JPS595824A - Exhaust silencing apparatus for motorcycle - Google Patents

Abstract

PURPOSE:To simplify the noise absorbing structure and to reduce the exhaust vibration, by disposing a silencing material radially outwards of the opening of an inner tube with a proper spacing from the tube, and discharging exhaust gas into a chamber from openings at the opposite ends of the silencing material. CONSTITUTION:Exhaust gas, introduced into an inner sleeve section 16a of a silencer tube 16 via exhaust pipes 22, 22 connected to respective cylinders and divided to the right and left by a partition plate 18, is carried radially outwards and then into a passage 19 through holes 16a' formed in the inner sleeve section 16a'. While the exhaust gas passes through the passage 19, vibrational wave of exhaust gas, i.e., exhuast noise is absorbed when it passes through noise absorbing holes 16b' and is scattered toward a noise absorbing material 20. Thereafter, the exhaust gas is discharged into an expansion chamber 21a from openings 19a at the opposite ends of a middle sleeve section 16b communicated with the passage 19 and is expanded in the chamber 21a, so that the temperature and pressure of the exhaust gas are lowered and the vibrational wave of exhaust gas is attenuated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust silencing device for a motorcycle, in particular,
The present invention relates to an exhaust muffling device for a motorcycle, which is equipped with a bristle tube equipped with a muffling cylinder.

In general, in a motorcycle, high-temperature, high-pressure exhaust discharged from the engine passes through an exhaust pipe and a muffler connected to the exhaust pipe, and is reduced to a low temperature and low pressure, and then is discharged to the outside air at the side of the rear wheel.

For this reason, various proposals regarding exhaust muffling devices have been made in the past. For example, a chamber is provided to collect exhaust gas from each cylinder of the engine upstream of the muffler,
After attenuating the vibration waves of the exhaust, it is discharged from the muffler. However, when trying to make the vehicle body more compact, the space for arranging the chamber is naturally limited, so the chamber has to have a small capacity and it is difficult to achieve a sufficient sound deadening effect. In this case, the exhaust vibration waves are generally reduced by increasing the size of the muffler or by attaching a vibration absorbing material such as glass wool to the inner surface of the chamber, but this has the disadvantage of complicating the structure.

The present invention has been made in view of the above points, and aims to reduce exhaust vibration without complicating the sound absorption structure of the chamber. , a chamber communicating with the muffler, left and right exhaust introduction pipes for introducing exhaust gas from the engine, and '5I.
: In the exhaust silencer for a motorcycle, an inner cylindrical pipe communicating with the left and right exhaust introduction pipes is disposed in the chamber, an opening is provided on the outer periphery of the inner cylindrical pipe, and a gap is provided outside the opening in the radial direction. 7. To provide an exhaust muffling system for a motorcycle, wherein a cylindrical muffling material is provided and supported, and the exhaust gas is discharged into the chamber through opening gaps on the outer periphery of both ends of the muffling material. .

Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4.

FIG. 1 shows a state in which a motorcycle having an engine 1 mounted in the center of a vehicle body F and a front wheel 2 and a rear wheel 4 mounted on the front and rear parts of the vehicle body F is equipped with the exhaust silencer of the present invention. There are mufflers 1 on both sides of the rear wheel 4.
5 is arranged, and a Channo (11) is arranged in the space behind the engine 1 and in front of the rear wheel 4.
1 is disposed below #t #Y of the swing arm 14 between approximately below the pivot shaft 12' attached to the frame 12 and the rear wheel 4, and is attached between the mufflers 15 and 15. And Channoku 11 is engine 17
5) It communicates with the cylinder exhaust pipes 22, 22 and the upstream portion of the muffler 15.

The explanation will be further continued based on FIGS. 2 to 4. The chamber 11 has a substantially cylindrical shape with both ends open, and bulges 11α and 11a are formed facing both ends on the rear wheel 4 side and protrude to the extent that they do not contact the rear wheel 4.
We are trying to increase the internal volume of 1. Also, Channo (11
A muffling tube 1675Z, which serves as an exhaust gas introduction pipe to the chamber 11, is fitted into the internal shaft in a direction perpendicular to the vehicle body F, and is clamped and fixed at both ends by fixing members 17.17.

The muffler cylinder 16 is composed of an inner cylinder part 16α, a middle cylinder part 16b, and an outer cylinder part 16C. The cylindrical portion 16α is cylindrical,
Its both ends are open, and a large number of open ventilation holes 16α' are provided on its circumferential surface. I inner cylinder part 1
6α can be easily formed into a porous cylindrical shape by molding a pinching plate. A partition plate 18 is provided at the center of the inner cylindrical portion 16a. The middle cylindrical portion 16h
is a hollow cylinder with both ends open, and a large number of sound absorbing holes 16h' through which exhaust vibration waves pass are bored at appropriate positions on the curved surface. The middle cylindrical portion 16A is arranged concentrically with the inner cylindrical portion 16α, and the annular attachment is fixed to the inner cylindrical portion 16α by a member 60. The outer cylindrical portion 16C is a hollow cylinder, and has a diameter larger than the diameter of the middle cylindrical portion 16b from the center to the vicinity of both ends, and the diameter gradually decreases at both ends until it touches the outer surface of the middle cylindrical portion 16b at both ends. It is worn.

An appropriate number of partition walls 6 are provided between the inner cylinder part 16α and the middle cylinder part 16b.
1 is arranged. An opening 19α is defined by the inner cylindrical portion 16α, the middle cylindrical portion 16h, and the partition wall 61 (see FIG. 4),
The passage groove 19 guides the exhaust gas flowing in from the vent hole 16α' toward the openings at both ends of the muffling cylinder 16. In addition, the middle cylinder part 1
The space formed by the outer cylinder part 6b and the outer cylinder part 16C is filled with a sound absorbing material 20 made of glass wool.

A muffler 15 communicates with the space 21α defined by the inner surface of the chamber 11 and the outer surface of the muffler 16 through a communication port 17α provided in the fixing member 17.
．． 15 front compartment 21h.

A chamber expansion chamber 21 consisting of 21h is provided. Inside the front compartments 21h and 21A, cylinder exhaust pipes 22.22 extend in a substantially L-shape from the tips of the mufflers 15 and 15 toward the chamber 11.
It is connected to both ends of the internal cylinder 16α of No. 6. Further, these front compartments 2 are provided on the downstream side of the front compartments 21b and 21A.
A porous cylindrical exhaust passage 25.25 communicating with the exhaust passages 1A and 21b is provided, and a resonance chamber 23.23 is provided on the outer periphery of this exhaust passage 25.25.
An outlet chamber 26 having approximately the same diameter as the diameter of the outlet chamber 26 is formed, and an inner cap 24, 24 is disposed inside the outlet chamber 26. The outlet chamber 26.26 is connected to the muffler 15 so as to be discharged from the outer periphery of the end of the muffler 15.15 to the atmosphere by the inner cap 24.
．． 15 to the downstream end. In addition, the chamber 11
As shown in FIG. 6, the upper half body 11C and the lower half body 11d' are assembled by joining together at a mating surface 11.6. And muffler 15゜15 is a muffler bracket fixed to this)
15'.

15′? It is attached to a predetermined location of the frame 12 via a fixing means (not shown).

In the above configuration, the exhaust gas in a high temperature and high pressure state from each cylinder of the engine (not shown) flows as indicated by the arrow in the figure and is introduced into the inner cylinder part 16α of the silencer cylinder 16 through the cylinder exhaust pipe 22.22. The left and right exhaust gases are separated into the outer periphery by the partition 1fyis and reach the passage groove 19 via the vent hole 16α' of the inner cylinder portion 16a. Exhaust air flows through this passage groove 19. While passing through the sound absorption hole 16b, exhaust vibration waves, that is, exhaust sound, especially high-energy sound with many high-frequency components, pass through the sound absorption hole 16b.
"e passes through, is radiated toward the sound absorbing material 20, and is absorbed. Next, the exhaust gas that has been discharged and expanded from the openings 19α at both ends of the middle cylinder portion 16b communicating with the passage groove 19 into the chamber expansion chamber 21 is As the temperature and pressure decrease, the exhaust vibration waves are attenuated.Furthermore, while passing through the muffler exhaust path 25, the exhaust vibration waves are canceled out and attenuated by the resonance waves generated in the resonance chambers 23 and 23, and at the same time, the exhaust pressure t: Decrease.

As a result, the flow velocity of the exhaust gas is reduced, and the noise caused by the exhaust flow is reduced.

Further, FIG. 5 is a plan view showing a second embodiment of the present invention. The second embodiment differs from the first embodiment in the configuration related to the cylinder exhaust pipe 22.22 and the muffler exhaust passage 25.25.

In Figure 5, cylinder exhaust '! 22', 22Tj:
, one end is opened on the upstream side of a muffler expansion chamber 32.62 provided at the front of the muffler 15.15 without being connected to the inner cylinder portion 16α of the muffler 16. The muffler expansion chamber 32.32 communicates with the openings 16d at both ends of the internal cylinder 16α of the muffler cylinder 16. In addition, muffler exhaust path 2
5' and 25' are L-shaped, and are resonance chambers 23.23.
It extends into the chamber 11 from the upstream side of the chamber 11 and communicates with a space defined by the inner surface of the chamber 11 and the outer surface of the muffler 16, that is, the chamber expansion chamber 21'. Other configurations are
Since this is the same as the first embodiment, the explanation will be omitted.

In the above configuration, the high temperature and high pressure exhaust from the cylinder (not shown) is discharged into the muffler expansion chamber 32, 32 through the cylinder exhaust pipes 22', 22' and expands, and the temperature and pressure decrease, and at the same time Exhaust vibration waves are attenuated. Next, the exhaust gas is introduced into the inner cylinder portion 16α of the muffling tube 16.

After this, the process is the same as in the first embodiment described above, except that the exhaust from the chamber expansion chamber 21' is immediately discharged to the muffler exhaust passage 25' without passing through the front compartment 21h' shown in FIG. Since there is, I will omit the explanation. According to the second embodiment, the exhaust gas that has been reduced in temperature and pressure in the muffler expansion chamber 62.32 is introduced into the muffler tube 16, so that the durability of the muffler tube 16 is improved compared to the first embodiment. . Similarly, in each of the above-described embodiments of the present invention, the partition plate 18 has a function of facilitating the flow of exhaust gas into the passage groove 19 via the vent hole 16α' of the internal cylinder 16α. Exhaust pipe 22.2
2(, Rirui is 22'.

The explosion stroke of the engine's cylinders connected to the left and right cylinder exhaust pipes 22.22 (or 22').

22'), the exhaust gas discharged into the chamber 11 for each cylinder exhaust pipe 22 (or 22') is replaced by a silencer cylinder provided on the outer periphery of the inner cylinder pipe 16α from which exhaust gas is not discharged. 16 can also pass through, and the silencer cylinder 16
This has the advantage that the silencing effect can be shared whether the exhaust gas is introduced from either the left or right side.

In each of the embodiments of the present invention, the end portion of the muffler can be formed and installed in any exhaust pipe, and the appearance of the muffler can be improved.

As explained above, according to the present invention, there are mufflers located on both sides of the rear wheels, a chamber located in front of the rear wheels and communicating with the mufflers, and left and right exhaust introduction pipes for introducing exhaust gas from the engine. In the exhaust muffling device for a motorcycle, an inner cylindrical pipe communicating with the left and right exhaust introduction pipes is disposed in the chamber, and an opening is provided on the outer periphery of the inner cylindrical pipe, and
A cylindrical sound damping material is provided with a gap radially outward from the opening, and is supported so that the exhaust gas is discharged into the chamber through the opening gaps on the outer periphery of both ends of the sound damping material. The high frequency components of the waves can be effectively damped and there is no need to attach sound absorbing material for vibration prevention to the inner surface of the chamber, so the structure of the chamber is simplified, the effective volume can be secured accordingly, and the exhaust wave W can be made compact. can do. Furthermore, since the muffling tube can be molded separately from the chamber, plating of the chamber is facilitated, and the appearance and durability of the chamber are improved.

[Brief explanation of drawings]

FIG. 1 is a left side view showing the entire motorcycle equipped with the exhaust system of the present invention, and FIGS. 2 and 6 are, respectively,
A plan sectional view and a cross sectional view showing a first embodiment of the present invention,
FIG. 4 is a longitudinal sectional view taken along the line A-A in FIG. 6, and FIG. 5 is a plan sectional view showing a second embodiment of the present invention. 1... Engine, 2... Exhaust L3... Muffler, 4
. . . Rear wheel, 11 . cylindrical part,
16α'...opening, 16b...middle cylinder part, 16b'.
... Sound absorption hole, 16C ... Outer cylinder part, 19 ... Passage groove,
19α...Opening, 20...Sound absorbing material, 21°21'
...Chamber expansion chamber, 62...Muffler expansion chamber.

Claims (1)

[Claims] 1. In an exhaust silencer for a motorcycle, which includes a muffler located on both sides of the rear wheel, a chamber located in front of the rear wheel and communicating with the muffler, and left and right exhaust introduction pipes for introducing exhaust gas from the engine. , an inner cylindrical pipe communicating with the left and right exhaust gas introduction pipes is all disposed within the chamber, an opening is provided on the outer periphery of the inner cylindrical pipe, and a cylindrical sound deadening material is provided with a gap radially outside the opening. 1. An exhaust muffling device for a motorcycle, characterized in that the exhaust gas is discharged into the chamber from opening gaps on the outer periphery of both ends of the muffling material.