JP2513707Y2 - Exhaust silencer - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust silencer mainly used for vehicles such as motorcycles.

[0002]

2. Description of the Related Art Conventionally, there is an exhaust sound deadening device for a motorcycle which uses glass wool as a sound absorbing material (see Japanese Utility Model Laid-Open No. 52-149943). An example of this type of exhaust silencer is shown in FIG.

In FIG. 3, an exhaust silencer 1 is provided in an exhaust pipe 10 connected to an engine (not shown). The inner pipe 7 of the muffler 1 is provided with a large number of small holes 2. Glass wool 5 is filled between the inner tube 7 and the outer tube 3 that covers the outer circumference of the inner tube 7, that is, the expansion chamber 4. In addition, 6 is a cross. In this type of muffler 1, the exhaust sound level is reduced by the expansion of the exhaust gas and the absorption by the glass wool 5.

[0004]

However, since the sound absorption by the glass wool 5 is determined by the amount of the glass wool 5, it is necessary to increase the outer diameter of the muffler 1 in order to reduce the exhaust noise. For example, when the muffler 1 is enlarged in a motorcycle, it is necessary to dispose the muffler 1 in the rear part of the vehicle body in order to avoid the interference between the muffler 1 and a vehicle body frame (not shown), and the center of gravity of the motorcycle is moved backward Moving. The present invention has been made in view of the above conventional problems, and an object thereof is to reduce exhaust noise without increasing the size of the exhaust silencer.

[0005]

In order to achieve the above-mentioned object, the present invention interposes a punching steel wool covering the outer circumference of an inner tube between an inner tube having a small hole and glass wool , and The punched steel wool is fibrous
Of iron-based metal bundles, the fiber extending directions are orthogonal to each other
3 layers, and connect them by needle punching,
It is one that is entwined with the sea bream .

[0006]

According to this invention, the sound wave of the exhaust gas is absorbed by the punching steel wool having the three-layer structure through the small hole of the inner tube, so that the exhaust sound is reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the inner tube 7 is a baffle pipe in which a punching plate has a cylindrical shape, and punching steel wool 8 is wound around the outer circumference thereof. That is, the punching steel wool 8 that covers the outer circumference of the inner tube 7 is interposed between the glass wool 5 and the inner tube 7.

FIG. 2A shows a cross sectional view of the muffler (exhaust silencer) 1. As shown in FIG. 2 (a), the muffler 1 has a cross section having an oval shape narrow in the width direction W of the motorcycle so that the vehicle width of the motorcycle does not become large. There is. The punching steel wool 8 is shown in FIG.
As shown in the enlarged view of Fig.
5 μ-55 μ). This punching steel wool 8 is a state in which a horizontal line 8a extending in the circumferential direction A of the inner pipe 7 is vertically sandwiched by a vertical line 8b extending in the axial direction B (see FIG. 1) of the inner pipe 7, that is, a fibrous shape . A bundle of iron-based metal
A state in which three layers are stacked so that the stretched directions of the fibers alternate at right angles.
Then , they are connected by a needle punch (not shown), and are entwined with each other to have an integral three-layer structure. This three-layer structure is wound around the outer circumference of the inner pipe 7 twice. This punched steel wool 8 has a weight of 700 g to 1000 g per 1 square meter (thickness of 3 mm to 5 mm) , that is, 1 cubic meter in terms of volume density.
To have a weight of 140 kg to 333 kg per tor
It is compressed every time. Other configurations are similar to those of the above-described conventional technique, and the same portions or corresponding portions are denoted by the same reference numerals and detailed description thereof will be omitted.

In the above structure, the exhaust gas G introduced from the exhaust pipe 10 of FIG. 1 to the muffler 1 has a three-layer structure punching in which sound waves pass through the small holes 2 and the energy of the sound absorption is large. Since it is absorbed by the steel wool 8, the exhaust sound level can be lowered even with the muffler 1 having the same size as the conventional one. For example, according to an experiment conducted by the present inventor, the level of static noise measured at a position 2 m from the rear exhaust gas angle of 45 ° decreased from 99 dB to 98 dB.

In addition, in the vicinity 1a near the entrance of the muffler 1,
The high-temperature high-pressure exhaust gas G first collides with the punching steel wool 8 having a high strength and has a three-layer structure, and then hits the glass wool 5 having a low strength, so that the glass wool 5 can be protected. Therefore, the glass wool 5 can be prevented from scattering and the durability of the glass wool 5 can be improved.

By the way, it is conceivable to fill the space between the inner pipe 7 and the outer pipe 3 with punching steel wool 8. However, in this case, the heat insulating property is lost and the outer pipe 3 becomes hot. Also, it becomes heavy in weight. On the other hand, in this invention, the glass wool 5 is provided on the outer periphery of the punching steel wool 8, and the glass wool 5 acts as a heat insulating material, so that the outer tube 3 does not become hot.

It is also conceivable to use carbon fiber instead of punching steel wool 8. But,
In the case of carbon fiber, since it is necessary to continuously wind the carbon fiber around the inner tube 7, the cost is significantly increased. On the other hand, in this invention, punching steel bundled in three layers is used.
Wool 8 can be wrapped, so the cost does not increase so much.

It is also conceivable to use aluminum or brass fibers instead of punching steel wool 8.
However, fibers such as brass are easily burned by the high temperature exhaust gas G. On the other hand, in this invention, since the punching steel wool 8 having high heat resistance is used, there is no possibility of melting due to heat.

By the way, the weight per square meter (thickness 3 mm to 5 mm) of punching steel wool 8 is 70.
About 0g to 1000g , that is, 1 cubic meter
The most preferable weight is 140 kg to 333 kg . The reason is less than 700 g / square meter ,
That is , if it is less than 140 kg / cubic meter, the amount of punching steel wool 8 is too small and the density is low .
Technical Te, sufficient silencing effect can not be obtained, whereas, 1000 g /
Larger than square meter, ie 333kg
This is because if it is larger than cubic meters, it is not preferable in terms of weight and noise reduction effect.

The present invention can be applied to mufflers for automobiles, three-wheeled vehicles and four-wheeled vehicles, in addition to the muffler 1 for motorcycles.

[0016]

As described above, according to the present invention, since the punching steel wool having a three-layer structure covering the outer circumference of the inner tube is inserted between the inner tube having the small hole and the glass wool, the sound absorbing The punching steel wool of three-layer structure, which has excellent properties, can reduce the level of exhaust noise, and there is no fear that the exhaust silencer becomes large. Also, 3
Since the punched steel wool having a layered structure has excellent heat resistance and mechanical properties, the punched steel wool having a three-layered structure protects the glass wool from the exhaust of high temperature and high pressure, and thus the durability of the glass wool is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a muffler of a motorcycle showing an embodiment of the present invention.

FIG. 2A is a transverse sectional view of the same, and FIG. 2B is an enlarged sectional view of punched steel wool.

FIG. 3 is a vertical sectional view showing a muffler of a conventional motorcycle.

[Explanation of symbols]

1 ... muffler, 2 ... small hole, 3 ... outer tube, 5 ... glass wool,
7 ... inner tube, 8 ... punching steel wool.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-36013 (JP, A) Actually opened 63-168205 (JP, U) Actually opened 58-1716 (JP, U)

Claims (1)

(57) [Scope of utility model registration request] 1. An exhaust silencer in which a large number of small holes are provided on a side surface of an inner tube and glass wool is filled between the inner tube and an outer tube covering an outer circumference of the inner tube, wherein Punching steel wool covering the outer circumference of the inner tube is inserted , and the punching steel wool
Is a bundle of fibrous ferrous metals, with alternating fiber growth directions.
3 layers so that they are orthogonal to
An exhaust muffler that is integrated and entangled with each other .