JPH11182226A - Exhaust muffler for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an output without deteriorating silencing effect. SOLUTION: A first chamber 14, a second chamber 15, and a third chamber 16 are partitioned by first and second partition wall members 12, 13, and exhaust gas flows from the first chamber 14 to the third chamber 16 through the second chamber 15 in order. A first penetrating hole communicated with a space between the first chamber 14 and the third chamber 16, and a second penetrating hole communicated with a space between the second chamber 15 and the third chamber 16, are arranged. Sound wave generated by exhaust gas which flows into the third chamber 16 passing through each penetrating hole collides with each other in the third chamber 16, and they are canceled.

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 motorcycle.

[0002]

2. Description of the Related Art Conventionally, as an exhaust muffler of a motorcycle, a plurality of chambers such as a first chamber, a second chamber, and a third
There are known chambers in which exhaust gas flows in order through each chamber (for example, Japanese Patent Laid-Open No. 7-208).
No. 146).

[0003]

However, in such an exhaust muffler, there is a resistance to the flow of exhaust gas and an exhaust pressure tends to increase in order to achieve a noise reduction effect, so that there is room for improvement in the output surface. is there.

The present invention has been made in view of the above circumstances, and has as its object to provide an exhaust muffler for a motorcycle that has an improved output without impairing the noise reduction effect.

[0005]

According to the first aspect of the present invention, a specific chamber is formed in an exhaust muffler of a motorcycle which is divided into a plurality of chambers by a partition wall member, and the exhaust gas sequentially flows through each of the chambers. A communication passage is formed in each of the two partition wall members, and the sound waves generated by the exhaust gas flowing into the specific chamber through the communication passages collide with each other so as to collide with each other in the specific chamber. Is what is being done.

According to the first aspect of the present invention, by providing the communication passage in the partition wall member, the passage area is enlarged, the flow of exhaust gas is improved, the exhaust pressure is appropriately adjusted, and the output is improved. Is improved. On the other hand, in a specific chamber, sound waves (expansion sounds) due to the exhaust gas ejected from the two communication paths collide with each other and cancel each other, so that the noise reduction effect is not impaired by providing the communication paths.

According to a second aspect of the present invention, in the exhaust muffler for a motorcycle according to the first aspect, one of the communication paths is constituted by a pipe member.

According to the second aspect of the present invention, the length of the pipe member can be adjusted by using one of the communication passages as a pipe member. By adjusting the length of the pipe member, the phase of a sound wave (expansion sound) caused by exhaust gas ejected to a specific chamber through the pipe member (communication passage) is adjusted, and effective noise reduction can be achieved. In this case, as long as the phases of the sound waves generated by the exhaust gas ejected from the two communication passages into the specific chamber are shifted, they cancel each other out and exhibit a sound deadening effect, but the frequencies and amplitudes are equal and the phase is shifted by 180 °. It is most preferable that the superposed acoustic waves cancel each other out and the acoustic waves due to the exhaust gas completely disappear.

According to a third aspect of the present invention, in the exhaust muffler for a motorcycle according to the second aspect, the pipe member is disposed such that an exhaust gas outlet thereof faces an exhaust gas outlet of the other communication passage. .

According to the third aspect of the invention, the sound wave of the exhaust gas ejected from the exhaust gas outlet of the pipe member and the sound wave of the exhaust gas ejected from the exhaust gas outlet of the other communication path collide with each other. As a result, the sound waves cancel each other out, and a sound deadening effect is exhibited.

According to a fourth aspect of the present invention, there is provided the exhaust muffler for a motorcycle according to any one of the first to third aspects, wherein the first chamber and the second
The exhaust gas flows from the first chamber through the second chamber to the third chamber in order from the first chamber through the partition wall member.
A first communication passage communicating between the first chamber and the third chamber;
A second communication passage communicating between the second chamber and the third chamber.

According to the fourth aspect of the present invention, the area of the passage is enlarged by the first and second communication passages, so that the flow of the exhaust gas is improved and the output is improved. On the other hand, in the third chamber, sound waves (expansion sounds) due to exhaust gas ejected from the first communication passage and the second communication passage collide,
Since the sound waves cancel each other out, the sound deadening effect is not impaired.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an exhaust muffler of a motorcycle, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG.
It is sectional drawing in the BB line of FIG.

As shown in FIG. 1, an exhaust muffler 1 according to the present invention is a single muffler of a type provided only for one engine, and is used for a four-cylinder engine (for example, 900 cc) having a high exhaust pressure. An inner cylindrical member 2 (punching plate) in which a number of through holes 2a,... Are formed, and a coaxial cylinder outside the inner cylindrical member 2 via a sound absorbing material 3 (for example, glass wool). And an outer cylinder member 4 disposed on the outer cylindrical member 4. An inlet member 6 having a mounting bolt 5 is provided on one side of the outer cylinder member 4, and an outlet member 7 is provided on the other side.
Are provided respectively. A seal member 8 for preventing exhaust gas from leaking is provided downstream of the inlet member 6. The mounting bolt 5 of the inlet member 6 is
This is for connecting the exhaust muffler 1 to a downstream end of an exhaust pipe (not shown).

A baffle plate 11 composed of a punching plate and first and second partition wall members 12 and 13 are provided in the inner cylindrical member 2 from the side where the inlet member 6 is provided.
Are provided in order. Then, a first chamber 14 is provided between the inlet member 6 and the first partition wall member 12, and a second chamber 15 is provided between the second partition wall member 13 and the outlet member 7. The third chamber 1 is located between the wall member 12 and the second partition wall member 13.
6 are formed separately from each other. Therefore, the baffle plate 11 is provided in the first chamber 14.

Here, the baffle plate 11 is moved to the first chamber 1.
The reason why the exhaust gas passes through the baffle plate 11 is that the exhaust gas passes through the baffle plate 11 because the sound absorbing material 3 provided around the inner cylinder member 2 absorbs higher sounds more easily than low sounds. This is for changing the sound wave of the gas from a low sound to a high sound.

The baffle plate 11 comprises a punching plate as described above, and has a large number of through holes 11a,
Are formed, and a peripheral wall portion 11B extending toward the inlet member 6 in the axial direction from the periphery of the disk portion 11A and attached to the inner peripheral surface of the inner cylindrical member 2.

Like the baffle plate 11, the first partition wall member 12 also has a disk portion 12A and a peripheral wall portion 12B, and extends in three directions from the center of the disk portion 12A as shown in FIG. The convex portion 12a is formed in a curved shape, and a pair of first through holes 12b, 12b (for example, having an inner diameter of 17 .3 mm), and a lower end is provided with a trumpet-shaped first pipe member 21 therethrough. The diameter of the first pipe member 21 is
It is approximately twice the diameter of b and 12b, and approximately １ ／ of the inner diameter of the inner cylindrical member 2.

As shown in FIG. 1, the first pipe member 21 includes not only the first partition wall member 12 but also the third chamber 16.
The second partition wall member 13 also penetrates through the first chamber 1
4 and the second chamber 15 communicate with each other, and the second chamber 15
Exhaust gas is led to the chamber 15.

Similarly to the baffle plate 11 and the first partition wall member 12, the second partition wall member 13
A, and a pair of second second chambers 15A and 13B, which communicate the second chamber 15 and the third chamber 16 to the left and right at an intermediate portion in the vertical direction of the disc 13A, as shown in FIG. Are provided. Second pipe member 2
2 has a smaller diameter than the first pipe member 21. Also,
As shown in FIG. 1, a plurality of through-holes 23a,... Are formed in the center of the upper part of the disk portion 13A, and a tail pipe 23, which is a third pipe member having a trumpet shape at the upstream end, has an inclined axis. It is provided in a state where it is set. More specifically, the tail pipe 23 is provided with an outer pipe 25 shorter than the tail pipe 23 via a sound absorbing material 24 outside the upstream portion thereof, and the outer pipe 25 is attached to the second partition wall member 13. On the other hand, the upstream part of the tail pipe 23 is attached to the outer peripheral side of the inner cylindrical member 2 and the downstream part is inclined so as to be located at the center side of the inner cylindrical member 2.

The tail pipe 23 includes an outer pipe 25
Thus, the downstream portion protrudes more than the upstream portion, and the downstream portion is supported by the outlet member 7,
It constitutes an exhaust gas outlet.

The right and left sides of the tail pipe 23 are shown in FIG.
As shown in FIG. 5, a pair of second through holes 13a, 13a for communicating the second chamber 15 and the third chamber 16 with each other are provided. Here, the second through-hole 13a is connected to the first through-hole 12
The noise reduction effect can be adjusted by shifting the noise reduction effect in the vertical direction from b, but it is considered that the position of the through holes 12b and 13a in the vertical direction and the horizontal direction is the highest in the noise reduction effect.

The outlet member 7 is, as shown in FIG.
A tail cover pipe 31 that covers a downstream portion of the tail pipe 23, and an inner side where one end is connected to the tail pipe 23 and the other end is connected to the inner cylinder member 2 and the outer cylinder member 4 upstream of the tail cover pipe 31. One end is joined to the member 32 and the tail cover pipe 31 and the other end is
2 and an outer member 33 joined to the outer cylinder member 4, and a sound absorbing material 34 is provided in a space between the inner member 32 and the outer member 33. Further, a sound absorbing material 35 is attached to the inner member 32 with an attaching member 36.

With the above-described structure, the first chamber 1 is conventionally used.
4, the second chamber 15 and the third chamber 16 in this order, but in the present invention, the first through-hole 12b
The flow of the exhaust gas from the first chamber 14 to the third chamber 16 through the second chamber 15 and the flow of the exhaust gas from the second chamber 15 to the third chamber 16 through the second through hole 13a are allowed. Has improved air permeability, and output can be improved.

Exhaust gas (expansion noise) is ejected from the first chamber 14 through the first through hole 12a to the third chamber 16 and exhaust gas (expansion noise) is emitted from the second chamber 15 through the second through hole 13a. ) Is ejected into the third chamber 16, so that the third
In the chamber 16, sound waves (expansion sounds) due to the exhaust gas collide and interfere with each other, so that they cancel each other out and are muffled, and the first and second through holes 12b, 13 are formed.
The reduction of the sound deadening effect due to the provision of a is avoided. This is based on the fact that when sound waves having the same frequency and amplitude and a phase difference of 180 ° overlap with each other, they cancel each other out and disappear.

In the above embodiment, the baffle plate 11 is provided in the first chamber 14, but a honeycomb catalyst 41 may be provided as shown in FIGS. In this case, in the exhaust muffler 1A, the first through hole 1
2b, a pipe member 42 is penetrated so that the center of the pipe member 42 coincides with the center of the second through hole 13a, that is, the exhaust gas outlet of the pipe member 42 is connected to the second through hole 13a. (Exhaust gas outlet). In this case, the honeycomb catalyst 41 becomes resistance and the output tends to decrease, which is particularly effective.

Here, by changing the length of the pipe member 42, the phase of the sound wave generated by the exhaust gas can be adjusted.
A desired silencing effect can be obtained. In the case of this example, the inner diameter of the pipe member 42 is 17.2 mm and the outer diameter is 19.
Although it is 2 mm, it is a matter of course that the present invention is not limited to this. 4 to 6, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0029]

The present invention is embodied in the form described above, and has the following effects.

According to the first aspect of the present invention, since the communication passage is provided in the partition wall member, the passage area can be enlarged, the flow of exhaust gas can be improved, the output can be improved, and the specific chamber can be improved. In this configuration, the sound waves (expansion sound) generated by the exhaust gas ejected from the two communication passages are made to collide with each other, so that the sound waves are canceled each other.
Therefore, the output can be improved without deteriorating the muffling effect.

According to the second aspect of the present invention, since one of the communication passages is constituted by a pipe member, by changing the length of the pipe member, an acoustic wave generated by exhaust gas ejected to a specific chamber through the one communication passage is formed. By adjusting the phase of the (expansion sound), a desired silencing effect can be obtained.

According to the third aspect of the present invention, since the exhaust gas outlet of the pipe member is opposed to the exhaust gas outlet of the other communication path, the sound emission effect can be effectively exerted by the collision of sound waves caused by the exhaust gas. it can.

According to a fourth aspect of the present invention, a first communication passage communicating between the first chamber and the third chamber and a second communication passage communicating between the second chamber and the third chamber are provided. Since the first and second communication passages are provided, the passage area of the exhaust gas can be enlarged, the flowability of the exhaust gas can be improved, the output can be improved, and the third chamber can be improved. In the above, the sound waves generated by the exhaust gas from the first communication path and the second communication path collide with each other to cancel the sound waves, so that the sound deadening effect is not impaired.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an exhaust muffler of a motorcycle according to the present invention.

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

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

FIG. 4 is a diagram similar to FIG. 1 for another embodiment.

FIG. 5 is a sectional view taken along line CC of FIG. 4;

FIG. 6 is a sectional view taken along line DD of FIG. 4;

[Explanation of symbols]

 Reference Signs List 1 exhaust muffler 1A exhaust muffler 12 first partition wall member 12b first through hole 13 second partition wall member 13a second through hole 14 first chamber 15 second chamber 16 third chamber 42 pipe member

Claims (4)

[Claims] 1. An exhaust muffler for a motorcycle, which is divided into a plurality of chambers by a partition wall member, and exhaust gas flows through each of the chambers in order, and a communication passage is formed in each of two partition wall members forming a specific chamber. An exhaust muffler for a motorcycle, wherein the exhaust muffler is formed so that sound waves generated by exhaust gas flowing into the specific chamber through the communication paths collide and cancel each other in the specific chamber. 2. The exhaust muffler for a motorcycle according to claim 1, wherein one of the communication passages is formed of a pipe member. 3. The exhaust muffler for a motorcycle according to claim 2, wherein the pipe member is disposed such that an exhaust gas outlet thereof faces an exhaust gas outlet of the other communication passage. 4. An exhaust gas is divided into a first chamber, a second chamber, and a third chamber by a partition wall member, and exhaust gas flows from the first chamber to the third chamber via the second chamber in order. A first communication passage communicating between the chamber and the third chamber;
The exhaust muffler for a motorcycle according to any one of claims 1 to 3, further comprising a second communication passage communicating between the second chamber and the third chamber.