JP6992224B2 - Wire feeding system and welding system - Google Patents

Description

The present invention relates to a wire feeding system for feeding wires and a welding system including the wire feeding system.

In a consumable electrode type welding system that welds using the welded wire as an electrode, the welding work range is widened by connecting the wire feeder and the welding torch with a long torch cable. .. However, if the torch cable is lengthened, the feeding resistance of the welded wire increases, so that the welded wire cannot be fed smoothly. In this case, there is a problem that the arc becomes unstable. As a method of solving this problem, a configuration for feeding the welding wire is added near the tip of the feeding path of the welding wire, and the welding wire is pulled and tensioned by the configuration to feed the welding wire. The resistance is being reduced. Such a welded wire feeding system is called a push-pull feeding system.

Further, in the consumable electrode type welding system, the operator performs an inching operation of feeding the welding wire from the wire feeder to the tip of the welding torch when the welding wire is replaced. Since the operator cannot confirm how far the welding wire is fed in the feeding path, the inching button is released when the tip of the welding wire protrudes from the tip of the welding torch. In the case of a push-pull feeding system, the feeding path of the welded wire is long, so that the operator has to hold down the inching button for a long time (for example, several tens of seconds to several minutes) and wait. Further, if the timing of releasing the inching button is delayed, the welding wire comes out too much from the tip of the welding torch, so that the operator needs to cut the excess welding wire with pliers or the like.

In order to eliminate the burden on these workers, a method of detecting the arrival of the weld wire and automatically stopping the wire has been proposed. For example, Patent Document 1 discloses a method of electrically detecting that a welding wire has come into contact with a contact tip at the tip of a welding torch. Further, Patent Document 2 discloses a method of detecting the arrival of a welded wire by using a non-contact sensor.

Jitsukaihei 5-13669 Gazette Japanese Unexamined Patent Publication No. 2017-24043

However, in the case of these methods, it is necessary to add a new detection mechanism in order to detect the arrival of the weld wire. The addition of new detection mechanisms complicates the structure of the weld torch or weld power supply and increases manufacturing costs. It should be noted that a method of calculating the feed amount of the welded wire from the rotation speed of the feed motor and stopping the feed when the predetermined feed amount is reached is also conceivable. However, if the predetermined feed amount that differs depending on the length of the torch cable is set incorrectly, or if the feed amount calculation is started from the state where the weld wire has advanced halfway through the feed path, the weld wire will be the weld torch. A large amount will pop out from the tip of the torch. Therefore, in the case of this method, it is necessary to add a detection mechanism for preventing the pop-out. The need for a new detection mechanism to detect the arrival of a wire in the inching operation is also a problem in systems other than welding systems. For example, in a thermal spraying system, the same problem arises when the thermal spray wire is fed to the thermal spray gun, and in a brazing system, when the brazing wire is fed.

The present invention has been conceived under the above circumstances, and includes a wire feeding system capable of detecting the arrival of a wire without adding a new detection mechanism, and the wire feeding system. Its purpose is to provide a welding system.

In order to solve the above problems, the following technical means are taken in the present invention.

The wire feeding system provided by the first aspect of the present invention is arranged in a first feeding section for feeding the wire and a feeding direction side of the wire from the first feeding section, and is a feeding motor. The control unit includes a second feeding unit that feeds the wire by rotation of the feeding motor, and a control unit that controls the first feeding unit and the second feeding unit. The wire reaches the second feeding unit based on an electric signal supplied to the feeding motor, a sensor that detects the rotational speed of the feeding motor, and a detection value detected by the sensor. It is characterized by including a arrival detection unit for detecting the fact. According to this configuration, the wire is first fed by the first feeding section, and after the wire reaches the second feeding section, it is fed by the first feeding section and the second feeding section. The feeding motor of the second feeding section is in a no-load state until the wire reaches the second feeding section, but is loaded after the wire reaches the second feeding section. Therefore, before and after the wire reaches the second feeding unit, the electrical signal output to the feeding motor changes. The arrival detection unit detects that the wire has reached the second feeding unit from the change of the electric signal output to the feeding motor based on the detection value detected by the sensor. The wire feeding system is equipped with a sensor that detects an electrical signal output to the feeding motor in order to detect an abnormality. Since the arrival of the wire is detected using the sensor, there is no need to add a new detection mechanism.

The "electrical signal" includes current, electric power, voltage and the like. Further, the "sensor that detects the electric signal supplied to the feed motor" is not limited to the sensor that detects the electric signal on the connection line connecting the drive circuit and the feed motor, and is not limited to, for example, the drive circuit and the power supply. It also includes a sensor that detects an electrical signal supplied to a feed motor by detecting an electrical signal on a connection line connecting to and.

The wire feeding system provided by the second aspect of the present invention is a first feeding unit having a feeding motor and feeding wires by rotation of the feeding motor, and the first feeding unit. A second feeding unit, which is arranged on the feeding direction side of the wire and feeds the wire, and a control unit that controls the first feeding unit and the second feeding unit, are provided. It includes a sensor that detects an electric signal supplied to the feed motor, and a reach detection unit that detects that the wire has reached the second feed unit based on the detection value detected by the sensor. It is characterized by that. According to this configuration, the wire is first fed by the first feeding section, and after the wire reaches the second feeding section, it is fed by the first feeding section and the second feeding section. The feeding motor of the first feeding section is heavily loaded until the wire reaches the second feeding section, but the load is reduced after the wire reaches the second feeding section. Therefore, before and after the wire reaches the second feeding unit, the electrical signal output to the feeding motor changes. The arrival detection unit detects that the wire has reached the second feeding unit from the change of the electric signal output to the feeding motor based on the detection value detected by the sensor. The wire feeding system is equipped with a sensor that detects an electrical signal output to the feeding motor in order to detect an abnormality. Since the arrival of the wire is detected using the sensor, there is no need to add a new detection mechanism.

In a preferred embodiment of the present invention, the arrival detection unit includes a comparison unit that compares the detected value with a threshold value, and detects the arrival of the wire based on the comparison result in the comparison unit. According to this configuration, the arrival of the wire can be detected when the detection value exceeds the threshold value.

In a preferred embodiment of the present invention, the arrival detection unit includes a calculation unit for calculating a differential value of the detected value and a comparison unit for comparing the differential value with a threshold value, and the comparison result in the comparison unit. The arrival of the wire is detected based on the above. According to this configuration, the arrival of the wire can be detected based on the change in the rate of increase of the detected value.

In a preferred embodiment of the present invention, the arrival detection unit changes the threshold value according to a command value of the feeding speed of the wire. According to this configuration, even when the detected value in the no-load state of the feeding motor changes depending on the feeding speed of the wire, it is possible to suppress the false detection of the arrival of the wire.

In a preferred embodiment of the invention, the electrical signal is an electric current. According to this configuration, the arrival of a wire can be detected based on the change in current.

In a preferred embodiment of the present invention, the control unit stops the first feeding unit and the second feeding unit when the arrival detecting unit detects the arrival of the wire. According to this configuration, the feeding of the wire can be automatically stopped when the second feeding unit is reached.

In a preferred embodiment of the present invention, the control unit may feed the wire by the first feeding unit and the second feeding unit when the arrival detecting unit detects the arrival of the wire. When a predetermined low-speed feeding time elapses after the feeding speed is lowered, the first feeding unit and the second feeding unit are stopped. According to this configuration, the wire feeding can be automatically stopped when the low speed feeding time elapses after reaching the second feeding unit. If the low-speed feeding time is set appropriately, it is possible to feed the wire to the tip of the welding torch and then stop it.

In a preferred embodiment of the present invention, when the arrival detection unit detects the arrival of the wire, the notification unit for notifying the arrival of the wire is further provided. According to this configuration, the operator can be notified of the arrival of the wire.

In a preferred embodiment of the present invention, the control unit integrates a speed detection unit that detects the feeding speed of the wire by the first feeding unit and the feeding speed detected by the speed detecting unit. Then, even if the feed amount calculation unit that calculates the feed amount from the start of feed of the wire and the feed amount calculated by the feed amount calculation unit become the first predetermined value or more, the arrival detection unit Further includes an abnormality detecting unit for detecting an abnormality when the wire does not detect the arrival of the wire. According to this configuration, it is possible to detect an abnormality such as a wire buckling or a first feeding unit.

In a preferred embodiment of the present invention, the control unit integrates the speed detection unit for detecting the feeding speed of the wire by the first feeding unit and the speed detected by the speed detecting unit. When the feed amount calculation unit that calculates the feed amount from the start of feed of the wire and the feed amount calculated by the feed amount calculation unit are equal to or less than the second predetermined value, the arrival detection unit performs the wire. It is further provided with an abnormality detection unit that detects an abnormality when the arrival of the wire is detected. According to this configuration, it is possible to detect an abnormality in the second feeding unit or the like.

The welding system provided by the second aspect of the invention is provided by a welding torch, a welding power supply that supplies power to the welding torch, and a first aspect of the invention that feeds wires to the welding torch. It is characterized by having a wire feeding system provided.

In a preferred embodiment of the present invention, the second feeding unit is arranged on the welding torch. According to this configuration, the position where the arrival of the wire is detected can be set closer to the tip of the welding torch.

According to the present invention, the wire is first fed by the first feeding section, and after the wire reaches the second feeding section, it is fed by the first feeding section and the second feeding section. The feeding motor of the second feeding section is in a no-load state until the wire reaches the second feeding section, but is loaded after the wire reaches the second feeding section. Therefore, before and after the wire reaches the second feeding unit, the electrical signal output to the feeding motor changes. The arrival detection unit detects that the wire has reached the second feeding unit from the change of the electric signal output to the feeding motor based on the detection value detected by the sensor. The wire feeding system is equipped with a sensor that detects an electrical signal output to the feeding motor in order to detect an abnormality. Since the arrival of the wire is detected using the sensor, there is no need to add a new detection mechanism.

Other features and advantages of the invention will be more apparent by the detailed description given below with reference to the accompanying drawings.

It is a schematic diagram which shows the whole structure of the welding system which concerns on 1st Embodiment. It is a block diagram which shows the functional structure of the welding system shown in FIG. It is a timing chart for demonstrating the automatic stop of feeding of a welding wire. It is a flowchart for demonstrating the inching process in the welding system which concerns on 1st Embodiment, (a) shows the inching control process performed by the control part of a welding power supply device, (b) is the arrival performed by the control part of a welding torch. Indicates the detection process. It is a flowchart for demonstrating the inching process in the modification. It is a timing chart for demonstrating the automatic stop of feeding of a welding wire in a modification. It is a block diagram which shows the functional structure of the welding system which concerns on 2nd Embodiment. It is a block diagram which shows the functional structure of the welding system which concerns on 3rd Embodiment. It is a timing chart for demonstrating the automatic stop of feeding of a welding wire in 3rd Embodiment. It is a schematic diagram which shows the whole structure of the welding system which concerns on 4th Embodiment. It is a block diagram which shows the functional structure of the welding system shown in FIG.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

[First Embodiment]
1 to 2 are diagrams for explaining the welding system A1 according to the first embodiment. FIG. 1 is a schematic diagram showing the overall configuration of the welding system A1. FIG. 2 is a block diagram showing a functional configuration of the welding system A1.

As shown in FIG. 1, the welding system A1 includes a welding power supply device 1, a wire feeding device 2, a welding torch 3, a power cable 41, 42, a power transmission line 5, a gas cylinder 6, a gas pipe 7, a communication line 8, and a welding line 8. It is equipped with a torch cable 39. The welding power supply device 1 and the wire feeding device 2 are connected by a power cable 41, a power transmission line 5, and a communication line 8. Further, the wire feeding device 2 and the welding torch 3 are connected by a torch cable 39. The torch cable 39 has a power cable 41, a gas pipe 7, a liner, a power transmission line, and a communication line arranged inside the cable. The length of the torch cable 39 is, for example, about a dozen meters. The liner arranged on the torch cable 39 is a part of the feeding path of the welding wire B, and since the torch cable 39 is long, the feeding path is also long. The power cable 41, gas pipe 7, liner, power transmission line and communication line inside the torch cable 39 are the power cable 41, gas pipe 7, liner, power transmission line 5 and communication inside the wire feeder 2, respectively. Connected to wire 8.

One output terminal of the welding power supply device 1 is connected to the welding torch 3 via a power cable 41. The wire feeding device 2 sends the welding wire B to the welding torch 3 so that the tip of the welding wire B protrudes from the tip of the welding torch 3. In a contact tip (not shown) arranged at the tip of the welding torch 3, the power cable 41 and the welding wire B are electrically connected. The other output terminal of the welding power supply device 1 is connected to the workpiece W via the power cable 42. The welding power supply device 1 generates an arc between the tip of the welding wire B protruding from the tip of the welding torch 3 and the workpiece W, and supplies electric power to the arc. The welding system A1 welds the workpiece W with the heat of the arc.

Further, in the present embodiment, as shown in FIG. 2, the welding torch 3 includes a feeding unit 31 which is configured to feed the welding wire B. That is, in the feeding path of the welding wire B, two feeding sections 21 (wire feeding device 2) and a feeding section 31 (welding torch 3) are arranged as a configuration for feeding the welding wire B. ing. The feeding unit 21 (wire feeding device 2) feeds the welding wire B in the feeding direction (direction in which the welding wire B advances) (push side feeding unit). Further, the feeding unit 31 (welding torch 3) is arranged on the feeding direction side from the feeding unit 21 (wire feeding device 2), and pulls the welded wire B in the feeding direction (pull side feeding unit). .. That is, the feeding unit 21 (wire feeding device 2) and the feeding unit 31 (welding torch 3) form a push-pull type wire feeding system. It can be considered that the welding torch 3 includes the feeding unit 31, or that the feeding unit 31, which is a part of the wire feeding system, is arranged in the welding torch 3. can.

Electric power (for example, 24V DC) for driving the feeding motor 211 and the like is supplied from the welding power supply device 1 to the wire feeding device 2 via the power transmission line 5. Further, the electric power supplied from the welding power supply device 1 is also supplied from the wire feeding device 2 to the welding torch 3 via a power transmission line (not shown) provided inside the torch cable 39. The welding torch 3 may be directly supplied with electric power from the welding power supply device 1. Further, the wire feeding device 2 and the welding torch 3 may be supplied with electric power from other than the welding power supply device 1.

The welding power supply device 1 and the wire feeding device 2 communicate with each other via the communication line 8. Further, the wire feeding device 2 and the welding torch 3 communicate with each other via a communication line (not shown) provided inside the torch cable 39. The welding torch 3 and the welding power supply device 1 communicate with each other by mediating the wire feeding device 2. The welding torch 3 and the welding power supply device 1 may directly communicate with each other. Further, the communication method is not limited, and may be power line carrier communication using a power transmission line or power cables 41, 42, or may be wireless communication. Further, information may be transmitted between the welding power supply device 1, the wire feeding device 2, and the welding torch 3 by means of a voltage or current level or a pulse via a control line.

The welding system A1 uses a shield gas during welding. The shield gas of the gas cylinder 6 is supplied to the tip of the welding torch 3 by a gas pipe 7 provided so as to pass through the wire feeding device 2. The welding system A1 may circulate cooling water in the welding torch 3.

The welding power supply device 1 supplies electric power for arc welding to the welding torch 3. The welding power supply device 1 converts the three-phase AC power input from the power system P into power suitable for arc welding and outputs it. Further, the welding power supply device 1 converts the three-phase AC power input from the power system P into DC power for driving the feed motor 311 of the wire feed device 2, and passes through the power transmission line 5. Is output to the wire feeding device 2.

As shown in FIG. 2, the welding power supply device 1 includes a control unit 11. The control unit 11 is realized by, for example, a microcomputer or the like, and controls the welding power supply device 1. The control unit 11 controls an inverter circuit (not shown) so as to output electric power according to the set welding conditions. Further, the control unit 11 controls the feeding unit 21 and the feeding unit 31 via the control unit 22 of the wire feeding device 2 and the control unit 32 of the welding torch 3, thereby welding at the time of welding and inching. Controls the feeding of wire B. Specifically, the control unit 11 transmits a speed command S ₁ for instructing the feeding speed of the welded wire B to the control unit 22 of the wire feeding device 2. Further, the control unit 11 transmits a speed command S ₂ for instructing the feeding speed of the welding wire B to the control unit 32 of the welding torch 3. _The control unit 22 controls the feeding unit 21 based on the received speed command S1. Further, the control unit 32 controls the feeding unit 31 based _on the received speed command S2. _The control unit ₁₁ transmits the speed commands S1 and S2 so that the feeding speed by the feeding unit 31 is several percent higher than the feeding speed by the feeding unit 21. Since the feeding speed by the feeding unit 31 (pull side feeding unit) is higher than the feeding speed by the feeding unit 21 (push side feeding unit), tension is applied to the weld wire B. As a result, the feeding resistance of the welding wire B is suppressed, and buckling of the welding wire B is prevented. The details of the control for inching the welding wire B performed by the control unit 11 will be described later.

The wire feeding device 2 feeds the welding wire B to the welding torch 3. As shown in FIG. 2, the wire feeding device 2 includes a feeding unit 21 and a control unit 22.

The feeding unit 21 is driven by a driving signal input from the control unit 22 to send out the welding wire B. The feeding unit 21 includes a feeding motor 211, a feeding roll 212, and a pressurizing roll 213.

The feed motor 211 generates a driving force for feeding the welding wire B. The feed motor 211 is driven by a drive signal input from the control unit 22 (drive unit 221 described later). The feed motor 211 is, for example, a brushless motor, and the rotation speed is controlled by adjusting the drive signal. The control unit 22 (drive unit 221 described later) controls the rotation speed of the feed motor 211 by adjusting the pulse width of the drive signal, for example, by pulse width modulation or the like.

The feed roll 212 is attached to the rotating shaft of the feed motor 211, and the torque generated by the feed motor 211 is transmitted to rotate the feed roll 212. The feeding roll 212 is not limited to the one directly attached to the rotating shaft of the feeding motor 211. The torque of the feed motor 211 may be transmitted to the feed roll 212 by one or more gears to rotate the feed roll 212. The welding wire B is in contact with the feed roll 212, and the torque of the feed motor 211 is converted into a tangential force that feeds the weld wire B. Therefore, the welding wire B is fed by driving the feed motor 211.

The pressurizing roll 213 is arranged so as to face the feeding roll 212 with the welding wire B interposed therebetween, and pressurizes the welding wire B to the feeding roll 212 side. As a result, the welding wire B is fed according to the rotation of the feed roll 212.

The control unit 22 is realized by, for example, a microcomputer or the like, and controls the wire feeding device 2. The control unit 22 feeds the welding wire B by driving the feeding unit 21 based on a command from the control unit 11 of the welding power supply device 1, and also opens a gas solenoid valve (not shown). , Supply the shield gas to the welding torch 3. As shown in FIG. 2, the control unit 22 includes a drive unit 221.

The drive unit 221 controls the drive of the feed unit 21 to control the feed of the welding wire B. The drive unit 221 outputs a drive signal to the feed motor 211 of the feed unit 21 based on the speed command S1 received from the control unit 11 of the welding power supply device ₁ . An encoder (not shown) is attached to the feed motor 211, and the control unit 22 detects the rotation speed of the feed motor 211 from the pulse signal input from the encoder. The encoder may be an optical encoder or a magnetic encoder. The drive unit 221 adjusts the drive signal so that the detected rotation speed of the feed motor 211 matches the rotation speed according to the speed command S ₁ , and performs feedback control. The method for detecting the rotation speed is not limited.

The wire feeding device 2 includes a cylindrical guide member such as an inlet liner, an inlet guide, and an outlet guide, but the illustration is omitted. The inlet liner and inlet guide guide the weld wire B from the wire reel 23 around which the weld wire B is wound to the feed roll 212. The outlet guide guides the welding wire B sent out by the feeding roll 212 to the feeding port of the wire feeding device 2. The welding wire B sent out from the wire feeding device 2 is guided to the tip of the welding torch 3 through the inside of the liner provided inside the torch cable 39 and the welding torch 3. Guide members such as an inlet liner, an inlet guide, and an outlet guide, and a liner provided inside the torch cable 39 and the welding torch 3 form a feeding path for the welding wire B.

The welding torch 3 welds the workpiece W by the welding electric power supplied from the welding power supply device 1. Further, the welding torch 3 has a configuration for feeding the welding wire B, and by pulling the welding wire B and applying tension, the feeding resistance of the welding wire B is reduced. As shown in FIG. 2, the welding torch 3 includes a feeding unit 31, a control unit 32, an operating unit 33, and a display unit 34.

The feeding unit 31 is driven by a drive signal input from the control unit 32 to pull the welding wire B. The feeding unit 31 includes a feeding motor 311, a feeding roll 312, and a pressurizing roll 313.

The feed motor 311 generates a driving force for feeding the welding wire B. The feed motor 311 is driven by a drive signal input from the control unit 32 (drive unit 321 described later). The feed motor 311 is, for example, a brushless motor, and the rotation speed is controlled by adjusting the drive signal. The control unit 32 (drive unit 321 described later) controls the rotation speed of the feed motor 311 by adjusting the pulse width of the drive signal, for example, by pulse width modulation or the like.

The feed roll 312 is attached to the rotating shaft of the feed motor 311 and rotates by transmitting the torque generated by the feed motor 311. The method of transmitting the torque of the feed motor 311 to the feed roll 312 is not limited. The welding wire B is in contact with the feed roll 312, and the torque of the feed roll 312 is converted into a tangential force for pulling the weld wire B. Therefore, the welding wire B is towed by driving the feed motor 311.

The pressurizing roll 313 is arranged so as to face the feeding roll 312 with the welding wire B interposed therebetween, and pressurizes the welding wire B to the feeding roll 312 side. As a result, the welding wire B is fed according to the rotation of the feed roll 312.

The control unit 32 is realized by, for example, a microcomputer or the like, and controls the welding torch 3. The control unit 32 performs predetermined processing according to the operation signal input from the operation unit 33. Further, the control unit 32 communicates with the welding power supply device 1 and the wire feeding device 2, writes and reads information in a storage unit (not shown), receives an operation signal from the operation unit 33 and performs corresponding processing, and a display unit 34. Control the display etc. in. Further, the control unit 32 feeds the welding wire B by driving the feeding unit 31 based on a command from the control unit 11 of the welding power supply device 1. As shown in FIG. 2, the control unit 32 includes a drive unit 321, a current sensor 322, and a reach detection unit 323.

The drive unit 321 controls the drive of the feed unit 31 to control the feed of the welding wire B. The drive unit 321 outputs a drive signal to the feed motor 311 of the feed unit 31 based on the speed command S ₂ received from the control unit 11 of the welding power supply device 1. An encoder (not shown) is attached to the feed motor 311, and the control unit 32 detects the rotation speed of the feed motor 311 from the pulse signal input from the encoder. The encoder may be an optical encoder or a magnetic encoder. The drive unit 321 adjusts the drive signal so that the detected rotation speed of the feed motor 311 _matches the rotation speed according to the speed command S2, and performs feedback control. The method for detecting the rotation speed is not limited.

The current sensor 322 is a sensor that detects the current value of the drive signal output from the drive unit 321 to the feed motor 311. The control unit 32 has an overcurrent protection function for protecting the feed motor 311 and the like from overcurrent based on the current detection value I ₂ detected by the current sensor 322. Further, the current detection value I ₂ detected by the current sensor 322 is also output to the arrival detection unit 323.

The arrival detection unit 323 detects that the welding wire B has reached the feeding unit 31 based on the current detection value I ₂ input from the current sensor 322. The welding wire B is first fed by the feeding section 21 of the wire feeding device 2, and after the welding wire B reaches the feeding section 31 of the welding torch 3, it is fed by the feeding section 21 and the feeding section 31. Will be sent. The feeding motor 311 of the feeding section 31 is in a no-load state until the welding wire B reaches the feeding section 31, but the welding wire B reaches the feeding section 31 (strictly speaking, the feeding roll 312). After that, the load is applied. Therefore, before and after the welding wire B reaches the feeding unit 31, the current value of the drive signal output from the driving unit 321 to the feeding motor 311 changes. The arrival detection unit 323 has reached the welding wire B from the change in the current value of the drive signal output to the feeding motor 311 based on the current detection value I ₂ input from the current sensor 322. Detect that. Specifically, the arrival detection unit 323 compares the current detection value I ₂ input from the current sensor 322 with the current threshold value I _2th , and when the current detection value I ₂ becomes the current threshold value I _2th or more, It is determined that the welding wire B has reached the feeding unit 31. The current threshold I _2th is the current detection value I _2L when the feeding motor 311 is in a no-load state (before the welding wire B reaches the feeding unit 31) and when the feeding motor 311 is loaded (before the welding wire B reaches the feeding unit 31). It is set as a value between the current detection value I _2H of the feeding unit 31 (when the welding wire B is fed).

In the present embodiment, the current detection value I _2L in the no-load state is about 0.3A, and the current detection value I _2H in the no-load state is about 0.6A, so that the current threshold value I _2th is set. It is set to 0.45A. The current threshold value I _2th is not limited. The closer the current threshold value I _2th is to the current detection value I _2L , the faster the arrival of the weld wire B can be detected, but the possibility of erroneous detection of arrival increases. On the other hand, the closer the current threshold value I _2th is to the current detection value I _2H , the more the false detection of arrival can be suppressed, but the timing of detecting the arrival is delayed. The current threshold value I _2th may be appropriately set between the current detection value I _2L and the current detection value I _2H .

When the arrival detection unit 323 detects that the welding wire B has reached the feeding unit 31, it generates a arrival detection signal. The arrival detection signal is transmitted to the welding power supply device 1.

The display unit 34 displays various types of displays, and includes, for example, a display (not shown) which is a liquid crystal display device. The display unit 34 is controlled by the control unit 32 and displays various information. The display unit 34 corresponds to the "notification unit" of the present invention.

The operation unit 33 includes a plurality of operation means, and outputs the operation of each operation means by the operator to the control unit 32 as an operation signal. The operating means include a torch switch, an inching button and an operating button (not shown). The operation unit 33 may be provided with other operation means.

The torch switch is an operating means for accepting a welding start / stop operation. When the torch switch is turned on (pressed), an operation signal is output to the control unit 32. The control unit 32 to which the operation signal is input generates a signal instructing the start of welding and transmits it to the welding power supply device 1. Upon receiving the signal, the welding power supply device 1 starts feeding the welding wire B and also starts outputting welding power. Further, when the on operation is canceled, the operation signal is output to the control unit 32. The control unit 32 to which the operation signal is input generates a signal instructing the end of welding and transmits it to the welding power supply device 1. Upon receiving the signal, the welding power supply device 1 stops the feeding of the welding wire B and also stops the output of the welding power. As a result, welding is performed only while the torch switch is pressed. The transmission of the on / off operation of the torch switch may be performed by changing the level of the electric signal via the control line.

The inching button is an operation means for accepting a start / stop operation of an inching operation. By turning on (pressing) the inching button, an operation signal is output to the control unit 32. The control unit 32 to which the operation signal is input generates a signal instructing the start of inching and transmits it to the welding power supply device 1. Upon receiving the signal, the welding power supply device 1 starts feeding the welding wire B. Further, when the on operation is canceled, the operation signal is output to the control unit 32. The control unit 32 to which the operation signal is input generates a signal instructing the end of inching and transmits it to the welding power supply device 1. Upon receiving the signal, the welding power supply device 1 stops feeding the welding wire B. As a result, the welding wire B is fed only while the inching button is pressed. The operation method of the inching button is not limited. Each time the inching button is pressed, it may be set to switch between feeding and stopping feeding of the welding wire B. The on / off operation of the inching button may be transmitted by changing the level of the electric signal via the control line. Further, the inching button may be provided in the welding power supply device 1 or the wire feeding device 2. In the present embodiment, even if the feeding stop of the welding wire B is not instructed, when the welding wire B reaches the feeding section 31 of the welding torch 3, the feeding of the welding wire B is stopped. Details of inching will be described later.

The operation buttons are operation means for switching screens and changing various setting values. The operation buttons include, for example, an up button, a down button, a left button, and a right button. When each button is pressed, the corresponding operation signal is output to the control unit 32, and the control unit 32 performs the corresponding process. For example, when the left or right button is pressed, the mode is switched and the screen displayed on the display is switched, and when the up or down button is pressed, the setting value displayed on the display is changed. To. In the present embodiment, the operation of the inching button can be accepted when the "inching mode" is switched by the operation of the left button or the right button. The inching operation may be set to be performed by operating an operation button (for example, a left button or a right button). In this case, it is not necessary to provide an inching button.

In the present embodiment, the feeding unit 21 corresponds to the "first feeding unit" of the present invention, and the feeding unit 31 corresponds to the "second feeding unit" of the present invention. Further, the control unit 11, the control unit 22, and the control unit 32 correspond to the "control unit" of the present invention.

Next, inching will be described.

The inching is performed, for example, as a preparatory work after attaching a new wire reel 23 to the wire feeding device 2. The operator manually inserts the tip of the welding wire B pulled out from the wire reel 23 into the inlet liner and the inlet guide of the wire feeding device 2 and guides the welding wire B to the feeding roll 212.

Then, the operator presses the inching button of the welding torch 3. Upon pressing the inching button, the welding power supply device 1 starts feeding the welding wire B. Specifically, the welding power supply device 1 (control unit 11) transmits the speed command S ₁ to the control unit 22 of the wire feeding device 2 and transmits the speed command S ₂ to the control unit 32 of the welding torch 3. The control unit 22 (drive unit 221) controls the rotation speed of the feed motor 211 based _on the received speed command S1. As a result, the welding wire B is fed at _a speed according to the speed command S1. Further, the control unit 32 (drive unit 321) controls the rotation speed of the feed motor 311 based _on the received speed command S2.

The welding power supply device 1 (control unit 11) gradually increases the speed command S ₁ from "0" to obtain the set speed command S _1H . Further, the speed command S ₂ is gradually increased from "0" to obtain the set speed command S _2H . _The speed commands S1 and S2 _are gradually increased in order to suppress the overshoot of the current value of the drive signal generated by the rapid increase. If overshoot is not a problem, the speed command S ₁ (S ₂ ) may be switched from "0" to S _1H (S _2H ).

When stopping the inching, the operator releases the pressing of the inching button of the welding torch 3. In response to the release of the inching button, the welding power supply device 1 stops feeding the welding wire B. Specifically, the welding power supply device 1 (control unit 11) issues a speed command S ₁ transmitted to the control unit 22 of the wire feeding device 2 and a speed command S ₂ transmitted to the control unit 32 of the welding torch 3. Gradually decrease to "0". As a result, the feeding of the welding wire B is stopped. The speed command S ₁ (S ₂ ) may be switched from S _1H (S _2H ) to “0”.

In the present embodiment, even if the operator does not instruct to stop the feeding of the welding wire B, when the welding wire B reaches the feeding portion 31 of the welding torch 3, the feeding of the welding wire B is stopped. The automatic stop of the feeding will be described below with reference to FIG.

FIG. 3 is a timing chart for explaining the automatic stop of feeding of the welding wire B. FIG. 3A shows the time change of the speed command S1 transmitted from the welding power supply device ₁ to the wire feeding device 2, and FIG. 3B shows the transmission from the welding power supply device 1 to the welding torch 3. It shows the _time change of the speed command S2 to be performed. FIG. 3C shows the time change of the current detection value I ₂ detected by the current sensor 322. FIG. 3D shows a arrival detection signal transmitted by the arrival detection unit 323. FIG. 3 (e) shows the time change of the tension applied to the welding wire B. FIG. 3 (f) shows the time change of the feed amount of the welding wire B.

_When the _inching is started at time t0, the speed commands S1 and S2 gradually increase. Then, the speed command S ₁ becomes the set speed command S _1H , and the speed command S ₂ becomes the set speed command S _2H (see FIGS. 3A and 3B). At the start of feeding, an overshoot occurs in the current value of the drive signal output by the driving unit 321 to the feeding motor 311, and the current detection value I ₂ becomes the current threshold value I _2th or higher (see FIG. 3C). ). Therefore, the arrival detection unit 323 does not perform detection until the predetermined time T1 elapses from the start of feeding (between the time t0 and the predetermined time t4). Then, the welding wire B is fed at a constant speed, and the feed amount increases (see FIG. 3 (f)). At this time, since the welding wire B has not yet reached the feeding unit 31 (feeding roll 312), the feeding motor 311 is idling and is in a no-load state. Therefore, the current detection value I ₂ is the current detection value I _2L in the no-load state (see FIG. 3C).

Then, when the feed amount of the weld wire B reaches L1 at time t1 (see FIG. 3 (f)), when the tip of the weld wire B reaches the feed unit 31 (feed roll 312), the feed is fed. Tension is gradually applied to the welding wire B that has been slightly bent in the path (see FIG. 3 (e)). Since the feed motor 311 is loaded accordingly, the current detection value I ₂ increases (see FIG. 3 (c)).

When the current detection value I ₂ becomes the current threshold I _2th or more at time t2 (see FIG. 3C), the arrival detection unit 323 detects that the welding wire B has reached the feeding unit 31 and detects arrival. A signal is transmitted to the welding power supply device 1 (see FIG. 3D). Upon receiving the arrival detection signal, the welding power supply device ₁ reduces the speed commands S1 and S2 to " ₀ " (see FIGS. 3A and 3B). As a result, the feeding motor 211 and the feeding motor 311 are stopped, and the feeding of the welding wire B is stopped (see FIG. 3 (f)). At this time, the tension applied to the welding wire B decreases to "0" (see FIG. 3 (e)), and the current detection value I ₂ decreases accordingly to "0" (FIG. 3 (c)). )reference). The feeding of the welding wire B is continued from the time when the tip of the welding wire B reaches the feeding roll 312 (time t1) to the time when the arrival detection unit 323 detects the arrival (time t2). However, this time (t2-t1) is sufficiently smaller than the total feeding time, and the feeding amount of the welding wire B fed in this time is very small (for example, about several cm).

When the feeding of the welding wire B is automatically stopped, the control unit 32 of the welding torch 3 displays on the display of the display unit 34 that the welding wire B has been automatically stopped. The worker can know that the automatic stop has occurred by looking at the display. The method of notifying the operator of the automatic stop is not limited. It may be notified by a voice from a speaker (not shown) or by turning on a lamp (not shown). Further, it may be notified by vibrating the welding torch 3. The control unit 32 may detect the automatic stop by the arrival detection signal output by the arrival detection unit 323, or automatically by the communication signal ₍ speed command S2 or the signal notifying the automatic stop) from the welding power supply device 1. A stop may be detected.

After the automatic stop, the operator feeds the welding wire B from the feeding unit 31 to the tip of the welding torch 3 by operating the inching button. At this time, the control unit 11 of the welding power supply device 1 sets the speed command S ₁ as the speed command S _1L whose feeding speed is slower than the speed command S _1H , and sets the speed command S ₂ as the feeding speed slower than the speed command S _2H . The speed command is S _2L . In this embodiment, the speed command S _1H is set to the speed at which the welding wire B is fed about 15 to 20 m per minute, and the speed command S _1L is set to the speed at which the welding wire B is fed about several meters per minute. The speed command S _2H (S _2L ) is set to a speed several percent higher than the speed command S _1H (S _1L ). The speed commands S _1H , S _1L , S _2H , and S _2L are not limited. Since the distance from the feeding unit 31 to the tip of the welding torch 3 is short (for example, about several tens of cm), the increase in the required time is small even if the feeding speed is slowed down. On the other hand, since the feeding speed becomes slow, the operator can easily stop the feeding at an appropriate timing. _The control unit ₁₁ does not automatically change the speed commands S1 and S2, but the operator changes the speed commands _S1 and S2 by operating the operation unit 33 of the welding torch ₃ . May be good. Further, the speed command S ₁ (S ₂ ) may be left as the speed command S _1H (S ₂ ).

FIG. 4 is a flowchart for explaining the inching process in the welding system A1. FIG. 4A shows the inching control process performed by the control unit 11 of the welding power supply device 1, and FIG. 4B shows the arrival detection process performed by the control unit 32 of the welding torch 3.

The inching control process shown in FIG. 4A is started when the welding power supply device 1 is started. The process may be executed only when the welding torch 3 is switched to the "inching mode". First, the control unit 11 determines whether or not the inching start is instructed (S1). Specifically, the control unit 11 determines whether or not a signal instructing the start of inching has been received from the control unit 32 of the welding torch 3. If the start of inching is not instructed (S1: NO), the process returns to step S1 and the determination is repeated. That is, the control unit 11 waits until the start of inching is instructed. When the start of inching is instructed (S1: YES), the control unit 11 instructs the start of feeding of the welding wire B (S2). Specifically, the control unit 11 transmits the speed command S 1 to the wire feeding device 2 while increasing the speed command S ₁ from “0” to S _1H . Further, the speed command S ₂ is transmitted to the welding torch 3 while increasing from “0” to S _2H .

Next, the control unit 11 determines whether or not the inching end is instructed (S3). Specifically, the control unit 11 determines whether or not a signal instructing the end of inching has been received from the control unit 32 of the welding torch 3. When the end of inching is not instructed (S3: NO), the control unit 11 determines whether or not a arrival detection signal has been received from the control unit 32 of the welding torch 3 (S4). When the arrival detection signal is not received (S4: NO), the process returns to step S3, and the determination of step S3 and step S4 is repeated. That is, the control unit 11 waits until the end of inching is instructed or the arrival detection signal is received. When the end of inching is instructed (S3: YES) or the arrival detection signal is received (S4: YES), the control unit 11 instructs to stop the feeding of the welding wire B (S5). Specifically, the control unit 11 transmits the speed command S 1 to the wire feeding device 2 while reducing the speed command S ₁ from S _1H to “0”. Further, the speed command S ₂ is transmitted to the welding torch 3 while decreasing from S _2H to “0”. Then, the process returns to step S1, and the control unit 11 waits until the inching start is instructed.

The arrival detection process shown in FIG. 4B is started when the welding torch 3 is activated. The control process may be executed only when the mode is switched to the "inching mode". _First , the control unit 32 determines whether or not the speed command S1 has been received from the control unit 11 (S11). If it is not received (S11: NO), the process returns to step S11 and the determination is repeated. That is, the control unit 32 waits until the speed command _S1 is received. Upon receiving the speed command S ₁ (S11: YES), the control unit 32 waits for the predetermined time T1 to elapse (S12). Since the arrival detection unit 323 erroneously detects the arrival of the welding wire B due to the overshoot of the current value of the drive signal generated at the start of feeding, the arrival detection unit 323 should not perform detection until the overshoot converges. I have to. During this time, the control unit 32 increases the rotation speed of the feed motor 311 in response to the speed command S1 received from the control unit ₁₁ .

After the elapse of the predetermined time T1 (S12: YES), the control unit 32 detects the current value of the drive signal input to the feed motor 311 (S13). Specifically, the control unit 32 acquires the current detection value I ₂ detected by the current sensor 322 and inputs it to the arrival detection unit 323. Next, the arrival detection unit 323 compares the current detection value I ₂ with the current threshold value I _2th (S14). When the current detection value I ₂ is less than the current threshold value I _2th (S14: NO), the process returns to S13. On the other hand, when the current detection value I ₂ is the current threshold value I _2th or more (S14: YES), the arrival detection unit 323 generates the arrival detection signal. The control unit 32 transmits a arrival detection signal to the welding power supply device 1 (S15). Next, the control unit 32 waits for the predetermined time T2 to elapse (S16). During this time, the control unit 32 reduces the rotational speed of the feed motor 311 and stops the feed motor 311 in response to the speed command S1 received from the control unit ₁₁ . Then, the process returns to S11, and the control unit 32 waits for the reception of the speed command _S1 .

The processing shown in each flowchart of FIG. 4 is an example, and the inching control processing performed by the control unit 11 and the arrival detection processing performed by the control unit 32 are not limited to those described above.

Next, the operation and effect of the welding system A1 will be described.

According to the present embodiment, the arrival detection unit 323 determines that the welding wire B has reached the feeding unit 31 when the current detection value I ₂ input from the current sensor 322 becomes the current threshold I _2th or more. Then, the arrival detection signal is transmitted to the welding power supply device 1. When the control unit 11 of the welding power supply device ₁ receives the arrival detection signal, the speed commands S1 and S2 _are reduced to "0". As a result, the feeding motor 211 and the feeding motor 311 are stopped, and the feeding of the welding wire B is stopped. Therefore, the operator is freed from the hassle of holding down the inching button for a long time and waiting, and cutting the excess welding wire B that has come out too much from the tip of the welding torch. Further, even in a conventional welding torch equipped with a feed motor, a current sensor 322 for overcurrent protection is provided. Since the arrival detection unit 323 determines based on the current detection value I ₂ detected by the current sensor 322, the welding system A1 does not need to be provided with a new detection mechanism for detecting the welding wire B. Therefore, it is possible to prevent the structure of each device from becoming complicated, and it is possible to suppress an increase in manufacturing cost.

Further, according to the present embodiment, when the feeding of the welding wire B is automatically stopped, the control unit 32 of the welding torch 3 displays on the display of the display unit 34 that the welding is automatically stopped. As a result, the worker can know that the automatic stop has occurred by looking at the display.

Further, according to the present embodiment, the welding torch 3 includes a feeding unit 31. Since the distance from the feeding section 31 to the tip of the welding torch 3 is short, the time required to manually feed the welding wire B fed to the feeding section 31 by automatic stop to the tip of the welding torch 3 is shortened. can do.

In the present embodiment, the case where the arrival detection unit 323 determines the arrival of the weld wire B by comparing the current detection value I ₂ with the current threshold value I _2th has been described, but the present invention is not limited to this. For example, a calculation unit for calculating the differential value of the current detection value I ₁ output by the current sensor 322 is provided, and the arrival detection unit 323 reaches the welding wire B by comparing the differential value calculated by the calculation unit with the threshold value. You may judge. In this case, the arrival of the weld wire B can be detected earlier than in the case where the current detection value I ₂ is compared with the current threshold value I _2th , but the possibility of erroneous detection of arrival is high. The arrival detection unit 323 may determine the arrival of the welding wire B based on the current detection value I ₂ , and the determination method may be appropriately set according to the waveform of the change in the current detection value I ₂ .

In the present embodiment, the case where the current threshold value I _2th is set as a fixed value has been described, but the present invention is not limited to this. The larger the speed command S _2H , the larger the current detection value I _2L when the feed motor 311 is in the no-load state. Therefore, when the current threshold value I _2th is set as a fixed value, the difference between the current threshold value I _2th and the current detection value I _2L becomes small when the speed command S _2H is large. Then, there is a high possibility that the arrival detection unit 323 will erroneously detect the arrival of the welding wire B. In order to prevent this, the arrival detection unit 323 may change the current threshold value I _2th according to the speed command S _2H . By increasing the current threshold value I _2th as the speed command S _2H becomes larger, it is possible to suppress the difference between the current threshold value I _2th and the current detection value I _2L from becoming smaller, and the arrival detection unit 323 increases the possibility of erroneous detection. Can be lowered. In the present embodiment, the speed command S _2H corresponds to the "command value of the feed rate of the welded wire" of the present invention. The arrival detection unit 323 may change the current threshold value I _2th according to the speed command S _1H , the actual rotation speed of the feed motor 311 or the feed motor 211, and the like.

In the present embodiment, the case where the arrival detection unit 323 determines the arrival of the weld wire B based on the current detection value I ₂ has been described, but the present invention is not limited to this. For example, when the control unit 32 includes a sensor that detects the electric power output from the drive unit 321 to the feed motor 311, the arrival detection unit 323 uses the welding wire based on the electric power detection value detected by the sensor. The arrival of B may be determined. When the control unit 32 includes a sensor that detects the voltage output from the drive unit 321 to the feed motor 311, the arrival detection unit 323 uses the welding wire based on the voltage detection value detected by the sensor. The arrival of B may be determined. Further, the arrival detection unit 323 may determine the arrival of the welding wire B based on the rotation speed of the feed motor 311. As described above, the rotational speed of the feed motor 311 is detected from the output of the encoder attached to the feed motor 311. When the feed motor 311 is driven by constant current control (constant torque control) in a no-load state, the load increases when the wire arrives, and the rotation speed of the feed motor 311 decreases. Therefore, the arrival of the wire can be detected based on the rotation speed of the feed motor 311. The set value of the current output to the feed motors 211 and 311 is set to an appropriate current value at which the tangential velocity of the feed roll 312 at no load is higher than the tangential velocity of the feed roll 212. Further, after the wire arrives, it is necessary to take measures to prevent buckling of the weld wire B. As a countermeasure for this, for example, a method of switching from constant current control to speed control, a method of lowering the speed command S ₁ , and the like can be considered, but the countermeasures are not limited.

In the present embodiment, the case where the current sensor 322 detects the current value of the drive signal output from the drive unit 321 to the feed motor 311 has been described, but the present invention is not limited to this. For example, the current sensor 322 may detect the current value of the current supplied to the drive unit 321 from a power source (not shown) included in the welding torch 3. Further, the current sensor 322 may detect the current value of the current supplied from the welding power supply device 1 or the wire feeding device 2 to the power supply of the welding torch 3. When the current value of the drive signal output to the feed motor 311 changes, these currents also change, so that the arrival of the welding wire B can be detected based on the current value detected by the current sensor 322. In these cases as well, it can be said that the current sensor 322 detects the current supplied to the feed motor 311.

In the present embodiment, the case where the control unit 22 includes the drive unit 221 and the control unit 32 includes the drive unit 321 and the current sensor 322 and the arrival detection unit 323 has been described, but the present invention is not limited to this. The control unit 11 may include a drive unit 221, a drive unit 321, a current sensor 322, and a reach detection unit 323. That is, the welding power supply device 1 may be configured to control the rotation speeds of the feed motor 211 and the feed motor 311 by adjusting the drive signals supplied to the feed motor 211 and the feed motor 311. In this case, the detection of the current value of the drive signal by the current sensor 322 and the determination by the arrival detection unit 323 can be performed inside the welding power supply device 1. In the case of the modification, the control unit 11 corresponds to the "control unit" of the present invention.

In the present embodiment, the case where the drive unit 221 controls the rotation speed of the feed motor 211 has been described, but the present invention is not limited to this. The drive unit 221 may control the torque of the feed motor 211.

In the present embodiment, the case where the feeding unit 21 feeds out the welding wire B by the rotation of the feeding roll 212 has been described, but the present invention is not limited to this. The feeding unit 21 may feed the welding wire B by another method.

In the present embodiment, the case where the feeding of the welding wire B is stopped (automatic stop) when the arrival of the welding wire B is detected has been described, but the present invention is not limited to this. The operator may be notified that the welding wire B has reached the welding torch 3 (feeding unit 31) without stopping the feeding of the welding wire B. The notification method may be a display on the display of the display unit 34, a voice from a speaker, lighting of a lamp, or vibration of the welding torch 3. The operator can recognize that the welding wire B has reached the welding torch 3 by these notifications, and can stop the feeding of the welding wire B.

[Modification example]
5 and 6 are diagrams for explaining a modification of the welding system A1 according to the first embodiment. FIG. 5 is a flowchart for explaining the inching process according to the modification. FIG. 6 is a timing chart according to the modified example. In the modification, the feeding of the welding wire B is not stopped when the welding wire B reaches the feeding portion 31, but the welding wire B is further fed to the tip of the welding torch 3 and then stopped. Is.

FIG. 5 shows an inching control process performed by the control unit 11 according to the modified example. Since the arrival detection process performed by the control unit 32 according to the modified example is the same as the flowchart shown in FIG. 4B, the description and description thereof will be omitted.

The flowchart of the inching control process shown in FIG. 5 is the same as the flowchart shown in FIG. 4A for steps S1 to S5. In the flowchart shown in FIG. 5, when the control unit 11 receives the arrival detection signal in step S4 (S4: YES), the processes of steps S6 and S7 are added before proceeding to step S5. , Different from the flowchart shown in FIG. 4 (a).

When the control unit 11 receives the arrival detection signal (S4: YES), the control unit 11 instructs the reduction of the feeding speed of the welding wire B (S6). Specifically, the control unit 11 transmits the speed command S 1 to the wire feeding device 2 while reducing the speed command S ₁ from S _1H to S _1L . Further, the speed command S ₂ is transmitted to the welding torch 3 while decreasing from S _2H to S _2L . Next, the control unit 11 waits for the predetermined time T3 to elapse (S7), and then instructs the welding wire B to stop feeding (S5). The predetermined time T3 is set based on the time when the welding wire B is fed at a speed corresponding to the speed command S _1L and the tip of the welding wire B reaches the tip of the welding torch 3. The predetermined time T3 is set from the time when the tip of the welding wire B reaches the feed roll 312 until the arrival is detected by the arrival detection unit 323, the feed amount during deceleration in step S6, and the feed amount during deceleration in step S6. , The amount of feed during deceleration in the stop of feed in step S5 is also taken into consideration. The predetermined time T3 corresponds to the "low-speed feeding time" of the present invention. Further, the predetermined time T3 is added to the predetermined time T2 (see step S16 in FIG. 4B) in the arrival detection process performed by the control unit 32. The process shown in the flowchart of FIG. 5 is an example, and the inching control process performed by the control unit 11 is not limited to the above-mentioned process.

FIG. 6 is a timing chart for explaining the automatic stop of feeding according to the modified example. Since the timing chart shown in FIG. 6 is the same as the timing chart shown in FIG. 3 from time t0 to time t2, the description thereof will be omitted.

When the current detection value I ₂ becomes the current threshold I _2th or more at time t2 (see FIG. 6C), the arrival detection unit 323 detects that the welding wire B has reached the feeding unit 31 and detects arrival. A signal is transmitted to the welding power supply device 1 (see FIG. 6D). Upon receiving the arrival detection signal, the welding power supply device 1 reduces the speed command S ₁ from S _1H to S _1L (see FIG. 6A), and reduces the speed command S ₂ from S _2H to S _2L . (See FIG. 6 (b)). As a result, the feeding motor 211 and the feeding motor 311 are decelerated, and the feeding speed of the welding wire B is lowered (see FIG. 6 (f)). The tension applied to the welding wire B increases to a predetermined value and then continues to the predetermined value (see FIG. 6 (e)). Accordingly, the current detection value I ₂ also increases to the current detection value I _2H , and then the current detection value I _2H is continued (see FIG. 6 (c)).

When the predetermined time T3 elapses from the time t2 and the time t3 is reached, the welding power supply device ₁ reduces the speed commands S1 and S2 to " ₀ " (see FIGS. 6A and 6B). .. As a result, the feeding motor 211 and the feeding motor 311 are stopped, and the feeding of the welding wire B is stopped (see FIG. 6 (f)). At this time, the tension applied to the welding wire B decreases to "0" (see FIG. 6 (e)), and the current detection value I ₂ decreases accordingly to "0" (FIG. 6 (c)). )reference).

Also in the case of this modification, when the feeding of the welding wire B is automatically stopped, the control unit 32 of the welding torch 3 displays on the display of the display unit 34 that the welding is automatically stopped. The worker can know that the automatic stop has occurred by looking at the display. Even when the welding wire B reaches the feeding unit 31 (time t2), the control unit 32 of the welding torch 3 may display to that effect on the display of the display unit 34. In this case, the worker can know in advance that the automatic stop will be performed soon by looking at the display.

Even after the welding wire B reaches the feeding unit 31 at time t2, the welding power supply device 1 may not change the speed command S ₁ (S ₂ ) from S _1H (S _2H ).

According to this modification, the welding wire B is fed to the tip of the welding torch 3, and then the feeding is automatically stopped. Therefore, the worker does not need to perform further inching after the automatic stop. Further, also in this modification, it is not necessary to provide a new detection mechanism for detecting the weld wire B.

[Second Embodiment]
FIG. 7 is a diagram for explaining the welding system A2 according to the second embodiment, and is a block diagram showing a functional configuration of the welding system A2. In the figure, the same or similar elements as the welding system A1 (see FIG. 2) are designated by the same reference numerals, and duplicate description will be omitted. In FIG. 7, the description of the welding torch 3 is omitted.

The welding system A2 according to the present embodiment is different from the welding system A1 in that it detects an abnormality in the configuration in which the welding wire B is fed.

The control unit 22 according to the present embodiment includes a speed detection unit 222 and a feed amount calculation unit 223.

The speed detection unit 222 detects the feeding speed of the welding wire B. The speed detection unit 222 includes, for example, an encoder attached to the feed motor 211. The encoder generates a pulse signal according to the rotation speed of the feed motor 211. The speed detection unit 222 detects the rotation speed of the feed motor 211 based on the pulse signal generated by the encoder. Then, the feeding speed of the welding wire B is calculated from the rotation speed. The speed detection unit 222 outputs the calculated feed rate to the feed amount calculation unit 223. Although the description is omitted, the wire feeding device 2 according to the first embodiment also includes a speed detection unit 222.

The feed amount calculation unit 223 inputs the feed rate from the speed detection unit 222, and calculates the feed amount of the welding wire B from the start of inching. The feed amount calculation unit 223 calculates the feed amount of the welding wire B from the start of inching by integrating the feed rate input from the speed detection unit 222. The method of calculating the amount of feed is not limited. The control unit 22 transmits the feed amount calculated by the feed amount calculation unit 223 from the start of inching to the welding power supply device 1. The speed detection unit 222 may output the rotation speed of the feed motor 211 to the feed amount calculation unit 223, and the feed amount calculation unit 223 may calculate the feed speed of the welding wire B from the rotation speed.

The control unit 11 according to the present embodiment further includes an abnormality detection unit 111.

The abnormality detection unit 111 transmits the welding wire B based on the feed amount from the start of inching received from the control unit 22 of the wire feeding device 2 and the arrival detection signal received from the control unit 32 of the welding torch 3. Detects anomalies in the feeding configuration. If there is no abnormality, when the amount of feed from the start of inching reaches the length L1 of the feed route from the feed unit 21 (feed roll 212) to the feed unit 31 (feed roll 312). The arrival detection signal should be received. Therefore, if the arrival detection signal is not received even if the feed amount from the start of inching exceeds L1, or if the arrival detection signal is received before the feed amount from the start of inching reaches L1, there is an abnormality. Can be judged.

The abnormality detection unit 111 determines that there is an abnormality when the arrival detection signal is not received even if the feed amount from the start of inching becomes the first predetermined value (L1 + α) or more. In this case, it is conceivable that the welding wire B is buckled in the liner, an abnormality in the feeding unit 21 or the driving unit 221, an abnormality in the current sensor 322, or the like. α (> 0) is an adjustment value for preventing erroneous detection of abnormality. Further, the abnormality detection unit 111 determines that there is an abnormality when the arrival detection signal is received when the feed amount from the start of inching is equal to or less than the second predetermined value (L1-β). In this case, an abnormality of the feeding unit 31 or the driving unit 321, an abnormality of the current sensor 322, or the like can be considered. β (> 0) is an adjustment value for preventing erroneous detection of abnormality.

When the abnormality detecting unit 111 detects an abnormality, the control unit 11 stops the feeding of the welding wire B and notifies that the abnormality has occurred. Specifically, the control unit 11 stops the feeding of the welding wire B by switching the speed command S ₁ (S ₂ ) from S _1H (S _2H ) to “0”. Further, the control unit 11 transmits an abnormality signal indicating that an abnormality has occurred to the control unit 32 of the welding torch 3. The anomaly signal contains information indicating the type of anomaly. Upon receiving the abnormality signal, the control unit 32 displays on the display of the display unit 34 the fact that the abnormality has occurred and the description according to the type of the abnormality. The method of notifying the abnormality is not limited. Further, the welding power supply device 1 or the wire feeding device 2 may notify the abnormality.

According to this embodiment, it is possible to detect an abnormality in the configuration in which the welding wire B is fed. Then, when an abnormality is detected, the feeding of the welding wire B is stopped, so that a failure or an accident can be prevented. Further, when an abnormality is detected, the operator can be notified of the occurrence of the abnormality. Further, also in this embodiment, it is not necessary to provide a new detection mechanism for detecting the weld wire B.

[Third Embodiment]
8 and 9 are diagrams for explaining the welding system A3 according to the third embodiment. FIG. 8 is a block diagram showing a functional configuration of the welding system A3. FIG. 9 is a timing chart for explaining the automatic stop of feeding of the welding wire B. In these figures, elements that are the same as or similar to the welding system A1 (see FIGS. 2 and 3) are designated by the same reference numerals, and duplicate description is omitted.

The welding system A3 according to the present embodiment is different from the welding system A1 in that the wire feeding device 2 detects that the welding wire B has reached the feeding unit 31.

The control unit 32 according to the present embodiment does not include the arrival detection unit 323. The current sensor 322 is omitted because it is not related to the detection of the arrival of the welding wire B in the present embodiment. On the other hand, the control unit 22 according to the present embodiment includes a current sensor 224 and a reach detection unit 225.

The current sensor 224 is a sensor that detects the current value of the drive signal output from the drive unit 221 to the feed motor 211. The control unit 22 has an overcurrent protection function for protecting the feed motor 211 and the like from overcurrent based on the current detection value I ₁ detected by the current sensor 224. Further, the current detection value I ₁ detected by the current sensor 224 is also output to the arrival detection unit 225.

The arrival detection unit 225 detects that the welding wire B has reached the feeding unit 31 based on the current detection value I ₁ input from the current sensor 224. The welding wire B is first fed by the feeding section 21 of the wire feeding device 2, and after the welding wire B reaches the feeding section 31 of the welding torch 3, it is fed by the feeding section 21 and the feeding section 31. Will be sent. The feeding motor 211 of the feeding section 21 is heavily loaded until the welding wire B reaches the feeding section 31, but the welding wire B is applied to the feeding section 31 (strictly speaking, the feeding roll 312). After reaching it, the load is reduced. Therefore, before and after the welding wire B reaches the feeding unit 31, the current value of the drive signal output from the driving unit 221 to the feeding motor 211 changes. The arrival detection unit 225 has reached the welding wire B from the change in the current value of the drive signal output to the feeding motor 211 based on the current detection value I ₁ input from the current sensor 224. Detect that.

FIG. 9C shows the time change of the current detection value I ₁ detected by the current sensor 224. From time t4 to time t1, the feeding amount of the welding wire B increases as time elapses. Since the feeding resistance of the welding wire B gradually increases accordingly, the load applied to the feeding motor 211 also gradually increases. Accordingly, the current detection value I ₁ also increases little by little. Then, when the welding wire B reaches the feeding unit 31 at time t1, the load applied to the feeding motor 211 is reduced. As a result, the current detection value I ₁ is reduced. FIG. 9D shows the time change of the current differential value obtained by differentiating the current detection value I ₁ . As shown in FIG. 9D, the current differential value is a positive value from time t4 to time t1. Then, as the current detection value I ₁ decreases at time t1, the current differential value becomes a negative value. The arrival detection unit 225 detects that the welding wire B has reached the feeding unit 31 based on this change.

Specifically, the arrival detection unit 225 differentiates the current detection value I ₁ input from the current sensor 224 to calculate the current differential value. Then, the arrival detection unit 225 compares the calculated current differential value with the differential threshold value, and when the current differential value becomes equal to or less than the differential threshold value, determines that the welding wire B has reached the feeding unit 31. In this embodiment, the differential threshold value is set to "0". The differential threshold is not limited. Further, the arrival detection unit 225 may detect that the welding wire B has reached the feeding unit 31 by another method.

According to the present embodiment, in the arrival detection unit 225, the welding wire B reaches the feeding unit 31 when the current differential value obtained by differentiating the current detection value I ₁ input from the current sensor 224 becomes equal to or less than the differential threshold value. It is determined that this has been done, and the arrival detection signal is transmitted to the welding power supply device 1. Upon receiving the arrival detection signal, the control unit 11 of the welding power supply device 1 stops the feeding of the welding wire B. Therefore, the operator is freed from the hassle of holding down the inching button for a long time and waiting, and cutting the excess welding wire B that has come out too much from the tip of the welding torch. Further, the conventional wire feeding device is also provided with a current sensor 224 for overcurrent protection. Since the arrival detection unit 225 determines based on the current detection value I ₁ detected by the current sensor 224, the welding system A3 does not need to be provided with a new detection mechanism for detecting the welding wire B. Therefore, it is possible to prevent the structure of each device from becoming complicated, and it is possible to suppress an increase in manufacturing cost.

In the third embodiment, the control unit 32 of the welding torch 3 may include the arrival detection unit 323. In the case of this configuration, the arrival detection unit 225 and the arrival detection unit 323 can detect the arrival of the welding wire B, respectively. The delivery may be stopped when both the arrival detection unit 225 and the arrival detection unit 323 detect the arrival, or the delivery may be stopped when either the arrival detection unit 225 or the arrival detection unit 323 detects the arrival. May be stopped.

[Fourth Embodiment]
10 and 11 are diagrams for explaining the welding system A4 according to the fourth embodiment. FIG. 10 is a schematic diagram showing the overall configuration of the welding system A4. FIG. 11 is a block diagram showing a functional configuration of the welding system A4. In these figures, elements that are the same as or similar to the welding system A1 (see FIGS. 1 and 2) are designated by the same reference numerals, and duplicate description is omitted. In FIG. 11, the description of the internal configuration of the welding torch 3'is omitted.

The welding system A4 according to the present embodiment is different from the welding system A1 in that the welding torch 3'does not function as a feed device on the pull side and instead includes a pull feeder 9 which is a feed device on the pull side. ..

The welding torch 3'is the welding torch 3 (see FIG. 2) according to the first embodiment, which does not include the feeding unit 31, the driving unit 321 and the current sensor 322, and the arrival detection unit 323. That is, the welding torch 3'does not have a function of feeding the welding wire B, and other functions are the same as those of the welding torch 3.

The pull feeder 9 feeds the welding wire B, and pulls the welding wire B to apply tension to reduce the feeding resistance of the welding wire B. As shown in FIG. 10, the pull feeder 9 is arranged closer to the welding torch 3'on the feeding path of the welding wire B between the wire feeding device 2 and the welding torch 3'. Specifically, the pull feeder 9 is connected to the wire feeding device 2 by a torch cable 39. Further, the pull feeder 9 is connected to the welding torch 3'by a torch cable 39'which has the same configuration as the torch cable 39. The length of the torch cable 39 is, for example, about a dozen meters, whereas the length of the torch cable 39'is, for example, about several meters. The pull feeder 9 and the wire feeding device 2 communicate with each other via a communication line (not shown) provided inside the torch cable 39. Further, the pull feeder 9 and the welding torch 3'communicate via a communication line (not shown) provided inside the torch cable 39'. The pull feeder 9 and the welding power supply device 1 communicate with each other by mediating the wire feeding device 2. The pull feeder 9 and the welding power supply device 1 may directly communicate with each other. Moreover, the communication method is not limited. As shown in FIG. 11, the pull feeder 9 includes a feeding unit 91 and a control unit 92.

The feeding unit 91 is driven by a drive signal input from the control unit 92 to pull the welding wire B. The feeding unit 91 includes a feeding motor 911, a feeding roll 912, and a pressurizing roll 913.

The feeding motor 911 generates a driving force for feeding the welding wire B. The feed motor 911 is driven by a drive signal input from the control unit 92 (drive unit 921 described later). The feed motor 911 is, for example, a brushless motor, and the rotation speed is controlled by adjusting the drive signal. The control unit 92 (drive unit 921 described later) controls the rotation speed of the feed motor 911 by adjusting the pulse width of the drive signal, for example, by pulse width modulation or the like.

The feed roll 912 is attached to the rotating shaft of the feed motor 911, and the torque generated by the feed motor 911 is transmitted to rotate the feed roll 912. The method of transmitting the torque of the feed motor 911 to the feed roll 912 is not limited. The welding wire B is in contact with the feed roll 912, and the torque of the feed roll 912 is converted into a tangential force for pulling the weld wire B. Therefore, the welding wire B is towed by driving the feed motor 911.

The pressure roll 913 is arranged so as to face the feed roll 912 with the welding wire B interposed therebetween, and pressurizes the weld wire B to the feed roll 912 side. As a result, the welding wire B is fed according to the rotation of the feed roll 912.

The control unit 92 is realized by, for example, a microcomputer or the like, and controls the pull feeder 9. The control unit 92 feeds the welding wire B by driving the feeding unit 91 based on a command from the control unit 11 of the welding power supply device 1. The control unit 92 includes a drive unit 921, a current sensor 922, and a arrival detection unit 923.

The drive unit 921 controls the drive of the feed unit 91 to control the feed of the welding wire B. The drive unit 921 outputs a drive signal to the feed motor 911 of the feed unit 91 based _on the speed command S2 received from the control unit 11 of the welding power supply device 1. An encoder (not shown) is attached to the feed motor 911, and the control unit 92 detects the rotation speed of the feed motor 911 from the pulse signal input from the encoder. The encoder may be an optical encoder or a magnetic encoder. The drive unit 921 adjusts the drive signal so that the detected rotation speed of the feed motor 911 _matches the rotation speed according to the speed command S2, and performs feedback control. The method for detecting the rotation speed is not limited.

The current sensor 922 is a sensor that detects the current value of the drive signal output from the drive unit 921 to the feed motor 911. The control unit 92 has an overcurrent protection function for protecting the feed motor 911 and the like from overcurrent based on the current detection value I ₂ detected by the current sensor 922. Further, the current detection value I ₂ detected by the current sensor 922 is also output to the arrival detection unit 923.

The arrival detection unit 923 detects that the welding wire B has reached the feeding unit 91 based on the current detection value I ₂ input from the current sensor 922. The welded wire B is first fed by the feeding section 21 of the wire feeding device 2, and after the welding wire B reaches the feeding section 91 of the pull feeder 9, it is fed by the feeding section 21 and the feeding section 91. Will be paid. The feeding motor 911 of the feeding section 91 is in a no-load state until the welding wire B reaches the feeding section 91, but the welding wire B reaches the feeding section 91 (strictly speaking, the feeding roll 912). After that, the load is applied. Therefore, before and after the welding wire B reaches the feeding unit 91, the current value of the drive signal output from the driving unit 921 to the feeding motor 911 changes. The arrival detection unit 923 has reached the welding wire B from the change in the current value of the drive signal output to the feeding motor 911 based on the current detection value I ₂ input from the current sensor 922. Detect that. The specific detection method is the same as that of the arrival detection unit 323 according to the first embodiment. When the arrival detection unit 923 detects that the welding wire B has reached the feeding unit 91, the arrival detection unit 923 generates a arrival detection signal. The arrival detection signal is transmitted to the welding power supply device 1.

In the present embodiment, the feeding unit 21 corresponds to the "first feeding unit" of the present invention, and the feeding unit 91 corresponds to the "second feeding unit" of the present invention. Further, the control unit 11, the control unit 22, and the control unit 92 correspond to the "control unit" of the present invention.

According to the present embodiment, the arrival detection unit 923 determines that the welding wire B has reached the feeding unit 91 when the current detection value I ₂ input from the current sensor 922 becomes the current threshold I _2th or more. Then, the arrival detection signal is transmitted to the welding power supply device 1. Upon receiving the arrival detection signal, the control unit 11 of the welding power supply device 1 stops the feeding of the welding wire B. Therefore, the operator is freed from the hassle of holding down the inching button for a long time and waiting, and cutting the excess welding wire B that has come out too much from the tip of the welding torch. Further, the conventional pull feeder is also provided with a current sensor 922 for overcurrent protection. Since the arrival detection unit 923 makes a determination based on the current detection value I ₂ detected by the current sensor 922, the welding system A4 does not need to be provided with a new detection mechanism for detecting the welding wire B. Therefore, it is possible to prevent the structure of each device from becoming complicated, and it is possible to suppress an increase in manufacturing cost.

Further, according to the present embodiment, the welding torch 3'does not need to be provided with a configuration for feeding the welding wire B, so that the size and weight can be reduced.

In the fourth embodiment, the welding torch 3'may include a feeding unit 31, a driving unit 321, a current sensor 322, and a arrival detection unit 323 (that is, the welding torch 3). In the case of this configuration, before the welding wire B reaches the feeding unit 31 of the welding torch 3 and automatically stops, when the welding wire B reaches the feeding unit 91 of the pull feeder 9, it automatically stops soon. It can be notified in advance. Further, the welding wire B may be automatically stopped twice when it reaches the feeding unit 91 of the pull feeder 9 and when it reaches the feeding unit 31 of the welding torch 3.

In the above 1st to 4th embodiments, the case where the welding wire B is fed in the welding systems A1 to A4 has been described, but the present invention is not limited to this. The present invention is also applicable to a wire feeding system that feeds wires other than the welding wire B. For example, the present invention can be applied to a wire feeding system that feeds a sprayed wire in a thermal spraying system and a wire feeding system that feeds a brazing wire in a brazing system.

The wire feeding system and the welding system according to the present invention are not limited to the above-described embodiments. The specific configuration of each part of the wire feeding system and the welding system according to the present invention can be freely redesigned.

A1, A2, A3, A4: Welding system 1: Welding power supply device 11: Control unit 111: Abnormality detection unit 2: Wire feeding device 21: Feeding unit 211: Feeding motor 212: Feeding roll 213: Pressurized roll 22: Control unit 221: Drive unit 222: Speed detection unit 223: Feed amount calculation unit 224: Current sensor 225: Reach detection unit 23: Wire reel 3, 3': Welding torch 31: Feed unit 311: Feed motor 312: Feeding roll 313: Pressurizing roll 32: Control unit 321: Drive unit 322: Current sensor 323: Reach detection unit 33: Operation unit 34: Display unit 9: Pull feeder 91: Feeding unit 911: Feeding motor 912: Feed roll 913: Pressurized roll 92: Control unit 921: Drive unit 922: Current sensor 923: Reach detection unit 39, 39': Torch cable 41, 42: Power cable 5: Power transmission line 6: Gas cylinder 7: Gas piping 8: Communication line B: Welding wire P: Power system W: Work piece

Claims (10)

The first feeding unit that feeds the wire and
A second feeding unit, which is arranged on the feeding direction side of the wire from the first feeding section, has a feeding motor, and feeds the wire by rotation of the feeding motor.
A control unit that controls the first feeding unit and the second feeding unit,
Equipped with
The control unit
An electrical signal supplied to the feed motor or a sensor that detects the rotational speed of the feed motor.
Based on the detection value detected by the sensor, the arrival detection unit that detects that the wire has reached the second feeding unit, and the arrival detection unit.
Equipped with
When the arrival detection unit detects the arrival of the wire, the first feeding unit and the second feeding unit are stopped.
A wire feeding system characterized by that. The first feeding unit that feeds the wire and
A second feeding unit, which is arranged on the feeding direction side of the wire from the first feeding section, has a feeding motor, and feeds the wire by rotation of the feeding motor.
A control unit that controls the first feeding unit and the second feeding unit,
Equipped with
The control unit
An electrical signal supplied to the feed motor or a sensor that detects the rotational speed of the feed motor.
Based on the detection value detected by the sensor, the arrival detection unit that detects that the wire has reached the second feeding unit, and the arrival detection unit.
Equipped with
When the arrival detection unit detects the arrival of the wire, the feeding speed of the wire by the first feeding unit and the second feeding unit is lowered, and after the feeding speed is lowered, a predetermined low speed is obtained. When the feeding time has elapsed, the first feeding section and the second feeding section are stopped.
A wire feeding system characterized by that. The first feeding unit, which has a feeding motor and feeds wires by the rotation of the feeding motor,
A second feeding section arranged on the feeding direction side of the wire from the first feeding section and feeding the wire, and a second feeding section.
A control unit that controls the first feeding unit and the second feeding unit,
Equipped with
The control unit
A sensor that detects an electrical signal supplied to the feed motor,
Based on the detection value detected by the sensor, the arrival detection unit that detects that the wire has reached the second feeding unit, and the arrival detection unit.
Equipped with
When the arrival detection unit detects the arrival of the wire, the first feeding unit and the second feeding unit are stopped.
A wire feeding system characterized by that. The first feeding unit, which has a feeding motor and feeds wires by the rotation of the feeding motor,
A second feeding section arranged on the feeding direction side of the wire from the first feeding section and feeding the wire, and a second feeding section.
A control unit that controls the first feeding unit and the second feeding unit,
Equipped with
The control unit
A sensor that detects an electrical signal supplied to the feed motor,
Based on the detection value detected by the sensor, the arrival detection unit that detects that the wire has reached the second feeding unit, and the arrival detection unit.
Equipped with
When the arrival detection unit detects the arrival of the wire, the feeding speed of the wire by the first feeding unit and the second feeding unit is lowered, and after the feeding speed is lowered, a predetermined low speed is obtained. When the feeding time has elapsed, the first feeding section and the second feeding section are stopped.
A wire feeding system characterized by that. The arrival detection unit is
A comparison unit for comparing the detected value with the threshold value is provided.
The arrival of the wire is detected based on the comparison result in the comparison unit.
The wire feeding system according to any one of claims 1 to 4 . The arrival detection unit is
A calculation unit that calculates the differential value of the detected value, and
A comparison unit that compares the differential value with the threshold value,
Equipped with
The arrival of the wire is detected based on the comparison result in the comparison unit.
The wire feeding system according to any one of claims 1 to 4 . The wire feeding system according to claim 5 or 6 , wherein the arrival detection unit changes the threshold value according to a command value of the feeding speed of the wire. The electrical signal is an electric current,
The wire feeding system according to any one of claims 1 to 7 . Welding torch and
A welding power supply that supplies electric power to the welding torch,
The wire feeding system according to any one of claims 1 to 8, wherein the wire is fed to the welding torch.
A welding system characterized by being equipped with. The second feeding unit is arranged on the welding torch.
The welding system according to claim 9.

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