JPS6062653A - Tank-like part such as intake system surge tank in internal-combustion engine - Google Patents

Abstract

PURPOSE:To obtain a uniform bead with high quality and obtain a tank-like part with high airtightness by forming a joint so that the surface of a cover plate is located nearer to the MIG torch side than the opening surface of the tank proper. CONSTITUTION:A surge tank 1 is formed by MIG-welding a cover plate 3 made with an aluminum extended plate to the tank proper 2 made by die-casting aluminum. In welding the cover plate 3, the surface 12 of the cover plate 3 is made higher than the surface 14 of the thick section 13 and is located near to the MIG torch 4 side when the cover plate 3 prior to welding is matched with the tank proper 2. Thereby, the cover plate 3 at a higher position is first dissolved, and the heat transfer to the opening surface side of the tank proper 2 and dissolution quantity can be kept little to the utmost.

Description

DETAILED DESCRIPTION OF THE INVENTION It is common practice to manufacture light alloy parts for internal combustion engines by die casting. One such example is the intake system surge tank, and it is important to properly attach the lid plate to the tank body. The present invention relates to such a tank-shaped part of an internal combustion engine,
The feature is that a joint structure suitable for the characteristics of MIG welding is provided to the joint between the die-cast tank body and the expanded aluminum cover plate.

When the tank body is made of die-cast aluminum alloy, the molten metal flows into the mold cavity at high speed and high pressure, so gas generated from air and mold release agent enters the molten metal during the transition period of flow. This results in the formation of fine cavities.

Although some of the gases encapsulated in metals are occasionally visible to the naked eye, the majority of them are scattered in such a way that they can be seen even under a microscope. This gas is then confined under high pressure.

When MIG welding is performed on a tank body in a gaseous state as described above, when the die-casting base material is melted, fine bubble forces are concentrated and the koji is violently released, resulting in blowholes occurring in the weld bead due to bubble bursting. Or, breaks may occur in the bead, which should run smoothly. If there is such a defect in the surge tank or the like of an internal combustion engine, intake air leakage will occur, which will impede the desired engine performance.

Furthermore, such bubble bursting is caused by C# Toka 7. The flow of the arc is disturbed, the original shielding function becomes insufficient, and the shape of the arc itself becomes abnormal.This causes problems such as the inability to obtain uniform and high-quality beads.

Hereinafter, the present invention will be described in detail according to an embodiment of the drawings taking a surge tank as an example. MIG welded.
Welding is performed by bringing the MIG1, -chi 4 close to the position shown in the figure, and a weld bead 5 as shown in FIG. 2 is formed. When the cover plate 3 is aligned with the tank body 2, the positional relationship between the two must be set to a predetermined relationship as described later, so a stepped portion 6 is provided as shown in FIG.

FIG. 4 shows a case where a support protrusion 7 is provided on the inner surface of the tank body 2 instead of the stepped portion 6. An inlet pipe 8 is integrally formed in the tank body 2, and an outlet hole 9 is formed in the cover plate 3.
are opened, and intake pipes 10 and 11 are connected to each of them.

The dimensions of the surge tank L are 210mm wide x 180mm tall.
.

The depth is 55+++m, the tank body 2 has a wall thickness of 4.5mm, and the XIX boot 3 has a wall thickness of 4mm. In addition, Fig. 5 is an enlarged sectional view of the welding local area, and the dimensions of each part are a''4
．． 5m1r, 1)=4m'J c=8mm, d:=l
+++m1e=8rnm, (=near mra).

The most important point in the welded joint structure shown in the figure is the provision of dimension g. This is the position where the surface 12 of the lid plate 3 is higher than the surface 14 of the thick part J3 when the lid plate 3 is aligned with the tank body 2 as shown in FIGS.
That is, the positional relationship between the two is set so that the position is close to the MIG torch 4 side. In the case of FIG. 5, the height difference g is 1 mm. Note that the surface 14 means the opening surface of the tank body.

In Fig. 5, setting e = 8 WImof' = = 4 mm and forming 11 in the thick part at the part indicated by 13 is because the thermal mass of the technical part is set large and the die-cast member side is This is to reduce the amount of dissolution.

The MIG +--chi 4 in FIG. 5 is located at a distance of nIF from the product, and the welding wire 15 is attached to the outer peripheral edge of the lid plate 3, as is clear from the weld bead 5 in FIG. The trajectory is set to move over the surface 12 close to and along the outer periphery. Although this locus position changes slightly depending on various conditions, here it is set to Il = 1 mm. The installation position of the welding area is set so that it is horizontal, taking into consideration the flow phenomenon of molten metal.

The conditions for MIG welding, the chemical composition of the tank body and the lid plate, etc. are extremely common, but are exemplified as follows for reference.

Melting conditions: Arc current 120A Arc voltage 20V Arc pulse 60 cycles Wire diameter + 1.241m Material JIS Z8232 A4048 Shielding gas Ar, Ar + HeAr + 02, etc. Shielding gas flow rate 201! /min Torch layer transfer 1 speed (average) 60cm/min Tank body material: JIS H2BO3ADC12 with some aluminum casting scraps Expanded aluminum material for lid plate: JIS I (4000A105
The state of change in the OP weld local area will be explained with reference to FIGS. 6 to 8. At the initial stage of melting as shown in FIG. 6, the molten pool is a relatively narrow region and the amount of metal melt is small. What is particularly noteworthy is that the molten pool 16 remains within the range of the cover plate 3 at this stage because the trace of movement lh of the welding wire 15 is positioned as shown in FIG. As the melting further progresses and the molten pool 16 becomes wider and deeper, the amount of molten metal also increases as shown in FIG. In this case, the surface 12 of the lid plate
Since the water is closer to the M1'G)-chi side than the surface 14 of the thick portion, it flows down to the surface 14 side located at a lower position and becomes in a state where it covers a part of the surface 14. In this state,
Since the amount of heat to the thick portion 13 side is also small, the surface 140 portion is not melted. As such welding action further progresses, the surface 14 side is also melted as shown in FIG. 8, metal is also supplied from the welding wire, and the material gradually solidifies into a cross-sectional shape as shown in the same figure.

According to the present invention, since the joint structure is such that the surface of the lid plate is positioned closer to the MIG torch side than the opening surface of the tank body, the following effects can be achieved. In other words, by appropriately determining the dimensions as shown in Figure 5, melting occurs preferentially starting from the lid plate located one step higher, and heat transfer to the opening surface of the tank body and the amount of melting there are minimized. As a result, the number of bubbles ruptured on the die-casting material side can be minimized and kept to a small scale. Furthermore, the fluid metal at the end of the lid plate is
Since it is a molten metal that has been sufficiently heated and has good fluidity, and does not contain gas, even if air bubbles from the die-casting material burst at the bead, that part will be immediately compensated for. This phenomenon occurs, improving the welded appearance of the surge tank and providing a highly airtight part. Further, due to the above-described effects, there is no disturbance in the shielding gas flow, and a highly stable arc can be obtained.

The present invention rationally solves the original problem through the above-described structural action and provides an excellent tank-shaped component.

[Brief explanation of the drawing]

Figure 1 is a side view of the surge tank, Figure 2 is a plan view of the same, Figures 3 and 4 are (3)-(3) sectional views of Figure 2,
FIG. 5 is an enlarged sectional view of the welding local area, and FIGS. 6 to 8 are sectional views showing the melting process of the welding local area. 2. Tank body, 3. Lid plate, 12. Lid plate surface, 14. Opening surface, 4. G l--chi. Applicants: Daihatsu Motor Co., Ltd.) 61°C Figure 7

Claims (1)

[Claims] A cover plate made of wrought aluminum is MIG-welded to a die-cast aluminum tank body, and the welding joint between the two members is arranged so that the surface of the cover plate is MIG-welded than the opening surface of the tank body.
G. A tank-shaped part such as an intake system surge tank in an internal combustion engine, characterized by being configured to take a position close to the torch side.