| 摘要 |
PURPOSE:To enable accurate pressure detection by dividing both leg end parts of a U-shaped yoke into a center core and guard yokes across it. CONSTITUTION:A bias exciting coil 9 which generates a high DC bias is wound around a U-shaped yoke body part 10 and an alternating exciting coil 11 which generates an alternating magnetic field with a fine amplitude is wound around the leg 4 of the U-shaped yoke. then a search coil 3 which detects the magnetic flux density variation in the center core, i.e. a member to be measured is wound around the center core 12 of the yoke leg 5 and a sensor 13 which monitors a magnetic field applied to the member 7 to be measured is installed in the center between the legs of the yoke. Here, the leg end parts of the yokes 4 and 5 are divided into three and two outside guard yokes 14 prevent a magnetic field produced by the center core 12 from being diffused, thereby establishing a magnetic field having a uniform distribution in a constant direction in the member to be measured. Consequently, the reversible magnetic permeability of the part 15 of the member to be measured where magnetic flux which exits from the center core of one leg and enters the center core of the other leg passes is measured and stress operating there is accurately detected.
|
