JP2007016652A - Intake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake device (or a muffling device) having high muffling performance in rebound frequency range even if provided with a resonator and providing high muffling performance over all frequency range from a low frequency range to a high frequency range. <P>SOLUTION: The suction device is provided with an expansion noise absorbing unit 1 provided with noise absorbing material and an expansion chamber 9 around a gas flow passage, and a helmholtz type resonance unit 4 adjoining the expansion noise absorbing unit and communicating to the gas flow passage. A bulkhead 6 partitioning the expansion noise absorbing unit 1 and the resonance unit 4 is provided. A communication part 7 for establishing communication between the expansion noise absorbing unit 1 and the resonance unit 4 is formed on the bulkhead. The communication part 7 can be a hole or porous vent holes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an intake device (or a silencer) that can be used for an internal combustion engine such as an automobile or a generator and has a high silencing property in all frequency ranges from a low frequency to a high frequency.

  In order to reduce noise generated from an internal combustion engine such as an automobile (gasoline engine, diesel engine, etc.), various intake devices including a sound absorption duct and a Helmholtz resonator are used. Japanese Utility Model Publication No. 63-2597 (Patent Document 1) discloses a resonance silencer comprising a gas passage through which noise is propagated and a resonance chamber communicating with the gas passage. A gas passage is formed in one half of the hollow body, and a cylindrical connecting portion extending over a predetermined length in the hollow body is formed in the gas flow path, and an opening portion of the connecting portion is formed. In addition, there is disclosed a silencer in which a cylindrical neck portion for communicating a gas passage and a hollow body is attached via a flange portion. Since this silencer is a resonance type, it exhibits a high silencing effect against low frequency noise. However, not only can the noise in the high frequency range be effectively silenced, but the resonator has a rebound frequency in the vicinity of the set frequency, and the silencing performance is greatly reduced in the rebound frequency region.

  JP-A-4-321896 (Patent Document 2) includes a woven fabric liner, a material that reinforces the liner, and an elastomeric sound absorbing outer layer that is extruded and bonded to the woven fabric liner. An integral air intake duct having sound attenuation and silencing properties is disclosed in which the sound absorbing outer layer is formed of an ethylene propylene terpolymer (Claims). Japanese Patent Application Laid-Open No. 2003-343373 (Patent Document 3) discloses that an air duct having a part or all of a pipe wall formed of a porous material having air permeability and introducing the outside air into an internal combustion engine includes the air permeability. An air intake duct that covers a part or all of the pipe wall so as to have an air layer between the pipe wall and the pipe wall that is formed of a porous material having a gas is disclosed (patent) The scope of the claims). Since this air intake duct is composed of a woven fabric liner or a porous material, it exhibits a silencing effect mainly for high-frequency noise, but it cannot effectively mute low-frequency noise.

In Japanese Patent Laid-Open No. 9-144986 (Patent Document 4), in a sound absorbing duct structure having a base duct and an expanded portion having an inner diameter larger than that of the duct, a sound absorbing material is provided in the length direction or the cross-sectional direction inside the expanded portion. There is disclosed a sound absorbing duct structure in which an extended sound absorbing duct portion in which the horn is disposed and a Helmholtz resonator portion are structurally integrated (claims). In this sound absorbing duct structure, sound absorbing properties are exhibited in the entire frequency range from low frequencies to high frequencies, and a reduction in the silencing effect near the rebound frequency of the Helmholtz resonator can be suppressed. However, if the effect of the Helmholtz resonator is increased due to an increase in the size of the resonator, for example, the silencing performance in the rebound frequency range is inevitably lowered, and the noise level cannot be lowered in the rebound frequency range. Therefore, when it is necessary to increase the size of the resonator, in order to compensate for the lack of the silencing effect at the rebound frequency, the sound absorbing duct structure must be increased in size, and the entire silencing device cannot be increased in size. .
Japanese Utility Model Publication No. 63-2597 (request for utility model registration) JP-A-4-321896 (Claims) JP 2003-343373 A (Claims) JP 9-144986 A (claims, paragraph numbers [0052] [0053])

  Accordingly, an object of the present invention is to provide an intake device (or a silencer) that has a high resilience in the rebound frequency range even if a resonator is provided.

  Another object of the present invention is to provide an intake device (or a silencer device) that not only has a high silencing performance in the rebound frequency range but also a high silencing performance in the entire frequency range from the low frequency range to the high frequency range. There is.

  Still another object of the present invention is to provide an air intake device (or a muffler device) that can realize high noise reduction with a simple structure even if it is small.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors formed a communication part (or a ventilation part) in the partition wall between the Helmholtz resonator and the sound absorption duct, and the resonance and the sound absorption duct communicated with each other. The present invention has been completed by finding that it is possible to improve the silencing performance in the rebound frequency range even if it is equipped with a device, and to obtain high silencing performance in the entire frequency range from the low frequency range to the high frequency range.

  That is, the intake device (or the sound absorption device) of the present invention is located adjacent to the extended sound absorption unit, including the sound absorption material and the expansion chamber around the gas flow channel, and communicates with the gas flow channel. Helmholtz type resonance unit. In the present invention, the intake device is configured by forming a communication portion (or a ventilation portion) for communicating the extended sound absorption unit and the Helmholtz resonance unit. The communication part may be formed in a partition wall for partitioning the extended sound absorbing unit and the Helmholtz resonance unit.

  In such a device, the function of the communication portion can prevent a reduction in the silencing effect in the rebound frequency range of the Helmholtz-type resonance unit (or resonator) and reduce noise in the rebound frequency range. In addition, an extended sound absorbing unit (or a sound deadening unit) equipped with a sound absorbing material (or a sound deadening material) effective for sound silencing in a high frequency range is combined with a Helmholtz type resonance unit, so a wide frequency range from low to high frequencies. Can improve muffler. Furthermore, the silencing performance can be improved with a simple structure in which a communication part is formed between the extended sound absorbing unit and the resonance unit or a partition wall having a communication part is formed.

  The communication part may be a hole or a porous air hole. The communication portion may be formed at an appropriate position of the partition wall, for example, at a vertically lower part (or a lower partition wall), and formed at an intersection of the partition wall and the outer wall of the Helmholtz resonance unit or the extended sound absorption unit. However, it may communicate with the outside. Furthermore, the partition wall may support the extended sound absorbing unit via the air-permeable porous body.

  The present invention relates to an extended sound absorbing unit having a sound absorbing material and an expansion chamber around a gas flow path, and a Helmholtz type resonance unit located adjacent to the extended sound absorption unit and communicating with the gas flow path. A method for reducing noise by forming a communication portion for communicating the extended sound absorbing unit and the Helmholtz resonance unit between the extended sound absorption unit and the Helmholtz resonance unit. The method of doing is also included.

  In the present invention, since the capacity portion of the resonator and the sound absorbing material region of the sound absorbing duct are acoustically connected by the communication portion or the ventilation portion, resonance in the resonator can be suppressed. For this reason, even if a resonator is provided, it is possible to prevent a reduction in muffling performance in the rebound frequency range. Moreover, not only the sound deadening property in the rebound frequency range is high, but also high sound deadening property can be obtained in the entire frequency range from the low frequency range to the high frequency range. In particular, the capacity part of the sound absorbing duct is communicated with the capacity part of the resonator, and the configuration is the same as that in which a back air layer is formed on the sound absorbing material of the sound absorbing duct, and the silencing property can be improved particularly in a low frequency range. Furthermore, even if it is small, high sound deadening property is realizable with the simple structure of forming a communication part or a ventilation part.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

    FIG. 1 is a schematic longitudinal sectional view showing an example of an intake device of the present invention. The intake device (silencer) of this example includes a cylindrical Helmholtz resonance unit (or resonator, resonance type silencer unit) 4 and a cylindrical gas flow path 2 that passes through the resonance unit coaxially. . The gas flow path 2 includes a porous cylinder (sound absorbing material) 3 which is a cylinder having a continuous air hole such as a so-called porous duct formed in a part in the axial direction, a resin connected to both ends thereof, and the like. It is comprised by the non-porous cylinder 8 and 8 which consist of. In the resonance unit 4, the extended sound absorbing unit 1 includes a porous cylinder 3 as a sound absorbing material and an outer diameter (diameter) larger than that of the nonporous cylinders 8 and 8 on the outside thereof, and a gas flow path extends in the radial direction. It is composed of an extended expansion chamber 9. In other words, the intake device has a structure in which the extended sound absorption unit 1 is coaxially disposed in a cylindrical Helmholtz resonance unit (or resonance type silencer unit) 4. In addition, you may make it coat | cover porous materials, such as a fiber assembly, as a sound absorption material on the outer side of the porous cylinder 3 as a sound absorption material.

    A partition wall 6 for partitioning the resonance unit 4 and the extended sound absorbing unit 1 is formed in the resonance unit 4. The partition wall 6 is formed of a cylindrical body that extends in a downstream direction from the upstream side wall of the resonance unit 4 and is closed on the downstream side of the extended sound absorbing unit 1. An air layer is formed on the outside through the material cylinder 3, and the peripheral wall of the resonance unit 4, the partition wall 6, and the gas flow path 2 is formed in a triple tubular shape. A cylindrical neck portion (tubular portion) 5 extending into the resonance unit 4 is formed in the cylindrical body 8 on the downstream side of the partition wall 6 to constitute a resonator (resonance type silencer). The expanded sound absorbing unit 1 is connected to the gas flow path 2 formed by the porous cylinder 3 and the non-porous cylinders 8 and 8 so as to surround the gas flow path 2, and the resonance unit 4 is connected to the neck (cylinder). Connection) 5.

  A communication hole is formed in the central portion of the partition wall 6 in the longitudinal direction (or the axial direction), and a communication portion (for example, an air communication portion that communicates acoustically) 7 connects the extended sound absorbing unit and the resonance unit. Is configured. That is, the capacity part of the extended sound absorbing unit 1 and the capacity part of the resonance unit 4 communicate with each other through the communication hole 7 formed in the lower partition wall of the partition wall 6.

  In the intake device (silencer) having such a structure, the noise in the high frequency range among the noise propagating through the gas flow path can be effectively silenced by the extended sound absorption unit 1 having the sound absorbing material 3. Further, in the resonance unit 4, a resonance chamber is formed by the cylindrical neck portion (tubular portion) 5 and the space in the resonance unit 4, and noise in a low frequency range propagating through the gas flow path is reduced by the action of the resonator. Is done. On the other hand, in the resonance unit 4, the noise near the rebound frequency increases. However, since the communication part 7 is formed in the partition wall 6, the capacity part of the resonance unit 4 is connected to the sound absorbing material 3, the resonance in the resonance unit 4 is suppressed, and the sound can be effectively silenced even in the rebound frequency range. . Furthermore, an expansion chamber (an air layer behind the sound absorbing material) 9 that forms a space existing between the back surface of the sound absorbing material 3 and the partition wall 6 by the communication portion 7 formed in the partition wall 6 is an area of the capacity unit of the resonance unit. Therefore, it is possible to improve the silencing performance of the sound absorbing unit against noise (especially in the low frequency range). Therefore, noise can be effectively removed from the low frequency range to the high frequency range. In the device, even if water enters the gas flow path (duct) 2, the resonance unit 4 and the extended sound absorption unit 1 function as a buffer unit, and drain the communication hole 7 formed in the lower partition wall. It can be used as a hole.

  More specifically, as in the sound absorption characteristics shown in FIG. 2, when the resonator is used compared to the case where the resonator is not used (A), a remarkable silencing effect can be obtained at the set frequency of the resonator (B ). However, with the resonator alone, the silencing effect is remarkably reduced in the rebound frequency range near the set frequency (low frequency range) (C). On the other hand, as shown in FIG. 3, when the sound absorbing duct (extended sound absorbing duct) and the resonator are integrated (E) as compared with the case where the sound absorbing duct (extended sound absorbing duct) is alone (D), the resonance of the resonator. The silencing effect can be improved in frequency. However, a rebound frequency with a low silencing effect exists in the vicinity of the resonance frequency of the resonator, and the silencing effect is not yet sufficient at that frequency. Therefore, as shown in FIG. 4, if the effect of the Helmholtz resonator is increased by increasing the size (F), the reduction in the silencing effect in the rebound frequency range also increases, the noise level increases, and the low frequency range. The noise reduction effect cannot be improved. In addition, the silencing effect (attenuation characteristic with respect to a predetermined frequency) by the resonator can be adjusted by the inner diameter and length of the resonator as shown by the following formula.

  In the formula, fr is the set frequency to be attenuated, c is the speed of sound, S is the cross-sectional area of the neck of the resonator, L is the length of the neck of the resonator, and V is the volume of the capacitive portion of the resonator.

  On the other hand, as shown in FIG. 5, the silencing effect of the resonator unit according to the present invention is larger than that of the resonator alone (B) by forming a communicating portion in the partition wall. In addition, it is possible to effectively prevent a reduction in the silencing effect in the rebound frequency range of the resonator, and to effectively attenuate noise in the low frequency range (G1). Further, as shown in FIG. 6, the sound absorbing effect of the sound absorbing unit according to the present invention is due to the noise (particularly the noise in the low frequency range) because the space (back air layer) is formed and enlarged with respect to the sound absorbing material. The silencing effect can be improved (G2). 7 shows a silencing characteristic (G3 = G1 + G2) obtained by superimposing FIG. 5 and FIG. 6, and the apparatus according to the present invention as compared with an apparatus (F) in which a sound absorbing duct and a large resonator are integrated. Shows a high silencing property in a wide wavelength range as indicated by G3.

  FIG. 8 is a schematic cross-sectional view showing another example of the intake device of the present invention. In this example, a communicating portion (breathable communicating portion) is formed of a breathable porous material. That is, the extended sound absorbing unit 11 includes a part in which a plurality of holes 18 are formed in the peripheral wall in a part in the axial direction of the non-breathable cylindrical body 12 constituting the duct body, and a cotton-like shape disposed around the part. In the same manner as described above, the cylindrical body 12 forming the gas flow path penetrates the resonance unit (or resonator) 14 in the axial direction and expands the gas flow path through the hole 18. The extended chamber 19 is formed.

  Further, a neck portion (cylindrical portion) 15 constituting the resonance unit 14 extends into the resonance unit 14 on the downstream side of the expanded sound absorbing unit 11 in the cylindrical body 12. The sound absorbing material 13 is filled in a cylindrical partition wall 16 that isolates the extended sound absorbing unit 11 and the resonance unit 14 and is closed on the downstream side. , The lower partition wall) forms a communication portion or a ventilation portion 17 made of a breathable porous material (for example, a nonwoven fabric).

  In such an intake device, in addition to the same function and effect as the device shown in FIG. 1, the communication portion 17 that connects the capacity portions of the extended sound absorbing unit 11 and the resonance unit 14 is made of a breathable porous material. Therefore, the noise due to the rebound frequency in the resonance unit 14 can be further reduced.

  FIG. 9 is a schematic cross-sectional view showing still another example of the intake device of the present invention, and FIG. 10 is a schematic perspective view showing the communicating portion of FIG. In this example, a communication portion is formed at the intersection of the outer wall of the resonance unit and the partition wall. That is, the extended sound absorbing unit 21 includes a cylindrical gas flow path 22 inside, and the gas flow path 22 is a porous body having a continuous air hole such as a porous duct formed in a part in the axial direction. An expansion chamber defined by an outer wall 30 on the outside of the porous cylinder 3, which is composed of a material cylinder (sound absorbing material) 23 and non-porous cylinders 28, 28 made of resin or the like connected to both ends thereof. 29 is formed. A gas flow path 22 formed by the porous cylinder (sound absorbing material) 23 and the non-porous cylinders 28 and 28 penetrates the resonance unit 24 in the axial direction. In the capacity portion of the resonance unit 24, a neck portion (cylindrical portion) 25 extends downward from the cylindrical body 22. A partition wall 26 that divides the resonance unit 24 in the radial direction is formed on the downstream side of the extended sound absorbing unit 21, and an intersection portion of the partition wall 26 and the resonance unit 24 (in this example, a vertically lower portion or a lower end portion of the partition wall). ) Is formed with a communication part (communication hole or notch part) 27, and the communication part 27 communicates with the outside.

  In such an intake device, similarly to the device shown in FIG. 1, the capacity unit of the resonance unit 24 is connected to the sound absorbing material 23, the resonance in the resonance unit 24 is suppressed, and the sound can be effectively silenced even in the rebound frequency range. . Further, the communication chamber 27 formed in the partition wall 26 expands the expansion chamber 29, which is a space (back air layer) existing between the back surface of the sound absorbing material 23 and the partition wall 26, to the capacity portion region of the resonance unit 24. Therefore, it is possible to improve the sound deadening property of the sound absorbing unit against noise (particularly noise in a low frequency range). Moreover, the communication part 27 formed in the lower part (vertical direction lower part) of the partition wall 26 can also be utilized as a drain hole.

  FIG. 11 is a schematic cross-sectional view showing another example of the intake device of the present invention, and FIG. 12 is a schematic cross-sectional view showing the communication portion or the support portion of FIG.

  In this example, in the intake device, the extended sound absorbing unit is supported by a partition wall that partitions the extended sound absorbing unit and the resonance unit, and a breathable porous body is interposed between the extended sound absorbing unit and the partition wall. That is, the extended sound absorption unit 31 includes a cylindrical gas flow path 32 inside, and the gas flow path 32 is a porous body having a continuous air hole such as a porous duct formed in a part in the axial direction. An expansion chamber that is constituted by a non-porous cylinder 38, 38 made of a material cylinder (sound absorbing material) 33 and resin or the like connected to both ends thereof, and is partitioned by an outer wall 40 outside the porous cylinder 3 39 is formed. A gas flow path 32 formed by the porous cylinder (sound absorbing material) 33 and the non-porous cylinders 38 and 38 passes through the resonance unit 34 in the axial direction. In the capacity portion of the resonance unit 34, a neck portion (cylindrical portion) 35 extends upward from the non-porous cylindrical body 38. A partition wall 36 is formed at the downstream end of the extended sound absorbing unit 31 to partition the capacitive portion of the resonance unit 34 in the radial direction (longitudinal direction). The partition wall 36 forms a porous cylindrical body (porous duct) 33. I support it. For this reason, an air-permeable communicating portion 37 composed of the porous cylinder 33 is formed between the partition wall 36 and the non-porous cylinder 38, and the extended sound absorbing unit 31 and the resonance unit 34 are acoustically connected. ing. In this example, the partition wall 36 supports a connecting portion between the porous cylinder 33 and the non-porous cylinder 38.

  In such an apparatus, the expansion sound absorption unit 31 and the capacity part of the resonance unit 34 are connected via the air-permeable communication part 37, resonance in the resonance unit 34 is suppressed, and sound can be effectively silenced even in a rebound frequency range.

  Note that the extended sound absorbing unit includes a gas flow path therein, a sound absorbing material (for example, a sound absorbing material capable of attenuating high frequency noise), and an expansion chamber in which the inner diameter of the gas flow path is expanded. In the extended sound absorbing unit, the gas flow path can be composed of at least a sound absorbing cylindrical body, and may be composed of a sound absorbing porous cylindrical body alone or may be sound absorbing and disposed around the cylindrical body. You may comprise with the sound-absorbing material. Further, the length of the extended sound absorbing unit may be, for example, about 1 to 100 cm (for example, 5 to 75 cm, preferably 10 to 50 cm) depending on the application.

  In addition, the cylinder which forms a gas flow path usually extends from the sound absorption unit and penetrates the resonance unit. In particular, the cylindrical body often extends coaxially from the sound absorbing unit and passes through the resonance unit coaxially.

  The expanded sound absorbing unit is a breathable porous cylinder such as a breathable cylinder or a sound absorbing cylinder (such as a cylinder formed with a breathable hole (pores) or a cylinder (such as a porous duct) made of a porous material). ) May constitute a gas flow path, and may be constituted by such a gas permeable cylinder and a sound absorbing material disposed or covered in a portion corresponding to the sound absorbing portion of the cylinder, You may comprise by the formed non-air-permeable cylinder (porous cylinder) and the sound-absorbing material arrange | positioned in the formation part of the hole of this cylinder. For example, the cylinder constituting the extended sound absorption unit may be constituted by a porous duct, a fiber duct (nonwoven fabric or woven fabric), etc., a cylinder constituted by a synthetic resin foam having open cells, It may be a cylindrical body in which a synthetic resin foam tape having open cells is spirally wound around a porous or non-porous cylindrical body having holes formed in the peripheral wall.

The sound-absorbing material is a variety of sound-absorbing materials such as fiber aggregates (natural fibers, semi-synthetic fibers such as acetate fibers, polyethylene fibers, polypropylene fibers, polyester fibers, polyamide fibers, acrylic fibers, etc., glass fibers , Fiber aggregates of inorganic fibers such as carbon fibers), non-woven fabrics (non-woven fabrics formed by needle punching, dry or wet methods, non-woven fabrics formed of fibers including heat-sealing fibers), woven fabrics, open cells Synthetic resin foams (foamed polyethylene resin, foamed ethylene-vinyl acetate copolymer, foamed polyurethane, etc.), and synthetic resin foam tapes with open cells (foamed polyethylene resin tape, foamed ethylene-vinyl acetate copolymer tape) Etc.). Incidentally, the basis weight of the sound absorbing material, 50~4000g / m ^2, preferably 100 to 3000 g / m ^2, more preferably about 150~1500g / m ^2.

  The extended sound absorbing unit and the resonance unit need only be connected to or communicated with the gas flow path, and the extended sound absorption unit and the resonance unit may be formed separately, but are usually formed integrally. . In many cases, the extended sound absorbing unit is usually disposed in the resonance unit. The cross-sectional shape of the extended sound absorbing unit is not limited to a cylindrical shape, and may be various shapes such as an elliptical shape and a polygonal shape. The extended sound absorbing unit need not be arranged coaxially with the resonance unit, and the axes of the extended sound absorbing unit and the resonance unit may be offset from each other.

  The Helmholtz type resonance unit only needs to be able to attenuate sound wave energy by resonance absorption, and a resonator (resonance type silencer) having various necks such as a single hole type, a slit type, and an insertion type can be used. The neck of the resonance unit extends into the resonance unit, and may extend from the cylindrical body of the sound absorption unit in various directions, for example, in the vertical direction and the side. As described above, the predetermined frequency can be effectively attenuated by adjusting the inner diameter and length of the neck and the capacity of the resonance unit. Therefore, the size of the neck can be selected according to the frequency to be attenuated (set frequency). The cross-sectional shape of the neck is not limited to a cylindrical shape, and may be an elliptical shape, a polygonal shape, or the like. The cross-sectional shape of the resonance unit is not limited to a cylindrical shape, and may be various shapes such as an elliptical shape and a polygonal shape. Also, the inner diameter and / or length of the resonance unit can be selected according to the set frequency.

  As long as the extended sound absorbing unit and the resonance unit communicate with each other through the communication portion, the partition wall is not always necessary. For example, the expansion sound absorption unit and the resonance unit only have to communicate with or ventilate their respective capacity portions, and in the gas flow path, the expansion sound absorption unit and the resonance unit disposed adjacent to the expansion sound absorption unit, You may comprise by the communication part (For example, the communication part comprised by the cylinder which connects an expansion sound absorption unit and a resonance unit) which connects the capacity | capacitance part of an expansion sound absorption unit, and the capacitance part of a resonance unit. In many cases, the communication portion is formed in a partition wall for partitioning the extended sound absorbing unit and the resonance unit. Further, the resonance unit and the extended sound absorption unit need only be adjacent to each other, and may be located upstream and / or downstream in relation to each other.

  The partition wall can be formed in various modes as long as the extended sound absorbing unit and the resonance unit are shielded (sectioned or isolated), and the peripheral wall extending in the axial direction in the upstream direction from the downstream side wall of the resonance unit and the end of the peripheral wall are closed. A hollow cylindrical tube (both ends closed) that surrounds the extended sound absorbing unit in the resonance unit and is supported (supported directly or via a support) by the peripheral wall of the resonance unit. Cylinder). Moreover, the partition may be in contact with the extended sound absorbing unit as in the above example, or may be separated from the extended sound absorbing unit.

  Note that the communication part is only required to acoustically connect the capacity part of the sound absorption unit and the capacity part of the resonance unit to attenuate noise (especially noise due to rebounding in the low frequency range), and is formed at an appropriate position of the partition wall. May be. Further, the communication part may be formed at the intersection of the partition wall and the outer wall of the resonance unit or the extended sound absorption unit, and the communication part may communicate with the outside. For example, a communication part that communicates the capacity part of the extended sound absorbing unit and the capacity part of the resonance unit may be formed on the partition wall, and a communication part that communicates with the outside may be formed on the outer wall of the acoustic unit. If the communicating part is formed in the lower part of the vertical direction or the lower part of the partition wall (including the intersection of the outer wall of the resonance unit and the partition wall), the communicating part that leads to the outside is used as a drain hole to efficiently remove intrusion water. it can. Moreover, a communication part can be formed in the peripheral wall extended in an axial direction and / or the peripheral wall extended in a radial direction among partition walls, and this communication part can be formed in one or several places. Further, the shape of the communication portion is not particularly limited, and may be a circular shape, an elliptical shape, a polygonal shape, an indefinite shape, or the like, and the communication portion may extend in the circumferential direction or in the radial direction. . When forming a communication part in several places, you may form a communication part regularly or randomly in the appropriate place of a partition.

  The communication part may be a hole (or an opening) or may be formed of a porous ventilation hole. Similar to the sound absorbing material, the porous vent can be composed of a fiber assembly, a nonwoven fabric, a woven fabric, a synthetic resin foam having open cells, a synthetic resin foam tape or sheet having open cells.

  The partition wall may support the cylindrical body directly (that is, in a form of contact or non-contact with the extended sound absorption unit), and the air-permeable porous body (nonwoven fabric, woven fabric, sponge having open cells or An extended sound absorbing unit (a cylinder or a sound absorbing material) may be supported via a foam, a fiber assembly, a sound absorbing material, or the like.

  The surface of the sound absorbing material of the extended sound absorbing unit may be open or exposed, and the sound absorbing material is encapsulated with a porous sheet in order to prevent the sound absorbing material of the extended sound absorbing unit from flowing out by the air current. Also good. Further, a plurality of sound absorbing (or breathable) porous cylinders having different diameters may be arranged concentrically, and a sound absorbing material may be arranged between adjacent cylinders.

  Intake devices (silencers) each composed of an extended sound absorption unit and a resonance unit can be used alone or in combination. That is, one or a plurality of intake devices may be provided along the gas flow path. When a plurality of intake devices are used, the resonance frequency of each intake device may have a different set frequency.

  In the present invention, an extended sound absorbing unit provided with a sound absorbing material around the gas flow path, a Helmholtz resonance unit for reducing sound from the sound absorbing unit, and a communication for communicating the extended sound absorbing unit and the resonance unit. Therefore, it is useful for reducing noise in a wide frequency range from the low frequency range to the high frequency range (noise in the gas flow path). In particular, since the generation of noise in the rebound frequency range in the resonance unit can be suppressed, noise in a low frequency range (for example, a frequency of 500 Hz or less) can be effectively removed and used as various intake devices (or silencers). . For example, it is useful for reducing noise in fluid supply / exhaust systems, for example, air blowing sound of blower units, airflow sound due to blowers and nozzles, intake / exhaust sound of internal combustion engines and gas generators, combustion noise due to burners, etc. is there. In particular, since the sound can be effectively silenced even if it is downsized, it can be installed in a small space and is suitable for installation in an air duct of an internal combustion engine of a vehicle.

FIG. 1 is a schematic longitudinal sectional view showing an example of an intake device of the present invention. FIG. 2 is a graph showing the silencing characteristics with and without the resonator and the silencing effect with the resonator. FIG. 3 is a graph showing the silencing characteristics of the sound absorbing duct and the silencing characteristics by the combination of the sound absorbing duct and the resonator. FIG. 4 is a graph showing the silencing characteristics of the sound absorbing duct and the silencing characteristics due to the combination of the sound absorbing duct and the large resonator. FIG. 5 is a graph showing the difference in the silencing effect between the conventional resonator and the resonator according to the present invention. FIG. 6 is a graph showing the difference in the silencing effect between the conventional sound absorbing duct and the sound absorbing duct according to the present invention. FIG. 7 is a graph showing the difference in the silencing effect between a sound absorbing device combining a conventional sound absorbing duct and a large resonator and the sound absorbing device of the present invention. FIG. 8 is a schematic cross-sectional view showing another example of the intake device of the present invention. FIG. 9 is a schematic sectional view showing still another example of the intake device of the present invention. FIG. 10 is a schematic perspective view showing the communication portion of FIG. FIG. 11 is a schematic sectional view showing another example of the intake device of the present invention. 12 is a schematic cross-sectional view showing the communication portion or the support portion of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11, 21, 31 ... Extended sound absorption unit 2, 12, 22, 32 ... Gas flow path 3, 13, 23, 33 ... Sound absorption material 4, 14, 24, 34 ... Resonance unit 5, 15, 25, 35 ... Neck part 6, 16, 26, 36 ... Bulkhead 7, 17, 27, 37 ... Communication part 9, 19, 29, 39 ... Expansion chamber

Claims (6)

  An extended sound absorbing unit including a sound absorbing material and an expansion chamber around the gas flow path, and a Helmholtz resonance unit located adjacent to the extended sound absorption unit and communicating with the gas flow path. An air intake apparatus, wherein a communication portion for communicating the unit and the Helmholtz resonance unit is formed.   The air intake device according to claim 1, further comprising a partition wall for partitioning the extended sound absorbing unit and the Helmholtz resonance unit, wherein the communication portion is formed in the partition wall.   The air intake device according to claim 2, wherein the communication portion is a hole or a porous air hole.   The intake device according to claim 2, wherein the communication portion is formed in a vertically lower portion of the partition wall.   The intake device according to claim 2, wherein the communication portion is formed at an intersection of the partition and the outer wall of the Helmholtz resonance unit or the extended sound absorption unit, and communicates with the outside.   An extended sound absorbing unit having a sound absorbing material and an expansion chamber around a gas flow path, and a Helmholtz resonance unit located adjacent to the extended sound absorption unit and communicating with the gas flow path, for reducing noise. A method for reducing noise by forming a communication portion for connecting the extended sound absorbing unit and the Helmholtz resonance unit between the extended sound absorption unit and the Helmholtz resonance unit.

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