JPH0454207A - Muffler - Google Patents

Abstract

PURPOSE:To decrease the pressure of exhaust gas so as to enhance the damping effect of exhaust sound, particularly of exhaust sound in a high frequency range by providing a deflector upon which exhaust gas flowing from small holes, in a tail projected externally from the inside of the body of a muffler, at a position which is distant from the inner end of the muffler by a length smaller than a predetermined length. CONSTITUTION:A closed box-like muffler body 2 of a muffler 1 has one side part which is inserted therein with an inlet pipe 3 connected to an exhaust pipe 3 from an engine, and the other side part which is lower than the one side part and is fixed thereto with a tail 5 that is projected into the outside from the inside of muffler body 2. Several holes 4 are formed in the part of the inlet pipe 3 which is inserted into the muffler body 2, so that exhaust gas can flow out from the inlet pipe 3. Further, partition walls 8, 8 are provided between the inlet pipe 3 and expansion chambers 6, 7 in the vicinity of the tail 5. In this arrangement, a deflector 10 having a plurality of small holes 11 is formed on the exhaust gas stream inlet side of the tail 5. The deflector 10 has been drawn into a star-like shade so that the area thereof is increased. Accordigly, exhaust gas impinges upon the deflector 10, thereby it is possible to lower the sound level of noise in a high frequency range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a muffler that is attached to the exhaust pipe of a general-purpose engine to reduce exhaust noise.

[Conventional technology]

Regarding this type of silencer, for example, Utility Publication No. 619141
There is a prior art in the publication No. Here, in a muffler in which a flat-shaped outlet pipe is fixed to the muffler body, a baffle-shaped baffle plate is provided at the inflow part of the outlet pipe, and the exhaust gas is rectified by the baffle plate and discharged. It has been shown to reduce airflow noise in the outlet tube section.

[Problem to be solved by the invention]

By the way, in the prior art described above, a current plate is provided at the inflow portion of the flat outlet pipe to obtain a noise reduction effect.

Incidentally, it is required to attach a deflector that can freely change the exhaust direction to the outflow portion of the outlet pipe, and for this reason, there is a tendency for the outlet shape to shift from a flat shape to a round shape. When the shape is round like this, it is difficult to attach a rectifying plate to the inflow portion.

Generally, in a muffler with a tail that protrudes from the inside to the outside, if the tail is flat, the exhaust gas will not flow in even if there are only a number of holes at the inlet. Collision with the wall on the side you hit and the wall on the opposite side. It is known that this collision can reduce the exhaust gas pressure and effectively muffle the sound. Therefore, even in the case of a round tail, the noise reduction effect can be improved by making the shape near the inlet so that the exhaust gas collides with it.

The present invention has been made in view of these points, and its purpose is to effectively attenuate and reduce exhaust noise by changing the shape of the vicinity of the inlet of the tail through which exhaust gas finally passes. The objective is to provide a possible silencer.

[Means to solve the problem]

In order to achieve the above object, the muffler of the present invention has a round tail protruding from the inside of the muffler main body to the outside, and exhaust gas flows into the muffler for a predetermined length from the inner end of the muffler body of the tail. In the muffler formed with a plurality of small holes, a collision wall is provided between the tail and an inner end of the muffler for a predetermined length, with which exhaust gas flowing from the small holes collides. .

[For production]

Based on the above configuration, the exhaust gas that has flowed into the muffler main body is expanded and depressurized within the muffler main body, thereby being muffled.
Furthermore, the exhaust gas finally flows through the small hole in the tail and collides with the collision wall, reducing the exhaust gas pressure and attenuating the exhaust sound.

In particular, exhaust noise in a high frequency range is effectively reduced.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In FIGS. 1(a), (b), (c), and (d), the first embodiment of the present invention will be described. Reference numeral 1 indicates a muffler, and a closed box-shaped muffler main body 2 is shown. have

An inlet pipe 3 connected to an exhaust pipe from a general-purpose engine (not shown) is inserted into one side of the muffler main body 2 and is fixed by welding, and a tail 5 is fixed to the lower part of the main body 2 so as to protrude from the inside to the outside. ing. A large number of holes 4 are arranged in the axial direction at the insertion portion of the muffler main body 2 of the inlet pipe 3, allowing exhaust gas to flow out. The muffler main body 2 has an inlet pipe 3. The vicinity of the tail 5 is an expansion chamber 6.7, and partition walls 8, 8 are provided between these expansion chambers 6.7, and the partition wall 8 is cut out and bent to form a through hole 8a and a passage 9. There is.

The tail 5 has a round shape, and a deflector (not shown) or the like can be attached to the outlet side of the tail 5. The inner end side of the silencer main body 2 of the tail 5 is a plate 5a.
On the exhaust gas inlet side of the tail 5, a collision wall 10 having a plurality of small holes 11 has a predetermined length! Bamboo collision wall IO
The collision chamber 10a is formed by converging into a star shape so that the area of the collision chamber 10a increases.

As is clear from FIG. 1(b), the collision wall 1 (1) is placed on the side facing the small holes 11 so that the exhaust gas flowing into the tail 5 from the plurality of small holes 11 collides with the collision wall 10. It is formed.

With this configuration, exhaust gas from the engine flows into the expansion chamber 6 in the muffler main body 2 through the hole 4 of the inlet pipe 3, thereby being expanded and depressurized, and then passes through the through hole 8a.

As it passes through the passage 9, it collides and is depressurized, and then flows into the expansion chamber 7 where it is expanded and depressurized. In this way, due to the expansion and pressure reduction of the exhaust gas, the exhaust noise is gradually eliminated. Then, the exhaust gas flows into the collision chamber tOa through the small hole 11 of the collision wall ■0 formed in the tail 5, and collides with the inside of the collision wall IO, thereby reducing the exhaust pressure and attenuating the exhaust sound. The exhaust gas is discharged from the tail 5 to the outside.

As a result, the characteristics of the exhaust sound become as shown in FIG. 2. That is, compared to the conventional round tail shown by the broken line, the noise level in the high frequency range is reduced due to the collision of the exhaust gas at the collision wall 10 as shown by the solid line. Further, a sufficient collision area of the collision wall 10 is obtained, and the pressure of the exhaust gas is reduced by collision regardless of the directionality of the exhaust gas flowing in from the small hole 11.

Referring to FIG. 3, a second embodiment of the present invention will be described.

In the case of FIGS. 3(a) and 3(d), the peripheral wall of the tail 5 is intermittently cut out to form small holes 11, the cutout piece 12 is bent inward, and the inner side of the cutout piece 12 serves as a collision wall. .

As a result, the exhaust gas flowing in from the small hole 11 is guided by the cutout piece 12 and directed toward the adjacent cutout piece 12,
It collides with the adjacent notch piece 12, and the exhaust gas pressure is reduced.

In the case of FIGS. 3(b) and 3(e), a small hole 11 is provided in the peripheral wall of the tail 5, and a cross-shaped collision plate I is provided as a collision wall inside.
3 is inserted, and the collision chamber 10a is divided into four sections.

In the case of FIGS. 3(c) and 3(f'), a small hole 11 is provided in the peripheral wall of the tail 5, and a lattice-shaped collision plate 13 is inserted inside to form a collision chamber 10a divided into eight parts. .

In the case of FIGS. 3(b) and 3(c), the distance between the small hole 11 and the collision plate 13 is shortened, and the exhaust gas collides with the collision plate 13, thereby reducing the exhaust gas pressure and producing a silencing effect. obtain.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto.

〔Effect of the invention〕

As described above, according to the present invention, a collision wall is provided in the tail for a predetermined length from the inner end of the muffler, with which the exhaust gas flowing in from the small hole collides. Since the exhausted exhaust gas collides with the collision wall, the pressure of the exhaust gas is reduced, and the effect of damping exhaust noise is improved, particularly in the high frequency range.

Furthermore, the collision wall is formed into a star shape on the inlet side of the tail,
Alternatively, a part of the tail is cut out and bent to the inside of the tail, or a collision plate is inserted inside the tail, so that a wide collision area is obtained and the exhaust gas reaches the collision wall or collision plate. Since the distance is shortened, a reduction in the exhaust gas pressure is obtained due to the collision of the exhaust gases.

[Brief explanation of drawings]

FIG. 1(a) is a sectional view showing the first embodiment of the silencer of the present invention, FIG. 1(b) is a sectional view taken along the line bb in FIG. 1(a), and FIG. Fig. 1(b) cc sectional view, Fig. 1(d)
) is a perspective view of the entire tail, FIG. 2 is a characteristic diagram of exhaust noise, FIGS. 3(a), (b), and (c) are front views of main parts showing the second embodiment of the present invention, and FIG. Figure 3 (d), (e)
, ('') are respectively shown in Figure 3 (a), (b),
It is a perspective view of the whole tail corresponding to (c). ■... Silencer, 2 holes, 5... Tail, IO... Collision wall, 10a piece, 13... Collision plate... Silencer body, 3... Inlet pipe, 46.7. ... Expansion chamber, 8 ... Partition wall, ... Collision chamber, 11 ... Small hole, 12 ... Notch ya momme

Claims (2)

[Claims] (1) A sound muffler having a round tail protruding from the inside of the muffler body to the outside, and forming a plurality of small holes into which exhaust gas flows over a predetermined length of the tail from the inner end of the muffler. within a predetermined length of the tail from the inner end of the silencer,
A muffler characterized in that a collision wall is provided with which exhaust gas flowing from the small hole collides. (2) The collision wall is formed by forming the inlet side of the tail into a star shape, by cutting out a part of the tail and bending it inward, or by inserting a collision plate into the inside of the tail. The muffler according to claim 1, characterized in that: