Welding equipment

Abstract

To enable a torch portion to easily follow a groove.SOLUTION: Welding equipment 1 comprises: a torch portion 3 that performs welding of a groove 93 formed in such a way as to extend in a predetermined longitudinal direction, at a butted portion between materials 91 to be welded; a support portion 4 that supports the torch portion 3 movably in a width direction in which the materials 91 to be welded are lined up; a moving mechanism 2 that moves the support portion 4 in a welding direction along the longitudinal direction together with the torch portion 3; and a copying mechanism 5 which is fixed with respect to the torch portion 3 and arranges a reference position of the torch portion 3 at a predetermined position of a groove 93 in the width direction. The copying mechanism 5 comprises: a support shaft 511 extending along a depth direction of the groove 93; a pair of contacts mounted on an end portion at the groove 93 side of the support shaft 511 and arranged at both sides across the support shaft 511 when viewed along the support shaft 511; and a rotating mechanism 512 that causes the pair of contacts to come in contact with both side surfaces of the groove 93 respectively, by rotating the support shaft 511 while the end portion of the support shaft 511 is inserted into the groove 93.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a welding apparatus.

Background Art

[0002] Conventionally, welding apparatuses that perform welding on a groove formed in a butted portion between materials to be welded have been used. A welding apparatus is provided with a configuration for causing a torch portion to follow the groove. For example, in the apparatus of Patent Document 1, contacts are provided at positions the same distance from the rotation shaft at both end portions of a rotating arm fixed to the lower end of the rotation shaft. When the rotation shaft rotates, first, the contact end member of one contact abuts against one side surface of the groove, and then the other contact abuts against the other side surface. Based on the rotation angle of the rotating arm when each contact comes into contact with the side surface of the groove, position information of the groove and the like are obtained by a calculation unit. In addition, in each contact of Patent Document 1, a coil spring is provided between the contact end member and the rotating arm. When the contact end member of one contact abuts against the side surface of the groove, the movement of the contact end member is stopped, but the bending of the coil spring exerts no stopping constraint force on the rotating arm.

[0003] Patent Document 2 discloses a method for detecting a groove width. In this method, a roller having a tapered outer peripheral portion with a constant angle is arranged so as to enter the groove in front of the welding arc. Further, distance detection means for measuring the distance to the plate surface of the member to be welded are fixed to both left and right sides of the roller. Then, the variation amount of the groove width is detected from the sum of the displacement amounts of the left and right distances.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of Invention

Problems to be Solved by the Invention

[0005] However, the devices described in Patent Documents 1 and 2 require complex calculations to acquire information such as the position of the groove and the amount of variation in the groove width. Therefore, there is a need for a novel method that allows the torch to easily conform to the groove.

[0006] This invention has been made in view of the above problems, and aims to allow the torch to easily conform to the groove. [Means for solving the problem]

[0007] One aspect of the present invention is a welding apparatus comprising: a torch section for welding a groove formed in a predetermined longitudinal direction at a butt joint between materials to be welded; a support section that supports the torch section in a movable state in the width direction in which the materials to be welded are lined up; a movement mechanism that moves the support section together with the torch section relative to the materials to be welded in the welding direction along the longitudinal direction; and a tracing mechanism fixed to the torch section that positions a reference position of the torch section at a predetermined position of the groove in the width direction, wherein the tracing mechanism comprises: a support shaft extending along the depth direction of the groove; a pair of contacts attached to the end of the support shaft on the groove side and arranged on both sides of the support shaft when viewed along the support shaft; and a rotation mechanism that rotates the support shaft with the end of the support shaft inserted into the groove, thereby bringing the pair of contacts into contact with both sides of the groove, respectively.

[0008] Aspect 2 of the present invention is a welding apparatus according to aspect 1, wherein the predetermined position of the groove in the width direction is the center of the groove, and the pair of contacts are separated by the same distance from the support shaft.

[0009] A third aspect of the present invention is a welding apparatus according to aspect 1 (or aspect 1 or 2), wherein each of the pair of contacts is a roller rotatable about a central axis along the support shaft.

[0010] Aspect 4 of the present invention is a welding apparatus according to Aspect 1 (which may be any one of Aspects 1 to 3), wherein the torch section comprises a plurality of welding torches arranged in an arrangement direction along the welding direction, the support section is capable of changing the inclination angle of the arrangement direction with respect to the welding direction in a plane perpendicular to the depth direction, the tracing mechanism comprises a position adjustment section having the support shaft, the pair of contacts and the rotation mechanism, and another position adjustment section having a structure similar to that of the position adjustment section, and the plurality of welding torches are arranged between the position adjustment section and the other position adjustment section with respect to the welding direction.

[0011] Aspect 5 of the present invention is a welding apparatus according to aspect 4, wherein the support portion includes a connecting portion that connects the movable body of the moving mechanism and the torch portion, the connecting portion is rotatable with respect to the movable body about a first rotation axis along the depth direction, the torch portion is rotatable with respect to the connecting portion about a second rotation axis along the depth direction, the rotation of the connecting portion about the first rotation axis and the rotation of the torch portion about the second rotation axis allow the torch portion to move in the width direction, and the inclination angle in the arrangement direction can be changed.

[0012] Aspect 6 of the present invention is a welding apparatus according to any one of aspects 1 to 5, further comprising: a groove width acquisition unit that acquires the width of the groove based on the rotation angle of the support shaft when the pair of contacts are in contact with both sides of the groove; and a control unit that determines welding conditions based on the output of the groove width acquisition unit.

[0013] Aspect 7 of the present invention is a welding apparatus according to aspect 6, wherein the support shaft of the tracing mechanism is provided with a detection unit that protrudes from the support shaft, the position of the detection unit in one direction perpendicular to the support shaft changes according to the rotation angle of the support shaft, and the groove width acquisition unit acquires the groove width by measuring the position of the detection unit in one direction.

[0014] Aspect 8 of the present invention is the welding apparatus according to any one of Aspects 1 to 5 (which may be any one of Aspects 1 to 7), wherein in the torch section, a spray nozzle for spraying flux and a welding torch for performing welding are provided along the welding direction, during welding of the groove, the spray port of the spray nozzle and the end portion of the welding torch are disposed inside the groove, the spray nozzle and the welding torch sequentially pass through each position of the groove in the welding direction, the width of the groove is not more than twice the diameter of the end portion of the welding torch, and the height from the bottom surface of the groove to the spray port of the spray nozzle is not more than the height from the bottom surface of the groove to the tip of the end portion of the welding torch. Effects of the Invention

[0015] According to the present invention, the torch section can be easily made to follow the groove. Brief Description of the Drawings

[0016] [Figure 1] It is a front view showing the welding apparatus. [Figure 2] It is a right side view showing the welding apparatus. [Figure 3] It is a view showing the vicinity of the end portion of the welding torch and the spray port of the spray nozzle. [Figure 4] It is a plan view showing the support section. [Figure 5] It is a view showing the configuration of the groove width acquisition section. [Figure 6] It is a view for explaining the operation of the copying mechanism. [Figure 7] It is a view for explaining the operation of the groove width acquisition section. [Figure 8] It is a view showing another example of the groove width acquisition section. Modes for Carrying Out the Invention

[0017] FIG. 1 is a front view showing a welding device 1 according to an embodiment of the present invention. FIG. 2 is a right side view showing the welding device 1. The welding device 1 is a device that joins a plurality of workpieces 91 by arc welding, and in the present embodiment, submerged arc welding is performed. Welding other than submerged arc welding may be performed in the welding device 1. In FIG. 1 and FIG. 2, three mutually orthogonal directions are indicated by arrows as an X direction, a Y direction, and a Z direction (the same applies to other drawings). The X direction and the Y direction are horizontal directions, and the Z direction is the vertical direction. The X direction and the Y direction may be inclined with respect to the horizontal direction, and the Z direction may be inclined with respect to the vertical direction.

[0018] The welding device 1 performs welding on a groove 93 formed at the butt portion between the workpieces 91. In the example shown in FIG. 1 and FIG. 2, the workpieces 91 are arranged in the Y direction, and the groove 93 which is a recess in the Z direction extends in the longitudinal direction along the X direction. In the welding device 1, a torch unit 3 to be described later moves in the X direction to form a weld bead extending in the longitudinal direction of the groove 93 inside the groove 93. Hereinafter, the X direction is also referred to as "welding direction", and the Y direction in which the workpieces 91 are arranged is also referred to as "width direction".

[0019] In the present embodiment, the width of the groove 93 in the width direction is relatively narrow (for example, 16 to 20 mm), and the weld bead spreads over substantially the entire width of the groove 93. The groove angle is approximately 0°, and the welding device 1 repeats the formation of the weld bead N times (N is an integer of 2 or more), whereby N layers of weld beads are stacked in the depth direction of the groove 93 (that is, the Z direction). In this way, the weld beads are stacked by one pass per layer from the first layer to the final layer. The depth of the groove 93 may be determined arbitrarily, and is, for example, 200 mm. In the example shown in FIG. 1 and FIG. 2, the depth direction of the groove 93 is parallel to the vertical direction. The depth direction of the groove 93 may be inclined with respect to the vertical direction. In the welding device 1, single-layer welding may be performed, and as will be described later, one layer may be formed by a plurality of passes.

[0020] The welding apparatus 1 shown in Figure 1 comprises a moving mechanism 2, a torch section 3, a support section 4, a tracing mechanism 5, a groove depth acquisition section 6, a groove width acquisition section 7, and a control unit 10. The control unit 10 includes an automatic control panel and a computer, etc. The control unit 10 is electrically connected to each component of the welding apparatus 1 and is responsible for the overall control of the welding apparatus 1. The torch section 3 comprises a plurality of welding torches 31a, 31b, a plurality of spray nozzles 32a, 32b, 32c, a plurality of wire feeders 33a, 33b, a flux supply section (not shown), a holding block 36, and a base section 37.

[0021] Multiple welding torches 31a, 31b and multiple spray nozzles 32a to 32c each extend along the vertical direction (Z direction) and are fixed to a holding block 36 that extends along the welding direction (X direction). In the example in Figure 1, two welding torches 31a, 31b and three spray nozzles 32a to 32c are provided, and the spray nozzles 32a, welding torch 31a, spray nozzle 32b, welding torch 31b, and spray nozzle 32c are arranged in order from the (+X) side to the (-X) side. When viewed along the vertical direction, the spray nozzles 32a, welding torch 31a, spray nozzle 32b, welding torch 31b, and spray nozzle 32c are arranged on a straight line, and this straight line will be referred to below as the "reference line of the torch section 3" (see the dashed line K1 in Figure 4 described later). Furthermore, the arrangement direction of the welding torches 31a, 31b and spray nozzles 32a to 32c will hereafter be referred to as the "torch arrangement direction." As will be described later, the inclination angle of the torch arrangement direction with respect to the welding direction can be changed in a plane perpendicular to the vertical direction. In the description of the structure of the welding apparatus 1, it will be assumed that the torch arrangement direction is parallel to the welding direction.

[0022] During the welding process, the torch section 3 moves from the (-X) side to the (+X) side, so that the spray nozzle 32a, welding torch 31a, spray nozzle 32b, welding torch 31b, and spray nozzle 32c pass through each position of the groove 93 in the welding direction in order. In the following description, welding torch 31a and welding torch 31b will also be referred to as "leading welding torch 31a" and "following welding torch 31b," respectively. Also, spray nozzles 32a, spray nozzle 32b, and spray nozzle 32c will be referred to as "leading spray nozzle 32a," "intermediate spray nozzle 32b," and "following spray nozzle 32c," respectively.

[0023] Figure 3 shows the ends 311 of the welding torches 31a and 31b, and the vicinity of the spray nozzles 320 of the spray nozzles 32a to 32c. As will be described later, when welding is performed on the groove 93, the ends 311 of the welding torches 31a and 31b (the (-Z) side ends) and the spray nozzles 320 of the spray nozzles 32a to 32c are positioned within the groove 93. Figure 3 shows the welding torches 31a and 31b and the spray nozzles 32a to 32c positioned within the groove 93, and the cross-section of the workpiece 91 and the spray nozzles 32a to 32c is shown approximately in the center of the width of the groove 93 (a cross-section perpendicular to the width direction).

[0024] The end 311 of the leading welding torch 31a and the end 311 of the trailing welding torch 31b are positioned close to each other. In the example in Figure 3, the leading welding torch 31a is approximately parallel in the vertical direction, and the trailing welding torch 31b is inclined to be located on the (-X) side as it moves from the bottom to the top (from the (-Z) side to the (+Z) side). The welding torches 31a and 31b are cylindrical, and the cross-section perpendicular to the longitudinal direction of the welding torches 31a and 31b is approximately annular. For example, the outer diameter of the welding torches 31a and 31b is 10 mm, and the inner diameter is 4 mm. Of course, the size of the welding torches 31a and 31b may be changed as appropriate. The welding torches 31a and 31b are made of a metal such as copper and have sufficient heat resistance. Inside the welding torches 31a and 31b, the filler material, wire 310, is fed from the wire feeding devices 33a and 33b (see Figure 1). An insulating material may be wrapped around the outer surface of the wire 310 to ensure insulation between the wire 310 and the side surface 931 of the groove 93. Each welding torch 31a, 31b and the workpiece 91 are electrically connected to a welding power source (not shown).

[0025] When the torch arrangement direction is parallel to the welding direction, the cross-sectional shape of the spray nozzles 32a to 32c perpendicular to the vertical direction is a roughly rectangular shape that is elongated in the welding direction, and the width in the width direction is the same as, or slightly smaller than, the diameter of the end 311 of the welding torches 31a and 31b. The leading spray nozzle 32a is roughly parallel to the vertical direction and is positioned close to the (+X) side of the leading welding torch 31a. The intermediate spray nozzle 32b has a side surface on the (+X) side that is close to and along the leading welding torch 31a and a side surface on the (-X) side that is close to and along the trailing welding torch 31b. The trailing spray nozzle 32c is positioned close to the (-X) side of the trailing welding torch 31b and is roughly parallel to the trailing welding torch 31b.

[0026] Flux is supplied from the flux supply unit to the inside of the spray nozzles 32a to 32c. As a result, flux is sprayed into the groove 93 from the spray openings 320 of each spray nozzle 32a to 32c. In the vertical direction, the height from the bottom surface 932 of the groove 93 to the spray openings 320 of each spray nozzle 32a to 32c is the same as, or lower than, the height from the bottom surface 932 to the tip of the end 311 of each welding torch 31a, 31b (i.e., the tip of the part surrounding the wire 310).

[0027] In submerged arc welding, welding is performed by generating an arc between the workpiece 91 and the wire 310 with the tip of the wire 310 covered in flux. In welding apparatus 1, which is equipped with an intermediate spray nozzle 32b and a trailing spray nozzle 32c in addition to the leading spray nozzle 32a, an appropriate amount of flux can be supplied into the groove 93, and the occurrence of an open arc, in which the arc leaks out of the flux, can be suppressed.

[0028] In this embodiment, the width of the groove 93 is extremely narrow, less than or equal to twice the diameter of the ends 311 of the welding torches 31a and 31b. Because the width of the groove 93 is greater than the diameter, it is possible to position the ends 311 of the welding torches 31a and 31b within the groove 93, but the gap between the ends 311 and each side surface 931 of the groove 93 is smaller than the diameter. Therefore, if a large amount of flux were to enter this gap, it could hinder the movement of the torch section 3 in the welding direction. As described above, in the welding apparatus 1, the height of the spray nozzles 32a to 32c is less than or equal to the height of the tips of the welding torches 31a and 31b, so that a large amount of flux does not enter the gap. As a result, it is possible to move the torch section 3 appropriately along the welding direction. In Figure 3, the flux 99 supplied into the groove 93 is shown by a dashed line.

[0029] As shown in Figures 1 and 2, two position adjustment parts 51a and 51b of the tracing mechanism 5 are fixed to both ends of the holding block 36 in the welding direction. Details of the position adjustment parts 51a and 51b will be described later. A base part 37 is positioned above the holding block 36. The base part 37 is a member that extends in the welding direction, and the holding block 36 is fixed to the base part 37 via two connecting plates 38 that are aligned in the welding direction. The longitudinal direction of the base part 37 is parallel to the torch arrangement direction. The wire feeding devices 33a and 33b described above are fixed to both ends of the base part 37 in the welding direction. In Figure 2, the wire feeding devices 33a and 33b are not shown. The holding block 36 and the base part 37 may be connected by a single connecting plate 38, or they may be formed integrally.

[0030] Figure 4 is a plan view showing the support section 4. In Figure 4, the torch section 3 is shown in a simplified manner. The support section 4 includes a connecting section 41. When viewed along the vertical direction, the connecting section 41 is L-shaped. A first rotation axis 43 extending in the vertical direction is provided at the (-X) end of the connecting section 41, and the L-shaped plate 232 of the stage 231, described later, is connected via the first rotation axis 43. The connecting section 41 is freely rotatable relative to the stage 231 about the first rotation axis 43. A second rotation axis 44 extending in the vertical direction is provided at the (+Y) end of the connecting section 41, and the base section 37 described above is connected via the second rotation axis 44. The base section 37 is freely rotatable relative to the connecting section 41 about the second rotation axis 44. In this way, the connecting portion 41 and the base portion 37 are configured as an open link mechanism, and the rotation of the connecting portion 41 around the first rotation axis 43 and the rotation of the base portion 37 around the second rotation axis 44 allows the torch portion 3 to move in a plane perpendicular to the vertical direction, and the inclination angle of the torch arrangement direction with respect to the welding direction can also be changed. In the support portion 4, by using an L-shaped connecting portion 41, it is possible to reduce the moment acting on the first rotation axis 43 while making the support portion 4 compact.

[0031] As shown in Figures 1 and 2, the moving mechanism 2 comprises a trolley 21, rails 22, and a two-axis stage 23. The rails 22 extend in the welding direction. The trolley 21 is a self-propelled trolley equipped with an electric motor and the like, and moves along the rails 22 in the welding direction. The two-axis stage 23 is fixed to the trolley 21. The two-axis stage 23 has a ball screw mechanism and an electric motor, and is capable of moving the moving body, stage 231, in the width direction and vertical direction. In the example of Figure 4, an L-shaped plate 232 is fixed to the stage 231, and the connecting part 41 is connected to the L-shaped plate 232. As previously described, a torch part 3 is connected to the connecting part 41, and as the trolley 21 moves in the welding direction, the torch part 3 also moves in the welding direction together with the trolley 21. In addition, the two-axis stage 23 allows the torch part 3 to move in the width direction and vertical direction together with the stage 231. The structure of the moving mechanism 2 can be modified in various ways, and a linear motor or the like may be used as the drive source.

[0032] As shown in Figure 1, a groove depth acquisition unit 6 is positioned on the (+X) side of the holding block 36. The groove depth acquisition unit 6 is fixed to the base unit 37 via a sensor support unit 61. The groove depth acquisition unit 6 is, for example, a laser sensor and has an emitter and a light receiver. The emitter irradiates the surface of the workpiece 91 with laser light, and the light receiver receives the reflected light reflected from the surface, thereby acquiring the distance to the bottom surface 932 of the groove 93. Other sensors may be used in the groove depth acquisition unit 6 as long as they can acquire the distance to the bottom surface 932 of the groove 93.

[0033] As previously described, the tracing mechanism 5 includes two position adjustment units 51a and 51b. Position adjustment unit 51a is located on the (+X) side of the leading spray nozzle 32a, and position adjustment unit 51b is located on the (-X) side of the trailing spray nozzle 32c. Position adjustment unit 51a passes each position of the groove 93 in the welding direction before the leading spray nozzle 32a, and position adjustment unit 51b passes the same position of the groove 93 after the trailing spray nozzle 32c. When viewed along the vertical direction as shown in Figure 4, position adjustment units 51a and 51b are located on the reference line K1 of the torch unit 3 (shown as a dashed line in Figure 4). In the following description, position adjustment units 51a and 51b will also be referred to as "leading position adjustment unit 51a" and "trailing position adjustment unit 51b," respectively.

[0034] Each position adjustment unit 51a, 51b mechanically conforms to the groove 93. As shown in Figure 1, the position adjustment units 51a, 51b each include a support shaft 511, a rotating mechanism 512, a contact roller support unit 513, and a pair of contact rollers 514. The support shaft 511 extends vertically, and in the example in Figure 1, its diameter gradually decreases from the top to the bottom. The upper end of the support shaft 511 is connected to the rotating mechanism 512. The rotating mechanism 512 rotates the support shaft 511 using compressed air as a driving source.

[0035] A contact roller support 513 is fixed to the lower end of the support shaft 511 (the end on the groove 93 side, hereinafter simply referred to as the "lower end"). The contact roller support 513 is a member that extends in a direction perpendicular to the support shaft 511. The width of the contact roller support 513 is approximately the same as the diameter of the lower end of the support shaft 511. A pair of contact rollers 514 are provided at both ends of the contact roller support 513. Preferably, the pair of contact rollers 514 are the same shape and size. When viewed along the vertical direction, the pair of contact rollers 514 and the support shaft 511 are aligned in a straight line, and the pair of contact rollers 514 are separated by the same distance from the support shaft 511. Each contact roller 514 is positioned below the contact roller support 513 and is supported by the contact roller support 513. The contact rollers 514 are cylindrical with a central axis approximately parallel to the vertical direction and are rotatable about this central axis. Furthermore, the shape and / or size of the pair of contact rollers 514 may differ. Also, the shape and / or size of the contact rollers 514 may differ between the leading position adjustment unit 51a and the trailing position adjustment unit 51b.

[0036] In the advance position adjustment section 51a, the upper end of the support shaft 511 protrudes upward from the rotation mechanism 512. As shown in Figures 1 and 4, a roller to be detected support section 516 is attached to this upper end. The roller to be detected support section 516 protrudes in a direction substantially perpendicular to the support shaft 511. A roller to be detected 517 is provided at the tip of the roller to be detected support section 516. The roller to be detected 517 is positioned above the roller to be detected support section 516 and is rotatable about a central axis substantially parallel to the vertical direction. The roller to be detected 517 also rotates together with the support shaft 511, and the position of the roller to be detected 517 in the width direction changes according to the rotation angle of the support shaft 511. In this embodiment, the diameter of the roller to be detected 517 is the same as that of the contact roller 514, and the roller to be detected 517 and one of the contact rollers 514 are positioned at the same location in the circumferential and radial directions with respect to the support shaft 511. Therefore, when viewed along the vertical direction, the entirety of the detected roller 517 overlaps with the entirety of one of the contact rollers 514, regardless of the rotation angle of the support shaft 511.

[0037] Figure 5 shows the configuration of the groove width acquisition unit 7. The groove width acquisition unit 7 comprises a contact-type displacement sensor 71 and a groove width calculation unit 70. The displacement sensor 71 is mounted on the holding block 36 (see Figure 1) and is positioned on the (-Y) side of the roller to be detected 517. The displacement sensor 71 is provided with a disc-shaped contact portion 72 that can move back and forth in the width direction, and the contact portion 72 faces the roller to be detected 517. In the displacement sensor 71, the contact portion 72 is biased with a weak force in the (+Y) direction, and the contact portion 72 is in constant contact with the roller to be detected 517. As a result, the position of the roller to be detected 517 in the width direction, more precisely, the position of the outer edge of the roller to be detected 517 furthest from the support shaft 511 in the width direction is measured. The measured value of the position of the roller to be detected 517 is output to the groove width calculation unit 70. As will be described later, the groove width calculation unit 70 calculates the width of the groove 93 from the position of the roller to be detected 517. The groove width calculation unit 70 may be implemented, for example, by a function of the computer in the control unit 10, in which case it can be considered that this function is shared by the groove width acquisition unit 7 and the control unit 10.

[0038] Next, the welding process of the workpiece 91 to the groove 93 by the welding apparatus 1 will be described. During the welding process, the torch unit 3 moves from the (-X) side to the (+X) side as the trolley 21 in Figure 1 moves, and the support shaft 511 of the leading position adjustment unit 51a, the leading spray nozzle 32a, the leading welding torch 31a, the intermediate spray nozzle 32b, the trailing welding torch 31b, the trailing spray nozzle 32c, and the support shaft 511 of the trailing position adjustment unit 51b pass through each position of the groove 93 in the welding direction in order. At this time, the control unit 10 controls the two-axis stage 23 based on the distance to the bottom surface 932 of the groove 93 acquired by the groove depth acquisition unit 6, and the distance between the tips of the welding torches 31a and 31b and the bottom surface 932 of the groove 93 is kept at a constant distance (for example, 30 to 40 mm). In other words, the height of the torch unit 3 is automatically adjusted. Furthermore, if a weld bead has been formed immediately beforehand, the bottom surface 932 of the groove 93 is the top surface of that weld bead. In the welding process, the torch arrangement direction and the base portion 37 are not necessarily parallel to the X direction (welding direction).

[0039] In each position adjustment section 51a and 51b, after the lower end of the support shaft 511 is positioned within the groove 93, the rotation mechanism 512 rotates the support shaft 511 using compressed air pressure. When one of the pair of contact rollers 514 contacts (presses against) one side surface 931 of the groove 93, the torch section 3 moves passively in the width direction, and the support shaft 511 rotates further. The other contact roller 514 then contacts the other side surface 931 of the groove 93. As a result, the support shaft 511 is positioned in the center between the two side surfaces 931 of the groove 93, as shown in Figure 6.

[0040] In practice, while the lower end of the support shaft 511 is positioned within the groove 93, the rotation mechanism 512 continuously applies rotational force to the support shaft 511. Therefore, even if the width of the groove 93 fluctuates, the pair of contact rollers 514 maintain contact with both sides 931 of the groove 93, and the support shaft 511 is automatically positioned in the center between the two sides 931 of the groove 93. Strictly speaking, the positions of the two sides 931 of the groove 93 that the pair of contact rollers 514 contact are shifted in the welding direction, but this shift is slight and therefore has very little effect on the tracing motion.

[0041] Furthermore, the longitudinal direction of the groove 93 may be inclined with respect to the X direction (the direction of movement of the trolley 21, which is the welding direction), or the groove 93 may meander along the X direction. Even in such cases, the torch arrangement direction of the torch section 3 is passively inclined with respect to the X direction, and the support shaft 511 of the leading position adjustment section 51a and the support shaft 511 of the trailing position adjustment section 51b are automatically positioned in the center between the two sides 931 of the groove 93. In other words, the reference line K1 of the torch section 3 is positioned in the center of the groove 93 in the width direction. This makes it possible to form an appropriate weld bead (i.e., a weld bead with suppressed defects) that spreads uniformly on both sides in the width direction within the groove 93.

[0042] As shown in Figure 1, the pair of contact rollers 514 in the leading position adjustment section 51a are positioned below the lower ends (spray openings 320) of the spray nozzles 32a to 32c and above the bottom surface 932 of the groove 93. Therefore, near the vertical position where the weld bead should be formed, the pair of contact rollers 514 in the leading position adjustment section 51a can be brought into contact with both sides 931 of the groove 93, making it possible to position the support shaft 511 in the center of the groove 93. On the other hand, the pair of contact rollers 514 in the trailing position adjustment section 51b are positioned above the lower ends of the spray nozzles 32a to 32c, making it possible to position the support shaft 511 in the center of the groove 93 without being affected by the flux sprayed onto the groove 93.

[0043] Furthermore, during the welding process, as shown in Figure 7, the position of the roller to be detected 517 in the width direction at each position of the groove 93 in the welding direction is acquired by the displacement sensor 71. In the groove width calculation unit 70 (see Figure 5), for example, the rotation angle of the support shaft 511 is determined from the position of the roller to be detected 517 in the width direction, and the width of the groove 93 at each position in the welding direction is calculated using this rotation angle. The groove width calculation unit 70 may have functions or tables that show the relationship between the position of the roller to be detected 517 in the width direction and the width of the groove 93 prepared in advance.

[0044] In this processing example, a reference table showing welding conditions that are less likely to cause welding defects for multiple widths of the groove 93 is determined in advance through experiments, etc., and stored in the control unit 10. The welding conditions are, for example, the current and voltage applied to the welding torches 31a and 31b. The control unit 10 determines the welding conditions at each position in the welding direction by referring to the reference table using the width of the groove 93 obtained by the groove width acquisition unit 7. Then, when the tips of the welding torches 31a and 31b reach that position, the current and voltage indicated by the welding conditions are applied to the welding torches 31a and 31b. Note that the movement speed of the torch unit 3 in the welding direction (welding speed) is included in the welding conditions, and in the welding process, the movement speed when welding at each position in the welding direction may be changed to match the width of the groove 93 at that position.

[0045] In the welding apparatus 1, the torch unit 3 moves from the (-X) end to the (+X) end of the groove 93, thereby forming a weld bead that extends across the entire groove 93 in the welding direction. When forming the next weld bead, the two-axis stage 23 moves the torch unit 3 upward, and then the trolley 21 moves to position the torch unit 3 on the (-X) side of the workpiece 91. After that, the weld bead is formed in the same manner as above. By repeating the weld bead formation a predetermined number of times, multiple layers of weld beads are stacked, and the welding process is completed.

[0046] In the welding apparatus 1 described above, a leading position adjustment unit 51a and a trailing position adjustment unit 51b are provided, but the tracing mechanism 5 may have only one position adjustment unit. For example, if the torch unit 3 has only one welding torch, it is possible to use only one position adjustment unit to position the welding torch (the reference position of the torch unit 3) approximately in the center of the groove 93 and to properly form a welding bead.

[0047] As described above, the welding apparatus 1 comprises a torch section 3, a support section 4, a moving mechanism 2, and a tracing mechanism 5. The torch section 3 performs welding on a groove 93 formed at the butt joint between the materials to be welded 91, extending in a predetermined longitudinal direction. The support section 4 supports the torch section 3 in a movable state in the width direction of the materials to be welded 91. The moving mechanism 2 moves the support section 4 together with the torch section 3 in the welding direction along the longitudinal direction. The tracing mechanism 5 is fixed to the torch section 3 and comprises a support shaft 511, a pair of contacts (contact rollers 514 in the above), and a rotating mechanism 512. The support shaft 511 extends along the depth direction (up and down direction in the above). The pair of contacts are attached to the end of the support shaft 511 on the groove 93 side and are arranged on both sides of the support shaft 511 when viewed along the support shaft 511. The rotating mechanism 512 rotates the support shaft 511 with its end inserted into the groove 93, thereby bringing the pair of contactors into contact with both sides 931 of the groove 93. This makes it easy for the tracing mechanism 5 to position the reference position of the torch portion 3 (in the above case, the reference line K1 of the torch portion 3) at the center of the groove 93 in the width direction, that is, the torch portion 3 can be easily made to conform to the groove 93. As a result, the welding apparatus 1 is able to form a desirable weld bead.

[0048] Preferably, each of the pair of contacts is a contact roller 514 that can rotate about a central axis along the support shaft 511. This allows the pair of contacts to move smoothly within the groove 93, and allows the torch portion 3 to conform more reliably to the groove 93. Depending on the design of the welding apparatus 1, the pair of contacts may be other than rollers, and may be sliding members that move along both sides 931 of the groove 93.

[0049] Preferably, the torch section 3 comprises a plurality of welding torches 31a, 31b arranged in an arrangement direction along the welding direction (torch arrangement direction in the above terminology). The support section 4 is capable of changing the inclination angle of the arrangement direction relative to the welding direction in a plane perpendicular to the depth direction. The tracing mechanism 5 comprises a position adjustment section 51a having a support shaft 511, a pair of contacts and a rotation mechanism 512, and another position adjustment section 51b having a structure similar to that of the position adjustment section 51a. With respect to the welding direction, the plurality of welding torches 31a, 31b are arranged between the position adjustment section 51a and the position adjustment section 51b. With this structure, the arrangement direction of the plurality of welding torches 31a, 31b can be tilted to match the inclination and meandering of the groove 93, thereby more reliably forming a desirable weld bead.

[0050] Preferably, the support portion 4 includes a connecting portion 41 that connects the movable body of the moving mechanism 2 (stage 231 in the above example) and the torch portion 3. The connecting portion 41 is rotatable with respect to the movable body about a first rotation axis 43 along the depth direction, and the torch portion 3 is rotatable with respect to the connecting portion 41 about a second rotation axis 44 along the depth direction. By rotating the connecting portion 41 around the first rotation axis 43 and the torch portion 3 around the second rotation axis 44, the torch portion 3 is movable in the width direction and the inclination angle in the above arrangement direction can be changed. In such a welding apparatus 1, the configuration of the support portion 4 can be simplified. The configuration of the support portion 4 may be arbitrarily changed, and for example, a sliding mechanism that allows the torch portion 3 to move in the width direction may be used.

[0051] Preferably, the welding apparatus 1 further comprises a groove width acquisition unit 7 and a control unit 10. The groove width acquisition unit 7 acquires the width of the groove 93 based on the rotation angle of the support shaft 511 when a pair of contactors are in contact with both sides 931 of the groove 93. The control unit 10 determines the welding conditions based on the output from the groove width acquisition unit 7. This makes it possible to perform welding using appropriate welding conditions based on the actual width of the groove 93, and to form a weld bead with suppressed defects. The computer realizing the control unit 10 may be located away from the main body of the welding apparatus 1, which includes the torch unit 3 and the moving mechanism 2. In this case, the computer may be connected to the main body of the welding apparatus 1 via a network such as the Internet, and the control unit 10 may be realized by cloud computing.

[0052] Preferably, the support shaft 511 of the tracing mechanism 5 is provided with a detection unit (in the above example, a detection roller 517) that protrudes from the support shaft 511, and the position of the detection unit in one direction perpendicular to the support shaft 511 changes according to the rotation angle of the support shaft 511. The groove width acquisition unit 7 acquires the width of the groove 93 by measuring the position of the detection unit in the said one direction. In such a welding apparatus 1, the width of the groove 93 can be easily acquired. Note that the detection unit may be something other than a roller.

[0053] Preferably, the torch unit 3 is provided with a flux spraying nozzle 32a for spraying flux and a welding torch 31a for performing welding, arranged along the welding direction. When welding the groove 93, the spraying nozzle 320 of the spraying nozzle 32a and the end 311 of the welding torch 31a are positioned within the groove 93, and the spraying nozzle 32a and the welding torch 31a pass sequentially through each position of the groove 93 in the welding direction. The width of the groove 93 is 2 times or less the diameter of the end 311 of the welding torch 31a, and the height from the bottom surface 932 of the groove 93 to the spraying nozzle 320 of the spraying nozzle 32a is 100% or less the height to the tip of the end 311 of the welding torch 31a. This prevents flux from getting stuck between the welding torch 31a and the side surface 931 of the groove 93, which would hinder the movement of the torch unit 3.

[0054] The welding apparatus 1 described above can be modified in various ways.

[0055] In the above embodiment, since the pair of contacts (contact rollers 514) are separated by the same distance from the support shaft 511, the reference position of the torch section 3 in the width direction is positioned at the center of the groove 93 (i.e., the predetermined position described later is the center of the groove 93). On the other hand, depending on the design of the welding apparatus 1, the first distance between one contact and the support shaft 511 may differ from the second distance between the other contact and the support shaft 511. In such a welding apparatus 1, it is possible to position the reference position of the torch section 3 at a predetermined position in the groove 93 in the width direction that corresponds to the ratio of the first distance to the second distance. In this case, for example, the welding torches 31a and 31b are positioned at positions offset from the reference position of the torch section 3 in the width direction so that the welding torches 31a and 31b are positioned at the center of the groove 93.

[0056] In the vertical direction, the position of the support shaft 511 to which the pair of contacts are attached may be a certain distance (+Z) from the tip of the support shaft 511, as long as the pair of contacts can contact both sides 931 of the groove 93. That is, the end of the support shaft 511 to which the pair of contacts are attached includes the portion of the support shaft 511 that is a certain distance from the tip of the support shaft 511. Furthermore, the pair of contacts may be positioned offset from each other in the vertical direction.

[0057] In the above embodiment, the detected roller 517 is positioned at the same location as the contact roller 514 when viewed along the support shaft 511. However, as shown in Figure 8, the detected roller 517 may be positioned at a different location from the contact roller 514. In the example in Figure 8, the detected roller 517 is positioned at an angle 90° offset from the contact roller 514 with respect to the support shaft 511. In this case, the longitudinal direction of the displacement sensor 71 can be made substantially parallel to the welding direction, and the widthwise size of the configuration attached to the torch section 3 can be reduced.

[0058] In the above embodiment, the roller to be detected 517 is positioned outside the groove 93, but depending on the width of the groove 93, the roller to be detected 517 may be positioned inside the groove 93.

[0059] In the groove width acquisition unit 7, a contact-type displacement sensor 71 is provided, but other types of sensors may be used as long as the displacement of the roller to be detected 517 can be acquired. In addition, in the groove width acquisition unit 7, the rotation angle of the support shaft 511 may be acquired by attaching a rotary encoder or the like to the support shaft 511. The groove width acquisition unit 7, which acquires the width of the groove 93 based on the rotation angle of the support shaft 511, can be realized in various forms.

[0060] The number of welding torches may be one or three or more. Even in this case, the welding apparatus 1 having the tracing mechanism 5 described above makes it possible to easily make the torch portion 3 conform to the groove 93 and form a desirable weld bead. For example, when there is one welding torch, it is preferable to provide spray nozzles in front of and behind the welding torch in the welding direction. The number of spray nozzles may also be appropriately changed in accordance with the number of welding torches.

[0061] In the welding apparatus 1, one layer of the weld may be formed by multiple passes. In this case, for example, by shifting the positions of the welding torches 31a and 31b in the width direction with respect to the reference line K1 of the torch section 3 for each pass, it is possible to form a weld bead in each pass at a position shifted by a desired distance from the center of the groove 93.

[0062] The moving mechanism 2 does not necessarily have to be a mechanism that moves the support part 4 and the torch part 3; it may also be a mechanism that moves the workpiece 91 in the welding direction. In other words, the moving mechanism 2 only needs to move the support part 4 and the torch part 3 relative to the workpiece 91 in the welding direction.

[0063] The material to be welded 91 may have various shapes, such as a roughly flat plate or a roughly cylindrical shape. Furthermore, multiple welding devices 1 may be provided, and welding may be performed in parallel (simultaneously) on one or more grooves 93. In this case, the welding conditions in the multiple welding devices 1 may be the same or different.

[0064] The configurations in the above embodiments and each modified example may be combined as appropriate, as long as they do not contradict each other. [Explanation of Symbols]

[0065] 1. Welding equipment 2 Moving mechanism 3 Torch section 4 Support part 5. Copying mechanism 7 Groove width acquisition section 10 Control Unit 31a, 31b Welding Torch 32a~32c Spray nozzle 41 Connecting part 43. First rotation axis 44. Second rotation axis 51a,51b Position adjustment section 91 Material to be welded 93 Bevel 99 Flux 231 Stages 311 (End of welding torch) 320 Spray port 511 Support shaft 512 Rotation mechanism 514 Contact Roller 517 Detected roller 931 (Bevel) Side 932 (Bevel) bottom K1 Reference Line

Claims

1. A welding apparatus, A torch section for welding is formed in a groove extending in a predetermined longitudinal direction at the butt joint between the materials to be welded, A support portion that supports the torch portion in a manner that allows it to move in the width direction of the arrangement of the materials to be welded, A moving mechanism that moves the support portion together with the torch portion relative to the workpiece in the welding direction along the longitudinal direction, A tracing mechanism is fixed to the torch portion and positions the reference position of the torch portion at a predetermined position in the groove in the width direction, Equipped with, The aforementioned copying mechanism, A support shaft extending along the depth direction of the groove, A pair of contacts are attached to the grooved end of the support shaft and are arranged on both sides of the support shaft when viewed along the support shaft, With the end of the support shaft inserted into the groove, a rotation mechanism is provided to rotate the support shaft, thereby bringing the pair of contactors into contact with both sides of the groove, respectively. A welding apparatus equipped with the following features.

2. A welding apparatus according to claim 1, The predetermined position of the groove in the width direction is the center of the groove, A welding apparatus in which the pair of contacts are separated by the same distance from the support shaft.

3. A welding apparatus according to claim 1, A welding apparatus in which each of the pair of contacts is a roller that can rotate about a central axis along the support shaft.

4. A welding apparatus according to claim 1, The torch section comprises a plurality of welding torches arranged in an arrangement direction along the welding direction, The support portion is capable of changing the inclination angle of the arrangement direction with respect to the welding direction in a plane perpendicular to the depth direction, The aforementioned copying mechanism, The position adjustment unit having the support shaft, the pair of contacts, and the rotation mechanism, Another position adjustment unit having a structure similar to the aforementioned position adjustment unit, Equipped with, A welding apparatus in which the plurality of welding torches are arranged between the position adjustment unit and the other position adjustment unit with respect to the welding direction.

5. A welding apparatus according to claim 4, The support portion includes a connecting portion that connects the moving body of the moving mechanism and the torch portion, The connecting portion is rotatable with respect to the moving body about a first rotation axis along the depth direction, and the torch portion is rotatable with respect to the connecting portion about a second rotation axis along the depth direction. A welding apparatus in which the torch portion is movable in the width direction and the inclination angle in the arrangement direction is changeable by the rotation of the connecting portion around the first rotation axis and the rotation of the torch portion around the second rotation axis.

6. A welding apparatus according to any one of claims 1 to 5, A groove width acquisition unit that acquires the width of the groove based on the rotation angle of the support shaft when the pair of contactors are in contact with both sides of the groove, A control unit that determines welding conditions based on the output from the groove width acquisition unit, A welding device that also includes additional features.

7. A welding apparatus according to claim 6, In the support shaft of the aforementioned tracing mechanism, a detection portion is provided that protrudes from the support shaft, The position of the detected part in a direction perpendicular to the support shaft changes according to the rotation angle of the support shaft. A welding apparatus that obtains the width of a groove by having the groove width acquisition unit measure the position of the detected part in the one direction.

8. A welding apparatus according to any one of claims 1 to 5, In the torch section, a spray nozzle for spraying flux and a welding torch for performing welding are provided along the welding direction. During welding of the groove, the spray nozzle opening and the end of the welding torch are positioned within the groove, and the spray nozzle and the welding torch sequentially pass through each position of the groove in the welding direction. The width of the groove is no more than twice the diameter of the end of the welding torch. A welding apparatus in which the height from the bottom surface of the groove to the spray opening of the spray nozzle is less than or equal to the height from the tip of the end of the welding torch.

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