JPH01125514A - Manufacture of muffler - Google Patents

Abstract

PURPOSE:To enable high-density filling of a glass wool layer by winding a glass wool layer, in which a solution has been impregnated, on the outer circumference of a muffler pipe having a perforated part, and by drying the glass wool layer after an outer pipe has been fitted on the outside thereof under an undried condition. CONSTITUTION:In manufacturing a muffler, first, a stainless wool layer 7 and a glass wool layer 8 are successively wound around the outer circumference of the perforated part of a muffler pipe 5 in which a large number of sound- passing holes 6 are formed around all the circumference. The glass wool layer 8 is previously formed in a cloth shape, and after a solution containing an inorganic binder such as silica or alumina has been brushed thereon or has been impregnated thereinto by immersion, it is wound around the outer circumference of the stainless wool layer 7 under an undried condition. Next, after an outer pipe has been fitted on the outer circumference of the glass wool layer 8, the glass wool layer 8 is dried. In this case, the expansion of the glass wool layer 8 is restrained by the existence of the outer pipe 9. Then, both ends of the outer pipe 9 are welded to the muffler pipe 5 to complete the manufacture.

Description

DETAILED DESCRIPTION OF THE INVENTION A.0 Objective of the Invention E.1. INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a method for manufacturing a muffler used for muffling sounds from internal combustion engines or other noise sources.

E2. Prior Art Conventionally, for example, as a muffler for an internal combustion engine, as shown in FIG. Insert the glass wool layer (3) that has been dried and put the outer tube (
4) is manufactured by inserting and fitting.

Problems to be Solved by the Present Invention In the conventional manufacturing method, since the glass wool rii (31) is already in a dry state before it is inserted into the sound deadening pipe (2), the layer is There are many voids, so if the glass wool layer (3) in this state is simply inserted around the outer circumference of the sound deadening pipe (2), the vibrations of the inner and outer pipes will induce large vibrations in the glass wool layer (3). There is a problem in that the fibers are likely to break and be easily sucked and scattered through the holes in the sound deadening pipe (2).

Further, there is a problem in that the glass wool layer (3) does not adhere well to the muffling pipe (2) and the outer tube (4), and gaps are generated between them, reducing the muffling effect. In addition, when inserting the outer tube (4) around the outer periphery of the glass wool layer (3), the dried glass wool is rubbed against the insertion side end surface of the outer tube (4) and breaks and scatters, creating a poor working environment. Become.

Furthermore, the adhesion between the outer circumferential surface of the glass wool layer (3) and the inner surface of the outer tube (4) is poor, and in particular, the third layer
If the joint bead part (bl) as shown in the figure is present, the glass wool layer (3) will not spread over both sides of the core part, creating a space and reducing sound deadening properties.
) is difficult to insert.

Therefore, an object of the present invention is to propose a method for manufacturing a silencer that solves the above-mentioned problems.

B6 Structure of the Invention B16 Means for Solving Problems In order to solve the above-mentioned problems, the present invention provides an aqueous solution containing an inorganic binder on the outer periphery of the perforated part of a sound deadening pipe having a perforated part. After winding the glass wool layer impregnated with, in the undried state of the glass wool layer,
An outer tube with a diameter slightly larger than the outer diameter of the layer is inserted into the outer periphery,
The glass wool layer is then dried.

The glass wool layer containing the aqueous solution becomes denser between the glass wool layers due to the surface tension of the aqueous solution, and has a higher density than before it becomes hydrated.After inserting the outer tube in this hydrated state, When the glass wool is dried and its moisture is removed by evaporation, a force acts within the glass wool layer to restore and expand it to its dry bulk, but this expansion is suppressed by the outer tube. Therefore, the dried glass wool layer is maintained at the above-mentioned high density.

Row 3. Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 4.

(5) is a sound deadening pipe, and a sound hole (6) is formed along the entire circumference in the middle of the pipe. (7) is a stainless wool layer, which is wound around the outer periphery of the perforated portion having the sound holes (6). (8) is a glass wool layer which is formed into a cloth shape in advance and coated with silica (SiOz) or alumina (Ajz).
After impregnating with an aqueous solution containing an inorganic binder such as g3) by brushing or dipping in the liquid, the stainless wool layer (7) is wound in an undried state around the outer periphery of the stainless wool layer (7).
As shown in FIG. 4, this winding operation is carried out by winding a cloth-like glass wool (8a) cut into a trapezoid around the outer periphery of the stainless wool layer (7) of the sound deadening pipe (5) from its wide side. As a result, the narrow side is wound around the upper layer of the glass wool layer (8), forming a tapered portion as shown in (8b) in FIG. In addition, the glass wool layer impregnated with this aqueous solution becomes denser between the glass wools due to the surface tension of the aqueous solution, and has a higher density and a smaller volume than before water impregnation. Next, an outer tube (
9) Insert. The inner diameter of this outer tube (9) and the outer diameter of the winding of the glass wool layer (8) are set so that a slight gap is created between them so that the outer tube (9) can be easily inserted.

After the outer tube (9) is inserted, the glass wool layer (8) is dried by evaporating the moisture contained therein by natural drying or forced drying. As a result of this drying, the glass wool layer (8) attempts to expand and restore its bulk to its dry state before being impregnated with the aqueous solution.
9), and expansion beyond the crimped state is suppressed.

Therefore, the glass wool layer (8)
) side and the outer tube (9), and its density is
It is maintained at a high density close to the density in the water-containing state. In addition, as shown in Fig. 3, there is a joining bead (') on the inner surface of the outer tube (9).
Even in the case of having b), due to the expansion of the glass wool layer (8), the glass wool is interposed around the joint bead portion (mountain) without leaving any voids. In addition, after fitting the outer tube (9), its both ends (9a) (9b) are connected to sound deadening pipes (
5) Weld and fix.

The above-mentioned glass wool layer may be a needle mat made by inserting needles into glass wool so that the fibers are intertwined with each other, or a felt-like material.

Effects of the Invention As described above, according to the present invention, when the outer tube is inserted, the glass wool layer is impregnated with an aqueous solution and its bulk is reduced. Therefore, there is very little scattering of glass wool, and the work environment is good.
In addition, the moisture in the glass wool layer is evaporated during the subsequent drying process, but the density of the glass wool layer is
It is maintained in a state close to the high density when it is in a water-containing state, and it is possible to improve the silencing efficiency. In addition, since the glass wool layer has a high density, this glass wool is less likely to scatter from the sound hole of the sound deadening pipe. Furthermore, when drying, the glass wool layer expands, so that the inner and outer surfaces of the glass wool layer come into close contact with the sound-absorbing pipe side and the outer pipe, and as in the prior art, voids are created between the inner and outer surfaces of the glass wool layer, reducing the sound-dampening effect. In addition, even if there is a joint bead on the inner surface of the outer tube, the glass wool can be spread around the joint bead to prevent the sound deadening effect from deteriorating.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an embodiment of the present invention in a separated state, Fig. 2 is a side sectional view showing an assembled state, Fig. 3 is an enlarged sectional view taken along line A-A in Fig. 2, and Fig. 4. 5 is a plan view showing the glass wool winding operation, and FIG. 5 is an isolated side sectional view showing the conventional method. (5)...Sound-muffling pipe (6)...Sound hole (8)...Glass wool layer (9)...Outer pipe

Claims (1)

[Claims] After winding a glass wool layer impregnated with an aqueous solution containing an inorganic binder around the outer periphery of the perforated part of a sound deadening pipe having a perforated part, in the undried state of the glass wool layer, the layer is wrapped around the outer periphery of the perforated part. A method for producing a silencer, comprising: inserting an outer tube having a slightly larger diameter than the outer diameter of the silencer, and then drying the glass wool layer.