JP2002120077A - Spot joining method, spot joining apparatus and joined materials - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spot joining apparatus, with which reduction in plate thickness caused by a recess due to a pin unavoidably developed with spot joining using friction stir is compensated, and to provide a spot joining method and joined materials. SOLUTION: A friction stir welding equipment 1 pushes the pin 8 against a joining point in two piled-up sheets of works W1, W2 while rotating a joining tool 7 having the pin 8 projecting from the tip thereof. Thus, the pin 8 is inserted into the joining point with the friction heat and a base metal is stirred with the rotation to induce plastic fluid. After stirring for a prescribed time, the joining is performed in the plastic fluid zone by pulling out the pin 8 to form the recess 16 due to the pin at the joining point. In the recess 16, thermosetting synthetic resin 17 is filled and hardened. The hardened resin 17 is integrated with the base metal and the shortage of strength caused by the locally reduced thickness is compensated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spot welding method for spot welding workpieces by friction stir welding.
The present invention relates to a spot joining apparatus and an object to be joined.

[0002]

2. Description of the Related Art Spot welding using friction stirrer is performed in two steps.
A plurality of works are placed one on top of the other, and the joining tool having a pin at the tip is lowered while rotating at a high speed, and the pin is pressed against the joining point of the work. Then, the pressing portion is softened by the friction due to the rotation, and the pin is inserted. By further rotating, the vicinity of the joining point is agitated by the inserted pin, and plastic flow is induced. After stirring for a predetermined time, when the joining tool is raised and the pin is pulled out, the two workpieces are joined at the joining point. In this way, the lap joint can be joined at the spot.

[0003]

In the case of spot welding using friction stir, a pin is inserted into a joining point and joining is performed.
A pin recess in the form of a pin remains in the part where the pin has been pulled out. In friction stir welding, a plastic flow is induced in the base material near the joining point with a pin, and the two workpieces near the joining point are joined by joining, so the pin recess formed only at the joining point Does not affect the macro-strength of the joint,
Locally, the thickness is reduced. Therefore, for example, when this portion is pierced from the outside with a needle-like thin object, a through-hole is easily formed, and airtightness may be lost.

An object of the present invention is to provide a spot welding apparatus, a spot welding method, and a workpiece to compensate for a reduction in the thickness of a pin due to a pin recess, which is inevitable in spot welding using friction stirring.

[0005]

According to the first aspect of the present invention, a pin is pressed against an object to be welded while rotating a welding tool having a pin projecting at the tip, and the object to be welded is softened by frictional heat generated by the rotation. In the spot joining method, the pin is inserted, the plastic flow is induced by stirring around the joining point with the rotating pin, and then the pin is pulled out. A spot joining method characterized by filling a pin recess formed after pulling out a pin with a filler and curing the filler to fill the pin recess.

According to a second aspect of the present invention, the filler is a resin. According to the present invention, a pin recess formed by spot joining using friction stirring is filled with a filler such as a resin, thereby preventing a local decrease in plate thickness. This compensates for the lack of strength due to local thickness reduction, and prevents a through hole from being easily formed.

According to a third aspect of the present invention, the resin is a thermosetting resin. In friction stir welding,
The temperature of the joint becomes high due to frictional heat. When the thermosetting resin is filled in the pin recess having the high temperature, the resin is cured by heat. In this way, the generated heat can be used effectively and there is also an effect of cooling the joint. Thereby, thermal deformation of the article to be joined can also be reduced.

According to a fourth aspect of the present invention, the resin is a time-curable resin that cures over time.

According to the present invention, by filling a time-curable resin, the resin can be reliably cured regardless of the temperature. Thus, even when the temperature of the pin recess changes at each joining point due to the joining conditions and the like, all the pins can be similarly cured.

According to a fifth aspect of the present invention, a pin is pressed against an object to be welded while rotating a welding tool having a pin projecting at the tip, and the pin is inserted by softening the object by frictional heat generated by rotation. After inducing a plastic flow by stirring the vicinity of the joining point with a rotating pin, by pulling out the pin, in a spot joining apparatus that spot-joins the stacked workpieces at the joining point, after the pin is pulled out A spot bonding apparatus characterized by having a filling means for filling a formed pin recess with a filler and curing the filler to fill the pin recess.

According to a sixth aspect of the present invention, a pin is pressed against an object to be welded while rotating a welding tool having a pin protruding at the tip, and the pin is inserted by softening the object by frictional heat generated by rotation. After agitating the vicinity of the joining point with a rotating pin to induce plastic flow, the pin is pulled out, so that in the joints that are lap jointed at the spot, the pin recess formed after pulling out the pin is filled. An article to be joined, characterized by being filled with an agent and cured to fill the recess.

According to the present invention, the pin recess formed by spot joining using friction stirring is filled with a filler to prevent a local decrease in plate thickness. This compensates for the lack of strength due to local thickness reduction, and prevents a through hole from being easily formed.

[0013]

FIG. 1 is a perspective view showing the configuration of a spot joining apparatus 1 according to an embodiment of the present invention. The spot welding device 1 is a device that joins two workpieces (workpieces) W1 and W2 by spots using friction stir welding, and is attached to, for example, a wrist 2 of a 6-axis vertical multi-indirect robot. Used as a spot joining gun. Such a spot joining apparatus 1 is used, for example, for joining an automobile body. Also, works W1, W
2 is, for example, an aluminum alloy.

The spot joining apparatus 1 includes a gun arm 3 attached to a wrist of a robot arm, a lifting / lowering pressing mechanism 1
0, a joining head 4, a joining tool 7, a filling means 6, and a backing material 9. The gun arm 3 is U-shaped,
It is fixed to the wrist 2 of the robot arm. The gun arm 3 is provided with a lifting / lowering mechanism 10 for raising and lowering the welding head 4 at the upper end of the gun arm 3, and the welding head 4 holds the welding tool 7.

The welding tool 7 has a substantially cylindrical shape and rotates around a central axis as a rotation axis L. The welding head 4 has a rotating motor, and the welding tool 7 is rotated around the axis L at a high speed by this motor. Drive. The tip of the joining tool 7 is flat, and a pin 8 is provided to protrude downward along the rotation axis L from the center of this flat surface. The lifting / lowering mechanism 10 has a servomotor 11, which moves the joining head 4 up and down along the axis L by the servomotor 11. The backing material 9 has a short columnar shape, and is disposed at the lower end of the gun arm 3 so as to face the pin 8 of the joining tool 7.

The filling means 6 is attached to the gun arm 3, and is disposed with the resin supply nozzle 5 at the tip facing the backing material 9.

FIG. 2 is a view showing a joining method of the present invention. With reference to FIG. 2 and FIG.
Will be described. (1) First, the two works W1 and W
The bonding apparatus 1 is positioned by a robot so that two bonding points are arranged. Next, the welding tool 7 is rotated around the rotation axis L by the motor of the welding head 4, and the welding head 4 is lowered along the axis L by the lifting and lowering mechanism 10. Then, the pin 8 at the tip of the joining tool 7 is pressed while rotating at the joining point. The rotation generates frictional heat,
As a result, the base material is softened, and the pin 8
1, W2. By inserting the pin 8 while rotating, the base material near the joining point is stirred, and plastic flow is induced. When the workpiece W is further lowered, the lower end face 7a of the joining tool 7 is pressed against the surface of the work W1 and is also stirred at the lower end face 7a, and the pin 8 exceeds the joining face of the two works W1 and W2. Thus, FIG.
As indicated by reference numeral 15 in (1), a plastic flow region is formed near the joining point. (2) In this state, after stirring with a predetermined pressing force for a predetermined time, the joining head 4 is raised by the lifting / lowering pressing machine 10. Then, the pin 8 of the joining tool 7 is pulled out, and a pin recess 16 is formed as shown in FIG. (3) Immediately after the pin 8 is pulled out, a certain amount of resin is supplied to the pin recess 16 from the resin supply nozzle 5 of the filling means 6, and the pin recess 16 is filled.

The resin to be filled is, for example, a phenol resin, an epoxy resin and a diallyl phthalate resin. In friction stir welding, when joining by friction heat,
Since the temperature at the joining point is as high as 400 ° C. or more, and the temperature of the pin recess 16 immediately after the pin 8 is pulled out is as high as about 300 ° C., the thermosetting synthetic resin is quickly cured by the residual heat. The cured resin 17 is integrated with the base material, and eliminates the local lack of strength of the pin recess 16.

The method of filling the resin 17 may be a method of dropping a liquid resin into the pin recess 16 from the nozzle 5.
A method of filling the pin recess 16 by spraying may be used.
Filling the resin 17 into the high-temperature pin recess 16 cools the joint, thereby reducing the thermal deformation of the work and improving the mechanical properties of the joint.

In the above embodiment, the resin to be filled is
Although a thermosetting synthetic resin is used, the present invention is not limited to this, and a time-hardening synthetic resin having a small temperature dependency, such as a modified silicone resin, may be used. In the case of such a resin, the pin recess 16 can be filled with a constant strength regardless of the temperature of the joining point.

[0021]

As described above, according to the present invention, the pin recess is filled with a filler such as a resin, so that a local decrease in plate thickness can be prevented. This prevents a through hole from being easily formed.

By using a thermosetting resin as the filler, the generated heat can be effectively utilized, and the joint can be cooled. Thereby, thermal deformation of the article to be joined can also be reduced.

In addition, by using a time-curable resin as the filler, the resin can be surely cured regardless of the temperature at the joining point. Thereby, even when the temperature of the pin recess differs for each joining point due to the joining conditions and the like, all of them can be similarly cured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a friction stir welding apparatus 1 according to an embodiment of the present invention.

FIG. 2 is a view showing a joining method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Friction stir welding apparatus 6 Filling means 7 Joining tool 8 Pin 16 pin recess

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takehiro Hyoe 3-1-1, Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo F-term in Kawasaki Heavy Industries, Ltd. Kobe Factory 4E067 AA05 BG00 CA04 EA07

Claims (6)

[Claims] 1. A pin is pressed against an object to be welded while rotating a welding tool having a pin protruding at a tip, and the pin is inserted by softening the object by frictional heat generated by rotation, and a joining point is formed by a rotating pin. After agitating the vicinity to induce plastic flow, the pin is pulled out, and in the spot joining method in which the stacked workpieces are spot-joined at the joining point, the pin recess formed after the pin is pulled out A spot joining method comprising filling a filler and curing the filler to fill the pin recess. 2. The spot joining method according to claim 1, wherein the filler is a resin. 3. The spot joining apparatus according to claim 2, wherein said resin is a thermosetting resin. 4. The resin according to claim 2, wherein the resin is a time-curable resin that cures over time.
The spot joining method described. 5. A pin is pressed against an object to be welded while rotating a welding tool having a pin protruding at a tip, and the pin is inserted by softening the object by frictional heat generated by rotation, and a joining point is formed by the rotating pin. After agitating the vicinity to induce plastic flow, the pin is pulled out, and in a spot joining device that joins the stacked workpieces in a spot at the joining point, the pin recess formed after the pin is pulled out What is claimed is: 1. A spot joining apparatus comprising: a filling means for filling and curing a filler to fill a pin recess. 6. A pin is pressed against an object to be welded while rotating a welding tool having a pin projecting at a tip, and the pin is inserted by softening the object by frictional heat due to rotation, and the pin is joined by a rotating pin. After the plastic flow is induced by agitating the vicinity, the pin is pulled out, and the filler is filled in the pin recess formed after pulling out the pin, and the material is hardened after the pin is pulled out in the joint that has been lap jointed at the spot. The object to be welded, wherein the recess is filled.