JPH11104888A - Welding equipment and welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To weld in a state that a mutual gap of mutually superposed plate stocks is reduced as much as possible. SOLUTION: After a pressurizing rod 15 is advanced by an operation of a rod servomotor 17 so as to advance by a prescribed quantity toward the forward side (work W side) from a tip end of a MIG welding torch 5, the pressurizing rod 15 is advanced together with a MIG welding torch 5 by an operation of a servomotor 7 so as to come into contact with an upper plate W1 in the mutually superposed work W. After the pressurizing rod 15 is brought into contact with the upper plate W1 , a rapid rise of a pressurizing load to the upper plate W1 by the pressurizing rod 15 is detected with a load sensor 23, the upper plate W1 is judged to come into close contact with a lower plate W2 without any gap at this time point, the torch servomotor 7 is stopped to drive, and fillet welding in the mutually superposed part of the upper plate W1 and the lower plate W2 is executed with the MIG welding torch 5 under this state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding apparatus and a welding method for welding and joining mutually superposed plate materials.

[0002]

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to perform welding while minimizing the gap between mutually superposed plate materials.

[0003]

In order to achieve the above object, according to the first aspect of the present invention, a welding operation is performed at a predetermined distance from one side of mutually superimposed plate members so as to connect the plate members to each other. The welding torch is configured to have a welding torch to be weld-joined, and a plate pressing member that presses the plate on the side on which the welding operation is to be performed to bring the two plates into close contact with each other when performing the welding operation with the welding torch.

According to the welding apparatus having such a configuration, the generation of a gap between the plate members is eliminated by pressing the plate members from one side of the mutually overlapped plate members by the plate member pressing member. Perform welding work with a torch.

According to a second aspect of the present invention, in the configuration of the first aspect of the present invention, the plate pressing member can be moved in a direction approaching or moving away from the plate by the first drive mechanism, and the welding torch can be moved in the second direction. With the first drive mechanism that supports the plate material pressing member, the drive mechanism can move in a direction approaching and separating from the plate material.

According to the above configuration, the plate pressing member moves forward by the operation of the first drive mechanism and is positioned a predetermined amount forward of the tip of the welding torch. In this state, the operation of the second drive mechanism causes The welding torch moves forward toward the plate, and the plate pressing member supported by the first drive mechanism also moves forward to press the plate so as to eliminate the gap between the plates. In a state where the plate pressing member is pressing the plate,
The tip of the welding torch is at a predetermined distance from the surface of the plate material, and the welding operation is performed in this state.

According to a third aspect of the present invention, in the configuration of the second aspect of the present invention, the first drive mechanism is configured such that the tip of the plate material pressing member is located ahead of the tip of the welding torch by a predetermined amount by a control unit to which welding conditions are input. It is controlled to be on the side.

According to the above configuration, when the control unit inputs welding conditions, for example, a welding current value, the first drive mechanism is driven based on the input value to move the plate pressing member from the tip of the welding torch. Move forward so as to be on the fixed amount front side.

According to a fourth aspect of the present invention, in the configuration of the second aspect of the present invention, a load sensor for detecting a pressing load on the plate by the plate pressing member is provided, and the second driving mechanism operates together with the first driving mechanism. A control unit is provided for stopping the operation of the second drive mechanism when the detection value of the load sensor sharply increases after the plate member pressing member moving toward the plate member comes into contact with the plate member.

[0010] According to the above configuration, the operation of the second drive mechanism allows the plate pressing member to come into contact with the plate, and then continues the pressing operation on the plate by the plate pressing member, so that the plates overlap each other. When the gap disappears, the pressing load rises sharply. At this time, the operation of the second drive mechanism is stopped, and in this state, the welding operation using the welding torch is performed.

According to a fifth aspect of the present invention, in the configuration of the first aspect, the plate material pressing member includes a roller that moves relative to the plate material while rotating along the welded portion in a pressed state.

According to the above configuration, when the welding torch relatively moves along the welding portion while performing the welding operation, the roller of the plate pressing member moves relatively while rotating on the plate while pressing the plate.

According to a sixth aspect of the present invention, after the plate driving member is moved forward by a predetermined amount from the tip of the welding torch by the operation of the first driving mechanism, the operation is performed by the operation of the second driving mechanism. The plate pressing member is moved forward together with the welding torch so as to contact one side of the plate members overlapped with each other, and after the plate pressing member comes into contact with the plate member, the pressing load on the plate member by the plate pressing member sharply increases. At this point, the operation of the second drive mechanism is stopped, and the welding operation using the welding torch is performed.

According to the above welding method, the welding operation by the welding torch is performed at the time when the pressing load of the plate pressing member against the plate is sharply increased and the gap between the plates is almost eliminated, and the plate pressing member is brought into contact with the plate. A welding operation is performed by a welding torch at a position separated by a predetermined amount from the plate material to be welded.

[0015]

According to the first aspect of the present invention, the plate material is pressed by the plate pressing member from one side of the plate materials overlapped with each other, and the welding operation is performed by the welding torch in a state where the gap between the plate materials is eliminated. So that the plate material mutual,
It is welded and joined in a state where it is in close contact with no gap, and the welding quality can be improved.

According to the second aspect of the present invention, the operation of the first drive mechanism moves the plate pressing member forward so that the plate drive member is positioned a predetermined distance ahead of the tip of the welding torch. By the operation described above, the welding torch moves forward toward the plate, and the plate pressing member supported by the first drive mechanism also moves forward to press the plate so as to eliminate the gap between the plates. The gap between the sheet material and the plate material is secured at a predetermined level, and welding can be performed in a state where the plate materials are in close contact with each other, so that welding quality can be improved.

According to the third aspect of the present invention, the first driving mechanism is controlled such that the tip of the plate pressing member is located ahead of the tip of the welding torch by a predetermined amount in accordance with the welding conditions. When welding work in a state where the plate material is pressed,
The distance between the surface of the sheet material and the tip of the welding torch becomes appropriate in accordance with the welding conditions, and higher quality welding work can be performed.

According to the fourth aspect of the present invention, after the plate pressing member comes into contact with the plate, further in the process of continuing the pressing operation on the plate by the plate pressing member, when the load detected by the load sensor suddenly increases, By stopping the pressing operation and performing the welding operation in this state, a high-quality welding operation in a state in which the plate members are in close contact with each other can be performed.

According to the fifth aspect of the present invention, when the welding torch relatively moves along the welding portion while performing the welding operation,
Since the roller of the plate material pressing member rotates on the plate material while pressing the plate material, high-quality welding in a state in which the plate materials are in close contact with each other can be performed even in a welding operation while the welding torch is moving relative to the plate material.

According to the invention of claim 6, when the pressing load of the plate pressing member against the plate is sharply increased and the gap between the plates is almost eliminated, the welding operation by the welding torch is performed, and the plate pressing member is used. Since the welding operation is performed by the welding torch at a position separated by a predetermined amount from the plate material with which the contact is made, extremely high quality welding operation can be performed.

[0021]

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

FIG. 1 is a perspective view of a welding apparatus showing an embodiment of the present invention, FIG. 2 is a view taken in the direction of arrow A in FIG. 1, and FIG. 3 is a left side view of FIG. In this welding apparatus, the lower end of the tip shaft 1 of a robot (not shown) is mounted on the upper surface on the right side of the base plate 3 in FIG. 2, and the upper surface on the left side of the base plate 3 moves the MIG welding torch 5 and the like up and down. The lower end of the torch servomotor 7 as a second drive mechanism for the motor is mounted.

The MIG welding torch 5 is fixed via a boss 11 to a torch fixing part 9a projecting rightward in FIG. 3 of the intermediate plate 9 arranged below the base plate 3. The intermediate plate 9 is connected to the tip (lower end) of the drive shaft 13 of the torch servomotor 7, and the drive shaft 13 moves forward and backward by the driving of the torch servomotor 7, and the welding torch 5 is transferred to the work W together with the intermediate plate 9. It moves up and down to approach and separate. Workpiece W, the upper plate W ₁ composed of two thin plates and a lower plate W ₂ which was superimposed on each other, since this time is particularly thin, mutually not completely close contact,
A gap S is formed between each other. Such work W
Respect, the upper plate W ₁ superimposed on the lower plate W ₂ edge P (FIG. 3
So-called fillet welding is performed by the welding torch 5 in accordance with the above.

The base plate 3 in FIG. 2 of the intermediate plate 9
A lower end of a rod servomotor 17 as a first drive mechanism for vertically moving a pressing rod 15 as a plate material pressing member for pressing the work W is mounted on the upper surface of the portion projecting further to the left. A tip plate 19 is disposed below the intermediate plate 9, and the tip plate 19 is connected to a tip (lower end) of a drive shaft 21 of the rod servomotor 17, and driven by the rod servomotor 17. The push rod 15 moves up and down together with the tip plate 19 so as to approach and separate from the work W. As shown in FIG. 3, the MIG welding torch 5 is bent toward the vicinity of the tip (lower end) of the pressing rod 15 described above.

The pressing rod 15 is attached via a load sensor 23 to the lower surface of the end plate 19 on the side of the MIG welding torch 5 in FIG. A rotatable roller 27 is provided. At the lower end of the load sensor 23, a mounting boss 23a is formed, and a screw portion 15a provided at the upper end of the pressing rod 15 is screwed into a female screw portion of the mounting boss 23a. It is attached.

The detected value of the load sensor 23 is input to a controller 29 which is a control unit, and the controller 29 controls the torch servomotor 7 and the rod servomotor 17.
The operation of the entire welding apparatus is controlled, for example, by controlling the drive of the welding machine.

Next, the control operation of the controller 29 in the above welding apparatus will be described with reference to the flowchart of FIG. When the tip axis 1 of the robot is moved to the welding point and positioned, the MIG welding current (I) is input by the robot (program) (step 101), and the target position M of the rod servomotor 17 is determined based on the input value. _A is calculated (step 103). This target position M _A
As shown in FIG. 5, the distance L between the tip of the pressing rod 15 moved forward and backward by the rod servomotor 17 and the tip of the MIG welding torch 5, in other words, the distance between the surface of the workpiece W during the welding operation and the This corresponds to the distance to the welding torch 5, and is calculated by M _A = aI (a is a coefficient). That is, M _A is proportional to the MIG welding current I, and the value of the MIG welding current I determines the distance (M _A ) between the surface of the workpiece W and the tip of the welding torch 5 during welding.

[0028] M _A calculated is output to the rod servomotor 17 (step 105), thereby the rod servomotor 17 is driven as shown in FIG. 5, the drive shaft 21 is advanced downwardly A tip plate 19 provided at the tip moves integrally with the load sensor 23 and the pressing rod 15 toward the workpiece W. At this time, the controller 29 receives the input of the current position M _A1 of the rod servo motor 17 from the servo motor 17 (step 107), and determines whether the current position M _A1 matches the target position M _A (step 107). Step 109) If they match, the distance L corresponding to the input MIG welding current I is obtained, and the drive of the rod servomotor 17 is stopped.

After the drive of the rod servomotor 17 is stopped,
To torch servomotor 7 outputs a driving signal M _B (value of driving at a constant speed) (step 111), thereby torch servomotor 7 is driven as shown in FIG. 6, the drive shaft 13 downwardly The intermediate plate 9 which has advanced and is provided at the end thereof moves closer to the work W together with the rod servomotor 17, the pressing rod 15, the MIG welding torch 5 and the like, and the roller 27 comes into contact with the work W. . At this time, the controller 29 has received the input of the detection value T of the load sensor 23 corresponding to the pressing load on the work W by the pressing rod 15 (step 113), and the change amount T / At is sequentially calculated (step 115).

Further, the controller 29 inputs the current position M _B1 of the torch servo motor 7 to the servo motor 7.
(Step 117), whether the current position M _B1 is equal to or less than the operation limit value S ₁ of this servomotor 7 (M _B1 ≦ S ₁ )
Is determined (step 119). Here, the current position M _B1
There if it exceeds the operating limit values S ₁ is the operation limit abnormal output of the servo motor 7 is performed by, for example, to light the example warning lamp (step 121), to stop the operation.

On the other hand, when the current position M _B1 is equal to or less than the operation limit value S ₁ , the operation is continued, and the detection value T
Is the threshold value (device strength limit) S of the load sensor 23.
₂ (T ≦ S ₂ ) (step 12)
3). Here, if the current position M _B1 exceeds the threshold S ₂ is the abnormal overload output of the load sensor 23 is performed by, for example, to light the example warning lamp (step 12
5) Stop the operation.

Conversely, when the detected value T is equal to or smaller than the threshold value S ₂ , the operation is continued, and the amount of change T / Δt of the detected value T per unit time is the difference of the output change of the load sensor 23. threshold S ₃ or whether it is determined whether _{(T / Δt ≧ S 3)} ( step 127). If the variation T / Δt is below the threshold value S ₃ , the process returns to the step 111 for operating the torch servomotor 7 and the subsequent operations are repeated, while the variation T / Δt is a threshold. If that is the value S ₃ above, as shown in FIG. 6, it is determined that the gap S is exhausted to the upper plate W ₁ is shown in Figure 5 in close contact with the lower plate W _2,
Stopping the output M _B to the torch servomotor 7 (step 129).

FIG. 7 shows the detected value T of the load sensor 23 as (a), the change amount T / Δt of the detected value T as (b), and the time after the roller 27 contacts the upper plate W _1. an illustration with the lapse of t, the upper plate W ₁ is the lower plate W ₂ at time t ₁
It can be seen that at this time t ₁ , the amount of increase in the detected value T with respect to time t increases, and at the same time, the amount of change T / Δt also sharply increases.

After the torch servomotor 7 is stopped in step 129, a welding start signal is output to the robot and the welding machine (step 131), as shown in FIG. 8, which is an enlarged view of the arrow B in FIG. Then, the welding operation is started.
During this welding operation, the roller 27 moves in a direction along the welding line, that is, in a direction orthogonal to the paper surface in FIG. 8, while the roller 27 keeps pressing the work W. Incidentally, those indicated by the reference numeral 31 which projects from the distal end of the welding torch 5 in FIG. 8 is a wire, weld bead 33 on the mating portion between the upper plate W ₁ and the lower plate W ₂ by the melting of the wire 31 is formed The upper plate W ₁ and the lower plate W ₂ are welded to each other.

During the above welding operation, the upper plate W ₁ is pressed by the roller 27 at the tip of the pressing rod 15 and the lower plate W ₂
The upper plate W ₁ and the lower plate W ₂ are securely joined to each other by the welding bead 33, and high quality welding can be performed. Work W
The distance L between the surface of the MIG welding torch 5 and the tip of the MIG welding torch 5 can be accurately set according to the welding conditions (MIG welding current I), and a higher quality welding operation can be performed.

FIG. 9 is a perspective view showing a part of the inside of a rear seat of an automobile body to be welded by the above welding apparatus, and FIG. 10 is an enlarged view of C in FIG. It is -C sectional drawing. The flange 41a bent upward from the floor panel 41 is butted against the reinforcing plate 39 interposed between the side sill outer 35 and the side sill inner 37, and fillet welding is performed on the butted portion using the above welding device. As a result, a weld bead 33 is formed, and the reinforcing plate 39 and the floor panel 41 are joined by welding.

9 and 10, welding is performed by the MIG welding torch 5 while pressing the flange portion 41a of the floor panel 41 with the roller 27 at the tip of the pressing rod 15. Such a welding portion is difficult to spot weld because the flange portion 35a of the side sill outer 35 protrudes longer and deeper than a portion on the front side of the vehicle body (the direction of arrow F in FIG. 9). And
By using the welding device in such a portion, a high-quality vehicle body structure can be obtained.

Although the MIG welding torch 5 is used in the above embodiment, a TIG welding torch may be used.

[Brief description of the drawings]

FIG. 1 is a perspective view of a welding apparatus showing one embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrow A in FIG. 1;

FIG. 3 is a left side view of FIG. 2;

FIG. 4 is a flowchart showing a control operation of a controller in the welding device of FIG. 1;

FIG. 5 is an operation explanatory view showing a state in which the pressing rod is brought closer to the work from the state of FIG. 2;

6 is an operation explanatory view showing a state in which the MIG welding torch is brought close to the work together with the pressing rod from the state of FIG. 5;

7A and 7B are transition diagrams of respective values over time after a roller at the tip of a pressing rod contacts a work in the welding apparatus of FIG. 1, wherein FIG. 7A is a detection value of a load sensor, and FIG. Is the amount of change per unit time.

FIG. 8 is an enlarged view as seen from the arrow B in FIG. 6;

9 is a perspective view showing a part of the inside of a rear seat of a body of an automobile on which a welding operation is performed by the welding device of FIG. 1;

FIG. 10 is an enlarged sectional view taken along the line CC of FIG. 9;

[Explanation of symbols]

W ₁ upper plate (plate material) W ₂ lower plate (plate material) 5 MIG welding torch (welding torch) 7 torch servomotor (second drive mechanism) 15 pressing rod (plate material pressing member) 17 rod servomotor (first) Drive mechanism) 23 Load sensor 27 Roller 29 Control unit

Claims (6)

[Claims] 1. A welding torch for performing a welding operation at a predetermined distance from one side of a mutually overlapped plate material to weld and join the plate materials to each other, and performing a welding operation using the welding torch. A welding device comprising: a plate pressing member that presses a plate on a side on which a welding operation is performed to bring both plate materials into close contact with each other. A first driving mechanism for moving the plate pressing member toward and away from the plate, and a welding torch supporting the plate pressing member by a second driving mechanism; The welding apparatus according to claim 1, wherein the welding apparatus is movable in a direction in which the driving mechanism moves toward and away from the plate material. 3. The first drive mechanism is controlled by a control unit to which welding conditions are input such that the tip of the plate pressing member is located forward of the tip of the welding torch by a predetermined amount. 2. The welding device according to 2. 4. A load sensor for detecting a pressing load on the plate by the plate pressing member is provided, and after the plate pressing member that moves toward the plate together with the first drive mechanism by the operation of the second drive mechanism contacts the plate. 3. The welding apparatus according to claim 2, further comprising a control unit for stopping the operation of the second drive mechanism when the value detected by the load sensor sharply increases. 5. The welding apparatus according to claim 1, wherein the plate pressing member includes a roller that moves relative to the plate while rotating along a welding portion in a pressed state. 6. An operation of the first drive mechanism moves the plate pressing member forward by a predetermined amount from the tip of the welding torch, and then moves the plate pressing member by an operation of the second drive mechanism. Is moved forward together with the welding torch to make contact with one side of the plate material superimposed on each other, after the plate material pressing member comes into contact with the plate material, when the pressing load on the plate material by the plate material pressing member sharply increases, Second
A welding operation using the welding torch while the operation of the drive mechanism is stopped.