A laser welding device for processing a heat exchanger connection pipe and a welding method thereof

Abstract

The application discloses a kind of laser welding device and welding method for heat exchanger connecting pipe processing, it is related to technical field, including welding frame, the welding frame outside is provided with welding machine, welding frame bottom is fixedly connected with mobile platform, further include: fixed plate, fixed plate is set to mobile platform mobile end, fixed plate top is provided with two mobile seats, the top of two mobile seats is fixedly connected with fixed ring, the fixed ring inside is provided with clamping mechanism, between one of fixed ring and fixed plate it is provided with screw rod for moving;The welding place of two pipe fittings is arranged in the sealed spherical shell, and the inside of it is filled with protective gas before welding, air is exhausted, oxygen is discharged during welding, reaction of metal and oxygen under high temperature is avoided to generate oxide, the purity and mechanical properties of weld metal are guaranteed.Simultaneously, after air is replaced, nitrogen, water vapor and other gases are not rolled into molten pool, significantly reduce the internal porosity defect of weld.

Description

Technical Field

[0001] This invention relates to the field of laser welding technology, and in particular to a laser welding apparatus and welding method for processing heat exchanger connecting pipes. Background Technology

[0002] In the manufacturing process of heat exchangers, laser welding between connecting pipes is a key process to ensure the product's sealing performance and mechanical properties.

[0003] Referring to patent application CN120715395B, a laser welding device for processing heat exchanger connecting pipes is disclosed, relating to the field of laser welding technology. The device includes a base body, with a front feeding conveyor belt and a rear feeding conveyor belt on the upper surface of the base body. A support frame is also provided on the upper surface of the base body, along with an auxiliary mechanism. The auxiliary mechanism includes a partition assembly and a detection assembly. The partition assembly includes a central partition plate, with side meshing plates on both sides of the central partition plate. The detection assembly includes two connecting base frames, each disposed on an inner side surface of the base body, with a detection movable plate on the upper surface of the connecting base frames.

[0004] The following problems exist during use: 1. Existing laser welding equipment mostly adopts an open or semi-open structure, making it difficult to completely replace the air at the pipe joint before welding. Residual oxygen, nitrogen, and water vapor react with the molten metal at high temperatures, easily generating oxides and forming pores, resulting in a decrease in the purity of the weld metal and making it difficult to meet the requirements for long-term reliable operation of the heat exchanger in terms of mechanical properties (such as toughness and corrosion resistance); 2. To ensure welding quality, it is usually necessary to introduce protective gas into the welding area to remove plasma and fumes. However, existing flow guiding structures are mostly fixed, and the airflow direction and angle cannot be dynamically adjusted according to pipe diameter, wall thickness, or welding parameters. The gas often blows in a divergent manner, resulting in insufficient impact force on the molten pool or deviation in direction, making it difficult to effectively remove harmful substances and guide the molten pool metal to flow in the expected direction, thus affecting the weld formation quality and penetration consistency.

[0005] Therefore, it is necessary to provide a laser welding apparatus and welding method for processing heat exchanger connecting pipes to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a laser welding apparatus and welding method for processing heat exchanger connecting pipes, so as to solve the problems of the prior art mentioned in the background art.

[0007] Based on the above ideas, the present invention provides the following technical solution: a laser welding device for processing heat exchanger connecting pipes, comprising a welding frame, a welding machine disposed on the outside of the welding frame, and a movable platform fixedly connected to the bottom of the welding frame, and further comprising:

[0008] A fixed plate is provided on the moving end of the mobile platform. Two moving seats are provided on the top of the fixed plate. A fixed ring is fixedly connected to the top of each of the two moving seats. A clamping mechanism is provided inside the fixed ring. A lead screw for movement is provided between one of the fixed rings and the fixed plate.

[0009] A sealing circular shell is disposed between two fixed rings. The top of the sealing circular shell is provided with a welding groove, and the bottom of the sealing circular shell is provided with an air inlet groove for air intake and an air outlet groove for air exhaust. The sealing circular shell is provided with a flow guiding mechanism. After the protective gas is introduced into the air inlet groove, the gas is guided to be discharged from the air outlet groove through the flow guiding mechanism.

[0010] Both sides of the sealed circular shell are fixedly connected to sealing frames, and an expansion airbag is fixedly connected to the inside of the sealing frame. The expansion airbag expands when it is ventilated and fits tightly with the pipe.

[0011] As a further aspect of the present invention: the flow guiding mechanism includes multiple rotating rods arranged in a ring around the center of the sealing shell. The multiple rotating rods all penetrate the sealing shell and are rotatably connected to the sealing shell. A guide frame is fixedly connected to the outer side of each of the multiple rotating rods. A first gear is fixedly connected to one end of each of the multiple rotating rods. A first gear ring is rotatably connected to one side of the sealing shell, and the first gear ring meshes with multiple first gears. A second gear is meshed with the outer side of the first gear ring, and the second gear is rotatably connected to the sealing shell.

[0012] As a further embodiment of the present invention: both sides of the guide frame are fixedly connected to a fixed cylinder, and a winding rod is rotatably connected inside the fixed cylinder. The winding rod is connected to the fixed cylinder by a torsion spring, and a wound air guide cloth is fixedly connected to the outside of the winding rod. A limit frame is fixedly connected to the outside of the guide frame. Two sliders are provided inside the limit frame. A connecting plate is fixedly connected between the two sliders. The connecting plate is fixedly connected to the two air guide cloths. A limit rod is fixedly connected inside the limit frame. The limit rod passes through the slider and is slidably connected to the slider. A first spring is sleeved on the outside of the limit rod, and the first spring is fixedly connected to the limit frame and the slider.

[0013] As a further aspect of the present invention: a winding reel is provided at the other end of each of the multiple rotating rods, the winding reel is rotatably connected to the sealing shell, and a third gear is fixedly connected to the outer side of each winding reel; a traction rope is fixedly connected to the outer side of each of the multiple connecting plates, the traction rope passes through the limiting frame and the rotating rod in sequence and is fixedly connected to the winding reel; a second gear ring is rotatably connected to the outer side of the sealing shell, the inner side of the second gear ring is meshed with multiple third gears, and a fourth gear is meshed with the outer side of the second gear ring, the fourth gear being rotatably connected to the sealing shell.

[0014] As a further embodiment of the present invention: a mounting base is fixedly connected to the bottom of the sealed circular shell, and two electric modules are fixedly connected to the top of the fixing plate, with the moving end of the electric module fixedly connected to the mounting base.

[0015] As a further embodiment of the present invention: the clamping mechanism includes multiple electric push rods, all of which are fixedly connected to the outside of the fixed ring, and the telescopic ends of the electric push rods pass through the fixed ring and are slidably connected to the fixed ring. The telescopic ends of the multiple electric push rods are fixedly connected to a fixed frame, and a roller is rotatably connected inside the fixed frame. A drive motor is fixedly connected to the outside of the fixed frame, and the output shaft of the drive motor is fixedly connected to the roller.

[0016] As a further aspect of the present invention: an installation cylinder is fixedly connected inside the sealing frame, and multiple installation cylinders are arranged in a ring around the center of the sealing frame. A magnetic block is slidably arranged inside the installation cylinder. A sliding rod is fixedly connected to the bottom of the magnetic block. The sliding rod passes through the bottom of the installation cylinder and is slidably connected to the installation cylinder. A contact head is fixedly connected to the bottom of the sliding rod, and a pressure sensor is arranged inside the contact head. An electromagnet is arranged inside the installation cylinder. When the electromagnet is energized, it repels the magnetic block. A conductive post is fixedly connected to the top of the electromagnet. The conductive post passes through the sealing frame and is fixedly connected to the sealing frame.

[0017] As a further embodiment of the present invention: a third gear ring is rotatably connected to the outer side of the sealing circular shell, a fifth gear is meshed with the outer side of the third gear ring, the fifth gear is rotatably connected to the sealing circular shell, a plurality of telescopic rods are fixedly connected to the inner side of the third gear ring, a conductive head is fixedly connected to one end of the plurality of telescopic rods, when the conductive head contacts the conductive post, the electromagnet is energized and generates magnetism, a third spring is fixedly connected between the conductive head and the third gear ring, and the third spring is sleeved on the outer side of the telescopic rod.

[0018] A laser welding method for processing heat exchanger connecting pipes includes the following steps:

[0019] Step 1: Clamp and position the two connecting pipes to be welded using the clamping mechanism inside the two fixing rings, and align the welding ends of the two connecting pipes together;

[0020] Step 2: Move the sealing shell to the welding point of the two pipe fittings, and then inflate the expansion bladders inside the sealing frames on both sides of the sealing shell. The expansion bladders inflate to seal the sealing shell and the pipe fittings.

[0021] Step 3: Introduce the welding protective gas into the air inlet slot and make the welding head pass through the welding slot. The protective gas circulates inside the sealed circular shell through the flow guiding mechanism and is discharged through the air outlet slot.

[0022] Step 4: Finally, the welding joint is welded using a welding machine, and the pipe fittings are rotated synchronously by a clamping mechanism to perform circumferential welding on the pipe.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. The welding joint of the two pipe fittings is located inside a sealed cylindrical shell. Before welding, a protective gas is introduced into the shell to purge the air, ensuring that oxygen is removed during the welding process. This prevents the metal from reacting with oxygen at high temperatures to form oxides, thus guaranteeing the purity and mechanical properties of the weld metal. Simultaneously, after the air is replaced, nitrogen, water vapor, and other gases are not entrained in the molten pool, significantly reducing porosity defects inside the weld.

[0025] 2. The connecting plate pulls the air guide cloth on both sides to form a certain angle between the air guide cloth and the connecting plate. When the gas passes through the air guide cloth after the angle is formed, it will be concentrated and guided to the weld. The active control of the airflow is concentrated and blown to the weld pool, which can effectively remove the plasma, fumes and harmful gases generated during the welding process, reduce defects such as porosity and spatter, and promote the directional flow of molten metal, improve weld formation and penetration consistency.

[0026] 3. The contact head has a built-in pressure sensor that can continuously detect the pressure and changes on the pipe wall throughout the entire welding cycle. When the welding heat input causes the pipe to expand thermally or contract when it cools, the pressure fluctuation will be captured by the sensor, providing closed-loop feedback for the control system and avoiding changes in welding gap or stress concentration caused by thermal deformation.

[0027] 4. At this point, the electromagnet is de-energized, and the magnetic block retracts and resets under the action of the second spring. When the next conductive head re-contacts the conductive post, the electromagnet is energized again, causing the magnetic block to drive the sliding rod and contact head to strike the pipe. During the welding process, striking both sides of the weld with appropriate force can cause localized plastic deformation of the surface metal, thereby relaxing the internal tensile stress and converting it into compressive stress. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0030] Figure 2 This is a schematic diagram of the fixing plate structure of the present invention;

[0031] Figure 3 This is a schematic diagram of the fixing ring structure of the present invention;

[0032] Figure 4 This is a schematic diagram of the sealed circular shell structure of the present invention;

[0033] Figure 5This is a schematic cross-sectional view of the sealing circular shell structure of the present invention;

[0034] Figure 6 This is a schematic diagram of the sealing frame structure of the present invention;

[0035] Figure 7 This is a schematic diagram of the guide frame structure of the present invention;

[0036] Figure 8 This is a schematic cross-sectional view of the fixed cylinder structure of the present invention;

[0037] Figure 9 This is a schematic diagram of the third gear ring structure of the present invention;

[0038] Figure 10 This is a schematic diagram of the magnetic block structure of the present invention.

[0039] In the diagram: 1. Welding frame; 101. Moving platform; 102. Welding machine; 2. Fixed plate; 3. Moving seat; 302. Fixed ring; 303. Electric push rod; 304. Fixed frame; 305. Roller; 306. Drive motor; 307. Lead screw; 4. Sealing shell; 401. Welding groove; 402. Air inlet groove; 403. Air outlet groove; 5. Sealing frame; 501. Inflatable airbag; 6. Rotating rod; 601. Guide frame; 602. First gear; 603. First gear ring; 604. Second gear; 701. Limiting frame; 702. Fixed cylinder; 703. Slider; 704. Connecting plate; 705. Limiting rod; 706. First spring; 707. Winding rod; 708. Air guide cloth; 709. Traction rope; 710. Winding reel; 711. Third gear; 712. Second gear ring; 713. Fourth gear; 8. Mounting cylinder; 801. Magnetic block; 802. Sliding rod; 803. Contact head; 804. Second spring; 805. Conductive post; 806. Electromagnet; 901. Third gear ring; 902. Telescopic rod; 903. Conductive head; 904. Third spring; 905. Fifth gear; 10. Mounting base; 1001. Electric module. Detailed Implementation

[0040] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0041] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0042] like Figures 1 to 10As shown, a laser welding apparatus and welding method for processing heat exchanger connecting pipes include the following embodiments:

[0043] Example 1: Includes a welding frame 1, with a welding machine 102 mounted on its outer side. The welding machine 102 employs a multi-axis electric slide rail assembly, enabling it to move in the X and Y axis directions. This is existing technology and will not be further elaborated here. A moving platform 101 is fixedly connected to the bottom of the welding frame 1. Also includes:

[0044] Fixed plate 2 is set at the moving end of moving platform 101. Two moving seats 3 are set on the top of fixed plate 2. Fixed rings 302 are fixedly connected to the top of both moving seats 3. A clamping mechanism is set inside the fixed rings 302. A screw 307 for moving is set between one of the fixed rings 302 and fixed plate 2. The screw 307 passes through one of the moving seats 3 and is connected to the moving seat 3 through a ball nut pair. The screw 307 is rotatably connected to fixed plate 2.

[0045] A sealing circular shell 4 is disposed between two fixing rings 302. The top of the sealing circular shell 4 is provided with a welding groove 401, and the bottom of the sealing circular shell 4 is provided with an air inlet groove 402 for air intake and an air outlet groove 403 for air exhaust. A flow guiding mechanism is provided inside the sealing circular shell 4. After the protective gas is introduced into the air inlet groove 402, the gas is guided to be discharged from the air outlet groove 403 through the flow guiding mechanism.

[0046] Both sides of the sealing round shell 4 are fixedly connected to sealing frames 5, and an expansion airbag 501 is fixedly connected to the inside of the sealing frame 5. The expansion airbag 501 expands and fits tightly with the pipe.

[0047] In practice, the two connecting pipes to be welded are clamped and positioned by the clamping mechanisms inside the two fixing rings 302, ensuring precise alignment of the welding ends. Then, the sealing shell 4 is moved to the welding point of the two pipes. The expansion bladders 501 inside the sealing frames 5 on both sides of the sealing shell 4 are inflated, and the inflated bladders 501 fit tightly against the outer wall of the pipe, achieving a reliable seal between the sealing shell 4 and the pipe. Next, welding protective gas is introduced into the air inlet groove 402, and the welding head passes through the welding groove 401. The protective gas circulates within the sealing shell 4 through the flow guiding mechanism and is discharged through the air outlet groove 403. Finally, the welding joint is welded using welding machine 102. Simultaneously, the clamping mechanism drives the pipe fittings to rotate synchronously, achieving circumferential welding of the pipe. The welding joint of the two pipe fittings is located inside the sealed circular shell 4. Before welding, protective gas is injected into the shell to purge the air, ensuring that oxygen is removed during the welding process. This prevents the metal from reacting with oxygen at high temperatures to form oxides, thus guaranteeing the purity and mechanical properties of the weld metal. Furthermore, after the air is replaced, nitrogen, water vapor, and other gases are not entrained in the molten pool, significantly reducing porosity defects inside the weld.

[0048] Furthermore, the protective gas is circulated within the sealed circular shell 4 by the flow guiding mechanism, ensuring that the welding area is always in a uniform and stable protective atmosphere, avoiding welding defects caused by insufficient local protective gas concentration. The sealing method of the expansion bladder 501 can adapt to pipes of different diameters, improving the versatility of the device, and the sealing effect is good, effectively preventing the infiltration of outside air. The clamping mechanism drives the pipe to rotate synchronously, ensuring that the weld is uniform and consistent during the welding process, improving welding quality and efficiency.

[0049] In this embodiment, a mounting base 10 is fixedly connected to the bottom of the sealed circular shell 4, and two electric modules 1001 are fixedly connected to the top of the fixing plate 2. The moving end of the electric module 1001 is fixedly connected to the mounting base 10.

[0050] The clamping mechanism includes multiple electric push rods 303, all of which are fixedly connected to the outside of the fixed ring 302. The telescopic ends of the electric push rods 303 pass through the fixed ring 302 and are slidably connected to the fixed ring 302. The telescopic ends of the multiple electric push rods 303 are fixedly connected to a fixed frame 304. A roller 305 is rotatably connected inside the fixed frame 304. A drive motor 306 is fixedly connected to the outside of the fixed frame 304. The output shaft of the drive motor 306 is fixedly connected to the roller 305.

[0051] In practice, by activating the electric push rod 303, the electric push rod 303 drives the rollers 305 inside the fixed frame 304 to make close contact with the outside of the pipe fitting. Multiple rollers 305 work together to clamp the pipe fitting in the center, ensuring that the two pipe fittings are precisely aligned and avoiding axial offset or misalignment during welding, thus ensuring the uniformity and consistency of the weld. In addition, the drive motor 306 on the outside of the fixed frame 304 drives the rollers 305 to rotate. The friction between the rollers 305 and the pipe fitting causes the pipe fitting to rotate synchronously, enabling the welding machine 102 to perform continuous and stable circumferential welding, effectively improving welding efficiency and quality.

[0052] Meanwhile, the output shaft of the external motor drives the lead screw 307 to rotate, and the rotation of the lead screw 307 causes one of the movable seats 3 to slide along the fixed plate 2, thereby flexibly adjusting the distance between the two clamping mechanisms to adapt to the welding requirements of pipe fittings of different lengths, and improving the versatility and ease of operation of the device.

[0053] Example 2: The flow guiding mechanism includes multiple rotating rods 6 arranged in a ring around the center of the sealing shell 4. The multiple rotating rods 6 all pass through the sealing shell 4 and are rotatably connected to the sealing shell 4. A guide frame 601 is fixedly connected to the outside of each of the multiple rotating rods 6. A first gear 602 is fixedly connected to one end of each of the multiple rotating rods 6. A first gear ring 603 is rotatably connected to one side of the sealing shell 4, and the first gear ring 603 is meshed with the multiple first gears 602. A second gear 604 is meshed with the outside of the first gear ring 603, and the second gear 604 is rotatably connected to the sealing shell 4.

[0054] In practice, when the protective gas is injected into the sealed circular shell 4 through the air inlet groove 402, multiple inclined guide frames 601 guide the gas, causing the protective gas to flow rapidly in a predetermined direction, forming an orderly airflow field, thereby efficiently expelling the air inside the sealed circular shell 4 and ensuring that an oxygen-free environment is quickly formed in the welding area.

[0055] Furthermore, the output shaft of an external motor is fixedly connected to a second gear 604. The second gear 604 drives the first gear ring 603, which meshes with it, to rotate. The rotation of the first gear ring 603, in turn, drives multiple first gears 602 to rotate synchronously. The first gears 602 drive the rotating rod 6 to rotate, thereby causing the guide frame 601 to deflect. By adjusting the deflection angle of the guide frame 601, the flow direction and velocity of the gas can be flexibly changed according to the size of the pipe and welding requirements, achieving precise control of the protective gas and ensuring that the best gas protection effect can be obtained when welding pipe fittings of different specifications.

[0056] Meanwhile, a negative pressure suction pipe can be installed at the venting groove 403 to promptly extract any overflowing harmful gases during welding, preventing their accumulation in the welding area. A stable oxygen-free environment effectively avoids plasma shielding issues during laser welding or arc drift problems during arc welding, resulting in more stable heat input and further improving welding quality and weld formation consistency.

[0057] In this embodiment: both sides of the guide frame 601 are fixedly connected to a fixed cylinder 702. A winding rod 707 is rotatably connected inside the fixed cylinder 702. The winding rod 707 is connected to the fixed cylinder 702 by a torsion spring. A wound air guide cloth 708 is fixedly connected to the outside of the winding rod 707. A limit frame 701 is fixedly connected to the outside of the guide frame 601. Two sliders 703 are provided inside the limit frame 701. A connecting plate 704 is fixedly connected between the two sliders 703. The connecting plate 704 is fixedly connected to the two air guide cloths 708. A limit rod 705 is fixedly connected inside the limit frame 701. The limit rod 705 passes through the slider 703 and is slidably connected to the slider 703. A first spring 706 is sleeved on the outside of the limit rod 705. The first spring 706 is fixedly connected to the limit frame 701 and the slider 703.

[0058] Each of the multiple rotating rods 6 has a take-up reel 710 at its other end. The take-up reel 710 is rotatably connected to the sealing shell 4, and a third gear 711 is fixedly connected to the outer side of each take-up reel 710. A traction rope 709 is fixedly connected to the outer side of each of the multiple connecting plates 704. The traction rope 709 passes through the limit frame 701 and the rotating rod 6 in sequence and is fixedly connected to the take-up reel 710. A second gear ring 712 is rotatably connected to the outer side of the sealing shell 4. The inner side of the second gear ring 712 is meshed with multiple third gears 711, and a fourth gear 713 is meshed with the outer side of the second gear ring 712. The fourth gear 713 is rotatably connected to the sealing shell 4.

[0059] In practice, when the gas flows inside the sealed cylindrical shell 4, it flows along the guiding direction of the guide frame 601. However, the blowing angle of the gas at the welding point cannot be adjusted. Therefore, this solution provides fixed cylinders 702 on both sides of the guide frame 601 and uses the air guide cloth 708 to block the gas. When it is necessary to adjust the blowing angle of the gas at the molten pool, a motor can be installed on the outside of the sealed cylindrical shell 4. The output shaft of the motor drives the fourth gear 713 to rotate. The fourth gear 713 drives the second gear ring 712 that meshes with it to rotate. The second gear ring 712 drives multiple meshing third gears 711 to rotate. The third gears 711 drive the winding reel 710 to rotate. The winding reel 710 winds up the traction rope 709, and then the traction rope 709 pulls the connecting plate 704, causing the connecting plate 704 to move inside the limiting frame 701. At this time, the connecting plate 704 pulls the air guide cloths 708 on both sides, so that the air guide cloths 708 and the connecting plate 704 form a certain angle. When the gas passes through the air guide cloths 708 after the angle is formed, it will be concentrated and guided to the weld. The airflow is actively controlled and concentrated to the weld pool, which can effectively remove the plasma, fumes and harmful gases generated during the welding process, reduce defects such as porosity and spatter, and promote the directional flow of molten metal, improve weld formation and penetration consistency.

[0060] Example 3: An installation cylinder 8 is fixedly connected inside the sealing frame 5. Multiple installation cylinders 8 are arranged in a ring around the center of the sealing frame 5. A magnetic block 801 is slidably arranged inside the installation cylinder 8. A sliding rod 802 is fixedly connected to the bottom of the magnetic block 801. The sliding rod 802 passes through the bottom of the installation cylinder 8 and is slidably connected to the installation cylinder 8. A contact head 803 is fixedly connected to the bottom of the sliding rod 802. A pressure sensor is installed inside the contact head 803. An electromagnet 806 is installed inside the installation cylinder 8. When the electromagnet 806 is energized, it repels the magnetic block 801. A conductive post 805 is fixedly connected to the top of the electromagnet 806. The conductive post 805 passes through the sealing frame 5 and is fixedly connected to the sealing frame 5.

[0061] In practice, once the expansion air bladder 501 inside the sealing frame 5 is tightly fitted with the connecting pipe, the multiple mounting cylinders 8 inside the sealing frame 5 begin to operate. When the electromagnet 806 is energized and generates magnetism, it pushes the magnetic block 801 to move through magnetic repulsion, causing the magnetic block 801 to drive the contact head 803 at the bottom of the sliding rod 802 to contact the outside of the connecting pipe. This magnetic force helps the pipe maintain coaxiality and reduces misalignment. Simultaneously, the contact head 803 has a built-in pressure sensor that can continuously detect the pressure and changes on the pipe wall throughout the entire welding cycle. When welding heat input causes the pipe to expand thermally or contract upon cooling, pressure fluctuations are captured by the sensor, providing closed-loop feedback to the control system, such as adjusting clamping force or welding parameters, to avoid changes in welding gap or stress concentration caused by thermal deformation.

[0062] In this embodiment, a third gear ring 901 is rotatably connected to the outer side of the sealing shell 4, and a fifth gear 905 is meshed with the outer side of the third gear ring 901. The fifth gear 905 is rotatably connected to the sealing shell 4. Multiple telescopic rods 902 are fixedly connected to the inner side of the third gear ring 901. A conductive head 903 is fixedly connected to one end of each telescopic rod 902. The conductive head 903 is electrically connected to an external power source. When the conductive head 903 contacts the conductive post 805, the electromagnet 806 is energized and generates magnetism. A third spring 904 is fixedly connected between the conductive head 903 and the third gear ring 901. The third spring 904 is sleeved on the outer side of the telescopic rod 902.

[0063] In practical implementation, after welding is completed, this scheme can also use an external motor to drive the fifth gear 905 to rotate, which in turn drives the third gear ring 901 to rotate, causing the conductive head 903 on the third gear ring 901 to be misaligned with the conductive post 805. At this time, the electromagnet 806 is de-energized, and the magnetic block 801 retracts and resets under the action of the second spring 804. When the next conductive head 903 re-contacts the conductive post 805, the electromagnet 806 is energized again, causing the magnetic block 801 to drive the sliding rod 802 and the contact head 803 to strike the pipe. During the welding process, striking both sides of the weld with appropriate force can cause local plastic deformation of the surface metal, thereby relaxing the internal tensile stress and converting it into compressive stress. Appropriate striking can cause the weld metal to vibrate slightly, which helps to expel residual gas in the molten pool and reduce internal defects such as porosity and shrinkage. At the same time, the compressive stress generated by striking can inhibit the generation of welding hot cracks.

[0064] A laser welding method for processing heat exchanger connecting pipes includes the following steps:

[0065] Step 1: Clamp and position the two connecting pipes to be welded using the clamping mechanisms inside the two fixing rings 302, and align the welding ends of the two connecting pipes together.

[0066] Step 2: Move the sealing shell 4 to the welding point of the two pipe fittings, and then inflate the expansion airbags 501 inside the sealing frames 5 on both sides of the sealing shell 4. The expansion airbags 501 inflate to seal the sealing shell 4 and the pipe fittings.

[0067] Step 3: Introduce the welding protective gas into the air inlet slot 402 and make the welding head pass through the welding slot 401. The protective gas circulates inside the sealed circular shell 4 through the flow guiding mechanism inside the sealed circular shell 4 and is discharged through the air outlet slot 403.

[0068] Step 4: Finally, the welding joint is welded using welding machine 102, and the pipe is rotated synchronously by the clamping mechanism to perform circumferential welding on the pipe.

[0069] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0070] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0071] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A laser welding apparatus for processing heat exchanger connecting pipes, comprising a welding frame (1), wherein a welding machine (102) is disposed on the outer side of the welding frame (1), and a movable platform (101) is fixedly connected to the bottom of the welding frame (1), characterized in that, Also includes: A fixed plate (2) is set on the moving end of the moving platform (101). Two moving seats (3) are set on the top of the fixed plate (2). A fixed ring (302) is fixedly connected to the top of each of the two moving seats (3). A clamping mechanism is set inside the fixed ring (302). A screw rod (307) for moving is set between one of the fixed rings (302) and the fixed plate (2). A sealing circular shell (4) is disposed between two fixing rings (302). The top of the sealing circular shell (4) is provided with a welding groove (401), and the bottom of the sealing circular shell (4) is provided with an air inlet groove (402) for air intake and an air outlet groove (403) for air exhaust. The sealing circular shell (4) is provided with a flow guiding mechanism inside. After the protective gas is introduced into the air inlet groove (402), the gas is guided to be discharged from the air outlet groove (403) through the flow guiding mechanism. Both sides of the sealed circular shell (4) are fixedly connected to a sealing frame (5), and an expansion airbag (501) is fixedly connected to the inside of the sealing frame (5). The expansion airbag (501) expands and fits tightly with the pipe.

2. The laser welding apparatus for processing heat exchanger connecting pipes according to claim 1, characterized in that: The flow guiding mechanism includes multiple rotating rods (6) arranged in a ring around the center of the sealing shell (4). The multiple rotating rods (6) all pass through the sealing shell (4) and are rotatably connected to the sealing shell (4). A guide frame (601) is fixedly connected to the outside of the multiple rotating rods (6). A first gear (602) is fixedly connected to one end of the multiple rotating rods (6). A first gear ring (603) is rotatably connected to one side of the sealing shell (4), and the first gear ring (603) meshes with the multiple first gears (602). A second gear (604) is meshed with the outside of the first gear ring (603), and the second gear (604) is rotatably connected to the sealing shell (4).

3. The laser welding apparatus for processing heat exchanger connecting pipes according to claim 2, characterized in that: The guide frame (601) is fixedly connected to two sides by fixed cylinders (702). A winding rod (707) is rotatably connected inside the fixed cylinder (702). The winding rod (707) and the fixed cylinder (702) are connected by a torsion spring. A wind-guiding cloth (708) is fixedly connected to the outside of the winding rod (707). A limit frame (701) is fixedly connected to the outside of the guide frame (601). Two sliders (703) are provided inside the limit frame (701). A connecting plate (704) is fixedly connected between (703), and the connecting plate (704) is fixedly connected to two air guide cloths (708). A limiting rod (705) is fixedly connected inside the limiting frame (701). The limiting rod (705) passes through the slider (703) and is slidably connected to the slider (703). A first spring (706) is sleeved on the outside of the limiting rod (705), and the first spring (706) is fixedly connected to the limiting frame (701) and the slider (703).

4. The laser welding apparatus for processing heat exchanger connecting pipes according to claim 3, characterized in that: Multiple rotating rods (6) are equipped with a winding reel (710) at the other end. The winding reel (710) is rotatably connected to the sealing shell (4). A third gear (711) is fixedly connected to the outside of the winding reel (710). A traction rope (709) is fixedly connected to the outside of multiple connecting plates (704). The traction rope (709) passes through the limit frame (701) and the rotating rod (6) in sequence and is fixedly connected to the winding reel (710). A second gear ring (712) is rotatably connected to the outside of the sealing shell (4). The inside of the second gear ring (712) is meshed with multiple third gears (711). A fourth gear (713) is meshed with the outside of the second gear ring (712). The fourth gear (713) is rotatably connected to the sealing shell (4).

5. The laser welding apparatus for processing heat exchanger connecting pipes according to claim 2, characterized in that: The bottom of the sealed circular shell (4) is fixedly connected to the mounting base (10), and the top of the fixing plate (2) is fixedly connected to two electric modules (1001). The moving end of the electric module (1001) is fixedly connected to the mounting base (10).

6. The laser welding apparatus for processing heat exchanger connecting pipes according to claim 5, characterized in that: The clamping mechanism includes multiple electric push rods (303), all of which are fixedly connected to the outside of the fixed ring (302). The telescopic ends of the electric push rods (303) pass through the fixed ring (302) and are slidably connected to the fixed ring (302). The telescopic ends of the multiple electric push rods (303) are fixedly connected to a fixed frame (304). A roller (305) is rotatably connected inside the fixed frame (304). A drive motor (306) is fixedly connected to the outside of the fixed frame (304). The output shaft of the drive motor (306) is fixedly connected to the roller (305).

7. The laser welding apparatus for processing heat exchanger connecting pipes according to claim 6, characterized in that: An installation cylinder (8) is fixedly connected inside the sealing frame (5). Multiple installation cylinders (8) are arranged in a ring around the center of the sealing frame (5). A magnetic block (801) is slidably arranged inside the installation cylinder (8). A sliding rod (802) is fixedly connected to the bottom of the magnetic block (801). The sliding rod (802) passes through the bottom of the installation cylinder (8) and is slidably connected to the installation cylinder (8). A contact head (803) is fixedly connected to the bottom of the sliding rod (802). A pressure sensor is installed inside the contact head (803). An electromagnet (806) is installed inside the installation cylinder (8). When the electromagnet (806) is energized, it repels the magnetic repulsion of the magnetic block (801). A conductive post (805) is fixedly connected to the top of the electromagnet (806). The conductive post (805) passes through the sealing frame (5) and is fixedly connected to the sealing frame (5).

8. The laser welding apparatus for processing heat exchanger connecting pipes according to claim 7, characterized in that: The outer side of the sealed circular shell (4) is rotatably connected to a third gear ring (901), and the outer side of the third gear ring (901) is meshed with a fifth gear (905). The fifth gear (905) is rotatably connected to the sealed circular shell (4). The inner side of the third gear ring (901) is fixedly connected to multiple telescopic rods (902). One end of the multiple telescopic rods (902) is fixedly connected to a conductive head (903). When the conductive head (903) contacts the conductive post (805), the electromagnet (806) is energized and generates magnetism. The conductive head (903) is fixedly connected to the third gear ring (901), and the third spring (904) is sleeved on the outer side of the telescopic rod (902).

9. A laser welding method for processing heat exchanger connecting pipes, employing a laser welding apparatus for processing heat exchanger connecting pipes as described in any one of claims 1 to 8, characterized in that: Includes the following steps: Step 1: Clamp and position the two connecting pipes to be welded using the clamping mechanism inside the two fixing rings (302), and make the welding ends of the two connecting pipes butt together; Step 2: Move the sealing shell (4) to the welding point of the two pipe fittings by moving the sealing shell (4). Then inflate the expansion airbags (501) inside the sealing frames (5) on both sides of the sealing shell (4). The expansion airbags (501) inflate to seal the sealing shell (4) and the pipe fittings. Step 3: Then introduce the welding protective gas into the air inlet groove (402) and make the welding head pass through the welding groove (401). The protective gas circulates inside the sealed circular shell (4) through the flow guiding mechanism inside the sealed circular shell (4) and is discharged through the air outlet groove (403). Step 4: Finally, the welding joint is welded using a welding machine (102), and the pipe is rotated synchronously by a clamping mechanism to perform circumferential welding on the pipe.

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