An ultra-lightweight radio frequency cable assembly for aerospace applications and a method of assembling the same

Abstract

The application discloses a kind of aerospace ultra-light radio frequency cable assemblies and its assembling method, and the assembly is formed by soldering tin, heat shrink sleeve termination of radio frequency coaxial cable and two radio frequency coaxial connectors;Radio frequency coaxial connector includes connecting nut, shell, first insulator, pin, clamping spring, sleeve, second insulator, solder sleeve and fastening nut.Aerospace ultra-light radio frequency cable uses aramid fiber as outer shielding net, the application adopts segmented stripping method and two kinds of soldering tin methods to strip and tin radio frequency coaxial cable, solves the problem that shielding net is easily loose, effectively reduces installation difficulty, novel and reliable structure, simple and easy to operate assembling method, cable assembly can maintain stable performance after multiple bending, realize the connection between interfaces in any position in space.

Description

Technical Field

[0001] This invention belongs to the field of microwave radio frequency passive devices, and specifically relates to a cable assembly, particularly an ultra-lightweight radio frequency cable assembly for aerospace applications with space application capabilities. Background Technology

[0002] Existing cable assemblies, employing traditional connector structures and ordinary RF cables, cannot simultaneously meet the lightweight load-bearing requirements of aerospace applications, as well as the low-reflection and low-loss requirements of the high-temperature and high-radiation space environment. Traditional aerospace RF cable assemblies are heavy and have weak transmission capabilities, failing to meet current application development trends. Furthermore, traditional ultralightweight aerospace RF cables use aramid fiber as the outer shielding mesh, which is extremely difficult to install due to the difficulty in tinning the cable, the easy loosening of the shielding mesh, and the challenges in soldering and assembly. Moreover, their reliability deteriorates after repeated bending or temperature changes, and the internal structure of the cable alters, leading to increased return and insertion losses, resulting in heat dissipation and lifespan reliability issues, thus reducing the overall reliability of the product. Therefore, there is an urgent need to design an improved ultralightweight cable assembly to enhance the performance and reliability of the entire satellite communication system. Summary of the Invention

[0003] The technical problem solved by this invention is to address the shortcomings of existing technologies by proposing an ultralight RF cable assembly for aerospace applications and its assembly method. It employs a connector with low reflection and low loss in high vacuum environments, and is coupled with an ultralight RF coaxial cable with a silver-plated aramid fiber outer shielding layer. The assembly method is novel, reliable, simple, and easy to operate, and maintains stable performance even after multiple bends, enabling connections between interfaces at any spatial location.

[0004] The technical solution of the present invention is: an ultra-lightweight radio frequency cable assembly for aerospace applications, which is formed by terminating a radio frequency coaxial cable and two radio frequency coaxial connectors by soldering and heat shrink tubing; both ends of the radio frequency coaxial cable are respectively connected to a connector through a cable sleeve; at each end of the radio frequency coaxial cable, the cable sleeve is simultaneously fitted onto the end section of both the radio frequency coaxial cable and the radio frequency coaxial connector.

[0005] The radio frequency coaxial connector includes a connecting nut, a housing, a first insulator, a pin, a retaining ring, a sleeve, a second insulator, a solder sleeve, and a fastening nut. The connecting nut is fitted onto the housing via the retaining ring. The fastening nut is limited by the solder sleeve, which is soldered onto the cable to fix the radio frequency coaxial connector. The fastening nut is screwed onto the housing. The first insulator, pin, sleeve, and second insulator are all assembled inside the housing. The first insulator is fitted onto the step of the pin and serves to support the inner and outer conductors of the radio frequency coaxial connector and provide impedance matching. The pin is assembled inside the sleeve.

[0006] The outer edge of the housing includes a first step with gradually increasing diameter, a lower groove for the retaining ring, a second step, and a tail end of the housing arranged sequentially. The lower groove for the retaining ring is used to limit the inner ring of the retaining ring and ensure the installation of the connecting nut. A stepped structure is provided at the front end of the lower groove for preventing the connecting nut from falling off when the inner ring of the retaining ring comes out. The inner cavity of the housing includes a first cavity, a second cavity, a third cavity, a fourth cavity, a fifth cavity, a pusher groove, and an internal threaded cavity section arranged sequentially. The diameters of the first cavity, the second cavity, the third cavity, the fourth cavity, the fifth cavity, and the pusher groove increase sequentially. A first step surface is formed between the second cavity and the third cavity, a second step surface is formed between the third cavity and the fourth cavity, and a third step surface is formed between the fourth cavity and the fifth cavity. The first step surface is used to limit the first insulator, the second step surface is used to limit the sleeve, the third step surface is used to limit the welding sleeve, and the threaded cavity section is used to engage with the external thread of the first end of the fastening nut.

[0007] The inner cavity of the connecting nut includes a threaded cavity section and a grooved cavity section. The threaded cavity section is used to connect with the external thread on the external connector. The upper groove of the retaining ring is installed on the cavity wall of the grooved cavity section. When installed in place, the lower groove of the retaining ring corresponds to the upper groove of the retaining ring, and the retaining ring is assembled in the lower groove of the retaining ring of the connecting nut and the upper groove of the retaining ring of the housing.

[0008] The first insulator is made of polyetherimide and has an integral injection-molded fan-shaped structure. Both circular surfaces have four grooves of varying depths. The first insulator is fitted onto the pin through the central hole, and the side steps of the first insulator are in close contact with the first step surface.

[0009] The second insulator is made of polyetherimide and has a disc structure with a central hole in the center. Six holes are evenly distributed around the central hole in a symmetrical manner. The second insulator is fitted onto the cable core through the central hole. The second insulator is inserted into the sleeve with a clearance fit. When installed in place, one side of the second insulator is in close contact with the sleeve, and the other side is in close contact with the external cable end face.

[0010] The pin has a sequentially connected cylindrical stepped structure, consisting of a first stage, a second stage, and a pin tail section. The front cylindrical section of the first stage is designed according to the interface size requirements and is used to insert into the socket of an external connector for electrical connection. A first insulator is fitted on the second stage. A central hole is drilled at the bottom of the pin tail section, and an observation hole is drilled on the side of the pin tail section. The core of the RF coaxial cable first passes through the central hole of the second insulator and then extends into the central hole of the pin. The core of the RF coaxial cable is fixed to the pin by welding. The observation hole is used to observe the amount of solder. The amount of solder should fill the observation hole without protruding.

[0011] The sleeve contains a first cavity, a second cavity, and a third cavity arranged sequentially inside. The first cavity is an impedance compensation cavity, which plays an auxiliary role in coplanar compensation. The second cavity is a transmission cavity. The third cavity is an insulator cavity, used to install the second insulator. When installed in place, the disc surface of the second insulator is in close contact with the step. The sleeve is inserted into the fourth cavity with a clearance fit, and the first cavity is close to the second step surface.

[0012] The outer edge of the welding sleeve has a first cylindrical section, a step, and a second cylindrical section arranged sequentially. The inside of the welding sleeve includes a first cavity and a second cavity arranged sequentially. The inner wall of the first cavity of the welding sleeve is soldered to the outer metal shielding layer of the cable. The second cavity is fitted onto the cable sheath. When installed in place, the front end of the welding sleeve is in close contact with the third step, which is used to limit the housing and fasten the nut.

[0013] The fastening nut passes through the cable and is finally fitted onto the welding sleeve, which is further fitted onto one end of the radio frequency coaxial cable by welding. The outer edge of the fastening nut includes a first end and a second end arranged in sequence. The first end is provided with an external thread and is limited by a step. When installed in place, the first end engages with the threaded cavity section, and the front end face of the fastening nut is in close contact with the step.

[0014] A method for assembling an ultralight radio frequency cable assembly for aerospace applications, comprising:

[0015] The cable ends are stripped using a segmented stripping method, and the stripping dimensions must be matched with the dimensions of the pin, the second insulator, and the welding sleeve.

[0016] After stripping the first section of outer sheath using a wire stripping machine, the first section is tinned. The tinning method for the first section is to directly immerse the first section in a tin pot and immerse it for a period of time so that an appropriate amount of tin is attached to the outer shielding mesh. This should meet the welding requirements but not be too much, which would affect the installation of the solder sleeve.

[0017] Cut the second outer sheath; the second outer sheath does not need to be peeled off, but is pushed directly to the position where the first section has been tinned, and the second shielding mesh is tinned; the tinning method for the second section is: directly use a soldering iron to apply tin so that a thin layer of solder is evenly coated on the surface; then remove the moved outer sheath; strip the wire core according to the wire stripping requirements, and wait for soldering;

[0018] Secure the fastening nut to the cable end, and then spirally wrap the solder wire around the section where the shielding mesh has been removed. The adjacent loops should be tightly fitted together. Place the solder sleeve onto the cable with the solder wire wrapped around it, and make sure it is tightly fitted to the end face of the solder sleeve. Use a high-impedance soldering machine to solder the solder sleeve. Do not change the position of the solder sleeve and the solder wire during clamping. Then solder, and the soldering time should be controlled within 20 seconds. After the solder melts, it should flow into the gap between the solder sleeve and the cable shielding layer.

[0019] Insert the snap ring into the snap ring groove of the housing, clamp the snap ring with round-nose pliers, and then use a wrench to put the connecting nut on the housing. Release the round-nose pliers, and the outer ring of the snap ring will fall into the snap ring groove of the connecting nut. When installed in place, the connecting nut can rotate freely on the housing without falling off.

[0020] The first insulator is installed into the third cavity of the housing, and the sleeve is then installed into the fourth cavity. The second insulator is installed on the cable core, and solder is filled into the center hole of the pin. Then the core is inserted into the center hole of the pin, and the pin is soldered onto the cable core. The cable end, along with the installed fastening nut, solder sleeve, second insulator, and pin, is installed into the housing. The first end of the fastening nut is tightened into the threaded section inside the housing, and the tightened connector and cable connection are heat-shrinked with a heat-shrinkable sleeve.

[0021] Once installed, the inner wall of the first cavity of the welding sleeve is soldered to the metal shielding layer of the cable. The first insulator is fitted onto the second step of the pin, and the second insulator is fitted onto the cable core. The cable core passes through the center hole of the pin, and the cable core and the pin are connected together by solder. The sleeve is installed in the fourth cavity of the housing. One side of the first insulator is in close contact with the first step surface inside the housing, and the other side is in close contact with the front end of the sleeve. The second insulator is installed in the third cavity of the sleeve, with one side in close contact with the sleeve step and the other side in close contact with the cable end face. The front end face of the welding sleeve is in close contact with the third step surface of the housing. The thread of the threaded cavity section of the housing mates with the external thread on the first end of the fastening nut. The snap ring is assembled in the lower and upper slots of the snap ring, and the connecting nut is fitted onto the housing through the snap ring. The cable sleeve covers the outside of the RF coaxial cable, the second end of the fastening nut, and the tail end of the housing.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) This invention employs a dual-segment structure for the first and second insulators, which enhances the mechanical properties of the invention compared to a traditional single insulator with a cylindrical stepped structure. The first insulator is an integrally injection-molded fan-shaped structure, which has better impedance matching and higher mechanical properties compared to traditional insulators, thus giving the invention high reliability. The second insulator effectively prevents deformation of the cable insulation layer caused by temperature changes, giving the invention resistance to high and low temperature environments in aerospace applications.

[0024] (2) The present invention adopts an integral injection-molded fan-type structure for the insulator, with four grooves on each side, two of which are deep and two are shallow, which is a coplanar compensation structure; the second cavity inside the shell and the first cavity inside the sleeve provide air coplanar compensation for the first insulator; this double coplanar compensation structure effectively improves the microwave performance of the product, giving the present invention good signal transmission capability.

[0025] (3) The front end of the circlip groove on the housing of the present invention is provided with a stepped structure. When the connecting nut is rotated, this structure can make the circlip spring back into the circlip groove, effectively preventing the inner ring of the circlip from coming out and preventing it from falling off when the connecting nut is tightened multiple times, so that the present invention has a long service life.

[0026] (4) The radio frequency coaxial cable selected in this invention meets the lightweight requirements of aerospace applications. Its shielding layer is made of silver-plated aramid fiber, which is extremely difficult to weld. This invention adopts a segmented stripping method—stripping the wire in two segments and two special tinning methods—tin pot immersion and soldering iron tinning, which effectively solves the problems of the cable being difficult to tin, the shielding mesh being very easy to loosen, and the difficulty of soldering and assembling.

[0027] (5) The connector structure, installation method and radio frequency cable structure of the present invention make the present invention lighter in weight, wider in operating frequency band, better in microwave transmission performance and space environment resistance than traditional cable assemblies. It realizes an ultra-lightweight radio frequency cable assembly for aerospace, with an operating frequency of DC to 40GHz, a standing wave ratio of less than 1.25, an operating temperature of -100℃ to +150℃ (200 temperature changes), and a mechanical shock resistance of 1000g. The weight is more than 30% lower than that of traditional cable assemblies. It can work in a high vacuum environment and realize the connection between interfaces at any position in space. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the external structure of the cable assembly according to the present invention;

[0029] Figure 2 This is a schematic cross-sectional view of the overall structure of one side connector according to the present invention;

[0030] Figure 3 This is an exploded view of the connector according to the present invention;

[0031] Figure 4a This is a schematic diagram of the external appearance of the housing according to the present invention. Figure 4b This is a sectional view of the shell;

[0032] Figure 5 This is a cross-sectional view of the connecting nut according to the present invention;

[0033] Figure 6 This is a schematic diagram of the first insulator according to the present invention;

[0034] Figure 7 This is a schematic diagram of the second insulator according to the present invention;

[0035] Figure 8 This is a schematic diagram of the insert according to the present invention;

[0036] Figure 9 This is a schematic diagram of the sleeve according to the present invention;

[0037] Figure 10a This is a schematic diagram of the appearance of the welding sleeve according to the present invention;

[0038] Figure 10b A cross-sectional view of the welding sleeve according to the present invention.

[0039] Figure 11 This is a schematic diagram of the fastening nut according to the present invention;

[0040] Figure 12a , 12b 12c is a schematic diagram of the segmented wire stripping and tinning method of the present invention;

[0041] Figure 13 This is a schematic diagram of the radio frequency cable termination stripping structure according to the present invention;

[0042] Figure 14 A schematic diagram of the welding sleeve structure for the radio frequency cable according to the present invention. Detailed Implementation

[0043] The ultra-lightweight radio frequency cable assembly for aerospace applications according to the present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0044] like Figure 1 As shown, the aerospace-grade ultralight radio frequency cable assembly of the present invention comprises a radio frequency coaxial cable 10 and two radio frequency coaxial connectors terminated by soldering and heat shrink tubing. Figure 2 , 3 As shown, the radio frequency coaxial connector consists of a connecting nut 1, a housing 2, a first insulator 3, a pin 4, a retaining ring 5, a sleeve 6, a second insulator 7, a solder sleeve 8, and a fastening nut 9.

[0045] like Figure 4bAs shown, the outer surface of the housing 2 includes four sequentially arranged parts: a first step 21, a retaining ring groove 22, a second step 23, and a housing tail end 24. The diameters of the four parts gradually increase. The retaining ring groove 22 is used to limit the inner ring of the retaining ring, ensuring the installation of the connecting nut. The front end of the retaining ring groove 22 is provided with a stepped structure 221, which effectively prevents the connecting nut 1 from falling off when the inner ring of the retaining ring 5 comes out. The inner cavity of the housing 2 includes a first cavity 251, a second cavity 252, a third cavity 253, a fourth cavity 254, a fifth cavity 255, a pusher groove 256, and an internal threaded cavity section 257, wherein... The diameters of the first cavity 251, the second cavity 252, the third cavity 253, the fourth cavity 254, the fifth cavity 255, and the pusher groove 256 increase sequentially. A first step surface 26 is formed between the second cavity 252 and the third cavity 253, a second step surface 27 is formed between the third cavity and the fourth cavity, and a third step surface 28 is formed between the fourth cavity and the fifth cavity. The first step surface 26 is used to limit the first insulator 3, the second step surface 27 is used to limit the sleeve 6, and the third step surface is used to limit the welding sleeve 8. The internal threaded cavity section 257 of the housing 2 is used to engage with the external thread of the first end 91 of the fastening nut 9.

[0046] like Figure 5 As shown, the inner cavity of the connecting nut 1 includes a threaded cavity section 11 and a grooved cavity section 12. The threaded cavity section 11 is used to connect with the external thread on the external connector. The cavity wall of the grooved cavity section 12 has an upper groove 13 for the retaining ring. When installed in place, the lower groove 22 of the retaining ring corresponds to the upper groove 13 of the retaining ring, and the retaining ring 5 is assembled in the lower groove 22 of the connecting nut and the upper groove 13 of the housing retaining ring.

[0047] like Figure 6 As shown, the material of the first insulator 3 is polyetherimide. The first insulator 3 is an integral injection molded fan-shaped structure. Both circular surfaces have four grooves with a depth of two deep grooves of 33 and two shallow grooves of 34, which are distributed alternately. The first insulator 3 is fitted onto the second stage 42 of the pin 4 through the central hole 31. The side step 32 of the first insulator 3 is in close contact with the first step surface 26 of the shell 2.

[0048] like Figure 7 As shown, the material of the second insulator 7 is polyetherimide. The second insulator 7 has a disc structure with a central hole 71 in the center. There are 6 holes 73 evenly distributed around the central hole 71, which are centrally symmetrical. The second insulator 7 is fitted onto the cable core 112 through the central hole 71. The second insulator 7 is inserted into the third cavity 63 of the sleeve 6 with a clearance fit. When installed in place, one side is in close contact with the step 64 of the sleeve 6 and the other side is in close contact with the external cable end face 111.

[0049] like Figure 8As shown, the pin 4 has a sequentially connected cylindrical stepped structure, including a first stage 41, a second stage 42, and a pin tail section 43. The front cylindrical part of the first stage 41 is designed according to the interface size requirements and is used to insert into the socket of an external connector for electrical connection. The second stage 42 is fitted with a first insulator 3. A central hole 45 is drilled at the bottom of the pin tail section 43, and an observation hole 44 is drilled on the side of the pin tail section 43. The core 112 of the RF coaxial cable first passes through the central hole 71 of the second insulator 7 and then extends into the central hole 45 of the pin 4. The core 112 of the RF coaxial cable is fixed to the pin 4 by welding. The observation hole 44 is used to observe the flow of solder during welding. The amount of solder should fill the observation hole 44 without protruding.

[0050] like Figure 9 As shown, the sleeve 6 has a first cavity 61, a second cavity 62, and a third cavity 63 arranged sequentially inside. The first cavity 61 is an impedance compensation cavity, which plays an auxiliary coplanar compensation role. The second cavity 62 is a transmission cavity, and the third cavity 63 is an insulator cavity, which is used to install the second insulator 7. When installed in place, the disc surface of the second insulator 7 is in close contact with the step 64. The sleeve 6 is inserted into the fourth cavity 254 of the housing 2 with a clearance fit. The first cavity 61 is close to the second step surface 27 of the housing 2.

[0051] As shown in Figure 10, the outer edge of the welding sleeve 8 is distributed with a first cylindrical section 81, a step 83 and a second cylindrical section 82. The inside of the welding sleeve 8 includes a first cavity 841 and a second cavity 842 arranged in sequence. The inner wall of the first cavity 841 of the welding sleeve is soldered to the outer cable metal shielding layer 113. The second cavity 842 is fitted onto the cable sheath. When installed in place, the front end of the welding sleeve 8 is close to the third step 28 of the housing 2. The function of the welding sleeve is to limit the housing 2 and the fastening nut 8, so that the two can be connected together by threads.

[0052] like Figure 11 As shown, the outer edge of the fastening nut 9 includes a first end 91 and a second end 92 arranged in sequence. The fastening nut 9 passes through the cable and is finally fitted onto the welding sleeve 8. The welding sleeve 8 further fits one end of the radio frequency coaxial cable by welding. The first end 91 of the fastening nut 9 is provided with an external thread, and the first end 91 is limited by a step 83 provided on the first end of the welding sleeve 8. When installed in place, the first end 91 of the fastening nut 9 is screwed into the internal thread cavity 257 of the housing 2, and the front end face 93 of the fastening nut 9 is in close contact with the step 83 on the first end of the welding sleeve 8.

[0053] Because the shielding mesh of the ultralight cable 10 is made of aramid fiber, a non-metallic fiber, the woven mesh is relatively loose. Therefore, it is necessary to use handheld soldering equipment to tin the shielding mesh at the cable ends to keep it round. Figure 12a , Figure 12b , Figure 12c As shown, the present invention uses a segmented wire stripping and tinning method during installation. After the outer sheath of the first segment 101 is stripped using a wire stripping machine, the first segment 101 is tinned. Then, the outer sheath of the second segment 102 is cut. The outer sheath of the second segment 102 does not need to be stripped. Instead, it is pushed directly to the position where the first segment has been tinned. After the second segment of the shielding mesh 103 is tinned, the moved outer sheath 102 is removed. At this time, the non-metallic woven shielding mesh is completely intact.

[0054] like Figure 13 As shown, the tinned cable is stripped according to the diagram. The stripping dimensions must match the dimensions of the pin 4, the second insulator 7, and the welding sleeve 8 to ensure proper welding fit.

[0055] like Figure 14 As shown, solder wire is wound in a spiral shape on the part of the shielding mesh 113 that has been stripped, and the adjacent loops should be tightly closed. The solder sleeve 8 is put on the cable 10 with the solder wire wound on it. The two ends of the solder sleeve are clamped using an impedance soldering device, and the solder sleeve is heated with heating parameters of 180°C for 20 seconds, so that the solder is evenly filled between the solder sleeve and the shielding layer.

[0056] After stripping the cable, fit the welding sleeve 8 onto the cable as shown in the diagram. The stripping dimensions must match the dimensions of the pin 4, the second insulator 7, and the welding sleeve 8 to ensure proper welding fit.

[0057] The assembly process of an ultralight radio frequency cable assembly for aerospace applications according to the present invention is described below:

[0058] The specific assembly process is as follows: wire stripping - tinning - soldering - assembly;

[0059] according to Figure 12a , Figure 12b , Figure 12c The cable ends are stripped using a segmented stripping method. After stripping the first section 101 of the outer sheath using a stripping machine, the first section 101 is tinned. The tinning method for this section is as follows: the first section is directly immersed in a tin pot for 8 seconds. Utilizing the siphon principle, an appropriate amount of tin is applied to the outer shielding mesh, which meets the welding requirements without being too much and affecting the installation of the solder sleeve. Then, the second section of the outer sheath 102 is cut. The second section of the outer sheath 102 does not need to be stripped; instead, it is directly pushed to the position where the first section has been tinned. The second section of the shielding mesh 103 is then tinned. The tinning method for this section is as follows: tin is applied directly using a soldering iron, so that a thin layer of solder is evenly coated on the surface. Finally, the moved outer sheath 102 is removed. At this point, the non-metallic woven shielding mesh is completely intact.

[0060] according to Figure 14 The cable ends are stripped, and the stripping dimensions must match the dimensions of the pin 4, the second insulator 7, and the welding sleeve 8.

[0061] Secure the cable end with a fastening nut 9, and then spirally wrap solder wire around the portion of the cable from which the shielding mesh 113 has been removed. Adjacent loops should be tightly fitted together. Place the solder sleeve 8 onto the cable 10 with the solder wire wrapped around it, ensuring it is flush against the end face of the sleeve. Use a high-impedance soldering machine to solder the sleeve. Do not change the position of the sleeve or solder wire during clamping. Soldering time should be controlled within 20 seconds. After the solder melts, it should flow into the gap between the sleeve and the cable shielding layer.

[0062] Insert the snap ring 5 into the snap ring groove of the housing 2, clamp the snap ring 5 with round-nose pliers, and then use a wrench to install the connecting nut 1 onto the housing 2. Release the round-nose pliers, and as the installation process proceeds, the outer ring of the snap ring 5 falls into the snap ring groove 13 of the connecting nut 1. When installed in place, the connecting nut 1 can rotate freely on the housing 2 without falling off. Install the first insulator 3 into the third cavity 23 inside the housing 2, and then install the sleeve 6 into the fourth cavity 24. Install the second insulator 7 onto the cable core 112, and then insert the core 112 into the center hole 45 of the pin 4 filled with solder. Solder the pin 4 onto the cable core 112. The end of the cable 10, along with the installed fastening nut 9, solder sleeve 8, second insulator 7, and pin 4, is installed into the housing 2. Tighten the first end 91 of the fastening nut 9 into the threaded cavity section 257 inside the housing 2, and heat shrink the connector and cable connection with a heat shrink sleeve.

[0063] The cable assembly of this invention features an integrated first and second insulator, a pin, and a cable metal core 112 welded together. This connection method offers high mechanical strength, low return loss, minimal losses, stable internal temperature difference at high and low temperatures, and improved microwave transmission capability of the connector. Simultaneously, the connector's structural design effectively simplifies the assembly of ultra-lightweight cables, optimizes resistance to spatial environments, and results in a lightweight cable assembly with strong temperature resistance and mechanical strength, thus enhancing its spatial tolerance.

Claims

1. A method for assembling an aerospace radio frequency cable assembly, wherein the aerospace radio frequency cable assembly is formed by terminating a radio frequency coaxial cable (10) and two radio frequency coaxial connectors by soldering and heat shrink tubing; both ends of the radio frequency coaxial cable are respectively connected to a connector through a cable sleeve; at each end of the radio frequency coaxial cable, the cable sleeve is simultaneously fitted onto the end section of both the radio frequency coaxial cable and the radio frequency coaxial connector; The radio frequency coaxial connector includes a connecting nut (1), a housing (2), a first insulator (3), a pin (4), a retaining ring (5), a sleeve (6), a second insulator (7), a solder sleeve (8), and a fastening nut (9). The connecting nut (1) is fitted onto the housing (2) via the retaining ring (5). The fastening nut (9) is limited by the solder sleeve (8), which is welded to the cable to fix the radio frequency coaxial connector. The fastening nut (9) is screwed onto the housing (2). The first insulator (3), the pin (4), the sleeve (6), and the second insulator (7) are all assembled inside the housing (2). The first insulator (3) is fitted onto the step of the pin (4), and the first insulator (3) serves to support the inner and outer conductors of the radio frequency coaxial connector and to match the impedance. The pin (4) is assembled inside the sleeve (6). The outer edge of the housing (2) includes a first step (21) with gradually increasing diameter, a retaining ring groove (22), a second step (23), and a housing tail end (24) arranged in sequence; the retaining ring groove (22) is used to limit the inner ring of the retaining ring to ensure the installation of the connecting nut; the front end of the retaining ring groove (22) is provided with a stepped structure (221) to prevent the connecting nut (1) from falling off when the inner ring of the retaining ring (5) comes out; the inner cavity of the housing (2) includes a first cavity (251), a second cavity (252), a third cavity (253), a fourth cavity (254), a fifth cavity (255), a pusher groove (256), and an internal thread cavity section (257) arranged in sequence; wherein, The diameters of the first cavity (251), the second cavity (252), the third cavity (253), the fourth cavity (254), the fifth cavity (255), and the pusher groove (256) increase sequentially. A first step surface (26) is formed between the second cavity (252) and the third cavity (253), a second step surface (27) is formed between the third cavity (253) and the fourth cavity (254), and a third step surface (28) is formed between the fourth cavity (254) and the fifth cavity (255). The first step surface (26) is used to limit the first insulator (3), the second step surface (27) is used to limit the sleeve (6), the third step surface is used to limit the welding sleeve (8), and the internal thread cavity section (257) is used to engage with the external thread of the first end (91) of the fastening nut (9). The inner cavity of the connecting nut (1) includes a threaded cavity section (11) and a grooved cavity section (12). The threaded cavity section (11) is used to connect with the external thread on the external connector. The grooved cavity section (12) has an upper groove (13) for the retaining ring installed on its cavity wall. When installed in place, the lower groove (22) of the retaining ring corresponds to the upper groove (13) of the retaining ring, and the retaining ring (5) is assembled in the lower groove (22) of the connecting nut and the upper groove (13) of the housing retaining ring. The first insulator (3) is made of polyetherimide. The first insulator (3) is an integral injection molded fan-shaped structure with four grooves of varying depths on both circular surfaces. The first insulator (3) is fitted onto the pin (4) through the central hole (31). The side step (32) of the first insulator (3) is in close contact with the first step surface (26). The material of the second insulator (7) is polyetherimide. The second insulator (7) has a disc structure with a central hole (71) in the center of the disc. There are six holes evenly distributed around the central hole (71) in a symmetrical manner. The cable core (112) is fitted through the central hole (71). The second insulator (7) is inserted into the sleeve (6) with a clearance fit. When installed in place, one side of the second insulator (7) is in close contact with the sleeve (6), and the other side is in close contact with the external cable end face (111). The pin (4) has a sequentially connected cylindrical step structure, which consists of a first stage (41), a second stage (42) and a pin tail section (43). The front end cylinder of the first stage (41) is designed according to the interface size requirements and is used to be inserted into the socket of an external connector for electrical connection. The first insulator (3) is installed on the second stage (42). A central hole (45) is dug at the bottom of the pin tail section (43). An observation hole (44) is dug on the side of the pin tail section (43). The core (112) of the radio frequency coaxial cable first passes through the central hole (71) of the second insulator (7) and then extends into the central hole (45) of the pin (4). The core (112) of the radio frequency coaxial cable is fixed to the pin (4) by welding. The observation hole (44) is used to observe the amount of solder. The amount of solder should fill the observation hole (44) and not protrude. The sleeve (6) contains a first cavity (61), a second cavity (62), and a third cavity (63) arranged sequentially inside. The first cavity (61) is an impedance compensation cavity, which plays an auxiliary coplanar compensation role. The second cavity (62) is a transmission cavity. The third cavity (63) is an insulator cavity, which is used to install the second insulator (7). When installed in place, the disc surface of the second insulator (7) is close to the step (64). The sleeve (6) is inserted into the fourth cavity (254) with a clearance fit. The first cavity (61) is close to the second step surface (27). The outer edge of the welding sleeve (8) is sequentially distributed with a first cylindrical section (81), a step (83) and a second cylindrical section (82). The inside of the welding sleeve (8) includes a first cavity (841) and a second cavity (842) arranged in sequence. The inner wall of the first cavity (841) of the welding sleeve is soldered to the outer cable metal shielding layer (113). The second cavity (842) is fitted onto the cable sheath. When installed in place, the front end of the welding sleeve (8) is in close contact with the third step surface (28) to limit the housing (2) and the fastening nut (9). The fastening nut (9) passes through the cable and is finally fitted onto the welding sleeve (8), which further fits one end of the radio frequency coaxial cable by welding; the outer edge of the fastening nut (9) includes a first end (91) and a second end (92) arranged in sequence; the first end (91) is provided with an external thread and the first end (91) is limited by a step (83); when installed in place, the first end (91) engages with the internal thread cavity section (257) and the front end face (93) of the fastening nut (9) is in close contact with the step (83); Its features include: The cable ends are stripped using a segmented stripping method, and the stripping dimensions must be matched with the dimensions of the pin, the second insulator, and the welding sleeve. After stripping the first section of outer sheath using a wire stripping machine, the first section is tinned. The tinning method for the first section is as follows: the first section is directly immersed in the tin pot and immersed for 8 seconds, so that an appropriate amount of tin is attached to the outer shielding mesh. This is sufficient for welding while avoiding excessive tin that could affect the installation of the solder sleeve. Cut the second outer sheath; the second outer sheath does not need to be peeled off, but is pushed directly to the position where the first section has been tinned, and the second shielding mesh is tinned; the tinning method for the second section is: directly use a soldering iron to apply tin so that a thin layer of solder is evenly coated on the surface; then remove the moved outer sheath; strip the wire core according to the wire stripping requirements, and wait for soldering; Secure the fastening nut to the cable end, and then spirally wrap the solder wire around the section where the shielding mesh has been removed. The adjacent loops should be tightly fitted together. Place the solder sleeve onto the cable with the solder wire wrapped around it, and make sure it is tightly fitted to the end face of the solder sleeve. Use a high-impedance soldering machine to solder the solder sleeve. Do not change the position of the solder sleeve and the solder wire during clamping. Then solder, and the soldering time should be controlled within 20 seconds. After the solder melts, it should flow into the gap between the solder sleeve and the cable shielding layer. Insert the snap ring into the snap ring groove of the housing, clamp the snap ring with round-nose pliers, and then use a wrench to put the connecting nut on the housing. Release the round-nose pliers, and the outer ring of the snap ring will fall into the snap ring groove of the connecting nut. When installed in place, the connecting nut can rotate freely on the housing without falling off. The first insulator is installed into the third cavity of the housing, and the sleeve is then installed into the fourth cavity. The second insulator is installed on the cable core, and solder is filled into the center hole of the pin. Then the core is inserted into the center hole of the pin, and the pin is soldered onto the cable core. The cable end, along with the installed fastening nut, solder sleeve, second insulator, and pin, is installed into the housing. The first end of the fastening nut is tightened into the threaded section inside the housing, and the tightened connector and cable connection are heat-shrinked with a heat-shrinkable sleeve. Once installed, the inner wall of the first cavity of the welding sleeve is soldered to the metal shielding layer of the cable. The first insulator is fitted onto the second step of the pin, and the second insulator is fitted onto the cable core. The cable core passes through the center hole of the pin, and the cable core and the pin are connected together by solder. The sleeve is installed in the fourth cavity of the housing. One side of the first insulator is in close contact with the first step surface inside the housing, and the other side is in close contact with the front end of the sleeve. The second insulator is installed in the third cavity of the sleeve, with one side in close contact with the sleeve step and the other side in close contact with the cable end face. The front end face of the welding sleeve is in close contact with the third step surface of the housing. The thread of the threaded cavity section of the housing mates with the external thread on the first end of the fastening nut. The snap ring is assembled in the lower and upper slots of the snap ring, and the connecting nut is fitted onto the housing through the snap ring. The cable sleeve covers the outside of the RF coaxial cable, the second end of the fastening nut, and the tail end of the housing.

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