JPH10246200A - Impeller for axial blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain lightening of weight and reduction of a cost, without deteriorating durability and performance as a blade. SOLUTION: In an impeller for an axial blower constituted of an almost cylindrical hub and a plurality of blades 2, 2... protrusively provided in the periphery of the hub by an integrally molded product of synthetic resin, each blade 2 is formed in blade type shape having thickness in a section, also in this blade surface, many recessed parts 3, 3... in size capable of leaving air accumulated at rotation time are formed, weight of the blade 2 is markedly reduced, also so that a surface shape enveloping an outer end of the recessed parts 3, 3... can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impeller for an axial blower, which is made of a synthetic resin.

[0002]

2. Description of the Related Art Generally, when an axial blower used for an air conditioner (for example, an outdoor unit) is operated in an operation region other than a design point, air flow separation occurs on a blade surface, and as a result, aerodynamics is caused. Problems such as a decrease in performance and an increase in blowing noise occur. As a major problem in the blower having such a problem, suppression of separation of the air flow on the blade surface generated during operation can be cited.

As a method for solving the above-mentioned problem, a method of forming a blade 2 'into a blade-like shape having a thick cross section as shown in FIG. 6 has conventionally been adopted. With such a blade shape, even if the inflow angle to the blade 2 'changes,
Separation of the air flow on the blade surface is less likely to occur, and it is possible to solve the problems of reduced aerodynamic performance and increased blowing noise.

However, if the blade shape as described above is adopted, even if it is made of a synthetic resin, the weight of the blade must be increased, and the strength of the root of the blade 2 'withstands centrifugal force during high-speed rotation. There is a problem that it cannot be obtained. Further, the material cost during resin molding also increases.

[0005] To cope with the above-mentioned problems, there has been proposed a configuration in which one side of the blade is hollowed to reduce the thickness and a cover is attached to the hollowed portion via a rib (for example, Japanese Patent Application Laid-Open No. H11-157556). See JP-A-6-264898).

[0006]

However, in the case of such a structure as in the above-mentioned known example, it is difficult to completely discharge water when water enters the hollowed portion of the blade. Then, if water freezes inside, the blades may be damaged due to volume expansion.

[0007] The present invention has been made in view of the above points, without impairing the durability and performance as a blade.
It is intended to reduce the weight and cost.

[0008]

In the basic structure of the present invention, as a means for solving the above-mentioned problems, a substantially cylindrical hub 1 and a plurality of blades 2 protruding from the outer periphery of the hub 1 are provided.
In the impeller for an axial flow blower, which is constituted by an integrally molded product of a synthetic resin, each of the blades 2 is formed into an airfoil shape having a thick cross-section, A large number of recesses 3, 3,... Having a size capable of storing air are formed.

With the above-described configuration, the blade 2
The weight of the blade 2 can be greatly reduced, and the surface shape enclosing the outer ends of the concave portions 3, 3,... Can be secured, so that high strength and low cost can be achieved, and the wing-shaped blade 2 Aerodynamic performance and noise reduction performance can be ensured. In addition, even if water enters the recesses 3, 3,..., The blades 2 can be completely discharged because they are in the open state, so that the blades 2 do not break due to freezing or the like.

In the basic structure of the present invention, the recesses 3, 3,... May have a hexagonal cross section, a quadrangular cross section, or a circular cross section.

[0011]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

As shown in FIG. 1, the impeller for an axial blower includes a substantially cylindrical hub 1 and a plurality of blades 2, 2, 2 protruding from the outer periphery of the hub 1 made of synthetic resin. Each of the blades 2 has an airfoil shape having a thick cross section (see FIG. 3).

One surface of each of the blades 2 (for example, a suction surface 2)
2A and 3A, as shown in FIGS. 2 and 3, a large number of concave portions 3 having a size capable of storing air during rotation.
3 ... are formed.

The recesses 3, 3,... Basically have any shape as long as they can store air during rotation. For example, the recesses 3, 3,. That is, it can have a honeycomb shape (see FIG. 2), a rectangular cross-sectional shape (ie, lattice shape) (see FIG. 4), or a circular cross-sectional shape (see FIG. 5). . In the negative pressure surface 2 a of the blade 2, the front edge portion 4, the outer peripheral edge portion 5, the rear edge portion 6, and the inner peripheral edge portion 7 are left with a portion where a concave portion having a predetermined width is not formed. In particular, leaving a portion where no concave portion is formed in the front edge portion 4 and the outer peripheral edge portion 5 is to cope with a possibility that the inflowing air flow may be from multiple directions.

With the above-described structure, the blade 2
The weight of the blade 2 can be greatly reduced, and the surface shape enclosing the outer ends of the concave portions 3, 3,... Can be secured, so that high strength and low cost can be achieved, and the wing-shaped blade 2 Aerodynamic performance and noise reduction performance can be ensured. In addition, even if water enters the recesses 3, 3,..., The blades 2 can be completely discharged because they are in the open state, so that the blades 2 do not break due to freezing or the like.

In the above embodiment, the blade 2
Are formed on the negative pressure surface 2a of the blade 2, but are formed on the pressure surface 2b of the blade 2 (see FIG. 2).
Of course, or of course, the concave portions 3, 3... May be formed in both the suction surface 2a and the pressure surface 2b.

[0017]

According to the present invention, a substantially cylindrical hub 1 is provided.
And a plurality of blades 2, 2, 2 protruding from the outer periphery of the hub 1.
In the impeller for an axial flow blower, which is constituted by an integrally molded product of a synthetic resin, each of the blades 2 has a blade-shaped shape having a thick section, and air is stored on the blade surface during rotation. By forming a large number of recesses 3, 3... Of a size that can be placed, the weight of the blade 2 can be greatly reduced, and a surface shape enclosing the outer ends of the recesses 3, 3. Therefore, there is an excellent effect that the strength and the cost can be reduced, and the aerodynamic performance and the noise reduction performance of the blade-shaped blade 2 can be secured.

Moreover, even if water enters the recesses 3, 3,..., The blades 2 can be completely drained because they are in the open state, so that the blades 2 are not damaged due to freezing or the like. Disappears.

[Brief description of the drawings]

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

FIG. 2 is an enlarged front view of an essential part showing an example of an impeller for an axial blower according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a blade in an axial blower impeller according to an embodiment of the present invention.

FIG. 4 is an enlarged front view of an essential part showing another example of the impeller for an axial blower according to the embodiment of the present invention.

FIG. 5 is an enlarged front view of a main part showing another example of the impeller for an axial blower according to the embodiment of the present invention.

FIG. 6 is a sectional view of a blade in a conventionally known axial-flow fan impeller.

[Explanation of symbols]

1 is a hub, 2 is a blade, 2a is a suction surface, 2b is a pressure surface, 3
Is a recess.

Claims (4)

[Claims] 1. A substantially cylindrical hub (1), and the hub (1)
, A plurality of blades (2) protruding from the outer periphery of the axial flow blower are formed of an integrally molded product of a synthetic resin, wherein each of the blades (2) is: It features a thick airfoil shape in cross section, and a large number of recesses (3), (3),... That are large enough to hold air during rotation when formed on the blade surface. Impeller for an axial blower. 2. The impeller for an axial blower according to claim 1, wherein said recesses (3) have a hexagonal cross section. 3. The impeller for an axial blower according to claim 1, wherein the recesses (3) have a rectangular cross section. 4. The impeller for an axial blower according to claim 1, wherein the recesses (3) have a circular cross section.