Expandable cable

Abstract

To provide a stretchable cable that is lightweight and highly flexible, while also exhibiting high resilience after being stretched by tensile force. [Solution] The expandable cable 1 comprises a hollow cylindrical tubular body 2 that is expandable, and a braided body 3 in which a plurality of conductor wires 31 are braided together. When a tensile force is applied, the braided body 3 stretches together with the tubular body 2, and when the tensile force is released, the braided body 3 contracts together with the tubular body 2 due to the restoring force of the tubular body 2. A portion of each of the plurality of conductor wires 31 is held in a groove 20 formed in the tubular body 2 in the longitudinal direction.

Description

Technical Field

[0001] The present invention relates to a telescopic cable having telescopic properties in the longitudinal direction.

Background Art

[0002] Conventionally, telescopic cables that expand and contract in the longitudinal direction have been used, for example, in wearable electronic devices and movable parts of robots. Patent Document 1 describes telescopic electric wires of a first aspect and a second aspect. The telescopic electric wire of the first aspect includes a cylindrical core portion configured with elastic long fibers, a conductor wire wound or braided around the outer periphery of the core portion, and an outer peripheral covering portion covering the outer peripheries of the core portion and the conductor portion. The elastic long fibers constituting the core portion have elasticity and impart elasticity to the telescopic electric wire. The outer peripheral covering portion is cylindrical and protects the internal conductor wire without inhibiting elasticity. The telescopic electric wire of the second aspect has a hollow structure without a core portion at the center, and includes a braided body in which an S-wound spiral conductor wire and a Z-wound spiral elastic long fiber are intertwined, and the outside of the braided body is covered with an outer peripheral covering portion. The Z-wound spiral elastic long fibers impart elasticity to the telescopic electric wire.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The first embodiment of the expandable wire described above has a solid structure with a core located in the center, and therefore is heavier and more rigid than the second embodiment of the expandable wire, as it is less likely to be crushed in the diametrical direction. For this reason, if the expandable wire is used in wearable electronic devices, for example, it may increase the burden on the user. On the other hand, although the expandable wire of the second embodiment is given expandability by elastic long fibers in a Z-winding spiral, the restoring force after stretching is not always sufficient, and there is a risk of loosening or sagging after stretching.

[0005] Therefore, the present invention aims to provide a stretchable cable that is lightweight and highly flexible, while also exhibiting high resilience after being stretched by tensile force. [Means for solving the problem]

[0006] The present invention aims to solve the above problems and provides an expandable cable comprising a hollow cylindrical tubular body that is expandable and a braided body in which a plurality of conductor wires are braided together, wherein when a tensile force is applied, the braided body expands integrally with the tubular body, and when the tensile force is released, the braided body contracts together with the tubular body due to the restoring force of the tubular body. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a stretchable cable that is lightweight and highly flexible, while also exhibiting high resilience after being stretched by tensile force. [Brief explanation of the drawing]

[0008] [Figure 1] (a) and (b) are external views showing a stretchable cable according to the first embodiment of the present invention. [Figure 2] (a) and (b) are cross-sectional views of the stretchable cable in a section along the longitudinal direction. [Figure 3] (a) and (b) are cross-sectional views of the stretchable cable in a section perpendicular to the longitudinal direction. [Figure 4]This is a cross-sectional view showing a single conductor wire included in a stretchable cable, with a cross-section perpendicular to its longitudinal direction. [Figure 5] (a) and (b) are explanatory diagrams showing the manufacturing process of a stretchable cable using a cylindrical dummy wire. [Figure 6] This is an enlarged view showing a magnified section A of Figure 3(a). [Figure 7] (a) is a cross-sectional view showing a stretchable cable according to modification 1 of the first embodiment. (b) is an enlarged view showing part B of (a). [Figure 8] (a) and (b) are cross-sectional views showing a stretchable cable according to a modified example 2 of the first embodiment, taken in a cross-section along the longitudinal direction. [Figure 9] (a) and (b) are cross-sectional views of the stretchable cable according to the second embodiment, taken along the longitudinal direction. [Figure 10] (a) and (b) are cross-sectional views of the stretchable cable according to the second embodiment, perpendicular to the longitudinal direction. [Figure 11] This is a cross-sectional view showing a stretchable cable according to a third embodiment. [Figure 12] This is a cross-sectional view showing a stretchable cable according to the fourth embodiment. [Modes for carrying out the invention]

[0009] [First Embodiment] Figures 1(a) and 1(b) are external views showing an expandable cable 1 according to a first embodiment of the present invention. Figures 2(a) and 2(b) are cross-sectional views of the expandable cable 1 in a cross section along the longitudinal direction. Figures 3(a) and 3(b) are cross-sectional views of the expandable cable 1 in a cross section perpendicular to the longitudinal direction. Figure 4 is a cross-sectional view showing a single conductor wire 31 included in the expandable cable 1 in a cross section perpendicular to its longitudinal direction.

[0010] This expandable cable 1 can be used, for example, in devices that incorporate electronic equipment into eyeglasses, wristbands, clothing, etc., as well as in wearable electronic devices worn by people, such as earphones and microphones, in the bending or twisting parts of robots, or in wiring for medical devices, industrial equipment, home appliances, or platform doors and elevators. More specifically as a medical device, the expandable cable 1 can be used in wristbands or clothing as wiring for monitoring heart rate, electrocardiogram, blood pressure, or blood glucose levels, for example.

[0011] The expandable cable 1 comprises a hollow cylindrical tubular body 2 that is expandable, and a braided body 3 in which multiple conductor wires 31 are braided together. When a tensile force is applied to the expandable cable 1, the braided body 3 stretches together with the tubular body 2, and when the tensile force is released, the braided body 3 contracts together with the tubular body 2 due to the restoring force of the tubular body 2. In this embodiment, the braided body 3 is made up of 16 conductor wires 31 braided together.

[0012] As shown in Figures 1(a) and (b), multiple conductor wires 31 extend from the tubular body 2 at both ends of the expandable cable 1. The multiple conductor wires 31 extending from the tubular body 2 are subjected to predetermined terminal processing for connection to the object to be connected. Connectors may also be provided at both ends of the expandable cable 1.

[0013] Figures 1(a), 2(a), and 3(a) show the stretchable cable 1 in its natural state without any tensile force applied. Figures 1(b), 2(b), and 3(b) show the stretchable cable 1 in its longitudinal state with tensile force applied. In Figures 1(b), 2(b), and 3(b), as an example, the tubular body 2 is shown stretched from its natural length L0 (see Figure 1(a)) to 1.5 times that length L1 (see Figure 1(b)).

[0014] The telescopic cable 1 has a hollow structure with a cavity 10 formed in the center, and has flexibility to easily collapse when receiving a pressing force from a direction perpendicular to the longitudinal direction. The elongation rate of the telescopic cable 1 in the longitudinal direction when a tensile force is applied is 10% or more and 300% or less. Here, the elongation rate of the telescopic cable 1 means the ratio obtained by dividing the length of the elongation of the tubular body 2 when the telescopic cable 1 is stretched to the maximum length where a plurality of conductor wires 31 are linear along the longitudinal direction of the telescopic cable 1 by the length of the tubular body 2 in the natural state. For example, if the elongation rate of the telescopic cable 1 is 300%, the length of the tubular body 2 can extend up to a maximum of 4 times the length in the natural state.

[0015] In the present embodiment, as shown in FIG. 4, the conductor wire 31 is an insulated wire, and has a conductor 311 formed by twisting a plurality of metal strands 311a, and an insulator 312 covering the conductor 311. In the example shown in FIG. 4, 7 metal strands 311a are twisted to form the conductor 311, but the number of twists is not limited to 7, and may be, for example, 3 or 19. Further, the conductor 311 is not limited to a stranded wire and may be a single wire.

[0016] As the insulator 312, for example, those made of ethylene propylene rubber, ethylene-1-octene copolymer elastomer (EOR), ethylene-1-butene copolymer elastomer (EBR), styrene-based elastomer, natural rubber, chloroprene rubber, butyl rubber, urethane rubber, silicone rubber, fluorine rubber, etc. can be used. The outer diameter (the diameter of the conductor wire 31) of the insulator 312 is, for example, 0.09 mm.

[0017] The braided body 3 is formed by spirally winding and braiding some of the multiple conductor wires 31 with other conductor wires 31 so that they intersect with each other. More specifically, of the 16 conductor wires 31, 8 conductor wires 31 are S-wound and the other 8 conductor wires 31 are Z-wound, and the 8 S-wound conductor wires 31 and the 8 Z-wound conductor wires 31 are braided together in a grid pattern. Here, S-wound refers to a winding method in which, when the expandable cable 1 is viewed from a direction perpendicular to the longitudinal direction, the conductor wires 31 extend from the upper left to the lower right, and Z-wound refers to a winding method in which, when the expandable cable 1 is viewed from a direction perpendicular to the longitudinal direction, the conductor wires 31 extend from the upper right to the lower left.

[0018] The tubular body 2 is made of a thermoplastic rubber material containing rubber components and covers the entire circumference of the braided body 3. The outer diameter of the tubular body 2 in its natural state is, for example, 3.5 mm. The elongation rate of the tubular body 2 alone is greater than or equal to the elongation rate of the stretchable cable 1, for example, between 300% and 500%. Here, the elongation rate of the tubular body 2 alone refers to the ratio obtained by dividing the length of the elongation of the tubular body 2 when it is stretched to its limit without causing damage such as breakage or cracking by the length of the tubular body 2 in its natural state. Furthermore, it is desirable that the tubular body 2 can be stretched with a relatively small tensile force, and that the stress at 100% stretch (when stretched to twice its natural length) is 3 MPa or less.

[0019] Suitable materials for the tubular body 2 include ethylene-propylene copolymer rubber (EP rubber), ethylene-1-octene copolymer elastomer (EOR), ethylene-1-butene copolymer elastomer (EBR), natural rubber, chloroprene rubber, butyl rubber, urethane rubber, silicone rubber, or fluororubber, etc., in a proportion of 50 wt% to 100 wt% of the total polymer. Plasticizers, antioxidants, flame retardants, colorants, inorganic fillers, processing aids, etc., may also be added to the tubular body 2. It is desirable that the rubber component of the tubular body 2 is crosslinked, and materials that have been crosslinked by electron beam irradiation, chemical crosslinking agents, silane coupling agents, etc., are particularly suitable.

[0020] Figures 5(a) and (b) are explanatory diagrams showing the manufacturing process of a stretchable cable 1 using a cylindrical dummy wire 4. Figure 5(a) shows a side view of the dummy wire 4, and Figure 5(b) shows a cross-section perpendicular to the longitudinal direction of the dummy wire 4. In this manufacturing method, a braided body 3 is formed by braiding multiple conductor wires 31 in a grid pattern around the dummy wire 4, and a tubular body 2 is formed by extrusion molding, where heated rubber material is extruded onto the outer circumference of the formed braided body 3. Then, after the rubber material cools and solidifies, the dummy wire 4 is removed to obtain the stretchable cable 1. Figure 5 shows the state in which the braided body 3 is formed around the dummy wire 4.

[0021] Figure 6 is an enlarged view showing section A of Figure 3(a). As shown in Figure 6, multiple grooves 20 are formed on the inner circumferential surface 2a of the tubular body 2, each holding a plurality of conductor wires 31, and a portion of the rubber material of the tubular body 2 is embedded between the plurality of conductor wires 31. These grooves 20 are imprints created when the rubber material is pushed aside by the conductor wires 31 during the extrusion molding of the tubular body 2. A portion of each of the plurality of conductor wires 31 is held in the groove 20 in the longitudinal direction and is integrated with the tubular body 2. In addition, the insulator 312 of the conductor wires 31 may melt and fuse with the tubular body 2 due to the heat during the extrusion molding of the tubular body 2. In this case, the plurality of conductor wires 31 are more firmly integrated with the tubular body 2.

[0022] Because multiple conductor wires 31 are held in the grooves 20 of the tubular body 2, when a tensile force is applied to the expandable cable 1, the braided body 3 stretches together with the tubular body 2. When the tensile force is released, the braided body 3 contracts together with the tubular body 2 due to the restoring force of the tubular body 2. As a result, for example, when the expandable cable 1 is wired to a movable part such as a wearable electronic device or a robot joint, the expandable cable 1 will stretch flexibly in accordance with the movement of the movable part, eliminating the need to wire it with excess length. Consequently, even when the wiring space for the expandable cable 1 is narrow, the expandable cable 1 is less likely to interfere with surrounding materials, and damage to the expandable cable 1 due to such interference and the occurrence of kinks can be suppressed.

[0023] In other words, by using the expandable cable 1 as wiring material for movable parts, the durability against bending and twisting movements of the movable parts (i.e., resistance to bending and twisting) can be improved. Furthermore, since the expandable cable 1 has multiple conductor wires 31 arranged spirally, which are more rigid than the tubular body 2, the rigidity of the multiple conductor wires 31 maintains the overall shape of the expandable cable 1, making it less prone to buckling.

[0024] The elongation rate of the expandable cable 1 can be adjusted by the material and diameter used for the tubular body 2, the spiral pitch when arranging the multiple conductor wires 31 spirally, and the number of conductor wires 31 included in the braided body 3. Here, the spiral pitch of the conductor wires 31 is the distance along the longitudinal direction of the expandable cable 1 at points on the conductor wires 31 that are at the same circumferential position when the conductor wires 31 are arranged spirally.

[0025] (Effects of the first embodiment) According to the first embodiment of the present invention described above, when the tensile force is released, the braided body 3 contracts due to the restoring force of the tubular body 2, thus providing high resilience after being stretched by tensile force. Furthermore, since the expandable cable 1 has a hollow structure with a cavity 10 formed in the center, it is lightweight and highly flexible. In addition, in the first embodiment, the outer circumference of the braided body 3 is covered by the tubular body 2, so the conductor wire 31 can be protected by the tubular body 2.

[0026] [Modification 1 of the first embodiment] Figure 7(a) is a cross-sectional view of the expandable cable 1A according to Modification 1 of the first embodiment, taken perpendicular to the longitudinal direction. Figure 7(b) is an enlarged view showing part B of Figure 7(a). In this Modification 1, the rubber material of the tubular body 2A protrudes more significantly toward the inner circumference between the multiple conductor wires 31 than in the first embodiment, and the multiple conductor wires 31 are embedded more deeply in the tubular body 2A. A part of the tubular body 2A is a protruding portion 21 that protrudes from between the multiple conductor wires 31 toward the center line C of the tubular body 2A. As shown in Figure 7(a), the minimum distance D1 between the protruding portion 21 and the center line C is shorter than the distance D2 between the center position of the conductor wire 31 in the portion embedded in the tubular body 2A and the center line C. Such a shape of the tubular body 2A can be achieved, for example, by increasing the extrusion pressure when extruding the rubber material of the tubular body 2A. According to this Modification 1, it is possible to improve the integration between the multiple conductor wires 31 and the tubular body 2A.

[0027] [Modification 2 of the first embodiment] Figures 8(a) and 8(b) are cross-sectional views of the stretchable cable 1B according to Modification 2 of the First Embodiment, taken in a cross-sectional view along its longitudinal direction. Figure 8(a) shows the stretchable cable 1B in its natural state without tensile force applied, and Figure 8(b) shows the stretchable cable 1B with tensile force applied. In the First Embodiment, as shown in Figures 2(a) and 2(b), when the braided body 3 is viewed in the circumferential direction, S-wound conductor wires 31 and Z-wound conductor wires 31 appear alternately, one at a time. However, in the stretchable cable 1B according to Modification 2, two S-wound conductor wires 31 and two Z-wound conductor wires 31 appear alternately. The intersections of the S-wound conductor wires 31 and the Z-wound conductor wires 31 are aligned in the longitudinal direction of the stretchable cable 1B, similar to the stretchable cable 1 according to the First Embodiment. This Modification 2 also provides the same functions and effects as the First Embodiment.

[0028] [Second Embodiment] A second embodiment of the present invention will be described with reference to Figures 9(a) and (b) and Figures 10(a) and (b). Figures 9(a) and (b) are cross-sectional views of the expandable cable 1C according to the second embodiment, along the longitudinal direction. Figures 10(a) and (b) are cross-sectional views of the expandable cable 1C in a cross-section perpendicular to the longitudinal direction. Figures 9(a) and 10(a) show the expandable cable 1B in its natural state, without any tensile force applied. Figures 9(b) and 10(b) show the expandable cable 1C in a state where tensile force is applied and it is stretched in the longitudinal direction.

[0029] In the first embodiment, a case was described in which a braided body 3 is constructed by braiding multiple conductor wires 31. In this embodiment, however, a braided body 3C is constructed by braiding multiple conductor wires 31 together with stretchable wires 32, which have higher elasticity and adhesion to the tubular body 2 than the multiple conductor wires 31. More specifically, the braided body 3C is constructed by braiding 12 conductor wires 31 and 4 stretchable wires 32 in a grid pattern. Of the 4 stretchable wires 32, two are S-wound and the other two are Z-wound. That is, in this embodiment, 6 conductor wires 31 and 2 stretchable wires 32 are S-wound, and 6 conductor wires 31 and 2 stretchable wires 32 are Z-wound. Note that in Figures 8(a) and (b), a cross-section along the longitudinal direction is shown, so the apparent directions of S-winding and Z-winding are reversed.

[0030] The expandable wire 32 fuses with the tubular body 2C at multiple points along its longitudinal direction due to the heat generated during the extrusion molding of the tubular body 2C, becoming an integral part of the tubular body 2C. The material of the tubular body 2C is preferably the same as the material of the tubular body 2 according to the first embodiment, and may contain ethylene-propylene copolymer rubber (EP rubber), ethylene-1-octene copolymer elastomer (EOR), ethylene-1-butene copolymer elastomer (EBR), natural rubber, chloroprene rubber, butyl rubber, urethane rubber, silicone rubber, or fluororubber, etc., in a proportion of 50 wt% to 100 wt% of the total polymer. The material of the expandable wire 32 is preferably one that easily integrates with the tubular body 2C, and is preferably a material of the same type as the tubular body 2C.

[0031] According to this second embodiment, the multiple conductor wires 31 are pressed against the tubular body 2 by the multiple stretchable wires 32, preventing the conductor wires 31 from detaching from the groove 20. Furthermore, since the stretchable wires 32 are elastic, the expandable cable 1C can be stretched and contracted more flexibly in the longitudinal direction. In addition, as the material for the insulator 312 of the conductor wires 31, a material with excellent electrical properties as an insulator can be selected without prioritizing adhesion to the tubular body 2C. If a material that is easily separable from the tubular body 2C is used as the material for the insulator 312, terminal processing at both ends of the expandable cable 1C becomes easier. Specifically, fluororesins (PTFE, PFA, ETFE, FEP), cross-linked resins, or rubber can be used as the material for the insulator 312. Note that, as in the modified example 2 of the first embodiment, multiple conductor wires 31 and stretchable wires 32 may be combined in pairs and braided together.

[0032] [Third Embodiment] A third embodiment of the present invention will be described with reference to Figure 11. Figure 11 is a cross-sectional view showing an expandable cable 1D according to the third embodiment. In the first embodiment, a case was described in which a tubular body 2 covers the outer circumference of a braided body 3 and conductor wires 31 are held in grooves 20 formed on the inner circumferential surface 2a of the tubular body 2. In the expandable cable 1D according to the third embodiment, the inner circumference of a braided body 3D, which is made up of a plurality of conductor wires 31, is covered by an expandable hollow cylindrical tubular body 2D, and conductor wires 31 are held in grooves 20D formed on the outer circumferential surface 2b of the tubular body 2D. This third embodiment also provides an expandable cable 1D that is lightweight and highly flexible, and has high resilience after being stretched by tensile force, similar to the first embodiment. Note that some of the plurality of conductor wires 31 may be replaced with expandable wires 32 according to the second embodiment.

[0033] [Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to Figure 12. Figure 12 is a cross-sectional view showing an expandable cable 1E according to the fourth embodiment. In the expandable cable 1E according to the fourth embodiment, a braided body 3E, which is made by braiding a plurality of conductor wires 31, is covered by a hollow cylindrical tubular body 2E whose inner and outer circumferences are both expandable, and the plurality of conductor wires 31 are embedded in the tubular body 2E. In Figure 12, the braided body 3E embedded in the tubular body 2E is shown by a dashed line. This fourth embodiment also provides an expandable cable 1E that is lightweight and highly flexible, and has high resilience after being stretched by tensile force, similar to the first embodiment. Furthermore, since the plurality of conductor wires 31 are embedded in the tubular body 2E, it is possible to prevent the conductor wires 31 from detaching from the tubular body 2E. Note that some of the plurality of conductor wires 31 may be replaced with the expandable wire 32 according to the second embodiment.

[0034] (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.

[0035] [1] A stretchable cable (1,1A,1B,1C,1D,1E) comprising a stretchable hollow cylindrical tubular body (2,2A,2B,2C,2D,2E) and a braided body (3,3A,3B,3C,3D,3E) made by braiding a plurality of conductor wires (31), wherein when a tensile force is applied, the braided body (3,3A,3B,3C,3D,3E) stretches together with the tubular body (2,2A,2B,2C,2D,2E), and when the tensile force is released, the braided body (3,3A,3B,3C,3D) contracts together with the tubular body (2,2A,2B,2C,2D,2E) due to the restoring force of the tubular body (2,2A,2B,2C,2D,2E).

[0036] [2] The expandable cable (1, 1A, 1B, 1C, 1D) described in [1] above, wherein each of the plurality of conductor wires (31) is held in a groove (20, 20D) formed in the tubular body (2, 2A, 2B, 2C, 2D) in the longitudinal direction.

[0037] [3] The stretchable cable (1, 1A, 1B, 1C) as described in [1] above, wherein the groove (20) is formed on the inner surface (2a) of the tubular body, and the outer circumference of the braided body (3, 3A, 3B, 3C) is covered by the tubular body (2, 2A, 2B, 2C).

[0038] [4] The stretchable cable (1, 1A, 1B, 1C, 1D, 1E) described in [1] above, wherein the braided body (3, 3A, 3B, 3C, 3D, 3E) is braided by spirally winding some of the multiple conductor wires (31) and some of the other conductor wires (31) intersect with each other.

[0039] [5] The stretchable cable (1C) described in [1] above, wherein the braided body (3B) is braided together with the plurality of conductor wires (31) by stretchable wires (32) which have higher elasticity and adhesion to the tubular body (2C) than the plurality of conductor wires (31).

[0040] [6] The expandable cable (1, 1A, 1B, 1C, 1D, 1E) described in [1] above, wherein the tubular body (2, 2A, 2B, 2C, 2D, 2E) is made of rubber material, and a portion of the rubber material is inserted between the plurality of conductor wires (31).

[0041] [7] A stretchable cable (1, 1A, 1B, 1C, 1D, 1E) according to any of [1] to [6] above, wherein the longitudinal elongation rate when the tensile force is applied is 10% or more and 300% or less.

[0042] [8] The tubular body (2, 2A, 2B, 2C, 2D, 2E) is the stretchable cable (1, 1A, 1B, 1C, 1D, 1E) described in [7] above, wherein the stress when fully extended is 3 MPa or less.

[0043] Although the first to fourth embodiments and modifications of the present invention have been described above, these embodiments and modifications do not limit the invention as defined in the claims. It should also be noted that not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention. Furthermore, the present invention can be modified and implemented without departing from its spirit, and for example, the following modifications are possible.

[0044] In the first to fourth embodiments and modifications described above, the case where the conductor wire 31 is an insulated wire has been explained, but the invention is not limited to this, and the conductor wire 31 may be only an uninsulated metal conductor. Also, in the first to third embodiments and modifications, the case in which 16 conductor wires 31 or 12 conductor wires 31 and 4 expandable wires 32 are braided together to form braided bodies 3, 3A, 3B, 3C, 3D, and 3E has been explained, but the number of conductor wires 31 and expandable wires 32 is not limited to these, and for example, two conductor wires 31 may be wound in an S-winding and a Z-winding to form a braided body. [Explanation of Symbols]

[0045] 1, 1A, 1B, 1C, 1D, 1E… Stretchable Cable 2,2B,2C,2C,2D,2E…tubular body 2a…Inner peripheral surface 2b…Outer surface 20,20D…Groove 3,3A,3B,3C,3D,3E…braided body 31... Conductor wire 32...Stretch line

Claims

1. A hollow cylindrical tubular body that is expandable, It comprises a braided body in which multiple conductor wires are braided together, The aforementioned plurality of conductor wires are insulated wires having a conductor formed by twisting together a plurality of metal strands and an insulator covering the conductor. When a tensile force is applied, the braided body stretches integrally with the tubular body, and when the tensile force is released, the braided body contracts together with the tubular body due to the restoring force of the tubular body. Expandable cable.

2. The insulator and the tubular body are integrated by fusion. The expandable cable according to claim 1.

3. Each of the aforementioned plurality of conductor wires is held in a groove formed in the tubular body, with a portion of its longitudinal direction being retained. The expandable cable according to claim 1.

4. The groove is formed on the inner surface of the tubular body, and the outer circumference of the braided body is covered by the tubular body. The expandable cable according to claim 3.

5. The braided body is formed by spirally winding and braiding some of the multiple conductor wires so that some of the conductor wires and some of the conductor wires intersect with each other. The expandable cable according to claim 1.

6. The braided body is formed by braiding together the multiple conductor wires with stretchable wires that have higher elasticity and adhesion to the tubular body than the multiple conductor wires. The expandable cable according to claim 1.

7. The material of the aforementioned expansion joint is the same type of material as the aforementioned tubular body. The expandable cable according to claim 6.

8. The material of the aforementioned insulator is a fluororesin. The expandable cable according to claim 6.

9. The tubular body is made of rubber material, A portion of the rubber material is inserted between the plurality of conductor wires. The expandable cable according to claim 1.

10. The longitudinal elongation rate when the aforementioned tensile force is applied is 10% or more and 300% or less. The stretchable cable according to any one of claims 1 to 9.

11. The tubular body has a stress of 3 MPa or less when fully extended. The expandable cable according to claim 10.

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