Welding apparatus and welding monitoring device

Abstract

To provide a monitoring device and a welding apparatus capable of accurately monitoring the welding state of each weld portion even when a plurality of locations on the same welding object are welded simultaneously.SOLUTION: A welding apparatus comprises: a first welder that includes a first torch member and a welding electrode projecting from a tip end of the first torch member, and welds a first weld portion of a welding object; a second welder that includes a second torch member and a welding electrode projecting from a tip end of the second torch member, and welds a second weld portion of the welding object; a first sensor that is installed on an installation surface of the first torch member and detects an elastic wave transmitted to the first torch member; a second sensor that is installed on an installation surface of the second torch member and detects an elastic wave transmitted to the second torch member; a first processing circuit that determines a welding state of the first weld portion on the basis of a detection signal sent from the first sensor; and a second processing circuit that determines a welding state of the second weld portion on the basis of a detection signal sent from the second sensor.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to a welding device and a welding monitoring device. [Background technology]

[0002] When melting, solidification, plastic deformation, fracture, and phase transformation occur in a structure during welding, the rapid release of energy can cause phenomena in which unsteady elastic waves, known as acoustic emissions (hereinafter simply referred to as "AE"), are generated in the welded object.Technology is known that uses an AE sensor to detect the elastic waves, known as AE waves, generated by such phenomena and analyzes their waveforms to determine the weld condition and weld quality of the welded object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-179363 [Patent Document 1] Patent Publication No. 2021-45782 [Patent Document 2] Patent No. 4120254 [Patent Document 3] Patent No. 3114830 Summary of the Invention [Problem to be solved by the invention]

[0004] The welding condition is monitored by detecting AE waves generated during arc welding with an AE sensor and converting them into an electrical signal. In this case, the AE sensor is installed on the side of the workpiece. When multiple locations on a single workpiece are welded simultaneously, the AE waves generated at the multiple welds are mixed and superimposed and input to the AE sensor. For this reason, it is difficult to accurately monitor the welding condition of each weld using detection, recording, and judgment based on the detection signal from the AE sensor installed on the workpiece. The embodiments of the present invention have been made in consideration of the above circumstances, and an object of the present invention is to provide a welding monitoring device and a welding device that can accurately monitor the welding state of each weld, even when multiple locations on the same welding object are welded simultaneously. [Means for solving the problem]

[0005] According to an embodiment, the welding device comprises: a first welding machine for welding a first welded portion of the workpiece, the first welding machine including: an arm; a first torch member made of a metal material having a base end connected to the arm, a tip end facing the workpiece, and a flat installation surface; a welding electrode inserted into the first torch member and protruding from the tip end; and a power supply unit for applying a voltage between the welding electrode and the workpiece; a second welding machine including: an arm; a second torch member made of a metal material having a base end connected to the arm, a tip end facing the work-pieces, and a flat installation surface; a welding electrode inserted into the second torch member and protruding from the tip end; and a power supply unit applying a voltage between the welding electrode and the work-pieces, the second welding machine welding a second weld portion different from the first weld portion of the work-pieces; The monitoring device includes a first sensor installed on the installation surface of the first torch member and detecting elastic waves transmitted to the first torch member, a second sensor installed on the installation surface of the second torch member and detecting elastic waves transmitted to the second torch member, a first processing circuit that determines the welding condition of the first welded portion based on the detection signal sent from the first sensor, and a second processing circuit that determines the welding condition of the second welded portion based on the detection signal sent from the second sensor. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a plan view schematically showing a welding device according to an embodiment. [Figure 2] FIG. 2 is a diagram showing a torch member and a monitoring device of the welding apparatus. [Figure 3]FIG. 3 is a perspective view showing the base end portion of the torch member and the AE sensor. [Figure 4] FIG. 4 is a flowchart showing a monitoring operation of a welded portion in the welding device. [Figure 5] FIG. 5 is a diagram showing (a) welding timing, (b) a detection signal of a first AE sensor, and (c) a detection signal of a second AE sensor of the welding device. DETAILED DESCRIPTION OF THE INVENTION

[0007] A welding device according to an embodiment of the present invention will be described below with reference to the drawings. The disclosure is merely an example, and appropriate modifications that are easily conceivable by those skilled in the art while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment for the sake of clarity, but these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the previous drawings may be designated by the same reference numerals, and detailed descriptions may be appropriately simplified or omitted.

[0008] (Embodiment) FIG. 1 is a plan view schematically showing a welding device according to an embodiment. As shown in the figure, the welding apparatus 100 includes a plurality of welding machines that weld any portion of the workpiece 10, a monitoring device 30 that monitors the welding status of each welding machine, and a controller 60 that controls the operation of the plurality of welding machines and the operation of the monitoring device. In this embodiment, welding apparatus 100 includes a first welder 20A that welds a first weld zone WA of workpiece 10, such as a structure, and a second welder 20B that welds a second weld zone WB of workpiece 10 that is different from first weld zone WA. First weld zone WA and second weld zone WB correspond to parts of the same workpiece 10, each extending linearly or curvedly, and positioned apart from each other. Workpiece 10 is, for example, a metal plate made of steel, stainless steel, or the like, but is not limited thereto.

[0009] The first welding machine 20A has a base 22, a robot arm 24 rotatably mounted on the base 22, a torch member 26 (sometimes referred to as the first torch member) attached to the tip of the robot arm 24, and a power supply unit 28 that applies a drive voltage between the welding electrode described below and the workpiece 10. Base 22 may be either fixed or self-propelled. Robot arm 24 is an arm that can be positioned freely in space, and is, for example, a robot arm that can rotate around four or six axes. Torch member 26 is formed of a metal material that can propagate processing waves generated when workpiece 10 is processed, such as elastic waves (acoustic emission: AE waves) generated in workpiece 10 during welding. A welding electrode (metal wire) is inserted into torch member 26 and protrudes from the tip of torch member 26.

[0010] Second welding machine 20B is configured similarly to first welding machine 20A, namely, second welding machine 20B has base 22, robot arm 24 rotatably mounted on base 22, torch member 26 (sometimes referred to as second torch member) attached to the tip of robot arm 24, and power supply unit 28 that applies a drive voltage between a welding electrode (described later) and workpiece 10. First welding machine 20A and second welding machine 20B are arranged on either side of object to be welded 10 with object to be welded 10 sandwiched therebetween.

[0011] The monitoring device 30 has a first AE sensor S1 attached to the torch member 26 of the first welding machine 20A, a second AE sensor S2 attached to the torch member 26 of the second welding machine 20B, a first processing circuit that processes the detection signal of the first AE sensor S1, and a second processing circuit that processes the detection signal of the second AE sensor S2. First AE sensor S1 is installed at the base end of torch member 26 of first welding machine 20A and detects AE waves propagating through torch member 26. Second AE sensor S2 is installed at the base end of torch member 26 of second welding machine 20B and detects AE waves propagating through torch member 26 of second welding machine 20B. In this embodiment, the first processing circuit and the second processing circuit are configured within controller 60.

[0012] The configuration of the torch member and the configuration of the controller will be described in detail below. FIG. 2 is a diagram showing the cross-sectional structure of the torch member and the configuration of the controller. As shown in the figure, the torch member 26 of the first welding machine 20A is formed in the shape of an elongated rod from a metal material capable of propagating AE waves, and has a base end (joint block 31) connected to the robot arm 24 and a tip end adjacent to and facing the workpieces 10. In one example, the torch member 26 has a torch body clamp 32 connected to the robot arm 24 or constituting a part of the robot arm 24, a sleeve-shaped torch body 34 having one end connected to the torch body clamp 32, a cylindrical tip body 35 having one end connected to the other end of the torch body 34, an elongated tip 36 having an inner hole and one end connected to the other end of the tip body 35, a cylindrical nozzle 37 having one end connected to the other end of the tip body 35, and a joint block 31 connected to one end of the torch body 34 and the robot arm 24. In this embodiment, the joint block 31 is attached to the torch body clamp 32, but it may also be attached to the torch body .

[0013] The torch body clamp 32, torch body 34, tip body 35, tip 36, nozzle 37, and joint block 31 that make up the torch member 26 are made of a metal material capable of propagating AE waves, such as, but not limited to, steel, copper, or brass. Furthermore, the torch body clamp 32, torch body 34, tip body 35, tip 36, nozzle 37, and joint block 31 are in close contact with each other to form a continuous structure. While the torch body 34 in this embodiment is straight, it may also be curved.

[0014] First welding machine 20A has welding electrode EL1 as a first electrode and second electrode EL2 that passes current through workpiece 10. Welding electrode EL1 is a long, thin metal wire that is inserted from robot arm 24 into a passage (inner hole) in torch member 26 and extends to the tip of torch member 26. Welding electrode EL1 is held by torch member 26 in a state where it protrudes slightly from the tip of tip 23. Welding electrode EL1 is made of a metal material such as steel, stainless steel, or aluminum. During welding, a drive voltage is applied to welding electrode EL1 and second electrode EL2 from power supply 28 of first welding machine 20A. Welding electrode EL1 is continuously powered by contact with tip 36, and an arc is generated between workpiece 10 and welding electrode EL1. This arc welds first weld WA.

[0015] FIG. 3 is a perspective view showing a joint block portion of the torch member and the first AE sensor. 3, the joint block 31 is formed in an annular shape and has a flat installation surface 50 on part of its outer periphery. In one example, a protrusion 52 is formed integrally with the outer periphery of the joint block 31, and the end face of the protrusion 52 forms the flat installation surface 50. Note that a configuration may also be adopted in which a part of the outer periphery of the joint block is machined into the flat installation surface 50 without providing a protrusion.

[0016] The first AE sensor S1 is installed on the installation surface 50 of the joint block 31. More specifically, the first AE sensor S1 has a flat receiving surface, and is attached to the joint block 31 with this receiving surface in close contact with the installation surface 50. The first AE sensor S1 is connected via wiring to a first processing circuit, which will be described later. Note that the first AE sensor S1 is not limited to the rectangular pillar shape shown in the figure, and sensors of any shape can be used.

[0017] As shown in FIG. 2, the second welding machine 20B has a similar configuration to the first welding machine 20A. The same reference numerals are used for the same components. The torch member 26 of the second welding machine 20B, like the torch member 26 of the first welding machine 20A, is composed of a torch body clamp 32, a torch body 34, a tip body 35, a tip 36, a nozzle 37, and a joint block 31, all of which are made of a metal material capable of propagating AE waves, such as steel, copper, or brass. The torch body clamp 32, the torch body 34, the tip body 35, the tip 36, the nozzle 37, and the joint block 31 are closely fitted together to form a continuous structure. The joint block 31 has a flat mounting surface 50 on a portion of its outer periphery. The second AE sensor S2 is attached to the joint block 31 with its receiving surface in close contact with the mounting surface 50. The second welding machine 20B has a welding electrode (metal wire) EL1 inserted into a torch member 26 and a second electrode EL2 that applies current to the workpiece 10.

[0018] 2, the controller 60 includes an MPU (microprocessor) 62 that functions as a main control unit, and a memory 64 that stores various data such as determination results and reference data. In this embodiment, the controller 60 includes a first processing circuit 40A and a second processing circuit 40B that constitute part of the monitoring device 30. The MPU 62 is connected to the first welding machine 20A, the second welding machine 20B, the first processing circuit 40A, and the second processing circuit 40B, and controls their operations. The MPU 62 also stores the determination results obtained by the first processing circuit 40A and the second processing circuit 40B in the memory 64.

[0019] First welding machine 20A configured as described above applies a voltage between workpiece 10 and welding electrode EL1 to cause dielectric breakdown and generate an arc at first welded portion WA of workpiece 10. Second welding machine 20B applies a voltage between workpiece 10 and welding electrode EL1 to cause dielectric breakdown and generate an arc at second welded portion WB. In this embodiment, the time when an arc is generated at first welded portion WA and the time when an arc is generated at second welded portion WB are the same, but this embodiment is also effective when the time when an arc is generated at first welded portion WA and the time when an arc is generated at second welded portion WB are not the same. First welded portion WA and second welded portion WB are spatially separated. In this embodiment, the distance between first welded portion WA and second welded portion WB is approximately 30 cm, but the distance may be longer.

[0020] The monitoring device 30 of this embodiment is a system that detects the welding condition of the first welded portion WA and the second welded portion WB, which are the objects to be welded, by detecting unsteady elastic waves (AE waves) generated at the tip of the welding electrode during welding of the workpiece 10. 2, monitoring device 30 includes a first AE sensor S1 attached to torch member 26 of first welding machine 20A, a second AE sensor S2 attached to torch member 26 of second welding machine 20B, a first processing circuit 40A that processes a detection signal from first AE sensor S1, and a second processing circuit 40B that processes a detection signal from second AE sensor S2. In this embodiment, first processing circuit 40A and second processing circuit 40B are configured within controller 60. Joint block 31 on which AE sensors S1 and S2 are installed may be an element that configures part of monitoring device 30.

[0021] The first AE sensor S1 receives the elastic waves generated from the first welded zone WA via the torch member 26 and converts the elastic waves into an electrical signal. Similarly, the second AE sensor S2 receives the elastic waves generated from the second welded zone WB via the torch member 26 and converts the elastic waves into an electrical signal.

[0022] The first AE sensor S1 and the second AE sensor S2 each have a piezoelectric element as a conversion element. The piezoelectric element is made of PZT (lead zirconate titanate), LiNbO3 (lithium niobate single crystal), GaPO4 (gallium phosphate), AlN (aluminum nitride), La3Ga5SiO14 (langasite), Ga2Al2SiO7, etc. Piezoelectric elements made of LiNbO3, AlN, Ga2Al2, SiO7, etc. are particularly suitable for use in harsh environments with high temperatures and high radiation levels. The conversion elements of the first AE sensor S1 and the second AE sensor S2 may be electromagnetic acoustic transducers (EMATs) that convert acoustic energy into an electric signal (electrical vibration) by the interaction of the electromagnetic induction effect and the magnetic field. The first AE sensor S1 and the second AE sensor S2 are preferably selected to have highly sensitive frequency characteristics in the waveform spectrum of the elastic waves generated by the welding phenomenon. In this embodiment, sensors with highly sensitive frequency characteristics in the 100 kHz to 200 kHz band are selected, but the range is not limited to this frequency band.

[0023] The first processing circuit 40A of the monitoring device 30 includes a first detection unit 41a that detects the signal from the first AE sensor S1, a first recording unit 42a that records the detection signal, and a first determination unit 44a that determines the welding condition of the first welded zone WA based on the detection signal. The second processing circuit 40B includes a second detection unit 41b that detects the signal from the second AE sensor S2, a second recording unit 42b that records the detection signal, and a second determination unit 44b that determines the welding condition of the second welded zone WB based on the detection signal.

[0024] The first detection unit 41a is electrically connected to the first AE sensor S1 and amplifies and filters the electrical signal sent from the first AE sensor S1. Similarly, the second detection unit 41b is electrically connected to the second AE sensor S2 and amplifies and filters the electrical signal sent from the second AE sensor S2. Specifically, the first detection unit 41a and the second detection unit 41b include circuits that electrically amplify weak electrical signals sent from the piezoelectric elements of the first AE sensor S1 and the second AE sensor S2 and perform frequency filtering as necessary. These circuits can be configured with analog or digital circuits. These circuits may also include a programmable logic device (hereinafter referred to as a PLD). For example, a programmable gate array, known as an FPGA (field-programmable gate array), can be used as the PLD. It is desirable to electrically amplify the weak electrical signals by a factor of 10 or more.

[0025] The frequency of the elastic waves generated from the weld is generally several kHz to several MHz. Therefore, it is preferable that the amplification band of the first detection unit 41a and the second detection unit 41b be a wide band of approximately several kHz to several tens of MHz. The frequency filtering process for amplifying this band can be achieved by using a high-pass filter, a low-pass filter, and a band-pass filter.

[0026] The first recording unit 42a records the electrical signal of the first AE sensor S1 sent from the first detection unit 41a, and the second recording unit 42b records the electrical signal of the second AE sensor S2 sent from the second detection unit 41b. In this embodiment, each of the first recording unit 42a and the second recording unit 42b has a processor (not shown) capable of performing various calculations and a memory (not shown) capable of storing various constants. Each of the first recording unit 42a and the second recording unit 42b can be realized by a general computer. Note that the first recording unit 42a and the second recording unit 42b may be configured using multiple electrical circuits (processing circuits) or multiple computers for each of the various functions.

[0027] The first determination unit 44a is electrically connected to the first recording unit 42a and determines the welding condition of the first welded portion WA based on the recording of the detection signal of the first AE sensor S1. Specifically, the first determination unit 44a determines the quality of the welding condition of the first welded portion WA by comparing the detection signal of the first AE sensor S1 with pre-prepared reference data (recorded signals of good welds). The second determination unit 44b is electrically connected to the second recording unit 42b and determines the welding condition of the second welded portion WB based on the recording of the detection signal of the second AE sensor S2. Specifically, the second determination unit 44b determines the quality of the welding condition of the first welded portion WA by comparing the detection signal of the second AE sensor S1 with reference data (recorded signals of a good welded portion).

[0028] Next, the operation of the welding device 100 and monitoring device 30 configured as above will be described. During welding, first welding machine 20A applies a drive voltage to welding electrode EL1 and second electrode EL2 from power supply 28 under the control of controller 60. Welding electrode EL1 is continuously powered by contact with tip 36, and applying a voltage between workpiece 10 and welding electrode EL1 causes dielectric breakdown and generates an arc at first weld zone WA. The generated arc welds first weld zone WA. With power supplied to welding electrode EL1, robot arm 24 is driven to move the tip of torch member 26 along first weld zone WA, thereby continuously welding first weld zone WA.

[0029] Similarly, under the control of controller 60, second welding machine 20B applies a drive voltage from power supply 28 to welding electrode EL1 and second electrode EL2. Welding electrode EL1 is continuously powered by contact with tip 36, and applying a voltage between workpiece 10 and welding electrode EL1 causes dielectric breakdown and generates an arc at second weld zone WB. The generated arc welds second weld zone WB. With power supplied to welding electrode EL1, robot arm 24 is driven to move the tip of torch member 26 along second weld zone WB, thereby continuously welding second weld zone WB. In this embodiment, the welding timing of the first welded portion WA and the welding timing of the second welded portion WB are approximately the same, but this is not limited to this, and this embodiment is also effective when the welding timings of both are not simultaneous. The first welded portion WA and the second welded portion WB are spatially separated. In this embodiment, the distance between the first welded portion WA and the second welded portion WB is approximately 30 cm, but the distance may be greater.

[0030] FIG. 4 is a flowchart showing an example of the operation of the monitoring device 30. As shown in the figure, in welding, power is supplied from power supply 28 to welding electrode EL1 (ST1), and an arc is generated at first welded portion WA and second welded portion WB. When an arc is generated at the weld, a droplet transfer phenomenon occurs from welding electrode ELE1 at the weld. As the droplet transfer occurs, unsteady elastic waves (AE waves) are generated at the tip of welding electrode EL1. At the first welded portion WA, unsteady elastic waves generated at welding electrode EL1 propagate through torch member 26 of first welding machine 20A, i.e., through tip 36, tip body 35, torch body 34, and joint block 31, and reach first AE sensor S1 installed on installation surface 50 of joint block 31. Similarly, at the second welded portion, unsteady elastic waves generated at welding electrode EL1 propagate through torch member 26 of second welding machine 20B, i.e., through tip 36, tip body 35, torch body 34, and joint block 31, and reach second AE sensor S2 installed on installation surface 50 of joint block 31. A conversion element such as a piezoelectric element provided in each of the first AE sensor S1 and the second AE sensor S2 receives the acoustic waves that have reached it and converts the acoustic energy into an electric signal, for example, a voltage.

[0031] The elastic waves that reach first AE sensor S1 reflect the droplet transfer phenomenon at first weld WA and do not include elastic waves caused by cracks occurring in workpiece 10 or elastic waves caused by droplet transfer phenomenon at second weld WB. Elastic waves caused by cracks occurring in workpiece 10 and elastic waves caused by droplet transfer phenomenon at second weld WB propagate through workpiece 10, but the elastic waves propagating through workpiece 10 do not propagate to welding electrode EL1 of first weld WA (first welder 20A). This is because the gap between workpiece 10 and welding electrode EL1 is filled with gas.

[0032] Similarly, the elastic waves reaching the second AE sensor S2 reflect the droplet transfer phenomenon at the second welded portion WB, and do not include elastic waves caused by cracks occurring in the workpiece 10 or elastic waves caused by the droplet transfer phenomenon at the first welded portion WA. As a result, the first AE sensor S1 generates an electrical signal representing an elastic wave that reflects only the welding condition of the first welded portion WA. The second AE sensor S2 generates an electrical signal representing an elastic wave that reflects only the welding condition of the second welded portion WB. The electrical signal generated by the first AE sensor S1 is sent to the first detection unit 41a of the first processing circuit 40A. The electrical signal generated by the second AE sensor S2 is sent to the second detection unit 41b of the second processing circuit 40B.

[0033] The first detector 41a detects elastic waves by amplifying and filtering the electrical signal sent from the first AE sensor S1 (ST2). Similarly, the second detector 41b detects elastic waves by amplifying and filtering the electrical signal sent from the second AE sensor S2 (ST2). The first recording unit 42a records the feature amount of the waveform of the electrical signal of the first AE sensor S1 sent from the first detection unit 41a (ST3). The second recording unit 42b records the feature amount of the waveform of the electrical signal of the second AE sensor S2 sent from the second detection unit 41b (ST3).

[0034] The first determination unit 44a determines whether the welding state of the first welded portion WA is good or bad by comparing the feature amount of the waveform recorded in the first recording unit 42a with pre-prepared reference data (recorded signals of good welds) (ST4). The determination result is recorded in the memory 64 of the controller 60 (ST5). Similarly, the second determination unit 44b determines whether the welding state of the second welded portion WB is good or bad by comparing the feature amount of the waveform recorded in the second recording unit 42b with pre-prepared reference data (recorded signals of good welded parts) (ST4). The determination result is recorded in the memory 64 of the controller 60 (ST5).

[0035] 5 is a diagram showing an example of the welding timing of the welding device 100 according to this embodiment and the signal intensity of the elastic wave detected by the monitoring device 30. In FIG. 5, (a) shows the welding timing of the first welded portion WA (solid line) and the welding timing of the second welded portion WB (dashed line). (b) shows an example of the waveform of the elastic wave transmitted from the first AE sensor S1, detected by the first detector 41a, and recorded by the first recorder 42a, showing the signal intensity relative to the measurement time t. (c) shows an example of the waveform of the elastic wave transmitted from the second AE sensor S2, detected by the second detector 41b, and recorded by the second recorder 42b, showing the signal intensity relative to the measurement time t.

[0036] As shown in Figure 5, the waveform of the elastic wave detected by the first AE sensor S1 is not affected by the elastic wave generated by welding the second welded portion WB, and the signal strength is confirmed in accordance with the welding timing of the first welded portion WA. This shows that the first AE sensor S1 generates an electrical signal representing an elastic wave that reflects only the welding condition of the first welded portion WA. Similarly, the waveform of the elastic wave detected by the second AE sensor S2 is not affected by the elastic wave generated by the welding of the first welded portion WA, and the signal strength is confirmed in accordance with the welding timing of the second welded portion WB. This indicates that the second AE sensor S2 generates an electrical signal representing an elastic wave that reflects only the welding condition of the second welded portion WB.

[0037] With the welding apparatus 100 and monitoring device 30 according to this embodiment configured as described above, even when two welders 20A, 20B are simultaneously welding the first welded portion WA and the second welded portion WB of the same workpiece 10, the first AE sensor S1 can generate an electrical signal representing an elastic wave that reflects only the welding state of the first welded portion WA, and the second AE sensor S2 can generate an electrical signal representing an elastic wave that reflects only the welding state of the second welded portion WB. This makes it possible to accurately monitor (determine) the welding state of the first welded portion WA and the welding state of the second welded portion WB separately, even when the first welded portion WA and the second welded portion WB of the workpiece 10 are simultaneously welded.

[0038] Furthermore, according to this embodiment, the torch member 26 has a flat installation surface 50, and each of the AE sensors S1, S2 is installed on the torch member 26 with its receiving surface in close contact with the installation surface 50. This allows each of the AE sensors S1, S2 to easily detect elastic waves propagating through the torch member 26 with high accuracy.

[0039] Furthermore, the first AE sensor S1 and the second AE sensor S2 are provided at a position where they can detect elastic waves of sufficient signal strength while maintaining a sufficient distance from the first welded zone WA and the second welded zone WB and are not affected by spatter or processing heat generated at the first welded zone WA and the second welded zone WB, in this embodiment, at the base end (joint block 31) of the torch member 26. Therefore, even when the first AE sensor S1 and the second AE sensor S2 are provided on the torch member 26 made of a metallic material, they can maintain high detection performance and reliability. As described above, according to this embodiment, it is possible to provide a welding apparatus and a welding monitoring apparatus that can accurately monitor the welding state of each weld, even when multiple locations on the same welding object are welded simultaneously.

[0040] Although the present embodiment has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims.

[0041] For example, in the above-described embodiment, the number of welding machines is not limited to two, but may be three or more. By providing an AE sensor on the torch member of each welding machine, the same effects as those of the above-described embodiment can be obtained. Various welding machines can be used, including gas-shielded arc welding machines for MAG welding and MIG welding. The configuration of the torch member is not limited to the configuration of the above-described embodiment, and can be modified in various ways as needed or depending on the model of the welding machine. The installation surface for installing the AE sensor is not limited to the base end (joint block) of the torch member, but may be provided on another part of the torch member, for example, on the outer periphery of the torch body. In other words, the installation position of the AE sensor may be any position on the torch member that is not affected by spatter or processing heat generated at the welded portion, is distant from the welded portion, and can detect elastic waves with sufficient signal strength. [Explanation of symbols]

[0042] 10...workpiece to be welded, 20A...first welding machine, 20B...second welding machine, 22...base, 24...Robot arm, 26...Torch member, 28...Power supply unit, 30...Monitoring device, 31...Joint block (base end), 34...Torch body, 35...Tip body, 36... tip, 37... nozzle, 40A... first processing circuit, 40B... second processing circuit, 50...Installation surface, 60...Controller, S1...First AE sensor, S2...Second AE sensor, EL1...Welding electrode

Claims

1. a first welding machine for welding a first welded portion of the workpiece, the first welding machine including: an arm; a first torch member formed of a metal material having a base end connected to the arm, a tip end facing the workpiece, and a flat installation surface; a welding electrode inserted into the first torch member and protruding from the tip end; and a power supply unit for applying a voltage between the welding electrode and the workpiece; a second welding machine including: an arm; a second torch member made of a metal material having a base end connected to the arm, a tip end facing the workpieces, and a flat installation surface; a welding electrode inserted into the second torch member and protruding from the tip end; and a power supply unit applying a voltage between the welding electrode and the workpieces, the second welding machine welding a second weld portion different from the first weld portion of the workpieces; a monitoring device comprising: a first sensor installed on a mounting surface of the first torch member and detecting elastic waves transmitted to the first torch member; a second sensor installed on a mounting surface of the second torch member and detecting elastic waves transmitted to the second torch member; a first processing circuit that determines the welding condition of the first welded portion based on a detection signal sent from the first sensor; and a second processing circuit that determines the welding condition of the second welded portion based on a detection signal sent from the second sensor; A welding device comprising:

2. Each of the first torch member and the second torch member includes an annular joint block constituting the base end, a tip and a tip body constituting the front end, and a torch body positioned between the joint block and the tip body, The welding device of claim 1 , wherein the joint block includes the mounting surface.

3. 3. The welding device according to claim 2, wherein the joint block has a convex portion formed on an outer periphery thereof, and the flat installation surface is provided on the convex portion.

4. the first processing circuit includes a first detection unit that detects a detection signal of the first sensor, a first recording unit that records a feature amount of a waveform of the detection signal, and a first determination unit that determines whether the welding state of the first welded portion is good or bad based on the recorded feature amount; 2. The welding device according to claim 1, wherein the second processing circuit includes a second detection unit that detects a detection signal from the second sensor, a second recording unit that records a feature of a waveform of the detection signal, and a second determination unit that determines whether the welding state of the second welded portion is good or bad based on the recorded feature.

5. a welding state of a first weld of the workpieces welded by a first welding machine including: a first torch member formed of a metal material and having a base end and a tip end facing the workpieces; a welding electrode inserted into the first torch member and protruding from the tip end; and a power supply unit that applies a voltage between the welding electrode and the workpieces; A monitoring device for detecting a welding state of a second weld of a workpiece to be welded by a second welding machine including: a second torch member having a base end and a tip end facing the workpiece, the second torch member being made of a metal material; a welding electrode inserted into the second torch member and protruding from the tip end; and a power supply unit applying a voltage between the welding electrode and the workpiece, a first AE sensor installed on the first torch member and configured to detect elastic waves transmitted to the first torch member; a second AE sensor installed on the second torch member to detect elastic waves transmitted to the second torch member; a first processing circuit that determines a welding state of the first welded portion based on a detection signal sent from the first AE sensor; a second processing circuit that determines a welding state of the second welded portion based on a detection signal sent from the second AE sensor; A monitoring device comprising:

6. 6. The monitoring device according to claim 5, wherein the first torch member has a flat installation surface formed at the base end, and the first AE sensor is installed in close contact with the installation surface.

7. 6. The monitoring device according to claim 5, wherein the second torch member has a flat installation surface formed at the base end, and the second AE sensor is installed in close contact with the installation surface.

8. the first processing circuit includes a first detection unit that detects a detection signal from the first AE sensor, a first recording unit that records a feature amount of a waveform of the detection signal, and a first determination unit that determines whether a welding state of the first welded portion is good or bad based on the recorded feature amount; 6. The monitoring device according to claim 5, wherein the second processing circuit includes a second detection unit that detects a detection signal from the second AE sensor, a second recording unit that records a feature amount of a waveform of the detection signal, and a second determination unit that determines whether the welding state of the second welded portion is good or bad based on the recorded feature amount.

Images