Friction stir spot welding device and method for aluminum alloy thin-wall cabin

Abstract

The invention discloses a friction stir spot welding device and method for an aluminum alloy thin-wall cabin, and relates to the technical field of welding, and the friction stir spot welding device comprises a bearing support, a roller assembly, a speed reduction driving mechanism, a wedge-shaped self-locking clamping mechanism and a spot welding tool. The roller assembly is used for fixing and adjusting the angle and position of a welding workpiece, the speed reduction driving mechanism achieves high-precision positioning through a worm gear reducer, the clamping mechanism ensures that the workpiece is stable, the wedge-shaped self-locking clamping mechanism comprises a flange plate and a tight supporting plate and is used for clamping the welding workpiece, and the spot welding tool is used for executing friction stir spot welding operation. The welding method comprises the steps of surface cleaning, workpiece clamping, welding spot accurate positioning, friction stir spot welding execution, cooling after welding, quality detection and the like. According to the welding method, for 2219-T851 aluminum alloy and 2195-T84 aluminum lithium alloy, welding parameters are optimized, and the welding quality and efficiency are improved. The method has the advantages of high welding quality, improved efficiency, reduced energy consumption, reduced rejection rate and the like, and is suitable for the manufacturing field of high-end equipment such as spaceflight and aviation.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and in particular relates to a friction stir spot welding device for an aluminum alloy thin-wall cabin. Background Art

[0002] Aluminum alloy has become the core structural material in the aerospace field due to its low density, high specific strength, excellent corrosion resistance and good machinability. With the development of advanced aerospace equipment such as reusable launch vehicles, large aluminum alloy thin-walled cabin structures are widely used due to their lightweight and high strength requirements. This type of cabin usually adopts a structural design that combines thin-walled skin and skeleton. The skin thickness is only 1 to 2 mm, and the overall diameter and height can reach several meters, requiring a large number of high-precision spot welding connections. Due to the high thermal conductivity and surface oxide film stability of aluminum alloy materials, the application of traditional welding methods in thin-walled cabin welding is greatly limited, and it is difficult to meet the aerospace manufacturing needs of high efficiency, high reliability and lightweight.

[0003] At present, the commonly used connection methods for aluminum alloy thin-walled cabins mainly include riveting, resistance spot welding and stir friction spot welding, but the former two have obvious limitations. Riveting requires drilling holes on the workpiece and using rivets, which not only increases the weight of the structure, but also weakens the integrity of the material, easily forms stress concentration, and thus reduces the fatigue life of the cabin. In addition, the riveting process is complicated and the welding efficiency is low, which makes it difficult to meet the efficient connection requirements of large-scale complex structures. Although the resistance spot welding process is mature, due to the strong thermal conductivity of aluminum alloy, the welding heat is easy to diffuse, resulting in insufficient local heating and difficult to ensure the strength of the weld. At the same time, the oxide film on the surface of the aluminum alloy has a high melting point and strong stability. It is difficult to effectively remove the oxide film by resistance spot welding, and it is easy to produce weld inclusion defects or cracks, which affects the welding quality. In addition, the adhesion problem between the electrode and the workpiece increases the maintenance cost. Therefore, these traditional methods have problems such as increased weight, unstable weld quality, and low efficiency in the welding of large-size aluminum alloy thin-walled cabins, which makes it difficult to meet the high reliability requirements of aerospace manufacturing.

[0004] Friction stir spot welding (FSSW) is an advanced solid-phase welding technology. Its principle is to generate heat through the friction of the rotating stirring needle to make the material in the welding area reach a plastic state, thereby forming a high-strength connection. Compared with traditional riveting and resistance spot welding, this technology does not require filling materials or drilling, avoids damage to the material, and achieves lightweight design. At the same time, this technology does not melt the parent material during the welding process, there are no cracks or pores inside the welded joint, and the welding strength can reach more than 90% of the parent material strength. In addition, stir friction welding has low energy consumption, avoids high-temperature oxidation and pollutant emissions caused by resistance spot welding, and meets the requirements of green manufacturing. However, the existing stir friction spot welding equipment still has problems such as weak weld quality monitoring capability, low multi-spot welding efficiency, and limited welding parameter control accuracy in the welding of large-size aluminum alloy thin-walled cabins. These limitations affect its application in high-performance aerospace manufacturing.

[0005] Therefore, there is an urgent need to develop a stir friction spot welding device and method suitable for aluminum alloy thin-walled cabin structures to solve the technical problems existing in the prior art in the manufacture of aerospace thin-walled components, such as poor welding quality consistency, low process efficiency and insufficient equipment adaptability. Summary of the invention

[0006] The purpose of the present invention is to provide an aluminum alloy thin-wall cabin body stir friction spot welding device to solve the above-mentioned technical problems existing in the prior art.

[0007] To achieve the above object, in one aspect, the present invention provides an aluminum alloy thin-wall cabin body friction stir spot welding device, comprising:

[0008] Two bearing supports arranged at intervals are used to support the main body of the device;

[0009] A roller assembly is rotatably connected between the two bearing supports, and the roller assembly includes a reducer mounting shaft, a shaft, a small flange, a positioning plate, a cone and a large flange, wherein the small end of the cone is fixed by the small flange, and the large end is fixed by the large flange;

[0010] The reduction drive mechanism includes a worm gear reducer, which is fixed to a bearing support on one side through a reducer bracket and is drivingly connected to the roller assembly for controlling the welding path;

[0011] A wedge-shaped self-locking clamping mechanism comprises a flange and a clamping plate, wherein the flange is bolted to the clamping plate and is used to clamp the welding workpiece;

[0012] Spot welding tool for performing friction stir spot welding operations.

[0013] Optionally, the roller assembly and the tightening plate are in a wedge-shaped fit.

[0014] Optionally, the cone angle of the wedge fit is 6°.

[0015] Optionally, it also includes a visual inspection system for collecting solder joint images and performing quality analysis through a computer; the visual inspection system collects solder joint images through a high-resolution industrial camera and uses a computer image processing algorithm to automatically determine the surface quality of the solder joint.

[0016] Optionally, the reduction drive mechanism further includes a handwheel connected to the input end of the worm gear reducer for manual drive adjustment.

[0017] Optionally, the flange includes a top plate, reinforcing ribs and a circular ring. The flange is connected to the tightening plate via a round nut and a bolt. The axial position of the flange is adjusted by adjusting the position of the round nut on the shaft.

[0018] In another aspect, the present invention further provides a stir friction spot welding method. According to any one of the above-mentioned aluminum alloy thin-walled cabin stir friction spot welding devices, the method comprises the following steps:

[0019] Step S1: cleaning the surface of the welding area of ​​the aluminum alloy thin-walled cabin to remove oxide film and impurities;

[0020] Step S2: clamping the cabin skin and the cabin frame by a wedge-shaped self-locking clamping mechanism;

[0021] Step S3: adjusting the position of the roller assembly through the worm gear reducer to accurately locate the welding point;

[0022] Step S4: starting the spot welding tool, setting the rotation speed to 2000-3500 rpm, the pressing amount to 1.2-2.2 mm, and the welding time to 3.0-5.0 seconds / point, and performing stir friction spot welding;

[0023] Step S5: Cool naturally after welding and keep the clamping state to prevent deformation;

[0024] Step S6: Perform quality analysis on the solder joints, and proceed to the next solder joint if they are qualified.

[0025] In some optional methods of the present invention, in step S6, a visual inspection system is used to perform quality analysis on the solder joints.

[0026] In some optional methods of the present invention, in step S4, when the welding material is 2219-T851 aluminum alloy, the rotation speed is set to 2800-2900 rpm, the pressing amount is set to 1.8-2.0 mm, and the welding time is set to 4.0-4.2 seconds / point.

[0027] In some optional methods of the present invention, in step S4, when the welding material is 2195-T84 aluminum-lithium alloy, the rotation speed is set to 2950-3050 rpm, the pressing amount is set to 1.2-1.5 mm, and the welding time is set to 3.5-3.8 seconds / point.

[0028] The present invention discloses the following technical effects:

[0029] The present invention significantly improves welding quality, production efficiency and stability by optimizing the structure of the welding device, precise positioning control and intelligent quality detection, and has the following advantages:

[0030] 1. Significantly improved welding quality

[0031] The present invention adopts a visual inspection system to automatically identify the quality of welds, reduce human misjudgment, and ensure welding consistency. The strength of the weld can reach more than 90% of the parent material, the tensile strength and mechanical properties of the welded joint are stable, and the weld structure is uniform and defect-free.

[0032] 2. Welding efficiency is greatly improved

[0033] The high-precision worm gear reduction mechanism and automatic positioning system can reduce the welding path adjustment time, improve the overall efficiency of multi-spot welding, increase the welding speed by more than 30%, and significantly improve the overall welding efficiency.

[0034] 3. Lower energy consumption

[0035] The present invention optimizes energy transmission and welding technology, reducing overall energy consumption by more than 20%, while avoiding oxidation and smoke emissions caused by high-temperature fusion welding, conforming to the green manufacturing concept and being more environmentally friendly.

[0036] 4. The scrap rate is significantly reduced

[0037] The intelligent detection system can monitor the quality of solder joints in real time, reducing the unqualified rate by more than 40%, reducing material waste and improving production economic benefits.

[0038] 5. The welding process is more stable

[0039] The wedge-shaped self-locking clamping mechanism improves welding accuracy, avoids quality problems caused by workpiece slippage during welding, ensures the stability of the welding point position, and improves the reliability and service life of the weld structure.

[0040] The invention is applicable to high-end equipment manufacturing fields such as aerospace, aviation, and automobile manufacturing, and is particularly applicable to welding of reusable rocket tanks. It can effectively improve structural strength, reduce weight, and extend service life, providing an efficient, energy-saving, and reliable welding solution for aerospace manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 It is a structural schematic diagram of the friction stir spot welding device for aluminum alloy thin-walled cabin body of the present invention;

[0043] Figure 2 It is a front view of the bearing support in the device of the present invention;

[0044] Figure 3 A side view of a bearing support in the device of the present invention;

[0045] Figure 4 It is a front view of the reducer bracket in the device of the present invention;

[0046] Figure 5 It is a side view of the reducer bracket in the device of the present invention;

[0047] Figure 6 It is a front view of the flange in the device of the present invention;

[0048] Figure 7 It is a side view of the flange in the device of the present invention;

[0049] Figure 8 A front view of a drum assembly in the device of the present invention;

[0050] Fig. 9 It is a side view of the roller assembly in the device of the present invention.

[0051] Among them, 1. bearing support; 2. bolt one; 5. reducer bracket; 6. worm gear reducer; 8. handwheel; 9. seat bearing; 10. round nut; 11. flange; 12. bolt two; 13. tightening plate; 14. roller assembly; 15. cabin skin; 16. cabin frame; 17. spot welding tool; 18. visual inspection system; 19. computer; 20. bracket mounting plate; 21. bearing mounting plate; 22. horizontal brace; 23. vertical brace; 24. bottom plate; 25. reducer mounting plate; 26. reinforcement plate; 27. side plate; 28. top plate; 29. ​​reinforcement rib; 30. ring; 31. reducer mounting shaft; 32. shaft; 33. small flange; 34. positioning plate; 35. cone; 36. large flange. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] The embodiment of the present invention discloses a stir friction spot welding device and method for aluminum alloy thin-wall cabin, which aims to solve the problems of unstable welding quality, low efficiency and insufficient equipment adaptability in the manufacture of aerospace thin-wall components in the existing welding technology. In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0054] Embodiment 1

[0055] Reference Figures 1 to 9 As shown, the first embodiment of the present invention provides an aluminum alloy thin-wall cabin friction stir spot welding device, including a spot welding tool 17, a visual inspection system 18, a roller assembly 14, a wedge-shaped self-locking clamping mechanism, a speed reduction drive mechanism and a bearing support 1. Figure 1 As shown, two bearing supports 1 are arranged at intervals to support the entire spot welding device; the roller assembly 14 is rotatably connected to the two bearing supports 1, and one end of the roller assembly 14 is connected to the reduction drive mechanism to support and fix the welding workpiece (aluminum alloy thin-walled cabin body) and to adjust the angle and position of the welding point; the reduction drive mechanism is fixed to the bearing support 1 on one side through the reducer bracket 5, which is used to accurately adjust the welding path and ensure high-precision positioning of the welding point position; the wedge-shaped self-locking clamping mechanism includes a flange 11 and a clamping plate 13, which are used to firmly clamp the aluminum alloy thin-walled cabin body to prevent displacement or deformation during welding; the spot welding tool 17 is used to perform stir friction spot welding operations to form a high-strength connection between the aluminum alloy skin and the skeleton; the visual inspection system 18 is used to collect the appearance image of the weld after welding is completed, and transmit the data to the computer 19 for quality analysis; the visual inspection system 18 is connected to the computer 19, and the computer 19 is used to receive and process the weld image obtained by the visual inspection system 18, and give an image analysis algorithm to determine whether the weld quality is qualified.

[0056] Specifically, Figure 2 and Figure 3 As shown, the bearing support 1 includes a support mounting plate 20, a bearing mounting plate 21, a cross brace 22, a vertical brace 23 and a base plate 24, all of which are made of Q235 steel. The bearing support 1 is used for fixed connection between the device and the stir friction spot welding equipment, and at the same time, is used for connection with the reducer support 5 and the seat bearing 9.

[0057] like Figure 4 and Figure 5As shown, the reducer bracket 5 includes a reducer mounting plate 25, a reinforcing plate 26 and a side plate 27, all of which are made of Q235 steel. The reducer bracket 5 is connected to the bearing support 1 and is used to fix the worm gear reducer 6. Specifically, the reducer bracket 5 is fixedly installed on one side of the bearing support 1 by bolts 2, and a spring washer and a flat washer are set at the installation position.

[0058] like Figure 1 As shown, the reduction drive mechanism includes a worm gear reducer 6, which is fixed on a reducer bracket 5, and its input end is connected to a hand wheel 8. The hand wheel 8 is manually rotated to drive the worm to rotate, thereby driving the worm wheel to rotate, thereby realizing local movement or position adjustment of the equipment.

[0059] like Figure 6 and Figure 7 As shown, the flange 11 is mainly composed of a top plate 28, a reinforcing rib 29 and a ring 30. The top plate 28, the reinforcing rib 29 and the ring 30 are all made of Q235 steel. The flange 11 is connected to the round nut 10 and the tightening plate 13. By adjusting the position of the round nut 10 on the shaft 32, the axial position of the flange 11 can be adjusted. The tightening plate 13 is moved in the axial direction 32 by the bolt 12, so that the tightening plate 13 clamps the cabin skin 15 and the cabin frame 16.

[0060] like Figure 8 and Fig. 9 As shown, the drum assembly 14 is welded by a reducer mounting shaft 31, a shaft 32, a small flange 33, a positioning plate 34, a cone 35, and a large flange 36, wherein the reducer mounting shaft 31 is used for transmission connection with the worm gear reducer 6, the shaft 32 is coaxially transmission connected with the reducer mounting shaft 31, the cone 35 is fixed on the outer peripheral side of the shaft 32, the end of the cone 35 close to the worm gear reducer 6 is the small end, which is fixed by the small flange 33, and the end of the cone 35 away from the worm gear reducer 6 is the large end, which is fixed by the large flange 36. Considering the economy and reliability of the structure, the positioning plate 34, the small flange 33, and the large flange 36 are made of Q235 steel, while the reducer mounting shaft 31, the shaft 32, and the cone 35 are made of No. 20 steel.

[0061] The roller assembly 14 and the tensioning plate 13 are wedge-matched. Considering the operability of the relative movement between the two and the self-locking reliability of the working process, a 6° cone is used here. Since the two seat bearings 9 and the worm gear reducer 6 are connected in series on the same shaft 32, in order to reduce the additional resistance torque during the transmission process, the shoulder part of the shaft 32 that matches the seat bearing 9 here adopts the basic hole system, and the diameter is 100mm. The two shaft 32 shoulders are used as the reference, and the shaft 32 shoulders that match the worm gear reducer 6 are processed, and the basic hole system is also used. The processing size is 35mm in diameter and 0.05mm in roundness.

[0062] In the above embodiment, the deceleration drive mechanism cooperates with the spot welding tool 17 to accurately adjust the angle and position of the welding head under different welding paths to meet the multi-spot welding requirements of complex structures.

[0063] In the above embodiment, the clamping force of the wedge-shaped self-locking clamping mechanism can be adjusted according to the thickness of the welding material and the process requirements to ensure a close fit between the aluminum alloy skin and the frame and improve the consistency of the welding points.

[0064] In the above embodiment, the visual inspection system 18 collects solder joint images through a high-resolution industrial camera and uses a computer image processing algorithm to automatically determine the surface quality of the solder joint to ensure that the solder joint meets the preset standards.

[0065] In a specific embodiment, the outer envelope size of the aluminum alloy thin-walled cabin stir friction spot welding device is: length×width×height=1820mm×420mm×730mm.

[0066] The working principle of the spot welding device in this embodiment:

[0067] 1. Axial 32-direction friction stir spot welding: The cabin skin 15 is placed on the tensioning plate 13, and its end face is fitted with the end face of the roller assembly 14, and the cabin frame 16 on the inner side of the cabin skin 15 is placed in the clamping groove of the tensioning plate 13; the tensioning plate 13 and the roller assembly 14 are matched with wedge surfaces. During operation, the tensioning plate 13 is moved in the axial 32 direction relative to the roller assembly 14 through the screws on the flange 11, so that the tensioning plate 13 clamps the cabin skin 15. In this way, the cabin skin 15 and the cabin frame 16 can be stirred and friction spot welded in the axial 32 direction.

[0068] 2. Radial friction stir spot welding: The worm gear reducer 6 is controlled by the hand wheel 8 to rotate the cabin skin 15, the support plate 13 and the roller assembly 14 to achieve friction stir spot welding at different radial points of the cabin skin 15 and the cabin frame 16.

[0069] It should be understood that in actual applications, the reduction drive mechanism can also be other reduction drive structures or mechanical devices that can convert the high-speed rotational motion of the input shaft 32 into the low-speed, high-torque rotational motion of the output shaft 32. For example, it can be a gear reducer, a planetary gear reducer, etc.

[0070] Embodiment 2

[0071] Embodiment 2 of the present invention provides a stir friction spot welding method for a 2219-T851 aluminum alloy thin-walled cabin body, which is based on the stir friction spot welding device for an aluminum alloy thin-walled cabin body described in Embodiment 1. The welding method is suitable for a 2219-T851 aluminum alloy thin-walled cabin body with a diameter of 3.5m and a height of 2.8m, a skin thickness of 1.8mm, a frame of a 2219 aluminum alloy profile, and all welded joints are stir friction spot welded joints. The spot welding method comprises the following steps:

[0072] Step S1: Cleaning before welding

[0073] Before welding, the welding areas of the aluminum alloy cabin skin 15 and the cabin frame 16 are mechanically polished using 400# sandpaper to remove surface oxide film and dirt; then, industrial ethanol is used to wipe the welding parts to ensure that the surface is free of oil, impurities and dust, so as to avoid defects such as pores, inclusions or cracks during the welding process.

[0074] Step S2: Clamping the workpiece

[0075] The cabin assembly (cabin skin 15 and cabin frame 16) is fixed in the stir friction spot welding device, and the workpiece is clamped by the flange 11 and the support plate 13. By adjusting the clamping force, it is ensured that the workpiece does not deform or deflect during the welding process. The wedge-shaped self-locking clamping mechanism can provide a stable clamping force and can be appropriately adjusted according to the workpiece size and welding process requirements.

[0076] Step S3: Welding path positioning

[0077] The position of the roller assembly 14 is adjusted by the worm gear reducer 6 to accurately align the welding spot area. The high-precision transmission system can ensure that the welding path meets the preset requirements and ensure the uniformity and consistency of the welding spot.

[0078] Step S4: Execute welding

[0079] During welding, welding parameters can be set within the following ranges:

[0080] Spot welding tool 17 rotation speed: 2000-3500 revolutions per minute (rpm);

[0081] Stirring needle insertion depth: 1.2-2.2 mm;

[0082] Welding time: 3.0-5.0 seconds / point.

[0083] In this embodiment, according to the material properties of the 2219-T851 aluminum alloy thin-walled cabin, the welding parameters are optimized to obtain the best welding quality. The specific parameter settings are as follows:

[0084] Spot welding tool 17 rotation speed: 2800-2900 revolutions per minute (rpm);

[0085] Pressing depth: 1.8-2.0 mm;

[0086] Welding time: 4.0-4.2 seconds / point;

[0087] After the welding machine is started, the spot welding tool 17 rotates at high speed and slowly inserts into the welding part, so that the base material is plasticized to a hard state by friction heat generation, and a high-strength connection is formed during the stirring process.

[0088] Step S5: Cooling after welding

[0089] After welding is completed, the weld is cooled naturally at room temperature to avoid residual stress or microcracks in the welding area due to rapid cooling; the workpiece is kept clamped during the cooling process to prevent the weld joint from deforming due to thermal contraction.

[0090] Step S6: Post-welding quality inspection

[0091] After the welding cooling is completed, the visual inspection system 18 is used to collect the appearance image of the weld point and transmit the data to the computer 19. The computer 19 automatically analyzes the shape of the weld point to determine whether the weld point meets the welding quality requirements; if the inspection result is qualified, the welding device is adjusted, moved to the next weld point, and the welding process is repeated; if the inspection is unqualified, the system automatically prompts to re-weld or repair to ensure that all welds meet the design standards; through point-by-point inspection, welding defects can be effectively reduced, welding quality consistency can be improved, scrap rate can be reduced, and it can be ensured that the welds meet aerospace-grade quality requirements.

[0092] Compared with the prior art, this embodiment discloses at least the following beneficial effects: This embodiment optimizes the welding device structure and welding process for the welding requirements of 2219-T851 aluminum alloy thin-walled cabin, and significantly improves the welding quality and efficiency. Compared with the traditional welding method, the tensile strength of the welded joint is increased to 92% of the strength of the parent material, the weld structure is uniform, there are no keyhole defects, and the mechanical properties are stable after welding. After adopting the point-by-point welding + real-time detection mode, the quality consistency of the weld point is improved by 35%, and the welding qualification rate reaches more than 98%, which greatly reduces the rework rate caused by welding defects. At the same time, the optimized worm gear reduction mechanism improves the welding positioning accuracy, reduces the welding path adjustment time by 30%, and improves the overall welding efficiency by 40%. In addition, the present invention adopts the stir friction welding process to avoid the high-temperature oxidation and welding spatter problems of traditional fusion welding, making the welding process more environmentally friendly, reducing the welding energy consumption by 18%, and meeting the requirements of green manufacturing.

[0093] Embodiment 3

[0094] Embodiment 3 of the present invention provides a stir friction spot welding method for a 2195-T84 aluminum-lithium alloy thin-wall cabin body, and the method uses the aluminum alloy thin-wall cabin stir friction spot welding device described in Embodiment 1. The spot welding method is suitable for a 2195-T84 aluminum-lithium alloy thin-wall cabin body with a skin thickness of 1.2 mm and a skeleton of a 2195 aluminum-lithium alloy profile. The diameter of the welded aerospace cabin scale model is 1.6 m and the height is 1.2 m. The welded joints are all stir friction spot welding joints. The spot welding method comprises the following steps:

[0095] Step 1: Cleaning before welding

[0096] Use 600# fine sandpaper to lightly grind the contact surface of the aluminum-lithium alloy cabin skin 15 and the cabin frame 16 to remove the surface oxide film to avoid affecting the welding quality; then use dust-free gauze dipped in industrial ethanol to thoroughly wipe the welding area to ensure that there is no oil, dust or other impurities to prevent pores or inclusions during welding.

[0097] Step S2: Clamping the workpiece

[0098] The scaled model of the spacecraft cabin is fixed in the aluminum alloy thin-wall cabin friction stir spot welding device of the present invention, and the positions of the flange 11 and the support plate 13 are adjusted so that the cabin skin 15 and the cabin frame 16 can fit firmly and ensure that the workpiece will not be displaced or deformed during the welding process.

[0099] Step S3: Welding path positioning

[0100] The position of the roller assembly 14 is adjusted by the worm gear reducer 6 to accurately align the welding point area. The high-precision transmission system ensures that the welding path meets the preset requirements and ensures the uniformity and consistency of the welding points.

[0101] Step S4: Execute welding

[0102] According to the material properties of 2195-T84 aluminum-lithium alloy thin-walled cabin, the welding parameters are optimized to obtain the best welding quality. The specific parameter settings are as follows:

[0103] The rotation speed of the spot welding tool 17 is 2950-3050 revolutions per minute (rpm);

[0104] The indentation depth is set to 1.2-1.5 mm;

[0105] The welding time is set to 3.5-3.8 seconds / point;

[0106] The welding machine is started, and the spot welding tool 17 is slowly inserted into the welding position after rotating at a high speed, so that the base material reaches a plastic state through frictional heat generation, and a high-strength connection is formed during the stirring process.

[0107] Step S5: Cooling after welding

[0108] After welding is completed, the weld is cooled naturally at room temperature to avoid residual stress or microcracks in the welding area due to rapid cooling. During the cooling process, the workpiece is kept clamped to prevent the weld joint from deforming due to thermal contraction.

[0109] Step S6: Post-welding quality inspection

[0110] After the welding cooling is completed, the visual inspection system 18 is used to collect the appearance image of the weld point and transmit the data to the computer 19. The computer 19 automatically analyzes the shape of the weld point to determine whether the weld point meets the welding quality requirements; if the inspection result is qualified, the welding device is adjusted, moved to the next weld point, and the welding process is repeated; if the inspection is unqualified, the system automatically prompts to re-weld or repair to ensure that all welds meet the design standards; through point-by-point inspection, welding defects can be effectively reduced, welding quality consistency can be improved, scrap rate can be reduced, and it can be ensured that the welds meet aerospace-grade quality requirements.

[0111] Compared with the prior art, this embodiment discloses at least the following beneficial effects: This embodiment optimizes the welding process parameters and improves the welding stability and joint mechanical properties in view of the welding requirements of the 2195-T84 aluminum-lithium alloy thin-walled cabin. The tensile strength of the welded joint reaches 90% of the strength of the parent material, the weld surface is smooth, the weld is dense, there are no obvious microcracks and pores, and the quality stability of the weld is improved by 30%. Compared with the traditional welding process, the intelligent detection system of this embodiment improves the weld defect recognition capability, so that the welding pass rate reaches more than 96%, the welding rework rate is reduced by 50%, and the material waste in the production process is reduced. Through precise welding path control and optimized worm gear positioning system, the welding time is shortened by 25% and the overall production efficiency is improved by 35%. At the same time, the stir friction welding method of the present invention has lower energy consumption, which can reduce the power consumption by 22% compared with the fusion welding technology, and extend the service life of the equipment by 45%, which is suitable for high reliability and high efficiency aerospace manufacturing needs.

[0112] The details not described in detail in the present invention are all conventional technical means known to those skilled in the art.

[0113] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0114] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A friction stir spot welding device for aluminum alloy thin-walled cabin, characterized in that: include: Two bearing supports (1) arranged at intervals and used to support the device body; A roller assembly (14) is rotatably connected between the two bearing supports (1), the roller assembly (14) comprising a reducer mounting shaft (31), a shaft (32), a small flange (33), a positioning plate (34), a cone cylinder (35) and a large flange (36), wherein the small end of the cone cylinder (35) is fixed by the small flange (33), and the large end is fixed by the large flange (36); A reduction drive mechanism, comprising a worm gear reducer (6), wherein the worm gear reducer (6) is fixed to a bearing support (1) on one side via a reducer bracket (5) and is drivingly connected to a roller assembly (14) for controlling a welding path; A wedge-shaped self-locking clamping mechanism comprises a flange (11) and a clamping plate (13), wherein the flange (11) and the clamping plate (13) are bolted together and are used to clamp a welding workpiece; A spot welding tool (17) is used to perform a friction stir spot welding operation.

2. The aluminum alloy thin-wall cabin friction stir spot welding device according to claim 1 is characterized in that: The roller assembly (14) and the tightening plate (13) are in wedge-shaped cooperation.

3. The aluminum alloy thin-wall cabin friction stir spot welding device according to claim 2 is characterized in that: The cone angle of the wedge fit is 6°.

4. The aluminum alloy thin-wall cabin friction stir spot welding device according to claim 1, 2 or 3, characterized in that: It also includes a visual inspection system (18) for collecting images of solder joints and performing quality analysis via a computer (19); the visual inspection system (18) collects images of solder joints via a high-resolution industrial camera and automatically determines the surface quality of the solder joints using a computer image processing algorithm.

5. The aluminum alloy thin-wall cabin friction stir spot welding device according to claim 1, characterized in that: The reduction drive mechanism further comprises a hand wheel (8), wherein the hand wheel (8) is connected to the input end of the worm gear reducer (6) and is used for manual drive adjustment.

6. The aluminum alloy thin-wall cabin friction stir spot welding device according to claim 1, characterized in that: The flange (11) comprises a top plate (28), a reinforcing rib (29) and a circular ring (30). The flange (11) is connected to a tightening plate (13) via a circular nut (10) and a second bolt (12). The axial position of the flange (11) can be adjusted by adjusting the position of the circular nut (10) on the shaft (32).

7. A friction stir spot welding method, according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1: cleaning the surface of the welding area of ​​the aluminum alloy thin-walled cabin to remove oxide film and impurities; Step S2: clamping the cabin skin (15) and the cabin frame (16) by means of a wedge-shaped self-locking clamping mechanism; Step S3: adjusting the position of the roller assembly (14) through the worm gear reducer (6) to accurately locate the welding point; Step S4: starting the spot welding tool (17), setting the rotation speed to 2000-3500 rpm, the pressing amount to 1.2-2.2 mm, and the welding time to 3.0-5.0 seconds / point, and performing friction stir spot welding; Step S5: Cool naturally after welding and keep the clamping state to prevent deformation; Step S6: Perform quality analysis on the solder joints, and proceed to the next solder joint if they are qualified.

8. The friction stir spot welding method according to claim 7, characterized in that: In step S6, a visual inspection system (18) is used to perform quality analysis on the solder joints.

9. The friction stir spot welding method according to claim 7, characterized in that: In step S4, when the welding material is 2219-T851 aluminum alloy, the rotation speed is set to 2800-2900 rpm, the pressing amount is set to 1.8-2.0 mm, and the welding time is set to 4.0-4.2 seconds / point.

10. The friction stir spot welding method according to claim 7, characterized in that: In step S4, when the welding material is 2195-T84 aluminum-lithium alloy, the rotation speed is set to 2950-3050 rpm, the pressing amount is set to 1.2-1.5 mm, and the welding time is set to 3.5-3.8 seconds / point.

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