Submerged arc welding system

Abstract

To provide a submerged arc welding system capable of preventing overturning of a carriage.SOLUTION: A welding system A1 for performing submerged arc welding includes: a welding torch 3 for projecting a tip of a welding wire, and welding an object W to be welded; a wire feeding device 5 for feeding the welding wire; a control device 1 for controlling the wire feeding device 5; a carriage 4 which is mounted with the welding torch 3, and is moved along a welding line; and an inclination detection part (press button 45) for detecting that the carriage 4 is inclined by a predetermined amount or more. The control device 1 includes a feeding control part 13 for stopping feeding of the welding wire by the wire feeding device 4, when the inclination detection part detects that the carriage 4 has been inclined.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a submerged arc welding system for performing submerged arc welding. [Background technology]

[0002] Submerged arc welding has been known for some time. In submerged arc welding, granular flux is spread on the workpiece, a welding wire is fed into the flux, and an arc is generated between the tip of the welding wire and the workpiece to perform welding. In submerged arc welding, welding is performed while moving the welding point by, for example, moving a carriage along the welding line. In submerged arc welding, a thick plate can be welded with high efficiency by passing a large current through a thick welding wire. Patent Document 1 discloses an example of a submerged arc welding device. In the submerged arc welding device, a wire reel wound with a welding wire, a hopper filled with flux, a welding head, and the like are mounted on a traveling carriage. The traveling carriage travels on a rail provided along the welding line. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-90410 A Summary of the Invention [Problem to be solved by the invention]

[0004] In submerged arc welding, the welding point is covered with flux. Therefore, even if the welding wire comes into contact with the workpiece and a short circuit occurs, the worker has a hard time noticing the short circuit. If the welding wire continues to be fed without noticing the short circuit, the cart may tip over.

[0005] FIG. 9 is a simplified diagram for explaining the overturning of a carriage due to a short circuit. In the welding system A100 shown in FIG. 9(a), a wire reel 6, a wire feeder 5, and a welding torch 3 are mounted on a carriage 4. This is a simplified diagram seen from the rear of the carriage 4 in the traveling direction. The tip of the welding wire fed by the wire feeder 5 protrudes from the tip of the welding torch 3 as an electrode 8, and an arc is generated between the electrode 8 and the workpiece W to perform welding. The tip of the electrode 8 is covered with flux 79. Note that FIG. 9 illustrates the electrode 8 so that it can be seen through the flux 79. Even if the tip of the welding wire (electrode 8) comes into contact with the workpiece W during welding and a short circuit occurs, it cannot actually be seen from the outside. Therefore, the operator does not notice the short circuit and does not stop welding. Therefore, the wire feeder 5 continues to feed the welding wire, and the tip of the welding wire (electrode 8) pierces the molten pool of the workpiece W.

[0006] In submerged arc welding, a welding wire with a large diameter is generally used. Therefore, the welding wire is not likely to buckle. In addition, since the wire feeder 5 is capable of feeding the welding wire with a high torque, the welding wire is not likely to slip on the pressure roll. Therefore, if the operator does not notice the occurrence of a short circuit and the feeding of the welding wire continues, a moment acts on the carriage 4 in the direction of the arrow Y around the point X as shown in FIG. 9(b). This causes the carriage 4 to become unstable and tilted, and the carriage may tip over. The tip over of the carriage is not limited to the occurrence of a short circuit during welding, but may also occur when the welding wire is continuously inched during non-welding.

[0007] The present invention has been devised in light of the above circumstances, and an object of the present invention is to provide a submerged arc welding system capable of preventing the cart from tipping over. [Means for solving the problem]

[0008] The submerged arc welding system provided by the present invention is a submerged arc welding system for performing submerged arc welding, and includes a welding torch that extends a tip of a welding wire to weld the workpiece, a wire feeding device that feeds the welding wire, a control device that controls the wire feeding device, a cart on which the welding torch is mounted and which moves along the weld line, and a tilt detection unit that detects when the cart is tilted by a predetermined amount or more, and the control device includes a feed control unit that stops the feeding of the welding wire by the wire feeding device when the tilt detection unit detects tilt.

[0009] In a preferred embodiment of the present invention, the tilt detection unit includes a contact detection unit that detects contact with the workpiece, and when the contact detection unit detects contact, detects tilt, and the contact detection unit is positioned on the opposite side of the center of gravity of the cart from the position of the welding torch in a plan view.

[0010] In a preferred embodiment of the present invention, the trolley has a protrusion that protrudes from the side and bends vertically downward, the protrusion has a tip surface that faces vertically downward, and the contact detection unit is a push button and is arranged on the tip surface.

[0011] In a preferred embodiment of the present invention, the tilt detection unit includes a tilt sensor that detects tilt information indicating the tilt of the trolley, and a judgment unit that judges whether the trolley is tilted by a predetermined amount or more based on the tilt information.

[0012] In a preferred embodiment of the present invention, the feed control unit causes the wire feeder to stop feeding the welding wire and then feed the welding wire in the opposite direction. Effect of the Invention

[0013] According to the present invention, when the tilt detection unit detects that the carriage is tilted by a predetermined amount or more, the feed control unit stops the feeding of the welding wire by the wire feeder. Therefore, the submerged arc welding system according to the present invention can prevent the carriage from tipping over due to continued feeding of the welding wire. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram for explaining a welding system according to a first embodiment, where (a) is a block diagram showing the overall configuration of the welding system, and (b) is a block diagram showing the internal configuration of a welding power supply and a control device. [Diagram 2] 2 is a simplified diagram of a carriage of the welding system according to the first embodiment, viewed from the rear in the traveling direction. FIG. [Diagram 3] 5 is an example of a flowchart illustrating a tip-over prevention control process performed by the control device. [Figure 4] 5 is a timing chart for explaining a tip-over prevention control process performed by the control device. [Diagram 5] FIG. 4 is a simplified diagram showing a modified example of the carriage according to the first embodiment. [Figure 6] 11 is a simplified diagram of a carriage of a welding system according to a second embodiment, viewed in a direction perpendicular to the traveling direction and the vertical direction. [Figure 7] FIG. 13 is a simplified plan view of the carriage for explaining the positions of a welding torch and a push button relative to the carriage. FIG. [Figure 8] 11A and 11B are diagrams for explaining a welding system according to a third embodiment, where FIG. 11A is a block diagram showing the overall configuration of the welding system, and FIG. 11B is a block diagram showing the internal configurations of a welding power supply and a control device. [Figure 9] FIG. 11 is a simplified diagram for explaining the tipping over of a carriage due to a short circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0016] [First embodiment] Fig. 1 and Fig. 2 are diagrams for explaining a welding system A1 according to a first embodiment. Fig. 1(a) is a block diagram showing the overall configuration of welding system A1. Fig. 1(b) is a block diagram showing the internal configuration of welding power supply 2 and control device 1. Fig. 2 is a simplified diagram showing a carriage 4 of welding system A1 as viewed from the rear in the traveling direction.

[0017] The welding system A1 is a welding system for performing submerged arc welding. As shown in FIG. 1(a), the welding system A1 includes a control device 1, a welding power supply device 2, a welding torch 3, a carriage 4, a wire feeder 5, a wire reel 6, a spreader 7, and an electrode 8. The welding system A1 causes the spreader 7 to spread granular flux 79 and the wire feeder 5 to feed the welding wire into the flux 79 while moving the carriage 4 along the welding line of the workpiece W. The welding wire is supplied from the wire reel 6. The welding power supply device 2 converts AC power supplied from a commercial power supply P into power suitable for welding, outputs the power, and generates an arc between the electrode 8, which is the tip of the welding wire, and the workpiece W inside the flux 79. Welding is performed by the heat of the arc. As a result, welding is performed along the welding line of the workpiece W.

[0018] Welding torch 3 guides the welding wire fed by wire feeder 5 to the welding point. The tip of the welding wire becomes electrode 8 protruding from the tip of welding torch 3. Welding torch 3 is provided with a contact tip (not shown) that is disposed at the tip and is electrically connected to welding power supply 2. Welding power supply 2 applies a welding current to the welding wire that is in contact with the contact tip. The welding torch 3 is fixed to the carriage 4 and moves with the movement of the carriage 4. The welding torch 3 may be directly fixed to the carriage 4, or may be indirectly fixed via an arm or the like. In this embodiment, as shown in Fig. 2, the welding torch 3 is fixed to the end of an arm extending from the carriage 4 to the right in the traveling direction.

[0019] The carriage 4 carries the wire reel 6, the wire feeder 5, the sprayer 7, and the welding torch 3 and moves along the weld line of the workpiece W. The control device 1 may also be mounted on the carriage 4. As shown in FIG. 2, the welding torch 3 and the wire feeder 5 are fixed to the end of an arm extending from the carriage 4 in the right direction with respect to the traveling direction, and are disposed on the right side of the carriage 4. Although not shown in FIG. 2, the sprayer 7 and the wire straightener are also disposed on the right side of the carriage 4. On the other hand, the wire reel 6 is fixed to the end of an arm extending from the carriage 4 in the left direction with respect to the traveling direction, and is disposed on the left side of the carriage 4. The positions of the parts mounted on the carriage 4 are not limited to those described above. The parts are disposed so that the center of gravity of the carriage 4 is located near the center of the carriage 4. The welding torch 3 may be configured to be movable up and down or left and right. In addition, the carriage 4 may be provided with a balancer to suppress changes in the position of the center of gravity of the carriage 4 in response to the movement of the welding torch 3, or in response to a decrease in the amount of flux in the hopper of the spraying device 7, or a decrease in the welding wire on the wire reel 6.

[0020] In this embodiment, as shown in Fig. 2, the cart 4 has a protruding portion 42 protruding from the left side surface 41. The protruding portion 42 is bent vertically downward and has a tip surface 43 facing vertically downward. A push button 45 is disposed on the tip surface 43. When the push button 45 is pressed, it outputs a press signal to the control device 1 (see Fig. 1(b)).

[0021] The control device 1 performs various controls of the welding system A1. The control device 1 may be a general-purpose computer with a program installed therein for performing various controls of the welding system A1, or may be a dedicated device for controlling the welding system A1. The control device 1 moves the carriage 4 at a predetermined moving speed. The moving speed is set according to the material and thickness of the workpiece W. The control device 1 instructs the spraying device 7 to start and stop spraying the flux 79. The spraying device 7 may start and stop spraying the flux 79 manually. The control device 1 instructs the wire feeder 5 to start and stop feeding the welding wire and the feeding speed of the welding wire. The feeding speed is set according to the welding current to be set. The control device 1 instructs the welding power source 2 to output power. The control device 1 also performs control to prevent the carriage 4 from falling over. Details of the control will be described later.

[0022] Welding power supply 2 converts AC power supplied from commercial power source P into AC power of a desired frequency and outputs the AC power. As shown in Fig. 1(b), welding power supply 2 includes a rectifying and smoothing circuit 21, an inverter circuit 22, a transformer 23, a rectifying and smoothing circuit 24, an inverter circuit 25, a current sensor 26, a voltage sensor 27, and a control circuit 28.

[0023] The rectifying and smoothing circuit 21 converts AC power input from the commercial power source P into DC power and outputs it. The inverter circuit 22 converts the DC power input from the rectifying and smoothing circuit 21 into high-frequency power and outputs it by switching the switching elements according to an output control drive signal input from the control circuit 28. The transformer 23 transforms the high-frequency voltage output by the inverter circuit 22 and outputs it to the rectifying and smoothing circuit 24.

[0024] The rectifying and smoothing circuit 24 converts the high frequency power input from the transformer 23 into DC power and outputs it. The inverter circuit 25 converts the DC power input from the rectifying and smoothing circuit 24 into AC power and outputs it by switching the switching elements according to a switching drive signal input from the control circuit 28. The inverter circuit 25 switches between a positive polarity in which the potential of the output terminal a (connected to the workpiece W) is higher than the potential of the output terminal b (connected to the welding wire), and a reverse polarity in which the potential of the output terminal a is lower than the potential of the output terminal b.

[0025] The current sensor 26 detects the output current of the welding power supply 2, and in this embodiment, is disposed on a connection line connecting one output terminal of the inverter circuit 25 and the output terminal a. The output current of the welding power supply 2 detected by the current sensor 26 is approximately equal to the current flowing through the electrode 8. The current sensor 26 outputs a current value signal corresponding to the detected current instantaneous value to the control circuit 28 and the control device 1. The position where the current sensor 26 is disposed is not limited. The voltage sensor 27 detects the output voltage of the welding power supply 2, and in this embodiment, detects the inter-terminal voltage between the output terminal a and the output terminal b. The voltage is approximately equal to the voltage applied between the workpiece W and the tip of the electrode 8. The voltage sensor 27 outputs a voltage value signal corresponding to the detected voltage instantaneous value to the control circuit 28 and the control device 1. The voltage sensor 27 may detect the voltage between the lead wire attached to the welding torch 3 and the lead wire attached to the workpiece W.

[0026] Control circuit 28 is a circuit for controlling welding power supply 2, and is realized by, for example, a microcomputer. Control circuit 28 receives a current value signal from current sensor 26, a voltage value signal from voltage sensor 27, and various command signals and various set values ​​from control device 1. Control circuit 28 then outputs drive signals to inverter circuit 22 and inverter circuit 25. The configuration of welding power supply 2 is not limited.

[0027] Next, the anti-toppling control performed by the control device 1 will be described. The anti-toppling control is a control for preventing the cart 4 from tipping over. Specifically, when the control device 1 detects that the cart 4 has tilted by a predetermined amount or more, it stops the feeding of the welding wire by the wire feeder 5. As shown in FIG. 1(b), the control device 1 includes a timing unit 11 and a feed control unit 13 as a configuration for the anti-toppling control.

[0028] The clock unit 11 is a component for measuring time. The clock unit 11 starts and stops measuring time and initializes the measured time in response to an instruction from the feed control unit 13.

[0029] The feed control unit 13 is configured to control the wire feeder 5. The feed control unit 13 instructs the wire feeder 5 to start and stop feeding of the welding wire and the feeding speed of the welding wire. When a pressing signal is input from the push button 45, the feed control unit 13 instructs the wire feeder 5 to stop feeding of the welding wire, thereby stopping the feeding of the welding wire.

[0030] For example, if the tip of the welding wire (electrode 8) contacts the workpiece W during welding and a short circuit occurs, as the wire feeder 5 continues to feed the welding wire, a moment acts on the cart 4 to rotate in the direction of the arrow Y about the point X as shown in FIG. 2(b). This causes the cart 4 to become unstable and tilted to the left. However, if the cart 4 tilts to a predetermined degree or more before it falls over, the push button 45 contacts the workpiece W and is pressed. When the push button 45 is pressed, it outputs a pressing signal to the control device 1 (see FIG. 1(b)). Note that even if the cart 4 tilts to the left by a predetermined degree or more, for example, when the welding wire is continuously inched during non-welding, the push button 45 contacts the workpiece W or the floor and is pressed. In other words, the push button 45 arranged on the tip surface 43 of the protrusion 42 constitutes a tilt detection unit that detects contact with the workpiece W or the floor and detects that the cart 4 has tilted to the left by a predetermined degree or more.

[0031] In this manner, when the cart 4 is tilted to the left by more than a predetermined amount, the push button 45 is pressed and a press signal is input to the feed control unit 13, which causes the wire feeder 5 to stop feeding the welding wire. This prevents the cart 4 from tipping over due to continued feeding of the welding wire.

[0032] However, when the push button 45 is pressed, the carriage 4 is already tilted. The feed control unit 13 also has a function of correcting this tilt. Specifically, the feed control unit 13 instructs the wire feeder 5 to stop feeding the welding wire, and then instructs the wire feeder 5 to start feeding the welding wire in the opposite direction (so-called retraction). Then, the feed control unit 13 instructs the wire feeder 5 to stop retracting after a predetermined time T has elapsed. The predetermined time T is set to a time required for the carriage 4, which has been tilted until the push button 45 is pressed, to return to its original position. The predetermined time T is set to an appropriate time based on experiments and simulations. The predetermined time T may be a fixed value, or may be changed depending on the feed speed immediately before the feeding of the welding wire is stopped. When the feed control unit 13 instructs the wire feeder 5 to start retracting, the feed control unit 13 instructs the timer unit 11 to start timing, and compares the time counted by the timer unit 11 with the predetermined time T. When the predetermined time T has elapsed, the feed control unit 13 instructs the retraction to be stopped, stops the timing by the timer unit 11, and initializes the measured time to "0".

[0033] Note that the feed control unit 13 may retract the welding wire by a length required to return the tilted carriage 4 to its original position, instead of setting a time for performing the retraction. Specifically, the feed control unit 13 may reversely rotate the motor (not shown) of the wire feeder 5 by a number of rotations corresponding to the length.

[0034] 3 is an example of a flowchart showing a tip-over prevention control process performed by the control device 1. The tip-over prevention control process is started, for example, when the control device 1 is started.

[0035] First, it is determined whether or not a pressing signal has been input from push button 45 (S1). If a pressing signal has not been input (S1: NO), the process returns to step S1, and the determination in step S1 is repeated. On the other hand, if a pressing signal has been input (S1: YES), the feeding of the welding wire is stopped (S2). Specifically, feed control unit 13 instructs wire feeder 5 to stop feeding of the welding wire. This causes wire feeder 5 to stop feeding the welding wire. Next, retraction of the welding wire is started (S3). Specifically, feed control unit 13 instructs wire feeder 5 to start feeding the welding wire in the opposite direction. This causes wire feeder 5 to start retracting the welding wire. Next, it is determined whether or not a predetermined time T has elapsed (S4). Specifically, feed control unit 13 determines whether or not the time counted by timer unit 11 is equal to or greater than the predetermined time T. The timer unit 11 measures the time from when the retraction is started. If the predetermined time T has not elapsed (S4: NO), the process returns to step S4, and the determination in step S4 is repeated. That is, the feed control unit 13 waits until the time measured by the timer unit 11 reaches the predetermined time T. If the predetermined time T has elapsed (S4: YES), the retraction is stopped (S5), and the tip-over prevention control process is terminated.

[0036] It should be noted that the process shown in the flowchart of FIG. 3 is merely an example, and the overturn prevention control process performed by the control device 1 is not limited to the above.

[0037] FIG. 4 is a timing chart for explaining the overturn prevention control process performed by the control device 1. FIG. 4(a) shows the change over time of the pressing signal input from the push button 45. FIG. 4(b) shows the change over time of the time measured by the timer 11. FIG. 4(c) shows the change over time of the feed speed of the welding wire. When the welding wire is fed in the forward direction, the feed speed is a positive value, and when the welding wire is fed in the reverse direction, the feed speed is a negative value. Note that the vertical and horizontal axes of the timing chart shown in FIG. 4 are appropriately enlarged or reduced for ease of understanding, and each waveform shown is simplified, exaggerated, or emphasized for ease of understanding.

[0038] Until time t1, no pressing signal is input from push button 45 (OFF). At time t1, a pressing signal is input from push button 45 (ON), and feed control unit 13 instructs wire feeder 5 to stop feeding the welding wire. As a result, the feeding speed of the welding wire decreases, and becomes "0" at time t2. Note that the feeding speed decreases with an inclination due to inertia after the instruction to stop feeding. Also, at time t1, after instructing wire feeder 5 to stop feeding the welding wire, feed control unit 13 instructs wire feeder 5 to start feeding (retracting) the welding wire in the opposite direction. As a result, from time t2, wire feeder 5 starts retracting the welding wire, and the feeding speed of the welding wire decreases (the speed in the opposite direction increases), and becomes a predetermined retract speed. Note that the feeding speed decreases with an inclination due to inertia after the instruction to start retracting.

[0039] Furthermore, at time t1, timing is started by the timing unit 11, and the measured time increases according to the elapsed time. Then, at time t3, the elapsed time reaches a predetermined time T, so the feed control unit 13 instructs the wire feeder 5 to stop retraction. After the instruction to stop retraction, the feed speed increases with an incline due to inertia (the speed in the opposite direction decreases), and becomes "0" at time t4. Since the predetermined time T has elapsed, at time t3, the timing unit 11 stops timing and initializes the measured time to "0".

[0040] Next, the operation and effects of the welding system A1 according to this embodiment will be described.

[0041] According to this embodiment, the push button 45 is disposed on the tip surface 43 of the protruding portion 42 that protrudes from the left side surface 41 of the carriage 4 and is bent downward in the vertical direction. Therefore, when the welding wire protrudes too much from the tip of the welding torch 3 and the carriage 4 tilts to the left by more than a predetermined amount, the push button 45 comes into contact with the workpiece W or the floor, etc., and is pressed, outputting a pressing signal to the control device 1. When the pressing signal is input from the push button 45, the feed control unit 13 instructs the wire feeder 5 to stop feeding the welding wire. As a result, the wire feeder 5 stops feeding the welding wire. Therefore, the welding system A1 can prevent the carriage 4 from tipping over due to the continued feeding of the welding wire. The present invention is particularly effective when setting conditions before the actual welding work (welding in which each parameter is changed and trial welding is performed to determine the welding conditions). Furthermore, the present invention detects that the cart 4 has actually tilted and stops the feeding of the welding wire, thereby more accurately preventing the cart 4 from tipping over compared to a case in which the feeding of the welding wire is stopped by predicting that the cart 4 will tilt.

[0042] Moreover, according to this embodiment, push button 45 is disposed on the left side of cart 4. This allows appropriate detection of the welding wire protruding too far from the tip of welding torch 3 disposed on the right side of cart 4, causing cart 4 to tilt to the left by a predetermined amount or more. Also, according to this embodiment, push button 45 is disposed on tip surface 43 of protruding portion 42 that protrudes from left side surface 41 of cart 4 and is bent downward in the vertical direction. This allows push button 45 to be appropriately pressed when cart 4 tilts to the left by a predetermined amount or more.

[0043] Furthermore, according to this embodiment, when a pressing signal is input from push button 45, feed control unit 13 instructs wire feeder 5 to stop feeding of the welding wire, and then instructs it to start feeding the welding wire in the opposite direction (so-called retraction). Wire feeder 5 retracts the welding wire. This allows welding system A1 to correct the inclination of carriage 4 that is already inclined at the time when feeding of the welding wire is stopped. Feed control unit 13 instructs it to stop retracting a predetermined time T after the instruction to start retracting. By retracting for the predetermined time T, welding system A1 can return the inclination of carriage 4 to the original state (horizontal state).

[0044] In this embodiment, the case where the feed control unit 13 issues a command to stop feeding and then issues a command to retract has been described, but this is not limited to this. When a pressing signal is input from the push button 45, the feed control unit 13 may only issue a command to stop feeding, and may not need to issue a command to retract.

[0045] In the present embodiment, the case has been described in which the push button 45 is disposed on the tip surface 43 of the protruding portion 42 that protrudes from the side surface 41 of the cart 4 and is bent downward in the vertical direction, but the present invention is not limited to this. For example, the protruding portion 42 may protrude from the upper surface of the cart 4 as shown in FIG. 5(a), or may protrude from the rear surface (front surface) of the cart 4 as shown in FIG. 5(b). The push button 45 may also be disposed on the side surface of the protruding portion 42 instead of the tip surface 43 as shown in FIG. 5(b). In other words, the push button 45 may be fixed to the cart 4 and disposed on the left side of the cart 4 (opposite side to the welding torch 3) so as to be pressed when the welding wire protrudes too much from the tip of the welding torch 3 and the cart 4 is tilted.

[0046] Further, in the present embodiment, the case where the push button 45 is disposed on the tip surface 43 of the protrusion 42 has been described, but this is not limited thereto. The trolley 4 may be provided with a contact sensor or the like that detects contact with the workpiece W or the floor, instead of the push button 45. Furthermore, the trolley 4 may be provided with a distance sensor that detects the distance from the workpiece W or the floor, instead of the push button 45, and the control device 1 may detect that the trolley 4 has tilted by a predetermined amount or more based on the detected distance. In other words, it is sufficient for the trolley 4 to be configured to detect that the trolley 4 has tilted by a predetermined amount or more.

[0047] In this embodiment, since the welding torch 3 is disposed on the right side of the cart 4, the push button 45 is disposed on the left side of the cart 4. When the welding torch 3 is disposed on the left side of the cart 4, the push button 45 is disposed on the right side of the cart 4.

[0048] Second Embodiment FIG. 6 is a diagram for explaining a welding system A2 according to a second embodiment, and is a simplified diagram of a carriage 4 of the welding system A2 as viewed from a direction perpendicular to the traveling direction and the vertical direction. In FIG. 6(a), an arrow indicates the traveling direction of the carriage 4. That is, the carriage 4 moves in the direction of the arrow. In FIG. 6, elements that are the same as or similar to those in the first embodiment are given the same reference numerals as those in the first embodiment. The welding system A2 according to this embodiment differs from the welding system A1 according to the first embodiment in the position of the push button 45.

[0049] In this embodiment, the welding torch 3 is disposed on the front side of the cart 4. The push button 45 is disposed on the rear side of the cart 4. Specifically, the protruding portion 42 protrudes from the side surface 44 on the rear side of the cart 4 and is bent vertically downward. The push button 45 is disposed on the tip surface 43 of the protruding portion 42 facing vertically downward. For example, if a short circuit occurs during welding, when the wire feeder 5 continues to feed the welding wire, a moment acts to rotate the cart 4 in the direction of the arrow Y about the point X as shown in FIG. 2(b). This causes the cart 4 to become unstable in a state in which it is tilted backward. However, if the cart 4 tilts backward by a predetermined amount or more before it falls over, the push button 45 comes into contact with the workpiece W and is pressed. This allows the cart 4 to be appropriately detected as having tilted backward by a predetermined amount or more.

[0050] According to this embodiment, the push button 45 is disposed on the rear side of the cart 4. Therefore, when the cart 4 is tilted rearward by more than a predetermined amount, the push button 45 comes into contact with the workpiece W or the floor, etc., and is pressed, outputting a pressing signal to the control device 1. When the pressing signal is input from the push button 45, the feed control unit 13 instructs the wire feeder 5 to stop feeding the welding wire. As a result, the wire feeder 5 stops feeding the welding wire. Therefore, the welding system A2 can prevent the cart 4 from tipping over due to the continued feeding of the welding wire. Also, according to this embodiment, since the push button 45 is disposed on the rear side of the cart 4, it is appropriately detected that the cart 4 is tilted rearward by more than a predetermined amount. Also, according to this embodiment, the push button 45 is disposed on the tip surface 43 of the protruding portion 42 that protrudes from the side surface 44 on the rear side of the cart 4 and is bent downward in the vertical direction. As a result, the push button 45 is appropriately pressed when the cart 4 is tilted rearward by more than a predetermined amount. Also in this embodiment, welding system A2 has a similar configuration to welding system A1, and can therefore achieve the same effects as welding system A1.

[0051] In this embodiment, since the welding torch 3 is disposed on the front side of the carriage 4, the push button 45 is disposed on the rear side of the carriage 4. When the welding torch 3 is disposed on the rear side of the carriage 4, the push button 45 is disposed on the front side of the carriage 4.

[0052] Also, the cart 4 may have push buttons 45 disposed on both the rear and left sides. That is, the cart 4 may have both a protruding portion 42 protruding from a rear side surface 44 of the cart 4 and a protruding portion 42 protruding from a left side surface 41 of the cart 4, and a push button 45 may be disposed on each tip surface 43. With this configuration, the feeding of the welding wire can be stopped both when the cart 4 is tilted rearward by a predetermined amount or more and when the cart 4 is tilted leftward by a predetermined amount or more.

[0053] As can be seen from the first and second embodiments, push button 45 is disposed on the opposite side of the welding torch 3 with respect to the center of gravity of cart 4 in plan view. Fig. 7 is a simplified diagram of cart 4 viewed in plan, illustrating the positions of welding torch 3 and push button 45 with respect to cart 4. In Fig. 7, welding torch 3 is disposed on the right front side with respect to center of gravity G of cart 4. In this case, push button 45 is desirably disposed on both the left side of cart 4 (see 45a) and the rear side of cart 4 (see 45b).

[0054] Third Embodiment FIG. 8 is a diagram for explaining a welding system A3 according to a third embodiment. FIG. 8(a) is a block diagram showing the overall configuration of the welding system A3. FIG. 8(b) is a block diagram showing the internal configuration of the welding power supply 2 and the control device 1. In FIG. 8, elements that are the same as or similar to those in the first embodiment are given the same reference numerals as those in the first embodiment. The welding system A3 according to this embodiment differs from the welding system A1 according to the first embodiment in that the cart 4 is provided with an inclination sensor 46 that detects inclination information indicating the inclination of the cart 4, instead of the protrusion 42 and the push button 45.

[0055] In this embodiment, the cart 4 does not include the protrusion 42 and the push button 45, but instead includes an inclination sensor 46. The inclination sensor 46 is, for example, a three-axis acceleration sensor that detects acceleration in each axial direction and outputs the detected value to the control device 1. The position where the inclination sensor 46 is disposed on the cart 4 is not limited.

[0056] The control device 1 according to this embodiment further includes a determination unit 14. The determination unit 14 calculates the degree of inclination of the cart 4 based on the detection value input from the inclination sensor 46, and determines whether the calculated degree of inclination is equal to or greater than a predetermined value. If the calculated degree of inclination is equal to or greater than the predetermined value, the determination unit 14 determines that the cart 4 is inclined by the predetermined value or more, and outputs a determination signal to the feed control unit 13. If the determination signal is input from the determination unit 14, the feed control unit 13 instructs the wire feeder 5 to stop feeding of the welding wire, thereby stopping the feeding of the welding wire.

[0057] The configuration of the inclination sensor 46 is not limited as long as it can detect inclination information indicating the inclination of the cart 4. For example, the inclination sensor 46 may be a gyro sensor. The inclination sensor 46 may calculate the degree of inclination of the cart 4 based on the detection value, output the degree of inclination to the control device 1, and the determination unit 14 may determine whether the input degree of inclination is equal to or greater than a predetermined value. Instead of the inclination sensor 46 in the cart 4, the welding system A3 may include a mechanism capable of detecting the inclination of the cart 4 from outside the cart 4. For example, the cart 4 and the workpieces W may be imaged by a camera, and the inclination of the cart 4 relative to the workpieces W may be calculated by image processing.

[0058] In addition, since the welding system A3 can detect the degree of inclination of the trolley 4 using the inclination sensor 46 or the like, when retracting the welding wire, the feed control unit 13 may continue retracting the welding wire until it detects that the trolley 4 has reached a horizontal position based on the degree of inclination of the trolley 4.

[0059] According to this embodiment, the inclination sensor 46 detects inclination information indicating the inclination of the cart 4, and when the determination unit 14 determines that the cart 4 is inclined by a predetermined amount or more based on the inclination information, the determination unit 14 outputs a determination signal to the feed control unit 13. When the determination signal is input from the determination unit 14, the feed control unit 13 instructs the wire feeder 5 to stop feeding the welding wire. As a result, the wire feeder 5 stops feeding the welding wire. Therefore, the welding system A3 can prevent the cart 4 from falling over due to the continued feeding of the welding wire. Also, in this embodiment, the welding system A3 has a similar configuration to the welding system A1, and can achieve the same effect as the welding system A1. Furthermore, according to this embodiment, the cart 4 can be easily configured because it is simply provided with the inclination sensor 46 on a conventional cart. Also, when the inclination sensor 46 is, for example, a three-axis acceleration sensor, the control device 1 can detect the inclination of the cart 4 in the left-right direction and the front-back direction.

[0060] The submerged arc welding system according to the present invention is not limited to the above-described embodiment. The specific configurations of the components of the submerged arc welding system according to the present invention can be freely designed in various ways. [Explanation of symbols]

[0061] A1 to A3: welding system, 1: control device, 13: feed control unit, 14: judgment unit, 3: welding torch, 4: cart, 42: protrusion, 43: tip surface, 45: push button, 46: tilt sensor, 5: wire feeder

Claims

1. 1. A submerged arc welding system for performing submerged arc welding, comprising: A welding torch that projects a tip of a welding wire and welds an object to be welded; a wire feeder that feeds the welding wire; A control device for controlling the wire feeder; A carriage on which the welding torch is mounted and which moves along the weld line; A tilt detection unit that detects when the cart is tilted by a predetermined amount or more; Equipped with The control device includes a feed control unit that stops feeding of the welding wire by the wire feeder when the tilt detection unit detects tilt. Submerged arc welding system.

2. The tilt detection unit includes a contact detection unit that detects contact with the workpiece, and detects tilt when the contact detection unit detects contact, The contact detection unit is disposed on the opposite side of the welding torch with respect to the center of gravity of the carriage in a plan view.

2. The submerged arc welding system of claim 1.

3. The cart includes a protruding portion protruding from a side surface and bending downward in a vertical direction, The protrusion has a tip surface facing vertically downward, The contact detection unit is a push button and is disposed on the tip surface.

3. The submerged arc welding system of claim 2.

4. The tilt detection unit includes a tilt sensor that detects tilt information indicating a tilt of the cart, and a determination unit that determines whether the cart is tilted by a predetermined amount or more based on the tilt information.

2. The submerged arc welding system of claim 1.

5. The feed control unit causes the wire feeder to stop feeding the welding wire and then feeds the welding wire in the opposite direction.

5. A submerged arc welding system according to claim 1.

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