Centrifugal multiblade fan

Abstract

A centrifugal multiblade fan according to the present invention sucks air from one end side of an axial direction of a rotation axis to a radial inside, and blows the air to a radial outside. The centrifugal multiblade fan includes a plurality of blades located around the rotation axis. Each blade has a leading edge positioned at the radial inside, and a trailing edge positioned at a radial outside. The leading edge of each blade has an edge shape with a radius of curvature of 0.2 mm or less, for example.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments when taken together with the accompanying drawings. In the drawings:

FIG. 1 is a partial cross-sectional view of a blower including a centrifugal multiblade fan according to a first embodiment of the invention;

FIG. 2 is a front view of the blower in FIG. 1;

FIG. 3 is an enlarged cross-sectional view showing a part of the centrifugal multiblade fan according to the first embodiment;

FIG. 4 is a pattern diagram showing airflow between blades of the centrifugal multiblade fan according to the first embodiment;

FIG. 5A is a graph showing a relationship between a maximum thickness position of the blades of the centrifugal multiblade fan and a specific noise level, and FIG. 5B is a graph showing a relationship between the maximum thickness position of the blades and a fan efficiency according to the first embodiment;

FIG. 6 is an enlarged cross-sectional view showing a part of a centrifugal multiblade fan according to a comparative example 2;

FIG. 7A-FIG. 7D are graphs showing effects due to the invention;

FIG. 8 is a view showing a specification of blades in the first embodiment and the comparative example 2, used for measuring in FIGS. 7A-7D;

FIG. 9 is an enlarged cross-sectional view showing a part of a centrifugal multiblade fan according to the second embodiment; and

FIG. 10 is an enlarged cross-sectional view showing a part of a centrifugal multiblade fan according to the third embodiment.

Claims

1. A centrifugal multiblade fan that sucks air from one end side of an axial direction of a rotation axis to a radial inside, and blows the air to a radial outside, wherein the centrifugal multiblade fan comprising a plurality of blades located around the rotation axis,wherein each blade has a leading edge positioned at the radial inside, and a trailing edge positioned at a radial outside, andwherein the leading edge of each blade has an edge shape with a radius of curvature of 0.2 mm or less.

2. The centrifugal multiblade fan according to claim 1, wherein each blade has a ventral surface on a forward side in a rotation direction, and a back surface opposite to the ventral surface,wherein the leading edge has a first angle part on a side of the ventral surface, and a second angle part on a side of the back surface, andwherein at least the second angle part has the edge shape with a radius of curvature of 0.2 mm or less.

3. The centrifugal multiblade fan according to claim 1, wherein the edge shape of the leading edge is a sharply peaked shape.

4. The centrifugal multiblade fan according to claim 1, wherein a blade thickness of each blade increases gradually from both the leading edge and the trailing edge to a thickness portion in a chordwise direction.

5. The centrifugal multiblade fan according to claim 4, wherein a ratio (Lm/Lc) of a chordwise distance (Lm) from the leading edge to the thickness portion and a chord length (Lc) from the leading edge to the trailing edge of each blade is set in a range from 0.4 to 0.6.

6. The centrifugal multiblade fan according to claim 5, wherein the ratio (Lm/Lc) is set in a range from 0.45 to 0.55.

7. A centrifugal multiblade fan that sucks air from one end side of an axial direction of a rotation axis to a radial inside, and blows the air to a radial outside, wherein the centrifugal multiblade fan comprising a plurality of blades located around the rotation axis,wherein each blade has a leading edge positioned at the radial inside, and a trailing edge positioned at a radial outside,wherein each blade has a ventral surface on a forward side in a rotation direction, and a back surface opposite to the ventral surface,wherein the leading edge has a first angle part on a side of the ventral surface, and a second angle part on a side of the back surface, andwherein at least the second angle part has an edge shape.

8. The centrifugal multiblade fan according to claim 7, wherein the leading edge has a substantially flat surface on the radial inside.

9. A centrifugal multiblade fan that sucks air from one end side of an axial direction of a rotation axis to a radial inside, and blows the air to a radial outside, wherein the centrifugal multiblade fan comprising a plurality of blades located around the rotation axis,wherein each blade has a leading edge positioned at the radial inside, and a trailing edge positioned at a radial outside,wherein the leading edge has an edge-shaped part such that air from the one end side of the axial direction of the rotation axis is always separated at the edge shaped part.