A high-voltage corona-proof potting method for electrical connectors suitable for aerospace applications

Abstract

The present invention provides an anti-high-voltage corona potting method for an electrical connector suitable for aerospace applications, characterized in that it includes the following steps: after welding the electrical connector, potting is performed on the welding surface using room temperature curing silicone rubber treated with vacuum degassing, uniformly covering the welding surface, the silicone rubber liquid surface completely covers and protects the welding points, and the insulation skin port at the root of the wire is submerged, the silicone rubber is fully allowed to stand and solidify, and the surface of the potting layer is trimmed; the electrical connector is potted with a second layer of epoxy glue treated with vacuum degassing on the base of the first layer of silicone rubber potting layer, uniformly covering the silicone rubber potting layer and covering the root of the wire lead-out line, the epoxy glue is fully allowed to stand and solidify, and the surface of the potting layer is trimmed. The secondary anti-corona potting method of the present invention has the characteristics of high reliability of solder joints, strong reworkability, strong anti-corona protection performance, etc., which significantly improves the quality and reliability of the anti-corona method of the electrical connector, and is therefore of great significance.

Description

Technical Field

[0001] The invention relates to a high-voltage corona-proof potting method for an electric connector suitable for aerospace applications. Background Art

[0002] The potting of electrical connectors is a conventional electronic assembly process technology. The principle is to effectively achieve the effect of waterproofing and preventing metal chips and other unnecessary objects by potting glue materials at the tail of the electrical connector.

[0003] The principle of high-voltage corona protection technology is to control air concentration and humidity, improve dielectric insulation coefficient, etc., to effectively prevent local discharge on the surface of charged bodies in gas or liquid media. At present, the high-voltage corona protection capabilities of electrical connectors in the industry widely rely on increasing structural spacing, selecting good anti-corona materials, and relying on targeted design of electrical connectors to obtain better high-voltage corona resistance of the electrical connectors themselves. This method is not universally applicable and cannot provide effective technical support for conventional non-high-voltage resistant electrical connectors. At the same time, the industry lacks necessary research on high-voltage corona protection technology during the use of conventional non-high-voltage resistant electrical connectors.

[0004] In the prior art, the protection of electrical connectors against corona is generally achieved through the selection of electrical connectors, insulating sleeves or resin-based hard glue potting of connectors. However, when the requirements for the carrying current of the wires and the number of wires are clear, there is often a problem that there are no suitable anti-corona specifications and types of electrical connectors to choose from. In extreme service conditions such as aerospace applications, the air pressure changes in the electrical connectors, making it easier for the thin air medium to be broken down, greatly increasing the difficulty of corona protection. The traditional method of increasing the creepage distance with insulating sleeves cannot ensure the realization of high-voltage corona protection. Although the method of hard glue potting can effectively achieve corona protection for electrical connectors, this prior art method determines that the solder joints of the electrical connectors cannot be repaired, and the solder joints are prone to stress concentration due to drastic changes in volume due to the mismatch of thermal expansion coefficients during the hard glue solidification process and in the use environment, which makes it very easy for solder joint failures to occur and electrical connections to fail. The solder joints touching the hard glue are essentially a more serious category of prohibited or restricted process methods, and there are a large number of potential failure hazards.

[0005] In the field of electronic assembly, high-voltage and anti-corona technology is implemented for conventional electrical connectors. A soft adhesive layer is formed by silicone rubber potting to protect solder joints and wire cores, avoiding stress concentration caused by factors such as solidification of potting materials such as epoxy glue and volume changes during service, mismatch of thermal expansion coefficients, etc., thereby improving solder joint reliability and preventing solder joint creep failure due to stress. A dense adhesive layer is formed by potting epoxy glue at the wire bundle to improve the barrier effect between the exposed metal part and the air medium, overcoming defects such as peeling off of the soft adhesive layer such as silicone rubber potting layer and the wire insulation layer caused by wire disturbance during the service of the electrical connector, and maintaining the reworkability of the electrical connector, completing high-quality and reliable high-voltage corona potting. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for anti-high-voltage corona potting of an electrical connector suitable for aerospace applications, characterized in that it comprises the following steps:

[0007] After the electrical connector is welded, the welding surface is encapsulated with room temperature curing silicone rubber that has been vacuum degassing, evenly covering the welding surface. The silicone rubber liquid surface completely covers and protects the welding points, and covers the insulation skin port at the root of the wire. The silicone rubber is fully allowed to stand and cure, and the surface of the encapsulation layer is trimmed;

[0008] The electrical connector is potted with a second layer of epoxy glue treated with vacuum degassing on the base of the first layer of silicone rubber potting layer, evenly covering the silicone rubber potting layer and enveloping the root of the lead wire. The epoxy glue is fully allowed to stand and solidify, and the surface of the potting layer is trimmed.

[0009] Furthermore, the surface of the encapsulation layer is trimmed by using tools such as chip-retaining pliers to trim the surface of the encapsulation layer to remove sharp edges and pointed parts.

[0010] Furthermore, the vacuum degassing treatment removes air in the silicone rubber or epoxy adhesive to prevent the formation of bubble defects.

[0011] Furthermore, the contact area between the welding surface of the electrical connector and the welding point is a silicone rubber potting layer.

[0012] Furthermore, the height h of the silicone rubber potting layer of the electrical connector above the port of the wire insulation layer is 3 to 5 mm.

[0013] Furthermore, on the base of the silicone rubber encapsulation layer, the second encapsulation layer made of epoxy adhesive at the part in contact with the wire has a thickness of 3 to 5 mm.

[0014] Furthermore, the silicone rubber is a single-component room temperature curing silicone rubber or a two-component curing silicone rubber.

[0015] Furthermore, the one-component room temperature curing silicone rubber is any one selected from D04 of Shanghai Rubber Products Research Institute and GD414 of Zhonglan Chenguang, and the two-component curing silicone rubber is any one selected from GT-4 of Shanghai Rubber Products Co., Ltd. and QD231 of Beijing Chemical No. 2 Co., Ltd.

[0016] Furthermore, the epoxy adhesive is a two-component epoxy adhesive.

[0017] Furthermore, the epoxy adhesive is any one selected from EC104 of Emerson & Cuming and 2651MM of Loctite.

[0018] The secondary anti-corona potting method of the present invention has the characteristics of high reliability of solder joints, strong reworkability, strong anti-corona protection performance, etc., which significantly improves the quality and reliability of the anti-corona method of electrical connectors, and is therefore of great significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a primary potting according to an embodiment of the present invention;

[0020] Figure 2 It is a schematic diagram of secondary potting according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] The purpose of the present invention is to provide an anti-high-voltage corona potting method for electrical connectors suitable for aerospace applications, which can solve the problems of poor long-term service reliability of solder joints and non-repairability of solder joints in traditional anti-corona methods for electrical connectors. At the same time, in the space service environment, the thin air medium is further easily broken down, and the difficulty of anti-corona is greatly increased, which poses a severe challenge to the anti-corona requirements and control methods. The present invention effectively solves the problem of low-pressure corona protection in the space application environment.

[0023] The present invention adopts a technical method of two-layer encapsulation of heterogeneous materials to realize high-voltage corona protection technical treatment for the electrical connector.

[0024] Specifically, the anti-high-voltage corona potting method of the electrical connector suitable for aerospace applications of the present invention comprises: after the electrical connector is welded, the first layer of soft potting glue is subjected to vacuum degassing treatment to remove the air in the glue liquid and prevent the formation of bubble defects. The silicone rubber is used for potting on the welding surface to evenly cover the welding surface, and the glue liquid surface completely covers and protects the welding point, and the insulation skin port at the root of the wire is not covered; thus, the contact part between the welding surface of the electrical connector and the welding point is the silicone rubber potting layer. The height h of the silicone rubber potting layer of the electrical connector over the insulation layer port of the wire is about 3 to 5 mm; the silicone rubber can be a single-component room temperature curing silicone rubber such as D04 of Shanghai Rubber Products Research Institute, GD414 of Zhonglan Chenguang, and a two-component curing silicone rubber such as GT-4 of Shanghai Rubber Products Co., Ltd. and QD231 of Beijing Chemical No. 2 Co., Ltd. The glue liquid is fully left to stand and solidify, and the wire and the colloid must not be relatively deformed during the curing period to prevent the interface between the wire insulation layer and the glue layer from separating. Use tools such as chip-retaining pliers to trim the surface of the potting layer, remove sharp edges, sharp points and other parts, and the potting layer should be smooth and free of defects such as large bubbles. Perform vacuum degassing on the epoxy glue to remove the air in the secondary glue to prevent the formation of bubble defects. The electrical connector is placed on the base of the first potting layer, and the secondary glue is used to perform the second potting, evenly covering the potting layer and covering the root of the lead wire; on the base of the silicone rubber potting layer, the second potting layer is prepared with epoxy glue at the contact part with the wire, and the thickness is about 3 to 5 mm; the epoxy glue used for the secondary potting glue potting can be two-component epoxy glue such as EC104 of Emerson & Cuming and 2651MM of Loctite. The secondary glue is fully allowed to stand and solidify. Use tools such as chip-retaining pliers to trim the surface of the potting layer, remove sharp edges, sharp points and other parts, and the potting layer should be smooth and free of defects such as large bubbles.

[0025] Compared with the traditional electronic assembly potting method, the two-step potting method of epoxy glue based on silicone rubber has the characteristics of solder joint anti-corona, long-term reliable service of solder joints, excellent potting performance, and reworkability of electrical connectors. Eliminating the adverse effects of hard anti-corona materials on solder joints is of great significance for electrical connectors with anti-corona service requirements.

[0026] The secondary potting method of the present invention can effectively solve the problem of corona protection of electrical connector solder joints in space applications. The first potting glue in this method is soft glue. On the one hand, it plays the role of covering and protecting the solder joints, isolating the resin hard glue, and eliminating the stress concentration of the solder joints due to drastic volume changes caused by the mismatch of thermal expansion coefficients during the hard glue solidification process and the use environment. On the other hand, the soft glue coating of the solder joints greatly improves the reworkability of the solder joints. After the resin glue is cured, rework requires the use of destructive external force, causing secondary stress damage to the solder joints of a large number of electrical connectors.

[0027] Figure 1 This is a schematic diagram of a primary potting according to an embodiment of the present invention; Figure 2 Schematic diagram of secondary encapsulation according to an embodiment of the present invention. Figures 1-2 As shown, the present invention provides a high-voltage corona-proof potting method for an electrical connector suitable for aerospace applications, comprising:

[0028] Step S1, after the electrical connector 1 is welded, the first layer of soft potting glue is subjected to vacuum degassing treatment to remove air in the glue to prevent the formation of bubble defects;

[0029] Step S2, the silicone rubber 2 is used to potting on the welding surface, evenly covering the welding surface, and the glue liquid surface completely covers and protects the welding point, and submerges the insulation skin port 3 at the root of the wire 4;

[0030] Step S3, the glue is allowed to stand and solidify fully, and during the solidification period, the wire 4 and the glue should not be deformed relative to each other to prevent the insulation layer of the wire 4 from separating from the interface of the glue layer;

[0031] Step S4, trimming the surface of the potting layer using tools such as chip-retaining pliers to remove sharp edges, sharp points, etc. The potting layer should be smooth and free of defects such as large bubbles;

[0032] Step S5, performing vacuum degassing treatment on the epoxy glue 5 to remove the air in the secondary glue solution to prevent the formation of bubble defects;

[0033] Step S6, placing the electrical connector 1 on the base of the first potting layer, using the secondary glue to perform a second potting, uniformly covering the potting layer and encapsulating the root of the lead wire 4;

[0034] Step S7, the secondary glue is allowed to stand and solidify fully; during the solidification period, the wire 4 and the colloid must not be deformed relative to each other, so as to prevent the insulation layer of the wire 4 and the interface of the glue layer from separating and deforming;

[0035] Step S8, the surface of the potting layer is trimmed with tools such as chip-retaining pliers to remove sharp edges, sharp points and other parts. The potting layer should be smooth and free of defects such as large bubbles. The anti-corona electronic assembly potting of the electrical connector 1 is completed.

[0036] The anti-high-voltage corona potting method of the electric connector suitable for aerospace applications of the present invention forms a first layer of potting protection by potting silicone rubber at the welding cup of the electric connector, wrapping the welding point and then standing to solidify. On the base glue of the first layer of potting protection, epoxy glue is further potted to cover the silicone rubber potting layer and wrap the root of the lead wire of the electric connector to form a second field potting protection, thereby realizing the anti-high-voltage corona potting treatment of the electric connector. By adjusting the thickness of the first layer of potting silicone rubber, the stress effect of the mismatch of the thermal expansion coefficient of the welding point boundary of different types of electric connectors is protected during the service of the product, and by adjusting the thickness of the second layer of epoxy glue, the anti-high-voltage corona function of the electric connector under different voltage conditions is realized. The potting method can solve the problems of poor long-term service reliability of welding points and non-repairability of welding points of electric connectors in traditional anti-corona methods of electric connectors. At the same time, in the space service environment, the thin air medium is further easily broken down, the difficulty of anti-corona is greatly increased, and severe challenges are posed to the anti-corona requirements and control methods. The present invention effectively solves the problem that low air pressure in the space application environment makes corona more likely to occur.

[0037] The embodiments in this specification are described in a progressive manner, and the embodiments focus on the differences from other embodiments. The same or similar parts between the embodiments can be referenced to each other.

[0038] Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A method for anti-high-voltage corona potting of electrical connectors suitable for aerospace applications, characterized in that: The steps include: After the electrical connector is welded, the welding surface is potted with room temperature curing silicone rubber that has been vacuum degassing treated to evenly cover the welding surface. The silicone rubber liquid surface completely covers and protects the welding point and submerges the insulation skin port at the root of the wire. The silicone rubber is fully allowed to stand and cure, and the surface of the potting layer is trimmed. The contact area between the welding surface of the electrical connector and the welding point is the silicone rubber potting layer. The height h of the electrical connector silicone rubber potting layer submerging the insulation layer port of the wire is 3~5mm; The electrical connector is potted with a second layer of epoxy glue that has been subjected to vacuum degassing on the base of the first layer of silicone rubber potting layer, uniformly covering the silicone rubber potting layer and enveloping the root of the lead wire. The epoxy glue is allowed to stand and fully solidify, and the surface of the potting layer is trimmed. The thickness of the second potting layer prepared with epoxy glue on the base of the silicone rubber potting layer at the part in contact with the wire is 3 to 5 mm.

2. The method for anti-high-voltage corona potting of an electrical connector suitable for aerospace applications according to claim 1, characterized in that: The trimming of the surface of the encapsulation layer is to trim the surface of the encapsulation layer with chip-retaining pliers to remove sharp edges and pointed parts.

3. The method for high-voltage corona protection of electrical connectors suitable for aerospace applications according to claim 1, characterized in that: During the vacuum degassing process, air in the silicone rubber or epoxy adhesive is removed to prevent the formation of bubble defects.

4. The method for anti-high-voltage corona potting of an electrical connector suitable for aerospace applications according to claim 1, characterized in that: The silicone rubber is a single-component room temperature curing silicone rubber or a two-component curing silicone rubber.

5. The method for high-voltage corona protection of electrical connectors suitable for aerospace applications according to claim 4, characterized in that: The one-component room temperature curing silicone rubber is GD414 produced by Zhonglan Chenguang, and the two-component curing silicone rubber is QD231 produced by Beijing Chemical No. 2 Co., Ltd.

6. The method for high-voltage corona protection of electrical connectors suitable for aerospace applications according to claim 1, characterized in that: The epoxy adhesive is a two-component epoxy adhesive.

7. The method for high-voltage corona protection of an electrical connector suitable for aerospace applications according to claim 6, characterized in that: The epoxy adhesive is 2651MM from Loctite.

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