Cold extrusion method for slow wave assembly of traveling wave tube

Abstract

The application provides a slow wave assembly cold extrusion method for a traveling wave tube, and relates to the technical field of vacuum electron devices. First, based on a preset rebound amount, the wound helix and the core rod are tightly bonded by using an adhesive, the clamping rod and the helix with the core rod are sequentially placed into multiple sets of clamping assemblies, guide dies and limiting dies are assembled at both ends, and screws are used to lock the multiple sets of clamping assemblies, the clamping rod and the helix with the core rod; then, the positioned clamping rod and the helix are pushed into a composite tube shell, the multiple sets of clamping assemblies are sequentially removed, and after assembly, the guide dies and the limiting dies are removed. The assembled assembly is immersed in an organic solvent such as acetone to remove the glue, the helix, the clamping rod and the composite tube shell are automatically clamped through the rebound of the outer diameter of the helix, and finally, the core rod is removed, and the cold extrusion of the slow wave assembly is completed.

Description

Technical Field

[0001] This invention relates to the field of vacuum electronic device technology, specifically to the field of traveling wave tube slow wave assembly fabrication technology, and more specifically to a cold extrusion method for a traveling wave tube slow wave assembly. Background Technology

[0002] Traveling wave tubes (TWTs) are key components of satellites and belong to the category of vacuum electronic devices. The slow-wave module of a TWT slows down the phase velocity of electromagnetic waves, reducing it to a level essentially the same as the velocity of electrons. This allows for a full exchange of energy between electrons and electromagnetic waves, achieving signal amplification. This process determines the main specifications and secondary characteristics of the TWT. Therefore, the yield and consistency of the extruded slow-wave module are crucial to the overall consistency of the TWT.

[0003] In slow-wave components, the helix is ​​a high-precision, slender part similar to a spring, typically made of tungsten strip. Traditionally, it is prepared by high-temperature setting (e.g., 1300℃, 30min) and then by melting the core rod to ensure that the pitch and diameter of the helix do not spring back.

[0004] Slow-wave assembly extrusion involves assembling the helix and clamping rod into the tube shell to achieve good contact between the tube shell, clamping rod, and helix. There are two existing extrusion methods: cold and hot. The cold assembly methods include: (1) using the pre-elastic deformation of the thin-walled tube shell, and then springing back after assembly to achieve extrusion and clamping of the clamping rod and helix; (2) using tooling to extrude and deform the connecting ring of the composite tube shell to achieve the purpose of extrusion and clamping; (3) using two oblique wedges to insert for extrusion and clamping. The hot extrusion methods include: (1) after the thin-walled tube shell is first assembled with a cold clearance fit, it is placed in a mold with a small coefficient of expansion for high-temperature extrusion and then cooled and clamped; (2) using the thermal expansion and contraction of the tube shell to achieve clamping and fixing of the clamping rod and helix.

[0005] Existing patent CN101976645B discloses an assembly method for a spiral composite shell slow-wave circuit. First, three clamping rods and a spiral are locked and positioned using a metal rod and a petal-shaped assembly mold. Then, the positioned clamping rods and spiral are pushed into the composite shell. Next, the metal rods and petals are removed, connecting the outer wall of the spiral to the inner wall of the clamping rods, and the outer wall of the clamping rods to the inner wall of the composite shell. Finally, two metal wedges are inserted into grooves on the inner wall of the composite shell. The metal wedges apply force to the clamping rods, thereby making the spiral, clamping rods, and composite shell more firmly connected by pressing them together with the two wedges.

[0006] However, in traditional cold extrusion or hot extrusion methods, the helix is ​​made of pure tungsten or pure molybdenum and has undergone full annealing. This results in poor mechanical strength, low contact stress, and high contact thermal resistance in the slow-wave assembly. Furthermore, traditional hot extrusion requires atmospheric or vacuum protection, leading to poor high-temperature alignment accuracy, easy splitting of the clamping rod during extrusion, easy deformation of the helix, easy wear of the attenuator, and easy deviation in the extrusion position. These factors contribute to low yield and poor consistency of the slow-wave assembly. Summary of the Invention

[0007] To address the problems of poor heat dissipation and low yield of existing slow-wave components, this invention provides a cold extrusion method for slow-wave components used in traveling wave tubes.

[0008] This invention provides a cold extrusion method for slow-wave components for traveling wave tubes, comprising: winding a helix based on a preset springback amount; after winding, bonding the helix to a core rod with adhesive, releasing the fixing at both ends of the helix to obtain a helix with a core rod; fitting a clamping rod onto the outer wall of the helix with the core rod, clamping the helix with the clamping rod using multiple sets of clamping components, and inserting both ends of the helix with the clamping rod into a guide mold and a limiting mold respectively; pushing the positioned clamping rod and the helix into a composite tube shell, ensuring the positional accuracy of the helix, clamping rod, and composite tube shell, and removing the multiple sets of clamping components and the guide rod. The assembly is obtained by applying the mold and the limiting mold; the assembled assembly is immersed in the first organic solvent to remove the glue; the spiral outer diameter springs back, causing the spiral, clamping rod and composite tube shell to automatically clamp, resulting in the extruded assembly with an interference fit between 0.01mm and 0.03mm; the extruded assembly is then immersed in the second organic solvent, and the spiral springs back and the mandrel loosens and is removed; the assembly after removing the mandrel is cleaned to remove excess glue; when the relative position accuracy of the spiral and the standing wave ratio of the slow wave assembly both meet the predetermined requirements, the cold extrusion of the slow wave assembly is completed.

[0009] According to an embodiment of the present invention, the springback amount is obtained by analyzing the springback amount of the outer diameter and pitch of the spiral without high-temperature setting, with a springback range of 0.01-0.03 mm; or the springback amount is obtained by heat-treating the spiral at a setting temperature below 1300°C.

[0010] According to an embodiment of the present invention, the spiral is made of tungsten-molybdenum material.

[0011] According to an embodiment of the present invention, there are multiple clamping rods, and the multiple clamping rods are evenly distributed on the outer circumference of the spiral with the core rod; the inner wall of the composite tube shell is a cylindrical hole, and the outer wall of the multiple clamping rods abuts against the cylindrical hole.

[0012] According to an embodiment of the present invention, each clamping assembly includes a first V-groove mold and a second V-groove mold that are matched with each other; wherein, the first V-groove mold is located at the lower part and has a V-groove, and the second V-groove mold is located at the upper part, and the first V-groove mold and the second V-groove mold together clamp the spiral wire on which the clamping rod is sleeved.

[0013] According to an embodiment of the present invention, after the two ends of the spiral with clamping rods are respectively inserted into the guide mold and the limiting mold, the method further includes: using screws to fasten multiple sets of clamping components, clamping rods and spiral with core rods.

[0014] According to an embodiment of the present invention, the clamping rod is sleeved on the outer wall of the spiral with the core rod, and the positioned clamping rod and spiral are pushed into the composite tube shell, both of which adopt a clearance fit assembly method.

[0015] According to an embodiment of the present invention, at least one of the first organic solvent and the second organic solvent is acetone.

[0016] According to an embodiment of the present invention, cleaning the component after removing the core rod includes: immersing the component after removing the core rod again in a second organic solvent, cleaning it with ultrasound, and then taking it out and drying it.

[0017] According to an embodiment of the present invention, the predetermined requirement for the standing wave ratio (VSWR) of the slow wave component is less than 1.5.

[0018] Compared with the prior art, the cold extrusion method for slow-wave components for traveling wave tubes provided by the present invention has at least the following beneficial effects:

[0019] (1) The slow wave component cold extrusion method is adopted. The spiral is not shaped and the spiral is pure metal. The winding deformation will improve the mechanical properties such as the elastic limit of the tungsten spiral by 30%, the contact stress by 20%, and the contact thermal resistance by more than 30%. The heat dissipation performance of the slow wave component is greatly improved, and the output power level is increased from 100W to 800W.

[0020] (2) The slow-wave module cold extrusion method is adopted, and the extrusion is completed in a cold state, which solves the problems of oxidation at high temperature, damage to clamping rods, spirals, attenuators and poor position accuracy in hot extrusion. This can improve the consistency and yield of slow-wave modules.

[0021] (3) The equipment technology required for the cold extrusion process of slow wave components is mature, the social support is complete, and the process is easy to implement, which helps to promote the application of this technology. Attached Figure Description

[0022] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0023] Figure 1 A flowchart illustrating a cold extrusion method for a slow-wave assembly for a traveling wave tube according to an embodiment of the present invention is shown schematically.

[0024] Figure 2 The diagram schematically illustrates the structure of a helix 1 with a core rod 2 according to an embodiment of the present invention, wherein (a) is a partial enlarged view of the helix with a core rod, and (b) is an overall view of the helix with a core rod;

[0025] Figure 3 A schematic diagram illustrating the structure of a pre-fixed spiral according to an embodiment of the present invention is shown.

[0026] Figure 4 A schematic diagram of a helical pre-assembly according to an embodiment of the present invention is shown.

[0027] [Explanation of reference numerals in the attached figures]

[0028] 1-Helix; 2-Core rod; 3-Clamping rod; 41-First V-groove mold; 42-Second V-groove mold; 5-Guide mold; 6-Limiting mold; 7-Screw; 8-Composite tube shell. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0030] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0031] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0032] To address the problems of poor heat dissipation and low yield in existing slow-wave components, this invention provides a cold extrusion method for slow-wave components used in traveling wave tubes. First, based on a preset springback amount, the wound helix and core rod are bonded together with adhesive. The clamping rod and the helix with the core rod are then sequentially placed into multiple sets of clamping assemblies. Guide molds and limiting molds are assembled at both ends, and screws are used to lock the multiple sets of clamping assemblies, clamping rods, and the helix with the core rod. Next, the positioned clamping rods and helix are pushed into the composite tube shell. Multiple sets of clamping assemblies are then sequentially removed. After assembly, the guide molds and limiting molds are removed. The assembled component is immersed in an organic solvent such as acetone to remove the adhesive. The springback of the helix's outer diameter causes the helix, clamping rods, and composite tube shell to automatically clamp together. Finally, the core rod is removed, completing the cold extrusion of the slow-wave component.

[0033] Figure 1 A flowchart illustrating a method for cold extrusion of a slow-wave assembly for a traveling wave tube according to an embodiment of the present invention is shown.

[0034] like Figure 1 As shown, the cold extrusion method for a slow-wave assembly for a traveling wave tube according to this embodiment may include operations S1 to S7.

[0035] In operation S1, the spiral 1 is wound based on the preset springback amount.

[0036] In this embodiment of the invention, the springback amount is obtained by analyzing the springback amount of the outer diameter and pitch of the spiral 1 without high-temperature setting, and the springback range is 0.01-0.03 mm; or the springback amount is obtained by heat-treating the spiral 1 at a setting temperature below 1300°C.

[0037] Therefore, depending on the interference fit requirements, the spiral 1 can be unshaped, or it can be heat-treated at a setting temperature below 1300℃ to obtain different springback values, resulting in extrusions with different interference fits. Without high-temperature setting, it exhibits high mechanical strength, good heat dissipation, and high power resistance.

[0038] Through embodiments of the present invention, by analyzing the springback of the outer diameter and pitch of the helix during the design phase without high-temperature setting, the springback amount is taken into account in the winding parameters during the helix winding stage. After winding the helix 1, the final dimensions of the springbacked helix 1 can meet the design requirements.

[0039] In this embodiment of the invention, the helix 1 is made of tungsten-molybdenum material. The strength of the helix after winding with tungsten-molybdenum material is 30% of the strength of the helix after shaping. The extrusion clamping force of the slow-wave assembly is increased by 20%, and the thermal resistance is reduced by more than 30%. The maximum temperature of the slow-wave assembly is reduced by more than 100°C. The output power rating is increased from 100W to more than 400W.

[0040] In operation S2, after winding, the spiral 1 is glued to the core rod 2, and the two ends of the spiral 1 are released to obtain the spiral 1 with the core rod 2.

[0041] Figure 2 A schematic diagram of the structure of the helix 1 with the core rod 2 according to an embodiment of the present invention is shown, wherein (a) is a partial enlarged view of the helix with the core rod, and (b) is an overall view of the helix with the core rod.

[0042] like Figure 2 As shown, the wound spiral 1 is bonded to the core rod 2. After removing the fixation at both ends, it can be ensured that the spiral 1 with the core rod 2 has no springback.

[0043] In operation S3, a clamping rod 3 is fitted onto the outer wall of the spiral 1 with the core rod 2, and multiple sets of clamping components are used to clamp the spiral 1 with the clamping rod 3 fitted onto it. The two ends of the spiral 1 with the clamping rod 3 fitted onto it are respectively inserted into the guide mold 5 and the limiting mold 6.

[0044] Through the embodiments of the present invention, the wound spiral 1 is firmly bonded with glue. By reducing the length of the spiral 1 winding and binding process, it can be ensured that the spiral 1 and the core rod 2 are bonded without loosening.

[0045] This operation is a pre-fixing operation for spiral line 1. Figure 3 A schematic diagram illustrating the structure of a pre-fixed spiral according to an embodiment of the present invention is shown.

[0046] like Figure 3 As shown, in this embodiment of the invention, each clamping assembly includes a first V-groove mold 41 and a second V-groove mold 42 that are matched with each other; wherein, the first V-groove mold 41 is located at the lower part and has a V-groove, and the second V-groove mold 42 is located at the upper part, and the first V-groove mold 41 and the second V-groove mold 42 together clamp the spiral 1 on which the clamping rod 3 is sleeved.

[0047] In this embodiment of the invention, after the two ends of the spiral 1 equipped with the clamping rod 3 are respectively inserted into the guide mold 5 and the limiting mold 6, the invention further includes: using screws 7 to fasten multiple sets of clamping components, clamping rods 3 and spiral 1 with core rod 2.

[0048] Specifically, the clamping rod 3 and the spiral 1 with the core rod 2 are sequentially placed into multiple sets of first V-groove molds 41 and second V-groove molds 42, and guide molds 5 and limiting molds 6 are assembled at both ends. Then, screws 7 are used to lock the multiple sets of first V-groove molds 41, second V-groove molds 42, clamping rod 3 and spiral 1 with the core rod 2.

[0049] In operation S4, the positioned clamping rod 3 and spiral 1 are pushed into the composite tube shell 8 to ensure the positional accuracy of the spiral 1, clamping rod 3 and composite tube shell 8. Multiple sets of clamping components, guide mold 5 and limit mold 6 are removed to obtain the assembled components.

[0050] This operation is a pre-assembly operation for spiral line 1. Figure 4 A schematic diagram of a helical pre-assembly according to an embodiment of the present invention is shown.

[0051] like Figure 4 As shown, in this embodiment of the invention, there are multiple clamping rods 3, and the multiple clamping rods 3 are evenly distributed on the outer circumference of the spiral line 1 with the core rod 2; the inner wall of the composite tube shell 8 is a cylindrical hole, and the outer wall of the multiple clamping rods 3 abuts against the cylindrical hole.

[0052] It should be noted that, Figure 4 The diagram shows three clamping rods 3, but in some embodiments, there may be multiple clamping rods 3. The specific number is not limited by the present invention.

[0053] Specifically, the positioned clamping rod 3 and spiral 1 are pushed into the composite tube shell 8, and multiple sets of first V-groove molds 41 and second V-groove molds 42 are removed in sequence. After assembly, the guide mold 5 and the limiting mold 6 are removed.

[0054] In operation S5, the assembled component is immersed in the first organic solvent to remove the glue. Through the rebound of the outer diameter of the spiral 1, the spiral 1, the clamping rod 3 and the composite tube shell 8 are automatically clamped to obtain the extruded component. The interference of the extruded component is between 0.01mm and 0.03mm.

[0055] The first organic solvent can be, for example, acetone. The assembled components are placed in acetone to remove the glue. After the outer diameter of the spiral 1 springs back, the spiral 1, the clamping rod 3, and the composite tube shell 8 are automatically clamped.

[0056] In operation S6, the extruded component is immersed in the second organic solvent. After the spiral 1 is released and the core rod 2 is loosened, it is removed. The component after removing the core rod 2 is cleaned to remove excess glue.

[0057] The second organic solvent can be, for example, acetone. The extruded components are immersed in acetone, the spiral 1 is sprung open and then squeezed tight, and the core rod 2 is loosened and then removed.

[0058] In this embodiment of the invention, cleaning the component after removing the core rod 2 includes: immersing the component after removing the core rod 2 into a second organic solvent again, cleaning it with ultrasound, and then taking it out and drying it.

[0059] During operation S7, when the relative position accuracy of the detected spiral 1 and the standing wave ratio of the slow wave component both meet the predetermined requirements, the cold extrusion of the slow wave component is completed.

[0060] In this embodiment of the invention, the predetermined requirement for the standing wave ratio (SWR) of the slow-wave component is less than 1.5. Therefore, when the relative position accuracy of the detected helix 1 meets the predetermined requirement, and the detected SWR of the slow-wave component is less than 1.5, the cold extrusion of the slow-wave component is completed.

[0061] In this embodiment of the invention, the clamping rod 3 is sleeved on the outer wall of the spiral 1 with the core rod 2, and the positioned clamping rod 3 and spiral 1 are pushed into the composite tube shell 8. Both are assembled by clearance fit, with a clearance of about 0.01 mm.

[0062] The above is merely an illustrative example, and the present invention is not limited thereto. For example, in other embodiments, other assembly methods can be used to push the positioned clamping rod 3 and the spiral 1 into the composite tube shell 8. Furthermore, in other embodiments, besides using glue, other bonding methods that allow for easy subsequent removal can be used to adhere the spiral 1 to the core rod 2.

[0063] Furthermore, comparison with existing assembly methods for slow-wave circuits using spiral composite tubes reveals that the method of this invention is suitable for the fabrication of traveling-wave tube slow-wave components, increasing yield by 30% and improving consistency, making it suitable for mass production. This invention has been applied to a Ku400W traveling-wave tube, resulting in stable and reliable performance and a significantly improved yield.

[0064] As can be seen from the above technical solution, the present invention has the following beneficial effects:

[0065] (1) The slow wave component cold extrusion method is adopted. The spiral is not shaped and the spiral is pure metal. The winding deformation will improve the mechanical properties such as the elastic limit of the tungsten spiral by 30%, the contact stress by 20%, and the contact thermal resistance by more than 30%. The heat dissipation performance of the slow wave component is greatly improved, and the output power level is increased from 100W to 800W.

[0066] (2) The slow-wave module cold extrusion method is adopted, and the extrusion is completed in a cold state, which solves the problems of oxidation at high temperature, damage to clamping rods, spirals, attenuators and poor position accuracy in hot extrusion. This can improve the consistency and yield of slow-wave modules.

[0067] (3) The equipment technology required for the cold extrusion process of slow wave components is mature, the social support is complete, and the process is easy to implement, which helps to promote the application of this technology.

[0068] The accompanying drawings show some block diagrams and / or flowcharts. It should be understood that some blocks or combinations thereof in the block diagrams and / or flowcharts can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when executed by the processor, these instructions can create means for implementing the functions / operations described in these block diagrams and / or flowcharts.

[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. Furthermore, the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0070] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cold extrusion method for a slow-wave assembly for a traveling wave tube, characterized in that, include: The spiral is wound based on a preset springback amount; After winding, the spiral is glued to the core rod, and the two ends of the spiral are released to obtain a spiral with a core rod. A clamping rod is fitted onto the outer wall of the spiral with the core rod. Multiple sets of clamping assemblies are used to clamp the spiral with the clamping rod. The two ends of the spiral with the clamping rod are respectively inserted into the guide mold and the limiting mold. Push the positioned clamping rod and spiral into the composite tube shell to ensure the positional accuracy of the spiral, clamping rod and composite tube shell. Remove the multiple sets of clamping components, guide mold and limiting mold to obtain the assembled components. The assembled component is immersed in a first organic solvent to remove the glue. The spiral, clamping rod and composite tube shell are automatically clamped by the rebound of the outer diameter of the spiral to obtain the extruded component. The interference of the extruded component is between 0.01mm and 0.03mm. The extruded component is immersed in the second organic solvent. After the spiral springs open and the core rod is loosened, it is removed. The component after removing the core rod is cleaned to remove excess glue. When the relative position accuracy of the detected spiral and the standing wave ratio of the slow wave component both meet the predetermined requirements, the cold extrusion of the slow wave component is completed.

2. The cold extrusion method for slow-wave components for traveling wave tubes according to claim 1, characterized in that, The springback amount is obtained by analyzing the springback of the outer diameter and pitch of the spiral thread under high-temperature setting conditions, with a springback range of 0.01-0.03 mm; or The springback is obtained by heat-treating the spiral at a setting temperature below 1300°C.

3. The cold extrusion method for slow-wave components for traveling wave tubes according to claim 1, characterized in that, The spiral is made of tungsten-molybdenum material.

4. The cold extrusion method for slow-wave components for traveling wave tubes according to claim 1, characterized in that, There are multiple clamping rods, and the multiple clamping rods are evenly distributed on the outer circumference of the spiral with the core rod; The inner wall of the composite tube shell is a cylindrical hole, and the outer wall of the plurality of clamping rods abuts against the cylindrical hole.

5. The cold extrusion method for slow-wave components for traveling wave tubes according to claim 1, characterized in that, Each set of clamping components includes a first V-groove mold and a second V-groove mold that match each other; The first V-groove mold is located at the bottom and has a V-groove, while the second V-groove mold is located at the top. The first V-groove mold and the second V-groove mold together clamp the spiral wire with the clamping rod.

6. The cold extrusion method for slow-wave components for traveling wave tubes according to claim 1, characterized in that, After the two ends of the spiral wire equipped with clamping rods are respectively inserted into the guide mold and the limiting mold, the process further includes: The multiple clamping assemblies, clamping rods, and helical cords with core rods are secured with screws.

7. The cold extrusion method for slow-wave components for traveling wave tubes according to claim 1, characterized in that, The clamping rod is sleeved on the outer wall of the spiral with the core rod, and the positioning clamping rod and spiral are pushed into the composite tube shell, both of which adopt a clearance fit assembly method.

8. The cold extrusion method for slow-wave components for traveling wave tubes according to claim 1, characterized in that, At least one of the first organic solvent and the second organic solvent is acetone.

9. The cold extrusion method for slow-wave components for traveling wave tubes according to claim 1, characterized in that, The cleaning of the components after removing the core rod includes: The assembly after removing the core rod is immersed again in the second organic solvent and cleaned using ultrasound. After removal, it is dried.

10. The cold extrusion method for slow-wave components for traveling wave tubes according to claim 1, characterized in that, The predetermined requirement for the standing wave ratio (VSWR) of the slow wave component is less than 1.5.

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