High-temperature-resistant electric connector and preparation method thereof

Abstract

The invention provides a high-temperature-resistant electric connector and a preparation method thereof, and relates to the technical field of electric connectors. The high-temperature-resistant electric connector comprises a contact body, an insulator, a shell and a split ring structure, the split ring structure is arranged between the insulator and the shell, the split ring structure comprises an annular side wall and a base connected to one axial end of the annular side wall, the base and the annular side wall define a cavity used for containing the insulator, a notch is formed in the annular side wall, and the insulator is arranged in the cavity. The notch extends in the axial direction of the annular side wall, and one end of the notch communicates with the opening of the cavity. The split ring structure is additionally arranged between the insulator and the shell, sealing connection between the insulator, the contact body and the split ring structure is achieved through brazing, internal stress concentration during service of the insulator and the shell is remarkably reduced, and the sealing reliability between the insulator and the shell in the electric connector at the high temperature is improved; and the sealing performance of the product can meet the actual use requirement.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical connectors, and in particular to a high temperature resistant electrical connector and a preparation method thereof. Background Art

[0002] High temperature resistant electrical connectors are widely used in electrical equipment and systems in various high temperature environments, such as aerospace, military equipment, power equipment, petrochemical and other fields, for connecting and accurately transmitting electrical signals, power and data. A significant problem with electrical connectors is the thermal environment problem. In some special cases, some electromechanical components need to be exposed. For example, the electrical connector used for separation between aircraft stages. After separation, the exposed part that moves with the aircraft will be subjected to long-term high temperature, and the ambient temperature will reach 800℃ or even more than 1,000 degrees Celsius. During the use of electrical connectors, external high temperature flames, heat flow and other environments will damage the exposed parts of the electrical connectors, which may cause problems such as the fragmentation of insulation materials and failure of thermal protection. The high temperature fragments, dust and other waste materials that are generated enter the interior of the electrical connector, which will damage the wiring harness, mechanism, etc. In severe cases, it may cause accidents such as electrical short circuit and combustion, which has a significant impact. Therefore, for high temperature resistant electrical connectors, how to achieve interface sealing in a high temperature environment and isolate the influence of external high temperature and waste materials is an important problem that needs to be solved.

[0003] Electrical connectors are generally composed of three basic units: a shell, an insulator, and a contact body (a general term for pins and sockets). Glass sealing is usually used to seal the shell, contact body, and insulator, that is, glass is infiltrated between the shell, contact body, and insulator. This is because the glass sealing preparation method is relatively simple and convenient, and the maximum operating temperature can reach 485°C. However, in extremely high temperature environments, glass-sealed products will generate internal stress inside the electrical connector due to the mismatch in thermal expansion coefficients between the insulator and the shell, which will cause the connector to become loose, deformed, or broken inside the connector seal, causing the connector to fail. Summary of the invention

[0004] The problem solved by the present invention is that the current electrical connector has insufficient sealing performance under extremely high temperatures and cannot be used under extremely high temperatures.

[0005] In order to solve the above problems, the present invention provides a high temperature resistant electrical connector and a preparation method thereof.

[0006] In the first aspect, the present invention provides a high-temperature resistant electrical connector, comprising a contact body, an insulator, a shell and an open ring structure, wherein the insulator is sleeved on the contact body, and the shell is sleeved on the outside of the insulator; the open ring structure is arranged between the insulator and the shell, and the open ring structure comprises an annular side wall and a base connected to one axial end of the annular side wall, the base and the annular side wall form a cavity for accommodating the insulator, and a notch is arranged on the annular side wall, the notch extends along the axial direction of the annular side wall and one end of the notch is connected to the opening of the cavity.

[0007] Optionally, there are multiple notches, and the multiple notches are evenly arranged along the circumference of the annular side wall.

[0008] Optionally, the vertical cross-section of the notch is rectangular; and / or the other end of the notch extends to the connection between the annular side wall and the base.

[0009] Optionally, the material of the open ring structure is the same as that of the outer shell.

[0010] Optionally, the open ring structure and the shell are both made of stainless steel, and the insulator is made of ceramic.

[0011] In a second aspect, the present invention provides a method for preparing a high temperature resistant electrical connector, which is used to prepare the high temperature resistant electrical connector as described above, comprising:

[0012] Processing the ceramic material into a cylindrical shape to obtain an insulator;

[0013] Assembling the insulator, the contact body and the open ring structure together, and brazing them to obtain a brazed assembly;

[0014] The brazing assembly is assembled with the housing and laser welded to obtain a high temperature resistant electrical connector.

[0015] Optionally, the method for preparing the high temperature resistant electrical connector further comprises: performing moisture-proof treatment on the structure after laser welding.

[0016] Optionally, the moisture-proof treatment of the laser-welded structure includes:

[0017] After grinding, cleaning and drying the surface of the laser welded structure, it is immersed in the SiO2 dispersion system under vacuum;

[0018] The impregnated structure is dried at a controlled temperature and then sintered;

[0019] The surface of the sintered structure is polished.

[0020] Optionally, the SiO2 dispersion system includes silica sol and micron-sized quartz powder mixed in a preset ratio.

[0021] Optionally, the method for preparing the ceramic material comprises:

[0022] S1, uniformly mixing 30%-80% of ceramic powder, 5%-50% of ceramic precursor, and 1%-20% of sintering aid by volume to obtain a first mixed powder;

[0023] S2, placing the first mixed powder in an inert atmosphere or a first reducing atmosphere for heat treatment;

[0024] S3, mixing 30% of the first mixed powder after S2 with 70% of the solvent to obtain a ceramic slurry;

[0025] S4, dissolving a boron nitride precursor in deionized water to form a saturated solution, and adding the saturated solution dropwise into the ceramic slurry to obtain a mixed slurry;

[0026] S5, drying the mixed slurry to obtain a second mixed powder;

[0027] S6, heat-treating the second mixed powder under a second reducing atmosphere to obtain a modified ceramic powder;

[0028] S7, forming the modified ceramic powder and then sintering it to obtain the ceramic material.

[0029] The beneficial effects of the high temperature resistant electrical connector of the present invention are:

[0030] The present invention adds an open ring structure between the insulator and the shell, and adopts solder brazing to achieve a sealed connection between the insulator, the contact body and the open ring. The use temperature of the solder is higher than that of glass. During brazing, the opening is used to release the internal stress generated inside the high-temperature resistant electric connector due to the mismatch of the thermal expansion coefficients of the insulator and the shell, thereby significantly reducing the internal stress concentration of the insulator and the shell during service, improving the sealing reliability between the insulator and the shell in the high-temperature resistant electric connector under high temperature, making the sealing performance of the product meet the actual use requirements, and solving the problem that the internal stress concentration inside the high-temperature resistant electric connector under extremely high temperature environment causes the connector sealing part to become loose, deformed or broken, thereby causing the connector to fail. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of a high temperature resistant electrical connector in an embodiment of the present invention;

[0032] Figure 2 for Figure 1 A cross-sectional view of a medium-high temperature resistant electrical connector along the AA direction;

[0033] Figure 3 is a schematic diagram of the overall structure of an insulator in an embodiment of the present invention;

[0034] Figure 4 for Figure 3 A top view of the middle insulator;

[0035] Figure 5 It is a schematic diagram of the overall structure of the open ring structure in an embodiment of the present invention;

[0036] Figure 6 for Figure 5 A top view of the middle split ring structure;

[0037] Figure 7 This is a schematic diagram of the overall structure of the housing in an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the assembly structure of the open ring structure and the insulator in Example 1 of the present invention;

[0039] Fig. 9 This is a schematic diagram of the assembly structure of the housing and the insulator in Comparative Example 1 of the present invention;

[0040] Fig.10 The stress distribution at the interface between the ceramic insulator and the stainless steel open ring structure in Example 1 of the present invention when in service;

[0041] Fig.11 This is the stress distribution at the interface between the ceramic insulator and the stainless steel housing in comparative example 1 of the present invention when in service.

[0042] Description of reference numerals:

[0043] 1. Contact body; 2. Insulator; 21. Hole structure; 3. Open ring structure; 31. Base; 32. Annular side wall; 33. Notch; 4. Shell. DETAILED DESCRIPTION

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0045] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application;

[0046] The term "including" and its variations used in this article are open inclusions, that is, "including but not limited to"; the term "based on" is "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, the meaning of "multiple" is two or more.

[0047] The electrical connector is composed of a housing, an insulator, a contact (a general term for pins and sockets), etc. Among them, the insulator is used to keep the pins and sockets in the set position, and to electrically insulate each contact and each contact from the housing, so as to effectively isolate the current and prevent arc discharge. Since pins or sockets need to be set on the insulator, in order to facilitate processing, the insulator is mostly made of polymers and molded using thermosetting plastics. However, the operating temperature range of polymers is only -65°C to 350°C. In extreme environments with higher temperatures, the insulation performance drops sharply, and in the case of an instantaneous increase in temperature, the polymer will deform and fail, and cannot meet the use requirements of electrical connectors at high temperatures. For example, the insulating dielectric materials of some commonly used electrical connectors cannot work normally in extremely high temperature environments of 800°C or even thousands of degrees, and the high temperature resistance is insufficient. For insulators of electrical connectors that withstand temperatures above 800°C, special insulating materials with better temperature resistance, such as composite materials, can be used. They can maintain certain insulation properties at high temperatures. For example, ceramic materials can maintain high insulation properties at high temperatures. Therefore, the insulators of electrical connectors that serve at temperatures above 800°C are usually made of ceramic materials.

[0048] In addition, in the field of electrical connectors, stainless steel is generally used as the shell material because compared with other metals such as brass, stainless steel is more durable and has higher corrosion resistance, mechanical strength, and high plasticity. Therefore, the shell is usually made of stainless steel.

[0049] However, there is a big difference in thermal expansion coefficient between ceramic and stainless steel. Ceramic is a non-metallic material with a very small thermal expansion coefficient. According to statistics, the thermal expansion coefficient of ceramic is about 5×10 -6 / ℃-7×10 -6 / ℃. Stainless steel is a metal material with a high thermal expansion coefficient of about 17×10 -6 / ℃-19×10 -6 / ℃.

[0050] Therefore, in the related art, there is a problem that internal stress is generated inside the electrical connector due to the mismatch in thermal expansion coefficients between the insulator 2 and the metal shell 4, which in turn causes loosening, deformation or breakage inside the connector seal, causing connector failure, making it impossible to guarantee the sealing performance of the electrical connector.

[0051] In view of the problems existing in the above-mentioned related technologies, this embodiment provides a high temperature resistant electrical connector and a preparation method thereof.

[0052] like Figure 1 , Figure 2 As shown, a high temperature resistant electrical connector provided by an embodiment of the present invention includes: a contact body 1, an insulator 2, a shell 4 and an open ring structure 3, wherein the insulator 2 is sleeved on the contact body 1, and the shell 4 is sleeved on the outside of the insulator 2; the open ring structure 3 is arranged between the insulator 2 and the shell 4, and the open ring structure 3 includes an annular side wall 32 and a base 31 connected to one axial end of the annular side wall, the base 31 and the annular side wall 32 form a cavity for accommodating the insulator 2, and a notch 33 is arranged on the annular side wall 32, and the notch 33 extends along the axial direction of the annular side wall 32 and one end is connected to the opening of the cavity.

[0053] In this embodiment, the high temperature resistant electrical connector includes an insulator 2 ( Figure 3 , Figure 4 )、Open ring structure 3( Figure 5 , Figure 6 ) and housing 4( Figure 7), one end of the open ring structure 3 is a base 31 for supporting the insulator 2, the open ring structure 3 has a cavity formed by the annular side wall 32 and the base 31, the other end of the open ring structure 3 is the opening of the cavity, the cavity is used to set the insulator 2, and the annular side wall 32 is provided with a notch 33 connected to the opening, so that when the insulator 2 and the shell 4 are packaged, the mature and commonly used welding technology can be used to replace the glass sealing method, because the notch 33 of the open ring structure 3 can provide a release space for the solder during welding, thereby avoiding the solder extrusion when the weld shrinks to produce a large compressive stress on the insulator 2, which will be further explained below. Among them, brazing is a welding method that uses liquid brazing filler metal to fill the gap of solid workpieces to connect metals. Since it has little effect on the physical and chemical properties of the parent material, it is a commonly used welding method, so brazing is preferred.

[0054] However, if there is no open ring structure 3, the ceramic insulator 2 and the stainless steel shell 4 are directly brazed or glass welded. Since the expansion coefficient of the stainless steel shell 4 is higher than that of the ceramic insulator 2, under the high temperature conditions of welding, the stainless steel shell 4 is prone to thermal expansion, that is, the stainless steel shell 4 is greatly deformed, thereby increasing the welding gap between the stainless steel shell 4 and the insulator 2. The increase in the welding gap makes it easier for the molten solder or glass to flow into the gap, resulting in more solder or glass flowing into the weld. In this way, when cooling after welding, the stainless steel shell 4 will shrink. It can be understood that steel will undergo thermal expansion at high temperatures and shrink after cooling. However, since the thermal expansion coefficient of steel is large and the shrinkage process is relatively slow, the steel cannot completely recover to its original size after cooling, and will only shrink slightly, that is, the steel cannot completely recover to its original shape after cooling. This is determined by the physical property of the large thermal expansion coefficient of steel. The shrinkage of the stainless steel shell 4 will cause the welding gap between the stainless steel shell 4 and the insulator 2 to shrink. At this time, since a lot of solder or glass has flowed into the gap during the previous high-temperature welding process, the gap will be filled with solder or glass after the gap shrinks, and the internal molecular gap of the solder or glass will be reduced, which will produce greater compressive stress on the ceramic.

[0055] After the open ring structure 3 is set in this embodiment, the insulator 2 and the open ring structure 3 are welded. It can be understood that the open ring structure 3 is made of metal. For example, since the insulator 2 is usually made of ceramic material and the shell 4 is made of stainless steel, the open ring structure 3 is preferably made of the same material as the shell 4. In this way, when the open ring structure 3 and the shell 4 are welded, the two are homogeneous materials, which is conducive to welding. Therefore, the material of the open ring structure 3 is also preferably stainless steel. Since the expansion coefficient of the metal material (stainless steel) is higher than that of ceramic, the open ring structure 3 made of stainless steel is also prone to thermal expansion at high temperatures and undergoes large deformation, which increases the welding gap between the open ring structure 3 and the insulator 2, and then causes the molten solder to flow into the gap. When cooling after welding, the open ring structure 3 made of stainless steel will also shrink, thereby shrinking the welding gap between the insulator 2 and the open ring structure 3. However, unlike the aforementioned situation where the open ring structure 3 is not provided, at this time, the solder or glass filling the welding gap between the insulator 2 and the open ring structure 2 will flow to the notch 33, and the solder or glass will be concentrated at the notch 33, thereby releasing the stress at the notch 33. Because the excess solder or glass is dispersed to the notch 33, the molecular spacing of the solder or glass in the welding gap between the insulator 2 and the open ring structure 3 does not decrease. Therefore, after the welding is cooled, the shrinkage of the open ring structure 3 greatly reduces the increase in compressive stress on the ceramic insulator 2, thereby avoiding damage to the ceramic insulator 2.

[0056] Therefore, this embodiment adds an open ring structure 3 between the insulator 2 and the shell 4, and uses the gap 33 of the open ring structure 3 to release the internal stress generated inside the high temperature resistant electrical connector due to the mismatch of thermal expansion coefficients between the insulator 2 and the shell 4. It can be understood that when the insulator 2 and the shell 4 are directly welded, the internal stress between the insulator 2 and the shell 4 is relatively concentrated due to the thermal expansion and contraction deformation of the shell 4. After the open ring structure 3 is added between the insulator 2 and the shell 4, the open ring structure 3 and the insulator 2 are first welded, and the notch 33 on the open ring structure 3 is used to alleviate the stress concentration between the open ring structure 3 and the insulator 2 caused by the shrinkage and deformation of the open ring structure 3, thereby reducing the stress between the open ring structure 3 and the insulator 2. Then, the open ring structure 3 and the shell 4 are welded, and the high temperature during welding will cause the solder at the notch 33 to melt and deform, and the deformed solder will release stress, so that the stress at the notch 33 can be further released, thereby significantly reducing the internal stress concentration between the insulator 2 and the shell 4 when they are in service, and improving the sealing reliability between the insulator 2 and the shell 4 in the high temperature resistant electrical connector under high temperature, so that the sealing performance of the product meets the actual use requirements, and solves the problem that the thermal expansion coefficient of the insulator 2 and the metal shell 4 does not match in an extremely high temperature environment, resulting in internal stress inside the high temperature resistant electrical connector, which in turn causes the connector to loosen, deform or break at the sealing point, and the connector fails.

[0057] Optionally, there are multiple notches 33 , and the multiple notches 33 are evenly arranged along the circumference of the annular side wall 32 .

[0058] In this optional embodiment, a plurality of notches 33 are provided along the circumference of the annular side wall 32, and each notch 33 extends in a direction parallel to the axial direction of the annular side wall 32. Thus, when the insulator 2 and the shell 4 are sealed by welding, uniform stress release can be performed along the circumference of the insulator 2, thereby avoiding adverse effects caused by stress concentration.

[0059] Optionally, the vertical cross-section of the notch 33 is rectangular.

[0060] The so-called vertical section refers to the section of the notch 33 in the longitudinal direction, and the longitudinal direction is a direction parallel to the axial direction of the annular side wall 32. The vertical section of the notch 33 is designed to be rectangular, that is, the notch 33 is a notch of uniform size along the direction parallel to the axial direction of the annular side wall 32, so that uniform stress release can be performed to avoid stress concentration on the wall.

[0061] Optionally, the other end of the notch 33 extends to the connection between the annular side wall 32 and the base 31. That is, the notch 33 axially penetrates the entire annular side wall 32, so that the notch 33 can be used to more effectively release the profit caused by the shrinkage and deformation of the open ring structure 3, and can better avoid the stress concentration between the open ring structure 3 and the insulator 2.

[0062] Optionally, the material of the open ring structure 3 is the same as that of the shell 4. In this way, the open ring structure 3 and the shell 4 are welded with the same material, and there is no problem of interface reaction, intermediate layer or inclusions, which can ensure good connection quality and welding stability.

[0063] Optionally, the materials of the open ring structure 3 and the shell 4 are both stainless steel, and the material of the insulator 2 is ceramic. As described above, ceramic materials can maintain high insulation performance at high temperatures, so the insulator 2 is preferably made of ceramic materials. Stainless steel materials have advantages such as good corrosion resistance and high mechanical strength, so the open ring structure 3 and the shell 4 are preferably made of stainless steel.

[0064] An embodiment of the present invention provides a method for preparing a high temperature resistant electrical connector, which is used to prepare the high temperature resistant electrical connector as described above. The method comprises:

[0065] Processing the ceramic material into a cylindrical shape to obtain an insulator 2;

[0066] Assembling the insulator 2, the contact body 1 and the open ring structure 3 together, and brazing them to obtain a brazed assembly;

[0067] The brazing assembly is assembled with the housing 4 and laser welded to obtain a high temperature resistant electrical connector.

[0068] In this embodiment, the insulator 2 is first processed into a cylindrical shape using a ceramic material to facilitate assembly of the contact body 1. Figure 3 , Figure 4As shown. Then, an open ring structure 3 is added between the insulator 2 and the shell 4. During the preparation process, the insulator 2 and the open ring structure 3 are first assembled and connected, and then the open ring structure 3 and the shell 4 are assembled and connected. The insulator 2 and the open ring structure 3 are connected by brazing. This is because, compared with other welding methods, brazing will not cause embrittlement and discoloration of the metal, and can ensure the original state of the welded parts. In addition, due to the notch 33 provided on the open ring structure 3, the excessive solder flowing into the weld during the brazing process can flow to the notch 33, reducing stress concentration or excessive damage to the insulator 2, such as the breakage or fracturing of the insulator 2, which helps to improve the reliability of the high temperature resistant electrical connector. In addition, laser welding is adopted between the open ring structure 3 and the outer shell 4. Therefore, although stress is concentrated at the notch 33 of the open ring structure 3, the high temperature during welding will melt the solder flowing into the notch 33, and the solder will deform during the melting process, thereby further releasing the stress. At the same time, laser welding is a non-contact welding method that does not require pressurization of the material. It has the advantages of lower welding cost, lower material waste rate, and easy automated welding. Moreover, since laser welding can realize automatic welding, it also has the characteristics of high processing precision and high welding efficiency.

[0069] The preparation method of this embodiment realizes the connection between the insulator 2 and the open ring structure 3 by brazing. The internal stress of the open ring structure 3 is relatively small, and a large stress exists only at the notch 33. By welding the open ring structure 3 and the outer shell 4, the stress concentration at the notch 33 is further released, thereby effectively alleviating the stress concentration generated when serving under high temperature, and avoiding the problem of loosening, deformation or fracture inside the connector seal.

[0070] Optionally, the preparation method further comprises: assembling a pin or a socket on the insulator 2. This is a prior art and will not be described in detail here.

[0071] Optionally, the preparation method further comprises: performing moisture-proof treatment on the structure after laser welding.

[0072] In this optional embodiment, after the brazed components are assembled with the housing 4 by laser welding, the obtained structure is subjected to moisture-proof and waterproof treatment to reduce the adverse effects of water absorption on the insulation performance of the structure.

[0073] Optionally, the moisture-proof treatment of the laser-welded structure includes:

[0074] After grinding, cleaning and drying the surface of the laser welded structure, it is immersed in the SiO2 dispersion system under vacuum;

[0075] The impregnated structure is dried at a controlled temperature and then sintered;

[0076] The surface of the sintered structure is polished.

[0077] For ease of description, the structure after laser welding is called an insulator structure. In this optional embodiment, the waterproof and moisture-proof treatment is achieved by surface treatment (grinding, cleaning, drying), impregnation (immersion in SiO2 dispersion system, impregnation under vacuum environment), temperature control drying, sintering treatment, and polishing treatment of the insulator structure. Among them, the surface treatment can remove impurities and unsaturated bonds on the surface of the insulator structure, improve the surface quality, and facilitate the subsequent impregnation process; impregnation can make the SiO2 dispersion system evenly penetrate into the interior of the insulator structure, form a dense protective layer on the surface and inside of the insulator structure, and improve the moisture-proof performance of the insulator structure; temperature control drying can make the moisture inside the insulator structure fully evaporate, and prevent the insulator structure from cracking due to moisture expansion during sintering; sintering treatment can make the SiO2 dispersion system form a silicon oxide film of a certain thickness inside the insulator structure, and enhance the moisture-proof performance of the insulator structure; polishing treatment can further improve the smoothness and uniformity of the surface of the insulator structure, be beautiful and reduce surface defects, and improve the insulation performance of the insulator structure.

[0078] Optionally, the SiO2 dispersion system includes silica sol and micron-sized quartz powder mixed in a preset ratio.

[0079] In this optional embodiment, silica sol and micron-sized quartz powder are mixed to form a uniform SiO2 dispersion system. SiO2, as an excellent insulating material, can effectively block the penetration of moisture and oxygen, reduce the performance degradation of the insulating structure caused by moisture, and thus help to form a uniform protective layer on the surface and inside of the insulating structure.

[0080] The selection of the preset ratio can be determined according to specific use requirements, process conditions, material properties, etc. Generally speaking, silica sol and micron-sized quartz powder can be mixed in a range of 10:1 to 1:1.

[0081] Optionally, the pH value of the SiO2 dispersion system is 10.

[0082] Under alkaline conditions, the SiO2 dispersion system is more stable, able to maintain a dispersed state and avoid the formation of precipitation or agglomeration; and the surface of SiO2 particles usually carries a negative charge, and alkaline conditions help prevent aggregation between SiO2 and maintain a dispersed state; at the same time, the SiO2 dispersion system under alkaline conditions has better adhesion to the surface of the insulator structure, and can better adhere to and form a protective film; in addition, the SiO2 dispersion system under alkaline conditions has a certain neutralizing effect on acidic substances, which can improve the chemical corrosion resistance of the insulator structure; in addition, alkaline conditions help to improve the SiO2 dispersion system to form a dense protective layer inside the insulator structure, further improving the moisture-proof performance of the insulator 2.

[0083] Optionally, the sintering temperature is 1000°C-1100°C.

[0084] Sintering at the above temperature can promote the formation of the crystal structure in the SiO2 dispersion system, increase the density and compactness of the grain boundaries, and improve the moisture resistance of the insulator 2; it can also prompt the SiO2 dispersion system to form a denser protective layer, effectively preventing the penetration of chemical substances such as acids and alkalis, and improving the corrosion resistance of the insulator 2.

[0085] Optionally, the method for preparing the ceramic material comprises:

[0086] S1, uniformly mixing 30%-80% of ceramic powder, 5%-50% of ceramic precursor, and 1%-20% of sintering aid by volume to obtain a first mixed powder;

[0087] S2, placing the first mixed powder in an inert atmosphere or a first reducing atmosphere for heat treatment;

[0088] S3, mixing 30% of the first mixed powder after S2 with 70% of the solvent to obtain a ceramic slurry;

[0089] S4, dissolving a boron nitride precursor in deionized water to form a saturated solution, and adding the saturated solution dropwise into the ceramic slurry to obtain a mixed slurry;

[0090] S5, drying the mixed slurry to obtain a second mixed powder;

[0091] S6, heat-treating the second mixed powder under a second reducing atmosphere to obtain a modified ceramic powder;

[0092] S7, forming the modified ceramic powder and then sintering it to obtain the ceramic material.

[0093] Optionally, in step S1, the ceramic powder may be one of aluminum oxide, silicon nitride, silicon carbide, and boron nitride, or a combination of two or more thereof, and the powder particle size is 0.25 μm-2.5 μm.

[0094] Optionally, in step S1, the ceramic precursor may be one of aluminum sol, polysilazane, polysiloxane or polysilocarbazine, or a combination of two or more thereof.

[0095] Optionally, in step S1, the sintering aid may be one or a combination of two or more of nano rare earth oxide powder, nano alumina, nano silicon oxide, and inorganic salts and oxides (non-nanoscale) containing magnesium, calcium, strontium and barium elements.

[0096] Optionally, in step S2, the inert atmosphere is argon or nitrogen, and the first reducing atmosphere is argon, or a mixed gas of nitrogen and 10 vol% hydrogen.

[0097] Optionally, in step S2, the heat treatment temperature is 650°C-1400°C, and the heat treatment time is more than 30 minutes.

[0098] Optionally, in step S3, the solvent may be anhydrous ethanol or methanol or other small molecule alcohol substances.

[0099] Optionally, in step S4, the boron nitride precursor includes boron-containing compounds such as boric acid, ammonium tetraborate, ammonium pentaborate, etc. These boron-containing compounds can provide a boron source, and the ammonia or nitrogen gas introduced at high temperature can provide a nitrogen source.

[0100] Optionally, in step S4, when the saturated solution is added dropwise to the ceramic slurry, the slurry is continuously mechanically stirred until the mass ratio of deionized water to anhydrous ethanol in the mixed slurry is 1:40-1:20. In this way, sufficient precipitation and dispersion can be ensured while reducing costs. In addition, the dropwise addition method also makes the precipitate precipitated from the saturated solution finer in particle size.

[0101] Optionally, in step S5, the solvent in the slurry is evaporated by rotary evaporation to obtain a second mixed powder, which is a dried ceramic powder and a boron nitride precursor.

[0102] Optionally, in step S6, the second mixed powder is placed in a crucible, and a flowing second reducing atmosphere is introduced into a high-temperature furnace, the temperature is raised to 800°C-1200°C, and the temperature is kept for 2-10 hours to obtain a modified ceramic powder, which is a nano-BN modified ceramic powder.

[0103] Optionally, the second reducing atmosphere is argon, or a mixed gas of nitrogen and 10 vol% hydrogen, or ammonia, and may be the same as or different from the first reducing atmosphere.

[0104] Optionally, in step S7, the modified ceramic powder is subjected to colloidal molding or powder molding, and then subjected to normal pressure sintering or gas pressure sintering after molding, wherein the sintering temperature is 1500°C-2000°C, and the holding time is 1-4 hours, to obtain a ceramic material with high reliability and high temperature resistance.

[0105] In the related art, the insulator 2 is mostly made of polymer and is molded by thermosetting plastic. However, the working temperature range of polymer is only -65℃ to 350℃. In extreme environments with higher temperatures, the insulation performance drops sharply, and when the temperature rises instantly, the polymer will deform and fail, which cannot meet the use requirements of high-temperature resistant electrical connectors at high temperatures. For example, the insulating dielectric materials of some commonly used high-temperature resistant electrical connectors cannot work normally in extreme high-temperature environments of 800℃ or even thousands of degrees, and the high-temperature resistance is insufficient. For the insulator 2 of the high-temperature resistant electrical connector resistant to more than 800℃, special insulating materials with better temperature resistance such as composite materials can be used, which can maintain certain insulation performance at high temperatures, but due to the high brittleness of the material, it is very easy to be damaged or even broken under vibration, impact, thermal shock, etc., and the material reliability is insufficient. For example, the selection of ceramic materials can maintain high insulation performance at high temperatures, but the material has intrinsic brittleness, insufficient reliability, and there are problems such as greater processing difficulty, inability to achieve the precision processing requirements of high-density insulation boards, and difficulty in meeting the development requirements of high-density high-temperature resistant electrical connectors.

[0106] In order to improve the reliability of high temperature resistant electrical connectors, the above method is used to prepare ceramic materials.

[0107] Specifically, through the design of precursor raw materials and ceramic powder components, a composite ceramic powder in which nano-scale ceramic powder and micron-scale ceramic powder are uniformly mixed in multiple phases is obtained. During the preparation process, a series of chemical changes occur between the raw materials, including: precursor cracking (precursor cracking generates nano-scale boron oxide, silicon oxide, aluminum oxide, etc.), a series of phase changes (including boron oxide reacting with nitrogen to generate hexagonal boron nitride; silicon oxide reacting with nitrogen to generate silicon nitride, etc.) and chemical reaction with the main crystalline phase ceramic powder (including rare earth oxides reacting with precursor cracking products to generate a molten phase, promoting mass transfer and sintering of the main crystalline phase ceramic). In addition, due to the high surface energy of nanopowders, the chemical reaction between the raw materials is accelerated and the sintering activity is improved, and finally a ceramic material with a microstructure of micron-scale rod crystals with a high aspect ratio and nano-scale plate crystals with a high aspect ratio is generated in situ.

[0108] After testing, the ceramic material prepared by the above method has an operating temperature of up to 800°C, a high temperature insulation resistance of ≥100MΩ, high reliability at high temperatures, and anti-vibration (frequency range 10-2000Hz, acceleration 196m / s 2 ), impact resistance (impact acceleration 490m / s 2 , half-sine wave, impact time is 11ms, 3 impacts in each of the three axes).

[0109] Optionally, the ceramic material is precision machined using a CNC machine tool to obtain a cylindrical insulator 2 .

[0110] The above ceramic materials are processed into Figure 3 The insulator 2 shown has the following advantages after experiments:

[0111] (1) High heat resistance temperature, greater than 1700°C; and strong resistance to thermal shock. Specifically, after the prepared insulator 2 is heated to 1700°C, it is directly placed in cold water and subjected to 10 thermal shocks without being damaged, meeting the requirements of harsh service environments. However, some commercial ceramic materials will be significantly damaged or destroyed after only one thermal shock under the above conditions.

[0112] (2) Stable high-temperature insulation performance. The insulation performance test of insulator 2 showed the following results: the insulation resistance at room temperature was greater than 1000 MΩ, the insulation resistance at 200°C was greater than 1000 MΩ, and the insulation resistance at 800°C was greater than 100 MΩ, meeting the high-temperature insulation performance requirements.

[0113] (3) Through near-net-shape forming, the machinability and processing precision of the material are improved. At the same time, due to the high reliability of the material, it can be processed using ordinary machine tools, which can reduce the batch production processing cost by more than 50% compared with traditional homogeneous ceramics, save more than 80% of production time costs, and realize low-cost batch precision preparation of extremely small-sized components, and ultimately realize low-cost batch precision preparation of insulator 2.

[0114] The present invention is further described below in conjunction with specific embodiments.

[0115] Example 1

[0116] This embodiment provides a method for preparing a high temperature resistant electrical connector plug, which is specifically as follows:

[0117] The ceramic material is precisely machined by a CNC machine tool to obtain a cylindrical insulator 2 (as shown in the figure). It can be understood that the cylindrical insulator 2 has a hole structure 21 inside for assembling the pins;

[0118] The insulator 2 and the open ring structure 3 are arranged as follows: Figure 8 Assembled together as shown, and brazed; specifically, solder paste is coated on the surface of the insulator 2 and the surface of the hole structure 21, and vacuum brazed with the stainless steel open ring structure 3 and the metal pin at high temperature;

[0119] The brazed assembly is assembled with the stainless steel housing 4 by laser welding, and the insulator structure is subjected to moisture-proof treatment to obtain a high-temperature resistant electrical connector plug.

[0120] Comparative Example 1

[0121] The difference from Example 1 is that after the cylindrical insulator 2 is processed by a CNC machine tool, the insulator 2 and the stainless steel shell 4 are assembled by laser welding, and the insulator structure is subjected to moisture-proof treatment to obtain a high-temperature resistant electrical connector plug.

[0122] Effect Example

[0123] The high temperature resistant electrical connector of Example 1 reduces stress concentration during welding between the ceramic and the housing 4 through structural design. To verify this effect, simulation tests are performed on the high temperature resistant electrical connectors prepared in Example 1 and Comparative Example 1, respectively. The simulation results are as follows:

[0124] First of all, it should be noted that at high temperatures, the thermal expansion coefficient of stainless steel is more than 5 times that of silicon nitride ceramic material, and the expansion degree of stainless steel at high temperatures is greater than that of the ceramic insulator 2. Therefore, the stress concentration between the stainless steel pin and the ceramic is not considered. The stress condition of the 800°C high-temperature resistant electrical connector in service is simulated mainly by considering the thermal stress condition at the interface between the ceramic and the stainless steel shell 4 in service.

[0125] In comparative example 1, no open ring structure 3 is provided between the housing 4 and the insulator 2. In this case, the outer stainless steel housing 4 and the ceramic insulator 2 are directly welded. The structural diagram is shown in FIG. Fig. 9 Wherein, the thickness of the stainless steel shell 4 is 0.5 mm.

[0126] In Example 1, an open ring structure 3 is provided between the shell 4 and the insulator 2, and the open ring structure 3 is made of the same stainless steel material as the shell 4. At this time, the ceramic insulator 2 is welded to the stainless steel open ring structure 3 instead of being directly welded to the stainless steel metal shell 4. The structure of the welding assembly of the insulator 2 and the open ring structure 3 is shown in FIG. Figure 8 Wherein, the thickness of the stainless steel open ring structure 3 is 0.5 mm.

[0127] The stress at the interface of the above two structures when in service at 800℃ was simulated and analyzed, and the results are as follows: Fig.10 , Fig.11 As shown. It can be seen that in Example 1, the stress between the ceramic and the stainless steel shell 4 is significantly reduced, and the stainless steel open ring structure 3 only has a large stress at the notch 33, and the stress concentration at the notch 33 can be further released during the subsequent laser welding with the stainless steel shell 4, so it can effectively solve the problem of internal loosening, deformation or fracture of the connector seal caused by stress concentration when serving at high temperature.

[0128] It can be seen that the high temperature resistant electrical connector of Example 1 reduces the stress concentration during welding of the ceramic and the metal housing 4 through structural design, and the simulation verifies that the stress reduction effect is obvious. In addition, according to the test, the airtightness of the high temperature resistant electrical connector of Example 1 is less than 1E-10Pa·m in the initial state. 3 / s(i.e. 1*10 -10 Pa·m 3 / s), after each test, it is not more than 1E-6Pa·m 3 / s(i.e. 1*10 -6 Pa·m 3 / s), meeting the airtightness requirements for use under high temperature.

[0129] In summary, the embodiment of the present invention realizes low-cost, high-efficiency, and batch preparation of ceramic insulators 2 with excellent properties such as high reliability, high temperature resistance, easy processing, and stable high-temperature insulation performance. It can replace commonly used engineering plastics and electronic glass, greatly improve the high-temperature use reliability of the high-temperature resistant electrical connector insulator 2, and significantly reduce production costs and shorten production cycles. It can be applied to high-temperature resistant electrical connectors in multiple fields such as aerospace and electronics industries, and has great application value and social and economic benefits. At the same time, by adding a stainless steel open ring structure 3 between the stainless steel shell 4 and the insulator 2, the stress concentration at the welding interface between ceramic and stainless steel is significantly improved, and brazing is used instead of the traditional glass sealing method, which solves the problem of insufficient service sealing of high-temperature resistant electrical connectors at a high temperature of 800°C, and solves the electrical connection problem of special equipment interfaces under high temperature extreme working conditions. The technology has very strong scalability, which helps to achieve the replacement of similar products and the development of similar products.

[0130] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A high temperature resistant electrical connector, characterized in that: The invention comprises a contact body (1), an insulator (2), an outer shell (4) and an open ring structure (3), wherein the insulator (2) is sleeved on the contact body (1), and the outer shell (4) is sleeved on the outside of the insulator (2); the open ring structure (3) is arranged between the insulator (2) and the outer shell (4), and the open ring structure (3) comprises an annular side wall (32) and a base (31) connected to one axial end of the annular side wall, wherein the base (31) and the annular side wall (32) form a cavity for accommodating the insulator (2), and a notch (33) is arranged on the annular side wall (32), wherein the notch (33) extends along the axial direction of the annular side wall (32) and one end of the notch is connected to the opening of the cavity.

2. The high temperature resistant electrical connector according to claim 1, characterized in that: There are a plurality of the notches (33), and the plurality of the notches (33) are evenly arranged along the circumference of the annular side wall (32).

3. The high temperature resistant electrical connector according to claim 1, characterized in that: The vertical cross-section of the notch (33) is rectangular; and / or the other end of the notch (33) extends to the connection between the annular side wall (32) and the base (31).

4. The high temperature resistant electrical connector according to claim 1, characterized in that: The material of the open ring structure (3) is the same as that of the outer shell (4).

5. The high temperature resistant electrical connector according to claim 1, characterized in that: The materials of the open ring structure (3) and the outer shell (4) are both stainless steel, and the material of the insulator (2) is ceramic.

6. A method for preparing a high temperature resistant electrical connector, characterized in that: Used to prepare a high temperature resistant electrical connector as claimed in any one of claims 1 to 5, comprising: Processing the ceramic material into a cylindrical shape to obtain an insulator (2); Assembling the insulator (2), the contact body (1) and the open ring structure (3) together, and performing brazing to obtain a brazed assembly; The brazing assembly is assembled with the housing (4) and laser welded to obtain a high temperature resistant electrical connector.

7. The method for preparing a high temperature resistant electrical connector according to claim 6, characterized in that: Also includes: The laser welded structure is treated with moisture-proof treatment.

8. The method for preparing a high temperature resistant electrical connector according to claim 7, characterized in that: The moisture-proof treatment of the laser-welded structure comprises: After grinding, cleaning and drying the surface of the laser welded structure, it is immersed in the SiO2 dispersion system under vacuum; The impregnated structure is dried at a controlled temperature and then sintered; The surface of the sintered structure is polished.

9. The method for preparing a high temperature resistant electrical connector according to claim 8, characterized in that: The SiO2 dispersion system comprises silica sol and micron-sized quartz powder mixed in a preset ratio.

10. The method for preparing a high temperature resistant electrical connector according to claim 6, characterized in that: The preparation method of the ceramic material comprises: S1, uniformly mixing 30%-80% of ceramic powder, 5%-50% of ceramic precursor, and 1%-20% of sintering aid by volume to obtain a first mixed powder; S2, placing the first mixed powder in an inert atmosphere or a first reducing atmosphere for heat treatment; S3, mixing 30% of the first mixed powder after S2 with 70% of the solvent to obtain a ceramic slurry; S4, dissolving a boron nitride precursor in deionized water to form a saturated solution, and adding the saturated solution dropwise into the ceramic slurry to obtain a mixed slurry; S5, drying the mixed slurry to obtain a second mixed powder; S6, heat-treating the second mixed powder under a second reducing atmosphere to obtain a modified ceramic powder; S7, forming the modified ceramic powder and then sintering it to obtain the ceramic material.

Images