Encapsulation mold for traveling wave tube, mold preparation method and encapsulation method

Abstract

The invention discloses a pouring and sealing mold for a traveling wave tube, a mold preparation method and a pouring and sealing method. The pouring and sealing mold comprises a mold base body and a film layer structure. The mold base body is of a hollow tubular structure, an inner cavity of the mold base body is an encapsulation channel, one end of the mold base body is connected with a traveling wave tube in an inserted mode, and the other end of the mold base body is a material injection end. At least one opening hole is formed in the pipe wall of the mold base body, the opening hole is communicated with the filling and sealing channel, and the film layer structure covers the opening hole; the film layer structure can allow water vapor and air to pass through and enter the potting channel, so that water molecules act on the potting material in the potting channel, and the curing speed and uniformity of the potting material are improved. The pouring mold is improved on the basis of an original pouring mold, the problem of low-voltage discharge in the using process of the traveling wave tube is solved, the performance and the service life of the traveling wave tube are guaranteed, the influence of the low-voltage discharge phenomenon on the service continuity of a satellite load system is avoided, and the reliability of the satellite load system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of traveling wave tube manufacturing, and more specifically, to a potting mold for a traveling wave tube, a mold preparation method and a potting method. Background Art

[0002] Space traveling wave tubes are key components of communication satellites, navigation satellites, atmospheric sounding satellites and military reconnaissance satellites. Their operating voltage is usually as high as tens of thousands of volts, and their service life can be as long as 15 years or more. In addition, they are in the space environment for a long time and have to deal with complex thermodynamic environmental stresses and possible cosmic radiation. In order to ensure that space traveling wave tubes can work stably in the space environment for a long time, the high-voltage capacitors that match them also need to have many characteristics such as high voltage resistance, small size, high stability, high reliability and strong environmental adaptability.

[0003] Low-voltage discharge will occur in space traveling wave tubes during use. The low-voltage discharge phenomenon will not only affect the performance and service life of the space traveling wave tube, but also because the space traveling wave tube is the core component of the satellite transponder, the low-voltage discharge phenomenon will also have an adverse effect on the business continuity of the satellite payload system and reduce the reliability of the satellite payload system. In summary, the hazards caused by low-voltage discharge of space traveling wave tubes cannot be ignored. Summary of the invention

[0004] In view of the above problems, one object of the present invention is to provide a potting mold for a traveling wave tube.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned potting mold for a traveling wave tube.

[0006] Another object of the present invention is to provide a potting method for potting electrode terminals of a traveling wave tube using the potting mold for the traveling wave tube.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] According to one aspect of the present invention, there is provided a potting mold for a traveling wave tube, comprising:

[0009] Mold substrate, and film layer structure;

[0010] The mold base is a hollow tubular structure, the inner cavity of which is a potting channel, one end of the mold base is plug-connected to the traveling wave tube, and the other end of the mold base is an injection end;

[0011] The tube wall of the mold base is provided with at least one opening, the opening is communicated with the potting channel, and the film layer structure covers the opening;

[0012] The membrane structure can allow water vapor and air to pass into the potting channel, so that water molecules act on the potting material in the potting channel, thereby improving the curing speed and uniformity of the potting material.

[0013] In addition, an optional solution is that the film layer structure is adhered and fixed to the inner wall of the mold base.

[0014] In addition, an optional solution is that the shape of the opening is one or more of circular, rectangular, and elliptical.

[0015] In addition, an optional solution is that a plurality of openings are evenly distributed on the tube wall of the mold base and are arranged around the central axis of the mold base.

[0016] In addition, the optional solution is that the area of ​​a single opening ranges from 3-300mm 2 The areas of the openings formed on the tube wall of the mold base may be the same or different.

[0017] In addition, an optional solution is that the number of openings formed in the tube wall of the mold base is in the range of 1-100, and each opening is covered with a film layer structure.

[0018] In addition, an optional solution is that the membrane layer structure is made of nylon woven material, polyester fiber fabric or microporous polytetrafluoroethylene.

[0019] According to another aspect of the present invention, a mold preparation method is provided for preparing a potting mold for a traveling wave tube, comprising the following steps:

[0020] Step 1: making a mold base according to the size of the part of the traveling wave tube to be potted;

[0021] Step 2, opening a hole in the tube wall of the mold base;

[0022] Step 3: Select a waterproof and breathable membrane as the membrane structure according to the size of the openings, and ensure that each opening is covered by the membrane structure;

[0023] Step 4: clean the mold base and bond the film structure to the inner side of the mold base by bonding material.

[0024] According to another aspect of the present invention, a potting method is provided, wherein an electrode terminal of a traveling wave tube is potted using a potting mold for the traveling wave tube, comprising the following steps:

[0025] Step 1: plug and connect the mold base to the electrode terminal of the traveling wave tube;

[0026] Step 2, leading the wire connected to the electrode terminal of the traveling wave tube out from the injection end of the mold base;

[0027] Step 3, injecting the potting material into the potting channel from the injection end of the mold base;

[0028] Step 4: Wait for the potting material to cure in a curing environment, remove the potting mold, and the potting is completed.

[0029] In addition, an optional solution is that the curing environment is:

[0030] Temperature 20℃-80℃, humidity 20%-50%;

[0031] The curing time is 8-96h.

[0032] The beneficial effects of the present invention are as follows:

[0033] In view of the technical problems existing in the prior art, the present invention provides a potting mold, a mold preparation method and a potting method for a traveling wave tube, which make improvements on the basis of the original potting mold, solve the problem of low-voltage discharge during the use of the traveling wave tube, make the potting colloid cure faster and more uniformly, improve the uniformity of the colloid after curing, ensure the performance and service life of the traveling wave tube, avoid the influence of low-voltage discharge on the business continuity of the satellite payload system, and improve the reliability of the satellite payload system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0035] Figure 1 A schematic diagram showing the structure of a traveling wave tube electrode terminal.

[0036] Figure 2 The schematic diagram shows the structure after the traveling wave tube electrode terminal is potted.

[0037] Figure 3 A schematic structural diagram of a potting mold provided by an embodiment of the present invention is shown.

[0038] Figure 4 A schematic diagram showing the structure of a potting mold provided by an embodiment of the present invention installed on a traveling wave tube.

[0039] Figure 5 A line graph showing the comparison of the degree of cure of the comparative examples and the examples.

[0040] Figure 6 A schematic diagram showing the delamination of the potting colloid and the conductor during the use of the existing traveling wave tube. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0042] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly stipulated and limited, a first feature being “on” or “under” a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them.

[0044] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0045] The low-voltage discharge phenomenon of the traveling wave tube will bring great harm to the traveling wave tube itself and the satellite payload system. In order to avoid the occurrence of low-voltage discharge problems, improve the performance of the traveling wave tube itself, and ensure the reliability of the satellite payload system, the applicant has found through investigation and analysis that the cause of the low-voltage discharge problem is the stratification between the insulation layer of the connecting wire at the electrode terminal of the traveling wave tube and the potting colloid, which leads to insulation failure and ultimately causes low-voltage discharge.

[0046] Since the electron gun and collector electrodes of the traveling wave tube need to be loaded with high voltage, the external terminals of the tube that connect the electrodes need to be potted after welding with the wires to achieve the purpose of insulation protection. The working life of the traveling wave tube is generally more than 15 years. When working in orbit, the potting colloid will withstand temperature cycles from -60°C to 150°C. If the performance of the potting colloid is uneven, it will cause internal stress in the potting colloid under high and low temperature cycle conditions, accelerate the aging of the potting colloid, and cause stratification between the potting colloid and the insulation layer of the wire (such as Figure 6As shown, there is a gap 400 between the potting colloid 300 and the wire 200, which causes insulation failure. When used in a high-voltage environment, the risk of partial discharge will be aggravated, and low-voltage discharge will occur during the production process of the traveling wave tube.

[0047] The performance of the potting colloid is affected by the potting quality. The potting speed, curing speed and curing temperature of the potting colloid will affect the potting quality, resulting in delamination between the potting colloid and the wire insulation layer, causing insulation failure and low-voltage discharge.

[0048] Therefore, in order to avoid the occurrence of low-voltage discharge, a method to improve the potting quality can be selected. At present, the material for the potting of the traveling wave tube generally adopts a condensed two-component room temperature vulcanized silicone rubber, with 10% of dimethyl silane as the base material, and silicate curing agent and filler seal are added to form component A, and component B is an organic tin catalyst (such as dimethyl tin dilaurate). The main factors affecting its curing speed are the nature and dosage of the catalyst, and the temperature and humidity in the environment will also have a certain impact on the curing speed. A common method to improve the potting quality in the prior art is to use vacuum potting to reduce the bubbles inside the colloid, but this requires that the potting speed under vacuum conditions cannot be too fast, otherwise the bubbles are not easy to discharge. The presence of bubbles in the potting glue will reduce the potting quality and affect the long-term reliability of the potting glue. However, a slow potting speed will also affect the curing speed of the potting glue. A slow curing speed will cause uneven curing of the potting colloid, affect the performance of the potting colloid, cause the potting glue and the wire insulation layer to be delaminated, and cause low-voltage discharge. If the curing speed is increased by increasing the amount of curing agent, the bubbles cannot be completely discharged due to the too fast curing speed, which will also affect the potting quality. In addition, since the traveling wave tube is generally potted with multiple electrode terminals, the height difference between different terminals is relatively large, which will cause the overall height of the potting glue to be large, up to 40mm. The excessive potting range will also slow down the curing speed of the potting glue, affecting the uniformity of the potting glue performance. In summary, the existing means cannot solve the problem of low-voltage discharge.

[0049] In view of the defects of the prior art, the present invention provides a potting mold for a traveling wave tube, which is used for potting after the electrode terminal and the wire are welded and connected to achieve the purpose of insulation protection. Figure 1-5 As shown, the potting mold includes a mold base 1 and a film structure 2. The mold base 1 is a hollow tubular structure, which is the main structure of the potting mold. The inner cavity of the mold base 1 is a potting channel. One end of the mold base 1 is plug-connected with the traveling wave tube 100, and the other end is an injection end 12. The potting material enters the potting channel from the injection end 12 and contacts the electrode terminals of the traveling wave tube and the wires connected to the electrode terminals and is cured in a suitable environment to complete the potting of the traveling wave tube electrode terminals.

[0050] The tube wall of the mold base 1 is provided with at least one opening 11, and the opening 11 is connected to the potting channel, and the membrane structure 2 covers the opening 11. The membrane structure 2 is a waterproof and breathable membrane, which can allow water vapor and air to pass into the potting channel and contact the potting material, so that water molecules act on the potting material in the potting channel, so that the potting material can quickly and evenly complete the curing, and improve the uniformity of the colloid performance after curing. The potting material used in the embodiment of the present invention is a two-component room temperature curing condensation type dealcoholized silicone rubber, and the catalyst is dibutyltin dilaurate. When the potting material is used, the base material and the vulcanizing agent are mixed in a certain proportion, gradually thickened at room temperature, and finally vulcanized to form an elastomer. When the vulcanizing agent and its dosage remain unchanged, increasing the ambient humidity can accelerate the vulcanization speed and shorten the vulcanization time. An opening 11 is formed in the tube wall of the mold base 1, and a waterproof and breathable membrane structure 2 is covered on the opening 11. Compared with the traditional potting mold in which the curing starts from the injection end, the potting mold provided in this embodiment can enable water molecules in the air to contact with various surfaces of the potting material in the potting channel, shorten the vulcanization time, increase the curing speed of the potting material, and enable the potting material to be uniformly cured, thereby ensuring the uniformity of the colloid performance after curing and improving the long-term reliability of the potting colloid.

[0051] In one embodiment, the film layer structure 2 is fixed to the inner wall of the mold base 1, covering each opening 11, and preferably a double-sided tape is used to fix the film layer structure 2. The film layer structure 2 can be cut into an integral structure that covers all openings 11 at the same time, or it can be cut into an independent structure that covers each opening 11 separately, and the specific selection can be made according to the size of the mold base 1 and the difficulty of the process.

[0052] In a specific embodiment, the shape of the opening 11 can be one or more of a circle, a rectangle, an ellipse or other complex shapes. The larger the area of ​​the opening 11, the faster the curing speed of the potting material. When the shape and size of the openings 11 on the same mold base 1 are the same, the potting material is cured more uniformly.

[0053] In one embodiment, multiple openings are evenly distributed on the tube wall of the mold base 1 and arranged around the central axis of the mold base 1 to ensure that the potting material in the potting channel can evenly contact the water molecules in the air, ensure the speed and curing uniformity of the potting material, and obtain a colloid with uniform performance.

[0054] In one embodiment, the area of ​​a single opening 11 ranges from 3 to 300 mm. 2 The areas of the openings on the tube wall of the mold base 1 may be the same or different, but the curing uniformity of the potting material when the openings have the same areas is better than the curing uniformity of the potting material when the openings have different areas.

[0055] In one embodiment, the number of openings 11 formed in the tube wall of the mold base 1 ranges from 1 to 100, and each opening 11 is covered with a film structure. In order to increase the curing speed of the potting material and the uniformity of the curing of the potting material, the total area of ​​the openings 11 should be as large as possible without affecting the strength of the mold base 1. In this case, the area of ​​a single opening 11 is inversely proportional to the number of openings 11, and can be designed according to the specific conditions in the production process. Preferably, the total area of ​​the openings 11 is 5%-60% of the area of ​​the tube wall of the mold base 1.

[0056] In one embodiment, the membrane structure 2 is a waterproof and breathable material. The waterproof and breathable material described here refers to ensuring that only gas molecules can pass through, while larger liquid particles such as water droplets are effectively blocked. The waterproof and breathable material is processed by a special process to form a microporous structure. The microporous structure is the key to the waterproof function. The size of the micropores is much smaller than the diameter of the water droplets, so the water droplets cannot penetrate through these micropores to the other side of the membrane. At the same time, these micropores are large enough to allow water vapor, air and other gases to pass through, thereby achieving a breathable effect. The membrane structure 2 uses a waterproof and breathable material. On the one hand, it can prevent the uncured potting material from seeping out, and on the other hand, it can ensure that water vapor can enter the potting channel so that the potting material can be quickly and evenly cured. Specifically, the waterproof and breathable material can be a waterproof and breathable membrane made of waterproof and breathable materials such as nylon woven material, polyester fiber fabric or microporous polytetrafluoroethylene.

[0057] The advantages of the encapsulation mold provided by the embodiment of the present invention will be described below with reference to examples:

[0058] Comparative Example

[0059] The traditional potting mold made of pure polytetrafluoroethylene material adopts vacuum potting method, and the curing conditions are temperature 20°C, humidity 60%, and curing time 24h.

[0060] Example

[0061] The potting mold provided in this embodiment has a circular opening, and the area of ​​a single opening is 1mm 2 The number of openings is 20, and the vacuum potting method is adopted. The curing conditions are temperature 20℃, humidity 60%, and curing time 24h.

[0062] Analyze the cured potting colloid and perform hardness test every 3mm. Figure 5 As shown in the figure, the horizontal axis is the colloid depth (mm), the vertical axis is the Shore hardness (HA), a is an embodiment, and b is a comparative example. It can be obviously seen that the potting colloid obtained by potting using the potting module provided by the embodiment of the present invention has a faster curing speed and more uniform curing.

[0063] Another embodiment of the present invention provides a mold preparation method, which is used to prepare the encapsulation mold in the above embodiment, and specifically includes the following steps:

[0064] Step 1: manufacturing a mold base 1 according to the size of the part of the traveling wave tube 100 to be potted;

[0065] Step 2, opening a hole 11 in the tube wall of the mold base 1;

[0066] Step 3: Select a waterproof and breathable membrane as the membrane structure 2 according to the size of the opening 11, and ensure that each opening 11 is covered by the membrane structure 2;

[0067] Step 4: clean the mold base 1 and bond the film structure 2 to the inner side of the mold base 1 by using bonding material.

[0068] In one embodiment, in step 1, Figure 4 As described above, the inner diameter of the mold base 1 is designed according to the size of the portion of the traveling wave tube 100 to be potted, so that it can be sleeved on the traveling wave tube 100 and accommodate the electrode terminals and the wires in the potting channel.

[0069] In one embodiment, in step 2, the shape of the opening 11 can be one or more of a circle, rectangle, ellipse or other complex shapes. The larger the area of ​​the opening 11, the faster the curing speed of the potting material. When the openings 11 on the same mold base 1 have the same shape and size, the potting material is cured more uniformly. Multiple openings are evenly distributed on the tube wall of the mold base 1 and arranged around the central axis of the mold base 1 to ensure that the potting material in the potting channel can evenly contact the water molecules in the air, ensure the speed and uniformity of the curing of the potting material, and obtain a colloid with uniform performance. The area range of a single opening 11 is 3-300mm 2 , the areas of the openings on the tube wall of the mold base 1 can be the same or different, but the curing uniformity of the potting material when the areas of the openings are the same is better than the curing uniformity of the potting material when the areas of the openings are different. The number of openings 11 opened on the tube wall of the mold base 1 ranges from 1 to 100, and each opening 11 is covered with a film structure. In order to increase the curing speed of the potting material and the curing uniformity of the potting material, the total area of ​​the openings 11 should be as large as possible without affecting the strength of the mold base 1. In this case, the area of ​​a single opening 11 is inversely proportional to the number of openings 11, and can be designed according to the specific conditions in the production process. Preferably, the total area of ​​the openings 11 is 5%-60% of the area of ​​the tube wall of the mold base 1.

[0070] In one embodiment, in step three, the film layer structure 2 can be an integral structure that covers all openings 11 at the same time, or can be cut into independent structures that cover each opening 11 separately. The specific selection can be based on the size of the mold base 1 and the difficulty of the process.

[0071] In one embodiment, in step 4, the film structure 2 is pasted on the inner wall of the mold base 1 by double-sided tape to cover all the openings 11. During the pasting process, the film structure 2 should be kept flat.

[0072] Another embodiment of the present invention provides a potting method, which uses the potting mold in the above embodiment to pot the electrode terminal of the traveling wave tube, including the following steps:

[0073] Step 1, such as Figure 4 As shown, the mold base 1 is plugged and connected to the electrode terminal 101 of the traveling wave tube 100;

[0074] Step 2: Lead the wire 200 connected to the electrode terminal 101 of the traveling wave tube 100 out from the injection end of the mold base 1;

[0075] Step 3, injecting the potting material into the potting channel from the injection end of the mold base 1;

[0076] Step 4: Wait for the potting material to cure in a curing environment, remove the potting mold, and the potting is completed. Figure 2 In the structure shown, the potting colloid 300 is wrapped around the outside of the electrode terminal 101 and the wire 200 to play the role of insulation protection.

[0077] In one embodiment, the curing environment in step 4 refers to: temperature conditions of 20° C.-80° C., and humidity conditions of 20%-50%.

[0078] In this embodiment, the curing time is 8-96 hours.

[0079] The potting mold, mold preparation method and potting method for a traveling wave tube provided in the embodiments of the present invention are improvements made on the basis of the original potting mold, and solve the problem of low-voltage discharge during the use of the traveling wave tube, so that the curing speed of the potting colloid is faster and the curing is more uniform, the uniformity of the colloid after curing is improved, the performance and service life of the traveling wave tube are guaranteed, the influence of low-voltage discharge on the business continuity of the satellite payload system is avoided, and the reliability of the satellite payload system is improved.

[0080] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A potting mold for a traveling wave tube, characterized in that: Including a mold substrate and a film layer structure; The mold base is a hollow tubular structure, the inner cavity of which is a potting channel, one end of the mold base is plug-connected to the traveling wave tube, and the other end of the mold base is an injection end; The tube wall of the mold base is provided with at least one opening, the opening is communicated with the potting channel, and the film layer structure covers the opening; The membrane structure can allow water vapor and air to pass into the potting channel, so that water molecules act on the potting material in the potting channel, thereby improving the curing speed and uniformity of the potting material.

2. The potting mold for a traveling wave tube according to claim 1, characterized in that: The film layer structure is adhered and fixed to the inner wall of the mold base.

3. The potting mold for a traveling wave tube according to claim 1, characterized in that: The shape of the opening is one or more of circular, rectangular, and elliptical.

4. The potting mold for a traveling wave tube according to claim 1, characterized in that: A plurality of openings are evenly distributed on the tube wall of the mold base and are arranged around the central axis of the mold base.

5. The potting mold for a traveling wave tube according to claim 1, characterized in that: The area of ​​a single opening ranges from 3-300mm 2 The areas of the openings formed on the tube wall of the mold base may be the same or different.

6. The potting mold for a traveling wave tube according to claim 1, characterized in that: The number of openings formed on the tube wall of the mold base is in the range of 1 to 100, and each opening is covered with a film layer structure.

7. The potting mold for a traveling wave tube according to claim 1, characterized in that: The membrane layer structure is made of nylon woven material, polyester fiber fabric or microporous polytetrafluoroethylene.

8. A mold preparation method for preparing a potting mold for a traveling wave tube as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: making a mold base according to the size of the part of the traveling wave tube to be potted; Step 2, opening a hole in the tube wall of the mold base; Step 3: Select a waterproof and breathable membrane as the membrane layer structure according to the size of the openings, and ensure that each opening is covered by the membrane layer structure; Step 4: clean the mold base and bond the film structure to the inner side of the mold base by bonding material.

9. A potting method, using the potting mold for a traveling wave tube according to any one of claims 1 to 7 to pot the electrode terminal of a traveling wave tube, characterized in that: The following steps are involved: Step 1: plug and connect the mold base to the electrode terminal of the traveling wave tube; Step 2, leading the wire connected to the electrode terminal of the traveling wave tube out from the injection end of the mold base; Step 3, injecting the potting material into the potting channel from the injection end of the mold base; Step 4: Wait for the potting material to cure in a curing environment, remove the potting mold, and the potting is completed.

10. The potting method according to claim 9, characterized in that: The curing environment is: Temperature 20℃-80℃, humidity 20%-50%; The curing time is 8-96h.

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