A coil device includes two core members, one of which is E-shaped. The E-shaped core member has left and right side faces, and a center leg that extends in a vertical direction. A conducting wire is wound around a core, the core being composed of the two core members arranged to face each other in the vertical direction with a gap between the two core members. The conducting wire is wound around the center leg. First and second heat-sinking plates made of metal are bent so as to be in contact with upper and side faces of the core. The first and second plates are arranged so that first edges of the plates are placed left-right symmetrically with respect to the core with a gap between the edges. Second edges of the plates are in contact with a metal heat-sinking board where the core is placed.
1. A coil device comprising:
two core members,
at least either one of the two core members being an E-shaped core member,
the E-shaped core member having left and right side faces,
the E-shaped core member having a center leg that extends in a vertical direction;
a conducting wire that is wound around a core,
the core being composed of the two core members that are arranged to face each other in the vertical direction with a gap between the two core members,
the conducting wire being wound around the center leg; and
first and second heat-sinking plates that are composed of metal plates,
the first and second heat-sinking plates being bent so as to be in contact with upper and side faces of the core,
the first and second heat-sinking plates being arranged so that one edges of the first and second heat-sinking plates are placed left-right symmetrically with respect to the core with a space between the edges,
the first and second heat-sinking plates being formed so that another edges of the first and second heat-sinking plates are in contact with a metal heat-sinking board where the core is placed;
wherein a ratio ΔAw/W of a space Δw between the two heat-sinking plates to a width W of the core in a left-right direction is 0.3 or smaller.
2. The coil device according to claim 1 , wherein
the core is an El-shaped core including:
the E-shaped core member being the core member arranged in a lower side; and
an I-shaped core member being the core member arranged in an upper side.
3. The coil device according to claim 1 ,
the coil device further comprises means for maintaining constant the space between the first and second heat-sinking plates.