Welding device and welding method for bridge steel structure manufacturing

Abstract

The invention relates to the technical field of welding, and particularly discloses a welding device and method for manufacturing a bridge steel structure, and the welding device comprises a first rack, a second rack, a third rack and a fourth rack, a rotating table is rotationally mounted on the second rack; the two tool units are distributed on the two sides of the rotating table in a central symmetry mode, and each tool unit comprises a support fixed to the two ends of the rotating table, an overturning table rotationally installed on the support and an overturning motor fixed to the rotating table and used for driving the overturning table; the overturning table is provided with a pipe supporting piece, a pipe pressing piece, a positioning piece and an assembly piece, wherein the positioning piece and the assembly piece are matched with the round pipe and the sleeve plate. Through cooperation of the positioning piece and the assembly piece, precise axial positioning of the end of the circular pipe and the sleeve plate is achieved, the workpiece assembly coaxiality is improved, and the deflection problem existing in traditional assembly is avoided; a complete annular welding seam is formed through two-time welding of forward and reverse rotation of the overturning table, thermal deformation generated by single-side annular welding is avoided, heat accumulation in the annular welding process is effectively balanced, and the welding deformation amount is reduced.

Description

Technical Field

[0001] The present invention relates to the field of welding technology, and more particularly to a welding device and a welding method for manufacturing bridge steel structures. Background Art

[0002] As the core load-bearing component of modern long-span bridges, bridge steel structures have extremely high weld quality requirements, and must meet stringent standards such as fatigue resistance, corrosion resistance, and geometric accuracy. The assembly and welding of circular tubes and sleeves in bridge steel structures is the core process for constructing long-span tube trusses. The quality of the circumferential weld directly affects the structural load-bearing capacity and durability. In traditional welding processes, the sleeve plate needs to be manually aligned with the end of the round tube. Due to the weight of the sleeve plate and the deviation of the round tube during clamping, the assembly coaxiality is out of tolerance, and subsequent welding is prone to uneven fusion, which reduces the fatigue life of the joint. After the plate is assembled, there is a lack of bidirectional constraints, and the welding thermal cycle causes residual stress concentration, which accelerates the initiation of weld cracks and reduces the seismic performance of the structure. In addition, during unidirectional continuous girth welding, local high temperature causes ovality distortion of the circular tube, and the shrinkage of the sleeve due to heat causes axial displacement, which requires secondary flame correction, thereby affecting the overall performance and service life of the bridge steel structure. Summary of the Invention

[0003] In order to overcome the above technical problems, the present invention proposes a welding device and a welding method for manufacturing bridge steel structures.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A welding device for manufacturing a bridge steel structure is used for welding a bridge steel structure, wherein the bridge steel structure comprises a round tube and a sleeve plate sleeved on one end of the round tube; The welding device comprises: a first frame, on which a longitudinal drive member is provided, the longitudinal drive member is connected to a transverse drive member, and the transverse drive member is mounted with a welding gun; a second frame on which a rotating table is rotatably mounted, and a rotating motor for driving the rotating table is provided at the bottom of the second frame; The tooling unit is provided with two groups and is symmetrically distributed on both sides of the rotating table. It includes supports fixed on both ends of the rotating table, a flipping table rotatably installed on the supports, and a flipping motor fixed on the rotating table for driving the flipping table. The flipping table is provided with two groups of tube holders for supporting round tubes, and a pipe pressing part for clamping the round tube is provided between the two groups of tube holders. Positioning parts and assembly parts adapted to the round tube and the sleeve are respectively provided at both ends of the flipping table.

[0005] As a further solution of the present invention: the longitudinal driving component includes a longitudinal sliding rail fixed on the first frame and a longitudinal sliding platform slidingly arranged on the longitudinal sliding rail. A longitudinal motor is also fixed on the first frame. A longitudinal screw rod is installed at the output end of the longitudinal motor. The longitudinal sliding platform is threadedly connected to the longitudinal screw rod, and the transverse driving component is arranged on the longitudinal sliding platform.

[0006] As a further solution of the present invention: the transverse driving component includes a transverse slide rail fixed on the longitudinal slide and a transverse slide slidingly arranged on the transverse slide rail, the longitudinal slide is also fixed with a transverse motor, the output end of the transverse motor is connected to a transverse screw, the transverse slide is threadedly connected to the transverse screw, and the welding gun is installed on the transverse slide.

[0007] As a further solution of the present invention: the hosting member includes a first plate body fixed on the turning table, and a bracket adapted to the round tube is provided on the top of the first plate body.

[0008] As a further solution of the present invention: the pipe pressing member includes a turning cylinder fixed on the turning table, and the output end of the turning cylinder is connected to a turning fixture adapted to the round pipe.

[0009] As a further solution of the present invention: the positioning member includes a second plate body fixed on the turning table, the second plate body is provided with a positioning groove on a side facing the circular tube, and the top of the positioning groove is provided with an opening.

[0010] As a further solution of the present invention: the assembly part includes an assembly cylinder fixed on the turning table, and the output end of the assembly cylinder is respectively provided with a round tube assembly part adapted to the round tube and a sleeve plate assembly part adapted to the sleeve plate; The circular tube assembly comprises an inner clamping pin and an outer clamping ring which are coaxially fixed, and an annular clamping groove for accommodating the circular tube is formed between the inner clamping pin and the outer clamping ring; The sleeve plate assembly comprises side limiting plates symmetrically fixed on both sides of the round tube assembly, and the side limiting plates are provided with end face limiting plates adapted to the end faces of the sleeve plate.

[0011] As a further solution of the present invention, a top pin adapted to the sleeve plate is further provided on the hosting piece close to the side of the assembly piece.

[0012] As a further solution of the present invention: an axial chamber and a radial chamber are respectively provided in the inner pin, an axial airbag is provided in the axial chamber, a radial airbag is provided in the radial chamber, and an air passage connecting the axial airbag and the radial airbag is provided in the inner pin.

[0013] The present invention also discloses a welding method of a welding device for manufacturing a bridge steel structure, comprising the following steps: Step 1: Place the round tube in the tube holder and clamp it with the tube pressing fitting; the sleeve is guided by the assembly fitting and inserted into the outside of the round tube, while reinforcing the axial positioning of the round tube; Step 2: The longitudinal drive member and the transverse drive member are linked to adjust the welding gun to the starting point of the circumferential seam; Step 3: Start the welding gun and rotate the turning table 180° forward to complete the upper half of the circumferential seam welding; Step 4: Rotate the turning table 180° in the opposite direction, and use the welding gun to repair the lower half of the annular seam to form a complete annular weld.

[0014] Beneficial effects of the present invention: The present invention realizes precise axial positioning of the end of the round tube and the sleeve plate through the cooperation of the positioning member and the assembly member, and cooperates with the three-point clamping structure of the pipe pressing member to improve the coaxiality of the workpiece assembly and avoid the deflection problem existing in traditional assembly; A turning table that can rotate 180° in both directions is set up, and the horizontal and vertical linkage of the welding gun is coordinated to achieve automatic welding under single clamping. A complete circular weld is formed by two welding cycles in both directions, avoiding the thermal deformation caused by unilateral circular welding, effectively balancing the heat accumulation during the circular seam welding process, and reducing the welding deformation. The welding posture is adjusted by the flip table, and the welding gun performs trajectory compensation through the linear module. The two work together to ensure that the end of the welding gun and the weld always maintain the optimal welding angle, improving the uniformity of weld formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Figure 1 It is a three-dimensional schematic diagram of the present invention; Figure 2 A three-dimensional schematic diagram of another viewing angle of the present invention; Figure 3 Schematic diagram of the structure of the tooling unit in the present invention; Figure 4 Schematic diagram of the structure of the longitudinal driving member and the transverse driving member in the present invention; Figure 5 Schematic diagram of the structure of the turning table in the present invention; Figure 6 It is a structural schematic diagram of the assembly part in the present invention; Figure 7 Schematic diagram of the assembly of the round tube and the sleeve plate in the present invention; Figure 8 is a cross-sectional view of an assembly part in the present invention; Figure 9 for Figure 8 Enlarged view of point A in the middle.

[0017] In the picture: 100, first frame; 110, longitudinal drive member; 111, longitudinal slide rail; 112, longitudinal slide table; 113, longitudinal motor; 114, longitudinal screw rod; 120, transverse drive member; 121, transverse slide rail; 122, transverse slide table; 123, transverse motor; 124, transverse screw rod; 130, welding gun; 200, second frame; 210, rotating table; 300, tooling unit; 310, support; 320, turning table; 330, turning motor; 340, tube holder; 341, first plate; 342, bracket; 343, ejector pin; 350, tube pressing member; 351, turning cylinder; 352, turning fixture; 360, positioning member; 361, second plate; 362, positioning groove; 370, assembly member; 371, assembly cylinder; 372, round tube assembly member; 3721, inner retaining pin; 3722, outer retaining ring; 3723, annular retaining groove; 3724, axial chamber; 3725, axial airbag; 3726, radial chamber; 3727, radial airbag; 3728, airway; 373, sleeve assembly member; 3731, side limit plate; 3732, end limit plate; 400, bridge steel structure; 410, round tube; 420, sleeve plate. DETAILED DESCRIPTION

[0018] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed solely to enable those skilled in the art to better understand and implement the subject matter described herein, and that the functions and arrangements of the elements discussed may be varied without departing from the scope of this specification. Various examples may omit, substitute, or add various processes or components as needed. In addition, features described with respect to some examples may also be combined in other examples.

[0019] See also Figure 1 、 Figure 2 and Figure 3 The present invention discloses a welding device for manufacturing a bridge steel structure, which is used for welding a bridge steel structure 400. The bridge steel structure 400 includes a round tube 410 and a sleeve plate 420 sleeved on one end of the round tube 410. The welding device includes a first frame 100, a second frame 200 and a tooling unit 300. The first frame 100 is provided with a longitudinal driving member 110, the longitudinal driving member 110 is connected to a transverse driving member 120, and the transverse driving member 120 is installed with a welding gun 130; a rotating table 210 is rotatably installed on the second frame 200, and a rotating motor (not shown in the figure) for driving the rotating table 210 is provided at the bottom of the second frame 200; the tooling unit 300 is provided with two groups of rotating plates symmetrically distributed on the rotating table 210. 0 on both sides, including supports 310 fixed to both ends of the rotating platform 210, a flipping platform 320 rotatably mounted on the supports 310, and a flipping motor 330 fixed to the rotating platform 210 for driving the flipping platform 320. The flipping platform 320 is provided with two groups of tube holders 340 for supporting the round tube 410. A tube pressing member 350 for clamping the round tube 410 is provided between the two groups of tube holders 340. The two ends of the flipping platform 320 are respectively provided with positioning members 360 and assembly members 370 adapted to the round tube 410 and the sleeve plate 420; Specifically, the round tube 410 is placed on the two sets of tube holders 340, and one end of the round tube 410 is placed against the positioning member 360, and the sleeve plate 420 is placed in the assembly member 370; the round tube 410 is clamped and fixed by the tube pressing member 350, and the assembly member 370 drives the sleeve plate 420 to move axially toward one side of the round tube 410 until the sleeve plate 420 is sleeved at the specified position of the round tube 410. At the same time, the assembly member 370 positions and reinforces the round tube 410 and the sleeve plate 420; The welding gun 130 is driven to move longitudinally and transversely by the longitudinal driving member 110 and the transverse driving member 120 until the welding gun 130 moves to the connection between the circular tube 410 and the sleeve plate 420, the welding gun 130 is turned on, and at the same time, the flipping motor 330 drives the flipping table 320 to flip 180° in the forward direction at a uniform speed, and the welding gun 130 is used to weld a semi-annular weld on one side of the connection between the circular tube 410 and the sleeve plate 420; then the welding gun 130 is turned off, and the flipping motor 330 drives the flipping table 320 to flip and reset, and then the welding gun 130 is turned on again, and at the same time, the flipping motor 330 drives the flipping table 320 to flip 180° in the reverse direction at a uniform speed, and the welding gun 130 is used to weld a semi-annular weld on the other side of the connection between the circular tube 410 and the sleeve plate 420 until a complete annular weld is formed at the connection between the circular tube 410 and the sleeve plate 420.

[0020] It should be noted that the present invention achieves precise axial positioning of the end of the round tube 410 and the sleeve 420 through the cooperation of the positioning member 360 and the assembly member 370, and cooperates with the three-point clamping structure of the pipe pressing member 350 to improve the coaxiality of the workpiece assembly and avoid the deflection problem existing in traditional assembly; A turning table 320 capable of 180° rotation in both directions is provided, and the welding gun 130 is linked in both the horizontal and vertical directions to realize automatic welding under single clamping. A complete annular weld is formed by welding twice in both the forward and reverse directions, thus avoiding thermal deformation caused by unilateral annular welding, effectively balancing heat accumulation during the annular weld welding process, and reducing welding deformation. The welding posture is adjusted by the turning table 320, and the welding gun 130 performs trajectory compensation through the linear module. The two work together to ensure that the end of the welding gun 130 and the weld always maintain the optimal welding angle, thereby improving the uniformity of the weld formation.

[0021] In one embodiment, see Figure 4 The longitudinal driving member 110 includes a longitudinal sliding rail 111 fixed on the first frame 100 and a longitudinal sliding table 112 slidably arranged on the longitudinal sliding rail 111. A longitudinal motor 113 is also fixed on the first frame 100. A longitudinal screw rod 114 is installed at the output end of the longitudinal motor 113. The longitudinal sliding table 112 is threadedly connected to the longitudinal screw rod 114. The transverse driving member 120 is arranged on the longitudinal sliding table 112. Furthermore, the transverse driving member 120 includes a transverse slide rail 121 fixed on the longitudinal slide 112 and a transverse slide 122 slidably arranged on the transverse slide rail 121. A transverse motor 123 is also fixed on the longitudinal slide 112. The output end of the transverse motor 123 is connected to a transverse screw rod 124. The transverse slide 122 is threadedly connected to the transverse screw rod 124. The welding gun 130 is mounted on the transverse slide 122. Specifically, the longitudinal motor 113 drives the longitudinal screw rod 114 to rotate, thereby driving the longitudinal slide 112 to slide longitudinally along the longitudinal slide rail 111, so as to adjust the longitudinal position of the welding gun 130; similarly, the transverse motor 123 drives the transverse screw rod 124 to rotate, thereby driving the transverse slide 122 to slide transversely along the transverse slide rail 121, so as to adjust the transverse position of the welding gun 130; By cooperating with the longitudinal drive member 110 and the transverse drive member 120, the position of the welding gun 130 can be adjusted in the horizontal dimension so that the welding gun 130 can be positioned in coordination with the annular weld of the circular tube 410 and the sleeve plate 420, thereby improving welding accuracy.

[0022] It is worth noting that the longitudinal drive member 110 adopts a closed-loop control structure of longitudinal slide rail 111 + longitudinal screw rod 114 (driven by longitudinal motor 113), and the transverse drive member 120 realizes orthogonal movement through transverse slide rail 121 + transverse screw rod 124 (driven by transverse motor 123), thereby improving the repeatability of the two axes and coordinating with the real-time correction of the end posture of the welding gun 130, thereby effectively reducing the weld trajectory tracking error; Through the precise coordination of the longitudinal screw rod 114 and the transverse screw rod 124, the welding gun 130 can perform XY plane trajectory compensation in real time when the turning table 320 drives the workpiece to rotate, eliminating weld offset caused by fluctuations in the workpiece rotation speed and ensuring the continuous forming quality of complex annular welds. The longitudinal slide 111 and the transverse slide 121 use cross roller guides, and cooperate with the integral casting base of the longitudinal slide 112 and the transverse slide 122, so that the overall mechanism can maintain a low vibration amplitude under high-speed movement, avoiding porosity defects caused by mechanical vibration during welding.

[0023] In yet another embodiment, see Figure 5 The hosting member 340 includes a first plate 341 fixed on the turning table 320 , and a bracket 342 adapted to the round tube 410 is opened on the top of the first plate 341 ; Specifically, the round tube 410 is placed into the brackets 342 of the hosting members 340 on both sides, and the round tube 410 is preliminarily positioned and supported by the brackets 342 so that the round tube 410 can be subsequently adapted and connected with the positioning member 360 and the assembly member 370 .

[0024] Further, see Figure 5 The tube pressing member 350 includes a turning cylinder 351 fixed on the turning platform 320, and the output end of the turning cylinder 351 is connected to a turning fixture 352 adapted to the round tube 410; Specifically, the round tube 410 is placed in the bracket 342, and one end of the round tube 410 is pressed against the positioning piece 360. The flipping cylinder 351 can be used to drive the flipping fixture 352 to flip until the flipping fixture 352 contacts the outer circumferential surface of the round tube 410. The flipping fixture 352 can then be used to press and fix the round tube 410 on the two sets of hosting pieces 340 to prevent the round tube 410 from circumferential deflection and axial displacement relative to the flipping table 320 during the welding process, so as to ensure the subsequent welding accuracy.

[0025] For further information, see Figure 5 The positioning member 360 includes a second plate 361 fixed on the flip table 320, and a positioning groove 362 is formed on the side of the second plate 361 facing the circular tube 410, and an opening is provided at the top of the positioning groove 362; Specifically, in the process of placing the round tube 410 into the bracket 342, the end of the round tube 410 facing the positioning piece 360 also enters the positioning groove 362 through the opening at the top of the positioning groove 362. When the round tube 410 completely falls into the bracket 342, the round tube 410 is pushed axially toward the side of the positioning piece 360 until the end of the round tube 410 is in close contact with the inner wall of the positioning groove 362. The round tube 410 is then clamped and fixed by the tube pressing piece 350 to complete the clamping of the round tube 410.

[0026] It should be noted that the V-shaped bracket 342 of the tube holder 340 and the arc-shaped flip fixture 352 of the tube pressing member 350 form a three-point contact clamping mechanism, which, combined with the axial limit of the positioning groove 362, effectively reduces the radial runout of the round tube 410 after clamping and improves the axial positioning repeatability. The flip cylinder 351 drives the flip fixture 352 to rotate 90 degrees and press together. When unfolding, it avoids the workpiece placement path, and when pressing, it forms an enveloping clamp. Compared with the vertical downward pressing structure of the linear cylinder, it reduces the horizontal space occupied and is particularly suitable for the lateral clamping needs of large-diameter round tubes. The positioning groove 362 adopts a trapezoidal guide structure that is wide at the top and narrow at the bottom (the top opening width is 10mm larger than the diameter of the round tube, and the gap between the bottom and the outer diameter of the round tube is ≤0.3mm). Under the action of the deadweight of the round tube 410, it automatically slides into the precise centering position, realizing adaptive positioning during the clamping process. In addition, the inner surface of the flip clamp 352 is provided with staggered anti-slip grooves (groove depth 0.5mm, spacing 5mm), which, together with the polyurethane buffer pad (Shore hardness 80A) embedded in the surface of the bracket 342, provide a high friction coefficient (μ≥0.25) while avoiding pinching the surface of the pipe, ensuring that the round tube 410 has no circumferential slip during welding (clamping force ≥800N).

[0027] In further embodiments, see Figure 5 and Figure 6 The assembly part 370 includes an assembly cylinder 371 fixed on the turning table 320, and the output end of the assembly cylinder 371 is respectively provided with a round tube assembly part 372 adapted to the round tube 410 and a sleeve plate assembly part 373 adapted to the sleeve plate 420; See also Figure 6 The circular tube assembly part 372 includes an inner clamping pin 3721 and an outer clamping ring 3722 that are coaxially fixed. An annular clamping groove 3723 for accommodating the circular tube 410 is formed between the inner clamping pin 3721 and the outer clamping ring 3722; The sleeve plate assembly 373 includes side limit plates 3731 symmetrically fixed to both sides of the round tube assembly 372 , and an end surface limit plate 3732 adapted to the end surface of the sleeve plate 420 is provided on the side limit plates 3731 ; Specifically, see Figure 7 , put the sleeve plate 420 from top to bottom into the space between the two sets of side limit plates 3731. As the sleeve plate 420 falls freely, the two side limit plates 3731 limit the two side walls of the sleeve plate 420, so that the inner circular hole of the sleeve plate 420 remains coaxial with the circular tube 410; Subsequently, the entire circular tube assembly 372 and the sleeve plate assembly 373 are driven by the assembly cylinder 371 to synchronously move axially toward the side of the circular tube 410. The sleeve plate 420 is axially limited by the end surface limit plate 3732, pushing the sleeve plate 420 to be sleeved on the circular tube 410. At the same time, one end of the circular tube 410 enters the annular groove 3723, and the circular tube 410 is positioned both radially and axially by the inner retaining pin 3721 and the outer retaining ring 3722. It should be noted that when the end of the circular tube 410 contacts the inner wall of the annular groove 3723, the end surface limiting plate 3732 also pushes the sleeve plate 420 to the designated welding position on the circular tube 410; The inner retaining pin 3721 and outer retaining ring 3722 of the round tube assembly 372 form a double annular retaining groove 3723, and the symmetrical side limit plates 3731 of the sleeve assembly 373 form a guide channel. The assembly cylinder 371 is synchronously pushed forward to automatically align the inner hole of the sleeve 420 with the outer wall of the round tube 410, thereby reducing the coaxiality error of the assembly. The end stopper plate 3732 precisely matches the depth of the annular groove 3723. When the sleeve plate 420 is pushed to the welding position, the end of the circular tube 410 contacts the inner wall of the annular groove 3723, achieving synchronous control of the axial position of the sleeve plate 420 and the extended length of the circular tube 410, eliminating the cumulative error of the traditional positioning process. The inner retaining pin 3721 is made of elastic steel (hardness HRC45-50) to achieve radial elastic clamping of the round tube. The outer retaining ring 3722 provides axial restraint through conical locking. Combined with the V-shaped guide surface (angle 60°) of the side limit plate 3731, it ensures that the sleeve 420 does not tilt during the advancement process.

[0028] Further, see Figure 7 , a top pin 343 adapted to the sleeve plate 420 is further provided on the hosting member 340 near the side of the assembly member 370; When the end face limit plate 3732 pushes the sleeve plate 420 to move axially to the designated welding position on the circular tube 410, the ejector pin 343 also just penetrates into the sleeve plate 420, thereby utilizing the ejector pin 343 to position and axially support the lower end portion of the sleeve plate 420, and utilizing the double axial support of the ejector pin 343 and the end face limit plate 3732 to ensure the coaxiality of the sleeve plate 420 and the circular tube 410.

[0029] It should be noted that the ejector pin 343 and the end surface stop plate 3732 form an axial supporting structure that is symmetrical in the vertical direction, thereby achieving bidirectional locking of the sleeve plate 420 in the axial direction and reducing the coaxiality error between the sleeve plate 420 and the round tube 410 after assembly. The ejector pin 343 is spring-loaded (preload force 200N±10N) and has a 30° guide cone on its end. It automatically guides into the inner hole of the sleeve plate 420 during axial movement of the sleeve plate 420 and utilizes elastic deformation to compensate for the assembly clearance between the inner hole of the sleeve plate 420 and the outer diameter of the round tube 410, thus avoiding assembly jamming caused by rigid contact. The surface of the ejector pin 343 is machined with reverse serrations (tooth depth 0.2mm, tooth pitch 2mm). When the sleeve plate 420 experiences axial contraction due to welding heat, the serrations and the inner wall of the sleeve plate 420 create a self-locking effect, effectively suppressing the sleeve plate 420 from retracting and ensuring the stability of the assembly during welding. The clearance between the diameter of the ejector pin 343 and the inner hole of the sleeve plate 420 is controlled within the range of 0.1-0.3 mm, and a reinforcing rib (8 mm thick, 15 mm high) is provided at the root of the ejector pin 343 to withstand the bending moment (≤50 N·m) generated by the deadweight of the sleeve plate 420 and prevent the sleeve plate 420 from deflecting in the cantilever state.

[0030] For further information, see Figure 8 and Figure 9 The inner bayonet 3721 defines an axial chamber 3724 and a radial chamber 3726. The axial chamber 3724 defines an axial airbag 3725. The radial chamber 3726 defines a radial airbag 3727. The inner bayonet 3721 defines an air passage 3728 communicating with the axial airbag 3725 and the radial airbag 3727. Specifically, in the initial state, the axial airbag 3725 extends from the axial chamber 3724, while the radial airbag 3727 retracts into the radial chamber 3726; When the end of the circular tube 410 enters the annular groove 3723, the end of the circular tube 410 will gradually axially squeeze the axial airbag 3725, so that the axial airbag 3725 gradually retracts into the axial chamber 3724, and the gas in the axial airbag 3725 enters the radial airbag 3727 through the airway 3728, so that the radial airbag 3727 gradually extends radially from the radial chamber 3726, so that the radial airbag 3727 contacts the outer circumferential surface of the circular tube 410, so as to achieve further circumferential reinforcement of the circular tube 410 and ensure the coaxiality of the circular tube 410.

[0031] It is worth noting that the axial airbag 3725 and the radial airbag 3727 form a pressure coupling relationship through the air channel 3728. When the round tube 410 is inserted, the axial compression is converted into a radial expansion force, achieving dynamic matching between the clamping force and the position of the workpiece, thereby improving the radial positioning accuracy of the round tube. The axial airbag 3725 is made of silicone rubber (hardness 30A Shore A), which can absorb the axial dimensional tolerance of the tube end face of ±0.5mm. The radial airbag 3727 has a built-in multi-layer aramid reinforcement layer. After expansion, it generates uniform radial pressure (adjustable from 0.2-0.8MPa), automatically compensating for the machining error of the tube outer diameter of ±0.3mm, improving the clamping adaptability. The surface of the radial airbag 3727 is equipped with an array of raised structures (2mm in diameter, 4mm in spacing). When expanded, they form multi-point flexible contact, reducing the peak contact stress from 15MPa of traditional hard contact to below 3MPa, avoiding local deformation of the thin-walled circular tube 410 and effectively controlling the ovality of the workpiece. A temperature compensation valve is installed inside the airbag system. When the welding temperature rise causes the circular tube 410 to expand, the radial airbag 3727 automatically releases 5%-15% of the air pressure through the air channel 3728, avoiding stress concentration caused by over-constraint and improving the thermal deformation suppression effect by 60%. The pneumatic system does not require an external air source and relies on mechanical extrusion to achieve pressure transmission. The response time from the circular tube 410 contacting the axial airbag 3725 to the complete expansion of the radial airbag 3727 is ≤ 0.3 seconds, effectively improving clamping efficiency.

[0032] The present invention also discloses a welding method of a welding device for manufacturing a bridge steel structure, comprising the following steps: Step 1: Place the round tube 410 in the tube holder 340 and clamp it with the tube pressing member 350; guide the sleeve 420 through the assembly member 370 and insert it into the outside of the round tube 410, while axially positioning and reinforcing the round tube 410; Step 2: The longitudinal driving member 110 and the transverse driving member 120 are linked to adjust the welding gun 130 to the starting point of the circumferential seam; Step 3: The welding gun 130 is started, and the turning table 320 is rotated 180° in the forward direction to complete the upper half of the annular seam welding; Step 4: The turning table 320 rotates 180° in the opposite direction, and the welding gun 130 repairs the lower half of the annular seam to form a complete annular weld.

[0033] The above describes the specific embodiments of the present invention, but the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the guidance of the present invention, those skilled in the art can also make many forms, all of which are protected by the present invention.

Claims

1. A welding device for manufacturing a bridge steel structure, used for welding a bridge steel structure (400), wherein the bridge steel structure (400) comprises a round tube (410) and a sleeve plate (420) sleeved on one end of the round tube (410); It is characterized in that The welding device comprises: a first frame (100) on which a longitudinal drive member (110) is provided, the longitudinal drive member (110) being connected to a transverse drive member (120), and a welding gun (130) being mounted on the transverse drive member (120); A second frame (200) on which a rotating platform (210) is rotatably mounted, and a rotating motor for driving the rotating platform (210) is provided at the bottom of the second frame (200); The tooling unit (300) is provided with two groups and is centrally symmetrically distributed on both sides of the rotating table (210), including supports (310) fixed to both ends of the rotating table (210), a flip table (320) rotatably mounted on the supports (310), and a flip motor (330) fixed to the rotating table (210) for driving the flip table (320), wherein the flip table (320) is provided with two groups of tube holders (340) for supporting the circular tube (410), and a tube pressing member (350) for clamping the circular tube (410) is provided between the two groups of tube holders (340), and a positioning member (360) and an assembly member (370) adapted to the circular tube (410) and the sleeve (420) are respectively provided at both ends of the flip table (320).

2. A welding device for manufacturing bridge steel structures according to claim 1, characterized in that: The longitudinal driving member (110) includes a longitudinal sliding rail (111) fixed on the first frame (100) and a longitudinal sliding platform (112) slidably arranged on the longitudinal sliding rail (111); a longitudinal motor (113) is also fixed on the first frame (100); a longitudinal screw rod (114) is installed at the output end of the longitudinal motor (113); the longitudinal sliding platform (112) is threadedly connected to the longitudinal screw rod (114); and the transverse driving member (120) is arranged on the longitudinal sliding platform (112).

3. A welding device for manufacturing bridge steel structures according to claim 2, characterized in that: The transverse driving member (120) includes a transverse slide rail (121) fixed on the longitudinal slide (112) and a transverse slide (122) slidably arranged on the transverse slide rail (121); a transverse motor (123) is also fixed on the longitudinal slide (112); an output end of the transverse motor (123) is connected to a transverse screw rod (124); the transverse slide (122) is threadedly connected to the transverse screw rod (124); and the welding gun (130) is installed on the transverse slide (122).

4. A welding device for manufacturing bridge steel structures according to claim 1, characterized in that: The tube holder (340) comprises a first plate (341) fixed on the turning platform (320), and a bracket (342) adapted to the circular tube (410) is provided on the top of the first plate (341).

5. A welding device for manufacturing bridge steel structures according to claim 4, characterized in that: The pipe pressing member (350) comprises a turning cylinder (351) fixed on the turning platform (320), and an output end of the turning cylinder (351) is connected to a turning fixture (352) adapted to the round pipe (410).

6. The welding device for manufacturing bridge steel structure according to claim 1, characterized in that: The positioning member (360) comprises a second plate (361) fixed on the turning platform (320), and a positioning groove (362) is provided on a side of the second plate (361) facing the circular tube (410), and an opening is provided at the top of the positioning groove (362).

7. The welding device for manufacturing bridge steel structure according to claim 1, characterized in that: The assembly part (370) includes an assembly cylinder (371) fixed on the turning table (320), and the output end of the assembly cylinder (371) is respectively provided with a round tube assembly part (372) adapted to the round tube (410) and a sleeve plate assembly part (373) adapted to the sleeve plate (420); The circular tube assembly (372) comprises an inner retaining pin (3721) and an outer retaining ring (3722) that are coaxially fixed, and an annular retaining groove (3723) for accommodating the circular tube (410) is formed between the inner retaining pin (3721) and the outer retaining ring (3722); The sleeve plate assembly (373) comprises side limiting plates (3731) symmetrically fixed to both sides of the circular tube assembly (372), and the side limiting plates (3731) are provided with end face limiting plates (3732) adapted to the end face of the sleeve plate (420).

8. A welding device for manufacturing bridge steel structures according to claim 7, characterized in that: A top pin (343) adapted to the sleeve plate (420) is further provided on the hosting member (340) on the side close to the assembly member (370).

9. A welding device for manufacturing bridge steel structures according to claim 7, characterized in that: An axial chamber (3724) and a radial chamber (3726) are respectively provided in the inner retaining pin (3721), an axial airbag (3725) is provided in the axial chamber (3724), a radial airbag (3727) is provided in the radial chamber (3726), and an air passage (3728) connecting the axial airbag (3725) and the radial airbag (3727) is provided in the inner retaining pin (3721).

10. A welding method using the welding device for manufacturing a bridge steel structure according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Place the round tube (410) in the tube holder (340) and clamp it with the tube pressing member (350); guide the sleeve (420) through the assembly member (370) and insert it into the outside of the round tube (410), while axially positioning and reinforcing the round tube (410); Step 2: The longitudinal driving member (110) and the transverse driving member (120) are linked to adjust the welding gun (130) to the starting point of the annular seam; Step 3: The welding gun (130) is started, and the turning table (320) is rotated 180° in the forward direction to complete the upper half of the annular seam welding; Step 4: The turning table (320) is rotated 180° in the opposite direction, and the welding gun (130) is used to repair the lower half of the annular seam to form a complete annular weld.

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