Welding device

Abstract

To provide a welding device which achieves high accuracy in setting of a position to which a welded object, such as a stud bolt, is welded.SOLUTION: A welding device (1) welds a stud bolt (B) to an upper surface (W1) formed with an opening (W2) of a workpiece (W). The welding device includes: a welding unit (20) which holds the stud bolt to weld the stud bolt to the upper surface of the workpiece; a movement unit (40) which moves the welding unit and the stud bolt held by the welding unit to a welding position; an opening imaging unit (50) which captures images of a formation edge (W3) of the opening in the workpiece; a position specification unit (75) which specifies the welding position of the stud bolt on the basis of opening image data output from the opening imaging unit; and a movement control unit (77) which controls movement of the movement unit on the basis of the welding position specified by the position specification unit.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a welding device capable of welding a workpiece to a welding object. [Background technology]

[0002] Patent Document 1 discloses an automatic welding system that welds a design panel and a reinforcing member, which are workpieces to be welded. In Patent Document 1, the lower left corner of the design panel is used as the origin, and two orthogonal directions are used as coordinate axes. The corner of the reinforcing member is photographed with a camera and image processing is performed to extract edges, thereby determining the actual installation position coordinate of the corner of the reinforcing member. In Patent Document 1, the difference between the actual installation position coordinate and the correct installation position coordinate is identified as an installation error, and a corrected welding position is calculated based on the installation error. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Republished WO2020 / 137184 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, because the reinforcing member is pre-installed on the design panel and then welded, if there is a large amount of installation error, an error is detected and the installation position of the reinforcing member cannot be corrected. Furthermore, in Patent Document 1, the origin is set to the lower left corner, which is the outer edge of the design panel, so as the design panel becomes larger, the distance from the origin to the welding position becomes longer, which is a problem as the design panel becomes larger, resulting in a larger error in the actual welding position.

[0005] The present invention has been made in view of the above points, and one of its objects is to provide a welding device that can improve the accuracy of the position at which the workpieces are welded. [Means for solving the problem]

[0006] One embodiment of the welding apparatus of the present invention is a welding apparatus that welds a welding object to a welding surface where an opening is formed in a workpiece, and is characterized in that it comprises: a welding unit that holds the welding object and welds it to the welding surface; a moving unit that moves the welding unit and the welding object held by the welding unit to a welding position; an opening imaging unit that images the edge of the opening; a position identification unit that identifies the welding position of the welding object based on opening imaging data output from the opening imaging unit; and a movement control unit that controls the movement of the moving unit based on the welding position identified by the position identification unit. [Effects of the Invention]

[0007] According to the present invention, the welding portion can be moved via the moving portion while holding the workpiece. In other words, the welding portion and the moving portion can move the workpiece to the welding position identified by the position identifying portion, and welding can be performed after the position adjustment is completed. This avoids the conventional problem of a large installation error between the panel and the reinforcing member that cannot be corrected, and allows the workpiece to be welded with high precision. Furthermore, since the welding position is identified based on the aperture image data, the welding position can be identified based on its relative position with respect to the opening in the workpiece. In other words, the forming edge whose relative position is calculated to identify the welding position can be the opening, which can be closer to the welding position than the conventional case in which the opening is the corner of the panel. This allows the precision of the welding position of the workpiece to be maintained even when the workpiece is large. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic plan view of a welding device according to an embodiment. [Figure 2] 1 is a schematic front view of a welding device according to an embodiment. [Figure 3] FIG. 2 is a schematic perspective view of the welded portion and the vicinity of the aperture imaging portion according to the embodiment. [Figure 4] FIG. 2 is a side view of the welded portion and the vicinity of the aperture imaging portion according to the embodiment. [Figure 5] FIG. 2 is a partial front cross-sectional view of a welded portion according to an embodiment. [Figure 6] 1 is a block diagram showing a configuration of a welding device according to an embodiment; [Figure 7] 5A to 5C are explanatory diagrams showing the flow of welding a stud bolt in an embodiment. [Figure 8] FIG. 1 is a plan view showing an example of a workpiece according to an embodiment. [Figure 9] 3 is a flowchart showing the flow of a welding method of the welding device according to the embodiment. [Figure 10] 3 is a flowchart showing the flow of a welding method of the welding device according to the embodiment. [Figure 11] FIG. 10 is a plan view showing another example of a workpiece. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiments, and can be implemented by appropriate modifications within the scope of the present invention. For the sake of convenience, some components may be omitted in the following drawings.

[0010] In the following description, the X, Y, and Z directions indicated by arrows in each figure will be used as references. The X and Y directions are approximately horizontal, and the Z direction is the up-down direction (vertical direction). Of the two arrows indicating the X direction, the +X side is the right side, and the -X side is the left side. Of the two arrows indicating the Y direction, the +Y side is the front side, and the -Y side is the rear side. Of the two arrows indicating the Z direction, the +Z side is the up side, and the -Z side is the down side. These directions are merely examples set for the sake of convenience, and in practice, the X direction in the figures can be changed to any direction, such as being tilted relative to the left-right direction or the front-to-back direction.

[0011] Fig. 1 is a schematic plan view of a welding apparatus according to an embodiment. Fig. 2 is a schematic front view of a welding apparatus according to an embodiment. As shown in Figs. 1 and 2, welding apparatus 1 is an apparatus for welding a plurality of stud bolts B, which are to be welded, to an upper surface W1 of a workpiece W. In Figs. 1 and 2, two workpieces W are arranged side by side in the X direction. The workpieces W are not particularly limited, but in this embodiment, they are made of steel plate members used for the walls and panels of electric power equipment such as transformers, switchgears, distribution boards, and uninterruptible power supplies (UPS).

[0012] In this embodiment, the workpiece W is welded with its thickness oriented in the vertical direction, and the upper surface W1 is formed as the welding surface. More specifically, the lower end of a stud bolt B, whose axis is oriented in the vertical direction, is welded to the upper surface W1 of the workpiece W.

[0013] The workpiece W also has a single opening W2 formed in a generally rectangular opening shape on its upper surface W1. In this embodiment, a position offset by a predetermined width from the outer edge of the workpiece W is formed as a forming edge W3 of the opening W2. This forming edge W3 has four corner portions W31 of the rectangle formed in a quadrant arc shape. Furthermore, in this embodiment, stud bolts B are welded in a row at predetermined intervals on positions offset by a predetermined width outward from the opening W2.

[0014] The welding apparatus 1 comprises a pair of first frames 3 arranged on both sides in the X direction and extending in the Y direction, a second frame 4 disposed on the +Y side between the pair of first frames 3, and a carriage 5 on which two workpieces W are placed between the pair of first frames 3. A plurality of stud bolts B are arranged side by side on the second frame 4, forming a stud bolt (workpiece to be welded) supply section. The carriage 5 is provided on the front side (-Y side) of the welding apparatus 1 so as to be able to move in and out between the pair of first frames 3.

[0015] The welding device 1 is also provided with an overall imaging unit 7 such as a camera that images all of the workpieces W on the carriage 5 and outputs the images as overall imaging data. The overall imaging unit 7 is supported above the end of the second frame 4 on the +Y side via a frame (not shown) or the like, and is disposed so that the workpieces W fit within the imaging field of view. The overall imaging unit 7 may be configured to image the entirety of at least one workpiece W among the multiple workpieces W.

[0016] Furthermore, the welding device 1 includes a welding unit 20 that holds the stud bolt B and welds it to the top surface W1 of the workpiece W, a moving unit 40 that moves the welding unit 20 and the stud bolt B held by the welding unit 20 to the welding position, and an opening imaging unit 50 that images the edge W3 of the opening W2 in the workpiece W. The moving unit 40, welding unit 20, and opening imaging unit 50 will be described below in that order.

[0017] The moving unit 40 may be, for example, a three-axis robot. Specifically, the moving unit 40 includes a Z-axis moving mechanism 41 that supports the welded portion 20 and the aperture imaging unit 50 so that they can move in the Z direction, an X-axis moving mechanism 42 that supports the Z-axis moving mechanism 41 so that they can move in the X direction, and a Y-axis moving mechanism 43 that supports the X-axis moving mechanism 42 so that they can move in the Y direction. The Y-axis moving mechanism 43 is installed on a pair of first frames 3, so that the moving unit 40, the welded portion 20, and the aperture imaging unit 50 are supported from below by the first frames 3.

[0018] Each of the moving mechanisms 41 to 43 can be, for example, a cylinder, a direct-acting motor, a linear motor, a feed screw structure, or a mechanism combining two or more of these. Also, instead of each of the moving mechanisms 41 to 43, the moving unit 40 may be configured with an articulated robot or the like.

[0019] Fig. 3 is a schematic perspective view of the welding portion and the aperture imaging unit and its surroundings according to the embodiment. Fig. 4 is a side view of the welding portion and the aperture imaging unit and its surroundings according to the embodiment. As shown in Figs. 3 and 4, welding portion 20 includes a device main body 21 configured similarly to a so-called welding gun, a ferrule holding portion 22 that holds a ferrule F, and a ferrule lifting portion 23 that moves ferrule F up and down together with ferrule holding portion 22.

[0020] The ferrule F is a cylindrical body made of porcelain and is formed so that the stud bolt B can be inserted therethrough. The welding portion 20 is attached to a bracket 25 on the +Y side, and the bracket 25 is supported by a Z-axis movement mechanism 41 (see FIG. 1).

[0021] The device body 21 is connected to a welding power source (not shown) via a cable C. The device body 21 is equipped with a chuck 26 to which current supplied from the welding power source flows, and the chuck 26 also functions as an electrode for passing current through the stud bolt B.

[0022] Fig. 5 is a partial front cross-sectional view of a welded portion according to an embodiment. As shown in Fig. 5, the chuck 26 is formed in a cylindrical shape into which the stud bolt B is inserted, and is formed into a shape divided in the circumferential direction by a slit 26a. The chuck 26 also has a tapered surface 26b on its outer circumferential surface that gradually increases in diameter downward.

[0023] The welding portion 20 further includes a chuck operating portion 28 for holding the stud bolt B with the chuck 26.

[0024] The chuck operation unit 28 includes a pressure plate 29 having a tapered hole 29a through which the chuck 26 is inserted, and a connecting body 30 having a hole 30a through which the chuck 26 is inserted while supporting the pressure plate 29 from above. The chuck operation unit 28 also includes a drive mechanism 31 that supports the -X side region of the connecting body 30 from above. The drive mechanism 31 is configured with a cylinder or the like, and is provided so as to be able to drive (raise and lower) the connecting body 30 and the pressure plate 29 in the Z direction.

[0025] The tapered hole 29a of the presser plate 29 is formed with an inner peripheral shape that corresponds to the tapered surface 26b of the chuck 26. Therefore, in the chuck operation unit 28, by driving the drive mechanism 31 to lower the presser plate 29, the tapered hole 29a can slide with the tapered surface 26b of the chuck 26 in surface contact. This sliding applies a diameter-reducing force to the chuck 26, allowing the chuck 26 to tighten and grip the stud bolt B from the radial direction, and maintaining contact between the chuck 26 and the stud bolt B makes it possible to maintain electrical conduction. Furthermore, by raising the presser plate 29 and separating the tapered hole 29a of the presser plate 29 from the tapered surface 26b of the chuck 26, the tightening of the stud bolt B by the chuck 26 is released.

[0026] 3, the ferrule holding section 22 includes a pair of gripping members 33 arranged on both sides in the X direction of the stud bolt B held by the chuck 26, and a drive mechanism 34 that supports the pair of gripping members 33. The drive mechanism 34 is configured with a cylinder or the like, and drives the pair of gripping members 33 in directions that move them closer and farther apart in the X direction. This drive enables the ferrule holding section 22 to hold the ferrule F by clamping it between the pair of gripping members 33.

[0027] The ferrule lifting unit 23 is disposed on the +X side of the device body 21, attached to a bracket 25, and is configured by a cylinder or the like that supports the ferrule holding unit 22 from above.

[0028] The opening imaging unit 50 is attached to the bracket 25 via an arm member 51, and is provided so as to be able to image the workpiece W near the welded portion 20 and in front of the welded portion 20 (on the -Y side). The opening imaging unit 50 is composed of a camera or the like that images the edge W3 of the opening W2 and outputs the image as opening imaging data. In addition, a height detection unit 54 is attached to the arm member 51 behind the opening imaging unit 50 (on the +Y side). The height detection unit 54 is composed of a laser sensor or the like that detects the height position of the top surface W1 of the workpiece W and outputs the height data. The opening imaging unit 50 and the height detection unit 54 are provided so as to be movable together with the welded portion 20 by the moving unit 40.

[0029] Fig. 6 is a functional block diagram of a welding apparatus according to an embodiment. As shown in Fig. 6, welding apparatus 1 is equipped with a control device 70 that controls each part of welding apparatus 1, including welding unit 20, moving unit 40, and each imaging unit 7, 50. Control device 70 comprehensively controls each part of welding apparatus 1 and is configured to include a processor that executes various processes, a memory, etc. The memory is configured with one or more storage media, such as a ROM (Read Only Memory) or a RAM (Random Access Memory), depending on the application.

[0030] The control device 70 functions as a graphic data conversion unit 72, a workpiece measurement unit 73, a position identification unit 75, a memory unit 76, and a movement control unit 77. Note that the functional blocks of the control device 70 shown in Fig. 6 only show the configuration related to the present invention, and other configurations are omitted. Furthermore, with regard to the operation of each part of the welding device 1 described below, unless a control entity is specified, it is assumed that the operation is controlled by a control signal sent from the control device 70.

[0031] Here, an input unit 56 is connected to the control device 70. The input unit 56 acquires graphic data such as CAD data of the workpiece W, various welding conditions, and the like. The input unit 56 includes, for example, a keyboard, buttons, keys, a touch panel display, a microphone, and the like, and acquires data from operations by an operator or the like and outputs the data to the storage unit 76. The input unit 56 may also function as a communication interface to acquire data from an external device such as a personal computer via wired or wireless communication, or may be an interface such as a slot to which a storage medium such as a memory card containing data can be connected.

[0032] The graphic data conversion unit 72 performs processing to divide and extract elements such as lines, arcs, and circles that form the outline of the workpiece W and the opening W2 from the graphic data of the workpiece W. Then, based on the extracted elements, it calculates the coordinates of the center position of the opening W2 and the inclination of the opening W2 relative to the X and Y directions, and calculates the "reference welding position" of the stud bolt B, which is the relative position to the center position.

[0033] The graphic data conversion unit 72 then calculates position data that includes the calculated inclination of the opening W2 and the reference welding position of the stud bolt B. The reference welding position in the position data is the regular welding position used in the manufacturing stage. For example, for the workpiece W in FIG. 1, the reference welding positions in the position data are set in a row at multiple locations offset outward from the opening W2 by a predetermined width.

[0034] The workpiece measuring unit 73 calculates the workpiece measurement reference position of the workpiece W and the inclination of the entire workpiece W relative to the X and Y directions based on the overall image data of the workpiece W captured by the overall image capturing unit 7.

[0035] The position identifying unit 75 identifies the welding position of the stud bolt B based on the opening image capture data output from the opening image capture unit 50. Specifically, by performing appropriate image processing on the opening image capture data, the position identifying unit 75 calculates the center position of the opening W2 based on the opening image capture data, and compares this center position with the center position of the opening W2 included in the position data. Based on this comparison, the position data is corrected to calculate a corrected welding position, and the corrected welding position is identified as the welding position of the stud bolt B.

[0036] The memory unit 76 stores, via a storage medium such as RAM, graphic data input from the input unit 56, position data calculated by the graphic data conversion unit 72, and welding positions identified by the position identification unit 75. The memory unit 76 also stores programs for each unit of the control device 70 to perform various calculations and controls, as well as programs, data, etc. for functioning as applications.

[0037] The movement control unit 77 controls the movement amount of each of the movement mechanisms 41 to 43 of the movement unit 40 based on the welding position identified by the position identifying unit 75.

[0038] Next, the procedure for welding the stud bolt B using the welded portion 20 will be described with reference to Fig. 7. Fig. 7 is an explanatory diagram showing the flow of welding the stud bolt in the embodiment.

[0039] 7A, a stud bolt B is held by a chuck 26, and a ferrule F, into which the stud bolt B is inserted, is gripped by the ferrule holding part 22. In this state, the ferrule F is placed at or near the upper limit position via the ferrule lifting part 23, and the stud bolt B is set to protrude significantly from the underside of the ferrule F.

[0040] 7B, the ferrule holding part 22 is lowered via the ferrule lifting part 23, and the height of the ferrule holding part 22 and the ferrule F is adjusted. This adjustment sets the stud bolt B to a predetermined protrusion amount (for example, 4 mm) from the lower surface of the ferrule F.

[0041] Thereafter, the welding portion 20 is moved by the moving portion 40 (see FIG. 2), and is lowered by the Z-axis moving mechanism 41 (see FIG. 2) to a position directly above the predetermined welding position. At this time, as shown in FIG. 7C, the welding portion 20 is pushed in until there is no gap between the upper surface W1 of the workpiece W and the lower surface of the ferrule F. Then, by passing current through the welding portion 20, an arc is generated between the stud bolt B and the workpiece W inside the ferrule F, and they melt together and are welded.

[0042] After welding, the stud bolt B is released from the chuck operating portion 28 and the chuck 26, and the stud bolt B is released from the ferrule holding portion 22, and the welding portion 20 is raised and withdrawn as shown in FIG. 7D.

[0043] Next, a welding method for welding a plurality of stud bolts B to a workpiece W using the above-mentioned welding procedure will be described with reference to Figs. 8 to 10. Fig. 8 is a plan view showing an example of a workpiece according to an embodiment. Figs. 9 and 10 are flowcharts showing the flow of the welding method using the above-mentioned welding device. Below, an example will be described in which 36 (a plurality of) stud bolts B are welded to the workpiece W shown in Fig. 8.

[0044] 9, in step S01, graphic data such as CAD data of the workpieces W is stored in the memory unit 76 of the control device 70 via the input unit 56. Also, the number of workpieces W to be placed on the carriage 5 of the welding device 1 ("2" in the state of FIG. 1) is stored.

[0045] The stored graphic data includes at least the outer shape of the workpiece W, the edge W3 of the opening W2, and the shapes and positional information of all stud bolts B, as shown in Figure 8. In the graphic data, the stud bolts B are represented as circles with a predetermined diameter.

[0046] In step S02, the graphic data conversion unit 72 of the control device 70 performs a process of calculating "position data" of the workpiece W from the graphic data. In this process, first, the graphic data of the opening W2 (forming edge W3) and the stud bolt B in the workpiece W is divided into straight lines, arcs, and circles, and four arcs corresponding to the corner portion W31 and 36 circles corresponding to the stud bolt B are extracted. Then, the coordinates of the center points of the circles forming the four arcs are calculated, and based on the coordinates of the four center points, the coordinates of the center position of the opening W2 and the inclination of the opening W2 with respect to the X and Y directions are calculated.

[0047] Furthermore, in the processing of the graphic data conversion unit 72, the coordinates of the center points of each of the 36 circles are calculated. Furthermore, for each of the calculated coordinates of the 36 center points, the relative coordinates with respect to the coordinates of the center position of the opening W2 are calculated, and these relative coordinates are converted into the "reference welding position" of the stud bolt B. Therefore, the position data for the opening W2 in FIG. 8 includes the coordinates of the center position of the opening W2 and the coordinates of the reference welding position of the stud bolt B, which is set based on the position relative to the coordinates of the center position. Furthermore, this position data includes the calculated inclination of the opening W2 with respect to the X and Y directions. The calculated position data is stored in the memory unit 76 of the control device 70.

[0048] In step S03, the entire workpiece W on the carriage 5 is imaged by the overall imaging unit 7, and the image is output (acquired) as overall imaging data to the workpiece measuring unit 73 of the control device 70. The workpiece measuring unit 73 calculates a workpiece measurement reference position based on the overall imaging data of the workpiece W.

[0049] In step S04, the height position of the upper surface W1 of the workpiece W is detected at a plurality of locations on the upper surface W1 by the height detection unit 54, and the height data is output to the workpiece measurement unit 73 of the control device 70. At this time, the height detection unit 54 is moved to a position directly above a plurality of locations on the upper surface W1 of the workpiece W (for example, at predetermined intervals in the X and Y directions) via the movement unit 40 controlled by the movement control unit 77 of the control device 70.

[0050] In step S05, the workpiece measuring unit 73 of the control device 70 calculates the inclination of the entire workpiece W relative to the X and Y directions based on the overall image data of the workpiece W. Also in step S05, the height position of the opening imaging unit 50 that allows good imaging when imaging is performed by the opening imaging unit 50 in step S06, which will be described later, is calculated and stored in the storage unit 76.

[0051] In step S06, the aperture imaging unit 50 images the peripheries of the four corner portions W31, and outputs (acquires) the images as "aperture imaging data" to the position identification unit 75 of the control device 70. Such imaging is performed for each of the four corner portions W31.

[0052] At this time, the moving unit 40 is driven and controlled by the movement control unit 77 so that the center of the camera of the aperture imaging unit 50 is positioned directly above the center point of the arc of the corner portion W31 included in the position data stored in the memory unit 76 of the control device 70. As a result, the imaging range of the aperture imaging unit 50 shown by the two-dot chain line in Fig. 8 is set so that the corner portion W31 is positioned at the center at each of the four corner portions W31. In addition, the Z-axis moving mechanism 41 of the moving unit 40 is driven and controlled so that the aperture imaging unit 50 is positioned at the height position calculated in step S05.

[0053] In step S07, the position identification unit 75 of the control device 70 acquires point cloud or contour information from the aperture imaging data of the four corner portions W31, and calculates the two-dimensional position and orientation (posture) of each corner portion W31. Any method can be used for this calculation. The position identification unit 75 then calculates the coordinates of the center points of the arcs of each corner portion W31. Based on the coordinates of the four center points, the position identification unit 75 calculates the coordinates of the center position of the aperture W2 based on the aperture imaging data and the tilt with respect to each of the X and Y directions.

[0054] In step S08, the position identification unit 75 of the control device 70 compares the coordinates of the center position of the opening W2 calculated based on the opening image data with the coordinates of the center position of the opening W2 in the position data. Also in step S08, the tilt of the opening W2 calculated based on the opening image data is compared with the tilt of the opening W2 relative to the X and Y directions in the position data. Based on this comparison, the difference in the coordinates of the center positions of the two and the difference in tilt relative to the X and Y directions are calculated, and the reference welding position of the stud bolt B in the position data is corrected according to these differences. The position identification unit 75 determines the calculation result of this correction as the "corrected welding position," and identifies it as the "welding position" of the stud bolt B to be used for control in step S09, which will be described later.

[0055] In step S09, under the control of the movement control unit 77 of the control device 70, the movement unit 40 is driven to move the welding portion 20 onto the second frame 4, and the stud bolt B and the ferrule F are held by the welding portion 20. Thereafter, the movement control unit 77 controls the movement of the movement unit 40 based on the welding position identified in step S08, and the welding portion 20 is positioned directly above the welding position.

[0056] In step S10, after step S09 is performed, the stud bolt B is welded to the upper surface W1 of the workpiece W by the welding procedure described above (see FIG. 7).

[0057] In step S11, after step S10 has been carried out, the control device 70 determines whether welding of all of the stud bolts B, whose welding positions were identified in step S08, has been completed. If welding of all of the stud bolts B has not been completed (step S11: No), the process returns to step S09, and the welding portion 20 is moved via the moving unit 40 to weld the next stud bolt B. If welding of all of the stud bolts B has been completed (step S11: Yes), the process proceeds to step S12. Steps S09 and S10 are repeated until welding of all of the stud bolts B, whose welding positions were identified by their relative positions with respect to the opening W2 contained in the opening image capture data, has been completed. In this embodiment, there are 36 stud bolts B, and therefore this process is repeated 36 times.

[0058] In step S12, after step S11 is performed, the control device 70 determines whether welding has been completed for all of the openings W2 whose welding positions were identified in step S08. If welding has not been completed for all of the openings W2 (step S12: No), the process returns to step S06, where an image of the opening W2 to which the stud bolt B will next be welded is taken to obtain opening image data. If welding has been completed for all of the openings W2 in the workpiece W (step S12: Yes), the process proceeds to step S13. Steps S06 to S11 are repeated until welding has been completed for all of the openings W2 in the workpiece W. In the present embodiment, since there is only one opening W2, this repetition is not performed.

[0059] In step S13, after step S12 is performed, the control device 70 determines whether welding has been completed for all of the workpieces W on the carriage 5 (see FIG. 1). If welding has not been completed for all of the workpieces W (step S13: No), the process returns to step S04, and the height of the upper surface W1 of the workpiece W to which the stud bolt B will next be welded is detected. If welding has been completed for all of the workpieces W (step S13: Yes), welding ends. Steps S04 to S12 are repeated until welding has been completed for all of the workpieces W. In this embodiment, since there are two workpieces W, this repetition is performed twice.

[0060] As described above, according to the above embodiment, the stud bolt B, which is the workpiece to be welded, is held by the welding part 20, and the position of the stud bolt B can be adjusted by moving it together with the welding part 20 via the moving part 40. This makes it possible to improve the positional accuracy of welding the workpiece (stud bolt B) compared to conventional configurations in which the workpiece is placed in advance and then welded with a welding gun or the like.

[0061] Furthermore, in the above embodiment, the position identifying unit 75 identifies the welding position based on the opening image data, and identifies the welding position of the stud bolt B based on its relative position to the opening W2. This allows the formed edge W3 of the opening W2 to be the reference formed edge for calculating the relative position to identify the welding position, providing greater freedom in selecting the reference formed edge compared to the conventional case where a corner of the panel is used. Therefore, even if the workpiece W is large, it becomes easier to shorten the distance between the reference formed edge and the calculated welding position of the stud bolt B, improving the positional accuracy of welding the stud bolt B.

[0062] Furthermore, the position specifying unit 75 corrects the reference welding position of the position data stored in the memory unit 76 in accordance with the opening image capture data to specify the welding position of the stud bolt B. This allows the position data to be corrected in accordance with the position and inclination of the opening W2 calculated by processing the opening image capture data, thereby improving the positional accuracy for welding the stud bolt B.

[0063] Furthermore, the position identifying unit 75 compares the center position of the opening W2 calculated based on the opening image capture data with the center position of the opening W2 included in the position data to identify the welding position of the stud bolt B. This makes it possible to correct the reference welding positions of multiple stud bolts B by comparing the two center positions and identify the welding positions of the stud bolts B, thereby reducing the processing load for correction.

[0064] Furthermore, since the aperture imaging unit 50 and the height detection unit 54 can be moved by the moving unit 40 together with the welding portion 20, images and data can be acquired in the vicinity of the welding position at the welding portion 20. This improves the accuracy of the welding position identified using such images and the like.

[0065] The embodiments of the present invention are not limited to the above-described embodiments, and may be variously changed, substituted, or modified without departing from the spirit and scope of the technical idea of ​​the present invention. Furthermore, if the technical idea of ​​the present invention can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention.

[0066] 1 and 8 are merely examples, and as another example of the workpiece W, a workpiece W having a shape shown in Fig. 11 can also be welded by the welding device 1. Fig. 11 is a plan view showing another example of the workpiece.

[0067] The workpiece W in FIG. 11 has a plurality of openings W21 to W24, and for example, the stud bolts B arranged at a position offset by a predetermined width from the rectangular opening W21 located in the center in the Y direction can be welded in the same manner as the welding method described above.

[0068] On the other hand, for the circular openings W22 to W24, although the center position can be calculated in the same manner as described above, the tilt relative to the X and Y directions cannot be calculated even if one of the openings W22 to W24 is imaged.

[0069] Therefore, for example, if three circular openings W22 are lined up in the X direction, the three openings W22 are included in one opening image data by the opening image capture unit 50 in step S06 described above. Then, in step S07, the position identification unit 75 calculates the coordinates of the center points of the three openings W22, and the inclinations of the three lined up openings W22 with respect to the X direction and the Y direction are calculated using the coordinates of the three center points. As a result, in step S08, the reference welding position can be corrected based on the inclination, and the subsequent steps can be performed in the same manner as described above. Three circular openings W24 can also be handled in the same way as the three openings W22.

[0070] Furthermore, for the two circular openings W23, in step S02, the position data for the nearby rectangular opening W21 is processed so that the reference welding positions of the stud bolts B lined up on the outside of the opening W23 are also included. Therefore, the reference welding positions of the stud bolts B lined up on the outside of the opening W23 are set based on their positions relative to the center position of the opening W22. As a result, in step S08, the reference welding positions of the stud bolts B lined up on the outside of the opening W23 can be corrected together with the reference welding positions of the stud bolts B in the nearby opening W21, and the subsequent steps can be carried out in the same manner as described above.

[0071] In the above embodiment, the stud bolt B is used as the workpiece to be welded, but this is not limitative and the workpiece to be welded may be another shaft-shaped body or a structure having a shape other than a shaft-shaped body.

[0072] Furthermore, the number of workpieces W placed on the carriage 5 of the welding device 1 is not limited to two, but may be one, or three or more.

[0073] The shape of the opening W2 can be changed in various ways, such as to a polygon other than a circle or a rectangle, or to an ellipse.

[0074] Furthermore, the inclination of the opening W2 used in step S08 may be the inclination calculated based on the overall image data of the workpiece W in step S05, instead of the inclination calculated by the position specifying unit 75 as described above.

[0075] Furthermore, although the position data of the workpiece W is calculated from the graphic data by the graphic data conversion unit 72, the position data may be calculated by a device other than the welding device 1 and stored in the memory unit 76 via the input unit 56. [Explanation of symbols]

[0076] 1: Welding equipment 20: Welded section 40: Moving part 50: Aperture imaging unit 75:Location specifying section 76: Storage section 77: Movement control unit B: Stud bolt (welding object) W: Work W1: Top surface (welding surface) W2: Opening W3: Formation edge

Claims

1. 1. A welding apparatus for welding a workpiece to a welding surface where an opening is formed, a welding portion that holds the workpiece and welds it to the welding surface; a moving unit that moves the welding portion and the work-piece held by the welding portion to a welding position; an aperture imaging unit that images an edge of the aperture; a position specifying unit that specifies the welding position of the work-piece based on the aperture imaging data output from the aperture imaging unit; a movement control unit that controls movement of the moving unit based on the welding position identified by the position identifying unit.

2. a storage unit for storing position data including a reference welding position of the work-piece; The welding device according to claim 1 , wherein the position specifying unit calculates a corrected welding position by correcting the position data in accordance with the aperture image data, and specifies the corrected welding position as the welding position.

3. the position data further includes a center position of the opening, and the reference welding position is set based on a relative position with respect to the center position; 3. The welding device according to claim 2, wherein the position identifying unit calculates a center position of the opening based on the opening image data, and identifies the welding position based on a comparison between the calculated center position and the center position of the position data.

4. 3. The welding device according to claim 2, wherein the reference welding position is set in a position offset by a predetermined width from the opening in accordance with the position data.

5. 5. The welding device according to claim 1, wherein the aperture image capturing unit is provided so as to be movable together with the welding unit by the moving unit.

Images