JPH0890266A - Welding method using high density energy beam, and its device - Google Patents

Abstract

PURPOSE: To improve the welding precision by constantly matching the positional relationship between parts to be welded when temporarily spot-welded works at prescribed intervals are finally and continuously welded, and suppressing the rise of the joined parts during the temporary welding. CONSTITUTION: The actual position of a temporarily welded part X of a work W1 (W2) which is temporarily welded using the laser beam by a temporary welding station 1 is detected based on the data from a camera 18 and an analyzing instrument 19, and the final welding line is set as the part to be permanently welded based on the locus obtained by successively connecting these temporarily welded parts X. A control unit 24 to control so that a welding robot 22 may scan the laser beam irradiated from a torch 20 along this final welding line through a working device 23 is provided on a final welding station 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding method and apparatus for temporarily welding workpieces to be joined and then performing final welding.

[0002]

2. Description of the Related Art In the case of joining work pieces in a manufacturing process of an automobile or the like, first, as disclosed in, for example, Japanese Patent Application Laid-Open No. 1-91988, in order to prevent the work pieces from being displaced due to thermal deformation during welding. After performing resistance welding on the joint of the work piece using a pressure electrode and spot-temporarily welding at a predetermined interval, the provisionally-welded joint is irradiated with a high-density energy beam such as a laser beam or an electron beam. And continuous main welding is performed.

In the case of the main welding, the main welding site where the high-density energy beam is irradiated is determined from the viewpoint of the shape of the joint, the obtained joint strength, and the like, and is temporarily welded, for example, so-called lap welding. It is customary to weld the tentatively welded portions in the joined portion in order, or continuously weld the portions that are separated from the tentatively welded portion by a predetermined distance, such as edge welding and fillet welding. And in any case,
If the positional relationship between the main welded portion and the temporary welded portion is not accurately matched, the above-mentioned beam will not be properly irradiated to the joint portion, and as a result, the workpiece will not be joined or the predetermined joining strength cannot be obtained. The problem arises.

Therefore, conventionally, all the temporary welding parts to be spot-welded by the temporary welding device are stored in advance in the main welding device, and in the case of, for example, lap welding, these stored temporary welding parts are sequentially stored. A locus obtained by tying is set as a main welding site, and the beam is irradiated along the locus during main welding.

According to this, since the main welding site is set in advance with the temporary welding site as a reference, the positional relationship between the two sites is well matched, and the problem of poor joint is solved.

[0006]

However, the workpiece is thermally deformed by being continuously irradiated with the above-mentioned beam during the main welding, and as a result, the position of the temporary welding portion is deviated and the preset main welding portion is There is a problem that the positional relationship of is not matched. Further, in the case where the temporary welding station and the main welding station are separately provided, an error is likely to occur in the positioning when the temporarily welded work is carried into the main welding station, and the temporary welding site of the installed work is There is a problem in that the actual main-welded portion does not match the preset main-welded portion due to the displacement of the position.

Further, as disclosed in the above publication, when the temporary welding is performed by resistance welding using a pressure electrode, the temporary welding portion is pressed, and the surrounding portion of the portion is lifted by its reaction. As a result, at the time of main welding, the joints do not adhere to each other and a joint failure occurs.

The present invention addresses the above-mentioned problems in the case where the joints of the workpiece are spot-temporarily welded at a predetermined interval and then continuously main-welded by using a high-density energy beam. The purpose of the present invention is to improve the welding accuracy by always matching the positional relationship between the temporary welding portion and the temporary welding portion and suppressing the floating of the joint portion during the temporary welding.

[0009]

In order to solve the above-mentioned problems, the present invention is characterized by being configured as follows.

That is, the invention according to claim 1 of the present application (hereinafter referred to as the "first invention") is a welding in which the joint portion of the workpiece is spot-temporarily welded at predetermined intervals and then continuously main-welded. In the method, after performing the temporary welding using a high-density energy beam, the temporary welding portion is detected by detecting a physical difference between the temporary welding portion and another portion in the temporarily welded joint portion. The main welding line is set based on the temporary welding line obtained by identifying and adjoining adjacent ones of the identified temporary welding parts in order, and the high-density energy beam is set along the set main welding line. It is characterized in that the main welding is performed by irradiating.

Further, in the invention described in claim 2 of the present application (hereinafter referred to as "second invention"), in the first invention, the physical difference detected when identifying the temporary welding portion is an optical difference. Is characterized in that.

The invention according to claim 3 of the present application (hereinafter referred to as "third invention") is the same as the first invention described above.
The interval at which the corner portion of the joint is temporarily welded is smaller than the interval at which the straight portion is temporarily welded.

On the other hand, the invention according to claim 4 of the present application (hereinafter referred to as the "fourth invention") is welding in which the joint portion of the work is temporarily welded in spots at predetermined intervals and then continuously main welded. A device, which is a temporary welding device for performing the above-mentioned temporary welding by irradiating a joint part of a work with a high-density energy beam, and a temporary welding part and another part in the joint part temporarily welded by the temporary welding device. Detecting means for detecting a physical difference, identifying means for identifying the temporary welding portion based on the physical difference detected by the detecting means, and adjacent ones of the temporary welding portions identified by the identifying means are sequentially arranged. Temporary welding line setting means for setting the temporary welding line by tying, main welding line setting means for setting the main welding line based on the temporary welding line set by the temporary welding line setting means, and the main welding line setting means By irradiating the high density energy beam along the weld line to be set, characterized in that the main welding device for performing the main welding is provided.

The invention according to claim 5 of the present application (hereinafter referred to as the "fifth invention") is characterized in that, in the fourth invention, the physical difference detected by the detecting means is an optical difference. And

The invention according to claim 6 of the present application (hereinafter referred to as "sixth invention") is the same as the fourth invention.
The interval at which the temporary welding device temporarily welds the corner portion of the joint is smaller than the interval at which the straight portion is temporarily welded.

[0016]

According to the above construction, the following operation can be obtained.

That is, in any of the welding methods of the first invention, the second invention, and the third invention, since the temporary welding of the work is performed by using the high-density energy beam, the temporary welding portion is not pressed, Lifting of the joint portion during temporary welding is suppressed.

When the main welding is performed by irradiating the high-density energy beam along the main welding line, the main welding line is a temporary welding line obtained by sequentially connecting adjacent ones of the temporary welding portions. The temporary welding site is a temporary welding site that is identified by detecting a physical difference between the temporary welding site and the other site in the temporarily welded joint. The position of the temporary welding part is set as a reference, and the main welding line is set with this temporary welding line as a reference.As a result, the main welding is always performed at the correct position with respect to the temporary welding part. Become.

In this case, if the main welding line is set on the basis of the temporary welding line so as to match the temporary welding line,
Lap welding can be performed, and edge welding or fillet welding can be performed when set at a predetermined distance from the temporary welding line.

Further, since the temporary welded portion is identified by detecting the physical difference between the welded portion and other portions, the change in the lightness or hue of the work surface due to melting or oxidation during the temporary welding, or the change in shape, etc. Based on the above, the temporary welded portion can be reliably identified.

In particular, in the second aspect of the invention, since the optical difference is detected as the physical difference, the joint is melted and oxidized as a result of being irradiated with the high-density energy beam, and is darkened as compared with other portions. When the lightness or hue changes, it is possible to reliably identify the temporary welded portion.

On the other hand, in the third aspect of the invention, since the interval of the temporary welding at the corner portion of the joint is made smaller than that at the straight portion, the corner portion having poor flatness is spot welded densely and the problem of floating is suppressed. In addition, the main welding line can be set smoothly along the corners.

Further, in any of the welding devices of the fourth, fifth and sixth inventions, since the temporary welding device performs temporary welding using the high-density energy beam, the temporary welding portion may be pressed. Therefore, floating of the joint portion during temporary welding is suppressed.

When the main welding apparatus performs main welding by irradiating the main welding line with a high-density energy beam, the main welding lines are adjacent to each other at the temporary welding portions identified by the identifying means. The temporary welding part set by the main welding line setting means on the basis of the temporary welding line set by the temporary welding line setting means and the temporary welding portion identified by the identifying means is detected by the detecting means. Since it is a temporary welding site that is identified based on the physical difference with other parts in the welded joint, the temporary welding line is set based on the position of the actual temporary welding site, and the main welding line is The temporary welding line is set as a reference, and as a result, the main welding is always performed at the correct position with respect to the temporary welding site.

In this case, if the main welding line setting means sets the main welding line on the basis of the temporary welding line so as to match the temporary welding line, lap welding can be carried out, and the temporary welding line can be changed. If they are set apart by a predetermined distance, edge welding or fillet welding can be performed.

Further, since the identifying means identifies the temporary welded portion based on the physical difference detected by the detecting means, the lightness or hue of the work surface is changed by melting or oxidation during the temporary welding, or the shape is changed. This ensures that the temporary welded portion is identified.

In particular, since the detecting means in the fifth aspect of the invention detects an optical difference as the physical difference, it is melted and oxidized as a result of irradiation of the high-density energy beam at the joint, and compared with other parts. When the lightness or the hue such as darkening has changed, the identifying means can reliably identify the temporary welded portion.

On the other hand, in the temporary welding device according to the sixth aspect of the present invention, the interval of the temporary welding at the corner portion of the joint is made smaller than that at the straight portion, so that the corner portion having poor flatness is densely spot-welded to cause the floating. While the problem is suppressed, the main welding line setting means can set the main welding line smoothly along the corner portion.

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, a case will be described in which a side frame inner assembly and a side frame outer of an automobile are joined by a flange formed around these door mounting portions.

First, as shown in FIG. 1, the side frame inner assembly W1 and the side frame outer W2 are carried into the temporary welding station 1, and both works W1, W1 are carried.
After the annular flanges F1, F1 and F2, F2 respectively formed over the periphery of the two door mounting portions are overlapped, the front and rear of the works W1, W2 are gripped and set by the two clamps 2, 2.

Next, a plurality of clamp jigs 3 ... 3 having a built-in laser torch are attached to the flanges F1 and F2. As shown in an enlarged view in FIG. 2, the clamp jig 3 has a drive block 6 and a fixed block 7 which are opened and closed by a cylinder 4 around a hinge 5, and both blocks 6 and 6.
The flanges F1 and F2 are gripped between 7 and the fixing block 7 is provided with a through hole 8 in which a condenser lens 9 is provided. Then, after the laser oscillated by the laser oscillator 10 is introduced into the through hole 8 through the transmission optical system 11 made of an optical fiber, as shown by the arrow in the figure, it is condensed by the lens 9 and grasped. Flange F
1, F2 is irradiated. As a result, the flanges F1, F2 are spot-temporarily welded at the portion where the clamp jig 3 is attached, and in that case, the temporary welding portion X ′ irradiated with the laser beam is the work W1, W2. Due to the melting and oxidation of the material, the blackening occurs compared to the other parts of the flanges F1 and F2.

Then, as shown in FIG. 1, the flange F
At the corners of F1 and F2, the adjacent temporary welding parts X ',
The clamp jigs 3 ... 3 are attached to the flanges F1 and F2 so that the intervals of X ′ are smaller and denser than the straight portions, and temporary welding is performed. It should be noted that the respective parts to which the clamp jigs 3 ... At this time are attached are previously stored in a memory in a controller (not shown), and during temporary welding, spot welding is performed at these stored parts.

Next, after releasing the clamps 2 and 2, as shown in FIG. 3, the temporarily welded works W1 and W2 are transferred to the main welding station 13 by the transfer device 12.

At the main welding station 13, the temporary welding parts X '... Of the loaded works W1 and W2.
Lap welding is performed by connecting adjacent X's of X'and X'in order and welding. And the station 1
As shown in FIG.
Two work clamps 14 and 14 for gripping and setting the front and rear of the clamp, and gripping of these clamps 14 and 14,
A work clamp actuating device 15 for releasing and a plurality of flange clamps 1 for gripping and fixing predetermined portions of the flanges F1, F2 of the set works W1, W2.
16 and a flange clamp actuating device 17 for gripping and releasing these flange clamps 16 ... 16 and a CCD camera 18 for capturing the surface images of the works W1 and W2.
And an image analysis device 19 for optically analyzing image data from the camera 18 based on hue and brightness, a welding robot 22 having a laser torch 20 provided on an arm 21, and a robot operating device for performing a welding operation of the robot 22. 23, and receives the workpiece carry-in signal notifying the end of the carry-in from the carrying device 12 and the analysis signal from the image analyzing device 19 to the clamp operating devices 15 and 17 and the robot operating device 23, respectively. A control unit 24 that outputs a control signal is provided.

Here, as shown in FIG. 4, the laser torch 20 of the welding robot 22 is provided with a condenser lens 20b in the through hole 20a, and the laser oscillated by the laser oscillator 25 is transmitted by an optical fiber. After being introduced into the through hole 20a through the optical system 26, as shown by the arrow in the figure, the light is condensed by the lens 20b, emitted from the emission port 20c, and irradiated to the flanges F1 and F2 located below. It is configured to be. The control unit 24 controls the welding position, welding speed and the like of the torch 20 and the arm 21 via the robot operating device 23 to continuously weld the flanges F1 and F2. The laser oscillator 25 includes
A control board 27 for adjusting laser output, waveform, etc. is provided.

Next, the control unit 24 carries the workpieces W1 and W loaded into the main welding station 13.
The main welding control for No. 2 will be described with reference to the flowchart shown in FIG.

First, when a work loading signal is input from the transport device 12 in step S1, the control unit 24 outputs a gripping signal to the work clamp actuating device 15 in step S2, so that the loaded works W1 and W2 are detected. The front and rear are clamped by the clamps 14, 14 for setting.

Next, the control unit 24 corrects the welding start portion before the welding robot 22 performs the main welding of the works W1 and W2. That is, the control unit 24 stores in advance the position coordinates (xn, yn, zn) of all the temporary welding spots to be spot-welded in the temporary welding station 1 (hereinafter, this position coordinate will be referred to as " Memory coordinates ”.),
The control unit 24 determines a predetermined one of these as a welding start site, and connects a temporary welding site that is adjacent to the welding start site in that order and sets a trajectory that returns to the welding start site again as a temporary welding line. Further, the control unit 24 sets the main welding line based on the set temporary welding line. However, in the main welding station 13, since the lap welding is performed as described above, the control unit 24 performs the main welding. The line is set to coincide with the temporary welding line, and the welding robot 22 is controlled so that the laser beam emitted from the laser torch 20 scans along the main welding line equal to the temporary welding line.
Further, the control unit 24 includes the image analysis device 19
The workpieces W1 and W2 set in the main welding station 13 based on the image analysis signal input from
The temporary welding parts X ′ ... X ′ are identified and their position coordinates (xn ′, yn ′, zn ′) are calculated (hereinafter, these position coordinates are referred to as “actual coordinates”). This temporary welding portion X'is identified by the blackened temporary welding portion X'and the flanges F1, F.
It is carried out by detecting an optical difference such as hue and lightness with respect to the other parts in 2. Then, the control unit 24 sets the memory coordinates (x0, y0, z0) and the actual coordinates (x0 ', y) for the welding start portion.
0 ', z0') and the deviation (a0, b0, c
0) is calculated in step S3.

As a result, in step S4, the deviation (a
0, b0, c0) are all determined to be 0, it is determined that the stored welding start portion and the actual welding start portion are at the same position, and the memory coordinates (x0, y) of the welding start portion are set.
0, z0) is not corrected and the process proceeds to step S5, where a gripping signal is output to the flange clamp actuating device 17 to grip and fix the flanges F1 and F2 by the clamps 16 ... 16 while the deviation (a0 , B0, c0) is not 0, it is determined that the memorized position of the welding start portion is different from the actual position of the welding start portion, and the process proceeds to step S6 and all deviations ( a
After correcting the memory coordinates (x0, y0, z0) of the welding start portion so that 0, b0, c0) becomes 0, the process proceeds to step S5, and the flanges F1, F2 are fixed. In that case, the memory coordinates (x0, y0,
With the change of z0), the temporary welding line and the main welding line will be corrected between the welding start portion and the next adjacent temporary welding portion.

Thereafter, the control unit 24
In step S7, a welding start signal is output to the robot actuator 23. As a result, the torch 20 and the arm 21 of the robot 22 are actuated, the laser beam is applied to the welding start portion whose memory coordinates are corrected so as to match the actual coordinates as described above, and the welding start portion is then fed with the laser beam. The laser beam is scanned along the welding line to start the main welding.

Then, during the main welding, the control unit 24 controls the memory coordinates (x
n, yn, zn) and real coordinates (xn ', yn', zn ')
Continuing to make a comparison, the memory coordinates (xn, yn, zn) are corrected and the temporary welding line and the main welding line are corrected based on the result, and the main welding is performed along the corrected main welding line. The robot actuator 23 is controlled so that

That is, after starting the main welding, the control unit 24 proceeds to step S8, and the memory coordinates (xn, yn, zn) for the next temporary welding portion (n = 1) adjacent to the welding start portion. And its real coordinates (x
n ', yn', zn ') and the deviation (an, b
n, cn) is calculated. If it is determined in step S9 that all the deviations (an, bn, cn) are 0, it is determined that the memorized next temporary welding site and the actual temporary welding site are at the same position, and the next temporary welding process is performed. Memory coordinates of part (x
n, yn, zn) is not corrected and the process proceeds to step S10 to continue welding along the currently set main welding line, while at least one of the deviations (an, bn, cn) is not 0. If it is determined that the position of the next tentative welded portion stored in memory is different from the actual position of the temporary welded portion, the process proceeds to step S11 and all deviations (an, bn, cn) are 0. As described above, after correcting the memory coordinates (xn, yn, zn) of the next temporary welding portion, the process proceeds to step S10, and welding is continued. In that case, the memory coordinates (xn, yn, zn) of this temporary welding part
With the change of, the main welding line will be corrected between the next temporary welding portion and the welding start portion, and between the adjacent next temporary welding portion. The main welding will be performed along this line.

Next, the control unit 24 determines in step S12 the memory coordinates (x0, y) of the welding start portion.
0, z0) and the actual coordinates (xn ', y) of the next temporary welding site
n ', zn') and the deviation (ano, bno, cno) is calculated, and then the deviation (ano, bn) is calculated in step S13.
o, cno) are all determined to be within a predetermined error range ± e, the next temporary welding site is the welding start site,
In other words, assuming that the main welding has been performed around the annular flanges F1 and F2, a welding end signal is output to the robot actuator 23 in step S14. On the other hand, the deviation (an
at least one of o, bno, cno) is an error range ± e
If it is determined that it is not within the range, it is determined that the main welding has not yet been made around the annular flanges F1 and F2, and the process returns to step S8, and the next temporary welding portion (n = 2) is the same as above. Required memory coordinates (xn, yn,
zn) correction and main welding line correction,
The main welding by the welding robot 22 is continued.

In this way, the control unit 2
In No. 4, the main welding line is continuously corrected with reference to the actual position of the temporary welding portion X ′ until the main welding is completed. After the completion of the main welding, the flange clamps 16 ... 16 are released in step S15, and the work clamps 14, 14 are released in step S16, and then a carry-out signal is output to a work carrying-out device (not shown) to perform the main welding. The side frame inner assembly W1 and the side frame outer W2 are attached to the main welding station 13
The welding work is completed by carrying out the welding work.

Next, the operation of this embodiment will be described.

That is, in the temporary welding station 1, spot welding is performed by irradiating the flanges F1 and F2 with the laser beam using the clamp jig 3, so that the temporary welding portion X'is resistance welded using the pressure electrode. As a result, the flanges F1 and F2 are prevented from being lifted up during the temporary welding.

In this case, the clamp jigs 3 are attached at the corners of the flanges F1 and F2 with a small gap and a tighter space than the straight portions.
The distance X ′ also becomes smaller, and as a result, the corners of the flanges F1 and F2 having poor flatness are densely spot-welded to suppress the degree of floating, and the main welding line set later by the control unit 24. Will be set smoothly along the corner,
The main welding will be smoothly and continuously performed.

In the main welding station 13, the welding robot 22 irradiates the laser beam with the laser torch 20 along the main welding line to perform the main welding. In that case, the control unit 2 is used.
4 receives the analysis signals from the CCD camera 18 and the image analysis device 19, and the hue and lightness of the temporary welding portion X ′ that has turned black in the flanges F1 and F2, and the flange F similarly.
After the temporary welding portion X ′ is identified by detecting the optical difference between the hue and the brightness of the other portions in 1 and F2, the temporary position is temporarily determined based on the actual position of the identified temporary welding portion X ′. Correctly set the welding line and the main welding line.

Therefore, for example, as shown in FIG. 6, a temporary welding line X0 is set as a welding start site, and a temporary welding line or a main welding line L obtained by sequentially connecting adjacent temporary welding regions X1, X2, ... Is set. This main welding line L
When irradiating and scanning the laser beam B from the temporary welding site X0 along the direction, the flanges F1 and F2 are thermally deformed during the main welding and the actual positions of the temporary welding sites X1, X2 ,. As described above, when the main welding deviates from the initial position and, as a result, the main welding is performed along the initial main welding line L, the positional relationship between the main welding portion and the temporary welding portion does not match, and the lap welding is performed accurately. Even when it is not possible, the actual temporary welding parts X1, X
2, the temporary welding line or the main welding line L is corrected, and the laser beam B is scanned along the corrected main welding line L, so that the lap welding is an actual temporary welding portion. X1, X2, ... Are always performed under the correct positional relationship.

Further, as shown by the chain line in FIG. 7, an error occurs in the carry-in and positioning of the temporarily welded workpieces W1 and W2 to the main welding station 13, and the welding start portion X0 and the temporary welding portions X1, X2. Even if the actual coordinates of ... deviate from the memory coordinates, the memory coordinates of the welding start site X0 are corrected and changed to the actual coordinates of the actual welding start site X0 indicated by the chain line, and the preset main welding is performed. The line L is corrected with reference to the positions of the actual temporary welding parts X1, X2, ...
Since it is set, the above lap welding is the correct welding start site X
After starting from 0, the actual temporary welding parts X1, X2, ...
Will always be performed under the correct positional relationship.

In the above embodiment, the spot welding performed in the temporary welding station 1 is performed by using the clamp jig 3 with a built-in torch. Instead of the clamp jig 3, as shown in FIG. In addition, a laser oscillated by a laser oscillator may be transmitted to the laser torch 31 provided on the arm 30 through the optical fiber 32 and emitted from the torch 31 by using a welding robot. Also, as shown in FIG. 9, without using a torch,
The laser beam B may be irradiated onto the flanges F1 and F2 by the condenser lens 33 and the reflecting mirror 34.

Then, in these cases, when a flange clamp for fixing the flanges F1 and F2 is separately used, as shown in FIG. 10, for example, the through hole 35a is formed.
Using the clamp 35 formed with
When the beam B is applied to the flanges F1 and F2 via
The temporary welding site X ′ can be set at the mounting position of the clamp 35, and as shown in FIG. 11, the position of the temporary welding site X ′ is set by irradiating the beam B to the vicinity of both sides of the clamp 36. You may.

On the other hand, in the above embodiment, the main welding line is set to coincide with the temporary welding line in order to perform the lap welding at the main welding station 13. However, the present invention is not limited to this, and the main welding line is temporarily set. If it is set at a predetermined distance from the temporary welding line based on the welding line, for example, edge welding as shown in FIG. 12, fillet welding as shown in FIG. 13, or flare welding as shown in FIG. And so on.

In this case, for example, a welding robot having a clamp jig 37 as shown in FIG. 15 at the tip of the arm can be used. The clamp jig 37 includes small arms 39, 39 for clamping above and below the laser torch 38.
Are arranged so as to face each other, and the flanges F are provided by the clamp rollers 40, 40 provided on the small arms 39, 39, respectively.
While gripping 1, F2, this gripped flange F
While irradiating the side end faces of 1 and F2 with the beam B, the whole is moved along the end faces. When the irradiation of the beam B is performed toward the mating surfaces of the flanges F1 and F2, the edge welding or flare welding shown in FIG. 12 or 14 can be performed and only the side end surface of one flange is performed. Then, the fillet welding shown in FIG. 13 can be performed. Then, in this case, by controlling the clamp rollers 40 and 40 to move along the temporary welding line, the actual position of the temporary welding site X ′ and the irradiation site of the beam B (main welding site) are determined. The positional relationship between them will always be maintained correctly.

Further, in the above embodiment, the side frame inner assembly W1 and the side frame outer W of the automobile are arranged.
The case where 2 and 2 are joined by the flanges F1 and F2 formed around these door mounting portions has been described, but the present invention is not limited to this, and as shown in FIG. The invention can be applied to joining various works such as continuously joining the roof assembly W3 to the side frame W12.

[0057]

As described above, according to the present invention,
Since the temporary welding of the work is performed using a high-density energy beam such as a laser beam, the temporary welding site is not pressed, and the floating of the joint portion during the temporary welding is suppressed.

Then, in performing the main welding by irradiating the laser beam along the main welding line, the main welding line is based on the temporary welding line obtained by sequentially connecting adjacent ones of the temporary welding portions. The temporary welding line is an actual temporary welding line, because the temporary welding site is a temporary welding site that is identified by detecting a physical difference between the temporary welding site and another site in the temporarily welded joint. The position of the portion is set as a reference, and the main welding line is set with this temporary welding line as a reference. As a result, the main welding is always performed at the correct position with respect to the temporary welding portion.

In this case, if the main welding line is set based on the temporary welding line so as to match the temporary welding line,
Lap welding can be performed, and edge welding or fillet welding can be performed when set at a predetermined distance from the temporary welding line.

Further, since the temporary welded portion is identified by detecting the physical difference between the welded portion and other portions, the change in the lightness or hue of the work surface due to melting or oxidation during the temporary welding, or the change in shape, etc. Based on the above, the temporary welded portion can be reliably identified.

In particular, when the optical difference is detected as the physical difference, the joint portion is melted and oxidized as a result of being irradiated with the high-density energy beam, and the brightness is changed to black compared with other portions. The temporary welded portion can be reliably identified when the color or the hue changes.

On the other hand, if the interval of the temporary welding at the corner portion of the joint portion is made smaller than that of the straight portion, the corner portion having poor flatness is densely spot-welded to suppress the problem of floating and the main welding line. Can be set smoothly along the corner.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a temporary welding station according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of spot welding work performed at the temporary welding station.

FIG. 3 is a control system diagram of the present welding station in the embodiment of the present invention.

FIG. 4 is an explanatory diagram of a laser torch used in the main welding station.

FIG. 5 is a flow chart for controlling main welding performed in the main welding station.

FIG. 6 is an explanatory diagram of an operation of main welding performed at the main welding station.

FIG. 7 is likewise an explanatory view of the action of the main welding.

FIG. 8 is an explanatory diagram of another spot welding operation performed at the temporary welding station.

FIG. 9 is likewise an explanatory view of another spot welding operation.

FIG. 10 is likewise an explanatory view of another spot welding operation.

FIG. 11 is likewise an explanatory view of another spot welding operation.

FIG. 12 is an explanatory diagram of another main welding operation performed at the main welding station.

FIG. 13 is also an explanatory view of another main welding work.

FIG. 14 is likewise an explanatory view of another main welding operation.

FIG. 15 is an explanatory diagram of a welding robot used for another main welding operation.

FIG. 16 is an explanatory view of another work to be joined in the present invention.

[Explanation of symbols]

 1 Temporary welding station 2,14 Work clamp 3 Torch built-in clamp jig 9,20b Condenser lens 10,25 Laser oscillator 11,26 Transmission optical system 13 Main welding station 16,35,36 Flange clamp 18 CCD camera 19 Image analysis device 20,38 Laser torch 22 Welding robot 24 Control unit F1, F2 Flange L Main welding line W1 Side frame inner assembly W2 Side frame outer X'Temporary welding site X0 Welding start site

Claims (6)

[Claims] 1. A welding method in which a joint portion of a work is spot-temporarily welded at a predetermined interval and then continuously main-welded, wherein the temporary welding is performed by using a high-density energy beam, It is obtained by detecting the physical difference between the temporary welded part and the other part in the temporarily welded joint to identify the temporary welded part and connecting the adjacent parts of the identified temporary welded parts in order. The main welding line is set on the basis of the temporary welding line to be used, and the high-density energy beam is irradiated along the set main welding line to perform the main welding. Welding method used. 2. The physical difference detected when identifying the temporary welded portion is an optical difference.
The welding method described in. 3. The welding method according to claim 1, wherein the interval at which the corner portion of the joint portion is temporarily welded is smaller than the interval at which the straight portion is temporarily welded. 4. A welding device for spot-temporarily welding a joint portion of a work at a predetermined interval and then continuously performing main welding, wherein the joint portion of the work is irradiated with a high-density energy beam. A temporary welding device that performs welding, a detection unit that detects a physical difference between a temporary welding site and another site in a joint part temporarily welded by the temporary welding system, and a physical difference detected by the detection unit Identification means for identifying the temporary welding part based on the temporary welding part, provisional welding line setting means for setting a temporary welding line by sequentially connecting adjacent parts of the temporary welding parts identified by the identification means, and the temporary welding line setting Main welding line setting means for setting the main welding line based on the temporary welding line set by the means, and irradiating the high-density energy beam along the main welding line set by the main welding line setting means Accordingly, a main welding apparatus for performing the main welding is provided, and a welding apparatus using a high-density energy beam. 5. The welding apparatus according to claim 4, wherein the physical difference detected by the detecting means is an optical difference. 6. The welding device according to claim 4, wherein an interval at which the temporary welding device temporarily welds the corner portion of the joint portion is smaller than an interval at which the linear portion is temporarily welded.