Sheet metal weld seam air tightness testing device and method

Abstract

The application relates to a sheet metal welding seam air tightness testing device and method, and relates to the sheet metal welding seam detection field.The device comprises a mounting tool, an extrusion assembly, a pressure difference generating assembly and a pressure measuring device.Two groups of sealing elements are arranged on the mounting tool.A sheet metal part can be arranged on the mounting tool and connected with the two groups of sealing elements, and a welding seam on the sheet metal part is located between the two groups of sealing elements.The extrusion assembly can press the sheet metal part tightly on the two groups of sealing elements, so that a closed detection space is formed between the sheet metal part, the two groups of sealing elements and the mounting tool.The pressure difference generating assembly is connected with the detection space, so that a pressure difference between the detection space and the outside world can be generated.Each group of sealing elements is provided with a detection groove on the opposite side of the sheet metal part, the detection groove can surround the sheet metal part to form a closed space separated from the detection space, and the pressure measuring device is connected with the detection groove.The application reduces the influence of air leakage of the sealing element on the welding seam qualification of the sheet metal part, and improves the accuracy of the sheet metal part welding seam air tightness test.

Description

Technical Field

[0001] This application relates to the field of sheet metal weld inspection, and in particular to a sheet metal weld airtightness testing device and method. Background Technology

[0002] As the weakest point in the connection of sheet metal components, welds formed by sheet metal welding are prone to hidden defects such as porosity, slag inclusions, incomplete penetration, and microcracks due to improper process control during welding. These defects will form tiny gaps or channels at the weld. If the airtightness is not tested, these defects will directly affect the performance and structural reliability of the sheet metal parts. Therefore, the core of conducting airtightness testing on sheet metal welds is to verify the sealing integrity of the weld, promptly detect and eliminate potential welding defects, and fundamentally ensure the functionality, structural safety, and service life of sheet metal components.

[0003] Existing methods for sheet metal airtightness testing, such as the patent document with publication number CN117571229A, disclose a weld seam testing device for the electrode frame-plate or nipple plate of an alkaline water hydrogen production electrolyzer. In this patent, the welded workpiece is placed on a rotating platform, with the weld seam located between two sealing rings. A clamping mechanism presses the workpiece firmly onto the rotating platform via a clamping plate. An air pump extracts air from the sealing groove on the rotating platform until the pressure gauge indicates that the weld seam has reached a vacuum state, which is maintained for a certain period. The airtightness of the weld seam is judged based on whether there is a pressure difference change during the pressure holding time. However, due to environmental factors and repeated use, the sealing rings may age and lose elasticity, making them prone to leakage during the pressure holding process. This affects the airtightness testing of the weld seam and reduces its accuracy. Summary of the Invention

[0004] To address the issue of leaks in sealing rings that reduce the accuracy of weld airtightness testing, this application provides a sheet metal weld airtightness testing device and method.

[0005] The sheet metal weld air tightness testing device and method provided in this application adopts the following technical solution: A sheet metal weld airtightness testing device includes an installation fixture, a pressing assembly, a differential pressure generating assembly, and a pressure measuring device. The installation fixture is provided with two sets of sealing elements. A sheet metal part can be placed on the installation fixture and connected to the two sets of sealing elements, with the weld seam on the sheet metal part located between the two sets of sealing elements. The pressing assembly can press the sheet metal part tightly onto the two sets of sealing elements, so that a closed testing space is formed between the sheet metal part, the two sets of sealing elements, and the installation fixture. The differential pressure generating assembly is connected to the testing space to generate a pressure difference between the testing space and the outside. Each set of sealing elements has a testing groove on the opposite side of the sheet metal part. The testing groove and the sheet metal part can form a closed space that is separated from the testing space. The pressure measuring device is connected to the testing groove.

[0006] By adopting the above technical solution, the sheet metal part is first installed on the mounting fixture. The weld seam on the sheet metal part is located between two sets of seals. Then, the sheet metal part is pressed tightly onto the two sets of seals by the extrusion assembly, so that the sheet metal part, the two sets of seals, and the mounting fixture form a test space. The test groove and the sheet metal part form a closed space. Then, the pressure difference generating assembly acts on the test space to generate a pressure difference between the test space and the outside. Pressure is maintained, and the pressure in the test space at the beginning of the pressure maintenance is recorded, as well as the pressure in the test groove is recorded by the pressure measuring device. After the pressure maintenance ends, the pressure in the test space and the pressure in the test groove are recorded. Based on the pressure difference in the test space before and after the pressure maintenance, and combined with the pressure difference in the test groove before and after the pressure maintenance, the weld seam of the sheet metal part is comprehensively judged as qualified. By measuring the pressure difference in the test groove before and after the pressure maintenance, the leakage between the seals and the sheet metal part is included in the parameters for judging the weld seam of the sheet metal part, thereby reducing the impact of air leakage of the seals on the weld seam of the sheet metal part and improving the accuracy of the airtightness test of the sheet metal part weld seam.

[0007] Preferably, the sealing element includes an inner ring and an outer ring, with the detection groove formed between the inner ring and the outer ring. The inner ring can form a sealing relationship with the sheet metal part and the mounting fixture, and the outer ring can form a sealing relationship with the sheet metal part and the mounting fixture.

[0008] By adopting the above technical solution, the inner and outer rings of the sealing ring can form a sealing relationship with the sheet metal parts and the mounting fixtures respectively, effectively separating the testing space and the testing groove, ensuring that the testing groove can form an independent closed space, facilitating accurate measurement of the pressure in the testing groove, and further improving the accuracy of the airtightness test of the sheet metal weld.

[0009] Preferably, the detection groove is provided with a support member, and the support member has a connecting channel. The connecting channel extends from the side of the support member facing the mounting fixture to the side facing the sheet metal part. The two sides of the support member are in contact with the inner ring and the outer ring, respectively. The support member can contact the sheet metal part through the opening of the detection groove. The mounting fixture is provided with an elastic element, which is connected to the support member so as to drive the support member to reset.

[0010] By adopting the above technical solution, when the sheet metal part deforms under the pressure of the inner and outer rings, the supporting component, supported by the elastic element, always maintains contact with the sheet metal part. Moreover, the detection groove is connected to the gap between the inner ring and the sheet metal part through the connecting channel, preventing the opening of the detection groove from being blocked when the inner and outer rings deform. This breaks the gap between the detection groove and the inner ring and the sheet metal part, allowing the pressure change in the detection groove to accurately reflect the sealing between the inner ring and the sheet metal part, thereby improving the accuracy of the sheet metal part weld airtightness test.

[0011] Preferably, the detection groove is provided with an inner support ring and an outer support ring, and a sliding channel is formed between the inner support ring and the outer support ring. The support member is inserted into the sliding channel and can slide along the sliding channel.

[0012] By adopting the above technical solution, the sliding channel formed by the inner and outer support rings is utilized to prevent the inner and outer rings from blocking the movement path of the support component during compression deformation, thereby improving the stability of the support component's movement.

[0013] Preferably, the installation fixture includes a test base and a support plate. The test base corresponds one-to-one with the weld seams on the sheet metal part. The shape of the test base is adapted to the weld seams of the sheet metal part. The test base is disposed on the support plate. The test base can form the testing space with the sheet metal part and the two sets of seals.

[0014] By adopting the above technical solution, the test base corresponds one-to-one with the weld seams on the sheet metal parts and the shape is adapted to fit the weld seams of the sheet metal parts better. It forms a test space with the sheet metal parts and the two sets of seals, improving the sealing of the test space and making the test process more accurate and reliable. At the same time, the support plate provides support for the test base, which facilitates the layout and operation of the overall structure.

[0015] Preferably, it also includes a cover and a base plate. The mounting fixture is disposed on the base plate, and the cover is disposed on the base plate and covers the mounting fixture, providing space for the airtightness test of the sheet metal parts.

[0016] By adopting the above technical solution, the mounting fixture is placed on the base plate and covered with a cover, which can provide a relatively closed space for the airtightness test of sheet metal parts, reduce the interference of external environmental factors on the test results, and make the test process more stable and reliable.

[0017] Preferably, the cover has a side opening, the bottom plate has a guide rail, and the tray is slidably connected to the guide rail, so that the tray can slide out of the cover through the side opening.

[0018] By adopting the above technical solution, it is convenient for operators to slide the pallet out of the cover to install and disassemble sheet metal parts, thereby improving the convenience and work efficiency of the testing device.

[0019] Preferably, the extrusion assembly corresponds one-to-one with the test base. Each extrusion assembly includes a linear drive structure and a pressure plate. The linear drive structure is disposed on the cover, and the pressure plate is disposed on the output end of the linear drive structure and opposite to the test base. The linear drive structure can drive the pressure plate to move toward the test base.

[0020] By adopting the above technical solution, the linear drive structure drives the pressure plate to move towards the test base, which can accurately press the sheet metal parts onto the two sets of seals, so that the sheet metal parts, seals and installation fixtures reliably form the test space, ensuring the airtightness of the test space, providing a stable environment for subsequent differential pressure testing, and thus ensuring the smooth progress of the sheet metal weld airtightness test.

[0021] Preferably, the differential pressure generating component includes a gas source and a gas pipe. One end of the gas pipe is inserted into the test base and communicates with the detection space, while the other end is connected to the gas source, which can inject gas into the detection space.

[0022] By adopting the above technical solution, gas is injected into the detection space through the gas pipe from the gas source, which can effectively create a pressure difference between the detection space and the outside world. This provides a basis for accurately judging the airtightness of the sheet metal weld and ensures the stability and reliability of the pressure difference.

[0023] A method for testing the airtightness of sheet metal welds includes the following steps: S1. Install the sheet metal part on an installation fixture, with the weld on the sheet metal part located between two sets of seals; S2. A pressing assembly presses the sheet metal part tightly onto the two sets of seals, forming a test space between the sheet metal part, the two sets of seals, and the installation fixture, and a test groove forms a closed space with the sheet metal part; S3. A pressure differential generating assembly acts on the test space, creating a pressure difference between the test space and the outside; S4. Maintain pressure, recording the pressure P1 of the test space at the initial pressure holding and the pressure P2 of the test groove through a pressure measuring device; S5. After the pressure holding is completed, record the pressure P3 in the test space and the pressure P4 in the test groove; S6. When setting weld seam standards, the maximum allowable difference between the pressure in the test space and the external pressure is ΔP, where α is a pressure correction coefficient; If |P1-P3|≤ΔP, then the sheet metal weld seam is qualified; If |P1-P3|>ΔP and |P2-P4|≤αΔP, then the weld of the sheet metal part is qualified; if |P1-P3|>ΔP and |P2-P4|>αΔP, then the weld of the sheet metal part is unqualified.

[0024] By adopting the above technical solution, the pressure difference in the detection space before and after pressure holding, combined with the pressure difference in the detection tank before and after pressure holding, is used to comprehensively judge whether the weld of the sheet metal part is qualified. This multi-parameter comprehensive judgment method can more accurately and comprehensively evaluate the weld sealing performance, reduce misjudgments caused by errors in judging a single parameter, and improve the reliability of the sheet metal part weld airtightness test results.

[0025] In summary, this application includes at least one of the following beneficial technical effects: 1. Based on the pressure difference in the test space before and after pressure holding, and combined with the pressure difference in the test tank before and after pressure holding, the weld of the sheet metal part is judged to be qualified. By measuring the pressure difference in the test tank before and after pressure holding, the leakage between the seal and the sheet metal part is included in the parameter for judging the weld qualification of the sheet metal part, thereby reducing the impact of air leakage of the seal on the weld qualification of the sheet metal part and improving the accuracy of the air tightness test of the sheet metal weld. 2. Under the support of the elastic element, the supporting component always maintains contact with the sheet metal part and is connected to the gap between the inner ring and the sheet metal part through the connecting channel. This prevents the opening of the detection groove from being blocked when the inner and outer rings deform, so that the pressure change in the detection groove can accurately reflect the sealing between the inner ring and the sheet metal part, thereby improving the accuracy of the sheet metal weld airtightness test. 3. The sheet metal parts are squeezed by a pressure plate driven by a linear drive structure, and the pallet can slide out from the side opening of the cover, which improves the automation and convenience of the sheet metal weld airtightness test. Attached Figure Description

[0026] Figure 1This is a schematic diagram of the structure of a sheet metal weld air tightness testing device according to an embodiment of this application.

[0027] Figure 2 This is a structural diagram used to illustrate the extrusion assembly.

[0028] Figure 3 It is an exploded view used to show the fit between sheet metal parts and test base.

[0029] Figure 4 It is an exploded view used to show the interaction between a set of welds on a sheet metal part and a single test base.

[0030] Figure 5 It is a display Figure 4 Top view of the structure.

[0031] Figure 6 It is along Figure 5 A cross-sectional view along line AA in the middle.

[0032] Figure 7 yes Figure 6 Enlarged view of section B in the middle.

[0033] Figure 8 It is along Figure 5 A cross-sectional view of the CC line.

[0034] Explanation of reference numerals in the attached drawings: 1. Sheet metal part; 11. Weld; 21. Cover; 211. Side opening; 22. Base plate; 221. Guide rail; 3. Mounting fixture; 31. Support plate; 32. Test base; 4. Extrusion assembly; 41. Linear drive structure; 42. Pressure plate; 5. Differential pressure generating assembly; 51. Air source; 52. Air pipe; 53. Gas passage; 6. Pressure measuring device; 61. Pressure sensor; 7. Seal; 71. Inner ring; 72. Outer ring; 73. Detection groove; 74. Measurement channel; 751. Support inner ring; 752. Support outer ring; 753. Sliding channel; 76. Support component; 761. Connecting channel; 77. Elastic element; 771. Telescopic spring; 8. Detection space. Detailed Implementation

[0035] The following will be combined with the appendix Figures 1-8 The technical solutions in the embodiments of the present invention are further described in detail below. The described embodiments are only possible technical implementations of the present invention, but are not limited thereto. Those skilled in the art can certainly combine the embodiments of the present invention to obtain other embodiments without creative effort, which are also within the protection scope of the present invention.

[0036] This application mainly uses the setting of detection groove 73 combined with pressure difference to judge the air tightness of weld 11, which achieves the effect of reducing the impact of air leakage of sealing component 7 and improving the accuracy of detection. The following is a further detailed description of this application. Example 1

[0037] This application discloses a sheet metal weld airtightness testing device.

[0038] Reference Figure 1 , Figure 2 A sheet metal weld airtightness testing device includes a housing 21, a base plate 22, a mounting fixture 3, an extrusion assembly 4, a differential pressure generating assembly 5, and a pressure measuring device 6. In this embodiment, the weld seam 11 on the sheet metal part 1 has a rectangular trajectory, formed by welding a rectangular plate onto the sheet metal part 1, and there are two weld seams 11. The housing 21 is mounted on the base plate 22, and a weld seam 11 testing environment is formed inside the housing 21. A side opening 211 is provided on one side of the housing 21, and two parallel guide rails 221 are provided on the base plate 22, with each guide rail 221 extending from the side opening 211.

[0039] Reference Figure 2 , Figure 3 In this embodiment, the installation fixture 3 includes a tray 31 and a test base 32. There are two test bases 32, both of which are fixedly installed on the tray 31. Each test base 32 is provided with two sets of sealing elements 7. Each test base 32 corresponds to a weld 11 on the sheet metal part 1. The test base 32 is adapted to the surrounding structure of the weld 11 on the sheet metal part 1. The tray 31 is slidably connected to the corresponding guide rail 221 through a slider. The tray 31 can slide out of the cover 21 through the side opening 211, and then the sheet metal part 1 is installed on the test base 32 on the tray 31. This makes it convenient for the operator to slide the tray 31 out of the cover 21 to install and remove the sheet metal part 1, improving the convenience and work efficiency of the testing device.

[0040] There are two extrusion components 4, with one extrusion component 4 corresponding to each test base 32. In this embodiment, the extrusion component 4 includes a linear drive structure 41 and a pressure plate 42. The linear drive structure 41 includes, but is not limited to, one of a linear cylinder, a linear hydraulic cylinder, and a linear motor. In this embodiment, a linear cylinder is preferred. The cylinder body of the linear drive structure 41 is fixedly connected to the cover 21. The piston rod of the linear drive structure 41 is set towards the test base 32. The pressure plate 42 is fixedly set on the piston rod of the linear drive structure 41. The linear drive structure 41 drives the pressure plate 42 to move down and press down on the sheet metal part 1, providing extrusion force for the sealing relationship between the sheet metal part 1 and the sealing member 7.

[0041] Reference Figure 4 , Figure 5 and Figure 6In this embodiment, a set of welds 11 on sheet metal part 1 and a test base 32 on tray 31 are used as examples. In order to adapt to sheet metal part 1, test base 32 is set in a stepped shape. Two sets of sealing elements 7 are respectively set on test base 32. The two sets of sealing elements 7 are rectangular frame structures with the same structure but different sizes. One set of sealing elements 7 is set on the top of test base 32, and the other set of sealing elements 7 is set on the step in the middle of test base 32. When sheet metal part 1 is placed on test base 32, the set of welds 11 on sheet metal part 1 is located between the two sets of sealing elements 7. The sheet metal part 1 is pressed down by linear drive structure 41, forming a closed detection space 8 between sheet metal part 1, the two sets of sealing elements 7 and test base 32. The differential pressure generating component 5 can inflate the detection space 8, so that the pressure in the detection space 8 is greater than the external pressure.

[0042] Reference Figure 6 , Figure 7 In this embodiment, a set of sealing components 7 is used as an example. The sealing component 7 includes an inner ring 71 and an outer ring 72. Both the inner ring 71 and the outer ring 72 are made of silicone. The inner ring 71 and the outer ring 72 are inserted into the test fixture and fixed by adhesive. On the one hand, this improves the sealing performance between the inner ring 71, the outer ring 72 and the test fixture. On the other hand, it can fix the inner ring 71 and the outer ring 72 and prevent them from moving around. A detection groove 73 is formed between the inner ring 71 and the outer ring 72. A measurement channel 74 is provided on the side wall of the test base 32. The measurement channel 74 corresponds one-to-one with the detection groove 73. The measurement channel 74 passes through the detection groove 73 and is connected to the detection groove 73. In this embodiment, the pressure measuring device 6 is a pressure sensor 61. The pressure sensor 61 corresponds one-to-one with the measurement channel 74. The pressure sensor 61 is inserted into the measurement channel 74. Since the measurement channel 74 is connected to the detection groove 73, the pressure value measured by the pressure sensor 61 is the pressure value in the detection groove 73.

[0043] The detection groove 73 is provided with an inner support ring 751 and an outer support ring 752. The inner support ring 751 and the outer support ring 752 have the same structure as the inner ring 71 or the outer ring 72, and are all made of metal. The inner support ring 751 and the outer support ring 752 are fixedly connected to the test base 32. The inner support ring 751 is set close to the inner ring 71, and the outer support ring 752 is set close to the outer ring 72. The depth of the detection groove 73 is greater than the height of the inner support ring 751 and the outer support ring 752 along this direction, providing a range for the extrusion deformation of the inner ring 71 and the outer ring 72. A sliding channel 753 is formed between the inner ring 751 and the outer ring 752. A hollow frame-shaped support member 76 is provided in the detection groove 73. One end of the support member 76 is inserted into the sliding channel 753, and the other end is flush with the top surface of the inner ring 71. A connecting channel 761 is provided on the support member 76. The connecting channel 761 extends from the side of the support member 76 facing the mounting fixture 3 to the side facing the sheet metal part 1.

[0044] When the pressure plate 42 presses the sheet metal part 1, the sheet metal part 1 deforms the inner ring 71 and the outer ring 72. The inner ring 71 and the outer ring 72 deform back into the detection groove 73, which will block the opening of the detection groove 73. To address this, a support member 76 is provided so that during the deformation of the sheet metal part 1 by pressing the inner ring 71 and the outer ring 72, the support member 76, supported by the telescopic spring 771, always maintains contact with the sheet metal part 1. The detection groove 73 is kept connected to the gap between the inner ring 71 and the sheet metal part 1 through the connecting channel 761, preventing the inner ring 71 and the outer ring 72 from blocking the opening of the detection groove 73 when they deform. This breaks the gap between the detection groove 73 and the inner ring 71 and the sheet metal part 1, so that the pressure change in the detection groove 73 can accurately reflect the sealing between the inner ring 71 and the sheet metal part 1, thereby improving the accuracy of the airtightness test of the weld 11 of the sheet metal part 1.

[0045] When the inner ring 71 and the outer ring 72 deform, the parts of the inner ring 71 and the outer ring 72 near the bottom will deform toward the detection groove 73, affecting the sliding of the support member 76. To address this, a support inner ring 751 and a support outer ring 752 are provided. The sliding channel 753 formed by the support inner ring 751 and the support outer ring 752 is used to prevent the inner ring 71 and the outer ring 72 from blocking the movement path of the support member 76 when they are compressed and deformed, thereby improving the stability of the movement of the support member 76.

[0046] The detection groove 73 is provided with multiple elastic elements 77. In this embodiment, the elastic element 77 is a telescopic spring 771. The telescopic spring 771 is disposed between the support member 76 and the test base 32. One end of the telescopic spring 771 is fixedly connected to the support member 76, and the other end is fixedly connected to the test base 32. When the sheet metal part 1 presses down on the inner ring 71 and the outer ring 72, the telescopic spring 771 is compressed by the support member 76 and contracts, so that the support member 76 can move with the deformation of the inner ring 71 and the outer ring 72. When the pressure plate 42 releases the pressure on the sheet metal part 1, the inner ring 71 and the outer ring 72 return to their original state. At this time, the telescopic spring 771 pushes the support member 76 to reset.

[0047] Reference Figure 1 , Figure 8 In this embodiment, the differential pressure generating component 5 includes a gas source 51 and a gas pipe 52. The gas source 51 can be a structure composed of a gas pump and a gas tank. Each test base 32 has a gas channel 53 at its bottom that communicates with the test space 8. The gas source 51 and each gas channel 53 are connected through a gas pipe 52. The gas pipe 52 is a flexible pipe, which allows the gas source 51 to inject gas into the test space 8. At the same time, a valve and a pressure gauge are installed on the gas pipe 52. The pressure gauge detects the pressure of the gas in the test space 8. The pressure holding process is carried out by closing the valve.

[0048] The implementation principle of Embodiment 1 of this application is as follows: First, the sheet metal part 1 is installed on the test base 32. The weld 11 on the sheet metal part 1 is located between the two sets of seals 7. Then, the sheet metal part 1 is pressed onto the two sets of seals 7 by the linear drive structure 41 and the pressure plate 42, so that the sheet metal part 1, the two sets of seals 7 and the mounting fixture 3 form a test space 8. The test groove 73 and the sheet metal part 1 form a closed space. Then, air is injected into the test space 8 through the air source 51, so that the test space 8 and the outside world are generated. Pressure is maintained, and the pressure of the test space 8 at the beginning of the pressure maintenance and the pressure difference are recorded. The measuring device 6 records the pressure in the test groove 73. After the pressure holding is completed, the pressure in the test space 8 and the pressure in the test groove 73 are recorded. Based on the pressure difference in the test space 8 before and after the pressure holding, and combined with the pressure difference in the test groove 73 before and after the pressure holding, the weld 11 of the sheet metal part 1 is judged to be qualified. By measuring the pressure difference in the test groove 73 before and after the pressure holding, the leakage between the seal 7 and the sheet metal part 1 is included in the parameters for judging the qualification of the weld 11 of the sheet metal part 1, thereby reducing the impact of the leakage of the seal 7 on the qualification of the weld 11 of the sheet metal part 1 and improving the accuracy of the air tightness test of the weld 11 of the sheet metal part 1. Example 2

[0049] This embodiment 2 discloses a testing method using the sheet metal weld air tightness testing device of embodiment 1, comprising the following steps: S1. Install the sheet metal part 1 on the installation tooling 3. The weld seam 11 on the sheet metal part 1 is located between two groups of seals 7. During installation, ensure that the positions of the sheet metal part 1 and the installation tooling 3 are accurate, and the weld seam 11 is in a suitable position between the two groups of seals 7. A positioning tool can be used to assist in the installation.

[0050] S2. The extrusion assembly 4 presses the sheet metal part 1 against the two groups of seals 7, so that a detection space 8 is formed between the sheet metal part 1, the two groups of seals 7 and the installation tooling 3, and a closed space is formed between the detection groove 73 and the sheet metal part 1. Start the linear drive structure 41 of the extrusion assembly 4 to make the pressure plate 42 move towards the test base 32, and gradually press the sheet metal part 1. During this process, pay attention to observing the pressing force to avoid damaging the sheet metal part 1 due to excessive extrusion.

[0051] S3. The differential pressure generating assembly 5 acts on the detection space 8 to generate a pressure difference between the detection space 8 and the outside. Open the air source 51 and inject gas into the detection space 8 through the air pipe 52 to increase the pressure of the detection space 8 so that it is higher than the outside pressure.

[0052] S4. When the pressure rises to the required value, close the valve on the air pipe 52 and enter the pressure holding process. At the beginning of the pressure holding process, record the pressure P1 of the detection space 8 at the initial stage of pressure holding through the pressure gauge and record the pressure P2 of the detection groove 73 through the pressure sensor 61.

[0053] S5. After the pressure holding ends, record the pressure P3 in the detection space 8 through the pressure gauge and the pressure P4 in the detection groove 73 detected by the pressure sensor 61.

[0054] S6. When setting that the weld seam 11 is qualified, set the maximum allowable difference ΔP between the pressure in the detection space 8 and the outside pressure. ΔP can be considered as specified or measured manually. At the same time, set the pressure correction coefficient α, which is a value specified according to the volume ratio of the detection groove 73 to the detection space 8 and the difference between the inner ring 71 and the outer ring 72. According to the data obtained in S4 and S5, judge whether the weld seam 11 is qualified as follows: If |P1 - P3| ≤ ΔP, the weld seam 11 of the sheet metal part 1 is qualified; If |P1 - P3| > ΔP and |P2 - P4| ≤ αΔP, the weld seam 11 of the sheet metal part 1 is qualified; If |P1 - P3| > ΔP and |P2 - P4| > αΔP, the weld seam 11 of the sheet metal part 1 is unqualified.

[0055] For example: P1=200kPa, P2=101kPa, P3=195kPa, P4=110kPa, ΔP=3kPa, α=2, then |P1 - P3|=5kPa>ΔP, |P2 - P4|=9kPa<αΔP=10kPa, then the weld 11 of the sheet metal part 1 is qualified.

[0056] The implementation principle of Example 2: This test method combines the structural characteristics of the sheet metal weld airtightness testing device. By measuring and comparing the pressure difference between the detection space 8 and the detection groove 73, it comprehensively considers the leakage between the seal 7 and the sheet metal part 1, and can accurately determine the airtightness of the weld 11 of the sheet metal part 1. Compared with traditional methods that only focus on the pressure difference of the detection space 8, this method is more scientific and accurate, effectively avoiding misjudgments caused by air leakage of the seal 7, improving the reliability and effectiveness of the airtightness test of the weld 11 of the sheet metal part 1, and ensuring the quality and performance of the sheet metal components.

[0057] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A sheet metal weld airtightness testing device, characterized in that: The assembly includes an installation fixture (3), an extrusion assembly (4), a differential pressure generating assembly (5), and a pressure measuring device (6). The installation fixture (3) is provided with two sets of seals (7). The sheet metal part (1) can be placed on the installation fixture (3) and connected to the two sets of seals (7). The weld (11) on the sheet metal part (1) is located between the two sets of seals (7). The extrusion assembly (4) can press the sheet metal part (1) onto the two sets of seals (7), so that a closed detection space (8) is formed between the sheet metal part (1), the two sets of seals (7), and the installation fixture (3). The differential pressure generating assembly (5) is connected to the detection space (8) so that a pressure difference is generated between the detection space (8) and the outside. Each of the sealing elements (7) and the sheet metal parts (1) is provided with a detection groove (73). The detection groove (73) can form a closed space with the sheet metal parts (1) that is separated from the detection space (8). The pressure measuring device (6) is connected to the detection groove (73).

2. The sheet metal weld airtightness testing device according to claim 1, characterized in that: The sealing element (7) includes an inner ring (71) and an outer ring (72), and the detection groove (73) is formed between the inner ring (71) and the outer ring (72). The inner ring (71) can form a sealing relationship with the sheet metal part (1) and the mounting fixture (3), and the outer ring (72) can form a sealing relationship with the sheet metal part (1) and the mounting fixture (3).

3. The sheet metal weld airtightness testing device according to claim 2, characterized in that: The detection groove (73) is provided with a support member (76), and the support member (76) is provided with a connecting channel (761). The connecting channel (761) extends from the side of the support member (76) facing the mounting fixture (3) to the side facing the sheet metal part (1). The two sides of the support member (76) are in contact with the inner ring (71) and the outer ring (72) respectively. The support member (76) can contact the sheet metal part (1) through the opening of the detection groove (73). The mounting fixture (3) is provided with an elastic member (77), which is connected to the support member (76) so as to drive the support member (76) to reset.

4. The sheet metal weld airtightness testing device according to claim 3, characterized in that: The detection groove (73) is provided with a supporting inner ring (751) and a supporting outer ring (752), and a sliding channel (753) is formed between the supporting inner ring (751) and the supporting outer ring (752). The supporting member (76) is inserted into the sliding channel (753) and can slide along the sliding channel (753).

5. The sheet metal weld airtightness testing device according to claim 1, characterized in that: The installation fixture (3) includes a test base (32) and a support plate (31). The test base (32) corresponds one-to-one with the weld (11) on the sheet metal part (1). The shape of the test base (32) is adapted to the weld (11) of the sheet metal part (1). The test base (32) is set on the support plate (31). The test base (32) can form the detection space (8) with the sheet metal part (1) and the two sets of seals (7).

6. The sheet metal weld airtightness testing device according to claim 5, characterized in that: It also includes a cover (21) and a base plate (22). The mounting fixture (3) is set on the base plate (22), and the cover (21) is set on the base plate (22) and covers the mounting fixture (3) to provide space for the airtightness test of the sheet metal part (1).

7. The sheet metal weld airtightness testing device according to claim 6, characterized in that: The cover (21) has a side opening (211), and the bottom plate (22) has a guide rail (221). The support plate (31) is slidably connected to the guide rail (221), so that the support plate (31) can slide out of the cover (21) through the side opening (211).

8. The sheet metal weld airtightness testing device according to claim 6, characterized in that: The extrusion assembly (4) corresponds one-to-one with the test base (32). Each extrusion assembly (4) includes a linear drive structure (41) and a pressure plate (42). The linear drive structure (41) is mounted on the cover (21), and the pressure plate (42) is mounted on the output end of the linear drive structure (41) and is opposite to the test base (32). The linear drive structure (41) can drive the pressure plate (42) to move toward the test base (32).

9. The sheet metal weld airtightness testing device according to claim 5, characterized in that: The differential pressure generating component (5) includes a gas source (51) and a gas pipe (52). One end of the gas pipe (52) is inserted into the test base (32) and communicates with the detection space (8). The other end is connected to the gas source (51). The gas source (51) can inject gas into the detection space (8).

10. A testing method using the sheet metal weld air tightness testing device according to any one of claims 1-9, characterized in that: Includes the following steps: S1. Install the sheet metal part (1) on the mounting fixture (3), with the weld (11) on the sheet metal part (1) located between the two sets of seals (7); S2, the extrusion assembly (4) presses the sheet metal part (1) onto the two sets of seals (7), so that the sheet metal part (1), the two sets of seals (7), and the installation fixture (3) form a detection space (8), and the detection groove (73) and the sheet metal part (1) form a closed space; S3, The differential pressure generating component (5) acts on the detection space (8) to generate a pressure difference between the detection space (8) and the outside world; S4. Hold pressure and record the pressure P1 of the detection space (8) at the beginning of the pressure holding and the pressure P2 of the detection groove (73) through the pressure measuring device (6); S5. After the pressure holding is completed, record the pressure P3 in the detection space (8) and the pressure P4 in the detection groove (73); S6. When the weld (11) is qualified, the maximum allowable difference between the pressure in the detection space (8) and the external pressure is ΔP, and α is the pressure correction coefficient. If |P1-P3|≤ΔP, then the weld (11) of the sheet metal part (1) is qualified; If |P1-P3|>ΔP and |P2-P4|≤αΔP, then the weld (11) of the sheet metal part (1) is qualified; If |P1-P3|>ΔP and |P2-P4|>αΔP, then the weld (11) of the sheet metal part (1) is unqualified.

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