| 摘要 |
PURPOSE:To improve the durability of bearing section by a method wherein the device is constituted so that the fan is positioned at a position whereat the rotating number of the fan becomes minimum when the position of the fan is displaced into the axial direction thereof under a condition that the temperature in the housing and the voltage of a motor are constant, in the hot-air type heating cooker. CONSTITUTION:In a relation between the position of the fan 9 in a heating box 7 and the rotating number of the fan 9, the rotating number of the fan becomes minimum at a constant distance (l) from the rear wall 6 of the heating chamber under a condition that the temperature in the box is kept in a given value while a difference between the temperature of the hot-air near the blow-off port 11 at the rear wall 6 of the heating chamber and the temperature at the center of the box becomes also minimum. Accordingly, the position of the tip end of a rotating shaft 17 for a motor 16, for example, is fixed at a position apart from the rear wall 6 of the heating chamber by the distance (l) whereat the rotating number of the fan becomes minimum. According to this method, the working efficiency of the fan 9 may be maximized, the durabilities and qualities of bearings, rotating shaft and the like as well as the safety of the device may be improved. |
