JPH011681A - motorcycle exhaust system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of LR Industry 7) The present invention relates to an exhaust system for a motorcycle equipped with a multi-cylinder engine, and more specifically to one in which a pair of mufflers are provided on one side of the vehicle body.

(Prior Art) An example of an exhaust system for a motorcycle equipped with a multi-cylinder engine is disclosed in Japanese Utility Model Publication No. 10412/1983. According to this, the exhaust system has an exhaust pipe extending from the exhaust hole of the cylinder toward the rear of the vehicle body, and a plurality of mufflers located further behind the exhaust pipe, and these mufflers are located on both sides of the vehicle body. They are distributed and arranged. Also,
In order to improve the silencing effect, the extending end of the exhaust pipe and
An exhaust chamber (corresponding to the reference numeral 5 in the above publication) is interposed between the front end of each muffler.

(Problem to be Solved by the Invention) Incidentally, in the case of the above configuration, the exhaust chamber and the muffler are provided so as to be continuous in the longitudinal direction of the vehicle body, so the overall length of both of them is determined by the dimensional balance with the vehicle body. There is a risk that it will become too long. If the length is too long, the appearance of the motorcycle as a whole deteriorates, which is a problem.

(Objective of the Invention) This invention was made in view of the above-mentioned circumstances, and aims to shorten the overall length of the exhaust system in the longitudinal direction so as to obtain a preferable balance in terms of dimensions with respect to the vehicle body. The purpose of this is to improve the appearance of the motorcycle.

(Structure of the Invention) A feature of the present invention for achieving the above object 1 is that a pair of mufflers are provided on one side of the vehicle body, and an exhaust channel is provided closer to the vehicle body than the mufflers in the vehicle width direction. established,
The interiors of both mufflers and the exhaust channel are made to communicate with each other, and a pair of exhaust pipes are extended toward the rear of the vehicle from the exhaust holes of the cylinders, with the extending end of one of the exhaust pipes being connected to one side. After fitting into the front end of the muffler, the exhaust pipe is made to face the inside of the exhaust chamber, and the extending end of the other exhaust pipe is fitted into the 1111 end of the other muffler, and then the exhaust pipe is passed through the inside of the one muffler, and then the It is located at a point facing into the exhaust chamber.

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

In FIG. 2, ■ indicates a motorcycle, and arrow Fr indicates the front of the vehicle body. The motorcycle 1 has a body frame 2 having a so-called diamond shape. A front wheel 4 is supported at the front part of the body frame 2 by a front fork 3. On the other hand, at the rear part of the body frame 2, a rear arm 7 is supported by a pivot shaft 6 so as to be vertically swingable. The moving end supports the rear wheel 8.

Further, an engine 9 is supported on the vehicle body frame 2. This engine 9 is a multi-cylinder engine having a front cylinder lO and a rear cylinder 11, and these cylinders 10 and 11 are connected to a crankcase 13 so as to form a square shape when viewed from the side. The engine 9 drives the rear wheels 8 to cause the motorcycle l to travel.

In addition, 14 is a handle, 15 is a fuel tank, 16 is a seat, and 17 is a shock absorber.The rear lower end of the vehicle body frame 2 is pivoted on a main stand 18 so as to be movable up and down.

An exhaust system 20 is provided for the engine 9. This exhaust device 20 has an upper muffler 21 and a lower muffler 22 located above and below, which have substantially the same shape as each other, and
They are the same size and are located on the right side of the rear of the vehicle. Further, in the vehicle width direction, an exhaust chamber 23 made of sheet metal is provided closer to the vehicle body than both mufflers 21 and 22, and this exhaust chamber 23 is located on the lower surface side of the rear portion of the vehicle body frame 2.

On the other hand, a front exhaust pipe 25 extends toward the rear of the vehicle body from the exhaust hole of the front cylinder 10, and a rear exhaust pipe 26 extends toward the rear of the vehicle body from the exhaust hole of the rear cylinder 11. L
-C0,6° The front ends of the two mufflers 21, 22 mentioned above, the exhaust chamber 23, and the extending ends of the exhaust pipes 25, 26 are in communication with each other, and each cylinder 10, 11 The exhaust from the exhaust pipes 25, 26, the exhaust chamber 23,
81N passes through each muffler 21, 22 and is discharged to the rear of the body.

-5. According to Fig. 1 and Figs. 3 to 5, the exhaust system 20
The configuration will be explained in more detail.

A through hole 27 is formed on the lower surface of the front end of the upper muffler 21, and the through hole 27 communicates the inside and outside of the upper muffler 21. In addition, an exhaust chamber 23 is formed at the front end of the lower muffler 22.
A front through hole 28 and a rear through hole 29 are formed in front and back on the surface facing the lower muffler 2.
It connects the inside and outside of 2. In addition, each muffler 21.
22 and the right side of the exhaust chamber 23 is provided.
The through holes 27, 28, 29 communicate with the inside of the exhaust chamber 23.

The extending end of the front exhaust pipe 25 is fitted into the front end of the lower muffler 22 coaxially with the front end of the lower muffler 22, and furthermore, the extending end is bent toward the exhaust chamber 23 and It passes through the through hole 28 and faces into the exhaust chamber 23.

Further, the extending end of the rear exhaust pipe 26 is fitted into the front end of the upper muffler 21 coaxially with the front end of the upper muffler 21 , is bent toward the exhaust chamber 23 , and is further passed through the through hole 27 . and extends into the exhaust chamber 23. In this case, the portion of the rear exhaust pipe 26 from the point where it passes through the through hole 27 to the inside of the exhaust chamber 23 crosses the rear through hole 29, that is, passes through the inside of the lower muffler 22. Therefore, the volume of the lower muffler 22 is smaller than that of the upper muffler 21 by the amount that the rear exhaust pipe 26 passes through the lower muffler 22. Therefore, both mufflers 21 and 22 attenuate the energy of sound waves having different frequencies.

Also, as mentioned above, the rear exhaust 'i? 26 is the through hole 27
The part from where it penetrates through to the inside of the exhaust chamber 23 passes through the inside of the lower muffler 22, that is, here, the rear exhaust pipe 26 and the lower muffler 22 partially intersect with each other and are overlapped one above the other. For this reason, the vertical dimension of this portion is reduced by the size that has been matched in this way. In this embodiment, the space in which the rear arm 7 swings up and down is expanded by utilizing the reduced vertical dimension. That is,
A recess 32 is formed on the upper surface of the connecting portion between the exhaust chamber 23 and the connecting pipe 31 at a position corresponding to the overlapping portion of the rear exhaust pipe 26 and the lower muffler 22, and the rear arm 7 is placed above the recess 32. By locating the rear arm 7, the vertical movement dimension of the rear arm 7 can be made sufficiently large.

Note that the left end of the exhaust chamber 23 is connected to the left bracket 3.
4 is supported by the vehicle body frame 2. Further, the L muffler 21 and the connecting vibe 31 are supported by the right bracket 35 on the two-body frame 2, and thereby both the mufflers 21, 22 and the exhaust chamber 23 are supported on the body frame 2.

Next, with particular reference to FIG. 1, the flow of exhaust gas according to the above configuration will be explained. The exhaust gas from the front cylinder 10 passes through the front exhaust pipe 25 and flows into the exhaust chamber 23 as shown by arrow A in the figure. Next, this exhaust gas flows into the upper muffler 21 through the through hole 27 as shown by arrow B in the figure, and is discharged from the rear end.

At the same time, it also flows into the lower muffler 22 through the front through hole 28 and the rear through hole 29, as indicated by arrows c and c' in the figure, and is discharged from the rear end.

The energy of the sound waves in the exhaust gas is attenuated when passing through the exhaust chamber 23 and both mufflers 21 and 22, thereby reducing exhaust noise. In this case, since the volumes of the mufflers 21 and 22 and the exhaust chamber 23 are different from each other, the energy of sound waves having different wave numbers is attenuated by these. Therefore, noise in the exhaust gas can be effectively prevented.

On the other hand, the exhaust from the rear cylinder 11 passes through the rear exhaust pipe 26 and flows into the exhaust chamber 23 as shown by the arrow in the figure. Next, this exhaust gas, like the exhaust gas from the front cylinder 10, is discharged through each muffler 21, 22 as shown by arrows B, C, and C'' in the figure.

(Effects of Examples) According to the second embodiment, the following effects can be obtained. That is, the exhaust channel/to 2 is located closer to the body frame 2 than the mufflers 21 and 22.
3 are arranged, and a pair of upper and lower mufflers 21 and 22 are provided. For this reason, since the vertical dimensions of the single muffler 21.22 are increased to some extent, the appearance of the exhaust chamber 23 is effectively suppressed by the double muffler 21.22. Therefore, in reality, the exhaust chamber 23
Although the provision of the mufflers 21 and 22 provides a sufficient noise reduction effect, it is possible to suppress the presence of the exhaust chamber 23 and make both the mufflers 21 and 22 stand out in terms of appearance.
This is beneficial in improving the appearance of the motorcycle l.

(Effect of the invention) According to the invention, a muffler is provided on one side of the vehicle body, and
Because the exhaust chamber is provided closer to the vehicle body than this muffler in the vehicle width direction, compared to conventional systems where the muffler and exhaust chamber are connected in the longitudinal direction of the vehicle body, the overall length of both is longer. Dimensions become shorter. Therefore, when comparing the dimensions of the exhaust system and the vehicle body, it is possible to obtain a favorable balance between the two in terms of appearance.

In addition, the extending end of each exhaust pipe extending toward the rear of the vehicle body is fitted into the +i77 end of the corresponding muffler and then faces into the exhaust channel μ, so each exhaust pipe looks as if it is connected directly to the muffler. It will be done. Therefore,
X1 from the exhaust pipe to the muffler! A continuous flowing shape is obtained, which is extremely beneficial for motorcycles where a sporty appearance is desired.

Furthermore, in this invention, a portion from the position where the exhaust pipe is inserted into the muffler to the exhaust chamber passes through the inside of the other muffler to narrow the volume of this muffler, so both mufflers appear to have the same size. Even if the mufflers have the same shape, the volumes inside the two mufflers can be made different using the exhaust pipe. In other words, by doing this, both of these mufflers will attenuate the energy of sound waves having different frequencies from each other, and therefore, with a simple configuration that uses part of the exhaust pipe, noise in the exhaust gas can be effectively reduced. will be exposed.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which FIG. 1 is a partial cutaway plan view of the entire exhaust system, FIG. 2 is a side view of the entire motorcycle, and FIG. 3 is a partially enlarged partial cutaway view of FIG. 2. Fig. 4 is a sectional view taken along the rV-ff line in Fig. 1, and Fig. 5 is a sectional view taken along the line V-V in Fig. 1.
It is a sectional view taken along the line. 1. Motorcycle, 2. Body frame (vehicle body), 9.
・Engine, lO・・Front cylinder, 11・・Rear cylinder, 2
0... Exhaust system, 21... Upper muffler (other muffler),
22. Lower muffler (one muffler), 23."fl1%
Chang/<, 25・Pre-exhaust pipe (one exhaust pipe), 26
...Rear exhaust pipe (other exhaust pipe).

Claims (1)

[Claims] 1. In a motorcycle equipped with a multi-cylinder engine, a pair of mufflers is provided on one side of the vehicle body, and an exhaust chamber is provided closer to the vehicle body than these mufflers in the vehicle width direction, and each internal part of both mufflers and the exhaust chamber is provided. make them communicate with each other,
A pair of exhaust pipes extends toward the rear of the vehicle body from the exhaust hole of the cylinder, and the extending end of one of the exhaust pipes is fitted into the front end of one of the mufflers, and then faces into the exhaust chamber; An exhaust system for a motorcycle, characterized in that the extending end of the other exhaust pipe is fitted into the front end of the other muffler and then passed through the one muffler before facing into the exhaust chamber.