TRANSFORMER

PROBLEM TO BE SOLVED: To prevent the temperature of a transformer core from rising in order to prevent voltage transformation efficiency of a transformer from being reduced.SOLUTION: A transformer 1 includes a transformer core 2. Each of a pair of E-shaped cores 3 and 4 includes a central magnetic leg 20, a pair of side magnetic legs 21 disposed to hold the central magnetic leg 20 therebetween, and a yoke part 22 connecting one end of the central magnetic leg 20 and one-side ends of the pair of side magnetic legs 21. The transformer core 2 is formed by abutting another end of the central magnetic leg 20 and other-side ends of the side magnetic legs 21 in the pair of E-shaped cores 3 and 4. The transformer 1 is disposed on a circuit board 9 that is cooled by cooling means 10. The transformer core 2 of the transformer 1 is disposed in such a manner that one E-shaped core 4 is positioned closer to the circuit board and the other E-shaped core 3 is positioned oppositely to the circuit board 9 with respect to the one E-shaped core 4. In at least a pair of central magnetic legs 20, a heat conduction member 8, of which the heat conductivity is higher than that of the E-shaped cores 3 and 4, is disposed in contact with both the pair of central magnetic legs 20. 【課題】トランスの電圧変換効率の低下を抑制するため、トランスコアの温度上昇を抑制する。【解決手段】トランス１は、中央磁脚２０と、中央磁脚２０を挟むように配置された一対の側磁脚２１と、中央磁脚２０の一端及び一対の側磁脚２１の一端を連結するヨーク部２２と、を有する一対のＥ型コア３、４を、中央磁脚２０及び側磁脚２１の各他端同士を突き合わせて形成されたトランスコア２を備え、冷却手段１０により冷却される回路基板９上に配置される。トランス１のトランスコア２は、一方のＥ型コア４が回路基板側に位置し、他方のＥ型コア３が一方のＥ型コア４に対して回路基板９と反対側に位置するよう配置され、少なくとも一対の中央磁脚２０には、Ｅ型コア３、４よりも熱伝導率の高い伝熱部材８が一対の中央磁極２０の両方と接するように配置されている。【選択図】図２