| 摘要 |
PROBLEM TO BE SOLVED: To provide an air fan used in a combustion device for burning fuel gas, without increasing noise even by long-term use.SOLUTION: A rotary shaft of a motor is inserted into an installation hole of a substrate in a state of sandwiching the substrate of a rotary blade part by rubber members from both surface sides, and the substrate is fastened by a screw to the rotary shaft by including the rubber members by using a nut. At this point, a metallic spring is inserted between the nut and the rubber member. Thus, even if a permanent set is caused in the rubber member, the permanent set can be absorbed by restoration of the metallic spring. Therefore, the substrate can be pressed by proper force by the rubber members, and looseness of the rotary blade part can be restrained. As a result of it, an increase in the noise of the air fan by the long-term use can be avoided. |
