Multicore cable

Abstract

To provide a multicore cable having a simple structure and high durability.SOLUTION: A multicore cable has a plurality of cable units, a shield layer covering the plurality of cable units, and a jacket, in which the plurality of cable units are bundled, where an outer diameter of the jacket is 10 mm or less. The cable unit has a plurality of core electric wires, and a coaxial electric wire is included in the core electric wire. The coaxial electric wire has a central conductor, an insulation layer covering the central conductor, an outer conductor covering the insulation layer, and a jacket covering the outer conductor, in which a diameter of the central conductor is 0.09 mm or less. The shield layer is constituted of a metal braid in which metal wires are braided, in which a braid angle of the metal braid is 60 degrees or more and 64 degrees or less.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to multi-conductor cables. [Background technology]

[0002] Patent Document 1 discloses a mobility cable having a shielding layer with a braided structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-326525 Summary of the Invention [Problem to be solved by the invention]

[0004] Multi-core cables are often used in environments where they are required to bend and twist multiple times. However, improving the bending and twisting properties of conventional multi-core cables required a complex structure and the use of expensive materials.

[0005] An object of the present disclosure is to provide a multi-core cable that has a simple structure and is highly durable. [Means for solving the problem]

[0006] A multi-core cable according to one embodiment of the present disclosure includes: The cable connector includes a plurality of cable units, a shield layer that covers the plurality of cable units, and an outer jacket, A multi-core cable in which a plurality of the cable units are bundled together, The outer diameter of the outer jacket is 10 mm or less, The cable unit has a plurality of core wires, The core wire includes a coaxial wire, The coaxial wire includes a central conductor, an insulating layer covering the central conductor, an outer conductor covering the insulating layer, and an outer jacket covering the outer conductor, The diameter of the central conductor is 0.09 mm or less, The shield layer is made of a metal braid in which metal wires are braided, The braid angle of the metal braid is equal to or greater than 60 degrees and equal to or less than 64 degrees. Effect of the Invention

[0007] According to the above, it is possible to improve the durability of the multi-core cable with a simple structure. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a connectorized cable according to the present disclosure. [Diagram 2] FIG. 2 is an enlarged view of the end of the cable shown in FIG. [Diagram 3] FIG. 3 is a side view showing the metal braid of the cable shown in FIG. [Figure 4A] FIG. 4A is a side view showing the metal braid of a cable according to the present disclosure. [Figure 4B] FIG. 4B is a side view showing the metal braid of the cable according to the comparative example. [Diagram 5] FIG. 5 is a schematic diagram showing a bending test performed on a cable according to the present disclosure. [Figure 6] FIG. 6 is a schematic diagram showing a twist test performed on a cable according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described. A multi-core cable according to one embodiment of the present disclosure includes: (1) A multicore cable having a plurality of cable units, a shielding layer covering the plurality of cable units, and an outer sheath, in which the plurality of cable units are bundled together, wherein the outer diameter of the outer sheath is 10 mm or less, the cable units have a plurality of core wires, the core wires include a coaxial wire, the coaxial wire has a central conductor, an insulating layer covering the central conductor, an outer conductor covering the insulating layer, and an outer sheath covering the outer conductor, the diameter of the central conductor is 0.09 mm or less, the shielding layer is composed of a metal braid made of braided metal wires, and the braid angle of the metal braid is 60 degrees or more and 64 degrees or less.

[0010] According to this configuration, the durability of the multi-core cable can be easily improved by adjusting the braid angle of the metal braid (shielding layer) that covers the cable unit.

[0011] (2) In the above (1), the braid density of the metal braid may be 97% or more.

[0012] According to this configuration, the durability of the multi-core cable can be easily improved by adjusting the braid density of the metal braid (shield layer) covering the cable unit.

[0013] [Details of the embodiment of the present disclosure] Specific examples of multi-core cables according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0014] In addition, U, D, F, B, R, and L shown in Figure 1 etc. indicate directions in the multi-core cable 1, where U is up, D is down, F is front, B is rear, R is right, and L is left.

[0015] A multi-core cable 1 according to the present disclosure will be described with reference to Figs. 1 and 2. Fig. 1 is a schematic cross-sectional view showing an example of the multi-core cable 1 according to the present disclosure. Fig. 2 is an enlarged view of an end of the multi-core cable 1 according to the present disclosure. The multi-core cable 1 according to this embodiment can be used, for example, for wiring in medical electronic devices. As shown in Fig. 1, the multi-core cable 1 has a plurality of cable units 3, a tape layer 4 bundling the plurality of cable units 3, a shield layer 5 covering the tape layer 4, and an outer sheath 6 covering the shield layer 5. Each of the plurality of cable units 3 has a plurality of electric wires 2.

[0016] In the electric wire according to the present disclosure, although not shown in the drawings, the electric wire 2 has at least a central conductor. The central conductor is a single wire made of a conductive metal such as a copper alloy or a twisted wire made by twisting together a plurality of thin wires. The insulating layer is formed of an insulating resin, and protects the central conductor and electrically insulates the central conductor from the surroundings. Since the multi-core cable 1 according to the present disclosure is expected to be used in an environment where bending and twisting are performed multiple times, it is desirable that the diameter of the central conductor is 0.048 mm or more and 0.09 mm or less. In addition, at least one cable unit 3 includes a coaxial electric wire as the electric wire 2. The coaxial electric wire has a central conductor, an insulating layer covering the central conductor, an outer conductor covering the insulating layer, and an outer sheath covering the outer conductor.

[0017] The cable unit 3 according to the present disclosure is configured by bundling a plurality of electric wires 2. The electric wires 2 may be bundled with, for example, tape or may be hardened with resin or the like. In the multi-core cable 1 according to the present embodiment, one cable unit 3 has 16 electric wires 2.

[0018] As shown in FIG. 1, in the multi-core cable 1 according to the present disclosure, a plurality of cable units 3 are bundled by a tape layer 4. The tape layer 4 is made of, for example, polyethylene terephthalate. From the viewpoint of the flexibility of the multi-core cable 1, the thickness of the tape layer is preferably 5 μm or more and 30 μm or less. In the multi-core cable according to the present embodiment, the cable units 3 are bundled by the tape layer 4, so that gaps are generated between the plurality of cable units 3. Note that the tape layer 4 is not essential, and can be substituted by, for example, winding a filament of resin or the like other than tape. The multi-core cable 1 according to the present embodiment is configured by bundling ten cable units 3 by the tape layer 4.

[0019] The tape layer 4 is further covered with a shielding layer 5. In the present disclosure, the shielding layer 5 is made of a metal braid as shown in FIG. 2, and suppresses noise leakage and suppresses noise from being carried on the signal propagating through the central conductor. In addition, by making the shielding layer 5 of a metal braid, the flexibility of the multi-core cable 1 can be improved. In this embodiment, the metal braid of the shielding layer 5 is made of unplated tin-copper alloy wire (tin content 0.3 mass%), and the diameter of the wire used for the metal braid is 0.04 mm or more and 0.10 mm or less. From the viewpoint of flexibility, the inner diameter of the shielding layer 5 is preferably 7.2 mm or more and 7.8 mm or less. The metal braid of the shielding layer 5 is made by weaving together a first braid 5a extending in a direction intersecting the axial direction of the multi-core cable 1 and a second braid 5b extending in a direction intersecting the axial direction of the multi-core cable 1 and the direction in which the first braid 5a extends. The braid density of the metal braid is 97% or more from the viewpoint of blocking external noise.

[0020] The shielding layer 5 is further covered with an outer jacket 6. The outer jacket 6 is formed of an insulating resin, and electrically insulates the shielding layer 5 from the outside and prevents damage to the shielding layer 5. The outer jacket 6 is made of polyvinyl chloride (PVC), thermoplastic elastomer (TPE), particularly polyolefin thermoplastic elastomer (TPO), or the like. In view of the environment in which the multi-core cable 1 according to the present disclosure is used, the outer diameter of the outer jacket 6 is 10 mm or less.

[0021] Next, the shield layer 5 of the multi-core cable 1 according to the present disclosure will be described in detail with reference to FIG. 3. FIG. 3 is a side view showing a schematic view of the metal braid of the cable shown in FIG. 2. In FIG. 3, the F direction and the B direction are the axial direction of the multi-core cable 1. As shown in FIG. 3, the metal braid is woven so that the first braid 5a and the second braid 5b cross at a certain angle. In FIG. 3, the angle α at which the first braid 5a or the second braid 5b crosses with respect to the imaginary line H perpendicular to the cable axial direction is called the braid angle α. In the multi-core cable 1 according to the present disclosure, the braid angle α is 60 degrees or more and 64 degrees or less. By setting the braid angle α to 60 degrees or more and 64 degrees or less, the durability of the multi-core cable 1 can be improved.

[0022] Next, the relationship between the braid angle α and the durability of the multi-core cable 1 will be described in detail with reference to Figures 4A and 4B. Figure 4A is a side view showing the metal braid of the multi-core cable according to the present disclosure. Figure 4B is a side view showing the metal braid of the multi-core cable 1 according to a comparative example. Also, arrows showing how the force is applied when a bending force F is applied to each multi-core cable in the axial direction of the multi-core cable 1 are shown in Figures 4A and 4B, respectively.

[0023] The braid angle α of the multi-core cable 1 according to the present disclosure (FIG. 4A) is 60 degrees or more and 64 degrees or less. On the other hand, the braid angle α of the multi-core cable 1 according to the comparative example (FIG. 4B) is greater than 64 degrees. As shown in FIG. 4A, the multi-core cable 1 according to the present disclosure has a smaller braid angle α than the comparative example. Therefore, when the multi-core cable 1 is bent and a bending force F is applied along the elongation direction of the outer or inner part of the bend, the bending force FA1 in the direction parallel to the metal braid is smaller than the bending force FA2 in the comparative example. In other words, the multi-core cable 1 according to the present disclosure can suppress the strain on the metal braid (the elongation strain in the length direction of the wires of the metal braid). If the braid angle α is set to be smaller than 60 degrees, the number of times the metal braid is wound increases significantly, which significantly increases the time required to manufacture the multi-core cable, and the thickness of the shield layer 5 increases, which increases the diameter of the multi-core cable 1.

[0024] In order to measure the durability of the multi-core cable 1 according to the present disclosure, two types of multi-core cables, Example 1 and Comparative Example 1, were fabricated and subjected to bending tests and twisting tests. The multi-core cable of Example 1 had a braid angle α of 62 degrees, and the multi-core cable of Comparative Example 1 had a braid angle α of 66 degrees. The configurations other than the braid angle α were the same. When the braid angle α was 62 degrees, the braid density was approximately 97%. The test method will be described in detail with reference to Figs. 5 and 6. Fig. 5 is a schematic diagram showing the test method for the bending test. Fig. 6 is a schematic diagram showing the test method for the twisting test.

[0025] (Bending test) As shown in FIG. 5, the bending test was performed by clamping and fixing the multi-core cable 1 between a pair of mandrels 100, and bending the multi-core cable 1 along the mandrels 100. One cycle (one time) consisted of bending the multi-core cable 1 along one mandrel 100, returning it to its original position, bending it along the other mandrel 100, and returning it to its original position. After 250,000 cycles of bending test on the multi-core cable 1, the breakage state and electrical conduction state of the multi-core cable 1 were confirmed. The bending test was performed with the bending angle of the multi-core cable 1 at ±90 degrees, the bending speed at 30 cycles / min, the bending radius (radius of the mandrel) at 30 mm, and a load 101 of 1000 g applied to the end of the multi-core cable 1.

[0026] As a result of the bending test, in the multi-core cable of Example 1, even when repeatedly bent 250,000 times, the metal braid did not break, and electrical signal conduction was confirmed. On the other hand, in the multi-core cable of Comparative Example 1, the metal braid broke after repeatedly bent 150,000 times, and electrical signal conduction was not confirmed. From the above bending test results, it was confirmed that the durability of the multi-core cable 1 against bending can be improved by setting the braid angle α to be 60 degrees or more and 64 degrees or less.

[0027] (Twisting test) As shown in FIG. 6, the twisting test was performed by fixing one end of the multi-core cable 1 by the fixed end 200, fixing the end opposite to the end fixed by the fixed end 200 by the rotating end 201, and twisting the multi-core cable 1 by rotating the rotating end 201. The rotating end 201 was rotated 180 degrees clockwise from the initial position when the multi-core cable 1 was viewed from the U direction, then returned to the initial position, rotated 180 degrees counterclockwise, and returned to the original position, which was defined as one cycle (one time). After 250,000 cycles of twisting test on the multi-core cable 1, the break state of the multi-core cable 1 and the electrical conduction state of the shield layer 5 were confirmed. The twisting test was performed with the distance D from the fixed end 200 to the rotating end 201 being 500 mm, and the rotation speed of the rotating end 201 being 30 cycles / min. The weight of the rotating end 201 was 1000 g, and the test was performed with a load of 1000 g constantly applied to the multi-core cable 1.

[0028] As a result of the twisting test, in the multi-core cable of Example 1, even after 250,000 repeated twists, the metal braid did not break, and electrical signal continuity was confirmed. On the other hand, in the multi-core cable of Comparative Example 1, the metal braid broke after 150,000 repeated twists, and electrical signal continuity could not be confirmed. From the above twisting test results, it was confirmed that the multi-core cable 1 can achieve improved durability against twisting by setting the braid angle α to be 60 degrees or more and 64 degrees or less.

[0029] Multi-core cables are sometimes used in environments where they are required to bend and twist multiple times. In order to improve the bending and twisting properties of conventional multi-core cables, it was necessary to use complicated structures and expensive materials. Therefore, there was a need for a simple method to improve the durability of multi-core cables. The inventors have discovered that the durability of a multi-core cable can be easily improved by adjusting the braid angle of the metal braid (shielding layer) that covers the cable unit. According to the multi-core cable 1 of the present disclosure, by setting the braid angle α of the metal braid to be equal to or greater than 60 degrees and equal to or less than 64 degrees, a highly durable multi-core cable 1 can be provided with a simple structure.

[0030] Although the embodiment of the present disclosure has been described above, it goes without saying that the technical scope of the present disclosure should not be interpreted as being limited by the description of the present embodiment. The present embodiment is merely an example, and it is understood by those skilled in the art that various modifications of the embodiment are possible within the scope of the invention described in the claims. The technical scope of the present disclosure should be determined based on the scope of the invention described in the claims and its equivalents. [Explanation of symbols]

[0031] 1 Multi-core cable 2 electric wire 3 Cable Unit 4 Tape Layers 5 Shielding Layer 5a first braid 5b second braid 6 Outer cover 100 mandrels 101 Load 200 fixed end 201 Rotating end

Claims

1. The cable connector includes a plurality of cable units, a shield layer that covers the plurality of cable units, and an outer jacket, A multi-core cable in which a plurality of the cable units are bundled together, The outer diameter of the jacket is 10 mm or less, The cable unit has a plurality of core wires, The core wire includes a coaxial wire, The coaxial wire includes a central conductor, an insulating layer covering the central conductor, an outer conductor covering the insulating layer, and an outer jacket covering the outer conductor, The diameter of the central conductor is 0.09 mm or less, The shield layer is made of a metal braid in which metal wires are braided, The braid angle of the metal braid is 60 degrees or more and 64 degrees or less. Multi-core cable.

2. 2. The multi-core cable according to claim 1, wherein the braid density of the metal braid is 97% or more.

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