Patent ID: 6980073
Filing Date: 2005-12-27
Classification: H01F

Abstract:
1. An ignition coil comprising; a housing; a rod-shaped center core arranged substantially at the center within the housing; a thermal stress relaxing member covering the outer circumferential surface of the center core; a cylindrical spool arranged on the outer circumferential side of the thermal stress relaxing member with a gap therebetween; and a resin insulating material with which the gap is filled and which hardens and provides an electrical insulation between the center core and a coil wound around the cylindrical spool; wherein the thermal stress relaxing member is wound around the center core; and the thickness of the thermal stress relaxing member is set to a thickness so that the thermal stress, which is caused by the thermal deformation of the center core and is applied to the resin insulating material, is reduced and reaches a saturation value thereof.