JP2002235522A - Muffler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a muffler capable of providing a sufficient silencing effect of exhaust sounds including sounds in a specific frequency region such as about 100 Hz. SOLUTION: This muffler 10 comprises one resonance chamber 2D that does not pass exhaust gas and three or more silencing chambers 2A to 2C for passing the exhaust gas. An exhaust gas introduction port 6A is disposed in the most upstream silencing chamber 2A, and an exhaust gas flow outlet 7A is disposed in the most downstream silencing chamber 2C. The outer periphery of a communicating pipe 8 that has partitions 8C at both ends and passes the exhaust gas through the plurality of silencing chambers is provided with many communication holes 8A1 corresponding to the communicated silencing chambers, and one silencing chamber 2A is communicated with the resonance chamber 2D through a resonance pipe 9. Thus, the exhaust gas is repeatedly narrowed and expanded between the communication holes of the communicating pipe and the silencing chambers to lose pressure, and the sounds in the specific frequency region are eliminated in the resonance chamber, so that the sufficient silencing effect of the exhaust sounds can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust muffler for an internal combustion engine used in construction machines and other machines.

[0002]

BACKGROUND ART In internal combustion engines used in construction machines, etc.,
An exhaust muffler called a muffler is connected to the exhaust pipe to reduce exhaust noise from the combustion chamber. This exhaust silencer has conventionally had various structures.
As a conventional example of an exhaust silencer used in an internal combustion engine for a construction machine, there is known an exhaust silencer that repeatedly reduces and expands exhaust gas to muffle the noise (Japanese Patent Application Laid-Open No. 2000-227019).

[0003] In the structure of the above-mentioned conventional exhaust silencer, three silence chambers are provided inside a drum-shaped main body, and an exhaust gas inlet is provided in a silence chamber at the most upstream, and an exhaust gas outlet is provided in a silence chamber at the most downstream. , Respectively. In addition, communication pipes are provided for communicating between adjacent chambers of each muffler chamber, and these communication pipes are provided with partition walls at both ends and have predetermined positions on the outer periphery corresponding to the muffler chamber to be communicated with. In addition, a large number of communication holes for communicating exhaust gas are formed. In the exhaust silencer having such a configuration, the exhaust gas is expanded and sent from the exhaust gas inlet to the most upstream silencer, and reaches the exhaust gas outlet from the most upstream silencer via the most downstream silencer. Until this time, the expansion and contraction are repeated by the communication hole of the communication pipe and the silencing chamber, so that the pressure is lost and the sound is silenced.

[0004]

However, the conventional exhaust silencer has a structure in which pressure is lost and silence is caused by repeating throttling and expansion between the communication hole of the communication pipe and the silencer. However, this structure has a problem that it is difficult to suppress a sound in a specific frequency range of, for example, about 100 Hz, such as a primary combustion sound.

It is an object of the present invention to provide an exhaust silencer capable of obtaining a sufficient silencing effect of exhaust noise including a sound in a specific frequency range of, for example, about 100 Hz.

[0006]

Means for Solving the Problems and Functions and Effects The applicant of the present invention has thoroughly studied the basic principle of noise reduction measures and has made a rational design. The exhaust noise reduction apparatus of the present invention has the following configuration. This aims to achieve the above object. That is, the invention according to claim 1 is an exhaust silencer connected to an exhaust pipe of an internal combustion engine, wherein at least one resonance chamber in which exhaust gas of the internal combustion engine does not substantially flow, and the exhaust gas is provided. An exhaust gas inlet for directly flowing the exhaust gas into the most upstream muffler chamber of the muffler chambers. An exhaust gas outlet for allowing gas to flow out is provided, and a communication pipe for allowing the exhaust gas to flow between the plurality of muffling chambers is provided, and a substantially hermetic partition is provided at both ends of the communication pipe, At a predetermined position on the outer periphery of the communication pipe, a large number of communication holes corresponding to the silencing chamber to be communicated are provided, and that any one of the silencing chambers and the resonance chamber are communicated with the resonance pipe. Feature It is a gas silencer.

According to the present invention, the exhaust gas generated in the internal combustion engine is first flowed directly into the exhaust gas inlet, fed into the uppermost muffler and expanded.
Exhaust sound is attenuated. Predetermined spaces of three or more muffling chambers including the most upstream muffling chamber are communicated by communication pipes, and since the communication pipes are provided with partition walls at both ends and provided with a large number of communication holes on the outer periphery, The exhaust gas sent to the uppermost silencing chamber is sent from the radial direction into the inside of the communication pipe while being throttled by the communication hole, and then moves in the communication pipe in the axial direction, and is further throttled by the communication hole. It is enlarged and sent to the next sound deadening room. Further, the exhaust gas is sent from this silencing chamber to the next silencing chamber, and finally to the silencing chamber on the most downstream side, through the communication pipe, and is discharged to the outside from the exhaust gas outlet.

When exhaust gas is sent from the most upstream silencing chamber to the silencing chamber on the downstream side, the exhaust gas is repeatedly throttled and expanded between the communication hole of the communicating pipe and the silencing chamber, and the pressure is reduced. Energy is attenuated by being lost and changing the flow in the axial direction and the radial direction, so that the exhaust noise of the exhaust gas can be suppressed. In addition, a resonance chamber was provided, and the resonance chamber was connected to one of the muffling chambers through a resonance pipe.
A sound in a specific frequency range, for example, about 100 Hz, such as a secondary sound, is extinguished in the resonance tube and the resonance chamber, whereby a sufficient noise-elimination effect of exhaust noise including a sound in a specific frequency range can be obtained. .

In the first aspect of the present invention, the substantially sealed partition walls at both ends of the communication pipe are not limited to completely sealed ones, and the flow of exhaust gas from the communication hole on the outer circumference of the communication pipe is not limited to the completely sealed one. Including those capable of substantially flowing out, for example, those in which a communicating portion such as a small hole is formed in a partition wall may be used.

According to a second aspect of the present invention, in the exhaust muffler according to the first aspect, the communication pipe is constituted by a single pipe. According to the present invention, since the communication pipe is composed of one pipe, the resonance pipe can be easily provided on the outer periphery thereof, so that the structure is simplified, and as a result, a compact exhaust silencer can be obtained.

According to a third aspect of the present invention, in the exhaust muffler according to the first or second aspect, a partition is provided at both ends and a main body having the muffling chamber and the resonance chamber provided therein. The communication tube is arranged so that the axis is substantially aligned with the axis of the main body, and the resonance tube is arranged around the communication tube. In the present invention, since the communication pipe is arranged with the axis aligned with the axis of the main body, the degree of freedom in arranging the resonance pipe around the communication pipe is increased, and as a result, the resonance pipe is optimized for resonance. It can be provided at a position where a frequency can be obtained.

According to a fourth aspect of the present invention, in the exhaust silencer according to any one of the first to third aspects, a cross-sectional area of the communication pipe is 5 to 30% of a cross-sectional area of the silencer. It is characterized by the following. In the present invention,
By setting the cross-sectional area of the communication pipe to 5 to 30% of the cross-sectional area of the silencing chamber, the volume on the silencing chamber side can be increased, and the flow of the exhaust gas can be effectively reduced and expanded. As a result, a high silencing effect can be obtained. Further, since the volume on the muffler chamber side can be increased, the volume of the muffler chamber does not need to be increased in order to provide the resonance tube. Therefore, even when the resonance tube is provided, the apparatus can be made compact.

According to a fifth aspect of the present invention, in the exhaust muffler according to any one of the first to fourth aspects, a smooth throttle portion and an enlarged portion are provided in a resonance chamber of the communication pipe. It is characterized by having. In the present invention, since the flow of the exhaust gas is rectified by providing the smooth throttle portion and the enlarged portion, the flow loss of the exhaust gas after the throttle portion and the enlarged portion can be reduced.

According to a sixth aspect of the present invention, in the exhaust silencer according to any one of the first to fifth aspects, a sound absorbing material chamber for receiving a sound absorbing material is provided at a position of the resonance chamber of the communication pipe. The sound absorbing material chamber and the communication pipe are communicated with each other through a number of small holes formed in the communication pipe. According to the present invention, since the exhaust gas sent from the small holes of the communication pipe to the sound absorbing material chamber is absorbed by the sound absorbing material in the sound absorbing material chamber, the sound absorbing effect is improved.

According to a seventh aspect of the present invention, in the exhaust muffler according to any one of the first to sixth aspects, a bypass hole is provided in a partition wall that does not include the resonance chamber among partition walls that partition the muffler chambers. Is provided. In the present invention, since the partition is provided with the bypass hole, the exhaust loss can be reduced without lowering the noise reduction effect, and the fuel efficiency can be reduced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. Here, in each embodiment, the same components are denoted by the same reference numerals, and the description is omitted or simplified. 1 and 2 show a first embodiment of the present invention. The exhaust silencer 10 according to the first embodiment is connected to an exhaust pipe (not shown) of a diesel engine for construction equipment, and has a cylindrical shape whose both ends are closed by an end plate 1, that is, a drum shape. Main body 2.

In the main body 2, first, second, and third muffling chambers 2A, 2B, 2C,
A first partition plate 3A, a second partition plate 3B, a third partition plate 3C, and a first muffler chamber 2A for partitioning into a resonance chamber 2D.
An exhaust gas inlet pipe 6 connected to the exhaust pipe and a tail pipe 7 connected to the third silencing chamber 2C.
And one communication pipe having one end supported by the first partition plate 3A, the intermediate portion supported by the second partition plate 3B, and the other end supported by the third partition plate 3C. 8, a resonance tube 9 attached across the first silencing room 2A and the resonance room 2D.
Are provided.

First partition plate 3A and second partition plate 3B
Are respectively provided with a disk portion 3D and a peripheral edge portion 3E which is provided upright on the peripheral edge of the disk portion 3D and abuts on the inner peripheral surface of the main body 2.
And a first support portion 3F that supports the communication tube 8 at the center of the disk portion 3D, and a second support portion 3G that supports the resonance tube 9 at a position away from the first support portion 3F. I have. The third partition plate 3C includes a disk portion 3D and a peripheral portion 3D.
E and a first support portion 3F.

The peripheral portion 3 of the first and third partition plates 3A and 3C
E (for example, the tail pipe 7 in FIG. 1)
Part) is fixed to the inner peripheral surface of the main body 2 by welding or the like,
The other (in FIG. 1, the exhaust gas introduction pipe 6 side) is press-fitted into the inner peripheral surface of the main body 2 so as to be movable in the axial direction of the main body 2.

The exhaust gas introduction pipe 6 is fixed to the outer peripheral portion of the main body 2 by welding or the like so that the axis thereof is orthogonal to the axial direction of the main body 2, and opens to the first silence chamber 2A on the most upstream side. The end is an exhaust gas inlet 6A through which exhaust gas generated by the diesel engine is introduced via a connection pipe. In FIG. 1, the exhaust gas introduction pipe 6 is drawn on the opposite side of the tail pipe 7 with respect to the axis of the main body 2 (downward in the figure: at a position of 180 degrees). In order to clarify the relationship between the exhaust gas introduction pipe 6 and the first silencing chamber 2A, as shown in FIG. In some cases it has been done.

The tail pipe 7 is fixed to the outer peripheral portion of the main body 2 by welding or the like such that the straight line axis of the tail pipe 7 is orthogonal to the axial direction of the main body 2. The end opening to 2C is an exhaust gas outlet 7A for allowing exhaust gas to flow out.

The communication pipe 8 is formed of a single pipe member as described above, and a partition member 8D is provided inside the communication pipe 8 at the position of the second sound deadening chamber 2B. The partition member 8D functions as a partition for closing the inside of the communication pipe 8. The communication pipe 8 is divided into a first cylindrical portion 8A on the first silencing chamber 2A side and a second cylindrical portion 8B on the third silencing chamber 2C side with the partition member 8D as a boundary. Further, partition walls 8C are provided at both ends of the communication pipe 8. The axis of the communication pipe 8 and the axis of the main body 2 match. Further, the cross-sectional area of the communication pipe 8 is formed so as to be 5 to 30% of the cross-sectional area of the first, second, and third muffling chambers 2A, 2B, and 2C.

On the outer periphery of the communication pipe 8, a large number of communication holes 8A1 are formed at a portion facing the first silencing chamber 2A, and a large number of communication holes 8A2 and 8A3 are formed at a portion facing the second silencing chamber 2B. A communication hole 8A in a portion facing the third sound deadening chamber 2C.
4 are formed in large numbers. The partition member 8D is
It is provided between the communication holes 8A2 and 8A3.
The number and size of the communication holes 8A1 to 8A4 depend on the size of the engine and the exhaust pipe, the length and diameter of the main body 2, the location where the exhaust gas flows in, the location where the exhaust gas flows out, and the like. In consideration of this, it is determined appropriately so that the sound can be muted most efficiently.

The partition 8C is formed in a substantially sealed state. That is, a communication part such as a small hole is formed in the partition wall 8C, and the resistance of the flow of the exhaust gas when the exhaust gas flows in and out from the communication holes 8A1 and 8A4 on the outer periphery of the communication pipe 8 is reduced. It can be reduced. In the case of a substantially sealed state, the first
It is preferable to make the partition 8C disposed in the silencing chamber 2A substantially closed. The partition 8C may have a completely closed structure in which the partition 8C is completely closed.

The first partition plate 3A, the second partition plate 3B, and the third partition plate 3C constitute partition walls, respectively. Among them, the first partition plate 3A does not include the resonance chamber 2D. As shown in FIG. 2, a plurality of small holes 3H and the like are formed in one partition plate 3A, and a pressure loss of the exhaust gas can be prevented by partially bypassing the exhaust gas. I have. At this time, the formation of the small holes 3H does not affect the flow of the exhaust gas from the communication holes 8A1 of the communication pipe 8. Note that the plurality of small holes 3H are also formed in any of the partition plates 3A, 3B, and 3C that do not form the resonance chamber 2D in each of the embodiments described below.

A resonance chamber 2D through which exhaust gas does not flow is provided between the second muffler chamber 2B and the third muffler chamber 2C, and is provided between the resonance chamber 2D and the first muffler chamber 2A. A resonance tube 9 is provided at a position apart from the communication tube 8 in the radial direction of the main body 2 in parallel with the communication tube 8. The resonance pipe 9 is formed of a pipe having an inner diameter smaller than that of the communication pipe 8.

In order to assemble such an exhaust silencer 10, a first partition plate 3 A, in which a communication pipe 8 and a resonance pipe 9 are attached in advance inside the main body 2 with the end plate 1 removed, and a first 2 is inserted into the main body 2, and the first and second sub-assemblies are inserted into the main body 2.
After finely adjusting and positioning the second partition plates 3A and 3B in the axial direction, the third partition plate 3C is assembled. At this time, the first
One of the partition plate 3A and the third partition plate 3C is fixed to the main body 2 by welding or the like, and the other is pressed into the main body 2. Thereafter, both ends of the main body 2 are closed with the end plate 1, an exhaust gas introduction pipe 6 and a tail pipe 7 are attached to the outer peripheral portion of the main body 2, and an exhaust pipe of the diesel engine is connected to the exhaust gas introduction pipe 6.

The operation of the first embodiment will be described. Exhaust gas generated by the diesel engine is sent to an exhaust gas introduction pipe 6 through an exhaust pipe. The exhaust gas sent to the exhaust gas introduction pipe 6 is rapidly expanded and sent into the first silencing chamber 2A located on the most upstream side through the exhaust gas introduction port 6A, so that the pressure is lost and the exhaust noise is reduced. Is turned off, and there is a first silencing effect.

The exhaust gas sent into the first silencing chamber 2A is sent into the communication pipe 8 while being narrowed down by the communication hole 8A1 of the communication pipe 8, and the exhaust gas is reduced in this exhaust gas narrowing step. The exhaust sound of is extinguished. That is, there is a second silencing effect in the process in which the exhaust gas enters the communication pipe 8 from the communication hole 8A1 of the communication pipe 8. Exhaust gas that has flowed into the communication pipe 8 from the radial direction through the communication hole 8A1 is rectified by changing its direction in the axial direction inside the pipe and is stopped by the partition member 8D on the downstream side, and thus flows again through the communication hole 8A2. After the direction is changed to a right angle and the flow is rectified, the air is enlarged and sent to the second silencing chamber 2B.

The exhaust gas is stopped by the partition member 8D, is sent from the communication hole 8A2 to the second muffler chamber 2B, and flows from the second muffler chamber 2B into the communication pipe 8 again through the communication hole 8A3. It is in a state of bypassing the outer periphery of the member 8D, and flows into the communication pipe 8 downstream of the partition member 8D via another muffling chamber (expansion chamber, damping chamber), whereby the sound is also muffled. Further, the communication hole 8A
The exhaust noise of the exhaust gas is also eliminated in the step of narrowing down by 3. Then, inside the communication pipe 8, the direction is changed in the axial direction, rectified and flows downstream, and the third sound deadening chamber 2 is passed through the communication hole 8A4.
By being enlarged and sent to C, the pressure fluctuation of the exhaust gas is reduced, and as a result, the sound is muted. The exhaust gas sent into the third silencing chamber 2C is exhausted from the tail pipe 7 to the outside while the exhaust noise is silenced.

Exhaust gas flowing from the exhaust gas introducing pipe 6 is silenced in the first silencing chamber 2A and flows into the communication pipe 8, but at the same time, primary combustion noise and the like are generated in the resonance pipe 9 and the resonance chamber 2D. As a result, the sound in a specific frequency range of, for example, about 100 Hz is muted, so that the noise in the specific frequency range is reduced.

According to the first embodiment, the following effects can be obtained. (1) In the exhaust silencer 10, the exhaust gas sent from the most upstream silencer 2 </ b> A to the silencers 2 </ b> B and 2 </ b> C on the downstream side communicates with the communication holes 8 </ b> A <b> 1 to 8 </ b> A <b> 4 of the communication pipe 8 and the respective silencers 2 </ b> A and 2 </ b> B.
Between 2C and 2C, throttling and expansion are repeated, pressure is lost, and energy is attenuated by changing the flow in the axial direction and the radial direction of the communication pipe 8, so that exhaust gas is exhausted. Sound can be turned off sufficiently. In addition, resonance room 2
D is provided, and the resonance chamber 2D and the first silencing chamber 2A are communicated with each other by the resonance pipe 9.
The sound of a specific frequency range of about Hz is transmitted through the resonance tube 9 and the resonance chamber 2.
D, thereby providing a sufficient noise-elimination effect for exhaust noise including sound in a specific frequency range.

(2) Since the cross-sectional area of the communication pipe 8 is formed so as to be 5 to 30% of the cross-sectional area of the first, second and third silence chambers 2A, 2B and 2C, the silence chamber is formed. 2A, 2B, 2C
, The exhaust gas flow can be effectively throttled and expanded, and a high noise reduction effect can be obtained. In addition, each of the silencers 2A, 2B, 2
Since the volume of C can be increased, the volume of the silencing chambers 2A, 2B, and 2C does not need to be increased to provide the resonance tube 9, and the device can be made compact even when the resonance tube 9 is provided.

(3) Since the partition walls 8C at both ends of the communication pipe 8 are substantially sealed with small holes, the communication holes 8
It can be used as an aid to A1, and as a result, pressure loss of exhaust gas can be reduced. (4) A plurality of small holes 3H are formed in the first partition plate 3A, which is a partition, and a part of exhaust gas can be bypassed. As a result, the pressure loss of the exhaust gas can be reduced.

(5) Since the communication pipe 8 is provided with the partition member 8D, the exhaust gas flowing out of the communication hole 8A1 on the upstream side of the partition member 8D flows through the communication hole on the downstream side while bypassing the outer periphery of the partition member 8D. 8A2 again flows into the communication pipe 8, so that the partition member 8D allows the second sound deadening chamber 2B to function as if it were two sound deadening chambers, and the sound deadening effect can be more fully exhibited. it can.

(6) In assembling the exhaust muffler 10, first, the communication pipe 8 is supported and fixed to the first and second partition plates 3A and 3B, and the resonance pipe 9 is fixed to the first and second partition plates 3A. 3B, which are supported and fixed to form a part (semi-assembled product), which is attached to the inside of the main body 2, and the first and second partition plates 3A, 3B are finely adjusted in the axial direction with respect to the main body 2. After the positioning, the third partition plate 3C is assembled, so that the assembling work can be performed easily and accurately.

(7) One of the first and third partition plates 3A, 3C is fixed to the main body 2 by welding or the like, and the other is press-fitted, so that the communication pipe 8 expands due to the heat of the exhaust gas. Also, the press-fitted first and third partition plates 3A and 3C relatively move with respect to the main body 2, so that the thermal expansion of the communication pipe 8 can be absorbed.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is different from the first embodiment in that a resonance chamber 2D is arranged between a first silencing chamber 2A and a second silencing chamber 2B.
The third embodiment is different from the first embodiment, and the other basic configuration is the same as that of the first embodiment.

In FIG. 3 showing the overall configuration, an exhaust silencer 20 of the second embodiment includes a drum-shaped main body 2, and a communication pipe 28 is connected to the first, second, and third main bodies. The resonance pipe 29 is supported by the first and second partition plates 3A and 3B and supported by the partition plates 3A, 3B and 3C.

The communication pipe 28 is formed of a single pipe member, and the partition member 8D is provided inside the communication pipe 28 at the position of the second sound deadening chamber 2B. And communication pipe 2
Is divided into a first tubular portion 28A on the first sound deadening chamber 2A side and a second tubular portion 28B on the third sound deadening chamber 2C side with the partition member 8D as a boundary, and further communicates with each other. The partition walls 8C are provided at both ends of the tube 28. In the second embodiment, the resonance chamber 2D is located between the first and second silencing chambers 2A and 2B.
Is provided, the first tubular portion 28A of the communication tube 28 is different from the first tubular portion 2A in comparison with the first embodiment.
It is formed longer than 8B.

At the outer periphery of the communication pipe 28, a first silencing chamber 2A
The communication holes 8A1 are formed in a portion facing the second sound deadening chamber 2B, and the communication holes 8A2 and 8A3 are formed in a portion facing the second sound deadening chamber 2B. Is formed.

The resonance pipe 29 is formed of a pipe thinner than the resonance pipe 9, and as described above, the first silencing chamber 2A and the second
Is provided over the muffler chamber 2B, but a partition wall 29A is provided at the end of the second muffler chamber 2B, and a large number of communication holes 29B are formed on the outer periphery so as to reach the resonance chamber 2D. Therefore, the exhaust gas that has passed through the resonance pipe 29 does not flow into the second silencing chamber 2B because of the presence of the partition wall 29A.

The operation of the second embodiment will be described. In the second embodiment, the exhaust gas sent to the exhaust gas introduction pipe 6 is discharged to the outside from the tail pipe 7 through the communication pipe 28 by the same operation as the first embodiment. At this time, the exhaust gas is sent from the exhaust gas introduction pipe 6 to the inside of the communication pipe 18 via the first silencing chamber 2A, and the communication holes 8A2, 8A3 and the second silencing chamber 2 are located downstream.
After the expansion and contraction at the time of inflow and discharge with B are repeated, the air is expanded from the communication hole 8A4 to the third sound deadening chamber 2C, and is discharged to the outside through the tail pipe 7 therefrom. You.

On the other hand, the exhaust gas flowing from the exhaust gas introduction pipe 6 is supplied to the first silencing chamber 2 as in the first embodiment.
The sound is attenuated by A and flows into the communication pipe 8, but at the same time, the resonance pipe 29 and the resonance chamber 2D, for example, 10
Sound in a specific frequency range of about 0 Hz is muted, thereby reducing noise in a specific frequency range.

According to the above second embodiment, in addition to the effects (1) to (7) of the first embodiment,
The following effects can be obtained. (8) Even if the resonance room 2D is provided next to the first muffling room 2A, the resonance tube 29 bridged between the first muffling room 2A and the third muffling room 2C is connected to the resonance room 2D. Open communication hole 2
Since 9B is formed, there is an effect that there is no restriction on the arrangement position of the resonance chamber 2D.

Next, a third embodiment of the present invention will be described with reference to FIG. The third embodiment is different from the first embodiment in that the first muffler chamber 2A to the third muffler chamber 2C are continuous, and the resonance chamber 2D is arranged outside the third muffler chamber 2C.
Other basic configurations are the same as in the first embodiment. In FIG. 4 showing the overall configuration, an exhaust silencer 30 according to a third embodiment is shown.
Comprises a drum-shaped main body 2, a communication pipe 38 is supported by the first and second partition plates 3A, 3B, and a resonance pipe 39 is provided with first, second, and third Partition plate 3A, 3
B and 3C, respectively.

The communication pipe 38 is formed by a single pipe member, and the partition member 8D is provided inside the communication pipe 38 at the position of the second sound deadening chamber 2B. And communication pipe 2
Is divided into a first cylindrical portion 38A on the first sound deadening chamber 2A side and a second cylindrical portion 38B on the third sound deadening room 2C side with the partition member 8D as a boundary, and further communicates with each other. The partition walls 8C are provided at both ends of the tube 38. In the third embodiment, since the first muffling chamber 2A to the third muffling chamber 2C are continuous, the length of the communication pipe 38 is smaller than the length of the communication pipe 8 of the first and second embodiments. It is formed shorter than 28.

On the outer periphery of the communication pipe 38, a large number of communication holes 8A1 are formed at a portion facing the first sound deadening chamber 2A.
A large number of communication holes 8A2 and 8A3 are formed in a portion facing the muffling room 2B, and a large number of communication holes 8A4 are formed in a portion facing the third muffling room 2C. The resonance tube 39 is formed of a pipe that is thicker than the resonance tube 9 of the first embodiment.
From the muffling room 2A to the resonance room 2D.

The operation of the third embodiment will be described. In the third embodiment, as in the first embodiment, most of the exhaust gas sent to the first silencing chamber 2A while rapidly expanding via the exhaust gas introduction pipe 6 is located on the most upstream side. The air is exhausted from the first silencing chamber 2A through the communication pipe 38 to the tail pipe 7 from the third silencing chamber 2C at the most downstream side. At this time, a throttle at the time of inflow and discharge between each of the muffling chambers 2A, 2B, and 2C and the communication holes 8A1 to 8A4 of the communication pipe 38,
The exhaust noise of the exhaust gas is reduced by the expansion.

On the other hand, the exhaust gas flowing from the exhaust gas introduction pipe 6 cancels a sound in a specific frequency range of, for example, about 100 Hz, such as a primary combustion sound, in the resonance pipe 39 and the resonance chamber 2D. In addition, noise in a specific frequency range is reduced.

According to the third embodiment, the first embodiment
In addition to the effects of (1) to (7), the following effects can be obtained. (9) Since the first muffler chamber 2A to the third muffler chamber 2C are continuous and the resonance chamber 2D is arranged outside the third muffler chamber 2C, the communication pipe 38 can be shortened, and resonance can be achieved. Tube 3
Since the length of 9 is long, the exhaust sound loses a large energy when flowing through the resonance pipe 39, and the sound of a specific frequency range such as a primary sound of combustion, for example, a frequency range of about 100 Hz can be eliminated in the resonance chamber 2D. And a further noise reduction effect can be obtained.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment is different from the third embodiment in that the resonance chamber 2D is provided adjacent to the first silencing chamber 2A, but the basic configuration is the same as the third embodiment. In FIG. 5 showing the overall configuration, an exhaust silencer 4 of a fourth embodiment is shown.
0 includes a drum-shaped main body 2 in which the communication pipe 38 is provided with a second partition plate 3B and a third partition plate 3C.
, The resonance tube 49 includes the first and second partition plates 3A,
3B, each is provided. Resonance tube 4
Reference numeral 9 is provided over the second silencing room 2B and the resonance room 2D.

The operation of the fourth embodiment will be described. In the fourth embodiment, most of the exhaust gas sent to the exhaust gas introduction pipe 6 is transferred from the first muffler chamber 2A located on the most upstream side to the communication pipe 3
8 to the tail pipe 7
Exhausted. At this time, the exhaust noise of the exhaust gas is reduced by the flow of the exhaust gas between the silencing chambers 2A, 2B, and 2C and the communication holes 8A1 to 8A4 of the communication pipe 38.

The exhaust gas flowing from the exhaust gas introducing pipe 6 is supplied to the resonance pipe 49 and the resonance chamber 2 communicating with the second silencing chamber 2B.
With D, noise in a specific frequency range of, for example, about 100 Hz, such as the primary sound of combustion, is extinguished, thereby reducing noise in a specific frequency range.

In the fourth embodiment, (1) to (1) of the first embodiment are used.
In addition to the effect of (7), the following effect can be obtained. (10) Since the resonance chamber 2D is provided adjacent to the first silencing chamber 2A and opposite to the downstream side of the flow, the third silencing chamber 2D is provided.
The length of the resonance tube 49 can be shorter than in the third embodiment in which the resonance chamber 2D is provided adjacent to C and downstream of the flow.

Next, a fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment is an application of the fourth embodiment, in which the resonance pipe 59 is provided between the second silencing chamber 2B and the resonance chamber 2D, but the exhaust gas flows from the first silencing chamber 2A to the resonance pipe 59. It differs from the fourth embodiment in that it flows in, and the other basic configuration is the same as that of the fourth embodiment. In FIG. 6 showing the overall configuration, an exhaust muffler 50 of the fifth embodiment includes a drum-shaped main body 2, and a communication pipe 38 and a resonance pipe 59 are provided in the main body 2. The resonance tube 59 has the same configuration as the resonance tube 29 of the second embodiment, and has a partition wall 59A at the end on the second sound deadening chamber 2B side.
Is provided on the outer periphery and at the end on the side of the second silencing chamber 2B.
A large number of communication holes 59B facing the silencing chamber 2A are formed.

The operation of the fifth embodiment will be described. In the fifth embodiment, the exhaust gas sent to the exhaust gas introduction pipe 6 is transmitted from the first muffler chamber 2A located at the most upstream side through the communication pipe 38 to the most downstream side by the same operation as the above-described embodiments. Is exhausted to the tail pipe 7 from the third silencing chamber 2C. At this time, the exhaust noise of the exhaust gas is reduced by the flow of the exhaust gas between the silencing chambers 2A, 2B, and 2C and the communication holes 8A1 to 8A4 of the communication pipe 38.

On the other hand, the exhaust gas flowing from the exhaust gas introduction pipe 6 enters the communication pipe 8 through the communication hole 8A1, but at the same time, the resonance pipe 59 and the resonance chamber 2D generate a primary combustion noise of about 100 Hz, for example. Sound in a specific frequency range is muted, thereby reducing noise in a specific frequency range.

In the fifth embodiment, (1) to (1) of the first embodiment will be described.
(7) In addition to the effects of (10) of the fourth embodiment, the following effects can be obtained. (11) Even if the resonance chamber 2D is provided adjacent to the first muffler chamber 2A and on the opposite side of the downstream side of the flow, the resonance pipe 59 and the resonance chamber 2D make the first muffler chamber 2A the most. In a close position,
Sound in a specific frequency range of, for example, about 100 Hz, such as a primary sound of combustion, is eliminated, whereby noise in a specific frequency range can be reduced.

Next, a sixth embodiment of the present invention will be described with reference to FIG. The sixth embodiment is different from the first embodiment in that two communication tubes 8 are provided in the first embodiment and the resonance tube 9 is arranged between the communication tubes 8 in the first embodiment. This is the same as the first embodiment. In FIG. 7 showing the overall configuration, an exhaust silencer 60 according to a sixth embodiment includes a drum-shaped main body 2, and two main bodies 2 disposed at symmetrical positions with respect to the axis of the main body 2. Is supported by the first, second, and third partition plates 3A, 3B, and 3C, and the resonance tube 9 is disposed between the two communication tubes 8 and on the axis of the main body 2. The first and second partition plates 3A and 3B support the first and second partition plates, respectively.

The operation of the sixth embodiment will be described. In the sixth embodiment, the exhaust gas sent to the exhaust gas introduction pipe 6 passes through the two communication pipes 8 from the first muffler chamber 2A located on the most upstream side, and then reaches the third muffler chamber 2C at the lowermost stream. From the tail pipe 7. At this time, each muffling room 2
The exhaust noise of the exhaust gas is suppressed by the restriction and expansion at the time of inflow and discharge between A, 2B and 2C and the respective communication holes 8A1 to 8A4 in the respective communication pipes 8.

On the other hand, the exhaust gas flowing from the exhaust gas introduction pipe 6 flows into the two communication pipes 8 from the first silencing chamber 2A, but at the same time, the primary combustion gas flows through the resonance pipe 9 and the resonance chamber 2D. As a result, a sound in a specific frequency range of, for example, about 100 Hz, such as a sound, is eliminated, so that noise in a specific frequency range is reduced.

In the sixth embodiment, the effects (1) to (7) except for (2) of the first embodiment can be obtained.

Next, a seventh embodiment of the present invention will be described with reference to FIG. The seventh embodiment is different from the first embodiment in that two resonance tubes 9 are provided between the first silencing chamber 2A and the resonance chamber 2D, but the basic configuration is the same as the first embodiment. is there. In FIG. 8 showing the overall configuration, an exhaust silencer 70 of the seventh embodiment includes a drum-shaped main body 2 and a communication pipe 8 provided with first, second, and third partition plates 3A,
3B and 3C, the two resonance tubes 9 are first and second resonance tubes.
Are supported by the partition plates 3A and 3B, respectively. The two resonance tubes 9 are, for example, 1
They are arranged facing each other by 80 °.

The operation of the seventh embodiment will be described. In the seventh embodiment, similarly to the first embodiment, the exhaust gas sent to the exhaust gas introduction pipe 6 passes through the communication pipe 8 from the first muffler chamber 2A located on the most upstream side to the third most downstream third muffler.
Is exhausted to the tail pipe 7 from the silencing chamber 2C. Communication holes 8A1 to 8A4 of each of the silencing chambers 2A, 2B, 2C and the communication pipe 8.
The exhaust noise of the exhaust gas is eliminated by restricting and expanding at the time of inflow and discharge between and.

On the other hand, the exhaust gas flowing into the first silencing chamber 2A flows from the first silencing chamber 2A into the communication pipe 8 as described above, but at the same time, the two resonance pipes 9 and 2D so,
As a result of eliminating a sound in a specific frequency range of, for example, about 100 Hz, such as a primary sound of combustion, noise in a specific frequency range is also reduced.

In the seventh embodiment described above, the first embodiment
In addition to the effects of (1) to (7), the following effects can be obtained. (12) Since two resonance tubes 9 are provided, the energy excited by the resonance tubes 9 increases, and as a result, the resonance tubes 9
And the resonance chamber 2D, for example, 100H
Sound in a specific frequency range of about z is extinguished, whereby noise in a specific frequency range can be reduced.

Next, an eighth embodiment of the present invention will be described with reference to FIG. The eighth embodiment is an application of the seventh embodiment. A sound absorbing material chamber 81 for storing a sound absorbing material is provided at the position of the resonance chamber 2D of the communication pipe 8, and a sound absorbing material chamber for storing the sound absorbing material in the tail pipe 87. The difference from the seventh embodiment lies in that 83 is provided, but the basic configuration is the same as that of the seventh embodiment. In FIG. 9 showing the overall configuration, an exhaust silencer 90 according to an eighth embodiment includes a drum-shaped main body 2.
Is provided with the communication tube 8 and two resonance tubes 9.

As described above, the resonance chamber 2
A sound absorbing material chamber 81 is provided at the position D.
1 stores glass wool 82 as a sound absorbing material. On the other hand, many small holes 8A5 are formed on the outer periphery of the communication pipe 8 corresponding to the sound absorbing material chamber 81. Therefore, the communication pipe 8 and the glass wool 82 in the sound absorbing material chamber 81 are communicated with each other through the many small holes 8A5.

The sound absorbing material chamber 81 is formed of, for example, a thin plate.
The shape is a combination of two semi-cylindrical members having lids at both ends, and the glass wool 82 covering the outer periphery of the communication pipe 8 is pressed down from the outside by each semi-cylindrical member, and the flange portion provided on each semi-cylindrical member is, for example, bolted. By being connected, they are integrally attached to the communication pipe 8.

The sound absorbing material chamber 83 on the tail pipe 87 side
Is provided inside a straight pipe portion 87C that constitutes the tail pipe 87 together with the curved pipe portion 87B. That is, the sound absorbing material chamber 83 includes an upper pressing member 83A fixed to the upper end portion of the straight pipe portion 87B and a lower pressing member 83B fixed to the lower end portion. These upper pressing member 83A and lower pressing member 83B.
A cylindrical member 83C formed with a large number of small holes 87D and having a diameter smaller than that of the straight pipe portion 7B, for example, made of punching metal is integrally provided, and a glass wool 84 is wound around the outer periphery of the cylindrical member 83C. ing.

The operation of the eighth embodiment will be described. In the eighth embodiment, similarly to the seventh embodiment, the exhaust gas sent to the exhaust gas introduction pipe 6 passes through the communication pipe 8 from the first muffler chamber 2A located on the most upstream side and reaches the third downstream end via the communication pipe 8.
Is exhausted to the tail pipe 7 from the silencing chamber 2C. Communication holes 8A1 to 8A4 of each of the silencing chambers 2A, 2B, 2C and the communication pipe 8.
The exhaust noise of the exhaust gas is eliminated by restricting and expanding at the time of inflow and discharge between and. When the exhaust gas flows through the inside of the communication pipe 8, at the position of the resonance chamber 2 </ b> D, the small hole 8 </ b> A <b> 5
1 is sent to the glass wool 82. At this point, the exhaust sound of the exhaust gas is absorbed by the glass wool 82 and is silenced.

When the exhaust gas that has expanded from the communication hole 8A4 of the communication pipe 8 and flowed into the third silencing chamber 2C flows through the straight pipe portion 87B of the tail pipe 87, a part of the small
7D flows into the sound absorbing material chamber 83, and at this time, the exhaust sound of the exhaust gas is absorbed by the glass wool 84 and is silenced. Further, in the resonance tube 9 and the resonance chamber 2D, similarly to the above-described embodiments, for example, 100 Hz
Sounds in a specific frequency range of a certain degree are muted, so that noise in a specific frequency range can be reduced.

In the eighth embodiment described above, the first embodiment
In addition to the effects of (1) to (7) and the effects of (12) of the seventh embodiment, the following effects can be obtained. (13) The exhaust sound of the exhaust gas is silenced from the first silencing chamber 2A to the third silencing chamber 2C via the communicating pipe 8 and is provided at the position of the resonance chamber 2D in the communicating pipe 8. The sound is also absorbed by the glass wool 82 in the sound absorbing material chamber 81 and the glass wool 84 in the sound absorbing material chamber 83 on the tail pipe 87 side, so that a further noise reduction effect can be obtained.

The present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved. For example,
In each of the above embodiments, the communication pipe 8 and the like are formed in the same straight shape with the same cross-sectional area along the axial direction. However, the present invention is not limited to this. In the present invention, as shown in FIG. Venturi section 9 having a smooth constricted section and an enlarged section
8C may be formed. That is, in this variant,
Instead of the second tubular portion 8B of the seventh embodiment, a second tubular portion 98B partially formed with a venturi portion 98C is used. In this way, the flow of the exhaust gas inside the communication pipe 98 is adjusted, and the venturi section 98 is formed.
As a result of being squeezed at C, a silencing effect is also obtained. Note that a diffuser may be used instead of the venturi section 98C.

In the second and fifth embodiments,
Partition walls 29A, 5 are provided at the ends of the resonance tubes 29, 59 on the side of the resonance chamber 2D.
Although 9A is provided and supported by the second support 3G, the present invention is not limited to this. The second support 3G is not provided on the second partition plate 3B, and the ends of the resonance tubes 29 and 59 on the side of the resonance chamber 2D are connected. The second partition plate 3B may be directly abutted and fixed to the disk portion 3D of the second partition plate 3B. By doing so, the labor for forming the second support portion 3G can be saved, and the labor for attaching the partition walls 29A and 59A can be saved.

Furthermore, in each of the above-described embodiments, one resonance chamber and three muffling chambers are provided. However, the present invention is not limited to this. Two or more resonance chambers and three or more muffling chambers are provided. It may be provided. However, if too many resonance chambers and muffling chambers are provided, the whole muffling device becomes large and the weight becomes heavy.
Attention is required.

Further, although the exhaust mufflers 10, 20 and the like are applied to a diesel engine, they may be applied to an internal combustion engine such as a gasoline engine, and this internal combustion engine is not limited to those used for construction machines. And those used for passenger cars and the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of an exhaust silencer according to a first embodiment of the present invention.

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

FIG. 3 is a cross-sectional view illustrating an overall configuration of an exhaust silencer according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating an overall configuration of an exhaust silencer according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating an overall configuration of an exhaust silencer according to a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating an overall configuration of an exhaust silencer according to a fifth embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating an overall configuration of an exhaust silencer according to a sixth embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating an overall configuration of an exhaust silencer according to a seventh embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating an overall configuration of an exhaust silencer according to an eighth embodiment of the present invention.

FIG. 10 is a cross-sectional view showing an overall configuration of an exhaust silencer according to a modification of the present invention.

[Explanation of symbols]

2A, 2B, 2C First, second, third muffling chamber 2 Main body 3A, 3B, 3C First, second, third partition 6A Exhaust gas inlet 7A, 87A Exhaust gas outlet 8, 28, 38,98 Communication pipe 8A1-8A4 Communication hole 9,29,39,49,59 Resonance pipe 10,20,30,40,50,60,70,80 Exhaust silencer

Claims (7)

[Claims] 1. An exhaust silencer connected to an exhaust pipe of an internal combustion engine, wherein at least one resonance chamber through which exhaust gas of the internal combustion engine does not substantially flow, and at least three chambers through which the exhaust gas flows An exhaust gas inlet for directly flowing the exhaust gas into the uppermost one of these mufflers is provided,
An exhaust gas outlet for allowing the exhaust gas to flow out is provided in the most downstream muffler chamber, and a communication pipe is provided for allowing the exhaust gas to flow between the plurality of muffler chambers. A plurality of communication holes are provided at predetermined positions on the outer periphery of the communication pipe, the communication holes corresponding to the muffler chambers to be communicated with each other, and the resonance chamber resonates with any one of the muffler chambers. An exhaust silencer characterized by being communicated with a pipe. 2. The exhaust silencer according to claim 1, wherein the communication pipe is constituted by a single pipe. 3. The exhaust muffler according to claim 1, further comprising: a main body provided with partition walls at both ends and the muffling chamber and the resonance chamber provided therein, wherein the main body has a substantially axial center. An exhaust silencer, wherein the communication pipe is arranged so that the axes thereof are aligned with each other, and the resonance pipe is arranged around the communication pipe. 4. The exhaust muffler according to claim 1, wherein a cross-sectional area of the communication pipe is 5 to 30% of a cross-sectional area of the muffling chamber.
An exhaust silencer characterized by the following. 5. The exhaust muffler according to claim 1, wherein a smooth throttle portion and an enlarged portion are provided in a resonance chamber of the communication pipe. Silencer. 6. The exhaust noise reduction device according to claim 1, wherein a sound absorbing material chamber for receiving a sound absorbing material is provided at a position of the resonance chamber of the communication pipe. An exhaust silencer characterized in that the communication pipe is connected to the communication pipe via a number of small holes formed in the communication pipe. 7. The exhaust noise reduction device according to claim 1, wherein a bypass hole is provided in a partition wall that does not include the resonance chamber among partition walls that partition the respective noise reduction chambers. Exhaust silencer characterized.