| 摘要 |
PURPOSE:To prevent the thermal breakdown of a solder part between an insulating plate and a metal case, by fixing a magnet in a part of a metal case, which faces a heat sink comprising a ferromagnetic material with the insulating plate in-between. CONSTITUTION:Owing to the heating of a power element 1, strain due to the difference in thermal expansion coefficients of an insulating plate 3 and a metal case is yielded in solder 5 between the plate 3 and the case 4. Separated parts 51 are yielded by the cracks in the parts of the solder 5, where the strain is yielded. The irregularities at the parts 51 have matching shapes. A heat sink 2 comprising a ferromagnetic material faces a magnet 7, which is provided in the metal case 4 with the insulating plate 3 in-between. The heat sink 2 and the magnet 7 are attracted. Therefore, the irreguralities in the separated solder parts are coupled together. |
