Bobbin, coil-wound bobbin, and method of producing coil-wound bobbin

A bobbin comprising:

• two spool portions having a hollow circular cylinder shape, axially aligned to each other with an end-to-end basis, and each adapted to have a wire wound thereon in multilayer alignment;
• two flanges each integrally disposed at a proximal end of each of the two spool portions;
• and
• a terminal pin block integrally disposed on the two flanges so as to bridge between the two flanges and adapted to terminate the wire,
• wherein two inner yokes each having a plurality of pole teeth at its inner circumference are insert-molded with the bobbin.

A coil-wound bobbin comprising:

• a bobbin comprising a spool portion having a hollow circular cylinder shape, a flange integrally disposed at one end of the spool portion, and a terminal block integrally disposed on the flange and adapted to terminate a wire;
• and
• a coil disposed on the bobbin such that a self-fusing wire is wound on the spool portion of the bobbin in multilayer alignment, wherein a formula:
• D×N−D/2<L<D×N+D/2 is established, where L is an effective length of the spool portion, D is a diameter of the wire, and N is a number of turns of the wire for a first layer of the multilayer alignment.

A method of producing a coil-wound bobbin in which a bobbin comprises:

• a spool portion having a hollow circular cylinder shape;
• a flange integrally disposed at one end of the spool portion;
• and
• a terminal block disposed on the flange, having a plurality of terminal pins implanted therein, and adapted to terminate a wire, the method comprising steps of:
• (a) placing the bobbin on a spindle of a wire winding machine;
• (b) setting a wire holder of the wire winding machine so as to provide a distance equal to an integral multiple of a diameter of the wire from the flange of the bobbin;
• (c) wrapping a starting lead-out line of the wire around one terminal pin of the plurality of terminal pins, guiding the starting lead-out line in contact with the flange to the spool portion of the bobbin, forming a first turn for a first layer of the coil around the spool portion, forming a second turn for the first layer in tight contact with the first turn until filling up the distance provided thereby completing a predetermined number of turns for the first layer, forming a second layer of the coil by making a necessary number of turns in an opposite direction until completing a predetermined number of layers, and wrapping a finishing lead-out line of the wire around another terminal pin of the plurality of terminal pins;
• and
• (d) detaching the wire holder of the wire winding machine from the coil, and releasing the bobbin having the wire wound therearound thus finishing a coil-wound bobbin.