| 摘要 |
PROBLEM TO BE SOLVED: To provide a defect detection method related to the securement of high insulation property, in the insulator of a spark plug. SOLUTION: In a pressure resistant vessel 200, a first electrode 300a is disposed in a hollow part of the insulator 110, and second electrodes 300b and 600b are disposed outside the insulator 110. The pressure resistant vessel 200 is sealed with air at a pressure higher than that of the atmosphere. Differential electric potential is generated between the first and the second electrodes 300a and 300b. The leakage current flowing between the first and the second electrodes 300a and 300b is detected. The quality of the insulator 110 is judged, on the basis of determination of whether the leakage current flows or not. Because the pressure resistant vessel 200 is sealed with the air at the pressure higher than that of the atmosphere, spark discharge in the air between the first and the second electrodes 300a and 300b is prevented. Since the leakage current can thereby be detected by setting the differential electric potential between the first and the second electrodes 300a and 300b at a high voltage, it can be detected whether or not the insulating property of the insulator 110 is secured. COPYRIGHT: (C)2004,JPO
|
