Connection structure between high-frequency coaxial cable and coaxial connector

Abstract

To provide a connection structure between a high-frequency coaxial cable and a coaxial connector with excellent flexibility.SOLUTION: In a connection structure between a high-frequency coaxial cable 1 arranged with an insulator 6 around the outer periphery of a central conductor 5, and arranged with an outer conductor 7, and formed with a solder coat portion 7a by applying a solder coat to the outer conductor 7, and having a male screw portion 7b formed by threading the solder coating portion 7a, and a coaxial connector 2 having a center pin 5 and a body portion 8, to the high-frequency coaxial cable 1, a cylindrical shell 3 formed with a female threaded portion 3c that screws into the male threaded portion 7b is screwed and fixed, in the coaxial connector 2, an accommodating portion for accommodating the shell 3 is formed in the main body portion 8, and the shell 3 is accommodated in the accommodating portion and fixed by being clamped by a clamp 9. The solder coating portion 7a is configured so as not to protrude from the rear end of the shell 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a connection structure between a high-frequency coaxial cable and a coaxial connector.

Background Art

[0002] Conventionally, a connection structure between a high-frequency coaxial cable having a soldered tip portion of an outer conductor and subjected to spiral uneven processing and a coaxial connector has been known (Patent Document 1: Japanese Patent No. 4270489, Patent Document 2: Japanese Patent No. 4785184, Patent Document 3: Japanese Patent No. 6587412). As an example, the connection structure described in Patent Document 1 is configured to perform threading on a soldered outer conductor, screw it into a shell having a flange, and attach the shell to a coaxial connector body for electrical connection. As an example, the connection structure described in Patent Document 2 is configured to perform threading on a soldered outer conductor and screw it into a coaxial connector body for electrical connection. As an example, the connection structure described in Patent Document 3 is configured to perform threading on a sleeve fixed to a soldered outer conductor with solder, an adhesive, or the like, and screw the sleeve into a coaxial connector body for electrical connection. Here, the shell and the sleeve are synonymous. In addition to the above connection structures, there are known structures in which the outer conductor of the coaxial cable and the coaxial connector are clamped and fixed, and structures in which a cylindrical shell is fixed with solder and clamped with a clamp. These connection structures are implemented to ensure the required connection strength.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] High-frequency coaxial cables are used in high-frequency bands such as the microwave and millimeter-wave bands. Conventionally, connector termination work at the end of high-frequency coaxial cables has involved methods such as soldering the stripped outer conductor and simultaneously soldering it to the shell, or soldering the stripped outer conductor and then additionally soldering the base of the shell or connector body to fix the shell or connector body. When connector termination work is performed at the end of a high-frequency coaxial cable using these methods, when the shell or connector body is connected, the solder coat extends to the inside of the sheath of the high-frequency coaxial cable, and also to the outer conductor of the high-frequency coaxial cable outside the connector. As a result, solder rises to areas where it is not necessary, causing the high-frequency coaxial cable to become stiff and prone to breakage. [Means for solving the problem]

[0005] The present invention has been made in view of the above circumstances, and aims to provide a connection structure between a high-frequency coaxial cable and a coaxial connector that offers excellent flexibility.

[0006] As one embodiment, the above problem is solved by the solution disclosed below.

[0007] The connection structure between a high-frequency coaxial cable and a coaxial connector according to the present invention comprises a high-frequency coaxial cable having an insulator arranged on the outer circumference of a central conductor, an outer conductor arranged on the outer circumference of the insulator, a solder coating applied to the outer conductor to form a solder-coated portion, and a male screw portion formed by threading the solder-coated portion, and a coaxial connector having a center pin and a main body, wherein the high-frequency coaxial cable is fixed by screwing in a cylindrical shell having a female screw portion that screws into the male screw portion, the coaxial connector has a housing portion formed in the main body for housing the shell, the shell is housed in the housing portion and fixed by being clamped, and the solder-coated portion is of the shell The tip portion in the direction of screw connection to the aforementioned high-frequency coaxial cableIt is characterized by a configuration that does not protrude further.

[0008] This configuration allows for a configuration in which the solder coating is not applied to the bendable range of the high-frequency coaxial cable, resulting in a configuration with superior flexibility compared to conventional products. For example, the solder coating may extend beyond the front end of the shell. For example, a flange may be provided at the front end of the shell. For example, the solder coating may be contained within the shell.

[0009] The connection structure between a high-frequency coaxial cable and a coaxial connector according to the present invention is a connection structure between a high-frequency coaxial cable having an insulator arranged on the outer circumference of a central conductor, an outer conductor arranged on the outer circumference of the insulator, a solder coating applied to the outer conductor to form a solder-coated portion, and a male screw portion formed by threading the solder-coated portion, and a coaxial connector having a center pin and a main body, wherein the high-frequency coaxial cable is screwed into and fixed to the main body which has a female screw portion that screws into the male screw portion, and the solder-coated portion is the same as the main body The tip portion in the direction of screw connection to the aforementioned high-frequency coaxial cable It is characterized by a configuration that does not protrude further.

[0010] With this configuration, the solder-coated section is housed within the main body, and the solder coating is not applied to the bendable range of the high-frequency coaxial cable, resulting in a configuration with superior flexibility compared to conventional products.

[0011] In the solder-coated portion, the male screw portion preferably has a threaded groove formed with a depth ratio of 2% or more to the threaded outer diameter. Depending on the conditions of the spiral uneven processing of the tip of the outer conductor, the desired strength may not be achieved, but with this configuration, the necessary tensile strength can be ensured even in the case of a small-diameter high-frequency coaxial cable. The ratio is more preferably 4% or more. This allows for a significant improvement in tensile strength even in the case of a small-diameter high-frequency coaxial cable.

[0012] In the solder-coated portion, it is preferable that the male screw portion has a threaded groove formed therein with a depth ratio of 15% or less to the threaded outer diameter. Conventionally, depending on the conditions of the spiral uneven processing of the tip of the outer conductor, the outer conductor may be scratched and damaged, but with this configuration, damage to the outer conductor can be prevented more reliably. [Effects of the Invention]

[0013] According to the present invention, a connection structure with excellent flexibility can be realized in a connection structure between a high-frequency coaxial cable and a coaxial connector. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic diagram showing an example of a connection structure between a high-frequency coaxial cable and a coaxial connector according to the first embodiment of the present invention. [Figure 2] Figure 2A is a schematic cross-sectional view of a high-frequency coaxial cable according to the first embodiment; Figure 2B is a schematic cross-sectional view of the high-frequency coaxial cable in Figure 2A with the outer conductor soldered; Figure 2C is a schematic cross-sectional view showing the relationship between the threaded high-frequency coaxial cable in Figure 2B and the shell; and Figure 2D is a schematic cross-sectional view showing the relationship between the high-frequency coaxial cable in Figure 2C with the shell screwed in and fixed, and the coaxial connector. [Figure 3] Figure 3 is a schematic diagram showing an example of a connection structure between a high-frequency coaxial cable and a coaxial connector according to a second embodiment of the present invention. [Figure 4] Figure 4A is a schematic cross-sectional view of a high-frequency coaxial cable according to the second embodiment, Figure 4B is a schematic cross-sectional view of the high-frequency coaxial cable of Figure 4A with the outer conductor coated with solder, and Figure 4C is a schematic cross-sectional view showing the high-frequency coaxial cable of Figure 4B with threading and its relationship to a coaxial connector. [Figure 5] Figure 5 is a schematic diagram showing an example of a connection structure between a high-frequency coaxial cable and a coaxial connector according to a third embodiment of the present invention. [Figure 6]FIG. 6A is a schematic cross-sectional view of a high-frequency coaxial cable according to a third embodiment, FIG. 6B is a schematic cross-sectional view of the high-frequency coaxial cable of FIG. 6A in a state where the outer conductor is solder-coated, FIG. 6C is a schematic cross-sectional view showing the relationship between the threaded state of the high-frequency coaxial cable of FIG. 6B and the shell, and FIG. 6D is a schematic cross-sectional view showing the relationship between the state where the shell is screwed and fixed to the high-frequency coaxial cable of FIG. 6C and the coaxial connector. [Figure 7] FIG. 7A is a schematic structural view showing a first example of a high-frequency coaxial cable, FIG. 7B is a schematic structural view showing a second example of a high-frequency coaxial cable, FIG. 7C is a schematic structural view showing a third example of a high-frequency coaxial cable, and FIG. 7D is a schematic structural view showing a fourth example of a high-frequency coaxial cable.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As an example, the connection structure between the high-frequency coaxial cable and the coaxial connector in this embodiment is applied to a cable for signal transmission in the DC to millimeter-wave band. In all the drawings for explaining the embodiments, members having the same function may be denoted by the same reference numerals, and repeated explanations may be omitted.

[0016] [High-Frequency Coaxial Cable] The high-frequency coaxial cable 1 will be described below based on FIGS. 7A to 7D.

[0017] FIG. 7A shows a high-frequency coaxial cable 1A of the first example, in which a seamless metal tube 17 is provided on the outermost periphery to form an outer conductor 7. In addition to the above configuration, an insulating sheath 16 may be provided on the outer periphery of the metal tube 17.

[0018] FIG. 7B shows a high-frequency coaxial cable 1B of the second example, in which a braided wire 13 made of metal strands is provided on the outer periphery of the insulator 6 to form an outer conductor 7. An insulating sheath 16 is arranged on the outermost periphery.

[0019] Figure 7C shows a third example of a high-frequency coaxial cable 1C, in which a metal foil 11 is spirally wound around the outer circumference of an insulator 6, and a braided wire 13 made of metal strands is provided around the outer circumference of the metal foil 11 to form the outer conductor 7. An insulating sheath 16 is placed on the outermost circumference.

[0020] Figure 7D shows the fourth example of a high-frequency coaxial cable 1D, in which a metal foil 11 is spirally wound around the outer circumference of an insulator 6, a buffering resin tape 12 is spirally wound around the outer circumference of the metal foil 11, and a braided wire 13 made of metal strands is provided around the outer circumference of the resin tape 12 to form the outer conductor 7. An insulating sheath 16 is placed on the outermost circumference.

[0021] As an example of configurations other than those described above, the metal foil 11 may be attached vertically. As an example, it may be wound horizontally with metal wires. Therefore, the outer conductor 7 is constructed using a metal tube 17 provided on the outer circumference of the insulator 6, or a spirally wound or vertically attached metal foil 11, a cushioning resin tape 12, or a braided wire 13 made of metal wires or a horizontal winding of metal wires, or a combination of these.

[0022] As illustrated in Figure 1, the high-frequency coaxial cable 1 has a solder coating applied to the outer circumference of the connection end with the coaxial connector 2 on the outer conductor 7 to form a solder-coated portion 7a, and the solder-coated portion 7a is threaded to form a male screw portion 7b. When the outer conductor 7 is made of a metal tube, the male screw portion 7b is formed on the outer circumference while it is solder-coated. When the outer conductor 7 is made of spirally wound metal foil, braided wire made of metal strands, or a combination of these, the male screw portion 7b is formed on the outer conductor 7, which is solder-coated to form a single integrated structure. This stabilizes the shape of the male screw portion 7b and allows for sufficient tightening to bring the tip surface of the outer conductor 7 into close contact with the shell or the inner wall of the connector. As a result, structural dimensional continuity is ensured, and good high-frequency transmission characteristics and shielding characteristics are obtained.

[0023] The central conductor 5 may be, for example, a composite material such as copper or copper alloy, copper-clad steel wire, stainless steel, aluminum or aluminum alloy, or copper-clad aluminum, or a material plated with a highly conductive metal. For example, the central conductor 5 may be silver-plated soft copper wire or soft copper wire. The central conductor 5 may be a single wire or a stranded wire. Alternatively, the central conductor 5 may be a compressed conductor obtained by bundling multiple wires together and compressing them axially to create a roughly circular cross-section. For example, copper wire may be drawn to create a central conductor 5 with a circular or elliptical cross-section.

[0024] The insulator 6 is composed of one or more insulators, and examples include polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), polyethylene naphthalate (PEN), polyimide (PI), polyphenylene sulfide (PPS), ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), fluorinated resin copolymer (perfluoroalkoxy fluororesin: PFA), polyetheretherketone (PEEK), polyethylene terephthalate (PET), polyamide (PA), etc. When used in frequency bands exceeding 100 GHz, it is more preferable to be composed of an insulator with a low dielectric constant. Examples of low dielectric constant insulators 6 include porous PTFE and PTFE.

[0025] The outer conductor 7 is constructed using a metal tube 17 provided on the outer circumference of the insulator 6, or a spirally wound or longitudinally attached metal foil 11, a cushioning resin tape 12, or a braided wire 13 made of metal strands or a horizontally wound metal strand, or a combination of these.

[0026] The metal foil 11 is a conductive metal foil consisting of one or more layers. The metal foil 11 can be stainless steel, nickel alloy, copper or copper alloy, aluminum or aluminum alloy, or a composite material thereof, or a material such as one of these materials plated with a metal that has high conductivity and excellent solderability. The resin tape 12 is composed of one or more layers of insulator and is preferably formed on the outer surface of the metal foil 11 and self-fusing upon heating. The insulator constituting the resin tape 12 can be PEN, PPS, PET, PA, etc. The braided wire 13 is a braided wire made of conductive metal strands. The metal strands constituting the braided wire 13 can be stainless steel, nickel alloy, copper or copper alloy, aluminum or aluminum alloy, or a composite material thereof, or a material such as one of these materials plated with a metal that has high conductivity and excellent solderability.

[0027] As an example, the diameter of the outer conductor 7 in the high-frequency coaxial cable 1 is 0.5 to 7 mm, more preferably 2 to 7 mm. By making the diameter of the outer conductor 7 7 mm or less, a thin and flexible configuration is achieved, making it easy to accommodate miniaturized and high-density electronic devices. A diameter of 6 mm or less is more preferable. Furthermore, by making the diameter of the outer conductor 7 2 mm or more, the tensile strength required for use in electronic devices can be obtained.

[0028] The sheath 16 is an insulating outer layer that insulates the cable from the outside and constitutes the outermost layer of the high-frequency coaxial cable 1. The sheath 16 is, for example, made of FEP (fluoropolymer resin). Depending on the application, there are configurations with and without the sheath 16.

[0029] [First Embodiment] An example of a first embodiment of the connection structure between a high-frequency coaxial cable and a coaxial connector will be described below with reference to Figures 1 and 2A to 2D.

[0030] Figure 1 shows an example of a connection structure between a high-frequency coaxial cable 1, in which an insulator 6 is arranged around the outer circumference of a central conductor 5, an outer conductor 7 is arranged around the outer circumference of the insulator 6, a sheath 16 is arranged around the outermost circumference, a solder coating is applied to the outer conductor 7 to form a solder-coated portion 7a, and a screw-coated portion 7a is threaded to form a male screw portion 7b, and a coaxial connector 2 having a center pin 15 and a main body portion 8.

[0031] The high-frequency coaxial cable 1 has a male threaded portion 7b formed on the outer peripheral end of the outer conductor 7. The metal, cylindrical shell 3 has a female threaded portion 3c formed inside that corresponds to the male threaded portion 7b. The shell 3 is screwed into and fixed to the high-frequency coaxial cable 1. The coaxial connector 2 has a metal body 8 with a housing portion 8c formed inside that corresponds to the shell 3.

[0032] The main body 8 of the coaxial connector 2 has a center pin 15 on its internal tip side and a female thread 8d formed on its internal rear end side. The clamp 9 has a male thread 9d formed on its outer circumference at the tip side that engages with the female thread 8d. The rear end of the center pin 15 is shaped like a split pin, and as an example, the tip of the central conductor 5 is press-fitted into the rear end of the center pin 15 for connection. The shell 3 is made of composite materials such as copper or copper alloy, stainless steel, aluminum or aluminum alloy, copper-clad aluminum, or these materials plated with a highly conductive metal.

[0033] The solder-coated portion 7a is configured not to protrude beyond the rear end 3b of the shell 3. The male screw portion 7b has a groove G1 formed therein, with a depth ratio of 2 to 15% of the threaded outer diameter D1. The high-frequency coaxial cable 1 and the coaxial connector 2 are then screwed together and secured by a clamp 9 while the shell 3 is housed in the housing portion 8c.

[0034] Next, the manufacturing procedure of this embodiment will be described below with reference to Figures 2A to 2D.

[0035] First, the sheath 16 is stripped from the end of the high-frequency coaxial cable 1, as shown in Figure 2A, to expose the outer conductor 7. Then, a solder coating is applied to the tip of the exposed outer conductor 7 to form a solder-coated portion 7a as shown in Figure 2B. In the portion that will become the male screw portion 7b, the metal foil 11, resin tape 12, and braided wire 13 become an integrated structure due to the solder coating applied to the braided wire 13. The cable is immersed in a solder bath to apply the solder coating. For example, the temperature of the solder bath is adjusted to 320°C and the immersion time to approximately 2 seconds to ensure that the area of ​​the solder-coated portion 7a is within the specified range. At least the tip of the sheath 16 is left without the solder-coated portion 7a. Then, the tip of the solder-coated portion 7a and the tip of the insulator 6 are removed to expose the central conductor 5.

[0036] Next, the solder-coated portion 7a is subjected to rough male threading using a dedicated threading die to form the male thread portion 7b as shown in Figure 2C. A groove G1 is formed to form the male thread portion 7b, with a depth ratio of 2 to 15% of the threaded outer diameter D1. The shell 3 has a female thread portion 3c formed on its inner circumferential surface. Here, the threaded outer diameter D1 of the male thread portion 7b corresponds to the root diameter E1 of the female thread portion 3c, and the threaded root diameter D2 of the male thread portion 7b corresponds to the inner diameter E2 of the female thread portion 3c. Here, the front end 3a of the shell 3 is the starting end or the ending end of the female thread portion 3c. The solder-coated portion 7a is configured not to protrude beyond the rear end 3b of the shell 3. The solder-coated portion 7a may be configured to protrude beyond the front end 3a of the shell 3, or it may be configured not to protrude beyond the front end 3a of the shell 3.

[0037] Then, as shown in Figure 2D, the shell 3 is rotated and inserted into the high-frequency coaxial cable 1, which is inserted through the through hole 9c of the clamp 9, until it is screwed in and secured until the front end 3a of the shell 3 and the tip surface of the male screw portion 7b are flush, or until the tip surface of the male screw portion 7b protrudes from the front end 3a of the shell 3. The shell 3 has a flange-shaped receiving portion 3e that protrudes outward at a position in the middle of its outer circumference.

[0038] After integrating the high-frequency coaxial cable 1 and the shell 3 into a single structure, the front end 9a of the clamp 9 is brought into contact with the receiving portion 3e of the shell 3. The clamp 9 is then rotated and inserted into the main body portion 8 of the coaxial connector 2 until it is screwed in. The shell 3 is then housed in the housing portion 8c and secured by being clamped in place by the clamp 9. The screw tightening torque at this time causes the tip surface of the male screw portion 7b to press against the stepped portion of the inner wall of the main body portion 8, ensuring stable contact. This completes the connection structure between the high-frequency coaxial cable 1 and the coaxial connector 2, as shown in Figure 1.

[0039] [Second Embodiment] Next, an example of a second embodiment of the connection structure between a high-frequency coaxial cable and a coaxial connector will be described below based on Figures 3 and 4A to 4C.

[0040] Figure 3 shows an example of a connection structure between a high-frequency coaxial cable 1, in which an insulator 6 is arranged around the outer circumference of a central conductor 5, an outer conductor 7 is arranged around the outer circumference of the insulator 6, a sheath 16 is arranged around the outermost circumference, a solder coating is applied to the outer conductor 7 to form a solder-coated portion 7a, and a screw-coated portion 7a is threaded to form a male screw portion 7b, and a coaxial connector 2 having a center pin 15 and a main body portion 4.

[0041] The high-frequency coaxial cable 1 has a male threaded portion 7b formed on the outer peripheral end of the outer conductor 7. The metal body portion 4 has a female threaded portion 4c formed inside that corresponds to the male threaded portion 7b. The high-frequency coaxial cable 1 is screwed into and fixed to the body portion 4.

[0042] The main body 4 of the coaxial connector 2 has a center pin 15 on its internal tip side and a female screw portion 4c formed on its internal rear end side. The rear end of the center pin 15 is shaped like a split pin, and as an example, the tip of the central conductor 5 is press-fitted into the rear end of the center pin 15 for connection.

[0043] The solder-coated portion 7a is configured not to protrude beyond the rear end 4b of the main body portion 4. The male screw portion 7b has a groove G1 formed therein, with a depth ratio of 2 to 15% of the threaded outer diameter D1. The high-frequency coaxial cable 1 and the coaxial connector 2 are then screwed together and fixed in place.

[0044] Next, the manufacturing procedure of this embodiment will be described below with reference to Figures 4A to 4C.

[0045] First, the sheath 16 is stripped from the end of the high-frequency coaxial cable 1 in the state shown in Figure 4A to expose the outer conductor 7. Then, a solder coating is applied to the tip of the exposed outer conductor 7 to form a solder-coated portion 7a as shown in Figure 4B. As in the embodiment described above, the area of ​​the solder-coated portion 7a is kept within the specified range. Then, the tip of the solder-coated portion 7a and the tip of the insulator 6 are removed to expose the central conductor 5.

[0046] Next, the solder-coated portion 7a is subjected to rough male threading using a dedicated threading die to form the male thread portion 7b as shown in Figure 4C. Similar to the embodiment described above, the range of the male thread portion 7b is kept within the specified limits.

[0047] Then, as shown in Figure 4C, the main body 4 is rotated and inserted into the high-frequency coaxial cable 1 until it is screwed in and secured. The screw tightening torque at this time causes the tip surface of the male screw portion 7b to press against the stepped portion of the inner wall of the main body 4, ensuring stable contact. This completes the connection structure between the high-frequency coaxial cable 1 and the coaxial connector 2, as shown in Figure 3.

[0048] [Third Embodiment] An example of a third embodiment of the connection structure between a high-frequency coaxial cable and a coaxial connector will be described below with reference to Figures 5 and 6A to 6D.

[0049] Figure 5 shows an example of a connection structure between a high-frequency coaxial cable 1, in which an insulator 6 is arranged around the outer circumference of a central conductor 5, an outer conductor 7 is arranged around the outer circumference of the insulator 6, a sheath 16 is arranged around the outermost circumference, a solder coating is applied to the outer conductor 7 to form a solder-coated portion 7a, and a screw-coated portion 7a is threaded to form a male screw portion 7b, and a coaxial connector 2 having a center pin 15 and a main body portion 8.

[0050] The high-frequency coaxial cable 1 has a male threaded portion 7b formed on the outer peripheral end of the outer conductor 7. The metal, cylindrical shell 3 has a female threaded portion 3c formed inside that corresponds to the male threaded portion 7b. The shell 3 is screwed into and fixed to the high-frequency coaxial cable 1. The tip of the shell 3 has a flange 3d that extends inward. The main body 8 of the coaxial connector 2 is the same as in the first embodiment described above.

[0051] Next, the manufacturing procedure of this embodiment will be described below with reference to Figures 6A to 6D.

[0052] First, the sheath 16 is stripped from the end of the high-frequency coaxial cable 1 in the state shown in Figure 6A to expose the outer conductor 7. Then, a solder coating is applied to the tip of the exposed outer conductor 7 to form a solder-coated portion 7a as shown in Figure 6B. Similar to the embodiment described above, the area of ​​the solder-coated portion 7a is kept within the specified range. Then, the tip of the solder-coated portion 7a and the tip of the insulator 6 are removed to expose the central conductor 5.

[0053] Next, the solder-coated portion 7a is subjected to rough male threading using a dedicated threading die to form the male thread portion 7b as shown in Figure 6C. Similar to the embodiment described above, the range of the male thread portion 7b is kept within the specified limits. Here, the threaded outer diameter D1 in the male thread portion 7b corresponds to the root diameter E1 in the female thread portion 3c, and the threaded root diameter D2 in the male thread portion 7b corresponds to the inner diameter E2 in the female thread portion 3c. The inner diameter E3 of the flange 3d in the shell 3 is set to be smaller than the root diameter D2 in the male thread portion 7b.

[0054] Then, as shown in Figure 6D, the high-frequency coaxial cable 1 is inserted through the through-hole 9c of the clamp 9, and the shell 3 is rotated and inserted until the tip surface of the male screw portion 7b abuts against the inner wall of the flange 3d of the shell 3, thereby screwing in and connecting the high-frequency coaxial cable 1, and fixing the high-frequency coaxial cable 1 and the shell 3 as a single integrated structure.

[0055] After integrating the high-frequency coaxial cable 1 and the shell 3 into a single structure, the front end 9a of the clamp 9 is brought into contact with the receiving portion 3e of the shell 3. The clamp 9 is then rotated and inserted into the main body portion 8 of the coaxial connector 2 until it is screwed in. The shell 3 is then housed in the housing portion 8c and secured by being clamped in place by the clamp 9. The screw tightening torque at this time causes the front surface of the shell 3 to press against the stepped portion of the inner wall of the main body portion 8, ensuring stable contact. This completes the connection structure between the high-frequency coaxial cable 1 and the coaxial connector 2, as shown in Figure 5.

[0056] [Examples 1-4] Next, Examples 1 to 4 and Comparative Examples 1 to 3 of the connection structure between the high-frequency coaxial cable 1 and the coaxial connector 2 according to the first embodiment described above will be explained below.

[0057] As described above, the connection structure between the high-frequency coaxial cable 1 and the coaxial connector 2 is configured such that the solder-coated portion 7a does not protrude from the rear end of the shell 3. The outer conductor 7 at the end of the high-frequency coaxial cable 1 is exposed, and the exposed outer conductor 7 is coated with solder to form the solder-coated portion 7a. The thickness of the solder-coated portion 7a is 0.25 to 0.5 mm. Next, the solder-coated portion 7a is roughly threaded using a dedicated threading die to form the male threaded portion 7b. Then, when the spiral grooves are formed on the outer conductor 7, cuts are made to a depth within the range of 0.5 to 18% of the outer diameter of the outer conductor 7, resulting in Examples 1 to 4 and Comparative Examples 1 to 3, which differ in the cutting conditions. Then, the tip surface of the male threaded portion 7b abuts against the inner wall of the flange 3d of the shell 3 and the high-frequency coaxial cable 1 is screwed in and inserted until the high-frequency coaxial cable 1 and the shell 3 are integrated into a single structure.

[0058] For each sample, the end of the high-frequency coaxial cable 1 was fixed to one end of a tensile testing machine (single-column type material testing machine STA-1225), and the shell 3 was fixed to the other end of the tensile testing machine. The tensile strength required for the outer conductor 7 to break at a test speed of 200 mm / min was measured. The evaluation criteria were as follows: a tensile strength of 140 N or more was ranked A, a tensile strength of less than 140 N was ranked B, and the inability to attach the shell 3 was ranked C.

[0059] Table 1 shows the evaluation results of the tensile strength of each sample.

[0060] [Table 1]

[0061] As shown in Table 1, all of Examples 1 to 4 achieved a tensile strength of rank A, ensuring the required tensile strength of 140N or more. On the other hand, Comparative Example 1 had insufficient threading, resulting in a defective product with a tensile strength of rank C. Comparative Examples 2 and 3 had excessive threading, resulting in a tensile strength of rank B. Compared to the conventional technology, Examples 1 to 4 were found to have superior properties, ensuring physical strength against bending and twisting.

[0062] [Example 5] Next, Example 5 and Comparative Example 4 of the connection structure between the high-frequency coaxial cable 1 and coaxial connector 2 according to the first embodiment described above will be explained below.

[0063] The only difference between the components of Example 5 and those of Examples 1-4 is the change in outer diameter D1; the connection structure is the same. The same applies to Comparative Example 4.

[0064] For each sample, the end of the high-frequency coaxial cable 1 was fixed to one end of the tensile testing machine, and the coaxial connector 2 was fixed to the other end of the tensile testing machine. The tensile strength required for the outer conductor 7 to break at a test speed of 200 mm / min was measured. The evaluation criteria were as follows: a tensile strength of 270 N or more was ranked A, a tensile strength of less than 270 N was ranked B, and the inability to attach the coaxial connector 2 was ranked C.

[0065] Table 2 shows the evaluation results of the tensile strength of each sample.

[0066] [Table 2]

[0067] As shown in Table 2, Example 5 achieved a tensile strength of rank A, successfully securing the required tensile strength of 270N or more. On the other hand, Comparative Example 4 had excessive threading, resulting in a tensile strength of rank B.

[0068] [Example 6] Next, an embodiment 6 of the connection structure between the high-frequency coaxial cable 1 and the coaxial connector 2 according to the second embodiment described above will be explained below.

[0069] The connection structure between the high-frequency coaxial cable 1 and the coaxial connector 2 is as described above. The outer conductor 7 at the end of the high-frequency coaxial cable 1 is exposed, and a solder coating is applied to the exposed outer conductor 7 to form a solder-coated portion 7a. The thickness of the solder-coated portion 7a is 0.25 to 0.5 mm. Next, a rough male thread is formed on the solder-coated portion 7a using a dedicated threading die to form a male screw portion 7b. Then, when the spiral grooves are formed on the outer conductor 7, cuts are made to a depth within the range of 0.5 to 18% of the outer diameter of the outer conductor 7, resulting in a different cutting condition for Embodiment 6. The high-frequency coaxial cable 1 is then rotated and inserted into the coaxial connector 2 until the tip surface of the male screw portion 7b abuts against the inner wall and the high-frequency coaxial cable 1 is screwed in, thereby creating an integrated structure between the high-frequency coaxial cable 1 and the coaxial connector 2.

[0070] For each sample, the end of the high-frequency coaxial cable 1 was fixed to one end of the tensile testing machine, and the coaxial connector 2 was fixed to the other end of the tensile testing machine. The tensile strength required for the outer conductor 7 to break at a test speed of 200 mm / min was measured. The evaluation criteria were as follows: a tensile strength of 270 N or more was ranked A, a tensile strength of less than 270 N was ranked B, and the inability to attach the coaxial connector 2 was ranked C.

[0071] Table 3 shows the evaluation results of the tensile strength of each sample.

[0072] [Table 3]

[0073] As shown in Table 3, Example 6 has a tensile strength of rank A, and the required tensile strength of 270N or more is secured. Although there are differences in the components between Example 6 and Example 5, the main parts of the connection structure are the same. Since the outer diameter D1 of Example 6 and the outer diameter D1 of Example 5 are roughly the same, it can be concluded that the tensile strengths are roughly the same.

[0074] [Example 7] Next, an embodiment 7 of the connection structure between the high-frequency coaxial cable 1 and the coaxial connector 2 according to the first embodiment described above will be explained below.

[0075] The only difference between the components of Example 7 and those of Examples 1-4 is the change in outer diameter D1; the connection structure is the same.

[0076] For each sample, the end of the high-frequency coaxial cable 1 was fixed to one end of the tensile testing machine, and the coaxial connector 2 was fixed to the other end of the tensile testing machine. The tensile strength required for the outer conductor 7 to break at a test speed of 200 mm / min was measured. The evaluation criteria were as follows: a tensile strength of 245 N or higher was ranked A, a tensile strength of less than 245 N was ranked B, and the inability to attach the coaxial connector 2 was ranked C.

[0077] Table 4 shows the evaluation results of the tensile strength of each sample.

[0078] [Table 4]

[0079] As shown in Table 4, Example 7 has a tensile strength of rank A, and is able to secure the required tensile strength of 245N or more.

[0080] As described above, it has been confirmed that the required tensile strength can be secured even in the case of a small-diameter high-frequency coaxial cable 1 by forming a threaded groove G1 with a depth ratio of 2% or more to the threaded outer diameter D1. In addition, the threaded portion may be bonded with a resin adhesive such as a thermosetting adhesive in order to prevent the screw from loosening. Furthermore, as an example, a protective outer covering such as armor made of resin such as PVC or polyolefin may be attached. The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the present invention. [Explanation of Symbols]

[0081] 1. High-frequency coaxial cable 2 Coaxial connectors 3 Shell, 3a Front end, 3b Rear end, 3c Female threaded section, 3d Flange, 3e Receiving section 4 Main body, 4b rear end, 4c female screw part 5. Central conductor 6. Insulator 7 Outer conductor, 7a Solder-coated portion, 7b Male screw portion 8 Main body, 8c Storage section, 8d Female thread 9 clamp, 9a front end, 9c through hole, 9d male thread 11 Metal foil 12 Resin Tape 13 Braided wire 15 Center Pin 16 sheaths D1 Outer diameter D2 Valley diameter E1 Valley diameter E2 inner diameter E3 Inner diameter G1 groove

Claims

1. This is a connection structure between a high-frequency coaxial cable having a central conductor with an insulator arranged around its outer circumference, an outer conductor arranged around the insulator, a solder coating applied to the outer conductor to form a solder-coated portion, and a male screw portion formed by threading the solder-coated portion, and a coaxial connector having a center pin and a main body. The high-frequency coaxial cable is fixed by screwing in a cylindrical shell having a female screw portion that screws into the male screw portion, and the coaxial connector has a housing portion formed in the main body for housing the shell, and the shell housed in the housing portion is clamped and tightened to fix it in place. The solder-coated portion is configured so as not to protrude beyond the tip of the shell in the direction of screw connection to the high-frequency coaxial cable. A connection structure between a high-frequency coaxial cable and a coaxial connector, characterized by the following features.

2. The male screw portion in the solder-coated portion has a threaded groove formed therein, with a depth ratio of 2 to 15% of the threaded outer diameter. A connection structure for a high-frequency coaxial cable and a coaxial connector as described in claim 1, characterized by the above.

3. This is a connection structure between a high-frequency coaxial cable having a central conductor with an insulator arranged around its outer circumference, an outer conductor arranged around the insulator, a solder coating applied to the outer conductor to form a solder-coated portion, and a male screw portion formed by threading the solder-coated portion, and a coaxial connector having a center pin and a main body. The high-frequency coaxial cable is screwed into and fixed to the main body, which has a female screw portion that screws into the male screw portion. The solder-coated portion is configured so as not to protrude beyond the tip of the main body in the direction of screw connection to the high-frequency coaxial cable. A connection structure between a high-frequency coaxial cable and a coaxial connector, characterized by the following features.

4. The male screw portion in the solder-coated portion has a threaded groove formed therein, with a depth ratio of 2 to 15% of the threaded outer diameter. A connection structure for a high-frequency coaxial cable and a coaxial connector as described in claim 3, characterized by the above.

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