Resonator and intake system

Abstract

To provide a resonator and an intake system that can adjust a length of a communication passage communicated to a muffler chamber without causing an increase in size of a device itself.SOLUTION: An intake system 20 includes: an intake pipe 12 for sucking air into an internal combustion engine; a muffler chamber 31 connected to the intake pipe 12 through a communication pipe 22 to muffle intake noise generated from the intake pipe 12; and an inner flow passage 32 formed by extending the communication pipe 22 inside the muffler chamber 31 and formed by being folded.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a resonator and an intake device.

Background Art

[0002] As a resonator, Patent Document 1 discloses a silencing device provided with a resonance silencing chamber 4, a tubular communication hole 5 that communicates the air hose 3 as an intake pipe and the resonance silencing chamber 4. The communication hole 5 is formed by a bellows 6, and since the length of the communication hole 5 can be changed according to the negative pressure in the air hose 3, the silencing frequency range can be changed.

[0003] Also, as a resonator, Patent Document 2 discloses a silencing device for an intake and exhaust system of an internal combustion engine, which has a tube 12 with one end opening to an intake pipe or an exhaust pipe of the internal combustion engine, and a volume chamber 13 connected to the other end of this tube 12. In the silencing device for the intake and exhaust system of the internal combustion engine, a fixed tube 22 and a moving tube 23 are housed in a case 21 having a rectangular box shape. The fixed tube 22 and the moving tube 23 each have a passage portion in a comb-like shape, and by combining them in a state of facing each other, a single continuous tube 12 is formed in a shape where it is bent in a U shape multiple times. The tube 12 is formed such that the length of the tube 12 can be made variable according to the frequency of the noise or the engine rotational speed.

[0004] Also, as a resonator, Patent Document 3 discloses a resonator in which a communication passage 13 that communicates an air flow path 5 and a silencing chamber 9 is formed in the silencing chamber 9.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

[0006] In the resonator disclosed in Patent Document 1 mentioned above, although the length of the communication hole 5 (bellows 6) can be adjusted, the need for installation space for the bellows 6 results in a problem of a large silencer. Similarly, in the resonator disclosed in Patent Document 2 mentioned above, although the length of the tube 12 can be adjusted, the need for installation space for the tube 12 results in a problem of a large silencer for the intake and exhaust system of the internal combustion engine. On the other hand, in the resonator disclosed in Patent Document 3 mentioned above, the communication passage 13 is housed within the silencer chamber 9, and since no dedicated space is required to install the communication passage 13, the problem of a large intake system with a resonator does not arise. However, it is required to arbitrarily set (extend) the length of the communication passage within a limited space (silencer chamber).

[0007] The present invention was made to solve the above-mentioned problems and aims to provide a resonator and intake device that allow adjustment of the length of the communication passage to the soundproofing chamber without increasing the size of the device itself. [Means for solving the problem]

[0008] To solve the above problems, the intake device according to the present invention is characterized by comprising: an intake pipe for drawing air into an internal combustion engine; a sound-dampening chamber connected to the intake pipe via a connecting pipe for muffling the intake noise generated in the intake pipe; and an internal flow path formed by extending the connecting pipe within the sound-dampening chamber and folding back.

[0009] According to the intake device of this invention, it is possible to provide an internal flow path within a sound-dampening chamber (limited space) whose flow path length can be set to any length, thereby providing an intake device that can adjust the length of the connecting pipe (communication passage) without increasing the size of the device itself.

[0010] Furthermore, in the intake device according to the present invention, it is preferable that the internal flow path comprises an inner flow path of an inner cylinder, one end of which is connected to the connecting pipe, and an outer flow path formed between a bottomed cylindrical outer cylinder and the inner cylinder, which is arranged to cover the opening at the other end of the inner cylinder. This makes it possible to form the internal flow path with a simple configuration (double pipe).

[0011] Furthermore, in the intake device according to the present invention, it is preferable that the internal flow path comprises a first internal flow path of a first cylindrical section, one end of which is connected to the connecting pipe; a second internal flow path of a second cylindrical section, which is arranged parallel to the first cylindrical section; and a third internal flow path of a folded pipe section, which is arranged to connect the first cylindrical section and the second cylindrical section. This makes it possible to form the internal flow path with a simple configuration (parallel pipes).

[0012] Furthermore, in the intake device according to the present invention, the sound-dampening chamber is an internal space formed by a first casing having a first wall with an opening connected to the connecting pipe, and a second casing assembled to the first casing, wherein the inner cylinder is a cylindrical member connected to the opening of the first casing and provided perpendicularly to the first wall, and the outer cylinder is a cylindrical member provided perpendicularly to the second wall of the second casing which is opposite the first wall of the first casing. This makes it possible to manufacture a sound-dampening chamber and thus an intake device having a double-pipe type internal flow path provided perpendicularly from the first wall by simply connecting the first casing and the second casing together.

[0013] Furthermore, in the intake device according to the present invention, the sound-dampening chamber is an internal space formed by a first casing having a first wall with an opening connected to the communication pipe, and a second casing assembled to the first casing, the inner cylinder includes a pair of first wall members connected to the opening of the first casing and provided along the first wall of the first casing, and a first ceiling member provided on the second casing side and covering the pair of first wall members, and the outer cylinder preferably includes a second wall member formed in a U shape on the first casing and arranged to surround the pair of first wall members, and a second ceiling member provided on the second casing side and covering the second wall members.According to this, it is possible to manufacture a sound-dampening chamber and thus an intake device having a double-pipe type internal flow path provided along the first wall by a simple method of connecting the first casing and the second casing together.

[0014] Furthermore, in the intake device according to the present invention, the sound-dampening chamber is an internal space formed by a first casing having a first wall with an opening connected to the connecting pipe, and a second casing assembled to the first casing, the first cylindrical section is a cylindrical member connected to the opening of the first casing and provided perpendicularly to the first wall, the second cylindrical section is provided in the first casing alongside the first cylindrical section, and the folded-back section is provided in the second wall of the second casing facing the first wall of the first casing. This makes it possible to manufacture a sound-dampening chamber and thus an intake device having a parallel pipe type internal flow path provided perpendicularly from the first wall by simply connecting the first casing and the second casing together.

[0015] Furthermore, in the intake device according to the present invention, the sound-dampening chamber is an internal space formed by a first casing having a first wall with an opening connected to the communication pipe, and a second casing assembled to the first casing; the first cylindrical section includes a pair of first wall members connected to the opening of the first casing and provided along the first wall of the first casing, and a first ceiling member provided on the second casing side and covering the pair of first wall members; the second cylindrical section includes either of the pair of first wall members, a second wall member positioned opposite to the one first wall member, and a second ceiling member provided on the second casing side and covering both the one first wall member and the second wall member; and preferably the folded-back section includes a third wall member formed in a U-shape on the first casing and arranged to connect the first cylindrical section and the second cylindrical section, and a third ceiling member provided on the second casing side and covering the third wall member. According to this, it becomes possible to manufacture a sound-dampening chamber and, consequently, an intake device having a parallel-tube type internal flow path along the first wall by simply connecting the first casing and the second casing together.

[0016] Furthermore, the resonator according to the present invention is characterized by comprising a sound-dampening chamber connected to a transport pipe that transports air via a connecting pipe, which dampens the sound generated in the transport pipe, and an internal flow path formed by extending the connecting pipe within the sound-dampening chamber and folding back. According to the resonator of this invention, it is possible to provide an internal flow path within a sound-dampening chamber (limited space) whose flow path length can be set to any length. Therefore, it is possible to provide a resonator that can adjust the length of the connecting pipe (communication passage) without increasing the size of the device itself.

[0017] Furthermore, in the resonator according to the present invention, it is preferable that the internal flow path comprises an inner flow path of an inner cylinder, one end of which is connected to the connecting pipe, and an outer flow path formed between a bottomed cylindrical outer cylinder and the inner cylinder, which is arranged to cover the opening at the other end of the inner cylinder. This makes it possible to form the internal flow path with a simple configuration (double pipe).

[0018] Also, in the resonator according to the present invention, it is preferable that the internal flow path includes a first internal flow path of a first cylindrical tube portion having one end connected to the communication pipe, a second internal flow path of a second cylindrical tube portion arranged side by side with the first cylindrical tube portion, and a third internal flow path of a folded tube portion arranged to communicate the first cylindrical tube portion and the second cylindrical tube portion. According to this, it becomes possible to form an internal flow path with a simple configuration (parallel pipes).

Advantages of the Invention

[0019] According to this invention, it becomes possible to provide a resonator and an intake device that can adjust the length of a communication path communicating with a soundproof chamber without causing an increase in the size of the device itself.

Brief Description of the Drawings

[0020] [Figure 1] It is a configuration diagram showing an embodiment (double-pipe vertical type) of an internal combustion engine 11 to which a resonator 30 and an intake device 20 according to the present invention are applied. [Figure 2] It is a plan view of the resonator 30 and the intake device 20 shown in FIG. 1. [Figure 3] It is a cross-sectional view showing the resonator 30 and the intake device 20 along the line 3-3 shown in FIG. 2. [Figure 4] It is a cross-sectional view showing a resonator 130 and an intake device 20 according to a modified example. [Figure 5] It is a diagram showing frequency characteristics indicating the effects of the resonator 130 according to Examples 1 to Examples 3 (Comparative Example 1 and Comparative Example 2). The vertical axis indicates the sound intensity, sound pressure level [dB], and the horizontal axis indicates the frequency [Hz]. [Figure 6] It is a plan view of a resonator 230 and an intake device 220 according to a first modified example (parallel-pipe vertical type). [Figure 7] It is a cross-sectional view showing the resonator 230 and the intake device 220 along the line 7-7 shown in FIG. 6. [Figure 8] It is a cross-sectional view showing a resonator 230 and an intake device 220 according to a modified example of a dividing portion. [Figure 9] This is a plan view of the resonator 430 and intake device 420 according to the second modified example (double-pipe horizontal type). [Figure 10] Figure 9 is a cross-sectional view showing the resonator 430 and intake device 420 along the line 10-10. [Figure 11] Figure 10 is a cross-sectional view showing the resonator 430 along line 11-11. [Figure 12] Figure 10 is a cross-sectional view showing the resonator 430 along line 12-12. [Figure 13] This is a plan view of the resonator 530 and intake device 520 according to the third modified example (parallel tube horizontal type). [Figure 14] Figure 13 is a cross-sectional view showing the resonator 530 and intake device 520 along line 14-14. [Figure 15] Figure 14 is a cross-sectional view showing the resonator 530 along the line 15-15. [Figure 16] Figure 14 is a cross-sectional view showing the resonator 530 along line 16-16. [Figure 17] Figure 14 is a cross-sectional view showing the resonator 530 along line 17-17. [Modes for carrying out the invention]

[0021] Hereinafter, an embodiment of the resonator and intake device according to the present invention will be described with reference to the drawings. However, the present invention is not limited to this embodiment and can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

[0022] As shown in Figure 1, the intake device 20 is installed in the intake pipe 12 provided in the intake system of the internal combustion engine 11. The intake pipe 12 connects the intake manifold 13 and the air cleaner 14 of the internal combustion engine 11, and is a pipe that supplies air that has passed through the air cleaner 14 to the internal combustion engine 11 via the intake manifold 13.

[0023] As shown in Figures 2 and 3, the intake device 20 is a device in which a resonator 30 is connected to an intake pipe section 21, which is a pipe constituting a part of the intake pipe 12. The intake device 20 comprises an intake pipe section 21, a connecting pipe 22, and a resonator 30. The intake pipe section 21 is a pipe member for drawing air into the internal combustion engine 11, and both ends of the intake pipe section 21 are connected to the intake pipe 12. The connecting pipe 22 connects the intake pipe section 21 and the silencer chamber 31 of the resonator 30. One end of the connecting pipe 22 is connected to the side of the intake pipe section 21, and the other end of the connecting pipe 22 is connected to one opening of the internal flow path 32. The intake device 20 is preferably made of synthetic resin. As synthetic resins, thermosetting resins such as phenolic resin and melamine resin, or thermoplastic resins such as polyethylene, polypropylene, acrylic resin, and polycarbonate can be used.

[0024] The resonator 30 is a device installed in the intake system (e.g., the intake pipe 12) to reduce noise (intake noise) generated in the intake system. The resonator 30 may also be installed in the exhaust system (e.g., the exhaust pipe) that discharges exhaust gas from the internal combustion engine 11, not just in the intake system. Furthermore, the intake pipe 12 and the exhaust pipe may also be referred to as transport pipes that carry gas (or air).

[0025] As shown in Figure 3, the resonator 30 includes a sound-dampening chamber 31 and an internal flow path 32. The sound-dampening chamber 31 is connected to the intake pipe 12 via a connecting pipe 22 and dampens the sound generated in the intake pipe 12. The internal flow path 32 is a flow path that extends the connecting pipe 22 within the sound-dampening chamber 31 and is formed by folding back.

[0026] The resonator 30 shown in Figure 3 is a so-called double-tube vertical type resonator. Note that, in addition to the double-tube vertical type, resonators also include the parallel-tube vertical type, the double-tube horizontal type, and the parallel-tube horizontal type, which will be described later. In this context, "vertical" indicates that the double-tube or parallel-tube (internal flow path) is installed perpendicular to the wall having the opening 41a1, while "horizontal" indicates that the double-tube or parallel-tube is installed parallel to the wall having the opening 41a1.

[0027] The resonator 30 has a first casing 41, a second casing 42, an inner cylinder 43, and an outer cylinder 44. The resonator 30 is preferably made of synthetic resin.

[0028] The first casing 41 has a bottom wall 41a, which is the first wall, and a side wall 41b that is provided perpendicularly from the periphery of the bottom wall 41a. In this embodiment, the bottom wall 41a is formed in a rectangular shape, and the side wall 41b is also formed in a rectangular shape when viewed from above (in other words, in a rectangular frame shape). However, the shapes of the bottom wall 41a and the side wall 41b are not limited to a rectangular shape, and may be circular or other polygonal shapes.

[0029] An opening 41a1 is formed in the bottom wall 41a, and the upper end (upper opening end) of the communication pipe 22 is connected to the opening 41a1. The lower end (lower opening end) of the inner cylinder 43 is also connected to the opening 41a1. The inner cylinder 43 is a cylindrical member provided perpendicular to the bottom wall 41a. In this embodiment, the inner cylinder 43 is formed in a cylindrical shape. However, the shape of the inner cylinder 43 is not limited to a cylindrical shape and may be a polygonal cylinder.

[0030] The second casing 42 has an upper wall 42a, which is a second wall, and a side wall 42b that is provided perpendicularly from the periphery of the upper wall 42a. In this embodiment, the upper wall 42a is formed in a rectangular shape, similar to the bottom wall 41a, and the side wall 42b is formed in a rectangular shape (rectangular frame shape) in plan view, similar to the side wall 41b.

[0031] The upper wall 42a is a wall positioned opposite the bottom wall 41a of the first casing 41, and the outer cylinder 44 is provided vertically on the upper wall 42a. The outer cylinder 44 is formed in a bottomed cylindrical shape and has an outer cylinder bottom portion 44a and an outer cylinder body portion 44b provided vertically on the periphery of the outer cylinder bottom portion 44a. The outer cylinder body portion 44b is formed in a cylindrical shape, similar to the inner cylinder 43, and the outer cylinder bottom portion 44a is formed in a circular shape. The outer cylinder bottom portion 44a and the outer cylinder body portion 44b are formed integrally. The outer cylinder bottom portion 44a forms a part of the upper wall 42a. The outer cylinder body portion 44b is a cylindrical member, similar to the inner cylinder 43, but is formed with a larger diameter than the inner cylinder 43 and is positioned outside the inner cylinder 43 so as to cover (surround) the inner cylinder 43. In this embodiment, the bottom portion 44a of the outer cylinder is formed as part of the upper wall 42a, but the invention is not limited to this, and it may be formed from a separate component from the upper wall 42a (as will be described later).

[0032] The opening end (lower end) of the side wall 42b is connected to the opening end (upper end) of the side wall 41b of the first casing 41, thereby assembling the first casing 41 and the second casing 42. As a result, an internal space is formed by the first casing 41 and the second casing 42. This internal space is the sound-absorbing chamber 31. The first casing 41 and the second casing 42 are connected by adhesive, vibration welding, claw fitting, etc.

[0033] In this resonator 30, the sound-dampening chamber 31 is located within an internal space partitioned by a first casing 41 and a second casing 42. The sound-dampening chamber 31 communicates with the intake pipe 12 via an internal flow path 32 and a connecting pipe 22. In other words, the sound-dampening chamber 31 can be described as the internal space other than the internal flow path 32.

[0034] In the resonator 30, the internal flow path 32 comprises an inner flow path 32a of an inner cylinder 43, one end (lower end) of which is connected to a communication pipe 22; an outer flow path 32b formed between the inner cylinder 43 and a bottomed cylindrical outer cylinder 44 positioned to cover the other end opening (upper end opening) of the inner cylinder 43; and a folded (bent) folded flow path 32c connecting the inner flow path 32a and the outer flow path 32b. The total length of the internal flow path 32 is the sum of the flow path length La of the inner flow path 32a, the flow path length Lb of the outer flow path 32b, and the flow path length Lc of the folded flow path 32c.

[0035] The inner channel 32a is a channel formed by the inner space of the inner cylinder 43. In the inner channel 32a, sound (sound waves) that flow into the inner channel 32a travels through the inner channel 32a either directly or while being reflected off the inner wall surface of the inner channel 32a (the inner wall surface of the inner cylinder 43) and flows out from the inner channel 32. At this time, it is thought that there are various paths for sound propagation, not a uniform one. Therefore, we assume that the average propagation path of these sounds is a line along the central axis of the inner channel 32a (inner cylinder 43), and we assume that the length of the average propagation path is the channel length La of the inner channel 32a. Thus, the channel length La of the inner channel 32a is the axial length of the inner cylinder 43.

[0036] The outer channel 32b is a channel formed by the space created between the outer cylinder body 44b and the inner cylinder 43. In the outer channel 32b, sound (sound waves) that flows into the outer channel 32b either travels through the outer channel 32b as is or reflects off the inner wall surface of the outer channel 32b (the outer wall surface of the inner cylinder 43 and the inner wall surface of the outer cylinder body 44b) and flows out of the outer channel 32b into the sound-absorbing chamber 31. At this time, it is thought that there are various paths for sound propagation, not a uniform path, so the average propagation path of these sounds is assumed to be the center line of the outer channel 32b (the radial midpoint between the inner cylinder 43 and the outer cylinder body 44b). Therefore, the channel length Lb of the outer channel 32b can be set to the axial length of the average propagation path, and the channel length Lb is the length of the part where the outer cylinder body 44b and the inner cylinder 43 overlap in the axial direction.

[0037] The reverse channel 32c is a channel formed by the portion of the outer cylinder 44 that does not overlap with the inner cylinder 43 in the axial direction. In other words, the reverse channel 32c is a channel formed by the inner portion of the outer cylinder 44 located above the upper end of the inner cylinder 43 (towards the bottom of the outer cylinder 44). In the reverse channel 32c, sound that has propagated through the inner channel 32a enters the outer channel 32b while reflecting off the inner wall surface of the reverse channel 32c. At this time, it is thought that there are various sound propagation paths rather than a uniform one, so the average propagation path of these sounds is assumed to be the center line of the reverse channel 32c. For example, this center line can be a curve (e.g., semicircular, semielliptical) connecting the average propagation path of the inner channel 32a and the average path of the outer channel 32b. Therefore, the channel length Lc of the reverse channel 32c can be set to the length of this curve.

[0038] Furthermore, it is preferable that the cross-sectional area of ​​the inner channel 32a and the cross-sectional area of ​​the outer channel 32b be set to be approximately the same, and that the cross-sectional area of ​​the channel be set to be approximately the same along the entire length of the inner channel 32. As shown in Equation 1 described later, the silencing frequency f0 is set according to the length and cross-sectional area of ​​the connecting pipe, and if the cross-sectional area of ​​the connecting pipe differs from place to place, there will be multiple silencing frequencies f0, which will complicate the frequency characteristics, so it is preferable that the cross-sectional areas of the channel be set to be approximately the same in order to simplify the frequency characteristics.

[0039] Furthermore, although sound (sound waves) are longitudinal waves (compression waves), in this specification they are treated as transverse waves and are assumed to propagate along the average propagation path described above. Also, the intake device 20 described above may be a single component in which the intake pipe section 21, the connecting pipe 22, and the resonator 30 are integrated, or the intake pipe section 21, the connecting pipe 22, and the resonator 30 may be formed as separate components and assembled from these separate components.

[0040] (Molding method (process)) The first casing 41 and the second casing 42 of the resonator 30 described above are preferably injection molded using a molding die equipped with a cavity mold (concave mold) and a core mold (convex mold). Since neither the first casing 41 nor the second casing 42 has an undercut shape, they can be removed from the molding die simply by opening and closing the parting surface of the cavity mold and core mold, and can be formed relatively easily. Undercut shapes require special mold structures such as slide cores or inclined pins, and cannot be removed simply by opening and closing the parting surface. Examples of undercut shapes include lateral holes, protrusions, and recesses.

[0041] The first casing 41 and the second casing 42 are combined to connect the open end (lower end) of the side wall 42b of the second casing 42 to the open end (upper end) of the side wall 41b of the first casing 41. At this time, a double-tube structure is formed in which the inner cylinder 43 is coaxially arranged within the outer cylinder body 44b, and a resonator 30 is formed in which this double-tube structure is provided perpendicularly to the bottom wall 41a, which is the first wall of the first casing 41.

[0042] Furthermore, the resonator 30 is connected to the intake pipe section 21 via the connecting pipe 22 using adhesive or the like, thereby forming the intake device 20.

[0043] Furthermore, the first casing 41, the connecting pipe 22, and the intake pipe section 21 may be molded integrally. In this case, the first casing 41 with the intake pipe section will have an undercut shape, which will make the molding die relatively complex, but it will be possible to make the first casing 41, the connecting pipe 22, and the intake pipe section 21 into a single component, thereby reducing the number of parts.

[0044] In the intake device 20 (double-pipe vertical type) according to this embodiment, the silencer chamber 31 is an internal space formed by a first casing 41 having a first wall (bottom wall 41a) with an opening 41a1 connected to the communication pipe 22, and a second casing 42 assembled to the first casing 41. Preferably, the inner cylinder 43 is a cylindrical member connected to the opening 41a1 of the first casing 41 and provided perpendicular to the bottom wall 41a, and the outer cylinder 44 is a cylindrical member provided perpendicular to the second wall (upper wall 42a) of the second casing 42 facing the bottom wall 41a of the first casing 41. According to this, it is possible to manufacture the silencer chamber 31 and thus the intake device 20 having a double-pipe type internal flow path provided perpendicularly from the bottom wall 41a by a simple method of connecting the first casing 41 and the second casing 42 together.

[0045] (Modified version: annular recess at the bottom of the outer cylinder) Furthermore, in the resonator 30 described above, the inner wall surface of the outer cylinder bottom 44a of the outer cylinder 44 is formed to be a flat surface (the outer cylinder bottom 44a is formed from a part of the upper wall 42a), but the inner wall surface of the outer cylinder bottom may be formed to be a curved surface that increases the sound reflection efficiency. In this case, in the resonator 130, as shown in Figure 4, the outer cylinder 144 is provided vertically on the upper wall 42a of the second casing 42. The outer cylinder 144 is formed in the shape of a bottomed cylinder and has an outer cylinder bottom 144a and an outer cylinder body 144b provided vertically on the periphery of the outer cylinder bottom 144a. The outer cylinder body 144b is formed in the same cylindrical shape as the outer cylinder body 44b, is formed to be larger in diameter than the inner cylinder 43, and is positioned outside the inner cylinder 43 so as to cover (surround) the inner cylinder 43. The outer cylinder bottom 144a is formed in the shape of a disc. The outer cylinder bottom portion 144a and the outer cylinder body portion 144b are formed integrally.

[0046] The internal flow path 132 comprises an inner flow path 132a of an inner cylinder 43, one end (lower end) of which is connected to a connecting pipe 22; an outer flow path 132b formed between the inner cylinder 43 and a bottomed cylindrical outer cylinder 144 positioned to cover the other end opening (upper end opening) of the inner cylinder 43; and a folded-back (bent) folded-back flow path 132c (similar to the folded-back flow path 32c described above) connecting the inner flow path 132a and the outer flow path 132b.

[0047] An annular recess 144a1 is formed on the lower surface (inner bottom surface) of the bottom 144a of the outer cylinder, and the cross-section of the recess 144a1 is formed in a curved shape in which the curvature decreases as you move outward from the center of the bottom 144a of the outer cylinder. Preferably, the inner wall surface of the recess 144a1 is formed in a shape that increases the reflection efficiency so that sound that has traveled through the inner cylinder 43 (inner flow path 132a) travels as far as possible into the outer flow path 132b (the space formed between the outer cylinder body 144b and the inner cylinder 43). However, the cross-section of the recess 144a1 is not limited to a curved shape in which the curvature decreases as you move outward from the center of the bottom 144a of the outer cylinder, but may also be formed in a semicircular shape (constant curvature), a curved shape in which the curvature increases as you move outward from the center of the bottom 144a of the outer cylinder, or it may be formed in a polygonal shape instead of a curved shape.

[0048] The upper surface of the bottom portion 144a of the outer cylinder is connected to the inner wall surface of the upper wall 42a. In this case, it is preferable that the bottom portion 144a of the outer cylinder is molded integrally with the upper wall 42 (second casing 42). Alternatively, the second casing 42 and the outer cylinder 144 may be formed as separate components and then connected by adhesive or welding.

[0049] Furthermore, in this modified example, not only are the cross-sectional areas of the inner channel 132a and the outer channel 132b set to be approximately the same, but the cross-sectional area of ​​the return channel 132c is also set to be approximately the same, making it possible to set the cross-sectional area of ​​the channel to be approximately the same along the entire length of the internal channel 132. Therefore, it is possible to suppress and simplify changes in the sound dampening frequency f0.

[0050] (Examples) Next, an embodiment of the resonator 30 to which the present invention is applied will be described. Generally, in the resonator 30, the silencer frequency (specific frequency) f0 of the intake sound (generated sound) is reduced based on the principle of the "Helmholtz resonator". The silencer frequency f0 is shown in the following equation 1. (Math 1) f0 = (c / 2π) × √(S / (V × L)) Here, c is the speed of sound, S is the cross-sectional area of ​​the internal flow path, V is the volume of the silencer (resonance chamber), and L is the length of the internal flow path (connecting pipe). The connecting pipe is the pipe that connects the resonance chamber and the intake pipe. In other words, the pressure inside the soundproofing chamber vibrates at a specific frequency determined by the volume of the soundproofing chamber and the diameter and length of the internal flow path (connecting pipe). This vibration is attenuated by reflected waves within the soundproofing chamber, and the sound energy is reduced by friction as the flow (sound waves) travels through the internal flow path.

[0051] Furthermore, if the space and location for mounting the resonator 30 are limited, the volume of the sound-dampening chamber (resonance chamber) cannot be increased or decreased. Therefore, in order to change a specific frequency, it is necessary to change the length and diameter of the connecting pipe. In the present invention, by extending the connecting pipe into the resonance chamber, it becomes possible to change a specific frequency. In other words, even if the installation space for the resonator 30 is limited, it becomes possible to change the length of the connecting pipe within the resonance chamber, thereby changing a specific frequency.

[0052] As is clear from the above equation 1, the longer the connecting pipe, the smaller the specific frequency f0 becomes. Furthermore, the smaller the cross-sectional area of ​​the connecting pipe, the smaller the specific frequency f0 becomes.

[0053] Figure 5 shows the frequency characteristics of Examples 1 to 3 and Comparative Examples 1 and 2. The frequency characteristics may be measured experimentally or obtained by simulation. The resonator 130 of Example 1 is a so-called double-tube vertical type, as shown in Figure 4, and the inner wall surface of the bottom of the outer cylinder 144a is formed as a curved surface that increases the sound reflection efficiency. Furthermore, the outer cylinder body 144b and the inner cylinder 43 overlap by a predetermined length (for example, 21 mm) in the axial direction.

[0054] The resonator 130 of Example 2 has a shorter overlap amount than the resonator 130 of Example 1 (for example, 11 mm), and is otherwise the same structure as the resonator 130 of Example 1. In other words, in Example 2, the total length of the internal flow path 132 is shorter than in Example 1. The resonator 130 of Example 3 has an overlap amount of 0 mm, and is otherwise the same structure as the resonator 130 of Example 1. In other words, in Example 3, the total length of the internal flow path 132 is the sum of the inner flow path 132a and the return flow path 132c.

[0055] The resonator of Comparative Example 1 has a structure in which the outer cylinder 144 is removed from the resonator 130 of Example 1, and it has only an inner cylinder 43. The resonator of Comparative Example 2 has a shorter inner cylinder 43 than the resonator of Comparative Example 1.

[0056] Thus, the length of the internal flow path decreases in the order of Examples 1 to 3, Comparative Example 1, and Comparative Example 2, and the sound silencing frequency also decreases in this order. In other words, it is possible to change the sound silencing frequency by changing the length of the internal flow path without changing the size (external dimensions, volume) of the sound silencing chamber 131.

[0057] (First variation: Parallel tube vertical type resonator) Furthermore, a so-called parallel-tube vertical type resonator 230 (sound absorption device 220) will be described. As shown in Figures 6 and 7, this resonator 230 has two folded and parallel cylindrical sections, and one of these cylindrical sections is connected perpendicularly to an opening 41a1 in the bottom wall 41a of the first casing 241, comprising a parallel cylindrical section 246.

[0058] The resonator 230 shown in Figure 7 is a so-called parallel-tube vertical type resonator. The resonator 230 has a first casing 241, a second casing 242, and a parallel tube section 246. The resonator 230 is preferably made of synthetic resin.

[0059] The first casing 241, like the first casing 41 described above, has a bottom wall 41a which is the first wall, and a side wall 41b which is provided perpendicularly from the periphery of the bottom wall 41a. An opening 41a1 is formed in the bottom wall 41a, and the upper end (upper opening end) of the communication pipe 22 is connected to the opening 41a1. The second casing 242, like the second casing 42 described above, has an upper wall 42a which is the second wall, and a side wall 42b which is provided perpendicularly from the periphery of the upper wall 42a.

[0060] The parallel pipe section 246 comprises a first cylindrical pipe section 243, a second cylindrical pipe section 244, and a folded pipe section 245. The parallel pipe section 246 is formed such that the first cylindrical pipe section 243, the second cylindrical pipe section 244, and the folded pipe section 245 are connected to form a roughly J-shape (or U-shape).

[0061] The first cylindrical section 243 is a cylindrical member connected to the opening 41a1 of the first casing 241 and provided perpendicular to the bottom wall 41a. One end (lower end) of the first cylindrical section 243 is connected to the opening 41a1 of the first casing 241. The other end (upper end) of the first cylindrical section 243 is connected to one end (lower end) of the folded-back section 245. In this first modified example, the first cylindrical section 243 is formed in a cylindrical shape with a D-shaped cross-section. However, the shape of the first cylindrical section 243 is not limited to a D-shaped cross-section; it may also be cylindrical or polygonal.

[0062] The second cylindrical section 244 is arranged alongside the first cylindrical section 243. The other end (upper end) of the second cylindrical section 244 is connected to one end (lower end) of the folded pipe section 245. One end (lower end) of the second cylindrical section opens into the sound-dampening chamber 231. In this first modified example, the second cylindrical section 244 is formed in a cylindrical shape with a D-shaped cross-section, similar to the first cylindrical section 243. The cross-sectional area of ​​the second cylindrical section 244 (second internal flow path 232b) is set to be the same as the cross-sectional area of ​​the first cylindrical section 243 (first internal flow path 232a).

[0063] The folded pipe section 245 connects the first cylindrical pipe section 243 and the second cylindrical pipe section 244 by folding them back. The folded pipe section 245 is formed in the same way as the outer cylinder 44 described above, and has a folded bottom portion 245a and a folded cylindrical section 245b provided perpendicularly to the periphery of the folded bottom portion 245a. The folded cylindrical section 245b is formed in the shape of a cylindrical section with a substantially elliptical cross-section, which is the shape formed by combining the first cylindrical pipe section 243 and the second cylindrical pipe section 244, and the folded bottom portion 245a is formed in a substantially elliptical shape. The folded bottom portion 245a and the folded cylindrical section 245b are formed integrally.

[0064] The other end (upper end) of the first cylindrical section 243 and the other end (upper end) of the second cylindrical section are connected to one end (lower end) of the folded-back pipe section 245. The upper end of the folded-back pipe section 245 is connected to the upper wall 42a of the second casing 242. It can be said that a part of the upper wall 42a forms the folded-back bottom section 245a. In this way, the parallel pipe section 246 is provided perpendicular to the upper wall 42a of the second casing 242, which is a wall positioned opposite the bottom wall 41a of the first casing 241. In this first modified example, the folded-back bottom section 245a is formed as part of the upper wall 42a, but it is not limited to this, and may be formed from a separate member from the upper wall 42a.

[0065] In this resonator 230, the sound-dampening chamber 231 is located within an internal space partitioned by a first casing 241 and a second casing 242, similar to the sound-dampening chamber 31 described above. The sound-dampening chamber 231 communicates with the intake pipe 12 via an internal flow path 232 and a connecting pipe 22. In other words, the sound-dampening chamber 231 can be described as the internal space other than the internal flow path 232.

[0066] In the resonator 230, the internal flow path 232 comprises a first internal flow path 232a of a first cylindrical section 243, one end (lower end) of which is connected to a connecting pipe 22; a second internal flow path 232b of a second cylindrical section 244, which is arranged alongside the first cylindrical section 243; and a third internal flow path 232c of a folded pipe section 245 that connects the first cylindrical section 243 and the second cylindrical section 244 by folding back. The total length of the internal flow path 232 is the sum of the flow path length La of the first internal flow path 232a, the flow path length Lb of the second internal flow path 232b, and the flow path length Lc of the third internal flow path 232c.

[0067] The first internal channel 232a is a channel formed by the inner space of the first cylindrical section 243. In the first internal channel 232a, sound travels in the same way as in the internal channel 32a described above, so the channel length La of the first internal channel 232a is the axial length of the first cylindrical section 243. The second internal channel 232b is a channel formed by the inner space of the second cylindrical section 244. In the second internal channel 232b, sound travels in the same way as in the first internal channel 232a described above, so the channel length Lb of the second internal channel 232b is the axial length of the second cylindrical section 244.

[0068] The third internal channel 232c is a channel formed by the internal space of the folded pipe section 245. In the third internal channel 232c, similar to the folded channel 32c described above, sound that has propagated through the first internal channel 232a enters the second internal channel 232b while reflecting off the inner wall surface of the third internal channel 232c. For example, the centerline of the third internal channel 232c can be a curve (e.g., semicircular or semielliptical) connecting the average propagation path of the first internal channel 232a and the average path of the second internal channel 232b. Therefore, the channel length Lc of the third internal channel 232c can be set to the length of this curve.

[0069] Furthermore, the parallel pipe section 246 has a first divided section 246a and a second divided section 246b.

[0070] The first division portion 246a is the portion of the parallel pipe section 246 that is located on the first casing 241 side. The first division portion 246a can be described as the portion of the parallel pipe section 246 that is integrally formed with the first casing 241. The second division portion 246b is the portion of the parallel pipe section 246 that is located on the second casing 242 side. The second division portion 246b can be described as the portion of the parallel pipe section 246 that is integrally formed with the second casing 242.

[0071] In this first modified example, the first divided portion 246a has the lower part of the first cylindrical portion 243. The lower end of the first divided portion 246a is integrally formed with the bottom wall portion 41a of the first casing 241. The height of the first divided portion 246a is set to be the same as the height of the first casing 241.

[0072] The second divided section 246b has the upper part of the first cylindrical section 243, the second cylindrical section 244, and the folded-back section 245. The upper part of the first cylindrical section 243, the second cylindrical section 244, and the folded-back section 245 are integrally formed. The upper end of the folded-back section 245 is integrally formed with the upper wall 42a of the second casing 242. The height of the second divided section 246b is set to be the same as the height of the second casing 242.

[0073] The open end (upper end) of the side wall 41b of the first casing 241 is connected to the open end (lower end) of the side wall 42b of the second casing 242 by adhesive, vibration welding, etc., and the upper end of the first divided section 246a is connected to the lower end of the second divided section 246b by adhesive, vibration welding, claw fitting, etc.

[0074] (Modified version of the divided section) In addition, although the second divided section 246b described above has the upper part of the first cylindrical section 243, the second cylindrical section 244, and the folded-over section 245, as shown in Figure 8, the second divided section 346b may have only the folded-over section 345. In this case, the first divided section 346a has the first cylindrical section 343 and the second cylindrical section 344.

[0075] Alternatively, the first dividing section described above may be omitted, and only the second dividing section described above may be provided. In this case, the second dividing section has the first cylindrical section 243, the second cylindrical section 244, and the folded-over section 245 described above. Alternatively, the second dividing section described above may be omitted, and only the first dividing section described above may be provided. In this case, the first dividing section has the first cylindrical section 243, the second cylindrical section 244, and the folded-over section 245 described above.

[0076] In the intake device 220 (parallel pipe vertical type) according to this first modified example, the silencer chamber 231 is an internal space formed by a first casing 241 having a first wall (bottom wall 41a) with an opening 41a1 connected to the communication pipe 22, and a second casing 242 assembled to the first casing 241. The first cylindrical pipe section 243 is a cylindrical member connected to the opening 41a1 of the first casing 241 and provided perpendicular to the bottom wall 41a. The second cylindrical pipe section 244 is provided in the first casing 241 alongside the first cylindrical pipe section 243, and the folded pipe section 245 is preferably provided on the second wall (upper wall 42a) of the second casing 242 facing the bottom wall 41a of the first casing 241. According to this, it is possible to manufacture a sound-dampening chamber 231 and, consequently, an intake device 220 having a parallel-tube type internal flow path vertically installed from the bottom wall 41a by simply connecting the first casing 241 and the second casing 242 together.

[0077] (Second variation: Double-tube horizontal type resonator) Furthermore, a so-called double-tube horizontal type resonator 430 (sound absorption device 420) will be described. As shown in Figures 9 and 10, this resonator 430 has an inner cylinder 443 and an outer cylinder 444, and the inner cylinder is provided with a double-tube section 446 that is horizontally connected to an opening 41a1 in the bottom wall 41a of the first casing 441.

[0078] The resonator 430 shown in Figure 10 has a first casing 441, a second casing 442, and a double-tube section 446. The resonator 430 is preferably made of synthetic resin.

[0079] The first casing 441, like the first casing 41 described above, has a bottom wall 41a which is a first wall, and a side wall 41b which is provided perpendicularly from the periphery of the bottom wall 41a. An opening 41a1 is formed in the bottom wall 41a, and the upper end (upper opening end) of the communication pipe 22 is connected to the opening 41a1.

[0080] As shown in Figures 9 and 10, the second casing 442 is a casing that airtightly covers the opening of the first casing 441, and includes a first ceiling member 443d (described later) and a second ceiling member 444d (described later), and has an upper wall 442a formed in a T-shape in plan view, and a pair of rectangular parallelepiped protrusions 442b and 442c provided on both sides of the upper wall 442a, projecting upward. The spaces within each of the protrusions 442b and 442c form a sound-absorbing chamber 431.

[0081] The peripheral edge (lower end) of the second casing 442 is connected to the open end (upper end) of the side wall 41b of the first casing 441, thereby assembling the first casing 441 and the second casing 442. As a result, an internal space is formed by the first casing 441 and the second casing 442. This internal space is the sound-absorbing chamber 431. The first casing 441 and the second casing 442 are connected by adhesive, vibration welding, claw fitting, etc.

[0082] As shown in Figures 9 and 10, the inner cylinder 443 is a cylindrical member connected to the opening 41a1 of the first casing 441 and provided horizontally (in the front-rear direction) along the bottom wall 41a. The inner cylinder 443 is formed in a bottomed cylindrical shape, with one end (front end) of the inner cylinder 443 connected to the opening 41a1 of the first casing 441. The other end (rear end) of the inner cylinder 443 is inserted into the outer cylinder 444. In this second modified example, as shown in Figures 11 and 12, the inner cylinder 443 is formed in a rectangular cross-section (square cylindrical shape). However, the shape of the inner cylinder 443 is not limited to a rectangular cross-section; it may also be circular or polygonal in cross-section.

[0083] The inner cylinder 443 is formed by a pair of first wall members 443a and 443b, an inner cylinder bottom 443c (see Figures 9 and 10), a part of the bottom wall 41a, and a first ceiling member 443d. The pair of first wall members 443a and 443b are wall members that are perpendicular to each other and provided along the bottom wall 41a of the first casing 441. The inner cylinder bottom 443c is perpendicular to the bottom wall 41a of the first casing 441 and connects one end (front end) of each of the pair of first wall members 443a and 443b, forming the bottom of the inner cylinder 443. In this second modified example, the inner cylinder bottom 443c is formed in a semi-circular cross-section, but is not limited to this and may be formed in a rectangular shape.

[0084] The first ceiling member 443d is a ceiling member to which the upper ends of a pair of first wall members 443a and 443b are connected, and is provided on the second casing 442 side, covering the pair of first wall members 443a and 443b. In this second modified example, it can be said that a part of the upper wall 442a of the second casing 442 forms the first ceiling member 443d.

[0085] As shown in Figures 9 and 10, the outer cylinder 444 is formed in a bottomed cylindrical shape and has an outer cylinder bottom portion 444a and an outer cylinder body portion 444b provided perpendicularly to the periphery of the outer cylinder bottom portion 444a. As shown in Figures 11 and 12, the outer cylinder body portion 444b is formed in a rectangular cross-section, similar to the inner cylinder 443, and the outer cylinder bottom portion 444a is formed in a rectangular shape. The outer cylinder bottom portion 444a and the outer cylinder body portion 444b are formed integrally. The outer cylinder bottom portion 444a forms a part of the side wall 41b of the first casing 441. The outer cylinder body portion 444b is a cylindrical member, similar to the inner cylinder 443, and is formed to be larger than the inner cylinder 443, and is positioned outside the inner cylinder 443 so as to cover (surround) the inner cylinder 443. In this embodiment, the bottom portion 444a of the outer cylinder is formed as part of the side wall 41b, but the invention is not limited to this, and may be formed from a separate component from the side wall 41b.

[0086] Furthermore, as shown in Figure 9, the outer cylinder 444 is formed by a second wall member 444c which is formed in a U shape on the first casing 441 and arranged to surround a pair of first wall members 443a and 443b, a second ceiling member 444d which is provided on the second casing 442 side and covers the second wall member 444c, and a part of the bottom wall 41a of the first casing 441.

[0087] The second wall member 444c is a wall member provided perpendicularly from the bottom wall 41a of the first casing 441. The second wall member 444c comprises a wall member 444c1 arranged parallel to the outside of the first wall member 443a, a wall member 444c2 arranged parallel to the outside of the first wall member 443b, and a wall member 444c3 which is part of the side wall 41b and connects wall member 444c1 and wall member 444c2.

[0088] The second ceiling member 444d is a ceiling member to which the upper end of the second wall member 444c is connected, and is provided on the second casing 442 side, covering the second wall member 444c. In this second modified example, it can be said that a part of the upper wall 442a of the second casing 442 forms the second ceiling member 444d. Furthermore, the second ceiling member 444d can also cover the open end sides of the pair of first wall members 443a and 443b.

[0089] The bottom portion 444a of the outer cylinder is wall member 444c3 of the second wall member 444c. The outer cylinder body portion 444b is a cylindrical portion formed from wall member 444c1 of the second wall member 444c, wall member 444c2 of the second wall member 444c, the second ceiling member 444d of the second casing 442, and a part of the bottom wall 41a of the first casing 441.

[0090] In this resonator 30, the sound-dampening chamber 431 is located within an internal space partitioned by a first casing 441 and a second casing 442. The sound-dampening chamber 431 communicates with the intake pipe 12 via an internal flow path 432 and a connecting pipe 22. In other words, the sound-dampening chamber 431 can be described as the internal space other than the internal flow path 432.

[0091] In the resonator 30, as shown in Figure 9, the internal flow path 432 comprises an inner flow path 432a of an inner cylinder 443, one end (lower end) of which is connected to a communication pipe 22; an outer flow path 432b formed between the inner cylinder 443 and a bottomed cylindrical outer cylinder 444, which is positioned to cover the other end opening (upper end opening) of the inner cylinder 443; and a folded (bent) folded flow path 432c connecting the inner flow path 432a and the outer flow path 432b. The total length of the internal flow path 432 is the sum of the flow path length La of the inner flow path 432a, the flow path length Lb of the outer flow path 432b, and the flow path length Lc of the folded flow path 432c.

[0092] The inner channel 432a is a channel formed by the inner space of the inner cylinder 443. Therefore, similar to the inner channel 32a described above, the channel length La of the inner channel 432a is the axial length of the inner cylinder 443. The outer channel 432b is a channel formed by the space formed between the outer cylinder body 444b and the inner cylinder 443. Therefore, similar to the outer channel 32b described above, the channel length Lb of the outer channel 432b can be set to the axial length of the average propagation path, and the channel length Lb is the length of the portion where the outer cylinder body 444b and the inner cylinder 443 overlap in the axial direction. The reverse channel 432c is a channel formed by the portion of the outer cylinder 444 that does not overlap with the inner cylinder 443 in the axial direction. Therefore, similar to the reverse channel 32c described above, the channel length Lc of the reverse channel 432c can be set to the length of the centerline of the reverse channel 432c.

[0093] In the intake device 420 according to this second modified example, the silencer chamber 431 is an internal space formed by a first casing 441 having a first wall (bottom wall 41a) with an opening 41a1 connected to the communication pipe 22, and a second casing 442 assembled to the first casing 441, and the inner cylinder 443 is a pair of first wall members connected to the opening 41a1 of the first casing 441 and provided along the bottom wall 41a of the first casing 441. Preferably, the outer cylinder 444 includes 443a, 443b and a first ceiling member 443d provided on the second casing 442 side and covering a pair of first wall members 443a, 443b, and the outer cylinder 444 includes a second wall member 444c formed in a U shape on the first casing 441 and arranged to surround a pair of first wall members 443a, 443b, and a second ceiling member 444d provided on the second casing 442 side and covering the second wall member 444c. According to this, it is possible to manufacture a sound-absorbing chamber 431 and thus an intake device 420 having a double-pipe type internal flow path provided horizontally along the bottom wall 41a by simply joining the first casing 441 and the second casing 442 together.

[0094] (Third variation: Parallel tube horizontal type resonator) Next, a so-called parallel-tube horizontal type resonator 530 (sound absorption device 520) will be described. As shown in Figures 13 and 14, this resonator 530 has two folded and parallel cylindrical sections, and one of these cylindrical sections is connected to an opening 41a1 in the bottom wall 41a of the first casing 541, forming a parallel cylindrical section 546.

[0095] The resonator 530 shown in Figure 13 is a so-called parallel tube horizontal type resonator. The resonator 530 has a first casing 541, a second casing 542, and a parallel tube section 546. The resonator 530 is preferably made of synthetic resin.

[0096] As shown in Figure 14, the first casing 541, like the first casing 41 described above, has a bottom wall 41a which is the first wall, and a side wall 41b which is provided vertically from the periphery of the bottom wall 41a. An opening 41a1 is formed in the bottom wall 41a, and the upper end (upper opening end) of the communication pipe 22 is connected to the opening 41a1.

[0097] As shown in Figures 13 and 14, the second casing 542 is a casing that airtightly covers the opening of the first casing 541, and includes a first ceiling member 443d (described later) and a second ceiling member 444d (described later), and an upper wall 542a formed in an L-shape in plan view, and a rectangular parallelepiped-shaped protrusion 542b provided on the upper wall 542a that protrudes upward. The space within each protrusion 542b forms a sound-absorbing chamber 531.

[0098] The peripheral edge (lower end) of the second casing 542 is connected to the open end (upper end) of the side wall 41b of the first casing 541, thereby assembling the first casing 541 and the second casing 542. As a result, an internal space is formed by the first casing 541 and the second casing 542. This internal space is the sound-absorbing chamber 531. The first casing 541 and the second casing 542 are connected by adhesive, vibration welding, claw fitting, etc.

[0099] The parallel pipe section 546 comprises a first cylindrical pipe section 543, a second cylindrical pipe section 544, and a folded pipe section 545. The parallel pipe section 546 is formed such that the first cylindrical pipe section 543, the second cylindrical pipe section 544, and the folded pipe section 545 are connected to form a roughly J-shape (or U-shape).

[0100] As shown in Figures 13 and 14, the first cylindrical section 543 is a cylindrical member connected to the opening 41a1 of the first casing 541 and provided horizontally (in the front-rear direction) along the bottom wall 41a. One end (front end) of the first cylindrical section 543 is connected to the opening 41a1 of the first casing 541. The other end (rear end) of the first cylindrical section 543 is connected to one end (front end) of the folded-back section 545. In this third modified example, the first cylindrical section 543 is formed in a rectangular (square-shaped) form. However, the shape of the first cylindrical section 543 is not limited to a rectangular cross-section; it may also be circular or polygonal in cross-section.

[0101] The second cylindrical section 544 is arranged alongside the first cylindrical section 543. The other end (rear end) of the second cylindrical section 544 is connected to one end (front end) of the folded pipe section 545. One end (front end) of the second cylindrical section 544 opens into the sound-dampening chamber 531. In this third modified example, the second cylindrical section 544 is formed in a cylindrical shape with a rectangular cross-section, similar to the first cylindrical section 543. The cross-sectional area of ​​the second cylindrical section 544 (second internal flow path 532b) is set to be the same as the cross-sectional area of ​​the first cylindrical section 543 (first internal flow path 532a).

[0102] The folded pipe section 545 connects the first cylindrical pipe section 543 and the second cylindrical pipe section 544 by folding them back. The folded pipe section 545 is formed in the same way as the outer cylinder 44 described above, and has a folded bottom portion 545a and a folded cylindrical section 545b provided perpendicularly to the periphery of the folded bottom portion 545a. The folded cylindrical section 545b is formed in the shape of a rectangular cross-section, which is the shape formed by combining the first cylindrical pipe section 543 and the second cylindrical pipe section 544, and the folded bottom portion 545a is formed in a rectangular shape. The folded bottom portion 545a and the folded cylindrical section 545b are formed integrally.

[0103] The other end (rear end) of the first cylindrical section 543 and the other end (rear end) of the second cylindrical section 544 are connected to one end (front end) of the folded-back pipe section 545. The rear end of the folded-back pipe section 545 is connected to the side wall 41b of the first casing 541. It can be said that a part of the side wall 41b forms the folded-back bottom section 545a. In this way, the parallel pipe section 546 is provided horizontally along the bottom wall 41a of the first casing 541. In this third modified example, the folded-back bottom section 545a is formed as part of the side wall 41b, but it is not limited to this, and may be formed from a separate member from the side wall 41b.

[0104] Furthermore, as shown in Figure 16, the first cylindrical section 543 is formed by a pair of first wall members 543a and 543b, an inner cylindrical bottom 543c (see Figures 13 and 14), a part of the bottom wall 41a, and a first ceiling member 543d. The pair of first wall members 543a and 543b are wall members that are perpendicular to each other and provided along the bottom wall 41a of the first casing 541. As shown in Figure 13, the inner cylindrical bottom 543c is perpendicular to the bottom wall 41a of the first casing 541, connecting one end (front end) of each of the pair of first wall members 543a and 543b, and forming the bottom of the first cylindrical section 543. In this third modified example, the inner cylindrical bottom 543c is formed in a semi-circular cross-section, but is not limited to this, and may be formed in a rectangular cross-section.

[0105] The first ceiling member 543d is a ceiling member to which the upper ends of a pair of first wall members 543a and 543b are connected, and is provided on the second casing 542 side, covering the pair of first wall members 543a and 543b. In this third modified example, it can be said that a part of the upper wall 542a of the second casing 542 forms the first ceiling member 543d.

[0106] Furthermore, as shown in Figure 15, the second cylindrical section 544 is formed by a part of one of the pair of first wall members 543a and 543b of the first cylindrical section 543 described above (in this third modified example, the first wall member 543b) (in this third modified example, the front end), a second wall member 544a positioned opposite to the part of the one first wall member, a part of the bottom wall 41a, and a second ceiling member 544b provided on the second casing 542 side and covering both the one first wall member and the second wall member 544a.

[0107] The second wall member 544a is a wall member provided perpendicularly from the bottom wall 41a of the first casing 541 and along the bottom wall 41a. The second wall member 544a is arranged parallel to and opposite a part of the one first wall member (first wall member 543b). The second ceiling member 544b is a pair of ceiling members to which the upper ends of the one first wall member and the second wall member 544a are connected, and is provided on the second casing 542 side, covering the one first wall member and the second wall member 544a. In this third modified example, it can be said that a part of the upper wall 542a of the second casing 542 forms the second ceiling member 544b.

[0108] Furthermore, as shown in Figure 13, the folded pipe section 545 is formed by a third wall member 545c which is formed in a U-shape on the first casing 541 and arranged to connect the first cylindrical pipe section 543 and the second cylindrical pipe section 544, a third ceiling member 545d which is provided on the second casing 542 side and covers the third wall member 545c, and a part of the bottom wall 41a of the first casing 541.

[0109] The third wall member 545c is a wall member provided perpendicularly from the bottom wall 41a of the first casing 541. As shown in Figure 17, the third wall member 545c comprises a wall member 544c1 positioned along the first wall member 543a and having its front end connected to the rear end of the first wall member 543a, a wall member 544c2 positioned along the second wall member 544a and having its front end connected to the rear end of the second wall member 544a, and a wall member 544c3 which is part of the side wall 41b and connects wall member 544c1 and wall member 544c2.

[0110] The third ceiling member 545d is a ceiling member to which the upper end of the third wall member 545c is connected, and is provided on the second casing 542 side and covers the third wall member 545c. In this third modified example, it can be said that a part of the upper wall 542a of the second casing 542 forms the third ceiling member 545d.

[0111] The folded bottom portion 545a is the wall member 544c3 of the third wall member 545c. The folded cylindrical portion 545b is a cylindrical portion formed from the wall member 544c1 of the third wall member 545c, the wall member 544c2 of the third wall member 545c, the third ceiling member 545d of the second casing 542, and a part of the bottom wall 41a of the first casing 541.

[0112] In this resonator 530, the sound-dampening chamber 531 is located within an internal space partitioned by a first casing 541 and a second casing 542, similar to the sound-dampening chamber 31 described above. The sound-dampening chamber 531 communicates with the intake pipe 12 via an internal flow path 532 and a connecting pipe 22. In other words, the sound-dampening chamber 531 can be described as the internal space other than the internal flow path 532.

[0113] In the resonator 530, as shown in Figure 13, the internal flow path 532 comprises a first internal flow path 532a of a first cylindrical section 543, one end (front end) of which is connected to the connecting pipe 22; a second internal flow path 532b of a second cylindrical section 544, which is arranged alongside the first cylindrical section 543; and a third internal flow path 532c of a folded pipe section 545 that connects the first cylindrical section 543 and the second cylindrical section 544 by folding back. The total length of the internal flow path 532 is the sum of the flow path length La of the first internal flow path 532a, the flow path length Lb of the second internal flow path 532b, and the flow path length Lc of the third internal flow path 532c.

[0114] The first internal channel 532a is a channel formed by the inner space of the first cylindrical section 543. In the first internal channel 532a, sound travels in the same way as in the internal channel 32a described above, so the channel length La of the first internal channel 532a is the axial length of the first cylindrical section 543. The second internal channel 532b is a channel formed by the inner space of the second cylindrical section 544. In the second internal channel 532b, sound travels in the same way as in the first internal channel 532a described above, so the channel length Lb of the second internal channel 532b is the axial length of the second cylindrical section 544.

[0115] The third internal channel 532c is a channel formed by the internal space of the folded pipe section 545. In the third internal channel 532c, similar to the folded channel 32c described above, sound that has propagated through the first internal channel 532a enters the second internal channel 532b while reflecting off the inner wall surface of the third internal channel 532c. For example, the centerline of the third internal channel 532c can be a curve (e.g., semicircular or semielliptical) connecting the average propagation path of the first internal channel 532a and the average path of the second internal channel 532b. Therefore, the channel length Lc of the third internal channel 532c can be set to the length of this curve.

[0116] In the intake device 520 according to this third modified example, the silencer chamber 531 is an internal space formed by a first casing 541 having a first wall (bottom wall 41a) with an opening 41a1 connected to the communication pipe 22, and a second casing 542 assembled to the first casing 541, and the first cylindrical section 543 includes a pair of first wall members 543a, 543b connected to the opening 41a1 of the first casing 541 and provided along the bottom wall 41a of the first casing 541, and a first ceiling member 543d provided on the second casing 542 side and covering the pair of first wall members 543a, 543b, and the second cylindrical section 5 Preferably, 44 includes either one of a pair of first wall members 543a, 543b, a second wall member 544a positioned opposite one of the first wall members 543a, 543b, and a second ceiling member 544b provided on the second casing 542 side and covering both one of the first wall members 543a, 543b and the second wall member 544a. The folded pipe section 545 preferably includes a third wall member 545c formed in a U shape on the first casing 541 and positioned to connect the first pipe section 543 and the second pipe section 544, and a third ceiling member 545d provided on the second casing 542 side and covering the third wall member 545c. According to this, it is possible to manufacture a sound-dampening chamber 531 and, consequently, an intake device 520 having parallel-tube type internal flow paths horizontally along the bottom wall 41a by simply connecting the first casing 541 and the second casing 542 together.

[0117] Furthermore, although the folded pipe sections 245 and 545 described above are formed in a U-shape, they are not limited to this and may be formed in any other shape that allows the flow path to be folded back.

[0118] (Effects and mechanisms of the embodiment) The intake devices 20, 220, 420, and 520 according to the above-described embodiment include an intake pipe 12 for drawing air into an internal combustion engine 11, silencer chambers 31, 131, 231, 431, and 531 connected to the intake pipe 12 via a connecting pipe 22 for silencing the intake noise generated in the intake pipe 12, and internal passages 32, 132, 232, 332, 432, and 532 which are flow paths formed by extending the connecting pipe 22 within the silencer chambers 31, 131, 231, 431, and 531 and then folding back.

[0119] With this intake device 20,220,420,520, it is possible to provide internal passages 32,132,232,332,432,532 in the sound-dampening chambers 31,131,231,431,531 (limited space) whose flow path length can be set to any length. Therefore, it is possible to provide an intake device in which the length of the connecting pipe 22 (communication passage) can be adjusted without increasing the size of the device itself.

[0120] Furthermore, in the intake device 20,420 according to this embodiment, it is preferable that the internal passages 32,132,432 include inner passages 32a,432a of inner cylinders 43,443, one end of which is connected to the connecting pipe 22, and outer passages 32b,432b formed between the inner cylinders 43,443 and bottomed cylindrical outer cylinders 44,444, which are arranged to cover the other end openings of the inner cylinders 43,443. This makes it possible to form the internal passages with a simple configuration (double pipe).

[0121] Furthermore, in the intake devices 220, 520 according to this embodiment, it is preferable that the internal passages 232, 532 include first internal passages 232a, 532a of first cylindrical sections 243, 543, one end of which is connected to the connecting pipe 22; second internal passages 232b, 532b of second cylindrical sections 244, 544, which are arranged parallel to the first cylindrical sections 243, 543; and third internal passages 232c, 532c of folded pipe sections 245, 545, which are arranged to connect the first cylindrical sections 243, 543 and the second cylindrical sections 244, 544. This makes it possible to form internal passages with a simple configuration (parallel pipes).

[0122] Furthermore, the resonators 30, 130, 230, 430, and 530 according to this embodiment are connected to the air transport pipe (intake pipe 12) via a connecting pipe 22 and include sound-dampening chambers 31, 131, 231, 431, and 531 that silence the sound generated in the transport pipe, and internal flow paths 32, 132, 232, 332, 432, and 532 that are extensions of the connecting pipe 22 within the sound-dampening chambers 31, 131, 231, 431, and 531 and are formed by folding back. With these resonators 30, 130, 230, 430, and 530, it becomes possible to provide internal flow paths 32, 132, 232, 332, 432, and 532 within the sound-dampening chambers 31, 131, 231, 431, and 531 (limited space) whose flow path length can be set to any length. Therefore, it is possible to provide a resonator in which the length of the connecting pipe 22 (communication passage) can be adjusted without increasing the size of the device itself.

[0123] Furthermore, in the resonators 30, 130, 430 according to this embodiment, it is preferable that the internal flow paths 32, 132, 432 include inner flow paths 32a, 432a of inner cylinders 43, 443, one end of which is connected to the connecting pipe 22, and outer flow paths 32b, 432b formed between the bottomed cylindrical outer cylinders 44, 444, which are arranged to cover the other end openings of the inner cylinders 43, 443 and the inner cylinders 43, 443. This makes it possible to form the internal flow paths with a simple configuration (double pipe).

[0124] Furthermore, in the resonators 230, 530 according to this embodiment, it is preferable that the internal flow paths 232, 532 include first internal flow paths 232a, 532a of first cylindrical sections 243, 543, one end of which is connected to the connecting pipe 22; second internal flow paths 232b, 532b of second cylindrical sections 244, 544, which are arranged parallel to the first cylindrical sections 243, 543; and third internal flow paths 232c, 532c of folded pipe sections 245, 545, which are arranged to connect the first cylindrical sections 243, 543 and the second cylindrical sections 244, 544. This makes it possible to form internal flow paths with a simple configuration (parallel pipes). [Explanation of symbols]

[0125] 11...Internal combustion engine, 12...Intake pipe, 20, 220, 420, 520...Intake system, 22...Connecting pipe, 30, 130, 230, 430, 530...Resonator, 31, 131, 231, 431, 531...Silencer chamber, 41, 241, 441, 541...First casing, 41a...Bottom wall (first wall), 41a1...Opening, 42, 242, 442, 542...Second casing, 42a...Top wall (second wall), 32, 132, 232, 332, 432, 532...Internal flow path, 32a, 432a...Inner flow path, 32b, 432b...Outer Side passage, 43, 443...inner cylinder, 44, 444...outer cylinder, 232a, 532a...first internal passage, 232b, 532b...second internal passage, 232c, 532c...third internal passage, 243, 543...first cylindrical section, 244, 544...second cylindrical section, 245, 545...folded pipe section, 443a, 443b, 543a, 543b...pair of first wall members, 443d, 543d...first ceiling member, 444c, 544a...second wall member, 444d, 544b...second ceiling member, 545c...third wall member, 545d...third ceiling member.

Claims

1. An intake manifold for drawing air into an internal combustion engine, A sound-dampening chamber connected to the intake pipe via a connecting pipe, which silences the intake noise generated in the intake pipe, A flow path formed by extending the connecting pipe within the sound-absorbing chamber, and an internal flow path formed by folding back, Equipped with, The internal flow path comprises an inner flow path of an inner cylinder connected at one end to the connecting pipe, and an outer flow path formed between a bottomed cylindrical outer cylinder and the inner cylinder, which is arranged to cover the opening at the other end of the inner cylinder. The sound-dampening chamber is an internal space formed by a first casing having a first wall with an opening connected to the communication pipe, and a second casing assembled to the first casing. The inner cylinder includes a pair of first wall members connected to the opening of the first casing and provided along the first wall of the first casing, and a first ceiling member provided on the second casing side and covering the pair of first wall members. The intake device is characterized in that the outer cylinder includes a second wall member formed in a U shape on the first casing and arranged to surround the pair of first wall members, and a second ceiling member provided on the second casing side and covering the second wall member.

2. An intake manifold for drawing air into an internal combustion engine, A sound-dampening chamber connected to the intake pipe via a connecting pipe, which silences the intake noise generated in the intake pipe, A flow path formed by extending the connecting pipe within the sound-absorbing chamber, and an internal flow path formed by folding back, Equipped with, The internal flow path comprises a first internal flow path of a first cylindrical section, one end of which is connected to the connecting pipe; a second internal flow path of a second cylindrical section, which is arranged alongside the first cylindrical section; and a third internal flow path of a folded pipe section, which is arranged to connect the first cylindrical section and the second cylindrical section. The sound-dampening chamber is an internal space formed by a first casing having a first wall with an opening connected to the communication pipe, and a second casing assembled to the first casing. The first cylindrical section includes a pair of first wall members connected to the opening of the first casing and provided along the first wall of the first casing, and a first ceiling member provided on the second casing side and covering the pair of first wall members. The second cylindrical section includes one of the pair of first wall members, a second wall member positioned opposite to the first wall member, and a second ceiling member provided on the second casing side that covers both the first wall member and the second wall member. The intake device is characterized in that the folded pipe section includes a third wall member formed in a U shape on the first casing and arranged to connect the first cylindrical pipe section and the second cylindrical pipe section, and a third ceiling member provided on the second casing side and covering the third wall member.

3. An intake manifold for drawing air into an internal combustion engine, A sound-dampening chamber connected to the intake pipe via a connecting pipe, which silences the intake noise generated in the intake pipe, A flow path formed by extending the connecting pipe within the sound-absorbing chamber, and an internal flow path formed by folding back, Equipped with, The internal flow path comprises an inner flow path of an inner cylinder connected at one end to the connecting pipe, and an outer flow path formed between a bottomed cylindrical outer cylinder and the inner cylinder, which is arranged to cover the opening at the other end of the inner cylinder. The sound-dampening chamber is an internal space formed by a first casing having a first wall with an opening connected to the communication pipe, and a second casing assembled to the first casing. The inner cylinder is a cylindrical member connected to the opening of the first casing and provided perpendicular to the first wall. The outer cylinder is a cylindrical member provided perpendicular to the second wall of the second casing, which is opposite the first wall of the first casing. The outer cylinder has an outer cylinder bottom and an outer cylinder body, and an annular recess is formed on the inner bottom surface of the outer cylinder bottom. An air intake device characterized by having a protrusion formed at the center of the bottom of the outer cylinder.

4. The intake device according to claim 3, characterized in that the cross-section of the recess is formed in a curved shape in which the curvature decreases as you move outward from the center of the bottom of the outer cylinder.

5. A sound-dampening chamber is connected to a gas transport pipe via a connecting pipe, and the sound generated in the transport pipe is silenced. A flow path formed by extending the connecting pipe within the sound-absorbing chamber, and an internal flow path formed by folding back, Equipped with, A resonator characterized by satisfying either condition (A) or (B) below. (A) The internal flow path comprises an inner flow path of an inner cylinder connected at one end to the connecting pipe, and an outer flow path formed between a bottomed cylindrical outer cylinder and the inner cylinder, which is arranged to cover the opening at the other end of the inner cylinder. The sound-dampening chamber is an internal space formed by a first casing having a first wall with an opening connected to the communication pipe, and a second casing assembled to the first casing. The inner cylinder includes a pair of first wall members connected to the opening of the first casing and provided along the first wall of the first casing, and a first ceiling member provided on the second casing side and covering the pair of first wall members. The outer cylinder includes a second wall member formed in a U-shape on the first casing and arranged to surround the pair of first wall members, and a second ceiling member provided on the second casing side and covering the second wall member. (B) The internal flow path comprises a first internal flow path of a first cylindrical section, one end of which is connected to the connecting pipe; a second internal flow path of a second cylindrical section, which is arranged alongside the first cylindrical section; and a third internal flow path of a folded pipe section, which is arranged to connect the first cylindrical section and the second cylindrical section. The sound-dampening chamber is an internal space formed by a first casing having a first wall with an opening connected to the communication pipe, and a second casing assembled to the first casing. The first cylindrical section includes a pair of first wall members connected to the opening of the first casing and provided along the first wall of the first casing, and a first ceiling member provided on the second casing side and covering the pair of first wall members. The second cylindrical section includes one of the pair of first wall members, a second wall member positioned opposite to the first wall member, and a second ceiling member provided on the second casing side that covers both the first wall member and the second wall member. The folded pipe section includes a third wall member formed in a U-shape on the first casing and arranged to connect the first cylindrical pipe section and the second cylindrical pipe section, and a third ceiling member provided on the second casing side and covering the third wall member.

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