JP2007240948A - Noise reduction device and blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise reduction device in which noise is reduced with a simple structure by fabricating a cover without adding a reinforcement rib, and in which it is acoustically felt that noise is further reduced by making generated resonance frequency higher. <P>SOLUTION: The noise reduction device includes a casing which is composed of one or more plates for covering a noise source, and the casing has an approximately closed structure connected with the plates, and a noise insulating plate in which an arbitrary curvature is totally or partially provided on at least one face of the plates so as to be swelled to outside or inside. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a noise reduction structure, and reduces sound emission generated from a noise source using a rotating body such as a motor and vibration sound from a casing covering the noise source.

  In a conventional noise reduction device, noise in the propagation path can be reduced by providing a Helmholtz resonator in the path of the sound generation path from the noise generation location (see, for example, Patent Document 1). Moreover, in the conventional noise reduction apparatus, the main body casing that covers the fan is provided with reinforcing ribs to increase the strength and improve the vibration characteristics (see, for example, Patent Document 2).

JP 2004-25918 A (Page 7, FIG. 1) JP 2006-3011 A (page 14, FIG. 1)

  Conventional noise reduction devices have been effective in reducing the specific frequency of noise that matches the resonance frequency for canceling noise and the resonance frequency of this resonance space, but they do not match the resonance frequency of the resonance space. Therefore, it is difficult to reduce noise in a wide frequency band. In addition, since it is necessary to provide a resonance space structure in the noise propagation space, the volume of the resonance space changes due to accumulation of dust and the like in the resonance space in a housing space that requires an air passage such as a duct ventilation fan. As a result, there has been a problem that the noise level attenuation effect has disappeared, and as a result, it has been difficult to apply it to the reduction of noise components contained in air passages such as duct ventilation fans. In addition, since it is necessary to form a resonance space structure, a member for creating a space is necessary, which causes a problem of high device production cost for noise reduction. In addition, the duct ventilation fan is equipped with a fan motor for obtaining a large air volume in order to efficiently exhaust and intake air, and the inside of the housing is caused by vibration noise generated by the fan motor and air sucked by rotation of the fan motor. In addition to the noise generated by the air and the vibration of the case that occurs when the air fluid collides with the case of the duct ventilation fan, noise with various frequency characteristics is generated. The resonance type noise reduction device that reduces the components has a problem that it is difficult to cope with all noises.

  In another conventional noise reduction device, in order to reduce motor noise of a blower such as a duct ventilation fan, a radiated sound from the noise source is reduced by providing a cover surrounding the noise source. In particular, a blower such as a duct ventilation fan generates a vibration sound due to a collision with a side surface of the cover when a large amount of air flows through the cover. The cover that surrounds the noise source is made of a steel plate of about 1 mm, so the strength is insufficient. To increase the strength, the damping material, etc. is fixed, and the thickness of the material itself is increased due to the mass law. There was a problem that the weight of itself increased. As an example, reinforcing ribs are attached to the cover to increase rigidity and prevent vibration noise, thereby improving rigidity and vibration characteristics. Installation of the reinforcing rib has a problem that it takes time to prepare the reinforcing rib, process the mounting surface, and attach the reinforcing rib, and further increases the material cost of the reinforcing rib.

  The present invention solves such problems, reduces noise with a simple configuration by processing the cover without adding a reinforcing rib, further increases the generated resonance frequency, and further reduces noise on human hearing. The object is to obtain a felt noise reduction device.

  The second purpose is to obtain a blower that can effectively reduce noise with a simple configuration, and that the generated resonance frequency moves to a higher frequency so that the human auditory senses that the noise is further reduced. Objective.

A noise reduction device according to the present invention includes a noise source using a rotating body such as a motor, a casing made of one or a plurality of plates that fix the noise source and cover the noise source, and the casing includes: A structure in which the plate material is coupled and substantially sealed is provided, and at least one surface of the plate material is provided with a noise shielding plate in which an arbitrary curvature radius is provided entirely or partially so as to bulge outward or inward. .

  The present invention relates to a noise reduction structure, and reduces sound emission generated from a noise source using a rotating body such as a motor and vibration sound from a casing covering the noise source. In the noise reduction apparatus according to the present invention, noise is reduced by using a noise shielding plate having a curvature made of at least one of metal or resin on at least one surface of a casing covering a noise source using a rotating body. To reduce. Furthermore, the generated resonance frequency is increased to further reduce noise on human hearing. Further, since the configuration of the noise reduction device is simplified, the weight of the product housing can be reduced.

Embodiment 1 FIG.
A preferred embodiment of a noise reduction device according to the present invention will be described below with reference to FIGS. FIG. 1 is a device mounting schematic diagram showing a blower (duct ventilation fan) used in a ceiling or the like to which a noise reduction device 10 according to Embodiment 1 is applied. The blower 2 is generally a casing or a muffler box (housing), and surrounds all six surfaces of the left surface 3, the right surface 4, the upper surface 5, the bottom surface 6, the front surface 7, and the rear surface 8 with at least one plate material such as metal or resin. It has been broken. The joining method of each surface is bonded (configured or molded) by screwing, caulking, bonding, welding, or the like, and a substantially sealed structure is obtained. The dimensions are the top surface 5 and the bottom surface 6: 390 mm × 520 mm, 1 mm thickness, the left surface 3 and the right surface 4: 320 mm × 520 mm, 1 mm thickness, and the front surface 7 and the rear surface 8: 320 mm × 390 mm, 1 mm thickness. An exhaust duct 21 and an intake duct 20 are connected to a part of the front surface 7 and the rear surface 8 (duct diameter φ200, thickness 1 mm), respectively. FIG. 2 shows the inside of the duct ventilation fan 2 configured as described above. As a fan of the duct ventilation fan 2, for example, a sirocco fan 11 is mounted on the bottom surface 6, and air (air) etc. 12a, 12b sucked from the intake duct 20 connected to the rear surface 8 of the duct ventilation fan 2 as the fan motor rotates The air is sucked from both sides into the sirocco fan 11 along the left surface 3 and the right surface 4 of the muffler box, and air (air) 12c is discharged from the rear of the sirocco fan 11 and discharged to the outside from the exhaust duct 21 connected to the front surface 7. Is done.

  The amount of air blown from the duct ventilation fan used in this example is about 800 cubic meters / h. The air is sucked from the intake duct 20 and discharged from the exhaust duct 21.

  In the path from inhalation to discharge, the left surface 3 which is a part of the member constituting the casing has an arbitrary curvature radius R, and is a semi-cylindrical noise insulation board (hereinafter referred to as “curvation insulation board”) 30. By forming (FIG. 3), the strength (rigidity) increases. The curvature sound insulation plate 30 collides with the fluid sound generated by the inflow of the air 12a sucked from the intake duct 20 that has been transmitted from the inside of the housing to the outside of the housing and the housing member of the duct ventilation fan due to the improvement in rigidity. The vibration noise generated by the is reduced and the noise is reduced. When the curvature sound insulation plate 30 swells outward, the tube wall resistance of air on the left surface 3 side is reduced, and vibration noise is further reduced. Although the case where the curvature sound insulation board 30 swells outside was described, also when the curvature sound insulation board 30 swells inside, it has a noise reduction effect by the improvement in rigidity.

The curvature sound insulating plate 30 (thickness 1 mm) is a joint for increasing the rigidity of the curvature surface portion 31 and the plate material joint portion 32 for forming in the box of the housing, and the end portion of the curvature surface portion 31 and the plate material joint portion 32. It is comprised with the material 33 (FIG. 3 (A) (B)). FIG. 3A shows a case where a curved surface protrudes outside the housing, and FIG. 3B shows a case where the curved surface protrudes inside the housing. 3 (A) and 3 (B), the bonding material 33 for increasing the rigidity is composed of the bonding material 33 for increasing the rigidity of the joint portion 32 of the plate material at the concave end of the curvature surface portion 31. However, the same effect can be obtained even if the convex end portion of the curvature surface portion 31 is composed of the binding material 33 for increasing the rigidity of the joint portion 32 of the plate material (not shown).

  The curvature sound insulation plate 30 used in the casing of this example uses at least one plate material such as metal or resin. The molding method is press or injection with a mold.

  Next, the operation of the present embodiment will be described. The curvature sound insulation plate 30 and the joint portion 32 molded as described above are bonded or joined together and fixed firmly (hereinafter referred to as “completely fixed”) by screwing, caulking, further bonding or welding. A casing of the duct ventilation fan 2 which is a provided box is formed. Due to the complete fixing, there is no minute frictional movement such as sliding at the joint 32. As described above, by completely fixing the periphery of the curvature surface portion 31, the resonance point generated on the flat surface moves to a higher frequency, and the vibration mode generated on the flat surface becomes the split vibration mode. The large vibration of the plate itself that occurred on the flat surface can be damped. For this reason, the vibration of the housing surface generated by the air sucked from the air intake duct 20 colliding with the inner wall surface (structure) of the housing of the duct ventilation fan formed in the conventional flat surface state. Can be attenuated. In addition, since the curvature surface portion 31 does not vibrate because the vibration (vibration mode) is completely fixed by the joint portion 32, the curvature surface portion 31 does not vibrate. Therefore, it is possible to prevent the sound radiation accompanying the fluid generated inside the casing from leaking to the outside of the casing.

FIG. 5 shows the noise characteristics (solid line) of a conventional duct ventilation fan composed of a flat housing surface measured by a frequency analyzer at a distance of 1.5 m perpendicularly from the curvature surface portion 31 and the curvature sound insulation plate by the noise reduction device according to the present invention. The comparison result of the noise characteristic (dotted line) of the constructed duct ventilation fan is shown. In FIG. 5, the noise characteristic (dotted line) of the duct ventilation fan constituted by the curvature sound insulation board by the noise reduction apparatus according to the present invention has an effect of reducing noise at all frequencies of the noise characteristic. In addition, there is an effect that the noise is lowered on human hearing when the frequency of the peak portion (resonance frequency portion) in the conventional noise characteristics moves high and attenuates. (An example is shown in FIG. 5A → B)

The relationship (FIG. 4) of the curvature radius R, the curvature radius width L, and the curvature radius height H of the curvature sound insulation plate 30 of the noise reduction device 10 used in the measurement is expressed by the following equation.
R = L ² + H ² / 2H ---- Formula (1)
Although the curvature radius R and the curvature radius height H obtained by the above formula (1) are values of an example in which the curvature sound insulating plate 30 is effective as a noise reduction device, the curvature radius R is smaller and the curvature radius is higher. The same effect is obtained when the height H is increased.

The blower (duct ventilation fan) configured by the noise reduction device of the present invention has an effect of attenuating noise in the entire band because the vibration sound due to the vibration of the surface and the transmission of the radiated sound inside the housing are attenuated.

Embodiment 2. FIG.
In the first embodiment, no reinforcing material or the like is provided in the concave portion of the curvature surface of the curvature sound insulating plate 30. However, as shown in FIG. 6A, for example, a steel rib (solid side) 35 (thickness 2 mm). ) Is added as a four-sheet reinforcing material, the rigidity of the sound insulation board 30 is further improved. As shown in FIG. 5B, the rib 35 is bonded (adhered or welded, etc.) to the curvature sound insulating plate 30 at a joint surface of a plurality of points by, for example, a bonding material 33 of arc welding. The addition of the ribs 35 further increases the rigidity of the curvature sound insulating plate 30 and attenuates the transmission of vibration sound due to surface vibration and radiated sound inside the housing, thus increasing the effect of noise attenuation in the entire band. In the second embodiment, four ribs 35 are used as reinforcing members in the vertical direction. However, if one or a plurality of ribs 35 are provided, there is an effect. . If the thickness is effective as a reinforcing material, the same effect can be obtained at any thickness. If the material is not steel but at least one of metal or resin is used, the same effect can be obtained. The curvature sound insulation plate 30 reinforced by the ribs 35 has the same effect whether the protruding surface is on the inside or outside of the housing.

As shown in FIG. 7A, when a concave portion reinforcing member 36 formed of at least one material such as metal or resin having substantially the same shape as the curvature surface is added to the concave portion of the curvature noise insulating plate 30, the rigidity of the curvature noise insulating plate 30 is increased. Is further improved. The recessed portion reinforcing member 36 is bonded (adhered or welded) to the curvature sound insulating plate 30 at a plurality of joint points by spot welding, for example. The addition of the concave reinforcing member 36 further increases the rigidity of the curvature sound insulation plate 30 and attenuates the transmission of vibration sound due to surface vibration and radiated sound inside the housing. Go up. In the above-described example, the example in which bonding is performed at a plurality of joint points by spot welding has been described. Further, as shown in FIG. 8A, the same effect can be obtained by adding a convex reinforcing member 37 formed of at least one material such as metal or resin having substantially the same shape as the curvature surface to the convex portion of the curvature sound insulating plate 30. There is. The curvature sound insulation plate 30 in FIG. 7 (A) and FIG. 8 (A) has been described in the case where the curvature sound insulation plate 30 swells outward, but the curvature sound insulation plate 30 in FIG. 7 (B) and FIG. 8 (B). Even when the swells inward, it has a noise reduction effect by improving the rigidity. Although the example which attached the reinforcement member 36 or the convex part reinforcement member 37 to the curvature sound insulation board 30 was demonstrated, even if it attaches the reinforcement member 36 and the convex part reinforcement member 37 to the curvature noise insulation board 30, it has the same effect.

Embodiment 3 FIG.
In the present invention, the case where the curvature sound insulation plate 30 is mounted on only one surface has been shown, but the same effect can be achieved even when mounted on all surfaces other than the surfaces to which the ducts 20 and 21 are connected (FIG. 9). .

Further, FIG. 10 shows an example in which the structure of the curvature surface portion of the curvature sound insulating plate 30 is formed into a dome shape 50. As shown in the figure, even if it is formed in a dome shape, the same sound insulation and vibration noise reduction effects can be exhibited. FIG. 11 shows a cross-sectional view taken along the line AA ′ of an example of the dome shape 50. A vertex C in the AA ′ cross section indicates a vertex of the dome portion, and the slope D portion is formed by a plane. Although the slope D portion is formed as a flat surface, the same effect can be obtained even if it is formed as a curved surface and bulges outward or inward. FIG. 12 shows a cross-sectional view taken along the line BB ′ of an example of the dome shape 50. The vertex E in the BB ′ cross section indicates the vertex of the semi-cylindrical portion, and the slope D portion is formed by a plane. The curved surface portion including the vertex E inside the broken line F swells outward, but the same effect can be obtained if it swells inward. The slope F portion is formed as a flat surface, but the same effect can be obtained even if it swells outward or inward.

An example in which a plurality of curvature sound insulation plates 30 are provided on one surface is shown in FIGS. As shown in the figure, even if a plurality of curvature sound insulation plates 30 are formed, the same sound insulation and vibration noise reduction effects can be exhibited. Furthermore, even if a plurality of curvature sound insulation plates 30 are mounted on all surfaces other than the surfaces to which the ducts 20 and 21 are connected, the same effect is exhibited (not shown). In FIGS. 13 and 14, the curvature sound insulation plate 30 is formed in close contact, but the same effect can be obtained even if the curvature sound insulation plate 30 is disposed apart.

Moreover, the example which changed the curvature in the curved surface part of the curvature sound insulation board 30 of the coupling | bond part 32 vicinity is shown in FIG. The curvature of the sound insulation board 30 is further increased by setting the curvature sound insulation board 30 near the coupling part 32 (part B) to a curvature Rb smaller than the curvature Ra from the curvature Ra near the apex (part A) of the curvature sound insulation board 30. Since the transmission of vibration sound due to surface vibration and radiation sound inside the housing is attenuated, the effect of noise attenuation in all bands is enhanced. In this example, the curvature Rb on the coupling portion 32 side is reduced by dividing it into two parts A and B. However, the curved surface is divided into two or more n parts, and the curvature Rn becomes smaller as it approaches the coupling portion 32 side. But it has the same effect.

Moreover, the example which changed the thickness in the curved surface part of the curvature sound insulation board 30 of the coupling | bond part 32 vicinity is shown in FIG. By setting the thickness of the curvature sound insulating plate 30 near the coupling portion 32 (B portion) to Tb thicker than Ta from the thickness Ta near the apex portion (A portion) of the curvature sound insulating plate 30, the curvature at the coupling portion 32 is obtained. The coupling strength between the sound insulating plate 30 and the plate material is increased, and the rigidity of the curvature sound insulating plate 30 is further increased. Since the vibration sound due to the vibration of the surface and the transmission of the radiated sound inside the housing are attenuated, the effect of the noise attenuation in the entire band increases. In this example, the thickness Tb on the coupling part 32 side is divided into two parts A and B, but the curved surface is divided into two or more parts and the thickness Tn approaches the coupling part 32 side. Even if the thickness is increased, the same effect can be obtained.

  The shape of the curvature sound insulation plate 30 has been described with respect to the semi-cylindrical and dome shape curvature sound insulation plate 30, but the hemispherical curvature sound insulation plate 30 has the same effect (not shown).

Embodiment 4 FIG.
As shown in FIG. 17, home appliances other than a duct ventilation fan, for example, the same effect can be exhibited even if it is mounted on the front surface side that can be a sound radiation surface to a consumer like the front surface of a washing machine. In FIG. 17, 60 is a main body exterior of the washing machine, 61 is a water tank, 62 is a dewatering tank, and 63 is a front face of the washing machine (sound radiating surface for consumers). As shown in the figure, most of the places where the washing machine is installed are often surrounded on both sides by walls, other structures, and home appliances. There are many cases. As a countermeasure against this sound radiation surface, it is possible to easily reduce sound radiation by attaching or fixing the noise reduction device 10 to the front panel 63.

  Since the noise reduction device according to the present invention is configured as described above, the following effects can be obtained. Since the noise reduction device is configured by a noise shielding plate having an arbitrary curvature radius provided entirely or partially, the configuration (device) is very simple and the weight of the device can be reduced. As a result, integration into home appliances becomes easy, and it becomes possible to provide excellent home appliances with low noise at low cost.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Moreover, in the said embodiment, although the example which applies this invention to an air blower (duct ventilation fan) or a washing machine was shown, it is not limited to the said product, For example, all such as a dehumidifier and an air conditioner generate | occur | produce sound. Applicable to equipment.

  Although the curvature sound insulation board 30 in the present invention is constituted by a curvature portion, even if a plane portion is partially formed within a range not departing from the curvature portion, substantially the same effect is obtained.

  As an application example of the present invention, there is a noise reduction device capable of attenuating all frequency ranges of noise in a wide frequency range (various frequency characteristics) of a duct ventilation fan.

BRIEF DESCRIPTION OF THE DRAWINGS It is an apparatus mounting schematic diagram which shows the duct ventilation fan to which the noise reduction apparatus which concerns on Embodiment 1 of this invention is applied. It is an inner surface explanatory view of the noise reduction device according to Embodiment 1 of the present invention. It is sectional drawing which shows the structure method of the other curvature sound insulation board of this invention. It is sectional drawing which shows the design of the curvature sound insulation board of this invention. It is a frequency characteristic comparison figure of the noise of the duct ventilation fan of this invention. It is the front view and sectional drawing which show the structure method strengthened using the reinforcing material of the other curvature sound insulation board of this invention. It is sectional drawing which shows the structure method of the other curvature sound insulation board of this invention. It is sectional drawing which shows the structure method of the other curvature sound insulation board of this invention. It is the schematic which formed the noise reduction apparatus in 4 surfaces of the housing | casing of the duct ventilation fan of this invention. It is the top view which shape | molded the surface of the noise reduction apparatus of this invention in the dome shape. FIG. 10A is a cross-sectional view of FIG. 10A-A ′ in which the surface of the noise reduction device of the present invention is molded into a dome shape. FIG. 10B is a cross-sectional view of FIG. 10B-B ′ in which the surface of the noise reduction device of the present invention is molded into a dome shape. It is an external view which shows the Example of the other curvature sound insulation board of this invention. It is an external view which shows the Example of the other curvature sound insulation board of this invention. It is sectional drawing which shows the Example of the other curvature sound insulation board of this invention. It is sectional drawing which shows the Example of the other curvature sound insulation board of this invention. It is side part sectional drawing of the washing machine to which the noise reduction apparatus of this invention is applied.

Explanation of symbols

  2 duct ventilation fan, 10 noise reduction device, 20 air intake duct, 21 exhaust duct, 30 curvature sound insulation plate, 31 curvature surface portion, 32 joint portion, 33 bonding material, 35 rib (solid side), 36 concave portion reinforcing member, 37 convex shape Part reinforcement member, 50 dome shape curvature sound insulation board.

Claims (10)

A noise source using a rotating body such as a motor, a casing made of one or a plurality of plates that fix the noise source and cover the noise source, and the casing is joined by the plate material and substantially sealed A noise reduction device comprising: a noise shielding plate provided with a structured structure and having an arbitrary curvature radius provided in whole or in part on at least one surface of the plate member. The noise reduction device according to claim 1, wherein a coupling portion between the plate material and the noise shielding plate is provided on at least one surface of the plate material. The noise reduction device according to claim 1, wherein the joint portion is auxiliary joined such as adhesion or welding. The noise reduction device according to any one of claims 1 to 3, wherein the noise shielding plate is molded by at least one of metal or resin. The noise reduction device according to any one of claims 1 to 4, wherein one or a plurality of ribs are fixed to the concave side of the noise shielding plate. 6. The reinforcing member made of at least one material such as metal or resin having substantially the same shape as the curvature surface is provided on at least one of the concave side and the convex side of the noise shielding plate. The noise reduction apparatus in any one. The noise reduction device according to any one of claims 1 to 6, wherein the noise shielding plate is molded into a semi-cylindrical shape, a dome shape, or a hemispherical shape. The noise reduction device according to any one of claims 1 to 7, wherein the noise shielding plate has a curvature in the vicinity of the joint portion with the plate material smaller than a curvature in the vicinity of the apex of the noise shielding plate. The noise reduction device according to any one of claims 1 to 8, wherein the noise shielding plate has a plate thickness in the vicinity of the joint portion with the plate material that is thicker than that near the apex of the noise shielding plate. A fan, a motor for rotating the fan, a casing made of one or a plurality of plates that fix the motor and cover the motor, and a structure in which the casing is joined by the plate material and substantially sealed And a noise shielding plate in which an arbitrary curvature radius is provided in whole or in part in the casing is provided so as to bulge outward or inward.

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