JP2000303821A - Exhaust muffler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust muffler which is increased in noise-eliminating capacity by limited capacity rectangular parallelopiped and improved in noise elimination effect by small number of inner pipes. SOLUTION: The space inside a muffler main body 1 prepared by fixing end plates 3a, 3b to both ends of a rectangular cylindrical casing 2 is divided into a plurality of expansion chambers 7a to 7c by means of baffle plates 5, 6. The adjacent expansion chambers 7a, 7b communicate with each other by means of a first inner pipe 10. In addition, an inlet pipe and an outlet pipe 9 are provided. In such an insertion pipe expansion type exhaust muffler, swollen out portions 4a, 4b directed outward are formed on plate surfaces of end plates 11a, 11b. A number of through-holes 12a to 12d are formed on back plates 11a, 11b by means of punching or the like, and the back plates are attached to the inner sides of the end plates 11a, 11b. The swollen out portions 4a, 4b serve as clearance passages 13a, 13b between the end plates 3a, 3b and the back plates 11a, 11b. A second inner pipe 14 communicates with the clearance passages 13a, 13b.

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 a rectangular cylindrical casing.

[0002]

2. Description of the Related Art An exhaust muffler of an insertion pipe type that silences exhaust sound of an engine includes an exhaust muffler of a cylindrical casing having a plurality of expansion chambers partitioned by a baffle plate and an exhaust muffler of a square cylindrical casing. is there.

[0003]

The exhaust muffler of the rectangular tubular casing has a flattened expansion chamber and a larger capacity than the exhaust muffler of the cylindrical casing. Direction length is reduced,
There is an advantage that the installation condition to the vehicle is advantageous due to the outer shape of the rectangular tube. However, the exhaust muffler of the cubic rectangular cylindrical casing has a small noise-muffling power for its volume. As a countermeasure, based on the noise reduction theory that the attenuation increases at a frequency at which the effective length of the insertion tube is an odd multiple of 1/4 wavelength, a number of inner pipes communicating between the expansion chambers are provided and the noise reduction capacity is sufficiently used. Like that. For this reason, the number of inner pipes used has increased, and accordingly, the number of steps for attaching the inner pipes to the baffle plate, the weight, the cost, and the like have increased.

[0004] It is an object of the present invention to provide an exhaust muffler in which the capacity for noise reduction is increased with a limited volume of a rectangular parallelepiped (including a cube or the same hereinafter) and the noise reduction effect is improved by a small number of inner pipes.

[0005]

In order to achieve the above object, the present invention provides a muffler body in which end plates are fixed to both ends of a rectangular cylindrical casing, and a plurality of expansion chambers are formed by a plurality of baffle plates. In an insertion-pipe expansion type exhaust muffler which is partitioned and has an inner pipe communicating between adjacent expansion chambers, and an inlet pipe and an outlet pipe communicating with the expansion chamber, the exhaust pipe faces outward on the plate surface of the end plate. A swelling portion is formed, and a back plate having a through hole is fixedly provided on an inner surface of the end plate, and the swelling portion is formed as a gap passage between the end plate and the back plate. An inner pipe communicating with the passage is provided.

Further, a plurality of expansion chambers are defined by a plurality of baffle plates in a muffler main body having end plates fixed to both ends of a rectangular cylindrical casing, and an inner pipe communicating between adjacent expansion chambers; In an insertion pipe type expansion type exhaust muffler provided with an inlet pipe and an outlet pipe communicating with the expansion chamber, an outward bulging portion is formed on a plate surface of the end plate, and an inner side surface of the end plate is formed. An inward bulging portion facing the bulging portion of the end plate is formed, and a back plate having a through hole formed therein is fixed to the bulging portion, and the bulging portion is provided between the end plate and the back plate. The outlet portion is formed as a clearance passage, and an inner pipe communicating with the clearance passage is provided.

Further, a plurality of expansion chambers are defined by a plurality of baffle plates in a muffler main body in which end plates are fixed to both ends of a rectangular cylindrical casing, and an inner pipe communicating between adjacent expansion chambers; In an insertion pipe type expansion type exhaust muffler provided with an inlet pipe and an outlet pipe communicating with the expansion chamber, the end plate is made flat, and an inward bulging portion is formed on an inner surface of the end plate. A back plate having a through hole formed in the bulging portion is fixed, the bulging portion is formed as a gap passage between the end plate and the back plate, and an inner pipe communicating with the gap passage is provided. It is a feature.

[0008] The inner pipe communicated with the clearance passage,
It is formed so as to communicate with a gap passage formed between the end plates and the back plate.

[0009] The inner pipe communicating with the clearance passage,
It is formed so as to communicate with a gap passage formed between one end plate and the back plate.

[0010] A catalyst for communicating between adjacent expansion chambers is arranged in the expansion chamber.

[0011] The through-hole formed in the back plate is characterized by having a number of small holes formed by punching.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show a first embodiment of the present invention. FIG. 1 is an end view seen from the left side of FIG.
2 is a sectional view taken along line AA of FIG. 1, FIG. 3 is a sectional view taken along line BB of FIG. 1, FIG. 4 is a sectional view taken along line CC of FIG. 1, and FIG. FIG. 6 is a cross-sectional view taken along line EE of FIG. 2. 7 to 10 show a second embodiment of the present invention. FIG. 7 is an end view seen from the left side of FIG. 8, FIG. 8 is a sectional view taken along line FF of FIG. 7, and FIG. FIG. 10 is a sectional view taken along line HH of FIG. 8, FIG. 10 is a sectional view taken along line GG of FIG.
1 is a sectional view of a main part showing another embodiment, and FIG.
1 is a view as viewed from the direction of the arrow J.

[Configuration of First Embodiment] As shown in FIGS. 1 to 6, the muffler main body 1 is a rectangular tubular casing 1, and end plates 3a and 3b are fixed to both ends of the casing 1. . On the plate surfaces of the end plates 3a, 3b, outwardly protruding portions 4a, 4b (beads) are formed, and the inside of the muffler body 1 is formed by two baffle plates 5, 6 in a first expansion chamber 7a. , The second extension room 7b, and the third extension room 7c
The first expansion room 7a and the second expansion room 7
b are communicated by two first inner pipes 10.

From the one end plate 3a side, the first expansion chamber 7a
And an inlet pipe 8 communicating with the second expansion chamber 7b and an outlet pipe 9 penetrating the first expansion chamber 7a and the second expansion chamber 7b and communicating with the third expansion chamber 7c.

The inner surfaces of the end plates 3a and 3b have through holes 12 formed therein.
Back plate 11a, 1 that has opened a, 12b, 12c, 12d
1b, the end plates 3a, 3b and the back plates 11a, 1
1b and the bulging portions 4a, 4b
13b, the gap passage 13a of the bulging portion 4a of one end plate 3a communicates with the first expansion chamber 7a through the through holes 12a, 12b, and the bulging portion 4b of the other end plate 3b.
The gap passage 13b communicates with the third expansion chamber 7c through the through holes 12c and 12d. The through hole 12
Reference numerals a, 12b, 12c, and 12d denote a number of small holes formed by punching.

The end plates 3a, 3b and the back plates 11a, 11b
Between the gap passages 13a, 13b of the bulging portions 4a, 4b formed between the first and second expansion chambers 7a, 7b.
b, a second inner pipe 14 is disposed through the third expansion chamber 7c, and one end of the second inner pipe 14 is connected to the end plate 3a.
The other end of the second inner pipe 14 is opened and communicated with the gap passage 13b on the end plate 3b side.

[Operation of the First Embodiment] Exhaust gas is introduced from the inlet pipe 8 into the first expansion chamber 7a and the second expansion chamber 7b, and the exhaust gas entering the second expansion chamber 7b is passed through the first inner pipe 10. It is introduced into the first expansion chamber 7a. The exhaust gas introduced from the second expansion chamber 7b and the exhaust gas introduced from the inlet pipe 8 into the first expansion chamber 7a expand through the through holes 12a and 12b formed in the back plate 11a on one end plate 3a side. The gap enters the gap passage 13a of the projecting portion 4a, passes through the gap passage 13a and is introduced into one end of the second inner pipe 14, and passes through the second inner pipe 14 to form a gap between the bulging portion 4b on the other end plate 4b side. The gas enters the passage 13b, passes through the gap passage 13b, is introduced into the third expansion chamber 7c through the through holes 12c and 12d formed in the back plate 11b on the side of the end plate 3b, and is introduced into the third expansion chamber 7c. The exhausted gas is discharged via the outlet pipe 9.

As described above, the exhaust gas introduced from the inlet pipe 8 reduces the back pressure in the first expansion chamber 7a and the second expansion chamber 7b, and further, the gap passage of the bulging portion 4a on one end plate 3a side. 13a, the second inner pipe 14 longer than the first inner pipe 10, the gap passage 13b of the bulging portion 4b on the other end plate 3b side, and the third expansion chamber 7c reduce the back pressure, thereby reducing the number of inner pipes. The noise reduction performance is improved by the pipe configuration.

The first expansion chamber 7a, the second expansion chamber 7
b, end plates 3a, 3b in addition to the silencing capacity of the third expansion chamber 7c.
Of the second protruding portion 4a, 4b, and the long second communicating with the gap passages 13a, 13b between the gap passages 13a, 13b.
The noise reduction capacity is increased by the inner pipe 14, and in addition, the through holes 12a, 12b,
Since the holes 12c and 12d are perforated holes, the exhaust gas flowing in and out of the holes 12c and 12d can have uneven delays in the pressure wave and the flow, so that the noise reduction performance can be improved even with a few inner pipes.

The general end plates 3a and 3b are liable to cause a drumming phenomenon due to the influence of the pressure wave.
Attaching the back plates 11a and 11b in addition to the beads a and 4b increases rigidity and reduces drumming.

[Structure of the Second Embodiment] The second embodiment of the present invention is basically the same as the first embodiment. That is, the muffler main body 1 is a rectangular cylindrical casing 1, and end plates 3 a and 3 b are fixed to both ends of the casing 1. On the plate surface of the other end plate 3b, a bulging portion 4b facing outward is formed, and the inside of the muffler main body 1 is made up of a first expansion chamber 7a, a second expansion chamber 7b, and a catalyst 15a, 15b described later. Three expansion chambers of the third expansion chamber 7c are partitioned.

From the one end plate 3a side, the first expansion chamber 7a
And an inlet pipe 8 communicating with the second expansion chamber 7b, and an outlet passing through the first expansion chamber 7a, the second expansion chamber 7b, and the second expansion chamber 7c and communicating with the second expansion chamber 7b and the third expansion chamber 7c. A pipe 9 is provided. The baffle plate 5 has through holes 16a, 16a communicating with the first expansion chamber 7a and the second expansion chamber 7b.
b (a large number of small holes formed by punching).

A through hole 12 is formed in the inner surface of the other end plate 3b.
c, 12d is fixedly provided, and the bulging portion 4b is formed between the end plate 3b and the back plate 11b.
The gap passage 13b communicates with the third expansion chamber 7c through the through holes 12c and 12d. One end of each of the second inner pipes 14a and 14b is connected to the gap passage 13b, and the other end of each of the second inner pipes 14a and 14b is connected to the second expansion chamber 7b.

Further, catalysts 15a, 15 communicating with the first expansion chamber 7a and the third expansion chamber 7c are provided in the second expansion chamber 7b.
b.

[Operation of the Second Embodiment] Exhaust gas is introduced from the inlet pipe 8 into the first expansion chamber 7a and the second expansion chamber 7b, and the exhaust gas introduced into the first expansion chamber 7a is opened in the baffle plate 5. Through the through holes 16a, 16b to the second expansion chamber 7b.
And enters the second expansion chamber 7b to join the catalysts 15a and 15a.
b and is introduced into the third expansion chamber 7c. Part of the exhaust gas introduced into the first expansion chamber 7c enters the gap passage 13b of the bulging portion 4b through the through holes 12c and 12d formed in the back plate 11b on the other end plate 3b side, and the gap passage 13b Through to one end of the second inner pipes 14a, 14b,
The second inner pipes 14a and 14b pass through the second expansion chamber 7b to enter the second expansion chamber 7b and the third expansion chamber 7c.
Is discharged through the outlet pipe 9.

As described above, the exhaust gas introduced from the inlet pipe 8 reduces the back pressure in the first expansion chamber 7a, the second expansion chamber 7b, and the third expansion chamber 7c, and further expands on the other end plate 3b side. The gap passage 13b of the outlet 4b, the second inner pipe 14a,
14b reduces the back pressure and improves the silencing performance with a few inner pipe configurations.

The first expansion chamber 7a and the second expansion chamber 7
b, in addition to the silencing capacity of the third expansion chamber 7c, the silencing capacity is increased by the gap passage 13b of the bulging portion 4b of the end plate 3b and the second inner pipes 14a, 14b communicating with the gap passage 13b. The through hole 1 of the back plate 11b
Since the holes 2c and 12d are perforated holes, the exhaust gas flowing into and out of the holes 2c and 12d can have a non-uniform delay in the pressure wave and the flow, so that the silencing performance can be improved even with a few inner pipes.

Further, a catalyst 15a for purifying exhaust gas,
Since 15b is installed in the second expansion chamber 7b, there is no need to separately install a catalyst device in the exhaust path outside the muffler body 1, and the exhaust gas is purified by the catalyst in the form of the compact muffler body 1. can do.

[Other Embodiments] In the above embodiment, the bulging portions 4a, 4b forming the gap passages 13a, 13b are provided.
b has been described on both or one of the end plates 3a and 3b. However, as representatively shown on the end plate 3b side in FIG. Outward bulging portions 4a and 4b are formed, and end plates 3a and 3b are formed.
A rear plate 11a in which bulging portions 40 facing inward facing the bulging portions 4a, 4b of the end plates 3a, 3b are formed on the inner surface of the end plate 3b, and through holes 12a, 12c are formed in the bulging portions 40. , 11
b may be fixed to form gap passages 13a, 13b between the end plates 3a, 3b and the back plates 11a, 11b.

As representatively shown on the side of the end plate 3b in FIG. 11 (b), the end plates 3a and 3b
A back plate 1 in which bulging portions 40 facing inward are formed on the inner side surfaces of the a and 3b, and through holes 12a and 12c are formed in the bulging portions 40.
The end plates 3a, 3b and the back plate 11a,
The gap passages 13a and 13b may be formed between the gap passages 13a and 13b.

In the above embodiment, three expansion chambers 7 are provided.
Although an example in which a, 7b, and 7c are formed is shown, the present invention can be applied to a case in which two or more baffle plates form three or more expansion chambers.

[0032]

As described above, according to the present invention, with a limited rectangular parallelepiped volume, the inner passage formed between the end plate and the back plate and the inner pipe communicating with the inner passage have a small number of inner pipes. The noise reduction performance is improved by increasing the volume for noise reduction by the pipe structure, and the uneven delay of the pressure wave and the flow due to the passage of the exhaust gas into and out of the gap passage, and the drumming phenomenon is reduced by improving the rigidity of the end plate. can do. Further, the number of parts can be reduced by reducing the number of inner pipes, and the weight and cost can be reduced by reducing the number of assembly steps. Further, by arranging the catalyst in the muffler main body, the exhaust gas can be purified by the catalyst in a compact form.

[Brief description of the drawings]

1 is a left end view of FIG. 2;

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

FIG. 5 is a sectional view taken along line DD of FIG. 2;

FIG. 6 is a sectional view taken along line EE of FIG. 2;

FIG. 7 is a left end view of FIG. 8 showing another embodiment.

8 is a sectional view taken along the line FF of FIG. 7;

FIG. 9 is a cross-sectional view taken along line HH of FIG. 8;

FIG. 10 is a sectional view taken along line FF of FIG. 7;

FIG. 11 is a sectional view of a main part showing another embodiment.

FIG. 12 is a view taken in the direction of arrow J in FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Muffler main body 2 Casing 3a, 3b End plate 4a, 4b Swelling part 5 Baffle plate 6 Baffle plate 7a First expansion room 7b Second expansion room 7c Third expansion room 8 Inlet pipe 9 Outlet pipe 10 First inner pipe 11a 11b Back plate 12a-12d Through holes 13a, 13b Gap passages 14, 14a, 14b Second inner pipe 15a, 15b Catalyst 16a, 16b Through hole

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F01N 3/28 301 F01N 3/28 301G

Claims (7)

[Claims] An inner pipe, in which a plurality of expansion chambers are defined by a plurality of baffle plates inside a muffler body in which end plates are fixed to both ends of a rectangular cylindrical casing, and an inner pipe communicating between adjacent expansion chambers, In an insertion pipe type exhaust muffler provided with an inlet pipe and an outlet pipe communicating with the expansion chamber, an outward bulging portion is formed on a plate surface of the end plate, and a through-hole is formed on an inner surface of the end plate. An exhaust muffler, wherein a back plate having a hole is fixed, the bulging portion is formed as a gap passage between the end plate and the back plate, and an inner pipe communicating with the gap passage is provided. . 2. A muffler body in which end plates are fixed to both ends of a rectangular cylindrical casing, a plurality of expansion chambers are defined by a plurality of baffle plates, and an inner pipe communicating between adjacent expansion chambers; In an insertion pipe type expansion type exhaust muffler provided with an inlet pipe and an outlet pipe communicating with the expansion chamber, an outward bulging portion is formed on a plate surface of the end plate, and an inner side surface of the end plate is formed. An inward bulging portion facing the bulging portion of the end plate is formed, and a back plate having a through hole formed therein is fixed to the bulging portion, and the bulging portion is provided between the end plate and the back plate. An exhaust muffler, wherein the outlet portion is formed as a gap passage, and an inner pipe communicating with the gap passage is provided. 3. An inner pipe in which a plurality of expansion chambers are defined by a plurality of baffle plates inside a muffler body in which end plates are fixed to both ends of a rectangular cylindrical casing, and an inner pipe communicating between adjacent expansion chambers; In an insertion pipe type expansion type exhaust muffler provided with an inlet pipe and an outlet pipe communicating with the expansion chamber, the end plate is made flat, and an inwardly bulging portion is formed on an inner surface of the end plate. A back plate having a through hole formed in the bulging portion is fixed, the bulging portion is formed as a gap passage between the end plate and the back plate, and an inner pipe communicating with the gap passage is provided. Exhaust muffler characterized. 4. The exhaust muffler according to claim 1, wherein the inner pipe communicating with the gap passage communicates with a gap passage formed between both end plates and a back plate. 5. The exhaust muffler according to claim 1, wherein the inner pipe communicating with the gap passage communicates with a gap passage formed between one end plate and a back plate. 6. The exhaust muffler according to claim 1, wherein a catalyst that communicates between adjacent expansion chambers is disposed in the expansion chamber. 7. The through hole formed in the back plate is a large number of small holes formed by punching.
Exhaust muffler described in.