JPH084694A - Blast fan and its manufacture - Google Patents

Abstract

PURPOSE:To make a blast fan lighter as a whole, shorten its molding cycle, restraining its deformation and warping during molding and maintain its strength by providing a relatively thicker blade, sectionally NASA-shape (double circular arc), to improve blasting performance and reducing blasting noise. CONSTITUTION:A blast fan is provided with a blade which has a skirt layer 7a on the surface side and a foamed layer 7b inside. In manufacturing the blast, fan, foaming agent is mixed into resin material to mold the blast fan so that the skin layer and the foamed layer can be formed on the surface side and inside of the blade, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower fan such as a turbo fan provided in an air conditioner and a method for manufacturing the same, and more particularly to a blade formed into a thick wall.

[0002]

2. Description of the Related Art For example, there is an air conditioner equipped with a ceiling-embedded indoor unit. The indoor unit accommodates a blower that draws in air from the heat exchanged chamber, exchanges heat with the heat exchanger, and blows air again into the room.

For the blower fan of this blower, a turbo fan having optimum blower characteristics is often selected because of the environment in which it is used as a ceiling-embedded type and there is a great demand for noise reduction.

The turbofan is formed in a horn shape from a boss portion fitted to the rotary shaft of the drive motor, and is formed into a horn shape from the boss portion, and the tip end portion is bent and formed in a direction orthogonal to the axis line of the boss portion. A main plate, a plurality of blades, one end of which is connected to the end face of the main plate, are provided at a predetermined interval from each other, and a suction ring which is laid across the other ends of these blades. It

As a material for forming such a turbo fan, of course, a resin material that is easy to mold and lightweight is selected. Specifically, AS-G made by mixing glass fiber fiber into resin material AS (acrylic styrene)
A PP-G material made by mixing glass fiber fibers into a material or a resin material PP (polypropylene) is often used.

In order to improve the air blowing performance and to reduce the air blowing noise, the blade is so-called NASA.
It is shaped to have a (double arc) shaped cross section. This blade has a relatively large wall thickness and has a cross-section blade substantially similar to the cross-section of an aircraft wing.

[0007]

It has been proved that a turbofan provided with blades having such a cross-section blade can improve the blowing performance and reduce the blowing noise. However, since the blade of the blade having the above-mentioned cross section has a relatively large wall thickness of at least 10 mm or more, a new problem in fan molding has occurred.

That is, since only the blade is thicker than the other parts, the cooling time after the resin material is heated and melted and poured into the mold to be molded is lengthened particularly in the blade.

Therefore, the molding cycle as a fan becomes longer than that of the conventional one provided with a thin blade, which adversely affects the productivity. In addition, the material used is bulky, which increases the weight of the turbofan as a whole, leading to an increase in cost.

Furthermore, since only the blade is thick and the other portions are thin, deformation and warpage occur at the connecting portion and the thin portion, which adversely affects the blowing performance.

In order to solve such a problem, for example, Japanese Utility Model Laid-Open No. 57-63997 discloses a technique for filling a hollow portion of a rotor with a lightweight filler, and Japanese Utility Model Laid-Open No. 58-113.
In Japanese Patent Laid-Open No. 900, a technique has been provided in which a foam resin is attached to a blade and a curable resin is applied to the surface of the foam resin to form a cured resin film.

[0012] According to these techniques, weight reduction can be obtained, but on the other hand, there is a drawback that productivity is poor and labor is required, and strength is still uncertain, and full adoption is not considered.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the ventilation performance and to reduce the ventilation noise, so-called NASA.
Assuming that a blade with a relatively thick wall is provided so as to have a (double arc) shaped cross section, the overall weight is reduced, the molding cycle is shortened, and deformation and warpage during molding are suppressed. An object of the present invention is to provide a blower fan that can maintain its strength and a manufacturing method thereof.

[0014]

In order to satisfy such an object, the blower fan of the first invention is a blower fan made of resin having a plurality of blades as claimed in claim 1.
The blade is characterized in that the surface side is a skin layer and the inside is a foam layer.

According to a second aspect of the present invention, there is provided a method for manufacturing a blower fan, comprising: a method for manufacturing a blower fan made of resin having a plurality of blades; A skin layer is formed on the surface side of the blade, and a foam layer is formed inside the blade.

Further, as a third aspect, in the blade according to the first and second aspects, the skin layer in a low foaming state is gradually changed from the surface side to the inside to a foaming layer in a high foaming state. Is characterized by.

As claim 4, claim 1 and claim 2
In order to obtain the skin layer and the foam layer in the above described blade, the foam material mixed in the resin material is characterized in that it is mixed by 1 to 5% by weight ratio with respect to the resin material.

Claims 1 and 2 are defined as Claim 5.
The above-mentioned resin material mixed with the foam material is characterized in that 10 to 25% by weight of the glass material fiber is mixed with the resin material.

Claims 1 and 2 are defined as claim 6.
The resin material mixed with the above-described foam material is AS (acrylic styrene). As a seventh aspect, the resin material mixed with the foam material according to the first and second aspects is PP (polypropylene).

[0020]

When a foam material is mixed with a resin material and molded, a blade having a relatively thick wall has a skin layer on the surface side and a foam layer on the inside, which shortens the cooling time during molding and reduces the thickness of other thin parts. Controls deformation and warpage.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. A turbofan as a molded finished product is configured as shown in FIGS. 1 and 2. That is, reference numeral 1 in the figure is a main plate. The main plate 1 has a boss portion 2 having a vibration isolation structure along the axis l.

From the outer periphery of the boss portion 2, a horn-shaped taper portion 3 is formed, and the tip of the taper portion is the axis l.
Is a circular tip portion 4 that is bent in a direction orthogonal to.

A plurality of ribs 5 are radially provided around the boss portion 2 which is the base end portion of the main plate 1 at predetermined intervals, and a plurality of cooling holes 6 are provided between these ribs. Is opened.

A plurality of blades 7, which will be described later, are integrally connected to the surface of the tip portion 4 of the main plate 1 on the side of the boss portion 2 at predetermined intervals. These blades 7 have a relatively thick-walled wing-like cross section, and are formed by inclining at a predetermined angle.

A suction ring 8 is integrally connected to the end surface of the blade 7 opposite to the tip 4 side. The suction ring 8 is formed to have the same outer diameter as the diameter of the tip portion 4 of the main plate, and has a horn shape in the inner diameter direction.

A plurality of projections 10 ... Are integrally provided on the outer peripheral surface of the suction ring 8 at a predetermined interval. Each of the protrusions 10 is provided facing the connecting position of the blade 7, has a semicircular cross section, and has a predetermined width,
It projects in the radial direction. These projections 10 are useful when molding a turbo fan.

A turbo fan is formed in this way,
The boss portion 2 is fitted to a rotating shaft of a motor (not shown) here, and the rotation of the rotating shaft serves to blow air. Next, a method for manufacturing a turbo fan will be described.

In this turbofan, AS (acrylic styrene) which is a synthetic resin material is selected as a base material. Then, a glass fiber fiber is added to the AS material in a weight ratio of 10
-25% is mixed to obtain an AG-S material. The AG-S material mixed with a foaming material in a weight ratio of 1 to 5% (preferably 2%) is a raw material for the fan.

Such raw material materials are put into a mold of a molding machine and injection molding is performed. In the injection molding machine, a fixed-side mold is provided on the main body of the molding machine, and a first movable-side mold, a slide mounting mold, and a second movable-side mold are respectively provided with respect to the fixed-side mold. It is slidably combined in the axial direction.

A cavity is slidably combined with the first movable mold in the radial direction, and a core is slidably combined with the slide mounting mold. The holding mold is axially slidably combined with the second movable mold.

A turbofan-shaped space is formed between these molds, and the AG-S material mixed with the foam material is injected into this space to radiate heat and solidify. The main plate 1 part is molded by the fixed mold and the first movable mold, and the blade 7 part is molded by the cavity, the core, and the second movable mold, and the second movable mold and the holding member are held. The suction ring 8 portion is molded with a mold.

As shown in FIG. 3, the blade 7 has a so-called NASA blade cross-sectional shape, and the maximum thickness portion has a wall thickness of about 13 mm. Then, the raw material material described above is selected and injection-molded to obtain a cross-sectional state as shown in FIG.

That is, the foam material is easily foamed in the central portion of the blade 7, and the foaming degree is reduced over the surface side. On the most surface side, partly due to the cooling effect of the mold,
It becomes a hardened layer with almost no foaming.

To explain further, the surface side of the blade 7 is
The mold makes it difficult for the nuclei of the foam material to grow, resulting in a low foaming state. However, the cooling effect received from the mold over the inside gradually decreases, and the conditions under which the core of the foam material easily grows and the degree of foaming increases. In the central part, since it is not affected by the mold at all, the core of the foam material grows sufficiently and becomes the most highly foamed state.

The layer hardened in a low foaming state on the surface side of the blade 7 thus obtained is called a skin layer 7a, and the most foamed layer in the central portion is called a foaming layer 7b. From the foamed state described above, these skin layers 7
The boundary between a and the foam layer 7b cannot be clearly set.

On the other hand, the blade 7 constituting the turbofan
Since the horn-shaped main plate 1, the ribs 5, the suction ring 8 and the like, which are members other than the above, are thin-walled, foaming nuclei do not grow on the surface side and inside even if the raw material is mixed with foaming material. , Make a full thickness.

After all, although the turbofan is provided with the thick blade 7, the molding cooling time of the blade is shortened and the molding cycle can be shortened. Even if the surface side of each blade 7 is a hard skin layer 7a, since it can be formed into a foam layer 7b that foams the inside, compared with the conventional blade having a completely thick wall, It can be reduced.

Further, the strength of each blade 7 gradually increases from the inside to the surface side due to the degree of foaming, and the strength of the entire blade can be maintained. In addition to such a blade 7, since the foaming does not occur in the components other than the blade, the mechanical strength of the entire turbofan is
It is possible to obtain the same characteristics as conventional ones, in which no foam material is mixed.

In particular, the temperature difference between the thick blade 7 and the thin main plate 1 at the time of molding can be made small. Therefore, the warp and deformation of the main plate 1 can be suppressed, and the vibration of the fan as a whole can be balanced and blown. Get a reduction in.

The foaming material mixed in the AS-G material as a raw material was set to a weight ratio of 1 to 5% (preferably 2%) because many prototypes were manufactured and various experiments were conducted. It depends on the result.

By the way, if the weight ratio is 1% or less,
The foaming inside the blade is insufficient, and each characteristic is almost the same as that of the resin material alone. Further, when the weight ratio is 5% or more, when the fan is taken out of the mold, the foaming continues in the blade central part, and the blade part expands, so that the stable shape cannot be maintained.

10% to 25% by weight of the resin material
By mixing the glass fiber of (1), the strength as a base material can be increased, and the strength can be further increased by matching the mixing amount of the foam material.

In the above embodiment, AS (acrylic styrene) was selected as the resin material, but it is not limited to this, and for example, PP (polypropylene).
Even if the same amount of glass fiber fiber is mixed instead and the same amount of foam material is mixed, the same effect as the AS material can be obtained.

As shown in FIG. 4 (A), even if a so-called propeller fan is used as the blower fan, the same effect can be obtained under the same conditions. That is, the figure shows only one blade 17 that constitutes a propeller fan. A cross section BB of the blade 17 along the circumferential direction is formed into a wing shape in cross section as shown in FIG. Therefore, the blade 17 has a partially thick cross-sectional shape.

AS (acrylic styrene) or PP (polypropylene) which is a synthetic resin material is selected as a base material, glass fiber fibers are mixed in a weight ratio of 10 to 25%, and further a weight ratio of 1 to 5% (preferably, 1 to 5%). 2%) of the foamed material is mixed to form a raw material, which is put into a mold of a molding machine and injection molded.

Therefore, the surface side of the blade 17 is in a low foaming state because it is difficult for the core of the foam material to grow by the mold.
The condition is such that the core of the foam material easily grows inside, and the degree of foaming increases. In the central part, since it is not affected by the mold at all, the core of the foam material grows sufficiently and becomes the most highly foamed state.

A layer hardened in a low foaming state on the surface side of the blade 17 thus obtained is used as a skin layer 17.
The most highly foamed layer in the center is called the foam layer 17b.
Call. The boundary between the skin layer 17a and the foam layer 17b cannot be clearly set from the foamed state described above.

On the other hand, since the rib portion 18, which is a member other than the blade 17 which constitutes the propeller fan, is thin, even if it is a raw material mixed with a foam material, foam nuclei grow on the surface side and inside thereof. Without doing, make a full thickness.

With such a propeller fan, it is possible to obtain exactly the same working effects as the turbofan described above. Returning to the turbo fan again, as shown in FIGS. 5 and 6, a rectangular side surface rectangular hole 6a is formed on the side surface of the horn-shaped tapered portion 3 so as to face the predetermined cooling hole 6.
To open.

Specifically, the side surface rectangular holes 6a are provided at 90 ° intervals from each other by facing the cooling holes 6 arranged every other one of the cooling holes 6 arranged radially from the center. To be

Of these side surface rectangular holes 6a, 180 °
The side surface rectangular holes 6a, 6a at the spaced positions communicate with the cooling holes 6, 6 via the communication grooves 6b, 6b, respectively. Therefore, the substantially horn-shaped tapered portion 3 is divided into two.

On the other hand, the gate 20 for injection molding is radially set at a position intersecting with the extended position of the center line of the cooling hole 6 on the inner diameter side of the main plate 1, as shown in FIG.
From this, the weld line (dividing line) W generated by injection molding becomes a line connecting the center of the rib 5 and the tip of the blade 7, and does not intersect the cooling hole 6 and the side surface rectangular hole 6a. Absent.

As described above, since the weld line W does not intersect the cooling hole 6 and the side surface rectangular hole 6a at all, the decrease in strength can be suppressed to the minimum. In addition, the pair of side surface rectangular holes 6a and the communication groove 6 located at the positions facing each other.
By b and the cooling hole 6, the upper part of the horn-shaped tapered portion 3 is divided into two in the circumferential direction, and the natural vibration can be removed.

That is, since the horn-shaped tapered portion 3 has a natural vibration peculiar to the horn shape, even if the vibration transmission from the motor or the like is reduced by the vibration-proof rubber, the natural vibration due to the horn shape is amplified. , There was noise.

Therefore, as described above, the pair of side surface rectangular holes 6
By dividing the upper part of the horn-shaped taper portion 3 into two in the circumferential direction by a, the communication groove 6b, and the cooling hole 6, it is possible to eliminate the natural vibration peculiar to the horn that occurs in the circumferential direction.

According to the measurement results, the noise at the frequency of the standing wave in the circumferential direction due to the natural vibration was reduced by 5 dBA (720 HZ). Further, by providing the side surface rectangular hole 6a on the side surface of the horn-shaped taper portion 3, the area for radiating and expanding the magnetic vibration from the motor can be reduced in addition to the above-described vibration-proof effect, so that the noise is further reduced. Side rectangular hole 6a and communication groove 6b
Due to the existence of the above, the cooling hole 6 itself is enlarged, and the cooling efficiency for the motor can be improved.

[0057]

As described above, the first aspect of the present invention is a blower fan equipped with a blade having a skin layer on the front side and a foam layer on the inner side. Therefore, a so-called NASA (double arc) is provided.
While being equipped with a relatively thick blade so as to have a shape cross section, overall weight reduction can be obtained, and improvement of air blowing performance,
Blower noise can be reduced, and deformation and warpage during molding can be suppressed to maintain strength.

The second invention is a method for manufacturing a blower fan in which a foam material is mixed with a resin material and molded, a skin layer is formed on the surface side of the blade, and a foam layer is formed inside the blade. In addition to shortening the cycle, the deformation and warpage at the time of molding can be suppressed to maintain the strength, and the molded blast fan is lighter overall, improving the blast performance and lowering the blast noise. And other effects.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a molded turbo fan showing an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of a turbo fan of the embodiment.

FIG. 3 is a diagram illustrating a cross-sectional configuration of a blade according to the embodiment.

FIG. 4A is a plan view of a main part of a propeller fan, which is a blower fan of another embodiment. FIG. 3B is a diagram illustrating a cross-sectional configuration of a blade.

FIG. 5 is a partially cutaway perspective view of a turbo fan according to another embodiment.

FIG. 6 is a plan view of the turbo fan according to the embodiment.

[Explanation of symbols]

7 ... Blade (of turbo fan), 7a ... Skin layer, 7
b ... foam layer, 17 ... blade (of propeller fan), 1
7a ... Skin layer, 17b ... Foam layer.

Claims (7)

[Claims] 1. A blower fan made of resin having a plurality of blades, characterized in that the blower fan has a skin layer on the front side and a foam layer inside. 2. A method for manufacturing a blower fan made of resin having a plurality of blades, wherein a foam layer is mixed with a resin material to form a skin layer on the surface side of the blade, and the inside of the blade is formed. A method for manufacturing a blower fan, which comprises forming a foam layer on the inner surface. 3. The blower fan according to claim 1, wherein the blade gradually changes from a skin layer in a low foaming state to a foaming layer in a high foaming state from the surface side to the inside. 2. The method for manufacturing a blower fan according to 2. 4. The foam material mixed in the resin material in order to obtain a skin layer and a foam layer in the blade is mixed in an amount of 1 to 5% by weight ratio with respect to the resin material. And a method for manufacturing the blower fan according to claim 2. 5. The blower fan according to claim 1, wherein the resin material mixed with the foam material contains glass fiber fibers in a weight ratio of 10 to 25% with respect to the resin material. A method for manufacturing the described blower fan. 6. The resin material mixed with the foam material is AS
(Acrylic styrene).
A blower fan according to claim 2 and a method for manufacturing a blower fan according to claim 2. 7. The resin material containing the foam material is PP
(Polypropylene) The blower fan according to claim 1, and the method for producing a blower fan according to claim 2.