JP4864470B2 - Duct parts - Google Patents

Description

The present invention relates to superior duct products sound insulation effect.

A plurality of outer cylinders and inner cylinders provided coaxially with the outer cylinders on the inner side of the outer cylinders and penetrating through the inner circumferential surface of the inner cylinders to the inner side of the inner cylinders and the outer side of the inner cylinders 2. Description of the Related Art A duct component having a plurality of holes is known (see, for example, Patent Document 1).
A plurality of outer cylinders and inner cylinders provided coaxially with the outer cylinders on the inner side of the outer cylinders and penetrating through the inner circumferential surface of the inner cylinders to the inner side of the inner cylinders and the outer side of the inner cylinders There are known duct parts in which an inorganic silicate foam layer is formed in the space between the outer cylinder and the inner cylinder (see, for example, Patent Document 2).
An outer cylindrical body and an inner cylindrical body provided coaxially with the outer cylindrical body are provided inside the outer cylindrical body, and a spiral path extending from one end to the other end is formed between the outer cylindrical body and the inner cylindrical body. In addition, a duct component is known in which a silencing effect is obtained by waveform synthesis using the difference between the phase of sound passing through the inner cylinder and the phase of sound passing through the spiral path (for example, Patent Documents). (See 3 etc.).
Japanese Utility Model Publication No. 58-153934 JP-A-6-331208 JP-A-6-147624

  However, the duct parts disclosed in Patent Documents 1 to 3 are formed by an inner cylinder formed by a circular cylinder having a perfect cross section and a cylinder having a perfect circular section, and have an inner diameter that is larger than the outer diameter of the inner cylinder. A large outer cylinder is coaxially arranged, and an air layer is formed between the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder. Therefore, the area of the inner surface of the outer cylinder that is in contact with the air layer cannot be greater than the area of the inner surface of the outer cylinder that has a perfect circular cross section. Therefore, the area of the inner surface of the outer cylinder that is in contact with the air layer cannot be increased. It is not possible to effectively attenuate the low frequency component of.

The duct component according to the present invention includes an outer cylindrical body, an inner cylindrical body provided on the inner side of the outer cylindrical body, and an end portion of the outer cylindrical body and an inner cylindrical portion at the front and rear end portions of the outer cylindrical body and the inner cylindrical body. A closed body that connects the end portions of the body to each other and seals the end portion of the outer cylindrical body and the end portion of the inner cylindrical body in a sealed state, and the air surrounded by the outer cylindrical body, the inner cylindrical body, and the closed body The outer cylinder is formed such that the length of the left and right direction of the cylinder relative to the front and rear direction of the cylinder is longer than the length of the vertical direction of the cylinder, and the inner cylinder is formed at the front end of the cylinder The front perforated tube portion, the rear perforated tube portion formed at the rear end of the tube, and the non-hole formed in the center portion of the tube between the front perforated tube portion and the rear perforated tube portion A sound absorbing material portion provided on the outer peripheral side of the cylindrical portion and the rear perforated tube portion, wherein the sound absorbing material portion is cut off from the air layer, and the sound absorbing material is stored in the sound absorbing material storage portion. And the front perforated tube portion is inside the inner tube body And further comprising a plurality of comprising a hole, a plurality of holes penetrating across the interior of the inner and sound absorbing material housing portion of the rear side perforated tubular portion inner cylinder which penetrates across the air layer To do .

According to the present invention, since the length in the left-right direction of the cylinder of the outer cylinder is longer than the length in the vertical direction of the cylinder, the length in the left-right direction between the outer surface of the inner cylinder and the inner surface of the outer cylinder is increased. The length can be increased, the volume of the air layer can be increased, and the area of the inner surface of the outer cylindrical body in contact with the air layer can be increased. For this reason, the amount of attenuation due to collision of the low frequency component of sound with the air in the air layer increases, and further, the amount of attenuation due to collision of the low frequency component of sound with the inner surface of the outer cylinder increases. Therefore, the attenuation effect of the low frequency component of the sound is improved. That is, since the low frequency component of the sound can be effectively attenuated, a duct component having an excellent sound insulation effect can be obtained. In addition, since the inner cylindrical body includes the front perforated cylindrical portion, the rear perforated cylindrical portion, the non-perforated cylindrical portion, and the sound absorbing material portion, the inner cylindrical body passes through the hole of the front perforated cylindrical portion. The low frequency component of the sound that has entered the air layer from the inside is attenuated by the air layer, and the high frequency component of the sound that has entered the sound absorbing material portion from the inside of the inner cylinder through the hole in the rear perforated cylindrical portion is caused by the sound absorbing material. Absorbed and attenuated. Moreover, since the inner cylinder is provided with the non-hole cylinder, the pressure loss in the duct component can be reduced. That is, by reducing the number of holes formed in the inner cylinder, the pressure loss due to the holes can be reduced. Therefore, it is possible to obtain a duct component that can effectively attenuate both the low-frequency component and the high-frequency component of the sound and reduce the pressure loss .

Best form 1
1 to 3 show the best mode 1 of the duct part according to the present invention, FIG. 1 shows the duct part, FIG. 1 (a) shows the appearance of the duct part, and FIG. 1 (b) shows the duct part on the front side. Shown from. FIG. 2 shows a cross section of a duct part and a unit duct forming an exhaust duct. FIG. 3 shows an installation example of the exhaust duct. In this specification, the directions of “front”, “rear”, “left”, “right”, “upper”, “lower” are indicated by an arrow A with the duct part 1 placed in the state of FIG. This is the direction specified when viewed from the front side.

  The duct component 1 will be described with reference to FIG. The duct component 1 includes an inner cylindrical body 2, an outer cylindrical body 3, a closing body 4, and a connecting portion 5. The inner cylindrical body 2, the outer cylindrical body 3, the closing body 4, and the connecting portion 5 are formed of a metal plate having a thickness of about 0.5 mm to 1.6 mm.

  The inner cylinder 2 has a front end as one end in the direction along the center axis of the cylinder and a rear end as the other end in the direction along the center axis of the cylinder, that is, a circular cross section in which both front and rear ends of the cylinder are opened. It is formed by a cylindrical shape.

  The outer cylinder 3 is formed of a cylinder having a horizontally long cross-section that is flat in the left-right direction as a first orthogonal direction that is open at both front and rear ends of the cylinder and orthogonal to the direction along the center axis of the cylinder. That is, the outer cylinder 3 is formed by the upper and lower flat wall portions 6; 7 and the left and right side wall portions 8; 9. The upper and lower flat wall portions 6; 7 extend along the front-rear direction and the left-right direction of the cylinder, and the upper and lower flat walls 6; It is formed by flat plates facing each other in parallel in the direction. The left and right side wall portions 8; 9 are formed by long plates that are long before and after the semicircular arc shape of a cross-section of a circular cylinder with a perfect cross-section cut along the central axis of the cylinder. The left end portions of the upper and lower flat wall portions 6; 7 are connected to each other by the left side wall portion 8, and the right end portions of the upper and lower flat wall portions 6; 7 are connected to each other by the right side wall portion 9. A cylindrical body 3 is formed.

  The outer cylindrical body 3 is formed such that the length in the left-right direction of the cylinder (hereinafter referred to as the left-right length) W is longer than the length H in the vertical direction of the cylinder (hereinafter referred to as the vertical length) H. The left and right length W is the length between the left and right end outer surfaces of the outer cylinder 3, and the upper and lower length H is the length of the shortest portion between the upper and lower end outer surfaces of the outer cylinder 3. That is, the outer cylindrical body 3 is formed such that the length in the first orthogonal direction orthogonal to the central axis of the cylinder is longer than the length in the second orthogonal direction orthogonal to the central axis of the cylinder and the first orthogonal direction. The front and rear lengths of the outer cylindrical body 3 and the front and rear lengths of the inner cylindrical body 2 are the same. The inner cylinder 2 is provided inside the outer cylinder 3, the inner cylinder 2 and the outer cylinder 3 are arranged coaxially with each other, the front end of the outer cylinder 3, the front end of the inner cylinder 2, and the outer cylinder 3 and the rear end of the inner cylinder 2 are aligned with each other, the upper end of the outer peripheral surface of the cylinder of the inner cylinder 2 and the left and right on the inner surface of the flat wall portion 6 on the outer cylinder 3 The center is connected to each other from the front end to the rear end of the cylinder, and the lower end of the outer peripheral surface of the cylinder of the inner cylinder 2 and the center between the left and right of the inner surface of the flat wall portion 7 below the outer cylinder 3 are from the front end of the cylinder. Connected to each other across the rear end. The upper and lower connecting portions 10; 10 that connect the inner cylindrical body 2 and the outer cylindrical body 3 are formed at positions separated from each other by 180 degrees on the outer peripheral surface of the inner cylindrical body 2. Air layers 11; 11 delimited by the connecting portions 10; 10 are formed on the left and right sides of the inner cylinder 2 with the upper and lower connecting portions 10; That is, the outer cylindrical body 3 and the inner cylindrical body 2 are arranged coaxially, and the outer surface of the inner cylindrical body 2 and the inner surface of the outer cylindrical body 3 are connected to each other across the front and rear of the cylinder. Left and right directions between the outer surface of the inner cylindrical body 2 and the inner surface of the outer cylindrical body 3 by forming the air layers 11 separated by the connecting portions 10 on both the left and right sides of the cylinder of the inner cylindrical body 2 as a boundary. The length of the air layer 11 can be increased, the volume of the air layer 11 can be increased, and the area of the inner surface of the outer cylindrical body 3 in contact with the air layer 11 can be increased, so that the low frequency component of the sound collides with the air in the air layer 11. As a result, the amount of attenuation is increased, and the amount of attenuation due to collision of the low frequency component of the sound with the inner surface of the outer cylindrical body 3 is increased, so that the attenuation effect of the low frequency component of the sound is improved. Furthermore, it is provided with a flat wall portion 6; 7 formed by a pair of flat plates extending in the left-right direction of the cylinder and facing each other in parallel up and down, and has a flat shape in the left-right direction and a vertical length. Since the short outer cylinder 3 is provided, it is possible to obtain the duct component 1 that can be easily installed even in a ceiling space with a short vertical length. In addition, the above-mentioned connection is the state where the cylinder outer surface of the inner cylinder 2 and the cylinder inner surface of the outer cylinder 3 are in contact with each other but are not coupled, or the cylinder outer surface of the inner cylinder 2 and the outer cylinder 3 is a state in which the inner surface of the cylinder 3 is coupled to each other by an adhesive, engagement coupling, or the like.

  The lid 4 has a front lid 12 and a rear lid 13. The front lid 12 connects the front end of the inner cylindrical body 2 and the front end of the outer cylindrical body 3 to block the space between the front end of the outer cylindrical body 3 and the front end of the inner cylindrical body 2 in a sealed state. The rear lid 13 connects the rear end of the inner cylindrical body 2 and the rear end of the outer cylindrical body 3 to seal the space between the rear end of the outer cylindrical body 3 and the rear end of the inner cylindrical body 2 in a sealed state. An air layer 11 is formed by a space surrounded by the lid body 4, the outer cylinder body 3, and the inner cylinder body 2.

As shown in FIG. 2, the inner cylindrical body 2 includes a front perforated tube portion 15 at the front end of the tube, a rear perforated tube portion 16 at the rear end of the tube, A cylindrical portion between the rear perforated cylindrical portion 16 is formed in the non-perforated cylindrical portion 17. A sound absorbing material portion 20 is provided on the outer peripheral side of the rear perforated cylindrical portion 16 of the inner cylindrical body 2.
The front perforated cylindrical portion 15 and the rear perforated cylindrical portion 16 are configured such that a plurality of holes 18 penetrating the inner cylindrical body 2 and the air layer 11 are formed in the cylindrical wall of the inner cylindrical body 2. is there. For example, the front perforated cylinder part 15 and the rear perforated cylinder part 16 of the inner cylinder 2 are formed by a punching iron plate.
The sound absorbing material unit 20 includes a sound absorbing material storage unit 21 and a sound absorbing material 22 stored in the sound absorbing material storage unit 21. The sound absorbing material storage unit 21 is sealed by the inner cylinder 2, the outer cylinder 3, the left and right outer surrounding plates 23; 24, the left and right front closing plates 25; 26, and the rear lid 13. It is formed by a blocked space. The left and right outer surrounding plates 23; 24 are formed by long plates that are long in the front and rear of a cross-sectional arc shape that forms a part of a cylinder having a diameter larger than the diameter of the inner cylinder 2. The left and right outer surrounding plates 23 and 24 are arranged coaxially with the inner cylinder 2 on the left and right outer sides of the left and right semicircular arc-shaped cylindrical wall portions of the inner cylinder 2, and are arranged on the upper end and the outer cylinder 3. The flat wall portion 6 is connected to each other, and the lower end thereof and the flat wall portion 7 below the outer cylindrical body 3 are connected to each other. The left front closing plate 25 seals a space between the front end of the left outer surrounding plate 23, the outer peripheral surface of the inner cylindrical body 2, and the inner peripheral surface of the outer cylindrical body 3. The right front blocking plate 26 seals a space between the front end of the right outer plate 24, the outer peripheral surface of the inner cylindrical body 2, and the inner peripheral surface of the outer cylindrical body 3. The rear end of the left outer plate 23 and the front end of the right outer plate 24 and the rear lid 13 are connected to each other in a sealed state. A sound absorbing material 22 such as glass wool, glass fiber felt or non-woven fabric having open cells is stored in the sound absorbing material storage portion 21. The sound goes back and forth between the inside of the inner cylinder 2 and the inside of the air layer 11 via the front perforated cylinder 15 and the inside of the inner cylinder 2 and the sound absorbing material via the rear perforated cylinder 16. Go back and forth inside part 20.
The low-frequency component of the sound that has entered the air layer 11 through the plurality of holes 18 of the front perforated cylindrical portion 15 is attenuated by the air layer 11 and passes through the plurality of holes 18 of the rear perforated cylindrical portion 16. Thus, the high frequency component of the sound that has entered the sound absorbing member 20 is absorbed by the sound absorbing member 22 and attenuated. Moreover, since the inner cylinder 2 is provided with the non-hole cylinder part 17, the pressure loss in the duct component 1 can be made small. In other words, by reducing the number of holes 18 formed in the inner cylinder 2, pressure loss due to the holes 18 becoming resistance of air flowing through the cylinder of the inner cylinder 2, and air being in the cylinder of the inner cylinder 2 Since the pressure loss due to flowing out from the air layer 11 to the air layer 11 can be reduced and the pressure loss due to the holes can be reduced, the capacity as a blower can be reduced.

  The connecting part 5 includes a front connecting part 28 and a rear connecting part 29. The front side connecting part 28 and the rear side connecting part 29 are formed by a circular cylinder having a perfectly circular cross section in which both front and rear ends of the cylinder are open, and the diameter of the cylinder is the same as the diameter of the cylinder of the inner cylinder 2. . The front connecting portion 28 extends forward from the front end of the inner cylinder 2 by connecting the rear end of the cylinder and the front end of the cylinder of the inner cylinder 2 to each other. The rear connection portion 29 extends rearward from the rear end of the inner cylinder 2 by connecting the front end of the cylinder and the rear end of the inner cylinder 2 to each other.

As shown in FIG. 3, the duct component 1 is connected to an intermediate position of the exhaust duct 33 that connects the range hood 32 including the air-conditioning fan 31 and the outside of the apartment house 30 in the apartment house 30, whereby the exhaust duct 33. It can be made to function as a sound insulation duct for relay that forms a part of. That is, by providing the duct component 1 in a part of the exhaust duct 33, it is possible to form the exhaust duct 33 that can effectively attenuate both the low frequency component and the high frequency component of the sound. The exhaust duct 33 is formed by a plurality of unit duct parts 34 and the duct part 1. A unit duct part 34 as another duct part includes an inner cylinder 35 and an outer cylinder 36 that are coaxially arranged, and a heat insulating material 37 such as glass wool is provided between the inner cylinder 35 and the outer cylinder 36. It is the structure provided (refer FIG. 2). The inner cylinder body 35 and the outer cylinder body 36 are formed by a cylinder having a perfect circular cross section in which both front and rear ends of the cylinder are opened.
As the plurality of unit duct parts 34, a male unit duct part 41 having a connecting part similar to the connecting part 5 of the duct part 1 on both ends, and a female unit having a form having no connecting parts on both ends. A duct part 42 is used. When the exhaust duct 33 is configured by only a plurality of unit duct parts 34, the male unit duct part 41 is fitted by fitting the connecting portion of the male unit duct part 41 inside the inner cylinder 35 of the female unit duct part 42. And the female unit duct part 42 may be connected alternately, but in the best mode 1, the duct part 1 is connected instead of the single male unit duct part 41 positioned in the middle of the exhaust duct 33. To do. At this time, since the duct part 1 includes the connecting portion 5, the connection work with the female unit duct part 42 is facilitated, and the exhaust duct 33 can be easily disposed (see FIG. 2). That is, the duct part 1 is formed so that the outer diameter of the connecting part 5 fits the inner surface of the inner cylinder 35 of the female unit duct part 42, and the connecting part 5 is the end of the cylinder in the female unit duct part 42. Since it is formed so that it can be connected adjacent to the female unit duct part 42 by fitting into the inner surface of the inner cylindrical body 35 of the female unit duct part 42 from the side of the section, the pair with the female unit duct part 42 It is easy to attach, and the unity with the female unit duct part 42 can be improved.
Further, the duct component 1 is connected, for example, with the front end side positioned on the range hood 32 side and the rear end side positioned on the outside side of the apartment house 30.
In FIG. 3, 43 is a range stand, 44 is wall concrete, 45 is floor concrete, 46 is a floor, 47 is a ceiling, and 48 is a hanger for the exhaust duct 33.

The duct part 1 has, for example, a length of 500 mm before and after the outer cylinder 3 and the inner cylinder 2, a length of 60 mm before and after the connecting portion 5, a total length of 620 mm before and after the inner cylinder 2 and the connection The outer diameter of the portion 5 is 150 mm, the length between the inner surfaces of the upper and lower flat wall portions 6: 7 of the outer cylinder 3 (shortest distance dimension) is 150 mm, the left and right length W of the outer cylinder 3 is 360 mm or 500 mm, The front and rear lengths of the front perforated cylindrical portion 15 are 100 mm, the front and rear lengths of the sound absorbing material portion 20 and the rear perforated cylindrical portion 16 are 200 mm, and the length between the left end portion and the right end portion of the sound absorbing material portion 20 is The front and rear lengths of the non-perforated cylindrical portion 17 are 200 mm. The front perforated cylindrical portion 15 and the rear perforated cylindrical portion 16 are formed of, for example, a punching iron plate, and the aperture ratio of the plurality of holes 18 is 58%.
The male unit duct component 41 has, for example, a length of 1000 mm before and after the outer cylinder 36 and the inner cylinder 35, a length of 60 mm before and after the connecting portion, an outer diameter of the outer cylinder 36 of 250 mm, and an inner cylinder. The outer diameter of the body 35 and the connecting portion is 150 mm.
The female unit duct part 42 has, for example, a length of the outer cylinder 36 and the inner cylinder 35 of 1000 mm, an outer diameter of the outer cylinder 36 of 250 mm, and an inner diameter of both ends of the inner cylinder 35 of the duct part 1. The diameter of the connecting part 5 and the diameter of the connecting part of the male unit duct part 41 are larger by the plate thickness of the connecting part 5 of the duct part 1 and the connecting part of the male unit duct part 41.

  The operation of the duct component 1 will be described. When sound from the outside enters the exhaust duct 33, or when sound generated by driving the air conditioning fan 31 enters the exhaust duct 33 from the range hood 32 side, the sound functions as a duct part that functions as a relay sound insulation duct. 1 enters the air layer 11 via the hole 18 of the front perforated cylindrical portion 15, and enters the sound absorbing material storage portion 21 via the hole 18 of the rear perforated cylindrical portion 16. The low frequency component of the sound that has entered the air layer 11 collides with the air and the inner surface of the outer cylinder 3 and the outer surface of the inner cylinder 2 and is attenuated. In the best mode 1, the length in the left-right direction between the outer surface of the inner cylindrical body 2 and the inner surface of the outer cylindrical body 3 can be increased by increasing the left and right length W of the outer cylindrical body 3. Since the volume of the layer 11 can be increased, the attenuation amount of the low frequency component of the sound due to the collision between the low frequency component of the sound and the air can be increased, and further, the area of the inner surface of the outer cylinder 3 in contact with the air layer 11 can be increased. As a result, the low-frequency component of the sound and the low-frequency component of the sound colliding with the inner surface of the outer cylinder 3 are increased, and the attenuation effect of the low-frequency component of the sound is improved. The high frequency component of the sound entering the sound absorbing material storage unit 21 is attenuated by being absorbed by the sound absorbing material 22.

  According to the duct component 1 of the best mode 1, the low frequency component of the sound is attenuated in the air layer 11 and the high frequency component of the sound is absorbed and attenuated by the sound absorbing material 22 in the sound absorbing material storage portion 21. The duct component 1 having an excellent effect can be provided. That is, the duct component 1 that can effectively attenuate both the low frequency component and the high frequency component of the sound can be obtained.

Further, as the duct component 1 installed in the ceiling space with a short vertical length, it is preferable from the viewpoint of exhaust efficiency to increase the inner diameter of the inner cylinder 2 as much as possible to make the exhaust passage thicker. From the viewpoint of sound insulation, it is preferable to increase the area of the inner surface of the outer cylindrical body 3 in contact with the air layer 11 by increasing the air layer 11.
In the best mode 1, the shortest distance dimension between the inner surfaces of the upper and lower flat wall portions 6; 7 of the outer cylindrical body 3 and the outer diameter dimension of the inner cylindrical body 2 are the same. Is formed in a size that can be installed in the ceiling space, the inner diameter of the inner cylinder 2 can be increased and the exhaust passage can be thickened, so that the exhaust efficiency can be improved.
In the best mode 1, since the left and right length W of the outer cylinder 3 is longer than the upper and lower length H, the left and right between the outer surface of the inner cylinder 2 and the inner surface of the outer cylinder 3 as described above. Since the length of the direction can be increased, the volume of the air layer 11 can be increased, and the area of the inner surface of the outer cylinder 3 in contact with the air layer 11 can be increased, the sound insulation effect can be improved. .
Therefore, in the best mode 1, it is possible to obtain the duct component 1 having good exhaust efficiency and high sound insulation effect.

On the other hand, in duct parts as disclosed in Patent Documents 1 to 3, the inner cylinder is formed by a circular cylinder having a perfect cross section and the outer diameter of the inner cylinder is formed by a circular cylinder having a perfect cross section. Since the outer cylinder with a large dimension is arranged coaxially, the outer diameter of the outer cylinder must be formed to a dimension that can be installed in the ceiling space. Therefore, the inner diameter of the inner cylinder must be reduced, and the exhaust passage cannot be thickened.
Further, in the duct parts as disclosed in Patent Documents 1 to 3, since the area of the inner surface of the outer cylinder that is in contact with the air layer does not exceed the area of the inner surface of the outer cylinder having a perfectly circular cross section, the air layer The area of the inner surface of the outer cylinder in contact with can not be increased, and the low frequency component of the sound cannot be effectively attenuated.
Therefore, with the duct parts disclosed in Patent Documents 1 to 3, unlike the duct part 1 of the best mode 1, it is not possible to obtain a duct part with good exhaust efficiency and high sound insulation effect.

In the best mode 1, the left and right lengths W of the outer cylindrical body 3 can be increased regardless of the vertical length of the ceiling space, so that the space between the outer surface of the inner cylindrical body 2 and the inner surface of the outer cylindrical body 3 can be increased. Since the length in the left-right direction can be increased, the volume of the air layer 11 can be increased, and the area of the inner surface of the outer cylinder 3 in contact with the air layer 11 can be increased. Even when the vertical length of the ceiling space is short, the duct component 1 that can be easily installed can be obtained.
On the other hand, in the duct parts as disclosed in Patent Documents 1 to 3, the outer diameter of the outer cylinder cannot be larger than the vertical length of the ceiling space where the duct parts can be installed. The above-mentioned three elements by the duct part 1 cannot be obtained.

  Since the duct part 1 is installed in the ceiling space, the diameter of the outer cylindrical body 3 is formed in consideration of the installation in the ceiling space. Actually, when the vertical length H of the outer cylindrical body 3 of the duct part 1 is set to 250 mm or more, it is considered that the installation of the duct part 1 in the ceiling space is often difficult. Therefore, for example, by setting the upper and lower length H of the outer cylinder 3 to 250 mm or less and the left and right length W of the outer cylinder 3 to 250 mm or more, it is easy to install in the ceiling space and has a sound insulation effect. An excellent duct component 1 can be obtained.

Best form 2
As shown in FIG. 4, rock felt 50 as a sound absorbing material is provided on the inner surfaces of the left and right side wall portions 8: 9 of the outer cylinder 3 in the best mode 1. According to the duct component 1 of the best mode 2, the high frequency component of the sound entering the air layer 11 is absorbed and attenuated by the rock felt 50, so that the high frequency component of the sound can be effectively attenuated.

Best form 3
As shown in FIGS. 5 and 6, instead of the inner cylinder 2 in the best mode 2, an inner part formed by a perforated cylinder in which a plurality of holes 18 are uniformly formed over the entire area of the cylindrical wall of the cylinder. It was set as the structure provided with 2 A of cylinders. According to the duct component 1 of the best mode 2, the low frequency component of the sound that has entered the air layer 11 from the inside of the inner cylinder 2A through the hole 18 of the perforated cylinder forming the inner cylinder 2A is air. Since it attenuates at the layer 11, the low frequency component of the sound can be effectively attenuated.

Best form 4
As shown in FIGS. 7 and 8, instead of the inner cylinder 2 in the best mode 2, a composite inner cylinder 2B is provided. The composite inner cylinder 2 </ b> B is formed by a front inner cylinder 55 and a rear inner cylinder 56. The front inner cylinder 55 is formed by a circular cylinder with a cross-sectional perfect circle shape whose front and rear ends are open and whose front and rear lengths are shorter than the front and rear lengths of the outer cylinder 3, and a plurality of holes 18 are formed in the entire cylindrical wall of the cylinder. It is formed by a perforated cylindrical body that is formed evenly across. The rear inner cylinder 56 is a cylinder whose front and rear ends are open, and is formed in a flat circular shape in which the length in the left-right direction of the front end opening edge 57 is longer than the left and right lengths of the rear end opening edge 58 in the front inner cylinder 55. Is done. The front inner cylinder 55 and the rear inner cylinder 56 are arranged in a state where the axial centers coincide with each other, and the upper part of the rear end opening edge 58 of the front inner cylinder 55 and the upper part of the front end opening edge 57 of the rear inner cylinder 56 are arranged. Are connected to each other, and the lower part of the rear end opening edge 58 of the front inner cylinder 55 and the lower part of the front end opening edge 57 of the rear inner cylinder 56 are connected to each other to form the composite inner cylinder 2B. The upper end of the composite inner cylinder 2B and the center between the left and right sides of the inner surface of the flat wall portion 6 on the outer cylinder 3 are connected to each other, and the lower end of the composite inner cylinder 2B and the flat wall portion below the outer cylinder 3 are connected. 7 is connected to the center between the left and right sides of the inner surface. By the above, between the rear-end opening edge 58 of the front inner cylinder 55 and the front-end opening edge 57 of the rear inner cylinder 56, the air circulation part 59 opened to the inside of the rear inner cylinder 56 and the air layer 11 is established. Is formed. In the duct component 1 of the best mode 4, the sound that has entered the inside of the front inner cylindrical body 55 from the front side of the front side connecting portion 28 enters the air layer 11 via the plurality of holes 18 and is rearward of the rear side connecting portion 29. The sound that has entered the inside of the rear inner cylinder 56 from the side enters the air layer 11 through the air circulation portion 59 and the plurality of holes 18 of the front inner cylinder 55. Since the low-frequency component of the sound that has entered the air layer 11 is attenuated by the air layer 11 and the high-frequency component of the sound that has entered the air layer 11 is attenuated by being absorbed by the rock felt 50, the low-frequency component of the sound In addition, high frequency components can be effectively attenuated. Further, since the rear inner cylinder 56 is formed of a non-hole cylinder, the pressure loss in the duct component can be reduced. Therefore, the duct component 1 having a high sound insulation effect and a small pressure loss can be obtained.

Best form 5
5; 6, an open cell sheet (not shown) is wound around the outer peripheral surface of the inner cylindrical body 2A of the best mode 3 in FIG. 6, and a rock felt 50 as a sound absorbing material is provided on the inner surfaces of the left and right cylindrical wall portions 8; It was set as the structure which does not provide. The open cell sheet is formed of a metal fiber laminate having open cells. The metal fiber laminate is formed by pressing metal scraps such as aluminum scraps and stainless scraps into a plate shape. In this fiber laminated board, open cells are formed such that a narrow space continues stepwise in the thickness direction of the board. According to the duct component 1 of the best mode 5 configured by wrapping the fiber laminate having such open cells around the outer peripheral surface of the inner cylindrical body 2A, the fiber lamination is performed when the high frequency component of the sound passes through the open cells. By colliding with the base material of the plate (sheet base material of the open cell sheet), the collision part vibrates and the high frequency component of the sound is attenuated, and the fiber laminate and the inner cylinder 2A vibrate due to the sound pressure. The low frequency component of the sound is attenuated by this plate vibration. Furthermore, since the low frequency component of the sound enters the air layer 11 which is a large space from the open bubbles which are a small space, the sound is efficiently attenuated. Moreover, since it is reduced that air flows into the air layer 11 from the inner side of the inner cylindrical body 2A, pressure loss can be reduced. Therefore, it is possible to obtain the duct component 1 having more excellent sound insulation effect and pressure loss prevention effect.

Best form 6
In the duct component 1 of the best mode 5, the duct component 1 is configured such that a rock felt 50 as a sound absorbing material is provided on the inner surfaces of the left and right cylinder wall portions 8: 9 of the outer cylinder 3. According to the duct component 1 of the best form 6, since the high frequency component of the sound that has entered the air layer 11 is absorbed and attenuated by the rock felt 50, the damping effect of the high frequency component is higher than that of the duct part 1 of the best form 5. it can.

  For example, the rock felt 50 is provided to extend back and forth across the front and rear ends of the outer cylinder 3 and has a thickness of 20 mm. For example, the front and rear lengths of the front inner cylinder 55 are 350 mm, and the front and rear lengths of the rear inner cylinder 56 are 200 mm. For example, the front perforated cylindrical portion 15, the rear perforated cylindrical portion 16, the inner cylindrical body 2A, and the front inner cylindrical body 55 are formed of a punching iron plate, and the aperture ratio of the plurality of holes 18 is 58%. In addition, the duct parts of the best modes 5 and 6 used in the experiments described below were formed by winding an aluminum foil fiber laminate as an open cell sheet around the entire outer peripheral surface of the inner cylinder 2A.

As the duct parts 1 according to the best form 1 to the best form 6, those having a left and right length W of the outer cylindrical body 3 of 360 mm and 500 mm are prepared, and these duct parts 1 are used. An experiment was conducted to measure the sound pressure level attenuation (dB).
The experiment was carried out using the experimental apparatus shown in FIG. That is, the front connection part 28 (see FIG. 1) of the duct part 1 as a test body and the rear end part of the front cylindrical tube 61 having an inner diameter of 150 mm are connected to each other, and the rear connection part 29 (see FIG. 1). ) And the front end portion of the rear cylindrical tube 62 having an inner diameter of 150 mm are connected to each other, one end of a sound tube 63 for taking in sound is connected to the front portion of the front cylindrical tube 61, and a sound source speaker 64 is disposed on the other end of the sound tube 63. The noise generated by the noise generator 65 is amplified by the amplifier 66 and input to the sound source speaker 64. A non-reflection end 66 is formed at the front end of the front cylindrical tube 61, and a non-reflection end 67 is formed at the rear end of the rear cylindrical tube 62. The non-reflective end 66 has two glass wools with a density of 96 kg / m ³ and a thickness of 50 mm, not shown, and a density of 48 kg / m from the front end of the cylinder toward the side where the duct part 1 is located inside the front cylindrical tube 61. ³ and 2 glass wool with a thickness of 50 mm and 2 glass wool with a density of 24 kg / m ³ and a thickness of 50 mm were laminated in that order. The non-reflective end 67 was formed in the same manner. The sound pressure level attenuation (dB) is measured by installing a microphone 68 inside the front cylindrical tube 61 that is a predetermined distance a forward from the front end of the duct part 1 and at a predetermined rearward position from the rear end of the duct part 1. After a distance b, a microphone 69 is installed inside the cylindrical tube 62, and the sound pressure levels of the sounds collected by the microphones 68; 69 are individually measured by sound level meters (with frequency analysis function) 70; 71, The difference between the sound pressure level on the front side of the duct part 1 and the sound pressure level on the rear side of the duct part 1, that is, the sound pressure level attenuation amount was obtained. The predetermined distance a and the predetermined distance b are the same distance, and the predetermined distance a: b is directed from the duct part 1 toward the non-reflective end 66; 67 between the point x of 0 mm and the point y of 1000 mm at every 100 mm interval. The sound pressure level attenuation is measured at each of 11 corresponding pairs at the same distance from the duct part 1 before and after the duct part 1, and the average value of the attenuation at each of the 11 parts. Was taken as the measurement result. Numbers other than the reference numerals in FIG. 9 indicate dimensions, and the unit is mm.
In addition, as Comparative Example P, the same measurement was performed when a cylindrical tube having a length of 1000 mm having a sound absorbing material having a thickness of 20 mm on the inner peripheral surface of the tube was connected to the duct part 1 in FIG. The cylindrical tube is formed so that the diameter of the tube is the same as that of the front cylindrical tube 61 and the rear cylindrical tube 62, and the front and rear end portions are formed to fit the front cylindrical tube 61 and the rear cylindrical tube 62. Thus, the front and rear end portions were fitted and connected to the front cylindrical tube 61 and the rear cylindrical tube 62.
FIG. 10 shows the measurement results of the duct component 1 and the comparative example P according to the best mode 1 to the best mode 6.

  The sound insulation effect of the duct component 1 according to the best modes 1 to 6 will be described with reference to FIGS. In addition, the numerical value on the left side shown in the column of the form of the duct part in FIG. 10 indicates the number of the best form, and the number in parentheses on the right side indicates the left and right length W of the outer cylinder 3. In FIG. 11, the results of the duct component 1 according to the best modes 1 to 6 when the left and right length W of the outer cylindrical body 3 is set to 360 mm are collectively shown in the graph. In FIG. 12, the results of the duct parts 1 according to the best modes 1 to 6 when the left and right length W of the outer cylinder 3 is 500 mm are collectively shown in the graph.

In the case of W = 360 mm, the sound insulation effect of the duct component 1 of the best mode 1: 2 is excellent. Since the duct part 1 of the best mode 1 includes the sound absorbing material portion 20 and the air layer 11, the sound pressure level attenuation amount for the sound of the high frequency component of 500 Hz or more and the sound pressure for the sound of the low frequency component of 500 Hz or less. Excellent level attenuation. In the duct component 1 of the best mode 2, since the rock felt 50 is further provided, the sound pressure level attenuation amount with respect to the sound of the high frequency component of 500 Hz or more is excellent.
In the case of W = 500 mm, since the area of the inner surface of the outer cylindrical body 3 in contact with the air layer 11 is larger than that in the case of W = 360 mm, the attenuation effect of the low frequency component of the sound entering the air layer 11 is improved.
Incidentally, the attenuation of 125 Hz band in the duct part 1 of the best form 6 when W = 360 mm is 3.7 dB, and the attenuation quantity of 125 Hz band in the duct part of the best form 1 when W = 500 mm is 3 .5 dB, which is slightly worse than Comparative Example P, but is a measurement error. The engineering performance is almost the same as Comparative Example P. Other than that, the sound insulation effect is superior to Comparative Example P.

  Duct components 1 as shown in FIGS. 13 to 15 are also within the scope of the present invention. FIG. 13 shows a duct component 1 having a configuration in which the sizes of the air layers 11 on both the left and right sides of the inner cylinder 2 are different. FIG. 14 shows a duct component 1 having a configuration in which an air layer 11 is formed only on either the left or right side of the inner cylinder 2. FIG. 15 shows a duct component 1 having a configuration in which the upper and lower lengths H of the outer cylindrical body 3 are made larger than the outer diameter dimension of the inner cylindrical body 2 to form an air layer 11 continuous in the vertical and horizontal directions of the inner cylindrical body 2. Even in the duct part 1 configured as described above, the left and right lengths W of the outer cylinder 3 are longer than the upper and lower lengths H of the outer cylinder 3, so that the outer surface of the inner cylinder 2 and the outer cylinder 3 can be increased in length in the left-right direction, the volume of the air layer 11 can be increased, and the area of the inner surface of the outer cylinder 3 in contact with the air layer 11 can be increased. This is because the sound insulation effect can be improved.

(A) is the perspective view of a duct component, (b) is the figure which looked at the duct component from the front side (best form 1). Sectional drawing of a duct component (the best form 1). The figure which shows the example of installation of an exhaust duct (best form 1). The perspective view of a duct component (best form 2). The perspective view of a duct component (best form 3). Sectional drawing of duct components (best form 3). The perspective view of a duct component (best form 4). Sectional drawing of duct components (best form 4). The figure which shows the experimental apparatus which measured the sound pressure level attenuation amount of the duct components (the best form 1 thru | or 6 and a comparative example). The table | surface which shows an experimental result (best form 1 thru | or 6 and a comparative example). The graph which shows an experimental result (best form 1 thru | or 6 and a comparative example). The graph which shows an experimental result (best form 1 thru | or 6 and a comparative example). The figure which shows the other example of a duct component. The figure which shows the other example of a duct component. The figure which shows the other example of a duct component.

Explanation of symbols

1 Duct component, 2; 2A Inner cylinder, 3 Outer cylinder, 4 Occlusion body, 5 Connecting part,
6; 7 flat wall part, 10 connection part, 11 air layer, 15 front perforated cylinder part,
16 rear perforated cylindrical part, 17 non-perforated cylindrical part, 18 holes, 20 sound absorbing material part,
34 Unit duct parts (other duct parts), 55 Front inner cylinder,
56 Rear inner cylinder.

Claims (1)

The outer cylinder, the inner cylinder provided inside the outer cylinder, and the end of the outer cylinder and the end of the inner cylinder at the front and rear ends of the outer cylinder and the inner cylinder An outer cylinder that includes a closed body that seals between the end of the outer cylinder and the end of the inner cylinder in a sealed state, and an air layer that is surrounded by the outer cylinder, the inner cylinder, and the outer body. The body is formed such that the length in the left-right direction of the cylinder relative to the front-rear direction of the cylinder is longer than the length in the vertical direction of the cylinder, and the inner cylinder has a front perforated cylinder portion formed at the front end of the cylinder, A rear perforated tube formed at the rear end of the tube, a non-perforated tube formed at the center of the tube between the front perforated tube and the rear perforated tube, and a rear perforated tube A sound-absorbing material portion provided on the outer peripheral side of the hole tube portion, the sound-absorbing material portion comprising a sound-absorbing material storage portion that is blocked from the air layer, and a sound-absorbing material stored in the sound-absorbing material storage portion. A compound in which the hole cylinder part penetrates between the inside of the inner cylinder and the air layer. Comprising a hole, duct part, characterized in that it comprises a plurality of holes penetrating across the interior of the inner and sound absorbing material housing portion of the rear side perforated tubular portion inner cylinder.

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