JPS63115680A - Welding method and its device - Google Patents

Abstract

PURPOSE:To prevent a defective work from being fed to a next process by deciding a welding defect by the abnormal current of a wire and stopping the welding, and subsequently, putting the defective work into a defective housing case, and releasing the welding stop after the housing is confirmed. CONSTITUTION:Work 11 is fixed onto a work table 7 in a welding chamber 6 by a fixing member 13, and thereafter, the table 7 is brought to a half rotation and CO2 welding is executed by a torch 14. In this case, by a current detecting sensor, the variation of a welding current conducted to a welding wire is detected, and when an abnormal current caused by a welding failure is detected, it is displayed on the defective detecting lamp 27 of a control part 3, and simultaneously, welding is stopped. Subsequently, when a worker removes a defective work 11 and puts it in a defective housing case 2, its housing is confirmed automatically by a limit switch and a welding stop state is released. In such a way, it can be prevented that the work of a welding defect is fed to the next process.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a welding method and a welding apparatus for performing welding operations on various workpieces.

(Prior art) The steering wheel core metal used as the core material of a steering wheel attached to an automobile etc. is a spoke part core metal,
It consists of a ring core metal, a boss plate, a boss, etc., which are each integrated by welding.

In recent years, the equipment that welds these welds has become increasingly automated, greatly contributing to improvements in work efficiency and product precision.

(Problem to be solved by the invention) However, when welding is carried out using this automated device, whether or not the workpiece has been reliably welded is determined by the individual worker's welding bag. I was checking the next work one by one.

Therefore, there is a risk that the worker may inadvertently overlook the welding process and send the welded workpiece to the next process.

Structure of the Invention (Means for Solving the Problems) Therefore, in order to solve the above problems, the present invention includes a step of detecting a change in welding current flowing through a welding wire during welding work on a workpiece, and a welding method in the step. a step of stopping the welding work by detecting an abnormal current caused by the defect; a step of storing the defective welding work in a defective product storage box; and a step of storing the defective welding work in the defective product storage box. The first means (hereinafter referred to as the first invention) is adopted, which comprises a step of canceling the stopped state of the welding operation by confirming that the welding operation is stopped.

Further, a current detecting means for detecting a change in current during welding is provided between the torch and the welding power source, and the control section receives a signal from the current detecting means and is instructed to stop the welding operation of the torch. A second means (hereinafter referred to as the second invention) is provided, wherein the welding apparatus is provided with a defective product storage box inside or outside the welding device to store a defective workpiece detected by the current detection means. Adopted.

Further, a current detection means for detecting a current change during welding is provided between the torch and the welding power source, and the control section includes an instruction section for receiving a signal from the current detection means and instructing the torch to stop welding work. A defective product storage box is provided inside or outside the welding device to store the defective welded work detected by the current detection means, and the defective product storage box stores the defective welded work. A third means (hereinafter referred to as the third invention) is adopted in which a release means is provided for detecting this and instructing the instruction section to release the stoppage of the operation.

(Function) According to the present invention, a change in the current flowing through the welding wire during welding work on a workpiece is detected, and a welding failure is determined based on the abnormal current detected during this detection, and the welding work is stopped. After that, when this workpiece with a welding defect is placed in the defective product storage box, the welding operation stop state is canceled and the next welding operation can be performed.This prevents the defective welding workpiece from being welded again and sent to the next process. can.

According to the second aspect of the present invention, during welding work on a workpiece, an abnormal current caused by a welding defect among the current flowing through the welding wire of the torch is detected by the current detection means provided between the torch and the welding power source. The instruction section receives the signal and outputs it to the control section to stop the welding operation. Therefore, by taking out defective workpieces from the work table and storing them in the defective product storage box, it is possible to reliably prevent workpieces with defective welding from being erroneously sent to the next process.

According to the third aspect of the present invention, during welding work on a workpiece, the current detecting means provided between the torch and the welding power source detects an abnormal current caused by a welding defect among the currents flowing through the welding wire of the torch. The instruction section receives the signal and outputs it to the control section to stop the welding operation. Thereafter, when the defective product is taken out from the table where the welding work has been stopped and stored in the defective product storage box, the instruction unit instructs the control unit to release the stoppage of operation only upon input from the release means provided in the defective product storage box. Output.

Therefore, similarly to the second invention, it is possible to reliably prevent a workpiece with a welding defect from being re-welded and sent to the next process.

(Example) Hereinafter, an example in which the present invention is embodied in a welding device for welding and fixing a boss to a boss plate which is a part of a steering wheel core metal of an automobile will be described with reference to FIGS. 1 to 8.

This welding device includes a welding device main body 1 that supports a workpiece and performs welding work, a defective product storage box 2 provided on the side thereof,
It is composed of a control section 3 that manages these controls, and each member will be explained in detail below.

[Welding device main body 1] The welding device main body 1 has a vertically movable door 5 on the front side. A welding chamber 6 whose opening is covered by the door 5 is formed inside the welding device main body 1, and its inner bottom surface is grounded to the earth. A disc-shaped work table 7 is provided. This work table 7
is rotatably supported by a drive means (not shown) (indicated by the arrow in FIG. 1), and is supported so as to be tiltable (indicated by the arrow in FIG. 2) toward the operator side, that is, the door 5 side. A cylindrical locking member 8 is attached to the approximate center of the work table 7, and a boss 9 and a boss plate 10 (hereinafter simply referred to as a boss core metal 11), which are workpieces, are mounted on the upper surface of the locking member 8! ! 25&. The locking member 8 is made of a conductive material, and the welding current applied to the boss core metal 11 is grounded through the work table 7 to which the locking member 8 is fixed. There is. Clamp members 12 are attached to both sides of the work table 7 with the locking member 8 interposed therebetween, so that the boss core metal 11 is securely fixed to the locking member 8.

On the upper surface of the welding chamber 6 facing the boss 9 of the boss core metal 11 placed on the locking member 8, there is a boss fixing member 13 that presses and fixes the upper surface of the boss 9 by an air cylinder (not shown). It is attached so that it can move up and down and can move horizontally.

At both ends of the upper surface of the welding chamber 6, a total of two torches 14 are attached facing each other, the tips of which are disposed close to the boundary between the boss 9 of the boss portion core metal 11 and the boss plate 10. As shown by the arrow in the figure, as the work table 7 rotates, substantially the entire circumference of the boundary between the boss 9 and the boss plate 10 is welded.

As shown in FIG. 3, the torch 14 includes a cylindrical torch main body 16 having a through hole 14a through which a welding wire 15 and CO2 (carbon dioxide) gas are inserted, and a cylindrical torch body 16 attached to the tip thereof. shaped tip 17 and torch body 16
C that is provided near the tip of the through hole 14a and passed through the through hole 14a.
It is composed of a plurality of gas holes 16a that spout O2 gas, and a cylindrical gas nozzle 18 that covers the outer periphery of the gas holes 16a. The welding wire 15 can be moved forward and backward by a motor (not shown) provided at the base end of the torch 14, and the welding wire 15 is connected to the torch 1 from a welding power source 20.
150A-300A at voltage of 15V-30V via 4
A current of is applied.

A current detection sensor 19 is installed between the torch 14 and the welding power source 20 as a current detection means for detecting the current flowing through the wire 15 during the welding operation. is detected and the fact that a welding defect has occurred is outputted to an instruction section 23, which will be described later. As shown in FIG.
The current flowing through the torch 14 exhibits a substantially constant value under normal welding conditions, and the current collection rate decreases when the welding wire 15 is not fed during welding, when the welding arc does not fly, and due to internal wear of the torch 14. If this occurs, the current value will drop extremely (as shown in part P in Figure 7), and if various wiring (not shown) is frayed and short-circuited, the current value will rise extremely (as shown in part Q in Figure 7). ) and the welding will not be done properly. Also, the upper limit of this variation (7th
The lower limit (indicated by the dashed-dotted line Y in Figure 7) and the lower limit (indicated by the dashed-dotted line Y in Figure 7) are based on the applied current value expanded by about 10%, and in this example, the lower limit is 130A and the upper limit is 330A. There is. Furthermore, the current detection sensor 19
has a built-in timer (not shown), so that even if the current change exceeds the upper and lower limits, a temporary change that does not exceed a predetermined time will not be detected as a welding defect.

[Defective Product Storage Box 2] A defective product storage box 2 is provided below the side of the welding device main body 10 and has an opening 2a on the front surface for storing the boss part core metal 11 that is defective in welding, and the opening 2a has a lid. 21 is rotatably supported. A limit switch 22 is attached to the upper surface of the defective product storage box 2, and when the boss core metal 11 of a defective product opens this M21 and enters the defective product storage box 2, the lI2
The back surface of 1 comes into contact with the limit switch 22 to operate the limit switch 22. And this limit switch 22
The instruction unit 23, which has output the signal, informs the control unit 3 that it confirms that the defective boss core metal 11 has been accommodated, cancels the welding operation stop state described later, and installs a new boss core metal. 11 on the work table 7 to start new welding. Although not shown, the storage box 2 is provided with a counter.
The number of defective boss core metals 11 that have entered the storage box 2 can be seen at a glance.

[Control unit 3] On the side opposite to the storage box 2 of the welding device main body 1 is a control plate 2.
A control unit 3 with 4 is mounted. The control board 24 has a power switch 2 that turns on and off the power of the entire device.
5a, a plurality of switches 25c that individually actuate the door 5, work table 7, and boss fixing member 13, and a detection switch that enables the plurality of switches 25c and starts detecting current changes. 25b, a start switch 26 for starting welding work, and a defective product detection lamp 27 for informing that a welding defect has occurred.

The control unit 3 is controlled by a microcomputer (not shown), and, as shown in FIG. 7, operates the work table 7, boss fixing member 13, door 5, and torch 14 individually according to the following work procedure. It has become.

Next, the welding operation sequence of this apparatus will be explained with reference to FIG.

That is, when the start switch 26 is pressed, the door 5 is closed and the work table 7 is tilted from the operator's side to the welding chamber 6 side, and the boss fixing member 13 is lowered to the upper surface of the boss 9 and the boss core metal 11 securely fixed. Thereafter, at the same time as the work table 7 rotates approximately half a rotation, the welding wire 15 is sent out from the tip of the torch 14 and current is applied to perform CO2 welding work. When the welding work is completed, the work table 7 is tilted toward the operator, and the door 5 is lowered to open the welding room 6.
appears.

During this work, due to a welding defect, the current value during welding was higher than the above-mentioned predetermined value (indicated by X and Y in Figure 6).
When the current detection sensor 19 moves to the Q section in the figure) or downward (the P section in FIG. 6), it is detected by the current detection sensor 19 and output to the instruction section . The instruction section 23 then instructs the control section 3 to turn on the defective product detection lamp 27 provided on the control board 24 and to stop the welding operation. Further, in this case, even if the start switch 26 is pressed, the welding operation cannot be continued again.

In this case, the detection switch 25b is temporarily turned off to extinguish the defective product detection lamp 27. Thereafter, the detection switch 25b is turned ON again, the work table 7, the boss fixing member 13, and the door 5 are operated individually to take out the defective boss core metal 11 and store it in the defective product storage box 2.

Then, the limit/seven toss isochi 22 attached to the upper surface of the defective product storage box 2 is activated, and a signal is outputted to the instruction section 23. Then, the instruction section 23 instructs the control section 3 to perform the above-described series of welding operations when the start switch 26 is pressed to perform a new welding process.

Further, although not shown, the control board 24 is provided with a counter, which corresponds to the counter of the defective product storage box 2.

Next, a method of welding the boss portion core metal 11 using the welding device configured as described above will be described together with its functions and effects.

First, as shown by the dashed line in FIG. 2, the boss portion core metal 11 is placed 8i12 on the upper surface of the locking member 8 of the work table 7 tilted toward the operator, and is fixed by the clamp member 12.

Next, when the start switch 26 is pressed, the field 5 rises and covers the opening of the welding chamber 6. Simultaneously with this operation, the work table 7 is tilted horizontally, and the upper surface of the boss 9 is fixed by the boss fixing member 13. after that,
As shown in FIG. 4, the welding wire 15 is sent out from the two torches 14 to start CO2 welding, and at the same time, the work table 7 is rotated approximately half a turn to completely cover approximately the boundary between the boss 9 and the boss plate 10. Weld the circumference. When this welding is completed, the field 5 is lowered and the work table 7 is lowered.
The whole unit tilts toward the operator, and the series of welding operations stops.

Welding wire 15 is not fed during the COY welding,
If the welding arc does not fly or the current collection rate decreases due to internal wear of the torch 14, resulting in a welding failure, the current value will be extremely reduced (as shown in part P in FIG. 6). Further, when various wirings are frayed and short-circuited, resulting in a welding failure, the current value increases extremely (as shown in part P in FIG. 6). Therefore, when these abnormal currents occur, the current detection sensor 19 detects the current change,
It outputs to the instruction section 23 that a welding defect has occurred. Then, the instruction section 23 turns on the defective product detection lamp 27 to stop the entire series of welding operations, and also instructs the control section 3 so that the welding operation cannot be started even if the start switch 26 is pressed again. Therefore, the operator turns off the detection switch 25b to turn off the defective product detection lamp 27, and then switches the detection switch 25b again to continue current detection and operate the work table 7, boss fixing member 13, and door 5. Turn on. Thereafter, the work table 7, the boss fixing member 13, and the door 5 are operated individually to take out the defective boss core metal 11 from the welding chamber 6 and store it in the defective product storage box 2. Then, the limit switch 2 attached to the top of the defective product storage box 2
2 operates and outputs to the instruction section 23, and the start switch 2
Pressing 6 instructs the control unit 3 to perform a new welding process.

Therefore, welding work is performed continuously by repeating the series of operations described above.

As described above, according to this embodiment, a change in the welding current during welding is detected to determine a welding defect, and this welding operation is stopped, and when a welding defect occurs, the core of the boss part of the welding defect is determined. Unless the gold 11 is completely removed from the welding chamber 6 and stored in the storage box 2, welding cannot be performed on the next new boss core metal 11. It is possible to reliably prevent II from being sent to the next process.

Further, if a defective product occurs, the work cannot be continued even if the start switch 26 is pressed halfway, so it is possible to prevent a defective product from being welded halfway and being sent to the next process.

Further, since the criterion for determining a welding defect is based on the current flowing through the welding wire 15, more accurate judgment can be made than based on a voltage change with a small rate of change. Furthermore, since the current detection sensor 19 is equipped with a timer so as not to detect current disturbances in a short period of time, malfunctions are less likely to occur.

Furthermore, since the work table 7 can be tilted toward the operator, the operator can work in a comfortable posture without entering the welding chamber 6.

Further, since counters are provided in the defective product storage box 2 and the control board 24, the number of stored defective products and the number of defective products generated can be immediately matched.

Note that the present invention is not limited to the above embodiments,
For example, it is possible to modify and embody it as shown below.

(1) In the above embodiment, the limit switch 22 was used as a means for releasing the defective product storage box 3, but in addition to this, m
21 may be omitted, and a phototube or the like may be used to detect storage of the defective product storage box 2.

(2) In the above embodiment, the present invention was used for welding a steering wheel core metal used in a steering wheel of an automobile, but it can also be applied to a welding apparatus for various parts other than automobiles.

(3) In the above embodiment, an apparatus for performing CO□ welding is shown, but the present invention may also be embodied as an apparatus for performing TAG welding or MIG welding.

Effects of the Invention As detailed above, according to the first and third inventions, the next welding operation cannot be performed unless the defective welded workpiece is stored in the defective product storage box, so that the defective welded workpiece is This has the excellent effect of reliably preventing the welding from being re-welded and being sent to the next process. Further, according to the second invention, a welding defect is detected by a change in the current flowing through the welding wire during workpiece welding, and the detected defective workpiece is placed in a defective product storage box. This has the excellent effect of reliably preventing the transfer of

[Brief explanation of the drawing]

1 to 8 show an embodiment embodying the present invention,
Fig. 1 is a perspective view showing the entire welding device, Fig. 2 is a partial side view showing the tilting state of the work table, Fig. 3 is a sectional view showing the torch, and Fig. 4 shows the welding state of the boss core metal 11. 5 is a sectional view showing the defective product storage box 2, FIG. 6 is a diagram showing changes in welding current, FIG. 7 is a circuit diagram showing the connection state of the control section, and FIG. 8 is a sectional view showing the defective product storage box 2. is a flowchart showing the working procedure of the welding device. 2...Defective product storage box 3...Control unit 7...Work table 11...Boss core metal 14...Torch
15... Welding wire 19... Current detection sensor 2
0...Welding power source. Patent applicant - Ei Kogyo Toyoda Gosei Co., Ltd. Agent Patent attorney On 1) Hironobu Figure 2 ar! A Me14 1e)a 16 Figure 6

Claims (1)

[Claims] 1. Welding wire (
15) A step of detecting a change in the welding current flowing through the step, a step of stopping the welding operation by detecting an abnormal current caused by a welding defect in the step, and a step of storing the defective welded workpiece (11) in a defective product storage box. (2) a step of storing the
A welding method comprising the step of canceling the stopped state of the welding operation by confirming that the defective welding workpiece (11) is stored in a defective product storage box (2). 2. A table (7) that supports the workpiece (11), a torch (14) that performs welding work on the workpiece (11), and a welding power source that supplies welding current to the welding wire (15) of the torch (14). (20) and a control section (
3), a current detection means (19) for detecting a current change during welding is provided between the torch (14) and the welding power source (20), and the control section (3) is provided with an instruction section (23) that receives a signal from the current detection means (19) and stops the welding operation of the torch (14), and the current detection means (19) is provided inside or outside the welding device. A welding device characterized in that a defective product storage box (2) is provided for storing a workpiece (11) with a welding defect detected by the welding device. 3. The welding apparatus according to claim 2, wherein the table (7) is provided so as to be tiltable and rotatable. 4. A table (7) that supports the workpiece (11), a torch (14) that performs welding work on the workpiece (11), and a welding power source that supplies welding current to the welding wire (15) of the torch (14). (20) and a control section (
3), a current detecting means (19) for detecting a current change during welding is provided between the torch (14) and the welding power source (20), and a current detecting means (19) is provided between the torch (14) and the welding power source (20); ) is provided with an instruction section (23) that receives a signal from the current detection means (19) and stops the welding operation of the torch (14), and the current detection means (19) is provided inside or outside the welding device. A defective product storage box (2) is provided to store a workpiece (11) with a welding defect detected by the method, and it is detected that the defective product storage box (2) stores a workpiece (11) with a welding defect. a release means (2) for instructing the instruction section (23) to release the stoppage of operation;
2) A welding device characterized by being provided with. 5. The welding apparatus according to claim 4, wherein the table (7) is provided so as to be tiltable and rotatable. 6. The welding device according to claim 4, wherein the release means (22) is a limit switch.