Welding clamp, welding system and welding method for special-shaped thin-wall metal air bag

Abstract

The invention discloses a welding clamp, a welding system and a welding method for a special-shaped thin-wall metal air bag, and belongs to the technical field of thin-wall welding. The problem that in the prior art, a welding device and a welding method are not suitable for welding forming of a small-size special-shaped thin-wall metal air bag with an irregular weld joint structure is solved. A limiting groove is formed in the top of the supporting bottom plate, a back protection groove and an air nozzle groove are formed in the bottom of the limiting groove, the back protection groove is of a closed-loop structure, the shape of the cross section of the back protection groove is matched with the shape of a welding seam of the metal air bag, and the supporting bottom plate is further provided with a first air inlet channel and a first air outlet channel which are communicated with the back protection groove. The mode of replacing a welding seam cover plate is adopted, the welding seams at different positions of the thin-wall metal air bag are subjected to constraint welding, the mode of two-way laser staggered welding is used for replacing single-way laser corner welding at the geometric closed positions of the welding seams, ablation and fusion penetration caused by vertex heat accumulation are effectively avoided, and welding forming of irregular welding seams is achieved.

Description

Technical Field

[0001] The invention relates to a welding fixture, a welding system and a welding method for a special-shaped thin-wall metal airbag, belonging to the technical field of thin-wall welding. Background Art

[0002] Metal airbags are a new type of high-power-to-weight drive device. In the aerospace field, they can be used for a variety of aerospace vehicle variants and separation actions, such as rocket stage separation, fairing separation, aircraft wing folding, weapon release and bomb release. Compared with traditional drive devices, metal airbags are small in size and light in weight, and have significant advantages such as high output power-to-volume ratio and rapid response. At the same time, metal airbags are a typical small-sized thin-walled structure. The initial structure before inflation is flat. It is formed by stacking and welding two layers of metal foil through a specific welding process. In order to improve certain mechanical properties of the metal airbag after inflation, a set of opposite sides of the metal airbag are often designed as concave arcs or other special curves to form a special-shaped thin-walled metal airbag, so it has an irregular and discontinuous weld structure.

[0003] Laser welding is an efficient and precise welding method that uses a high-energy-density laser beam as a heat source. Based on its unique advantages, it has been widely used in the precision welding of various parts. However, for structures such as metal airbags, due to the inherent characteristics of irregular weld shapes and thin and flexible parent materials, defects such as spatter and pores are easily generated during laser lap welding, affecting the airtightness of the airbag; on the other hand, the parent material may also cause warping, ablation, and melt-through due to thermal deformation and uneven thermal stress. At present, there is no mature welding process that can be applied. In the prior art, there are welding processes and welding fixtures for conventional rectangular thin-walled metal airbags. Specifically, a laser lap welding bidirectional constraint fixture is used to form a continuous straight seam weld to achieve sealing welding along the four sides of the metal airbag. However, the structure of this fixture is relatively complex. In order to simultaneously achieve the welding of the air nozzle and the four sides, it is necessary to add multiple limit cover plates and combine bolts and other structures to achieve a close fit between the upper wall parent material and the lower wall parent material of the airbag. For small-sized thin-walled structures, when all welds are set on the same upper pressure cover plate, due to size limitations, there is not enough space to add bolts and other connecting structures. The circular hole at the air nozzle position in the middle of the cover plate will be suspended, which is not conducive to clamping and positioning. At the same time, a certain pressure covering area will be sacrificed due to the large gap. More importantly, the existing welding process for rectangular metal airbag base materials is completed by the laser gun head. When used for welding special-shaped thin-walled metal airbags with irregular and discontinuous weld structures, ablation and melt-through caused by vertex heat accumulation are very likely to occur at the geometric closure of the weld, and the thermal stress distribution at the weld position is uneven, which seriously affects the welding quality.

[0004] Therefore, there is an urgent need for a welding device and a welding method to ensure that the weld is continuous and reliable, has good airtightness, and realizes the welding forming of small-sized special-shaped thin-walled metal airbags. Summary of the invention

[0005] The present invention aims to solve the above technical problems and further provides a welding fixture, a welding system and a welding method for special-shaped thin-walled metal airbags.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] A welding fixture for a special-shaped thin-walled metal airbag comprises a supporting base plate, a first weld cover plate and a second weld cover plate, wherein a limiting groove is provided on the top of the supporting base plate, a back protection groove and an air nozzle groove are provided on the bottom of the limiting groove, the airbag air nozzle is located in the air nozzle groove, the back protection groove is a closed-loop structure and its cross-sectional shape is arranged in accordance with the weld shape of the metal airbag, a first air inlet channel and a first air outlet channel connected to the back protection groove are also provided on the supporting base plate, first to third weld through holes are provided on the first weld cover plate, corresponding to the welds at the left and right ends of the metal airbag and the circular weld connecting the airbag nozzle and the lower wall base material of the airbag, and fourth to fifth weld through holes are provided on the second weld cover plate The holes correspond to the welds at the front and rear ends of the metal airbag respectively. The bottom end of the first weld cover plate is processed with a first limiting boss corresponding to the limiting groove, and the bottom end of the second weld cover plate is processed with a second limiting boss corresponding to the limiting groove. When welding the welds at the left and right ends of the metal airbag and the circular weld connecting the airbag nozzle and the lower wall parent material of the airbag, the lower wall parent material of the airbag is clamped between the first limiting boss and the limiting groove of the supporting bottom plate, and the first weld cover plate is fixedly connected to the supporting bottom plate. When welding the welds at the front and rear ends of the metal airbag, the upper wall parent material of the airbag and the lower wall parent material of the airbag are stacked between the second limiting boss and the limiting groove of the supporting bottom plate, and the second weld cover plate is fixedly connected to the supporting bottom plate.

[0008] Furthermore, a back protection block is embedded in the back protection groove, and the back protection block is a closed-loop structure. A weld groove is processed on the upper portion of the back protection block, and a second air inlet channel and a second air outlet channel connected to the weld groove are processed on the side wall of the back protection block, and the second air inlet channel is arranged opposite to the first air inlet channel, and the second air outlet channel is arranged opposite to the first air outlet channel.

[0009] Furthermore, the material of the supporting bottom plate, the first weld cover plate and the second weld cover plate are all 06Cr19Ni10, and the material of the back protection block is H61.

[0010] Furthermore, the width of the weld groove is greater than the spot diameter of the laser, and the third weld through hole is a circular hole and its diameter is greater than the diameter of the gas nozzle groove.

[0011] Furthermore, the longitudinal sections of the first weld bead through hole, the second weld bead through hole, the fourth weld bead through hole and the fifth weld bead through hole are all Y-shaped hole structures.

[0012] Furthermore, the depth of the limiting groove and the height of each limiting boss are both 1 mm, and the plane size of the limiting groove is the same as the airbag lower wall mother material and the airbag upper wall mother material.

[0013] Furthermore, the first air inlet channel and the first air outlet channel are symmetrically arranged at the front and rear sides of the support base plate.

[0014] Furthermore, the cross-sections of the limiting groove and each limiting boss are rectangular structures.

[0015] A welding system includes the above-mentioned welding fixture, and also includes a movement and control system, a laser source system, a welding laser gun head and a shielding gas source, wherein the welding laser gun head is installed on the movement and control system and connected to the laser source system through an optical fiber, and the first air inlet channel and the first air outlet channel in the welding fixture are connected to the shielding gas source through gas pipelines.

[0016] A welding method for a special-shaped thin-walled metal airbag using the above welding system comprises the following steps:

[0017] Step 1: Connect the shielding gas source to form a shielding gas channel, open the shielding gas source to allow the shielding gas to flow through the shielding gas channel, completely cover the weld laser routing and circulate;

[0018] Step 2: embed the airbag nozzle into the nozzle groove, embed the airbag lower wall base material into the limiting groove, install the first weld cover plate and the supporting bottom plate, turn on the laser source system, use the movement and control system to move the welding laser gun head to the top of the third weld pass through hole, and start welding the first weld to overlap and weld the airbag nozzle and the airbag lower wall base material into one;

[0019] Step 3: remove the first weld cover plate, stack the airbag upper wall base material on the airbag lower wall base material and reinstall the first weld cover plate and the supporting bottom plate, move the welding laser gun head to the first weld through hole, start welding the second weld, then move the welding laser gun head to the second weld through hole, and start welding the third weld;

[0020] Step 4: remove the first weld cover plate, replace and install the second weld cover plate on the supporting bottom plate, move the welding laser gun head to the top of the fourth weld through hole, start welding the fourth weld, then move the welding laser gun head to the top of the fifth weld through hole, start welding the fifth weld, and complete the welding. The second to fifth welds are cross-closed, and the lower wall parent material of the airbag and the upper wall parent material of the airbag are overlap-welded into one;

[0021] Step 5: Trim or cut along the periphery of the weld to form a special-shaped thin-walled metal airbag with single-side air intake.

[0022] Compared with the prior art, the present invention has the following effects:

[0023] The welding fixture of the present invention comprises two weld cover plates, wherein the first weld cover plate is placed above the supporting base plate, and is used to realize the welding of a circular weld between the airbag lower wall base material and the airbag nozzle, and the welding of two left-right symmetrical welds between the airbag upper wall base material and the airbag lower wall base material; the second weld cover plate is placed above the supporting base plate 1, and is used to realize the welding of two symmetrical welds between the airbag upper wall base material and the airbag lower wall base material; the two cover plates provide sufficient clamping force for specific welds of the bag wall in different processes. Avoid setting all welds on the same welding cover plate, and then prevent the circular hole at the airbag nozzle position in the middle of the weld cover plate from being suspended, which is more conducive to clamping and positioning, and also effectively avoids sacrificing a certain pressing area due to a large gap.

[0024] By replacing the weld cover plate, constrained welding is performed on the welds at different positions of the thin-walled metal airbag. At the geometric closure of the weld, two laser staggered weldings are used to replace the single laser corner welding, which effectively avoids the ablation and melt-through caused by the heat accumulation at the vertex and realizes the welding formation of irregular welds.

[0025] During the welding process, the welding sequence has a significant impact on the deformation, which in turn affects the quality of the weld. Since the airbag nozzle welding position is located between two layers of foil, welding must be performed first. The present invention determines the closed-loop welding sequence of welding between the airbag nozzle and the airbag lower wall parent material → two symmetrical left and right special-shaped welds → two symmetrical front and back straight welds, thereby reducing the unevenness of the thermal stress distribution at the weld position.

[0026] The invention has a simple structure, concise process, reliable and continuous welds, good air tightness, and can realize welding forming of special-shaped thin-walled metal airbags with irregular welds. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a three-dimensional structural schematic diagram of the welding system of the present invention;

[0028] Figure 2 It is an exploded schematic diagram of a welding fixture for a special-shaped thin-walled metal airbag of the present invention;

[0029] Figure 3 A top view schematic diagram of the supporting base plate;

[0030] Figure 4 for Figure 3 AA section view (not to scale);

[0031] Figure 5 is a top view schematic diagram of the back protection block;

[0032] Figure 6 for Figure 5 BB section diagram (not to scale);

[0033] Figure 7 is a bottom view schematic diagram of the first weld cover plate;

[0034] Figure 8 for Figure 7 Schematic diagram of CC section (not to scale);

[0035] Fig. 9 is a bottom view schematic diagram of the second weld cover plate;

[0036] Fig.10 for Fig. 9 DD section diagram (not to scale);

[0037] Fig.11 It is a bottom-up schematic diagram of a special-shaped thin-walled metal airbag;

[0038] Fig.12 It is a schematic diagram of the position of the first weld in step 2 of the welding method of the present invention;

[0039] Fig.13 It is a schematic diagram of the positions of the second weld and the third weld in step three of the welding method of the present invention;

[0040] Fig.14 Schematic diagram of the positional relationship of the second to fifth welds in step four of the welding method of the present invention.

[0041] In the figure:

[0042] 100, airbag nozzle; 101, airbag lower wall base material; 102, airbag upper wall base material; 103, movement and control system; 104, laser source system; 105, welding laser gun head; 106, shielding gas source; 107, welding fixture; 1, support base plate; 1-1, limit groove; 1-2, back protection groove; 1-3, air nozzle groove; 1-4, first air inlet channel; 1-5, first air outlet channel; 2, first Weld cover plate; 2-1, first weld through hole; 2-2, second weld through hole; 2-3, third weld through hole; 2-4, first limiting boss; 3, second weld cover plate; 3-1, fourth weld through hole; 3-2, fifth weld through hole; 3-3, second limiting boss; 4, back protection block; 4-1, weld groove; 4-2, second air inlet channel; 4-3, second air outlet channel; 5, air inlet connector; 6, air outlet connector. DETAILED DESCRIPTION

[0043] Specific implementation method 1: Combination Figures 1 to 14 This embodiment is explained, and the technical scheme in the embodiment of the present invention is clearly and completely described. Obviously, the described embodiment is only a part of the embodiment of the present invention, rather than all the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] It should be noted that the descriptions of the present invention regarding directions such as "front", "back", "left", "right", "inside", "outside", "left side", "right side", "upper", "lower", "top", "bottom", etc. are all defined based on the relationship between the orientations or positions shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structure must be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. In the description of the present invention, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0045] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] A welding fixture for a special-shaped thin-walled metal airbag comprises a supporting base plate 1, a first weld cover plate 2 and a second weld cover plate 3, wherein a limiting groove 1-1 is provided on the top of the supporting base plate 1, a back protection groove 1-2 and an air nozzle groove 1-3 are provided at the bottom of the limiting groove 1-1, an airbag air nozzle 100 is located in the air nozzle groove 1-3, the back protection groove 1-2 is a closed-loop structure and its cross-sectional shape is arranged in accordance with the weld shape of the metal airbag, a first air inlet channel 1-4 and a first air outlet channel 1-5 connected to the back protection groove 1-2 are also provided on the supporting base plate 1, first to third weld through holes 2-3 are provided on the first weld cover plate 2, which respectively correspond to the welds at the left and right ends of the metal airbag and the circular weld connecting the airbag air nozzle 100 and the lower wall base material 101 of the airbag, and fourth to fifth weld through holes 2-3 are provided on the second weld cover plate 3 The through holes 3-2 correspond to the welds at the front and rear ends of the metal airbag respectively. The bottom end of the first weld cover plate 2 is processed with a first limiting boss 2-4 corresponding to the limiting groove 1-1, and the bottom end of the second weld cover plate 3 is processed with a second limiting boss 3-3 corresponding to the limiting groove 1-1. When welding the welds at the left and right ends of the metal airbag and the circular weld connecting the airbag nozzle 100 and the lower wall mother material 101 of the airbag, the lower wall mother material 101 of the airbag is clamped between the first limiting boss and the limiting groove 1-1 of the supporting bottom plate 1, and the first weld cover plate is fixedly connected to the supporting bottom plate 1. When welding the welds at the front and rear ends of the metal airbag, the upper wall mother material 102 of the airbag and the lower wall mother material 101 of the airbag are overlapped between the second limiting boss and the limiting groove 1-1 of the supporting bottom plate 1, and the second weld cover plate is fixedly connected to the supporting bottom plate 1.

[0047] The structure of the thin-walled metal airbag is a thin-walled airbag formed by overlapping and welding two layers of metal foil materials, an upper wall mother material 102 and a lower wall mother material 101 of the airbag, wherein the geometric center of the airbag lower wall mother material 101 is punched and overlapped and welded with the airbag nozzle 100. The airbag nozzle 100 is a structure similar to a ferrule nut, with a hexagonal prism with an internal thread at the lower end and a circular hole in the center of the upper surface for ventilation. Based on the welding fixture and welding method provided by the present invention, the three are welded into a whole and trimmed or cut along the periphery of the weld to form a metal bag structure with single-sided air intake.

[0048] In this embodiment, the shape of the weld seams of a thin-walled metal airbag is described by taking the shape of the weld seams of the left and right weld seams as arcs and the front and rear weld seams as straight segments as an example, but it is not limited to this thin-walled metal airbag structure.

[0049] The air nozzle groove 1-3 is a circular groove, which is used to adapt to the external structure of the airbag air nozzle 100. Specifically, the inner diameter of the air nozzle groove 1-3 is the same as the diameter of the circumscribed circle of the bottom polygonal structure of the metal airbag air nozzle 100, and the depth of the air nozzle groove 1-3 is the same as the height of the metal airbag air nozzle 100.

[0050] The support base plate 1 is placed at the bottom of the welding fixture 107 to support and fix other components.

[0051] The back protection groove 1-2 is used to guide the shielding gas, accelerate the cooling of the weld and prevent oxidation on the back of the weld. The groove width of the back protection groove 1-2 is greater than the weld width on the metal airbag. The curvature of the inner wall of the back protection groove 1-2 at the position corresponding to the irregular weld structure on the metal airbag can be less than the curvature of the weld of the metal airbag, so as to leave enough space for the welding process. The arc radius at each corner position on the back protection groove 1-2 is greater than the arc radius at the weld corner of the metal airbag at the corresponding position.

[0052] The first weld bead through hole 2-1 and the second weld bead through hole 2-2 correspond to the welding of irregular welds at the left and right ends of the thin-walled metal airbag respectively; the third weld bead through hole 2-3 corresponds to the circular weld connecting the airbag nozzle 100 and the airbag lower wall base material 101.

[0053] The welding fixture of the present invention comprises two weld cover plates, wherein the first weld cover plate 2 is placed above the supporting base plate 1, and is used to realize the welding of a circular weld between the airbag lower wall base material 101 and the airbag nozzle 100, and the welding of two left-right symmetrical welds between the airbag upper wall base material 102 and the airbag lower wall base material 101; the second weld cover plate 3 is placed above the supporting base plate 1, and is used to realize the welding of two symmetrical welds between the airbag upper wall base material 102 and the airbag lower wall base material 101; the two cover plates provide sufficient clamping force for specific welds of the bag wall in different processes. Avoid setting all welds on the same welding cover plate, and then prevent the circular hole at the position of the airbag nozzle 100 in the middle of the weld cover plate from being suspended in the air, which is more conducive to clamping and positioning, and also effectively avoids sacrificing a certain pressing area due to a large gap.

[0054] The shape of the thin-walled metal airbag in the present invention is: the left and right ends are symmetrical curved structures, and the front and rear ends are symmetrical straight-line structures. The airbag nozzle 100 is installed on the lower wall mother material 101 of the metal airbag.

[0055] The first limiting boss 2-4 and the second limiting boss 3-3 respectively correspond to and cooperate with the limiting groove 1-1 on the supporting base plate 1 to achieve clamping and limiting of the metal airbag base material.

[0056] The first air inlet channel 1-4 and the first air outlet channel 1-5 are used for the introduction and discharge of protective gas.

[0057] The fixing method between the supporting base plate 1 and the first weld cover plate 2 and between the supporting base plate 1 and the second weld cover plate 3 can be achieved by a number of threaded fasteners or by magnetic attraction, as long as the constraint and clamping force between the supporting base plate 1 and the first weld cover plate 2 or the supporting base plate 1 and the second weld cover plate 3 can be provided.

[0058] When the supporting base plate 1 and the two weld cover plates are fixedly connected by a plurality of threaded fasteners respectively, a plurality of first threaded holes are opened on the supporting base plate 1 along its circumference, a plurality of second threaded holes are opened on the first weld cover plate 2 along its circumference, a plurality of third threaded holes are opened on the third weld cover plate along its circumference, and the plurality of second threaded holes are arranged in one-to-one correspondence with the plurality of first threaded holes, and the plurality of third threaded holes are arranged in one-to-one correspondence with the plurality of first threaded holes, and the number of first threaded holes is preferably four.

[0059] The present invention uses the first weld cover plate 2 and the second weld cover plate 3 to perform constrained welding on the welds at different positions of the metal airbag. At the geometrically closed position of the weld, two laser staggered weldings are used to replace the single laser corner welding, which effectively avoids ablation and melt-through caused by vertex heat accumulation and realizes the welding formation of irregular welds.

[0060] The present invention provides limiting and clamping force for the thin-walled base material to be welded by cooperating the limiting boss and the limiting groove 1-1 between the weld cover plate and the supporting bottom plate 1, thereby preventing the foil from rotating around the nozzle position and causing the weld position to deviate.

[0061] A back protection block 4 is embedded in the back protection groove 1-2. The back protection block 4 is a closed-loop structure. A weld groove 4-1 is processed on the upper part of the back protection block 4. The side wall of the back protection block 4 is processed with a second air inlet channel 4-2 and a second air outlet channel 4-3 connected to the weld groove 4-1. The second air inlet channel 4-2 is arranged opposite to the first air inlet channel 1-4, and the second air outlet channel 4-3 is arranged opposite to the first air outlet channel 1-5. In this design, the first air inlet channel 1-4 is connected to the second air inlet channel 4-2, and the protective gas enters the weld groove 4-1 through the first air inlet channel 1-4 and the second air inlet channel 4-2. The support base plate 1 and the back protection block 4 are designed to be split, which has lower requirements on the material of the support base plate 1. Only the material of the back protection block 4 with high thermal conductivity and corrosion resistance can be selected, so as to ensure the quality of the weld while effectively controlling the processing cost. The shape of the weld groove 4-1 is determined according to the laser routing of the weld. The width of the weld groove 4-1 is larger than the spot diameter of the laser and has a certain margin, preferably 2 mm. The three-dimensional size of the back protection groove 1-2 is the same as that of the back protection block 4. The back protection groove 1-2 and the back protection block 4 are transitionally matched.

[0062] The materials of the support bottom plate 1, the first weld cover plate 2 and the second weld cover plate 3 are all 06Cr19Ni10, and the material of the back protection block 4 is H61. With such a design, the copper alloy has high thermal conductivity and corrosion resistance, which helps to reduce the local temperature and prevent overheating, thereby protecting the microstructure and mechanical properties of the weld area. Therefore, the support bottom plate 1 and the back protection block 4 adopt a split design, which effectively dredges the protective gas while controlling the processing cost, and ensures the weld quality of the back of the stack welding.

[0063] The width of the weld groove 4-1 is larger than the spot diameter of the laser, and the third weld through hole 2-3 is a circular hole with a diameter larger than the diameter of the nozzle groove 1-3. With such a design, a 2 mm margin is left radially between the third weld through hole 2-3 and the nozzle groove 1-3.

[0064] The longitudinal sections of the first weld bead through hole 2-1, the second weld bead through hole 2-2, the fourth weld bead through hole 3-1 and the fifth weld bead through hole 3-2 are all Y-shaped hole structures. With such a design, the laser gun head is shot from the top of the Y-shaped hole structure and focused on the plane of the base material to be welded. The surface of the weld cover plate corresponding to the lower end of the Y-shaped hole structure contacts the base material to be welded and provides a clamping force. Since the thin-walled base material will inevitably be affected by the heat input and undergo local warping during the welding process, when the constraint is insufficient, an air gap will appear between the two layers of foil, causing the upper layer to melt through. Therefore, it is usually necessary to make the clamping area of ​​the weld cover plate on the thin-walled base material as large as possible, that is, the weld bead through hole is as narrow as possible to suppress warping. However, due to the certain thickness of the weld cover plate, the weld bead through hole is too narrow to make it difficult for the laser gun head to focus on the plane of the base material to be welded. Therefore, the present invention designs the longitudinal sections of the first weld bead through hole 2-1, the second weld bead through hole 2-2, the fourth weld bead through hole 3-1 and the fifth weld bead through hole 3-2 on the weld cover plate as a Y-shaped hole structure, so that the weld cover plate can provide sufficient pressing force to the thin-walled base material to prevent warping, while achieving accurate focusing of the laser at the position to be welded. Preferably, the upper cone angle of the Y-shaped hole structure is 60°, and the depth of the lower straight hole section is 9 mm.

[0065] The depth of the limiting groove 1 - 1 and the height of each limiting boss are both 1 mm, and the plane size of the limiting groove 1 - 1 is the same as the airbag lower wall mother material 101 and the airbag upper wall mother material 102 .

[0066] The first air inlet channel 1-4 and the first air outlet channel 1-5 are symmetrically arranged on the front and rear sides of the support base plate 1. With such a design, the protective gas can be evenly filled in the cavity of the groove of the back protection block.

[0067] The cross sections of the limiting groove 1 - 1 and each limiting boss are rectangular structures.

[0068] A welding system includes the above-mentioned welding fixture 107, a movement and control system 103, a laser source system 104, a welding laser gun head 105 and a shielding gas source 106, wherein the welding laser gun head 105 is installed on the movement and control system 103 and is connected to the laser source system 104 through an optical fiber, and the first air inlet channel 1-4 and the first air outlet channel 1-5 in the welding fixture 107 are respectively connected to the shielding gas source 106 through gas pipelines.

[0069] The gas pipeline is connected to the first air inlet channel 1-4 and the first air outlet channel 1-5 through the air inlet connector 5 and the air outlet connector 6 respectively, and the air inlet connector 5 and the first air inlet channel 1-4 and the air outlet connector 6 and the first air outlet channel 1-5 are connected by threads. The source light source system adopts a semiconductor laser, and the movement and control system 103 adopts a robot arm with more than six axes and a dual-axis positioner to provide a continuous flat-top laser as a heat source. It provides the necessary freedom of movement and precision for the welding process, and at the same time uses a robot control system to realize the integrated motion control of the entire welding equipment. The shielding gas source 106 adopts an argon gas storage cylinder. The specific structures of the movement and control system 103, the laser source system 104, the welding laser gun head 105 and the shielding gas source 106 described in the present invention are all prior art, and their specific structural composition will not be repeated here.

[0070] A welding method for a special-shaped thin-walled metal airbag using the above welding system comprises the following steps:

[0071] Step 1: Connect the shielding gas source 106 to form a shielding gas channel. Open the shielding gas source 106 to allow the shielding gas to flow through the shielding gas channel, completely cover the weld laser routing and circulate; connect the outlet of the shielding gas source 106 to the first inlet channel 1-4 through a gas pipeline, and connect the inlet of the shielding gas source 106 to the first outlet channel 1-5. At this time, a complete shielding gas channel is formed in the welding fixture 107. When the back protection block 4 is not set, the shielding gas fills the cavity of the back protection groove 1-2. When the back protection block 4 is set, the shielding gas fills the cavity of the weld groove 4-1.

[0072] Step 2: embed the airbag nozzle 100 into the nozzle groove 1-3, embed the airbag lower wall base material 101 into the limiting groove 1-1, install the first weld cover plate 2 and the support base plate 1, turn on the laser source system 104, and use the movement and control system 103 to move the welding laser gun head 105 to the top of the third weld through hole 2-3, and start welding the first weld (i.e., weld W1, which is circular) to weld the airbag nozzle 100 and the airbag lower wall base material 101 together; the end of the airbag nozzle 100 to be welded faces upward and is flush with the top end surface of the nozzle groove 1-3. When installing the first weld cover plate 2, cover the first weld cover plate 2 on the support base plate 1, and fasten the first weld cover plate 2 to the support base plate 1. The airbag lower wall mother material 101 is embedded between the first limiting boss 2 - 4 and the limiting groove 1 - 1 , and the three are tightly fitted. At the same time, the upper surface of the airbag nozzle 100 is also tightly fitted to the airbag lower wall mother material 101 .

[0073] Step three, disassemble the first weld cover plate 2, stack the airbag upper wall mother material 102 on the airbag lower wall mother material 101 and reinstall the first weld cover plate 2 and the support base plate 1, move the welding laser gun head 105 to above the first weld through hole 2-1, write the program and start welding the second weld (i.e. weld W2, weld W2 is arc-shaped), then move the welding laser gun head 105 to the second weld through hole 2-2, write the program and start welding the third weld (i.e. weld W3, weld W3 is arc-shaped); embed the airbag upper wall mother material 102 into the limiting groove 1-1 and place it on the upper layer of the airbag lower wall mother material 101, then cover the first weld cover plate 2 on the support base plate 1, and fasten the first weld cover plate 2 to the support base plate 1, the second weld and the third weld are the irregular welds at the left and right ends of the thin-walled metal airbag.

[0074] Step 4, disassemble the first weld cover plate 2, replace and install the second weld cover plate 3 on the supporting bottom plate 1, move the welding laser gun head 105 to the top of the fourth weld through hole 3-1, write the program and start welding the fourth weld (i.e. weld W4, weld W2 is a straight line segment), then move the welding laser gun head 105 to the top of the fifth weld through hole 3-2, write the program and start welding the fifth weld (i.e. weld W5, weld W5 is a straight line segment), the welding is completed, the second to fifth welds are cross-closed, and the airbag lower wall base material 101 and the airbag upper wall base material 102 are welded together;

[0075] Step 5: Trim or cut along the periphery of the weld to form a special-shaped thin-walled metal airbag with single-side air intake.

[0076] The geometric features of the five welds W1-W5 described in the embodiment of the present invention are only a typical example of several irregular welds. The geometric form of the welds is not limited to arc or straight line segments, and the present invention is not limited to this single special-shaped thin-walled metal airbag structure.

[0077] By replacing the weld cover plate, constrained welding is performed on the welds at different positions of the thin-walled metal airbag. At the geometric closure of the weld, two laser staggered weldings are used to replace the single laser corner welding, which effectively avoids the ablation and melt-through caused by the heat accumulation at the vertex and realizes the welding formation of irregular welds.

[0078] During the welding process, the welding sequence has a significant impact on the deformation, and thus affects the quality of the weld. Since the airbag nozzle welding position is located between two layers of foil, welding must be performed first. The present invention determines the closed-loop welding sequence of welding between the airbag nozzle and the airbag lower wall parent material 101 → two symmetrical left and right special-shaped welds → two symmetrical front and back straight welds, thereby reducing the unevenness of the thermal stress distribution at the weld position.

[0079] The invention has a simple structure, concise process, reliable and continuous welds, good air tightness, and can realize welding forming of special-shaped thin-walled metal airbags with irregular welds.

[0080] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A welding fixture for special-shaped thin-walled metal airbags, characterized in that: The invention comprises a support base plate (1), a first weld cover plate (2) and a second weld cover plate (3), wherein a limiting groove (1-1) is provided at the top of the support base plate (1), a back protection groove (1-2) and an air nozzle groove (1-3) are provided at the bottom of the limiting groove (1-1), an air bag air nozzle (100) is located in the air nozzle groove (1-3), the back protection groove (1-2) is a closed loop structure and its cross-sectional shape is arranged in accordance with the shape of the weld of the metal air bag, and the support base plate (1) is provided with a limiting groove (1-1), and a back protection groove (1-2) and an air nozzle groove (1-3) are provided at the bottom of the limiting groove (1-1). The support bottom plate (1) is also provided with a first air inlet channel (1-4) and a first air outlet channel (1-5) which are in communication with the back protection groove (1-2); the first weld cover plate (2) is provided with first to third weld pass holes (2-3) which respectively correspond to the welds at the left and right ends of the metal airbag and the circular welds connecting the airbag nozzle (100) and the airbag lower wall base material (101); the second weld cover plate (3) is provided with fourth to fifth weld pass holes (3-2 ), respectively corresponding to the welds at the front and rear ends of the metal airbag, the bottom end of the first weld cover plate (2) is processed with a first limiting boss (2-4) corresponding to the limiting groove (1-1), and the bottom end of the second weld cover plate (3) is processed with a second limiting boss (3-3) corresponding to the limiting groove (1-1), when welding the welds at the left and right ends of the metal airbag and the circular weld connecting the airbag nozzle (100) and the base material (101) of the lower wall of the airbag, The airbag lower wall base material (101) is clamped between the first limiting boss and the limiting groove (1-1) of the supporting bottom plate (1), and the first weld bead cover plate is fixedly connected to the supporting bottom plate (1). When welding the welds at the front and rear ends of the metal airbag, the airbag upper wall base material (102) and the airbag lower wall base material (101) are stacked between the second limiting boss and the limiting groove (1-1) of the supporting bottom plate (1), and the second weld bead cover plate is fixedly connected to the supporting bottom plate (1).

2. A welding fixture for a special-shaped thin-walled metal airbag according to claim 1, characterized in that: A back protection block (4) is conformally embedded in the back protection groove (1-2); the back protection block (4) is a closed-loop structure; a welding groove (4-1) is processed on the upper portion of the back protection block (4); a second air inlet channel (4-2) and a second air outlet channel (4-3) connected to the welding groove (4-1) are processed on the side wall of the back protection block (4); the second air inlet channel (4-2) is arranged opposite to the first air inlet channel (1-4); and the second air outlet channel (4-3) is arranged opposite to the first air outlet channel (1-5).

3. A welding fixture for a special-shaped thin-walled metal airbag according to claim 2, characterized in that: The material of the supporting bottom plate (1), the first weld cover plate (2) and the second weld cover plate (3) are all 06Cr19Ni10, and the material of the back protection block (4) is H61.

4. A welding fixture for a special-shaped thin-walled metal airbag according to claim 2, characterized in that: The width of the weld groove (4-1) is greater than the spot diameter of the laser, and the third weld through hole (2-3) is a circular hole and its diameter is greater than the diameter of the nozzle groove (1-3).

5. The welding fixture for a special-shaped thin-walled metal airbag according to claim 1 is characterized in that: The longitudinal sections of the first weld bead through hole (2-1), the second weld bead through hole (2-2), the fourth weld bead through hole (3-1) and the fifth weld bead through hole (3-2) are all Y-shaped hole structures.

6. A welding fixture for a special-shaped thin-walled metal airbag according to claim 1, characterized in that: The depth of the limiting groove (1-1) and the height of each limiting boss are both 1 mm, and the plane dimensions of the limiting groove (1-1) are the same as those of the airbag lower wall mother material (101) and the airbag upper wall mother material (102).

7. The welding fixture for a special-shaped thin-walled metal airbag according to claim 1, characterized in that: The first air inlet channel (1-4) and the first air outlet channel (1-5) are symmetrically arranged on the front and rear sides of the supporting base plate (1).

8. The welding fixture for a special-shaped thin-walled metal airbag according to claim 1, characterized in that: The cross sections of the limiting groove (1-1) and each limiting boss are both rectangular structures.

9. A welding system, characterized in that: The invention comprises a welding fixture (107) as described in any one of claims 1 to 8, and further comprises a moving and controlling system (103), a laser source system (104), a welding laser gun head (105) and a shielding gas source (106), wherein the welding laser gun head (105) is installed on the moving and controlling system (103) and is connected to the laser source system (104) via an optical fiber, and a first air inlet channel (1-4) and a first air outlet channel (1-5) in the welding fixture (107) are connected to the shielding gas source (106) via gas pipelines.

10. A welding method for a special-shaped thin-walled metal airbag using the welding system of claim 9, comprising the following steps: Step 1: Connect a shielding gas source (106) to form a shielding gas channel, open the shielding gas source (106) to allow shielding gas to flow through the shielding gas channel, completely cover the weld laser routing and circulate; Step 2: embed the airbag nozzle (100) into the nozzle groove (1-3), embed the airbag lower wall base material (101) into the limiting groove (1-1), install the first weld cover plate (2) and the supporting base plate (1), turn on the laser source system (104), use the movement and control system (103) to move the welding laser gun head (105) to the top of the third weld through hole (2-3), and start welding the first weld to overlap and weld the airbag nozzle (100) and the airbag lower wall base material (101) into one; Step 3: remove the first weld cover plate (2), stack the airbag upper wall base material (102) on the airbag lower wall base material (101), and reinstall the first weld cover plate (2) and the supporting base plate (1), move the welding laser gun head (105) to the top of the first weld pass hole (2-1), start welding the second weld, and then move the welding laser gun head (105) to the second weld pass hole (2-2), and start welding the third weld; Step 4: remove the first weld cover plate (2), replace and install the second weld cover plate (3) on the supporting base plate (1), move the welding laser gun head (105) to the top of the fourth weld through hole (3-1), start welding the fourth weld, then move the welding laser gun head (105) to the top of the fifth weld through hole (3-2), start welding the fifth weld, and complete the welding. The second to fifth welds are cross-closed, and the airbag lower wall parent material (101) and the airbag upper wall parent material (102) are overlap-welded into one; Step 5: Trim or cut along the periphery of the weld to form a special-shaped thin-walled metal airbag with single-side air intake.

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