JP3472546B2 - Spot joining method, spot joining apparatus and workpiece - Google Patents

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 device and an article to be joined.

[0002]

2. Description of the Related Art Spot welding using friction stir is 2
A plurality of works are arranged in an overlapping manner, and a welding tool having a pin at its tip is rotated at a high speed to be lowered to press the pin to a welding point of the works. Then, the friction due to the rotation softens the pressing portion, and the pin is inserted. Further rotation causes the inserted pin to stir the vicinity of the joining point and induce plastic flow. After stirring for a predetermined time, the welding tool is raised and the pin is pulled out, and the two workpieces are welded at the welding point. In this way, lap joints can be joined at spots.

[0003]

In spot welding using friction stir, since a pin is inserted at the joining point for joining,
A pin-shaped pin recess remains in the part where the pin is pulled out. In friction stir welding, a pin induces plastic flow in the base material near the joining point and the two workpieces near the joining point are joined together, so the pin recess formed only at the joining point Does not affect the macroscopic strength of the joint,
The thickness locally decreases. Therefore, for example, when this portion is a needle-like thin object and is projected from the outside, the through hole is easily formed, and the airtightness may be lost.

An object of the present invention is to provide a spot welding apparatus, a spot welding method, and an object to be welded, which compensates for the plate thickness reduction due to the pin recess which is inevitably caused by spot welding using friction stirring.

[0005]

According to the present invention, a pin is inserted into an object to be welded by rotating a welding tool having a pin protruding at the tip thereof, and the object to be welded is softened by frictional heat generated by the rotation. Then, by stirring the vicinity of the joint with a rotating pin to induce plastic flow, and then pulling out the pin,
In the spot joining method of spot-wise joining overlapping objects to be joined, the objects to be joined are made of an aluminum alloy and are formed at 300 ° C. after the pins are pulled out.
It is characterized in that the pin recess is filled with a filler which is a thermosetting resin selected from the group consisting of a phenol resin, an epoxy resin and a diallyl phthalate resin, and is cured to fill the pin recess. This is a spot joining method.

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

The filler is a thermosetting resin. In friction stir welding, the temperature of the joining point becomes high due to frictional heat. When the thermosetting resin is filled in the pin recess that has reached this high temperature,
The resin is hardened by the heat. In this way, the generated heat can be effectively used, and at the same time, the joint portion can be cooled. As a result, thermal deformation of the objects to be joined can be reduced. This thermosetting resin is one thermosetting resin selected from the group consisting of a phenol resin, an epoxy resin and a diallyl phthalate resin. As a result, as described above, due to the residual heat after pulling out the pins during spot joining, Cure is accelerated. The temperature of this residual heat is about 300 ° C., and the residual heat is taken away by the curing of the thermosetting resin, the temperature of the aluminum alloy that is the object to be bonded is suppressed, and a decrease in strength is prevented. Further, according to the present invention, the pin is pressed against the object to be welded while rotating the welding tool having the pin protruding at the tip, the object to be welded is softened by the frictional heat due to the rotation, and the pin is inserted. After inducing plastic flow by agitating the vicinity and pulling out the pin, in a spot welding apparatus that spot-wise joins the overlapped objects to be joined, the objects to be joined are made of an aluminum alloy, and the pins are In the pin recess of about 300 ℃ formed after pulling out
It has a filling means for supplying a filler, which is a thermosetting resin selected from the group consisting of a phenol resin, an epoxy resin and a diallyl phthalate resin, from a supply nozzle to fill the filler and cure the filler to fill the pin recess. It is a characteristic spot joining device. Further, according to the present invention, the pin is pressed against the object to be welded while rotating the welding tool having the pin protruding at the tip, the object to be welded is softened by the frictional heat due to the rotation, and the pin is inserted. After stirring the vicinity to induce plastic flow and then pulling out the pin, in the welded object in which the lap joint is joined at the spot, the welded object is made of an aluminum alloy and is formed after the pin is pulled out 300 Filling the pin recess at about ℃ with a filler, which is a thermosetting resin selected from the group consisting of phenol resin, epoxy resin, and diallyl phthalate resin, and curing to fill the recess. It is a characteristic object to be joined.

[0008]

[0009]

[0010]

[0011]

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

[0013]

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

The spot joining apparatus 1 comprises a gun arm 3 attached to the wrist of a robot arm, and a lifting / lowering pressing mechanism 1.
0, the joining head 4, the joining tool 7, the filling means 6, and the 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 an elevating and lowering pressing mechanism 10 for elevating and lowering the joining head 4 on the upper side of the tip end, and the joining head 4 holds the joining tool 7.

The welding tool 7 has a substantially cylindrical shape and rotates about the central axis as the rotation axis L, and the welding head 4 has a rotation motor, which rotates the welding tool 7 around the axis L at high speed. To drive. The tip of the welding tool 7 is flat, and a pin 8 is provided so as to project downward along the rotation axis L from the center of this flat surface. The up-and-down pressing mechanism 10 has a servo motor 11, and the servo motor 11 moves up and down the bonding head 4 along the axis L. The backing material 9 has a short cylindrical shape, and is arranged at the lower end of the gun arm 3 so as to face the pin 8 of the welding tool 7.

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

FIG. 2 is a diagram showing the joining method of the present invention. With reference to FIGS. 2 and 1, the spot joining apparatus 1
The joining method by will be described. (1) First, on the upper surface of the backing plate 9, two works W1 and W
The joining device 1 is positioned by the robot so that the two joining points are arranged. Next, the motor of the welding head 4 rotates the welding tool 7 around the rotation axis L, and the lifting / lowering pressing mechanism 10 lowers the welding head 4 along the axis L. Then, the pin 8 at the tip of the welding tool 7 is pressed against the welding point while rotating. Friction heat is generated by rotation,
This softens the base material, and the pin 8 has two workpieces W
1, W2. By inserting the pin 8 while rotating, the base material in the vicinity of the joining point is agitated and plastic flow is induced. When it further descends, the lower end surface 7a of the welding tool 7 is pressed against the surface of the work W1 and is also agitated at this lower end surface 7a, and the pin 8 exceeds the joint surface of the two works W1 and W2. In this way, FIG.
As indicated by reference numeral 15 in (1), a plastic flow region is formed near the junction. (2) In this state, after stirring with a predetermined pressing force for a predetermined time, the raising / lowering press 10 raises the bonding head 4. Then, the pin 8 of the welding tool 7 is pulled out, and the pin recess 16 is formed as shown in FIG. (3) Immediately after the pin 8 is pulled out, a fixed amount of resin is supplied from the resin supply nozzle 5 of the filling means 6 to the pin recess 16 to fill the pin recess 16.

The resin to be filled is, for example, phenol resin, epoxy resin or diallyl phthalate resin. In friction stir welding, when joining by friction heat,
Since the temperature of the joining point becomes a high temperature of 400 ° C. or higher, and the temperature of the pin recess 16 immediately after pulling out the pin 8 is also a high temperature of about 300 ° C., the residual heat quickly cures the thermosetting synthetic resin. The hardened resin 17 is integrated with the base material to eliminate 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 injecting to fill the pin recess 16 may be used.
Further, by filling the high-temperature pin recess 16 with the resin 17, the joint portion is cooled, which also reduces the thermal deformation of the work and has the effect of improving the mechanical properties of the joint.

[0020]

[0021]

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

Further, by using a thermosetting resin as the filler, it is possible to effectively utilize the heat generated and also to cool the joint portion. As a result, thermal deformation of the objects to be joined can be reduced.

[0023]

[Brief description of 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 diagram showing a joining method of the present invention.

[Explanation of symbols]

1 Friction stir welding equipment 6 filling means 7 joining tool 8 pin 16 pin recess

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-230372 (JP, A) JP-A-2000-176658 (JP, A) JP-A-2000-42781 (JP, A) JP-A-11-156561 ( JP, A) JP 53-129225 (JP, A) C.I. Schilling et al. , A PRELIMINARY I NVESTIGATION ON TH E STATIC PROPERTIE S OF FRICTION STIR SPOT WELDS, Second International Sym posium on Friction Stir Welding, the UK, T he Welding Institu te, 6 May 26, 2000, Qualit y Hotel 11, Gothenb urg, Sweden Presented at the 2nd FSW International Symposium held at (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23K 20/12

Claims (3)

(57) [Claims] 1. A welding tool having a pin protruding at its tip is pressed against an object to be welded while being rotated, the object to be welded is softened by frictional heat due to rotation, and the pin is inserted. In the spot welding method, in which the overlapped objects are spot-wise joined at the joining points by stirring around and inducing plastic flow and then pulling out the pins, the objects to be joined are made of aluminum alloy, The pin recess formed at about 300 ° C. after being drawn out is filled with a filler which is one thermosetting resin selected from the group consisting of phenol resin, epoxy resin and diallyl phthalate resin, and the pin is hardened. A spot joining method characterized by filling a recess. 2. A welding tool having a pin protruding at its tip is pressed against an object to be welded while being rotated, the object to be welded is softened by frictional heat generated by the rotation, and the pin is inserted. In a spot welding apparatus that spot-joins stacked objects to be joined by pulling out the pins after agitating the vicinity to induce plastic flow, the objects to be joined are made of aluminum alloy, Filling the pin concavity formed at about 300 ° C after drawing out the filler, which is one thermosetting resin selected from the group consisting of phenol resin, epoxy resin and diallyl phthalate resin, from the supply nozzle. Then, the spot joining apparatus is characterized by having a filling means for filling and curing the pin recess. 3. A welding tool having a pin projecting at the tip is rotated to press the pin against an object to be welded, the object to be welded is softened by frictional heat generated by the rotation, and the pin is inserted. After stirring the vicinity and inducing plastic flow, the pin is pulled out, and in the welded object that is lap joint joined at the spot, the welded object is made of an aluminum alloy and is formed after the pin is pulled out. Filling the pin recess at about ℃ with a filler, which is a thermosetting resin selected from the group consisting of phenol resin, epoxy resin, and diallyl phthalate resin, and curing to fill the recess. Characteristic to be joined.