Coil component, transformer and switching power supply unit

A transformer comprising a coil component, the coil component comprising:

• a first coil winding formed by joining a plurality of plate-like coil members in a ring shape having ends wound around a first axis and having a portion defining an opening in center thereof;
• a second coil winding formed of members of a same form as the first coil winding wound around a second axis running along the first axis, juxtaposed to the first coil winding, and having a portion defining an opening in center thereof;
• a connecting member configured to electrically connect together an end of the first coil winding to an end of the second coil winding, the connected ends of the first and second coil windings being disposed in a same direction along an extending axis of the first axis and the second axis with respect to the first coil winding and the second coil winding;
• and
• a heat conductive member having electrical insulation properties and provided to contact the connecting member, wherein
• the first coil winding and the second coil winding are each wound such that magnetic flux is generated by a current flowing through the first coil winding and the second coil winding to pass through the opening of the first coil winding in one direction and through the opening of the second coil winding in an opposite direction to the direction passing through the opening of the first coil winding,
• on an inner perimeter edge of the coil members, a cutout portion where a portion of the coil members is outwardly cut is formed, and
• in an area of an outer perimeter edge of the coil members that are an extension of a line connecting a center axis of the opening and the cutout portion, a protrusion where a portion of the coil members are outwardly bulged is provided such that the outer perimeter edge of the coil members becomes larger in a radial direction.

A switching power supply unit comprising a coil component, the coil component comprising:

• a first coil winding formed by joining a plurality of plate-like coil members in a ring shape having ends wound around a first axis and having a portion defining an opening in center thereof;
• a second coil winding formed of members of a same form as the first coil winding wound around a second axis running along the first axis, juxtaposed to the first coil winding, and having a portion defining an opening in center thereof;
• a connecting member configured to electrically connect together an end of the first coil winding to an end of the second coil winding, the connected ends of the first and second coil windings being disposed in a same direction along an extending axis of the first axis and the second axis with respect to the first coil winding and the second coil winding;
• and
• a heat conductive member having electrical insulation properties and provided to contact the connecting member, wherein
• the first coil winding and the second coil winding are each wound such that magnetic flux is generated by a current flowing through the first coil winding and the second coil winding to pass through the opening of the first coil winding in one direction and through the opening of the second coil winding in an opposite direction to the direction passing through the opening of the first coil winding,
• on an inner perimeter edge of the coil members, a cutout portion where a portion of the coil members is outwardly cut is formed, and
• in an area of a outer perimeter edge of the coil members that are an extension of a line connecting a center axis of the opening and the cutout portion, a protrusion where a portion of the coil members are outwardly bulged is provided such that the outer perimeter edge of the coil members becomes larger in a radial direction.