bobbin

Abstract

The present article is a bobbin used in transformers, reactors, choke coils, etc., on which a winding is wound. The bobbin has a first cylindrical portion around which the primary winding is wound, a second cylindrical portion around which the secondary winding is wound, a primary-side flange through which the primary winding is inserted, and a secondary-side flange through which the secondary winding is inserted. The first and second cylindrical portions are separated by a separator. The wall surface of the separator, the circumferential surface of the second cylindrical portion, is provided with an annular step that protrudes outward from the separator, and the secondary winding is wound so that it rides on the protruding step. The step is provided with a circumferential groove, and lateral grooves are provided on the circumferential surfaces of the first and second cylindrical portions. The circumferential groove and lateral groove are permeable to heat-dissipating resin when the primary winding and secondary winding are wound therein. Furthermore, a core hole is drilled in the axial direction of the bobbin, and a core is inserted into the core hole. The bobbin has a plurality of protrusions on the inner peripheral surface thereof, and a gap is formed between the core and the inner peripheral surface of the core hole via the protrusions. The protrusions on the bottom side of the bobbin are located at positions corresponding to the lateral grooves. The bobbin has legs on the bottom.

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