Special fixture for robot welding pipeline flange displacement

Abstract

The invention discloses a robot welding pipeline flange displacement special clamp, and relates to the technical field of ship manufacturing equipment, the clamp comprises a processing table, a welding mechanical arm, a placing mechanism, two groups of pipeline clamping mechanisms, two groups of flange fixing mechanisms, a traction mechanism, a rotating platform and three screw rod sliding tables; the placing mechanism is slidably mounted in the middle of the machining table through the rotating platform, and the two pipeline clamping mechanisms are symmetrically slidably mounted on the two sides of the placing mechanism and can synchronously move and clamp pipelines. The two flange fixing mechanisms are symmetrically arranged on the two sides of the containing mechanism and horizontally move through a lead screw sliding table. The traction mechanism is connected with the machining table through a lead screw sliding table and can lock / unlock the rotating platform and drive the containing mechanism to move. The welding mechanical arm is in linkage with the clamp and can conduct welding along the butt joint axis. Multi-degree-of-freedom posture adjustment of a pipeline and a flange can be achieved, a straight pipe and a 0-90-degree bent pipe are matched, it is guaranteed that welding is in a horizontal butt joint state all the time, and the welding quality and efficiency are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shipbuilding equipment, in particular to a special fixture for robot welding of pipe flange displacement. BACKGROUND

[0002] In the field of shipbuilding, pipe flanges are the core connecting components of various pipeline systems (such as fuel, cooling, and ventilation systems), and their welding quality directly affects the operational safety and reliability of the ship. Due to the complex layout of ship pipelines, pipe flanges are usually large in size (diameter in the range of DN200-DN800) and need to withstand harsh working conditions such as high pressure, vibration, and seawater corrosion, so the sealing, strength, and forming precision of the welds are extremely high. Horizontal corresponding pipe flange welding is significantly different from other angle welding: when horizontally corresponding, the weld is in a horizontal plane, the gravity direction of the molten pool is perpendicular to the welding direction, the molten pool flowability is easier to control, the arc stability is high, the weld forming is uniform and the excess height is consistent; while welding at an inclined or vertical angle, the molten pool will deviate or sag due to gravity, which can easily lead to defects such as upper undercut and lower weld protrusions, and the welding torch needs to be frequently adjusted to adapt to the angle changes, increasing the difficulty of parameter control. Currently, the welding equipment for ship pipe flanges is mostly large fixed structure, mainly composed of three parts: first, a clamping mechanism for pipe fixation, which mostly adopts rigid jaw structure to achieve straight pipe positioning through radial clamping; second, a flange positioning seat, which achieves flange fixation through stop or bolt hole positioning; third, a welding robot, which automatically welds the connected pipe and flange based on a preset trajectory. This type of equipment can ensure the coaxiality of the pipe and flange (usually ≤0.5mm) through the cooperation of the clamping mechanism and the positioning seat when welding straight pipes and flanges, allowing the welding robot to complete the girth welding in a horizontal connection posture - in this state, the welding torch always maintains perpendicularity to the weld, and welding parameters such as current and voltage do not need to be adjusted due to angle changes, and the weld forming coefficient (width to depth ratio) can be stably controlled within the ideal range of 1.2-2.0; if in a non-horizontal angle, not only is the relative angle between the welding torch and the weld difficult to maintain constant, but the welding heat input distribution will also deviate due to gravity, resulting in significant fluctuations in weld strength and far less quality stability than horizontal corresponding welding.

[0003] However, the clamping mechanism and the flange positioning seat of the existing equipment are designed for straight pipe characteristics, lack of adaptability to bent pipes, and cannot simultaneously meet the welding requirements of straight pipes and bent pipes. When the welding object is a bent pipe and a flange, the limitation is particularly significant: because the bent pipe has a preset bending angle (such as 90°), after the non-bent end is fixed by the clamping mechanism, the spatial position of the bent end is difficult to naturally align with the fixed position of the flange positioning seat. At this time, the height or horizontal position of the flange positioning seat needs to be adjusted by mechanical structure, or the spatial posture of the pipe clamping end needs to be adjusted to realize the butt joint, but the relative posture of the pipe and the flange after adjustment will change from the ideal horizontal correspondence to an inclined or vertical correspondence. This posture deviation will cause the welding gun angle, arc voltage and walking trajectory of the welding robot to deviate from the optimal parameter range, easily causing defects such as weld edge misalignment, uneven penetration, and undercutting, which need to be repaired, not only reducing production efficiency, but also being difficult to meet the high-pressure sealing requirements of ship pipelines.

[0004] Therefore, in view of the welding requirements of the pipeline flange for ships, a special fixture for adjusting the relative posture of the pipeline and the flange is needed to adapt to the combination of straight pipes, pipes with different bending angles and pipes with different specifications and flanges, to ensure that the welding process is always in the optimal spatial posture, thereby improving the welding quality and efficiency. SUMMARY

[0005] Therefore, in view of the welding requirements of the pipeline flange for ships, a special fixture for adjusting the relative posture of the pipeline and the flange is needed to adapt to the combination of straight pipes, pipes with different bending angles and pipes with different specifications and flanges, to ensure that the welding process is always in the optimal spatial posture, thereby improving the welding quality and efficiency. The processing table is a horizontal bearing base, and the placement mechanism is slidably installed on the upper part of the middle part through the rotating platform, and the flange fixing mechanism is symmetrically arranged on both sides, and the traction mechanism is arranged on one side; The rotating platform is provided with a long strip-shaped assembly groove at the upper end, and the placement mechanism is embedded in the assembly groove through the bottom limiting structure, which can realize 0-180° rotation with the rotating platform to switch the horizontal / vertical posture, and can also slide along the assembly groove to fine-tune the horizontal position; one side of the rotating platform is provided with a positioning hole matched with the bottom positioning plate of the traction mechanism, which can limit the accidental rotation of the rotating platform through mechanical locking, or can be unlocked to meet the posture adjustment requirement; The placement mechanism includes a placement rack and a butt joint rack: the placement rack is internally provided with a double-shaft motor and symmetrically distributed threaded rods, the double-shaft motor can drive the threaded rods to rotate synchronously, the two groups of pipe clamping mechanisms are driven by the moving connection structure to move horizontally along the placement rack, and the distance between the pipe and the flange is adjusted; the butt joint rack is composed of a connecting plate and a butt joint block, and can be detachably connected with the traction mechanism, and driven by the traction mechanism to slide along the assembly groove of the rotating platform to complete the fine adjustment of the posture; The pipeline clamping mechanism is symmetrically arranged on both sides of the placing rack, and each group comprises a connecting piece, a fixing piece and a driving piece; the support frame of the connecting piece is provided with a support rotating wheel to support the bottom of the pipeline, and the rotating limiting frame of the fixing piece is provided with two limiting rotating wheels to symmetrically limit from both sides, and the center lines of the three rotating wheels form an equilateral triangle to form a three-point flexible clamping structure; the driving piece is connected with the closed transmission chain through a transmission sprocket, and can drive the support rotating wheel and the limiting rotating wheel to synchronously rotate in the same direction, the rotating precision is ≤0.1°, and the pipeline is driven to rotate at a uniform speed to adapt to the welding requirement; The flange fixing mechanism moves horizontally through a lead screw sliding table, and each group comprises a sliding base, a driving source and a pneumatic clamping device; the sliding base moves along the machining table under the driving of the lead screw sliding table, and the relative position of the flange and the pipeline is adjusted; the pneumatic clamping device adopts a three-jaw elastic structure, the clamping jaw surface is provided with a sawtooth-shaped rubber anti-skid pattern, the friction coefficient is ≥0.6, the clamping force can be adjusted in the range of 5-10kN, the flange can be stably fixed, and the surface of the flange is also prevented from being damaged; the driving source can drive the pneumatic clamping device to rotate around the mounting plate, so that the flange sealing surface and the pipeline end surface are kept parallel, and the butt joint adhesion is ensured; The traction mechanism moves forward and backward through a lead screw sliding table, and the traction frame is provided with a penetrating slot and a butt joint slot, which can be respectively embedded with the connecting plate and the butt joint block of the placing mechanism, to form a transmission connection to drive the placing mechanism to slide; at the same time, the traction mechanism can be embedded into the rotating platform positioning hole through the bottom positioning plate, and the rotating platform is locked to ensure the posture stability during straight pipe welding; The three lead screw sliding tables work in cooperation: two of them drive the flange fixing mechanisms on both sides to move horizontally, and accurately align the pipeline port; the third one drives the traction mechanism to realize the locking / unlocking of the rotating platform and the sliding driving of the placing mechanism; the welding mechanical arm is a six-axis or more type, which can obtain the spatial position of the pipeline and the flange in real time through a 3D visual identification system, the identification accuracy is ≤0.5mm, the welding gun posture is adjusted according to the identification data, the posture adjustment accuracy is ≤0.5mm, and the welding operation is completed along the butt joint axis of the pipeline and the flange.

[0006] By adopting the above technical scheme, the collaborative displacement of the rotating platform and the traction mechanism breaks through the limitation of traditional equipment that is only suitable for straight pipes: When welding a bent pipe, the rotating platform is unlocked by the traction mechanism, the placing mechanism is driven by the rotating platform to rotate from horizontal to vertical to adapt to the spatial angle of the bent pipe, and then the position of the placing mechanism is fine-tuned through the transmission cooperation of the traction mechanism and the butt joint frame, so that the bent pipe curved end is accurately aligned with the flange; When welding a straight pipe, the rotating platform is locked by the traction mechanism, the placing mechanism drives the two sets of pipeline clamping mechanisms to move synchronously, and cooperates with the flange fixing mechanisms on both sides to realize the simultaneous butt joint of the flanges at both ends of the straight pipe, without the need for repeated clamping; Finally, the compatible welding of straight pipes and 0-90° bent pipes is realized, and the posture adaptation and efficiency bottleneck of multiple types of pipeline welding are solved.

[0007] Furthermore, the top of the connector of the pipe clamping mechanism is provided with a micro motor, which can drive the rotating connection structure to cause the fixing part to swing around the pipe axis; By adopting the above technical solution, the clamping position of the limiting wheel can be adjusted according to the bending angle of the pipe (0-90°), so that both the non-bent end and the bent end of the pipe can be stably positioned. It is suitable for straight pipes of different diameters (DN200-DN800) and compatible with multi-angle bends, while avoiding damage to the pipe surface caused by rigid clamping.

[0008] Furthermore, the transmission chain of the drive component is doubly limited by a drive mounting frame and a fixed limiting frame. The drive mounting frame is arranged around the transmission chain, and the fixed limiting frame restricts the chain trajectory. By adopting the above technical solution, the connection wrap angle between the transmission chain and the transmission sprocket can be ensured to be ≥180°, effectively preventing chain slippage, ensuring that the support wheel and the limit wheel rotate synchronously, making the pipeline rotate smoothly, avoiding the displacement of the molten pool due to uneven rotation, and ensuring the quality of weld formation.

[0009] Furthermore, the motion control system of the welding robot arm is linked with each mechanism of the fixture, and the welding current is monitored in real time during the welding process to control the current fluctuation to ≤±2%; By adopting the above technical solution and combining it with the real-time position feedback of the 3D vision recognition system, the welding torch posture and welding parameters can be dynamically compensated to ensure the stability of the welding process, further reduce the weld defect rate, and meet the stringent requirements of high-pressure sealing of ship pipeline flanges.

[0010] In summary, the present invention has the following main beneficial effects: 1. This invention utilizes the sliding cooperation between a rotating platform and a placement mechanism (the bottom limiting block of the placement mechanism is embedded in the elongated assembly slot of the rotating platform). The rotating platform can drive the placement mechanism to rotate from 0 to 180°, providing a basis for adjusting the posture of the bent pipe from the lateral to the longitudinal direction. The detachable connection between the traction mechanism and the placement mechanism (the through slot of the traction frame accommodates the connecting plate of the placement frame, and the bottom docking slot is embedded with the docking block) and the screw slide table drives the traction mechanism to move back and forth, which can further drive the placement mechanism to slide along the assembly slot of the rotating platform, precisely fine-tuning the spatial position of the pipe. At the same time, the pipe clamping mechanism forms a three-point flexible clamping structure through "supporting rotating wheel + two limiting rotating wheels" (the center line of the three rotating wheels is an equilateral triangle). The micro motor drives the rotating connecting rod to drive the rotating limiting frame to swing, which can make the limiting rotating wheel approach or move away from the pipe. It can stably clamp straight pipes of different diameters and adapt to bent pipes with bending angles of 0-90°, completely solving the limitation of traditional equipment that is only designed for straight pipes. 2、In the application, the coaxiality cooperation of the flange fixing mechanism and the pipeline clamping mechanism (the posture of the pneumatic clamping device of the flange fixing mechanism is adjusted by the driving source to make the flange sealing surface parallel to the pipeline end surface, and the positioning precision of the cooperation of the pipeline clamping mechanism is ≤0.5mm), ensures that there is no deviation when the pipeline and the flange are docked; the locking cooperation of the rotating platform and the traction mechanism (the bottom positioning plate of the traction mechanism is embedded into the circular positioning opening of the rotating platform), the rotating platform can be locked when the straight pipe is welded, and the accidental rotation of the pipeline is avoided to prevent the welding gun angle from deviating; the synchronous rotation cooperation of the pipeline clamping mechanism (the driving part drives the support rotating wheel and the limiting rotating wheel to rotate synchronously and in the same direction through the transmission sprocket and the transmission chain, and the rotation precision is ≤0.1°), can drive the pipeline to rotate at a constant speed, so that the welding mechanical arm always moves along the horizontal docking weld seam axis, avoids the molten pool from deviating due to gravity to cause undercutting, welding tumor and other defects, and ensures that the weld forming coefficient is stably in the ideal range of 1.2-2.0.

[0011] 3、In the application, the symmetric cooperation of the two groups of flange fixing mechanisms (horizontally corresponding arrangement along the two sides of the placing mechanism, respectively connected with the machining table through the screw rod sliding table), the two ends can be simultaneously docked with the flanges when the straight pipe is welded, the welding mechanical arm can quickly switch to the other end welding after completing the welding of one end without the need for re-adjusting the equipment, and the efficiency is more than 3 times higher than that of the traditional single station; when the elbow pipe is welded, the unlocking cooperation of the traction mechanism and the rotating platform (the screw rod sliding table drives the traction mechanism to move backward, and the bottom positioning plate is separated from the positioning opening of the rotating platform), the rotating platform can quickly drive the placing mechanism to rotate from horizontal to vertical, and the docking transmission of the traction mechanism and the placing mechanism can complete the posture adjustment of the elbow pipe in only 1-2 minutes, which is much faster than the mechanical adjustment mode of the traditional equipment; in addition, the transmission cooperation of the double-shaft motor, the threaded rod and the moving connecting frame in the placing mechanism (the double-shaft motor drives the two threaded rods to rotate synchronously, and drives the moving connecting frame to move horizontally along the limiting rod), can make the two groups of pipeline clamping mechanisms approach or move away synchronously, quickly align the center of the flange, and shorten the clamping time.

[0012] 4、In the application, the three-point flexible clamping cooperation of the pipeline clamping (the support rotating wheel supports the bottom of the pipeline, the two limiting rotating wheels limit from both sides, and the three rotating wheels are distributed in an equilateral triangle), can avoid damage to the surface of the pipeline caused by rigid clamping, and prevent the pipeline from shaking during welding; the anti-slip cooperation of the flange fixing (the pneumatic clamping device adopts a three-jaw structure, the surface of the clamping jaw is provided with sawtooth-shaped rubber anti-slip lines, the friction coefficient is ≥0.6, and the clamping force range is 5-10kN), can firmly fix the flange to avoid deviation of the flange due to vibration during welding; the anti-slip cooperation of the transmission system (the driving part is arranged around the transmission chain through the driving mounting frame, and the fixed limiting frame limits the chain track, ensures that the connection included angle between the transmission chain and the side end transmission sprocket of the support frame is ≥180°), can prevent the transmission of the sprocket and chain from slipping, ensure the synchronous rotation of the support rotating wheel and the limiting rotating wheel, and further improve the stability of the pipeline rotation. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 This is a three-dimensional illustration of the present invention. Figure 1 ; Figure 2 This is a three-dimensional illustration of the present invention. Figure 2 ; Figure 3 In this invention Figure 2 Enlarged view of point A; Figure 4 This is a schematic diagram of the assembly of the placement mechanism and the rotating platform in this invention; Figure 5 This is a schematic diagram of the internal structure of the placement mechanism in this invention; Figure 6 This is a three-dimensional schematic diagram of the pipe clamping mechanism in this invention. Figure 1 ; Figure 7 This is a schematic diagram showing the disassembled pipe clamping mechanism in this invention; Figure 8 This is a three-dimensional schematic diagram of the pipe clamping mechanism in this invention. Figure 2 ; Figure 9 This is a three-dimensional schematic diagram of the flange fixing mechanism in this invention; Figure 10 This is a three-dimensional schematic diagram of the traction mechanism in this invention.

[0014] In the diagram: 1. Processing table; 2. Welding robotic arm; 3. Placement mechanism; 11. Rotary platform; 12. Screw slide; 121. Assembly slot; 122. Positioning opening; 31. Placement rack; 32. Assembly block; 33. Limiting block; 34. Partition plate; 35. Dual-axis motor; 36. Threaded rod; 37. Limiting rod; 38. Moving connecting frame; 39. Docking frame; 391. Connecting plate; 393. Docking block; 4. Pipe clamping mechanism; 41. Connecting component; 411. Sliding mounting frame; 412. Support frame; 413. Support wheel; 414. Inclined connection 415. Frame; 416. Rotating connecting rod; 42. Micro motor; 43. Fixing component; 44. Rotating limit frame; 45. Rotating connecting block; 46. Limiting wheel; 47. Driving component; 48. Transmission sprocket; 49. Transmission chain; 40. Drive mounting frame; 41. Drive power supply; 42. Fixed limit frame; 5. Flange fixing mechanism; 51. Sliding base; 52. Mounting plate; 53. Drive source; 54. Pneumatic clamping device; 6. Traction mechanism; 61. Traction frame; 612. Through slot; 613. Docking slot; 64. Bottom positioning plate. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0016] The embodiments of the present invention will now be described.

[0017] Example 1 See attached document Figures 1-10 The illustrated robotic welding pipe flange displacement fixture includes a processing table 1, a welding robotic arm 2, a placement mechanism 3, two sets of pipe clamping mechanisms 4, two sets of flange fixing mechanisms 5, a traction mechanism 6, a rotating platform 11, and three lead screw slides 12. The connection relationships, positional relationships, and functions of each component are as follows: Overall layout and core connections The processing table 1 is a horizontal bearing base. A placement mechanism 3 is slidably installed on the upper part of the middle. A rotating platform 11 is provided below the placement mechanism 3. The placement mechanism 3 is slidably engaged with the assembly groove 121 at the upper end of the rotating platform 11 through the bottom limiting block 33. The rotating platform 11 can drive the placement mechanism 3 to rotate from 0 to 180°. At the same time, the placement mechanism 3 can slide along the assembly groove 121 on the rotating platform 11. Two sets of pipe clamping mechanisms 4 are symmetrically slidably installed on the left and right sides of the placement mechanism 3. The two sets of pipe clamping mechanisms 4 can move horizontally synchronously under the drive of the placement mechanism 3 to clamp straight pipes or bends. Two sets of flange fixing mechanisms 5 are symmetrically arranged on both sides of the processing table 1. Both sets of flange fixing mechanisms 5 are horizontally corresponding to the placement mechanism 3, and are respectively connected to the processing table 1 through two screw slides 12. The screw slides 12 can drive the flange fixing mechanisms 5 to move horizontally along the processing table 1. A traction mechanism 6 is provided on one side of the processing table 1. The traction mechanism 6 is connected to the processing table 1 through a third screw slide 12. The screw slide 12 can drive the traction mechanism 6 to move back and forth. The traction mechanism 6 cooperates with the positioning opening 122 on one side of the rotating platform 11 through the bottom positioning plate 62 to realize the locking or unlocking of the rotating platform 11. The welding robotic arm 2 is a six-axis or higher robotic arm, located next to the processing table 1. Its motion control system is linked with the fixture, and it can move and weld along the connection axis between the pipe and the flange.

[0018] Structure and function of rotating platform 11 The upper end of the rotating platform 11 is provided with a long strip-shaped assembly groove 121. The length direction of the assembly groove 121 is consistent with the sliding direction of the placement mechanism 3, and is used to guide the sliding of the placement mechanism 3. The rotating platform 11 has a positioning opening 122 on the side near the traction mechanism 6. The positioning opening 122 is a circular hole. When the traction mechanism 6 is not connected to the placement mechanism 3, the bottom positioning plate 62 of the traction mechanism 6 can be inserted into the positioning opening 122 to mechanically lock and restrict the rotating platform 11 from rotating accidentally. When the rotating platform 11 needs to work, the lead screw slide 12 drives the traction mechanism 6 to move backward, so that the bottom positioning plate 62 is disengaged from the positioning opening 122, thereby releasing the restriction on the rotating platform 11.

[0019] Structure and function of placement mechanism 3 The placement mechanism 3 includes a placement rack 31 and a docking rack 39: The placement rack 31 has a rectangular frame structure, with a long strip-shaped assembly block 32 at its top. The assembly block 32 is slidably engaged with the pipe clamping mechanism 4 to limit the sliding trajectory of the pipe clamping mechanism 4. The bottom of the placement rack 31 is provided with a limiting block 33 that is adapted to the assembly groove 121 to achieve a sliding connection with the rotating platform 11. The placement rack 31 has two symmetrical partition plates 34 inside, and a dual-axis motor 35 is fixedly installed between the two partition plates 34. Each partition plate 34 is provided with a threaded rod 36 and two limiting rods 37 between it and the inner wall of the placement rack 31. The threaded rod 36 and the limiting rods 37 are rotatably installed between the partition plate 34 and the inner wall of the placement rack 31, and the two limiting rods 37 are symmetrically distributed on both sides of the threaded rod 36. The inner ends of the two threaded rods 36 are coaxially fixed to the two output ends of the dual-axis motor 35, and the outer ends are threadedly connected to the movable connecting frame 38. The movable connecting frame 38 slides with the two limiting rods 37. The top of the movable connecting frame 38 is fixedly connected to the pipe clamping mechanism 4. When the dual-axis motor 35 drives the threaded rod 36 to rotate, it can drive the movable connecting frame 38 to move horizontally along the limiting rods 37, thereby realizing the synchronous approach or departure of the two sets of pipe clamping mechanisms 4. The docking frame 39 is fixedly installed on the side of the placement frame 31 near the traction mechanism 6, and consists of a connecting plate 391 and a docking block 393. The connecting plate 391 is a rectangular horizontal plate, one end of which is fixed to the side wall of the placement frame 31, and the other end is vertically fixed to the docking block 393 (rectangular vertical plate). When the placement frame 31 rotates with the rotating platform 11 to the longitudinal direction, the connecting plate 391 can be inserted into the through slot 611 of the traction mechanism 6, and the docking block 393 is embedded in the docking groove 612 of the traction mechanism 6. When the traction mechanism 6 moves, it can drive the placement frame 31 to slide along the assembly groove 121 of the rotating platform 11 through the docking frame 39.

[0020] Structure and function of pipe clamping mechanism 4 Each set of pipe clamping mechanisms 4 includes a connector 41, a fixing member 42, and a driving member 43: The connector 41 includes a sliding mounting frame 411, a support frame 412, a support wheel 413, and two inclined connecting frames 414. The sliding mounting frame 411 is a rectangular plate, with its bottom end fixed to the movable connecting frame 38 and its top end slidingly engaged with the assembly block 32 of the placement frame 31. The support frame 412 is vertically fixed to the middle of the top of the sliding mounting frame 411, and the support wheel 413 is rotatably mounted on the top of the support frame 412 to support the bottom of the pipe. The two inclined connecting frames 414 are symmetrically fixed on both sides of the top of the sliding mounting frame 411 and are inclined towards the center of the pipe. Each inclined connecting frame 414 has a rotating connecting rod 415 rotatably mounted on its top end. One end of the rotating connecting rod 415 is fixed to the output end of the micro motor 416 (the micro motor 416 is fixed to one side of the top of the inclined connecting frame 414). The micro motor 416 can drive the rotating connecting rod 415 to rotate around its own axis. The fixing component 42 includes two rotating limit frames 421, two rotating connecting blocks 422, and two limiting wheels 423; its bottom end is fixed to the rotating connecting rod 415 through the rotating connecting block 422, and the limiting wheel 423 is rotatably installed at the top end; when the rotating connecting rod 415 rotates, it can drive the rotating limit frame 421 to swing, so that the two limiting wheels 423 move closer to or away from the pipeline, and form a three-point flexible clamping structure with the supporting wheel 413 (the line connecting the centers of the three wheels is an equilateral triangle). The driving component 43 includes three transmission sprockets 431, a transmission chain 432, a driving mounting bracket 433, a driving power supply 434, and two fixed limiting brackets 435. The three transmission sprockets 431 are respectively fixed to the side ends of the support frame 412 and the two rotating limiting brackets 421, and are coaxial with the rotating shafts of the support wheel 413 and the limiting wheel 423. The transmission chain 432 is sleeved on the three transmission sprockets 431 to form a closed transmission. The driving mounting bracket 433 is fixed to one side of the sliding mounting bracket 411 and is arranged around the transmission chain 432 for... The connection wrap angle between the transmission chain 432 and the transmission sprocket 431 on the side of the support frame 412 is increased to ≥180°; the drive power supply 434 is fixed on the drive mounting frame 433, and its output end is connected to the transmission sprocket 431 on the side of the support frame 412, which can drive the transmission sprocket 431 to rotate, and then drive the other two transmission sprockets 431 to rotate synchronously through the transmission chain 432, so as to realize the synchronous rotation of the support wheel 413 and the two limit wheels 423 in the same direction (rotation accuracy ≤0.1°), and drive the pipe to rotate to adapt to the welding requirements.

[0021] Structure and function of flange fixing mechanism 5 Each flange fixing mechanism 5 includes a sliding base 51, a mounting plate 52, a drive source 53, and a pneumatic clamping device 54. The sliding base 51 is a rectangular slider that is slidably installed in the guide rail of the processing table 1. Its bottom end is fixed to the working end of the lead screw slide 12. The lead screw slide 12 can drive the sliding base 51 to move horizontally along the processing table 1. Mounting plate 52 is vertically fixed to the top of sliding base 51. Drive source 53 and pneumatic clamping device 54 are rotatably mounted on both sides of it, and the output end of drive source 53 is fixed to the rotating shaft of pneumatic clamping device 54. Drive source 53 can drive pneumatic clamping device 54 to rotate around mounting plate 52. The pneumatic clamping device 54 has a three-jaw structure. The surface of the jaws is provided with serrated rubber anti-slip texture (friction coefficient ≥0.6). It can be clamped or released by air pressure. The clamping force range is 5-10kN and the repeatability is ≤0.1mm. It is used to fix the flange and ensure the coaxiality of the flange and the pipeline.

[0022] Structure and function of traction mechanism 6 The traction mechanism 6 includes a traction frame 61 and a bottom positioning plate 62. The traction frame 61 is a rectangular frame that is slidably installed in the guide rail of the processing table 1, and its bottom end is fixed to the working end of the lead screw slide table 12. The traction frame 61 has a through slot 611 (for accommodating the connecting plate 391) on the side near the placement mechanism 3, and a docking slot 612 (for embedding the docking block 393) is provided at the bottom of the through slot 611. The bottom positioning plate 62 is vertically fixed to the bottom end of the traction frame 61. Its size is adapted to the positioning opening 122 of the rotating platform 11 and is used to lock or unlock the rotating platform 11.

[0023] Working principle: Welding operations between straight pipes and flanges Initial preparation: Start the equipment. The lead screw slide 12 drives the traction mechanism 6 to move forward, so that the bottom positioning plate 62 is embedded into the positioning opening 122 of the rotating platform 11, and the rotating platform 11 is locked. At this time, the rotating platform 11 is in a horizontal state. Place the straight pipe to be welded on the support rollers 413 of the two sets of pipe clamping mechanisms 4. Start the micro motor 416 to drive the rotating connecting rod 415 to drive the rotating limit frame 421 to swing, so that the two limit rollers 423 approach the straight pipe and cooperate with the support rollers 413 to clamp the straight pipe (positioning accuracy ≤0.5mm). Install the two flanges on the pneumatic clamping devices 54 of the two sets of flange fixing mechanisms 5 respectively. Start the drive source 53 to adjust the flange posture so that the flange sealing surface is parallel to the end face of the straight pipe.

[0024] Position adjustment: Start the dual-axis motor 35 of the placement mechanism 3 to drive the threaded rod 36 to rotate, which in turn drives the movable connecting frame 38 and the two sets of pipe clamping mechanisms 4 to move synchronously, so that the two ends of the straight pipe are aligned with the center of the two sets of flanges respectively; start the two screw slides 12 of the connecting flange fixing mechanism 5 to drive the two sets of flange fixing mechanisms 5 to move closer to the straight pipe until the end face of the straight pipe is in contact with the flange sealing surface (gap ≤ 0.2mm), and then close the screw slides 12.

[0025] Welding operation: Start the drive power supply 434 of the welding robotic arm 2 and the pipe clamping mechanism 4; the drive power supply 434 drives the support wheel 413 and the limit wheel 423 to rotate synchronously through the transmission sprocket 431 and the transmission chain 432, thereby driving the straight pipe to rotate at a uniform speed (the speed is set according to the welding parameters); the welding robotic arm 2 obtains the docking position of the straight pipe and the flange in real time through the vision recognition system, moves the welding torch along the docking axis, and completes the circumferential weld of one end of the flange according to the preset parameters (current, voltage); after the welding of one end is completed, the welding robotic arm 2 moves to the other end of the straight pipe and repeats the above process to complete the welding of the other end of the flange; during the welding process, the pneumatic clamping device 54 maintains a clamping force of 5-10kN to prevent the flange from shifting.

[0026] Operation completed: After welding is completed, turn off the drive power 434 and welding robot arm 2, start the pneumatic clamping device 54 to release the flange, start the micro motor 416 to move the limit wheel 423 away from the straight pipe, take out the welded straight pipe flange assembly, and reset the equipment.

[0027] Example 2 Welding operation between 90° bend and flange (main welding method) Initial preparation: Start the lead screw slide 12 to drive the traction mechanism 6 to move backward, so that the bottom positioning plate 62 disengages from the positioning opening 122 of the rotating platform 11, and releases the lock of the rotating platform 11; place the 90° bend on the support rollers 413 of the two sets of pipe clamping mechanisms 4, so that the non-bent end of the bend is close to one set of flange fixing mechanisms 5, and the bent end is facing the other set of flange fixing mechanisms 5; start the micro motor 416 so that the limit roller 423 cooperates with the support roller 413 to clamp the bend.

[0028] Posture adjustment: Start the rotating platform 11 to drive the placement mechanism 3 and the bend to rotate from the horizontal to the vertical (rotation angle 90°); start the lead screw slide 12 connected to the traction mechanism 6 to drive the traction mechanism 6 to move forward, so that the connecting plate 391 of the placement mechanism 3 is inserted into the through slot 611 of the traction frame 61, and the docking block 393 is embedded in the docking groove 612; start the lead screw slide 12 of the traction mechanism 6 to drive the traction frame 61 to drive the placement mechanism 3 to slide along the assembly groove 121 of the rotating platform 11, so that the bent end of the bend is aligned with the center of the flange; start the lead screw slide 12 of the corresponding flange fixing mechanism 5 to drive the flange to approach the bent end of the bend until they fit together.

[0029] Welding operation: Start the drive power supply 434 of the welding robot arm 2 and the pipe clamping mechanism 4; the drive power supply 434 drives the bent pipe to rotate at a constant speed, and the welding robot arm 2 completes the circumferential weld along the docking axis between the bent end and the flange; during the welding process, the traction mechanism 6 remains stationary to prevent the placement mechanism 3 from sliding.

[0030] Alternative welding method (when the main method cannot complete the full circumference welding): If there is a welding blind zone at the joint between the bent end of the pipe and the flange, and the welding robot arm 2 can only complete the upper half of the circumference welding, then: After the upper half of the circumference is welded, turn off the drive power supply 434, start the pneumatic clamping device 54 to release the flange, start the drive power supply 434 of the pipe clamping mechanism 4, and drive the bend and the flange to rotate 180° synchronously, so that the unwelded lower half of the circumference faces upward. Start the screw slide 12 connected to another set of flange fixing mechanisms 5, drive the flange fixing mechanism 5 to move closer to the flange, start the pneumatic clamping device 54 to clamp the flange; start the pneumatic clamping device 54 of the original flange fixing mechanism 5 to release the flange, start the traction mechanism 6 to drive the placement mechanism 3 to make fine adjustments, and ensure that the flange is aligned with the bend. Start the welding robotic arm 2 and drive power supply 434 to complete the second half of the welding cycle. The subsequent steps are the same as the operation completion stage in Example 1.

[0031] Although embodiments of the present invention have been shown and described, these specific embodiments are merely explanations of the invention and are not intended to limit it. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions, and variations to the embodiments as needed without departing from the principles and spirit of the invention, but such modifications, substitutions, and variations are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A special fixture for robotic welding of pipe flange displacement, characterized in that, It includes a processing table (1), a welding robotic arm (2), a placement mechanism (3), two sets of pipe clamping mechanisms (4), two sets of flange fixing mechanisms (5), a traction mechanism (6), a rotating platform (11), and three screw slides (12). The placement mechanism (3) is slidably mounted on the middle of the processing table (1) via the rotating platform (11), and the pipe clamping mechanism (4) is symmetrically slidably mounted on both sides of the placement mechanism (3) and driven by it to move synchronously. The flange fixing mechanism (5) is symmetrically arranged on both sides of the placement mechanism (3) and moves horizontally through the screw slide (12). The traction mechanism (6) is connected to the placement mechanism (3) through another screw slide (12) to form a multi-degree-of-freedom displacement system.

2. The robotic welding pipe flange displacement fixture according to claim 1, characterized in that, The rotating platform (11) has an assembly slot (121) at its upper end. The placement mechanism (3) slides with the assembly slot (121) through a bottom limiting block (33). The rotating platform (11) has a positioning hole (122) on one side. The bottom positioning plate (62) of the traction mechanism (6) can be embedded in the positioning hole (122) to restrict the accidental rotation of the rotating platform (11) through mechanical locking.

3. The special fixture for robot welding pipe flange displacement according to claim 1, characterized in that, The placement mechanism (3) includes a placement rack (31) and a docking rack (39): The placement frame (31) is equipped with a dual-axis motor (35) and symmetrically distributed threaded rods (36). The dual-axis motor (35) drives the threaded rods (36) to rotate synchronously, and the pipe clamping mechanism (4) is driven to move horizontally along the placement frame (31) through the movable connecting frame (38). The docking frame (39) is detachably connected to the traction mechanism (6) via a connecting plate (391) and a docking block (393) to realize the longitudinal movement and angle adjustment of the placement mechanism (3).

4. A special fixture for robot welding pipe flange displacement according to claim 1, characterized in that, Each of the pipe clamping mechanisms (4) includes a connector (41), a fixing member (42), and a driving member (43): The support wheel (413) is installed on the support frame (412) of the connector (41), and the limiting wheel (423) is installed on the rotation limiting frame (421) of the fixing member (42). The support wheel (413) and the limiting wheel (423) form a three-point flexible clamping structure, and the center line of the three wheels forms an equilateral triangle. The driving component (43) drives the supporting wheel (413) and the limiting wheel (423) to rotate synchronously and in the same direction through the transmission sprocket (431) and the transmission chain (432), with a rotation accuracy of ≤0.1°.

5. A special fixture for robot welding pipe flange displacement according to claim 4, characterized in that, The top of the inclined connecting frame (414) of the connector (41) is equipped with a micro motor (416). The micro motor (416) drives the rotating connecting rod (415) to drive the fixing member (42) to rotate around the pipe axis, thereby realizing the posture adjustment of the pipe clamping mechanism (4) to adapt to pipes with bending angles of 0-90°.

6. A special fixture for robot welding pipe flange displacement according to claim 1, characterized in that, Each flange fixing mechanism (5) includes a sliding base (51), a pneumatic clamping device (54), and a drive source (53): The sliding base (51) is driven to move horizontally by the lead screw slide (12). The pneumatic clamping device (54) adopts an elastic claw structure. The claw surface is provided with serrated rubber anti-slip texture, the friction coefficient is ≥0.6, and the clamping force range is 5-10kN. The pneumatic clamping device (54) achieves rapid clamping and release of the flange through the drive source (53), with a repeatability accuracy of ≤0.1mm.

7. A special fixture for robot welding pipe flange displacement according to claim 1, characterized in that, The traction frame (61) of the traction mechanism (6) has a through slot (611) and a docking slot (612). The connecting plate (391) and docking block (393) of the docking frame (39) can be embedded in the through slot (611) and the docking slot (612) respectively. The traction frame (61) is driven to move by the lead screw slide (12), which drives the placement mechanism (3) to achieve ±180° rotation and longitudinal displacement on the rotating platform (11).

8. A special fixture for robot welding pipe flange displacement according to claim 1, characterized in that, The driving power supply (434) of the driving component (43) drives the support wheel (413) and the limiting wheel (423) to rotate synchronously through the transmission sprocket (431) and the transmission chain (432). The transmission chain (432) is limited by the driving mounting bracket (433) and the fixed limiting bracket (435) to ensure that the transmission wrap angle is ≥180° and to prevent the chain from slipping.

9. A special fixture for robot welding pipe flange displacement according to claim 1, characterized in that, The welding robotic arm (2) is a six-axis or higher robotic arm, and it is linked with the motion control system of the fixture through a vision recognition system: The visual recognition system uses a 3D industrial camera with a recognition accuracy of ≤0.5mm to acquire the spatial position of pipes and flanges in real time. The robotic arm adjusts the welding torch posture based on the recognition data, with a posture adjustment accuracy of ≤0.5° and welding current fluctuation of ≤±2%.

10. A special fixture for robot welding pipe flange displacement according to claim 1, characterized in that, The key load-bearing components of the rotating platform (11), the placement mechanism (3) and the pipe clamping mechanism (4) are made of aluminum alloy, which reduces the overall weight while ensuring structural strength; the surfaces of the support wheel (413) and the limiting wheel (423) are covered with a wear-resistant rubber layer to avoid damaging the pipe surface.

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