Shrimp waist elbow boat-shaped position welding positioner and its limiting assembly

Abstract

This invention discloses a welding positioner for a boat-shaped curved head and its limiting components, belonging to the technical field of welding positioner equipment. The positioner includes a rotary mechanism, a lifting adjustment mechanism, a tilting adjustment mechanism, and a clamping fixture. A closed-loop bidirectional gapless limiting component is set between the tilting support frame and the lifting support seat. This component includes an arc-shaped locking beam, a reaction force bracket, first and second self-increasing force locking mechanisms with opposite wedge tightening directions, a differential equal load pre-tightening mechanism, and a radial compliant support mechanism. The two locking mechanisms are in pre-contact simultaneously in the welding state. When the overturning moment generated by the rotation of the curved head changes direction, the corresponding locking mechanism converts the tangential load into an increased normal locking force. The radial compliant support mechanism allows the reaction force bracket to radially compensate and restrict the arc tangential displacement, thereby forming an independent welding support branch outside the attitude adjustment transmission branch to reduce the boat-shaped attitude fluctuation caused by transmission backlash.

Description

Technical Field

[0001] This invention relates to the field of welding positioner for shrimp-shaped bends, and particularly to a welding positioner for boat-shaped shrimp-shaped bends and its limiting components. Background Technology

[0002] Shrimp-shaped elbows are typically composed of multiple obliquely cut circular pipe segments assembled sequentially to form a circumferential weld along the oblique cut joint. Due to the different oblique cut directions and spatial postures of different segments, it is usually necessary to adjust the workpiece tilt angle and center position using a welding positioner before welding the current circumferential weld. This establishes a boat-shaped welding position suitable for continuous rotary welding of the current circumferential weld. Existing positioners typically use a motor, reducer, and gear transmission mechanism to drive the workpiece to tilt. After the angle adjustment is completed, the tilt position is maintained by a motor brake, reduction mechanism, or additional brake. The rotary mechanism then drives the workpiece to rotate continuously.

[0003] However, the shrimp-shaped elbow is an irregularly shaped workpiece with an asymmetrical mass distribution on the rotating shaft of the weld ring to be welded. Even if the weld ring to be welded has been accurately adjusted to the predetermined boat-shaped position in a static state, when the workpiece rotates continuously around the rotating shaft corresponding to the current weld, the position of the workpiece's center of mass relative to the direction of gravity still changes with the rotation phase. As a result, the overturning moment acting on the tilting bearing mechanism also changes accordingly and may reverse direction. When the tilting angle is mainly maintained by a series transmission chain consisting of a motor, reducer, drive gear, and sector teeth, the reversal of the alternating overturning moment can easily cause the existing tooth side working surface inside the transmission chain to change sides with the direction of force. This, combined with the torsional elasticity of the reduction mechanism, the elastic deformation of the bearing, and the deflection of the support structure, causes the small angular displacement of the output end, which is not obvious in the static state, to appear periodically during continuous rotation. If the angular displacement is suppressed simply by increasing the braking force or increasing the preload of the transmission pair, it will increase the attitude adjustment drive burden and the internal forces of the structure. If discrete positioning pin holes are used, it is difficult to adapt to the continuous boat-shaped tilting angles corresponding to different elbow specifications and different segments.

[0004] Therefore, this invention proposes a shrimp-shaped waist bend and boat-shaped position welding positioner and its limiting components to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a welding positioner for a shrimp-shaped bend and a boat-shaped position, and its limiting components, to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a welding positioner for a shrimp-shaped elbow, comprising a fixed frame, a rotary mechanism, a lifting adjustment mechanism, a tilt adjustment mechanism, and a clamping fixture for clamping the shrimp-shaped elbow. The rotary mechanism is mounted on the fixed frame, the lifting adjustment mechanism is mounted on the rotary mechanism, and the tilt adjustment mechanism is mounted on the lifting adjustment mechanism. The tilt adjustment mechanism includes a tilt support frame, a tilt shaft, and a tilt drive mechanism for driving the tilt support frame to rotate around the tilt shaft. The lifting adjustment mechanism includes a lifting support seat for supporting the tilt adjustment mechanism. A closed-loop force-ring bidirectional gapless limiting component is provided between the tilt support frame and the lifting support seat. The closed-loop force-ring bidirectional gapless limiting component includes an arc-shaped locking beam, a reaction force bracket, a first-direction self-increasing force locking mechanism, a second-direction self-increasing force locking mechanism, a differential equal-load pre-tightening mechanism, and a radial compliant support mechanism. The arc-shaped locking beam is fixedly connected to the inclined bearing frame and extends along the arc direction with the axis of the inclined rotating shaft as the center of the arc. The arc-shaped locking beam has an inner arc working surface and an outer arc working surface that extend continuously along its arc direction. The reaction force bracket spans the inner and outer sides of the arc-shaped locking beam and forms a locking cavity for the arc-shaped locking beam to move relative to each other along the arc direction. The first directional self-increasing force locking mechanism and the second directional self-increasing force locking mechanism are disposed in the locking cavity and correspond to the outer arc working surface and the inner arc working surface, respectively. The first directional self-increasing force locking mechanism and the second directional self-increasing force locking mechanism have opposite wedging directions. When the arc-shaped locking beam has a tendency to move relative to the reaction force frame along the first arc tangential direction, the first directional self-increasing force locking mechanism converts the tangential force it bears into an additional normal locking force toward the arc-shaped locking beam. When the arc-shaped locking beam has a tendency to move along the second arc tangential direction opposite to the first arc tangential direction, the second directional self-increasing force locking mechanism converts the tangential force it bears into an additional normal locking force toward the arc-shaped locking beam. The differential equal load pre-tightening mechanism acts simultaneously on the first direction self-increasing force locking mechanism and the second direction self-increasing force locking mechanism, so that the two maintain pre-contact with the corresponding outer arc working surface and inner arc working surface respectively in the load locking state, and allow the other self-increasing force locking mechanism to maintain basic pre-contact when one of the self-increasing force locking mechanisms further weds in response to the tangential load in the corresponding direction. The reaction force support frame is connected to the lifting support seat through a radial compliant support mechanism. The radial compliant support mechanism allows the reaction force support frame to generate local radial elastic compensation displacement along the arc-shaped locking beam at the locking position of the reaction force support frame, and restricts the reaction force support frame from generating displacement along the local arc tangent of the arc-shaped locking beam corresponding to the change of tilt posture of the tilted support frame. The tilting drive mechanism and the tilting support frame form an attitude adjustment transmission branch for changing the boat-shaped welding posture of the shrimp-shaped elbow. The arc-shaped locking beam, the first direction self-increasing force locking mechanism, the second direction self-increasing force locking mechanism, the reaction force bracket, and the radial compliant support mechanism form a welding support branch that connects the tilting support frame and the lifting support seat and is connected in parallel with the attitude adjustment transmission branch. This allows at least part of the alternating overturning load acting on the tilting support frame during the rotation of the shrimp-shaped elbow with the slewing mechanism to be transmitted to the lifting support seat via the welding support branch.

[0007] Preferably, the first directional self-increasing force locking mechanism includes a first wedge-shaped locking slider, a first friction locking shoe, and a first wedge-shaped guide surface disposed on the reaction force frame. The first friction locking shoe is disposed on the side of the first wedge-shaped locking slider facing the outer arc working surface. The second directional self-increasing force locking mechanism includes a second wedge-shaped locking slider, a second friction locking shoe, and a second wedge-shaped guide surface disposed on the reaction force frame. The second friction locking shoe is disposed on the side of the second wedge-shaped locking slider facing the inner arc working surface. The first wedge-shaped guide surface and the second wedge-shaped guide surface have opposite wedge lifting directions relative to the local arc tangential direction of the arc-shaped locking beam, so that the first wedge-shaped locking slider and the second wedge-shaped locking slider respectively respond to the arc tangential force in opposite directions and generate an increased pressing displacement toward the arc-shaped locking beam.

[0008] Preferably, the differential equal-load preload mechanism includes an equal-load pressure bridge, a floating fulcrum, a disc spring preload assembly, a first push rod, and a second push rod. The equal-load pressure bridge is oscillatingly mounted on the reaction frame via the floating fulcrum. The first force-bearing end of the equal-load pressure bridge acts on the first wedge-shaped locking slider via the first push rod, and the second force-bearing end of the equal-load pressure bridge acts on the second wedge-shaped locking slider via the second push rod. The disc spring preload assembly applies a preload force to the equal-load pressure bridge, so that the first friction locking shoe and the second friction locking shoe maintain pre-contact simultaneously, and the equal-load pressure bridge can oscillate around the floating fulcrum according to the relative displacement difference between the first wedge-shaped locking slider and the second wedge-shaped locking slider.

[0009] Preferably, the radially compliant support mechanism includes a mounting base and at least two sets of mutually parallel elastic support plates. The mounting base is fixed to the lifting bearing base, and the elastic support plates are connected between the mounting base and the reaction force bracket to form a flexible parallel guide structure. The arrangement of the elastic support plates enables the reaction force bracket to generate compensated translation through elastic bending along the local radial direction of the arc-shaped locking beam, and makes the load of the local arc tangential direction of the arc-shaped locking beam mainly transmitted along the high stiffness direction of the elastic support plates.

[0010] Preferably, the reaction force frame is a C-shaped frame spanning the inner and outer circular arc working surfaces. The first and second friction locking shoes are arranged radially opposite each other along the arc-shaped locking beam, so that the foundation pre-tightening normal force and its reaction force applied by the first and second friction locking shoes to the arc-shaped locking beam are at least partially closed through the inside of the reaction force frame. The circular arc tangential bearing reaction force applied by the arc-shaped locking beam to the reaction force frame is transmitted to the lifting bearing seat through the radial compliant support mechanism.

[0011] Preferably, the closed-loop bidirectional gapless limiting assembly further includes a unified wedge release mechanism. The unified wedge release mechanism includes a release drive, a release lever connected to the release drive, and a wedge release linkage connected to the release lever. The wedge release linkage is respectively driven to cooperate with the first wedge locking slider and the second wedge locking slider to drive the two wedge locking sliders to exit their respective force-increasing wedge positions when the release drive performs the release action, so that the first friction locking shoe and the second friction locking shoe form a release gap with the corresponding arc working surface for the arc locking beam to perform posture adjustment movement.

[0012] Preferably, the tilting drive mechanism includes a tilting drive motor, a reduction mechanism, a drive pinion, and a sector tooth fixedly connected to the tilting support frame. The tilting drive motor drives the drive pinion and the sector tooth to mesh and transmit power via the reduction mechanism. The welded support branch is connected between the output side of the tilting support frame and the lifting support seat, and forms an anti-overturning load transmission path across the drive pinion, sector tooth, and reduction mechanism when the closed force ring bidirectional backlash-free limiting component is in the load locking state.

[0013] This invention provides a limit component for welding the boat-shaped position of a shrimp-shaped bend, which is applied in a positioner for welding the boat-shaped position of a shrimp-shaped bend. The limit component is a closed force ring type bidirectional gapless limit component.

[0014] The technical effects and advantages of this invention are as follows: 1. This invention sets up an independent welding bearing branch between the output side of the inclined bearing frame and the lifting bearing seat, so that the alternating overturning load during the rotary welding of the shrimp waist bend no longer has to be transmitted in reverse through the sector teeth, the driving pinion, the reduction mechanism and the inclined drive motor in sequence. Therefore, it can reduce the conversion of the tooth backlash, torsional elasticity and braking flexibility of the above-mentioned series transmission components to the attitude error of the inclined output end. At the same time, the welding bearing path only takes over the load after the attitude adjustment is completed, so it will not continuously increase the driving resistance during the normal tilt adjustment stage in order to obtain higher welding state stiffness.

[0015] 2. This invention utilizes two self-amplifying locking mechanisms with opposite wedge clamping directions to correspond to the two directions of the overturning moment, and uses a differential equal-load pre-tightening mechanism to maintain the foundation pre-contact between the two locking branches before the overturning moment reverses. Therefore, when the alternating overturning load passes through zero and changes direction, it is not necessary to first cross the design free gap between the traditional pin hole, tooth side, or brake block to establish the reverse load by the other locking branch. Furthermore, the larger the tangential load in the corresponding direction, the more obvious the additional normal locking effect formed by the corresponding wedge locking mechanism, thereby improving the attitude maintenance capability during the reversal process.

[0016] 3. The present invention further distinguishes the non-attitude error direction of the arc-shaped locking beam from the motion direction that truly corresponds to the change of the ship's angular shape by using a radially compliant and tangentially rigid support relationship. This allows for compensation space for manufacturing errors and radial deformation under load, while the tangential arc is still constrained by high rigidity. Furthermore, the closed force ring inside the reaction force frame reduces the additional load caused by the direct transmission of the foundation preload to the tilting bearing and the main frame. Thus, the two contradictory requirements of continuous angle gapless locking and prevention of over-constraint of the structure can be coordinated and achieved in the same limiting component. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall first state structure of the present invention; Figure 2 This is a schematic diagram of the overall second-state structure of the present invention; Figure 3 This is a schematic diagram of the assembly structure of the closed force ring type bidirectional gapless limiting component and the inclined bearing frame of the present invention; Figure 4 This is a schematic diagram of the unified wedge release mechanism structure and release state of the present invention; Figure 5 This is a schematic diagram of the structure of the limiting component of the present invention after partial radial sectioning along the arc-shaped locking beam; Figure 6 This is a schematic diagram showing the reverse wedging relationship between the first-direction self-increasing force locking mechanism and the second-direction self-increasing force locking mechanism of the present invention; Figure 7 This is a schematic diagram of the connection structure of the tilt adjustment mechanism, the lifting support seat, and the closed force ring type bidirectional gapless limiting component of the present invention; Figure 8 This is a schematic diagram of the flexible parallel guide structure of the radial compliant support mechanism of the present invention; Figure 9 This is a schematic diagram showing the connection relationship between the differential equal load preload mechanism and the two wedge-shaped locking sliders of the present invention.

[0018] In the diagram: 1. Fixed frame; 2. Tilting adjustment mechanism; 21. Tilting support frame; 22. Tilting shaft; 23. Tilting drive motor; 24. Reduction mechanism; 25. Drive pinion; 26. Sector gear; 27. Tilting drive mechanism; 3. Lifting adjustment mechanism; 31. Lifting support seat; 32. Lifting drive motor; 33. Lifting reduction mechanism; 34. Lifting lead screw; 35. Lifting guide mechanism; 4. Rotation mechanism; 41. Rotation drive motor; 42. Rotation reduction mechanism; 43. Rotation drive gear; 44. Rotation bearing; 5. Closed-loop bidirectional backlash-free limiting assembly; 51. Arc-shaped locking beam; 511. Inner arc working surface; 512. Outer arc working surface; 52. Reaction frame; 520. Locking cavity; 53. First direction self- Force-increasing locking mechanism; 531, first wedge-shaped locking slider; 532, first friction locking shoe; 533, first wedge-shaped guide surface; 54, second-direction self-increasing force locking mechanism; 541, second wedge-shaped locking slider; 542, second friction locking shoe; 543, second wedge-shaped guide surface; 55, differential equal-load preload mechanism; 551, equal-load pressure bridge; 552, floating fulcrum; 553, disc spring preload assembly; 554, first force-bearing end; 555, second force-bearing end; 556, first push rod; 557, second push rod; 56, unified wedge release mechanism; 561, release drive component; 562, release pull rod; 563, wedge release linkage component; 57, radial compliant support mechanism; 571, elastic support plate; 572, mounting base; 6, clamping fixture. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] In this embodiment, the shrimp-shaped elbow is formed by assembling multiple obliquely cut pipe sections. When welding any current circumferential weld, the current circumferential weld is used as the current reference weld. The tilt adjustment mechanism 2 is used to make the plane where the current reference weld is located reach a predetermined ship-shaped welding posture. Then, the lifting adjustment mechanism 3 is used to make the geometric center of the current reference weld and the rotation axis of the rotation mechanism 4 meet the predetermined alignment requirements. The "ship-shaped welding posture" referred to in this embodiment is determined according to the specific welding process. Preferably, the plane where the current circumferential weld to be welded is located is close to perpendicular to the ground, and the welding area corresponding to the fixed welding gun is kept in a predetermined spatial position suitable for the stability of the molten pool when the workpiece rotates continuously. First, each obliquely cut circumferential weld with different spatial directions is converted into a reference geometric state in which the equipment can continuously weld with a basically constant welding position. Then, mechanical holding conditions are established around this state, thereby separating the complex overall spatial shape of the shrimp-shaped elbow from the local welding posture of the current weld.

[0021] like Figures 1 to 9 As shown, this embodiment discloses a welding positioner for a shrimp-shaped elbow, including a fixed frame 1, a rotary mechanism 4, a lifting adjustment mechanism 3, a tilt adjustment mechanism 2, and a clamping fixture 6 for clamping the shrimp-shaped elbow. The rotary mechanism 4 is mounted on the fixed frame 1, the lifting adjustment mechanism 3 is mounted on the rotary mechanism 4, and the tilt adjustment mechanism 2 is mounted on the lifting adjustment mechanism 3. The tilt adjustment mechanism 2 includes a tilt support frame 21, a tilt rotating shaft 22, and a tilt drive mechanism 27 that drives the tilt support frame 21 to rotate around the tilt rotating shaft 22. The lifting adjustment mechanism 3 includes a lifting support seat 31 for supporting the tilt adjustment mechanism 2. A closed force ring type bidirectional gapless limiting component 5 is provided between the tilt support frame 21 and the lifting support seat 31. Specifically: The fixed frame 1 provides a rigid mounting base for the rotary mechanism 4. The rotary mechanism 4 includes a rotary drive motor 41, a rotary reduction mechanism 42, a rotary drive gear 43, and a rotary bearing 44. The fixed ring of the rotary bearing 44 is connected to the fixed frame 1, and the movable ring of the rotary bearing 44 carries the lifting adjustment mechanism 3. The output end of the rotary drive motor 41 drives the rotary drive gear 43 via the rotary reduction mechanism 42. The rotary drive gear 43 meshes with the gear ring of the rotary bearing 44, thereby enabling the movable ring and the lifting adjustment mechanism 3, tilt adjustment mechanism 2, clamping fixture 6, and other components located thereon to rotate. The workpieces rotate continuously together. The rotary drive motor 41 is preferably a servo motor that can perform low-speed stable speed regulation. The rotary reduction mechanism 42 can be an RV reducer or other reduction mechanism that can meet the design load and low-speed stability. The welding torch can be kept in a relatively fixed welding position, while the workpiece is continuously passed through the welding position by the rotary mechanism at an angular velocity that matches the welding speed. This transforms the complex trajectory of manually moving the welding torch around the irregular bend into a controlled mechanical rotary motion, and provides a definite motion source for the change of the eccentric workpiece overturning moment with the rotation phase, as described later.

[0022] The lifting adjustment mechanism 3 includes a lifting support 31, a lifting drive motor 32, a lifting reduction mechanism 33, a lifting screw 34, and a lifting guide mechanism 35. The lifting guide mechanism 35 is vertically mounted on the movable support structure of the rotary mechanism 4. The lifting support 31 and the lifting guide mechanism 35 are slidably coupled. The lifting screw 34 is arranged along the lifting direction and engages with a nut on the lifting support 31. The lifting drive motor 32 drives the lifting screw 34 to rotate via the lifting reduction mechanism 33, causing the lifting support 31 to rise and fall smoothly along the lifting guide mechanism 35. 34 can be a trapezoidal lead screw with mechanical holding capability or an independent braking mechanism when using a ball screw. The lifting guide mechanism 35 can be two spaced linear guides to bear the eccentric bending moment generated by the workpiece. The rotational motion of the lead screw is converted into the linear displacement of the lifting bearing seat, so that the center of the current weld ring to be welded, which has completed the initial adjustment of the tilt posture, approaches the rotation axis of the rotary mechanism vertically. The lateral and overturning loads are borne by the paired guides, thereby avoiding the significant drift of the center position under load caused by only using the lead screw to bear the lateral load.

[0023] The tilt adjustment mechanism 2 is mounted on the lifting support 31. The tilt support frame 21 is rotatably supported on the lifting support 31 via the tilt shaft 22. The tilt drive mechanism 27 includes a tilt drive motor 23, a reduction mechanism 24, a drive pinion 25, and a sector gear 26. The sector gear 26 is rigidly connected to the tilt support frame 21 and forms an arc-shaped tooth segment centered on the tilt shaft 22. The tilt drive motor 23 drives the drive pinion 25 via the reduction mechanism 24. The drive pinion 25 meshes with the sector gear 26 and pushes the tilt support frame 21 to rotate around the tilt shaft 22. The encoder of the tilt drive motor 23 is mounted on the tilt support 31. The angle detection component of the rotating shaft 22 can be used to determine the actual tilt angle, but the angle detection component mainly undertakes the function of posture detection and does not serve as a welding load-bearing component. The high-speed, low-torque motion output by the motor is converted into low-speed, high-torque motion by the reduction mechanism, and further driven by the radius amplification effect of the pinion and sector gear to complete the continuous angle adjustment of the heavy-duty shrimp-shaped elbow, so that the circumferential welds formed by different bevel angles can stay at the actual required angle. At the same time, since the gear and reduction transmission chain have the matching clearance and elasticity required for the motion function, the present invention does not require the transmission chain to serve as the only high-rigidity anti-overturning path in the welding stage.

[0024] The clamping fixture 6 is rigidly installed on the inclined support frame 21. It can be used with adjustable support blocks, mechanical clamping parts, clamping parts, or other clamping forms that can make the workpiece and the inclined support frame 21 form a reliable overall motion relationship, depending on the diameter and segment structure of the curved head. Preferably, the main clamping position avoids the current weld seam and its direct heat-affected zone. The structural strength and clamping force of the clamping fixture 6 should meet the requirement that the workpiece does not slip relative to the inclined support frame 21 under the action of the maximum rotation phase overturning load, which will affect the welding posture. The closed force ring type bidirectional gapless limiting component 5 controls the angle of the inclined support frame relative to the lifting support seat. Only when the workpiece and the inclined support frame maintain a reliable position transmission relationship can the angle constraint be further converted into the posture constraint of the weld seam. Therefore, the clamping fixture undertakes the rigid motion transmission function between the workpiece and the posture adjustment mechanism, and does not need to undertake the bidirectional self-increasing force locking function of the present invention.

[0025] The closed-loop bidirectional gapless limiting assembly 5 includes an arc-shaped locking beam 51, a reaction force bracket 52, a first-direction self-increasing force locking mechanism 53, a second-direction self-increasing force locking mechanism 54, a differential equal-load pre-tightening mechanism 55, and a radially compliant support mechanism 57. The arc-shaped locking beam 51 is fixedly connected to the inclined bearing frame 21 and extends along an arc direction with the axis of the inclined rotating shaft 22 as the center of the arc. The arc-shaped locking beam 51 has an inner arc working surface 511 and an outer arc working surface 512 that extend continuously along its arc direction. The reaction force bracket 52 spans across the arc-shaped locking beam. The inner and outer sides of 51 form locking cavities 520 for the relative movement of the arc-shaped locking beam 51 along the arc direction. The arc-shaped locking beam 51 adopts an arc-shaped beam structure with high bending and torsional stiffness. In the locking area, an inner arc working surface 511 and an outer arc working surface 512 are formed in opposite directions. The two arc working surfaces are continuously set along the effective tilt adjustment angle range. The effective arc length of the arc-shaped locking beam 51 should ensure that the tilt bearing frame 21 always has sufficient length within the locking cavity 520 of the reaction force frame 52 when it moves between the maximum and minimum design tilt angles.

[0026] The arc-shaped locking beam 51 and the inclined rotating shaft 22 are arranged in a co-centric manner, so that when the inclined bearing frame 21 adjusts its angle, different material sections of the arc-shaped locking beam 51 pass through the locking cavity 520 in a fixed spatial position in sequence. The continuous arc working surface replaces the positioning hole or positioning groove corresponding to the fixed angle, so that the mechanical bearing position of the limiting component is not limited by discrete hole positions. Therefore, the same limiting mechanism can establish locking for the actual boat-shaped tilt angle formed by different pipe diameters, different oblique cutting angles and manufacturing errors within the tilt adjustment range. At the same time, the arc trajectory and the inclined rotating shaft are co-centric, which can keep the relative motion geometry stable in the released state.

[0027] The first-direction self-increasing force locking mechanism 53 and the second-direction self-increasing force locking mechanism 54 are disposed in the locking cavity 520 and correspond to the outer arc working surface 512 and the inner arc working surface 511, respectively. The first-direction self-increasing force locking mechanism 53 and the second-direction self-increasing force locking mechanism 54 have opposite wedging directions. When the arc-shaped locking beam 51 tends to move relative to the reaction force frame 52 along the first arc tangential direction, the first-direction self-increasing force locking mechanism 53 converts the tangential force it bears into an additional normal locking force toward the arc-shaped locking beam 51. When the arc-shaped locking beam 51 tends to move along the second arc tangential direction opposite to the first arc tangential direction, the second-direction self-increasing force locking mechanism 54 converts the tangential force it bears into an additional normal locking force toward the arc-shaped locking beam 51.

[0028] The differential equal load preload mechanism 55 acts simultaneously on the first direction self-increasing force locking mechanism 53 and the second direction self-increasing force locking mechanism 54, so that the two maintain pre-contact with the corresponding outer arc working surface 512 and inner arc working surface 511 respectively in the load locking state, and allow the other self-increasing force locking mechanism to maintain basic pre-contact when one self-increasing force locking mechanism further weds in response to the tangential load in the corresponding direction.

[0029] The reaction force support 52 is connected to the lifting support 31 via a radial compliant support mechanism 57. The radial compliant support mechanism 57 allows the reaction force support 52 to generate local radial elastic compensation displacement along the arc-shaped locking beam 51 at the locking position of the reaction force support 52, and restricts the reaction force support 52 from generating displacement along the local arc tangential of the arc-shaped locking beam 51 corresponding to the tilting posture change of the tilting support 21.

[0030] The first directional self-increasing force locking mechanism 53 includes a first wedge-shaped locking slider 531, a first friction locking shoe 532, and a first wedge-shaped guide surface 533 disposed on the reaction force frame 52. The first friction locking shoe 532 is disposed on the side of the first wedge-shaped locking slider 531 facing the outer arc working surface 512. The second directional self-increasing force locking mechanism 54 includes a second wedge-shaped locking slider 541, a second friction locking shoe 542, and a second wedge-shaped guide surface 543 disposed on the reaction force frame 52. The second friction locking shoe 542 is disposed on the side of the second wedge-shaped locking slider 541 facing the inner arc working surface 511. The first wedge-shaped guide surface 533 and the second wedge-shaped guide surface 543 have opposite wedge lifting directions relative to the local arc tangential direction of the arc-shaped locking beam 51, so that the first wedge-shaped locking slider 531 and the second wedge-shaped locking slider 541 respectively respond to the arc tangential force in opposite directions and generate increased pressing displacement toward the arc-shaped locking beam 51.

[0031] The first wedge-shaped locking slider 531 of the first direction self-amplifying locking mechanism 53 can be moved in a controlled manner along the first wedge-shaped guide surface 533. The extension direction of the first wedge-shaped guide surface 533 forms an acute angle with respect to the arc tangent of the arc-shaped locking beam 51 at the locking position, so that when the first wedge-shaped locking slider 531 moves along the predetermined wedge tightening direction, it simultaneously generates a displacement component along the arc tangent and a normal displacement component toward the outer arc working surface 512.

[0032] The second wedge-shaped locking slider 541 of the second direction self-increasing force locking mechanism 54 forms a mirror or reverse wedge-lift relationship with the second wedge-shaped guide surface 543, so that the effective wedge-tightening direction of the second wedge-shaped locking slider 541 is opposite to the effective wedge-tightening direction of the first wedge-shaped locking slider 531.

[0033] The first friction locking shoe 532 and the second friction locking shoe 542 are respectively disposed on the side of the two wedge-shaped locking sliders near the arc-shaped locking beam 51, and allow the friction locking shoe to have a small oscillation relative to the wedge-shaped slider to meet the fitting requirements or to achieve adaptive fitting by using a spherical pad. When the arc-shaped locking beam attempts to move relative to the reaction force frame along the tangential direction of the first arc, the tangential friction traction of the first friction locking shoe causes the first wedge-shaped locking slider to enter a smaller and smaller wedge-shaped space along the first wedge-shaped guide surface. The tangential movement trend is thus converted into a larger normal pressing force. After the load is reversed, the second wedge-shaped locking slider completes the same self-aggregating force process according to the opposite geometric relationship, so that the electronic control system does not need to identify the overturning direction first and then actively switch the braking actuator.

[0034] The wedge angles of the two wedge guide surfaces should be determined comprehensively based on the friction coefficient between the arc-shaped locking beam and the friction locking shoe, the friction conditions between the wedge slider and the wedge guide surface, the maximum overturning load, and the required release performance. When it is required that the wedge slider maintains mechanical self-locking after the tangential external load disappears, the wedge angle of the wedge pair can be kept within its self-locking condition range and forcibly released by the unified wedge release mechanism 56. When it is desired that the wedge can be easily released after unloading, the wedge angle can also be set to a range that has a self-increasing force effect but does not form a completely static self-locking, and the disc spring preload assembly 553 can be used to continuously maintain the basic contact. For simplified wedge pairs that do not consider other complex friction interfaces, the friction angle of the wedge pair can be used as a reference for the selection of the wedge angle, and the final dimensions should be checked for stress according to the actual friction material, surface treatment state, and safety factor.

[0035] The differential equal-load preload mechanism 55 includes an equal-load pressure bridge 551, a floating fulcrum 552, a disc spring preload assembly 553, a first push rod 556, and a second push rod 557. The equal-load pressure bridge 551 is swayably mounted on the reaction frame 52 via the floating fulcrum 552. The first force-bearing end 554 of the equal-load pressure bridge 551 acts on the first wedge-shaped locking slider 531 via the first push rod 556, and the second force-bearing end 555 of the equal-load pressure bridge 551 acts on the second wedge-shaped locking slider 541 via the second push rod 557. The disc spring preload assembly 553 applies a preload force to the equal-load pressure bridge 551, so that the first friction locking shoe 532 and the second friction locking shoe 542 simultaneously maintain pre-contact, and the equal-load pressure bridge 551 can swing around the floating fulcrum 552 according to the relative displacement difference between the first wedge-shaped locking slider 531 and the second wedge-shaped locking slider 541.

[0036] The differential equal-load preload mechanism 55 is used to solve the contact continuity of the two opposing self-amplifying locking mechanisms when the overturning moment crosses zero and reverses direction. The middle part of the equal-load pressure bridge 551 is oscillatingly supported on the reaction force frame 52 through the floating fulcrum 552. The first force-bearing end 554 acts on the preload end of the first wedge-shaped locking slider 531 through the first push rod 556 with a spherical end. The second force-bearing end 555 acts on the preload end of the second wedge-shaped locking slider 541 through the second push rod 557. The disc spring preload assembly 553 applies an elastic force in the locking direction to the equal-load pressure bridge 551 through the preload screw or preload seat. The floating fulcrum 552 can be composed of a pin and a spherical pad or a spherical bearing, so that the equal-load pressure bridge 551 can generate a small-angle differential oscillation around the fulcrum, but not allow The equal load bridge is completely detached from the reaction force frame. During commissioning, the compression of the disc spring preload assembly 553 is changed to ensure that the first friction locking shoe 532 and the second friction locking shoe 542 maintain a contact pressure no lower than the design foundation value when there is no significant tangential overturning load. The preload input generated by the disc spring is distributed to the two locking branches through the swinging equal load bridge. When the first wedge-shaped locking slider is further wedged in by the external load, the equal load bridge allows the first end to undergo additional displacement by swinging at a small angle without forcing the second end to be completely unloaded. Therefore, the other friction locking shoe still maintains foundation contact. The same applies after the overturning direction is reversed. In this way, the main load-bearing action is transferred between the two directions through the already contacted branches, rather than through a section of unrestrained mechanical idle stroke.

[0037] To prevent the differential equal-load preload mechanism 55 from bearing excessive foundation pressure on one locking branch due to assembly errors, at least one of the first push rod 556 and the second push rod 557 can be equipped with a thread length adjustment part. During the initial assembly, the two friction locking shoes can be made to have a basically consistent pre-contact state under the condition of no external overturning load. Mechanical stroke limiting surfaces can also be set in the maximum wedging direction of the two wedge-shaped locking sliders. This prevents the wedge-shaped sliders from entering the wedge space indefinitely when the friction material experiences abnormal wear or the external load exceeds the design value. The length adjustment solves the influence of the manufacturing dimension chain on the preload balance of the foundation on both sides, while the mechanical end limit controls the maximum displacement that the wedge-shaped sliders can produce. Therefore, even if the elastic preload and self-increasing force are present at the same time, the geometric movement of the locking mechanism still has a clear boundary, which is conducive to improving the consistency of repeated locking states and avoiding difficulty in release due to excessive wedging.

[0038] The radially compliant support mechanism 57 includes a mounting base 572 and at least two sets of mutually parallel elastic support plates 571. The mounting base 572 is fixed to the lifting bearing seat 31. The elastic support plates 571 are connected between the mounting base 572 and the reaction force bracket 52 and form a flexible parallel guide structure. The arrangement of the elastic support plates 571 enables the reaction force bracket 52 to generate compensated translation through elastic bending along the local radial direction of the arc-shaped locking beam 51, and makes the load of the local arc tangential direction of the arc-shaped locking beam 51 mainly transmitted along the high stiffness direction of the elastic support plates 571. The radially compliant support mechanism 57 adopts a flexible parallelogram structure without sliding kinematic pairs. The mounting base 572 is rigidly connected to the lifting bearing seat 31, and two sets or two pairs of elastic support plates 571 are connected to the mounting base 572 and the reaction force bracket 52 in parallel.

[0039] In this embodiment, the long axis of each elastic support piece 571 preferably extends tangentially along the local arc of the arc-shaped locking beam 51 at the position of the reaction frame, and the thickness direction of the elastic support piece, which is prone to bending, is oriented towards the local radial direction. Therefore, when the reaction frame 52 is subjected to radial force, it can form a small-range radial translation through the bending of the elastic support piece 571. When subjected to arc tangential load, the load is mainly transmitted along the axial high stiffness direction of the elastic support piece. The two sets of parallel elastic support pieces jointly constrain the reaction frame to undergo significant additional rotation, and protective limiting surfaces can be set at both ends of the allowable radial stroke to prevent abnormal loads from causing the elastic support piece to exceed the allowable elastic deformation range. The flexible support provides compensation through the elastic deformation of the material without the fit clearance of traditional kinematic pairs such as slide rails and rollers. Therefore, it can allow the radial micro-displacement of the arc-shaped locking beam due to machining roundness, installation eccentricity, or deflection under load, without reintroducing the guide clearance that affects the accuracy of arc tangential locking in order to obtain this compensation.

[0040] Since the arc-shaped locking beam 51 is centered on the inclined pivot 22, and the reaction force bracket 52 is located in a fixed spatial locking position relative to the lifting support 31, when different material sections of the arc-shaped locking beam pass through this locking position with the tilt adjustment, their local tangential and local radial directions at this position remain fixed relative to the reaction force bracket. Therefore, the elastic support plate 571 only needs to be arranged in a fixed direction for the position of the reaction force bracket, without actively turning with the tilt angle. When the arc track rotates around its own center, the tangential direction of the arc at the fixed locking position belongs to a fixed direction in the equipment base.

[0041] The reaction force frame 52 is a C-shaped frame spanning the inner arc working surface 511 and the outer arc working surface 512. The first friction locking shoe 532 and the second friction locking shoe 542 are arranged opposite each other in the local radial direction along the arc-shaped locking beam 51, so that the foundation pre-tightening normal force and its reaction force applied by the first friction locking shoe 532 and the second friction locking shoe 542 to the arc-shaped locking beam 51 are closed at least partially through the inside of the reaction force frame 52. The arc tangential bearing reaction force applied by the arc-shaped locking beam 51 to the reaction force frame 52 is transmitted to the lifting bearing seat 31 through the radial compliant support mechanism 57.

[0042] The first direction self-increasing force locking mechanism 53 is located on the outer arc side of the locking cavity 520, and the second direction self-increasing force locking mechanism 54 is located on the inner arc side of the locking cavity 520. Therefore, the first friction locking shoe 532 and the second friction locking shoe 542 can act towards each other along the local radial direction of the arc-shaped locking beam 51. The contact surfaces of the first friction locking shoe 532 and the second friction locking shoe 542 are preferably machined into arc surfaces that match the local curvature of the corresponding arc working surface, and a replaceable wear-resistant friction layer can be provided so that the friction parts can be replaced after the wear reaches the allowable value without replacing the entire reaction force frame. The two friction locking shoes arranged opposite each other first form a clamping relationship inside the reaction force frame. The basic normal pre-tightening force is mainly closed through the arc-shaped beam and the reaction force frame itself, without having to apply all the pre-tightening force to the tilting shaft bearing and the frame, thereby improving the friction bearing conditions while reducing the additional impact of the basic clamping force on the geometric accuracy of the tilting mechanism.

[0043] The reaction force bracket 52 is not completely rigidly fixed to the lifting support 31 in all directions, but is connected to the lifting support 31 through a radial compliant support mechanism 57. The radial compliant support mechanism 57 allows the reaction force bracket 52 to undergo limited elastic compensation without kinematic pairs in the local radial direction along the arc-shaped locking beam 51 at the locking position. At the same time, it forms a support stiffness in the arc tangential direction that is much higher than the radial flexibility. Therefore, the roundness error, installation coaxiality error or radial micro-deformation caused by the load of the arc-shaped locking beam 51 can be absorbed by the radial follow-up of the reaction force bracket 52. The arc tangential movement that actually corresponds to the change of tilt posture is still constrained by the limiting component. This avoids rigidly sealing off the harmless radial error and converting it into additional tilt deformation in order to eliminate tangential backlash.

[0044] In this embodiment, "gapless" and "bidirectional gapless" mean that after the limiting component enters the load-bearing locking state, both the first and second load-bearing branches are kept in contact by the pre-tightening mechanism. There is no design gap that requires a predetermined free stroke before the reverse load can be formed. It does not mean that the components do not have elastic deformation of materials under load. In this embodiment, "closed force ring" means that the main basic normal pre-tightening force between the first friction locking shoe, the arc-shaped locking beam, the second friction locking shoe and the reaction force frame forms a reaction force closure inside the local component. The tangential load used to balance the overturning moment of the shrimp waist bend is then transmitted to the lifting load seat through the radial compliant support mechanism. Through the above definition, the structural relationship of this embodiment can be distinguished from ordinary gap-type stops, one-way wedge clamping mechanisms and structures that simply rely on increasing the braking torque of the drive.

[0045] The closed-loop bidirectional gapless limiting assembly 5 also includes a unified wedge release mechanism 56. The unified wedge release mechanism 56 includes a release drive 561, a release lever 562 connected to the release drive 561, and a wedge release linkage 563 connected to the release lever 562. The wedge release linkage 563 is in transmission cooperation with the first wedge locking slider 531 and the second wedge locking slider 541 respectively, so that when the release drive 561 performs the release action, it drives the two wedge locking sliders to exit their respective force-increasing wedge positions, so that the first friction locking shoe 532 and the second friction locking shoe 542 form a release gap with the corresponding arc working surface for the arc-shaped locking beam 51 to perform posture adjustment movement.

[0046] The release drive 561 of the unified wedge release mechanism 56 can be a cylinder, hydraulic cylinder, electric push rod or other linear drive. In the preferred embodiment, a cylinder drives the release lever 562 to move. The release lever 562 is connected to the wedge release linkage 563 set at the non-wedge-tight ends of the two wedge-shaped locking sliders. The wedge release linkage 563 can form a release beam or fork with two synchronous pulling parts. The two synchronous pulling parts act on the wedge release shoulders on the first wedge-shaped locking slider 531 and the second wedge-shaped locking slider 541, respectively. When the release drive 561 is in the locking working position, the wedge release linkage 563 and the two wedge-shaped locking sliders retain a follow-up margin that does not hinder their slight self-amplifying force movement. Therefore, the release drive itself does not bear the normal welding overturning load.

[0047] When the release is executed, the release lever 562 drives the wedge retraction linkage 563 to overcome the pre-tightening effect of the disc spring pre-tightening assembly 553 and simultaneously pulls the two wedge-shaped locking sliders toward the wedge retraction direction until both friction locking shoes form a release gap with the arc-shaped locking beam 51. The wedge tightening action that bears the welding load is designed as a mechanical self-holding or elastic pre-tightening state, and only supplies energy to the release drive when it is necessary to readjust the posture. This allows the release actuator not to bear the workpiece overturning load for a long time. At the same time, the synchronous wedge retraction can prevent one locking branch from being released while the other branch is still dragging the arc-shaped locking beam.

[0048] The tilting drive mechanism 27 includes a tilting drive motor 23, a reduction mechanism 24, a drive pinion 25, and a sector gear 26 fixedly connected to the tilting support frame 21. The tilting drive motor 23 drives the drive pinion 25 to mesh with the sector gear 26 via the reduction mechanism 24. A welded load-bearing branch is connected between the output side of the tilting support frame 21 and the lifting support seat 31. When the closed-loop bidirectional backlash-free limiting component 5 is in the load-bearing locking state, it forms an anti-overturning load transmission path spanning the drive pinion 25, the sector gear 26, and the reduction mechanism 24. The structure 27 and the inclined support frame 21 form an attitude adjustment transmission branch for changing the boat-shaped welding posture of the shrimp-shaped elbow. The arc-shaped locking beam 51, the first direction self-increasing force locking mechanism 53, the second direction self-increasing force locking mechanism 54, the reaction force bracket 52, and the radial compliant support mechanism 57 form a welding support branch that connects the inclined support frame 21 and the lifting support seat 31 and is connected in parallel with the attitude adjustment transmission branch, so that at least part of the alternating overturning load acting on the inclined support frame 21 during the rotation of the shrimp-shaped elbow with the rotation mechanism 4 is transmitted to the lifting support seat 31 through the welding support branch.

[0049] To prevent the tilting support frame 21 from suddenly rotating when the workpiece has a static overturning moment due to forced wedge removal, the control sequence of the equipment is preferably set as follows: before the release drive 561 is activated, the slewing mechanism 4 is stopped and the tilting drive motor 23 is put into a position holding or torque holding state. The tilting drive mechanism 27 temporarily takes over the current static overturning load of the workpiece. After that, unified wedge removal is performed. Only after it is confirmed that the two friction locking shoes have formed a release gap is the tilting drive motor 23 allowed to perform a new posture adjustment movement. When locking again, the tilting drive motor first maintains the current angle, releases the forced wedge removal action of the unified wedge removal release mechanism, and allows the disc spring pretensioning assembly 553 to push the two locking branches to establish basic pre-contact. Only then is the slewing mechanism 4 allowed to enter the continuous welding rotation state. The load takeover is completed in a determined order between the drive transmission branch and the independent welding support branch, rather than switching when neither branch is under load. This helps to reduce the attitude jump at the moment of locking and releasing, and enables the functional separation of the two load paths to be realized in actual mechanical operation.

[0050] This embodiment discloses a welding limiting component for a boat-shaped position of a shrimp-shaped elbow, applied in a positioner for welding a boat-shaped position of a shrimp-shaped elbow. It includes an arc-shaped locking beam 51, a reaction force bracket 52, a first-direction self-increasing force locking mechanism 53, a second-direction self-increasing force locking mechanism 54, a differential equal-load pre-tightening mechanism 55, and a radially compliant support mechanism 57. The arc-shaped locking beam 51 is used to connect to the inclined bearing frame 21 of the positioner and extends along an arc direction with the axis of the inclined rotating shaft 22 as the center of the arc. The device has a continuous inner arc working surface 511 and an outer arc working surface 512. The reaction force bracket 52 spans the inner and outer sides of the arc-shaped locking beam 51 and forms a locking cavity 520. The first direction self-increasing force locking mechanism 53 and the second direction self-increasing force locking mechanism 54 are disposed in the locking cavity 520 and have opposite wedge tightening directions, so as to respond to the load movement tendency of the arc-shaped locking beam 51 along the two opposite arc tangential directions and convert the corresponding tangential force into an additional normal locking force toward the arc-shaped locking beam 51.

[0051] The differential equal-load pre-tightening mechanism 55 acts simultaneously on the first direction self-increasing force locking mechanism 53 and the second direction self-increasing force locking mechanism 54, so that the two self-increasing force locking mechanisms maintain pre-contact with the arc-shaped locking beam 51 in the load-bearing locking state, and allow the other self-increasing force locking mechanism to maintain foundation pre-contact when one self-increasing force locking mechanism further weds in response to the tangential load in the corresponding direction.

[0052] The reaction force bracket 52 is connected to the lifting support seat 31 of the positioner via a radial compliant support mechanism 57. The radial compliant support mechanism 57 allows the reaction force bracket 52 to generate elastic compensation displacement along the local radial direction of the arc-shaped locking beam 51, and restricts the reaction force bracket 52 to generate displacement corresponding to the change of tilt posture along the local arc tangential direction of the arc-shaped locking beam 51.

[0053] The first-direction self-increasing force locking mechanism 53 includes a first wedge-shaped locking slider 531, a first friction locking shoe 532, and a first wedge-shaped guide surface 533. The second-direction self-increasing force locking mechanism 54 includes a second wedge-shaped locking slider 541, a second friction locking shoe 542, and a second wedge-shaped guide surface 543. The first wedge-shaped guide surface 533 and the second wedge-shaped guide surface 543 have opposite wedge lifting directions. The differential equal-load preload mechanism 55 includes an equal-load pressure bridge 551, a floating fulcrum 552, a disc spring preload assembly 553, a first push rod 556, and a second push rod 557. The equal-load pressure bridge 551 is swayably mounted on the reaction frame 52 via the floating fulcrum 552, and applies preload force to the first wedge-shaped locking slider 531 and the second wedge-shaped locking slider 541 via the first push rod 556 and the second push rod 557, respectively.

[0054] The radially compliant support mechanism 57 includes a mounting base 572 and at least two sets of elastic support plates 571 connected in parallel between the mounting base 572 and the reaction force bracket 52 to form a flexible parallel guide structure that allows the reaction force bracket 52 to translate radially and constrain its arc tangential displacement. The limiting assembly also includes a unified wedge release mechanism 56, which includes a release drive member 561, a release pull rod 562, and a wedge release linkage member 563. The wedge release linkage member 563 is drively connected to the first direction self-increasing force locking mechanism 53 and the second direction self-increasing force locking mechanism 54 to synchronously switch the two self-increasing force locking mechanisms from the load locking state to the release state.

[0055] In actual use of the positioner, first stop the rotary mechanism 4 and keep the closed force ring bidirectional gapless limit assembly 5 in the released state. The release drive 561 keeps the first wedge locking slider 531 and the second wedge locking slider 541 in the wedge-retracting position through the release pull rod 562 and the wedge retraction linkage 563, so that the first friction locking shoe 532 and the second friction locking shoe 542 form an adjustment release gap with the corresponding arc working surface, respectively. Then, install the shrimp waist bend head that has been assembled and properly secured on the clamping fixture 6, adjust the clamping position and lock it, so that a reliable motion connection is formed between the workpiece and the inclined support frame 21.

[0056] At this time, the tilt drive motor 23 is started. The tilt drive motor 23 reduces the speed and increases the output torque through the reduction mechanism 24. Then, the active pinion 25 drives the sector gear 26 and the tilt support frame 21 to rotate around the tilt shaft 22. At the same time, the arc-shaped locking beam 51 passes through the already released locking cavity 520 along its own arc direction until the current weld seam to be welded reaches the predetermined boat-shaped inclination angle. The tilt drive motor 23 then enters the position holding state and starts the lifting drive motor 32, so that the lifting screw 34 drives the lifting support seat 31 to move along the lifting guide mechanism 35, so that the geometric center of the current weld seam to be welded and the rotation axis of the rotation mechanism 4 reach the specified equal height and coaxial state.

[0057] After positioning is completed, the tilt drive motor 23 continues to maintain the current angle, the release drive component 561 releases the forced wedge release, and the disc spring pretension assembly 553 pushes the equal load bridge 551. The equal load bridge 551, through the first push rod 556 and the second push rod 557 respectively, causes the first wedge-shaped locking slider 531 and the second wedge-shaped locking slider 541 to move in the pre-locking direction until the first friction locking shoe 532 and the second friction locking shoe 542 both form basic pre-contact with the arc-shaped locking beam 51. If the arc-shaped locking beam has a slight radial position deviation at this locking position, the reaction force bracket 52 automatically moves along the local radial direction to adapt to the deviation through the elastic bending of the elastic support plate 571, without the need for manual adjustment of the two friction locking shoes separately.

[0058] After confirming that the limit component has entered the load-bearing locking state, the rotary drive motor 41 is started. The rotary drive motor 41 drives the lifting adjustment mechanism 3, the tilt adjustment mechanism 2 and the workpiece to rotate continuously around the rotary axis corresponding to the current circumferential weld seam via the rotary reduction mechanism 42, the rotary drive gear 43 and the rotary bearing 44. At the same time, the welding torch set at the predetermined welding position continuously welds the current circumferential weld seam. During the rotation process, when the eccentric mass of the workpiece forms the overturning moment in the first direction, the first direction self-increasing force locking mechanism 53 automatically becomes the main load-bearing branch and further weds as the tangential load in the first direction increases, while the second direction self-increasing force locking mechanism 54 maintains the basic pre-contact. As the workpiece continues to rotate, the overturning moment gradually decreases, crosses zero and reverses, the additional wedging effect in the first direction decreases and the second direction self-increasing force locking mechanism 54, which has already made pre-contact, directly enters the self-increasing force bearing, thereby continuously completing the force transfer between the two directions.

[0059] After the current circumferential weld is completed, the welding and rotation mechanism 4 is stopped first. Then, the tilt drive motor 23 is put into position holding or torque holding state to take over the current static overturning load. Then, the release drive component 561 is activated and the two wedge-shaped locking sliders are pulled out of the force-increasing area through the wedge retraction linkage component 563 until the two friction locking shoes form a release gap with the arc-shaped locking beam. Then, the tilt drive mechanism 27 readjusts the tilt angle of the next circumferential weld to be welded and completes the new center alignment with the lifting adjustment mechanism 3. After that, the two-way foundation pre-contact is re-established and the next continuous rotation welding is started. This process is repeated until the welding of each circumferential weld of the shrimp waist bend is completed.

[0060] In summary, each welding cycle completes the load path switching in the following sequence: limit release, tilt adjustment, lifting and centering, drive holding, double-sided pre-contact, limit branch connection, continuous rotary welding, drive reconnection, and synchronous wedge withdrawal. This ensures that the continuous low-resistance movement required in the posture adjustment stage and the bidirectional high-stiffness load required in the welding stage are respectively borne by suitable structures, and that the load-bearing body is always present during the switching between load paths to avoid an unconstrained state.

[0061] As a further implementation, for large-mass or wide-axial-width curved elbows, a set of closed-loop bidirectional gapless limiting components 5 can be set on each of the two axial sides of the inclined bearing frame 21 along the inclined shaft 22. The arc-shaped locking beams of the two limiting components have the same center and are released synchronously by the same release drive system or controlled by two synchronous actuators respectively, so that the overturning load forms a more symmetrical support on both sides of the inclined bearing frame. For equipment with smaller loads, a single-sided limiting component can be used, and the torsional stiffness of the arc-shaped locking beam and the reaction force bracket can be increased to meet the design requirements. In addition to generating the main overturning moment around the inclined shaft, large workpieces may also generate torsional loads on the inclined bearing frame due to the axial center of mass offset. By setting the components symmetrically on both sides, the axial distance between the reaction force line and the workpiece load center can be shortened, thereby further reducing the additional torsional deformation of the inclined bearing frame itself, without changing the core working relationship of bidirectional pre-contact, self-increasing force locking and load path separation of the present invention.

[0062] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A welding positioner for a shrimp-shaped bend, comprising a fixed frame (1), a rotary mechanism (4), a lifting adjustment mechanism (3), a tilt adjustment mechanism (2), and a clamping fixture (6) for clamping the shrimp-shaped bend. The rotary mechanism (4) is mounted on the fixed frame (1), the lifting adjustment mechanism (3) is mounted on the rotary mechanism (4), and the tilt adjustment mechanism (2) is mounted on the lifting adjustment mechanism (3). The tilt adjustment mechanism (2) comprises a tilt support frame (21), a tilt rotating shaft (22), and a tilt drive mechanism (27) for driving the tilt support frame (21) to rotate around the tilt rotating shaft (22). The lifting adjustment mechanism (3) comprises a lifting support seat (31) for supporting the tilt adjustment mechanism (2). The machine is characterized in that: A closed-loop bidirectional gapless limiting assembly (5) is provided between the inclined bearing frame (21) and the lifting bearing seat (31). The closed-loop bidirectional gapless limiting assembly (5) includes an arc-shaped locking beam (51), a reaction force bracket (52), a first-direction self-increasing force locking mechanism (53), a second-direction self-increasing force locking mechanism (54), a differential equal load pre-tightening mechanism (55), and a radial compliant support mechanism (57). The arc-shaped locking beam (51) is fixedly connected to the inclined bearing frame (21) and extends along the arc direction with the axis of the inclined rotating shaft (22) as the center of the arc. The arc-shaped locking beam (51) has an inner arc working surface (511) and an outer arc working surface (512) that extend continuously along its arc direction. The reaction force bracket (52) spans the inner and outer sides of the arc-shaped locking beam (51) and forms a locking cavity (520) for the arc-shaped locking beam (51) to move relative to each other along the arc direction. The first direction self-increasing force locking mechanism (53) and the second direction self-increasing force locking mechanism (54) are disposed in the locking cavity (520) and correspond to the outer arc working surface (512) and the inner arc working surface (511) respectively. The first direction self-increasing force locking mechanism (53) and the second direction self-increasing force locking mechanism (54) have opposite wedging directions. When the arc-shaped locking beam (51) tends to move relative to the reaction force frame (52) along the first arc tangential direction, the first direction self-increasing force locking mechanism (53) converts the tangential force it bears into an additional normal locking force toward the arc-shaped locking beam (51). When the arc-shaped locking beam (51) tends to move along the second arc tangential direction opposite to the first arc tangential direction, the second direction self-increasing force locking mechanism (54) converts the tangential force it bears into an additional normal locking force toward the arc-shaped locking beam (51). The differential equal load pre-tightening mechanism (55) acts simultaneously on the first direction self-increasing force locking mechanism (53) and the second direction self-increasing force locking mechanism (54), so that the two maintain pre-contact with the corresponding outer arc working surface (512) and inner arc working surface (511) respectively in the load-bearing locking state, and allow the other self-increasing force locking mechanism to maintain basic pre-contact when one of the self-increasing force locking mechanisms further weds in response to the tangential load in the corresponding direction; The reaction force bracket (52) is connected to the lifting support seat (31) through a radial compliant support mechanism (57). The radial compliant support mechanism (57) allows the reaction force bracket (52) to generate local radial elastic compensation displacement along the arc-shaped locking beam (51) at the locking position of the reaction force bracket (52), and restricts the reaction force bracket (52) from generating displacement corresponding to the tilting posture change of the tilting support frame (21) along the local arc tangent of the arc-shaped locking beam (51). The tilting drive mechanism (27) and the tilting support frame (21) form an attitude adjustment transmission branch for changing the boat-shaped welding posture of the shrimp waist bend. The arc-shaped locking beam (51), the first direction self-increasing force locking mechanism (53), the second direction self-increasing force locking mechanism (54), the reaction force bracket (52), and the radial compliant support mechanism (57) form a welding support branch that connects the tilting support frame (21) and the lifting support seat (31) and is connected in parallel with the attitude adjustment transmission branch, so that at least part of the alternating overturning load acting on the tilting support frame (21) during the rotation of the shrimp waist bend with the rotation mechanism (4) is transmitted to the lifting support seat (31) through the welding support branch.

2. The shrimp-shaped bend head boat-shaped position welding positioner according to claim 1, characterized in that: The first directional self-increasing force locking mechanism (53) includes a first wedge-shaped locking slider (531), a first friction locking shoe (532), and a first wedge-shaped guide surface (533) disposed on the reaction force frame (52). The first friction locking shoe (532) is disposed on the side of the first wedge-shaped locking slider (531) facing the outer arc working surface (512). The second directional self-increasing force locking mechanism (54) includes a second wedge-shaped locking slider (541), a second friction locking shoe (542), and a first wedge-shaped guide surface (533) disposed on the reaction force frame (52). Two wedge-shaped guide surfaces (543), the second friction locking shoe (542) is disposed on the side of the second wedge-shaped locking slider (541) facing the inner arc working surface (511), the first wedge-shaped guide surface (533) and the second wedge-shaped guide surface (543) have opposite wedge lifting directions relative to the local arc tangential of the arc-shaped locking beam (51), so that the first wedge-shaped locking slider (531) and the second wedge-shaped locking slider (541) respond to the arc tangential force in opposite directions and generate an increased pressing displacement toward the arc-shaped locking beam (51).

3. The shrimp-shaped bend head boat-shaped position welding positioner according to claim 2, characterized in that: The differential equal-load preload mechanism (55) includes an equal-load pressure bridge (551), a floating fulcrum (552), a disc spring preload assembly (553), a first push rod (556), and a second push rod (557). The equal-load pressure bridge (551) is swayably mounted on the reaction frame (52) via the floating fulcrum (552). The first force-bearing end (554) of the equal-load pressure bridge (551) acts on the first wedge-shaped locking slider (531) via the first push rod (556). 1) The second force-bearing end (555) acts on the second wedge-shaped locking slider (541) through the second push rod (557). The disc spring pre-tightening assembly (553) applies a pre-tightening force to the equal load bridge (551), so that the first friction locking shoe (532) and the second friction locking shoe (542) maintain pre-contact at the same time, and the equal load bridge (551) can swing around the floating fulcrum (552) with the relative displacement difference between the first wedge-shaped locking slider (531) and the second wedge-shaped locking slider (541).

4. The shrimp-shaped bend head boat-shaped position welding positioner according to claim 3, characterized in that: The radial compliant support mechanism (57) includes a mounting base (572) and at least two sets of parallel elastic support plates (571). The mounting base (572) is fixed to the lifting bearing base (31). The elastic support plates (571) are connected between the mounting base (572) and the reaction force bracket (52) and form a flexible parallel guide structure. The arrangement of the elastic support plates (571) enables the reaction force bracket (52) to generate compensated translation through elastic bending along the local radial direction of the arc-shaped locking beam (51), and makes the load of the local arc tangential direction of the arc-shaped locking beam (51) mainly transmitted along the high stiffness direction of the elastic support plates (571).

5. The shrimp-shaped bend head boat-shaped position welding positioner according to claim 4, characterized in that: The reaction force bracket (52) is a C-shaped frame spanning the inner arc working surface (511) and the outer arc working surface (512). The first friction locking shoe (532) and the second friction locking shoe (542) are arranged opposite each other in the local radial direction along the arc-shaped locking beam (51), so that the foundation pre-tightening normal force and its reaction force applied by the first friction locking shoe (532) and the second friction locking shoe (542) to the arc-shaped locking beam (51) are closed at least partially through the inside of the reaction force bracket (52), while the arc tangential bearing reaction force applied by the arc-shaped locking beam (51) to the reaction force bracket (52) is transmitted to the lifting bearing seat (31) through the radial compliant support mechanism (57).

6. The shrimp-shaped bend head boat-shaped position welding positioner according to claim 5, characterized in that: The closed-loop bidirectional gapless limiting assembly (5) further includes a unified wedge release mechanism (56). The unified wedge release mechanism (56) includes a release drive (561), a release lever (562) connected to the release drive (561), and a wedge release linkage (563) connected to the release lever (562). The wedge release linkage (563) is in transmission cooperation with the first wedge locking slider (531) and the second wedge locking slider (541) respectively, so that when the release drive (561) performs the release action, it drives the two wedge locking sliders to exit their respective force-increasing wedge positions, so that the first friction locking shoe (532) and the second friction locking shoe (542) form a release gap with the corresponding arc working surface for the arc locking beam (51) to perform posture adjustment movement.

7. The shrimp-shaped bend head boat-shaped position welding positioner according to claim 6, characterized in that: The tilting drive mechanism (27) includes a tilting drive motor (23), a reduction mechanism (24), a drive pinion (25), and a sector tooth (26) fixedly connected to the tilting support frame (21). The tilting drive motor (23) drives the drive pinion (25) and the sector tooth (26) to mesh and transmit power through the reduction mechanism (24). The welded support branch is connected between the output side of the tilting support frame (21) and the lifting support seat (31). When the closed force ring bidirectional gapless limit assembly (5) is in the load locking state, it forms an anti-overturning load transmission path that crosses the drive pinion (25), the sector tooth (26), and the reduction mechanism (24).

8. A boat-shaped position welding limiting component for a shrimp-shaped bend, used in a boat-shaped position welding positioner as described in any one of claims 1-7, characterized in that: The limiting component is a closed force ring type bidirectional gapless limiting component (5).

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