JP2019155444A - Wire feeding system, and welding system - Google Patents

Abstract

To provide a wire feeding system which detects arrival of a wire without addition of a new detection mechanism, and a welding system comprising the wire feeding system.SOLUTION: A wire feeding system of a welding system A1 comprises: a feeding part 21 which feeds a welding wire B; a feeding part 31 which is located on a feeding direction side of the welding wire B with respect to the feeding part 21, has a feeding motor 311, and feeds the welding wire B by rotation of the feeding motor 311; and control parts 11, 22, 32 which control the feeding part 21 and the feeding part 31. The control part 32 comprises: a current sensor 322 which detects electric current fed to the feeding motor 311; and an arrival detection part 323 which detects that the welding wire B arrives at the feeding part 31 based on a current detection value Idetected by the current sensor 322.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a wire feeding system that feeds a wire, and a welding system including the wire feeding system.

  In a consumable electrode type welding system that performs welding using the supplied welding wire as an electrode, the welding work range is widened by connecting the wire feeding device and the welding torch with a long torch cable. . However, when the length of the torch cable is increased, the feeding resistance of the welding wire increases, so that the welding wire cannot be smoothly fed. In this case, there arises a problem that the arc becomes unstable. As a method for solving this problem, a structure for feeding the welding wire is added near the tip of the welding wire feeding path, and the welding wire is fed by pulling the welding wire and applying tension by the construction. Reducing the resistance is done. Such a welding wire feeding system is called a push-pull feeding system.

  Further, in the consumable electrode type welding system, the operator performs an inching operation for sending 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 being fed in the middle of the course, the operator sees the tip of the welding wire protruding from the tip of the welding torch and releases the inching button. In the case of the push-pull feeding system, since the welding wire feeding path is long, the operator needs to keep pressing the inching button and wait for a long time (for example, several tens of seconds to several minutes). In addition, if the timing for releasing the inching button is delayed, the welding wire comes out of the tip of the welding torch, so the operator has to cut off the excess welding wire with pliers or the like.

  In order to eliminate the burden on these workers, a method has been proposed in which the arrival of the welding wire is detected and automatically stopped. For example, Patent Document 1 discloses a method for electrically detecting that a welding wire has contacted a contact tip at the tip of a welding torch. Patent Document 2 discloses a method for detecting the arrival of a welding wire using a non-contact sensor.

Japanese Utility Model Publication No. 5-13669 JP 2017-24043 A

  However, in these methods, it is necessary to add a new detection mechanism in order to detect the arrival of the welding wire. The addition of a new detection mechanism complicates the structure of the welding torch or the welding power source and increases the manufacturing cost. It is also possible to consider a method in which the feeding amount of the welding wire is calculated from the number of rotations of the feeding motor, and the feeding is stopped when the predetermined feeding amount is reached. However, if a predetermined feed amount that differs depending on the length of the torch cable is set incorrectly, or if the calculation of the feed amount is started when the welding wire has advanced halfway through the feed path, the welding wire A large amount will jump out of the tip. Therefore, in 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 the wire in the inching operation is also a problem in systems other than the welding system. For example, the same problem occurs when a spray wire is fed to a spray gun in a spraying system or when a brazing wire is fed in a brazing system.

  The present invention has been conceived under the circumstances described above, and includes a wire feeding system that can detect 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 present invention takes the following technical means.

  The wire feeding system provided by the first aspect of the present invention includes a first feeding unit that feeds a wire, and a feeding motor that is disposed on the wire feeding direction side from the first feeding unit. 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, Based on an electrical signal supplied to the feed motor, or a sensor that detects the rotation speed of the feed motor, and a detection value detected by the sensor, the wire has reached the second feed unit. And an arrival detection unit for detecting this. According to this configuration, the wire is first fed by the first feeding unit, and is fed by the first feeding unit and the second feeding unit after the wire reaches the second feeding unit. The feeding motor of the second feeding unit is in an unloaded state until the wire reaches the second feeding unit, but is loaded after the wire reaches the second feeding unit. Therefore, the electrical signal output to the feeding motor changes before and after the wire reaches the second feeding unit. The arrival detection unit detects that the wire has reached the second feeding unit from the change in the electrical signal output to the feeding motor based on the detection value detected by the sensor. The wire feeding system includes 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, it is not necessary to add a new detection mechanism.

  The “electrical signal” includes current, power, voltage, and the like. The “sensor for detecting an electrical signal supplied to the feed motor” is not limited to a sensor for detecting an electrical signal by a connection line connecting the drive circuit and the feed motor. A sensor for detecting an electrical signal supplied to the feed motor by detecting an electrical signal with a connection line connecting the two is also included.

  The wire feeding system provided by the second aspect of the present invention includes a first feeding unit that has a feeding motor and feeds the wire by rotation of the feeding motor, and the first feeding unit includes the first feeding unit and the first feeding unit. A second feeding unit that is disposed on the wire feeding direction side and feeds the wire; and a control unit that controls the first feeding unit and the second feeding unit, the control unit comprising: A sensor that detects an electrical signal supplied to the feeding motor, and an arrival detection unit that detects that the wire has reached the second feeding unit based on a detection value detected by the sensor. It is characterized by that. According to this configuration, the wire is first fed by the first feeding unit, and is fed by the first feeding unit and the second feeding unit after the wire reaches the second feeding unit. The feeding motor of the first feeding unit is subjected to a large load until the wire reaches the second feeding unit, but the load is reduced after the wire reaches the second feeding unit. Therefore, the electrical signal output to the feeding motor changes before and after the wire reaches the second feeding unit. The arrival detection unit detects that the wire has reached the second feeding unit from the change in the electrical signal output to the feeding motor based on the detection value detected by the sensor. The wire feeding system includes 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, it is not necessary 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 detection value with a threshold value, and detects the arrival of the wire based on a 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 that calculates a differential value of the detection value and a comparison unit that compares the differential value with a threshold value, and the comparison result in the comparison unit Based on the above, the arrival of the wire is detected. According to this configuration, the arrival of the wire can be detected based on the change in the increase rate of the detection value.

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

  In a preferred embodiment of the present invention, the electrical signal is a current. According to this configuration, the arrival of the 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 detection unit detects the arrival of the wire. According to this configuration, the feeding of the wire can be automatically stopped when it reaches the second feeding unit.

  In a preferred embodiment of the present invention, when the arrival detection unit detects the arrival of the wire, the control unit feeds the wire by the first feeding unit and the second feeding unit. When the predetermined low speed feeding time has elapsed after the feeding speed is lowered, the first feeding unit and the second feeding unit are stopped. According to this configuration, the feeding of the wire can be automatically stopped when the low-speed feeding time has elapsed after reaching the second feeding unit. If the low-speed feeding time is appropriately set, the wire can be fed to the tip of the welding torch and then stopped.

  In preferable embodiment of this invention, when the said arrival detection part detects the arrival of the said wire, the alerting | reporting part which alert | reports the arrival of the said 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 a feeding speed of the wire by the first feeding unit, and a feeding speed detected by the speed detection unit. A feed amount calculation unit that calculates a feed amount from the start of feeding the wire, and the arrival detection unit even if the feed amount calculated by the feed amount calculation unit is equal to or greater than a first predetermined value. Includes an abnormality detection unit that detects an abnormality when the arrival of the wire is not detected. According to this configuration, an abnormality such as a buckling of the wire or the first feeding unit can be detected.

  In a preferred embodiment of the present invention, the control unit integrates a speed detection unit that detects a feeding speed of the wire by the first feeding unit, and a speed detected by the speed detection unit, A feeding amount calculation unit that calculates a feeding amount from the start of feeding of the wire; and when the feeding amount calculated by the feeding amount calculation unit is equal to or less than a second predetermined value, the arrival detection unit And an abnormality detection unit that detects an abnormality when the arrival of is detected. According to this configuration, an abnormality such as the second feeding unit can be detected.

  The welding system provided by the second aspect of the present invention includes a welding torch, a welding power supply device that supplies power to the welding torch, and a wire that feeds the welding torch according to the first aspect of the present invention. And a wire feeding system provided.

  In a preferred embodiment of the present invention, the second feeding unit is disposed 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 unit, and is fed by the first feeding unit and the second feeding unit after the wire reaches the second feeding unit. The feeding motor of the second feeding unit is in an unloaded state until the wire reaches the second feeding unit, but is loaded after the wire reaches the second feeding unit. Therefore, the electrical signal output to the feeding motor changes before and after the wire reaches the second feeding unit. The arrival detection unit detects that the wire has reached the second feeding unit from the change in the electrical signal output to the feeding motor based on the detection value detected by the sensor. The wire feeding system includes 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, it is not necessary to add a new detection mechanism.

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

It is a schematic diagram showing the whole welding system composition concerning a 1st embodiment. It is a block diagram which shows the function 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 which the control part of a welding power supply device performs, (b) is the arrival which the control part of a welding torch performs. The detection process is shown. It is a flowchart for demonstrating the inching process in a modification. It is a timing chart for explaining automatic stop of feeding of a welding wire in a modification. It is a block diagram which shows the function structure of the welding system which concerns on 2nd Embodiment. It is a block diagram which shows the function structure of the welding system which concerns on 3rd Embodiment. It is a timing chart for explaining automatic stop of feeding of a welding wire in a 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 function structure of the welding system shown in FIG.

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

[First Embodiment]
1-2 is a figure for demonstrating welding system A1 which concerns on 1st 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, a welding system A1 includes a welding power source device 1, a wire feeding device 2, a welding torch 3, power cables 41 and 42, a power transmission line 5, a gas cylinder 6, a gas pipe 7, a communication line 8, and A torch cable 39 is provided. 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. In the torch cable 39, a power cable 41, a gas pipe 7, a liner, a power transmission line and a communication line are arranged inside the cable. The length of the torch cable 39 is, for example, about tens of meters. The liner disposed on the torch cable 39 is a part of the feeding path of the welding wire B. Since the torch cable 39 is long, the feeding path is also long. The power cable 41, the gas pipe 7, the liner, the power transmission line and the communication line inside the torch cable 39 are the power cable 41, the gas pipe 7, the liner, the power transmission line 5 and the communication inside the wire feeding device 2, respectively. Connected to line 8.

  One output terminal of the welding power source device 1 is connected to the welding torch 3 via the power cable 41. The wire feeding device 2 feeds the welding wire B to the welding torch 3 and causes the tip of the welding wire B to protrude 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 source apparatus 1 is connected to the workpiece W via the power cable 42. The welding power source 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.

  In the present embodiment, as shown in FIG. 2, the welding torch 3 includes a feeding unit 31 that is configured to feed the welding wire B. That is, in the feeding path of the welding wire B, two feeding units 21 (wire feeding device 2) and feeding unit 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 travels) (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 welding 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) constitute a push-pull type wire feeding system. It can be considered that the welding torch 3 includes the feeding unit 31, or the feeding unit 31, which is a part of the configuration of the wire feeding system, can be considered to be disposed on the welding torch 3. it can.

  Electric power (for example, DC 24 V) for driving the feeding motor 211 and the like is supplied from the welding power supply device 1 to the wire feeding device 2 through the power transmission line 5. 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 source device 1. Further, the wire feeding device 2 and the welding torch 3 may be supplied with power from other than the welding power source device 1.

  The welding power source device 1 and the wire feeding device 2 communicate via the communication line 8. Further, the wire feeder 2 and the welding torch 3 communicate with each other via a communication line (not shown) provided in the torch cable 39. The welding torch 3 and the welding power source device 1 communicate with each other through the wire feeding device 2. Note that the welding torch 3 and the welding power source device 1 may directly communicate with each other. Also, the communication method is not limited, and power line carrier communication using power transmission lines and power cables 41 and 42 may be used, or wireless communication may be used. In addition, transmission of information among the welding power source device 1, the wire feeding device 2, and the welding torch 3 may be performed by a voltage or current level or pulse via a control line.

  The welding system A1 uses a shielding 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 feeder 2. The welding system A1 may circulate cooling water through 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 the power. Further, the welding power source device 1 converts the three-phase AC power input from the power system P into DC power for driving the feeding motor 311 of the wire feeding device 2, and the like via the power transmission line 5. Output to the wire feeder 2.

As shown in FIG. 2, the welding power source device 1 includes a control unit 11. The control part 11 is implement | achieved by the microcomputer etc., for example, and controls the welding power supply device 1. FIG. The control part 11 controls the inverter circuit which is not illustrated so that electric power may be output 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 performing welding at the time of welding and inching. The feeding of the wire B is controlled. Specifically, the control unit 11 transmits a speed command S ₁ for instructing the feeding speed of the welding 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. Control unit 22, based on the speed command S ₁ received, it controls the delivery unit 21. The control unit 32 based on the speed command S ₂ received, it controls the delivery unit 31. The control unit 11 transmits the speed commands S ₁ and S ₂ so that the feeding speed by the feeding part 31 is several percent greater than the feeding speed by the feeding part 21. Since the feeding speed by the feeding section 31 (pull side feeding section) is larger than the feeding speed by the feeding section 21 (push side feeding section), the welding wire B is tensioned. Thereby, the feeding resistance of the welding wire B is suppressed, and buckling of the welding wire B is prevented. Details of control for inching of 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 drive signal input from the control unit 22 and is configured to feed the welding wire B. The feeding unit 21 includes a feeding motor 211, a feeding roll 212, and a pressure 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 (a drive unit 221 described later). The feed motor 211 is a brushless motor, for example, and the rotation speed is controlled by adjusting the drive signal. The control unit 22 (a drive unit 221 to be described later) controls the rotation speed of the feed motor 211 by adjusting the pulse width of the drive signal by, for example, pulse width modulation.

  The feed roll 212 is attached to the rotation shaft of the feed motor 211, and rotates by receiving torque generated by the feed motor 211. The feed roll 212 is not limited to one that is directly attached to the rotation shaft of the feed motor 211. The configuration may be such that the torque of the feed motor 211 is transmitted to the feed roll 212 and the feed roll 212 is rotated by one or more gears. 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 welding wire B. Therefore, the welding wire B is sent out by driving the feed motor 211.

  The pressure roll 213 is disposed so as to face the feed roll 212 with the welding wire B interposed therebetween, and pressurizes the welding wire B toward the feed roll 212 side. Thereby, the welding wire B is fed according to the rotation of the feeding roll 212.

  The control unit 22 is realized by a microcomputer, for example, 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 source apparatus 1 and opens a gas electromagnetic valve (not shown). The shield gas is supplied 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 feeding of the welding wire B by controlling the driving of the feeding unit 21. The drive unit 221 outputs a drive signal to the feed motor 211 of the feed unit 21 based on the speed command S ₁ 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 performs feedback control by adjusting the drive signal so that the detected rotation speed of the feed motor 211 matches the rotation speed corresponding to the speed command S ₁ . The method for detecting the rotational speed is not limited.

  In addition, although the wire feeder 2 is provided with cylindrical guide members, such as an inlet liner, an inlet guide, and an outlet guide, illustration is abbreviate | omitted. The inlet liner and the inlet guide guide the welding wire B from the wire reel 23 around which the welding wire B is wound to the feed roll 212. The outlet guide guides the welding wire B fed by the feeding roll 212 to the feeding port of the wire feeding device 2. The welding wire B delivered from the wire feeder 2 is guided to the tip of the welding torch 3 through the torch cable 39 and the inside of the liner provided inside 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 constitute a feeding path of the welding wire B.

  The welding torch 3 welds the workpiece W with welding power supplied from the welding power source device 1. Further, the welding torch 3 has a configuration for feeding the welding wire B, and pulls the welding wire B to apply tension, thereby reducing the feeding resistance of the welding wire B. As shown in FIG. 2, the welding torch 3 includes a feeding unit 31, a control unit 32, an operation unit 33, and a display unit 34.

  The feeding unit 31 is driven by a drive signal input from the control unit 32 and is configured to pull the welding wire B. The feeding unit 31 includes a feeding motor 311, a feeding roll 312, and a pressure 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 (a 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 (a driving unit 321 described later) controls the rotation speed of the feed motor 311 by adjusting the pulse width of the driving signal by, for example, pulse width modulation.

  The feed roll 312 is attached to the rotation shaft of the feed motor 311, and rotates by receiving torque generated by the feed motor 311. The method for 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 that pulls the welding wire B. Accordingly, the welding wire B is pulled by driving the feed motor 311.

  The pressure roll 313 is disposed so as to face the feeding roll 312 with the welding wire B interposed therebetween, and pressurizes the welding wire B toward the feeding roll 312. Thereby, the welding wire B is fed according to the rotation of the feeding roll 312.

  The control unit 32 is realized by, for example, a microcomputer and controls the welding torch 3. The control unit 32 performs a predetermined process according to the operation signal input from the operation unit 33. Further, the control unit 32 communicates with the welding power source 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 a corresponding process, a display unit 34. Control the display on the screen. 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 source device 1. As shown in FIG. 2, the control unit 32 includes a drive unit 321, a current sensor 322, and an arrival detection unit 323.

The drive unit 321 controls the feeding of the welding wire B by controlling the driving of the feeding unit 31. 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 source device 1. An encoder (not shown) is attached to the feed motor 311, and the control unit 32 detects the rotational 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. Drive unit 321, rotational speed of the feed motor 311 is detected by adjusting the drive signal to match the rotational speed corresponding to the speed command S _2, performs feedback control. The method for detecting the rotational 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 unit 21 of the wire feeding device 2, and after the welding wire B reaches the feeding unit 31 of the welding torch 3, the feeding unit 21 and the feeding unit 31 are used. Be sent. The feeding motor 311 of the feeding unit 31 is in an unloaded state until the welding wire B reaches the feeding unit 31, but the welding wire B reaches the feeding unit 31 (strictly, the feeding roll 312). After that, it takes a load. Accordingly, the current value of the drive signal output from the drive unit 321 to the feed motor 311 changes before and after the welding wire B reaches the feed unit 31. The arrival detection unit 323 reaches the feeding unit 31 from the change in the current value of the drive signal output to the feeding motor 311 based on the detected current value I ₂ input from the current sensor 322. Detect that. Specifically, when the arrival detection unit 323, which compares the current detection value I ₂ and the current threshold I _2th inputted from the current sensor 322, a current detection value I ₂ becomes equal to or greater than the current threshold I _2th, It is determined that the welding wire B has reached the feeding unit 31. The current threshold value I _2th is the current detection value I _2L when the feed motor 311 is in a no-load state (before the welding wire B reaches the feed unit 31), and when the load is applied to the feed motor 311 ( It is set as a value between the current detection value I _2H (when the feeding part 31 is feeding the welding wire B).

In the present embodiment, the current detection value I _2L when there is no load is about 0.3 A, and the current detection value I _2H when the load is applied is about 0.6 _A. It is set to 0.45A. The current threshold value I _2th is not limited. The _{closer the} current threshold I _2th is to the current detection value I _2L , the earlier the arrival of the welding wire B can be detected, but the possibility of erroneous detection of arrival increases. On the other hand, the closer the current threshold I _2th is to the current detection value I _2H , the more erroneous detection of arrival can be suppressed, but the timing for detecting arrival is delayed. The current threshold I _2th may be set as appropriate 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, the arrival detection unit 323 generates an arrival detection signal. The arrival detection signal is transmitted to the welding power source device 1.

  The display unit 34 performs various displays, and includes a display (not shown) that is a liquid crystal display device, for example. 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 units, and outputs the operation of each operation unit by the operator to the control unit 32 as an operation signal. As the operation means, there are a torch switch, an inching button and an operation button which are not shown. Note that the operation unit 33 may include other operation means.

  The torch switch is an operation 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 for instructing the start of welding and transmits the signal to the welding power source apparatus 1. The welding power source apparatus 1 that has received the signal starts feeding the welding wire B and starts outputting welding power. Further, when the on operation is released, an operation signal is output to the control unit 32. The control unit 32 to which the operation signal is input generates a signal for instructing the end of welding and transmits the signal to the welding power source device 1. The welding power supply device 1 that has received the signal stops feeding the welding wire B and stops outputting welding power. Thereby, welding is performed only while the torch switch is pressed. In addition, transmission of the on / off operation of the torch switch may be performed by a change in the level of an electric signal via the control line.

  The inching button is an operation means for accepting an inching operation start / stop operation. When the inching button 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 for instructing to start inching and transmits the signal to the welding power source apparatus 1. The welding power source apparatus 1 that has received the signal starts feeding the welding wire B. Further, when the on operation is released, an operation signal is output to the control unit 32. The control unit 32 to which the operation signal is input generates a signal for instructing the end of inching and transmits the signal to the welding power source apparatus 1. The welding power supply device 1 that has received the signal stops feeding the welding wire B. Thereby, the welding wire B is fed only while the inching button is pressed. The operation method of the inching button is not limited. It may be set so that the feeding of the welding wire B and the feeding stop are switched each time the inching button is pressed. Note that the transmission of the on / off operation of the inching button may be performed by a change in the level of an electric signal via the control line. Further, the inching button may be provided on the welding power supply device 1 or the wire feeding device 2. In the present embodiment, even when the feeding stop of the welding wire B is not instructed, the feeding of the welding wire B is stopped when the welding wire B reaches the feeding unit 31 of the welding torch 3. Details of inching will be described later.

  The operation buttons are operation means for performing operations for switching screens and changing various setting values. The operation buttons include, for example, an upper button, a lower button, a left button, and a right button. When each button is pressed, a corresponding operation signal is output to the control unit 32, and the control unit 32 performs a 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. When the upper or lower button is pressed, the setting value displayed on the display is changed. The In the present embodiment, the operation of the inching button can be accepted when the mode is switched to the “inching mode” by the operation of the left button or the right button. Note that 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, there is no need 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. 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.

  Inching is performed, for example, as a preparatory work after attaching a new wire reel 23 to the wire feeder 2. The operator manually guides the tip of the welding wire B drawn from the wire reel 23 to the feed roll 212 by inserting the tip of the welding wire B through the inlet liner and the inlet guide of the wire feeding device 2.

Then, the operator presses the inching button of the welding torch 3. In response to pressing of the inching button, the welding power source device 1 starts feeding the welding wire B. Specifically, welding power supply device 1 (control unit 11) transmits speed command S ₁ to control unit 22 of wire feeding device 2 and transmits speed command S ₂ to control unit 32 of welding torch 3. Control unit 22 (drive unit 221) based on the speed command S ₁ received, to control the rotational speed of the feed motor 211. Accordingly, the welding wire B is fed at a speed corresponding to the speed command S _1. The control unit 32 (drive unit 321) based on the speed command S ₂ received, to control the rotational speed of the feed motor 311.

Welding power supply apparatus 1 (the controller 11), gradually increasing the speed command S ₁ from "0" to the speed command S _IH that is set. Further, the speed command S ₂ is gradually increased from “0” to obtain the set speed command S _2H . The reason why the speed commands S ₁ and S ₂ are gradually increased is to suppress the overshoot of the current value of the drive signal generated by abrupt increase. If overshoot does not become 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 source device 1 stops feeding the welding wire B. Specifically, the welding power source device 1 (control unit 11) transmits a speed command S ₁ to be transmitted to the control unit 22 of the wire feeding device 2 and a speed command S ₂ to be transmitted to the control unit 32 of the welding torch 3. Decrease gradually to “0”. Thereby, feeding of 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 feeding the welding wire B, when the welding wire B reaches the feeding unit 31 of the welding torch 3, feeding of the welding wire B is stopped. This automatic stop of feeding will be described below with reference to FIG.

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

When inching is started at time t0, the speed commands S ₁ and S ₂ gradually increase. 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 from the drive unit 321 to the feeding motor 311 and the detected current value I ₂ becomes _{equal to} or greater than the current threshold value I _2th (see FIG. 3C). ). Therefore, the arrival detection unit 323 does not perform detection until a predetermined time T1 has elapsed from the start of feeding (between time t0 and predetermined time t4). Then, the welding wire B is fed at a constant speed, and the feeding 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 an unloaded 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 feeding amount of the welding wire B becomes L1 at time t1 (see FIG. 3 (f)), when the tip of the welding wire B reaches the feeding unit 31 (feeding roll 312), the feeding is performed. Tension is gradually applied to the welding wire B that has been slightly bent in the path (see FIG. 3E). In response to this, a load is applied to the feed motor 311 and the current detection value I ₂ increases (see FIG. 3C).

When the current detection value I ₂ becomes _{equal to} or greater than the current threshold value I _2th 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 source apparatus 1 (see FIG. 3D). The welding power source apparatus 1 that has received the arrival detection signal decreases the speed commands S ₁ and S ₂ to “0” (see FIGS. 3A and 3B). Thereby, the feeding motor 211 and the feeding motor 311 are stopped, and the feeding of the welding wire B is stopped (see FIG. 3F). At this time, the tension applied to the welding wire B decreases to “0” (see FIG. 3E), and the current detection value I ₂ decreases to “0” accordingly (FIG. 3C). )reference). Note that the feeding of the welding wire B continues from when the tip of the welding wire B reaches the feeding roll 312 (time t1) to when the arrival detection unit 323 detects arrival (time t2). However, this time (t2-t1) is sufficiently smaller than the entire feeding time, and the feeding amount of the welding wire B fed during this time is very small (for example, about several centimeters).

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 automatic stopping has been performed. The operator can know that the automatic stop has occurred by viewing the display. In addition, the method of notifying an operator of an automatic stop is not limited. You may notify by the sound from the speaker which is not shown in figure, and you may notify by lighting the lamp which is not shown in figure. Moreover, you may notify by vibrating the welding torch 3. The control unit 32 may detect the automatic stop by arrival detection signal output by the arrival detection unit 323, the automatic communication signal from the welding power source device 1 (signal indicating the speed command S ₂ or automatic stop) 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 source apparatus 1 sets the speed command S ₁ to a speed command S _1L that makes the feeding speed slower than the speed command S _1H , and makes the speed command S ₂ slower than the speed command S _2H. It becomes speed command _S2L which becomes. In this embodiment, the speed command S _1H is set to a speed at which the welding wire B is fed at about 15 to 20 m per minute, and the speed command S _1L is set at a speed at which the welding wire B is fed about a few meters per minute. The speed command S _2H (S _2L ) is set to a speed several percent larger than the speed command S _1H (S _1L ). The speed commands S _1H , S _1L , S _2H , 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 centimeters), the required time increase is small even if the feeding speed is slow. On the other hand, since the feeding speed becomes slow, the operator can easily stop feeding at an appropriate timing. Note that the control unit 11 does not automatically change the speed commands S ₁ and S ₂ , but the operator changes the speed commands S ₁ and S ₂ by operating the operation unit 33 of the welding torch 3. Also 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 inching control processing performed by the control unit 11 of the welding power source apparatus 1, and FIG. 4B shows arrival detection processing 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 source device 1 is activated. This process may be executed only when the welding torch 3 is switched to the “inching mode”. First, the control part 11 discriminate | determines whether the inching start was instruct | indicated (S1). Specifically, the control unit 11 determines whether or not a signal instructing to start inching is received from the control unit 32 of the welding torch 3. When the inching start is not instructed (S1: NO), the process returns to step S1 and the determination is repeated. That is, the control unit 11 stands by until an inching start is instructed. When inching start is instructed (S1: YES), the control unit 11 instructs to start feeding the welding wire B (S2). Specifically, the control unit 11 transmits the speed command S ₁ to the wire feeder 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 part 11 discriminate | determines whether completion | finish of the inching was instruct | indicated (S3). Specifically, the control unit 11 determines whether or not a signal instructing the end of inching is received from the control unit 32 of the welding torch 3. When the inching end is not instructed (S3: NO), the control unit 11 determines whether or not an arrival detection signal is 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 determinations of steps S3 and S4 are repeated. That is, the control unit 11 stands by until an inching end is instructed or an arrival detection signal is received. When the inching end is instructed (S3: YES) or the arrival detection signal is received (S4: YES), the control unit 11 instructs to stop feeding the welding wire B (S5). Specifically, the control unit 11 transmits the speed command S ₁ to the wire feeder 2 while decreasing 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 stands by until an instruction to start inching is given.

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 it has received a speed command S ₁ from the control unit 11 (S11). When not receiving (S11: NO), it returns to step S11 and repeats the said determination. That is, the control unit 32 waits until it receives a speed command S _1. Upon receiving the speed command S ₁ (S11: YES), the control unit 32 waits a predetermined time has elapsed T1 (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 does not detect until the overshoot converges. I have to. During this time, the control unit 32 increases the rotation speed of the feed motor 311 according to the speed command S ₁ received from the control unit 11.

After the predetermined time T1 has elapsed (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 I _2th (S14). If the current detection value I ₂ is less than the current threshold I _2th (S14: NO), the process returns to S13. On the other hand, when the current detection value I ₂ is _{equal to} or greater than the current threshold I _2th (S14: YES), the arrival detection unit 323 generates an arrival detection signal. The control unit 32 transmits an arrival detection signal to the welding power source device 1 (S15). Next, the control unit 32 waits for a predetermined time T2 to elapse (S16). During this time, the control unit 32 decreases the rotation speed of the feed motor 311 according to the speed command S ₁ received from the control unit 11 and stops the feed motor 311. Then, the process returns to S11, the control unit 32 waits for the reception speed command S _1.

  Note that 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 effect of welding system A1 is demonstrated.

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 is _{equal to} or greater than the current threshold value I _2th. Then, the arrival detection signal is transmitted to the welding power source apparatus 1. When receiving the arrival detection signal, the control unit 11 of the welding power source apparatus 1 decreases the speed commands S ₁ and S ₂ to “0”. Thereby, 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 released from the troublesomeness such as pressing and holding the inching button for a long time, or cutting the excessive welding wire B that has come out of the tip of the welding torch. Also, a conventional welding torch provided with a feed motor is provided with a current sensor 322 for overcurrent protection. Since the arrival detection unit 323 makes a determination based on the current detection value I ₂ detected by the current sensor 322, the welding system A1 does not need to include a new detection mechanism for detecting the welding wire B. Therefore, it can suppress that the structure of each apparatus becomes complicated, and can suppress the 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 automatic stopping has been performed. Thereby, the operator can know that it stopped automatically by seeing the display.

  Further, according to the present embodiment, the welding torch 3 includes the feeding unit 31. Since the distance from the feeding unit 31 to the tip of the welding torch 3 is short, the time for feeding the welding wire B fed to the feeding unit 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 welding wire B by comparing the current detection value I ₂ with the current threshold I _2th has been described, but the present invention is not limited to this. For example, a calculation unit that calculates a differential value of the current detection value I ₁ output by the current sensor 322 is provided, and the arrival detection unit 323 compares the differential value calculated by the calculation unit with a threshold value to determine the arrival of the welding wire B. You may judge. In this case, the arrival of the welding wire B can be detected earlier than in the case where the current detection value I ₂ is compared with the current threshold I _2th , but the possibility of erroneous detection of arrival is increased. 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 I _2th is a fixed value has been described, but the present invention is not limited to this. The greater the speed command S _2H , the greater the detected current value I _2L when the feed motor 311 is in the no-load state. Therefore, when the current threshold value I _2th is a fixed value, the difference between the current threshold value I _2th and the current detection value I _2L is small when the speed command S _2H is large. Then, the possibility that the arrival detection unit 323 erroneously detects the arrival of the welding wire B is increased. In order to prevent this, the arrival detection unit 323 may change the current threshold I _2th according to the speed command S _2H . By increasing the current threshold value I _2th as the speed command S _2H increases, the difference between the current threshold value I _2th and the detected current value I _2L can be suppressed, and the arrival detection unit 323 can increase the possibility of erroneous detection. Can be reduced. In the present embodiment, the speed command S _2H corresponds to the “command value of the welding wire feeding speed” of the present invention. The arrival detection unit 323 may change the current threshold 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 welding wire B based on the current detection value I ₂ has been described, but the present invention is not limited thereto. For example, when the control unit 32 includes a sensor that detects electric power output from the driving unit 321 to the feed motor 311, the arrival detection unit 323 determines the welding wire based on the electric power detection value detected by the sensor. The arrival of B may be determined. Moreover, when the control part 32 is provided with the sensor which detects the voltage output to the feed motor 311 from the drive part 321, the arrival detection part 323 is based on the voltage detection value which the said sensor detected. The arrival of B may be determined. 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 rotation 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) when 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. Note that 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 speed of the feed roll 312 during no load is higher than the tangential speed of the feed roll 212. Further, after reaching the wire, it is necessary to take measures to prevent the welding wire B from buckling. As the countermeasure, for example, a method of switching the speed control from the constant current control, but a method for reducing the speed command S ₁ is considered, 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 thereto. For example, the current sensor 322 may detect a current value of a current supplied to the drive unit 321 from a power source (not shown) included in the welding torch 3. 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 in the same manner, so that the arrival of the welding wire B can be detected based on the current value detected by the current sensor 322. Also in these cases, it can be said that the current sensor 322 detects the current supplied to the feeding 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, the current sensor 322, and the arrival detection unit 323 has been described, but the present invention is not limited thereto. The control unit 11 may include a drive unit 221, a drive unit 321, a current sensor 322, and an arrival detection unit 323. That is, the welding power supply device 1 may be configured to control the rotational 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, detection of the current value of the drive signal by the current sensor 322 and determination by the arrival detection unit 323 can be performed inside the welding power source apparatus 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 thereto. The drive unit 221 may control the torque of the feed motor 211.

  In this embodiment, although the case where the feeding unit 21 sends out the welding wire B by the rotation of the feeding roll 212 has been described, the present invention is not limited thereto. The feeding unit 21 may send out the welding wire B by other methods.

  In the present embodiment, the case where feeding of the welding wire B is stopped when the arrival of the welding wire B is detected (automatic stop) has been described, but the present invention is not limited thereto. 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 display on the display of the display unit 34, sound 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]
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 modification. The modification does not stop the feeding of the welding wire B when the welding wire B reaches the feeding unit 31 but stops the feeding of the welding wire B to the tip of the welding torch 3. It is.

  FIG. 5 shows inching control processing performed by the control unit 11 according to the modification. In addition, since the arrival detection process which the control part 32 which concerns on a modification is the same as that of the flowchart shown in FIG.4 (b), description and description are abbreviate | 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. The flowchart shown in FIG. 5 is that the process of step S6 and step S7 is added before the process proceeds to step S5 when the control unit 11 receives an arrival detection signal in step S4 (S4: YES). This is different from the flowchart shown in FIG.

When the control unit 11 receives the arrival detection signal (S4: YES), the control unit 11 instructs to reduce the feeding speed of the welding wire B (S6). Specifically, the control unit 11 transmits the speed command S ₁ to the wire feeder 2 while decreasing 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 a predetermined time T3 to elapse (S7), and then instructs to stop feeding the welding wire B (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 such that the feed amount from when the tip of the welding wire B reaches the feed roll 312 until arrival is detected by the arrival detection unit 323, the feed amount during deceleration in step S6, and Also, the feeding amount at the time of deceleration in the feeding stop in step S5 is considered. The predetermined time T3 corresponds to the “low speed feeding time” of the present invention. 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 illustrated 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-described process.

  FIG. 6 is a timing chart for explaining automatic stop of feeding according to the modification. The timing chart shown in FIG. 6 is the same as the timing chart shown in FIG. 3 at time t0 to time t2, and thus the description thereof is omitted.

When the current detection value I ₂ becomes _{equal to} or greater than the current threshold value I _2th 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 the arrival. A signal is transmitted to the welding power source apparatus 1 (see FIG. 6D). Welding power supply apparatus 1 which has received the arrival detection signal (see FIG. 6 (a)) the speed command S ₁ is decreased from S _IH to S _1L, the speed command S ₂ is decreased from S _2H to S _2L (See FIG. 6 (b)). Thereby, the feeding motor 211 and the feeding motor 311 are decelerated, and the feeding speed of the welding wire B is reduced (see FIG. 6F). The tension applied to the welding wire B increases to a predetermined value and then continues to the predetermined value (see FIG. 6 (e)). Current detection value I ₂ accordingly be increased until the current detection value I _2H, then continues the current detection value I _2H (see Figure 6 (c)).

When the predetermined time T3 elapses from time t2 and time t3 is reached, the welding power source apparatus 1 decreases the speed commands S ₁ and S ₂ to “0” (see FIGS. 6A and 6B). . Thereby, the feeding motor 211 and the feeding motor 311 are stopped, and the feeding of the welding wire B is stopped (see FIG. 6F). At this time, the tension applied to the welding wire B decreases to “0” (see FIG. 6E), and the current detection value I ₂ decreases to “0” accordingly (FIG. 6C). )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 automatic stop has been performed. The operator can know that the automatic stop has occurred by viewing 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 the fact on the display of the display unit 34. In this case, the operator can know in advance that the automatic stop will soon be performed by viewing the display.

Note that the welding power source apparatus 1 may not change the speed command S ₁ (S ₂ ) from S _1H (S _2H ) even after the welding wire B reaches the feeding unit 31 at time t2.

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

[Second Embodiment]
FIG. 7 is a diagram for explaining a 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 those of the welding system A1 (see FIG. 2) are denoted by the same reference numerals, and redundant description is 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 an abnormality is detected 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 detector 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 corresponding to the rotation speed of the feed motor 211. The speed detector 222 detects the rotational 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 feeding speed to the feeding amount calculation unit 223. Note that the wire feeding device 2 according to the first embodiment is also provided with a speed detection unit 222 although not shown.

  The feed amount calculation unit 223 receives 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. In addition, the calculation method of feeding amount is not limited. The control unit 22 transmits the feed amount from the start of inching calculated by the feed amount calculation unit 223 to the welding power source apparatus 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 determines 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. Detect an abnormality in the feeding configuration. When there is no abnormality, when the feeding amount from the start of inching becomes the length L1 of the feeding path from the feeding unit 21 (feeding roll 212) to the feeding unit 31 (feeding roll 312), An arrival detection signal should be received. Therefore, if the arrival detection signal is not received even if the feeding amount from the inching start exceeds L1, or if the arrival detection signal is received before the feeding amount from the inching start reaches L1, there is an abnormality. It 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 feeding amount from the start of the inching is equal to or greater than the first predetermined value (L1 + α). In this case, 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 is considered. α (> 0) is an adjustment value for preventing erroneous detection of abnormality. In addition, the abnormality detection unit 111 determines that there is an abnormality when the arrival detection signal is received when the feeding amount from the start of the inching is equal to or smaller than the second predetermined value (L1-β). In this case, an abnormality in the feeding unit 31 or the drive unit 321, an abnormality in 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 detection unit 111 detects an abnormality, the control unit 11 stops feeding the welding wire B and notifies that an 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 abnormality signal includes information indicating the type of abnormality. The control unit 32 that has received the abnormality signal displays on the display of the display unit 34 a description according to the occurrence of the abnormality and a description according to the type of abnormality. In addition, the abnormality notification method is not limited. Moreover, 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. And when abnormality is detected, a failure and an accident can be prevented by stopping feeding of welding wire B. In addition, when an abnormality is detected, the operator can be notified of the occurrence of the abnormality. Also in this embodiment, it is not necessary to provide a new detection mechanism for detecting the welding wire B.

[Third Embodiment]
8 and 9 are diagrams for explaining a 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 the welding wire B feeding. In these drawings, elements that are the same as or similar to the welding system A1 (see FIGS. 2 and 3) are assigned the same reference numerals, and redundant descriptions are omitted.

  The welding system A3 according to this 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 not described 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 an arrival 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 feeding motor 211 and the like from overcurrent based on the current detection value I ₁ detected by the current sensor 224. In addition, 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 unit 21 of the wire feeding device 2, and after the welding wire B reaches the feeding unit 31 of the welding torch 3, the feeding unit 21 and the feeding unit 31 are used. Be sent. The feeding motor 211 of the feeding unit 21 is subjected to a large load until the welding wire B reaches the feeding unit 31, but the welding wire B is applied to the feeding unit 31 (strictly, the feeding roll 312). The load is reduced after reaching. Accordingly, the current value of the drive signal output from the drive unit 221 to the feed motor 211 changes before and after the welding wire B reaches the feed unit 31. The arrival detection unit 225 reaches the feeding unit 31 from the change in the current value of the drive signal output to the feeding motor 211 based on the detected current value I ₁ input from the current sensor 224. Detect that.

FIG. 9C shows a 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. Accordingly, the feeding resistance of the welding wire B increases little by little, so the load applied to the feeding motor 211 also increases little by little. In response to this, the current detection value I ₁ also increases little by little. 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 decreases. 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, when 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 a current differential value. Then, the arrival detection unit 225 compares the calculated current differential value with the differential threshold value, and determines that the welding wire B has reached the feeding unit 31 when the current differential value is equal to or less than the differential threshold value. In the present embodiment, the differential threshold is set to “0”. The differential threshold is not limited. The arrival detection unit 225 may detect that the welding wire B has reached the feeding unit 31 by other methods.

According to this embodiment, the arrival detection unit 225 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 is equal to or less than the differentiation threshold. It is determined that the arrival detection signal is transmitted to the welding power source apparatus 1. When receiving the arrival detection signal, the control unit 11 of the welding power source device 1 stops feeding the welding wire B. Therefore, the operator is released from the troublesomeness such as pressing and holding the inching button for a long time, or cutting the excessive welding wire B that has come out of the tip of the welding torch. The conventional wire feeder is also provided with a current sensor 224 for overcurrent protection. Since the arrival detection unit 225 makes a determination based on the current detection value I ₁ detected by the current sensor 224, the welding system A3 does not need to include a new detection mechanism for detecting the welding wire B. Therefore, it can suppress that the structure of each apparatus becomes complicated, and can suppress the increase in manufacturing cost.

  In the third embodiment, the control unit 32 of the welding torch 3 may include an 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 feeding may be stopped when both the arrival detection unit 225 and the arrival detection unit 323 detect arrival, or when either the arrival detection unit 225 or the arrival detection unit 323 detects arrival. May be stopped.

[Fourth Embodiment]
FIGS. 10 and 11 are diagrams for explaining a welding system A4 according to the fourth embodiment. FIG. 10 is a schematic diagram showing an overall configuration of the welding system A4. FIG. 11 is a block diagram showing a functional configuration of the welding system A4. In these drawings, the same or similar elements as those of the welding system A1 (see FIGS. 1 and 2) are denoted by the same reference numerals, and redundant description is omitted. In addition, in FIG. 11, description of the internal structure of welding torch 3 'is abbreviate | 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 pull-side feeding device, and further includes a pull feeder 9 serving as a pull-side feeding device instead. .

  The welding torch 3 ′ does not include the feeding unit 31, the drive unit 321, the current sensor 322, and the arrival detection unit 323 in the welding torch 3 according to the first embodiment (see FIG. 2). 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, thereby reducing the feeding resistance of the welding wire B. As shown in FIG. 10, the pull feeder 9 is disposed near 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. The pull feeder 9 is connected to the welding torch 3 ′ by a torch cable 39 ′ having the same configuration as the torch cable 39. The length of the torch cable 39 is, for example, about several tens of meters, whereas the length of the torch cable 39 'is, for example, about several meters. The pull feeder 9 and the wire feeder 2 communicate with each other via a communication line (not shown) provided inside the torch cable 39. The pull feeder 9 and the welding torch 3 ′ communicate with each other via a communication line (not shown) provided inside the torch cable 39 ′. The pull feeder 9 and the welding power source device 1 communicate with each other through the wire feeding device 2. Note that the pull feeder 9 and the welding power source 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 and is configured to pull the welding wire B. The feeding unit 91 includes a feeding motor 911, a feeding roll 912, and a pressure roll 913.

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

  The feed roll 912 is attached to the rotating shaft of the feed motor 911, and rotates by receiving torque generated by the feed motor 911. The method for 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 feeding roll 912, and the torque of the feeding roll 912 is converted into a tangential force that pulls the welding wire B. Therefore, the welding wire B is pulled by driving the feed motor 911.

  The pressure roll 913 is disposed so as to face the feeding roll 912 with the welding wire B interposed therebetween, and pressurizes the welding wire B toward the feeding roll 912. Thereby, the welding wire B is fed according to the rotation of the feeding roll 912.

  The control unit 92 is realized by, for example, a microcomputer 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 source apparatus 1. The control unit 92 includes a drive unit 921, a current sensor 922, and an arrival detection unit 923.

The driving unit 921 controls the feeding of the feeding wire 91 to control the feeding 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 S ₂ received from the control unit 11 of the welding power source device 1. An encoder (not shown) is attached to the feed motor 911, and the control unit 92 detects the rotational speed of the feed motor 911 from a pulse signal input from the encoder. The encoder may be an optical encoder or a magnetic encoder. Drive unit 921, the rotation speed of the detected feed motor 911 adjusts the driving signal to match the rotational speed corresponding to the speed command S _2, performs feedback control. The method for detecting the rotational 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 controller 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 welding wire B is first fed by the feeding unit 21 of the wire feeding device 2, and after the welding wire B reaches the feeding unit 91 of the pull feeder 9, the welding wire B is fed by the feeding unit 21 and the feeding unit 91. Be paid. The feeding motor 911 of the feeding unit 91 is in an unloaded state until the welding wire B reaches the feeding unit 91, but the welding wire B reaches the feeding unit 91 (strictly, the feeding roll 912). After that, it takes a load. Therefore, the current value of the drive signal output from the drive unit 921 to the feed motor 911 changes before and after the welding wire B reaches the feed unit 91. The arrival detection unit 923 has reached the feeding unit 91 from the change in the current value of the drive signal output to the feeding motor 911 based on the detected current value I ₂ input from the current sensor 922. Detect that. A specific detection method is the same as that of the arrival detection unit 323 according to the first embodiment. When arrival detection unit 923 detects that welding wire B has reached feeding unit 91, arrival detection unit 923 generates an arrival detection signal. The arrival detection signal is transmitted to the welding power source device 1.

  In the present embodiment, the feeding unit 21 corresponds to a “first feeding unit” of the present invention, and the feeding unit 91 corresponds to a “second feeding unit” of the present invention. 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 is _{equal to} or greater than the current threshold value I _2th. Then, the arrival detection signal is transmitted to the welding power source apparatus 1. When receiving the arrival detection signal, the control unit 11 of the welding power source device 1 stops feeding the welding wire B. Therefore, the operator is released from the troublesomeness such as pressing and holding the inching button for a long time, or cutting the excessive welding wire B that has come out of the tip of the welding torch. The conventional pull feeder also includes 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 include a new detection mechanism for detecting the welding wire B. Therefore, it can suppress that the structure of each apparatus becomes complicated, and can suppress the increase in manufacturing cost.

  Furthermore, according to the present embodiment, the welding torch 3 ′ does not need to have a configuration for feeding the welding wire B, and thus can be reduced in size and weight.

  In the fourth embodiment, the welding torch 3 ′ may include the feeding unit 31, the driving unit 321, the current sensor 322, and the arrival detection unit 323 (that is, the welding torch 3). In the case of this configuration, when the welding wire B reaches the feeding portion 91 of the pull feeder 9 before the welding wire B reaches the feeding portion 31 of the welding torch 3 and automatically stops, the automatic stopping is soon to be performed. Notification can be made in advance. Alternatively, 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 said 1st-4th embodiment, although the case where the welding wire B was supplied in welding system A1-A4 was demonstrated, it is not restricted 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 spray 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 varied in design in various ways.

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: Pressure roll 22: Control unit 221: Drive unit 222: Speed detection unit 223: Feed amount calculation unit 224: Current sensor 225: Arrival detection unit 23: Wire reel 3, 3 ': Welding torch 31: Feed unit 311: Feed motor 312: Feed roll 313: Pressure roll 32: Control unit 321: Drive unit 322: Current sensor 323: Arrival detection unit 33: Operation unit 34: Display unit 9: Pull feeder 91: Feed unit 911: Feed motor 912: Feed roll 913: Pressure roll 92: Control unit 921: Drive unit 922: Current sensor 923: Arrival detection unit 39, 39 ': Torch cable 41, 42: Power Cable 5: Power transmission line 6: Gas cylinder 7: Gas pipe 8: Communication line B: Welding wire P: Power system W: Work piece

Claims (10)

A first feeding section for feeding a wire;
A second feeding unit that is arranged on the feeding direction side of the wire from the first feeding unit, has a feeding motor, and feeds the wire by rotation of the feeding motor;
A control unit for controlling the first feeding unit and the second feeding unit;
With
The controller is
An electrical signal supplied to the feed motor, or a sensor for detecting the rotational speed of the feed motor;
An arrival detection unit that detects that the wire has reached the second feeding unit, based on a detection value detected by the sensor;
Comprising
A wire feeding system characterized by that. A first feeding unit that has a feeding motor and feeds the wire by rotation of the feeding motor;
A second feeding unit that is arranged closer to the feeding direction of the wire than the first feeding unit and feeds the wire;
A control unit for controlling the first feeding unit and the second feeding unit;
With
The controller is
A sensor for detecting an electrical signal supplied to the feeding motor;
An arrival detection unit that detects that the wire has reached the second feeding unit, based on a detection value detected by the sensor;
Comprising
A wire feeding system characterized by that. The arrival detection unit
A comparison unit that compares the detected value with a threshold value;
Based on the comparison result in the comparison unit, the arrival of the wire is detected.
The wire feeding system according to claim 1 or 2. The arrival detection unit
A calculation unit for calculating a differential value of the detected value;
A comparison unit for comparing the differential value with a threshold;
With
Based on the comparison result in the comparison unit, the arrival of the wire is detected.
The wire feeding system according to claim 1 or 2. The arrival detection unit changes the threshold according to a command value of the wire feeding speed,
The wire feeding system according to claim 3 or 4. The electrical signal is a current;
The wire feeding system according to any one of claims 1 to 5. The control unit stops the first feeding unit and the second feeding unit when the arrival detection unit detects the arrival of the wire.
The wire feeding system according to any one of claims 1 to 6. When the arrival detection unit detects the arrival of the wire, the control unit decreases the feeding speed of the wire by the first feeding unit and the second feeding unit, and after the feeding speed is lowered When the predetermined low speed feeding time has elapsed, the first feeding unit and the second feeding unit are stopped.
The wire feeding system according to any one of claims 1 to 6. Welding torch,
A welding power supply for supplying 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 comprising: The second feeding unit is disposed on the welding torch.
The welding system according to claim 9.

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