Patent ID: 8779883

Claim:
A coil device comprising a bobbin having a bobbin plate provided with a first hollow cylinder, on which a primary coil is wound at an outer circumference, and a case provided with a second hollow cylinder readily mounted on an outer circumference of said primary coil and wound by a secondary coil at an outer circumference, and provided with a lower collar part which is formed at a lower end of said second hollow cylinder so as to be mounted on an upper surface of said bobbin plate, wherein on one end portion of said bobbin plate in a longitudinal direction, a plurality of primary terminals connecting to said primary coil are formed projecting out along the longitudinal direction of said bobbin plate, and on the other end portion of said bobbin plate in the longitudinal direction, a plurality of secondary terminals connecting to said secondary coil are formed projecting out along the longitudinal direction of said bobbin plate, and a tip end portion of the lower collar part of said case at a side of the secondary terminal is extended at least to the other end portion of said bobbin plate in a longitudinal direction to which said secondary terminal is formed, and plural first grooves for lead, which guide a lead wire of said secondary coil to a connection part with said secondary terminal, are formed on said tip end portion, a distance between the outer circumference of said primary coil and an inner circumference of said secondary coil changes along a circumferential direction and an intermediate region that passes a primary lead wire of said primary coil is provided between the outer circumference of said primary coil and the inner circumference of said secondary coil, at an inner circumference side of a winding bottom of said secondary coil, said outer circumference of said primary coil is positioned proximally to said inner circumference of said secondary coil sandwiching said second hollow cylinder, at the inner circumference side of the winding top of said secondary coil, the distance between the outer circumference of said primary coil and inner circumference of said secondary coil increases so that the intermediate region is made therebetween, and the primary lead wire of said primary coil passes through the intermediate region and is connected to the primary terminals.