JP2004028028A - Silencer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the noise of a wide frequency band from a low frequency band to a high frequency band, to reduce the pressure loss, and to prevent the generation of self-noise. <P>SOLUTION: This silencer comprises a bent ventilation passage composed of a very high density glass wool plate, and the glass wool as a sound absorbing material mounted oppositely to the ventilation passage. This silencer is used for reducing the noise propagated in the ventilation passage, the ventilation passage has a part of which a sectional area is kept constant in a state that its sectional shape is continuously changed from a rectangle A to a rectangle C through a square B, and a major axis of the rectangle A and a major axis of the rectangle C are positioned to be intersected with each other. Further a center C11 of the major axis of the rectangle A and a center C13 of the major axis of the rectangle C are positioned in a state that halves of the rectangle A and the rectangle C are positioned out of a standard axis Ba1 within a range overlapped to the square B, when a straight line extended in the axial direction of the ventilation passage through a symmetrical center of the square B is the standard axis Ba1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a silencer, and more particularly to a passive silencer that is effective against low-frequency band noise, such as that generated by a blower, that propagates through, for example, air supply and exhaust ducts for air conditioning.
[0002]
[Prior art]
As a silencer for silencing noise propagating in a ventilation path such as an air conditioning duct, for example, a silencer described in Japanese Patent Application Laid-Open No. 57-119120 is known. This silencer is provided with a spiral partition plate in the gap between the inner cylinder and the outer cylinder, and a part of the fluid flows inside the inner cylinder and the remainder flows while turning in the circumferential direction through the gap. It is. This silencer sets the path length by the gap in accordance with the frequency of the sound to be silenced, and attempts to silence the sound to be silenced by causing the sound waves to be silenced to interfere with each other at the junction of the gap and the inner cylinder. Is what you do.
[0003]
As a muffler, for example, a muffler capable of opening and closing an X-type shielding plate described in Japanese Patent Application Laid-Open No. 61-38113 is known. This silencer is composed of two or more shields and sound absorbing plates, which alternately cross each other almost at the center, are combined in an X shape at a free angle, and can be opened and closed with one of the shields and sound absorbing plates or the center as a fulcrum. is there. This silencer is capable of freely opening and closing the X type and changing the angle, and attempts to mute the sound to be silenced by adjusting the frequency and the volume reduction.
[0004]
As a muffler, for example, a muffler described in JP-A-63-23367 is known. This silence muffler has a horizontally elongated, substantially box-shaped muffler main body, an exhaust inlet and an exhaust outlet provided concentrically at the lower and upper central portions of the muffler main body, respectively, and the inside of the muffler main body has a horizontal blind plate. A horizontal blind plate for dividing the exhaust gas into the lower chamber from the exhaust inlet, a baffle plate for diverting the exhaust gas introduced into the lower chamber in the horizontal direction, and a punching plate and a resonance tube appropriately arranged in the chamber. This silence muffler is intended to muffle the sound to be silenced by rapidly expanding the exhaust gas from the exhaust pipe to the chamber, silencing the inside of the chamber, and merging and collapsing the exhaust gas from the substantially opposite direction at the time of ejection.
[0005]
The silencer described in Japanese Patent Application Laid-Open No. 57-119120 is excellent in silencing a sound to be silenced, but has a structure in which the path length of the gap is set according to the frequency of the sound to be silenced. This has the disadvantage that the frequency band of the sound to be silenced is easily limited to a predetermined range.
[0006]
The silencer described in Japanese Patent Application Laid-Open No. 61-38113 can appropriately set the sound to be silenced by adjusting the angle of the shielding and sound absorbing plate, but has a structure in which deterioration or failure of the rotating part may occur. Has the disadvantage of requiring maintenance. Further, this silencer has a drawback that a gap is formed between the shield and the sound absorbing plate and the main body depending on how the shield and the sound absorbing plate are adjusted, and a self-noise is generated by an air current passing through the gap.
[0007]
The noise reduction muffler described in Japanese Patent Application Laid-Open No. 63-23367 is excellent in reducing noise in a wider frequency band due to exhaust expansion, collision, and noise reduction during passage. Since the flow of exhaust gas is blocked, a pressure loss is likely to occur, and there is room for improvement in suppressing the pressure loss. Further, this silencer muffler has a structure in which a ventilation path is formed in a direction orthogonal to the flow direction of the exhaust gas up to that time, and has a disadvantage that the installation location is easily limited.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and can muffle sound in a wide frequency band from a low frequency band to a high frequency band, reduce pressure loss, and suppress occurrence of self-noise. It is an object to provide a simple silencer.
[0009]
[Means for Solving the Problems]
The present invention utilizes the absorption of sound by a sound absorbing material and the reflection and interference of sound in an air passage having a cross-sectional shape in which the cross-sectional area is constant and the direction and position are continuously changed. This is to muffle sound in a wide frequency band up to low pressure loss.
[0010]
That is, the muffler of the present invention has a bent air passage, a sound absorbing material provided facing the air passage, is a muffler for muffling noise transmitted through the air passage, the air passage, It is a portion where the cross-sectional area is continuous and constant, and the cross-sectional shape is an elongated shape from the first shape which is an elongated shape, through the second shape which is a point-symmetric or line-symmetric shape. Including a portion that continuously changes to the third shape, the long axis of the first shape and the long axis of the third shape are in a positional relationship intersecting with each other, and the ventilation path passing through the center of symmetry in the second shape. When a straight line extending in the axial direction is used as a reference axis, the center of the long axis of the first shape and the center of the long axis of the third shape are at least part of each of the first shape and the third shape. The positional relationship deviates from the reference axis in a range overlapping the second shape.
[0011]
According to the configuration, the ventilation area in the ventilation path is constant, and the ventilation direction in the ventilation path changes in a range of an angle smaller than a right angle with respect to the ventilation direction before the muffler is introduced. Can be reduced.
[0012]
Further, according to the above configuration, since the air passage has wall surfaces inclined at various angles, the sound is likely to collide, and the sound is easily reflected in various directions and easily interferes. In addition, since the sound absorbing material is provided facing such a ventilation path, the sound colliding with the wall surface is easily absorbed.
[0013]
Further, in the ventilation path, the cross-sectional area is constant, and the cross-sectional shape changes from an elongated first shape to an elongated third shape through a symmetric second shape, and the first and third shapes are changed. The fact that the cross-sectional shape changes toward the positional relationship where the longitudinal direction (the longer side of the slender shape) intersects means that the longitudinal direction of the first shape changes from the first shape to the third shape. Means that the cross-sectional shape of the ventilation path changes in the direction in which it shrinks and the widthwise direction expands. According to such a change in the cross-sectional shape of the ventilation path, the sound propagating through the ventilation path cross-sections according to the ventilation direction. It tends to decay when the shape expands. The air passage has two directions, a longitudinal direction of the first shape and a longitudinal direction of the third shape, as directions in which the cross-sectional shape expands in accordance with the ventilation direction. This is advantageous in attenuating. Therefore, according to the shape of the ventilation path as described above, it is possible to muffle sound in a wide frequency band.
[0014]
Further, according to the configuration, the cross-sectional area of the ventilation path is kept constant, and since there is no movable member that is appropriately adjusted at the time of silencing such as a shielding plate or a reflecting plate, generation of self-noise is suppressed. It is possible.
[0015]
The silencer of the present invention has a bent air passage and a sound absorbing material provided facing the air passage. The ventilation path is a continuous portion having a constant cross-sectional area, the cross-sectional shape of the elongated shape from the first shape, through a second shape is a point-symmetric or line-symmetric shape, the elongated shape Including a portion that continuously changes to a certain third shape. Here, "bend" means that the axis of the ventilation path is bent. Further, "constant cross-sectional area" means that all areas of a continuously changing cross-sectional shape are substantially constant. In the present invention, the cross-sectional areas do not have to exactly match. Further, the axis of the air passage means a line connecting the centers of the cross-sectional shapes of the air passage.
[0016]
Regarding the first to third shapes, in the present invention, the major axis of the first shape and the major axis of the third shape are in a positional relationship to intersect each other and pass through the center of symmetry in the second shape. When a straight line extending in the axial direction of the ventilation path is used as a reference axis, the center of the long axis of the first shape and the center of the long axis of the third shape are at least each of the first shape and the third shape. A part is in a positional relationship deviated from the reference axis within a range overlapping the second shape.
[0017]
Here, the “long axis” in the first shape and the third shape refers to a longer one of the lines passing through the central portion inside the elongated shape (for example, in the case of a banana shape, connecting bent ends, Is an arcuate line passing through the center of the Further, the “center of symmetry” in the second shape refers to the center of symmetry in point symmetry or the midpoint in the shape of the line-symmetric symmetry axis. The reference axis is a straight line passing through the center of the symmetry and extending in a direction orthogonal to a plane including the second shape.
[0018]
The first shape is an elongated shape, and may be symmetric or asymmetric. Preferred first shapes include, for example, elliptical, semicircular, rectangular and the like. The second shape is a point-symmetric or line-symmetric shape. Preferred examples of the second shape include a circle and a square. The third shape is an elongated shape, and may be symmetric or asymmetric. Further, the third shape may be the same shape as the first shape, or may be a different shape. Preferred third shapes include, for example, elliptical, semicircular, rectangular and the like.
[0019]
The muffler according to the present invention includes the above-described portions, but may include an appropriate member for forming such a portion in the ventilation path, for example, the first shape or the third shape. A member such as a joint provided adjacent to the shape may be provided.
[0020]
Regarding the positional relationship between the first to third shapes, in the present invention, the first shape and the second shape, and the second shape and the third shape only need to have a positional relationship at least partially overlapping. However, it is preferable that the first shape and the third shape have a positional relationship such that they do not overlap with each other, in order to increase the number of collisions of sound with the wall surface of the ventilation path.
[0021]
In addition, regarding the positional relationship between the first, second, and third shapes, in a continuous cross section that forms the ventilation path, any two may be in a positional relationship that does not overlap with each other. In the case where the section where the cross-sectional shape of the air passage continuously changes from the first shape to the third shape is defined as one unit, and the air passage has n units directly, the sound on the wall surface of the air passage is It is preferable to increase the number of collisions, and when all the cross-sectional shapes included in the n units are targeted, it is preferable that at least two cross-sectional shapes have a positional relationship such that they do not overlap with each other.
[0022]
As such a positional relationship, for example, the first shape of a certain unit and the first shape of another unit do not overlap, and the first shape of a certain unit and the second shape of another unit are different. Positional relationship that does not overlap, positional relationship where the first shape in one unit does not overlap with the third shape of another unit, positional relationship where the second shape in a unit does not overlap with the first shape of another unit A positional relationship in which the second shape in one unit does not overlap with the second shape in another unit, a positional relationship in which the second shape in one unit does not overlap with the third shape of another unit, Positional relationship where the third shape and the first shape of the other unit do not overlap, such that the third shape of a certain unit does not overlap with the second shape of the other unit Relationship, a third shape and the positional relationship which does not overlap the third shape and the other units in a unit, and the like.
[0023]
In the present invention, the long axis of the first shape and the long axis of the third shape are in a positional relationship orthogonal to each other, and the first shape and the third shape are based on the position of the second shape. It is preferable to form a ventilation path having a complicated cross-sectional shape and to attenuate the sound transmitted through the ventilation path.
[0024]
That is, a straight line including at least one point on the outer edge of the second shape is defined as one reference line, and a straight line orthogonal to the one reference line and including at least one point on the outer edge of the second shape is defined as the other. When the reference line, and extending along the longitudinal direction of the first shape and a straight line including at least one point on the outer edge of the first shape and one reference line is in a positional relationship that overlaps, It is preferable that a straight line extending along the longitudinal direction of the third shape and including at least one point on the outer edge of the third shape and the other reference line have a positional relationship of overlapping.
[0025]
Here, the “straight line including at least one point on the outer edge” indicates either a tangent line or a straight line including one side. That is, when the cross-sectional shape of the ventilation path is a polygon, a straight line including one side, or a straight line tangent to one corner can be shown, and when the cross-sectional shape of the ventilation path is non-square, such as a circle or an ellipse, a tangent is drawn. Show. When the cross-sectional shape of the ventilation path includes both a curved line and a straight line such as a semicircle, it can be arbitrarily selected from a straight line including one side, a straight line tangent to one corner, and a tangent line.
[0026]
In particular, in the present invention, the first shape is located at a position where the center of the long axis of the first shape is on the other reference line, and the third shape has one center of the long axis of the third shape. It is more preferable to be at a position on the reference line of. According to such a configuration, when the units are arranged in parallel, the cross sections forming the first shape are adjacent to each other at one end side of the unit, and the cross sections forming the third shape are formed at the other end side of the unit. The units are adjacent to each other, and one end face and the other end face of the unit are formed on a coaxial line.
[0027]
Particularly in the case of such a unit, if the first shape and the third shape are rectangular and the second shape is square, it is easy to manufacture, and a rectangular duct generally used for air conditioning and the like. It is preferable to apply to. Furthermore, it is preferable that the first shape and the third shape have a cross-sectional shape such that when the first shapes are adjacent to each other, the cross-sectional shape becomes a predetermined duct shape. Semicircular.
[0028]
When the two units in the parallel positional relationship are formed into one block, in the present invention, the fact that the two blocks are connected in series forms a complicatedly bent air passage, and a storage property during use. Is preferable, and is preferable for enhancing the noise reduction effect.
[0029]
As a connection form of the blocks, it is preferable that two of all cross-sectional shapes arranged in series in an air passage formed by the connection of the blocks have a positional relationship such that they do not overlap with each other. , Depending on the type of block. For example, when connecting blocks having the same structure, it is preferable to connect the blocks so that the first shape and the third shape match at the connection portion.
[0030]
In the present invention, from the viewpoint of forming a complicatedly bent ventilation path, it is particularly preferable to connect two blocks that are in a mirror image relationship with each other. When connecting such blocks, it is preferable to connect the blocks such that the long axis of the first shape and the long axis of the third shape are orthogonal to each other. Here, the “mirror image relationship” refers to a state in which the relationship between two objects is in a relationship between one object and the image reflected on a mirror.
[0031]
The silencer of the present invention can be made of a known material. In the present invention, the air passage may be formed of a plate-shaped member such as an iron plate or a resin-made plate-shaped member, or a resin-made integrally molded product. The material of the air passage is appropriately selected according to the use conditions of the muffler of the present invention and the like. In the present invention, it is preferable that the air passage is formed of an ultra-high-density glass wool plate in order to muffle sound in a low frequency band. Here, the “ultra-high-density glass wool plate” means that glass wool is pressed using an adhesive or the like, and the density of the glass is 200 kg / m. ³ Say something about. The ultra-high-density glass wool plate has a glass density about three times that of a commonly used glass duct.
[0032]
In the case where the ventilation path is formed of an ultra-high-density glass wool plate, the thickness of the ultra-high-density glass wool plate is preferably about 10 to 15 mm in order to muffle low-frequency band sounds. If the thickness of the ultra-high-density glass wool plate is too thin, sound may be transmitted too much to reduce the sound-muffling effect and the strength of the ventilation path may be insufficient. On the other hand, if the thickness of the ultra-high-density glass wool plate is too large, the ventilation path becomes heavy, which makes it difficult to install a muffler, which is not preferable.
[0033]
As the sound absorbing material used in the present invention, a known sound absorbing material made of a cotton-like fiber such as glass wool or rock wool can be used. In the present invention, it is preferable that the sound absorbing material is glass wool in order to muffle sound in a high frequency band. The sound absorbing material is appropriately selected according to the conditions of use of the muffler of the present invention and the like. For example, when the muffler of the present invention is used in an exhaust system of an internal combustion engine, it is preferable to use rock wool having higher heat resistance as a sound absorbing material. In the present invention, the thickness of the sound absorbing material supported on the ventilation side wall surface varies depending on the type of the sound absorbing material, the loudness of the sound to be silenced, and the like. For example, glass wool is preferably about 25 mm.
[0034]
The sound absorbing material can be supported by, for example, bonding to the ventilation side wall surface with an adhesive. In the present invention, it is preferable to use a pressing member that presses the sound absorbing material toward the ventilation side wall from the viewpoint of preventing the sound absorbing material from scattering when applied when the ventilation speed in the ventilation path is high. Examples of such a holding member include a glass cloth, a filament mat (a plate-like molded product of glass wool), and a punching plate.
[0035]
Further, in the present invention, an appropriate connection member may be used for connection between the units and the blocks and connection between the muffler and the ventilation system. As the connection member, a member having an appropriate configuration may be used according to the cross-sectional shape and the number thereof appearing on the end face of the unit or the block, such as a flange.
[0036]
Further, in the present invention, the number of air passages is not particularly limited. For example, as long as the increase in pressure loss and the occurrence of self-noise can be suppressed, more air passages may be arranged in either the serial or parallel direction. good.
[0037]
The silencer of the present invention has a small pressure loss, is unlikely to generate self-noise, has an excellent silencing effect, can be reduced in weight, and is excellent in versatility. It is possible to apply to. Therefore, the muffler of the present invention can be used, for example, in a duct system provided with a blower in an air-conditioning / ventilation facility, an engine exhaust pipe system (flue) of a generator, a machine tool, a construction vehicle, etc., and a supply / exhaust duct housed in a vertical shaft. It can be applied to various ventilation systems such as a parking lot, a supply / exhaust duct of a subway and the like.
[0038]
BEST MODE FOR CARRYING OUT THE INVENTION
As shown in FIG. 1, the silencer in the present embodiment has a block 1, a block 2 connected in series to the block 1, a flange 3, and a flange 4. Block 1 is composed of units 1A and 1B, and block 2 is composed of units 2A and 2B. A flange 3 is connected to one end of the block 1. One end of the block 2 is connected to the other end of the block 1. A flange 4 is connected to the other end of the block 2. The block 1 and the block 2 are mirror images of each other, that is, the two blocks are in the relationship between one block and the image reflected on the mirror, and have the same structure except for the mirror image. is there.
[0039]
In the block 1, as shown in FIGS. 2 and 3, rectangular openings of each unit are vertically arranged side by side at one end to form a square shape, and rectangular openings of each unit are horizontally arranged at the other end. A square shape is formed in parallel. The hatched portion shown in FIG. 2 is a portion that can be seen through the block 1 when viewed from the arrow X direction. The portion that can be seen through in block 1 is a reference line B11, which is a straight line that bisects the end surface of block 1 in the vertical direction, and a reference line B12, which is a line that is orthogonal to reference line Bl1 and bisects the end surface of block 1 in the lateral direction. When this is done, the block 1 is formed in the upper left and lower right regions with respect to the paper surface in FIG.
[0040]
As shown in FIG. 4 and FIG. 5, the block 2 has rectangular openings of each unit vertically arranged on one end side to form a square shape, and rectangular openings of each unit are horizontally arranged on the other end side. A square shape is formed in parallel. The hatched portion shown in FIG. 4 is a portion that can be seen through the block 2 when viewed from the arrow X direction. The portion seen through the block 2 is formed in the lower left and upper right regions of the end face of the block 2 divided into four by the reference line B11 and the reference line B12 with respect to the paper surface in FIG.
[0041]
The block 1 includes a unit 1A and a unit 1B arranged in parallel with the unit 1A. The unit 1B is obtained by rotating the unit 1A by 180 ° with the intersection of the reference line Bl1 and the reference line Bl2 as the center of symmetry, and has the same structure.
[0042]
Similarly, the block 2 includes a unit 2A and a unit 2B arranged in parallel with the unit 2A. The unit 2B is obtained by rotating the unit 2A by 180 ° with the intersection of the reference line B11 and the reference line B12 as the center of symmetry, and has the same structure.
[0043]
As shown in FIGS. 6 and 7, the unit 1 </ b> A, when viewed from the direction of the arrow X in FIG. The cross-sectional shape continuously changes to a horizontally long rectangle C which is the shape. The rectangle A, the square B, and the rectangle C have substantially the same area, the rectangle A and the rectangle C have the same size, and the ratio of the long side to the short side is about 2: 1.
[0044]
As shown in FIG. 6, when viewed from the direction of the arrow X in FIG. 1, the rectangle A has one long side overlapping the reference line B11, and the center C11 of the long axis of the rectangle A is positioned on the reference line B12. It is in a certain position. The square B is located at a position where one side overlaps the reference line Bl1 and another side adjacent to the one side overlaps the reference line Bl2. The rectangle C has one long side overlapping the reference line B12, and the center C13 of the long axis of the rectangle C is located on the reference line B11. The hatched portions in FIG. 6 indicate portions that can be seen through the unit 1A.
[0045]
As shown in FIG. 7, when a straight line passing through the center C12 of symmetry of the square B and perpendicular to the plane including the square B is set as the reference axis Ba1, as shown in FIG. The center C11 of the middle axis and the center C13 of the long axis of the rectangle C have a positional relationship deviated from the reference axis Ba1.
[0046]
That is, the unit 1A has a wall surface including the reference line Bl1 and a plane including the reference line Bl2 as a wall surface. When the wall surface including the reference line Bl1 is used as a reference, the unit 1A has a rectangular shape with respect to the paper surface in FIG. The height decreases while moving upward from A and expands leftward to reach square B, and expands and moves downward while moving rightward from square B with reference to the wall surface including reference line B12. An air passage having a cross-sectional shape extending to a rectangle C is formed by the wall surface of the air passage.
[0047]
Similarly, as shown in FIG. 8 and FIG. 9, the unit 2 </ b> A passes through the second shape, the square B, from the vertically long rectangle A, which is the first shape, when viewed from the arrow X direction in FIG. 1. The cross-sectional shape changes continuously into a horizontally long rectangle C which is a third shape. The rectangle A, the square B, and the rectangle C have substantially the same area, the rectangle A and the rectangle C have the same size, and the ratio of the long side to the short side is about 2: 1.
[0048]
As shown in FIG. 8, when viewed from the direction of arrow X in FIG. 1, rectangle A has one long side overlapping reference line B11 and center C21 of the long axis of rectangle A is positioned on reference line B12. It is in a certain position. The square B is located at a position where one side overlaps the reference line Bl1 and another side adjacent to the one side overlaps the reference line Bl2. The rectangle C has one long side overlapping the reference line B12, and the center C23 of the long axis of the rectangle C is located on the reference line B11. The hatched portions in FIG. 8 indicate portions that can be seen through the unit 2A.
[0049]
As shown in FIG. 9, when a straight line passing through the center C22 of symmetry of the square B and perpendicular to the plane including the square B is set as the reference axis Ba2, as viewed in the direction of the arrow Y in FIG. The center C21 of the middle axis and the center C23 of the long axis of the rectangle C are in a positional relationship deviated from the reference axis Ba2.
[0050]
That is, the unit 2A has a wall surface including the reference line Bl1 and a plane including the reference line Bl2 as a wall surface. When the wall surface including the reference line Bl1 is used as a reference, the unit 2A has a rectangular shape with respect to the paper surface in FIG. A is reduced while moving downward from A and expanded leftward to a square B, and is expanded and reduced upward from the square B and reduced upward to form a rectangle C based on the wall surface including the reference line B12. Is formed by the wall surface of the ventilation path.
[0051]
The unit 1A is constituted by the segments shown in FIGS. This segment is composed of an ultra-high-density glass wool plate formed in the shape of each of the ad surfaces and a glass wool as a sound absorbing material adhered to the ultra-high-density glass wool plate. The rectangle formed on one end surface of the segment is a rectangle A or a rectangle C (FIG. 10), and the square formed on the other end surface of the segment is a square B (FIG. 11). The unit 1A is configured by connecting two segments such that the b-plane and the d-plane and the a-plane and the c-plane of these segments are adjacent to each other.
[0052]
Similarly, the unit 2A is constituted by the segments shown in FIGS. This segment is composed of an ultra-high-density glass wool plate formed in the shape of each of the ad surfaces and a glass wool as a sound absorbing material adhered to the ultra-high-density glass wool plate. The rectangle formed on one end face of the segment is a rectangle A or a rectangle C (FIG. 14), and the square formed on the other end face of the segment is a square B (FIG. 15). The unit 2A is configured by connecting two segments such that the b-plane and the d-plane and the a-plane and the c-plane of these segments are adjacent to each other.
[0053]
As shown in FIG. 18, each surface of the segments is joined by fixing an ultra-high-density glass wool plate with a staple 5 and applying an aluminum foil tape 6 along a joining edge. The glass wool as a sound absorbing material to be internally bonded is entirely adhered to an ultra-high-density glass wool plate by, for example, an adhesive.
[0054]
Further, as shown in FIGS. 19 and 20, each segment and each block are bonded to each other with an ultra-high-density glass wool plate without a gap by using, for example, a vinyl acetate adhesive, and an aluminum foil is formed along the bonding edge. They are connected by applying a tape 6.
[0055]
Further, as shown in FIG. 21, the block and the flange are connected via a connection duct 7 made of an ultra-high-density glass wool plate. The connection duct 7 is formed by joining ultra-high-density glass wool plates in the same manner as each surface of the segment, and the block and the connection duct are made of an adhesive and an aluminum foil as in the connection of each segment and each block. The connection duct 7 and the flange 4 are connected by a tape and a bolt and a nut.
[0056]
In the silencer according to the present embodiment, block 1 and block 2 are connected such that reference line Bl1 and reference line Bl2 overlap when viewed in the direction of arrow X in FIG. More specifically, the air passage formed by the unit 1A is divided into an air passage formed by the unit 2A and an air passage formed by the unit 2B, and the air passage formed by the unit 1B is also formed by the unit 2A. It is connected so as to be divided into an air passage and an air passage formed by the unit 2B. As a result, in each unit, an air passage having a portion that appears to penetrate is formed as shown by the hatched portion, but the silencer according to the present embodiment has, when viewed from the arrow X direction, An air passage having a positional relationship in which the squares B do not overlap each other is formed between the units.
[0057]
Since the silencer according to the present embodiment has the above-described configuration, it can exhibit an excellent silencing effect and reduce pressure loss. First, the results of evaluating the pressure loss between the silencer in the present embodiment and a known silence elbow are shown below.
[0058]
The silencer according to the present embodiment has a glass density of 200 kg / m. ³ Using an ultra-high-density glass wool plate with a thickness of 12 mm and a glass density of 32 kg / m ³ Glass wool was used. The sound absorbing material was 25 mm in thickness and was internally stuck on an ultra high density glass wool plate. On the other hand, an outer angle elbow having a duct diameter of 400 mm was used as a silencing elbow for comparison. The diameter of the silencer in the present embodiment was adjusted to the diameter of the silence elbow.
[0059]
The pressure loss is obtained by connecting the muffler to a duct, changing the wind speed in the duct, and measuring the pressure difference before and after the muffler. The same applies to the silence elbow. The results are shown in FIG. The pressure loss of the silencer in the present embodiment is equivalent to one silence elbow.
[0060]
This is because even if the cross-sectional area of the air passage of the silencer in the present embodiment is constant and the air passage is bent in a complicated manner, the wall surface of the air passage is parallel to the direction of arrow X in FIG. This is considered to be because the air flow introduced into the air passage is not changed suddenly or more than a right angle, and the air flow is hardly subjected to resistance in the air passage.
[0061]
The results of evaluating the silencing effect of the silencer in the present embodiment and a known silencing elbow are shown below. In this evaluation, the above-described silencer of the present embodiment, the silencer A, the silencer B, and the silence elbow were used. The silencer A has the same configuration as the silencer of the present embodiment except that an iron plate is used instead of the ultra-high density glass wool plate. The silencer B is configured in the same manner as the silencer of the present embodiment except that it has no sound absorbing material, that is, is composed of only an ultra-high density glass wool plate. The above-mentioned silencing elbow was used as a known silencing elbow.
[0062]
The muffling effect is obtained by connecting the muffler or the like to be measured to a duct, measuring the loudness of each predetermined frequency band on each of the upstream side and the downstream side of the muffler, and calculating the difference between these. And the amount of attenuation by a silencer or the like. The results are shown in FIG. The silencer according to the present embodiment has a better silencing effect than a single silencing elbow in all measured frequency bands.
[0063]
More specifically, in the silencer according to the present embodiment, in the bass range below 500 Hz, a silencing effect equivalent to that obtained by connecting two silencing elbows in series is achieved. In a sound range of 500 Hz or more and less than 2 kHz, the same silencing effect as that obtained by connecting two silencing elbows in series is achieved. In a high frequency range of 2 kHz or more, the same silencing effect as that obtained by connecting four silencing elbows in series is achieved.
[0064]
Note that the silencers A and B also have excellent silencing effects equivalent to two to four silence elbows depending on the frequency band, as compared to known silence elbows.
[0065]
The reason that the silencer in the present embodiment exhibits the above-described excellent silencing effect is due to the configuration material of the ventilation path and the shape of the ventilation path such as the cross-sectional shape and the cross-sectional arrangement of the ventilation path. it is conceivable that.
[0066]
As a mechanism of silencing by the constituent material of the air passage, the following mechanism is exemplified. That is, the sound colliding with the wall surface of the ventilation path is first absorbed by the sound absorbing material. Sound that is not absorbed by the sound absorbing material is reflected into the ventilation path by the ultra-high-density glass wool plate, interferes with the sound propagating through the ventilation path, and cancels out. Furthermore, sound that is not reflected by the ultra-high density glass wool plate passes through the ultra-high density glass wool plate and is attenuated during this time.
[0067]
In the silencer according to the present embodiment, it is considered that noise is silenced by the silencing mechanism described above. However, it is considered that the shape of the ventilation path synergistically enhances each of the silencing effects of the constituent materials. Can be That is, in the silencer according to the present embodiment, when viewed from the direction of arrow X, since the ventilation paths in which the squares B do not overlap each other are formed, the sound propagating through the ventilation paths is not It is easy to hit the road wall.
[0068]
In the silencer according to the present embodiment, in the cross-sectional shape of the ventilation path, the center of rectangle A and the center of rectangle C are located at positions deviated from a reference line passing through the center of square B, and the axis of the ventilation path is used as a reference. Then, the wall surfaces of the air passages opposed to each other with the axis interposed therebetween have an asymmetric positional relationship with each other. Since the sound propagating through the air passage collides with the wall surface of the air passage forming the biased cross-sectional shape as described above, it is considered that the sound is reflected in various directions, and the attenuation effect due to interference is further enhanced.
[0069]
Further, in the silencer according to the present embodiment, the cross-sectional area does not change, but the cross-sectional shape changes slenderly along Bl1 or Bl2, and the sound propagating through the ventilation path is easily attenuated along the slender changing direction. . Since the direction in which the sound is easily attenuated, that is, the longitudinal direction of the rectangle A and the longitudinal direction of the rectangle C are two in one unit, the muffler according to the present embodiment propagates through the ventilation path. This is considered to be more effective for sound attenuation due to sound.
[0070]
Further, in the silencer according to the present embodiment, since one ventilation path is divided into two ventilation paths, and a ventilation path merging with one ventilation path is formed, two ventilation paths are provided in one block. Is formed, and a ventilation path that branches and merges into two is formed, so that it is more effective to attenuate the sound at the merging point due to collision of sound.
[0071]
In addition, the silencer in the present embodiment can be installed in place of a straight-body duct since both end faces are on the same axis and the end faces are in a positional relationship overlapping when viewed from the arrow X direction. . Further, the width of the muffler along the direction of the arrow Y is about 1.4 times as large as the width at the end, and the occupied space per muffling effect is smaller than that of a known muffling elbow.
[0072]
Further, the silencer in the present embodiment has the same weight as one silence elbow, and can reduce the weight per silence effect obtained as compared with a silence elbow of the same diameter. It can be applied to places where weight restrictions are imposed at the time of installation, such as when hanging.
[0073]
Further, the silencer according to the present embodiment has a constant cross-sectional area of the ventilation path and a small pressure loss as described above, so that it is not necessary to increase the blowing power in order to secure a blowing amount associated with the installation of the muffler. In addition, it is possible to reduce the blowing power of the blower, which is a noise generation source, per installed muffler.
[0074]
Further, in the silencer according to the present embodiment, since a ventilation path that is complicatedly bent by the wall of the ventilation path is formed, a movable member such as a shielding plate is not required to obtain the above-described excellent noise reduction effect. Excellent maintenance-free silencing effect in the frequency band.
[0075]
In the present embodiment, an example suitable for application to a square air-conditioning duct has been described as an example, but the muffler of the present invention is not limited to such an embodiment, and for example, as shown in FIG. Includes those that form an air passage that changes continuously in cross-sectional shape. This air passage is formed by dividing a circle into two halves, and is formed by dividing a circle into two parts, from a semicircle A, which is a first shape, to a semicircle A, which is a first shape, through a circle B, which is a second shape. This is an air passage that is formed in a semicircular shape and changes continuously to a semicircle C that is a third shape.
[0076]
In this ventilation path, the straight line that is the diameter of the semicircle A overlaps the reference line B11, the straight line that is the diameter of the semicircle C overlaps B12, and the circle B is in contact with the reference line B11 and in contact with the reference line B12. is there. The center C11 of the long axis of the semicircle A is on the reference line B12, and the center C13 of the long axis of the semicircle C is on the reference line B11. For example, by connecting units having such a cross-sectional shape in the same manner as in the present embodiment, a muffler suitably applied to a circular duct generally used for an exhaust pipe or the like is configured.
[0077]
Further, in the present embodiment, the first shape and the third shape in the present invention have been described as an example in which the cross-sectional shape of the duct to which the silencer is to be connected is divided into two. The silencer of the present invention is not limited to such an embodiment, and includes, for example, a silencer that forms an air passage that continuously changes in cross-sectional shape as shown in FIG. This ventilation path is a ventilation path that continuously changes from a vertically long elliptical shape A that is the first shape to a horizontally long elliptical shape C that is the third shape via a circle B that is the second shape. .
[0078]
In this ventilation path, the major axis of the ellipse A is parallel to the reference line B11 and the ellipse A is tangent to the reference line B11, the major axis of the ellipse C is parallel to the reference line B12 and the ellipse C is the reference The circle B is in contact with the line B12, and the circle B is in contact with the reference line B11 and in contact with the reference line B12. The center C11 of the major axis of the ellipse A is on the reference line B12, and the center C13 of the major axis of the ellipse C is on the reference line B11. For example, when a unit having such a cross-sectional shape is formed by molding or the like at the time of crimping glass wool and applied to an air-conditioning duct or the like, these shapes are separated from each other without a gap corresponding to the ellipse A and the ellipse C. By connecting these units using a connectable flange or connection duct, it is possible to construct a muffler that is expected to have a higher level of sound reflection and attenuation effect due to interference.
[0079]
Further, in the present embodiment, the first, second, and third shapes of the present invention have been described by way of example having an air passage having a cross-sectional shape partially overlapping, but the muffler of the present invention has such a structure. The present invention is not limited to the embodiment, and includes, for example, an air passage that continuously changes in cross-sectional shape as shown in FIG. This ventilation path changes from a vertically long rectangle A as a first shape to a horizontally long rectangle C as a third shape through a square B as a second shape. This is the same as the air passage in the silencer of the embodiment, but differs from the above-described embodiment in that the first and third shapes are in a positional relationship not overlapping each other.
[0080]
In such an air passage, since one unit includes cross-sectional shapes having a positional relationship that does not overlap each other, it is effective in causing sound to collide with a wall surface of the air passage. Such a form is preferable when a high noise reduction effect is required with a small number of units, such as one unit or two units connected in series, and is effective, for example, when applied to a small machine.
[0081]
【The invention's effect】
The muffler of the present invention is a muffler having a bent air passage and a sound absorbing material provided facing the air passage to muffle noise propagating through the air passage. It is a portion where the area is constant and continuous, and from the first shape whose cross-sectional shape is an elongated shape, through the second shape which is a point-symmetric or line-symmetric shape, the third shape which is an elongated shape A portion that continuously changes to the shape of the first shape, the major axis of the first shape and the major axis of the third shape are in a positional relationship intersecting each other, and the axis of the air passage passing through the center of symmetry in the second shape When a straight line extending in the direction is used as a reference axis, the center of the long axis of the first shape and the center of the long axis of the third shape are at least partly of the first shape and the third shape. Because the position is off the reference axis in the range where the two shapes overlap, from the low frequency band to the high frequency band Wide can mute the sound of a frequency band, the pressure loss is small, it is possible to prevent the occurrence of self-noise.
[0082]
Further, in the present invention, when the first shape and the third shape are in a positional relationship not overlapping each other, it is even more effective in muting sound in a wide frequency band from a low frequency band to a high frequency band. .
[0083]
Further, in the present invention, when a portion in which the cross-sectional shape of the air passage continuously changes from the first shape to the third shape is taken as one unit, the air passage has n units in series, and n When all the cross-sectional shapes included in the unit are targeted, if at least two cross-sectional shapes do not overlap each other, sound in a wide frequency band from a low frequency band to a high frequency band is muted. Is even more effective.
[0084]
In the present invention, a straight line including at least one point on the outer edge of the second shape is defined as one reference line, and a straight line orthogonal to the one reference line and including at least one point on the outer edge of the second shape is defined as a straight line. When the other reference line, and extending along the longitudinal direction of the first shape and a straight line that includes at least one point on the outer edge of the first shape and the one reference line is in a positional relationship that overlaps, If the straight line extending at least one point on the outer edge of the third shape and the other reference line extend along the longitudinal direction of the third shape and overlap with the other reference line, the pressure loss is small, and the occurrence of self-noise is reduced. It can be prevented and is more effective in silencing sounds in a wide frequency band.
[0085]
Further, in the present invention, the first shape is located at a position where the center of the long axis of the first shape is on the other reference line, and the third shape is such that the center of the long axis of the third shape is on the one reference line. The position on the line is more effective in reducing the pressure loss.
[0086]
Further, in the present invention, when a structure having two air passages and a structure in which the first shapes and the third elongated shapes are united so as to be in parallel is defined as one block, the two blocks are connected. When it is configured, it is even more effective in enhancing the noise reduction effect.
[0087]
Further, in the present invention, the two blocks are in a mirror image relationship with each other, and are connected so that the long axes of the respective blocks are orthogonal to each other at the connection portion. More effective.
[0088]
In the present invention, when the first shape and the third shape are rectangular and the second shape is square, it is even more effective in silencing sounds in a wide frequency band.
[0089]
Further, in the present invention, the ventilation path has at least two units in parallel, the cross sections forming the first shape in each unit are adjacent to each other, and form the third shape in each unit. When the cross-sections are adjacent to each other, two air passages that are divided and merged with the same path length are formed, which is even more effective in silencing sound in a wide frequency band.
[0090]
Further, according to the present invention, when two units having a parallel positional relationship are formed into one block, if the two blocks are connected in series, a complicatedly bent air passage is formed, and a sound in a wide frequency band is formed. Is more effective in canceling the sound, and the two blocks are in a mirror image relationship with each other, and are more effective when the second shapes are in a positional relationship where the second shapes do not overlap each other.
[0091]
In the present invention, the ventilation path is formed of an ultra-high-density glass wool plate, and when the sound absorbing material is glass wool supported on the ventilation side wall surface of the ventilation path, a wide frequency range from a low frequency band to a high frequency band is provided. The sound in the band can be silenced, the pressure loss is small, and the occurrence of self-noise can be prevented.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a muffler according to an embodiment of the present invention.
FIG. 2 is a diagram showing a state where the block 1 of the silencer shown in FIG. 1 is viewed from the direction of arrow X in FIG.
FIG. 3 is a diagram showing a state where the block 1 of the silencer shown in FIG. 1 is viewed from the direction of arrow Y in FIG. 1;
FIG. 4 is a diagram showing a state where the block 2 of the silencer shown in FIG. 1 is viewed from the direction of arrow X in FIG.
5 is a diagram showing a state where the block 2 of the silencer shown in FIG. 1 is viewed from the direction of arrow Y in FIG.
FIG. 6 is a diagram showing a positional relationship of a cross-sectional shape of the unit 1A shown in FIG. 1 when viewed from an arrow X direction in FIG.
7 is a diagram showing the unit 1A shown in FIG. 1 when viewed from the direction of arrow Y in FIG.
FIG. 8 is a diagram showing a positional relationship of a cross-sectional shape of the unit 2A shown in FIG. 1 when viewed from an arrow X direction in FIG.
9 is a diagram showing the unit 2A shown in FIG. 1 when viewed from the direction of arrow Y in FIG.
FIG. 10 is a front view of a segment constituting the unit 1A shown in FIG.
FIG. 11 is a rear view of a segment constituting the unit 1A shown in FIG. 1;
FIG. 12 is a plan view of a segment constituting the unit 1A shown in FIG. 1;
FIG. 13 is a side view of a segment constituting the unit 1A shown in FIG.
FIG. 14 is a front view of a segment constituting the unit 2A shown in FIG. 1;
FIG. 15 is a rear view of a segment constituting the unit 2A shown in FIG. 1;
FIG. 16 is a plan view of a segment constituting the unit 2A shown in FIG. 1;
FIG. 17 is a side view of a segment constituting the unit 2A shown in FIG.
FIG. 18 is an essential part enlarged cross-sectional view showing a joining portion of an ultra high density glass wool plate in each segment.
FIG. 19 is an enlarged cross-sectional view of a main part showing connection portions between segments and between blocks.
FIG. 20 is an enlarged sectional view of a main part showing a connection portion between each segment and between blocks.
FIG. 21 is an enlarged sectional view of a main part showing a connection part between a block and a flange.
FIG. 22 is a graph showing a relationship between a wind speed in a duct and a pressure loss in the silencer according to the present embodiment and a known silence elbow.
FIG. 23 is a graph showing a relationship between a frequency band and attenuation in the silencer according to the present embodiment and a known silence elbow.
24 is a diagram showing a positional relationship of a cross-sectional shape of another example of the unit 1A shown in FIG. 1 when viewed from the direction of arrow X in FIG. 1 in another example included in the present invention.
25 is a diagram showing a positional relationship of a cross-sectional shape of another example of the unit 1A shown in FIG. 1 when viewed from the direction of arrow X in FIG. 1 in another example included in the present invention.
26 is a diagram showing a positional relationship of a cross-sectional shape of another example of the unit 1A shown in FIG. 1 when viewed from the direction of arrow X in FIG. 1 in another example included in the present invention.
[Explanation of symbols]
One or two blocks
1A, 1B, 2A, 2B unit
3, 4 flange
5 Staples
6 Aluminum foil tape
7 Duct for connection
A First shape
B Second shape
C Third shape
Ba1, Ba2 Reference axis
Bl1, Bl2 Reference line
C11-C13, C21-C23 Long axis center

Claims (10)

A muffler for bending a ventilation path and a sound absorbing material provided facing the ventilation path, for muffling noise propagating through the ventilation path,
The ventilation path is a portion where the cross-sectional area is continuous and constant, and the cross-sectional shape is elongated from a first shape that is an elongated shape, through a second shape that is a point-symmetric or line-symmetric shape, and is elongated. Including a part that continuously changes to the third shape, which is a simple shape,
The long axis of the first shape and the long axis of the third shape are in a positional relationship intersecting each other,
When a straight line extending in the axial direction of the air passage passing through the center of symmetry in the second shape is used as a reference axis, the center of the long axis of the first shape and the center of the long axis of the third shape are: A silencer characterized in that at least a part of each of the first shape and the third shape has a positional relationship deviated from the reference axis within a range overlapping the second shape. The muffler according to claim 1, wherein the first shape and the third shape are in a positional relationship such that they do not overlap with each other. When a section in which the cross-sectional shape of the air passage changes continuously from the first shape to the third shape is taken as one unit, the air passage has n units in series, and n units The muffler according to claim 1, wherein at least two cross-sectional shapes are in a positional relationship such that they do not overlap each other when all the cross-sectional shapes included in are included. A straight line including at least one point on the outer edge of the second shape is defined as one reference line, and a straight line orthogonal to the one reference line and including a straight line including at least one point on the outer edge of the second shape is defined as the other. When the reference line,
A linear relationship extending along the longitudinal direction of the first shape and including at least one point on the outer edge of the first shape and the one reference line are in a positional relationship,
4. The positional relationship according to claim 3, wherein a straight line extending along a longitudinal direction of the third shape and including at least one point on an outer edge of the third shape overlaps the other reference line. The silencer described. The first shape is located at a position where the center of the long axis of the first shape is on the other reference line, and the third shape is such that the center of the long axis of the third shape is on the one reference line. The muffler according to claim 4, wherein the muffler is located at a position. The muffler according to any one of claims 1 to 5, wherein the first shape and the third shape are rectangular, and the second shape is square. The ventilation path has at least two units in parallel, and the cross-sections forming the first shape in each unit are adjacent to each other, and the cross-sections forming the third shape in each unit are adjacent to each other. The muffler according to claim 5, wherein the muffler has a positional relationship of: The muffler according to claim 7, wherein when the two units in a parallel positional relationship are formed into one block, the two blocks are connected in series. The muffler according to claim 8, wherein the two blocks have a mirror image relationship with each other, and the second shapes are in a positional relationship such that the second shapes do not overlap each other between the blocks. The air passage is formed of an ultra-high-density glass wool plate, and the sound absorbing material is glass wool supported on a ventilation side wall surface of the air passage. Silencer according to.

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