Obtain an ignition coil in which a magnet is provided at a magnet holding portion which is formed between a first side iron core and a second side iron core, and intervening components which are configured by using a non-magnetic material, are included at facing portions which are provided at end portions of separated surfaces of the first side iron core and separated surfaces of the second side iron core, in a state where the magnet holding portion is formed by using the first side iron core and the second side iron core, and are faced at a surface which is vertical with respect to an axis direction of the side iron cores, and the intervening components have a thickness which is less than a distance between the separated surfaces of the first side iron core and the separated surfaces of the second side iron core.

A method is described for the assembly of a magnetic core for a transformer, with the following steps: Cutting sheet metal blanks from transformer sheet, stacking the sheet metal blanks to form magnetic core segments, placing a permanent magnet at one of the magnetic core segments so that the latter is magnetized by the permanent magnet, formation of the magnetic core by placing the remaining magnetic core segments against the permanent magnet, or against a magnetic core segment already magnetized by the permanent magnet. A magnetic core is also disclosed.

Provided is an ignition coil device for an internal combustion engine, the device including: a plurality of side electrical steel cores which surround a primary coil and a secondary coil, and are divided at a division portion formed at a portion opposing the secondary coil; elastomeric materials respectively covering around the plurality of divided side electrical steel cores; and an insulating case housing the center electrical steel core, the primary coil, the secondary coil, the side electrical steel cores, and the elastomeric materials, and including an insulating resin injected and cured in an internal space thereof, wherein positions of secondary coil-side corner portions of division end portions which are end portions of the side electrical steel cores and the elastomeric materials on the division portion side are set to be different, in an axial direction of the secondary coil, from positions at which flanges of the secondary bobbin are disposed.

A magnetic path is formed of a center core disposed inside a first coil and second coil, a first side core and second side core disposed outside the first coil and second coil and coming into contact with the center core, and a magnet disposed between the first side core and second side core, wherein a shape of a space formed by a portion of contact between the first side core and second side core is a shape that forms an insertion portion of the magnet disposed obliquely with respect to the magnetic path, and voids perpendicular with respect to the magnetic path at either end portion of the magnet.

An ignition coil includes primary and secondary coils, a center core inserted into a center hole of the primary coil and a center hole of the secondary coil, an annular side core that forms a magnetic circuit through which a first magnetic flux A generated by the primary coil by being joined to the center core permeates, and a permanent magnet that is disposed between the center core and the side core and that emits a second magnetic flux B directed opposite to the first magnetic flux A to apply a magnetic bias. The side core includes protruded portions that protrude towards lateral sides of a T-shaped horizontal portion of the center core, and gaps are provided between the lateral sides of the T-shaped horizontal portion of the center core and the protruded portions of the side core.

An internal combustion engine ignition device comprises: a center core; a primary coil wound on the outside of the center core; a secondary coil wound on the outside of the primary coil; a permanent magnet which abuts against one end of the center core and is magnetized in the inverse direction to the direction of a magnetic flux produced by the energization of the primary coil; a side core which is disposed on the outside of the secondary coil with one end abutted against the permanent magnet and the other end abutted against the center core, the side core cooperating with the permanent magnet to form a closed magnetic path; and a heat-resistant and elastic resin covering the side core with an opening at an outer peripheral side. Heat dissipation from the side core to a housing is improved without adversely affecting the dielectric strength voltage of the secondary coil.

An ignition coil includes primary and secondary coils, a center core inserted into a center hole of the primary coil and a center hole of the secondary coil, an annular side core that forms a magnetic circuit through which a first magnetic flux A generated by the primary coil by being joined to the center core permeates, and a permanent magnet that is disposed between the center core and the side core and that emits a second magnetic flux B directed opposite to the first magnetic flux A to apply a magnetic bias. The side core includes protruded portions that protrude towards lateral sides of a T-shaped horizontal portion of the center core, and gaps are provided between the lateral sides of the T-shaped horizontal portion of the center core and the protruded portions of the side core.

Provided is an ignition coil device for an internal combustion engine, the device including: a plurality of side electrical steel cores which surround a primary coil and a secondary coil, and are divided at a division portion formed at a portion opposing the secondary coil; elastomeric materials respectively covering around the plurality of divided side electrical steel cores; and an insulating case housing the center electrical steel core, the primary coil, the secondary coil, the side electrical steel cores, and the elastomeric materials, and including an insulating resin injected and cured in an internal space thereof, wherein positions of secondary coil-side corner portions of division end portions which are end portions of the side electrical steel cores and the elastomeric materials on the division portion side are set to be different, in an axial direction of the secondary coil, from positions at which flanges of the secondary bobbin are disposed.

A magnetic path is formed of a center core disposed inside a first coil and second coil, a first side core and second side core disposed outside the first coil and second coil and coming into contact with the center core, and a magnet disposed between the first side core and second side core, wherein a shape of a space formed by a portion of contact between the first side core and second side core is a shape that forms an insertion portion of the magnet disposed obliquely with respect to the magnetic path, and voids perpendicular with respect to the magnetic path at either end portion of the magnet.

An ignition coil for an internal combustion engine includes: a center core arranged on an inner side of a primary coil and an inner side of a secondary coil; a side core arranged on an outer side of the primary coil and an outer side of the secondary coil, and combined with the center core to form a closed magnetic circuit; one or a plurality of gaps provided between the center core and the side core, or in the side core; and a magnet arranged in each of the one or a plurality of gaps, in which a sum of cross-sectional areas of the respective magnets is set to be three times or more and less than seven times of a cross-sectional area of the center core.