JPH02140411A - Muffler - Google Patents

Abstract

PURPOSE:To obtain muffler effect in a comparatively large area by composing a part or all of the peripheral wall of a muffler box of an elastic film. CONSTITUTION:In an exhaust system of an engine 1, a muffler is formed by arranging a muffler box 3 on an outer periphery on the way of an exhaust pipe 2 while providing a through-hole 4 communicating with an inner space of the muffler box 3 on an outer periphery of the exhaust pipe 2. End walls of longitudinal both sides of the cylindrically formed muffler box is composed of metal plates 3a, 3a while the peripheral wall thereof is composed of an elastic film 3b made from rubber, etc. Acoustic pressure oscillations can be absorbed by the elastic deformation of the elastic film 3b, thereby the exhaust noise is effectively eliminated together with the resonance muffler effect of the muffler box 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a muffler mainly applied to an intake system or an exhaust system of an engine.

(Prior Art) Conventionally, according to Japanese Unexamined Patent Publication No. 58-15708, intake or 1. I [A sound deadening box is installed on the outer periphery of the air conduit,
A muffler is known in which a communication hole is provided on the outer periphery of the conduit to communicate with the interior space of the muffler box, and in this muffler, the peripheral wall of the muffler box is generally constructed of a metal plate.

(Problems to be Solved by the Invention) In the above-mentioned conventional device, since the peripheral wall of the sound deadening box is made of a metal plate, the sound deadening effect can only be obtained through resonance sound deadening, and there is a problem in that sounds other than a specific frequency cannot be sufficiently muffled. be.

The present invention has been made in view of such problems, and
The purpose is to provide a muffler that can provide a muffling effect over a relatively wide area.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a sound deadening box is provided on the outer periphery of a conduit through which air intake or exhaust air passes, In a muffler provided with a communicating hole, a part or all of the peripheral wall of the muffler box is made of an elastic membrane.

(Function) Since part or all of the peripheral wall of the sound deadening box is made of an elastic membrane,
Sound pressure vibrations are absorbed by the elastic deformation of the elastic membrane, and together with the resonance silencing effect, effective silencing can be achieved over a relatively wide frequency range.

(Embodiment) The drawings show an embodiment in which the silencer of the present invention is applied to the exhaust system of an engine (1).

In the drawing, (2) indicates an exhaust pipe, and a sound deadening box (3) is provided on the outer periphery of the exhaust pipe (2), and the exhaust pipe (2) is
A communication hole (4) communicating with the internal space of the muffler box (3) was provided on the outer periphery of the muffler to constitute a muffler.

The muffling box (3) is formed into a cylindrical shape, and the end walls on both longitudinal sides of the muffling box (3) are covered with metal plates (
3a) The surrounding wall of the sound deadening box (3) was made of fluororubber or other elastic membrane (3b).

In this way, sound pressure vibrations can be absorbed by the elastic deformation of the elastic membrane (3b), and in combination with the resonance silencing effect of the silencing box (3), the exhaust noise of the engine (1) can be effectively silenced. I did it like that.

In this embodiment, the communication hole (4) is opened in the part of the exhaust pipe (2) where the sound pressure level is maximum so that sound pressure vibrations can be absorbed more effectively. ) A muffler (5) having a structure substantially similar to that of the prior art described above was provided on the downstream side of the muffler box (3).

Figure 3 shows the measurement results of the exhaust noise of the engine (1) conducted using the present example and a comparative example provided with only the muffler (5), where the a-line is the present example and the b-line is the comparison. This is an example, and as is clear from the figure, according to this embodiment, exhaust noise is reduced over a relatively wide rotational speed range (frequency range).

Although the fifth embodiment described above is applied to the exhaust system, it is of course possible to apply the invention to the intake system.

(Effects of the Invention) As described above, according to the present invention, part or all of the peripheral wall of the sound deadening box is made of an elastic membrane, and sound pressure vibrations can be effectively absorbed by the elastic deformation of the elastic membrane. The muffling effect can be obtained over a wide frequency range, and the structure of the muffler is simple because only a part or all of the peripheral wall of the muffler box is made of an elastic membrane.

[Brief explanation of the drawing]

Figure 1 shows one example of an engine exhaust system to which the present invention muffler is applied.
A diagram showing an example, FIG. 2 is a sectional view taken along the line ■-■, and FIG. 3 is a graph showing the silencing characteristics. (2)... Exhaust pipe (conduit) (3)... Sound deadening box (3b
)...Elastic membrane (4)...Communication hole 1st
Figure patent application by 3 people other than Honda Motor Co., Ltd. Figure 3

Claims (1)

[Claims] A part of the peripheral wall of the muffling box in a silencer comprising a muffling box provided on the outer periphery of a conduit through which air intake or exhaust air passes, and a communication hole communicating with the internal space of the muffling box provided on the outer periphery of the pipe. Or a silencer characterized by being entirely composed of an elastic membrane.