Welding tool and welding method for Dewar transition ring component

Abstract

The invention provides a Dewar transition ring component welding tool and welding method.The Dewar transition ring component welding tool comprises an assembling base, a pressing ring, a first fastener and a centering mechanism, a positioning column of the assembling base is in clearance fit with inner holes of a first transition ring and a second transition ring, and the axial positioning precision of the transition rings is ensured; and the first transition ring and the second transition ring are positioned and centered through the centering mechanism, so that the coaxiality is ensured, and rapid and accurate positioning and assembling of the transition ring parts are achieved, and the first fastener exerts uniform pressing force on the first transition ring and the second transition ring through torque; therefore, close contact of the welding surfaces of the first transition ring and the second transition ring is guaranteed, the welding quality and efficiency are remarkably improved, the welded transition ring component is compact and uniform in welding seam and excellent in sealing performance, the gas leakage rate is greatly reduced, and the use requirement under the high vacuum environment is met.

Description

Technical Field

[0001] This invention relates to the field of infrared detector technology, and specifically to a welding fixture and welding method for a Dewar transition ring component. Background Technology

[0002] The design of the Dewar assemblies for cooled infrared detectors needs to minimize weight while ensuring structural strength. Therefore, base components are typically made of high-strength, low-density titanium alloys, while components related to the welding of optical parts, such as the housing and window mounts, are often made of Kovar alloys, typically plated with dark nickel to improve performance. However, due to the differences in physical properties between titanium alloys and Kovar alloys, a reliable connection cannot be achieved directly through laser welding; current technology uses vacuum brazing with solder.

[0003] However, conventional brazing methods have shortcomings in terms of solder flow control, airtightness stability, and post-weld surface consistency. After the solder melts at high temperature, its wettability and fluidity on the surfaces of titanium alloys and Kovar alloys are different, which can easily lead to uneven welds and unstable airtightness. It can also affect the coaxiality and parallelism of parts, thereby affecting the accuracy of subsequent assembly.

[0004] Currently, the common method for welding is to press the counterweight together. However, this method is not effective in fixing the transition ring components and does not effectively constrain the flow of solder between the transition ring components, which can easily lead to weld gaps and poor quality of the finished product. Summary of the Invention

[0005] In view of the problems existing in the prior art, one of the objectives of the present invention is: In a first aspect, the present invention provides a welding fixture for a Dewar transition ring component, the transition ring component comprising a first transition ring and a second transition ring, including: An assembly base, comprising a base body and a positioning post, wherein the base body is fixedly connected to the positioning post, and a first transition ring and a second transition ring are sleeved on the positioning post, with one end of the first transition ring abutting against the base body; The centering mechanism is used to clamp the first transition ring and the second transition ring so that the first transition ring and the second transition ring are coaxially positioned. A pressure ring is sleeved on the positioning post, and one end of the pressure ring near the second transition ring abuts against the other end of the second transition ring; A first fastener is fitted onto the positioning post. The first fastener is rotatable on the positioning post to abut against the end of the pressure ring away from the second transition ring to press the first transition ring and the second transition ring together so that the first transition ring can be welded to the second transition ring with solder. In one embodiment, the centering mechanism includes a plurality of positioning blocks and at least one second fastener. Each positioning block is respectively disposed on both radial sides of the first transition ring and the second transition ring. The second fastener is used to fasten the two positioning blocks so that the first transition ring and the second transition ring are coaxially positioned.

[0006] In one embodiment, the central cross-section of the positioning block is V-shaped, and the positioning blocks together form a positioning space, with the first transition ring and the second transition ring located in the positioning space.

[0007] In one embodiment, the pressure ring has at least one vent hole.

[0008] In one embodiment, a positioning step is provided on the side of the seat body near the first transition ring, and the first transition ring is sleeved on the positioning step.

[0009] In one embodiment, the second transition ring has an annular boss on the side away from the first transition ring, and the pressure ring has a clearance step on the side close to the second transition ring, with the annular boss inserted into the clearance step.

[0010] In one embodiment, the mounting base further includes a guide post, which is fixed to the end of the positioning post away from the base body, and the diameter of the guide post is smaller than the diameter of the positioning post.

[0011] Secondly, the present invention also provides a welding method for a Dewar transition ring, using the welding fixture for the aforementioned Dewar transition ring component, comprising the following steps: The first transition ring is fitted onto the positioning post, so that one end of the first transition ring abuts against the base; Solder is laid on the side of the first transition ring away from the base; Assemble the second transition ring so that one end of the second transition ring contacts the other end of the first transition ring; The installation centering mechanism clamps the first transition ring and the second transition ring so that the first transition ring and the second transition ring are positioned coaxially. The pressure ring is fitted and the first fastener is tightened to press the first transition ring and the second transition ring together; Remove the centering mechanism and test the coaxiality between the first transition ring and the second transition ring; After the coaxiality of the first transition ring and the second transition ring is qualified, the first transition ring and the second transition ring are brazed under a preset vacuum degree.

[0012] In one embodiment, after the brazing step, the method further includes: Leakage detection was performed on the welded transition ring components.

[0013] In one embodiment, when brazing the first transition ring and the second transition ring under a preset vacuum degree, the solder melts during the brazing process, climbs along the side of the first transition ring closer to the second transition ring, and fills the gap between the wedge-shaped surface of the first transition ring and the mating surface of the second transition ring.

[0014] Compared with the prior art, the advantages of the present invention are that the embodiments of this application provide a welding fixture and welding method for a Dewar transition ring component. The welding fixture for the Dewar transition ring component includes a mounting base, a pressure ring, a first fastener, and a centering mechanism. The positioning pin of the mounting base is fitted with the inner holes of the first and second transition rings with a clearance fit to ensure the axial positioning accuracy of the transition rings. The centering mechanism positions and centers the first and second transition rings, thereby ensuring coaxiality and enabling rapid and accurate positioning and assembly of the transition ring component. The first fastener applies a uniform clamping force to the first and second transition rings with torque, thereby ensuring close contact between the welding surfaces of the first and second transition rings, which significantly improves the welding quality and efficiency. The welded transition ring component has a dense and uniform weld, excellent sealing performance, and greatly reduces the gas leakage rate, meeting the requirements for use in high vacuum environments. Attached Figure Description

[0015] Figure 1 A schematic diagram of the welding fixture for a Dewar transition ring component provided in some embodiments of this application; Figure 2 A first view of a welding fixture for a Dewar transition ring component provided for some embodiments of this application; Figure 3 This is a schematic diagram of the structure of the first transition ring provided in some embodiments of this application; Figure 4 for Figure 3 A magnified view of a section at point A in the middle; Figure 5 This is a schematic diagram of the structure of the second transition ring provided in some embodiments of this application; Figure 6 This is a schematic diagram of the structure of the transition ring component provided in some embodiments of this application; Figure 7 A schematic diagram of the assembly base of a welding fixture for a Dewar transition ring component provided for some embodiments of this application; Figure 8 A schematic diagram of the pressure ring structure of a welding fixture for a Dewar transition ring component provided in some embodiments of this application; Figure 9This is a schematic diagram of the leak detection device in a welding method for a Dewar transition ring component provided in some embodiments of this application.

[0016] Figure label: 1. Assembly base; 11. Base body; 12. Positioning post; 13. Guide post; 14. Positioning step; 2. Pressure ring; 21. Vent hole; 22. Clearance step; 3. First fastener; 4. Centering mechanism; 41. Positioning block; 10. First transition ring; 101. Wedge-shaped surface; 102. Solder step; 103. First connecting part; 20. Second transition ring; 201. Annular boss; 202. Second connecting part; 30. Leak detection device; 301. Leak detection base; 302. Leak detection gland; 303. First sealing ring; 304. Second sealing ring. Detailed Implementation

[0017] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0018] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0019] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0020] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or a joint; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0021] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0022] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0023] The invention will now be further described with reference to the accompanying drawings.

[0024] Firstly, see Figures 1-5This application provides a welding fixture for a Dewar transition ring component, the transition ring component including a first transition ring 10 and a second transition ring 20, and the welding fixture for the Dewar transition ring component including a mounting base 1, a pressure ring 2, a first fastener 3 and a centering mechanism 4. The mounting base 1 includes a base body 11 and a positioning post 12. The base body 11 is fixedly connected to the positioning post 12. A first transition ring 10 and a second transition ring 20 are sleeved on the positioning post 12, and one end of the first transition ring 10 abuts against the base body 11. The centering mechanism 4 is used to clamp the first transition ring 10 and the second transition ring 20 so that the first transition ring 10 and the second transition ring 20 are coaxially positioned. The pressure ring 2 is sleeved on the positioning post 12, and one end of the pressure ring 2 near the second transition ring 20 abuts against the other end of the second transition ring 20. The first fastener 3 is sleeved on the positioning post 12. The first fastener 3 can rotate on the positioning post 12 to abut against the end of the pressure ring 2 away from the second transition ring 20 to press the first transition ring 10 and the second transition ring 20 so that the first transition ring 10 can be welded to the second transition ring 20 by solder. The welding fixture for a Dewar transition ring component provided in this embodiment of the application uses a clearance fit between the positioning post 12 of the assembly base 1 and the inner hole of the first transition ring 10 and the second transition ring 20 to ensure the axial positioning accuracy of the transition ring. The centering mechanism 4 positions and centers the first transition ring 10 and the second transition ring 20 to ensure coaxiality and achieve rapid and accurate positioning and assembly of the transition ring component. The first fastener 3 applies a uniform clamping force to the first transition ring 10 and the second transition ring 20 through torque, thereby ensuring close contact between the welding surfaces of the first transition ring 10 and the second transition ring 20, which significantly improves the welding quality and efficiency. The welded transition ring component has a dense and uniform weld, excellent sealing performance, and greatly reduces the gas leakage rate, meeting the requirements for use in high vacuum environments.

[0025] In this embodiment, transition ring 1 is a rotating body made of titanium alloy, specifically TC4; transition ring 2 is a rotating body made of Kovar alloy, specifically 4J29, and its outer surface is plated with dark nickel.

[0026] In some embodiments, a first connecting portion 103 is provided at one end of the first transition ring 10 near the second transition ring 20, and a second connecting portion 202 is provided at one end of the second transition ring 20 near the first transition ring 10. The height of the first connecting portion 103 is h1, and the height of the second connecting portion 202 is h2. h1 is greater than h2, and the height difference is 0.02mm-0.05mm.

[0027] In this embodiment of the application, the coaxiality requirement is ≤0.02mm.

[0028] like Figure 1 and Figure 2As shown, in some embodiments, the centering mechanism 4 includes a plurality of positioning blocks 41 and at least one second fastener. Each positioning block 41 is respectively disposed on both sides of the first transition ring 10 and the second transition ring 20 in the radial direction. The second fastener is used to fasten the two positioning blocks 41 so that the first transition ring 10 and the second transition ring 20 are coaxially positioned.

[0029] A split-type centering mechanism 4 is formed by two symmetrically arranged positioning blocks 41 and a second fastener, which realizes high-precision coaxial positioning of the transition ring component. Each positioning block 41 clamps the first transition ring 10 and the second transition ring 20 from both radial sides. By locking the first transition ring 10 and the second transition ring 20 with the second fastener, the first transition ring 10 and the second transition ring 20 are automatically aligned, thereby ensuring the coaxiality of the welding surfaces of the first transition ring 10 and the second transition ring 20. This not only simplifies the assembly process but also improves the positioning accuracy. It also makes it easier to disassemble and reuse, and is suitable for welding positioning requirements of transition rings of different sizes. It provides a reliable assembly basis for subsequent vacuum brazing and improves welding quality.

[0030] Specifically, in this embodiment, the centering mechanism 4 includes two positioning blocks 41 and two second fasteners. Each positioning block 41 has a fixing hole at both ends. Each second fastener can pass through the fixing holes of the two opposing positioning blocks 41 in sequence to lock the first transition ring 10 and the second transition ring 20, so that the first transition ring 10 and the second transition ring 20 are automatically centered.

[0031] In other embodiments, the centering mechanism 4 includes two positioning blocks 41 and a second fastener, with one end of the two positioning blocks 41 rotatably connected and the other end of the two positioning blocks 41 fastened by the second fastener.

[0032] like Figure 1 and Figure 2 As shown, in some embodiments, the central cross-section of the positioning block 41 is V-shaped, and the positioning blocks 41 together form a positioning space, with the first transition ring 10 and the second transition ring 20 located in the positioning space.

[0033] By employing V-shaped cross-section positioning blocks 41 and symmetrically arranging two V-shaped positioning blocks 41, which together enclose a positioning space, automatic centering and positioning of the first transition ring 10 and the second transition ring 20 are achieved. Furthermore, the V-shaped structure design allows the first transition ring 10 and the second transition ring 20 to automatically align their centers during assembly. The V-shaped inclined surface also provides guidance, effectively compensating for minor deviations during assembly and improving positioning accuracy, thereby better ensuring the coaxiality of the first transition ring 10 and the second transition ring 20. In addition, the V-shaped cross-section positioning blocks 41 significantly increase the contact area between the positioning blocks 41 and the transition rings, thereby improving positioning stability, ensuring the coaxiality of the first transition ring 10 and the second transition ring 20, and ultimately ensuring welding quality.

[0034] like Figure 1 , Figure 2 and Figure 8 As shown, in some embodiments, the pressure ring 2 has at least one vent hole 21.

[0035] By creating vent holes 21 on the pressure ring 2, effective gas discharge can be achieved during brazing. These vent holes 21 can promptly release the gas trapped in the space during welding heating, preventing defects such as bubbles or incomplete welds caused by gas expansion. Furthermore, the vent holes 21 ensure that the solder fully wets the welding surface during welding, forming a tight and uniform weld. This significantly improves the sealing performance and product quality, effectively solving the problem of welding quality being affected by the inability to discharge gas in traditional welding fixtures, making the welding process more stable and reliable.

[0036] In this embodiment, multiple exhaust holes 21 are evenly spaced along the outer wall of the pressure ring 2.

[0037] like Figure 1 and Figure 7 As shown, in some embodiments, a positioning step 14 is provided on the side of the seat 11 near the first transition ring 10, and the first transition ring 10 is sleeved on the positioning step 14.

[0038] The positioning step 14 and the first transition ring 10 form a sleeve-fit structure, enabling rapid and accurate positioning and reliable fixation of the first transition ring 10. The positioning step 14 provides a precise radial positioning reference for the first transition ring 10, ensuring that the first transition ring 10, the second transition ring 20, and the mounting base 1 remain coaxial. At the same time, the end face of the step forms an axial limit, preventing displacement during welding and significantly improving assembly accuracy and stability. It also simplifies the operation process and allows welding pressure to be evenly transmitted to the welding surface, ensuring high-sealing and high-quality welded products.

[0039] like Figure 1 and Figure 8 As shown, in some embodiments, the second transition ring 20 is provided with an annular boss 201 on the side away from the first transition ring 10, and the pressure ring 2 is provided with a relief step 22 on the side close to the second transition ring 20, with the annular boss 201 inserted into the relief step 22.

[0040] By employing an interlocking structure of the annular boss 201 and the clearance step 22, precise positioning and reliable fixing of the second transition ring 20 and the pressure ring 2 can be achieved. The structure of the annular boss 201 embedded in the clearance step 22 forms a radial limit, effectively preventing relative displacement between the pressure ring 2 and the transition ring during welding, thereby ensuring uniform transmission of welding pressure. In addition, this mating structure also provides a radial positioning reference, keeping the pressure ring 2 and the transition ring precisely aligned and avoiding welding defects caused by assembly deviations.

[0041] In this embodiment, the height of the step 22 is greater than the height of the annular boss 201.

[0042] like Figure 1 and Figure 7 As shown, in some embodiments, the mounting base 1 further includes a guide post 13, which is fixed to the end of the positioning post 12 away from the base body 11, and the diameter of the guide post 13 is smaller than the diameter of the positioning post 12.

[0043] By adding guide posts 13, precise guidance and assembly of the first transition ring 10, the second transition ring 20, the pressure ring 2, and the first fastener 3 can be achieved. In addition, setting the diameter of the guide posts 13 to a stepped structure smaller than that of the positioning posts 12 can further provide guidance for the installation of the first transition ring 10, the second transition ring 20, the pressure ring 2, and the first fastener 3, ensuring that the first transition ring 10, the second transition ring 20, the pressure ring 2, and the first fastener 3 can be pressed down smoothly along the correct path more easily, thereby avoiding skewing during assembly, effectively improving assembly efficiency and accuracy, reducing the risk of component damage due to improper installation, and making the stress on the entire welding fixture more uniform and stable, providing a reliable assembly foundation for obtaining high-quality welded products.

[0044] Secondly, such as Figure 1 , Figure 2 and Figure 6 As shown, one embodiment of this application also provides a welding method for a Dewar transition ring, which uses the welding fixture for the Dewar transition ring component described above, and includes the following steps: The first transition ring 10 is fitted onto the positioning post 12, so that one end of the first transition ring 10 abuts against the base 11; Solder is laid on the side of the first transition ring 10 away from the base 11; Assemble the second transition ring 20 so that one end of the second transition ring 20 contacts the other end of the first transition ring 10; The centering mechanism 4 is installed to clamp the first transition ring 10 and the second transition ring 20 so that the first transition ring 10 and the second transition ring 20 are coaxially positioned. Fit the pressure ring 2 and tighten the first fastener 3 to press the first transition ring 10 and the second transition ring 20 together; Remove the centering mechanism 4 and check the coaxiality between the first transition ring 10 and the second transition ring 20; After the coaxiality of the first transition ring 10 and the second transition ring 20 is qualified, the first transition ring 10 and the second transition ring 20 are brazed under a preset vacuum degree.

[0045] The Dewar transition ring welding method provided in this application embodiment achieves high-precision assembly and reliable welding of the Dewar transition ring components through an optimized welding process. Specialized welding fixtures ensure precise positioning of the first transition ring 10 and the second transition ring 20. Step-by-step assembly, centering clamping, and controlled clamping ensure tight contact and coaxiality of the welding surfaces. Furthermore, brazing is performed in a vacuum environment, effectively avoiding oxidation defects and ensuring the solder fully wets the welding interface, forming a tight and uniform weld. This Dewar transition ring welding method is simple to operate, has good repeatability, significantly improves welding quality and efficiency, and is suitable for welding Dewar transition rings with stringent sealing performance requirements, producing welded products with excellent airtightness and high quality.

[0046] In this embodiment, the vacuum level before heating is required to be ≤5×10⁻⁶. -4 Pa, vacuum degree required during heating ≤5×10 -3 Pa.

[0047] like Figure 1 , Figure 6 and Figure 9 As shown, in some embodiments, after the brazing step, the process further includes: performing a leak detection on the welded transition ring component using a leak detection device 30.

[0048] By adding a leak detection step after the brazing process, reliable verification of welding quality is achieved. A dedicated leak detection device (30) is used to test the sealing of the welded transition ring components, enabling the timely detection and removal of welded parts with micro-leakage, ensuring that the airtightness of each product meets design requirements. This step, as the final quality checkpoint in the welding process, effectively guarantees the long-term reliable use of the transition ring components in a high-vacuum environment, preventing product failure due to welding defects and providing crucial assurance for the performance reliability of the final product.

[0049] In this embodiment, the leakage rate is less than 1×10⁻⁶. -12 Pa·m 3 / S indicates that the condition is acceptable.

[0050] In this embodiment, the torque range of the fastening nut on the first transition ring 10 and the second transition ring 20 is 5 N·m to 8 N·m.

[0051] Specifically, in this embodiment, the leak detection device 30 includes a leak detection base 301 and a leak detection cap 302. The leak detection base 301 has a first annular groove at one end near the second transition ring 20. The second transition ring 20 is fixed to the first annular groove. A first sealing ring 303 is provided between the second transition ring 20 and the first annular groove. The leak detection cover 302 has a second annular groove at one end near the first transition ring 10. The first transition ring 10 is fixed to the second annular groove. A second sealing ring 304 is provided between the first transition ring 10 and the second annular groove.

[0052] By providing a first annular groove and a second annular groove on the leak detection base 301 and the leak detection cover 302 respectively, and forming a double sealing structure with the first sealing ring 303 and the second sealing ring 304, a reliable sealed detection chamber is formed during the testing process. This combination of the annular groove and the sealing ring ensures both the stable fixation of the transition ring component and the complete sealing of the detection interface, preventing external gas interference with the test results. This allows for accurate reflection of the product's sealing performance, providing a reliable testing method for product quality control and effectively guaranteeing the long-term reliability of the transition ring component in high-vacuum application environments. Furthermore, in other embodiments, leak detection can also be performed using a jetting method, a bagging method, or other methods.

[0053] like Figure 1 and Figure 4 As shown, in some embodiments, when brazing the first transition ring 10 and the second transition ring 20 under a preset vacuum degree, the solder melts during the brazing process, climbs along the side of the first transition ring 10 near the second transition ring 20, and fills the gap between the wedge-shaped surface 101 of the first transition ring 10 and the mating surface of the second transition ring 20.

[0054] By setting a wedge-shaped surface 101 in the first transition ring 10, the directional flow and uniform filling of the solder during the brazing process are achieved. The filling gap structure formed by the mating surface of the wedge-shaped surface 101 and the second transition ring 20 guides the molten solder to climb uniformly from bottom to top along the inclined surface, ensuring the integrity and density of the weld. This effectively solves the problem of uneven solder filling that is easy to occur in traditional planar welding, significantly improves the bonding strength and sealing performance of the welding interface, and provides a reliable guarantee for obtaining high-quality welding products.

[0055] In this embodiment, the angle between the contact surface of the wedge-shaped surface 101 and the second transition ring 20 is 3°±1°.

[0056] In this embodiment, a solder step 102 is provided on the side of the first transition ring 10 near the second transition ring 20. The solder step 102 is used to place solder.

[0057] Furthermore, in this embodiment, in order to better assemble the first transition ring 10, the second transition ring 20, and the welding fixture, the outer diameter of the second connecting portion 202 is smaller than the inner diameter of the first connecting portion 103; the outer diameter of the first transition ring 10 and the outer diameter of the second transition ring 20 are equal; the gap between the positioning step 14 and the first transition ring 10 is 0.01mm-0.02mm; the diameter of the positioning post 12 is less than or equal to the outer diameter of the positioning step 14; and the inner diameter of the clearance step 22 of the pressure ring 2 is greater than the outer diameter of the annular boss 201 of the second transition ring 20.

[0058] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A welding fixture for a Dewar transition ring component, the transition ring component comprising a first transition ring and a second transition ring, characterized in that, include: An assembly base, comprising a base body and a positioning post, wherein the base body is fixedly connected to the positioning post, and a first transition ring and a second transition ring are sleeved on the positioning post, with one end of the first transition ring abutting against the base body; The centering mechanism is used to clamp the first transition ring and the second transition ring so that the first transition ring and the second transition ring are coaxially positioned. A pressure ring is sleeved on the positioning post, and one end of the pressure ring near the second transition ring abuts against the other end of the second transition ring; A first fastener, sleeved on the positioning post, is rotatable on the positioning post to abut against the end of the pressure ring away from the second transition ring to press the first transition ring and the second transition ring together, so that the first transition ring can be welded to the second transition ring with solder.

2. The welding fixture for the Dewar transition ring component according to claim 1, characterized in that, The centering mechanism includes a plurality of positioning blocks and at least one second fastener. Each positioning block is respectively disposed on both sides of the first transition ring and the second transition ring in the radial direction. The second fastener is used to fasten the two positioning blocks so that the first transition ring and the second transition ring are coaxially positioned.

3. The welding fixture for the Dewar transition ring component according to claim 2, characterized in that, The central cross-section of the positioning block is V-shaped, and the positioning blocks together form a positioning space, with the first transition ring and the second transition ring located in the positioning space.

4. The welding fixture for the Dewar transition ring component according to claim 1, characterized in that, The pressure ring has at least one vent hole.

5. The welding fixture for the Dewar transition ring component according to claim 1, characterized in that, A positioning step is provided on the side of the seat body near the first transition ring, and the first transition ring is sleeved on the positioning step.

6. The welding fixture for the Dewar transition ring component according to claim 1, characterized in that, The second transition ring has an annular boss on the side away from the first transition ring, and the pressure ring has a clearance step on the side close to the second transition ring, with the annular boss inserted into the clearance step.

7. The welding fixture for the Dewar transition ring component according to claim 1, characterized in that, The mounting base also includes a guide post, which is fixed to the end of the positioning post away from the base body, and the diameter of the guide post is smaller than the diameter of the positioning post.

8. A method for welding a Dewar transition ring, employing the welding fixture for the Dewar transition ring component as described in any one of claims 1-7, characterized in that, Includes the following steps: The first transition ring is fitted onto the positioning post, so that one end of the first transition ring abuts against the base; Solder is laid on the side of the first transition ring away from the base; Assemble the second transition ring so that one end of the second transition ring contacts the other end of the first transition ring; The installation centering mechanism clamps the first transition ring and the second transition ring so that the first transition ring and the second transition ring are positioned coaxially. The pressure ring is fitted and the first fastener is tightened to press the first transition ring and the second transition ring together; Remove the centering mechanism and test the coaxiality between the first transition ring and the second transition ring; After the coaxiality of the first transition ring and the second transition ring is qualified, The first transition ring and the second transition ring are brazed under a preset vacuum level.

9. The welding method according to claim 8, characterized in that, Following the brazing step, the following steps are also included: Leakage detection was performed on the welded transition ring components.

10. The welding method according to claim 8, characterized in that, When brazing the first transition ring and the second transition ring under a preset vacuum, the solder melts during the brazing process, climbs along the side of the first transition ring closer to the second transition ring, and fills the gap between the wedge-shaped surface of the first transition ring and the mating surface of the second transition ring.

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