JPH04259699A - Fan casing of blower - Google Patents

Abstract

PURPOSE:To heighten the sound absorbing effect and suppress the noise by forming a scroll part from porous plastic having sound absorbing property. CONSTITUTION:Prior to a molding process, a non-draughty side plate 2A is in advance inserted in a stationary die, and the cavity in dies is filled with a granular plastic material together with binder such as cellulose powder. The dies are heated, and the surfaces are melted, and thereby a scroll part 1 consisting of porous and draughty plastic is formed in a single piece with the periphery of the side plate 2A. At the open end opposite this side plate 2A, another side plate 2B having at the periphery a flange for joining 2a is secured in the same manner as a conventional fan casing. This heightens the sound absorbing effect, and reduces noises.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower used in an air conditioner or the like, and particularly to an improvement in the structure of a fan casing to reduce noise.

0002

2. Description of the Related Art As a conventional fan casing for an air blower, those shown in FIGS. 4 and 5 are known. In these figures, (A) is a fan casing, (1) is a scroll that covers the circumferential direction of the fan (not shown), (2A) (2B)
) are a pair of side plates that cover the fan in the axial direction, and are formed with flanges (2a) projecting inward to fit into the open ends on both sides of the scroll (1). (2
b) is an air suction port, and (3) is a hole opened in the outer circumferential wall of the scroll (1) to diffuse noise. A large number of holes are formed at equal intervals with the same size in a well-balanced manner, and the opening area is the same as that of the scroll ( It is formed so as to correspond to approximately 30% of the area of the outer peripheral surface of 1). (4) is a sound absorbing material made of a urethane foam material, and is pasted on the inner wall surface of the scroll (1) with an adhesive or the like.

[0003] Next, the operation will be explained. Noise generated within the fan casing (A) is absorbed by the sound absorbing material (4) inside the scroll (1), and is further diffused through a large number of holes (3). This equalizes the noise level and reduces the generated noise.

0004

[Problems to be Solved by the Invention] As described above, in the fan casing of a conventional blower, it is necessary to provide a large number of holes in the outer circumferential wall of the scroll, and in the axial direction of the fan, both sides are different from the scroll. Since it has to be constructed from a pair of side plates that are separate pieces, the number of parts and the number of man-hours required to assemble it increase, which poses problems in terms of cost and workability.

The present invention was made to solve the above-mentioned problems, and it is possible to easily process the scroll part, reduce the number of parts and assembly man-hours, and provide a blower fan with high productivity. The purpose is to provide a casing, and the purpose is to further reduce noise by having a higher sound absorption effect.

[0006]

[Means for Solving the Problems] In order to achieve the above object, a fan casing for an air blower according to the present invention comprises a scroll portion that covers the circumferential direction of the fan and a side plate that covers the axial direction of the fan. In the casing, the scroll portion is made of porous sound-absorbing plastic.

[0007] One of the suction side side plates can be integrally formed by insert molding in a mold,
In this case, it is preferable that the suction side side plate is made of an inserted non-porous material.

[0008] Furthermore, the scroll part and the side plate made of porous plastic with a lower porosity than the porous plastic of the scroll part can be integrally formed by die molding. Preferably, it is a non-porous material due to the change in filling efficiency.

[0009]

[Function] The fan casing of the blower according to this invention has the following features:
The scroll part made of porous plastic absorbs noise such as fan drive noise generated inside the fan casing. In addition, by integrally forming the scroll part and the side plate that covers the axial direction of the fan by mold insert molding, etc., we are able to reduce the number of parts and reduce the porosity of the side plate, making it air-free. This prevents air leakage in the direction of the fan axis.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a fan casing of a blower according to a first embodiment of the present invention. In the figure, (1) is a scroll part molded from porous and breathable plastic, and (2A) is a side plate made of a non-breathable material such as sheet metal that closes one side of the fan casing (A) in the axial direction. So, before molding, prepare the side plate (2A
) is inserted into a fixed mold (not shown), the mold cavity is filled with plastic granular material along with a binder such as powdered cellulose, and the mold is heated to melt the surface to create a porous and breathable material. A scroll part (1) molded from a certain plastic is integrally connected to the periphery of a non-ventilated side plate (2A). A side plate (2B) having a joining flange (2a) on the periphery is fixed to the open end opposite to the side plate (2A), similar to a conventional fan casing.

Another method of insert molding is to first mold the scroll part (1) using a plastic granular material, insert it into a mold, and then fill the mold cavity with ABS resin or polypropylene resin. By injection molding a thermoplastic resin such as, the scroll portion (1) molded from porous and breathable plastic and the periphery of the non-air permeable side plate (2A) are integrally joined.

FIG. 2 is a perspective view showing a fan casing of a blower according to a second embodiment of the present invention. In the figure, (
1) is a scroll part molded from porous and breathable plastic raw material, (2A) is a fan casing (
A) is a side plate whose porosity is reduced to such an extent that it is non-air permeable by changing the filling efficiency of blocking one side in the axial direction of A), and is formed integrally with the scroll part (1) by molding at the same time. For this molding, if the heating temperature of the mold (not shown) is made different, the part near the side plate is the hottest, and the mold cavity is filled with plastic granular material along with a binder such as powdered cellulose. The surface becomes molten to form a porous and breathable scroll part (1), and at the same time, an air-impermeable side plate (2A) whose surface in contact with the high-temperature mold is melted is formed integrally with this scroll part (1). At the open end opposite to the side plate (2A), there is a side plate (2B) having a joining flange (2a) on the periphery like a conventional fan casing.
) is fixed.

Next, the operation of the above embodiment will be explained. The noise generated within the fan casing (A) is absorbed by the ventilation holes in the scroll part (1) made of porous plastic. Since the side plates (2A) (2B) located in the axial direction of the fan casing (A) are made of non-ventilated material, air leakage is completely prevented. One side plate (2A) has a scroll part (1
) and molded into one piece, completely preventing air leakage that occurs at the boundary. However, since porous plastic has coarse particles, the scroll part (1) alone has low strength as a molded product, and there is a problem that it may break before the fan casing (A) is assembled. Therefore, when forming the scroll part (1) only with porous plastic, it is necessary to close one side surface (1A) as shown in FIG.
In this case, the scroll part (1) and the side plate (1A
) are molded with the same porous plastic at the same time, air leakage also occurs in the axial direction of the fan, so it is necessary to fit the side plate (2A) to the outer wall of the fan, and the parts This will not result in a reduction in points.

[0014] In the fan casing (A) of the present invention, preferably, the side plate (2A) is formed of an inserted non-porous material, or the side plate (2A) is formed of a non-porous material by changing the filling efficiency. This structure prevents air from leaking in the axial direction of the fan while reducing the number of parts. Of course, even when the scroll portion (1) is used as a single unit, there is no need to drill holes or attach sound absorbing materials such as urethane foam as in the past.

[0015]

[Effects of the Invention] As described above, according to the present invention, since the scroll portion is formed of porous sound-absorbing plastic,
It eliminates the need for conventional methods such as drilling holes and pasting urethane foam sound-absorbing material, and can achieve high soundproofing effects.

Furthermore, as claimed in claim 2, one of the suction side side plates covering the axial direction of the fan is integrally formed with the scroll portion by mold insert molding, thereby reducing the number of parts and assembly man-hours. quality, production costs are reduced,
By constructing the suction side side plate from a non-ventilated material, air leakage in the fan axial direction is prevented.

Further, as in claim 4, a scroll portion;
The side plate, which is made of porous plastic with a lower porosity than the porous plastic of the scroll part, is integrally formed with gold molding, reducing the number of parts and assembly man-hours, reducing production costs. Air leakage in the axial direction of the fan is prevented by constructing the plate with a non-porous material that changes the filling efficiency.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a fan casing of a blower according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a fan casing of a blower according to a second embodiment of the invention.

FIG. 3 is an explanatory diagram when the fan casing body is formed of porous plastic.

FIG. 4 is a perspective view showing a fan casing of a conventional blower.

FIG. 5 is an exploded perspective view of the fan casing.

[Explanation of symbols]

1 Scroll part 2A Side plate 2B Side plate 2b Air intake port

Claims (5)

[Claims] 1. A fan casing for a blower comprising a scroll portion that covers the circumferential direction of the fan and a side plate that covers the axial direction of the fan, wherein the scroll portion is made of porous sound-absorbing plastic. fan casing. 2. The fan casing for a blower according to claim 1, wherein one of the suction side side plates covering the axial direction of the fan is formed integrally with the scroll portion by insert molding of a mold. 3. The fan casing for an air blower according to claim 2, wherein the suction side side plate is made of an inserted non-porous material. 4. The scroll part and the side plate made of porous plastic having a lower porosity than the porous plastic of the scroll part are integrally formed by molding. Blower fan casing. 5. The fan casing for an air blower according to claim 4, wherein the porous plastic having a small porosity is a non-porous material by changing the filling efficiency.