JPH06156054A - Duct structure for low noise air conditioning - Google Patents

Abstract

PURPOSE:To decrease noise after satisfying the condition as a duct that necessary air does not leak, by providing an opening at least at a part of a duct body and mounting and mounting in one body with the duct a soft urethane foam sheet material, in which film is laminated on its one side. CONSTITUTION:A soft urethane foam sheet material 3, in which film 8 is laminated on one side, is mounted in form of one body with the duct via an adhesive or pressure sensitive adhesive, to the opening of a duct body 2, which is formed by blow-molding or injection molding-polyethylene resin or polypropylene resin and thus the duct structure is produced. This duct structure is used by being attached to an air conditioner unit for an automobile.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioning duct structure for automobiles and other vehicles.

[0002]

2. Description of the Related Art Conventionally, a blow molding of a thermoplastic resin such as polyethylene is used.

[0003]

In the case of blow molded products,
There is no sound absorption effect because the surface of the molded product totally reflects the sound, and the noise generated by the blower sound of the air conditioner and the air flow is disturbed as it enters the room through the duct, so it is quiet inside the room Is damaged.

[0004]

As a result of studies to solve such conventional problems, it is preferable that a part of the duct is made of a porous material having a sound absorbing property, but air leaks. Since it does not fulfill the function as a duct, it was found that a soft urethane foam sheet material with a film laminated on one side meets this condition. That is, the present invention provides an opening in at least a part of the duct body,
The air-conditioning duct structure is characterized in that noise can be reduced by mounting and integrating a soft urethane foam sheet material having a film laminated on one side at the opening.

Here, the opening provided in the duct body means
It means an opening provided at any position other than the original air inlet and outlet, and at least a part means one or more places. As shown in FIG. 1, the air-conditioning duct according to the present invention has a structure in which the urethane foam sheet material with film 3 is integrally mounted in the opening of a duct body 2 made of a thermoplastic resin molded product. The duct body 2 made of a thermoplastic resin molded product is manufactured by a method in which a part of blow molded polyethylene resin, polypropylene resin, or the like is opened, or a shape having an opening is directly formed by injection molding. Then, as shown in FIG. 2, the flexible urethane foam sheet material 3 having a film laminated on one side in the opening 1 of the duct body 2 is adhesive with the surface of the film 8 outside and the surface of the flexible urethane foam sheet 7 inside. Alternatively, it is attached with an adhesive or the like to manufacture the air conditioning duct structure of the present invention.

The flexible polyurethane foam sheet 7 having a film laminated on one side has a density of 10 to 80 kg /
m3, preferably 20 to 50 kg / m3, the air permeability is
5ft3 / min or less, preferably 1.5ft3 / min or less (DO
A flexible polyurethane foam sheet according to the W method) is preferably used. The sound absorption characteristics change depending on the air permeability, and with respect to noise of 2000 Hz or less, which is usually a problem with outflow noise from ducts, the sound absorption characteristics having a low air permeability as described above can be obtained. Further, the thickness of the polyurethane foam sheet is preferably thick from the viewpoint of sound absorption characteristics, but it is desirable to secure 5 mm or more even if there is a space limitation. Examples of such a urethane foam include urethane foam that is generally used as a sound absorbing / vibrating material in various fields, and one that is impregnated with an asphalt material and post-treated can also be used.

As a method for laminating the film 8, a thermoplastic resin film such as polyvinyl chloride, polypropylene or polyethylene, a urethane film or the like is used, which is adhered to the flexible urethane foam sheet 7 through an adhesive, or vinyl acetate. , Various resins such as acrylic resin, urethane resin, rubber resin, and silicone resin are applied on the surface of the flexible urethane foam sheet 7 and then dried and cured to form a film layer, or a flame is formed on the urethane foam surface. It is also possible to form a film layer by uniformly compressing the surface of the film after melting by applying and stretching it thinly. Further, when the duct composed only of the resin molded product and the duct structure equipped with the urethane foam sheet material of the present invention were attached to an actual vehicle and the amount of air blown out from the outlet was compared by an air flow meter, it was found to be 25 .1 L /
While the latter is 24.6 L / sec, almost no air leakage is observed.

[0008]

As described above, the duct structure of the present invention is one in which an opening is provided in at least a part of the duct body, and a flexible urethane foam sheet material having a film laminated on one side is attached and integrated in the opening. Therefore, the reflection of sound waves at that portion is significantly reduced. Since the film is laminated on one surface of the flexible urethane foam sheet, it is possible to adjust the air permeation amount and the thickness of the foam sheet.
In addition, a soft urethane foam sheet material with a film laminated on one side that can be a sound absorbing material can be selectively placed and installed at a position where noise reduction of the duct main body is expected to be reduced, and the installation can be done from the outside. It is easily possible.
Moreover, since the flexible urethane foam sheet material is flexible, it can be easily mounted even in a complicated shape.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described with reference to FIG. A duct structure in which a flexible urethane foam sheet material 3 having a film laminated on one surface is attached and integrated through an adhesive or a pressure-sensitive adhesive to an opening 1 of a duct body 2 formed by blow molding or injection molding of polyethylene resin or polypropylene resin. Body 4 is manufactured. This duct structure 4 is attached to an air conditioner unit 5 of an automobile for use. At this time, the noise emitted from the duct outlet is measured by the sound level meter 6 (JIS C 1502) and is shown by the A characteristic, and 1/3 octave analysis is performed and it becomes as shown in Fig. 4 when compared with the duct of resin molded product only. . As a second example,
Blow molding is performed using polyethylene resin to manufacture the duct body 2 as shown in FIG. About 100x in the center of this
The opening 1 is provided with a size of 250 mm. 9m thick
A foam sheet material 3 having a film layer formed by applying a urethane-based resin on one side of a soft urethane foam sheet having a specific gravity of 0.025 and a permeability of 0.8 ft3 / min, and then forming a film layer is formed in the opening 1 Then, the duct structure 4 is formed by integrally bonding the two with a thermoplastic rubber-based hot melt adhesive. This is attached to an automobile air conditioner and used as an air conditioning duct. As a result, the noise level reducing effect as shown in FIG. 5 can be obtained as compared with the conventional thermoplastic resin duct. In FIG. 5, the vertical axis represents a value obtained by subtracting the noise level when the duct structure of the present invention is used from the noise level when the conventional duct is used, and the horizontal axis represents the noise reduction amount in decibels for each frequency. It is represented by (dB).

[0010]

As described above, according to the present invention, an opening is provided in at least a part of the duct body, and a flexible urethane foam sheet material having a film laminated on one surface is attached to the opening and integrated. Therefore, it is possible to reduce the noise while satisfying the condition that the air required for the duct does not leak, so the noise level entering the room through the duct is reduced and the quietness of the room is greatly improved. be able to. Further, the soft urethane foam sheet material having a film laminated on one surface can be arranged and mounted at an arbitrary position where the noise reduction effect of the duct body can be expected, and the mounting can be easily performed from the outside. Further, since the sheet material in which the film is laminated on one surface of the flexible urethane foam sheet is used, the amount of air permeation and the thickness of the foam sheet can be adjusted.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an air conditioning duct structure of the present invention.

FIG. 2 is a view showing an example of a method of mounting a flexible urethane foam sheet material having a film laminated on one surface.

FIG. 3 is a diagram showing an example of a method for manufacturing an air conditioning duct structure of the present invention.

FIG. 4 is a noise level comparison diagram by A characteristic, 1/3 octave analysis of the duct structure of the present invention and a conventional duct.

FIG. 5 is a comparison diagram of noise reduction rates of the duct structure of the present invention and a conventional duct.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Opening part 2 ... Duct main body 3 ... Soft urethane foam sheet material with a film laminated on one side 4 ... Duct structure 5 ... Air conditioner unit 6 ... Sound level meter

Claims (1)

[Claims] 1. An air conditioning duct characterized in that at least a part of a duct body is provided with an opening, and a soft urethane foam sheet material having a film laminated on one surface is attached to and integrated with the opening to reduce noise. Structure.