Full position welding equipment for small diameter short straight section bend

Abstract

This application discloses an all-position welding device for small-diameter short straight-section bends, comprising a machine body, a U-shaped groove at the head of the machine body, and a rotating chassis at the head of the machine body; a head rotation transmission mechanism and a head rotation power mechanism for driving the rotating chassis to rotate on the machine body; and a head welding mechanism comprising a welding torch mounted on the rotating chassis. The advantage of this application is that it enables 360° all-position welding of small-diameter short straight-section pipes or bends.

Description

Technical Field

[0001] This application relates to the field of welding equipment technology, and in particular to a welding equipment for all-position welding of small-diameter short straight-section bends. Background Technology

[0002] Heat exchangers are typically placed in pressurized environments with corrosive media and thermal stress. Due to welding quality issues, leaks are highly likely to occur at the weld joints of heat exchanger tubes, leading to heat exchanger failure. Therefore, welding between heat exchanger tubes is a critical step in the manufacturing process. However, the dense arrangement of heat exchanger tubes and the limited space for welding make tube-to-tube welding extremely difficult, especially for small tubes with short bends. Currently available automated tube welding equipment cannot perform in-situ welding for these tubes; manual welding is inefficient and the weld quality is difficult to guarantee. Summary of the Invention

[0003] This application provides a small-diameter short straight section bend pipe all-position welding equipment, which has the advantage of being able to perform 360° all-position welding on small-diameter short straight section pipes or bends.

[0004] The above-mentioned objective of this application is achieved through the following technical solution: a small-diameter short straight section bending pipe all-position welding equipment, including a machine body, the head of the machine body having a U-shaped groove, and the head of the machine body being provided with a rotating chassis;

[0005] The machine body is provided with a head rotation transmission mechanism and a head rotation power mechanism for driving the rotating chassis to rotate on the machine body.

[0006] A head welding mechanism is provided on the rotating chassis, and the head welding mechanism includes a welding gun mounted on the rotating chassis.

[0007] Furthermore, the head rotation transmission mechanism includes a crescent-shaped gear base, a crescent-shaped spur gear, a transmission spur gear, a crescent-shaped gear upper fixing plate, a lower limit plate, and an upper limit plate. The crescent-shaped gear base is installed on the head of the machine body, the lower limit plate and the upper limit plate are fixed to the machine body, the crescent-shaped spur gear is disposed inside the crescent-shaped gear base, the crescent-shaped gear upper fixing plate is fixed on the crescent-shaped spur gear, the rotating chassis is installed on the crescent-shaped gear upper fixing plate and located above the upper limit plate, and the transmission spur gear is connected to the crescent-shaped spur gear through a planetary spur gear.

[0008] Furthermore, the head rotation power mechanism includes a rotary motor, a rotary driving bevel gear, a rotary driven bevel gear, a rotary shaft, a rotary driven spur gear, and a rotary motor mounting base. The rotary motor mounting base is mounted on the machine body. The rotary motor drives the transmission spur gear to rotate sequentially through the rotary driving bevel gear, the rotary driven bevel gear, the rotary shaft, and the rotary driven spur gear, thereby driving the rotary chassis to rotate.

[0009] Furthermore, the head welding mechanism also includes a welding mechanism base, a support frame, a welding torch fixing seat, and a wire feeding nozzle fixing block. The welding mechanism base is mounted on the rotating chassis, and the support frame is rotatably mounted on the welding mechanism base via a support frame rotation shaft. A torsion spring is provided on the support frame rotation shaft, and a welding pitch adjustment top wheel is provided on the support frame. The welding torch fixing seat and the wire feeding nozzle fixing block are mounted on the support frame, the welding torch is mounted on the welding torch fixing seat, and a wire feeding nozzle is provided on the wire feeding nozzle fixing block.

[0010] Furthermore, the support frame is also equipped with a head water cooling input terminal, a head welding negative electrode input terminal, and a head protective gas input terminal. The machine body is equipped with a water, electricity, and gas input mechanism, which is used to connect to external water, electricity, and gas, and is connected to the head water cooling input terminal, the head welding negative electrode input terminal, and the head protective gas input terminal through water pipes, wires, and gas pipes, respectively.

[0011] Furthermore, the machine body is also equipped with a wire spool, a wire feeding actuator, and a wire feeding power mechanism;

[0012] The welding wire spool is detachably mounted on the machine body and can rotate on the machine body, and welding wire is wound on the welding wire spool;

[0013] The wire feeding actuator includes a wire feeding actuator support mounted on the machine body. The wire feeding actuator support is provided with a wire inlet, a wire outlet, a drive spur gear, and a rotating door. The rotating door is rotatably mounted on the wire feeding actuator support. A rotating door fixing shaft is connected to the rotating door. A driven spur gear is provided inside the rotating door. The drive spur gear and the driven spur gear are provided with U-shaped wire grooves for the wire to pass through. The drive spur gear is connected to an input bevel gear through a bevel gear shaft.

[0014] The wire feeding power mechanism includes a wire feeding motor mounting base, a wire feeding motor, and a wire feeding bevel gear. The wire feeding motor mounting base is mounted on the machine body, and the wire feeding motor is mounted on the wire feeding motor mounting base. The wire feeding motor drives the input bevel gear to rotate through the wire feeding bevel gear.

[0015] It also includes a welding wire hose, one end of which is connected to the wire outlet nozzle and the other end of which is connected to the wire feed nozzle.

[0016] Furthermore, the machine body is also equipped with a pipe clamping mechanism, which is located below the head of the machine body and is used to fix the pipes that need to be welded.

[0017] Furthermore, it also includes a welding control system, which includes a human-machine interface touch screen and a central controller. The human-machine interface touch screen and the central controller are communicatively connected. The central controller is used to control a rotary motor, a wire feeding motor, a protective gas solenoid valve installed in the gas pipeline, a water cooling control valve installed in the water pipeline, and a welding power supply for supplying power to the equipment.

[0018] Furthermore, a ring-shaped force gauge is respectively installed at the wire inlet, wire outlet, and wire feeding nozzle. The wire feeding speed is controlled by the wire feeding motor. The wire feeding speed control method includes the following steps:

[0019] Given wire feed speed;

[0020] The feed nozzle tension F1, output nozzle tension F2, and delivery nozzle tension F3 are calculated using the measurements from a ring-shaped force gauge.

[0021] Calculate the tension differences F2-F1 and F3-F1;

[0022] If F2-F1 and F3-F1=0, maintain the original wire feeding speed; if F2-F1 or F3-F1>0, increase the wire feeding speed; if F2-F1 or F3-F1<0, decrease the wire feeding speed.

[0023] Furthermore, a position sensor is installed at the head of the fuselage to detect the rotation angle of the rotating chassis. The rotating chassis is controlled to rotate by the rotating motor. The rotating motor control method includes the following steps:

[0024] Scheduled welding time;

[0025] Predetermined welding speed;

[0026] The output rotation angle deviation is obtained through a fuzzy controller.

[0027] When the rotating chassis rotates to 360°, the rotating motor stops; when the rotating chassis rotates to less than 360°, the rotating motor rotates forward; when the rotating chassis rotates to more than 360°, the rotating motor rotates in reverse.

[0028] In summary, the beneficial effects of this application are as follows:

[0029] 1. A U-shaped groove is set at the head of the machine body to accommodate the pipe or bend to be welded. The rotation of the rotating chassis drives the welding torch to perform 360° all-position welding on the pipe, realizing the welding of small-diameter short straight sections of pipe or bend, saving labor.

[0030] 2. The welding torch in this application is installed by a support frame, and the support frame can keep the distance between the welding torch and the welding position stable through the action of the torsion spring and the welding pitch adjustment top wheel, thereby improving the welding quality;

[0031] 3. The wire feeding actuator and wire feeding speed control method in this application can stably feed the wire and control the wire feeding speed smoothly, thereby further improving the welding quality;

[0032] 4. This application also has the function of water cooling and shielding gas introduction at the welding position, further improving the welding quality;

[0033] 5. The welding equipment in this application has a simple structure, which is conducive to miniaturization. Its head U-shaped groove can place the pipe in the U-shaped groove for welding without disassembling the pipe, thus achieving the purpose of in-situ welding of the bent pipe. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application;

[0035] Figure 2 This is a schematic diagram of the wire feeding power mechanism in an embodiment of this application;

[0036] Figure 3 This is a schematic diagram of the wire feeding actuator in an embodiment of this application;

[0037] Figure 4 This is a schematic diagram of the head rotation power mechanism in an embodiment of this application;

[0038] Figure 5 This is a schematic diagram of the head rotation transmission mechanism in an embodiment of this application;

[0039] Figure 6 This is a schematic diagram of the head welding mechanism in an embodiment of this application;

[0040] Figure 7 This is a schematic diagram of the welding control system in an embodiment of this application;

[0041] Figure 8 This is a schematic diagram of the closed-loop control algorithm for wire feeding speed in an embodiment of this application;

[0042] Figure 9 This is a schematic diagram of the wire feeding system in an embodiment of this application;

[0043] Figure 10 This is a schematic diagram of the head rotation fuzzy control algorithm in the embodiments of this application;

[0044] Figure 11 This is a schematic diagram of the head rotation blurring controller in the embodiments of this application;

[0045] Figure 12 This is a schematic diagram of the membership function in the embodiments of this application;

[0046] Figure 13This is a schematic diagram of fuzzy rules in an embodiment of this application;

[0047] Figure 14 This is a schematic diagram of the main interface of the all-position welding software in this embodiment of the application;

[0048] Figure 15 This is a schematic diagram of the welding parameter setting interface of the all-position welding software in the embodiments of this application;

[0049] Figure 16 This is a schematic diagram of the four-segment welding speed and time setting interface of the all-position welding software in this application embodiment.

[0050] In the diagram, 1. Wire spool; 2. Wire feeding actuator; 3. Pipe clamping mechanism; 4. Wire feeding power mechanism; 5. Head rotation power mechanism; 6. Water, electricity, and gas input mechanism; 7. Housing; 8. Head welding mechanism; 9. Head rotation transmission mechanism; 10. Wire hose; 11. Machine body; 12. Pipe to be welded; 21. Wire feeding motor mounting base; 22. Wire feeding bevel gear; 23. Wire feeding motor; 24. Wire outlet nozzle; 25. Fixing pin; 26. Bevel gear shaft; 27. Revolving door mounting shaft; 28. Revolving door; 29. ​​Driven spur gear shaft; 30. Wire feeding actuator support base; 31. Wire inlet nozzle; 32. Driven spur gear; 33. Driven spur gear; 34. Revolving door shaft; 35. Top cover; 36. Bearing; 49. Rotary... 50. Rotary motor; 51. Rotary drive bevel gear; 52. Rotary driven bevel gear; 53. Rotary driven spur gear; 54. Rotary motor mounting base; 56. Transmission spur gear; 57. Planetary spur gear; 58. Upper mounting plate of crescent gear; 59. Upper limit plate; 60. Rotary chassis; 61. Lower limit plate; 62. Crescent gear base; 63. Crescent spur gear; 64. Torsion spring; 65. Support frame rotating shaft; 66. Welding mechanism base; 67. Support frame; 68. Welding pitch adjustment top wheel; 69. Welding torch mounting base; 70. Head water cooling input end; 71. Head welding negative input end; 72. Head protective gas input end; 73. Welding torch; 74. Thread feed nozzle fixing block; 75. Thread feed nozzle. Detailed Implementation

[0051] The specific embodiments of this application are described in detail below with reference to the accompanying drawings. Example 1

[0052] refer to Figure 1-6 A small-diameter short straight section bend pipe all-position welding equipment includes a machine body. The head of the machine body has a U-shaped groove for placing the workpiece to be welded. The welding equipment in this application is mainly used for welding small-diameter short straight section pipes or bend pipes. Therefore, the "pipe", "bend pipe" and "workpiece" mentioned in this embodiment should all be understood as the workpiece of the welding equipment.

[0053] The head of the fuselage is provided with a rotating chassis, and the fuselage is provided with a head rotation transmission mechanism and a head rotation power mechanism for driving the rotating chassis to rotate on the fuselage.

[0054] like Figure 1 and 5 As shown, the head rotation transmission mechanism includes a crescent-shaped toothed gear base, a crescent-shaped spur gear, a transmission spur gear, a crescent-shaped toothed gear upper fixing plate, a lower limit plate, and an upper limit plate. The crescent-shaped toothed gear base is installed on the head of the machine body, and the lower limit plate and the upper limit plate are fixed to the machine body. The crescent-shaped spur gear is disposed inside the crescent-shaped toothed gear base, and the crescent-shaped toothed gear upper fixing plate is fixed on the crescent-shaped spur gear. The rotating chassis is installed on the crescent-shaped toothed gear upper fixing plate and is located above the upper limit plate. The transmission spur gear is connected to the crescent-shaped spur gear through a planetary spur gear.

[0055] The crescent-shaped spur gear is mounted on a crescent-shaped gear base and is confined by the base, allowing it to rotate. Multiple planetary spur gears are installed at equal angular intervals on the side of the crescent-shaped spur gear and mesh with it. These planetary spur gears further radially confine the crescent-shaped spur gear, resulting in smoother rotation. A transmission spur gear meshes with one of the planetary spur gears.

[0056] The upper fixed plate, lower limit plate, and upper limit plate of the crescent-shaped gear all have grooves adapted to the shape of the U-shaped groove. The upper fixed plate of the crescent-shaped gear is fixedly connected to the crescent-shaped spur gear. The lower limit plate is fixed to the machine body and located above the upper fixed plate of the crescent-shaped gear, used to limit the vertical position of the crescent-shaped spur gear and the upper fixed plate of the crescent-shaped gear. The upper limit plate is installed above the lower limit plate and fixed to the lower limit plate. The rotating chassis is located above the upper limit plate and fixed to the upper fixed plate of the crescent-shaped gear, and can rotate synchronously with the crescent-shaped spur gear. The upper limit plate has a groove for accommodating the rotating chassis and limiting the rotation of the rotating chassis.

[0057] like Figure 1 and 4 As shown, the head rotation power mechanism includes a rotary motor, a rotary driving bevel gear, a rotary driven bevel gear, a rotary shaft, a rotary driven spur gear, and a rotary motor mounting base. The rotary motor mounting base is mounted on the machine body. The rotary motor sequentially drives the transmission spur gear to rotate via the rotary driving bevel gear, the rotary driven bevel gear, the rotary shaft, and the rotary driven spur gear, thereby driving the rotating chassis to rotate. The rotary driven bevel gear, the rotary shaft, and the rotary driven spur gear are all mounted on the rotary motor mounting base, and the rotary driven spur gear meshes with the transmission spur gear in the head rotation transmission mechanism.

[0058] like Figure 1 and 6As shown, a head welding mechanism is provided on the rotating chassis. The head welding mechanism includes a welding torch, a welding mechanism base, a support frame, a welding torch fixing seat, and a wire feed nozzle fixing block, all mounted on the rotating chassis. The welding mechanism base is mounted on the rotating chassis. The support frame is rotatably mounted on the welding mechanism base via a support frame rotation shaft. A torsion spring is provided on the support frame rotation shaft, and a welding pitch adjustment top wheel is provided on the support frame. The welding torch fixing seat and the wire feed nozzle fixing block are mounted on the support frame, the welding torch is mounted on the welding torch fixing seat, and a wire feed nozzle is provided on the wire feed nozzle fixing block. The torsion spring applies a torsional force to the support frame, causing the support frame to move towards the workpiece, thereby bringing the welding pitch adjustment top wheel into contact with the workpiece. When the rotating chassis rotates, the contact between the welding pitch adjustment top wheel and the workpiece ensures a stable distance between the workpiece and the welding torch, maintaining a constant arc pressure. This is suitable for welding pipes of different diameters.

[0059] In this embodiment, the diameter of the groove on the rotating chassis is 30mm, which can support the rotational welding of pipes with a diameter of 10-30mm.

[0060] like Figure 1 As shown, the machine body is also equipped with a pipe clamping mechanism, which is located below the head of the machine body and is used to fix the pipe to be welded. In this embodiment, the pipe clamping mechanism includes a clamping base, two opposing grippers, and a V-shaped positioning seat. The grippers are connected to the clamping base by screws, and the pipe is clamped by the two grippers and the V-shaped positioning seat. In some other embodiments, the pipe clamping mechanism may also be a controllable pneumatic clamp.

[0061] The support frame is also equipped with a head water-cooling input terminal, a head welding negative electrode input terminal, and a head protective gas input terminal. The machine body is equipped with a water, electricity, and gas input mechanism for connecting to external water, electricity, and gas, which are respectively connected to the head water-cooling input terminal, the head welding negative electrode input terminal, and the head protective gas input terminal via water pipes, wires, and gas pipes. This provides water-cooling circulation for welding head cooling, creates a stable protective atmosphere, and improves welding quality.

[0062] like Figure 1 and 3 As shown, the machine body is also equipped with a wire spool, a wire feeding actuator, and a wire feeding power mechanism.

[0063] The welding wire spool is detachably mounted on the machine body and can rotate on the machine body. Welding wire is wound on the welding wire spool.

[0064] The wire feeding actuator includes a wire feeding actuator support mounted on the machine body. The support has a wire inlet, a wire outlet, a drive spur gear, and a rotating door. The rotating door is rotatably mounted on the support and is connected to a rotating door fixing shaft. The rotating door fixing shaft passes through the rotating door and the support to fix the rotating door to the support. The support has a fixing pin that passes through the rotating door fixing shaft for securing it. A driven spur gear is located inside the rotating door. Both the drive and driven spur gears have U-shaped wire grooves for the wire to pass through. The drive spur gear is connected to an input bevel gear via a bevel gear shaft. The bevel gear shaft, input bevel gear, and drive spur gear are all housed within the support. The bevel gear shaft has a bearing to reduce rotational friction, and the support has an end cap to cover one end of the bevel gear shaft. The rotating door is rotatably mounted on the wire feeding actuator support via a rotating door shaft on one side. By opening and closing the rotating door, the distance between the driving spur gear and the driven spur gear can be controlled, thereby controlling the engagement and disengagement relationship between the driving and driven spur gears. When the driving and driven spur gears mesh, their relative rotation achieves the feeding of the welding wire.

[0065] like Figure 1 and 2 As shown, the wire feeding power mechanism includes a wire feeding motor mounting base, a wire feeding motor, and a wire feeding bevel gear. The wire feeding motor mounting base is mounted on the machine body, and the wire feeding motor is mounted on the wire feeding motor mounting base. The wire feeding bevel gear meshes with an input bevel gear. The wire feeding motor drives the input bevel gear to rotate through the wire feeding bevel gear.

[0066] It also includes a welding wire hose, one end of which is connected to the wire outlet nozzle and the other end of which is connected to the wire feed nozzle.

[0067] The device has an outer shell that covers parts of the device. It is understandable that, depending on the needs of the area to be covered or obscured, there can be more than one outer shell. The specific location of the outer shell is set according to the specific requirements.

[0068] It also includes welding control systems, such as Figure 7 As shown, the welding control system includes a human-machine interface touch screen and a central controller. The human-machine interface touch screen and the central controller are communicatively connected. The central controller is used to control a rotary motor, a wire feeding motor, a protective gas solenoid valve installed in the gas pipeline, a water cooling control valve installed in the water pipeline, and a welding power supply for supplying power to the equipment.

[0069] like Figure 8 and 9As shown, a ring-shaped force gauge is installed at the wire inlet, wire outlet, and wire feeding nozzle respectively. The wire feeding speed is controlled by a wire feeding motor. The wire feeding speed control method includes the following steps:

[0070] Given wire feed speed;

[0071] The feed nozzle tension F1, output nozzle tension F2, and delivery nozzle tension F3 are calculated using the measurements from a ring-shaped force gauge.

[0072] Calculate the tension differences F2-F1 and F3-F1;

[0073] If F2-F1 and F3-F1=0, maintain the original wire feeding speed; if F2-F1 or F3-F1>0, increase the wire feeding speed; if F2-F1 or F3-F1<0, decrease the wire feeding speed.

[0074] like Figure 10 As shown, a position sensor is installed at the head of the machine body to detect the rotation angle of the rotating chassis. The rotating chassis is controlled to rotate by the rotating motor. The rotating motor control method includes the following steps:

[0075] Scheduled welding time;

[0076] Predetermined welding speed;

[0077] The output rotation angle deviation is obtained through a fuzzy controller.

[0078] When the rotating chassis rotates to 360°, the rotating motor stops; when the rotating chassis rotates to less than 360°, the rotating motor rotates forward; when the rotating chassis rotates to more than 360°, the rotating motor rotates in reverse.

[0079] The fuzzy control algorithm of the fuzzy controller is as follows Figure 12 As shown, a predetermined welding time and speed are set, and the rotation angle deviation is output through a fuzzy controller to determine whether the actual welding position has reached the target position. By controlling the forward and reverse rotation of the motor to approach the target position, closed-loop control between the actual welding position and the target position is achieved.

[0080] Fuzzy controller principle, such as Figure 11As shown. The standardized signal input r is divided into x and y, where x and y are the welding time and welding speed, respectively. The standardized signal output is the welding rotation angle u, and its basic universe of discourse is: x ∈ [0, 3] min, y ∈ [0, 30] cm / min, u ∈ [350, 370] °. Its corresponding fuzzy subsets are: X ∈ [S, M, L], where S: welding time is too short, M: welding time is moderate, and L: welding time is too long; Y ∈ [S, M, L], where S: welding speed is too short, M: welding speed is moderate, and L: welding speed is too high; U ∈ [VS, S, M, L, XL], where VS: welding rotation angle is too short, S: welding rotation angle is small, M: welding rotation angle is moderate, L: welding rotation angle is large, and XL: welding rotation angle is too high. The corresponding membership functions adopt triangular membership functions, such as... Figure 13 As shown in Table 1, the fuzzy rule table is as follows: If X=S and Y=S, then U=VS, the welding rotation angle is too small; if X=S and Y=M, or X=M and Y=S, then U=S, the welding rotation angle is relatively small; if X=L and Y=S, or X=M and Y=M, or X=S and Y=L, then U=M, the welding rotation angle is moderate; if X=M and Y=L, or X=L and Y=M, then U=L, the welding rotation angle is relatively large; if X=L and Y=L, then U=XL, the welding rotation angle is too large.

[0081] All-position welding software is configured on the central controller, and the software interface is displayed on a human-machine interface touchscreen. A typical all-position welding software interface design is as follows: Figure 14 As shown, in test mode, the rotation angle of the all-position welding head can be adjusted using the start and stop buttons, facilitating pipe clamping and arc initiation adjustment. In welding mode, the negative terminal of the welding power supply is connected to the welding torch, and the positive terminal is connected to the pipe to be welded. Welding can be started and stopped using the start and stop buttons. The wire feed, water cooling, and shielding gas buttons control the supply of shielding gas and welding wire, as well as the water cooling of the welding head. During welding, a water cooling malfunction may occur, leading to excessively high head temperature, or failure to supply welding wire and shielding gas, triggering a fault and illuminating the fault indicator light. The welding parameter settings interface can be accessed via the welding parameter buttons. Figure 15 As shown. Based on welding process requirements, welding voltage, welding current, wire feed speed, and shielding gas flow rate parameters are set to ensure both improved welding efficiency and welding quality. The all-position welding method divides the welding process into four stages, such as... Figure 16 As shown, the welding speed and time for each segment can be set separately, improving the adaptability of the all-position welding head for flat, overhead, and pan welding. The key is that the welding speed and time for each segment can be appropriately adjusted according to the different effects of gravity and arc force on the weld pool at different positions, thereby improving welding quality.

[0082] Through the above technical solution, the welding equipment in this application enables in-situ welding of small-diameter bends with diameters of 10-30mm and short straight sections of 50mm. It supports four-segment welding and features closed-loop wire feed speed adjustment and closed-loop control of the actual and target positions for rotary welding. This solves the problems of limited welding space for heat exchanger tubes, which precludes automatic welding, and the low efficiency and poor quality of manual welding.

[0083] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of this application, and these all fall within the protection scope of this application.

Claims

1. A small-diameter, short straight-section bend pipe all-position welding equipment, characterized in that, Includes a fuselage, the head of which has a U-shaped groove and a rotating chassis; The machine body is provided with a head rotation transmission mechanism and a head rotation power mechanism for driving the rotating chassis to rotate on the machine body. A head welding mechanism is provided on the rotating chassis, and the head welding mechanism includes a welding gun mounted on the rotating chassis; The head welding mechanism further includes a welding mechanism base, a support frame, a welding torch fixing seat, and a wire feeding nozzle fixing block. The welding mechanism base is mounted on the rotating chassis. The support frame is rotatably mounted on the welding mechanism base via a support frame rotation shaft. A torsion spring is provided on the support frame rotation shaft, and a welding pitch adjustment top wheel is provided on the support frame. The welding torch fixing seat and the wire feeding nozzle fixing block are mounted on the support frame. The welding torch is mounted on the welding torch fixing seat, and a wire feeding nozzle is provided on the wire feeding nozzle fixing block. The torsion spring applies a torsional force to the support frame, causing the support frame to move toward the workpiece and thus bringing the welding pitch adjustment top wheel into contact with the workpiece. When the rotating chassis rotates, the welding pitch adjustment top wheel contacts the workpiece, which can keep the distance between the workpiece and the welding torch stable and keep the arc pressure constant. It is suitable for welding pipes of different diameters.

2. The all-position welding equipment for small-diameter short straight-section bends according to claim 1, characterized in that, The head rotation transmission mechanism includes a crescent-shaped toothed gear base, a crescent-shaped spur gear, a transmission spur gear, a crescent-shaped toothed gear upper fixing plate, a lower limit plate, and an upper limit plate. The crescent-shaped toothed gear base is installed on the head of the machine body, and the lower limit plate and the upper limit plate are fixed to the machine body. The crescent-shaped spur gear is disposed inside the crescent-shaped toothed gear base, and the crescent-shaped toothed gear upper fixing plate is fixed on the crescent-shaped spur gear. The rotating chassis is installed on the crescent-shaped toothed gear upper fixing plate and is located above the upper limit plate. The transmission spur gear is connected to the crescent-shaped spur gear through a planetary spur gear.

3. The all-position welding equipment for small-diameter short straight section bends according to claim 1, characterized in that, The head rotation power mechanism includes a rotary motor, a rotary driving bevel gear, a rotary driven bevel gear, a rotary shaft, a rotary driven spur gear, and a rotary motor mounting base. The rotary motor mounting base is mounted on the machine body. The rotary motor drives the transmission spur gear to rotate sequentially through the rotary driving bevel gear, the rotary driven bevel gear, the rotary shaft, and the rotary driven spur gear, thereby driving the rotary chassis to rotate.

4. The all-position welding equipment for small-diameter short straight section bends according to claim 3, characterized in that, A position sensor is installed at the head of the machine body to detect the rotation angle of the rotating chassis. The rotating chassis is controlled to rotate by the rotating motor. The rotating motor control method includes the following steps: Scheduled welding time; Predetermined welding speed; The output rotation angle deviation is obtained through a fuzzy controller. When the rotating chassis rotates to 360°, the rotating motor stops; when the rotating chassis rotates to less than 360°, the rotating motor rotates forward; when the rotating chassis rotates to more than 360°, the rotating motor rotates in reverse.

5. The all-position welding equipment for small-diameter short straight section bends according to claim 1, characterized in that, The support frame is also equipped with a head water cooling input terminal, a head welding negative electrode input terminal, and a head protective gas input terminal. The machine body is equipped with a water, electricity, and gas input mechanism, which is used to connect to external water, electricity, and gas, and is connected to the head water cooling input terminal, the head welding negative electrode input terminal, and the head protective gas input terminal through water pipes, wires, and gas pipes, respectively.

6. The all-position welding equipment for small-diameter short straight-section bends according to claim 1, characterized in that, The machine body is also equipped with a wire spool, a wire feeding actuator, and a wire feeding power mechanism; The welding wire spool is detachably mounted on the machine body and can rotate on the machine body, and welding wire is wound on the welding wire spool; The wire feeding actuator includes a wire feeding actuator support mounted on the machine body. The wire feeding actuator support is provided with a wire inlet, a wire outlet, a drive spur gear, and a rotating door. The rotating door is rotatably mounted on the wire feeding actuator support. A rotating door fixing shaft is connected to the rotating door. A driven spur gear is provided inside the rotating door. The drive spur gear and the driven spur gear are provided with U-shaped wire grooves for the wire to pass through. The drive spur gear is connected to an input bevel gear through a bevel gear shaft. The wire feeding power mechanism includes a wire feeding motor mounting base, a wire feeding motor, and a wire feeding bevel gear. The wire feeding motor mounting base is mounted on the machine body, and the wire feeding motor is mounted on the wire feeding motor mounting base. The wire feeding motor drives the input bevel gear to rotate through the wire feeding bevel gear. It also includes a welding wire hose, one end of which is connected to the wire outlet nozzle and the other end of which is connected to the wire feed nozzle.

7. The all-position welding equipment for small-diameter short straight-straight-section bends according to claim 6, characterized in that, A ring-shaped force gauge is installed at the wire inlet, wire outlet, and wire feeding nozzle respectively. The wire feeding speed is controlled by a wire feeding motor. The wire feeding speed control method includes the following steps: Given wire feed speed; The feed nozzle tension F1, output nozzle tension F2, and delivery nozzle tension F3 are calculated using the measurements from a ring-shaped force gauge. Calculate the tension differences F2-F1 and F3-F1; If F2-F1 and F3-F1=0, maintain the original wire feeding speed; if F2-F1 or F3-F1>0, increase the wire feeding speed; if F2-F1 or F3-F1<0, decrease the wire feeding speed.

8. The all-position welding equipment for small-diameter short straight-section bends according to claim 1, characterized in that, The machine body is also equipped with a pipe clamping mechanism, which is located below the head of the machine body and is used to fix the pipes that need to be welded.

9. The all-position welding equipment for small-diameter short straight-section bends according to claim 3, characterized in that, It also includes a welding control system, which includes a human-machine interface touch screen and a central controller. The human-machine interface touch screen and the central controller are communicatively connected. The central controller is used to control a rotary motor, a wire feeding motor, a protective gas solenoid valve installed in the gas pipeline, a water cooling control valve installed in the water pipeline, and a welding power supply for supplying power to the equipment.

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