| 摘要 |
PURPOSE:To measure the axial tension of a bolt having the ruggedness of characteristics having relieve on the top surface of its head part by providing a magnetic sensor constituted by winding primary and secondary coils on an iron core of a U-shape in the cross section on the side face of the head part of the bolt and measuring watt loss. CONSTITUTION:A magnetic sensor 10 constituted by winding primary and secondary coils on an iron core 7 of roughly a U-shape in section is provided in the position 1/3-2/5 the height HH' passing the center of one side face of the head part 5 of a bolt 3 tightening assembled structures 1, 2. The watt loss W in the direction where the iron core direction of a magnetic sensor 10 intersects directly with the HH' is proportional to the axial tension of the bolt and the max. watt loss can be measured. The watt loss W' in the direction coinciding with the HH' is roughly constant with respect to the axial tension. Hence, if W-W' is multiplied by a proportional constant, the axial tension is determined. In spite of the presence of ruggedness of relieved characters or the like in the head part of the bolt, the axial tension is determined by providing the magnetic sensor on the side face of the head of the bolt. |
