Patent attributes
An ignition coil for an internal combustion engine has a first housing, a second housing, a holder, an insulating resin and a crack extension restrictor. The first housing encloses a center core, a primary coil and a secondary coil. The second housing has an install portion and a cylinder-shaped fitting portion fitted to a top cylindrical portion of the first housing. The holder is laid over top ends of the primary and secondary coils. The insulating resin is charged in an annular cavity defined at least by uppermost portions of the primary and secondary coils, the fitting portion and the holder and in contact with the fitting portion. The crack extension restrictor is formed by a part of the fitting portion and a part of the holder and disposed above the fitting faces of the fitting portion and the top end portion.
