Automatic welding device for inner circular seam of large steel pipe

Abstract

The invention discloses an automatic welding device for an inner circular seam of a large steel pipe, which relates to the technical field of pipeline welding and comprises a positioning and centering mechanism, a seam adjusting and positioning mechanism and a welding executing mechanism, a first positioning telescopic arm and a second positioning telescopic arm, which are distributed in a cross shape, of the positioning centering mechanism and the joint adjusting positioning mechanism extend outwards at the same time, the inner walls of two adjacent steel pipes can be automatically clamped and centered for positioning, and the welding execution mechanism adopts a multi-axis mechanical arm to be matched with a visual sensor to accurately position the position of a welding seam. The welding gun is driven to be aligned with the position of the inner circular seam, the annular rotating base rotates at a constant speed, one welding gun is driven to conduct 360-degree automatic welding along the inner circular seam, or the multiple welding guns are driven to rotate by a certain angle along the inner circular seam to jointly complete 360-degree welding work. The device is arranged in the steel pipe, rapid and high-precision centering positioning is achieved through multi-point synchronous supporting, the device is matched with a welding executing mechanism to execute automatic welding work of the inner circular seam of the steel pipe, and the construction efficiency and the welding quality can be improved.

Description

Technical Field

[0001] This invention relates to the field of pipeline welding technology, and in particular to an automatic welding device for the inner circumferential seam of large steel pipes. Background Technology

[0002] In the fabrication of large steel structures or pipeline construction, it is often necessary to butt weld multiple thick-walled steel pipe sections together. Due to the large diameter and heavy weight of each pipe section, current technologies require manual centering and operation using foot-operated equipment during the welding process. Manual centering and welding are not only inefficient and labor-intensive, but also make it difficult to ensure the coaxiality and uniformity of the weld seam. This results in complex installation, limited operating space, and unstable weld quality, potentially leading to welding deformation and misalignment, which affect the overall structural strength and sealing performance. Therefore, there is an urgent need for an automated device capable of automatic centering, precise positioning, and stable welding to improve construction efficiency and welding quality. Summary of the Invention

[0003] This invention provides an automatic welding device for the inner circumferential seam of large steel pipes. It adopts multi-point synchronous support to achieve rapid and high-precision centering and positioning. It works in conjunction with the welding actuator to perform automatic welding of the inner circumferential seam of the steel pipe, which can improve construction efficiency and welding quality.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] An automatic welding device for the inner circumferential seam of a large steel pipe is installed inside the steel pipe. It includes a positioning and centering mechanism, a joint adjustment and positioning mechanism, and a welding execution mechanism.

[0006] The positioning and centering mechanism includes a first main frame, a plurality of first positioning telescopic arms, a plurality of magnetic fixing seats, and a plurality of support arms. A walking mechanism is provided at the bottom of the first main frame. A first keel positioning shaft is horizontally arranged at the center of the first main frame. The keel positioning shaft is fixedly connected to the periphery of the first main frame. Two cross-shaped connecting seats are spaced apart on the first keel positioning shaft, distributed on both sides of the first main frame. The cross-shaped end of each cross-shaped connecting seat is fixedly connected to one end of a first positioning telescopic arm, and the other end of each first positioning telescopic arm is fixedly connected to a magnetic fixing seat. A support arm is provided between each pair of adjacent first positioning telescopic arms, with both ends of the support arm fixedly connected to the middle of a corresponding first positioning telescopic arm. The first keel positioning shaft is also fixedly connected to the middle of each first positioning telescopic arm via a support arm. The plurality of first positioning telescopic arms simultaneously extend outwards to allow the magnetic fixing seats to abut against the inner wall of the steel pipe.

[0007] The seam adjustment and positioning mechanism includes a second main frame, several second positioning telescopic arms, several telescopic adjustment arms, several magnetic fixing seats, and several support arms; a walking mechanism is provided at the bottom of the second main frame; a second keel positioning shaft is horizontally arranged at the center of the second main frame, and the second keel positioning shaft is fixedly connected to the second main frame around its periphery. Two cross-shaped connecting seats are also spaced apart on the second keel positioning shaft, and the two cross-shaped connecting seats are distributed on both sides of the second main frame. The cross-shaped end of each cross-shaped connecting seat is fixedly connected to one end of a second positioning telescopic arm, and the other end of each second positioning telescopic arm is fixedly connected to a magnetic fixing seat. A support arm is provided between each pair of adjacent second positioning telescopic arms, and the two ends of the support arm are respectively fixedly connected to the middle of the corresponding second positioning telescopic arm; the second keel positioning shaft is also fixedly connected to the middle of each second positioning telescopic arm through a support arm; the second main frame is located on one side of the first main frame; one end of the second keel positioning shaft is slidably connected to one end of the first keel positioning shaft through a shaft hole; the positions of adjacent first positioning telescopic arms and second positioning telescopic arms correspond one-to-one, and a first positioning telescopic arm and a second positioning telescopic arm corresponding to each other are connected by a telescopic adjustment arm;

[0008] The welding actuator is located between the first main frame and the second main frame. The welding actuator includes an annular fixed seat, an annular rotating seat, an internal gear ring, a drive gear, a rotary drive motor, a multi-axis robotic arm, a welding torch, and a vision sensor. The inner ring of the annular fixed seat is fixedly connected to the first keel positioning shaft. The annular rotating seat is rotatably connected to the outer ring of the annular fixed seat. The internal gear ring is coaxially fixed to one side of the annular rotating seat. The rotary drive motor is fixedly installed inside the outer ring of the annular fixed seat. The rotating shaft of the rotary drive motor is driven by the drive gear and the internal gear ring to drive the annular rotating seat to rotate along the annular fixed seat. Several welding machine mounting seats are distributed at equal angles on the other side of the annular rotating seat. Each welding machine mounting seat is fixedly connected to the annular rotating seat. Each welding torch is mounted on the welding machine mounting seat through a multi-axis robotic arm. Each multi-axis robotic arm is equipped with a vision sensor.

[0009] Furthermore, it also includes a welding construction base, which is used to horizontally place the steel pipe to be welded. The welding construction base includes a positioning base and several movable bases. The positioning base is provided with several sets of positioning wheels symmetrically distributed in an inverted figure-eight shape. The axle direction of each positioning wheel is parallel to the axis direction of the steel pipe, so that each positioning wheel is tangent to the outer peripheral wall of the steel pipe. Each movable base is provided with several sets of pulleys symmetrically distributed in an inverted figure-eight shape. The steel pipe slides horizontally through the pulleys. The distance from the axis of the steel pipe to the perpendicular foot of each positioning wheel or each pulley is equal.

[0010] Furthermore, the positioning base is equipped with a ratchet and a ratchet locking handle for each positioning wheel. The ratchet is coaxially fixed with the positioning wheel, and each ratchet locking handle is installed on one side of the outer circumference of a ratchet. Each ratchet locking handle extends and retracts along the positioning base to lock the corresponding ratchet.

[0011] Furthermore, the side of the magnetic fixing base that fits against the inner wall of the steel pipe is designed as a matching arc surface structure. The magnetic fixing base is provided with a plurality of mounting holes, and an electromagnet is fixedly connected between each mounting hole. The magnetic end of the electromagnet extends through the arc surface structure, and the outer contour of the magnetic end matches the arc surface structure.

[0012] Furthermore, a pressure sensor is provided between each of the first positioning telescopic arms and the corresponding magnetic fixing base, and between each of the second positioning telescopic arms and the corresponding magnetic fixing base.

[0013] Furthermore, a tension sensor is provided between each of the telescopic adjustment arms and the corresponding first positioning telescopic arm.

[0014] Furthermore, an infrared laser sensor is provided on the outer periphery of the annular rotating seat.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1) This invention is installed inside a steel pipe. The first and second positioning telescopic arms, arranged in a cross shape, extend outward simultaneously to automatically clamp the inner walls of two adjacent steel pipes and center them. The magnetic positioning seat improves the fixing effect between the first and second positioning telescopic arms and the inner wall of the steel pipe. Together with the telescopic adjustment arm, they simultaneously retract to pull the two adjacent steel pipes tightly together, maintaining the weld gap. The multi-axis robotic arm, in conjunction with a vision sensor, accurately positions the weld and drives the welding torch to align with the inner circumferential seam. The annular rotating seat rotates at a uniform speed, driving one welding torch to automatically weld along the inner circumferential seam 360° or driving multiple welding torches to rotate along the inner circumferential seam at a certain angle to complete the 360° welding work. This invention uses multi-point synchronous support to achieve fast and high-precision centering and positioning. Combined with the welding execution mechanism, it performs automatic welding of the inner circumferential seam of the steel pipe, which can improve construction efficiency and welding quality.

[0017] 2) The welding construction base can be placed horizontally on the steel pipe to be welded. The positioning base can fix one section of the steel pipe, and the movable base can be easily adjusted along the horizontal direction of the steel pipe. With the joint adjustment and positioning mechanism, the docking work of two adjacent sections of steel pipe can be completed quickly.

[0018] 3) The magnetic fixing seat is fixed to the inner wall of the steel pipe by electromagnet, and the pressure of the first positioning telescopic arm and the second positioning telescopic arm extending outward together fixes the steel pipe.

[0019] 4) Each first positioning telescopic arm and each second positioning telescopic arm are equipped with a pressure sensor, which can monitor the real-time support force when they extend outward to abut against the inner wall of the steel pipe, preventing excessive clamping that could cause deformation of the pipe wall.

[0020] 5) An infrared laser sensor is provided on the outer periphery of the annular rotary seat. During use, a cursor mark can be set at an appropriate distance on one side of the inner ring seam. The infrared laser sensor senses the position of the cursor mark and determines the relative position of the current annular rotary seat and the inner ring seam. At this position, the positioning and centering mechanism is controlled to support and fix the inner wall of the steel pipe to achieve initial positioning and avoid exceeding the working radius of the multi-axis robotic arm due to the positioning and centering mechanism being placed too far off. Attached Figure Description

[0021] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0022] Figure 1 This is a schematic diagram of the structure in the working state of the present invention;

[0023] Figure 2 This is a schematic diagram of the planar structure of one side of the welding actuator in this invention;

[0024] Figure 3 This is a schematic diagram of the planar structure of the other side of the welding actuator in this invention;

[0025] Figure 4 This is a schematic diagram of the structure in this invention where the steel pipe is placed on the welding construction base;

[0026] Figure 5 This is a schematic diagram of the structure in this invention where the steel pipe is placed on the positioning base;

[0027] Figure 6 This is a schematic diagram of the structure in this invention where the steel pipes are placed on the movable base;

[0028] Figure 7 This is a schematic diagram of the structure from a side view in the working state of the present invention;

[0029] Attached image labels:

[0030] 1-Steel pipe, 2-Automatic centering mechanism, 3-Joint adjustment and positioning mechanism, 4-Welding execution mechanism, 5-Inner circumferential joint, 6-Welding construction base, 21-First main frame, 22-First positioning telescopic arm, 23-Magnetic fixing seat, 24-Support arm, 211-Traveling mechanism, 212-First keel positioning shaft, 213-Cross connecting seat, 214-Reinforcing arm, 31-Second main frame, 32-Second positioning telescopic arm, 33-Telescopic adjustment arm, 312-Second keel positioning Shaft, 313-Cross connector, 41-Annular fixed seat, 42-Annular rotating seat, 43-Internal gear ring, 44-Drive gear, 45-Rotary drive motor, 46-Multi-axis robotic arm, 47-Welding torch, 48-Vision sensor, 411-Inner ring, 412-Outer ring, 413-Support rod, 421-Welding machine mounting base, 422-Infrared laser sensor, 61-Positioning base, 62-Modible base, 611-Positioning wheel, 612-Ratchet locking handle, 621-Pulley. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a central component. When a component is described as "connected to" another component, it can be directly connected to the other component or may have a central component. When a component is described as "set on" another component, it can be directly set on the other component or may have a central component. When a component is described as "set in the middle," it is not simply set in the exact center, as long as it is not set within the area defined by both ends being in the middle. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] Reference Figures 1 to 7 As shown, an automatic welding device for the inner circumferential seam of a large steel pipe is installed inside the steel pipe 1. It includes a positioning and centering mechanism 2, a joint adjustment and positioning mechanism 3, and a welding execution mechanism 4.

[0035] The positioning and centering mechanism 2 includes a first main frame 21, several first positioning telescopic arms 22, several magnetic fixing seats 23, and several support arms 24; the first positioning telescopic arms 22 are hydraulic cylinders; the bottom of the first main frame 21 is provided with a walking mechanism 211, which can be configured as a heavy-duty directional wheel; a first keel positioning shaft 212 is horizontally arranged at the center of the first main frame 21, and radially radiating reinforcing arms 214 are welded and fixed around the first keel positioning shaft 212. The other end of the reinforcing arm 214 is welded and fixed to the first main frame 21. Two cross connecting seats 213 are spaced apart on the first keel positioning shaft 212. The cross connecting seats 213 are welded and fixed to the first keel positioning shaft 212. The vertical line of the cross connecting seat 213 is aligned with the vertical bisector of the first main frame 21 to maintain the overall center of gravity in the center. Cross-shaped connectors 213 are distributed on both sides of the first main frame 21. Each cross-shaped connector 213 has a flange at its cross-shaped end. One end of each first positioning telescopic arm 22 is bolted to the corresponding flange, and the other end is bolted to a magnetic fixing seat 24. A support arm 24 is provided between each pair of adjacent first positioning telescopic arms 22, with both ends of the support arm 24 fixedly connected to the middle of a corresponding first positioning telescopic arm 22. The first keel positioning shaft 212 is also fixedly connected to the middle of each first positioning telescopic arm 22 via a support arm 24, which strengthens the first positioning telescopic arm 22. Several first positioning telescopic arms 22 extend outwards simultaneously to allow the magnetic fixing seat 24 to abut against the inner wall of the steel pipe 1. The cross-shaped first positioning telescopic arms 22 extending outwards simultaneously automatically clamp the inner wall of the steel pipe 1 and center its position. The magnetic positioning seat 24 improves the fixing effect between the first positioning telescopic arms 22 and the inner wall of the steel pipe 1.

[0036] The seam adjustment and positioning mechanism 3 includes a second main frame 31, several second positioning telescopic arms 32, several telescopic adjustment arms 33, several magnetic fixing seats 23, and several support arms 24; the second positioning telescopic arms 32 and telescopic adjustment arms 33 also use hydraulic cylinders; a walking mechanism is provided at the bottom of the second main frame 31; a second keel positioning shaft 312 is horizontally arranged at the center of the second main frame 31, and the second keel positioning shaft 312 is fixedly connected to the second main frame 31 around its periphery; two cross connecting seats 313 are also spaced apart on the second keel positioning shaft 312, and the two cross connecting seats 313 are distributed one on each side of the second main frame 31; the cross-shaped end of each cross connecting seat 313 is fixedly connected to one end of a second positioning telescopic arm 32, and each second positioning telescopic arm 32... The other end is fixedly connected to a magnetic fixing seat 24; a support arm 24 is provided between each pair of adjacent second positioning telescopic arms 32, and the two ends of the support arm 24 are fixedly connected to the middle of the corresponding second positioning telescopic arm 32; the second keel positioning shaft 312 is also fixedly connected to the middle of each second positioning telescopic arm 32 through a support arm 24; the second main frame 31 is located on one side of the first main frame 21; one end of the second keel positioning shaft 312 is slidably connected to one end of the first keel positioning shaft 212 through a shaft hole; the positions of adjacent first positioning telescopic arms 22 and second positioning telescopic arms 32 correspond one-to-one, and the corresponding first positioning telescopic arm 22 and second positioning telescopic arm 32 are connected through a telescopic adjustment arm 33. The first main frame 21 and the second main frame 31 have the same structure, both being assembled and welded from high-strength steel. Furthermore, the arrangement of the second positioning telescopic arm 32 is the same as that of the first positioning telescopic arm 22. The sliding connection between the first keel positioning shaft 212 and the second keel positioning shaft 312 is a clearance-fit shaft-hole connection. When the second positioning telescopic arm 32 and the first positioning telescopic arm 22 are not extended outwards, the first main frame 21 and the second main frame 31 are supported by the bottom walking mechanism. At this time, it is also necessary to ensure that the axial positions of the first keel positioning shaft 212 and the second keel positioning shaft 312 are consistent to facilitate docking. Considering the convenience of disassembling the two in actual use, the telescopic adjustment arm 33 can be bolted to the corresponding first positioning telescopic arm 22 and second positioning telescopic arm 32, and connected by a hinge for easy assembly and disassembly.In use, the positioning and centering mechanism 2 is located in one section of steel pipe 1, and the joint adjustment and positioning mechanism 3 is located in the adjacent section of steel pipe 1. When the first positioning telescopic arm 22 and the second positioning telescopic arm 32 extend outward at the same time, the first keel positioning shaft 212 and the second keel positioning shaft 312 are simultaneously positioned to the axial position of the steel pipe 1, realizing rapid positioning and centering. At this time, retracting the telescopic adjustment arm 33 allows the second main frame 31, the second keel positioning shaft 312, and the second positioning telescopic arm 32 to move a certain distance towards the positioning and centering mechanism 3 as a whole, thereby minimizing and maintaining the distance between the inner circumferential seams 5 of the two adjacent sections of steel pipe 1. This function is beneficial to the subsequent welding work and improves the welding quality.

[0037] The welding actuator 4 is located between the first main frame 21 and the second main frame 22. The welding actuator 4 includes an annular fixed seat 41, an annular rotating seat 42, an internal gear ring 43, a drive gear 44, a rotary drive motor 45, a multi-axis robotic arm 46, a welding torch 47, and a vision sensor 48. The inner ring 411 of the annular fixed seat 41 is fixedly connected to the first keel positioning shaft 212. The annular rotating seat 42 is rotatably connected to the outer ring 412 of the annular fixed seat 41. The internal gear ring 43 is coaxially fixed to one side of the annular rotating seat 42. The rotary drive motor 45... The rotating shaft of the rotary drive motor 45 is fixedly installed on the inner side of the outer ring 412 of the annular fixed seat 42. The rotating shaft is connected to the internal gear ring 43 through the drive gear 44 to drive the annular rotating seat 32 to rotate along the annular fixed seat 41. Several welding machine mounting seats 421 are distributed at equal angles on the other side of the annular rotating seat 42. Each welding machine mounting seat 421 is fixedly connected to the annular rotating seat 42. Each welding torch 47 is mounted on the welding machine mounting seat 421 through a multi-axis robotic arm 46. Each multi-axis robotic arm 46 is equipped with a vision sensor 48. Specifically, the annular fixed seat 42 includes an inner ring 411 and an outer ring 412 coaxially arranged, and a plurality of support rods 413 fixedly connected between the inner ring 411 and the outer ring 412. The support rods 413 are radially distributed at equal angles along the radial direction of the inner ring 411 and the outer ring 412. The inner ring 411 is welded and fixed to the first keel positioning shaft 212, and the outer ring 412 is rotatably connected to the annular rotating seat 42 through a large bearing. The internal gear ring 43 is coaxially fixed to one side of the annular rotating seat 42 with bolts. An infrared laser sensor 422 is provided on the outer peripheral side of the annular rotating seat 42. The number of infrared laser sensors 422 can be set to multiple, and they are distributed at equal angular intervals on the outer side of the annular rotating seat 42. During use, a cursor marker can be set at a suitable distance on one side of the inner ring seam 5. The infrared laser sensor 422 senses the position of the cursor marker to determine the relative position of the current annular rotating seat 42 and the inner ring seam 5. At this position, the positioning and centering mechanism 2 is controlled to support and fix the inner wall of the steel pipe 1 to achieve initial positioning and avoid exceeding the working radius of the multi-axis robotic arm 46 due to excessive placement of the positioning and centering mechanism 2. The multi-axis robotic arm 46, in conjunction with the vision sensor 48, accurately positions the weld seam and drives the welding torch 47 to align with the inner ring seam 5. The annular rotating seat 42 rotates at a constant speed, driving one welding torch 47 to automatically weld 360° along the inner ring seam, or driving multiple welding torches 47 to rotate a certain angle along the inner ring seam 5 so that multiple welding torches 47 can work together to complete the 360° welding work.Regarding the automatic welding technology based on vision recognition and positioning, such as the multi-axis robotic arm 46, vision sensor 48, and welding torch 47, various application methods have been disclosed in the prior art. For example, Chinese patent CN201910650355.8 discloses a method for automatic welding of small batches of customized irregular bridge steel templates by a robotic arm based on image vision recognition of weld seams. Therefore, this invention will not elaborate further. The side of the magnetic fixing seat 23 that is in contact with the inner wall of the steel pipe 1 is designed as a matching arc surface structure. The magnetic fixing seat 23 is provided with several mounting holes, and an electromagnet 231 is fixedly connected between each mounting hole. The magnetic end of the electromagnet 231 extends through the arc surface structure, and the outer contour of the magnetic end matches the arc surface structure. A pressure sensor is provided between each of the first positioning telescopic arms 22 and the corresponding magnetic fixing seat 23, and between each of the second positioning telescopic arms 32 and the corresponding magnetic fixing seat 23. The pressure sensor can monitor the supporting force in real time when it extends outward to abut against the inner wall of the steel pipe, preventing excessive clamping that could cause deformation of the pipe wall. A tension sensor is provided between each of the telescopic adjustment arms and the corresponding first positioning telescopic arm.

[0038] The present invention also includes a welding construction base 6, which is used to horizontally place the steel pipe 1 to be welded. The welding construction base 6 includes a positioning base 61 and several movable bases 62. The positioning base 61 is provided with several sets of positioning wheels 611 symmetrically distributed in an inverted figure-eight shape. The axle direction of each positioning wheel 611 is parallel to the axis direction of the steel pipe 1, so that each positioning wheel 611 is tangent to the outer peripheral wall of the steel pipe 1. Each movable base 62 is provided with several sets of pulleys 621 symmetrically distributed in an inverted figure-eight shape. The steel pipe 1 slides in the horizontal direction through the pulleys 621. The vertical distance from the axis of the steel pipe 1 to the foot of each positioning wheel 611 or each pulley 621 is equal, so as to minimize the coaxiality error when hoisting and placing the steel pipe. The positioning base 61 is equipped with a ratchet (not shown in the figure) and a ratchet locking handle 612 for each positioning wheel. The ratchet is coaxially fixed with the positioning wheel 611. Each ratchet locking handle 612 is installed on one side of the outer circumference of a ratchet. Each ratchet locking handle 612 extends and retracts along the positioning base 61 to lock the corresponding ratchet, thereby preventing the positioning wheel 611 from rolling.

[0039] The working steps and principles of this invention are as follows:

[0040] 1) Before deploying this device, a positioning base 61 and multiple movable bases 62 can be spliced ​​together to form a straight welded construction base 6 according to construction requirements.

[0041] 2) Hoist the steel pipes one by one onto the welding construction base 6. First, hoist the joint adjustment and positioning mechanism 3 into the first section of the steel pipe. Then, hoist the positioning and centering mechanism 2 into the first section of the steel pipe. Push the first main frame and the second main frame to align the first keel positioning shaft 212 with the second keel positioning shaft 312. After connecting the telescopic adjustment arm 33, push the entire device to the position of the first inner ring seam 5. At this time, the positioning and centering mechanism 2 and the joint adjustment and positioning mechanism 3 are respectively in a steel pipe 1.

[0042] 3) Set a cursor mark at a certain distance offset from the first inner ring seam 5 (the position depends on the working radius of the multi-axis robotic arm). Use the infrared laser sensor 422 to sense the position of the cursor mark and then determine the relative position of the current annular rotating seat 42 and the inner ring seam 5. At this position, control the first positioning telescopic arm 22 of the positioning and centering mechanism 2 and the second positioning telescopic arm 32 of the seam adjustment and positioning mechanism 3 to extend outward and abut against the inner wall of the corresponding two steel pipes 1 to support and fix the inner wall of the steel pipe 1 to achieve initial positioning.

[0043] 4) The annular rotating seat 42 rotates, driving the vision sensor on the multi-axis robotic arm 46 to perform a 360° scan of the inner annular seam 5 to calculate the welding path, and uploads the welding path to the control system. The control system feeds back to the multi-axis robotic arm 46, and the annular rotating seat 42 rotates again, driving the multi-axis robotic arm 46 to drive the welding gun 47 to perform automatic welding.

[0044] 5) The annular rotating seat 42 rotates for the third time, driving the vision sensor 48 on the multi-axis robotic arm 46 to perform visual inspection of the weld seam;

[0045] 6) If no abnormality is detected, retract the multi-axis robotic arm 46, and simultaneously retract the first positioning telescopic arm 22 and the second positioning telescopic arm 32 to fix the bottom walking mechanism and move to the next inner ring seam 5 position.

[0046] 7) By analogy, repeat steps 3) to 6) to complete the automatic welding of each inner circumferential seam 5 one by one.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the technical solutions of the present invention.

Claims

1. An automatic welding device for the inner circumferential seam of a large steel pipe, installed inside the steel pipe, characterized in that, This includes a positioning and alignment mechanism, a joint adjustment and positioning mechanism, and a welding execution mechanism; The positioning and centering mechanism includes a first main frame, a plurality of first positioning telescopic arms, a plurality of magnetic fixing seats, and a plurality of support arms. A walking mechanism is provided at the bottom of the first main frame. A first keel positioning shaft is horizontally arranged at the center of the first main frame. The keel positioning shaft is fixedly connected to the periphery of the first main frame. Two cross-shaped connecting seats are spaced apart on the first keel positioning shaft, distributed on both sides of the first main frame. The cross-shaped end of each cross-shaped connecting seat is fixedly connected to one end of a first positioning telescopic arm, and the other end of each first positioning telescopic arm is fixedly connected to a magnetic fixing seat. A support arm is provided between each pair of adjacent first positioning telescopic arms, with both ends of the support arm fixedly connected to the middle of a corresponding first positioning telescopic arm. The first keel positioning shaft is also fixedly connected to the middle of each first positioning telescopic arm via a support arm. The plurality of first positioning telescopic arms simultaneously extend outwards to allow the magnetic fixing seats to abut against the inner wall of the steel pipe. The seam adjustment and positioning mechanism includes a second main frame, several second positioning telescopic arms, several telescopic adjustment arms, several magnetic fixing seats, and several support arms; a walking mechanism is provided at the bottom of the second main frame; a second keel positioning shaft is horizontally arranged at the center of the second main frame, and the second keel positioning shaft is fixedly connected to the second main frame around its periphery. Two cross-shaped connecting seats are also spaced apart on the second keel positioning shaft, and the two cross-shaped connecting seats are distributed on both sides of the second main frame. The cross-shaped end of each cross-shaped connecting seat is fixedly connected to one end of a second positioning telescopic arm, and the other end of each second positioning telescopic arm is fixedly connected to a magnetic fixing seat. A support arm is provided between each pair of adjacent second positioning telescopic arms, and the two ends of the support arm are respectively fixedly connected to the middle of the corresponding second positioning telescopic arm; the second keel positioning shaft is also fixedly connected to the middle of each second positioning telescopic arm through a support arm; the second main frame is located on one side of the first main frame; one end of the second keel positioning shaft is slidably connected to one end of the first keel positioning shaft through a shaft hole; the positions of adjacent first positioning telescopic arms and second positioning telescopic arms correspond one-to-one, and a first positioning telescopic arm and a second positioning telescopic arm corresponding to each other are connected by a telescopic adjustment arm; The welding actuator is located between the first main frame and the second main frame. The welding actuator includes an annular fixed seat, an annular rotating seat, an internal gear ring, a drive gear, a rotary drive motor, a multi-axis robotic arm, a welding torch, and a vision sensor. The inner ring of the annular fixed seat is fixedly connected to the first keel positioning shaft. The annular rotating seat is rotatably connected to the outer ring of the annular fixed seat. The internal gear ring is coaxially fixed to one side of the annular rotating seat. The rotary drive motor is fixedly installed inside the outer ring of the annular fixed seat. The rotating shaft of the rotary drive motor is driven by the drive gear and the internal gear ring to drive the annular rotating seat to rotate along the annular fixed seat. Several welding machine mounting seats are distributed at equal angles on the other side of the annular rotating seat. Each welding machine mounting seat is fixedly connected to the annular rotating seat. Each welding torch is mounted on the welding machine mounting seat through a multi-axis robotic arm. Each multi-axis robotic arm is equipped with a vision sensor.

2. The automatic welding device for inner circumferential seams of large steel pipes according to claim 1, characterized in that, It also includes a welding construction base, which is used to horizontally place the steel pipe to be welded. The welding construction base includes a positioning base and several movable bases. The positioning base is provided with several sets of positioning wheels symmetrically distributed in an inverted figure-eight shape. The axle direction of each positioning wheel is parallel to the axis direction of the steel pipe, so that each positioning wheel is tangent to the outer peripheral wall of the steel pipe. Each movable base is provided with several sets of pulleys symmetrically distributed in an inverted figure-eight shape. The steel pipe slides horizontally through the pulleys. The distance from the axis of the steel pipe to the perpendicular foot of each positioning wheel or each pulley is equal.

3. The automatic welding device for inner circumferential seams of large steel pipes according to claim 2, characterized in that, The positioning base is equipped with a ratchet and a ratchet locking handle for each positioning wheel. The ratchet is coaxially fixed with the positioning wheel. Each ratchet locking handle is installed on one side of the outer circumference of a ratchet. Each ratchet locking handle extends and retracts along the positioning base to lock the corresponding ratchet.

4. The automatic welding device for inner circumferential seams of large steel pipes according to claim 1, characterized in that, The side of the magnetic fixing base that fits against the inner wall of the steel pipe is designed with a matching arc surface structure. The magnetic fixing base is provided with a plurality of mounting holes, and an electromagnet is fixedly connected between each mounting hole. The magnetic end of the electromagnet extends through the arc surface structure, and the outer contour of the magnetic end matches the arc surface structure.

5. The automatic welding device for inner circumferential seams of large steel pipes according to claim 3, characterized in that, A pressure sensor is provided between each of the first positioning telescopic arms and the corresponding magnetic fixing base, and between each of the second positioning telescopic arms and the corresponding magnetic fixing base.

6. The automatic welding device for inner circumferential seams of large steel pipes according to claim 1, characterized in that, A tension sensor is provided between each of the telescopic adjustment arms and the corresponding first positioning telescopic arm.

7. The automatic welding device for inner circumferential seams of large steel pipes according to claim 1, characterized in that, An infrared laser sensor is provided on the outer periphery of the annular rotating seat.

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