JP2004293456A - Muffler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a muffler capable of being mounted to the piping line such as an intake and exhaust pipe or the like in a small space. <P>SOLUTION: The sound absorbing device A is mounted to an end part 11 of the piping 10 such as the intake and exhaust pipe or the like. The sound absorbing device has the connection side end opened to the piping 10 side, and it is formed by a double tube 12 with a tip end part side closed. The length L of the double tube 12 is formed to be the length of 1/4 of the frequency to be muffled. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a muffler attached to a pipe such as an intake and exhaust device of an engine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as shown in FIG. 5, an intake / exhaust system for an engine has an intake manifold 52 of an engine 50, an intake pipe 52 connected thereto, an air cleaner 53 connected in the middle of the intake pipe 52, and a noise source connected to the intake pipe 52. A resonator 54 for reduction is attached.
[0003]
An exhaust pipe 56 is connected to the exhaust manifold 55, and a catalyst combustor 57 and a muffler 58 are connected to the exhaust pipe 56.
[0004]
The resonator 54 and the muffler 58 are connected in the middle of the intake and exhaust pipes 52 and 56, and mute due to interference, resonance, detour, and the like, as described in Patent Documents 1 to 4.
[0005]
[Patent Document 1]
JP-A-7-229414 [Patent Document 2]
Japanese Patent Application Laid-Open No. 9-177534 [Patent Document 3]
JP-A-5-256120 [Patent Document 4]
Japanese Patent Application Laid-Open No. 2000-110543
[Problems to be solved by the invention]
However, there are various structures in the middle of the intake pipe 52 and the exhaust pipe 56, and in order to avoid these structures, the intake pipe 52 and the exhaust pipe 56 are mostly bent. In some cases, it may not be easy to arrange a muffler or the like due to space, and as a result, there is a problem that a necessary reduction of a frequency range cannot be achieved.
[0007]
Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a noise reduction device that can be attached to a pipe such as an intake / exhaust pipe in a small space.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a muffler attached to an end of a pipe such as an intake / exhaust pipe, wherein a connection side end of the pipe is opened to a pipe side and a tip end side is closed. This is a silencer formed by a double tube.
[0009]
According to a second aspect of the present invention, there is provided the muffler according to the first aspect, wherein the length of the double pipe is formed to be １ ／ of the frequency to be silenced.
[0010]
According to a third aspect of the present invention, the inner diameter of the inner pipe of the double pipe is formed to be substantially the same as the inner diameter of the pipe, the inner diameter of the outer pipe is formed larger than the inner diameter of the pipe, and the pipe and the outer pipe are connected. 3. The muffler according to claim 1, wherein the mufflers are connected by different diameter pipes.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
[0012]
In FIG. 1, reference numeral 10 denotes a pipeline such as an intake / exhaust pipe for sucking and discharging a fluid.
[0013]
The silencer A is constituted by a double pipe 12 in which the connection side end of the pipe 10 is opened to the pipe 10 side and the tip end side is closed.
[0014]
The double pipe 12 has an opening 13 on the pipe 10 side and an inner pipe 15 and an outer pipe 16 having a closing plate 14 at the distal end, and a different-diameter pipe on the pipe 10 side of the outer pipe 16. The connecting pipe 18 for fitting into the pipe 10 is formed integrally with the different-diameter pipe 17.
[0015]
The material of the silencer A may be a synthetic resin or a metal if applied to an intake pipe, but a metal or the like is used if applied to an exhaust pipe.
[0016]
The inner diameter φi of the inner pipe 15 is formed to be substantially the same as the inner diameter φ10 of the pipe 10, and the inner diameter φo of the outer pipe 16 is larger than the inner diameter φi of the inner pipe 15 and is formed by the target frequency to be silenced. Is increased, the reduction width of the target frequency can be increased. In this case, the area of the opening 13 (blocking plate 14) may be equal to or larger than the area of the inner tube 15.
[0017]
Further, assuming that the target frequency is Fr, the sound speed is C (m / s), and the order is n, the length L of the double tube 12 is Fr = (2n-1) C / 4L, and the length L of the double tube 12 resonates to reduce the sound deadening effect. Therefore, in order to suppress the sound in the first mode, the wavelength is set to ４ of the wavelength of the target frequency.
[0018]
That is, if the target frequency is 850 Hz or less (about 40 cm or less in the wavelength in the air), L 空 気 10 cm or less is sufficient.
[0019]
Further, the length α of the different diameter pipe 17 is determined while experimentally confirming the reduction effect.
[0020]
In the above description, for example, when exhaust gas is discharged from the pipe 10 toward the silencer A, the noise propagates from the different-diameter pipe 17 to the outside through the inner pipe 15 (sound pressure is zero). The part enters between the inner pipe 15 and the outer pipe 16 from the different diameter pipe 17 through the opening 13 of the double pipe 12, is reflected (the maximum sound pressure, the particle velocity is zero) by the closing plate 14, Since the noise is narrowed at 17 and propagates in the pipe 10 in the opposite direction, and the reflected noise has a half wavelength shift relationship with the noise of the pipe 10, the noise is attenuated by interference or resonance. . In particular, since this reflected sound propagates along the axial direction of the pipeline 10, the attenuation range is wider and effective noise can be eliminated.
[0021]
This silencer A is simply attached to the end 11 of the pipeline 10, and can be easily attached even in a pipeline where there is not enough space.
[0022]
FIG. 2 shows another embodiment of the present invention, in which a projecting portion 20 is formed on the pipe 10 side so that the connecting pipe 18 of the silencing device A can be positioned by contacting the projecting portion 20. The other configuration is the same as that of the embodiment of FIG.
[0023]
FIG. 3 shows a configuration in which a reduced-diameter portion 21 is formed between the different-diameter pipe 17 and the connecting pipe 18 for positioning, and the other configuration is the same as that of the embodiment of FIG.
[0024]
FIG. 4 shows an example in which the muffler A is formed by separately forming the double pipe portion 12a and the different-diameter pipe 17a. The double pipe 12a connects the inner pipe 15a and the outer pipe 16a with a closing plate 14a. The different-diameter pipe 17a is formed of a connecting pipe 25 fitted to the conduit 10, a connecting pipe 26 fitted to the double pipe 12a, and a different-diameter pipe connecting the two connecting pipes 25, 26. It is formed integrally by a tube portion 27.
[0025]
In the embodiment shown in FIG. 4, it is possible to change the position of the double pipe 12a to be inserted into the connection pipe part 26, thereby making it possible to adjust the position at which an appropriate noise reduction effect is obtained.
[0026]
In the above-described embodiment, an example has been described in which the exhaust sound is attenuated. However, the principle is the same for the intake sound.
[0027]
Further, even if the silencer 58 and the resonator 54 are attached to the intake / exhaust device of the engine shown in FIG. 5, the silencer A of the present invention is only attached to the end. If attached to the part, a further silencing effect can be obtained.
[0028]
【The invention's effect】
In short, according to the present invention, since it is attached to the end of the pipe to mute the sound, it can be easily attached to almost all the pipes.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing another embodiment of the present invention.
FIG. 3 is a cross-sectional view showing another embodiment of the present invention.
FIG. 4 is a cross-sectional view showing another embodiment of the present invention.
FIG. 5 is a perspective view showing an intake and exhaust device of the engine.
[Explanation of symbols]
10 Pipeline 11 End 12 Double pipe 15 Inner pipe 16 Outer pipe

Claims (3)

A silencer attached to an end of a pipe such as an intake / exhaust pipe, wherein the silencer is formed by a double pipe having a connection end open to the pipe side and a closed end. 2. The silencer according to claim 1, wherein the length of the double pipe is formed to be 1/4 of the frequency to be silenced. The inner diameter of the inner pipe of the double pipe is formed to be substantially the same as the inner diameter of the pipe, the inner diameter of the outer pipe is formed larger than the inner diameter of the pipe, and the pipe and the outer pipe are connected by different diameter pipes. The muffler according to claim 1.

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