JPH0399771A - Manufacture of al alloy-made silencer - Google Patents

Abstract

PURPOSE:To easily manufacture an Al alloy-made silencer having complicate structure by integrally brazing constituting parts in a hollow part made of the Al alloy arranged on the way of exhaust piping and an element in the inner part thereof. CONSTITUTION:The brazing is executed under non-oxidizing atmosphere, in which flux vapor of potassium fluoroaluminate complex of KAlF4, etc., fluoride of KBF4, etc., exists, without applying the flux on the whole face on member to be joined. That is, the brazing is executed by using vapor phase brazing method. By this brazing method, stuck quantity of the flux on this product surface is little and the Al alloy-made silencer having clean surface can be easily manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a muffler made of AA alloy, which is lightweight and inexpensive to manufacture.

[Conventional technology]

Gases emitted intermittently, such as exhaust gas from an engine, generate extremely loud noises when emitted directly into the atmosphere. Therefore, a silencer, also known as a muffler or silencer, is installed in the middle of the exhaust pipe to muffle the sound before releasing the exhaust gas into the atmosphere.

Silencers are devices that consume the acoustic energy of exhaust gas with as low a resistance as possible, and are basically divided into two types: cavity type and resonance type, as shown below. The basic formula is one that includes the above, but in many cases it is a complex formula that is a complex combination of the above.

First, as shown in Figure 1, a simple cavity silencer has a cavity (5) in the middle of the exhaust pipe line (4), and the attenuation amount db in this case is expressed by the following formula. be done.

db=IO・lOgto (j, -1-1/4 (m-
1/m) 2sin 2k ・(1 here m=52/S
t (area expansion ratio of conduit) k = 2πf/c, f = frequency,
C - speed of sound, l, cavity length.

Furthermore, an element (cavity type muffler e) is installed inside the device, as shown in Figure 2 (a) to e).
5) uses various elements 1-(2), and in reality, several elements are placed in one cavity.

Next, the resonant cavity type muffler is connected to the pipe (4) as shown in Figure 3.
A resonator (6) with a volume of ■ is provided outside the resonator (6).
This is a Lumholtz resonator in which the pipe (4) and the pipe (4) are connected through a communication hole (7) with a cross-sectional area S, and the attenuation [Ldb] in this case is expressed by the following equation.

db-10・10g111(1+ρ112・C2//I
S1'×(ρ3.・ω/Co-pH-C2/■・ω)2
) where ρ. - Density of the solvent, Co - Acoustic conductivity of the resonator, ω - Angular velocity of the sound wave, ■ - Volume of the resonator.

An actual example of this type of muffler is one in which a pipe (4) with a number of holes (8) is inserted into a cavity (5), as shown in FIG. In this case, a hole with a small diameter is effective in reducing the high frequency range, and a hole with a large diameter is effective in reducing the low frequency range.

Therefore, by sequentially providing holes from large diameter holes to small diameter holes, it is possible to muffle the entire audible frequency range, and it is also possible to select the frequency range to be muffled depending on the diameter of the holes.

By the way, these silencers are usually manufactured by welding and caulking iron or stainless steel plates and tubes. Furthermore, in recent years, a silencer manufactured by welding an Al alloy has been proposed. This Al alloy silencer is characterized by being lightweight and having excellent weather resistance.

[Problem to be solved by the invention]

However, the Al alloy silencer manufactured by welding has a problem in that it is difficult to make the internal structure complicated, and the manufacturing cost is high because the manufacturing process is complicated.

[First Step to Solve the Problems] In view of this, and as a result of various studies, the present invention provides a method for manufacturing an AA alloy silencer that can simplify the manufacturing process and reduce costs.

That is, the present invention provides a cavity made of A72 alloy in the middle of an exhaust pipe line, and in manufacturing a silencer having one or more Al alloy elements inside the cavity, the cavity part constituent members and the elements inside the silencer are It is effective to use the so-called vapor phase brazing method as a brazing method.

[For production]

The present invention relates to the manufacture of a silencer having a complicated internal structure as described above, and is characterized in that it employs the 1-method, which allows all components to be joined at once.

Now - inboard brazing of aluminum or aluminum alloys will be described. In this brazing, aluminum alloys or aluminum alloy members to be joined are fixed together through a braze having a melting point lower than that of aluminum, etc., to form an assembly, and the melting point is higher than the melting point of the braze,
This is done by heating to a temperature lower than the melting point of the aluminum or aluminum alloy members to be joined. As the brazing material, Aid-8i alloy is generally used, and its shape can be plate-shaped, wire-shaped, powder-shaped brazing pads, or laminated pads made of a core material made of aluminum or aluminum alloy coated with this brazing material. It is used in the form of a plating sheet (hereinafter referred to as a praising sheet).

The brazing method is J-Flux brazing (J-Flux brazing method, which uses flux to remove the oxide film on the surface of the part to be soldered), and Vacuum brazing without using J-Flux brazing method.
ked( is usually used.

The above flux brazing method: For example, immersion brazing is a method in which the assemblies to be joined are immersed in a molten chloride-based flux and heated for brazing. Apply system flux and braze in a furnace ζ]
There are methods such as heating in a furnace. However, since this chloride-based flux is corrosive to aluminum, it must be completely removed by cleaning after brazing, and since the internal structure of silencers is complex, the cleaning process is difficult. becomes complicated.

On the other hand, vacuum brazing, in which the assembly to be joined is placed in a vacuum and heated during brazing, does not require cleaning as a post-process according to the law, and the surface of the parts after brazing is also good. However, there are restrictions on equipment such as the need for high vacuum and restrictions on metal materials.

Also, in recent years, a method of brazing in a furnace using fluoride flux has been used. This uses a mixture of A/F, which is non-hygroscopic and non-corrosive to aluminum, as a flux, which is suspended in water and applied to the surfaces of the assemblies to be bonded. This method is applied to the surface and brazed, and its feature is that since it uses non-corrosive flux, there is no need for a post-processing process to remove the flux, and it can also be applied to the manufacturing method of the present invention for silencers. It is. However, this soldering method requires a coating and drying process to deposit the flux on the surface of the assembly, and the applied flux is used during the assembly while transporting the assembly to the next process. Many of the fluxes fall off from objects, and as a result, the yield of effectively used flux decreases. In addition, since brazing leaves flux residue unevenly on the surface of the joint after brazing, vacuum brazing has a dirty surface compared to the method and is inferior in commercial value. When applying chromate treatment or black paint treatment, there is also the disadvantage that the effect becomes non-uniform and the effect cannot be fully exhibited.

Recently, it has become necessary to apply flux to the entire surface of the members to be joined (potassium fluoroaluminate complexes such as KA6F, cesium fluoroaluminate complexes such as Cs A (1,F, +), KBF4,
KZnF, , Tg Sr] F 3
, K 2 Z r F t, Ig, SiF
,, so-called gas phase brazing (=
The J-ke method has been developed.

According to the law, this brazing method has a small amount of flux on the surface of the product, and the surface is clean. equipment can be provided.

Therefore, manufacturing Aff alloy silencers using this vapor phase brazing method is most advantageous in terms of product cleanliness and manufacturing cost.

〔Example〕

Next, examples of the present invention will be described. Note that all percentages below indicate overlapping percentages.

<Example> As shown in Fig. 5, 3003 alloy (Aff-0.1%
Cu-1,2%Mn alloy) is used as the core material, and B is placed on one side of the core material.
A/alloy plate made of BAlIPC clad with 4343 alloy (AA-7,5% Si alloy) is bent into a cylindrical shape. Inside the outer plate (1), there is an element (2) of 3003 alloy and on both sides. A side plate (3) is provided, and a cavity-type and resonance-type composite silencer is assembled by incorporating the above-mentioned pipe (4) made of IAlII'C with a large number of holes between them. It was fixed with.

This assembly was degreased with an organic solvent and K A 1! F. Powder was placed on a stainless steel tray on which 50 g of powder was placed per inner volume of the furnace. Furthermore, in Figure 5 (^
) KA/F powder was placed in an amount of 50 g per inner volume of the divided cavity (9) partitioned by elements. Part 1 - Oxygen partial pressure 1 mm 11 g, water vapor partial pressure 5
mm11g, replaced with argon gas, 610°
The tray was inserted into an electric furnace maintained at 610°C for 5 minutes to perform waxing. At this time, the powdered flux melts and evaporates while being heated to a temperature of 1° after being inserted into the furnace, and the brazing is sometimes effective because the flux vapor covers the assembly. It turns out.

After the above-mentioned brazing, the silencer was taken out of the furnace and the amount of flux 111 deposited on the surface was measured.The brazing conditions were also investigated and the results are shown in Table 1. Thereafter, chromate treatment and black coating were performed by a conventional method, and the adhesion properties are listed in Table 1 as chromate properties and paint properties.Furthermore, the present invention is based on the manufacturing cost when using the following conventional method. The manufacturing cost of the method was investigated and the reduction rate is shown in Table 1.

<Conventional Example> For comparison, a silencer was manufactured by assembling 3003 alloy plates and pipes by welding, and its characteristics were investigated (Example)
The same procedure as above was carried out, and the results are shown in Table 1.

As is clear from Table 1, the method for manufacturing a silencer according to the present invention can have a structure similar to that produced by welding, and has a chromate property.

The paintability was also good, there were no adverse effects due to manufacturing by brazing, and the manufacturing cost was further reduced by 20%.

1 [Effects of the Invention] As described above, according to the present invention, an Al alloy silencer having a complicated structure can be manufactured easily at low cost, and other industrially significant effects are achieved.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a simple cavity type silencer, Figure 2 is a schematic diagram of a cavity type silencer with an element inside, Figures 3 and 4 are schematic diagrams of a resonant cavity type silencer, FIG. 5 is a partially cutaway side view showing the composite silencer. 1-・Outer plate 5...Cavity part 2...Element 6...Resonator 3...Zydobrae-1
-7, 8...Communication hole 4...Vibe 9.
・Divided cavity part 2

Claims (2)

[Claims] (1) In manufacturing a silencer that has a cavity made of an Al alloy in the middle of the exhaust pipe and has one or more Al alloy elements inside, the members constituting the cavity and the elements inside the cavity are A method for manufacturing an Al alloy silencer characterized by integral brazing. (2) The method for manufacturing an Al alloy silencer according to claim (1), wherein a so-called vapor phase brazing method, in which brazing is performed in a non-oxidizing atmosphere in the presence of flux vapor, is used as the brazing method.