JP3709972B2 - Aluminum alloy spot joining method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spot welding method and apparatus for an aluminum alloy, and more particularly to a method for spot joining an aluminum alloy for joining aluminum and its alloy member when aluminum and its alloy are used for reducing the weight of various transportation equipment. And device . Here, the aluminum alloy member typically refers to a plate material or a shape material, but may be other than these, and point bonding can be applied to the mutual connection of the plate materials, the connection between the plate material and the shape material, or the like.
[0002]
[Prior art]
From the viewpoints of protecting the global environment and saving energy, it is required to reduce the weight of various equipment, especially the weight of transportation equipment such as automobiles. For exterior materials (panel materials) and other parts, conventional steel materials are made of aluminum and its alloys. Conversion to materials is being actively considered. In this case, various characteristics are required for the aluminum alloy material in comparison with the conventional steel material. Among these, the method of joining the aluminum alloy materials to each other is also an important issue. As for the structure of an automobile body used as a panel material, a monocoque structure in which plate press products are joined by resistance spot welding (spot welding) has become the mainstream.
[0003]
Until now, in resistance spot welding to aluminum alloy materials, spot welding methods using chromium copper electrodes and zirconium chromium copper electrodes used for spot welding to steel materials have been diverted, but aluminum alloy materials are more conductive than steel materials. Because of its high thermal conductivity, it is necessary to energize for a short time with a large current during spot welding. For this reason, in aluminum alloy material welding, electrode wear is more severe than in steel welding, and it is normal over a long period of time. There is a problem that it is difficult to form a perfect nugget.
[0004]
For this reason, joining of aluminum alloy materials by self-piercing rivets has been attempted. This joining method is a kind of mechanical joining in which steel rivets are driven into a plurality of stacked aluminum alloy materials, and has the advantage that the quality of the joint portion is more stable than resistance spot welding. There is a drawback that an expensive rivet is required as a member, and there is a possibility that poor bonding occurs depending on the wear state of the tool.
[0005]
In recent years, friction stir welding has been proposed as a butt joining method for aluminum alloy materials that have low heat input and little degree of softening or distortion. (Patent No. 2712838) In this method, a soft material such as an aluminum alloy material is abutted and restrained on a backing made of a hard material, and a press-fit pin of a friction welding tool harder than the soft material is protruded. The soft material is frictionally bonded to each other by press-fitting and moving while rotating at high speed to the mating portion, and the bonded portion is not melted.
[0006]
When the above friction joining method is applied to the joining of aluminum alloy materials, it can be expected that the joint quality is better than that of resistance spot welding or rivet joining, and a good joining state can be stably maintained. It is not clear whether the friction welding method can be applied to spot welding.
[0007]
[Problems to be solved by the invention]
The present invention has been made as a result of repeated testing and examination of a spot welding method using a friction welding method in order to eliminate the above-mentioned conventional problems in joining aluminum alloy materials, and its purpose is friction An aluminum alloy spot joining method and apparatus capable of stably maintaining a good joining state without pressing a press-fitting pin of a joining tool and moving it, and without a press-fitting hole of the press-fitting pin remaining in a joining portion. It is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a point joining method of an aluminum alloy according to claim 1 of the present invention is a method of spot joining a plurality of superposed aluminum alloy materials, and a plurality of superposed aluminum alloy materials. The step of press-fitting and stirring while rotating the press-fit pin of the friction welding tool harder than the aluminum alloy material , the step of removing the press-fit pin, and the press-fitting into the press-fit hole by the press-fit pin after the start of the remove step It is characterized by comprising an embedding step in which an aluminum alloy overflow portion overflowing outward with the press-fitting of a pin is pressed and fluidized by the friction welding tool .
[0009]
According to a second aspect of the present invention, there is provided the aluminum alloy spot joining method according to the first aspect , wherein the embedding step includes an overflow of the aluminum alloy overflow portion between the press-fit pin and the outer ring of the triple-structure friction welding tool. It is sealed in advance, and after the start of the step of removing the press-fit pin from the press-fit hole, the intermediate ring of the friction welding tool is pressed against the aluminum alloy material surface, and the aluminum alloy overflow portion is caused to flow into the press-fit hole.
[0010]
According to a third aspect of the present invention, there is provided the aluminum alloy spot joining method according to the first aspect , wherein the embedding step includes applying the aluminum alloy overflow portion overflowing outward to the front and back surfaces of the plurality of aluminum alloy materials. Pre-sealed between one press-fit pin and pressure ring in a heavy-duty friction welding tool, and after the start of the process of removing the other press-fit pin from the press-fit hole, push one press-fit pin back to the aluminum alloy material surface The aluminum alloy overflow portion is caused to flow in the press-fitting hole.
[0011]
An aluminum alloy point joining apparatus according to claim 4 is an apparatus for spot joining a plurality of stacked aluminum alloy materials, and a press-fit pin for press-fitting while rotating with respect to the aluminum alloy material, and the press-fit pin rotates. A triple-structure friction welding tool comprising an intermediate ring that is slidably fitted and an outer ring that is rotatably and slidably fitted to the intermediate ring. The aluminum alloy overflowing part which is arranged on one side of the combined aluminum alloy material and lifts the intermediate ring and overflows outward with the press-fitting of the press-fitting pin between the press-fitting pin and the outer ring in advance. After the start of the process of removing the press-fit pin from the press-fit hole by the press-fit pin, the intermediate ring is pressed against the aluminum alloy material surface, and the aluminum alloy overflow portion is inserted into the press-fit hole. Characterized by so as to motion.
[0012]
An aluminum alloy point joining device according to claim 5 is a device for spot joining a plurality of stacked aluminum alloy materials, a press-fit pin for press-fitting while rotating with respect to the aluminum alloy material, and the press-fit pin rotates. A dual-structure friction welding tool comprising a press ring that is slidably fitted, and the dual-structure friction welding tool is disposed on the front and back surfaces of the plurality of stacked aluminum alloy materials, An aluminum alloy overflow portion overflowing outward with the press-fitting of one press-fit pin is formed between the other press-fit pin and the pressure ring located on the opposite side of the one press-fit pin with respect to the plurality of aluminum alloy materials. After the process of removing one press-fit pin from the press-fit hole by the press-fit pin, press the other press-fit pin back to the aluminum alloy material surface, Bonding apparatus point of aluminum alloy, characterized in that so as to flow the aluminum alloy overflow portion.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. These illustrate preferred embodiments of the present invention and the present invention is not limited to these forms.
[0014]
1-5 is sectional drawing explaining embodiment in the case of carrying out spot joining of the aluminum alloy board | plate material by this invention. In the point joining method of the aluminum alloy of the present invention, first, a plurality of aluminum alloy plates 1 are overlapped. In FIG. 1, two aluminum alloy plates 1a and 1b are overlapped. Next, a friction welding tool 3 having a press-fit pin 2 having a press-fit length is press-fitted into all the aluminum alloy plates 1 as shown in FIG. The press-fit pin 2 is integrally attached to the rotary cylinder 4, and the press-fit pin 2 and the rotary cylinder 4 are made of a material that is harder than the aluminum alloy plate 1 and has heat resistance.
[0015]
When the press-fit pin 2 is press-fitted into the aluminum alloy plate 1 and stirred, the aluminum alloy overflow portion 6 overflows and the stirring portion 7 is formed by the amount corresponding to the press-fitting hole 5 being formed. As shown in FIG. 3, the friction welding is performed by pressing the tip portion of the press-fit pin 2 to the aluminum alloy plate 1b and pressing the stirring portion 7 with the shoulder at the lower end of the rotating cylindrical body 4, but press-fit as it is. When the pin 2 is pulled out from the press-fitting hole 5, as shown in FIG. 4, the press-fitting hole 5 remains vacant in the friction joint portion, which causes a problem in strength and may not be preferable in appearance. The step of embedding the press-fitting hole 5 with the aluminum alloy overflow portion overflowing outward with the press-fitting of the press-fit pin is essential. The embedding step of the press-fitting hole 5 is performed by a combined system of heat and mechanical means.
[0016]
A preferable press-fitting hole embedding step includes a step of removing the press-fit pin 2 and an aluminum alloy overflow portion 6 overflowing outward from the press-fit hole 5 during the press-fitting and stirring of the press-fit pin 2 after the start of the removal step. 5 and an embedding step of allowing the fluid to flow. That is, the removal process is the process shown in FIG. 4 and the embedding process is the process shown in FIG. 5, and the aluminum alloy overflow portion 6 around the press-fitting hole 5 is returned to the press-fitting hole 5.
[0017]
Next, FIG. 6-7, a description of another embodiment of the implantation process. The steps up to FIGS. 1 to 3 are performed in a similar manner, but differ in that a triple-structure friction welding tool 3a is used. In this case, in the friction welding tool 3 a, the press-fit pin 2 a is fitted in the sliding hole 11 of the intermediate ring 10 so as to be rotatable and axially movable, and the intermediate ring 10 is rotatable in the sliding hole 13 of the outer ring 12. The press-fit pin 2a and the intermediate ring 10 can be rotated separately by being fitted so as to be movable in the axial direction. Accordingly, while the backing material 14 is applied to the aluminum alloy plate 1 and the outer ring 12 is in contact with the aluminum alloy plate 1a, the steps from FIGS. 1 to 3 are performed. The aluminum alloy overflow portion 6 overflowing outward is slightly raised without being pressed by the intermediate ring 10 and is sealed between the press-fit pin 2a and the outer ring 12, and the press-fit pin 2a starts to rise from the press-fit hole 5 Thereafter, when the intermediate ring 10 is rotated and pressed against the surface of the aluminum alloy plate 1a, and the aluminum alloy overflow portion 6 is embedded in the press-fitting hole 5, a point friction joint as shown in FIG. 7 is formed.
[0018]
8 to 9 , still another embodiment of the embedding process will be described. The steps up to FIGS. 1 to 3 are carried out in the same manner, but differ in that a set of two friction welding tools 20 consisting of double-structure friction welding tools 20a and 20b is used. In this case, the friction welding tools 20a and 20b have a structure in which the outer ring 12 is removed from the friction welding tool 3a. That is, the press-fit pin 21 is fitted in the slide hole 23 of the press ring 22 so as to be rotatable and axially movable, and the press-fit pin 21 and the press ring 22 can be rotated separately. Accordingly, the friction welding tool 20b is applied as a backing material to the aluminum alloy plate 1b, and the steps from FIGS. 1 to 3 are performed, but the aluminum alloy overflow portion 6 overflowing outward from the press-fitting hole 5 in the process of FIG. The press-fitting pin 21b is slightly lowered and sealed between the press-fitting pin 21b of the friction welding tool 20b and the pressing ring 22b. When the aluminum alloy plate 1b is pushed back to the surface and the aluminum alloy overflow portion 6 is embedded in the press-fitting hole 5, a point friction joint as shown in FIG. 9 is formed.
[0019]
Examples for confirming the effects of the present invention will be described below.
Example 1
As shown in FIG. 6 , two aluminum alloy plates (material: 5182, tempering: O material, thickness: 1 mm) are overlapped, a steel backing is applied from the back side, and a triple-acting double acting type from the front side While rotating the friction welding tool, it was brought into contact with the surface of the aluminum alloy plate, the press-fitting pin was protruded, inserted into the aluminum alloy plate, and stirred at a rotational speed of 1000 rpm.
[0020]
The initial insertion length of the press-fit pin is 1.2 mm from the plate surface, and the intermediate ring is recessed 0.5 mm from the plate surface. After waiting for 1 second in this state, the intermediate ring is pressed against the plate surface while removing the press-fit pin. The point joining was performed. The double-acting friction welding tool used has a press-fit pin diameter of 4 mm, an intermediate ring diameter of 8 mm, and an outer ring diameter of 20 mm.
[0021]
The obtained point joint had no apparent defects such as a press-fitting hole left because the surface was recessed within 0.1 mm, and a nugget (stirring portion) having a diameter of 5 mm was formed. As a result of the shear tensile test of this joint portion, the strength of 120% or more of the resistance spot welded joint having the same diameter nugget was maintained.
[0022]
Example 2
As shown in FIG. 8 , two aluminum alloy plates (material: 6111, tempering: T4, thickness: 0.8 mm) are overlapped, and the vicinity of the joint is sandwiched and fixed by a positioning jig. The double-acting friction welding tool (press-fit pin diameter: 4 mm, pressing ring diameter: 8 mm) having a heavy structure is in contact with the double-layered plate while rotating, and the press-fit pin of the double-acting friction welding tool on the surface side is 1 mm. It was made to protrude, and it inserted in the aluminum alloy plate, and stirred at the rotation speed 1500rpm.
[0023]
At the same time, the press-fitting pin of the double-acting friction welding tool on the back side is initially recessed by 1 mm, and the press-fitting pin of the double-acting friction welding tool on the front side is pulled out to a depth of 0.1 mm from the plate surface. The press-fitting pin of the double-acting friction welding tool was pressed to a depth of 0.1 mm from the plate surface, and spot-joined.
[0024]
The obtained point joint had no apparent defect, and a nugget having a diameter of 4.6 mm was formed without leaving a press-fitting hole in the joint. As a result of the shear tensile test of the joint portion, the strength of the resistance spot welded joint having the same diameter nugget was maintained at 150% or more.
[0025]
【The invention's effect】
As described above, according to the first aspect of the present invention, since the press-fitting hole generated in the joining process is embedded in the aluminum alloy overflow portion, a joining state in which the joining interface is continuous is obtained, the joint quality is good, and the fatigue strength is excellent. A joint can be obtained. In addition, the aluminum alloy overflow that overflows from the press-fitting hole during the joining process is pressed with a friction welding tool and embedded in the press-fitting hole, so that in addition to the above effects, swelling around the press-fitting hole that occurs during the joining process is prevented. And a point joint with a good surface condition can be obtained.
[0026]
According to the second and fourth aspects of the present invention, the flow area of the overflowing portion of the aluminum alloy overflowing from the press-fitting hole in the joining process is regulated in advance, and the press-fitting pin is pulled out from the press-fitting hole generated in the joining process and the press-fitting hole is made of aluminum. In addition to the above effects, the alloy overflow part is flown and embedded, so it is possible to perform the joining and the press-fitting hole continuously, which is highly efficient, and the flow area of the aluminum alloy overflow part is regulated. Therefore, a point joint with a good surface state can be obtained, and the structure of the backing jig can be simplified.
[0027]
According to the third and fifth aspects of the present invention, the flow area of the aluminum alloy overflow portion that is about to overflow from the press-fitting hole in the joining process is regulated in advance so as to be the opposite surface of the press-fitting hole. Pull out the press-fit pin from the generated press-fit hole and press the press-fit pin on the opposite surface to flow the aluminum alloy effluent on the opposite surface to flow and embed it. It is highly efficient because it can be performed continuously, and joints are formed over the front and back surfaces, a stable nugget diameter is obtained, the joint strength is high, and the front and back surface point joints are in good condition. Is obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view (first step) for explaining an embodiment of a point joining method of the present invention.
FIG. 2 is a cross-sectional view (second step) for explaining an embodiment of the point joining method of the present invention.
FIG. 3 is a cross-sectional view (third step) for explaining an embodiment of the point joining method of the present invention.
FIG. 4 is a cross-sectional view (fourth step) for explaining an embodiment of the point joining method of the present invention.
FIG. 5 is a sectional view (fifth step) for explaining an embodiment of the point joining method of the present invention.
FIG. 6 is a cross-sectional view for explaining another embodiment of the point joining method of the present invention.
7 is a cross-sectional view showing a state after joining by the point joining method shown in FIG. 6;
FIG. 8 is a cross-sectional view for explaining still another embodiment of the point joining method of the present invention.
9 is a cross-sectional view showing a state after joining by the point joining method shown in FIG. 8. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1a, 1b Aluminum alloy plate 2, 2a, 21, 21a, 21b Press-fit pin 3, 3a, 20, 20a, 20b Friction welding tool 4 Rotating cylindrical body 5 Press-fit hole 6 Aluminum alloy overflow part 7 Stirring part 10 Intermediate ring 11 , 13, 23 Slide hole 12 External ring 14 Backing material 22, 22a, 22b Press ring

Claims (5)

A method of spot-joining a plurality of stacked aluminum alloy materials, in which a plurality of stacked aluminum alloy materials are pressed and stirred while rotating a press-fit pin of a friction welding tool harder than the aluminum alloy material. And the step of removing the press-fit pin, and after the start of the step of removing, the aluminum alloy overflowed portion overflowing outwards due to the press-fit of the press-fit pin is inserted into the press-fit hole by the press-fit pin by the friction welding tool. An aluminum alloy point joining method comprising an embedding step of pressing and flowing . In the embedding step, the aluminum alloy overflowing portion overflowing outwards is previously sealed between the press-fit pin and the outer ring in the triple-structure friction welding tool, and after the start of the step of removing the press-fit pin from the press-fit hole , an intermediate ring of the friction welding tool is pressed against the aluminum alloy material surface, the joining method in terms of claim 1, wherein the aluminum alloy, characterized in that flowing the aluminum alloy overflow portion press-fit hole. In the embedding step, the aluminum alloy overflow portion overflowing outward is applied to the front and back surfaces of the plurality of aluminum alloy materials, and between the one press-fitting pin and the pressing ring in the double structure friction welding tool. And after the start of the process of removing the other press-fit pin from the press-fit hole, the one press-fit pin is pushed back to the aluminum alloy material surface, and the aluminum alloy overflow portion is caused to flow into the press-fit hole. The point joining method of the aluminum alloy of Claim 1 . An apparatus for spot-joining a plurality of stacked aluminum alloy materials, a press-fit pin for press-fitting while rotating with respect to the aluminum alloy material, an intermediate ring in which the press-fit pin is rotatably and slidably fitted, A triple-structure friction welding tool comprising an outer ring in which the intermediate ring is rotatably and slidably fitted is provided, and the triple-structure friction welding tool is disposed on one side of the plurality of stacked aluminum alloy materials. The intermediate ring is raised and the aluminum alloy overflow that overflows outward with the press-fit of the press-fit pin is confined between the press-fit pin and the outer ring in advance. After the start of the pin removal process, the aluminum ring is pressed against the aluminum alloy material surface so that the aluminum alloy overflow portion flows in the press-fitting hole. Bonding apparatus point of the alloy. A device for spot-joining a plurality of stacked aluminum alloy materials, comprising a press-fit pin for press-fitting while rotating with respect to the aluminum alloy material, and a press ring on which the press-fit pin is slidably fitted. A double-structure friction welding tool is provided, and the double-structure friction welding tool is disposed on the front and back surfaces of the plurality of stacked aluminum alloy materials, and outwards with the press-fitting of one press-fit pin. The overflowing aluminum alloy overflow portion is sealed in advance between the other press-fit pin and the press ring located on the opposite side of the one press-fit pin with respect to the plurality of aluminum alloy materials, and the press-fit hole by the press-fit pin After the start of the process of removing one press-fit pin from the other, the other press-fit pin is pushed back to the aluminum alloy material surface so that the aluminum alloy overflow portion flows into the press-fit hole. Bonding apparatus point of aluminum alloy, characterized in that.

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