JP2002120076A - Spot joining apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spot joining apparatus utilizing friction stir with which the deterioration of joined quality can be prevented. SOLUTION: The spot joining apparatus 1 is provided with a joining tool 5, a pressurizing means 8 and a receiving part 11. The pressurizing means 8 is provided with a spring member 16 and an annular pushing member 15. When a pressure imparting device 7 is moved down while rotating the joining tool with a motor 6 for rotation, firstly, the pushing member 15 in the pressurizing means 8 is abutted on two sheets of works W1, W2 disposed by piling up on the receiving member 11, and the pushing force is acted near the joining point. In this way, the works W1, W2 are closely stuck to eliminate any gap. Further, when the joining tool 5 is moved down while rotating, a pin 10 at the tip of the tool is inserted into the work while rotating, and a base metal is stirred. When the joining tool 5 is pulled up, the works are joined at the spot point and the pressure imparted by the pressurizing means 8 is released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a spot welding apparatus and a spot welding method for spot welding workpieces by friction stir welding.

[0002]

2. Description of the Related Art Spot welding using friction stirrer has two
A plurality of workpieces are placed one on top of the other, the joining tool having a pin at the tip is lowered while rotating at a high speed, and the tip of the joining tool is pressed against the joining point of the workpiece. 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 joint is agitated by the inserted pin, causing plastic flow. After the stirring for a predetermined time, when the joining tool is raised, the two workpieces are joined at the joining point,
Spot-joined.

[0003]

SUMMARY OF THE INVENTION In spot welding using friction stirring, since spot welding is performed using a lap joint,
The management of the gap between the upper and lower plates is extremely important for the joining quality. In other words, it is important to join two works in a state where they are overlapped with no gap at the joining point in order to maintain the joining quality. However, depending on the shape of the work, the two works are surely brought into close contact with each other. In some cases, it is difficult to perform such a process, which causes a problem that the bonding quality is deteriorated.

[0004] An object of the present invention is to provide a spot welding apparatus utilizing friction stirring, which can prevent a decrease in welding quality.

[0005]

According to the present invention, the tip is pressed against the workpiece while rotating the welding tool, and the workpiece is softened by frictional heat generated by the rotation of the welding tool.
What is claimed is: 1. A spot welding apparatus for agitating and superimposing an object to be spot-joined at a joining point in a spot joining apparatus, comprising: .

According to the present invention, since the pressing means for pressing the vicinity of the joining point of the objects is provided, even if there is a gap between the two objects, the pressing means presses the object. This eliminates the gap at the joining point, thereby reliably preventing the joining quality from deteriorating.

[0007] The pressing means of the present invention according to claim 2 is characterized in that:
In conjunction with the movement of the welding tool in the rotation axis direction, the welding tool operates so as to press the workpiece from immediately before to immediately after pressing the workpiece.

According to the present invention, the pressing means is interlocked with the welding tool, and is pressed immediately before the welding tool is lowered and pressed against the workpiece, and is pressed until immediately after the welding tool is lifted and released from the pressing. Therefore, the gap at the time of the joining operation can be eliminated, and the continuous spot joining operation can be performed.

The present invention according to claim 3 is characterized in that it has a receiving portion for receiving the pressing force of the pressing tool and the tip of the joining tool. According to the present invention, since the receiving portion receives the pressing force, the pressing force can be reliably applied.

According to a fourth aspect of the present invention, the pressing means comprises:
It has a pressing member that abuts on the workpiece to apply a pressing force. The pressing member has high thermal conductivity, and releases heat from the abutting workpiece.

[0011] In friction stir welding, the object to be welded becomes extremely hot due to frictional heat, which causes a problem that the strength of the welded portion and its peripheral region is reduced. On the other hand, in the present invention, since the pressing member pressed against the vicinity of the junction has high thermal conductivity, the heat generated at the junction can be released through the pressing member. Accordingly, the high heat is applied only to the vicinity of the joining point, and the other area is prevented from becoming high temperature, and the area of the area where the strength is reduced in the article to be joined can be minimized.

According to a fifth aspect of the present invention, the tip is pressed against the workpiece while rotating the welding tool, and the workpiece is softened and agitated by frictional heat generated by the rotation of the welding tool. In the spot joining method that joins the spots at the joining points, when the joining tool is pressed by the joining tool,
This is a spot joining method characterized by pressing the vicinity of a joining point of an object to be joined.

According to the present invention, even if there is a gap between the two workpieces, the gap at the junction is eliminated by pressing the vicinity of the junction at the time of joining, thereby improving the joining quality. Is reliably prevented from decreasing.

[0014]

FIG. 1 is a view showing the structure of a spot joining apparatus 1 according to an embodiment of the present invention. The spot welding apparatus 1 is mounted on, for example, a wrist 2 of a 6-axis vertical multi-indirect robot, is used as a spot gun, and spots two work pieces (workpieces) W1 and W2 arranged one on top of another at a joining point. Bonding. The works W1 and W2 are
An example is an aluminum alloy plate.

The spot joining device 1 is composed of a robot wrist 2
, A bracket 4 attached to the frame 3, a joining tool 6 rotatably supported by the bracket 4, and attached to the bracket 4,
A rotating motor 6 for rotating and driving the joining tool 5, a pressurizing device 7 for driving the bracket 4 to move up and down with respect to the frame 3 to apply a pressing force to the joining tool 5,
Pressing means 8 for pressing near the joining point.

The joining tool 5 is substantially cylindrical and has an axis L
Is driven to rotate by the rotation motor 6 with the rotation axis as a rotation axis. The pin 10 projects downward along the rotation axis L from the center of the flat surface at the tip of the welding tool. The pressure applying device 7 has, for example, a servomotor, and moves the bracket 4 linearly in the direction of the rotation axis L of the joining tool 6 to apply a pressing force.

The pressing means 8 has a pressing member 15 which comes into contact with the work W1 to apply a pressing force, and a spring member 16 which applies a spring force to the pressing member. Frame 4
Is bent in an L-shape, and a receiving portion 11 is provided at a distal end thereof, which faces below the joining tool 5 and receives the pressing force of the joining tool 5 and the pressing member 15.

FIG. 2 shows the pressing means 8 of the spot joining apparatus 1.
It is a perspective view which shows the vicinity. The pressing means 8 includes the bracket 4
A base 19 fixed below the base 19, an upper frame 17 fixed below the base 19 and accommodating the spring member 16, and an upper frame 17 movably in the rotation axis L direction of the joining tool 5.
And a lower pressing member 15 fixed to a lower end of the lower frame 18. The spring member 16 is a compression coil spring and is housed in the upper frame 17 around the joining tool 5.
The lower frame 18 is connected to the upper frame 17 so as to be movable up and down, and when the lower frame 18 rises, the spring member 16 is compressed.

The pressing member 15 is an annular member centered on the rotation axis L of the welding tool 5, has an inner diameter slightly larger than the diameter of the welding tool 5, and presses the vicinity of the welding point during welding. When the lower frame 18 is at the lower limit position, the lower end surface of the pressing member 15 is disposed below the lowermost end of the joining tool 5. The receiving portion 11 arranged to face the pressing member 15 is a columnar shape having a diameter equal to or larger than the pressing member 15, and at the time of joining,
The upper surface of the receiving portion 11 and the lower surface of the pressing member 15
The work W1 and the work W2 are sandwiched and adhered to each other around the joining point.

At least the pressing member 15 of the pressing means 8 is made of a material having good heat conductivity, for example, copper or the like.
2 can be prevented from deteriorating the corrosion resistance of the works W1 and W2.

FIG. 3 is a diagram showing a joining method of the spot joining apparatus 1. The joining method will be described with reference to FIG. (1) First, two works W1 and W2 that are arranged in an overlapping manner
The spot welding apparatus 1 is moved by a robot until the receiving portion 11 is positioned below a predetermined joining point, and the joining tool 5 is rotated by the rotation motor 6. (2) The joining device 1 is lifted to bring the receiving portion 11 into contact below the joining point, and the pressing device 7
Is lowered. Then, the joining tool 5 and the pressing means 8 attached to the bracket 4 descend, and first, the pressing member 15 of the pressing means 8 comes into contact with the workpiece W1. When the bracket 4 is further lowered, the spring member 16 of the pressing means 8 is compressed, and a pressing force acts on the works W1 and W2.
The vicinity of the junction is pressed. Accordingly, even when a gap is formed between the work W1 and the work W2 at the joining point, the work W1 and the work W2 come into close contact with each other. (3) When the bracket 4 is further lowered, the pressing force is further applied by the spring force, and the joining tool 5 is lowered, and the pin 10 at the tool tip is pressed against the joining point. When the pin 10 rotating at a high speed is pressed against the joining point, frictional heat is generated, the works W1 and W2 are softened, and the pin 10 is inserted. When the pin 10 is at the junction, the workpiece W1,
When inserted into W2 beyond the joint surface and rotated, the base material near the joint is agitated to cause plastic flow.
At this time, frictional heat is generated, but the annular pressing member 15 is in contact with the workpiece W1 so as to surround the joining point, and as described above, the pressing member 15 is made of a material having good heat conductivity. Therefore, heat that is transmitted from the joining point to the periphery of the work and spreads is released from the pressing member 15. As a result, high heat is generated in the vicinity of the joining point, and high heat is prevented from being transmitted to other areas of the work. (4) After stirring for a predetermined time, the bracket 4 is raised by the pressing and applying device 7 of the spot joining device 1. Thereby, the joining tool 5 rises while rotating, and the pin 10 is pulled out from the joining point. Also at this time, the vicinity of the joining point is continuously pressed by the pressing means 8, and the two workpieces W1,
The close contact state of W2 is maintained. That is, the two works W1 and W2 are in close contact with each other until the plastic flow portion is cooled and hardened. Also, the pressing member 15 of the pressing means 8
, The cooling effect is also improved. (5) By further raising the bracket 4,
The pressing member 15 of the pressing means 8 also separates from the work W1, and the pressing force is released. Thus, the work W
1 and W2 are spot-like joined at the joining point. afterwards,
The spot joining apparatus 1 is moved to the next joining point, and the operation from (1) described above is repeated.

In this way, spot joining can be performed continuously. Further, at this time, by using the pressing means 8 using the spring member 16, in synchronization with the elevating operation of the joining tool 5, the pressing member 15 presses the vicinity of the joining point immediately before the joining tool 5 comes into contact with the workpiece W1. Immediately after the pin 10 of the joining tool 5 is pulled out, the pressing force can be released.

In the above-described embodiment, the pressing member 15
Is made of a material having high thermal conductivity, but as another embodiment of the present invention, the pressing member 15 is made hollow, and a pair of cooling pipelines 20 and 21 are connected as shown by a virtual line in FIG. The cooling water may be configured to pass from one pipe 20 to the other pipe 21 through the pressing member 15. With this configuration, the pressing member 1
When the workpiece 5 is brought into contact with the work, the work to be heated can be forcibly cooled, and can be cooled more efficiently.

FIG. 4 is a perspective view showing the configuration of a spot joining apparatus 30 according to another embodiment of the present invention. In the spot joining device 30 of the present embodiment, a pair of pressing members 32,
33, and the pressing member 3
2 and 33 have a rectangular parallelepiped receiving portion 34. Other configurations are the same as those of the spot bonding apparatus 1 described above, and therefore, are denoted by the same reference numerals and description thereof will be omitted.

The pressing members 32 and 33 of the pressing means 31 have a rectangular parallelepiped shape, have substantially the same length as the outer diameter of the joining tool 5, and are disposed on both left and right sides of the joining tool 5. Then, the pressing members 32 and 33 individually apply the pressing force by the spring members 35 and 36, respectively. That is, when the pressing force applying device 7 lowers the bracket 4, the pressing members 32 and 33 are individually pressed against the work. At this time, the receiving member 34 has a rectangular parallelepiped shape extending left and right opposite to the two pressing members 32 and 33 as shown in the figure, and receives the pressing force from the pressing members 32 and 33 and the joining tool 5.

As described above, the pressing means 31 of the present embodiment
Is the annular pressing member 15 of the spot device 1 described above.
Unlike this, since the pressing is performed on both sides of the joining tool 5, the pressing area can be reduced. Therefore, as shown in FIG. 4, even when the joining area is narrow, for example, when joining the bent portion of the bent work W4 to the plate-like work W3, the pressing force is reliably applied to the joining point. Nearby work W3, W4
Can be adhered to each other.

Further, for example, even if the work becomes a step near the joining point and the thickness is different, the pressing member 3
Since the pressing members 2 and 33 individually expand and contract to apply the pressing force, it is possible to cope with such a step.

Further, by forming the pressing members 32 and 33 of a metal having good thermal conductivity, the work can be prevented from being heated. Further, as described above, by configuring the cooling water to pass through the pressing members 32 and 33, the cooling can be performed more efficiently.

In each of the embodiments described above, the pressing force applied by the pressing means is a pressing force by a spring. However, the present invention is not limited to this. For example, a pressing member may be formed by using a hydraulic cylinder, a pneumatic cylinder, or a servomotor. May be separately raised and lowered in the direction of the rotation axis L and pressed separately from the joining tool. In this case, the raising and lowering operation of the pressing member is controlled so as to interlock with the raising and lowering operation of the joining tool,
Before the joining tool descends, the pressing member is lowered to apply the pressing force, and after the joining tool is pulled up, the pressing member is controlled to be pulled up.

[0030]

According to the present invention, since the pressing means for pressing the vicinity of the joining point of the objects is provided, even if there is a gap between the two objects, the pressing means is used. The pressing eliminates the gap at the joining point, thereby reliably preventing the joining quality from deteriorating.

Further, according to the present invention, a continuous spot joining operation can be performed by operating the pressing means in conjunction with the joining tool.

Further, according to the present invention, since the pressing member pressed to the vicinity of the junction has high thermal conductivity,
The heat generated at the joint can be released through the pressing member, so that the high heat is limited only to the vicinity of the joint and the other regions are prevented from becoming high in temperature.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a spot joining apparatus 1 according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration near a pressing means 8 of the spot joining apparatus 1;

FIG. 3 is a view showing a spot joining method of the present invention.

FIG. 4 shows a spot joining apparatus 30 according to another embodiment of the present invention.
FIG.

[Explanation of symbols]

 1,30 Spot joining device 5 Joining tool 8,31 Pressing means 11,34 Receiving part 15,32,33 Pressing member

Claims (5)

[Claims] 1. A tip is pressed against a workpiece while rotating a welding tool, and the workpiece is softened and agitated by frictional heat generated by the rotation of the welding tool. What is claimed is: 1. A spot joining apparatus for joining, comprising: pressing means for pressing near a joining point of an object to be joined at the time of joining. 2. The method according to claim 1, wherein the pressing means operates in conjunction with the movement of the welding tool in the rotation axis direction so as to press the workpiece from immediately before to immediately after the tip of the welding tool presses the workpiece. The spot joining apparatus according to claim 1, wherein 3. The spot welding apparatus according to claim 1, further comprising a receiving portion which receives a pressing force of a pressing tool and a tip of the welding tool. 4. The pressing means has a pressing member which applies a pressing force by contacting the object to be bonded, and the pressing member has high thermal conductivity and releases heat of the object to be contacted. The spot joining apparatus according to claim 1, wherein: 5. The welding tool is rotated while the tip is pressed against the workpiece, and the workpiece is softened and agitated by frictional heat generated by the rotation of the welding tool. A spot joining method for joining, wherein the joining tool presses the vicinity of the joining point of the article when the article is pressed by the joining tool.