Abstract: A high-strength ignition coil that can reduce stress produced in a coil case and prevent a casting material from being cracked when the ignition coil is mounted on an engine block. A coil case has a mounting flange on an outer surface thereof. A coil assembly is housed in the coil case. A casting material is filled into a gap between the coil case and the coil assembly and gaps which the coil assembly has. A plurality of first guide ribs are provided on an inner wall surface of the coil case or an outer surface of the coil assembly, for positioning the outer surface of the coil assembly with respect to the inner wall surface of the coil case. A limited area in which there is no first guide rib is provided on the inner wall surface of the coil case which faces the mounting flange, or the outer surface of the coil assembly which faces the mounting flange via the inner wall surface of the coil case.

Abstract: An ignition coil is equipped with a sparkplug of an engine. The ignition coil includes a coil portion, a tower portion, and a plug cap. The coil portion includes a coil case accommodating a primary and secondary coils being coaxial with each other. The coil portion has an end connected with the plug cap via the tower portion. The plug cap is press-fitted with the sparkplug. The coil case has an outer periphery from which a flange portion projects radially outward in a flange-projecting direction. The tower cylinder portion has a tower axis substantially in parallel with a coil axis of the primary and secondary coils. The tower axis is offset from the coil axis in a tower-offset direction. The tower-offset direction is substantially the same as the flange-projecting direction.

Abstract: An ignition coil of a dual ignition type that can prevent outputs from becoming unbalanced due to a difference in floating capacitance on wiring that connects secondary output terminals and ignition plugs together, thus realizing balanced outputs. A coil assembly housed in a housing as a coil case has a primary coil and secondary coils disposed concentrically with the primary coil. The secondary coils are comprised of two coils wound in opposite directions with the center of winding width being a boundary. The center of the winding width of the primary coil is shifted from the center of the winding width of the secondary coils by a predetermined width so as to balance outputs from the two secondary coils. A casting material is filled into a gap between the housing and the coil assembly and gaps which the coil assembly has.

Abstract: A high-strength ignition coil that can prevent distortion arising from pin marks formed on a surface of a core and makes it less likely for insulating resin to be cracked. The coil assembly is housed in a coil case. A casting material is filled into a gap between the coil case and the coil assembly and gaps which the coil assembly has. The coil assembly is comprised of a coil pair including a cylindrical primary coil and a secondary coil disposed concentrically with the primary coil, and a core. The core is fitted into a central space of the coil pair and forms a magnetic path. The core is coated with mold resin. Concave portions of pin marks formed on a mold resin coating by removal of core fixing pins when the mold resin coating is formed are filled with mold resin.

Abstract: An ignition coil is equipped with a sparkplug of an engine. The ignition coil includes a coil portion, a tower portion, and a plug cap. The coil portion includes a coil case accommodating a primary and secondary coils being coaxial with each other. The coil portion has an end connected with the plug cap via the tower portion. The plug cap is press-fitted with the sparkplug. The coil case has an outer periphery from which a flange portion projects radially outward in a flange-projecting direction. The tower cylinder portion has a tower axis substantially in parallel with a coil axis of the primary and secondary coils. The tower axis is offset from the coil axis in a tower-offset direction. The tower-offset direction is substantially the same as the flange-projecting direction.

Abstract: A high-strength ignition coil that can prevent distortion arising from pin marks formed on a surface of a core and makes it less likely for insulating resin to be cracked. The coil assembly is housed in a coil case. A casting material is filled into a gap between the coil case and the coil assembly and gaps which the coil assembly has. The coil assembly is comprised of a coil pair including a cylindrical primary coil and a secondary coil disposed concentrically with the primary coil, and a core. The core is fitted into a central space of the coil pair and forms a magnetic path. The core is coated with mold resin. Concave portions of pin marks formed on a mold resin coating by removal of core fixing pins when the mold resin coating is formed are filled with mold resin.

Abstract: A high-strength ignition coil that can reduce stress produced in a coil case and prevent a casting material from being cracked when the ignition coil is mounted on an engine block. A coil case has a mounting flange on an outer surface thereof. A coil assembly is housed in the coil case. A casting material is filled into a gap between the coil case and the coil assembly and gaps which the coil assembly has. A plurality of first guide ribs are provided on an inner wall surface of the coil case or an outer surface of the coil assembly, for positioning the outer surface of the coil assembly with respect to the inner wall surface of the coil case. A limited area in which there is no first guide rib is provided on the inner wall surface of the coil case which faces the mounting flange, or the outer surface of the coil assembly which faces the mounting flange via the inner wall surface of the coil case.

Abstract: An ignition coil of a dual ignition type that can prevent outputs from becoming unbalanced due to a difference in floating capacitance on wiring that connects secondary output terminals and ignition plugs together, thus realizing balanced outputs. A coil assembly housed in a housing as a coil case has a primary coil and secondary coils disposed concentrically with the primary coil. The secondary coils are comprised of two coils wound in opposite directions with the center of winding width being a boundary. The center of the winding width of the primary coil is shifted from the center of the winding width of the secondary coils by a predetermined width so as to balance outputs from the two secondary coils. A casting material is filled into a gap between the housing and the coil assembly and gaps which the coil assembly has.

Abstract: A stick-type ignition coil device has a central core, and primary and secondary windings wound concentrically around the central core in a coil casing. A positioning part is provided in the casing to define the position of the central core. An insulating resin such as epoxy resin is filled in the coil casing for electrical insulation and fixing of components in the coil casing. A thermal stress releasing member, which is less adhesive to and easily peelable from the insulating resin, is provided on the upper surface of the positioning part. The thermal stress releasing member is separated from the insulating resin and allows the positioning member to move with the central core, thereby minimizing cracks which will occur in the insulating resin formed between the central core and the positioning part.

Abstract: A stick-type ignition coil device has a central core, and primary and secondary windings wound concentrically around the central core in a coil casing. A positioning part is provided in the casing to define the position of the central core. An insulating resin such as epoxy resin is filled in the coil casing for electrical insulation and fixing of components in the coil casing. A thermal stress releasing member, which is less adhesive to and easily peelable from the insulating resin, is provided on the upper surface of the positioning part. The thermal stress releasing member is separated from the insulating resin and allows the positioning member to move with the central core, thereby minimizing cracks which will occur in the insulating resin formed between the central core and the positioning part.