Abstract: A support frame portion is divided into a first support-frame half-portion and a second support-frame half-portion along a virtual reference dividing plane. A raised portion is integrally formed with each of side walls in a pair of the first web half-portion, projecting toward the second web half-portion beyond the virtual reference dividing plane. A raised portion is integrally formed with each of side walls in a pair of the second web half-portion, projecting toward the first web half-portion beyond the virtual reference dividing plane. A recessed portion is formed in each of the side walls in the pair of the first web half-portion, and is fitted with the raised portion corresponding thereto of the second web half-portion. A recessed portion is formed in each of the side walls in the pair of the second web half-portion, and is fitted with the raised portion corresponding thereto of the first web half-portion.

Abstract: A support frame portion is divided into a first support-frame half-portion and a second support-frame half-portion along a virtual reference dividing plane. A raised portion is integrally formed with each of side walls in a pair of the first web half-portion, projecting toward the second web half-portion beyond the virtual reference dividing plane. A raised portion is integrally formed with each of side walls in a pair of the second web half-portion, projecting toward the first web half-portion beyond the virtual reference dividing plane. A recessed portion is formed in each of the side walls in the pair of the first web half-portion, and is fitted with the raised portion corresponding thereto of the second web half-portion. A recessed portion is formed in each of the side walls in the pair of the second web half-portion, and is fitted with the raised portion corresponding thereto of the first web half-portion.

Abstract: A counter-rotating axial-flow fan includes a housing that is constituted from a first divided housing unit and a second divided housing unit. Engaging members and first stopper portions are integrally formed with a first flange portion of the first divided housing unit. The first stopper portions are arranged adjacent to the engaging members. Engaged members and second stopper portions are integrally formed with a second flange portion of the second divided housing unit. The second stopper portions are arranged adjacent to the engaged members. The second stopper portions have leading ends that are abutted onto leading ends of the first stopper portions when the engaging members are completely engaged with the engaged members. Thus, damage of the first and second divided housing units is prevented when the first and second divided housing units are coupled.