JP3020911B2 - Exhaust muffler structure for motorcycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an exhaust muffler for a motorcycle.

[0002]

2. Description of the Related Art Conventionally, as an exhaust muffler for a motorcycle, a tail pipe from which exhaust gas is discharged and a downstream end of the tail pipe are coaxially provided at a tail end portion of a housing through a hollow support bracket. There is a known one that supports a tail cover pipe that covers the front cover (for example, see Japanese Patent Application Laid-Open No. 7-208146).

[0003]

However, in such an exhaust muffler, since the support bracket has a hollow shape, the space functions as a resonance box due to the flow of the exhaust gas, and noise is generated. In particular, the total displacement is 90
It is likely to occur when using a single muffler with an engine of 0 cc or more.

Therefore, a hole is made in the support bracket,
Although the resonance effect is reduced by, for example, projecting the tail pipe from the tail cover pipe, the appearance may be impaired.

[0005] The present invention has been made in view of such a point, and without impairing the appearance at the tail end portion.
An object of the present invention is to provide a structure of an exhaust muffler for a motorcycle that can improve a noise reduction effect.

[0006]

According to a first aspect of the present invention, there is provided a tail pipe through which exhaust gas is exhausted via a hollow support bracket and a tail cover pipe covering a downstream end of the tail pipe. In the structure of the exhaust muffler for a motorcycle in which the support bracket is supported,
Allows the tail pipe to be supported by the housing.
An outer member and a space downstream of the outer member on the exhaust side.
Installed to support the tail cover pipe in the housing
And a heat-resistant first sound-absorbing material is disposed in the space of the support bracket.

According to the first aspect of the present invention, since the sound absorbing material is provided in the space of the support bracket, a synergistic effect of reducing the volume of the space and the sound absorbing effect of the first sound absorbing material. Thus, the space portion is prevented from functioning as a resonance box as in the related art, and the noise reduction effect is not impaired.
Therefore, in the tail end portion, the resonance effect is reduced without impairing the appearance, and the noise reduction performance is secured.

According to a second aspect of the present invention, in the structure of the exhaust muffler for a motorcycle according to the first aspect, the support bracket has a substantially conical shape projecting outward toward the center.

According to the second aspect of the present invention, the support bracket has a substantially conical shape that protrudes outward toward the center, and the support effect is enhanced by the shape, and vibration due to sound is reduced.

[0010] The invention according to claim 3, Te claim 1 or 2 structures smell exhaust muffler of a motorcycle according, made et al,
A second heat absorbing material having heat resistance is provided upstream of the inner member.

According to the third aspect of the present invention, by providing the second sound absorbing material in addition to the first sound absorbing material, the sound absorbing effect by the sound absorbing material is further enhanced.

[0012]

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.
FIG. 4 is an enlarged view of a tail end portion of the exhaust muffler.

As shown in FIG. 1, an exhaust muffler 1 for a motorcycle is provided by only providing one exhaust muffler for one engine.
This muffler is used for a four-cylinder engine (for example, 900 cc) having a high exhaust pressure.
a,... are formed, and an outer cylinder disposed coaxially outside the inner cylinder member 2 via a heat-absorbing sound-absorbing material 3 (eg, glass wool, stainless steel wool). A housing 9 comprising the member 4;
On one side, an inlet member 6 having a mounting bolt 5 is provided, and on the other side, an outlet member 7 is provided. The mounting bolt 5 connects the exhaust muffler 1 to a downstream end of an exhaust manifold (not shown). Further, a sealing member 8 for preventing leakage of exhaust gas is provided downstream of the inlet member 6.

A baffle plate 11 and first and second partition wall members 12 and 13 are provided in the inner cylindrical member 2 in this order from the exhaust upstream side. 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.
However, a third chamber 16 is formed between the first partition wall member 12 and the second partition wall member 13 so as to be partitioned. Therefore, the baffle plate 11 is provided in the first chamber 14.

Here, the baffle plate 11 is
Since the sound absorbing material 3 provided around the inner cylinder member 2 absorbs higher sounds more easily than low sounds, the exhaust gas passes through the baffle plate 11. Is changed to a high tone.

The baffle plate 11 has a disk portion 11A in which a large number of through holes 11a,... Are formed, and extends from the periphery of the disk portion 11A toward the inlet member 6 in the axial direction. And a peripheral wall portion 11B attached to the peripheral surface.

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 and 12c (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.

The first pipe member 21 penetrates not only the first partition wall member 12 but also the second partition wall member 13 through the third chamber 16, and the first chamber 14 and the second chamber 15 are communicated with each other, and the exhaust gas is guided from the first chamber 14 to the second chamber 15.

Similarly to the baffle plate 11 and the first partition wall member 12, the second partition wall member 13
A, and a peripheral wall portion 13B, and as shown in FIG.
A pair of second pipe members 22 are provided for communicating the chamber 15 with the third chamber 16. Second pipe member 22
Is smaller in diameter than the first pipe member 21. A large number of through-holes 23a,.
Are provided with the axis inclined. More specifically, the tail pipe 23 is provided with an outer pipe 25 that is shorter than the tail pipe 23 via a sound absorbing material 24 outside the tail pipe 23. The upstream part 23 is attached to the outer peripheral side of the inner cylinder member 2 and the downstream part is inclined so as to be located at the center side of the inner cylinder member 2.

The tail pipe 23 includes an outer pipe 25
The downstream portion protrudes more than the upstream portion, and the downstream portion is attached to the outlet member 7. A pipe 37 is fitted on the downstream end of the tail pipe 23.

The left and right sides of the tail pipe 23 are
A pair of second through holes 13a and 13b are provided for communicating the chamber 15 and the third chamber 16 with each other. Here, the second through-holes 13a, 13b are formed by the first through-holes 12b, 12c.
Can be adjusted in the vertical direction to adjust the muffling effect, but the through holes 12b, 12c and 13a,
It is considered that the effect of achieving the silencing effect is higher when the positions of 13b coincide in the vertical direction.

As shown in detail in FIG. 4, the discharge port member 7 includes a tail cover pipe 31 covering a downstream portion of the tail pipe 23, and the tail cover pipe 31 and the tail pipe 23 together with the outer cylinder member 4 and the inner pipe. And a support bracket 41 having a hollow shape attached to the tubular member 2. The support bracket 41 has one end connected to the tail pipe 23 upstream of the tail cover pipe 31 and the other end connected to the inner cylindrical member 2.
And a substantially conical inner member 32 coupled to the outer cylinder member 4
A substantially conical outer member 33 having one end joined to the tail cover pipe 31 and the other end joined to the inner member 32, and is formed between the inner member 32 and the outer member 33. The first sound absorbing material 34 having heat resistance (for example, glass wool, stainless wool) is provided in the space 41a. A second sound absorbing material 35 having heat resistance is attached to the upstream side surface of the inner member 32 by an attaching member 36. Here, the reason why the support bracket 41 including the inner member 32 and the outer member 33 is formed in a substantially conical shape is that, by doing so, vibration due to exhaust noise is reduced, and the support effect on the tail pipe 23 and the tail cover pipe 31 is obtained. It is because it is possible to reinforce.

According to the above configuration, the space 41a between the inner member 32 and the outer member 33 is filled with the sound absorbing material 34. Therefore, the volume of the space 41a can be reduced and the sound absorbing material 34 can reduce noise. By the synergistic effect with the effect, the space part which occurred conventionally does not function as a resonance box,
Even when used in an engine with a large total displacement, the noise reduction effect is not impaired.

Therefore, in order to avoid resonance, it is not necessary to make a hole in the support bracket 41 or make the tail pipe 23 project from the tail cover pipe 31, so that the appearance is not impaired at the tail end portion.
Noise due to the resonance effect can be reduced, and noise reduction performance can be ensured.

Since the support bracket 41 (the inner member 32 and the outer member 33) has a substantially conical shape projecting toward the exhaust downstream from the center, the support strength of the tail pipe 23 and the tail cover pipe 31 can be increased. In addition to the above, vibration due to exhaust noise can be reduced, and the noise reduction effect can be further enhanced.

[0027]

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 sound absorbing material is provided in the space of the support bracket for supporting the tail pipe, a synergistic effect of reducing the volume of the space and the sound absorbing effect of the sound absorbing material. Thereby, it is possible to prevent the space part which has been conventionally generated from functioning as a resonance box. Therefore, even when used as a single muffler of an engine having a large displacement, the noise reduction effect is not impaired.

According to the second aspect of the present invention, since the support bracket has a substantially conical shape projecting toward the exhaust downstream side toward the center,
The support of the tail pipe and the like can be reinforced by the shape, and the vibration due to the exhaust noise can be reduced.

According to a third aspect of the present invention, in addition to the first sound absorbing material,
Since the second sound absorbing material is provided, the sound absorbing effect by the sound absorbing material can be further enhanced.

[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.

FIG. 4 is an enlarged view of a tail end portion of the exhaust muffler.

[Explanation of symbols]

 Reference Signs List 1 exhaust muffler 9 housing 23 tail pipe 31 tail cover pipe 32 outer member 33 inner member 34 first sound absorbing material 35 second sound absorbing material 41 support bracket 41a space

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01N 1/10 F01N 7/08

Claims (3)

(57) [Claims] 1. A motorcycle exhaust muffler in which a tail pipe through which exhaust gas is exhausted and a tail cover pipe that covers a downstream end of the tail pipe are supported by a housing via a hollow support bracket. In the structure, the support bracket connects the tail pipe to the housing.
Outer member to be supported by the ring, and an exhaust downstream side of the outer member
The tail cover pipe is installed with space in the
An inner member supported by the housing, and a first heat-resistant first member in a space of the support bracket.
An exhaust muffler structure for a motorcycle, wherein the sound absorbing material is disposed. 2. The exhaust muffler structure for a motorcycle according to claim 1, wherein said support bracket has a substantially conical shape projecting toward the exhaust downstream side toward the center. To 3. A is found, the structure of an exhaust muffler of a motorcycle of the second claim 1 or 2 wherein sound absorbing material is So設which upstream has a heat resistance of the inner member.