Automatic welding workstation and welding method for elliptical pipe

Abstract

The present invention relates to the technical field of air cooler production, and specifically to an automatic welding workstation and welding method for elliptical pipes, wherein the automatic welding workstation includes two positioners, each positioner is provided with an elliptical pipe to be welded, and the elliptical pipe is defined to extend in the left and right directions, a welding robot is provided on the front side of the elliptical pipe, a controller is provided on the left side of the welding robot, and each positioner is provided with a positioner assembly, which includes a base, a contoured fixed gear is fixed on the base, a movable gear that rotates around its gear teeth is provided on the outer periphery of the contoured fixed gear, an end plate is fixed on the side of the movable gear close to the elliptical pipe, and a fixing device for fixing the elliptical pipe is provided on the end plate, so that the elliptical pipe rotates and moves with the movable gear, and the center of the movable gear coincides with the center of the elliptical pipe; by setting a special gear for the elliptical pipe, it is ensured that the upper surface position of the elliptical pipe remains unchanged while rotating, thereby improving the stability of welding and reducing the difficulty of robot welding programming.

Description

Technical Field

[0001] The invention relates to the technical field of air cooler production, and in particular to an automatic welding workstation and a welding method for elliptical pipes. Background Art

[0002] High-pressure air coolers are industrial heat exchange devices that use air for cooling and condensing. They are widely used in industries such as petrochemicals, coal chemical industry, steel and metallurgy, and photovoltaic power generation. Oval reducers are a key component in high-pressure air cooler production. Currently, the main welding methods for these reducers are manual welding and robotic welding.

[0003] Manual welding primarily involves manually operating the welding torch, using a positioner to hold the reducer for rotation. The torch's height is manually adjusted to accommodate the varying weld height difference (Δh) caused by the elliptical tube's rotation. As the elliptical tube rotates about its center, the weld seam directly above it will vary in height due to its major and minor axes. Therefore, the welding torch cannot remain stationary during welding, requiring the operator to constantly adjust the torch's height to accommodate the changes in weld position caused by the elliptical tube's rotation. Therefore, this method requires high welder skill, requiring constant adjustment of the torch's height and a combination of oscillations to complete the weld. However, timely torch height adjustment is often not possible during the welding process, making arc breakage common during elliptical tube welding. This can lead to quality issues such as uneven welds, undercuts, and lack of fusion.

[0004] Robotic welding primarily relies on a teach-in programming approach, which coordinates the movement of a robotic arm with a positioner, ensuring that the end of the robotic arm always maintains the correct position relative to the weld, thus achieving automatic welding. However, this method is complex to program, primarily due to the programming languages ​​used for commercially available robots, which primarily offer linear, arc, and circular motion. When an elliptical tube is rotated after being gripped by a positioner, the weld point above it undergoes a reciprocating up and down motion, and the change in Δh is not proportional to the rotation time, making programming more challenging.

[0005] For example, the Chinese patent document with authorization announcement number CN222059207U discloses a new type of elliptical pipe welding clamping device, which includes a base, a top surface of the base is provided with a slide groove, and at least one slide is slidably connected inside the slide groove, the top of the slide is fixedly installed with a clamping mechanism, and the top of the slide rod is fixedly installed with a mounting plate; wherein the clamping mechanism includes a fixing plate, a circular plate and a clamping ring, the bottom end of the fixing plate is fixedly installed on the top of the slide, the circular plate is fixedly installed on the top of the fixing plate, and the clamping ring is rotatably connected to the front side of the circular plate. The utility model pushes the clamping plate by an electric push rod, and the clamping plate can be controlled to adjust according to the size of the elliptical pipe, so as to more effectively fix the elliptical pipe, and the slide plate slides in the slide groove so that the pipe openings of the two pipes are fitted together. By pulling the handle, the slider slides in the guide groove, and then the clamping ring is rotated, thereby achieving the purpose of turning over the elliptical pipe, which can more conveniently weld the interface of the pipe.

[0006] While the aforementioned welding clamping device allows for manual flipping of the elliptical tube during manual welding, it still cannot maintain a good distance between the welding torch and the weld seam. The welding quality of the elliptical tube is significantly affected by the operator's skill, resulting in unstable welding quality. Furthermore, manual welding has low welding efficiency, which in turn reduces the production efficiency of elliptical tubes.

[0007] Therefore, in order to ensure that the weld seam of the elliptical tube always maintains the same distance from the welding gun during welding, it is necessary to design a position control device specifically for the elliptical tube to reduce the welding difficulty of the elliptical tube, ensure the welding quality of the elliptical tube, and improve the welding efficiency of the elliptical tube. Summary of the Invention

[0008] The invention provides an elliptical pipe welding tool and a manufacturing method thereof, so as to solve the technical problems of poor quality and low welding efficiency of the existing manual welding of elliptical reducer pipes.

[0009] To solve the above problems, the present invention provides an automatic welding workstation for elliptical nozzles, which adopts the following technical solutions:

[0010] An automatic welding workstation for elliptical pipes includes two positioners, each positioner is provided with an elliptical pipe to be welded, the elliptical pipe extending in the left and right directions, a welding device is provided on the front side of the two elliptical pipes, a controller is provided on the left side of the welding device, and each positioner is provided with a positioner assembly, the positioner assembly includes a base, a profiling fixed gear is fixed on the base, a movable gear is provided on the outer periphery of the profiling fixed gear and rotates around its gear teeth, an end plate is fixed on the side of the movable gear close to the elliptical pipe, and a fixing device for fixing the elliptical pipe is provided on the end plate so that the elliptical pipe rotates and moves with the movable gear, and the center of the movable gear coincides with the center of the elliptical pipe;

[0011] The movable gear drives the elliptical tube to rotate when rotating around the contoured fixed gear. At this time, the shape of the contoured fixed gear satisfies that the elliptical tube moves and rotates under the drive of the movable gear while the tangent point of its upper surface remains fixed in space.

[0012] The beneficial effect is that, when welding oval tubes, conventional methods often involve rotating the tube and manually controlling the welding torch. However, due to the varying lengths of the major and minor axes of oval tubes, the distance between the welding torch and the weld seam changes during rotation, requiring constant adjustment of the welding torch position to ensure weld quality. However, the welding torch height is often not adjusted promptly during the welding process, which can lead to arc breakage during oval tube welding, resulting in uneven welds, undercuts, and unfused welds.

[0013] By setting a contoured fixed gear of a specific shape on the positioner, the upper surface of the elliptical tube always intersects with a fixed tangent point during the rotational welding process, thereby having a fixed welding position. This avoids the problem of affecting the welding quality due to the change in the relative position of the weld seam and the welding gun during welding of the elliptical tube. Compared with manual welding methods, this method not only improves the welding quality and stability of the elliptical tube, but also improves the welding efficiency of the elliptical tube. In addition, the fixed welding gun position also reduces the programming difficulty of the welding device.

[0014] Furthermore, connecting rods extending left and right are provided between the movable gear and the end plate, and the connecting rods are fixedly connected to the corresponding movable gear and end plate respectively so that the end plate rotates and moves synchronously with the movable gear.

[0015] Furthermore, a guide groove is provided on the base and outside the profiling fixed gear, which is adapted to the outer diameter of the profiling fixed gear. An inner groove adapted to the connecting rod is also provided in the guide groove to limit the moving path of the profiling fixed gear.

[0016] The beneficial effect is that the design of the guide groove and the inner groove limits the movement path of the contoured fixed gear and the connecting rod, ensuring the accuracy of the elliptical tube during rotation and movement, thereby helping to improve the accuracy and consistency of welding.

[0017] Furthermore, a control motor is provided in the base, and an output end of the control motor is fixedly connected to the connecting rod to drive the movable gear to mesh and rotate around the contoured fixed gear.

[0018] Furthermore, the fixing device is an elliptical fixing plug, and the outer circumference of the fixing plug is fitted with the inner circumference of the elliptical tube so that the elliptical tube is inserted into the fixing plug in the left-right direction.

[0019] The beneficial effect is that the fixing plug fits the inner circumference of the oval tube, so that the oval tube can be firmly inserted into the fixing plug, which not only improves the stability of the oval tube during welding, but also facilitates the rapid replacement and positioning of the oval tube.

[0020] Furthermore, the welding device is a six-axis welding robot.

[0021] Furthermore, the two positioners are linked via a controller to control the two elliptical tubes to rotate and move synchronously.

[0022] The beneficial effect is that the linkage design of the controller realizes the synchronous rotation and movement of the two elliptical tubes, ensuring the relative position stability during the welding process, improving the accuracy and consistency of welding, and reducing the difficulty of operation.

[0023] The beneficial effects of the automatic welding workstation for elliptical pipes provided by the present invention are:

[0024] 1. Existing elliptical tube welding methods often involve rotating the tube and manually controlling the welding torch. However, due to the varying lengths of the major and minor axes of elliptical tubes, the distance between the welding torch and the weld seam changes during rotation, requiring constant adjustment of the welding torch position to ensure weld quality. However, timely adjustment of the welding torch height is often not possible during the welding process, leading to arc breakage during elliptical tube welding and resulting in uneven welds, undercuts, and unfused welds.

[0025] By setting a contoured fixed gear of a specific shape on the positioner, the upper surface of the elliptical tube always intersects with a fixed tangent point during the rotational welding process, thereby having a fixed welding position. This avoids the problem of affecting the welding quality due to the change in the relative position of the weld seam and the welding gun during welding of the elliptical tube. Compared with manual welding methods, this method not only improves the welding quality and stability of the elliptical tube, but also improves the welding efficiency of the elliptical tube. In addition, the fixed welding gun position also reduces the programming difficulty of the welding device.

[0026] 2. The fixing plug fits the inner circumference of the oval tube, so that the oval tube can be firmly inserted into the fixing plug. This not only improves the stability of the oval tube during welding, but also facilitates the rapid replacement and positioning of the oval tube.

[0027] 3. The design of the guide groove and inner groove limits the moving path of the contoured fixed gear and connecting rod, ensuring the accuracy of the elliptical tube during rotation and movement, which helps to improve the accuracy and consistency of welding.

[0028] 4. The controller's linkage design enables the synchronous rotation and movement of the two elliptical tubes, ensuring the relative position stability during the welding process. This improves welding accuracy and consistency while reducing operational difficulty.

[0029] To solve the above problems, the present invention provides a method for welding an elliptical pipe using the following technical solutions:

[0030] A welding method for an elliptical pipe, the specific steps are as follows:

[0031] a. According to the model and size of the oval tube to be welded, select the appropriate profiling fixed gear and fix the profiling fixed gear on the base of the two positioners;

[0032] b. Install the two elliptical tubes to be welded on the fixing devices of the positioner respectively, with the ends of the elliptical tubes resting on the end plates;

[0033] c. Use the controller to set the rotation and movement speed of the moving gear on the positioner so that the elliptical tube moves and rotates synchronously with the moving gear;

[0034] d. Start the welding robot through the controller, place the welding gun of the welding robot above the tangent point of the elliptical tube, start the welding gun, and weld the two elliptical tubes to be welded.

[0035] Its beneficial effect is that by setting a contoured fixed gear of a specific shape on the positioner, the upper surface of the elliptical tube always intersects with the fixed tangent point during the rotational welding process, thereby having a fixed welding position, avoiding the problem of affecting the welding quality due to the change in the relative position of the weld and the welding gun during welding of the elliptical tube. Compared with the manual welding method, it not only improves the welding quality and stability of the elliptical tube, but also improves the welding efficiency of the elliptical tube. In addition, the fixed welding gun position also reduces the programming difficulty of the welding device.

[0036] Furthermore, the fixing device is a replaceable fixing plug to adapt to oval tubes of different sizes.

[0037] Furthermore, the fixing plug has a fixed initial angle before welding, so as to improve the feeding efficiency of the elliptical tube during welding.

[0038] The advantages of this method are that the fixed initial angle of the fixed plug during welding helps improve the loading efficiency of the elliptical tube during welding, simplifies the operation process, and reduces the difficulty and cost of operation. At the same time, the fixed initial angle also helps to improve the consistency and accuracy of the welding.

[0039] The beneficial effects of the elliptical pipe welding method provided by the present invention are:

[0040] 1. By setting a contoured fixed gear of a specific shape on the positioner, the upper surface of the elliptical tube always intersects with a fixed tangent point during the rotation welding process, thereby having a fixed welding position. This avoids the problem of affecting the welding quality due to the change in the relative position of the weld and the welding gun during welding of the elliptical tube. Compared with the manual welding method, this method not only improves the welding quality and stability of the elliptical tube, but also improves the welding efficiency of the elliptical tube. In addition, the fixed welding gun position also reduces the programming difficulty of the welding device.

[0041] 2. The initial angle of the fixed plug before welding helps improve the feeding efficiency of the elliptical tube during welding, simplifies the operation process, and reduces the difficulty and cost of operation. At the same time, the fixed initial angle also helps to improve the consistency and accuracy of the welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an illustrative and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0043] Figure 1 A schematic structural diagram of an automatic welding workstation for elliptical pipes provided by the present invention;

[0044] Figure 2 It is the main view of the displacement component;

[0045] Figure 3 It is a side view of the displacement component;

[0046] Figure 4 It is a schematic diagram of the shape of the profiled fixed gear;

[0047] Figure 5 The present invention provides a schematic flow chart of a method for welding an elliptical pipe.

[0048] Description of reference numerals:

[0049] 1. Positioner; 11. Base; 12. Contour fixed gear; 13. Guide groove; 14. Inner groove; 15. Moving gear; 16. Connecting rod; 17. End plate; 18. Fixing device; 2. Oval tube; 3. Welding robot; 4. Welding wire barrel; 5. Controller; 6. Welding power supply; 7. Positioner assembly. DETAILED DESCRIPTION

[0050] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0051] The main idea of ​​the present invention is to provide a contoured fixed gear 12 of a specific shape on the positioner 1 so that the upper surface of the elliptical tube 2 always has a fixed welding position during the rotational welding process, thereby avoiding the problem of affecting the welding quality due to the change in the relative position of the weld seam and the welding gun during welding of the elliptical tube 2. Compared with the manual welding method, not only the welding quality and stability of the elliptical tube 2 are improved, but also the welding efficiency of the elliptical tube 2 is improved. In addition, the fixed welding gun position also reduces the programming difficulty of the welding robot 3.

[0052] After introducing the basic principles of the present invention, various non-limiting embodiments of the present invention are described in detail below. The numbers of any elements in the drawings are for illustration only and not for limitation, and any names are for distinction only and do not have any limiting meaning.

[0053] The principles and spirit of the present invention are explained in detail below with reference to several representative embodiments of the present invention.

[0054] Embodiment 1 of an automatic welding workstation for elliptical pipes provided by the present invention:

[0055] like Figures 1 to 4 As shown, the workstation includes two oppositely arranged positioners 1, each of which is fixed with an elliptical tube 2, which is defined as extending in the left-right direction. The two elliptical tubes 2 are respectively fixed on opposite sides of the positioner 1. A welding robot 3 is provided on the front side of the two elliptical tubes 2, and the welding robot 3 is used to weld the two elliptical tubes 2. A controller 5 is provided on the left side of the welding robot 3, and the controller 5 is used to achieve linkage and automatic control of the welding robot 3 and the positioner 1. The two positioners 1 are each provided with a positioner assembly 7, which is used to achieve relative fixation of the distance between the elliptical tube 2 and the welding gun.

[0056] The welding robot is a six-axis robot designed to accommodate the welding of elliptical tubes 2 of varying shapes and sizes, reducing welding complexity. A wire drum 4 is located between the welding robot 3 and the controller 5 to supply welding wire to the robot 3. A welding power source 6 is located below the controller 5. This digital pulse welding power source offers high control accuracy and stability.

[0057] The displacement assembly 7 includes a base 11, which contains a control motor, which is a servo motor. Two bases 11 are fixed on opposite sides with profiling fixed gears 12, which are spur gears. The specific shape of the profiling fixed gears 12 is determined by the elliptical tube 2 to be welded. The method is as follows:

[0058] like Figure 4As shown, a horizontal line and a point on the horizontal line are determined. These horizontal line and point are defined as the tangent line and tangent point of the cross-sectional ellipse of the elliptical tube 2. Under the premise that the cross-sectional ellipse is always tangent to the tangent line and the tangent point is always on the cross-sectional ellipse, the cross-sectional ellipse is rotated one circle. The motion trajectory of the center of the cross-sectional ellipse at this time is the shape of the contoured fixed gear 12. When the center of the elliptical tube 2 rotates around the contoured fixed gear 12, the upper surface of the elliptical tube 2 always intersects with the tangent point.

[0059] The derivation process of the motion trajectory of the center of the cross-sectional ellipse is as follows:

[0060] Let the horizontal line be Axis, fixed point is , the direction angle of the ellipse rotation is , the ellipse is translated while rotating to maintain: the ellipse is always Axis tangent to Point, in The tangent line at is always horizontal.

[0061] Let the semi-major axis of the ellipse be , the semi-major axis along the initial axis direction, the semi-minor axis is b, which is along the initial Axis direction. In the initial position, the center of the ellipse is , is the lower vertex of the ellipse.

[0062] The direction angle of the ellipse Represents the major axis and The angle of the axis, When changing from 0 to 360 degrees, the ellipse rotates one circle.

[0063] The coordinates of the center of the ellipse are defined as , which changes with the ellipse during its rotation changes with the changes of .

[0064] Points on the ellipse Parameterized in the local coordinate system:

[0065] , .

[0066] in is the parameter angle, after rotation, the global coordinate for:

[0067] ,

[0068] .

[0069] The ellipse always passes through , let the point correspond to the parameter ,Will and Substituting into the global coordinates we get:

[0070] ,

[0071] .

[0072] In addition, the tangent line at the tangent point is always horizontal, that is, the normal vector is parallel to , the ellipse in local coordinates The gradient at is:

[0073] ,

[0074] After rotation, the normal vector is:

[0075] ,

[0076] Normal vector parallel to ,but The axis component is 0, and we get:

[0077] ,

[0078] Then we get:

[0079]

[0080] then , .

[0081] Will and Substitution and ,get:

[0082] , .

[0083] The shape of the profiled fixed gear 12 can be derived from the above parametric equations, and when the parameters of the elliptical tube 2 change, the shape of the profiled fixed gear 12 changes accordingly according to the above parametric equations.

[0084] The outer periphery of each of the two contoured fixed gears 12 is provided with a movable gear 15 that meshes and rotates around the contoured fixed gear 12. The movable gear 15 is a circular spur gear. The base 11 has a guide groove 13 located outside the contoured fixed gear 12 and having a shape that matches the contoured fixed gear 12. The movable gear 15 is located within the guide groove 13, and the guide groove 13 restricts the movable gear 15 from rotating around the contoured fixed gear 12.

[0085] The right end of the left base 11 and the left end of the right base 11 are both equipped with end plates 17, which are vertically mounted circular plates. Connecting rods 16 are provided between the two end plates 17 and the corresponding bases 11. Connecting rods 16 are cylindrical rods extending left and right. One end of the connecting rod 16 is fixedly connected to the end plate 17, and the other end is fixedly connected to the corresponding movable gear 15. When the movable gear 15 moves and rotates around the contoured fixed gear 12 driven by the control motor, the end plate 17 also moves and rotates synchronously with the movable gear 15. The guide groove 13 also includes an inner groove 14. The end of the connecting rod 16 connected to the movable gear 15 is inserted into the inner groove 14 and fixedly connected to the control motor. The inner groove 14 is used to further define the moving trajectory of the movable gear 15, thereby improving the moving accuracy of the movable gear 15.

[0086] The right end of the left end plate 17 and the left end of the right end plate 17 are both fixed with a fixing device 18, which is used to fix the oval tube 2 to the end plate 17. The fixing device 18 is an oval fixing plug, the shape of which is adapted to the inner diameter of the oval tube 2, so that the oval tube 2 is sleeved on the fixing plug in the left and right directions, thereby improving the stability of the oval tube 2 during the welding process and facilitating the rapid replacement and positioning of the oval tube 2.

[0087] In addition, the center of the fixed plug coincides with the axis of the connecting rod 16. When the movable gear 15 rotates around the contoured fixed gear 12 driven by the control motor, the elliptical tube 2 fixed to the end plate 17 by the fixing device 18 rotates and moves synchronously with the movable gear 15. At this time, the upper surface of the elliptical tube 2 has a tangent point fixed in space to maintain a relatively fixed distance from the welding gun.

[0088] The working principle of this automatic welding workstation is as follows:

[0089] The two elliptical tubes 2 to be welded are respectively sleeved onto the fixed plugs of the two positioners 1. The welding robot 3 is then controlled by the controller 5 to move the welding gun above the joint of the two elliptical tubes 2, and the positioner 1 is started. At this time, driven by the control motor, the movable gear 15 meshes and rotates around the contoured fixed gear 12. The guide groove 13 and the inner groove 14 limit the movement path of the movable gear 15, improving the movement accuracy of the movable gear 15. Then, driven by the connecting rod 16, the two end plates 17 rotate and move synchronously with the corresponding movable gears 15, and the two elliptical tubes 2 also move synchronously. Because the two positioners 1 are linked by the controller 5, the two elliptical tubes 2 can rotate synchronously. In addition, because the contoured fixed gear 12 is customized to the size of the elliptical tube 2, the upper surface of the elliptical tube 2 always intersects at a fixed point in space when the elliptical tube 2 rotates. Then, the welding gun is started to complete the welding of the two elliptical tubes 2.

[0090] Embodiment 2 of an automatic welding workstation for elliptical pipes provided by the present invention:

[0091] The main difference between it and Example 1 is:

[0092] In Example 1, automatic welding of the elliptical tube is performed by a six-axis robot.

[0093] In this embodiment, the automatic welding of the elliptical tube is performed by a five-axis robot or other multi-axis robots.

[0094] Example 1 of a welding method for an elliptical pipe provided by the present invention:

[0095] As shown in the figure, the present invention provides an elliptical pipe welding method mainly relying on the above-mentioned automatic welding workstation for elliptical pipes to achieve the specific steps as follows:

[0096] a. Select an appropriate profiling fixed gear 12 according to the size of the oval tube 2 to be welded, and fix the profiling fixed gear 12 on the base 11 of the two positioners 1;

[0097] b. Insert the two oval tubes 2 to be welded into the fixed plugs of the positioner 1 respectively, and then press the ends of the oval tubes 2 onto the end plate 17. The fixed plugs are replaceable plugs to adapt to oval tubes 2 of different sizes; the fixed plugs have a fixed initial angle before welding, which is convenient for improving the feeding efficiency of the oval tubes 2 during welding;

[0098] c. Setting the rotation and movement speed of the moving gear 15 on the positioner 1 through the controller 5 so that the elliptical tube 2 moves and rotates synchronously with the moving gear 15;

[0099] d. Start the welding robot 3 through the controller 5, place the welding gun of the welding robot 3 above the tangent point of the elliptical tube 2, start the welding gun, and realize welding of the two elliptical tubes 2 to be welded.

[0100] Example 3 of a welding method for an elliptical pipe provided by the present invention:

[0101] The main difference between it and Example 1 is:

[0102] In Example 1, the moving gear and the baffle are synchronized in movement and rotation via a connecting rod.

[0103] In this embodiment, the movable gear is fixed on the baffle.

[0104] According to the above description of this specification, those skilled in the art may also understand that the terms used below, such as "up", "down", "front", "back", "left", "right", "width", "horizontal", "top", "bottom", "inside", "outside" and other terms indicating orientation or positional relationships are based on the orientation or positional relationships shown in the drawings of this specification. They are only for the purpose of facilitating the explanation of the scheme of the present invention and simplifying the description, rather than explicitly or implicitly indicating that the devices or elements involved must have the specific orientation, be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as limitations on the scheme of the present invention.

[0105] In addition, in the description of this specification, “a plurality of” means at least two, for example, two, three or more, etc., unless otherwise clearly and specifically defined.

Claims

1. An automatic welding workstation for elliptical pipes, comprising two positioners, each positioner being provided with an elliptical pipe to be welded, the elliptical pipes being defined to extend in a left-right direction, a welding device being provided on the front side of the two elliptical pipes, and a controller being provided on the left side of the welding device, characterized in that: Each of the positioners is provided with a position shifting assembly, which includes a base, a profiled fixed gear is fixed on the base, a movable gear is provided on the outer periphery of the profiled fixed gear and rotates around its gear teeth, an end plate is fixed on the side of the movable gear close to the elliptical tube, and a fixing device for fixing the elliptical tube is provided on the end plate so that the elliptical tube rotates and moves with the movable gear, and the center of the movable gear coincides with the center of the elliptical tube; The movable gear drives the elliptical tube to rotate when rotating around the contoured fixed gear. At this time, the shape of the contoured fixed gear satisfies that the elliptical tube moves and rotates under the drive of the movable gear while the tangent point of its upper surface remains fixed in space.

2. The automatic welding workstation for elliptical pipes according to claim 1, characterized in that: Connecting rods extending left and right are provided between the moving gear and the end plate. The connecting rods are fixedly connected to the corresponding moving gear and the end plate respectively so that the end plate rotates and moves synchronously with the moving gear.

3. The automatic welding workstation for elliptical pipes according to claim 2, characterized in that: The base is provided with a guide groove outside the profiling fixed gear, which is adapted to the outer diameter of the profiling fixed gear. The guide groove is also provided with an inner groove adapted to the connecting rod to limit the moving path of the profiling fixed gear.

4. The automatic welding workstation for elliptical pipes according to claim 3, characterized in that: A control motor is arranged in the base, and an output end of the control motor is fixedly connected to the connecting rod to drive the movable gear to engage and rotate around the contoured fixed gear.

5. The automatic welding workstation for elliptical pipes according to claim 1, characterized in that: The fixing device is an elliptical fixing plug, the outer circumference of the fixing plug is fitted with the inner circumference of the elliptical tube so that the elliptical tube is inserted into the fixing plug in the left-right direction.

6. The automatic welding workstation for elliptical pipes according to claim 1, characterized in that: The welding device is a six-axis welding robot.

7. The automatic welding workstation for elliptical pipes according to claim 1, characterized in that: The two positioners are linked via a controller to control the two elliptical tubes to rotate and move synchronously.

8. A welding method for an elliptical pipe, characterized in that: The method is implemented by using an automatic welding workstation for elliptical pipes according to any one of claims 1 to 7, and the specific steps are as follows: a. According to the model and size of the oval tube to be welded, select the appropriate profiling fixed gear and fix the profiling fixed gear on the base of the two positioners; b. Install the two elliptical tubes to be welded on the fixing devices of the positioner respectively, with the ends of the elliptical tubes resting on the end plates; c. Use the controller to set the rotation and movement speed of the moving gear on the positioner so that the elliptical tube moves and rotates synchronously with the moving gear; d. Start the welding robot through the controller, place the welding gun of the welding robot above the tangent point of the elliptical tube, start the welding gun, and weld the two elliptical tubes to be welded.

9. The method for welding an elliptical pipe according to claim 8, characterized in that: The fixing device is a replaceable fixing plug to adapt to oval tubes of different sizes.

10. The method for welding an elliptical pipe according to claim 9, characterized in that: The fixed plug has a fixed initial angle before welding, so as to improve the feeding efficiency of the elliptical tube during welding.

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