US Patent 7117580 Method of manufacturing a watertight brushless fan motor

A method of manufacturing a watertight brushless fan motor includes first, combining a stator assembly with a stator and a circuit substrate, a case, a die, and an annular member. The stator assembly is mounted on the bearing supporting cylindrical section of the case. The bearing supporting cylindrical section is engaged and the die and annular member are fixed to the case. An insulating resin is poured into the die to mold spaces between the plate-like section and the bearing supporting cylindrical section so that the stator and the circuit substrate are included inside. The resin may be poured under low vacuum. With this arrangement, the watertight brushless fan motor is provided that can prevent occurrence of a crack in the outer surface of the molded part due to molding shrinkage of the insulating resin or expansion and shrinkage of the insulating resin caused by a change in ambient temperature.