JP2008138660A5 - - Google Patents

Claims (15)

An electric motor in which an impeller is connected to be rotatable about a rotation axis, a casing having a suction port surrounding the impeller, and an opening communicating with the opening of the outer shell. A centrifugal mouth blower that resonates and muffles noise emitted from the suction port by a resonance space formed by the orifice, from an inlet portion between the end of the orifice and the casing. A part of the path until the sound wave of the noise incident on the resonance space is reflected is lengthened,
A cylindrical body in which a wall is provided in the resonance space, a part of the path until the sound wave of noise incident on the resonance space is reflected is lengthened, and the wall provided in the resonance space is concentric with the suction port and has one end in contact with the casing Is a centrifugal blower. 2. The centrifuge according to claim 1, wherein an inner diameter D of a cylindrical tubular wall concentric with the suction port provided in the resonance space has a relationship of D> Di + 2i between the inner diameter Di of the suction port and a gap dimension i of the inlet portion. Blower. 2. The centrifuge according to claim 1, wherein an inner diameter D of a cylindrical tubular wall concentric with the suction port provided in the resonance space has a relationship of D <Di + 2i between the inner diameter Di of the suction port and a gap dimension i of the inlet portion. Blower. The centrifugal blower according to any one of claims 1 to 3, wherein an inner diameter D of a cylindrical wall body concentric with a suction port provided in the resonance space is not uniform in a circumferential direction. The centrifugal blower according to any one of claims 1 to 4, wherein the height of the cylindrical wall body concentric with the suction port provided in the resonance space is not uniform in the circumferential direction. The centrifugal blower according to any one of claims 1 to 5, wherein the gap dimension i at the entrance to the resonance space is not uniform in the circumferential direction. The centrifugal blower according to any one of claims 1 to 6, wherein an inner diameter D of a cylindrical tubular wall body concentric with a suction port provided in the resonance space is adjustable. The centrifugal blower according to any one of claims 1 to 7, wherein a height of a cylindrical tubular wall concentric with a suction port provided in the resonance space is adjustable. At least one cylindrical tubular wall that is concentric with the suction port of the casing and has one end in contact with the casing, and at least one cylindrical tubular wall that is concentric with the suction port of the casing and has one end in contact with the orifice is provided in the radial direction. The centrifugal blower according to any one of claims 1 to 8, which is arranged alternately. The centrifugal blower according to any one of claims 1 to 9, wherein a cylindrical tubular wall body concentric with a suction port provided in the resonance space is formed integrally with the casing. The centrifugal blower according to claim 1, further comprising a partition wall that divides the resonance space into a plurality of parts. The centrifugal blower according to claim 11, wherein walls having different shapes are provided in each of the plurality of resonance spaces, and a part of a path until a sound wave of noise is reflected in each resonance space is lengthened. The centrifugal blower according to claim 11 or 12, wherein a gap dimension i at an inlet portion of each of the plurality of resonance spaces is different. The centrifugal blower according to any one of claims 1 to 13, wherein an outer peripheral space surrounded by a side wall and an outer shell of the casing is used as a resonance space. The centrifugal blower according to claim 14, wherein a rear space between the outer wall of the casing on the motor side and the outer shell is used as a resonance space.