Flexible robot welding system for middle rotary displacement pipe fitting

Abstract

Disclosed in the present invention is a flexible robot welding system for a middle rotary displacement pipe fitting. The flexible robot welding system comprises a clamp-type positioner and two welding systems located on two sides of the clamp-type positioner, wherein the clamp-type positioner comprises a driving wheel mechanism for driving pipe fitting to rotate and displace, and a clamp mechanism for pressing the pipe fitting; the clamp mechanism comprises a pressing wheel in contact with the pipe fitting, and a pressing-wheel driving device for driving the pressing wheel to ascend and descend, the pressing wheel rotating along with rotation of the pipe fitting and pressing the pipe fitting; the two welding systems are respectively located at two ends of the pipe fitting, and each welding system comprises a welding robot and an end pressing mechanism; and the end pressing mechanism comprises a pressing first roller in contact with the pipe fitting, and a roller driving device for driving the pressing first roller to ascend and descend, the pressing first roller rotating along with rotation of the pipe fitting and pressing the pipe fitting. The middle part and the two ends of the pipe fitting are pressed at the same time by means of the clamp-type positioner and the end pressing mechanism, such that straightness correction of the pipe fitting is achieved, thereby guaranteeing the welding quality.

Description

A flexible robot welding system for central rotation and position-changing pipe fittings Technical Field

[0001] The present invention relates to the welding production of pipe fittings for shipbuilding, chemical industry, aerospace and the like, and in particular to a flexible robot welding system for centrally rotating and position-shifting pipe fittings. Background Art

[0002] In the field of automated pipe fitting production in China, most pipe fitting welding uses end-to-end rotation and displacement, which cannot meet the automation requirements of four robots performing simultaneous welding. The main problems are: 1. The end-to-end rotation and displacement welding method interferes with the robot welding gun posture for simultaneous welding of the inner and outer circumferential seams; 2. Domestic pipe fittings generally suffer from poor straightness, resulting in large jitter during welding; 3. The treatment of the slipping problem during the rotation and displacement process is not ideal. 4. Most pipe fitting welding methods use a combination of a dedicated welding machine and a welding robot, which cannot fully utilize the development trend of flexible welding robots.

[0003] Summary of the Invention

[0004] Purpose of the invention: In order to solve the above problems, the present invention provides a flexible robot welding system for central rotation displacement pipe fittings, which improves the automation level of pipe fitting production and processing and the welding quality.

[0005] Technical solution: In order to solve the above problems, the present invention adopts a flexible robot welding system for central rotational positionable pipe fittings, including a clamp-type positioner and two welding systems located on both sides of the clamp-type positioner, the clamp-type positioner including a driving wheel mechanism for driving the pipe fitting to rotate and position and a clamp mechanism for clamping the pipe fitting, the clamp mechanism including a pressing wheel in contact with the pipe fitting and a pressing wheel driving device for driving the pressing wheel to rise and fall, the pressing wheel realizes the compression of the pipe fitting and rotates with the rotation of the pipe fitting; the two welding systems are respectively located at both ends of the pipe fitting, the welding system including a welding robot and an end clamping mechanism, the end clamping mechanism including a first clamping roller in contact with the pipe fitting and a roller driving device for driving the first clamping roller to rise and fall, the first clamping roller realizes the compression of the pipe fitting and rotates with the rotation of the pipe fitting.

[0006] Furthermore, the rotating shaft of the pressure wheel is fixedly connected to the input rotating shaft of the encoder, and the encoder is used to detect the actual rotation arc length of the pipe.

[0007] Furthermore, the welding system also includes a pipe runout detection mechanism, which includes a distance sensor for detecting radial runout during the rotation and displacement of the pipe.

[0008] Furthermore, the pressure wheel driving device includes a pressure clamp cylinder, the pressure wheel is fixed to the end of the pressure clamp cylinder through a bracket, and the pressure clamp cylinder is fixed to the end of the movable cylinder through a mounting base. When the pipe loading is completed, the movable cylinder drives the pressure clamp cylinder to rise to the highest point of the stroke, and the pressure clamp cylinder drives the bracket to rotate to rotate the pressure wheel to a working state above the pipe fitting. The movable cylinder drives the pressure clamp cylinder to move downward so that the pressure wheel presses the pipe fitting. When the pipe welding is completed and the material is unloaded, the pressure clamp cylinder drives the bracket to rotate in the opposite direction and reset, and the movable cylinder drives the pressure clamp cylinder to descend to the lowest point.

[0009] Furthermore, transfer tracks are set on both sides of the clamp-type positioner, and the transfer tracks are located between the clamp-type positioner and the welding system. The extension direction of the transfer tracks is perpendicular to the extension direction of the pipe fittings. Transfer trolleys are set on the transfer tracks on both sides of the clamp-type positioner, and a lifting platform is set on the upper end of the transfer trolley. The pipe fittings are placed on the lifting platform of the transfer trolley. The transfer trolley is used to transport the pipe fittings to the clamp-type positioner and transport them away from the clamp-type positioner, thereby realizing automatic loading and unloading of the pipe fittings.

[0010] Furthermore, the clamp-type positioner also includes a pipe grounding mechanism, which includes a central grounding copper block disposed at the bottom of the pipe and a central cylinder that drives the central grounding copper block up and down. The central cylinder drives the central grounding copper block to rise and press into contact with the pipe surface to achieve welding grounding. The welding system includes a roller grounding mechanism and a flange grounding mechanism. The roller grounding mechanism includes a welding ground wire connected to a first roller. The flange grounding mechanism includes a flange grounding copper block disposed under the end of the pipe and a flange cylinder that drives the flange grounding copper block up and down. The flange cylinder drives the flange grounding copper block to rise and press into contact with the pipe surface to achieve welding grounding. The upper surfaces of the central grounding copper block and the flange grounding copper block have an arc-shaped structure that matches the contact surface of the pipe.

[0011] Furthermore, the welding system includes a roller lifting mechanism for supporting the end of the pipe, the roller lifting mechanism includes a second roller and a third roller located in the same plane, a bracket for mounting the second roller and the third roller, and a roller cylinder for driving the bracket to move. After the pipe is loaded, the roller cylinder drives the bracket to rise, and the pipe contacts the second roller and the third roller. The welding system also includes a limiting mechanism (78) for limiting the roller lifting mechanism, the limiting mechanism includes a limiting cylinder, and the output end of the limiting cylinder extends to limit the movement of the bracket.

[0012] Furthermore, the welding system also includes a robot track and a slide that slides along the robot track. The extension direction of the robot track is parallel to the extension direction of the pipe. The welding robot and the end clamping mechanism are both arranged on the slide. The slide slides freely on the robot track to adapt to the welding of pipes of different lengths.

[0013] Beneficial effects: Compared with the prior art, the significant advantage of the present invention is that the middle and both ends of the pipe fittings are simultaneously clamped by a clamp-type positioner and an end clamping mechanism to achieve straightness correction of the pipe fittings and ensure welding quality. The pipe fitting runout detection mechanism detects the radial runout of the pipe fitting in real time during the rotational displacement process and feeds back to the control system. The control system adjusts the welding posture of the four welding robots in real time to ensure welding quality. In order to prevent the pipe fitting from slipping during the rotational displacement process, the arc length detection mechanism automatically detects the actual rotational displacement arc length of the pipe fitting and feeds back to the control system. The control system adjusts the welding speed of the four welding robots in real time to ensure welding quality. In order to solve the problem of poor grounding effect due to the presence of floating rust on the surface of the pipe fitting and the flange surface, the present invention adopts a grounding scheme of grounding the flanges at both ends, grounding the two ends of the pipe fitting and grounding the middle of the pipe fitting to achieve reliable and stable grounding. According to the welding tasks of pipe fittings of different lengths, the left welding system and the right welding system automatically run to the specified position on the track to achieve flexible welding of pipe fittings of different lengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG1 is a schematic diagram of the three-dimensional structure of the flexible robot welding system of the present invention.

[0015] FIG2 is a top view of the flexible robot welding system of the present invention.

[0016] FIG3 is a schematic diagram of the three-dimensional structure of the pressure roller grounding mechanism of the present invention.

[0017] FIG4 is a schematic diagram of the three-dimensional structure of the welding robot in the present invention.

[0018] FIG5 is a schematic diagram of the three-dimensional structure of the driven wheel mechanism in the present invention.

[0019] FIG6 is a schematic diagram of a partial three-dimensional structure of the driven wheel mechanism in the first direction of the present invention.

[0020] FIG7 is a schematic diagram of a partial three-dimensional structure of the driven wheel mechanism in the second direction of the present invention.

[0021] FIG8 is a schematic diagram of a partial three-dimensional structure of the driven wheel mechanism in the third direction of the present invention

[0022] FIG9 is a schematic diagram of the three-dimensional structure of the pipe wrench positioner of the present invention.

[0023] FIG10 is a schematic diagram of the three-dimensional structure of the pipe clamp positioner of the present invention with the cover plate removed.

[0024] FIG11 is a three-dimensional structural diagram of the clamping mechanism and arc length detection mechanism of the pipe clamp positioner of the present invention.

[0025] FIG12 is a schematic diagram of the three-dimensional structure of the pipe grounding mechanism of the pipe clamp positioner of the present invention.

[0026] FIG13 is a schematic diagram of the three-dimensional structure of the driving wheel mechanism of the pipe wrench positioner of the present invention. DETAILED DESCRIPTION

[0027] As shown in Figures 1 and 2, in this embodiment, a flexible robot welding system for a central rotationally displaced pipe fitting includes a left welding system 2, a right welding system 1, a clamp-type positioner 3, an RGV transfer system 4 and a control system 5. The left welding system 2 realizes the compression and driven displacement of the left end of the pipe fitting 6, the grounding of the flange 26, the grounding of the pipe fitting 6, the welding of the inner and outer ring seams, and the flexible adjustment according to the length of the pipe fitting 6, etc. The right welding system 1 realizes the compression and driven displacement of the right end of the pipe fitting 6, the welding grounding of the flange 110, the grounding of the pipe fitting 6, the welding of the inner and outer ring seams, and the flexible adjustment according to the length of the pipe fitting 6, etc. The clamp-type positioner 3 completes the central rotation displacement of the pipe fitting 6, the welding grounding of the pipe fitting 6, the actual rotation arc length measurement feedback, etc. The RGV transfer vehicle 4 is used for automatic loading and unloading of the pipe fitting 6, and the control cabinet 5 controls the above equipment to execute in an orderly manner according to the production process. In this embodiment, the functions of automatic loading and unloading of the pipe fitting 6, central rotation and displacement, pipe clamping correction, grounding of flanges at both ends, actual rotation arc length measurement system, pipe vibration detection and three-point straight pipe grounding, and pipe length adaptation are realized, and four welding robots are used to simultaneously weld the pipe fitting 6 (diameter range 48mm-219mm and length range 0.6m-4m) with the inner and outer ring welds of the flanges 26 and flange 110 at both ends, thereby improving the automation level and welding quality of the production and processing of the pipe fitting 6.

[0028] As shown in Figure 2, the right welding system 1 includes a robot track 21, a slide 106, a welding robot 19, a welding robot 14, a driven wheel mechanism 13, a pressure roller grounding mechanism 28, a gun cleaning and wire shearing machine 29, a robot control cabinet 31, a robot controller 32, and welding power supplies 16 and 17. The slide 106 includes a slide plate 20, a connecting rod 30, a slide plate 18, and a mounting plate 15. Slide plates 20 and 18 are connected by two connecting rods 30, and the mounting plate 15 is connected to the slide plate 18. The slide 106, driven by a servo motor, freely slides on the robot track 21 with a rack-and-pinion mechanism, enabling the welding of pipes 6 of varying lengths. The welding robot 19 is fixed to the slide plate 20 of the slide 106, while the welding robot 14, the driven wheel mechanism 13, the pressure roller grounding mechanism 28, the gun cleaning and wire shearing machine 29, and the welding power supplies 16 and 17 are fixed to the mounting plate 15 of the slide 106.

[0029] As shown in Figure 3, the pressure roller grounding mechanism 28 of the right welding system 1 includes a base 73, a pipe runout detection mechanism, and a roller grounding mechanism. The pipe runout detection mechanism includes a distance sensor 65, a bracket 66, and a cantilever bracket 67. The distance sensor 65 is mounted on the base 73 via the bracket 66 and the cantilever bracket 67. The base 73 is fixedly mounted on the slide 106. The distance sensor 65 detects the radial runout of the pipe 6 during rotation and displacement and provides feedback to the control system 5. The control system 5 adjusts the welding gun posture of the welding robot 19 and the welding robot 14 in real time to ensure welding quality. The roller grounding mechanism includes a cylinder 72, a slider 71, a bracket 70, and a roller 68. The roller 68 is assembled with the bracket 70 by installing a bearing and an insulating ring inside the bracket 70 and installing end caps on both sides of the bracket 70. The roller 68 is connected to the welding ground wire to ensure welding grounding effect. The bracket 70 is fixed on the slider 71 of the cylinder 72. When the slider 71 moves downward, the roller 68 is pressed down to execute the action, and when the slider 71 moves upward, the roller 68 is pressed down to release the action.

[0030] As shown in Figure 4, the welding robot 14 of the right welding system 1 is connected to the mounting plate 15 via a base 62, and the supporting wire feeder 63 is connected to the base 62 via a bracket 64. The supporting wire feeder of the welding robot 19 is installed on the robot body.

[0031] As shown in Figures 5 to 8, the driven wheel mechanism 13 of the right welding system 1 is used to support the pipe fitting 6 when the pipe clamp positioner drives it to rotate. The driven wheel mechanism 13 includes a frame 69, a roller lifting mechanism 74, a limiting mechanism 78, and a flange grounding mechanism 75. The frame 69 includes a mounting base 79 and a cover plate 81, which is fixed to the mounting base 79. The roller lifting mechanism 74, the limiting mechanism 78, and the flange grounding mechanism 75 are all mounted on the frame 69. The roller lifting mechanism 74 includes a second roller 84, a third roller 86, a bracket 77, a cover plate 80, an end cap 82, an end cap 87, a roller cylinder 94, a mounting base 91, a round block 88, a connecting block 85, a guide rail 93, a guide rail 100, a slider 98, a slider 103, a slider 92, and a slider 104. The second roller 84 is fixed to the bracket 77 via the end cap 82, and the third roller 86 is fixed to the bracket 77 via the end cap 87. The left side of bracket 77 is connected to guide rail 93 via sliders 92 and 104. Guide rail 93 is fixed to mounting base 79. Similarly, the right side of bracket 77 is connected to guide rail 100 via sliders 98 and 103. Guide rail 100 is mounted on mounting base 79. Cover plate 80 is mounted on bracket 77 for protection. Roller cylinder 94 is connected to mounting base 79 via mounting base 91. The end of piston rod 90 is connected to round block 88. Connecting block 85 is fixed to mounting base 79. Round block 88 fits within the T-slot of connecting block 85. When piston rod 90 of roller cylinder 94 moves up and down, it drives the second roller 84 and third roller 86 on bracket 74 to rise and fall.

[0032] As shown in Figure 7, the limiting mechanism 78 includes a limiting cylinder 76, a guide wheel 96, a limiting plate 95 and a limiting plate 89. The limiting cylinder 76 is fixed on the mounting seat 79, the guide wheel 96 is installed on the piston rod 97 of the limiting cylinder 76, and the limiting plate 95 and the limiting plate 89 are installed on the bracket 77. When the second roller 84 and the third roller 86 complete the rising action, the limiting cylinder 76 drives the piston rod 97 to extend to limit and lock the limiting plate 95 of the roller lifting mechanism 74, ensuring that the roller lifting mechanism 74 is always in an ascending state. When the second roller 84 and the third roller 86 need to descend, the limiting cylinder 76 drives the piston rod 97 to retract, releasing the limit on the limiting plate 95 of the roller lifting mechanism 74. The flange grounding mechanism 75 includes a flange cylinder 99, a grounding copper block 101 and a grounding wire connection seat 102. The grounding wire connection seat 102 is fixed under the grounding copper block 101. The grounding copper block 101 is connected to the piston rod of the flange cylinder 99. The flange cylinder 99 is fixed on the mounting seat 91. The upper surface of the grounding copper block 101 is designed with an arc structure to increase the contact surface with the pipe fitting. The flange cylinder 99 drives the grounding copper block 101 to rise and press it into contact with the surface of the pipe fitting to achieve welding grounding. When the pipe fitting 6 is welded and needs to be unloaded, the flange cylinder 99 drives the grounding copper block 101 to drop to the lowest point to avoid the unloading action of the pipe fitting 6.

[0033] As shown in Figures 9 to 13, the clamp-type positioner 3 includes a frame 39, a drive wheel mechanism 34, a roller mechanism 36, a clamp mechanism 38, an arc length detection mechanism 37, and a pipe grounding mechanism 35. The frame 39 includes a base 42, a mounting seat 41, a cover plate 43, a cover plate 44, and a cover plate 45. The mounting seat 41 is fixed above the base 42, the cover plate 45 is fixed above the mounting seat 41, and the cover plates 43 and 44 are fixed to the sides of the base 42. The drive wheel mechanism 34 mainly drives the pipe 6 to rotate and shift, and includes rollers 57, rollers 59, a drive motor 60, and a reducer 58. The reducer 58 is installed at the output end of the drive motor 60, and the rollers 57 and rollers 59 are installed at the output end of the reducer 58. The side of the reducer 58 is fixed to the mounting seat 41. The roller mechanism 36 cooperates with the driving wheel mechanism 34 to perform center positioning and driven rolling of the pipe 6, and includes a roller 61, a roller 107 and an end cover 40. The roller 61 and the roller 107 are fixed to the mounting seat 41 through two end covers 40.

[0034] The pressing mechanism 38 includes a mobile cylinder 47, a mounting base 46, a pressing cylinder 48, a bracket 50 and a pressing wheel 49. The pressing wheel 49 is fixed to the end of the pressing cylinder 48 through the bracket 50. The pressing cylinder 48 is fixed to the end of the piston rod of the mobile cylinder 47 through the mounting base 46. The mobile cylinder 47 is fixed on the base 42. When the pipe fitting 6 is loaded, the mobile cylinder 47 drives the pressing cylinder 48 to rise to the highest point of the stroke, and the pressing cylinder 48 drives the front end pressing clamp to rotate to the working state. The mobile cylinder 47 drives the pressing cylinder 48 to move downward to press the pipe fitting 6. When the pipe fitting 6 is welded and needs to be unloaded, the pressing cylinder 48 drives the front end pressing clamp to rotate in the opposite direction and reset. The mobile cylinder 47 drives the pressing cylinder 48 to drop to the lowest point. At this time, the highest point of the pressing cylinder 48 structure is lower than the upper surface of the cover plate 45 to avoid the unloading action of the pipe fitting 6.

[0035] The arc length detection mechanism 37 includes an encoder 52, a mounting seat 51 and a coupling. The encoder 52 is installed on the mounting seat 51. The input rotating shaft of the encoder 52 is connected to the rotating shaft of the pressure wheel 49 through the coupling installed in the mounting seat 51, so as to detect the actual rotation arc length of the pipe fitting 6 in real time and solve the problem of possible slipping of the pipe fitting. The pipe grounding mechanism 35 includes a middle cylinder 54, a base plate 55, a connecting plate 56, a grounding copper block 108 and a grounding wire connection seat 53. The middle cylinder 54 is fixed on the base plate 55, and the base plate 55 is fixed on the mounting seat 41 through the connecting plate 56. The grounding wire connection seat 53 is fixed below the grounding copper block 108. The grounding copper block 108 is fixed at the end of the piston rod of the middle cylinder 54. The upper surface of the grounding copper block 108 is designed with an arc structure to increase the contact surface with the pipe. When the pipe 6 is loaded, the middle cylinder 54 drives the grounding copper block 108 to rise and press it into contact with the surface of the pipe to achieve welding grounding. When the pipe 6 is welded and needs to be unloaded, the middle cylinder 54 drives the grounding copper block 108 to drop to the lowest point. At this time, the highest point of the pipe grounding mechanism 35 structure is lower than the upper surface of the cover plate 45 to avoid the unloading action of the pipe 6.

[0036] As shown in Figure 2, the left welding system 2 includes a robot track 2-1, a slide 105, a welding robot 2-2, a welding robot 8, a driven wheel mechanism 9, a pressure wheel grounding mechanism 107, a gun cleaning and wire shearing machine 24, a robot control cabinet 22, a robot control 23, a welding power supply 2-5, and a welding power supply 2-6. Slide 105 is similar in structure to slide 106 and includes a slide 2-3, a connecting rod 2-4, a slide 109, and a mounting plate 7. Slides 2-3 and 109 are connected by two connecting rods 2-4, and the mounting plate 7 is connected to slide 109. The welding robot 8 and the welding robot 14 have the same structure, and the driven wheel mechanism 9 and the driven wheel mechanism 13 have the same structure, which will not be repeated here. The pressure wheel grounding mechanism 107 and the pressure wheel grounding mechanism 28 are structurally symmetrical and operate in the same manner, which will not be repeated here.

[0037] As shown in Figure 2, the RGV transfer system 4 includes a transfer track 25, a transfer track 27, an RGV trolley 10 and an RGV trolley 11. The RGV trolley 10 runs on the transfer track 25, and the RGV trolley 11 runs on the transfer track 27. A lifting platform is set on the upper end of the RGV trolley 10 and the RGV trolley 11, and the pipe fittings 6 are placed on the lifting platform of the RGV trolley. The RGV trolley is used to transport the pipe fittings to the clamp-type positioner and transport them away from the clamp-type positioner. The synchronous operation of the RGV trolley 10 and the RGV trolley 11 can realize automatic loading and unloading of the pipe fittings 6 on the clamp-type positioner 3, the driven wheel mechanism 9 and the driven wheel mechanism 13.

[0038] 1 to 13 , the basic execution process of a flexible robot welding system for central rotation and position-shifting pipe fittings is as follows:

[0039] The first step is loading preparation. The roller lifting mechanism of the driven wheel mechanism 13 moves upward to its highest point, and the roller lifting mechanism of the driven wheel mechanism 9 moves upward to its highest point. The clamping mechanism 38, arc length detection mechanism 37, and pipe grounding mechanism 35 of the clamping positioner 3 move to their lowest point. The control system 5 automatically determines the length of the pipe 6 for the next production task. The left welding system 2 and the right welding system 1 automatically move to the designated position on the robot track, ensuring that the flange grounding mechanisms of the driven wheel mechanism 13 and the flange grounding mechanisms of the driven wheel mechanism 9 are directly below the flanges at both ends of the pipe 6.

[0040] The second step is loading. The RGV transfer system 4 automatically transfers the pipe 6 to the top of the clamp positioner 3, the driven wheel mechanism 13 and the driven wheel mechanism 9 and lowers it for placement.

[0041] The third step is compaction correction. The roller grounding mechanism of the pressing wheel grounding mechanism 28 and the roller grounding mechanism of the pressing wheel grounding mechanism 107 automatically move downward and compact the pipe 6. The pressing clamp mechanism 38 of the pressing clamp positioner 3 automatically rises to the highest point and then opens the front end pressing clamp and automatically descends to compact the pipe 6, thereby achieving straightness correction and compaction of the pipe 6.

[0042] In the fourth step, the straight pipe and flange are grounded. The pipe grounding mechanism 35 of the pressure clamp positioner 3 moves upward to contact the pipe 6, and together with the roller grounding of the pressure wheel grounding mechanism 28 and the pressure wheel grounding mechanism 107, the pipe 6 is grounded at three locations. The flange grounding mechanism of the driven wheel mechanism 13 moves upward to contact the flange 110, and the flange grounding mechanism of the driven wheel mechanism 9 contacts the flange 26, completing the grounding of the flanges at both ends.

[0043] Step 5: Synchronous welding of the inner and outer annular seams. The drive wheel mechanism 34 of the pressure clamp positioner 3 rotates and positions the pipe 6. Welding robots 2-2, 8, 19, and 14 simultaneously weld the flanges at both ends of the pipe 6. Based on feedback from the arc length detection mechanism 37 of the pressure clamp positioner 3 and the radial runout of the pipe during rotation and position, as measured by the pipe runout detection mechanisms 28 and 107, the control system 5 adjusts the welding postures of the four welding robots in real time to ensure welding quality.

[0044] Step 6: Prepare for blanking. After the current welding task is completed, the driving wheel mechanism 34 of the clamp positioner 3 stops rotating, and the clamp mechanism 38 of the clamp positioner 3 resets the front clamp and descends to the lowest point. The roller grounding mechanisms of the clamp grounding mechanism 28 and the clamp grounding mechanism 107 move upward and reset; the pipe grounding mechanism 35 of the clamp positioner 3 moves downward and reset; and the flange grounding mechanisms of the driven wheel mechanism 13 and the driven wheel mechanism 9 both move downward and reset.

[0045] The seventh step is unloading. The RGV transfer system 4 automatically rises to the bottom of the pipe fitting 6, lifts the pipe fitting 6 to the highest point and transfers it to the next process.

Claims

1. A flexible robot welding system for a middle-rotating and positioning pipe fitting, Characterized in that, It includes a clamping-type positioner (3) and two welding systems located on both sides of the clamping-type positioner (3). The clamping-type positioner (3) includes a driving wheel mechanism (34) for driving the rotation and positioning of the pipe fitting (6) and a clamping mechanism (38) for clamping the pipe fitting (6). The clamping mechanism (38) includes a pressing wheel (49) in contact with the pipe fitting (6) and a pressing wheel driving device for driving the lifting of the pressing wheel (49). The pressing wheel (49) rotates while pressing the pipe fitting (6) and rotates with the rotation of the pipe fitting (6); the two welding systems are respectively located at both ends of the pipe fitting (6), and the welding system includes a welding robot (2, 8, 14, 19) and an end clamping mechanism. The end clamping mechanism includes a first pressing roller (68) in contact with the pipe fitting (6) and a roller driving device for driving the lifting of the first pressing roller (68). The first pressing roller (68) rotates while pressing the pipe fitting (6) and rotates with the rotation of the pipe fitting (6).

2. The flexible robot welding system according to claim 1, Characterized in that, The rotation axis of the pressing wheel (49) is fixedly connected to the input rotation axis of the encoder (52), and the encoder is used to detect the actual rotation arc length of the pipe fitting (6).

3. The flexible robot welding system according to claim 1, Characterized in that, The welding system further includes a pipe fitting runout detection mechanism, and the pipe fitting runout detection mechanism includes a ranging sensor (65), and the ranging sensor (65) is used to detect the radial runout during the rotation and positioning of the pipe fitting (6).

4. The flexible robot welding system according to claim 1, Characterized in that, The pressing wheel driving device includes a clamping cylinder (48), the pressing wheel (49) is fixed at the end of the clamping cylinder (48) through a bracket (50), and the clamping cylinder (48) is fixed at the end of the moving cylinder (47) through a mounting seat (46). After the pipe fitting (6) is loaded, the moving cylinder (47) drives the clamping cylinder (48) to rise to the highest point of the stroke, and the clamping cylinder (48) drives the bracket to rotate to rotate the pressing wheel (49) to the working state above the pipe fitting. The moving cylinder (47) drives the clamping cylinder (48) to move downward so that the pressing wheel (49) clamps the pipe fitting (6). When the pipe fitting (6) is welded and unloaded, the clamping cylinder (48) drives the bracket (50) to rotate in the reverse direction to reset, and the moving cylinder (47) drives the clamping cylinder (48) to descend to the lowest point.

5. The flexible robot welding system according to claim 1, Characterized in that, On both sides of the clamping type positioner (3), transfer tracks (25, 27) are provided. The transfer tracks (25, 27) are located between the clamping type positioner (3) and the welding system. The extending direction of the transfer tracks (25, 27) is perpendicular to the extending direction of the pipe fitting. Transfer carts (10, 11) are provided on both sides of the clamping type positioner (3). An elevating platform is arranged at the upper end of the transfer carts (10, 11). The pipe fitting is placed on the elevating platform of the transfer cart. The transfer cart is used to transport the pipe fitting to the clamping type positioner (3) and transport it away from the clamping type positioner (3), realizing automatic loading and unloading of the pipe fitting.

6. The flexible robot welding system according to claim 1, characterized in that, the clamping type positioner (3) further includes a pipe fitting grounding mechanism (35). The pipe fitting grounding mechanism (35) includes a middle grounding copper block (108) arranged at the bottom of the pipe fitting (6) and a middle air cylinder (54) for driving the middle grounding copper block (108) to move up and down. The middle air cylinder (54) drives the middle grounding copper block (108) to rise and press against the surface of the pipe fitting to achieve welding grounding; the welding system includes a roller grounding mechanism and a flange grounding mechanism (75). The roller grounding mechanism includes a welding ground wire connected to the first roller (68). The flange grounding mechanism (75) includes a flange grounding copper block (101) arranged under the end of the pipe fitting (6) and a flange air cylinder (99) for driving the flange grounding copper block (101) to move up and down. The flange air cylinder (99) drives the flange grounding copper block (101) to rise and press against the surface of the pipe fitting to achieve welding grounding.

7. The flexible robot welding system according to claim 6, characterized in that, the upper surfaces of the middle grounding copper block (108) and the flange grounding copper block (101) are arc-shaped structures matching the contact surface of the pipe fitting.

8. The flexible robot welding system according to claim 6, characterized in that, the welding system includes a roller lifting mechanism (74) for supporting the end of the pipe fitting. The roller lifting mechanism (74) includes a second roller (84) and a third roller (86) located in the same plane, a bracket (77) for installing the second roller (84) and the third roller (86), and a roller air cylinder (94) for driving the bracket (77) to move. After the pipe fitting is loaded, the roller air cylinder (94) drives the bracket (77) to rise, and the pipe fitting contacts the second roller (84) and the third roller (86).

9. The flexible robot welding system according to claim 8, characterized in that, the welding system further includes a limiting mechanism (78) for limiting the roller lifting mechanism (74). The limiting mechanism (78) includes a limiting air cylinder (76). The output end of the limiting air cylinder (76) extends to limit the movement of the bracket (77).

10. The flexible robot welding system according to claim 1, characterized in that, The welding system further includes robot tracks (1, 21) and sliders (105, 106) that slide along the robot tracks (1, 21). The extending direction of the robot tracks (1, 21) is parallel to the extending direction of the pipe fitting (6). The welding robots (2, 8, 14, 19) and the end pressing mechanism are both arranged on the sliders (105, 106). The sliders (105, 106) freely slide on the robot tracks (1, 21) to adapt to the welding of pipe fittings (6) with different lengths.

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