| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance the durability by controlling partial spark in the gap between the outer core and the coil case at least part of the outer surface of which is covered with a semiconductive film. SOLUTION: An ignition coil for internal combustion engines comprises a center core 11, a primary coil 21 wound round a primary coil bobbin 23 disposed round the core 11, a secondary coil 22 wound round a secondary coil bobbin 24 disposed round the core 21, an insulating material-made coil case 25 contg. the core 11 and the coils 21, 22 and filled with an insulating molding agent, and an outer core 12 disposed on the outside of the case 25 with a semiconductive film 14 formed on at least part of the outer surface of the case 25. This film has a surface resistance of 10Ω/cm<2> to 50kΩ/cm<2> . This suppresses the insulation deterioration and prevents the durability from degrading.</p> |
