JPS6141935Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improvement in a fluid passage having a structure that uses a sound-absorbing material to reduce the sound generated by fluid flowing inside.

There is a sound absorbing type muffler M using a sound absorbing material as a muffler installed in the exhaust system of an automobile. Conventionally, as shown in FIG. 1, such a muffler M has an inner pipe b installed inside an exhaust gas conduit a with a predetermined interval l so as to form a double pipe, and the exhaust gas is The gap between the conductive pipe a and the inner pipe b is filled with sound absorbing material c at a predetermined density. The inside of the tube b is a tube having a large number of small holes d in its peripheral wall, such as a perforated tube or a punched tube. Therefore, when the exhaust gas G flows through the exhaust gas conduit a, its sound waves are absorbed by the sound absorbing material c through the small holes d of the inner tube b, thereby reducing the sound.

Furthermore, in the exhaust system of a car, a sound absorbing structure part using a sound absorbing material C is sometimes provided in the exhaust pipe part, but in such cases, the structure is similar to that of the above-mentioned sound absorbing type muffler M. (For example, Utsukai 56-
(See Publication No. 173713).

However, when adopting the sound-absorbing structure as described above, first, the inner pipe b is installed in the exhaust gas conduit pipe a, which serves as a fluid passage, and then the sound-absorbing material c is filled, but these steps are not necessary. is very troublesome.
Particularly when the fluid passage is bent, it is difficult to fill the sound absorbing material c in a predetermined manner, resulting in a significant decrease in assembly work efficiency.

Therefore, this idea is a fluid that can be easily assembled by simply forming a pre-prepared sound-absorbing tube into a ring shape and inserting it into a predetermined position, and which can obtain the same sound-absorbing performance as the conventional structure. It provides a passageway.

An embodiment in which the fluid passage according to the invention is applied to a muffler in an automobile exhaust system will be described below with reference to FIG. 2.

As shown in FIG. 2, the muffler 1 of this embodiment has a large number of exhaust sound guiding holes 3 in the peripheral wall 2.
A plurality of ring-shaped sound absorbing tubes 5 are filled with sound absorbing material 4 at an appropriate density.
is installed on the inner circumferential surface 9 side of the exhaust gas conduit pipe 6.

The ring-shaped sound-absorbing tube (hereinafter simply referred to as tube) 5 is made of aluminum alloy or copper compound, and as shown in FIG. It is made up of things. The circumferential wall portion 2 of the tube 5 is formed thin, and both ends 7 and 8 are not fixed, and is provided with elasticity so that the ring diameter l' can be appropriately displaced. Ends 7, 8
is made smaller in diameter than the end 7 by drawing one of them, for example, the end 8 side. In this tube 5, a sound absorbing material 4 made of glass wool or the like is housed at a predetermined packing density. In addition, this tube 5
The length dimension, that is, the outer diameter dimension l' can be determined as appropriate according to the installation location, and at the same time, the inner diameter dimension of the exhaust gas conduit pipe 6 can be set so that it can be closely attached to the inner circumferential surface 9 side of the exhaust gas conduit pipe 6. The diameter is set slightly larger than l″.

As shown in FIGS. 2 and 3, a large number of exhaust sound guiding holes 3 are arranged on the entire surface of the peripheral wall 2, and the diameter of the holes is such that the sound absorbing material 4 inside the peripheral wall does not emit air. It is formed to a certain size. Emitted engine noise and the like are absorbed by the sound absorbing material 4 through the exhaust sound guiding holes 3 and are attenuated by sound absorption.

The exhaust gas conduit pipe 6 is formed into a cylindrical shape, as shown in FIG. Further, this exhaust gas conduit pipe 6 is attached to a baffle plate constituting an expansion chamber (not shown) of the muffler 1, so that a predetermined amount of exhaust gas G can be discharged.

Next, the operation of the silencer configured as described above will be explained.

When forming the sound-absorbing tube 5 into a ring shape, the sound-absorbing material 4 must first be filled into the tube 5. In this case, the tube 5 must be formed into a C-shape in advance as shown in FIG. I'll keep it. Then, the sound absorbing material 4 is stuffed into the tube 5 from either one of the ends 7, 8 (or both ends may be used) by an appropriate press-fitting means. Once the sound absorbing material 4 is evenly distributed inside the tube, the ends 7 and 8 are
Just face them and fit them together.

When installing the tube 5 filled with this sound absorbing material 4 inside the exhaust gas conduit 6,
As shown in FIG. 3, the tube 5 is press-fitted from the opening 10 at one end of the exhaust gas conduit 6 in the direction of the arrow. At this time, the outer diameter l' of the tube 5 is slightly larger than the inner diameter l'' of the exhaust gas conduit 6, but both ends 7 and 8 of the tube 5 are not fixedly connected. Since the tubes 5 are simply fitted together, the outer diameter l' of the tube 5 can be varied.Therefore, the tube 5 can be elastically locked in the exhaust gas conduit 6.
In this way, the required number of tubes 5 can be installed at predetermined locations on the exhaust gas conduit 6, and the silencing effect can be easily achieved.

Further, since the ring diameter of the tube 5 can be set to an appropriate size according to the installation location, it is possible to set the ring diameter to an appropriate size according to the installation location. As shown in FIG. 2, the installation work described above can be performed in the same way when installing the exhaust gas conduit 11 in which the pipe diameter is changed.

As described above, the fluid passage of this invention consists of a plurality of ring-shaped sound-absorbing tubes each having a structure in which the peripheral wall has a large number of small sound wave-guiding holes, and the inside is filled with a sound-absorbing material at an appropriate density. is installed on the inner circumference side of the flow path, so it can be easily assembled as a sound absorption structure by simply inserting a pre-prepared sound absorption tube into a coiled structure into the flow path. At the same time, it is possible to obtain the same sound absorption performance as the conventional structure.

This invention is not limited to application to the exhaust system of an automobile as in the above embodiment, but can be applied to various fluid passages that produce noise to obtain a desired noise reduction effect, and the structure has also been registered as a utility model. It goes without saying that various design changes can be made without departing from the technical idea set forth in the claims.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway sectional view showing the conventional mounting structure of the sound absorbing material filling part in a silencer, Fig. 2 is a partially cutaway sectional view showing an embodiment of this invention, and Fig. 3
The figure is a perspective view of the main part showing the state before installation of the tube,
FIG. 4 is a partially cutaway sectional view showing the same modification. DESCRIPTION OF SYMBOLS 1... Silencer, 2... Peripheral wall part, 3... Exhaust sound guidance small hole, 4... Sound absorbing material, 5... Ring-shaped sound absorption tube, 6, 11... Exhaust gas conduction pipe.

Claims (1)

[Scope of utility model registration request] A plurality of ring-shaped sound-absorbing tubes each having a structure in which the peripheral wall has a large number of small holes for guiding sound waves and the inside is filled with a sound-absorbing material at an appropriate density are placed on the inner circumferential side of the flow passage. A fluid passage characterized by being installed in an array.