| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure for fastening a site of an upper side and a site of a lower side of a housing while suppressing the housing from being enlarged because there is a case of making the housing a structure capable of being separated into an upper and lower part for avoiding interference of the housing and a wing when assembling for increasing the diameter of the inner peripheral face of the housing from an air intake side to an outdoor air side.SOLUTION: A site of an upper side and a site of a lower side of a housing are fastened by a plurality of fastening element structures including a plurality of protruding parts arranged in one partial housing of an upper housing and a lower housing and extending to the other housing and a plurality of concave parts which are arranged in the other partial housing and into which the plurality of protruding parts fit in a border between the upper housing 131 and the lower housing 137 in which a diameter of an inner diameter 133 of a housing 13 increases downward from an air intake opening 231. |
