JPH0143133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silencer for a motorcycle, and more specifically, a silencer body having two outer shells fixed to each other and formed into an elongated shape in the front and back direction is arranged in the front and rear direction by partitions. divided into multiple compartments,
An exhaust pipe is connected to a differential user pipe arranged in the front-rear direction in a first compartment located at the forefront, and exhaust from the engine is guided into the first compartment through the differential user pipe, and then the exhaust pipe is connected to the outside. The present invention relates to a silencer for a motorcycle that discharges air into the air.

Generally, the exhaust gas discharged from the engine is always accompanied by pressure fluctuations, and when the exhaust gas is led into the interior of the muffler body, the muffler itself vibrates due to the pressure fluctuations in the exhaust gas, causing a so-called "siel sound" to be heard outside. emit noise. One way to suppress this noise is to increase the rigidity of the silencer by attaching a special reinforcing member to the main body.

The present invention makes effective use of the diffuser pipe by forming a part of the diffuser pipe, which is indispensable for this type of muffler, from a part of one of the outer shells that constitute the muffler main body. In addition to increasing the rigidity of the silencer body and suppressing the occurrence of shell noise,
To eliminate the complexity of assembling a diffuser pipe, to reduce the weight of a silencer, and to enhance the silencing effect by omitting a special support member for supporting the diffuser pipe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the drawings. FIGS. 1 and 2 show an example of a motorcycle silencer (hereinafter simply referred to as a silencer) according to the present invention. The muffler main body 10 of this muffler has two left and right parts.
The muffler has two outer shells 11 and 12 that are elongated in the front-rear direction, and a diffuser pipe 21, a discharge pipe 22, and four partitions 31 to 34 are arranged inside the muffler main body 10.

Both outer shells 11 and 12 are provided with flange portions 11a and 12a facing each other around the entire periphery of their openings, and these flange portions 11a and 12a are seam welded with each other pressed against each other. , constitutes a muffler main body 10 having a through hole 10a through which the connecting pipe 23 passes through at the front end and a through hole 10b through which the discharge pipe 22 penetrates at the rear end. Of these two outer shells 11 and 12, a plurality of overlapping wire meshes 13 are welded to the inner wall surface of the left outer shell 11 at the upper front part thereof, as shown in FIGS. 2 and 3.
As shown in the drawings and FIG. 5, a punching metal 14 that holds a sound absorbing material such as glass wool or asbestos is welded approximately at the center thereof. In addition, the right outer shell 12
As shown in FIGS. 2, 3, and 5, punching metals 15 and 16 are welded to the front and substantially central portions of the inner wall surface of the drum to hold the sound absorbing material therebetween, respectively.

On the other hand, on the inner wall surfaces of both outer shells 11 and 12, a first partition 31, a second partition 32, and a third partition are formed as shown in FIG. 2 and FIGS.
A partition 33 is welded across both outer shells 11 and 12. Each of these partitions 3
1 to 33 have annular flange portions 3 on their outer peripheries.
1a to 33a, and both outer shells 11 and 1
It is welded to the inner wall surface of 2. Further, the fourth partition 34 has flange portions 34 projecting upward on both sides, as shown in FIGS. 2, 6, and 7.
a, 34b, and has a first partition 31 and a second partition 32.
It is welded to each flange part 31a, 32a. As a result, each of the partitions 31 to 34 divides the inside of the silencer main body 10 into four compartments R ₁ to R ₄ arranged in the front and back direction, and discharges the air to the second partition 32 and the third partition 33. Pipes 22 pass through and are welded to each other. The distal end of the discharge pipe 22 is formed to have a slightly constricted small diameter, and the rear end has a large number of through holes 22a.
is formed. The distal pipe 22 has a distal end that opens into the third compartment _R3 , a rear end that opens to the outside, and a portion where the through hole 22a is formed is located in the fourth compartment _R4. . The fourth compartment _R4 is filled with glass wool, asbestos, etc., and has a sound absorbing function.

In this muffler, an exhaust pipe (not shown) connected to an exhaust port of the engine is connected to a diff user pipe 21 via a connecting pipe 23, and exhaust from the engine is passed through the diff user pipe 21 to the inside of the muffler main body 10. and is discharged to the outside through the discharge pipe 22. In other words, the exhaust goes first to the diffuser pipe 2.
1 into the first compartment R ₁ and through the passage P into the second compartment R ₂ , and then through the openings 32 b and 32 provided in the second partition 32 .
c to the third compartment _R3 , and finally exhausted to the outside through the discharge pipe 22. During this time,
The exhaust gas undergoes repeated expansion, diffusion, contraction, resonance, etc. to be muffled, cooled, and discharged to the outside.

However, the differential user pipe 21 is shown in Fig. 2~
As shown in FIG. 5, a half-cylindrical member 21a is bent from the front end of the muffler main body 10 to approximately the center and extends in the front-rear direction. It is formed by welding to the inner wall surface of the left outer shell 11, and the semi-cylindrical member 21a and a portion 21d of the left outer shell 11 are the main constituent members. Note that, as shown in FIGS. 1 and 5, a flat plate supplementing a part of the inner wall surface of the left outer shell 11 is provided on the inner wall surface of the left outer shell 11 that forms the most reduced part of the silencer main body 10. A shaped member 21e is welded. This flat member 21e extends from the most contracted portion of the muffler main body 10 to the rear bulging portion, and the rear end portion of the semi-cylindrical member 21a is welded. Therefore,
The flat member 21e serves as an auxiliary member constituting the diffuser pipe 21.

As best shown in FIG.
The rear portion of the semi-cylindrical member 21a is bulged outward from near the rear end thereof. As a result, the rear end of the diffuser pipe 21 opened rearward is located so as to discharge exhaust gas along approximately the center of the rear cross section of the first compartment _R1 , and
It faces the first partition 31 forming the rear wall of _R1 .

In the silencer configured in this way, the semi-cylindrical member 21a is welded to the inner wall surface of the left outer shell 11 constituting the silencer main body 10.
Since the left outer shell 11 and the muffler main body 10 are indispensable to this type of muffler, and a long diffuser pipe 21 is formed by a portion 21d of the left outer shell 11. The pipe 21 increases the rigidity, and can sufficiently suppress the occurrence of shell noise caused by pressure fluctuations in the exhaust gas. Therefore, according to the muffler, no other reinforcing member corresponding to the semi-cylindrical member 21a of the diffuser pipe 21 is required in order to suppress the generation of shell noise from the muffler main body 10. Further, since there is no need for any special support member to support the differential user pipe 21 within the silencer body 10, the complicated assembly work of the differential user pipe 21 is eliminated, and
It is also possible to reduce the weight of the muffler.

Further, the rear end of the diffuser pipe 21 opened toward the rear is located so as to discharge exhaust gas along approximately the center of the rear section of the first compartment _R1 .
Since it faces the partition 31, the exhaust gas from the engine is discharged from the rear end of the diffuser pipe 21 without encountering resistance, and when it hits the first partition 31, it is uniformly distributed in the first compartment _R1 . After being expanded, it is guided through the passage P to the second compartment _R2 . This reduces the resistance to discharge from the diffuser pipe and improves the silencing effect. In addition,
In motorcycle silencers, recesses are usually provided in the outer shells 11 and 12 to avoid contact with various parts of the vehicle body, but the rear part of the semi-cylindrical member 21a is formed in the left outer shell 11. It is attached using the formed recess, and there is no need to provide it specially.

Note that this embodiment shows an example of the present invention, and in the present invention, the shapes of the outer shells 11 and 12, the diffuser pipe 21, and the discharge pipe 22, and the shapes of each of the parts arranged in the silencer main body 10 are Partition 3
1 to 34, and the shape and number of each compartment R ₁ to _{R 4} formed in the silencer main body 10,
It can be changed as appropriate depending on the desired muffler function, and when changing, please use the diffuser pipe 2.
The semi-cylindrical member 21a constituting the
It may be fixed to any of the inner wall surfaces of 2. In short, the present invention has two outer shells fixed to each other to form a muffler main body elongated in the front-rear direction, and partitioned into a plurality of compartments arranged in the front-rear direction by partitions, the muffler body being located at the forefront. An exhaust pipe is connected to a differential user pipe arranged in the front and back direction within the first compartment, and exhaust gas from the engine is guided into the interior of the first compartment through the differential user pipe and then exhausted to the outside. This can be implemented in various types of motorcycle silencers.

As explained above, the present invention provides the various types of motorcycle silencers described above, in which a semi-cylindrical member is fixed to the inner wall surface of either one of the two outer shells. The diffuser pipe is formed with a part of the one outer shell, and the rear part bulges outward from near the rear end of the semi-cylindrical member of the one outer shell, and is opened rearward. Exhaust gas is discharged from the rear end of the diffuser pipe along approximately the center of the rear cross section of the first compartment, and
Its structural feature lies in the fact that it is positioned so as to face the partition forming the rear wall of the compartment. Therefore, according to the present invention, the rigidity of the muffler body is increased by effectively utilizing the diffuser pipe, which is indispensable to this type of muffler, thereby suppressing the generation of cries from the muffler body. In addition, the differential user pipe can be placed inside the silencer body without the need for a special support member, eliminating the complicated assembly work of the differential user pipe and reducing the weight of the silencer. You can also aim for Also,
Exhaust gas from the engine is discharged from the rear end of the diffuser pipe without resistance, and spreads uniformly into the first compartment when it hits the partition, reducing the exhaust resistance and further improving the noise reduction effect. do.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway plan view showing an example of a silencer according to the present invention, Fig. 2 is a partially longitudinal side view of the same with the left side outer shell removed, and Fig. 3 is a -
Figure 4 is a vertical cross-sectional view taken along the - line in Figure 2, Figure 5 is a vertical cross-sectional view taken along the - line in Figure 2, and Figure 6 is a vertical cross-sectional view taken along the - line in Figure 2. 7 is a longitudinal sectional view taken along the - line in FIG. 2, and FIG. 8 is a longitudinal sectional view taken along the - line in FIG. 2. Explanation of symbols, 10... Silencer body, 11, 12...
Outer shell, 21... diffuser pipe, 21a... semi-cylindrical member, 22... discharge pipe, 31-34... partition, _R1 ... first compartment.

Claims (1)

[Claims] 1. A silencer main body formed into an elongated shape in the front-rear direction by fixing two outer shells to each other is divided into a plurality of compartments arranged in the front-rear direction by partitions,
An exhaust pipe is connected to a differential user pipe arranged in the front-rear direction in a first compartment located at the forefront, and exhaust from the engine is guided into the first compartment through the differential user pipe, and then the exhaust pipe is connected to the outside. In the silencer for a motorcycle, a semi-cylindrical member is fixed to the inner wall surface of one of the two outer shells, and the semi-cylindrical member and a part of the one outer shell are connected to each other. The diffuser pipe is formed by the above, and the rear portion of the semi-cylindrical member of the one outer shell is bulged outward from near the rear end of the semi-cylindrical member, so that the diffuser pipe is opened rearward. The automatic vehicle is characterized in that its rear end is positioned so as to face the partition that discharges exhaust gas along substantially the center of the rear cross section of the first compartment and forms the rear wall of the first compartment. Silencer for motorcycles.