Abstract: A centrifugal fan 1 includes a main plate 10, a shroud 20, and a plurality of blades 30 provided between the main plate 10 and the shroud 20. The blade 30 includes abutting surfaces 34, 35a, and 35b that respectively abut on abutted surfaces 12a, 22a, and another abutted surface formed on at least one of the main plate 10 and the shroud 20. The abutting surfaces 34, 35a, and 35b includes projections 36, 37a, and 37b formed thereon, respectively, and extending in a straight or curved line. The abutting surfaces 34, 35a, and 35b and the abutted surfaces 12a, 22a, and the other abutted surface are respectively welded to each other by laser beams 40 and 41 respectively directed onto and moved along the projection 36 and the projections 37a and 37b.

Abstract: A centrifugal fan 1 includes a main plate 10, a shroud 20, and a plurality of blades 30 provided between the main plate 10 and the shroud 20. The blade 30 includes abutting surfaces 34, 35a, and 35b that respectively abut on abutted surfaces 12a, 22a, and another abutted surface formed on at least one of the main plate 10 and the shroud 20. The abutting surfaces 34, 35a, and 35b includes projections 36, 37a, and 37b formed thereon, respectively, and extending in a straight or curved line. The abutting surfaces 34, 35a, and 35b and the abutted surfaces 12a, 22a, and the other abutted surface are respectively welded to each other by laser beams 40 and 41 respectively directed onto and moved along the projection 36 and the projections 37a and 37b.

Abstract: A centrifugal fan includes a main plate fixed to a rotating shaft of a drive unit, a shroud having an air suction port, and a plurality of blades disposed between the main plate and the shroud. A rib for reinforcement is formed in each of the blades. Deformation due to an external pressure can be suppressed, the main plate, the shroud, and the blades are firmly fixed to each other, and a decrease in reliability, generation of noise, and the like due to deformation are suppressed.

Abstract: A resin composite hose of curved shape includes a resin layer having permeation resistance to a transported fluid and serving as a barrier layer, an inner rubber layer as an inner surface layer on an inner side of the resin layer and an outer rubber layer on an outer side of the resin layer. The resin composite hose has one axial end that is larger in diameter than the other axial end thereof. The resin composite hose has at least one curved portion. The curved portion is formed in a shape of progressively and continuously increasing diameter from a curve beginning end with a small diameter near the other axial end of the resin composite hose to a curve terminal end with a large diameter near the one axial end thereof.

Abstract: A package accommodates an LD device for emitting laser light with the center wavelength of which is in a range of 1300 to 1440 nm and airtight seals a light path extending from the LD device to an incident end of an optical fiber. The package is filled with a nitrogen gas at a standard atmospheric pressure with the amount of moisture limited to a value lower than 100000 ppm by volume or less. Therefore, the amount of moisture in the light path for laser light within the package is limited to 100000 ppm by volume or less.

Abstract: A package accommodates an LD device for emitting laser light with the center wavelength of which is in a range of 1300 to 1440 nm and airtight seals a light path extending from the LD device to an incident end of an optical fiber. The package is filled with a nitrogen gas at a standard atmospheric pressure with the amount of moisture limited to a value lower than 100000 ppm by volume or less. Therefore, the amount of moisture in the light path for laser light within the package is limited to 100000 ppm by volume or less.