JPS5941282Y2 - Resonant silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resonance type muffler, and more particularly, to a structure of a resonant type muffler having an excellent silencing effect.

Various types of mufflers have been developed in the past to muffle the noise propagated in gas passages, but one type of muffler is a resonant muffler, which uses resonance between a small hole and the air layer behind it. It is designed to absorb sound energy through resonance absorption, and has a structure as shown in FIGS. 1 and 2, for example.

That is, an inner cylindrical body part 2 through which noise-propagating gas flows, and an outer can-shaped body part 3 surrounding a predetermined space on the outer periphery of the cylinder part 2 to form a resonance chamber 5. A muffler 1 is constructed in which a cylindrical body part 2 and a can-shaped body part 3 are arranged concentrically.

By erecting the cylindrical resonance pipe section 4 in the resonance chamber 5 from the outer peripheral surface of the cylindrical body section 2, the gas passage 6 inside the cylindrical body section 2 and the can-shaped body section are connected to each other. The gas passage 6 is communicated with the resonance chamber 5 formed in the gas passage 6, thereby attenuating the noise propagated within the gas passage 6 by a resonance absorption method.

By the way, it is known that the resonance frequency f in such a resonance type muffler is generally expressed by the following equation (1).

However, V: Resonance chamber capacity C: Sound velocity t: 1 part of resonance pump γ: Inner diameter (radius) of the vig part On the other hand, as a result of the present inventors' close examination of the silencing effect of such a resonance type muffler, It has been learned from experience that the greater the length t and inner diameter (radius) γ of the resonant pipe section, while keeping rΣt constant at a certain resonance frequency f in the above equation, the better the silencing effect becomes.

Therefore, in order to further improve the silencing effect of the conventional resonance type muffler 1, even if it is attempted to increase the length t and the inner diameter (radius) γ of the resonance pipe portion 4 based on the above knowledge, Since the wall-to-wall distance S between the outer peripheral surface of the cylindrical body part 2 and the inner peripheral surface of the can-shaped body part 3 is short, it is extremely difficult to further increase the length t of the resonance pipe part 4. It was not possible to improve the silencing effect.

Of course, if the muffler is made larger, it becomes possible to provide a resonant pipe section with a large value of γ and γ, which improves the muffling effect, but this will greatly increase the manufacturing cost of the muffler, and the muffler will also become larger. As a result, it cannot be used in narrow spaces, causing problems such as curling.

Therefore, there has been a demand for the development of a muffler that has the same size as conventional mufflers, is inexpensive to manufacture, and can improve the muffling effect.

The present invention has been developed against this background, and its purpose is to provide an easy-to-manufacture sound damping device that can improve the sound damping effect without changing the resonance chamber capacity. It is about providing the equipment.

In order to achieve such an object, the present invention comprises: an inner cylindrical part through which noise-propagating gas flows; an outer can-shaped part surrounding a predetermined space on the outer periphery of the cylindrical part; A resonant silencer having a resonant pipe section that stands upright on a body portion and communicates the inside of the cylindrical body portion with a resonance chamber formed in the can-shaped body portion, the cylindrical body portion and the can-shaped body portion. The central axis of the resonant pipe is eccentric, so that the resonant pipe portion can be extended into the resonant chamber.

Hereinafter, the present invention will be explained in more detail based on embodiments shown in the drawings.

FIGS. 3 and 4 are diagrams showing a resonant silencer according to an embodiment of the present invention.

In these figures, reference numeral 11 indicates a resonance type muffler, which includes an inner cylindrical body part 12 through which the gas that propagates noise flows, and a resonance chamber 15 surrounding a predetermined space on the outer periphery of the cylinder body part 12. In other words, it has a double-cylindrical structure in which the cylindrical body 12 is inserted through the can-shaped body 13, and the can-shaped body 13 forms a The central axis of the cylindrical body 12 is eccentrically arranged downward with respect to the cylindrical body 13 in the figure.

In this muffler 11, the cylindrical resonance pipe section 14 is erected in the resonance chamber 15 from the outer peripheral surface of the cylindrical body section 12. 13 and the cylindrical body part 12 are eccentrically arranged, so that the cylindrical body part 1
2 and the inner peripheral surface of the can-shaped body part 13 can be made longer, so that the length t of the resonance pipe part 14 can be increased.
It is also possible to extend it into the resonance chamber 15 for a long time,
At the same time, the inner diameter (radius) γ of the resonance pipe can also be increased.

In this way, the resonance pipe section 14 extended into the resonance chamber 15 allows the gas passage 16 inside the cylindrical body part 12 to communicate with the resonance chamber 15, so that the gas passage Noise propagated through the filter 16 is effectively attenuated by the resonance absorption method.

Incidentally, in order to confirm this effect, in the equation (1) for the resonance frequency f described above, the resonance frequency f is 125 Hz.
Using the silencer of the present invention and a conventional silencer under conditions set to maximize the silencing effect in the vicinity,
A noise silencing test was conducted.

The dimensions of each part are as follows.

Example of this invention Conventional example Resonance chamber capacity (V) 900CC900CC Resonance pipe section length t) 30 cabinets 20m Resonance pipe section inner diameter (r) 7rn! n5.5rrrm The degree of eccentricity in this experimental example is a=11m as shown in Figure 4.
m, b=11 m.

The results are shown in FIG.

Figure 5 shows the attenuation amount (dB) relative to the noise frequency (Hz).
), in which the broken line shows the results for the silencer according to the present invention, and the solid line shows the conventional example.

As is clear from this figure, at a frequency of 125 Hz, the muffler according to the present invention achieves an attenuation of 7 dB, while the conventional example only achieves an attenuation of 4 dB. It was confirmed that it has a remarkable effect on sound deadening.

Note that the present invention is by no means limited to the specific examples shown, and various improvements and changes can be made based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

As detailed above, the resonance type silencer according to the present invention achieves further improvement in the silencing effect without increasing the capacity of the resonance chamber, and has a simple structure and is extremely easy to manufacture. It has a number of excellent effects, and has great industrial significance.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional resonant silencer, FIG. 2 is a view taken in the direction of arrow A in FIG. 1, and FIG. 3 is a sectional view of a resonant silencer according to an embodiment of the present invention. , and Figure 4 is B in Figure 3.
5 is a graph showing the results of a muffler test for the silencer shown in FIG. 1 (conventional type) and the silencer shown in FIG. 3 (according to the present invention). i, ii: Resonant silencer, 2.12: Cylindrical body part, 3. 13: can-shaped body part, 14: resonance pipe part, , 15: resonance chamber, 16: gas passage.

Claims (1)

[Scope of utility model registration request] an inner cylindrical part through which noise-propagating gas flows; an outer can-shaped part surrounding a predetermined space on the outer periphery of the cylindrical part; and a resonant pipe portion that communicates a resonance chamber formed in the can-shaped body portion, the central axes of the cylindrical body portion and the can-shaped body portion are eccentrically arranged, and the resonance pipe portion is connected to the resonant pipe portion. A resonance type silencer characterized in that it can be extended for a long time inside a resonance chamber.