Welding gun holder for welding robot

Abstract

The application discloses a welding gun fixing frame for a welding robot, and belongs to the technical field of welding tooling.The welding fixing frame comprises a circular base suitable for the internal space of a workpiece, a plurality of radially telescopic slide rods arranged in an annular array on the base, a driving assembly coaxially rotatably arranged at the center of the base, a rotating part of the driving assembly connected to a top cover, a flat threaded cover and a lower suspension body through elastic damping, the flat threaded cover is engaged with the slide rods to drive the telescopic movement of the slide rods to realize the centering of the workpiece, a central shaft in the rotating part is connected to a screw rod through a gear assembly, the screw rod is threadedly connected to a slide pipe, a clamping seat for clamping a welding gun is arranged on the slide pipe through a hinge shaft, a driven gear of the hinge shaft is engaged with a guide rack parallel to the slide pipe to realize the movement and angle adjustment of the welding gun.The welding gun fixing frame for the welding robot can be suitable for a plurality of workpieces requiring annular welding, realizes the linkage of the centering and the positioning of the welding gun, is accurate in positioning, simple in operation, stable in transmission and capable of protecting the workpiece.

Description

Technical Field

[0001] This invention relates to the field of robotic welding fixture technology, and more specifically to a welding torch holder for a welding robot. Background Technology

[0002] In the field of welding robots, especially when butt welding rotating workpieces (i.e., welding around circular joints), precise positioning and stable fixation of the welding torch are crucial to ensuring welding quality. Existing welding torch holders are mostly fixed structures, offering poor versatility in practical use. Each time the workpiece size is changed, a corresponding holder must be disassembled and replaced to ensure the welding torch is positioned correctly within the workpiece, resulting in cumbersome and inefficient operation. While robotic welding offers greater flexibility, for butt welding of rotating bodies, although the robotic arm's degrees of freedom are sufficient, its dimensions, especially its length, still require specific design, undoubtedly leading to excessively high costs. Meanwhile, existing fixing frames often require a multi-step operation to center the workpiece and position the welding torch. First, the workpiece is centered and fixed using additional tooling, then the position and angle of the welding torch are adjusted to align with the welding bevel. This complex process makes positioning accuracy susceptible to human error, making it difficult to guarantee precise alignment between the welding torch and the workpiece joint bevel. This can easily lead to problems such as welding misalignment and uneven welds, especially when welding items such as… Figure 1 When working with a type of workpiece as shown, the joint has a structure groove similar to an annular groove, making it difficult for the welding torch head held by the transmission fixing frame to enter the structure groove. If we rely solely on the intelligent movement of the robotic arm, as mentioned earlier, it still lacks universality for workpieces with large size and structural differences, and setting up an additional robotic arm still has the problem of excessive cost. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a welding torch holder for welding robots, so as to solve the problem in the prior art that when a rotating workpiece with a structural groove is welded and fixed, the welding torch cannot rely on a traditional welding torch holder to complete the positioning of the torch head and the workpiece joint.

[0004] This invention is achieved through the following technical solution: a welding torch holder for a welding robot, comprising a circular base and a plurality of sliding rods arranged in a ring array around the center of the base. The base can enter the workpiece in a direction parallel to the axial direction of the workpiece to be welded. The sliding rods are slidably installed radially within the base. A drive assembly is coaxially rotatably mounted within the base. The drive assembly includes a rotating part coaxially rotatably mounted within the base, with its upper and lower sides located outside the upper and lower surfaces of the base, respectively. A central shaft is coaxially rotatably mounted within the rotating part. The bottom end of the central shaft is connected to one end of a screw installed radially along the base. The other end of the screw is threadedly located inside the slide tube. A positioning rod for contacting the inner wall of the workpiece is fixed coaxially at the end of the slide tube. A clamping seat for fixing the welding gun is hinged to the slide tube near the positioning rod via a hinge shaft. The hinge shaft is set perpendicular to the slide tube and a driven gear is fixed coaxially at its end. The driven gear meshes with the guide rack below it through a reversing gear. The guide rack is set parallel to the slide tube and one end is fixedly connected to the lower part of the rotating part. When the rotating part rotates coaxially with the base, all the sliding rods extend synchronously from the side of the base and eventually contact the inner wall of the workpiece to achieve the centering and installation of the workpiece. When the rotating part continues to rotate, the central axis begins to rotate asynchronously with respect to the rotating part, causing the screw to rotate. This drives the welding torch to move against the inner wall of the workpiece, while its tip rotates towards the inner side of the workpiece. When the positioning rod contacts the inner wall of the workpiece, the tip reaches the predetermined welding bevel.

[0005] Furthermore, the rotating part also includes a top cover, a flat threaded cover, and a lower suspension body arranged sequentially from top to bottom. The top cover and the lower suspension body are arranged opposite to each other, and the flat threaded cover is rotatably connected between them by an elastic element with elastic damping. The bottom end of the flat threaded cover is rotatably installed in an annular mounting groove on the upper surface of the base and engages with the flat thread on the slide rod. The central shaft is rotatably installed in the lower suspension body. The central shaft is rotated by a gear assembly, which is installed in the circular cavity formed by the flat threaded cover, the top cover, and the lower suspension body.

[0006] Furthermore, the bottom of the top cover is in contact with a cylindrical spring coaxially disposed on the top surface of the planar threaded cover; the top surface of the lower suspension has a raised annular slide rail for the planar threaded cover to be rotatably mounted; the upper and lower ends of the central shaft are located inside the top cover and the lower suspension respectively, so as to connect the top cover, the planar threaded cover and the lower suspension into one unit.

[0007] Furthermore, the top surface of the planar threaded cap has a built-in contact ring that is coaxially connected to the cylindrical spring.

[0008] Furthermore, a deep groove ball bearing is installed inside the top cover, and the top end of the central shaft is fixedly installed in the inner ring of the deep groove ball bearing. The top end of the deep groove ball bearing is provided with a cap, which is threadedly fixed flush with the top surface of the top cover.

[0009] Furthermore, the gear assembly includes an internal gear, a variable speed gear, and a central gear that mesh sequentially. The internal gear is coaxially fixed to the wall of the central hole of the planar threaded cover, the variable speed gear is rotatably mounted in the circular cavity, and the central gear is coaxially fixed to the central shaft.

[0010] Furthermore, the lower part of the lower suspension body is an L-shaped right-angle bent tube structure; the bottom end of the central shaft is located inside the bent tube structure and is fixed with a driving bevel gear, and the end of the screw is rotatably installed inside the free end of the bent tube structure and is fixed with a driven bevel gear, with the two bevel gears meshing.

[0011] Furthermore, the part where the guide rack is fixedly connected to the lower part of the rotating body is the bent tube structure, and a guide rack is provided on each side of the slide tube, and a driven gear and a reversing gear are fixed at each end of the hinge shaft.

[0012] Furthermore, the positioning rod is a telescopic rod with adjustable length. Its adjustment length must meet the requirement that, after the workpiece is centered, the distance between the free end face of the positioning rod and the nozzle of the welding torch in the radial direction of the base is equal to the distance between the position of the nozzle of the welding torch and the inner wall of the workpiece in the radial direction during welding.

[0013] Furthermore, the free end of the positioning rod is provided with a freely rolling steel ball with a smooth surface for rolling contact with the inner wall of the workpiece.

[0014] The beneficial effects of this invention are as follows: This welding torch holder for welding robots does not require the robot's robotic arm to have good dimensional versatility, and it does not rely on the robotic arm to complete the final positioning of the welding torch. Essentially, the robotic arm only places the welding torch into the workpiece, but does not need to move the welding torch to the set welding position relative to the workpiece. Therefore, it makes the robotic arm more versatile. Furthermore, for workpieces with significantly different sizes and structures, a correspondingly sized welding torch holder can be designed and directly installed on the robotic arm in a more economical way. This utilizes the intelligent control function of the robotic arm more economically and practically, without the need for a costly replacement of the entire robotic arm; it is equivalent to replacing only a simple hand (this welding torch holder). In addition, this welding torch holder can also center the workpiece. There is no need to set up an additional centering mechanism to allow the workpiece and welding torch to rotate relative to each other. The welding torch holder itself can achieve the centering installation of the workpiece, ensuring that the welding torch can accurately weld a full circle around the workpiece joint.

[0015] Specifically, this welding torch holder features a design where the sliding rod can freely extend and retract radially along the base, allowing for flexible adaptation to workpieces of different inner diameters without the need to disassemble or replace the holder, significantly improving the equipment's versatility and operational efficiency. Simultaneously, the positioning rod employs an adjustable telescopic structure, allowing for length adjustments based on workpiece thickness and bevel dimensions, ensuring the welding torch head accurately reaches the preset welding position, further expanding its adaptability. Furthermore, the invention utilizes an elastic damping rotational connection design in the drive assembly to achieve coordinated control of workpiece centering and welding torch positioning. Rotating the rotating part completes workpiece centering, and continued rotation drives the welding torch to move and adjust its angle, eliminating the need for separate steps, sharing power equipment, and simplifying the operation process. Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the docking structure of a rotary workpiece with a structural groove. Figure 2 This is a schematic diagram of the welding torch holder for a welding robot in this invention, which drives the welding torch and the workpiece to achieve a relative welding working position. Figure 3 This is a schematic diagram of the welding torch holder used in a welding robot before the welding torch has reached the welding position when the workpiece is centered. Figure 4 It is a flat threaded cap; Figure 5 This is a schematic diagram of the lower suspension structure; Figure 6 This is a partial schematic diagram of the slide bar; Figure 7 for Figure 2 Enlarged view of point A in the middle.

[0017] In the diagram: 1. Workpiece to be welded; 101. Welding bevel; 102. Structural groove; 2. Welding torch; 3. Base; 4. Slide rod; 5. Guide bar; 6. Central shaft; 7. Rotating part; 701. Top cover; 702. Flat threaded cover; 703. Lower suspension; 703. Circular guide rail; 70301. Bent pipe structure; 70302. Screw; 8. Slide pipe; 9. Clamp; 10. Driven gear; 11. Variable direction gear; 12. Guide rack; 13. Internal gear; 14. Speed ​​change gear; 15. Central gear; 16. Driving bevel gear; 17. Driven bevel gear; 18. Cylindrical spring; 19. Contact ring; 20. Deep groove ball bearing; 21. Cover; 22. T-bolt; 23. Steel ball; 24. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] Please see Figures 2-3 This invention provides a technical solution: a welding torch holder for a welding robot. The welding torch holder includes a circular base 3, the size of which is adapted to the internal space of the workpiece 1 to be welded, allowing it to smoothly enter the workpiece along a direction parallel to its axial direction. Several sliding rods 4 are arranged in a circular array around the center of the base 3. Each sliding rod 4 is slidably mounted inside the base 3 along its radial direction and can freely extend and retract radially to accommodate workpieces of different inner diameters. A drive assembly is coaxially rotatably mounted at the center of the base 3. This drive assembly includes a rotating part 7, the upper and lower sides of which extend beyond the upper and lower surfaces of the base 3, facilitating rotation by an operator or drive mechanism. Generally, a central shaft 6 is coaxially rotatably mounted inside the rotating part 7. The bottom end of the central shaft 6 is connected to one end of a screw 8 arranged radially along the base 3. When the central shaft 6 rotates, it causes the screw 8 to rotate as well. Figure 2In this embodiment, the other end of the screw 8 is threaded into the interior of a slide tube 9. The end of the slide tube 9 is coaxially fixed with a positioning rod. The positioning rod is used to contact and position the workpiece's inner sidewall to limit the rotation angle of the welding torch 2, i.e., to control the welding torch 2 to finally reach the corresponding welding position. Specifically, a clamping seat can be fixed near the positioning rod of the slide tube 9 via a hinge shaft. This clamping seat is used to fix the welding torch 2. The clamping seat is located inside the slide tube 9 and can rotate freely with the hinge shaft. The arrangement direction of the hinge shaft is perpendicular to the axis of the slide tube 9. The hinge shaft is hinged to the slide tube 9, and a driven gear 11 is coaxially fixed at the end of the hinge shaft that protrudes from the sidewall of the slide tube 9. The driven gear 11 meshes with the reversing gear 12 below, and the reversing gear 12 meshes with a guide rack 13. The arrangement direction of the guide rack 13 is parallel to the slide tube 9, and one end of it is fixedly connected to a certain part of the lower part of the rotating part 7 to achieve a cantilevered installation of the guide rack 13. In use, the rotating part 7 is rotated to make it coaxial with the base 3. During this process, all the sliding rods 4 extend radially along the base 3 simultaneously until the ends of all the sliding rods 4 contact the inner wall of the workpiece, thus achieving coaxial setting of the workpiece and the base 3, or rather, the fixed frame. This allows the workpiece to rotate when the welding torch 2 moves into position, enabling the welding torch 2 to automatically weld around the corresponding joint, thereby achieving welding and fixing of the joint at the workpiece joint. For example, the joint is generally processed with... Figures 1-3 When making the bevel as shown, the nozzle of the welding torch 2 should be positioned close to the predetermined position of the bevel for welding.

[0022] As a necessary condition, in specific implementation, when the base 3 and the workpiece are coaxial, the rotating part 7 on the base 3 must continue to rotate. At this time, the central shaft 6 begins to rotate asynchronously relative to the rotating part 7 (there is a speed difference). That is, the central shaft 6 rotates relative to the rotating part 7, which allows the screw 8 to rotate. Initially, the central shaft 6 and the screw 8 rotate as a unit with the rotating part 7, so the screw 8 does not rotate on its own but only revolves around the axis of the base 3. When the aforementioned speed difference occurs, the screw 8 rotates, which drives the slide tube 9, which is threaded to it, to move along a certain radial direction of the base 3 towards the inner wall of the workpiece under the constraint of the guide rack 13. At the same time, the guide rack 13, which supports and installs the driven gear 11, also causes the driven gear 11 to roll forward, and drives the driven gear 11 to rotate through the reversing gear 12, thereby driving the hinge shaft and the clamping seat to rotate, causing the welding torch 2 to rotate. Figure 2As shown, the welding torch 2 rotates clockwise, causing its tip to rotate and approach the inner side of the workpiece. When the positioning rod is fully in contact with the inner wall of the workpiece, the tip of the welding torch 2 enters the structural groove of the workpiece and reaches the preset welding bevel 101, completing the positioning preparation of the welding torch 2. Finally, the workpiece is clamped at this time using existing tooling such as chucks, causing the workpiece to rotate. That is, the workpiece actually rotates around the axis of the welding torch 2 fixing frame, which is equivalent to the welding torch 2 making a circular motion relative to the workpiece, automatically and accurately welding a circle around the joint of the workpiece.

[0023] Based on the above implementation structure, more specifically, please refer to the figure. This rotating part 7 consists of three parts arranged from top to bottom: a top cover 701, a flat threaded cover 702, and a lower suspension body 703. The top cover 701 and the lower suspension body 703 are arranged coaxially and opposite to each other. The flat threaded cover 702 is installed between the top cover 701 and the lower suspension body 703. The flat threaded cover 702 and the top cover 701 are connected by an elastic element for elastic damping rotation, or similarly, the flat threaded cover 702 and the lower suspension body 703 are connected by elastic damping rotation. The purpose is to ensure that the three components are combined into one unit under normal conditions due to the elastic force of the elastic element, and that when the external torque does not reach a certain level... The three components rotate as a whole, meaning the entire rotating part 7 is in a unified state, rotating axially around the base 3. However, when the external torque reaches a certain value, the top cover 701 and the lower suspension 703 can rotate and slip together relative to the planar threaded cover 702. For example, when all three sliding rods 4 are in contact with the inner wall of the workpiece to achieve centering, continuing to rotate the rotating part 7 will prevent the sliding rods 4 from moving further, so the planar threaded cover 702 will stop rotating. Continuing to rotate will result in a greater actual torque, which in turn causes the top cover 701 and the lower suspension 703 to rotate coaxially relative to the planar threaded cover 702. This is the structural principle and characteristic of the elastic damping rotation connection described above. In specific manufacturing, the structures of the planar threaded cover 702 and the lower suspension 703 are as follows: Figure 4 and Figure 5As shown, during installation, the bottom end of the flat threaded cover 702 is rotatably mounted in the annular mounting groove on the upper surface of the base 3. The annular mounting groove is coaxial with the base 3, and the bottom surface of the flat threaded cover 702 is provided with a flat thread. This flat thread meshes with the corresponding flat thread structure on the slide rod 4, ensuring that the rotating part 7 can drive the slide rod 4 to extend and retract radially when rotating. Specifically, the flat thread structure can be a guide bar 5 with a rectangular cross-section fixed to the upper side of the slide rod 4, and the top surface of the guide bar 5 is provided with a flat thread. The aforementioned central shaft 6 is rotatably mounted inside the lower suspension body 703. This central shaft 6 rotates through a set of gear assemblies. The gear assembly is installed as a whole in a circular cavity formed by the top cover 701, the flat threaded cover 702, and the lower suspension body 703. The circular cavity is coaxial with the base 3, which can seal and protect the gear assembly, preventing damage to the gear assembly from spatter, dust, etc. generated during welding, and ensuring the stability of transmission.

[0024] In this embodiment, as Figure 2 , Figure 7 As shown, the above-mentioned elastic damping rotational connection is detailed as follows: A cylindrical spring 19 is provided between the bottom of the top cover 701 and the top surface of the planar threaded cover 702. The cylindrical spring 19 is coaxially arranged with the base 3, the top cover 701, and the planar threaded cover 702, and the two ends of the cylindrical spring 19 are respectively pressed into contact with the bottom of the top cover 701 and the top surface of the planar threaded cover 702, thereby realizing the elastic damping connection between the top cover 701 and the planar threaded cover 702. Similarly, the above structure can also be provided between the bottom of the planar threaded cover 702 and the top surface of the lower suspension 703 to better realize the elastic damping rotational connection. In specific manufacturing, a raised annular slide rail can be provided on the top surface of the lower suspension 703. The annular slide rail is coaxial with the lower suspension 703 for better rotational connection. The bottom end of the planar threaded cover 702 is provided with an annular mounting groove that matches the annular slide rail. The planar threaded cover 702 is rotatably mounted on the annular slide rail through the annular mounting groove to realize the rotational engagement with the lower suspension 703. Regarding the central axis 6 in this embodiment, its general structure can be as follows: Figure 7 As shown, its upper and lower ends extend into the interior of the top cover 701 and the lower suspension 703, respectively. Through the through connection of the central shaft 6, it not only mounts the central shaft 6 but also connects the top cover 701, the flat threaded cover 702, and the lower suspension 703 into a single unit. This ensures both the structural integrity of the rotating part 7 and the coaxiality of the central shaft 6 during rotation, preventing problems such as offset or jamming. Of course, in practice, additional features can be provided on the end face of the flat threaded cover 702, such as... Figure 7The T-bolt 23 shown is configured such that the nut of the T-bolt 23 is slidably installed in the annular guide groove on the flat thread end face, and the stud of the T-bolt 23 is located in the threaded hole inside the top cover 701, etc. The nut tightened at the end of the stud also presses an elastic element, such as an elastic flat washer, so that the above-mentioned elastic damping rotational connection can also be achieved.

[0025] like Figure 7 As shown, a contact ring 20 is built into the top surface of the flat threaded cover 702. The contact ring 20 is coaxially arranged with the cylindrical spring 19, and the bottom end of the cylindrical spring 19 is fixedly connected to the contact ring 20. The contact ring 20 is made of wear-resistant and pressure-resistant material, which can increase the contact area between the cylindrical spring 19 and the flat threaded cover 702, avoid wear and dents on the top surface of the flat threaded cover 702 caused by long-term compression of the cylindrical spring 19, and at the same time, can make the elastic force of the cylindrical spring 19 evenly transmitted to the flat threaded cover 702, ensuring the damping stability of the flat threaded cover 702 when rotating, and preventing rotation jamming or loosening caused by uneven elastic force. Inside the top cover 701, a deep groove ball bearing 21 is installed. The deep groove ball bearing 21 is coaxially arranged with the top cover 701 and the central shaft 6. The top end of the central shaft 6 is fixedly installed in the inner ring of the deep groove ball bearing 21. The deep groove ball bearing 21 enables the rotational engagement between the central shaft 6 and the top cover 701, reducing the friction during the rotation of the central shaft 6 and ensuring its smooth rotation. It also serves to connect the top cover 701 and the lower suspension 703. In addition, a cover 22 can be provided at the top end of the deep groove ball bearing 21. The cover 22 is installed on the top cover 701 by thread, and the top surface of the cover 22 is flush with the top surface of the top cover 701. This provides a sealing protection for the deep groove ball bearing 21, preventing welding spatter, dust, etc. from entering the bearing and affecting its service life. It also ensures the flatness of the top end of the rotating part 7, avoiding protruding structures that may affect operation or interfere with the workpiece. Similarly, the lower end of the central shaft 6 can also adopt the above installation method.

[0026] In practice, the gear assembly comprises three parts: an internal gear 14, a transmission gear 15, and a central gear 16. These three parts mesh sequentially to transmit power. When the slide rod 4 is not in contact with the inner wall of the workpiece, there is no relative rotational meshing between these gears; they all rotate integrally on the base 3 along with the rotating part 7. During installation, if... Figure 7The internal gear 14 is coaxially fixed to the wall of the central hole of the flat threaded cover 702 and rotates synchronously with the flat threaded cover 702. Ideally, the internal gear 14 is integrally formed with the flat threaded cover 702. The speed-changing gear 15 is rotatably mounted on a shaft within the circular cavity formed by the top cover 701, the flat threaded cover 702, and the lower suspension 703, and also assists in connecting the top cover 701 and the lower suspension 703. One side of the speed-changing gear 15 meshes with the internal gear 14, and the other end meshes with the central gear 16, thus changing the speed. The central gear 16 is coaxially fixed to the central shaft 6 and can drive the central shaft 6 to rotate under the drive of the speed-changing gear 15, thereby enabling the central gear 16 to rotate within the aforementioned cylindrical cavity, i.e., to rotate relative to the lower suspension 703 within the lower suspension 703. This allows the screw 8 to rotate via a mechanism such as gear transmission, ultimately driving the welding torch 2 to move and rotate for positioning.

[0027] In this embodiment, the lower part of the lower suspension 703 adopts an L-shaped right-angle bent tube structure 70302. The corner of the bent tube structure 70302 is rounded to avoid stress concentration and facilitate the rotational installation of the screw 8. The bottom end of the central shaft 6 extends into the interior of the bent tube structure 70302, and a driving bevel gear 17 is fixedly installed at the bottom end of the central shaft 6 to form the aforementioned gear transmission form. One end of the screw 8 is rotatably installed inside the free end of the bent tube structure 70302, and a driven bevel gear 18 is fixedly installed at this end of the screw 8. The driving bevel gear 17 and the driven bevel gear 18 mesh with each other to achieve vertical reversal of power. When the central shaft 6 rotates (this refers to rotation relative to the lower suspension 703, i.e., rotation within the lower suspension 703, rather than rotation together with the lower suspension 703), it drives the active bevel gear 17 to rotate. The active bevel gear 17 drives the driven bevel gear 18 to rotate, which in turn drives the screw 8 to rotate, thus enabling the slide tube 9 to move radially along the workpiece. This structure can make reasonable use of space, converting the axial rotation of the central shaft 6 into the radial rotation of the screw 8, ensuring a stable and reliable transmission process, and facilitating the arrangement of the screw 8 and the slide tube 9.

[0028] In this embodiment, the end of the guide rack 13 connected to the lower part of the rotating part 7 can be optionally fixed on the L-shaped bend structure 70302 of the lower suspension 703 to ensure the stability of the guide rack 13. On both sides of the slide tube 9, a guide rack 13 is fixed respectively, the two guide racks 13 are arranged symmetrically and are parallel to the axis of the slide tube 9; correspondingly, at both ends of the hinge shaft, a driven gear 11 and a reversing gear 12 are fixed respectively. The two driven gears 11 mesh with the guide racks 13 on both sides respectively, and the two reversing gears 12 mesh with the corresponding driven gears 11 respectively, improving the stability and reliability of the transmission. When the slide tube 9 moves radially along the workpiece or base 3, the driven gears 11 on both sides rotate synchronously along their respective guide racks 13, and then rotate with the hinge shaft, thereby driving the clamping seat and welding torch 2 to rotate synchronously, ensuring the smoothness and symmetry of the rotation of the welding torch 2 head, avoiding the displacement of the torch head caused by uneven force on one side, and ensuring the accuracy of reaching the position near the welding groove 101.

[0029] In this embodiment, as Figures 2-3 As shown, the positioning rod adopts an adjustable telescopic rod structure. The telescopic rod is composed of multiple nested sleeves, and its length is fixed by a locking device. Its adjustable length range can meet the welding requirements of workpieces of different specifications. Specifically, the adjusted length of the positioning rod must meet the following requirement: after the workpiece is centered, the distance between the free end face of the positioning rod and the welding torch 2 head in the radial direction of the base 3 is exactly equal to the radial distance between the welding torch 2 head and the inner wall of the workpiece when the welding torch 2 is performing the welding operation. In this way, when the free end of the positioning rod contacts and positions itself against the inner wall of the workpiece, the welding torch 2 head can accurately reach the preset welding groove 101 without additional adjustment of the welding torch 2 position, improving the efficiency and accuracy of welding positioning, and can adapt to workpieces of different thicknesses and different groove sizes.

[0030] To ensure that the centered workpiece can rotate after being clamped by a three-jaw chuck, i.e., rotate around the axis of the welding torch 2 fixing frame, it is best to... Figure 3As shown, a freely rolling steel ball 24 is provided at the free end of the positioning rod. The steel ball 24 is made of high-strength, high-wear-resistant steel, and its surface is polished to be smooth and burr-free to reduce friction. When the positioning rod contacts the inner wall of the workpiece, the steel ball 24 forms a rolling contact with the inner wall of the workpiece, which can effectively reduce the friction between the positioning rod and the inner wall of the workpiece, and prevent the inner wall of the workpiece from being scratched when the positioning rod slides on the inner wall of the workpiece. Moreover, the rolling contact method can adapt to the slight curvature changes of the inner wall of the workpiece, improving the stability of positioning. It should be noted that in use, the workpiece to be welded, which has been pre-positioned and aligned by positioning pins, can be placed on a worktable (not shown in the figure). For example, after the upper and lower cylindrical sections of the workpiece are coaxially aligned and connected by several positioning pins located inside the cylindrical walls of the two sections, the whole workpiece is placed flat on the worktable. Then, the welding torch 2 is mounted on the welding torch 2 holder (the initial position of the welding torch 2 can be set to, for example...). Figure 3 As shown in the diagram, the workpiece is first placed inside, and then the rotating part 7 rotates. For example, the top cover 701 or the flange plate fixed to its top can be rotated to rotate the entire rotating part 7. The guide bar 5 is engaged by the flat threaded cover 702 to slide out, thereby achieving the centering and installation of the workpiece relative to the fixing frame of the welding torch 2. When the top cover 701 is rotated, the gear 15 and the internal gear 14 will mesh and drive, thereby causing the central shaft 6 to rotate. The central shaft 6 drives the screw 8 to rotate through the bevel gear transmission. The screw 8 drives the welding torch 2 to move towards the inner wall of the workpiece and rotate. Finally, the torch head of the welding torch 2 reaches the designated working position of the welding bevel 101 attachment. Then, the movable three-jaw chuck or similar clamp that clamps the lower cylinder section of the workpiece is rotated to achieve the welding torch 2 to weld the seam between the two cylinder sections. When starting to clamp the workpiece and rotate it, the rotating part 7 or the top cover 701 can be reversed by a small angle first, allowing the slide rod 4 to retract, or even prevent the slide rod 4 from contacting the side wall of the workpiece, thus avoiding obstructing the workpiece's rotation. It should be noted that when the slide rod 4 is in contact with the inner side wall of the workpiece, its continued sliding is hindered. However, when the slide rod 4 retracts back into the base 3, it is not subject to this constraint. Therefore, when the rotating part 7 is rotated in the reverse direction, it can return to its integrated state and rotate as a whole, without the aforementioned obstruction. The elastic damping rotation characteristic means that the central shaft 6 will not rotate relative to the lower suspension 703, but will only rotate synchronously together, thus smoothly separating the slide rod 4 from the workpiece, so that the workpiece is not obstructed by the end of the slide rod 4 during the rotation process of welding; of course, in practice, the aforementioned steel ball 24 can also be set at the end of the slide rod 4 to reduce the friction between the workpiece and the slide rod 4 when the workpiece rotates. Even if the slide rod 4 does not reverse and separate from the side wall of the workpiece, it is still operable to allow the workpiece to be gradually welded by the welding torch 2 while it rotates.

[0031] In the above description of the present invention, it should be noted that the terms "one side," "the other side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is conventionally placed during use. These terms are used only for the convenience of describing the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0032] Furthermore, terms such as "identical" do not imply that components must be absolutely identical; minor differences are permissible. The term "perpendicular" simply means that the positional relationship between components is more perpendicular than "parallel," not that the structure must be perfectly perpendicular; a slight tilt is acceptable.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A welding torch holder for a welding robot, characterized in that: The assembly includes a circular base (3) and several sliding rods (4) arranged in a ring around the center of the base (3). The base (3) can enter the workpiece (1) in a direction parallel to the axial direction of the workpiece to be welded. The sliding rods (4) are slidably installed in the base (3) along its radial direction. A drive assembly is coaxially rotatably installed in the base (3). The drive assembly includes a rotating part (7) coaxially rotatably installed in the base (3). The upper and lower sides of the rotating part (7) are located outside the upper and lower surfaces of the base (3), respectively. A central shaft (6) is coaxially rotatably installed in the rotating part (7). The bottom end of the central shaft (6) is installed radially along the base (3). One end of a screw (8) is connected to the drive, and the other end of the screw (8) is threadedly located inside the slide tube (9). The end of the slide tube (9) is coaxially fixed with a positioning rod for contacting the inner wall of the workpiece. A clamping seat for fixing the welding gun (2) is hinged to the slide tube (9) near the positioning rod via a hinge shaft. The hinge shaft is set perpendicular to the slide tube (9) and its end is coaxially fixed with a driven gear (11). The driven gear (11) meshes with the guide rack (13) below it through a reversing gear (12). The guide rack (13) is set parallel to the slide tube (9) and one end of it is fixedly connected to the lower part of the rotating part (7). When the rotating part (7) rotates coaxially with the base (3), all the sliding rods (4) extend out of the side of the base (3) at the same time and eventually contact the inner wall of the workpiece to achieve the centering installation of the workpiece. When the rotating part (7) continues to rotate, the central shaft (6) begins to rotate asynchronously with respect to the rotating part (7) to make the screw (8) rotate. At the same time, the welding gun (2) moves against the inner wall of the workpiece, and its gun head rotates towards the inner side of the workpiece. When the positioning rod contacts the inner wall of the workpiece, the gun head reaches the predetermined welding groove (101).

2. The welding torch holder for a welding robot according to claim 1, characterized in that: The rotating part (7) further includes a top cover (701), a flat threaded cover (702), and a lower suspension (703) arranged sequentially from top to bottom. The top cover (701) and the lower suspension (703) are arranged opposite to each other, and the flat threaded cover (702) is rotatably connected between them by an elastic element. The bottom end of the flat threaded cover (702) is rotatably installed in an annular mounting groove on the upper surface of the base (3) and engages with the flat thread on the slide rod (4). The central shaft (6) is rotatably installed in the lower suspension (703). The central shaft (6) is rotated by a gear assembly, which is installed in the circular cavity formed by the flat threaded cover (702), the top cover (701), and the lower suspension (703).

3. The welding torch holder for a welding robot according to claim 2, characterized in that: The bottom of the top cover (701) is pressed into contact with a cylindrical spring (19) coaxially disposed on the top surface of the planar threaded cover (702); the top surface of the lower suspension (703) has a raised annular slide rail for the planar threaded cover (702) to be rotatably mounted; the upper and lower ends of the central shaft (6) are located inside the top cover (701) and the lower suspension (703) respectively, so as to connect the top cover (701), the planar threaded cover (702) and the lower suspension (703) into one unit.

4. The welding torch holder for a welding robot according to claim 3, characterized in that: The top surface of the planar threaded cap (702) has a contact ring (20) that is coaxially connected to the cylindrical spring (19).

5. The welding torch holder for a welding robot according to claim 3, characterized in that: A deep groove ball bearing (21) is installed inside the top cover (701). The top end of the central shaft (6) is fixedly installed in the inner ring of the deep groove ball bearing (21). The top end of the deep groove ball bearing (21) is provided with a cap (22), which is threadedly fixed flush with the top surface of the top cover (701).

6. The welding torch holder for a welding robot according to claim 2, characterized in that: The gear assembly includes an internal gear (14), a variable speed gear (15), and a central gear (16) that mesh sequentially. The internal gear is coaxially fixed on the wall of the central hole of the planar threaded cover (702). The variable speed gear (15) is rotatably mounted in the circular cavity. The central gear (16) is coaxially fixed on the central shaft (6).

7. The welding torch holder for a welding robot according to claim 6, characterized in that: The lower part of the lower suspension (703) is an L-shaped right-angle bent tube structure (70302); the bottom end of the central shaft (6) is located inside the bent tube structure (70302) and is fixed with a driving bevel gear (17); the end of the screw (8) is rotatably installed inside the free end of the bent tube structure (70302) and is fixed with a driven bevel gear (18); the two bevel gears mesh.

8. The welding torch holder for a welding robot according to claim 7, characterized in that: The guide rack (13) is fixedly connected to the lower part of the rotating body at the bent tube structure (70302), and a guide rack (13) is provided on each side of the slide tube (9), and a driven gear (11) and a reversing gear (12) are fixed at each end of the hinge shaft.

9. The welding torch holder for a welding robot according to claim 1, characterized in that: The positioning rod is a telescopic rod with adjustable length. Its adjustment length must meet the following requirement: after the workpiece is centered, the distance between the free end face of the positioning rod and the nozzle of the welding gun (2) in the radial direction of the base (3) is equal to the distance between the position of the nozzle of the welding gun (2) and the inner wall of the workpiece in the radial direction when the welding gun (2) is welding.

10. The welding torch holder for a welding robot according to any one of claims 1-9, characterized in that: The free end of the positioning rod is provided with a steel ball (24) that can roll freely. The surface of the steel ball (24) is smooth so as to make rolling contact with the inner wall of the workpiece.

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