JPS5847206Y2 - SHOYOONKI - Google Patents

Description

[Detailed description of the invention] This invention relates to a silencer used for muffling the exhaust of internal combustion engines such as automobiles, and has a simple structure and low internal flow resistance.
Furthermore, the present invention aims to provide a muffler that can effectively muffle noise ranging from low frequencies to high eVc.

Conventionally, as the above-mentioned muffler, an expansion, interference, or resonance muffler, or a sound absorbing muffler using glass wool or the like has been generally used.

However, although these conventional mufflers are effective in muffling high-frequency components of noise, they are not sufficient in muffling low-frequency components. If this were to be done, the overall volume of the muffler would have to be increased and the internal structure would have to be made more complex, which would not only make the device unnecessarily large but also result in increased exhaust flow path resistance.

The silencer of the present invention has been devised to eliminate the above-mentioned inconveniences, and the present invention will be explained below with reference to drawings showing embodiments.

As shown in FIG. 1, the muffler case 1 has an upper case piece 2 and a lower case piece 3 that are joined together in the middle, and one or more communication holes 5 are bored inside the case 1. As shown in FIG.
It is divided into

A heat-resistant and sound-absorbing material 8 such as alumina grains, foamed metal, or foamed stone is integrally molded and attached to the upper and lower surfaces of the partition plate 4 so as to cover the communication hole 5 .

Here, the sound absorbing material 8 that flows into the communication hole 5 connects the upper and lower parts of the partition plate 4 and is formed integrally, so the sound absorbing material 8 is firmly held on the partition plate 4 and does not peel off. I'm not afraid to try it.

A chamber divided into upper and lower parts in the silencer case 1 6. An exhaust inlet pipe 9 and an exhaust outlet pipe 10 are connected to γ, respectively.

The operation of the silencer of the present invention constructed as described above will be explained below.

Exhaust gas entering the case 1 through the inflow pipe 9 first enters the upper chamber 6 and expands, where the pulsating pressure is alleviated and the exhaust gas is subjected to a first-stage noise damping effect.

This exhaust gas then enters the heat-resistant sound-absorbing material 8 from the top surface downward.

The sound absorbing material 8 is irregularly formed with a large number of small holes that communicate with each other, and while the exhaust gas passes through this sound absorbing material, small expansions and contractions are repeated to attenuate the pulsating pressure. The pulsating pressure and the sound pressure of the noise contained in the exhaust are attenuated by the friction of (
the second stage noise damping action) flows out into the chamber 1 below.

The noise contained in the exhaust cannot be removed unless it passes through a porous sound absorbing material.

As the exhaust gas enters the upper chamber 6 in a disturbed state, while passing through the sound absorbing material 8, the noise consisting of pulsating pressure and sound pressure is attenuated, and the exhaust gas itself is also subjected to a rectification effect, reducing the road area. Due to the spread of the flow, the flow velocity also decreases, and when it enters the lower chamber 7, it does not generate Karman vortices and generate secondary noise.

The exhaust gas that has flowed into the chamber 7 is in a rectified state with no sound, so it can be discharged as it is, but the pulsating pressure that remains will be further increased due to expansion when the exhaust gas flows out from the sound absorbing material into the chamber 7. is damped (third stage damping action), and the outflow pipe 10 from the chamber 7
When it flows out, it is subjected to the fourth-stage noise-damping effect of contraction, and is discharged with its pulsating pressure and sound pressure significantly attenuated.

Porous heat-resistant sound-absorbing materials have already been widely used as sound-absorbing elements in automobile silencers, but while conventional sound-absorbing materials were formed into a cylindrical shape, the sound-absorbing material of the present invention The device uses sound-absorbing material in a flat shape, and has the following practical effects.

(1) While the exhaust gas passes through the upper and lower chambers 6 and 7 and the sound absorbing material 8, the pulsating pressure of the exhaust gas and the sound pressure of the noise contained in the exhaust gas are attenuated by large and small expansions, contractions, and friction between the sound absorbing materials. Therefore, exhaust noise can be effectively muffled from low frequencies to high frequencies.

(2) Upper case piece 2 that can be easily molded by press working,
The lower case piece 3 and the diaphragm combined with the sound absorbing material are connected to the inflow pipe 9.
, the outflow pipes 10 can be sandwiched and overlapped, and the muffler can be manufactured easily by combining them by ordinary means such as welding or bolting.

(3) It is easier to form the sound absorbing material into a flat shape by sandwiching the partition plate 4 than with the conventional cylindrical mold.

(4) By widening the exhaust inflow area of the sound absorbing material, it is easy to reduce the resistance to exhaust.

(5) A thin and compact silencer can be obtained.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being an exploded perspective view and FIG. 2 being a longitudinal side view. 1... Silencer case, 2... Upper case piece, 3... Lower case piece, 4... Partition plate,
5...Communication hole, 6゜1...Chamber, 8...
...Heat-resistant sound-absorbing material, 9...Inflow pipe, 10...
...Outflow pipe.

Claims (1)

[Scope of utility model registration request] The upper case piece 2 and the lower case piece 3 are joined together with a partition plate 4 in between to form a muffler case 1. A communication hole 5 of a suitable size is bored, and a porous heat-resistant sound-absorbing material 8 is integrally molded and fixed to the upper and lower surfaces through the communication hole to constitute a sound-deadening element, and the upper and lower surfaces of the sound-deadening element and the sound-deadening element are formed. A muffler characterized in that chambers 6 and 1 serving as expansion chambers are formed between an inflow pipe 9 and an outflow pipe 10, respectively, between the muffler case 1 and the muffler case 1.