JPH0658214A - Manufacture of intake manifold - Google Patents

Abstract

PURPOSE:To save labor of flux application and improve external appearance and surface treatment characteristic by using Al solder material which includes flux in soldering of each component. CONSTITUTION:A product made of Al, Si, flux fluoride is provided, wherein an amount of Si is 3 to 15wt.% in respect to an amount of total elements other than the flux fluoride. The ratio of the amount of the elements other than the flux fluoride in respect to the amount of the flux fluoride is 9.9:0.1 to 70:30. Al solder material including flux whose density is a value of 90% or more of a theoretical value is arranged on a connection part between an intake tube 3 made of Al estensive material and a plenum made of Al extensive material, and an intake flange 4 made of Al cast material. Soldering is carried out by heating them. It is possible to manufacture a product having components excellent of soldering performance and surface treatment characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an intake manifold made of aluminum, which is used in, for example, an automobile engine and in which a plurality of intake tubes are brazed to a plenum and an intake flange.

[0002] In this specification, the term aluminum is used to include aluminum and its alloys.

[0003]

2. Description of the Related Art As illustrated in FIG. 1, an intake manifold (1) made of aluminum is integrally provided around a hole formed in a peripheral wall of a main pipe (5) of a plenum (2). A hole formed by fitting one end surface of the intake tube (3) bent into a hairpin shape to the joint portion (8) and brazing the other end surface of the intake tube (3) to the intake flange (4) It is manufactured integrally by being brazed to be fitted around the joint and fitted to the joint (12). Then, such brazing is performed, for example, by supplying a brazing material to the joint portion, applying a flux suspension to the joint portion, and heating in a non-oxidizing atmosphere.

By the way, conventionally, each component member of such an intake manifold has been manufactured by a casting method. However, since the surface of the cast product is rough, air is fed from the open end of the plenum (2). Due to the large air resistance, the intake efficiency is poor and the weight is heavy. Therefore, by using a wrought material such as A6000 series aluminum alloy having excellent plastic workability, an intake manifold is manufactured which is improved in smoothness of the inner surface of each member and processed into a thin wall to reduce the weight. It became so. However, although the plenum (2) and the intake tube (3) having a relatively simple shape can be formed by plastic processing such as extrusion molding using the wrought material as a material, the intake flange (4) has a complicated shape. Cast products are still used because they are extremely difficult to manufacture by plastic working. Further, since the intake flange (4) is a member required to have heat resistance, a heat-resistant aluminum casting material containing Mg such as D712 alloy is used.

[0005]

However, in the brazing method in which the brazing material and the flux are supplied separately, not only is it difficult to apply the flux, but also sufficient flux is applied to the joint. There is no choice but to use a large amount of flux, and an excess amount of flux remains on the surface of the brazed product after brazing. Then, in order to maintain the appearance quality of the brazed product and prevent the deterioration of the surface treatment property, the residual flux must be removed by washing. In particular, in the case of brazing an intake flange formed of a heat-resistant aluminum casting material containing Mg and the intake tube, an excessive amount of flux reacts with Mg to cause a cotton-like reaction such as MgF ₂ or KMgF _3. A product is formed and adheres to the surface of the brazed product, and this reaction product not only deteriorates the appearance quality and surface processability like the above residual flux, but also deteriorates the flux effect and hinders brazing itself. However, the problem that air leakage of the intake manifold is caused is added.

In order to solve the above-mentioned problems, the present invention manufactures a product excellent in brazing property, appearance quality and surface treatment property, and at the same time, an intake manifold which can simplify the manufacturing process. It is intended to provide a manufacturing method.

[0007]

In order to achieve the above-mentioned object, the method for manufacturing an intake manifold of the present invention comprises Al, S and
i, including fluoride flux, Si content is 3 to 15 wt% with respect to the total content of elements excluding fluoride flux
%, And the total weight of the elements excluding the fluoride-based flux and the fluoride-based flux is 99.9: 0.1 to 7 by weight ratio.
An intake tube (3) made of an aluminum wrought material and a flux-containing Al brazing filler metal, which is contained at a ratio of 0:30 and has a density of 90% or more of the theoretical value, at both ends of the intake tube (3), respectively. It is characterized in that it is arranged at an interconnecting portion with a plenum (2) made of an aluminum wrought material and an intake flange (4) made of a heat-resistant aluminum casting material to be connected and brazed by heating these. is there.

In the above-described flux-containing Al brazing material composition, if the Si content is less than 3 wt% or more than 15 wt% with respect to the total content of elements excluding fluoride flux, the liquidus of the brazing material becomes high. Brazing becomes difficult.
Therefore, the Si content must be specified to be 3 to 15 wt% with respect to the total content of the elements excluding the fluoride-based flux. Particularly preferable Si content range is 6 to 12.
wt%. In addition to Si, Cu and / or Zn may be mixed in order to improve the strength of the brazing material. The content of Cu is 0.05 to 0.05 with respect to the total content of elements other than the fluoride-based flux in the brazing material composition.
10 wt% and Zn; 0.05 to 10 wt% are preferable.

The kind of the above-mentioned fluoride-based flux is not particularly limited, and is, for example, 45.8% KF-54.2.
% AlF ₃ , eutectic composition or a complex mixture containing a composition range close thereto, KAlF ₄ , K
A complex of ₂ AlF ₅ and K ₃ AlF ₆ may be used.

In the flux-containing Al brazing material composition as described above, the total weight of the elements excluding the fluoride-based flux and the fluoride-based flux is 99.9: 0.1 by weight.
It must be specified in the range 70:30. When the fluoride flux is less than 99.9: 0.1, sufficient flux effect is not exhibited and brazing becomes difficult, while when it exceeds 70:30 and the fluoride flux is increased, both are mixed. Solidification becomes difficult, and flux content A
This is because it becomes difficult to manufacture the brazing filler metal itself. A preferable ratio of the total amount of elements excluding the fluoride-based flux and the fluoride-based flux is 99.9: 0.1-85: by weight.
15 and particularly preferably 98: 2 to 90:10.

The flux-containing Al brazing material used in the present invention is generally produced by mixing Al powder, Si powder, flux powder and the like and solidifying the mixture by hot pressing or the like. Normally, the density of the flux-containing Al brazing material becomes smaller than the theoretical value calculated from each of Al, Si and the flux alone due to the residual of the internal air, but in the present invention, it should be 90% or more of the theoretical value. I have to. When the density of the flux-containing Al brazing material is less than 90%, although the material powder is solidified, there is a risk that it will be brittle due to pore communication with the inside, and subsequent secondary processing is also difficult and practical. The function as the flux-containing Al brazing material becomes poor. Particularly preferably, the density of the flux-containing Al brazing material is 95% or more of the theoretical value. Further, in order to densify the brazing filler metal structure, it is preferable to finely pulverize each material powder, the Al powder has an average particle diameter of 44 μm or less, and the Si powder has an average particle diameter of 5 μm.
Hereinafter, the flux powder preferably has an average particle size of 30 μm or less. It should be noted that Al, Si, etc. do not necessarily have to be used alone as a starting material of the flux-containing Al brazing material, and Al-Si alloy powder may be used.
Moreover, you may use these together.

The heating method in the present invention is not particularly limited, and a typical heating method is heating in a furnace in a non-oxidizing atmosphere.

[0013]

[Function] Flux-containing Al used in the present invention
Since the brazing filler metal contains a fluoride-based flux uniformly in the brazing filler metal, one end of the intake tube (3) made of aluminum wrought material and the plenum (2) made of aluminum wrought material By arranging at the connection part and the connection part between the other end of the intake tube (3) and the intake flange (4) made of heat-resistant aluminum casting material, and heating, the flux is evenly supplied to the joint part at the same time as the brazing material. As a result, uniform brazing with excellent bonding strength is achieved. In addition, brazing with a fixed amount of brazing material inevitably results in the use of a constant and appropriate amount of fluoride-based flux, and no residual flux due to an excessive amount of flux occurs. In particular, even when the intake flange (4) made of a heat-resistant aluminum casting material containing Mg and the intake tube (3) are brazed, the flux supplied to the joint portion does not become excessive.
No reaction product of the system is produced.

In the present invention, the plenum (2), the intake tube (3) and the intake flange (4).
Since good brazing is performed as described above, it is possible to manufacture an intake manifold without air leakage due to defective brazing. Further, since no residual flux is generated in addition to the Mg-F-based reaction product, the deterioration of the appearance quality and the surface treatment property due to these do not occur.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific embodiment of the method for manufacturing an intake manifold of the present invention will be described with reference to the drawings.

Prior to the manufacture of the intake manifold, a flux-containing Al brazing material used for brazing was manufactured by the method described below.

As a starting material, Al having an average particle size of 44 μm
Powder, Si powder having an average particle size of 5 μm and average particle size of 16 μ
m eutectic powder of 45.8% KF-54.2% AlF ₃ was used. First, the weight ratio of these material powders is 18 (A
l): 2 (Si): 5 (flux)
Mix and stir at room temperature, and each material contains the desired flux A
A mixed powder uniformly mixed in the composition ratio of the brazing filler metal was prepared, and the mixed powder was filled in a cylindrical A1100 alloy container having an outer diameter of 3 inches and a length of 200 mm. This mixing ratio corresponds to a total amount of elements other than flux in the mixed powder, that is, a Si compounding amount of 10 wt% with respect to the total amount of Al and Si, and a total amount of Al and Si in the mixed powder, in other words, in the present invention. The total weight of the elements excluding the fluoride flux and the fluoride flux corresponds to 80:20 by weight. Next, the container was placed in a furnace at 500 ° C., and the inside of the furnace was evacuated to a vacuum of 1 mmHg or less to degas the filled mixed powder. In addition, 48
When hot-pressed at a maximum pressure of 400 tons using a hot press at 0 ° C., the compact was pressed and integrated with the container to have a height of 110 mm. Then, after removing the container pressure-bonded to the outside of this molded body by cutting, it was extruded by a hot extruder at 500 ° C. into a rod of 2.6 × 4.9 mm to obtain a flux-containing Al brazing material. . This flux-containing Al brazing material had a dense structure with a density of 98% or more of the theoretical density.

While making the flux containing Al braze material, the intake manifold (1) as shown in FIG.
Plenum (2) and intake tube (3)
And each member of the intake flange (4) was manufactured.
As shown in FIG. 2, the plenum (2) has an A60
One end side of a tubular material obtained by extrusion molding using 63 aluminum alloy as a material is closed in a hemispherical shape to form a main pipe (5), and four bulged portions are provided in series on the peripheral wall of the main pipe (5) by bulge molding. Further, these bulging portions were made by forming holes (6) and performing post-processing such as burring to provide a joint portion (8) communicating with the main pipe (5) and having an expanded pipe portion (7) at the tip. . The intake tube (3) was manufactured by bending an extruded pipe material into a hairpin shape using A6063 aluminum alloy as a material.
Further, as shown in FIG. 3, the intake flange (4) is made of a D712 heat-resistant aluminum alloy containing Mg as a material and is provided around the hole (10) around the holes provided in series in the substrate portion (9). It was manufactured by casting into a shape in which a connecting portion (12) having a pipe expanding portion (11) at the tip was provided in a protruding manner. Reference numeral (13) in FIG. 1 is a flange for attaching the intake manifold (1) to the main body of the air supply device.

One end side of the intake tube (3) manufactured as described above is fitted into the expanded portion (7) of the joint portion (8) of the plenum (2) (see FIG. 2), and the other end side is taken in. The flange (4) is fitted into the expanded portion (11) of the joint portion (12), and the flux-containing Al brazing material is formed into a ring shape and placed at each joint portion, and the temperature is 600 ° C. × 15 minutes in a furnace under N ₂ gas atmosphere. Brazed. As a result, each joint, especially even the Mg-containing D712 heat-resistant aluminum casting material, which is difficult to braze by the usual flux brazing method, is brazed well, and the brazed product surface is clean without any flux remaining. So it didn't need to be washed.

In the method of manufacturing the flux-containing Al brazing material used in this example, the A1100 alloy having a composition different from that of the brazing material was used as the container material for filling the mixed powder of the brazing material. It may be formed of an alloy having substantially the same composition or composition excluding the flux. By using such a container, hot molding can be performed in the same manner as in this example, and extrusion molding can be performed without removing the container part from the hot-pressed molded body.

[0021]

As described above, according to the present invention, in the brazing of each member constituting the intake manifold, by using the Al brazing material containing the flux, it is possible to save the labor of applying the flux, and Even if the Mg-containing aluminum material is used for the constituent members, it is possible to manufacture an intake manifold excellent in bonding property, appearance quality, and surface treatment property by uniformly supplying an appropriate amount of flux to the bonding portion.

Further, since a necessary and proper amount of flux can be supplied to the joint portion without using a large amount of flux, the residual flux and the reaction product between the flux and Mg are eliminated and the cleaning step after brazing is performed. Is eliminated, the flux applying step can be omitted, the brazing process can be simplified, and the intake manifold production process can be simplified.

[Brief description of drawings]

FIG. 1 is an external perspective view of an intake manifold in this embodiment.

FIG. 2 is a vertical sectional view of a plenum according to the present embodiment.

FIG. 3 is a vertical cross-sectional view of an intake flange in this embodiment.

[Explanation of symbols]

 2 ... Plenum 3 ... Intake tube 4 ... Intake flange

Claims (1)

[Claims] 1. An element containing Al, Si, and a fluoride-based flux, having a Si content of 3 to 15 wt% with respect to the total content of the elements excluding the fluoride-based flux, and excluding the fluoride-based flux. A flux-containing Al which contains the total and the fluoride-based flux in a weight ratio of 99.9: 0.1 to 70:30 and has a density of 90% or more of the theoretical value.
The brazing filler metal is an intake tube (3) made of an aluminum wrought material, a plenum (2) made of an aluminum wrought material to which both ends of the intake tube (3) are connected, and an intake flange made of a heat-resistant aluminum cast material ( 4) A method for manufacturing an intake manifold, characterized in that the intake manifold is arranged at an interconnection portion with (4) and is brazed by heating these.