| CPC F04D 29/281 (2013.01) [F04D 29/388 (2013.01); F04D 29/66 (2013.01)] | 10 Claims |
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1. A centrifugal blower comprising:
a plurality of blades that are arranged in a circumferential direction about a central axis;
a shroud that is shaped in a ring form centered on the central axis and covers the plurality of blades from one axial side in an axial direction of the central axis, wherein the shroud forms a suction port that is located on an inner side of the shroud in a radial direction of the central axis and opens in the axial direction;
a main plate that is shaped in a ring form centered on the central axis and covers the plurality of blades from another axial side which is opposite to the one axial side in the axial direction, wherein the main plate forms an opening that opens in the axial direction and is located on an inner side of the main plate in the radial direction; and
a tubular portion that is placed in the opening and is shaped in a cylindrical tubular form centered on the central axis, wherein the tubular portion is configured to be rotated about the central axis by a rotational force of an electric motor, wherein:
the plurality of blades, the shroud and the tubular portion are integrally formed in one-piece as an integrated component;
an air flow passage is formed between each adjacent two of the plurality of blades at an axial location that is between:
the tubular portion and the main plate; and
the shroud;
the tubular portion is coupled to the main plate in a manner that limits relative movement of the tubular portion relative to the main plate;
when the plurality of blades, the shroud, the tubular portion and the main plate are rotated toward one circumferential side in the circumferential direction by the rotational force of the electric motor, air, which is suctioned from the one axial side into the suction port in the axial direction, is conducted through the air flow passage formed between each adjacent two of the plurality of blades and is discharged toward a radially outer side in the radial direction;
the shroud has a cover region, which faces the another axial side in the axial direction and is configured to cover a side of the tubular portion which faces the one axial side in the axial direction, wherein in a cross-section of the shroud which is taken along a plane that includes the central axis, the cover region is shaped in a convex arcuate form that is convex toward the another axial side in the axial direction;
the cover region of the shroud is sloped to progressively approach the one axial side in the axial direction from a radially outer end of the cover region toward a radially inner end of the shroud in the radial direction;
an axial end part of the tubular portion, which faces the one axial side in the axial direction, has an end surface; and
a line, which is perpendicular to the axial direction and is also perpendicular to the radial direction, is defined as a first virtual line, and a tangent line, which is perpendicular to the first virtual line and is tangent to the cover region, is defined as a second virtual line, and the cover region and the end surface are formed to implement that the end surface of the tubular portion and the second virtual line are parallel to each other, or a distance, which is measured between the end surface and the second virtual line in the axial direction, is progressively increased from a radially inner part of the end surface to a radially outer part of the end surface.
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