JPS5754307A - Ignition coil for internal combustion engine - Google Patents

Abstract

PURPOSE:To enable miniaturizing the ignition coil and to improve the withstand voltage performance thereof by providing the secondary coil bobbin with a stopper part for the outgoing wire of the secondary coil and further by providing projections for preventing exfoliation of cast epoxy resin from the secondary coil bobbin. CONSTITUTION:On the secondary bobbin 7 made of synthetic resin, a plurality of grooves are formed with flanges 8 arranged in the direction of the axis of the bobbin and the secondary coil 10 is wound along the groove, while the primary coil is wound along the groove, while the primary coil is wound round the primary bobbin arranged in such a manner that the flange thereof contacts with the inner circumference of the secondary bobbin. At the flange of the secondary bobbin 7, located at the end on the starting side of the secondary coil 10, a groove 17 for drawing out the starting end of the coil 10 is provided, while on both sides thereof the projections 18, 19 and grooves 20, 21 are provided. The starting end 22 of the secondary coil is drawn out from between the projections 18 and 19 of the groove 17, wound round a lead wire 23 inserted under pressure into the groove 20 and fixed thereto, soldered and housed in the groove 21. In this constitution, the projection 18 is a stopper preventing the starting end 22 of the secondary coil from being positioned near to the primary coil, while the projection 19 prevents the occurrence of exfoliation of an epoxy resin mixture from the outer-peripheral surface of the projection 18.