formed between the yoke 11 and a pressure holding plate 14 made of an amorphous metallic soft magnetic matter having the large magnetic distortion. When the tensile stress is applied to the plate 14, the magnetic permeability of the plate 14 increases. Then the fluid pressure acting on the plate 14 is measured with high accuracy from the time during which the voltage is applied to the coil 10 and then the current reaches a prescribed level. |
