Patent ID: 7753038

Claim:
An ignition coil for a sparkplug of an engine, the ignition coil comprising: a coil main body including a coil case accommodating a primary coil and a secondary coil; and a plug mount portion provided to a high voltage end of the coil main body on a high voltage side, wherein the coil case has an inner gap charged with an infilling resin, the plug mount portion and the coil main body are inserted into a plughole of the engine, the plug mount portion has a cap mount portion in a substantially cylindrical shape extending from a primary spool of the primary coil or the coil case, the cap mount portion is connected with a plug cap, which is formed of rubber, having a fitting hole into which an insulator portion of the sparkplug is inserted together with a high voltage terminal and a coil spring, the high voltage terminal is electrically conductive with a high voltage winding end of a winding of the secondary coil on the high voltage side, the coil spring electrically conducts the high voltage terminal with a terminal portion of a tip end of the insulator portion of the sparkplug, the plug cap has a circumferential mount portion, which is in a substantially cylindrical shape, attached to an outer circumferential periphery of the cap mount portion, the cap mount portion has a substantially annular space communicating with the inner gap in the coil case, the substantially annular space is charged with the infilling resin, and the circumferential mount portion has a low voltage end on a low voltage side, and the substantially annular space has a high voltage end located on the high voltage side with respect to the low voltage end of the circumferential mount portion.