JPH0614428U - Active silencer - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to an active silencer in which the noise of exhaust gas is positively silenced by a secondary sound source. The purpose is to reduce. A muffler body 41 is partitioned by a partition wall 43 to form a muffler chamber 45, and an exhaust pipe 49 that circulates exhaust gas is inserted into the muffler chamber 45 to form an opening 53 formed in the partition wall 43. In the active silencer in which the secondary sound source 55 is arranged, the cooling pipe 65 that circulates the external air in the axial direction of the silencer body 41 is inserted, and the downstream end of the cooling pipe 65 is connected to the exhaust gas. The tail pipe portion 71 of the pipe 49 or the exhaust pipe 49 is communicated with an outer cylinder 73 which is arranged so as to surround the tail pipe portion 71.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an active silencer in which exhaust noise is positively silenced by a secondary sound source.

[0002]

[Prior art]

 Conventionally, as an active silencer that positively silences the noise of exhaust gas by a secondary sound source, for example, the one disclosed in Japanese Patent Publication No. 58-501292 is known.

FIG. 8 and FIG. 9 show an active silencer of this type. In the drawings, reference numeral 11 denotes a silencer body having a rectangular cross section. The muffler body 11 is divided into three parts by a partition wall 13 arranged at a predetermined interval, a muffling room 15 is formed in the center, and speaker rooms 17 are formed on both sides of the muffling room 15.

An exhaust pipe 19 that circulates the exhaust gas G is inserted into the muffler chamber 15. The exhaust pipe 19 has a large number of small exhaust pipes in a portion located inside the muffler chamber 15. The hole 21 is formed.

An opening 23 is formed in the pair of partition walls 13 at a position facing each other around the exhaust pipe 19, and a speaker 25 as a secondary sound source is arranged in the opening 23. A protective plate 27 for protecting the speaker 25 is arranged in the opening 23 of the partition wall 13, and a large number of small holes 29 are formed in the protective plate 27.

A sound absorbing material 31 made of, for example, glass wool is housed in the muffling room 15 and the speaker room 17. In addition, a microphone 33 is arranged in the muffling chamber 15.

In such an active silencer, the noise of the exhaust gas G is detected by the microphone 33, and a erasing sound having a phase opposite to the detected noise is radiated from the speaker 25, so that the so-called active muffling is performed. Is done.

[0008]

[Problems to be solved by the device]

 However, in such a conventional active silencer, since the speaker 25 is arranged relatively close to the exhaust pipe 19 that circulates the high-temperature exhaust gas, the high-temperature exhaust gas directly or exhausts the exhaust gas. There is a problem that a large heat load is indirectly applied to the speaker 25 by the radiant heat of the gas and the life of the speaker 25 is shortened.

On the other hand, by increasing the heat resistant design value of the speaker 25, the life can be increased, but there is a problem that the increase in the heat resistant design value is also limited. The present invention has been made to solve such a conventional problem, and an object thereof is to provide an active silencer capable of significantly reducing the heat load acting on the secondary sound source as compared with the conventional silencer.

[0010]

[Means for Solving the Problems]

 In the active silencer of the present invention, the silencer body is partitioned by a partition wall to form a muffler chamber, and an exhaust pipe that circulates exhaust gas is inserted into this muffler chamber, and an opening formed in the partition wall In an active silencer with a next sound source, insert a cooling pipe that circulates external air in the axial direction of the silencer body, and connect the downstream end of this cooling pipe to the exhaust pipe or the exhaust pipe. It is connected to the inside of an outer cylinder that surrounds the tail pipe section.

[0011]

[Action]

 In the active silencer of the present invention, the heat of the exhaust gas is heat-exchanged with the air flowing through the cooling pipe to absorb heat. Since the downstream end of the cooling pipe is communicated with the exhaust pipe or the outer cylinder that surrounds the tail pipe part of the exhaust pipe, the ejector effect of the exhaust gas flow causes the air in the cooling pipe to flow downstream. It is sucked toward the side and external air effectively flows into the cooling pipe.

[0012]

【Example】

 Hereinafter, the details of the present invention will be described with reference to the embodiments shown in the drawings. 1 and 2 show a first embodiment of an active silencer of the present invention, in which the reference numeral 41 designates a silencer body having a rectangular cross section.

The muffler body 41 is divided into three by a pair of partition walls 43 arranged at a predetermined interval, a muffling chamber 45 is formed in the center, and speaker chambers 47 are formed on both sides of the muffling chamber 45. ing.

An exhaust pipe 49 that circulates the exhaust gas G is inserted into the muffling chamber 45, and a large number of small holes 51 are formed in the exhaust pipe 49. An opening 53 is formed in the pair of partition walls 43 at a position facing each other around the exhaust pipe 49. In this embodiment, the center of the opening 53 is located at the downstream end of the silencer body 41. It is located at a distance of 1/3 of the total length of the silencer body 41.

A speaker 55, which is a secondary sound source, such as a round speaker, is arranged in the opening 53. A protective plate 57 for protecting the speaker 55 is arranged in the opening 53 of the partition wall 43, and a large number of small holes 59 are formed in the protective plate 57.

A sound absorbing material 61 made of, for example, glass wool is housed in the muffling room 45 and the speaker room 47. A microphone 63 is arranged in the muffling chamber 45.

In this embodiment, however, a large number of cooling pipes 65 are arranged in the muffler chamber 45 in the axial direction of the muffler body 41 to circulate the external air. That is, in this embodiment, a large number of cooling pipes 65 are arranged so as to surround the exhaust pipe 49.

A large number of through holes are formed in the end plates 67, 69 of the silencer body 41 at positions corresponding to the cooling pipes 65, and the upper and lower ends of the cooling pipes 65 are formed in these through holes. Inserted and fixed.

The cooling pipe 65 is formed of, for example, a tube made of a metal having a heat resistance of 300 ° C. or higher and a good thermal conductivity. On the other hand, on the outside of the tail pipe portion 71 of the exhaust pipe 49, an outer cylinder 73 is arranged surrounding the tail pipe portion 71, and the outer cylinder 73 is fixed to the end plate 69 by welding or the like. There is.

The downstream ends of a large number of cooling pipes 65 are opened in the space between the outer cylinder 73 and the tail pipe portion 71. Further, the downstream end of the outer cylinder 73 is located so as to project downstream from the tail pipe portion 71.

In the above-described active silencer, the noise of the exhaust gas G is detected by the microphone 63, and the elimination sound having a phase opposite to that of the noise is emitted from the speaker 55, so that the so-called active silencer is performed. .

On the other hand, the outside air in front of the silencer body 41 flows into the cooling pipe 65 from the front end opening of the cooling pipe 65, exchanges heat with the heat of the exhaust gas through the cooling pipe 65, and then the exhaust pipe 49. The exhaust gas is sucked by the ejector effect due to the outflow of the exhaust gas from the end of the tail pipe portion 71, and flows out into the atmosphere from the downstream end of the outer cylinder 73.

Therefore, in the above-described active silencer, the cooling pipe 65 that circulates the external air in the axial direction of the silencer body 41 is inserted, and the downstream end of the cooling pipe 65 is connected to the tail of the exhaust pipe 49. Since the pipe 71 is communicated with the outer cylinder 73 surrounding the pipe part 71, the air in the cooling pipe 65 is sucked toward the downstream side by the ejector effect due to the flow of the exhaust gas, and the outside air is cooled by the cooling pipe 65. Since it effectively flows into the inside, heat exchange between the heat of the exhaust gas and the air flowing through the cooling pipe 65 is efficiently performed, and the heat load acting on the speaker 55 can be significantly reduced as compared with the conventional case.

That is, since the radiant heat of the exhaust gas flowing through the exhaust pipe 49 is effectively absorbed by the cooling pipe 65, it is possible to reliably reduce the intrusion of heat into the vibrating surface of the speaker 55, and the speaker 55. The heat load acting on is greatly reduced as compared with the conventional one, and thereby, the heat resistant design value of the speaker 55 can be made significantly lower than the conventional one.

Further, since the temperature of the muffling chamber 45 becomes low, the transmission loss of the radiated sound from the speaker 55 or the transmission loss of the acoustic wave to the speaker 55 is reduced, and a good silencing characteristic can be obtained. become.

Further, since the front end of the cooling pipe 65 opens to the front side of the muffler main body 41, the vehicle speed air can easily flow into the cooling pipe 65. FIG. 3 shows a second embodiment of the active silencer of the present invention. In this embodiment, a reduced diameter portion 75 is formed at the downstream end of the outer cylinder 73A.

Also in this active silencer, substantially the same effect as that of the first embodiment can be obtained, but in this embodiment, since the reduced diameter portion 75 is formed at the downstream end of the outer cylinder 73A. , The ejector effect can be further enhanced.

FIG. 4 shows a third embodiment of the active silencer of the present invention. In this embodiment, the tail pipe portion 71A of the exhaust pipe 49 is tapered in diameter toward the downstream side. Has been done.

In this active silencer as well, almost the same effect as in the first embodiment can be obtained, but in this embodiment, the tail pipe portion 71A of the exhaust pipe 49 is tapered toward the downstream side. Since the diameter is expanded to 1, the pressure inside the silencer body 41 can be adjusted.

FIG. 5 shows a fourth embodiment of the active silencer of the present invention. In this embodiment, the downstream end of the tail pipe portion 71B is reduced in diameter toward the downstream side. The reduced diameter portion 81 of the inner cylinder 79 is arranged so as to be opposed to the diameter portion 77 with a predetermined interval.

The inner cylinder 79 is fitted and fixed to the downstream end of the outer cylinder 73B. Also in this active silencer, almost the same effect as in the first embodiment can be obtained, but in this embodiment, the ejector effect can be further enhanced.

FIG. 6 shows a fifth embodiment of the active silencer of the present invention. In this embodiment, a cooling pipe 65 is arranged outside the partition wall 43 on the side of the speaker chamber 47 to cool the silencer. As shown in FIG. 8, the tube 65 is disposed by inserting a cylindrical speaker fixing rib 83.

Further, the tail pipe portion 71C is gradually expanded in diameter toward the downstream side, and the respective cooling pipes 65 are separately opened to the tail pipe portion 71C via the connecting pipe portion 85.

In this active silencer as well, almost the same effect as in the first embodiment can be obtained, but in this embodiment, since the cooling pipe 65 is inserted through the speaker fixing rib 83, the speaker fixing It is also possible to lower the temperature of the working rib 83, and the speaker 55 can be cooled more efficiently.

Further, since the cooling pipe 65 is arranged on the front surface of the speaker 55, it is possible to obtain a heat insulating effect on the speaker 55 by the air inside the cooling pipe 65. In the embodiment described above, the fins are formed on the cooling pipe 65, so that the cooling efficiency can be further improved.

[0036]

[Effect of device]

 As described above, in the active silencer of the present invention, the cooling pipe for circulating the external air is inserted in the axial direction of the silencer body, and the downstream end of the cooling pipe is connected to the exhaust pipe or the tail of the exhaust pipe. Since it communicates with the external cylinder that surrounds the pipe, the ejector effect of the exhaust gas flow sucks the air in the cooling pipe toward the downstream side, and the external air effectively flows into the cooling pipe. Therefore, there is an advantage that the heat of the exhaust gas and the air flowing through the cooling pipe are efficiently exchanged with each other, and the heat load acting on the speaker can be significantly reduced as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of an active silencer of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view showing a second embodiment of the active silencer of the present invention.

FIG. 4 is a sectional view showing a third embodiment of the active silencer of the present invention.

FIG. 5 is a sectional view showing a fourth embodiment of the active silencer of the present invention.

FIG. 6 is a sectional view showing a fifth embodiment of the active silencer of the present invention.

7 is a perspective view showing the vicinity of the cooling pipe of FIG.

FIG. 8 is a sectional view showing an example of a conventional active silencer.

9 is a cross-sectional view of FIG.

[Explanation of symbols]

 41 silencer body 43 partition wall 45 silencer chamber 49 exhaust pipe 53 opening 55 speaker (secondary sound source) 65 cooling pipe 71 tail pipe portion 73 outer cylinder

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Creator Yoshihisa Takemori 5-24-15 Minamidai, Nakano-ku, Tokyo Calsonic Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A muffler body (41) is partitioned by a partition wall (43) to form a muffler chamber (45), and an exhaust pipe (49) for circulating exhaust gas is inserted into the muffler chamber (45). An opening (53) formed in the partition wall (43)
In the active silencer in which the secondary sound source (55) is arranged, the cooling pipe (65) for circulating the external air in the axial direction of the silencer body (41) is inserted, and the cooling pipe (6
The downstream side end of 5) is communicated with the exhaust pipe (49) or an outer cylinder (73) arranged so as to surround the tail pipe portion (71) of the exhaust pipe (49). Active silencer.