JP2019105214A - Muffling device - Google Patents

Abstract

To provide a muffling device that can reduce noise sufficiently, save a space and suppress degradation in ventilation resistance of an intake passage.MEANS: A muffling device includes: a first resonant chamber with a predetermined volume; and a first communication pipe for communicating between the first resonant chamber and an intake passage for an internal combustion engine. A second communication pipe that is discontinuously formed from the communication pipe and has an opening part and a second resonant chamber that is formed in one end of the second communication pipe are formed inside the first resonant chamber.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a noise reduction device, and more particularly to a noise reduction device provided in an intake passage of an internal combustion engine to reduce intake noise.

  Pulsating noise is generated by opening and closing an intake valve by driving an internal combustion engine, and it is known that the pulsating noise becomes intake noise. In order to reduce this intake noise, a resonator or a side branch type resonator (hereinafter referred to as There is known a muffling apparatus in which a "side branch" or the like is formed continuously with an intake passage.

  The resonator as the muffling apparatus has a communicating pipe which branches from the resonator body of a predetermined volume and the intake passage and brings the intake passage and the resonator body into communication with each other, and noise of a frequency calculated based on Helmholtz's resonance theory etc. The volume of the resonator body is determined to reduce the

  The side branch is a bottomed cylindrical tubular body having a predetermined uniform cross section, and branches from the intake passage. The side branch appropriately determines the total length of the side branch according to the frequency to be reduced.

  Further, it is known that noise generated from an intake passage communicating with an internal combustion engine is intake noise caused by intermittent flow of air due to suction of air when an intake valve is opened. This intake noise includes various frequencies, and in order to attenuate specific frequencies that may cause unpleasant noise, while appropriately adjusting the volume of the above-mentioned resonator and the length of the side branch, these resonators and the side branch are It is arranged to be branched off from the intake passage, and such a silencer is known in various forms.

  However, according to the conventional configuration of the resonator and the side branch, it is necessary to provide a plurality of communicating pipes in the intake passage, and there is a problem that installing the plurality of silencers in the intake passage enlarges the intake passage. . Various structures are known to suppress such an increase in the size of the intake passage.

  The noise suppressor described in Patent Document 1 is a box having a top wall and a bottom wall, in which a cylinder whose upper end is open and an opening is provided in a side wall and a neck is formed around the opening is provided with a central hole. With a configuration in which it is inserted into the central hole of the upper wall and the peripheral edge of the central hole is fixed to the side wall between the upper end of the cylindrical portion and the opening and the lower end of the cylindrical portion is fixed to the steam bottom wall There is.

  The noise reduction device described in Patent Document 2 includes a main body case disposed outside a flow passage through which gas can pass and having a predetermined inner volume, and a resonance pipe connecting the flow passage and the main case in communication. A partition member disposed in the main body case and partitioning the inside of the main body case into a plurality of resonance chambers; and a plurality of predetermined frequency components of propagation sound propagating in the flow pipe, the resonance pipe and the resonance chamber The resonator is designed to be reduced by the resonance action of the above, and the partition member in the main body case is extended to the connecting portion of the flow pipe and the resonance pipe, and the inside of the resonance pipe is divided into plural parts by the extension. Is equipped.

  The noise reduction device described in Patent Document 3 is connected to a flow pipe through which gas can flow, and is a multi-chamber resonator having a plurality of resonance chambers inside, and is hollow having a communicating pipe portion connected to the flow pipe. And a small communication tube portion having an outer diameter smaller than the inner diameter of the communication tube portion, and a small hollow case formed smaller than the main body case, and A small case is housed, and the inside of the body case is divided into a small case resonance chamber consisting of the inside of the small case and a body resonance chamber consisting of the remaining part, and the small communication pipe portion is housed in the communication pipe portion The communication tube portion is divided into a remaining portion which causes the communication tube and the small case resonance chamber to communicate with each other.

Japanese Utility Model Publication No. 6-25550 Unexamined-Japanese-Patent No. 5-240120 JP, 2007-315219, A

  However, according to the configuration of the conventional muffling apparatus described above, a plurality of resonators and side branches are integrally formed to muffle a plurality of frequencies, and for example, when it is desired to muffle a low frequency band, a resonator Because it is necessary to increase the volume of the above, there is a problem that it is difficult to miniaturize the entire silencer.

  Therefore, the present invention has been made in view of the above problems, and noise reduction can be sufficiently reduced, space saving can be achieved, and a noise reduction device capable of suppressing the deterioration of the ventilation resistance of the intake passage. Intended to provide.

  A silencer according to the present invention is a silencer having a first resonance chamber of a predetermined volume, and a first communicating pipe communicating the first resonance chamber with an intake passage of an internal combustion engine, A second communication pipe formed discontinuously from the first communication pipe and having an opening in one resonance chamber, and a second resonance chamber formed at one end of the second communication pipe It is characterized by being.

  Further, in the muffler according to the present invention, the second resonance chamber is extended from each of the opposing wall surfaces of the first resonance chamber, and the first cylindrical member and the second resonance chamber have an open end. The first tubular member is inserted into the second tubular member through a predetermined gap, and the first tubular member and the second tubular member are inserted into the second tubular member. It is preferable to form the second communication pipe by the overlapping portion of the members.

  In the noise suppressor according to the present invention, the length of the second communication pipe can be adjusted by adjusting the overlapping length of the first cylindrical member and the second cylindrical member. Is preferred.

  Further, in the noise reduction device according to the present invention, the first resonance chamber includes at least one wall surface of the opposing wall surfaces, and includes the first tubular member extended from the one wall surface. A bottomed cylindrical second member having a bottomed cylindrical first divided body and the other wall surface of the opposing wall surface, and including the second cylindrical member extended from the other wall surface It is preferable to provide the following.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and subcombinations of these features may also be the invention.

  The silencer according to the present invention is formed at a first communication pipe discontinuously formed from the first communication pipe in the first resonance chamber and having a second communication pipe having an opening and one end of the second communication pipe. Since the second resonance chamber is formed, the frequency depending on the volume of the second resonance chamber can be attenuated without affecting the attenuation effect of the frequency depending on the volume of the first resonance chamber. Therefore, the plurality of frequencies can be attenuated to sufficiently reduce the noise, and the space can be saved.

The figure for demonstrating the outline | summary of the silencer which concerns on this embodiment. The graph for demonstrating the muffling effect of the muffling apparatus which concerns on this embodiment. The figure for demonstrating the modification of the silencer which concerns on this embodiment. Sectional drawing for demonstrating the structure of the modification of the silencer which concerns on this embodiment. The graph for explaining the muffling effect of the modification of the muffling device concerning this embodiment.

  Hereinafter, preferred embodiments for carrying out the present invention will be described using the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  FIG. 1 is a view for explaining an outline of the noise reduction device according to the present embodiment, FIG. 2 is a graph for explaining a noise reduction effect of the noise reduction device according to the present embodiment, and FIG. It is a figure for demonstrating the modification of the silencer based on embodiment, FIG. 4 is a sectional view for demonstrating the structure of the modification of the silencer based on this embodiment, FIG. 5 is this implementation It is a graph for demonstrating the muffling effect of the modification of the muffling apparatus which concerns on a form.

  As shown in FIG. 1, the noise reduction device 1 according to the present embodiment is attached to an intake passage 12 for introducing outside air filtered to an internal combustion engine after filtering dust and the like by an air cleaner (not shown) outside air. The intake passage 12 is a cylindrical member having a smooth inner wall, and various cross-sectional shapes such as a circle, an ellipse, and a polygon are known.

  Further, the noise reduction device 1 according to the present embodiment includes a first resonance chamber 11 having a predetermined volume, and a first communication pipe 13 communicating the first resonance chamber 11 with the intake passage 12. . The first resonance chamber 11 can be formed into various shapes such as a rectangular parallelepiped or a cylindrical shape, and its volume is determined based on Helmholtz's resonance theory according to the frequency to be attenuated.

The effect frequency F1 of the first resonance chamber 11 and the first communication tube 13 corresponds to the volume V (L) of the first resonance chamber 11 and the length L (mm) of the first communication tube 13 and the first communication The cross-sectional area S (mm ² ) of the pipe 13 can be obtained by the following formula.

ここで、ｃは常温での音速（３４３ｍ／ｓ）とする。

Here, c is the speed of sound at normal temperature (343 m / s).

  In addition, a second resonance chamber 20 arranged to be erected from the bottom wall 14 of the first resonance chamber 11 is formed inside the first resonance chamber 11, and the second resonance chamber 20 is formed. A second communication pipe 21 is formed discontinuously with the first communication pipe 13 and has an opening 22 at one end. The second resonance chamber can be formed into various shapes such as a rectangular parallelepiped or a cylinder like the first resonance chamber 11 described above, and the volume thereof can be determined according to Helmholtz's resonance theory according to the frequency to be attenuated. It is decided based on.

  The effect frequency F2 of the second resonance chamber 20 and the second communication tube 21 was found to be determined by the following equation from the verification result of the inventors.

ここで、ｃは、常温での音速、Ｖ２は、第２の共鳴室２０の容積（Ｌ）、Ｓ２は、第２の連通管２１の断面積（ｍｍ²）、Ｌ２は、第２の連通管２１の長さ（ｍｍ）、αは、第１の連通管１３の吸気通路１２の設置位置によって決定される変数である。

Here, c is the speed of sound at normal temperature, V2 is the volume (L) of the second resonance chamber 20, S2 is the cross-sectional area (mm ² ) of the ^second communicating pipe 21, and L2 is the second communication The length (mm) of the pipe 21 and α are variables determined by the installation position of the intake passage 12 of the first communication pipe 13.

  Although the first resonance chamber 11, the first communication tube 13, the second resonance chamber 20, and the second communication tube 21 may be formed of any material, for example, they are formed of a synthetic resin. For example, thermoplastic synthetic resins such as polypropylene resins and polyamide resins are preferably used. Also, the first resonance chamber 11, the first communication tube 13, the second resonance chamber 20, and the second communication tube 21 may be integrally formed, or the second resonance chamber 20 and the second communication tube 21 may be formed integrally. After the communicating pipe 21 is incorporated into the first resonance chamber 11, the separately constructed first communicating pipe 13 may be combined by a known coupling means.

  The first communication pipe 13 and the second communication pipe 21 are cylindrical members having a substantially constant cross-sectional area, and the cross-sectional area of the first communication pipe 13 corresponds to the intake passage 12 or the first resonance. The cross-sectional area of the second communication tube 21 is smaller than the second resonance chamber. In addition, with a cylindrical shape, the cross-sectional shape is not limited to a circle, and may be formed, for example, in a polygonal shape.

  The result of having conducted experiment about the muffling effect of the muffling apparatus 1 which concerns on this embodiment formed in this way is a graph shown in FIG. The embodiment in the graph shown in FIG. 2 confirms the muffling effect for each frequency using the muffling apparatus 1 described above. In the comparative example, the second resonance chamber 20 is placed in the first resonance chamber 11. It is the graph which confirmed the muffling effect at the time of comprising a muffling device only in the 1st resonance chamber 11 like the conventional resonator main body, without forming. FIG. 2 compares the attenuations of the example and the comparative example, and it is determined that the higher the attenuation on the vertical axis, the more effective.

  As is clear from FIG. 2, with regard to F1 which is the effect frequency of the first resonance chamber 11 and the first communicating pipe 13, the same silencing effect can be confirmed in the example and the comparative example. On the other hand, in the example, together with the muffling effect by F1, the muffling effect at the effect frequency F2 by the second resonance chamber 20 and the second communicating pipe 21 can also be confirmed, and the effect frequency is compared with the comparative example. It can be confirmed that it is superior in

  Moreover, since the noise reduction device 1 according to the present embodiment can obtain a plurality of noise reduction effects by forming the second resonance chamber 20 inside the first resonance chamber 11, the first resonance chamber 11 can be obtained. Since the muffling effect of a plurality of effect frequencies can be obtained without increasing the size of the sound effect, the effect frequency can be increased while the size of the muffling apparatus 1 is suppressed.

  In addition, since the first communication pipe 13 branched from the intake passage 12 is single in the silencer device 1 according to the present embodiment, the holes formed in the inner wall of the intake passage 12 along with the installation of the silencer device 1 The number can be reduced, and the deterioration of the ventilation resistance accompanying the increase in the number of holes can be suppressed.

  Furthermore, since the noise reduction device 1 according to the present embodiment can set the effect frequency by the above-described Equations 1 and 2, the first resonance chamber 11 or the second resonance chamber 11 can be set according to the effect frequency to be attenuated. The effect frequency can be easily adjusted by appropriately setting the volume of the resonance chamber 20 and the length and the cross-sectional area of the first communication pipe 13 and the second communication pipe 21.

  Further, although the noise suppressor 1 according to the present embodiment has described the case where the second resonance chamber 20 is formed to be placed on the bottom wall 14 of the first resonance chamber 11 as described above, The method of forming the second resonance chamber is not limited to this. For example, as shown in FIGS. 3 to 4, a first cylindrical divided body 16 and a second divided body 17 with a bottomed cylindrical shape having side walls 15 (as opposed wall surfaces) of the first resonance chamber 11 ′. You may constitute by combining. This modification will be described below.

  A first tubular member 31 and a second tubular member 32 extending from the side wall 15 are formed in the first divided body 16 and the second divided body 17, respectively. As shown in FIG. 4, the first tubular member 31 is formed larger than the outer diameter of the second tubular member 32 so that the second tubular member 32 can be inserted with a predetermined gap. It is done. Further, it is preferable that the tips of the first tubular member 31 and the second tubular member 32 overlap with each other, and the length of this overlapping portion is configured to be changeable as appropriate. The tips of the first tubular member 31 and the second tubular member 32 are not in contact with the side wall 15 of the second divided body 17 or the side wall 15 of the first divided body 16 facing each other. The first tubular member 31 and the second tubular member 32 each have an open end. In addition, the cross-sectional shape of the 1st cylindrical member 31 and the 2nd cylindrical member 32 may not be restricted circularly, for example, may be formed in polygonal shape.

  The noise reduction device 1 'according to the modification configured in this way can configure the space formed by the first cylindrical member 31 and the second cylindrical member 32 as the second resonance chamber 20'. A substantially annular gap between the inner surface of the first tubular member 31 and the outer surface of the second tubular member 32 in the overlapping portion of the first tubular member 31 and the second tubular member 32; The effective frequency is determined by setting the area as the cross-sectional area of the second communication pipe 21 'and the length of the overlapping portion of the first cylindrical member 31 and the second cylindrical member 32 as the length of the second communication pipe 21'. be able to.

  In the modification of the silencer according to the present embodiment, for example, only one of the first tubular member 31 and the second tubular member 32 may constitute the second resonance chamber. In this case, the same muffling effect as that of the conventional side branch can be realized with only the first cylindrical member 31 or the second cylindrical member 32. At this time, it is preferable that the open ends of the first cylindrical member 31 and the second cylindrical member 32 be formed discontinuously with the first communication pipe 13.

  The result of having conducted experiment about the muffling effect of muffling apparatus 1 'which concerns on the modification of this embodiment formed in this way is a graph shown in FIG. The embodiment in the graph shown in FIG. 5 confirms the muffling effect for each frequency using the above-described muffling apparatus 1 ', and the comparative example uses the muffling apparatus similar to the comparative example in FIG. It is the graph which confirmed the muffling effect of. FIG. 5 compares the attenuations of the example and the comparative example as in FIG. 2, and it is determined that the higher the attenuation on the vertical axis, the more effective.

  As is clear from FIG. 5, with regard to F1 which is the effect frequency of the first resonance chamber 11 and the first communicating pipe 13, the same silencing effect can be confirmed in the example and the comparative example. On the other hand, in the embodiment, together with the muffling effect by F1, the effect frequency F2 by the second resonance chamber and the second communicating tube defined by the first cylindrical member 31 and the second cylindrical member 32. The muffling effect of the above can also be confirmed, and it can be confirmed that the effect frequency is superior to that of the comparative example.

  As described above, the silencers 1 and 1 'according to the present embodiment can effectively set the respective effect frequencies of the first resonance chamber, the first communication pipe, the second resonance chamber, and the second communication pipe. By reducing the frequency, a plurality of frequencies can be attenuated without adversely affecting the muffling effect of the first resonance chamber, and noise can be sufficiently reduced. Therefore, space can be saved, and a branch is taken from the intake passage. By suppressing the number of communicating pipes, it is possible to suppress the deterioration of the ventilation resistance of the intake passage.

  In the modification of the present embodiment, the case where the first cylindrical member 31 and the second cylindrical member 32 are formed in the first divided body 16 and the second divided body 17, respectively, has been described. However, the through-hole which the 1st cylindrical member 31 and the 2nd cylindrical member 32 can fit in is formed in the side wall 15, and the insertion amount of the 1st cylindrical member 31 and the 2nd cylindrical member 32 By adjusting, the lengths of the overlapping portions may be adjustable.

  Moreover, although the silencer according to the present embodiment has been described in the case where one second resonance chamber is formed in the first resonance chamber, even if a plurality of resonance chambers are formed in the first resonance chamber. I do not care. In this case, since the effective frequency increases according to the number of resonance chambers, it is possible to reduce noise in a wider range. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the present invention.

  1,1 'silencer, 11, 11' first resonance chamber, 12 intake passage, 13 first communication pipe, 14 bottom wall, 15 side wall, 16 first divided body, 17 second divided body, 20 , 20 'second resonance chamber, 21, 21' second communicating pipe, 22 opening, 31 first tubular member, 32 second tubular member.

Claims (4)

A silencer having a first resonance chamber of a predetermined volume, and a first communication pipe communicating the first resonance chamber with an intake passage of an internal combustion engine,
A second communication pipe formed discontinuously from the first communication pipe in the first resonance chamber and having an opening, and a second resonance chamber formed at one end of the second communication pipe A silencer according to the invention is formed. In the silencer according to claim 1,
The second resonance chamber extends from each of opposing wall surfaces of the first resonance chamber, and is defined by a first cylindrical member having an open end and a second cylindrical member.
The first tubular member is inserted into the second tubular member through a predetermined gap, and the second tubular member is overlapped by the overlapping portion of the first tubular member and the second tubular member. A silencer comprising a communicating pipe. In the silencer according to claim 2,
The length of the second communication pipe can be adjusted by adjusting the overlapping length of the first tubular member and the second tubular member. In the silencer according to claim 2 or 3,
The first resonance chamber includes at least one of the opposing wall surfaces, and a bottomed cylindrical first divided body including the first tubular member extended from the one wall surface. And a bottomed cylindrical second divided body including the other wall surface of the opposing wall surface and the second cylindrical member extended from the other wall surface. Muffler.

Images