A device for forming the casing of centrifugal fan

摘要

Even if the casing of the centrifugal type blower is enlarged, it is possible to form the side plate and the back plate without causing partial thermal deformation in the manufacturing process, and the process of forming the engaging groove in the back plate and the process of joining the side plates, And to provide a device that can be molded. A forming roll 7 for forming an engaging groove 6 having both U-shaped cross sections and required for the back plate 3 on both side edges of the band-shaped blade 20 and for delivering the working material; And an engaging roller 8 for deforming the engaging groove 6 to which the edge portion is engaged by a pressing force from the side and fixing the side edge of the back plate 3 to the periphery of the side plate 2. [ A centrifugal blower (not shown) in which the spiral wound portion 2A and the straight edge portion 2B are connected to each other and which surrounds the circumferential edge of the opposite side plate, (See Figs. 5 and 20).