| 摘要 |
PURPOSE:To detect whether or not a spot welding zone is proper with high detection accuracy by setting a magnetizer and a magneto-electric converting element which detects leak magnetic flux opposite the spot welding zone, and comparing the signal of the magnetoelectric converting element with a preset condition signal. CONSTITUTION:The magnetizer 1 is arranged opposite the spot welding zone B of a body A made of a metallic material to be inspected and the magnetoelectric converting element 4 is arranged between its magnetic poles and assembled in one body. Then when the magnetizer 1 is put close to the body A to be inspected and magnetizes it, magnetic flux 3 travels in parallel to the surface of the body A to be inspected. The magnetic flux 3 leaks in air at the spot weld zone B owing to the difference in magnetic permeability between the metallic material and spot welding zone B of the body A to be inspected and is converted by the magneto-electric converting element 4 into an electric signal, and the output signal 4a is inputted to an electric circuit K. Further, the preset condition signal K1 is inputted to the electric circuit K and compared with the output signal 4a to detect the number of welding spots, whether the position is proper or not, etc. Thus, the leak magnetic flux is detected, so the spot welding zone is accurately detected.
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