An automatic welding device for inner circumferential welds of steel pipes and its operating method

Abstract

This invention discloses an automatic welding device for inner circumferential welds of steel pipes and its operating method, relating to the field of pipeline welding technology. It includes a main frame, inside which a welding main unit is installed, and a traveling assembly at the bottom of the main frame. The main frame includes a cylindrical outer frame, with a base frame fixedly connected to its bottom. Multiple side frames are equidistantly fixed to the outer frame along its circumference, and guide and fixing assemblies are installed on the outer sides of each side frame. Multiple mounting plates are also fixedly connected to the outer frame, and detection assemblies are installed on the outer sides of the mounting plates. Each detection assembly includes a bottom shell, inside which a self-resetting pull rod displacement sensor is installed. An outer shell is movably sleeved on the outer shell, and a detection wheel is fixedly connected to the top of the outer shell. This invention uses the detection assemblies to detect displacement signals generated by undulations in the inner wall of the pipeline, adjusting the lifting height of the traveling assembly and the guide assemblies to prevent the device from getting stuck inside the pipeline, thus improving the device's passability and operational safety in complex pipeline environments.

Description

Technical Field

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

[0002] Internal circumferential welding of steel pipes is used in butt joints of long-distance pipelines, marine engineering pipelines and urban pipe networks. Compared with external welding, internal circumferential welding has the advantages of high weld formation quality, less susceptibility to external environmental interference and less damage to the outer surface of the pipeline. It is especially suitable for occasions with high requirements for the smoothness and sealing of the inner wall of the pipeline.

[0003] Currently, existing steel pipe internal welding devices typically rely on wheeled walking mechanisms in conjunction with guide structures for positioning and movement when moving inside the pipe. However, under long-term use or harsh working conditions, large-volume rust nodules, weld slag residue, deformed protrusions, and other obstacles can easily form inside the steel pipe. When the device encounters these protrusions, the walking mechanism often cannot detect and adjust them in time, which can easily lead to violent shaking of the device, obstruction of movement, or even jamming or overturning, seriously affecting the continuity and safety of welding operations.

[0004] To address these issues, we provide an automatic welding device for the inner circumferential weld seam of steel pipes and its operating method. Summary of the Invention

[0005] The purpose of this invention is to provide an automatic welding device for the inner circumferential weld of steel pipe and its operation method. By setting up a detection component to monitor the undulation of the inner wall of the pipe in real time and generate displacement signals, and with the adaptive adjustment of the walking component and the guiding component, the problem of jamming, shaking or even overturning of existing steel pipe internal welding devices when encountering rust nodules or protrusions on the inner wall of the pipe is solved.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0007] This invention relates to an automatic welding device for inner circumferential welds of steel pipes, comprising a main frame, inside which a welding main unit is installed, and at the bottom of the main frame a traveling component for driving the entire device to move within the pipe; the main frame includes a cylindrical outer frame, at the bottom of which a base frame for mounting the traveling component is fixedly connected; multiple side frames are equidistantly fixed to the outer frame along its circumference, and on the outer sides of each of the side frames are guide components for guiding the entire device to move stably within the pipe and fixing components for maintaining the stability of the entire device during welding; multiple mounting plates are also fixed to the outer frame, and on the outer side of each mounting plate are detection components for detecting protrusions inside the pipe to prevent the device from jamming; the detection component includes a bottom shell fixedly connected to the outside of the mounting plate, inside which a self-resetting pull rod displacement sensor is installed, and an outer shell is movably sleeved on the outside of the bottom shell, with a detection wheel fixedly connected to the top of the outer shell.

[0008] The invention is further configured such that the movable end of the self-resetting pull rod displacement sensor penetrates the top of the bottom shell and abuts against the top of the inner cavity of the outer shell; an ejector spring is installed between the bottom of the inner cavity of the outer shell and the top of the bottom shell.

[0009] The present invention is further configured such that the walking assembly includes a walking frame located below the base frame and a first electric cylinder fixedly connected to the top of the base frame for driving the walking frame to rise and fall; four limiting rods distributed in a rectangular pattern are fixedly connected to the top of the walking frame, and all four limiting rods are movably sleeved inside the base frame; at least one power wheel with independent power is installed inside the walking frame.

[0010] The present invention is further configured such that a first mounting chamber is provided at the top center of the walking frame, and a first pressure sensor is installed inside the first mounting chamber; a first cover plate is fixedly connected to the top of the first mounting chamber, and a first connecting rod with an inverted T-shaped longitudinal section is movably sleeved at the center of the first cover plate, and the first connecting rod is located above the first pressure sensor; the first connecting rod is detachably and fixedly connected to the output end of the first electric cylinder.

[0011] The present invention is further configured such that the guide assembly includes two telescopic tubes symmetrically and fixedly connected to the outside of the side frame, and a horizontal plate is fixedly connected to the top of the two telescopic tubes. Guide wheels are fixedly connected to the top of the horizontal plate near both ends. A second electric cylinder for driving the horizontal plate to move is also fixedly connected to the outside of the side frame, and the second electric cylinder is located at the midpoint of the line connecting the two telescopic tubes.

[0012] The present invention is further configured such that a second mounting compartment is provided at the center of the inner side of the horizontal plate, and a second pressure sensor is installed inside the second mounting compartment; a second cover plate is fixedly connected to the bottom of the second mounting compartment, and a second connecting rod with a T-shaped longitudinal section is movably sleeved at the center of the second cover plate, and the second connecting rod is located below the second pressure sensor;

[0013] The second connecting rod is detachably and fixedly connected to the output end of the second electric cylinder.

[0014] The present invention is further configured such that the fixing component includes a mounting base fixedly connected to the inner side of the horizontal plate, a sliding frame movably sleeved inside the horizontal plate, and a threaded sleeve rotatably connected to the inside of the horizontal plate; a screw is fixedly connected inside the sliding frame, and the screw is threadedly sleeved inside the threaded sleeve; one end of the sliding frame is located inside the mounting base, and the other end is fixedly connected to a fixing rubber sheet for abutting against the inner wall of the pipe; a fixing motor is fixedly connected to the end of the mounting base opposite to the horizontal plate, and the threaded sleeve is detachably fixedly connected to the output end of the fixing motor.

[0015] The invention is further configured such that an installation platform is fixedly connected inside the main frame, and the welding main unit is fixedly connected to the top of the installation platform.

[0016] The present invention is further configured such that a control component is provided inside the welding host, and the first electric cylinder, the first pressure sensor, the second electric cylinder, the second pressure sensor, and the self-resetting tie rod displacement sensor are all electrically connected to the control component inside the welding host.

[0017] The present invention also provides an operation method for an automatic welding device for inner circumferential welds of steel pipes, comprising the following welding operations:

[0018] S1: The automatic welding device is placed inside the steel pipe to be welded, and the walking component drives the device to move along the axial direction of the steel pipe.

[0019] S2: During the movement, the detection wheel of the detection component always adheres to the inner wall of the pipe under the action of the ejection spring. The self-resetting tie rod displacement sensor detects the radial displacement of the detection wheel in real time and transmits the displacement signal to the control component. When the displacement exceeds the preset threshold, the control component determines that there is a protruding obstacle in front and issues an alarm or stops the movement command.

[0020] S3: The control component adjusts the extension length of the first electric cylinder according to the feedback signal of the first pressure sensor, so as to raise and lower the walking frame, thereby adjusting the positive pressure between the power wheel and the inner wall of the pipe and preventing slippage.

[0021] S4: The control component adjusts the extension length of the second electric cylinder according to the feedback signal of the second pressure sensor, so as to raise and lower the horizontal plate, thereby adjusting the positive pressure between the guide wheel and the inner wall of the pipe and keeping the device moving in the center.

[0022] S5: When the device moves to the predetermined circumferential weld position, the control component controls the walking component to stop moving and starts the fixing component: the fixing motor drives the threaded sleeve to rotate, and drives the sliding frame to extend outward through the screw, so that the fixing rubber sheet is pressed against the inner wall of the pipe, thereby achieving relative fixation between the device and the pipe;

[0023] S6: Start the welding machine to perform circumferential welding;

[0024] S7: After welding is completed, the control component controls the fixed component to reset, so that the fixed rubber sheet is detached from the inner wall of the pipe, and the driving of the walking component is restored, so that the device is moved out of the pipe or moved to the next weld position.

[0025] The present invention has the following beneficial effects:

[0026] 1. The present invention uses a first pressure sensor in the walking assembly to monitor the contact pressure between the power wheel and the inner wall of the pipe in real time, and a second pressure sensor in the guiding assembly to provide feedback on the contact pressure between the guide wheel and the inner wall of the pipe. This enables the device to adapt to different pipe diameters and maintain a centered posture, thereby improving the passability and operational stability of the entire device in straight or variable diameter pipes.

[0027] 2. This invention utilizes the cooperative structure of the self-resetting pull rod displacement sensor and the ejector spring in the detection component to enable the detection wheel to generate displacement signals in real time by following the undulations of the inner wall of the pipe, and transmits them to the control component of the welding host. When a protruding obstacle is detected to exceed the safety threshold, an obstacle avoidance command is immediately issued, adjusting the lifting height of the walking component and the extension amount of the guide component, thereby preventing the device from getting stuck in the pipe and improving the device's passability and operational safety in complex pipe environments. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0030] Figure 2 This is a schematic diagram of the main frame of the present invention.

[0031] Figure 3 This is a cross-sectional structural diagram of the present invention.

[0032] Figure 4 This is a schematic diagram of the detection component of the present invention.

[0033] Figure 5 This is a schematic diagram of the structure of the guide component of the present invention.

[0034] Figure 6 This is a schematic diagram of the walking component of the present invention.

[0035] Figure 7 for Figure 3 A magnified structural diagram of point A in the middle.

[0036] Figure 8 for Figure 3 A magnified structural diagram at point B in the middle.

[0037] Figure 9 for Figure 3 A magnified structural diagram at point C.

[0038] The attached diagram lists the components represented by each number as follows:

[0039] 100. Main frame; 101. Outer frame; 102. Base frame; 103. Side frame; 104. Mounting plate; 105. Mounting platform; 200. Welding main unit; 300. Walking assembly; 301. Limiting rod; 302. Walking frame; 302a. First mounting compartment; 302b. First cover plate; 302c. First connecting rod; 303. Drive wheel; 304. First electric cylinder; 305. First pressure sensor; 400. Guide assembly; 401. Telescopic tube; 403. Horizontal plate; 403a. 2. Installation chamber; 403b. Second cover plate; 403c. Second connecting rod; 404. Guide wheel; 405. Second electric cylinder; 406. Second pressure sensor; 500. Fixing assembly; 501. Mounting base; 502. Threaded sleeve; 503. Sliding frame; 504. Fixing motor; 505. Fixing rubber sheet; 506. Screw; 600. Detection assembly; 601. Bottom shell; 602. Outer shell; 603. Self-resetting pull rod displacement sensor; 604. Detection wheel; 605. Ejection spring. Detailed Implementation

[0040] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Please see Figures 1 to 9This invention relates to an automatic welding device for inner circumferential welds of steel pipes, comprising a main frame 100, a welding main unit 200 installed inside the main frame 100, and a traveling component 300 for driving the entire device to move within the pipe at the bottom of the main frame 100; the main frame 100 includes a cylindrical outer frame 101, a base frame 102 for mounting the traveling component 300 fixedly connected to the bottom of the outer frame 101, and multiple side frames 103 equidistantly fixed to the outer side of the outer frame 101 along the circumference, each side frame 103 having a guide component 400 for guiding the entire device to move stably within the pipe and for maintaining the stability of the entire device during welding. The frame 101 is fixed with a fixed component 500; multiple mounting plates 104 are also fixedly connected to the outside of the frame 101, and a detection component 600 for detecting internal protrusions in the pipe to avoid device jamming is installed on the outside of the mounting plates 104; the detection component 600 includes a bottom shell 601 fixedly connected to the outside of the mounting plates 104, a self-resetting pull rod displacement sensor 603 is installed inside the bottom shell 601, an outer shell 602 is movably sleeved on the outside of the bottom shell 601, and a detection wheel 604 is fixedly connected to the top of the outer shell 602; the main frame 100 is also fixedly connected to the inside of the main frame 100, and the welding main unit 200 is fixedly connected to the top of the mounting platform 105.

[0042] Specifically, the walking component 300 can drive the entire device to move autonomously within the pipeline. The guide component 400 is equidistantly arranged around the outside of the side frame 103 to ensure that the device maintains a centered posture in straight or variable diameter pipe sections, preventing the device from tilting or leaning. The fixing component 500 securely locks the device to the inner wall of the pipeline before welding operations begin, providing rigid support for welding and improving the stability of weld formation. The detection component 600 adopts a movable sleeve structure of outer shell 602 and bottom shell 601, and in conjunction with self-resetting pull rod displacement sensor 603 and detection wheel 604, it can detect rust nodules or other protruding obstacles on the inner wall of the pipeline in real time, and feed back obstacle avoidance signals to the control system to prevent the device from jamming or being damaged.

[0043] Example 1

[0044] Please see Figure 3 , Figure 5 , Figure 6 , Figure 8 and Figure 9The walking assembly 300 includes a walking frame 302 located below the base frame 102 and a first electric cylinder 304 fixedly connected to the top of the base frame 102 for driving the walking frame 302 to rise and fall. Four rectangularly distributed limiting rods 301 are fixedly connected to the top of the walking frame 302, and all four limiting rods 301 are movably sleeved inside the base frame 102. At least one independently powered drive wheel 303 is installed inside the walking frame 302. A first mounting compartment 302a is provided at the center of the top of the walking frame 302, and a first pressure sensor 305 is installed inside the first mounting compartment 302a. A first cover plate 302b is fixedly connected to the top of the first mounting compartment 302a, and a first connecting rod 302c with an inverted T-shaped longitudinal section is movably sleeved at the center of the first cover plate 302b, with the first connecting rod 302c located above the first pressure sensor 305. The first connecting rod 302c is detachably fixedly connected to the first electric cylinder 304. Output end; the guide assembly 400 includes two telescopic tubes 401 symmetrically and fixedly connected to the outside of the side frame 103. A horizontal plate 403 is fixedly connected to the top of the two telescopic tubes 401. Guide wheels 404 are fixedly connected to the top of the horizontal plate 403 near both ends. A second electric cylinder 405 for driving the horizontal plate 403 to move is also fixedly connected to the outside of the side frame 103. The second electric cylinder 405 is located at the midpoint of the line connecting the two telescopic tubes 401. A second mounting chamber 403a is provided at the center of the inner side of the horizontal plate 403. A second pressure sensor 406 is installed inside the second mounting chamber 403a. A second cover plate 403b is fixedly connected to the bottom of the second mounting chamber 403a. A second connecting rod 403c with a T-shaped longitudinal section is movably sleeved at the center of the second cover plate 403b. The second connecting rod 403c is located below the second pressure sensor 406. The second connecting rod 403c is detachably and fixedly connected to the output end of the second electric cylinder 405.

[0045] In this embodiment, the first electric cylinder 304 drives the walking frame 302 to rise and fall. With the guidance of the limiting rod 301, the power wheel 303 can adapt to the inner wall of different pipe diameters and maintain stable contact with the ground. The first pressure sensor 305 monitors the downward pressure of the first electric cylinder 304 in real time, which facilitates the control of the contact pressure between the power wheel 303 and the inner wall of the pipe, preventing slippage or overload. The guide assembly 400 uses the second electric cylinder 405 in conjunction with the telescopic tube 401 to drive the horizontal plate 403 to move, so that the guide wheel 404 always fits against the inner wall of the pipe. The second pressure sensor 406 feeds back the pressure signal to ensure that the guide wheel 404 provides appropriate guiding force, thereby improving the device's passability and walking stability in straight or variable diameter pipes.

[0046] Example 2

[0047] Please see Figure 1 , Figure 3 , Figure 4 and Figure 7Based on the first specific embodiment, the movable end of the self-resetting pull rod displacement sensor 603 penetrates through the top of the bottom shell 601 and abuts against the top of the inner cavity of the outer shell 602; an ejector spring 605 is installed between the bottom of the inner cavity of the outer shell 602 and the top of the bottom shell 601; a control component is provided inside the welding host 200, and the first electric cylinder 304, the first pressure sensor 305, the second electric cylinder 405, the second pressure sensor 406 and the self-resetting pull rod displacement sensor 603 are all electrically connected to the control component inside the welding host 200.

[0048] In this embodiment, the ejector spring 605 ensures that the outer casing 602 is constantly subjected to an outward pushing force, thereby driving the probe wheel 604 to continuously adhere to the inner wall of the pipe. This ensures that the probe wheel 604 can generate corresponding radial displacement with the undulations of the inner wall of the pipe. When the device encounters rust nodules or other protruding obstacles on the inner wall of the pipe during its movement, the probe wheel 604 is pushed up by the protrusion and transmits displacement to the outer casing 602. The outer casing 602 slides inward relative to the bottom casing 601, compressing the ejector spring 605. At the same time, the top of the inner cavity of the outer casing 602 pushes the movable end of the self-resetting pull rod displacement sensor 603, causing the displacement sensor 603 to generate a displacement signal proportional to the height of the protrusion. This displacement signal is transmitted in real time to the control component inside the welding host 200. The control component determines whether the protrusion will affect the normal passage of the device or cause a risk of jamming based on a preset threshold. When the protrusion is detected... When the displacement exceeds the safety threshold, the control component immediately issues an obstacle avoidance command: on the one hand, the control component sends a signal to the first electric cylinder 304 of the walking component 300 to appropriately reduce the lifting height of the walking frame 302 or reduce the driving force of the power wheel 303, so that the device slows down or stops moving forward; on the other hand, the control component sends a signal to the second electric cylinder 405 of the guide component 400 to adjust the extension of the cross plate 403, so that the guide wheel 404 appropriately avoids or mitigates the impact of the protrusion. After the detection wheel 604 passes the protrusion, the push-out spring 605 pushes the outer shell 602 to reset, and the movable end of the self-resetting pull rod displacement sensor 603 returns to its original position, the displacement signal returns to zero, and the control component restores the normal walking parameters of the device after receiving the reset signal, thereby improving the device's passability and operational safety in complex pipeline environments and avoiding equipment damage caused by jamming.

[0049] Example 3

[0050] Please see Figure 3 , Figure 5 and Figure 8Based on specific embodiments one and two, the fixing component 500 includes a mounting base 501 fixedly connected to the inner side of the horizontal plate 403, a sliding frame 503 movably sleeved inside the horizontal plate 403, and a threaded sleeve 502 rotatably connected inside the horizontal plate 403; a screw 506 is fixedly connected inside the sliding frame 503, and the screw 506 is threadedly sleeved inside the threaded sleeve 502; one end of the sliding frame 503 is located inside the mounting base 501, and the other end is fixedly connected to a fixing rubber sheet 505 for abutting against the inner wall of the pipe; a fixing motor 504 is fixedly connected to the end of the mounting base 501 opposite to the horizontal plate 403, and the threaded sleeve 502 is detachably fixedly connected to the output end of the fixing motor 504.

[0051] In this embodiment, during welding operations, the threaded sleeve 502 is driven to rotate by the fixed motor 504, and the sliding frame 503 is pushed outward by the screw 506, so that the fixed rubber sheet 505 is tightly pressed against the inner wall of the pipe, thereby achieving a stable lock of the entire device. The rubber material can increase friction and avoid damage to the inner wall of the pipe. The fixing component 500 and the guide component 400 are integrated on the horizontal plate 403, which has a compact structure and rapid response. It can effectively suppress the displacement of the device caused by vibration or reaction force during the welding process and ensure the quality of weld formation.

[0052] Example 4

[0053] This embodiment is the fourth embodiment of the present invention. This embodiment provides an operation method for an automatic welding device for inner circumferential welds of steel pipes, which involves welding according to the following steps:

[0054] S1: Place the automatic welding device inside the steel pipe to be welded, and move it along the axial direction of the steel pipe through the driving device of the walking component 300.

[0055] S2: During the movement, the detection wheel 604 of the detection component 600 always adheres to the inner wall of the pipe under the action of the ejection spring 605. The self-resetting tie rod displacement sensor 603 detects the radial displacement of the detection wheel 604 in real time and transmits the displacement signal to the control component. When the displacement exceeds the preset threshold, the control component determines that there is a protruding obstacle in front and issues an alarm or a stop walking command.

[0056] S3: The control component adjusts the extension length of the first electric cylinder 304 according to the feedback signal of the first pressure sensor 305, so that the walking frame 302 is raised and lowered to adjust the positive pressure between the power wheel 303 and the inner wall of the pipe and prevent slippage.

[0057] S4: The control component adjusts the extension length of the second electric cylinder 405 according to the feedback signal of the second pressure sensor 406, so that the horizontal plate 403 is raised and lowered, thereby adjusting the positive pressure between the guide wheel 404 and the inner wall of the pipe and keeping the device moving in the center.

[0058] S5: When the device moves to the predetermined circumferential weld position, the control component controls the walking component 300 to stop moving and starts the fixing component 500: the fixing motor 504 drives the threaded sleeve 502 to rotate, and drives the sliding frame 503 to extend outward through the screw 506, so that the fixing rubber sheet 505 presses against the inner wall of the pipe, thereby achieving relative fixation between the device and the pipe.

[0059] S6: Start the welding host 200 to perform circumferential welding;

[0060] S7: After welding is completed, the control component controls the fixed component 500 to reset, so that the fixed rubber sheet 505 is detached from the inner wall of the pipe, and the drive of the walking component 300 is restored, so that the device is moved out of the pipe or moved to the next weld position.

[0061] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0062] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. An automatic welding device for inner circumferential welds of steel pipes, comprising a main frame (100), wherein a welding main unit (200) is installed inside the main frame (100), and a traveling assembly (300) for driving the entire device to move within the pipe is provided at the bottom of the main frame (100); characterized in that: The main frame (100) includes a cylindrical outer frame (101), and a base frame (102) for mounting the walking component (300) is fixedly connected to the bottom of the outer frame (101). Multiple side frames (103) are fixedly connected to the outside of the outer frame (101) at equal intervals along the circumference. Each of the multiple side frames (103) is equipped with a guide component (400) for guiding the entire device to move stably in the pipeline and a fixing component (500) for keeping the entire device stable during welding. The outer frame (101) is also fixed to the outside of a plurality of mounting plates (104), and the mounting plates (104) are equipped with detection components (600) for detecting protrusions inside the pipe to avoid device jamming. The detection assembly (600) includes a bottom shell (601) fixedly connected to the outside of the mounting plate (104), a self-resetting pull rod displacement sensor (603) is installed inside the bottom shell (601), an outer shell (602) is movably sleeved on the outside of the bottom shell (601), and a detection wheel (604) is fixedly connected to the top of the outer shell (602).

2. The automatic welding device for inner circumferential welds of steel pipes according to claim 1, characterized in that, The movable end of the self-resetting pull rod displacement sensor (603) penetrates the top of the bottom shell (601) and abuts against the top of the inner cavity of the outer shell (602); An ejector spring (605) is installed between the bottom of the inner cavity of the outer shell (602) and the top of the bottom shell (601).

3. The automatic welding device for inner circumferential welds of steel pipes according to claim 1, characterized in that, The walking assembly (300) includes a walking frame (302) located below the base frame (102) and a first electric cylinder (304) fixedly connected to the top of the base frame (102) for driving the walking frame (302) to rise and fall. The top of the walking frame (302) is fixedly connected with four rectangularly distributed limiting rods (301), and all four limiting rods (301) are movably sleeved inside the base frame (102). The walking frame (302) is equipped with at least one power wheel (303) with independent power.

4. The automatic welding device for inner circumferential welds of steel pipes according to claim 3, characterized in that, A first mounting chamber (302a) is provided at the top center of the walking frame (302), and a first pressure sensor (305) is installed inside the first mounting chamber (302a). The top of the first installation chamber (302a) is fixedly connected to a first cover plate (302b), and a first connecting rod (302c) with an inverted T-shaped longitudinal section is movably sleeved at the center of the first cover plate (302b), and the first connecting rod (302c) is located above the first pressure sensor (305). The first connecting rod (302c) is detachably and fixedly connected to the output end of the first electric cylinder (304).

5. The automatic welding device for inner circumferential welds of steel pipes according to claim 1, characterized in that, The guide assembly (400) includes two telescopic tubes (401) symmetrically fixedly connected to the outside of the side frame (103). A horizontal plate (403) is fixedly connected to the top of the two telescopic tubes (401). Guide wheels (404) are fixedly connected to the top of the horizontal plate (403) near both ends. The side frame (103) is also fixedly connected to a second electric cylinder (405) for driving the horizontal plate (403) to move, and the second electric cylinder (405) is located at the midpoint of the line connecting the two telescopic tubes (401).

6. The automatic welding device for inner circumferential welds of steel pipes according to claim 5, characterized in that, A second mounting chamber (403a) is provided at the center of the inner side of the horizontal plate (403), and a second pressure sensor (406) is installed inside the second mounting chamber (403a). The bottom of the second installation chamber (403a) is fixedly connected to a second cover plate (403b), and a second connecting rod (403c) with a T-shaped longitudinal section is movably sleeved at the center of the second cover plate (403b), and the second connecting rod (403c) is located below the second pressure sensor (406); The second connecting rod (403c) is detachably and fixedly connected to the output end of the second electric cylinder (405).

7. The automatic welding device for inner circumferential welds of steel pipes according to claim 1, characterized in that, The fixing component (500) includes a mounting base (501) fixedly connected to the inner side of the horizontal plate (403), a sliding frame (503) movably sleeved inside the horizontal plate (403), and a threaded sleeve (502) rotatably connected inside the horizontal plate (403). A screw (506) is fixedly connected inside the sliding frame (503), and the screw (506) is threadedly sleeved inside the threaded sleeve (502); One end of the sliding bracket (503) is located inside the mounting base (501), and the other end is fixedly connected to a fixing rubber sheet (505) for abutting against the inner wall of the pipe. The mounting base (501) is fixedly connected to a fixed motor (504) at one end away from the horizontal plate (403), and the threaded sleeve (502) is detachably and fixedly connected to the output end of the fixed motor (504).

8. The automatic welding device for inner circumferential welds of steel pipes according to claim 1, characterized in that, An installation platform (105) is also fixedly connected inside the main frame (100), and the welding main unit (200) is fixedly connected to the top of the installation platform (105).

9. An automatic welding device for inner circumferential welds of steel pipes according to any one of claims 1 to 8, characterized in that, The welding host (200) is equipped with a control component. The first electric cylinder (304), the first pressure sensor (305), the second electric cylinder (405), the second pressure sensor (406), and the self-resetting pull rod displacement sensor (603) are all electrically connected to the control component inside the welding host (200).

10. An operation method for an automatic welding device for inner circumferential welds of steel pipes according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1: The automatic welding device is placed inside the steel pipe to be welded, and the walking component (300) drives the device to move along the axial direction of the steel pipe; S2: During the movement, the detection wheel (604) of the detection component (600) always adheres to the inner wall of the pipe under the action of the ejector spring (605). The self-resetting tie rod displacement sensor (603) detects the radial displacement of the detection wheel (604) in real time and transmits the displacement signal to the control component. When the displacement exceeds the preset threshold, the control component determines that there is a protruding obstacle in front and issues an alarm or a stop walking command. S3: The control component adjusts the extension length of the first electric cylinder (304) according to the feedback signal of the first pressure sensor (305), so that the walking frame (302) is raised and lowered to adjust the positive pressure between the power wheel (303) and the inner wall of the pipe and prevent slippage; S4: The control component adjusts the extension length of the second electric cylinder (405) according to the feedback signal of the second pressure sensor (406), so that the horizontal plate (403) is raised and lowered to adjust the positive pressure between the guide wheel (404) and the inner wall of the pipe and keep the device moving in the center. S5: When the device moves to the predetermined circumferential weld position, the control component controls the walking component (300) to stop moving and starts the fixing component (500): the fixing motor (504) drives the threaded sleeve (502) to rotate, and drives the sliding frame (503) to extend outward through the screw (506), so that the fixing rubber sheet (505) presses against the inner wall of the pipe, thereby achieving relative fixation between the device and the pipe; S6: Start the welding host (200) to perform circumferential welding; S7: After welding is completed, the control component controls the fixed component (500) to reset, so that the fixed rubber sheet (505) is removed from the inner wall of the pipe, and the drive of the walking component (300) is restored to move the device out of the pipe or to the next weld position.

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