JPH10141284A - Impeller of blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve static pressure efficiency of a blower of thick wall and vane-shaped form. SOLUTION: On the rotational locus of a plurality of vanes for constituting an impeller 1, of thick wall and vane-shaped, only the front edge 4 of each vane 2 is curved into a recessed shape in relation to the upstream side so as to have the maximum curvature at a part near the radius-root-means square position, and the front edge on the plane view of each vane 2 is constituted of a straight line provided with an approximately triangular protrusion of the front edge, and the section in the radial direction of each vane 2 is formed into a curved line recessed toward a tip part 6 on the outer periphery of the vane 2 in relation to the upstream side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impeller of a blower for performing a blowing action, and more particularly to a geometric shape of a blade having a thick airfoil shape.

[0002]

2. Description of the Related Art A conventional thick airfoil blower has a structure as shown in FIGS. That is, a plurality of thick and airfoil-shaped blades 10 are provided around a substantially cylindrical hub 14.

[0003] A leading edge 11 and a trailing edge 1 are shown on a rotation locus diagram of a plurality of thick and airfoil-shaped blades 10 constituting the impeller.
2 both consisted of straight lines.

[0004] Even when the radial cross section of the blade 10 approaches the tip portion 13 on the outer periphery of the blade 10, the suction surface 15 is substantially straight, and the pressure surface 16 is also substantially straight except for the vicinity of the tip portion 13. Met.

[0005] As a blower, the impeller is housed in an appropriate casing and rotated to produce a blowing action. The impeller rotates by fixing a motor shaft to a hub 14.

[0006]

However, in the above-described conventional configuration, the rotation locus diagram of the blade is also composed of straight lines,
The cross section in the radial direction of the blade is also linear except for a part,
There is a limit in controlling the tip vortex generated near the tip of the blade, and there has been a demand for further improvement of the static pressure efficiency of the blower.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide an improved static pressure efficiency of a blower having a thick airfoil shape.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a rotational locus diagram of a plurality of thick and airfoil-shaped blades constituting an impeller. Has a concave curve with respect to the upstream side so as to have the maximum curvature near the root mean square position, and the leading edge on the plan view of the blade is also a straight line having a substantially triangular projection. The radial cross section of the blade has a concave curved shape toward the upstream side as it approaches the tip portion on the outer periphery of the blade.

According to the above configuration, the tip vortex generated on the suction surface near the tip of the blade due to the leakage flow from the pressure surface to the suction surface can be stably held by the concave curved portion. By promoting the generation, the effect of improving the static pressure efficiency of the blower can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is characterized in that only the leading edge of the blade has a root-mean-square radius on a rotation locus diagram of a plurality of thick, airfoil-shaped blades constituting an impeller. The blade has a concave curve with respect to the upstream side so as to have a maximum curvature near the position, and the front edge of the blade in a plan view is formed of a straight line having a substantially triangular projection, The cross section in the radial direction of the blade has a curved shape concave toward the upstream side as it approaches the tip portion on the outer periphery of the blade.

According to this configuration, the tip vortex generated on the suction surface near the tip portion of the blade due to the leakage flow from the pressure surface to the suction surface can be stably held by the concave curved portion. By promoting the generation of the end vortex, the static pressure efficiency of the blower can be improved.

According to a second aspect of the present invention, the ratio t / c of the maximum thickness t to the chord length c at the root mean square position of the blade having a thick airfoil shape is 5 to 12%. In this case, the low-noise effect and the high static pressure efficiency can both be obtained with the thick-walled blade in comparison with the thin-wall blade having a constant thickness.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a first embodiment of the present invention.
-It will be described with reference to FIGS. 2, 3, and 6.

FIG. 1 is a plan view of an axial blower impeller of the present invention. FIG. 2 is a rotation locus diagram of the axial blower impeller of the present invention.

FIG. 3 is a radial sectional view of the blade of the axial blower impeller of the present invention. FIG. 6 is a schematic diagram showing an operation state of the axial blower impeller of the present invention.

The axial blower impeller 1 is provided with a blade 2 on a hub 3 on a substantially cylindrical shape. As shown in FIG. 6, the shaft of the motor 9 is fixed to the hub 3 of the axial blower impeller 1,
It is housed in a suitable casing 10 and is rotated in the direction of the arrow by a motor to produce a blowing action. At this time, FIG.
Thus, the air enters from the leading edge 4 of the blade 2 and flows out from the trailing edge 5 to perform aerodynamic work.

Here, as shown in FIG. 2, on the rotational locus diagram of a plurality of thick and airfoil-shaped blades 2 constituting the axial-flow blower impeller 1, only the leading edge 4 is the root mean square position. The curve is concave toward the upstream side so as to have the maximum curvature in the vicinity. Further, the front edge of the blade 2 on the plan view is formed of a straight line having a substantially triangular projection.

As shown in FIG. 3, as the radial cross section of the blade 2 approaches the tip portion 6 on the outer periphery of the blade 2, both the pressure surface 8 and the suction surface 7 have concave curved shapes toward the upstream side. Is what you do.

With the above configuration, the pressure surface 8 to the suction surface 7
Wing vortex generated on the negative pressure surface near the tip 6 of the blade due to the leakage flow toward the blade can be stably held in the concave curved portion, and by promoting the generation of the wing vortex, the static pressure of the blower can be increased. The effect of improving the efficiency is obtained.

(Embodiment 2) FIG. 4 shows a second embodiment of the present invention.
-It will be described with reference to FIG. FIG. 4 is a correlation diagram between the maximum thickness / chord length ratio and noise (A). FIG. 5 is a characteristic curve of the axial blower impeller of the present invention.

According to this embodiment, the ratio t / c of the maximum thickness t to the chord length c at the root mean square position of the blade 2 having a thick airfoil shape is set to 5 to 12% from FIG. Things.

As a result, the low-noise effect of the thick blade-shaped blade 2 is exhibited for the first time as compared with a thin-wall blade having a constant thickness, and both low noise effect and high static pressure efficiency can be obtained.

FIG. 5 shows the effect. It shows the static pressure characteristics and the static pressure efficiency characteristics of the present invention and the conventional axial flow fan, and is data of an outer diameter φ350. The axial blower of the present invention is about 10% better in static pressure efficiency.

Note that these techniques are not limited to the axial blower, and the same effects can be obtained with a mixed flow blower.

[0026]

As is apparent from the above embodiment, the invention according to the first aspect is characterized in that a plurality of thick and airfoil-shaped blades constituting an impeller are arranged in front of the blades on the rotation locus diagram. A straight line having a concave curve toward the upstream side so that only the edge has the maximum curvature near the root mean square position, and a front edge of the blade in a plan view having a substantially triangular protrusion. Consists of
The cross section in the radial direction of the blade has a concave curved shape toward the upstream side as it approaches the tip portion on the outer periphery of the blade.

According to this structure, the blade tip vortex generated on the suction surface near the tip of the blade due to the leakage flow from the pressure surface to the suction surface can be stably held by the concave curved portion. By promoting the generation of the vortex, the static pressure efficiency of the blower can be improved.

According to a second aspect of the present invention, the comparison t / c between the maximum thickness t and the chord length c at the root mean square position of the thick airfoil-shaped blade is set to 5 to 12%. According to this configuration, it is possible to achieve both low noise effect and high static pressure efficiency of the thick airfoil blade as compared with the thin airfoil having a constant thickness.

[Brief description of the drawings]

FIG. 1 is a plan view of an axial blower impeller according to an embodiment of the present invention.

FIG. 2 is a rotation locus diagram of an impeller of the same embodiment.

FIG. 3 is a radial cross-sectional view of the same embodiment.

FIG. 4 is a correlation diagram between a maximum thickness / chord length ratio and noise (A) according to the second embodiment of the present invention.

FIG. 5 is a comparison diagram of characteristic curves of the axial blowers according to the first and second embodiments of the present invention.

FIG. 6 is a schematic diagram showing an operation state of the axial blower according to the first and second embodiments of the present invention.

FIG. 7 is a rotation locus diagram of a conventional axial blower.

FIG. 8 is a sectional view of a conventional axial blower in a radial direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Axial blower impeller 2 Blade 3 Hub 4 Front edge 5 Trailing edge 6 Tip 7 Negative pressure surface 8 Pressure surface 9 Motor 10 Orifice

Claims (2)

[Claims] 1. On a rotational locus diagram of a plurality of thick and airfoil-shaped blades constituting an impeller, upstream so that only a leading edge of the blade has a maximum curvature near a root mean square position. The front edge on the plan view of the blade is formed of a straight line having a substantially triangular projection, and the cross section in the radial direction of the blade is A fan impeller having a curved shape that is concave toward the upstream side as approaching the outer periphery of the blade. 2. A ratio t / c of a maximum thickness t and a chord length c at a root mean square position of a thick airfoil-shaped blade is 5 to 2.
The blower impeller according to claim 1, which is 12%.