| 摘要 |
PURPOSE:To improve detection accuracy and sensitivity by providing magnetical shield bodies on core side faces and maintaining the distance between the shield bodies and the cores at more than twice the distance from the cores up to the steel plate to be detected of its shape. CONSTITUTION:This device obtains the flatness of a rolled steel plate by making use of the fact that there is a fixed proportional relation between the magnetic permeability and internal stress of the rolled steel plate, wherein the detector comprises combining two laminated U-form cores 7, 8 at a right angle, providing an excitation coil 1 at the contact point of the magnets thereof and simultaneously providing pressure detecting coils 2, 3 and gap detecting coils 4, 5. Magnetic shield plates 15 composed of magnetic material are provided near the side faces of the respective detectors constituted in this way so that the leaking magnetic flux emitting from the primary coil 1 is made difficult to reach the other detector. In addition, these are so constituted that the distance B from the shield plates 15 up to the core 8 is maintained more than twice the distance lg between the core 8 and the steel plate 6. |
