Multi-angle positioning welding special fixture

Abstract

This invention relates to the field of welding fixture technology and discloses a multi-angle positioning welding fixture, including a support platform. External roller modules are symmetrically mounted on the surface of the support platform, and double-end internal support modules are symmetrically mounted on the surface of the support platform. Each double-end internal support module includes a sleeve, which is inserted into the interior of a bimetallic composite tube. Through the elastic floating structure of the movable contact block and the reset elastic element in the movable telescopic end, adaptive avoidance of welding thermal deformation of the bimetallic composite tube is achieved. The movable contact block is slidably connected inside the inclined sleeve, and the reset elastic element provides radial elastic reset force, allowing the front elastic short support block to synchronously and radially retract. During welding, when the high temperature in the weld area causes thermal expansion of the inner thin wall, the movable contact block can overcome the elastic force of the reset elastic element and synchronously retract, reserving sufficient space for the inner thermal expansion and completely avoiding the problems of bulging, wrinkling, crushing, and even interlayer delamination caused by traditional rigid supports.

Description

Technical Field

[0001] This invention relates to the field of welding fixture technology, specifically a welding fixture for multi-angle positioning. Background Technology

[0002] Bimetallic composite pipes, a new type of pipe material combining the strength of an outer metal layer with the corrosion resistance of an inner layer, are widely used in pipeline transportation projects in petrochemical, energy, and marine engineering fields. During the installation and construction of bimetallic composite pipes, circumferential welding is a crucial process that determines the sealing performance, structural strength, and service life of the pipeline system. However, due to the significant difference in thermal expansion coefficients between the inner and outer layers of bimetallic composite pipes and the high requirements for interlayer bonding strength, the welding operation places much higher technical demands on positioning accuracy, support stability, and thermal deformation control than on ordinary pipe materials.

[0003] Currently, welding operations for bimetallic composite pipes mostly use general-purpose welding fixtures or simple support structures, which are difficult to meet their special welding requirements and generally have many technical defects and industry pain points.

[0004] Firstly, the concentricity positioning accuracy is insufficient. Existing fixtures mostly rely on external rollers or simple chucks for clamping, lacking a precise centering mechanism for the inner layer of the composite pipe. This makes it impossible to guarantee the coaxiality between the inner and outer layers. During the welding process, the pipe is prone to deviations such as eccentricity and tilting, resulting in uneven weld wall thickness and excessive misalignment. This seriously affects the mechanical properties and sealing effect of the welded joint, and is very likely to cause the risk of pipeline leakage later.

[0005] Secondly, the ability to avoid thermal deformation is lacking. The temperature in the weld area is extremely high during the welding of bimetallic composite pipes. The inner metal of the pipe expands significantly due to heat, resulting in a significant expansion of the pipe diameter. Existing clamps mostly use rigid internal supports or fixed clamping structures, which cannot provide space for thermal expansion deformation. The mutual compression between the rigid support and the thermal expansion of the pipe often leads to stress deformation, local cracking, or even interlayer peeling in the inner layer of the composite pipe, causing the finished pipe to be scrapped directly.

[0006] Third, the welding efficiency and quality stability are poor. Existing technologies usually adopt a single-end welding and step-by-step operation method. After completing the welding of one end, the pipe needs to be flipped or repositioned before welding the other end. This method is not only cumbersome and labor-intensive, but also prone to slippage and vibration due to the asynchronous rotation speed of the pipe and the support during the welding process. This results in rough weld formation and inconsistent parameters, making it difficult to meet the efficiency and quality requirements of mass production and automated production.

[0007] Therefore, this invention proposes a welding fixture with multi-angle positioning. Summary of the Invention

[0008] The purpose of this invention is to provide a welding fixture with multi-angle positioning to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a multi-angle positioning welding fixture for coaxial positioning and support of bimetallic composite pipes, comprising a bearing platform, on the surface of which external roller modules are symmetrically mounted, and on the surface of which double-end internal support modules are symmetrically mounted, each of which includes a sleeve inserted into the bimetallic composite pipe. The sleeve has a fixed telescopic end and a movable telescopic end respectively mounted on its surface. A central shaft is slidably connected inside the sleeve. A driving module is provided on the outside of the sleeve, the driving module being used to drive the central shaft to move and the sleeve to rotate.

[0010] When the central shaft moves along the sleeve axial direction, it synchronously drives the fixed telescopic end and the movable telescopic end to extend radially and support the inner wall of the bimetallic composite pipe, realizing high-precision coaxial positioning of the bimetallic composite pipe. The movable telescopic end has radial elastic floating capability, which can synchronously radially retreat when the pipe expands and contracts due to the high temperature of welding, avoiding stress deformation or cracking of the inner layer due to rigid support.

[0011] During the welding process, the outer roller module and the double-end inner support module synchronously drive the bimetallic composite pipe to rotate, keeping the welding gun fixed, thus achieving synchronous welding of the circumferential seam at both ends of the pipe, improving welding accuracy and welding efficiency.

[0012] Preferably, the fixed telescopic end includes several fixed grooves formed on the surface of the sleeve, and a fixed inclined block is slidably connected inside each fixed groove. A synchronization hole is formed through the surface of each fixed inclined block, and a fixed elastic element is provided inside the synchronization hole. The movable telescopic end includes several movable grooves formed on the surface of the sleeve, and a movable element is slidably fitted inside each movable groove.

[0013] Preferably, a plurality of abutting inclined blocks are fixedly connected to the surface of the central shaft. When the central shaft moves axially along the inside of the sleeve, each abutting inclined block abuts against the inclined surface of the corresponding fixed inclined block and the movable part through the inclined surface, and simultaneously pushes the fixed inclined block along the fixed groove and the movable part along the movable groove to extend radially outward.

[0014] Preferably, each of the movable components includes an inclined shell and a movable abutment block. The inclined shell and the movable abutment block are slidably fitted inside the movable groove, and the movable abutment block is slidably connected inside the inclined shell. A second synchronization hole is provided through the surface of the movable abutment block, and a number of second synchronization holes are provided with movable elastic elements.

[0015] Preferably, a reset elastic element is fixedly connected between the movable abutment block and the inclined shell, and the reset elastic element is used to realize the radial elastic floating function of the movable telescopic end.

[0016] Preferably, when the central shaft moves axially, the abutting block abuts against the inclined surface shell through the inclined surface, driving the movable abutting block to extend radially synchronously and abut against the inner wall of the bimetallic composite tube.

[0017] When the high temperature of welding causes the pipe to expand and contract, the movable contact block overcomes the elastic force of the reset elastic element and retracts radially along the inclined shell to avoid stress deformation or cracking of the inner layer due to rigid support. After welding is completed, the reset elastic element drives the movable contact block to automatically reset.

[0018] Preferably, the fixed telescopic end is located away from the port of the bimetallic composite pipe, and the movable telescopic end is located close to the port of the bimetallic composite pipe. The fixed telescopic end is used to provide rigid positioning support for the bimetallic composite pipe at a position away from the weld, and the movable telescopic end is used to provide elastic floating support for the bimetallic composite pipe at a position close to the weld, so as to adapt to the thermal expansion and contraction deformation of the pipe port during the welding process.

[0019] Preferably, the drive module includes a mounting plate mounted on a support platform, a cylinder mounted on the mounting plate, the output shaft of the cylinder being fixedly connected to the central shaft, and a motor mounted on the mounting plate.

[0020] Preferably, a gear is hinged to the mounting plate, the output shaft of the motor is connected to the gear transmission, and a number of teeth are fixedly connected to the outer surface of the sleeve. The gear meshes with the teeth to drive the sleeve to rotate synchronously.

[0021] Preferably, the tube bearing position formed by the outer roller module is on the same axis as the sleeve, so that the sleeve automatically maintains a coaxial state when inserted into the bimetallic composite tube.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. Through the elastic floating structure of the movable abutment block and the reset elastic element in the movable telescopic end, adaptive avoidance of thermal deformation during welding of bimetallic composite pipe is achieved. The movable abutment block is slidably connected inside the inclined shell, and the reset elastic element provides radial elastic reset force, allowing the front elastic short support block to synchronously and radially retract as a whole. During welding, when the high temperature in the weld area causes thermal expansion of the inner thin wall, the movable abutment block can overcome the elastic force of the reset elastic element and synchronously retract, reserving sufficient space for the thermal expansion of the inner layer, completely avoiding the problems of bulging, wrinkling, crushing, and even interlayer delamination caused by traditional rigid supports. During the cooling stage, the reset elastic element drives the movable abutment block to automatically reset, continuously adhering to the inner wall, ensuring the quality of welding formation, perfectly adapting to the thermal deformation problem caused by the difference in thermal expansion coefficients of the inner and outer layers of the bimetallic composite pipe, and significantly improving the finished product qualification rate.

[0024] 2. Through the two-section internal support structure of the double-end internal support module in this invention, namely the coordinated cooperation of the fixed telescopic end and the movable telescopic end, high-precision coaxial positioning of the bimetallic composite pipe is achieved. The fixed telescopic end, which is far from the weld seam, adopts a rigid long support block design. Multiple sets of fixed inclined blocks driven by the central axis extend radially synchronously, providing 360° uniform rigid support to the inner wall of the composite pipe. This provides a stable positioning reference for the entire pipe from a position far from the weld seam, completely solving the problems of eccentricity and out-of-roundness during pipe clamping and rotation. The movable telescopic end, which is close to the weld seam, ensures port support without compromising overall coaxiality. The internal support modules at both ends operate synchronously with the same driving logic, ensuring that the coaxiality of the weld joints at both ends is completely consistent. This fundamentally avoids defects such as welding misalignment and uneven wall thickness, significantly improving the mechanical properties and sealing reliability of the welded joint, and providing core protection for the safe operation of long-distance pipelines.

[0025] 3. Through the synchronous linkage structure of the symmetrical double-end inner support module and the outer clamping roller module of this invention, synchronous welding of the circumferential seams at both ends of the bimetallic composite pipe is realized. The sleeves on both sides rotate synchronously at the same speed under the drive of the corresponding motors and gears. The rotation speed of the outer clamping roller module is perfectly matched with the rotation speed of the sleeves, so that the composite pipe rotates around the axis at a constant speed in a stable posture. The operator can fix two welding guns at the weld positions at both ends of the pipe respectively, and complete the continuous welding of the circumferential seams at both ends simultaneously in one clamping. There is no need for secondary clamping or turning welding, which greatly reduces clamping time and labor costs. The welding efficiency is significantly improved compared with traditional fixtures. At the same time, synchronous welding completely avoids the influence of pipe thermal deformation after single-end welding on the welding accuracy of the other end, ensuring that the process parameters and forming quality of the welds at both ends are completely consistent, which is suitable for the high-efficiency operation requirements of large-scale, automated production lines.

[0026] 4. The rigid, large-area contact structure of the fixed telescopic end and the synchronous drive design of the external roller module achieve absolute stability during the welding rotation of the bimetallic composite pipe. Multiple sets of fixed inclined blocks extend radially synchronously at the fixed telescopic end to contact the inner wall of the composite pipe over a large area, providing sufficient static friction and stable driving force for pipe rotation from within. The pipe bearing position formed by the external roller module is concentric with the sleeve axis, and its rotation speed is completely consistent with the sleeve, providing support and synchronous rotational force for the pipe from the outside. This internal and external synchronous drive structure ensures smooth pipe rotation without slippage or swaying, completely solving the problems of uneven speed, vibration, and misalignment caused by traditional single-end drive fixtures. This ensures that the welding speed and forming quality at both ends remain highly consistent, effectively improving the welding qualification rate and reducing subsequent rework costs.

[0027] 5. This invention adopts a purely mechanical transmission structure, without complex electrical control or hydraulic components. Core components such as the outer roller, two-section inner support, springs, gears, and cylinders are all standard mechanical parts, which are easy to process and have low procurement costs, significantly reducing equipment manufacturing and maintenance costs. During the installation and commissioning phase, only the concentricity of the outer roller module and the sleeve needs to be calibrated and the preload of the elastic element needs to be adjusted to complete the commissioning. No professional technicians are required. Routine maintenance only requires periodic checks on the fatigue of the elastic element and the meshing status of the gears, making maintenance convenient and suitable for rapid promotion and use in on-site construction scenarios. At the same time, the modular structural design facilitates component replacement and maintenance, further reducing the total life cycle cost of the equipment and improving the economic benefits of the project. Attached Figure Description

[0028] Figure 1 This is a frontal perspective three-dimensional schematic diagram of the main structure of the present invention;

[0029] Figure 2 This is a three-dimensional schematic diagram of the main structure of the present invention in an adjusted state;

[0030] Figure 3 This is a three-dimensional schematic diagram showing the relationship between the main structure of the present invention and the composite pipe.

[0031] Figure 4 This is a three-dimensional schematic diagram of the double-ended internal support module of the present invention;

[0032] Figure 5 This is a cross-sectional plan view of the double-ended internal support module of the present invention;

[0033] Figure 6 This is a three-dimensional disassembly diagram of the double-ended internal support module of the present invention;

[0034] Figure 7 This is a partial three-dimensional schematic diagram of the fixed telescopic end of the present invention;

[0035] Figure 8 This is a partial three-dimensional schematic diagram of the movable telescopic end of the present invention;

[0036] Figure 9 This is a three-dimensional schematic diagram of the movable component of the present invention.

[0037] In the picture:

[0038] 1. Bearing platform; 2. External roller module; 3. Double-end internal support module; 31. Sleeve; 32. Fixed telescopic end; 321. Fixed groove; 322. Fixed inclined block; 323. Fixed elastic element; 33. Movable telescopic end; 331. Movable groove; 332. Movable element; 3321. Inclined shell; 3322. Movable abutment block; 3323. Movable elastic element; 3324. Reset elastic element; 34. Central shaft; 341. Abutment inclined block; 35. Drive module; 351. Tooth; 352. Gear; 353. Motor; 354. Cylinder; 355. Mounting plate. Detailed Implementation

[0039] 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 protection scope of the present invention.

[0040] It should be noted that the working principle and specific structure of the aforementioned external roller module 2, welding torch, and motor 353 in drive module 35 are all existing technologies. The external roller module 2 adopts an electric drive roller structure to provide external support and synchronous rotation driving force for the bimetallic composite pipe. Together with the double-end inner support module 3, it drives the pipe to rotate smoothly and avoids slippage and misalignment of the pipe during welding. The welding torch is the execution component for welding operations and is used to complete fusion welding at the circumferential seam at both ends of the pipe. It can be fixed in a preset position according to the welding process requirements to achieve continuous and uniform circumferential seam welding. The motor 353, as the rotational power core of the double-end inner support module 3, provides driving force for the rotation of gear 352. By converting electrical energy into mechanical energy, it drives the sleeve 31 and the external roller module 2 to rotate synchronously and at the same speed, so as to achieve stable rotation of the bimetallic composite pipe and synchronous welding operations at both ends. Given the universality of the above structure, its specific principle will not be described in detail below.

[0041] Please see Figures 1 to 4 The present invention provides an embodiment:

[0042] A multi-angle positioning welding fixture is used for coaxial positioning and support of bimetallic composite pipes. It includes a support platform 1, on which external roller modules 2 are symmetrically installed. Double-end internal support modules 3 are symmetrically installed on the surface of the support platform 1. Each double-end internal support module 3 includes a sleeve 31. The sleeve 31 is inserted into the bimetallic composite pipe. A fixed telescopic end 32 and a movable telescopic end 33 are respectively installed on the surface of the sleeve 31. A central shaft 34 is slidably connected inside the sleeve 31. A drive module 35 is provided on the outside of the sleeve 31. The drive module 35 is used to drive the central shaft 34 to move and the sleeve 31 to rotate.

[0043] When the central shaft 34 moves along the sleeve 31 axially, it synchronously drives the fixed telescopic end 32 and the movable telescopic end 33 to extend radially and support the inner wall of the bimetallic composite pipe, thereby achieving high-precision coaxial positioning of the bimetallic composite pipe. The movable telescopic end 33 has radial elastic floating capability, which can synchronously retreat radially when the pipe expands and contracts due to the high temperature of welding, avoiding stress deformation or cracking of the inner layer due to rigid support.

[0044] During the welding process, the outer roller module 2 and the double-end inner support module 3 synchronously drive the bimetallic composite pipe to rotate, keeping the welding gun fixed, thus achieving synchronous welding of the circumferential seam at both ends of the pipe, improving welding accuracy and welding efficiency.

[0045] like Figure 5 As shown, the fixed telescopic end 32 includes several fixed grooves 321 formed on the surface of the sleeve 31. Each fixed groove 321 is slidably connected to a fixed inclined block 322. Each fixed inclined block 322 has a through-hole 1 on its surface. A fixed elastic element 323 is provided inside the through-hole 1. The movable telescopic end 33 includes several movable grooves 331 formed on the surface of the sleeve 31. Each movable groove 331 is slidably fitted with a movable element 332.

[0046] like Figure 5 As shown, several abutting inclined blocks 341 are fixedly connected to the surface of the central shaft 34. When the central shaft 34 moves axially along the inside of the sleeve 31, each abutting inclined block 341 abuts against the inclined surface of the corresponding fixed inclined block 322 and movable part 332 through the inclined surface, and simultaneously pushes the fixed inclined block 322 along the fixed groove 321 and the movable part 332 along the movable groove 331 to extend radially outward.

[0047] like Figure 5 and Figure 9 As shown, each movable component 332 includes an inclined shell 3321 and a movable abutment block 3322. The inclined shell 3321 and the movable abutment block 3322 are slidably fitted inside the movable groove 331, and the movable abutment block 3322 is slidably connected inside the inclined shell 3321. A synchronization hole 2 is provided through the surface of the movable abutment block 3322, and a number of movable elastic components 3323 are provided inside the synchronization holes 2.

[0048] like Figure 9 As shown, a reset elastic element 3324 is fixedly connected between the movable abutment block 3322 and the inclined shell 3321. The reset elastic element 3324 is used to realize the radial elastic floating function of the movable telescopic end 33.

[0049] It should be noted that when the central shaft 34 moves axially, the anti-clamping block 341 abuts against the inclined surface sleeve 3321 through the inclined surface, which drives the movable anti-clamping block 3322 to extend radially at the same time and abut against the inner wall of the inner layer of the bimetallic composite tube.

[0050] When the high temperature of welding causes the pipe to expand and contract, the movable contact block 3322 overcomes the elastic force of the reset elastic element 3324 and retracts radially along the inclined shell 3321 to avoid stress deformation or cracking of the inner layer due to rigid support. After welding is completed, the reset elastic element 3324 drives the movable contact block 3322 to automatically reset. The fixed telescopic end 32 is set away from the port of the bimetallic composite pipe, and the movable telescopic end 33 is set close to the port of the bimetallic composite pipe. The fixed telescopic end 32 is used to provide rigid positioning support for the bimetallic composite pipe at a position away from the weld, and the movable telescopic end 33 is used to provide elastic floating support for the bimetallic composite pipe at a position close to the weld to adapt to the thermal expansion and contraction deformation of the pipe port during welding.

[0051] like Figures 1 to 5 As shown, the drive module 35 includes a mounting plate 355 mounted on the support platform 1. A cylinder 354 is mounted on the mounting plate 355. The output shaft of the cylinder 354 is fixedly connected to the central shaft 34. A motor 353 is also mounted on the mounting plate 355. A gear 352 is hinged on the mounting plate 355. The output shaft of the motor 353 is connected to the gear 352 for transmission. Several teeth 351 are fixedly connected to the outer surface of the sleeve 31. The gear 352 meshes with the teeth 351 to drive the sleeve 31 to rotate synchronously.

[0052] like Figure 3 As shown, the tube bearing position formed by the outer roller module 2 is on the same axis as the axis of the sleeve 31, so that the sleeve 31 automatically maintains a coaxial state when inserted into the bimetallic composite tube.

[0053] It should be added that at least one of the two double-end inner support modules 3 can be slidably adjusted along the bearing platform 1; a guide rail is fixedly installed between the bearing platform 1 and the mounting plate 355, and the mounting plate 355 slides with the guide rail, which can drive the sleeve 31 to move laterally as a whole; when clamping the pipe, first slide the mounting plate 355 outward along the guide rail to make the two sleeves 31 move away from each other. After the bimetallic composite pipe is placed in place, push the mounting plate 355 back along the guide rail to make the sleeve 31 smoothly insert into the composite pipe, completing the clamping preparation. During the welding rotation, the rotation speed of the outer roller module 2 is consistent with the rotation speed of the sleeve 31. Both rotate synchronously at the same speed to ensure that the bimetallic composite tube rotates smoothly without relative slippage, misalignment or twisting, and to ensure uniform and stable circumferential welding. The fixed elastic element 323, the movable elastic element 3323, and the reset elastic element 3324 are all elastic reset components, including but not limited to compression springs, tension springs, elastic rubber columns, elastic ropes or polyurethane elastomers. The above elastic components can provide stable radial extension and resetting forces to ensure that the fixed inclined block 322 and the movable abutment block 3322 move smoothly and are reliably positioned during contraction and extension, while meeting the elastic avoidance requirements of the movable extension end 33 during welding thermal expansion and contraction.

[0054] Specifically, in the initial clamping stage, the operator first adjusts the double-end inner support module 3 on the bearing platform 1 according to the length specification of the bimetallic composite pipe. Since the mounting plate 355 on at least one side forms a sliding fit with the guide rail, the sleeve 31 on that side can be pulled outward so that the distance between the two sleeves 31 is greater than the length of the pipe, which makes it easier for the composite pipe to be placed stably on the outer roller module 2.

[0055] It should be noted that the pipe bearing position formed by the outer roller module 2 is kept on the same axis as the sleeve 31. This pre-concentric design allows the pipe to maintain a natural coaxial state with the sleeve 31 without manual alignment after placement, avoiding problems such as eccentricity and tilting from the clamping source, greatly reducing the difficulty of early debugging, and providing stable reference conditions for subsequent internal support.

[0056] After the pipe is placed in place, the mounting plate 355 on the sliding side is reset along the guide rail, so that the sleeves 31 on both sides are smoothly inserted into the inner ends of the bimetallic composite pipe.

[0057] At this time, the cylinder 354 in the drive module 35 starts, pushing the central shaft 34 to move axially along the inside of the sleeve 31. The abutting inclined block 341 on the surface of the central shaft 34 moves synchronously with the axial movement, and forms abutting engagement with the inclined surface at the bottom of the fixed inclined block 322 and the movable part 332 respectively through the inclined surface transmission method, converting the axial thrust into the radial driving force, pushing the fixed inclined block 322 along the fixed groove 321 and the movable part 332 along the movable groove 331 to extend outward synchronously until they are tightly supported against the inner wall of the composite pipe. This transmission method has uniform force and synchronous action, which can ensure that multiple sets of telescopic ends extend at the same time, avoiding pipe eccentricity caused by single point force or sequential extension, and further enhancing the coaxial positioning accuracy.

[0058] It should be noted that the inner wall of the bimetallic composite pipe is the core reference surface for achieving the coaxiality and welding accuracy of the entire pipe. Only by using the inner wall as the centering reference can we ensure that there are no problems such as eccentricity, misalignment, or uneven wall thickness during the welding of the inner and outer composite pipes. This fundamentally improves the quality of circumferential welds and structural strength. This device adopts a top support method with a single drive of the central shaft 34 and multiple sets of telescopic ends extending radially in sync. All fixed inclined blocks 322 and moving parts 332 are pushed synchronously by the abutting inclined blocks 341 on the same central shaft 34. There are no sequential actions, no individual drives, and no stroke deviations. This ensures that the inner wall is subjected to uniform force at 360° and synchronously tightened around the circumference. This ensures that the composite pipe is always in an absolutely centered state and avoids local overpressure that could cause deformation, scratches, or delamination of the inner layer. This truly achieves high-precision, damage-free coaxial centering.

[0059] Furthermore, the fixed telescopic end 32 and the movable telescopic end 33 adopt differentiated layouts and functional designs. Specifically, the fixed telescopic end 32 is located away from the pipe end and weld seam, relying on the fixed inclined block 322 and the fixed elastic element 323 to form a rigid support, providing a stable and non-deformable internal positioning foundation for the composite pipe, ensuring that the overall posture of the pipe does not shift, shake, or twist throughout the welding process. The movable telescopic end 33 is close to the pipe end and weld seam area, forming an elastic floating support structure through the inclined sleeve 3321, the movable abutment block 3322, and the reset elastic element 3324. This not only ensures effective support at the end but also provides space to avoid thermal expansion deformation caused by high welding temperatures, structurally solving the industry problem that traditional rigid internal supports easily lead to stress concentration, deformation, cracking, or even scrapping of the composite pipe's inner layer.

[0060] Once the welding operation begins, the temperature in the weld area rises rapidly, and the inner layer of the bimetallic composite pipe undergoes significant thermal expansion deformation due to the high temperature, causing the pipe diameter to expand instantaneously.

[0061] At this time, the movable contact block 3322 is subjected to radial pressure from the pipe wall, which overcomes the elastic force of the reset elastic element 3324. It makes a slight inward yield along the inclined sleeve 3321, automatically adapting to the expansion and change of the pipe diameter, avoiding damage to the pipe wall caused by the mutual compression of the rigid support and thermal expansion. When the welding is completed and the temperature drops, the pipe gradually shrinks and resets. The reset elastic element 3324 pushes the movable contact block 3322 to rebound outward in sync, always maintaining a close fit with the pipe wall and maintaining stable support. This dynamic following elastic yield mechanism can significantly improve the safety and yield of the welding process, especially suitable for the characteristics of bimetallic composite pipes with low inner layer strength and sensitivity to stress.

[0062] It should be added that the movable elastic element 3323 passes through the synchronous hole 2 of each movable abutment block 3322, forming a linkage constraint structure between multiple sets of movable abutment blocks 3322. During the process of the movable abutment block 3322 extending radially to tighten against the pipe wall, the movable elastic element 3323 is stretched synchronously, continuously accumulating elastic recoil force; when a movable abutment block 3322 at a certain position undergoes radial retraction due to the thermal expansion of the pipe, the elastic recoil force at that position will be synchronously transmitted to all other movable abutment blocks 3322 through the movable elastic element 3323, causing the other movable abutment blocks 3322 to synchronously produce a slight retraction, realizing linkage and equal amplitude elastic avoidance of full circumference expansion and contraction, avoiding uneven force and eccentric offset of the pipe caused by local single-point retraction. At the same time, the fixed expansion end 32 always maintains a rigid support state, providing a stable reference positioning for the composite pipe, ensuring that the overall coaxiality and posture of the pipe are not affected during the linkage retraction of the movable end, taking into account both thermal deformation adaptability and positioning stability, and further improving the reliability of the welding process.

[0063] During the welding rotation phase, the motor 353 in the drive module 35 starts, and through the meshing of the gear 352 and the teeth 351 on the surface of the sleeve 31, it drives the sleeve 31 to rotate at a uniform speed. The outer roller module 2 and the sleeve 31 maintain the same rotation speed, forming an internal and external synchronous drive structure, which together drive the bimetallic composite pipe to rotate smoothly. The outer roller provides stable external support and limit, while the internal telescopic end maintains synchronous rotation support. The internal and external cooperation prevents the pipe from slipping, misaligning, shifting, or twisting, ensuring that the pipe always rotates around the axis in a stable posture. At this time, the welding torch remains stationary, allowing for continuous, uniform, and complete welding of the circumferential seams at both ends of the pipe. The weld formation has high consistency, with no defects such as missed welds, off-center welds, or undercut, significantly improving welding quality and work efficiency.

[0064] Throughout the entire workflow, the fixed elastic element 323, the movable elastic element 3323, and the reset elastic element 3324 all play crucial roles. These elastic components can be constructed using compression springs, tension springs, elastic rubber columns, polyurethane elastomers, etc., ensuring stable reset of the telescopic end during contraction, smooth operation without jamming, and providing appropriate clamping and clearance forces, making the internal support both robust and without damaging the pipe wall. Simultaneously, the debris and impurities removed after cleaning do not affect the movement of the telescopic end, resulting in high long-term operational stability, low maintenance costs, and the ability to meet the needs of continuous batch production.

[0065] It should be added that this device can realize the synchronous welding operation of the circumferential seam at both ends of the bimetallic composite pipe through the synchronous linkage drive of the double-end inner support module 3 and the outer clamping roller module 2. The sleeves 31 on both sides maintain the same speed and rotate synchronously under the drive of the corresponding motors 353 and gears 352. The rotation speed of the outer clamping roller module 2 is perfectly matched with the rotation speed of the sleeves 31, so that the composite pipe rotates around the axis at a constant speed in a stable posture. The welding gun can be fixed at the weld position at both ends of the pipe. The continuous welding of the circumferential seam at both ends can be completed simultaneously without moving the welding gun, without secondary clamping, or without flipping the pipe.

[0066] This double-end synchronous welding method not only significantly shortens the welding operation cycle and improves production efficiency, but also ensures that the forming quality and welding parameters of the welds at both ends are completely consistent. It avoids the impact of the thermal deformation of the pipe after single-end welding on the welding accuracy of the other end, and fundamentally solves the problems of coaxiality deviation, poor weld consistency and low production efficiency in traditional step welding. It is especially suitable for the batch automated welding production needs of bimetallic composite pipes.

[0067] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A welding fixture for multi-angle positioning, used for coaxial positioning and support of bimetallic composite pipes, comprising a bearing platform (1), wherein external roller modules (2) are symmetrically mounted on the surface of the bearing platform (1), characterized in that: The surface of the bearing platform (1) is symmetrically equipped with double-end internal support modules (3). Each double-end internal support module (3) includes a sleeve (31). The sleeve (31) is inserted into the bimetallic composite tube. The surface of the sleeve (31) is respectively equipped with a fixed telescopic end (32) and a movable telescopic end (33). The inside of the sleeve (31) is slidably connected to a central shaft (34). The outside of the sleeve (31) is provided with a drive module (35). The drive module (35) is used to drive the central shaft (34) to move and the sleeve (31) to rotate. When the central shaft (34) moves axially along the sleeve (31), it synchronously drives the fixed telescopic end (32) and the movable telescopic end (33) to extend radially and support against the inner wall of the bimetallic composite tube. The movable telescopic end (33) has radial elastic floating capability. During the welding process, the outer roller module (2) and the double-end inner support module (3) synchronously drive the bimetallic composite pipe to rotate.

2. The welding fixture for multi-angle positioning according to claim 1, characterized in that: The fixed telescopic end (32) includes several fixed grooves (321) opened on the surface of the sleeve (31). Each fixed groove (321) is slidably connected with a fixed inclined block (322). Each fixed inclined block (322) has a through-hole opening on its surface. A fixed elastic element (323) is provided inside the through-hole. The movable telescopic end (33) includes several movable grooves (331) opened on the surface of the sleeve (31). Each movable groove (331) is slidably fitted with a movable element (332).

3. The welding fixture for multi-angle positioning according to claim 2, characterized in that: Several abutting inclined blocks (341) are fixedly connected to the surface of the central shaft (34). When the central shaft (34) moves axially along the inside of the sleeve (31), each abutting inclined block (341) abuts against the inclined surface of the corresponding fixed inclined block (322) and movable part (332) through the inclined surface, and simultaneously pushes the fixed inclined block (322) to extend radially outward along the fixed groove (321) and the movable part (332) along the movable groove (331).

4. The welding fixture for multi-angle positioning according to claim 3, characterized in that: Each of the movable components (332) includes a sloping shell (3321) and a movable abutment block (3322). The sloping shell (3321) and the movable abutment block (3322) are slidably fitted inside the movable groove (331), and the movable abutment block (3322) is slidably connected inside the sloping shell (3321). A second synchronization hole is provided through the surface of the movable abutment block (3322), and a number of the second synchronization holes are provided with movable elastic components (3323).

5. A welding fixture for multi-angle positioning according to claim 4, characterized in that: A reset elastic element (3324) is fixedly connected between the movable contact block (3322) and the inclined shell (3321). The reset elastic element (3324) is used to realize the radial elastic floating function of the movable telescopic end (33).

6. A welding fixture for multi-angle positioning according to claim 5, characterized in that: When the central shaft (34) moves axially, the abutting block (341) abuts against the inclined shell (3321) through the inclined surface, causing the movable abutting block (3322) to extend radially synchronously and abut against the inner wall of the bimetallic composite tube.

7. A welding fixture for multi-angle positioning according to any one of claims 1-6, characterized in that: The fixed telescopic end (32) is located away from the port of the bimetallic composite pipe, and the movable telescopic end (33) is located close to the port of the bimetallic composite pipe. The fixed telescopic end (32) is used to provide rigid positioning support for the bimetallic composite pipe at a position away from the weld, and the movable telescopic end (33) is used to provide elastic floating support for the bimetallic composite pipe at a position close to the weld.

8. A welding fixture for multi-angle positioning according to claim 1, characterized in that: The drive module (35) includes a mounting plate (355) mounted on the support platform (1), a cylinder (354) is mounted on the mounting plate (355), the output shaft of the cylinder (354) is fixedly connected to the central shaft (34), and a motor (353) is also mounted on the mounting plate (355).

9. A welding fixture for multi-angle positioning according to claim 8, characterized in that: A gear (352) is hinged on the mounting plate (355). The output shaft of the motor (353) is connected to the gear (352) for transmission. Several teeth (351) are fixedly connected to the outer surface of the sleeve (31). The gear (352) meshes with the teeth (351) to drive the sleeve (31) to rotate synchronously.

10. A welding fixture for multi-angle positioning according to claim 1, characterized in that: The pipe bearing position formed by the outer roller module (2) is on the same axis as the axis of the sleeve (31), so that the sleeve (31) automatically maintains a coaxial state when inserted into the bimetallic composite pipe.

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