Insulated wire, cable, method for manufacturing insulated wire, and connection structure

Abstract

The present invention provides an insulated wire with stabilized properties by suppressing fluctuations in the elongation at break of the insulator, a cable comprising multiple insulated wires, a method for manufacturing an insulated wire, and a connection structure using an insulated wire. [Solution] The insulated wires 1A, 1B, and 1C each comprise a conductor 11 and a fluororubber insulator 13 covering the conductor 11. The water content of the insulator 13 is 0.4 wt% or less. Cable 1 is constructed by covering multiple insulated wires 1A, 1B, and 1C together with a sheath 102. The manufacturing method for the insulated wires 1A, 1B, and 1C comprises an insulator forming step of forming the insulator 13 by extruding a rubber material around the conductor 11 and crosslinking it, and a drying step of drying the insulator 13 formed in the insulator forming step to reduce the water content of the insulator 13 to 0.4 wt% or less.

Description

Technical Field

[0001] The present invention relates to an insulated wire in which a conductor is directly or indirectly coated with an insulator, a cable having a plurality of insulated wires, a method for manufacturing an insulated wire, and a connection structure using the insulated wire.

Background Art

[0002] Conventionally, for example, some cables used in a high-temperature environment such as an engine room of a vehicle have insulated wires in which a conductor is coated with an insulator made of fluorine rubber having excellent heat resistance (see, for example, Patent Documents 1 and 2).

[0003] When manufacturing such an insulated wire, a rubber material is extruded around a conductor and crosslinked, and then cooled. In the process of crosslinking the rubber material, the rubber material before crosslinking is continuously supplied into a crosslinking cylinder together with the conductor, and superheated steam is supplied into the crosslinking cylinder to directly contact the rubber material with the superheated steam to perform crosslinking.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When a heat aging test is performed on the insulated wire manufactured as described above, the elongation at break, which is one of the mechanical properties of the insulator, may vary greatly before and after the heat aging test. The inventors of the present invention have intensively studied the cause and found that the change in the amount of moisture contained in the insulator is involved in the variation of the elongation at break of the insulator, and thus the present invention has been completed. That is, an object of the present invention is to suppress the variation of the elongation at break of the insulator of the insulated wire and to stabilize the characteristics. [Means for solving the problem]

[0006] The present invention aims to solve the above problems by providing an insulated electric wire comprising a conductor and a fluororubber insulator that directly or indirectly covers the conductor, wherein the water content of the insulator is 0.4 wt% or less.

[0007] Furthermore, the present invention aims to solve the above problems by providing a cable in which a plurality of insulated wires are collectively covered with a sheath, wherein the insulated wires comprise a conductor and a fluororubber insulator that directly or indirectly covers the conductor, and the water content of the insulator is 0.4 wt% or less.

[0008] Furthermore, the present invention aims to solve the above problems and provides a method for manufacturing an insulated electric wire comprising a conductor and a fluororubber insulator that directly or indirectly covers the conductor, comprising an insulator forming step of forming the insulator by extruding a rubber material around the conductor and crosslinking it, and a drying step of drying the insulator formed in the insulator forming step to reduce the moisture content of the insulator to 0.4 wt% or less.

[0009] Furthermore, the present invention aims to solve the above problems by providing a connection structure for connecting a pair of devices using the above-mentioned insulated wire, wherein at least one of the pair of devices is used in a high-temperature environment, a terminal is fitted to the conductor at the end of the insulated wire, and the terminal is connected to the at least one of the devices.

[0010] Furthermore, the present invention aims to solve the above problems by providing a connection structure for connecting a pair of devices using the above-mentioned insulated wire, wherein the insulated wire is laid in an environment where it is immersed in high temperature, high radiation, high temperature steam, or cutting oil, a terminal is fitted to the conductor at the end of the insulated wire, and the terminal is connected to either of the pair of devices. [Effects of the Invention]

[0011] According to the present invention, fluctuations in the break elongation of the insulator of an insulated electric wire can be suppressed, and the properties of the insulator can be stabilized. [Brief explanation of the drawing]

[0012] [Figure 1] (a) is a perspective view showing a cable according to a first embodiment of the present invention. (b) is a cross-sectional view of the cable in line AA of (a). [Figure 2] (a) is a perspective view showing one of the three insulated wires. (b) is a cross-sectional view of the insulated wire in the BB wire shown in (a). [Figure 3] This is a schematic diagram showing an example of the configuration of a manufacturing apparatus that forms an insulator covering a conductor together with separator tape. [Figure 4] This graph shows an example of the change in the moisture content of the insulation in an insulated wire. [Figure 5] This graph shows an example of the change in the elongation of the insulation in an insulated wire. [Figure 6] This is a diagram showing a connection structure in which a pair of devices are connected by an insulated wire. [Figure 7] (a) is a perspective view showing a cable according to a second embodiment of the present invention. (b) is a cross-sectional view of the cable in the CC line of (a). [Figure 8] This is a cross-sectional view of a copper wire. [Figure 9] This is a diagram showing a connection structure in which a pair of devices are connected by an insulated wire. [Figure 10] This is a cross-sectional view of a cable having an insulated wire, which is a modified example in which the conductor configuration of the insulated wire of the cable according to the second embodiment has been modified. [Modes for carrying out the invention]

[0013] [First Embodiment] A first embodiment, which is a specific example of the present invention, will be described with reference to FIGS. 1 to 5. FIG. 1(a) is a perspective view showing a cable 1 according to the first embodiment of the present invention. FIG. 1(b) is a cross-sectional view of the cable 1 taken along line A-A in FIG. 1(a). This cable 1 is used, for example, in a high-temperature environment such as an engine room of a vehicle.

[0014] The cable 1 has a cable core 100 formed by twisting a plurality of insulated electric wires 1A, 1B, and 1C, a tape member 101 spirally wound around the cable core 100, and a sheath 102 covering the outer periphery of the tape member 101. As the tape member 101, for example, a belt-like one made of non-woven fabric, paper, or resin can be used. The sheath 102 is made of, for example, an ethylene-propylene copolymer and covers the plurality of insulated electric wires 1A, 1B, and 1C collectively. In addition, an intervening layer made of, for example, polypropylene yarn, spun yarn (rayon staple fiber), aramid fiber, nylon fiber, etc. may be arranged around the insulated electric wires 1A, 1B, and 1C.

[0015] In the present embodiment, the cable 1 has three insulated electric wires 1A, 1B, and 1C. The insulated electric wires 1A, 1B, and 1C each have a conductor 11, a separator layer 12, and an insulator 13 constituting an insulating layer that is the outermost layer. The separator layer 12 is provided between the conductor 11 and the insulator 13. That is, in the present embodiment, the insulator 13 indirectly covers the conductor 11 via the separator layer 12, and is configured such that the insulator 13 does not contact the conductor 11.

[0016] FIG. 2(a) is a perspective view showing one of the three insulated electric wires 1A, 1B, and 1C, which is the insulated electric wire 1A. FIG. 2(b) is a cross-sectional view of the insulated electric wire 1A taken along line B-B in FIG. 2(a). The insulated electric wires 1B and 1C are also configured in the same manner as the insulated electric wire 1A.

[0017] The conductor cross-sectional area of the conductor 11 is, for example, 38 mm 2This concludes the explanation. In this embodiment, the conductor 11 is a stranded wire made by twisting together multiple copper strands 111. As the copper strands 111, for example, soft copper wire, hard copper wire, or tin-containing copper alloy wire can be used. In the example shown in Figure 2, the conductor 11 has 43 copper strands 111, but the number of copper strands 111 is not limited to this, and the conductor 11 can be made up of an appropriate number of copper strands 111 depending on the application of the cable 1, etc.

[0018] The separator layer 12 is formed by a separator tape 120. The separator tape 120 is in the shape of a strip and is wound spirally around the conductor 11. Alternatively, the separator tape 120 may be wound longitudinally along the length of the conductor 11. The separator tape 120 is made of a water-free fluororesin. Specifically, this fluororesin can be, for example, PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane), or FEP (perfluoroethylene propene copolymer).

[0019] The insulator 13 is made of fluororubber and is extruded onto the outer circumference of the separator layer 12. Generally, fluororubber used as an insulator for insulated wires contains trace amounts of moisture due to superheated steam used in the manufacturing process. However, in this embodiment, the moisture content of the insulator 13 after manufacturing of insulated wires 1A, 1B, and 1C is lower than that of typical fluororubber insulators, being between 0.1 wt% and 0.4 wt%. The manufacturing method of insulated wires 1A, 1B, and 1C, including the molding method of the insulator 13, will be described later. A Karl Fischer moisture meter or a halogen moisture meter can be used to measure the moisture content of the insulator 13.

[0020] A heat aging test was performed on the manufactured insulated wires 1A, 1B, and 1C by holding them at 250°C for 96 hours. After that, the insulated wires 1A, 1B, and 1C were left in an environment at room temperature and 50% humidity for 24 hours, and the moisture content of the insulator 13 was between 0.2 wt% and 0.5 wt%. By leaving the insulated wires 1A, 1B, and 1C in an environment at room temperature and 50% humidity for 24 hours, the insulator 13 absorbs moisture, and the moisture content of the insulator 13 increases.

[0021] If we define E1 as the elongation of the insulator 13 of insulated wires 1A, 1B, and 1C after manufacturing and before the heat aging test, and E2 as the elongation of the insulator 13 after leaving the insulated wires 1A, 1B, and 1C for 24 hours in an environment with 50% humidity at room temperature after the heat aging test in which they are held at a temperature of 250°C for 96 to 672 hours, then the value of E2 / E1, which is the quotient obtained by dividing E2 by E1, is 0.65 or greater. In other words, whether they are held at a temperature of 250°C for 96 hours or 250°C for 672 hours, if we define E2 as the elongation of the insulator 13 after leaving the insulated wires 1A, 1B, and 1C for 24 hours in an environment with 50% humidity at room temperature, then the value of E2 / E1 is 0.65 or greater. Here, "elongation" refers to the elongation at break, which is the permanent elongation after rupture, expressed as a percentage of the gauge length, obtained by pulling the insulator 13 of the insulated wires 1A, 1B, and 1C, with the conductors 11 and separator tape 120 removed, in the longitudinal direction.

[0022] Furthermore, when the elongation of the insulator 13 after a heating aging test in which it is held at 250°C for 96 hours and then left in an environment with 50% humidity at room temperature for 24 hours is defined as E3, it is desirable that the value of E3 / E1 be 0.80 or greater, and the insulator 13 of the insulated wires 1A, 1B, and 1C according to this embodiment satisfies this criterion (E3 / E1≧0.80).

[0023] Next, the manufacturing method of insulated wires 1A, 1B, and 1C will be described. The manufacturing method of insulated wires 1A, 1B, and 1C includes an insulation forming step in which an insulator 13 is formed by extruding a rubber material around a conductor 11 and crosslinking it, and a drying step in which the insulator 13 formed in the insulation forming step is dried to reduce the moisture content of the insulator 13 to 0.4 wt% or less. After that, the manufactured insulated wires 1A, 1B, and 1C are twisted together to form a cable core 100, a tape member 101 is wrapped around the cable core 100, and the outer circumference of the tape member 101 is covered with a sheath 102 to obtain a cable 1.

[0024] Figure 3 is a schematic diagram showing an example of the configuration of a manufacturing apparatus 2 used in the insulator formation process. The manufacturing apparatus 2 includes an extrusion molding apparatus 21 for extruding rubber material that will become a fluororubber insulator 13, a crosslinking cylinder 22 for crosslinking the extruded rubber material by heating it, and a cooling cylinder 23 provided continuously with the crosslinking cylinder 22, thereby forming an insulator 13 that covers the conductor 11 together with the separator tape 120.

[0025] In the extrusion molding apparatus 21, the conductor 11 covered with separator tape 120 is continuously fed out, and rubber material that will become an insulator 13 is continuously extruded around it. The conductor 11, separator tape 120, and rubber material fed out from the extrusion molding apparatus 21 are continuously supplied into the crosslinking cylinder 22. Superheated steam is supplied into the crosslinking cylinder 22, and the rubber material is heated and crosslinked by the superheated steam coming into direct contact with it. In the cooling cylinder 23, the crosslinked rubber material is cooled, for example, with cooling water.

[0026] The temperature during crosslinking by this manufacturing apparatus 2 is, for example, 190 ± 20°C. The separator tape 120 prevents the surface of the copper wire 111 from oxidizing due to heat when superheated steam comes into contact with the conductor 11. The moisture content of the insulator 13 of the insulated wires 1A, 1B, and 1C immediately after being removed from the manufacturing apparatus 2 is, for example, 0.45 ± 0.05%. 1A, 1B, and 1C removed from the manufacturing apparatus 2 are sent to the drying process.

[0027] The drying process is carried out by one of the following three methods: Method 1 is drying in a hot air circulating drying oven or room at 80°C or higher for four days or more. Method 2 is drying by placing the product in a sealed container such as a desiccator containing a moisture absorbent such as silica gel. Method 3 is vacuum drying using a pressure-adjustable constant-temperature bath. These methods may also be combined to carry out the drying process.

[0028] Hereinafter, the state of the insulator 13 when the drying process is completed will be referred to as the initial state, the amount of water content of the insulator 13 in the initial state will be referred to as the initial water content, and the elongation of the insulator 13 in the initial state (E1 above) will be referred to as the initial elongation. The initial elongation is, for example, 395 (%). The initial water content is, for example, 0.28 ± 0.05 wt%.

[0029] Figure 4 is a graph showing the initial moisture content (average value) of the insulator 13 of insulated wires 1A, 1B, and 1C, and the change in the moisture content (average value) of the insulator 13 after a heat aging test was performed on the manufactured insulated wires 1A, 1B, and 1C by holding them at 250°C for 96 hours, followed by leaving the insulated wires 1A, 1B, and 1C in an environment at room temperature and 50% humidity for 4 hours, 24 hours, and 48 hours. Figure 5 is a graph showing the initial elongation (average value) of the insulator 13 of insulated wires 1A, 1B, and 1C, and the change in the elongation (average value) of the insulator 13 after a heat aging test was performed on the manufactured insulated wires 1A, 1B, and 1C by holding them at 250°C for 96 hours, followed by leaving the insulated wires 1A, 1B, and 1C in an environment at room temperature and 50% humidity for 4 hours, 24 hours, and 48 hours.

[0030] As shown in Figure 4, the moisture content of the insulator 13 decreases after the heat aging test, and then increases when placed in an environment with 50% humidity at room temperature. After 24 hours, the moisture content of the insulator 13 becomes approximately constant. Also, as shown in Figure 5, the elongation of the insulator 13 decreases initially after the heat aging test, similar to the moisture content, but recovers when placed in an environment with 50% humidity at room temperature. After 24 hours, the elongation of the insulator 13 becomes approximately constant.

[0031] Here, if the initial moisture content of the insulator 13 is greater than 0.4 wt%, the ratio of the initial elongation and the moisture content and elongation of the insulator 13 after the heat aging test to the initial moisture content will be large, and the ratio of the elongation of the insulator 13 after 4 hours, 24 hours, and 48 hours of the heat aging test to the initial elongation may fall below 0.8 and 0.65, respectively.

[0032] In contrast, in this embodiment, by setting the initial water content to 0.4 wt% or less, the E2 / E1 value becomes 0.65 or higher, and the E3 / E1 value becomes 0.8 or higher, thereby suppressing fluctuations in the elongation of the insulator 13 of the insulated wires 1A, 1B, and 1C after manufacturing. In other words, it is possible to suppress changes in the properties of the insulator 13 due to the surrounding environment after manufacturing and stabilize the properties of the insulator 13.

[0033] Figure 6 is a diagram illustrating an example of a connection structure that connects a pair of devices 4 and 5 using insulated wires 1A, 1B, and 1C. The devices 4 and 5 are, for example, a motor, inverter, control device, actuator, transformer, power supply, etc. The insulated wires 1A, 1B, and 1C have both longitudinal ends leading out from the sheath 102, and terminals 61 are fitted to the conductors 11 at the ends of the insulated wires 1A, 1B, and 1C, respectively.

[0034] Device 4 has a terminal block 40 having first to third washers 41 to 43. Similarly, Device 5 also has a terminal block 50 having first to third washers 51 to 53. Insulated wire 1A connects the first washer 41 of terminal block 40 of device 4 to the first washer 51 of terminal block 50 of device 5. Insulated wire 1B connects the second washer 42 of terminal block 40 of device 4 to the second washer 52 of terminal block 50 of device 5. Insulated wire 1C connects the third washer 43 of terminal block 40 of device 4 to the third washer 53 of terminal block 50 of device 5. Multiple terminals 61 are fixed to terminal blocks 40 and 50 respectively by screws 62.

[0035] Next, the environment in which this connection structure is used will be described. One example of this environment is one in which at least one of the devices 4 and 5 is used in a high-temperature environment, for example, of 60°C or higher. Another example of this environment is one in which the insulated wires 1A, 1B, and 1C are laid in an environment where they are immersed in high temperature, high radiation, high-temperature steam, or cutting oil. Even when used in such environments, the insulated wires 1A, 1B, and 1C of this embodiment suppress fluctuations in the elongation of the insulator 13 and stabilize the characteristics of the insulator 13.

[0036] In Figure 6, terminal 61 is shown connected to the first to third washers 41-43 and 51-53 of the terminal blocks 40 and 50 of equipment 4 and 5. However, the connection is not limited to this, and the conductors 11 of the insulated wires 1A, 1B, and 1C may also be connected to equipment 4 and 5 by connectors. In this case, the terminals of the connector (connector terminals) are fitted to the ends of the conductors 11 of the insulated wires 1A, 1B, and 1C.

[0037] [Second Embodiment] Next, a second embodiment of the present invention will be described with reference to Figures 7 to 9. Figure 7(a) is a perspective view showing a cable 3 according to the second embodiment of the present invention. Figure 7(b) is a cross-sectional view of the cable 3 along the CC line in Figure 7(a). This cable 3, like the cable 1 according to the first embodiment, is used in high-temperature environments such as the engine compartment of a vehicle.

[0038] Cable 3 has a cable core 300 formed by twisting together multiple insulated wires 3A and 3B, and a sheath 301 covering the cable core 300. The sheath 301 is made of, for example, an ethylene propylene copolymer and covers the multiple insulated wires 3A and 3B together. In this embodiment, cable 3 has a pair of insulated wires 3A and 3B, and the insulated wires 3A and 3B constitute a twisted pair wire. Note that intervening materials may be placed around the insulated wires 3A and 3B.

[0039] The insulated wires 3A and 3B comprise a conductor 31 and a fluororubber insulator 32 that directly covers the conductor 31. The conductor 31 is a stranded wire made by twisting together multiple copper strands (plated copper strands) 310 whose surfaces are tin-plated or silver-plated. In the example shown in Figure 7, the conductor 31 has 47 copper strands 310, but the number of copper strands 310 is not limited to this, and the conductor 31 can be composed of an appropriate number of copper strands 310 depending on the application of the cable 3. The conductor cross-sectional area of ​​the conductor 31 is, for example, 5.5 mm². 2 The following applies:

[0040] The insulated wires 3A and 3B are manufactured by a manufacturing method having an insulator formation step and a drying step, similar to the insulated wires 1A, 1B, and 1C according to the first embodiment, and the insulator 32 is formed by the manufacturing apparatus 2. The moisture content (initial moisture content) and elongation (initial elongation) of the insulator 32 after manufacturing of the insulated wires 3A and 3B are the same as the initial moisture content and initial elongation of the insulator 13 according to the first embodiment. Furthermore, after a heat aging test in which the wires 3A and 3B are held at 250°C for 96 hours, and then left in an environment with 50% humidity at room temperature for 24 hours, the moisture content of the insulator 32 is 0.2 wt% or more and 0.5 wt% or less.

[0041] In this embodiment, if the initial elongation of the insulator 32 is E1, and the elongation of the insulator 32 after leaving the insulated wires 3A and 3B for 24 hours in an environment with 50% humidity at room temperature after a heat aging test in which they are held at a temperature of 250°C for 96 to 672 hours after manufacturing is E2, then the value of E2 / E1 is 0.65 or more. Furthermore, if the elongation of the insulator 32 after leaving the insulated wires 3A and 3B for 24 hours in an environment with 50% humidity at room temperature after a heat aging test in which they are held at a temperature of 250°C for 96 hours after manufacturing is E3, then the value of E3 / E1 is 0.80 or more.

[0042] Figure 8 is a cross-sectional view of the copper wire 310. The copper wire 310 has a wire body 311 made of soft copper wire, hard copper wire, or tin-containing copper alloy wire, and a plating layer 312 formed to cover the surface 311a of the wire body 311. The plating layer 312 is a tin plating layer made of tin, or a silver plating layer made of silver. The plating layer 312 prevents the surface 311a of the wire body 311 from oxidizing due to the heat generated during crosslinking in the manufacturing process of the insulator 32.

[0043] In this second embodiment, as in the first embodiment, fluctuations in the elongation of the insulator 32 of the insulated wires 3A and 3B after manufacturing are suppressed, and changes in the characteristics of the insulator 32 due to the surrounding environment after manufacturing are suppressed.

[0044] Figure 9 is a diagram illustrating an example of a connection structure that connects a pair of devices 7 and 8 using insulated wires 3A and 3B. The devices 7 and 8 are, for example, electronic devices such as sensors, actuators, or control devices. The insulated wires 3A and 3B have both ends in the longitudinal direction leading out from the sheath 301. Terminals 911 are fitted to the conductors 31 at one end in the longitudinal direction of the insulated wires 3A and 3B, and these terminals 911 are held in the connector housing 912. Terminals 921 are fitted to the conductors 31 at the other end in the longitudinal direction of the insulated wires 3A and 3B, and these terminals 921 are held in the connector housing 922.

[0045] Multiple terminals 911 and a connector housing 912 constitute a first connector 91. The first connector 91 is mated to the device-side connector 71 of the device 7, and the multiple terminals 911 are connected to each other. The device-side connector 71 has multiple terminals 711 and a connector housing 712 that holds the multiple terminals 711.

[0046] Multiple terminals 921 and a connector housing 922 constitute a second connector 92. The second connector 92 is mated to the device-side connector 81 of the device 8, and the multiple terminals 921 are connected to the terminals 811 of the connector 81, respectively. The device-side connector 81 has multiple terminals 811 and a connector housing 812 that holds the multiple terminals 811.

[0047] One example of an environment in which this connection structure is used is an environment in which at least one of the devices 7 and 8 is used in a high-temperature environment, for example, at 60°C or higher. Another example of such an environment is an environment in which the insulated wires 3A and 3B are laid in an environment where they are immersed in high temperature, high radiation, high-temperature steam, or cutting oil. Even when used in such environments, the insulated wires 3A and 3B of this embodiment suppress fluctuations in the elongation of the insulator 32 and stabilize the characteristics of the insulator 32.

[0048] [Modified version of the second embodiment] Figure 10 is a cross-sectional view of a cable 30 having insulated wires 3C and 3D, which are modified versions of the conductor 31 configuration in the insulated wires 3A and 3B of the cable 3 according to the second embodiment. These insulated wires 3C and 3D are twisted together to form a cable core 302 and are collectively covered by a sheath 301. The insulated wires 3C and 3D are manufactured by the same manufacturing method as the insulated wires 1A, 1B, and 1C according to the first embodiment and the insulated wires 3A and 3B according to the second embodiment, and the insulator 32 of the insulated wires 3C and 3D has the same characteristics as the insulator 32 of the insulated wires 3A and 3B according to the second embodiment.

[0049] The conductor 33 of the insulated wire 3C, 3D is a compressed stranded wire made by twisting together multiple copper strands 330. The conductor cross-sectional area of ​​the conductor 33 is, for example, 5.5 mm². 2 The following applies. In Figure 10, as an example, the conductor 33 is composed of 17 copper strands 330, with 6 copper strands 330 arranged around one copper strand 330 located in the center, and 10 more copper strands 330 arranged around these 6 copper strands 330. However, the number and arrangement of the copper strands 330 are not limited to those exemplified in Figure 10, and can be appropriately changed depending on the application of the cable 30.

[0050] In the insulated wires 3C and 3D according to this modified example, the multiple copper wires 330 are compressed and tightly packed together, which prevents the superheated steam used to form the insulator 32 from entering the center of the conductor 33 through the gaps between the multiple copper wires 330. This suppresses oxidation of the surface of the copper wires 330 due to the heat of the superheated steam. Alternatively, the copper wires 330 may be plated copper wires having a tin plating layer or a silver plating layer. In this case, the compression of the copper wires 330 and the presence of a plating layer further suppress oxidation of the surface due to the heat of the superheated steam.

[0051] (Summary of the embodiments) Next, the technical concept understood from the embodiments described above will be described using the reference numerals and other symbols from the embodiments. However, the reference numerals in the following description are not limited to the components in the claims that are specifically shown in the embodiments.

[0052] [1] Insulated electric wire (1A, 1B, 1C, 3A, 3B, 3C, 3D) comprising a conductor (11, 31, 33) and a fluororubber insulator (13, 32) that directly or indirectly covers the conductor (11, 31, 33), wherein the water content of the insulator (13, 32) is 0.4 wt% or less.

[0053] [2] The insulated wire (1A, 1B, 1C, 3A, 3B, 3C, 3D) described in [1] above, wherein the moisture content of the insulator (13, 32) after being left for 24 hours in an environment of 50% humidity at room temperature after a heat aging test in which it is held at 250°C for 96 hours is 0.2 wt% or more and 0.5 wt% or less.

[0054] [3] When the initial elongation of the insulator (13,32) is E1, and the elongation of the insulator (13,32) after a heating aging test in which it is held at 250°C for 96 to 672 hours is E2, the value of E2 / E1 is 0.65 or greater, as described in [1] or [2] above, the insulated wire (1A,1B,1C,3A,3B,3C,3D).

[0055] [4] When the initial elongation of the insulator (13,32) is E1, and the elongation of the insulator (13,32) after a heating aging test in which it is held at 250°C for 96 hours is E3, the value of E3 / E1 is 0.80 or more, as described in [1] or [2] above, the insulated wire (1A,1B,1C,3A,3B,3C,3D).

[0056] [5] The insulated wire (3A, 3B) described in [1] above, wherein the conductor (31) is a stranded wire made by twisting together a plurality of tin-plated or silver-plated copper wires (310).

[0057] [6] The insulated wire (3C, 3D) described in [1] or [5] above, wherein the conductor (33) is a compressed stranded wire obtained by twisting together a plurality of copper strands (330) and compressing them.

[0058] [7] An insulated wire (1A, 1B, 1C) according to [1] or [5] above, wherein a separator layer (12) formed by a separator tape (120) made of fluororesin is provided between the conductor (11) and the insulator (13).

[0059] [8] A cable (1,3,30) comprising a plurality of insulated wires (1A,1B,1C,3A,3B,3C,3D) collectively covered by a sheath (102,301), wherein the insulated wires (1A,1B,1C,3A,3B,3C,3D) each comprise a conductor (11,31,33) and a fluororubber insulator (13,32) that directly or indirectly covers the conductor (11,31,33), and the water content of the insulator (13,32) is 0.4 wt% or less.

[0060] [9] A method for manufacturing an insulated electric wire (1A, 1B, 1C, 3A, 3B, 3C, 3D) comprising conductors (11, 31, 33) and fluororubber insulators (13, 32) that directly or indirectly cover the conductors (11, 31, 33), comprising: an insulator forming step of forming the insulators (13, 32) by extruding a rubber material around the conductors (11, 31, 33) and crosslinking it; and a drying step of drying the insulators (13, 32) formed in the insulator forming step to reduce the water content of the insulators (13, 32) to 0.4 wt% or less.

[0061]

[10] A connection structure for connecting a pair of devices (4, 5 / 7, 8) by the insulated wire (1A, 1B, 1C, 3A, 3B, 3C, 3D) described in [1] above, wherein at least one of the pair of devices (4, 5 / 7, 8) is used in a high-temperature environment, and terminals (61, 911, 921) are fitted to the conductors (13, 32) at the ends of the insulated wire (1A, 1B, 1C, 3A, 3B, 3C, 3D), and the terminals (61, 911, 921) are connected to at least one of the devices.

[0062]

[11] A connection structure for connecting a pair of devices (4, 5 / 7, 8) by insulated wires (1A, 1B, 1C, 3A, 3B, 3C, 3D) as described in [1] above, wherein the insulated wires (1A, 1B, 1C, 3A, 3B, 3C, 3D) are laid in an environment where they are immersed in high temperature, high radiation, high temperature steam, or cutting oil, terminals (61, 911, 921) are fitted to the conductors (13, 32) at the ends of the insulated wires (1A, 1B, 1C, 3A, 3B, 3C, 3D), and the terminals (61, 911, 921) are connected to either of the pair of devices (4, 5 / 7, 8).

[0063] Although embodiments of the present invention have been described above, these embodiments do not limit the invention as defined in the claims. Furthermore, it should be noted that not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention.

[0064] Furthermore, the present invention can be implemented with appropriate modifications without departing from its spirit. For example, although the above embodiment describes a case in which a cable is constructed by twisting together a plurality of insulated wires, the insulated wires of the present invention may be wired individually. Also, although the above embodiment describes a case in which the initial moisture content of the insulators 13 and 32 is 0.1 wt% or more and 0.4 wt% or less, the insulated wires 1A, 1B, 1C, 3A, 3B, 3C, and 3D may be manufactured so that the initial moisture content of the insulators 13 and 32 is 0.1 wt% or more and 0.3 wt% or less. In this case, the values ​​of E2 / E1 and E3 / E1 can be made larger, and the stability of the characteristics of the insulators 13 and 32 can be further enhanced. [Explanation of Symbols]

[0065] 1...Cable 102...Sheath 11...Conductor 111...Copper wire 12...Separator layer 120...Separator tape 13...Insulator 1A, 1B, 1C...Insulated wire 3...Cable 30...Cable 301...Sheath 31...Conductor 310...Copper wire 32...Insulator 33...Conductor 330...Copper strand 3A,3B…Insulated wire 3C,3D…Insulated wire 4,5,7,8…Equipment 61,911,921…Terminal

Claims

1. The device comprises a conductor and a fluororubber insulator that directly or indirectly covers the conductor. The water content of the insulator is 0.4 wt% or less. Insulated wire.

2. The moisture content of the insulator after being left for 24 hours in an environment with 50% humidity at room temperature following a heat aging test at 250°C for 96 hours is 0.2 wt% or more and 0.5 wt% or less. The insulated wire according to claim 1.

3. The initial elongation of the insulator is E １ The elongation of the insulator after a heating aging test in which it is held at 250°C for 96 to 672 hours, followed by being left at room temperature in an environment with 50% humidity for 24 hours, is E. ２ In that case, E ２ / E １ The value is 0.65 or higher. The insulated wire according to claim 1 or 2.

4. The initial elongation of the insulator is E １ The elongation of the insulator after a heating aging test in which it was held at 250°C for 96 hours and then left at room temperature in an environment with 50% humidity for 24 hours is E. ３ In that case, E ３ / E １ The value is 0.80 or higher. The insulated wire according to claim 1 or 2.

5. The conductor is a stranded wire made by twisting together multiple tin-plated or silver-plated copper wires. The insulated wire according to claim 1.

6. The conductor is a compressed stranded wire made by twisting together and compressing multiple copper strands. An insulated wire according to claim 1 or 5.

7. A separator layer, formed by a separator tape made of fluororesin, is provided between the conductor and the insulator. An insulated wire according to claim 1 or 5.

8. A cable in which multiple insulated wires are covered together with a sheath, The insulated wire comprises a conductor and a fluororubber insulator that directly or indirectly covers the conductor. The water content of the insulator is 0.4 wt% or less. cable.

9. A method for manufacturing an insulated electric wire comprising a conductor and a fluororubber insulator that directly or indirectly covers the conductor, An insulating material forming step, in which the insulating material is formed by extruding a rubber material around the conductor and crosslinking it, A drying step in which the insulator formed in the insulator forming step is dried to reduce the water content of the insulator to 0.4 wt% or less, A method for manufacturing an insulated electric wire equipped with [a specific feature / feature].

10. A connection structure for connecting a pair of devices using an insulated wire as described in claim 1, At least one of the pair of devices is used in a high-temperature environment. A terminal is fitted to the conductor at the end of the insulated wire. The terminal is connected to at least one of the devices. Connection structure.

11. A connection structure for connecting a pair of devices using an insulated wire as described in claim 1, The insulated wire is laid in an environment where it is immersed in high temperature, high radiation, high-temperature steam, or cutting oil. A terminal is fitted to the conductor at the end of the insulated wire. The terminal is connected to either of the pair of devices. Connection structure.

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