Abstract: An ignition coil has a connector electrically connected to an external circuit, an igniter for accommodating a switching element adapted to cause a current supplied from the connector to be intermittent, a primary coil portion for generating a predetermined voltage by the intermittent current, a secondary coil portion for stepping up the generated voltage and applying the resulting voltage to an ignition plug, and a resin insulating material which hardens in between the primary coil portion and the secondary coil portion to ensure insulation between the primary coil portion and the secondary coil portion. An outer shell of the igniter is formed of the resin insulating material.

Abstract: A small-diameter ignition coil includes a center core, a primary coil, a secondary coil, and a thin film tube. The primary and secondary coils are arranged on an outer circumferential side with respect to the center core. The thin film tube has a cylindrical shape. The thin film tube is arranged on an outer circumferential side with respect to one of the primary coil and the secondary coil that is arranged on an outer circumferential side with respect to the other of the primary coil and the secondary coil. The thin film tube is thermally resistive and electrically insulative. The thin film tube has wall thickness that is equal to or less than 0.35 mm. An electrically insulative resin is filled in a gap formed between the thin film tube and one of the primary coil and the secondary coil, which is radially adjacent to the thin film tube.

Abstract: A resin composition includes a thermosetting resin and a filler dispersed in the thermosetting resin. A filler particle size curve represents a small-diameter peak, a large-diameter peak having a higher frequency than that of the small-diameter peak, and a valley which is positioned between the small-diameter peak and the large-diameter peak and has a lower frequency than that of the small-diameter peak. An ignition coil device allows the resin composition to penetrate into gaps between turns of a coil wire.

Abstract: An ignition coil has a connector electrically connected to an external circuit, an igniter for accommodating a switching element adapted to cause a current supplied from the connector to be intermittent, a primary coil portion for generating a predetermined voltage by the intermittent current, a secondary coil portion for stepping up the generated voltage and applying the resulting voltage to an ignition plug, and a resin insulating material which hardens in between the primary coil portion and the secondary coil portion to ensure insulation between the primary coil portion and the secondary coil portion. An outer shell of the igniter is formed of the resin insulating material.

Abstract: A small-diameter ignition coil includes a center core, a primary coil, a secondary coil, and a thin film tube. The primary and secondary coils are arranged on an outer circumferential side with respect to the center core. The thin film tube has a cylindrical shape. The thin film tube is arranged on an outer circumferential side with respect to one of the primary coil and the secondary coil that is arranged on an outer circumferential side with respect to the other of the primary coil and the secondary coil. The thin film tube is thermally resistive and electrically insulative. The thin film tube has wall thickness that is equal to or less than 0.35 mm. An electrically insulative resin is filled in a gap formed between the thin film tube and one of the primary coil and the secondary coil, which is radially adjacent to the thin film tube.

Abstract: In a stick coil, there is disclosed an ignition coil for an internal combustion engine which can prevent a crack (a collar leak) from being generated due to a thermal stress. In this ignition coil, the structure is made such that a size (L) of a portion which is in parallel to an axial direction of a primary spool (121) in a projection portion (121b) is larger than a size (T) of a portion which is in parallel to an orthogonal direction to the axial direction of the primary spool (121). Accordingly, a frontal projected area of the projection portion (121b) as seen from a flowing direction of a resin becomes small, a resin flow is hard to get out of order at a time when the resin flows through a portion corresponding to the projection portion (121b) at the forming time, and a convoluted void and a weld are hard to be generated.

Abstract: A resin composition includes a thermosetting resin and a filler dispersed in the thermosetting resin. A filler particle size curve represents a small-diameter peak, a large-diameter peak having a higher frequency than that of the small-diameter peak, and a valley which is positioned between the small-diameter peak and the large-diameter peak and has a lower frequency than that of the small-diameter peak. An ignition coil device allows the resin composition to penetrate into gaps between turns of a coil wire.

Abstract: An ignition coil has a connector electrically connected to an external circuit, an igniter for accommodating a switching element adapted to cause a current supplied from the connector to be intermittent, a primary coil portion for generating a predetermined voltage by the intermittent current, a secondary coil portion for stepping up the generated voltage and applying the resulting voltage to an ignition plug, and a resin insulating material which hardens in between the primary coil portion and the secondary coil portion to ensure insulation between the primary coil portion and the secondary coil portion. An outer shell of the igniter is formed of the resin insulating material.

Abstract: An ignition coil has an outer coil unit, an inner coil unit, a coil case in which the outer and inner coil units are housed and a tower case accommodating lower parts of outer and inner spools. The outer spool is made of resin material whose bonding strength to resin insulating material, with which the tower case is filled, is weak. An axial leading end of the outer spool is positioned axially away from a reference position by a distance equal to or shorter than 60% of a reference length or by a distance equal to or longer than 90% of the reference length. With this ignition coil, cracks are suppressed on the resin insulating material opposed to the axial leading end of the outer spool otherwise caused by thermal stress.

Abstract: An ignition coil (1) having a case (2), a core (22) installed in the case, a primary spool (25) disposed substantially coaxially around an outer circumference of the core within the case, a primary coil (26) comprising a wire wound around the primary spool, a secondary spool (23) disposed substantially coaxially around the outer circumference of the core within the case, a secondary coil (24) comprising a wire wound around the secondary spool and a resin insulating material (5) filled within the case, the ignition coil being characterized in that the spool of the primary and the secondary spools which is disposed between the secondary coil and the core and/or which is disposed between the secondary coil and the primary coil comprises a base resin having an adhesive strength to the resin insulating material which is less than that provided by polybutylene terephthalate and an insulation breakdown voltage which exceeds that provided by polyphenylene sulfide.

Abstract: A thin injection molded article is composed of a composite resin material of organic clay 2 dispersed in a polymer 1. The polymer comprises a blend of polyphenylene oxide and a butadiene-styrene copolymer. The relationship between the maximum flow length L of the composite resin material in the thin injection molded article and the average thickness t of the thin injection molded articles satisfies the inequality: L/t≧70.

Abstract: In a stick coil, there is disclosed an ignition coil for an internal combustion engine which can prevent a crack (a collar leak) from being generated due to a thermal stress. In this ignition coil, the structure is made such that a size (L) of a portion which is in parallel to an axial direction of a primary spool (121) in a projection portion (121b) is larger than a size (T) of a portion which is in parallel to an orthogonal direction to the axial direction of the primary spool (121). Accordingly, a frontal projected area of the projection portion (121b) as seen from a flowing direction of a resin becomes small, a resin flow is hard to get out of order at a time when the resin flows through a portion corresponding to the projection portion (121b) at the forming time, and a convoluted void and a weld are hard to be generated.

Abstract: An ignition coil according to the invention is an ignition coil having a case and a coil portion accommodated in the case. The case comprises a base resin whose dielectric breakdown voltage exceeds that of polyphenylene sulfide and whose spiral flow length exceeds that of polybutyrene terphthalate. As the base resin has a high fluidity, there is only a limited risk that a defect such as a weld line is caused when molding a thin case. In addition, while the thickness of the case and the electrical insulation properties are in proportion to each other, the case comprising the base resin can ensure sufficient electrical insulation properties even if the case is formed thin.

Abstract: An ignition coil has a connector electrically connected to an external circuit, an igniter for accommodating a switching element adapted to cause a current supplied from the connector to be intermittent, a primary coil portion for generating a predetermined voltage by the intermittent current, a secondary coil portion for stepping up the generated voltage and applying the resulting voltage to an ignition plug, and a resin insulating material which hardens in between the primary coil portion and the secondary coil portion to ensure insulation between the primary coil portion and the secondary coil portion. An outer shell of the igniter is formed of the resin insulating material.

Abstract: An ignition coil includes a housing which contains a central core portion, an inner spool having a first winding, and an outer spool having a second winding. The inner spool extends outward of the central core portion. The outer spool extends outward of the inner spool. A locating member includes a locating rib adjacent to an upper portion of the central core portion. The locating rib is in a gap between the inner spool and the central core portion, and locates the inner spool and the central core portion relative to each other. Insulating resin injected into the housing provides insulation among parts in the housing. At least one of the inner spool and the locating member has a void-escape passage which connects the gap and an outside of the inner spool with each other, and which allows a void to escape from the injected insulating resin in the gap.

Abstract: An ignition coil (1) having a case (2), a core (22) installed in the case, a primary spool (25) disposed substantially coaxially around an outer circumference of the core within the case, a primary coil (26) comprising a wire wound around the primary spool, a secondary spool (23) disposed substantially coaxially around the outer circumference of the core within the case, a secondary coil (24) comprising a wire wound around the secondary spool and a resin insulating material (5) filled within the case, the ignition coil being characterized in that the spool of the primary and the secondary spools which is disposed between the secondary coil and the core and/or which is disposed between the secondary coil and the primary coil comprises a base resin having an adhesive strength to the resin insulating material which is less than that provided by polybutylene terephthalate and an insulation breakdown voltage which exceeds that provided by polyphenylene sulfide.

Abstract: An ignition coil includes a center core, a primary coil a secondary coil, a coil housing, a tower housing disposed under the coil housing, and a high tension terminal disposed inside the tower housing. The high tension terminal has an upper flange disposed at a first circumferential gap opposite the inside surface of the tower housing and a middle barrel disposed at a second circumferential gap opposite the inside surface of the coil housing. The first circumferential gap is made smaller than the second circumferential gap. The tower housing or the upper flange has a void-purging passage for purging air from the insulation resinous members when filled in the coil housing.

Abstract: An ignition coil includes an insulating resin, a primary coil, and a secondary coil. The primary coil is formed by winding a primary wire coated with a primary coating, and is disposed in the insulating resin. The secondary coil is formed by winding a secondary wire coated with a secondary coating, and is disposed in the insulating resin to be concentric with the primary coil. A glass transition temperature of the insulating resin is set to 130° C. or below, and a glass transition temperature of the secondary coating is set to 150° C. or above. Therefore, thermal stress between the insulating resin and parts adhered to the insulating resin in the ignition coil can be effectively reduced, and the life of the ignition coil with cooling/heating cycle can be elongated.

Abstract: In an ignition coil having an outer coil unit, an inner coil unit, a coil case in which the outer and inner coil units are housed and a tower case accommodating lower parts of outer and inner spools, the outer spool is made of resin material whose bonding strength to resin insulating material, with which the tower case is filled, is weak and an axial leading end of the outer spool is positioned axially away from a reference position by a distance equal to or shorter than 60% of a reference length or by a distance equal to or longer than 90% of the reference length. With this ignition coil, cracks hardly occur on the resin insulating material opposed to the axial leading end of the outer spool by thermal stress.

Abstract: An ignition coil includes a center core, a primary coil a secondary coil, a coil housing, a tower housing disposed under the coil housing, and a high tension terminal disposed inside the tower housing. The high tension terminal has an upper flange disposed at a first circumferential gap opposite the inside surface of the tower housing and a middle barrel disposed at a second circumnferential gap opposite the inside surface of the coil housing. The first circumferential gap is made smaller than the second circumferential gap. The tower housing or the upper flange has a void-purging passage for purging air from the insulation resinous members when filled in the coil housing.