Abstract: An engine igniting coil device directly attachable to an igniting plug, wherein both primary and secondary coil bobbins have flangeless ends, the secondary coil bobbin has inwardly protruding ribs for coaxially supporting the flangeless end of the primary coil bobbin mounted therein and the secondary coil bobbin also has protrusions formed at its external wall apart from a high-voltage terminal of the secondary coil wound thereon and is coaxially mounted in a coil case by abutting its protrusions on an inner wall thereof, thus eliminating the possibility of damaging the bobbins by a large thermal stress produced in solidified insulating resin in a coil case by a differential thermal shrinkage in an axial direction and preventing a leakage current from a high-voltage side of the secondary coil bobbin to the coil case through a flange-like connection.

Abstract: An engine igniting coil device adapted to be mounted in a cylindrical bore of an engine and directly connected with an ignition plug therein has a coil case containing an igniting coil assembly and made of conductive magnetic material which is held at the ground potential level, thus preventing a decrease of output factor of the igniting coil of produced magnetic flux when spreading about and passing through a cylinder head of the engine and eliminating the possibility of leakage discharge from a high-voltage portion of the igniting coil assembly to the coil case and the cylinder head.

Abstract: In an engine igniting coil device comprising an ignition coil assembly potted integrally in a coil case by injecting melted insulating resin, a secondary coil is formed on a coil bobbin by bank winding an element wire in layers of wire turns one over another at a certain bank angle in an axial direction on the bobbin and by slope-winding of layers on the end portion of the bobbin by tapering the coil (by reducing the number of layers therein) in the winding direction. This allows setting a dielectric strength of interlayer insulation of the secondary coil according to a potential distribution therebetween, which is secured by forming an insulation resin layer of a reduced thickness between the coil case and the secondary coil of the secondary coil bobbin, thus realizing a compact engine-igniting coil device.

Abstract: An engine ignition coil device which comprises a coil case composed of a first cylindrical case and a second case having a small tubular hole in its center portion and an upper external shoulder at its open end fitted in an open end of the first case to form a closed end of the coil case and an internal unit assembled from a primary side coil bobbin, a secondary-side coil bobbin having a high-voltage terminal holder projecting from a center of its end flange portion, a rod-shaped core, and a high-voltage terminal attached to the high-voltage terminal holder and having a contact for electrically connecting an ignition plug thereto. The internal assembly is mounted in the coil case by inserting the high-voltage terminal holder in the small tubular hole of the secondary case with a tip of the contact projected outwardly therefrom and formed integrally with the coil case by injecting melted insulating resin into the coil case.

Abstract: A plug cap incorporated type ignition coil is provided with a primary coil 20 and a secondary coil 30 inserted in a case 10. After a cushion member 80, a magnet 82, and then a core 40 are inserted in order in a primary coil bobbin 22 of a generally cylindrical bottomed shape, the case 10 is filled with potting resin 70. There is interposed a bottom wall portion of the primary coil bobbin 22 between one end 42 of the core 40 and the potting resin 70. Accordingly, even though stress resulting from the difference in thermal shrinkage between the core 40, the primary coil bobbin 22 and the potting resin 70 is caused, the stress is absorbed by elasticity of the primary coil bobbin 22 and as a result, the potting resin 70 is hard to cause a crack. Also, even though the core is affected by the thermal shrinkage, the magnet 82 is hard to destroy.

Abstract: An engine igniting coil device comprising a coil case with a plurality of coil units disposed therein and integrally potted with insulating resin, which is featured by provision with a coil cover that fits in the coil case and can mount therein high-voltage and low-voltage terminal sockets for the coil units, allowing the assembly of the electrical connections of the coil units in optimal conditions.

Abstract: An engine igniting coil device wherein an I-type core fitted in a hollow portion of a primary coil bobbin and a U-type core are arranged to oppose at their end faces, each other at a specified gap therebetween to form a closed magnetic circuit. The primary coil bobbin with the I-type core has a core holding portion integrally formed thereon for attaching thereto an end portion of the U-type core and the core holding portion also serves as an anti-cracking cover. This cover can accurately determine the positions of both cores and can effectively prevent initiation of cracking in the potting resin injected and cured in the coil case.