JP7274310B2 - Silencer - Google Patents

Description

The present invention relates to silencers.

2. Description of the Related Art Conventionally, a vehicle such as an automobile having an internal combustion engine is provided with an exhaust pipe for leading out exhaust gas emitted from the internal combustion engine, and the exhaust pipe is provided with a muffler for reducing exhaust noise.

A muffler is required to have different performance depending on the rotation range of an internal combustion engine. Silencer performance is required in a low rotation range, and output improvement is required in a high rotation range. In order to meet these requirements, a valve was installed that opens the exhaust passage when the exhaust pressure rises. When this valve opens, the cross-sectional area of the passage through which the exhaust gas flows increases, improving output in the high-rpm range. There has been proposed a muffler that has a flattened shape (see, for example, Patent Document 1).

However, since high-temperature exhaust gas flows around the coil spring that biases the valve body of the valve that opens due to the increase in exhaust pressure in the closing direction, there is a risk that the coil spring will deteriorate due to heat and the biasing force will decrease.

In order to prevent deterioration of the coil spring due to heat, it has been proposed to dispose the coil spring in a resonance chamber through which exhaust gas does not pass (see Patent Document 2).

Patent No. 4252869 Special Table No. 2013-543953

However, even in the silencer described in Patent Document 2, since a hole serving as an entrance to the resonance chamber is formed upstream of the resonance chamber in which the coil spring is provided, exhaust gas flows into the resonance chamber due to dynamic pressure, There is a problem that the temperature inside the resonance chamber rises.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to propose a silencer that is provided with an urging member such as a coil spring and suppresses temperature rise in the resonance chamber more than the silencer disclosed in Patent Document 2 above.

In order to solve the above problems, a housing is provided in which a resonance chamber, an upstream silencer chamber adjacent to the resonance chamber, and a downstream silencer chamber are formed,
providing a first exhaust passage arranged to penetrate the resonance chamber;
A valve body that rotates around a rotation shaft is provided in the first exhaust passage, and a biasing portion that biases the valve body in a closing direction is provided in the resonance chamber,
The resonance chamber is characterized in that it opens only to the downstream silencer chamber.

Also, the entrance of the resonance chamber may be formed by a neck having a predetermined length and diameter.

Further, a plurality of inlets may be formed in the resonance chamber.

Further, the upstream muffling chamber may be an extension chamber.

Further, a second exhaust passage may be provided, one end of which opens into the downstream silencer chamber, and the other end of the second exhaust passage may open into the upstream silencer chamber or the first exhaust passage. .

The muffler of the present invention is provided with a first exhaust passage extending through the resonance chamber, a valve body for opening and closing the first exhaust passage, and an urging portion for urging the valve body in a closing direction. Since the resonance chamber is provided in the resonance chamber and is open to the downstream silencer chamber, it is difficult for fluid such as exhaust gas to flow into the resonance chamber, thereby suppressing the inside of the resonance chamber from becoming hot. It is possible to suppress the deterioration of the urging portion provided in the body due to exposure to high heat.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a part of a silencer according to Embodiment 1 of the present invention; CC line sectional view of FIG. The cross-sectional view which made the cross section a part of silencer which concerns on Example 2 of this invention. 4 is an example of a cross-sectional view taken along line DD of FIG. 3; Another example of the cross-sectional view taken along the line DD of FIG. The cross-sectional view which made the cross section a part of silencer based on Example 3 of this invention. An example of the cross-sectional view which made the cross section a part of the silencer which concerns on Example 4 of this invention. An example of a cross-sectional view taken along line EE of FIG. An example of the cross-sectional view which made the cross section a part of the silencer which concerns on Example 5 of this invention. Another example of a cross-sectional view of a part of the silencer according to the fifth embodiment of the present invention.

A mode for carrying out the present invention will be described based on an embodiment shown in the drawings.

[Example 1]
FIG. 1 shows a cross-sectional view of a part of a silencer 1 according to Example 1 of the present invention.

As shown in FIGS. 1 and 2, the muffler 1 has a cylindrical housing 2 open at both ends. A diameter-reduced portion 2a is formed at the end portion of the housing 2 on the upstream side A, and a cylindrical introduction opening portion 2b is formed at the upstream side A end thereof. A diameter-reduced portion 2c whose diameter decreases toward the downstream side is formed at the downstream B end of the housing 2, and a cylindrical lead-out opening 2d is formed at the downstream B end. An upstream pipe (not shown) of an exhaust pipe is connected to the introduction opening 2b, and a downstream pipe (not shown) is connected to the outlet opening 2d, so that the exhaust pipe is mounted on the vehicle.

The interior of the housing 2 is partitioned by separators 3 and 4, which are two partitioning members, to form three muffling chambers 5, 6 and 7. In this embodiment, these muffling chambers 5, 6 and 7 are separated from the upstream side. A first expansion chamber 5, a resonance chamber 6, and a second expansion chamber 7 are arranged in order from the downstream side. Thus, at least an upstream silencer chamber adjacent to the resonance chamber 6 is formed upstream of the resonance chamber 6 and a downstream silencer chamber adjacent to the resonance chamber 6 is formed downstream of the resonance chamber 6 .

Separators 3 and 4 are formed with first insertion holes 3a and 4a and second insertion holes 3b and 4b, respectively. The separator 4 is formed with a neck portion 8 forming an inlet of the resonance chamber 6 so as to protrude downstream. The neck portion 8 is formed in a cylindrical shape having a predetermined length and diameter. Only through the neck portion 8, the resonance chamber 6 and the second expansion chamber 7 are communicated, and the first expansion chamber 5 and the resonance chamber 6 are not directly communicated. .

A cylindrical first exhaust passage 10 is fitted through the first insertion holes 3a, 4a and the lead-out opening 2d of the separators 3, 4, and the downstream end of the first exhaust passage 10 (the first exhaust passage 10 in the axial direction) opens to the outside of the muffler 1, and the upstream end of the first exhaust passage 10 (the other end in the axial direction of the first exhaust passage 10) extends into the first expansion chamber 5. Located and open. The first exhaust passage 10 is arranged to pass through the resonance chamber 6 from the upstream side to the downstream side, and the inside of the first exhaust passage 10 and the inside of the resonance chamber 6 are not in direct communication.

A cylindrical second exhaust passage 11 is fitted through the second insertion holes 3b and 4b of the separators 3 and 4 so as to pass through the resonance chamber 6 from the upstream side to the downstream side. The upstream end of the second exhaust passage 11 is located in the first expansion chamber 5, which is an upstream silencer chamber adjacent to the upstream side of the resonance chamber 6, and opens. It is located in a second expansion chamber 7 which is a downstream silencer chamber adjacent to the downstream side of the resonance chamber 6 and is open.

A valve body 13 for opening and closing the first exhaust passage 10 is provided in the first exhaust passage 10 so as to be rotatable (openable and closable) around a rotating shaft 13a. The valve body 13 is constantly urged in the closing direction by an urging member 14 such as a coil spring. When the exhaust pressure in the first exhaust passage 10 reaches or exceeds a predetermined value, the exhaust pressure resists the biasing force of the biasing portion 14 to open the valve body 13 .

As shown in FIG. 1, the rotating shaft 13a and the biasing portion 14 are provided in the resonance chamber 6, and the rotating shaft 13a of the valve body 13 and the biasing portion 14 are located upstream of the neck portion 8. are arranged as follows.

As described above, the resonance chamber 6 is opened only at the neck portion 8, which is the entrance located downstream of the rotation shaft 13a of the valve body 13, and is not formed upstream of the rotation shaft 13a of the valve body 13. do not have. That is, the resonance chamber 6 opens into the second expansion chamber 7, which is the downstream silencer chamber adjacent to the resonance chamber 6 on the downstream side.

A plurality of communication holes 10a are formed in the downstream portion of the first exhaust passage 10, and the interior of the first exhaust passage 10 and the interior of the second expansion chamber 7 are communicated with each other through the communication holes 10a.

Due to the structure described above, the first expansion chamber 5, which is the upstream silencer chamber, and the second expansion chamber 7, which is the downstream silencer chamber, communicate with each other through the first exhaust passage 10 and the second exhaust passage 11. .

When the rotational speed of the internal combustion engine is low, the valve body 13 is biased in the closing direction by the biasing portion 14 to close the first exhaust passage 10 as shown in FIG. Fluid such as exhaust gas (hereinafter simply referred to as exhaust gas) that has flowed into the first expansion chamber 5 from the introduction opening 2b flows into the second expansion chamber 7 after passing through the second exhaust passage 11, It is discharged from the lead-out opening 2d through the communication hole 10a and the first exhaust passage 10, thereby improving the noise reduction performance.

From this state, when the rotational speed of the internal combustion engine increases and the pressure of the exhaust gas in the first exhaust passage 10 reaches or exceeds a predetermined value, the valve element 13 opens against the biasing force of the biasing portion 14. . In this valve open state, the exhaust gas that has flowed into the first expansion chamber 5 from the inlet opening 2b passes through the first exhaust passage 10 and the second exhaust passage 11 and is discharged from the outlet opening 2d. , and the increase in back pressure can be suppressed.

Since the resonance chamber 6 communicates with the second expansion chamber 7, which is a downstream silencer chamber, only through the neck portion 8 located downstream of the rotating shaft 13a of the valve body 13, pressure difference is unlikely to occur in the resonance chamber 6, and high temperature is reduced. is difficult to flow into the resonance chamber 6 through the neck portion 8, and the flow of the exhaust gas into the resonance chamber 6 can be suppressed due to the dynamic pressure. It is possible to prevent the coil spring, which is the urging portion 14 provided in the chamber 6, from being exposed to high heat, thereby suppressing heat deterioration of the coil spring.

[Example 2]
In the first embodiment, the cylindrical neck portion 8 is used to form the entrance of the resonance chamber 6 and communicate the resonance chamber 6 with the second expansion chamber 7. However, as shown in FIGS. As shown, the communication hole 20 formed to penetrate the front and back of the separator 4 may serve as the inlet of the resonance chamber 6 and may communicate the resonance chamber 6 with the second expansion chamber 7 . The communication hole 20 is located downstream of the rotation shaft 13a of the valve body 13, as in the first embodiment, and the resonance chamber 6 and the second expansion chamber 7 are communicated with each other only through the communication hole 20. FIG.

One communication hole 20 may be provided as shown in FIG. 4, or a plurality of communication holes may be provided as shown in FIG.

Since other structures are the same as those of the first embodiment, description thereof is omitted.

The same effects as those of the first embodiment are also obtained in the second embodiment.

[Example 3]
In Embodiments 1 and 2, the downstream end of the first exhaust passage 10 (one end of the first exhaust passage 10 in the axial direction) is opened to the outside of the silencer 1, but as shown in FIG. Alternatively, one axial end of the first exhaust passage 10 may be positioned inside the second expansion chamber 7 and open into the second expansion chamber 7 .

Since other structures are the same as those of the first and second embodiments, description thereof is omitted.

Also in the third embodiment, the same effect as in the first and second embodiments can be obtained.

[Example 4]
In the first to third embodiments, the three silencer chambers 5, 6, and 7 provided in the housing 2 are arranged in this order from the upstream side to the downstream side, the first expansion chamber 5 adjacent to the upstream side of the resonance chamber 6, the resonance Although the chamber 6 and the second expansion chamber 7 adjacent to the downstream side of the resonance chamber 6 are configured, as shown in FIG. The muffler 31 may be configured to be the expansion chamber 32 , the second resonance chamber 33 , and the first resonance chamber 34 , which is the downstream side silencing chamber adjacent to the downstream side of the second resonance chamber 33 .

The first exhaust passage 35 is disposed so as to penetrate and fit in the first insertion holes 3a, 4a of the separators 3, 4 and the lead-out opening 2d. 35) is open to the outside of the muffler 31, and the upstream end of the first exhaust passage 35 (the other end of the first exhaust passage 35 in the axial direction) is an expansion chamber serving as an upstream silencer. 32 is open. The first exhaust passage 35 is disposed so as to pass through the first resonance chamber 34 and the second resonance chamber 33 from the upstream side to the downstream side. 33 is not directly connected.

A valve body 36 that rotates around a rotation shaft 36a is provided in the first exhaust passage 35 . The valve body 36 is always biased in the closing direction by a biasing portion 14 such as a coil spring. When the exhaust pressure in the first exhaust passage 35 reaches or exceeds a predetermined value, the exhaust pressure resists the biasing force of the biasing portion 14 and the valve body 36 opens. Even when the valve body 36 is closed, the communication hole 36b allows communication between the upstream side and the downstream side of the rotating shaft 36a, so that the first exhaust passage 35 is not completely closed by the valve body 36.

A cylindrical communication pipe 37 is fitted through the second insertion holes 3b and 4b of the separators 3 and 4, and is arranged to pass through the second resonance chamber 33 from the upstream side to the downstream side. The upstream end of the communicating pipe 37 opens into the expansion chamber 32, which is the upstream muffling chamber, and the downstream end of the communicating pipe 37 opens into the first resonance chamber 34, which is the downstream muffling chamber.

As in the first and second embodiments, the separator 4 is formed with a neck portion 8 or a communication hole 20 that constitutes the entrance of the second resonance chamber 33 . The second resonance chamber 33 and the first resonance chamber 34 are communicated only through the neck portion 8 or the communication hole 20, and the extension chamber 32 and the second resonance chamber 33 are not directly communicated.

As shown in FIG. 7, the rotating shaft 36a and the biasing portion 14 are provided in the second resonance chamber 33, and the rotating shaft 36a of the valve body 36 and the biasing portion 14 are located at the entrance of the neck portion 8. Alternatively, it is arranged upstream of the communication hole 20 .

As described above, the second resonance chamber 33 is opened only at the neck portion 8 or the communication hole 20, which is an inlet positioned downstream from the rotation shaft 36a of the valve body 36, and is located upstream from the rotation shaft 36a of the valve body 36. has no opening.

With the above structure, the extension chamber 32, which is an upstream silencer chamber adjacent to the upstream side of the second resonance chamber 33, and the first resonance chamber, which is a downstream silencer chamber adjacent to the downstream side of the second resonance chamber 33 The chamber 34 communicates with the communication pipe 37 .

With the above configuration, when the number of revolutions of the internal combustion engine is low, the valve body 36 is biased in the closing direction by the biasing portion 14 to close the valve body 36, and only the communication hole 36b is open. Exhaust gas that has flowed into the expansion chamber 32 through the introduction opening 2b passes through the communication hole 36b in the first exhaust passage 35, and is then discharged through the outlet opening 2d.

From this state, when the rotational speed of the internal combustion engine increases and the pressure of the exhaust gas in the first exhaust passage 35 reaches or exceeds a predetermined value, the valve body 36 opens against the biasing force of the biasing portion 14 . , the flow cross-sectional area is increased, and an increase in back pressure can be suppressed.

The second resonance chamber 33 provided with the urging portion 14 communicates with the first resonance chamber 34 only through the neck portion 8 or the communication hole 20 located downstream of the rotating shaft 36a of the valve body 36. Therefore, the second resonance chamber 33 high-temperature exhaust gas is less likely to flow into the second resonance chamber 33 through the neck portion 8 or the communication hole 20, and the exhaust gas flows into the second resonance chamber 33 due to dynamic pressure. can be suppressed, the inside of the second resonance chamber 33 can be suppressed from becoming high temperature, and the coil spring, which is the biasing portion 14 provided inside the second resonance chamber 33, can be suppressed from being exposed to high heat. Deterioration can be suppressed.

Other structures are the same as those of Examples 1 to 3, so description thereof will be omitted.

Also in the present embodiment 4, the same effects as in the above-described embodiments 1 to 3 can be obtained.

[Example 5]
The structure and configuration of the mufflers 1 and 31 can be any structure and configuration other than those described in the first to fourth embodiments, and the configuration and arrangement of the flow paths provided in the mufflers are also arbitrary. can be set to The number of muffling chambers formed in the mufflers 1 and 31 is three or more, and the number of expansion chambers and the number of resonance chambers are each set to be one or more. can do.

For example, as shown in FIG. 9, the muffler 40 has a first expansion chamber 5, which is an upstream muffling chamber, a resonance chamber 6, and a downstream muffling chamber, like the mufflers 1 of Examples 1 to 3. It has a second expansion chamber 7 , an introduction passage 41 is arranged to pass through the resonance chamber 6 , and the downstream end of the introduction passage 41 opens into the second expansion chamber 7 . Further, the inside of the first expansion chamber 5 and the inside of the introduction passage 41 communicate with each other through a communication hole 41 a formed in the introduction passage 41 .

The first exhaust passage 42 has the rotary shaft 13a of the valve body 13 and the biasing portion 14 similar to those of the first embodiment, the upstream end opens into the first expansion chamber 5, and the downstream end opens into the first expansion chamber 5. It opens outside the muffler 40 . The biasing portion 14 is positioned inside the resonance chamber 6 as in the first and second embodiments.

One end of the second exhaust passage 43 in the axial direction opens into the second expansion chamber 7 which is a silencer chamber provided downstream of the resonance chamber 6, and the other end in the axial direction opens into the first exhaust passage. The passage 42 opens and communicates with the first exhaust passage 42 on the downstream side of the rotating shaft 13 a of the valve body 13 .

As in the first and second embodiments, the resonance chamber 6 communicates with the second expansion chamber 7 only through the neck portion 8 or the communication hole 20 located downstream of the rotation shaft 13a of the valve body.

For example, as shown in FIG. 10, a muffler 51 has a housing 50, and the interior of the housing 50 is partitioned by separators 52, 53, and 54 to form four muffling chambers. The four silencing chambers are, from the left in FIG. It is configured to be a second expansion chamber 7 which is a downstream silencer chamber adjacent to the downstream side of the resonance chamber 6 .

As shown in FIG. 10, the housing 50 is formed with an introduction opening 60 communicating with the first expansion chamber 5 and a discharge opening 61 communicating with the second expansion chamber 7 .

The interiors of the first expansion chamber 5, the first resonance chamber 6, and the second expansion chamber 7 are configured in the same manner as in the first embodiment. 13, a rotating shaft 13a, and a biasing portion 14 are provided.

Further, the separator 54 is formed with a neck portion 8 and a communication hole 20 similar to those of the first to third embodiments.

The second resonance chamber 55 communicates with the first expansion chamber 5 through the neck 63 .

Other structures are the same as those of Examples 1 to 4, so description thereof will be omitted.

The fifth embodiment has the same effect as the first to fourth embodiments.

1, 31, 40, 51 muffler 2 housing 5 first expansion chamber (upstream muffling chamber)
6 resonance chamber 7 second expansion chamber (downstream silencer chamber)
8 neck (entrance of resonance chamber)
20 Communication hole (entrance of resonance chamber)
Reference Signs List 10, 35, 42 first exhaust passage 11, 43 second exhaust passage 13, 36 valve body 13a, 36a valve body rotation shaft 14 biasing portion 32 expansion chamber (upstream silencer chamber)
33 Second resonance chamber (resonance chamber)
34 First resonance chamber (downstream silencer chamber)

Claims (5)

having a housing in which a resonance chamber and an upstream silencer chamber and a downstream silencer chamber adjacent to the resonance chamber are formed;
providing a first exhaust passage arranged to penetrate the resonance chamber;
A valve body that rotates around a rotation shaft is provided in the first exhaust passage, and a biasing portion that biases the valve body in a closing direction is provided in the resonance chamber,
A muffler, wherein the resonance chamber opens only to the downstream muffling chamber. 2. A muffler according to claim 1, wherein the entrance of said resonance chamber is formed by a neck having a predetermined length and diameter. 3. The muffler according to claim 1, wherein a plurality of entrances of said resonance chamber are formed. The muffler according to any one of claims 1 to 3, wherein the upstream muffling chamber is an expansion chamber. A second exhaust passage having one end opened into the downstream silencer chamber is provided, and the other end of the second exhaust passage opens into the upstream silencer chamber or the first exhaust passage. The muffler according to any one of claims 1 to 4.

Images