Ignition coil for an internal combustion engine

Abstract

The invention is directed to an ignition coil for an internal combustion engine which includes a columnar member having a plurality of magnetic plates, e.g., silicon steel plates stacked one on the other, each of which is a flat plate with its opposite ends having a width greater than that of its middle portion. Each silicon steel plate has a middle portion whose width is gradually increased from the plates placed at the opposite sides of the columnar member to the plate placed in the center of the columnar member, to form a circular cross section. Whereas, the opposite end portions of the columnar member have a rectangular cross section which is greater in area than the circular cross section of the middle portion, respectively. A plurality of recesses are formed on one side of each steel plate, and a plurality of protrusions are formed on the other side of each steel plate. The silicon steel plates stacked one on the other under pressure, so that the recesses and the protrusions are connected to form a plurality of stacked portions on the columnar member. The ignition coil further includes a primary winding and a secondary winding which are wound around the columnar member, a magnetic cylindrical member in which the columnar member is received, and a magnetic cylindrical case in which the cylindrical member and the columnar member are received.

Dependencies are inferred from the claim text.