Turbo fan and air conditioner

Patent metadata

Field	Value
Publication number	US-9829004-B2
Application number	US-201314428484-A
Country	US
Kind code	B2
Filing date	Oct 15, 2013
Priority date	Oct 16, 2012
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

Provided is a turbofan including a shroud, a main plate, and a plurality of blades. A main plate-side shoulder surface portion is curved so as to be distanced from the rotational center axis while approaching the blade trailing edge as the main plate-side shoulder surface portion is distanced from a main plate-side blade tip portion, and has a convexoconcave shape including a blade tip section and the main plate-side blade tip portion. An inner peripheral-side leading edge section includes the inner peripheral-side blade leading edge section main plate-side portion and an inner peripheral-side blade leading edge section tip-side portion including curves that protrude rearward in the rotational direction.

First claim

The invention claimed is:

1. A turbofan, comprising:
a shroud arranged on a suction side;
a main plate arranged to be opposed to the shroud; and
a plurality of blades arranged between the shroud and the main plate,
the shroud being formed so that a diameter is increased toward the main plate,
the main plate having a radially center part that is protruded toward the shroud,
the plurality of blades each being formed so that a blade leading edge is positioned closer to a rotational center axis than a blade trailing edge,
wherein the blade leading edge is inclined to be distanced from the rotational center axis RC as the blade leading edge is distanced from the main plate and has a zigzag shape including two convex portions that protrude forward in the rotational direction of the fan,
wherein the blade leading edge comprises:
an inner peripheral-side leading edge section;
a shroud-side leading edge section; and
a blade tip section positioned between the inner peripheral-side leading edge section and the shroud-side leading edge section,

wherein the inner peripheral-side leading edge section comprises:
an inner peripheral-side blade leading edge section main plate-side portion;
an inner peripheral-side blade leading edge section tip-side portion;
a main plate-side blade tip portion; and
a main plate-side shoulder surface portion,

wherein the inner peripheral-side blade leading edge section main plate-side portion, the main plate-side blade tip portion, the main plate-side shoulder surface portion, and the inner peripheral-side blade leading edge section tip-side portion are formed in the stated order from the main plate toward the shroud,
wherein the inner peripheral-side blade leading edge section main plate-side portion is distanced from the blade trailing edge and the rotational center axis as the inner peripheral-side blade leading edge section main plate-side portion is distanced from the main plate,
wherein the inner peripheral-side blade leading edge section main plate-side portion is bent in a direction to form a concavity that extends oppositely to the rotational direction,
wherein the main plate-side blade tip portion is a convex portion that protrudes forward in the rotational direction,
wherein the main plate-side shoulder surface portion is distanced from the rotational center axis while approaching the blade trailing edge as the main plate-side shoulder surface portion is distanced from the main plate-side blade tip portion, and
wherein the inner peripheral-side blade leading edge section tip-side portion is distanced from the blade trailing edge and the rotational center axis as the inner peripheral-side blade leading edge section tip-side portion is distanced from the main plate.

2. A turbofan according to claim 1 , wherein, when viewed in a plane orthogonal to the rotational center axis, the blade tip section is positioned forward in the rotational direction with respect to the main plate-side blade tip portion.

3. A turbofan according to claim 1 ,
wherein, when the inner peripheral-side blade leading edge section main plate-side portion and the inner peripheral-side blade leading edge section tip-side portion are viewed from a forward side toward a rearward side in the rotational direction, a first angle is formed between a straight line parallel to the rotational center axis and a thickness centerline of the inner peripheral-side blade leading edge section main plate-side portion, and a second angle is formed between the straight line parallel to the rotational center axis and the inner peripheral-side blade leading edge section tip-side portion, and
wherein the following relationship is satisfied: the first angle is greater than or equal to the second angle.

4. A turbofan according to claim 3 , wherein each of the thickness center lines is bent forward in the rotational direction so that each of the angle relating to the inner peripheral-side blade leading edge section main plate-side portion and the angle relating to the inner peripheral-side blade leading edge section tip-side portion is gradually increased from a position separated from the main plate.

5. A turbofan according to claim 1 ,
wherein the blade trailing edge is positioned on a virtual cylindrical surface formed by a main plate outer periphery and a shroud outer periphery, and comprises a main plate-side blade trailing edge, a shroud-side blade trailing edge, and a point of curvature,
wherein the point of curvature is positioned at a boundary between the main plate-side blade trailing edge and the shroud-side blade trailing edge,
wherein the main plate-side blade trailing edge is positioned on the main plate side with respect to the point of curvature, and the shroud-side blade trailing edge is positioned on the shroud side with respect to the point of curvature,
wherein a blade outer surface of the main plate-side blade trailing edge until the point of curvature is inclined rearward in the rotational direction as the blade outer surface is distanced from the main plate, and a blade inner surface of the main plate-side blade trailing edge until the point of curvature is inclined forward in the rotational direction as the blade inner surface is distanced from the main plate, so that a thickness of the main plate-side blade trailing edge is gradually reduced from a main plate-side trailing edge end point to the point of curvature,
wherein the shroud-side blade trailing edge is inclined rearward in the rotational direction both in the blade outer surface and the blade inner surface, and is connected to the shroud at a shroud-side trailing edge end point, and
wherein the blade outer surface of the shroud-side blade trailing edge is inclined rearward in the rotational direction more on the shroud side as compared to the main plate side, and is inclined rearward in the rotational direction from the main plate to the shroud to be gradually distanced from the blade leading edge as the blade outer surface is distanced from the main plate.

6. An air conditioner, comprising:
a main body having an air inlet and an air outlet formed through one surface thereof;
the turbofan according to claim 1 , which is arranged inside the main body to be communicated with the air inlet; and
an air conditioning unit arranged between the turbofan and the air outlet.

7. A turbofan according to claim 1 ,
wherein the main plate-side blade tip portion is a convex portion that protrudes forward in the rotational direction,
wherein the main plate-side shoulder surface portion is distanced from the rotational center axis while approaching the blade trailing edge as the main plate-side shoulder surface portion is distanced from the main plate-side blade tip portion, and
wherein the inner peripheral-side blade leading edge section tip-side portion is distanced from the blade trailing edge and the rotational center axis as the inner peripheral-side blade leading edge section tip-side portion is distanced from the main plate.

Assignees

• Mitsubishi Electric Corp

Inventors

• Ikeda Takashi
• Takagi Masahiko
• Kurihara Makoto

Classifications

• F04D29/281 Primary

  for fans or blowers · CPC title

• F04D29/388

  characterised by construction · CPC title

• F04D19/002

  Axial flow fans · CPC title

• F04D29/384

  characterised by form · CPC title

• F04D25/088 Primary

  Ceiling fans · CPC title