JP2005240720A - Muffler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a muffler capable of reducing exhaust noise while suppressing increase in air-flow resistance. <P>SOLUTION: In the muffler with a multiple chamber structure in which a large number of expansion chambers 11, 12, 13 are provided and each of communication tubes 15, 16, 17 is sequentially communicated with each of the expansion chambers 11, 12, 13, at least one of the communication tubes 15, 16, 17 provided after the downstream side of the second expansion chamber 12 in the order of exhaust gas flow is fully or partially equipped with an assembly 18 of a large number of thin tubes. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a silencer having a multi-chamber structure.

  A multi-chamber silencer is generally used in which the interior of the cylindrical case is partitioned by a partition wall and each room is connected by a communication pipe. Has been adopted.

  And using the dispersibility of the porous metal in anticipation of further silencing effect, the outer periphery of the porous metal plate is held by the partition plate, and the partition plate is attached to the front part of the muffler cylinder so as to partition in the front-rear direction. There is an example (for example, refer to Patent Document 1).

Japanese Utility Model Publication No. Sho 62-110515 (claims for registration of utility model, FIGS. 1 and 2)

  By partitioning the front part of the muffler cylinder with a partition plate holding a porous metal plate, the entire amount of exhaust gas permeates through the porous metal plate at an early stage to disperse the pressure, thereby increasing the silencing effect.

  However, each hole of the porous metal plate is not formed linearly, and the porous metal plate tries to permeate the entire amount of exhaust gas at the front part of the muffler cylinder, so that the ventilation resistance is extremely large. The internal pressure of the exhaust system is increased, and the engine output is reduced.

  Some of the porous metal plates are provided with a honeycomb cylindrical catalyst carrier, but for the purpose of purifying exhaust gas, it is also arranged on the upstream side of the exhaust gas in order to quickly raise the catalyst activation temperature. Resistance is difficult to suppress.

  This invention is made | formed in view of such a point, The process which makes it the objective is to provide the silencer which can reduce exhaust noise, suppressing the increase in ventilation resistance.

Means and effects for solving the problems

  In order to achieve the above object, according to the first aspect of the present invention, in a muffler having a multi-chamber structure in which a plurality of expansion chambers are provided and each communication pipe communicates with each other in order, the second exhaust gas flows in the order in which the exhaust gas flows. At least one of the communication pipes provided after the downstream of the expansion chamber was a silencer provided with an aggregate of a large number of thin tubes in whole or in part.

  The communication pipe having an aggregate of a large number of thin tubes rectifies the exhaust gas flow into a laminar flow to prevent the collision noise of the air flow, and can reduce the natural frequency, so that the silencing effect is large even with a small capacity. An increase in ventilation resistance can be suppressed by forming a laminar flow provided downstream of the expansion chamber.

  According to a second aspect of the present invention, in the silencer according to the first aspect, a plurality of the communication pipes are supported by a partition wall that partitions the expansion chamber.

  By supporting multiple communication pipes on a common partition, the number of parts can be reduced and the structure can be simplified.

  According to a third aspect of the present invention, in a multi-chamber silencer having a plurality of expansion chambers and each communication pipe communicating with each other in order, exhaust gas is discharged from the last expansion chamber in the order in which the exhaust gas flows. The tailpipe is a silencer having an assembly of a large number of thin tubes.

  A tailpipe with a large number of thin tube assemblies rectifies the flow of exhaust gas into a laminar flow to prevent airflow impingement noise and can reduce the natural frequency. By forming, an increase in ventilation resistance can be suppressed.

  According to a fourth aspect of the present invention, in the silencer according to the first or third aspect, the assembly is configured as a corrugated plate and a flat tube.

  It can be manufactured from a thin steel plate, and the hindrance to the flow of exhaust gas can be minimized.

  According to a fifth aspect of the present invention, in the silencer according to the first or third aspect, the aggregate is a ceramic honeycomb structure.

  By using a ceramic honeycomb structure, an aggregate of a large number of thin tubes excellent in heat resistance can be formed.

  The invention according to claim 6 is a silencer that is connected to an exhaust pipe that communicates with an internal combustion engine, includes a plurality of expansion chambers, the communication tubes communicate with each other, and a tail pipe projects from the expansion chamber to the outside. It is a silencer provided with an aggregate of many thin tubes in two or more of the exhaust pipe, the communication pipe, and the tail pipe.

By providing a large number of narrow tube assemblies in two or more of the exhaust pipe, communication pipe, and tail pipe, the flow of exhaust gas is rectified into a laminar flow to prevent airflow collision noise and reduce the natural frequency. Therefore, it can be expected that the noise reduction effect will increase even with a small capacity.
Further, since the aggregate rectifies the flow of exhaust gas into a laminar flow, an increase in ventilation resistance can be suppressed.

An embodiment according to the present invention will be described below with reference to FIGS.
The silencer 1 according to the present embodiment is connected to a downstream end of an exhaust pipe 0 extending from an exhaust port of an internal combustion engine suspended on a body frame by a silencer for a motorcycle.

  FIG. 1 is a longitudinal sectional view of the silencer 1. A cylindrical case 2 is connected to a front end wall 3 that closes the front end opening by fitting an exhaust pipe 0 to the rear end wall 4 that closes the rear end opening. The tail pipe portion 17a of the third communication pipe 17 is inserted.

The inside of the cylindrical case 2 lined with glass wool 2a is partitioned into three rooms in the front-rear direction by partition walls 5 and 6.
The front chamber into which the exhaust pipe 0 is inserted is the first expansion chamber 11, the rear chamber is the second expansion chamber 12, and the chamber sandwiched between the first expansion chamber 11 and the second expansion chamber 12 is This is the third expansion chamber 13.

  The first communication pipe 15 communicates with the first expansion chamber 11 and the second expansion chamber 12 through the partition walls 5 and 6, and the second expansion chamber 12 and the third expansion chamber 13 pass through the partition wall 6 with the second expansion chamber 12. Two communication pipes 16 communicate with each other, and the third communication pipe 17 penetrates the partition wall 6 and the rear end wall 4 to communicate the third expansion chamber 13 with the outside.

A straight portion in the middle of the third communication pipe 17 is composed of a rectifying pipe 18 in which a large number of thin tubes are assembled as shown in FIG.
For example, a straightening tube 18 that is an aggregate of a large number of thin tubes that form elongated holes is formed by superposing a flat plate made of a stainless steel plate and a corrugated plate and winding them in a spiral shape.
The steel plate is very thin and has a structure that minimizes the hindrance to exhaust gas flow.

A third communication pipe 17 is welded to both ends of such a rectifying pipe 18.
The rectifying pipe 18 may be inserted into the third communication pipe 17 and fixed by brazing or welding.

  The silencer 1 has the above-described structure, and the exhaust gas guided to the exhaust pipe 0 is first introduced into the first expansion chamber 11 and then the second expansion chamber via the first communication pipe 15. 12, then introduced into the third expansion chamber 13 through the second communication pipe 16, and discharged to the outside from the third expansion chamber 13 through the third communication pipe 17.

  The exhaust gas expands every time it enters the first, second, and third expansion chambers 11, 12, and 13, so that the pressure wave is dispersed stepwise and can be silenced.

  Then, the flow of exhaust gas is rectified from turbulent flow to laminar flow by the rectifying tube 18 which is a collection of thin tubes provided in the third communication pipe 17 to prevent the collision noise of the air flow, thereby further enhancing the silencing effect.

Since the narrow tube of the rectifying tube 18 has a small cross-sectional area, a noise reduction effect can be expected by reducing the natural frequency of the rectifying tube itself.
Therefore, unlike the conventional expansion silencer, it is not necessary to increase the capacity to enhance the silencing effect, and the silencer itself is miniaturized and the degree of freedom in design layout such as the mounting position on the vehicle body is high.

  The rectifying pipe 18 of the third communication pipe 17 is capable of suppressing an increase in ventilation resistance by making the flow of exhaust gas into a laminar flow that flows linearly and flowing smoothly, and is provided with a rectifying pipe 18. The three communication pipes 17 are located downstream of the third expansion chamber 13 and are not provided in the first expansion chamber 11 in a state where the pressure wave is large, so that the ventilation resistance is further reduced and the internal pressure of the exhaust system is increased. Reduction of the engine output can be prevented.

A silencer 31 according to another embodiment will be described with reference to FIGS.
The present silencer 31 is the same as the silencer 31 except that the silencer 1 and the third communication pipe 17 are different third communication pipes 32.
Therefore, the same member uses the same symbol.

The rectifying pipe 18 is provided in the straight line part in the middle of the third communication pipe 17, but in the third communication pipe 32, the rectifying pipe 33 is provided in the tail pipe part.
As shown in FIG. 4, the rectifying tube 33 is formed of a ceramic honeycomb structure in which a large number of thin tubes having elongated holes are gathered by a lattice wall.
Note that a rectifying tube having a honeycomb structure may be formed by metal extrusion.

Even if the rectifying pipe 33 is provided in the tail pipe portion of the third communication pipe 32, the same effect as in the above embodiment can be obtained.
That is, exhaust noise can be reduced while suppressing an increase in ventilation resistance with a small capacity.

FIG. 5 shows a silencer 41 according to another embodiment.
The mufflers 1 and 31 according to the above embodiment, the second communication pipe 42 and the third communication pipe 43 are different, the others are the same, and the same members use the same reference numerals.

  The second communication pipe 42 of the silencer 41 is composed of a rectification pipe 42a in which a large number of thin tubes are all gathered, and the third communication pipe 43 is composed of a rectification pipe 44 in which a large number of thin tubes are gathered in the upstream straight portion. .

  The two communication pipes 42 and 43 are respectively provided with rectifying pipes 42a and 44, both of which are arranged downstream of the second expansion chamber 12 and are connected to the first expansion chamber 11 having a large pressure wave. Is not provided, the ventilation resistance is not increased. Therefore, substantially the same effect as the silencer 1 and the silencer 31 of the above embodiment can be obtained.

Next, an embodiment of the silencer 51 having two expansion chambers will be described with reference to FIG.
In the silencer 51, a cylindrical case 52 is partitioned by a partition wall 53 into a first expansion chamber 54 on the rear side and a second expansion chamber 55 on the front side, and an exhaust pipe 50 communicating with the internal combustion engine is provided on the second expansion chamber on the front side. The first expansion chamber 54 is inserted into the front end wall of 55, protrudes through the second expansion chamber 55 and the partition wall 53 and protrudes into the first expansion chamber 54. A first communication pipe 56 communicates, and a second communication pipe 57 communicates between the second expansion chamber 55 and the outside through the partition wall 53 and the rear end wall.

  In the silencer 51, a number of narrow pipes are respectively connected to the downstream end of the exhaust pipe 50, the upstream and downstream ends of the first communication pipe 56, and the tail pipe portions of the upstream and downstream ends of the second communication pipe 57. Rectifier tubes 58a, 58b, 58c, 58d, and 58e, which are aggregates, are provided.

  The exhaust gas expands every time it enters the first and second expansion chambers 54 and 55, and the pressure waves are dispersed in stages to silence the exhaust gas, but the exhaust pipe 50, the first communication pipe 56, and the second communication pipe 57 respectively. The flow of exhaust gas is rectified from turbulent flow to laminar flow by the rectifying pipes 58a, 58b, 58c, 58d, and 58e provided in the air flow to prevent the collision noise of the air flow, and the silencing effect is increased more and more.

  Each of the rectifying pipes 58a, 58b, 58c, 58d, and 58e suppresses an increase in ventilation resistance as much as possible by making the exhaust gas flow into a laminar flow that flows linearly and smoothly.

Next, an embodiment of a silencer 61 having two other expansion chambers will be described with reference to FIG.
In the silencer 61, a cylindrical case 62 is partitioned by a partition wall 63 into a front first expansion chamber 64 and a rear second expansion chamber 65, and an exhaust pipe 60 communicating with the internal combustion engine is a front first expansion chamber. 64 is inserted into the front end wall of 64, penetrates the partition wall 63, the first communication chamber 66 communicates with the first expansion chamber 64 and the second expansion chamber 65, passes through the rear end wall and the second expansion chamber 65 and the outside. And a second communication pipe 67 communicates with each other.

  In the silencer 61, the downstream end of the exhaust pipe 60, the upstream end and the downstream end of the first communication pipe 66, and the tail pipe portion of the upstream end and the downstream end through the bent part of the second communication pipe 67, respectively Rectifier tubes 68a, 68b, 68c, 68d, and 68e, which are aggregates of a large number of thin tubes, are provided.

The silencer 61 of the present embodiment can achieve the same effects as the silencer 51 of the embodiment.
That is, in addition to the silencing by the first and second expansion chambers 64 and 65, the silencing by the rectifying pipes 68a, 68b, 68c, 68d and 68e can provide a high silencing effect, and the rectifying pipes 68a, 68b and 68c. , 68d, 68e suppresses increase in ventilation resistance as much as possible.

  In addition, the installation of the rectifying pipe as an assembly is not limited to the above-described embodiment, and can be appropriately arranged in any one of the exhaust pipe, the communication pipe, and the tail pipe, or two or more of them. is there.

It is a longitudinal cross-sectional view of the silencer which concerns on one embodiment of this invention. It is a perspective view which shows the structure of the rectifier pipe used for the silencer. It is a longitudinal cross-sectional view of the silencer which concerns on another embodiment. It is a perspective view which shows the structure of the rectifier pipe used for the silencer. It is a longitudinal cross-sectional view of a silencer according to another embodiment. It is a longitudinal cross-sectional view of the silencer which concerns on another embodiment. It is a longitudinal cross-sectional view of the silencer which concerns on another embodiment.

Explanation of symbols

0 ... exhaust pipe,
DESCRIPTION OF SYMBOLS 1 ... Silencer, 2 ... Cylindrical case, 3 ... Front end wall, 4 ... Rear end wall, 5, 6 ... Partition, 11 ... 1st expansion chamber, 12 ... 2nd expansion chamber, 13 ... 3rd expansion chamber, 15 ... 1st communication pipe, 16 ... 2nd communication pipe, 17 ... 3rd communication pipe, 18 ... Rectification pipe,
31 ... Silencer, 32 ... Third communication pipe, 33 ... Rectifier pipe,
41 ... Silencer, 42 ... Second communication pipe, 42a ... Rectification pipe, 43 ... Third communication pipe, 44 ... Rectification pipe,
50 ... exhaust pipe, 51 ... silencer, 52 ... cylindrical case, 53 ... partition wall, 54 ... first expansion chamber, 55 ... expansion chamber, 56 ... first communication tube, 57 ... second communication tube, 58a, 58b, 58c, 58d, 58e ... Rectifier tube,
60 ... exhaust pipe, 61 ... silencer, 62 ... cylindrical case, 63 ... partition wall, 64 ... first expansion chamber, 65 ... expansion chamber, 66 ... first communication pipe, 67 ... second communication pipe, 68a, 68b, 68c, 68d, 68e ... Rectifier tube.

Claims (6)

In a muffler having a multi-chamber structure in which a large number of expansion chambers are provided and each communication pipe communicates with each other in sequence.
A muffler characterized in that at least one of the communication pipes provided downstream and downstream of the second expansion chamber in the order in which the exhaust gas flows includes a collection of a plurality of thin tubes in whole or in part. The silencer according to claim 1, wherein a plurality of the communication pipes are supported by a partition wall that partitions the expansion chamber. In a muffler having a multi-chamber structure in which a large number of expansion chambers are provided and each communication pipe communicates with each other in sequence.
A silencer characterized in that a tail pipe for discharging exhaust gas to the outside from the last expansion chamber in the order in which the exhaust gas flows includes a collection of a plurality of thin tubes. The silencer according to claim 1 or 3, wherein the aggregate is configured as a corrugated plate and a flat wound tube. The silencer according to claim 1 or 3, wherein the aggregate is a ceramic honeycomb structure. In a silencer that is connected to an exhaust pipe that communicates with an internal combustion engine, includes a plurality of expansion chambers, the communication pipes communicate with each other, and a tail pipe projects from the expansion chamber to the outside.
2. A silencer comprising an assembly of a plurality of thin tubes in two or more of the exhaust pipe, the communication pipe, and the tail pipe.

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