FITTING STRUCTURE OF BOARD

摘要

PROBLEM TO BE SOLVED: To provide a fitting structure of a board wherein a stress on the board which is caused by dimensional difference between a case side and a board is reduced while a fitting work of the board to the case is more efficient. SOLUTION: A board 15 comprising a power transistor 20 is housed in a case 11. The board 15 is fixed to a protrusion 14 provided on a side wall 13 of the case 11 through a plurality of heat sinks 16. The power transistor 20 is fitted to an element fitting part 19 of the heat sink 16. The direction of screwing for fitting a case side fitting part 18 of the heat sink 16 to the protrusion 14 is set to be vertical to the board 15 from a board 15 side. Thus, the stress on the board 15 caused by a dimensional difference between the board side and the case side for a plane direction of the board 15 is reduced.