Cable

Abstract

To provide a stretchable cable that has a small outer diameter and is easily stretchable.SOLUTION: A cable 1 includes: a collective core 4 in which a plurality of electric wires 3 or a plurality of strands 7 made by twisting together a plurality of electric wires 3 are concentrically twisted in two layers or more around a linear central filler 2 having elasticity; and a sheath 6 that covers around the collective core 4 and has elasticity. An outer diameter of the sheath 6 is not more than 30 times an outer diameter of the electric wire 3. A thickness of the sheath 6 is 5% or more of the outer diameter of the sheath 6, and P / Pd, which is the ratio of the twist pitch P to the pitch diameter Pd is 3-5 in each layer of the collective core 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cable. [Background technology]

[0002] Medical cables used in ultrasound diagnostic equipment and other devices are expected to be used in a variety of situations. For example, there may be times when it is necessary to temporarily extend the cable to a distant location. If the cable were to be made longer to accommodate such situations, it would take up more space and be less easy to handle, so there is a demand for stretchable cables that can be extended when needed.

[0003] A known example of a conventional stretchable cable is a curl cord (see, for example, Patent Document 1). Note that Patent Document 2 is another prior art document related to the invention of this application. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2016-21312 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-198992 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned curled cord has a large outer diameter when curled, which increases the space occupied by the cable. Therefore, a cable that is easy to stretch without increasing the outer diameter is desired.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a stretchable cable that has a small outer diameter and is easily stretchable. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a cable comprising: an aggregate core formed by concentrically twisting a plurality of electric wires, or a plurality of child wires formed by twisting a plurality of the electric wires together, in two or more layers around an elastic linear central core; and an elastic sheath covering the aggregate core, wherein the outer diameter of the sheath is 30 times or less the outer diameter of the electric wires, the thickness of the sheath is 5% or less of the outer diameter of the sheath, and in each layer of the aggregate core, P / Pd, which is the ratio of layer core diameter Pd to twist pitch P, is 3 or more and 5 or less. [Effects of the Invention]

[0008] According to the present invention, a stretchable cable having a small outer diameter and being easily stretchable is provided. [Brief explanation of the drawings]

[0009] [Figure 1] 1A is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a cable according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a coaxial line. [Figure 2] 10A and 10B are diagrams illustrating expansion and contraction of a collective core. [Figure 3] 1(a) is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a cable according to another embodiment of the present invention, and FIG. 1(b) is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a child strand. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Embodiment Mode] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0011] 1(a) is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a cable 1 according to this embodiment, and (b) is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a coaxial line 30. The cable 1 is used, for example, as a probe cable connected to a probe of an ultrasound diagnostic device.

[0012] 1(a), the cable 1 includes an aggregated core 4 formed by concentrically twisting a plurality of electric wires 3 in two or more layers around a central core 2, and a sheath 6 covering the aggregated core 4. In this embodiment, the cable 1 includes a collective shield layer 5 between the aggregated core 4 and the sheath 6.

[0013] The cable 1 according to this embodiment has a small outer diameter (outer diameter of the sheath 6) of 30 times or less the outer diameter of the electric wires 3 constituting the collective core 4, yet is easily stretchable, stretching by 20% or more in the cable longitudinal direction. Furthermore, the thickness of the sheath 6 is 5% or more of the outer diameter of the cable 1 (outer diameter of the sheath 6), maintaining a small diameter while maintaining the thickness of the sheath 6. Thus, according to this embodiment, it is possible to realize a cable 1 that is easily stretchable while maintaining a small outer diameter and a thick sheath 6. Each part of the cable 1 will be described in detail below.

[0014] (center intervention 2) The central filler 2 is made of an elastic linear material that easily stretches in the longitudinal direction. The central filler 2 is located at the center of the cable where stress tends to concentrate when the cable 1 is bent, enhancing the cable 1's resistance to bending and other stresses. The central filler 2 and the sheath 6 (described later) also function to prevent the cable 1 from stretching too much when the cable 1 is stretched in the longitudinal direction, and to provide a restoring force that allows the cable 1 to return to its original length when the stretching force is released. As will be described in detail later, in this embodiment, each layer of the collective core 4 is designed to stretch by approximately 20%, so the central filler 2 should preferably be made of a material that does not undergo plastic deformation at approximately 20% elongation (i.e., returns to its original length even after approximately 20% elongation). The central filler 2 can be made of a rubber material such as silicone rubber or butyl rubber. Here, a central filler 2 with an outer diameter of 2.3 mm was used.

[0015] (Electric wire 3) In this embodiment, the electric wire 3 constituting the collective core 4 is a coaxial wire 30. The coaxial wire 30 includes a conductor 31, an insulator 32 surrounding the conductor 31, a shield layer 33 surrounding the insulator 32, and a jacket 34 surrounding the shield layer 33. The conductor 31 is a stranded conductor formed by twisting together multiple metal wires. Here, the conductor 31 used has an outer diameter of 0.075 mm and is formed by twisting together seven metal wires made of silver-plated copper alloy wires with an outer diameter of 0.025 mm. In addition, in this embodiment, the insulator 32 has a two-layer structure in which a foam layer made of foamed PFA (tetrafluoroethylene-perfluoroalkoxyethylene copolymer) is surrounded by a skin layer made of PET (polyethylene terephthalate). The foam layer has a thickness of 0.078 mm, and the skin layer has a thickness of 0.01 mm. The shield layer 33 is a horizontally wound shield formed by horizontally wound tin-plated hard copper wire with an outer diameter of 0.025 mm. The outer diameter of the shielding layer 33 was 0.30 mm. A material made of PET was used as the jacket 34. The thickness of the jacket 34 was 0.02 mm, and the outer diameter of the jacket 34, i.e., the outer diameter of the coaxial cable 30, was 0.34 mm.

[0016] The electric wires 3 constituting the collective core 4 are not limited to the coaxial wires 30, and may be, for example, insulated electric wires that do not have the shield layer 33 and the jacket 34. This embodiment is directed to small-diameter electric wires 3, and the outer diameter of the electric wires 3 should be at least 0.5 mm or less.

[0017] (Collective Core 4) The collective core 4 is formed by concentrically twisting a plurality of electric wires 3 around a central spacer 2 in two or more layers. Here, the collective core 4 was formed by concentrically twisting 198 electric wires 3 into six layers. Hereinafter, the layers constituting the collective core 4 will be referred to as the first to sixth layers from the radially inner side (the central spacer 2 side) to the radially outer side (the sheath 6 side). The number of electric wires 3 in each layer is 20 in the first layer, 25 in the second layer, 30 in the third layer, 36 in the fourth layer, 41 in the fifth layer, and 46 in the sixth layer. Note that the number of electric wires 3 constituting the collective core 4 and the number of layers are not limited to those shown in the figure. However, the number of electric wires 3 constituting the collective core 4 is preferably at least 64 or more, and more preferably 100 or more. Considering the possibility of the electric wires 3 being misaligned, the upper limit of the number of electric wires 3 constituting the collective core 4 is approximately 500. Although there are gaps between the electric wires 3 in FIG. 1(a), it is also possible to configure the electric wires 3 so that there are no gaps.

[0018] In the cable 1 according to the present embodiment, the ratio P / Pd of the layer core diameter Pd to the twist pitch P in each layer of the assembled core 4 is set to 3 or more and 5 or less. By setting the P / Pd of each layer of the assembled core 4 to 5 or less, the electric wires 3 in each layer are wound in a curled state with a very small twist pitch P, which makes the assembled core 4 more likely to stretch in the cable longitudinal direction when the cable 1 is pulled, as shown in FIG. 2 . Furthermore, by setting the P / Pd of each layer to 3 or more, breakage of the electric wires 3 when the cable 1 is twisted can be suppressed. In this resin embodiment, the P / Pd of each layer is set to approximately 4.5. More specifically, the twist pitch P of each layer is set to 12 mm for the first layer, 14 mm for the second layer, 17 mm for the third layer, 20 mm for the fourth layer, 23 mm for the fifth layer, and 26 mm for the sixth layer. By setting the P / Pd of each layer to approximately 4.5, the assembled core 4 can stretch approximately 20% in the cable longitudinal direction. The twist pitch P is the distance along the cable longitudinal direction between positions where any electric wire 3 is located at the same position in the cable circumferential direction. The layer core diameter Pd is the diameter of a circle passing through the center of the electric wires 3 in each layer, and is equal to the value obtained by subtracting the outer diameter of one electric wire 3 from the outer diameter of each layer.

[0019] Furthermore, each layer of the collective core 4 is twisted in the same direction, which makes it easier to stretch the collective core 4. The twisting direction is the direction in which the wires 3 rotate from one end to the other end of the cable 1 when viewed from one end of the cable 1.

[0020] (Bulk shield layer 5) The collective shielding layer 5 is provided so as to cover the collective core 4 collectively, and is provided between the collective core 4 and the sheath 6. In this embodiment, the collective shielding layer 5 is provided around the collective core 4 so as to be in direct contact with the collective core 4, and no pressure winding tape or inner sheath is provided between the collective shielding layer 5 and the collective core 4. This makes it possible to suppress the reduction in elongation that would be caused by providing a pressure winding tape or inner sheath, and to suppress an increase in the diameter of the cable 1. However, this is not limiting, and if the reduction in elongation of the cable 1 is not a problem, a pressure winding tape or inner sheath may be provided between the collective shielding layer 5 and the collective core 4. In this case, it is more preferable to use an inner sheath that is more easily stretched.

[0021] In this embodiment, the collective shield layer 5 is composed of a horizontally wound shield in which multiple metal wires 5a are wound horizontally. Like each layer of the collective core 4, the collective shield layer 5 also has a P / Pd ratio of 3 to 5. In this embodiment, the collective shield layer 5 is composed of 150 tin-plated copper foil threads with an outer diameter of 0.11 mm as the metal wires 5a, and the twist pitch P of the metal wires 5a is 29 mm, making P / Pd approximately 4.5. This makes the collective shield layer 5, like the collective core 4, more likely to stretch in the cable longitudinal direction.

[0022] To facilitate elongation in the cable longitudinal direction, the winding direction of the metal wires 5a of the collective shielding layer 5 is preferably the same as the twisting direction of the collective core 4. The winding direction of the metal wires 5a of the collective shielding layer 5 is the direction in which the metal wires 5a rotate from one end to the other end of the cable 1 when viewed from one end of the cable 1.

[0023] (Sheath 6) The sheath 6, like the central insert 2, is made of a material that is elastic and easily stretches in the longitudinal direction. In this embodiment, the sheath 6 is made of silicone rubber. As described above, the thickness of the sheath 6 is set to 5% or more of the outer diameter of the sheath 6. In this embodiment, the thickness of the sheath 6 is set to 0.9 mm, and the outer diameter of the sheath 6 is set to 8.4 mm.

[0024] (Actions and Effects of the Embodiments) As described above, the cable 1 according to this embodiment includes an aggregated core 4 formed by concentrically twisting a plurality of electric wires 3 in two or more layers around an elastic linear central filler 2, and an elastic sheath 6 covering the aggregated core 4, and in each layer of the aggregated core 4, P / Pd, which is the ratio of the layer core diameter Pd to the twist pitch P, is set to 3 or more and 5 or less.

[0025] This allows the thickness of the sheath 6 to be maintained at 5% or more of the outer diameter of the sheath 6, and the outer diameter of the sheath 6 to be maintained at a small diameter of 30 times or less the outer diameter of the electric wires 3, while still realizing a cable 1 that is easily stretchable in the cable longitudinal direction. That is, according to this embodiment, a stretchable cable 1 that has a small outer diameter and is easily stretchable can be realized. Furthermore, by setting P / Pd of each layer of the assembled core 4 to 3 or more and 5 or less, the flexibility of the cable 1 can be improved. Therefore, for example, even if the gap between the electric wires 3 is made smaller to further reduce the diameter, the flexibility of the cable 1 is not impaired.

[0026] (Other embodiments) FIG. 3(a) is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a cable 1a according to another embodiment of the present invention, and FIG. 3(b) is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a child strand 7.

[0027] As shown in Fig. 3(a), cable 1a is the same as cable 1 in Fig. 1(a), except that multiple child strands 7 are concentrically twisted in two or more layers around a central insert 2 to form an assembled core 4, and the collective shield layer 5 is formed of a braided shield. Note that although there are gaps between the child strands 7 in Fig. 3(a), it is also possible to configure the cable so that there are fewer gaps.

[0028] As shown in Figure 3(b), the child strand 7 is formed by twisting together multiple electric wires 3 (here, coaxial wires 30). Here, seven electric wires 3 are twisted around one electric wire 3, resulting in a total of eight electric wires 3 forming the child strand 7. To facilitate cable 1 elongation, the twisting direction of the child strand 7 should be the same as the twisting direction of the assembly core 4. The twisting direction of the child strand 7 is the direction in which the electric wires 3 rotate from one end to the other when viewed from one end of the child strand 7. Here, a coaxial wire 30 with an outer diameter of 0.34 mm, similar to that described in Figure 1(b), was used as the electric wire 3 to form the child strand 7 with an outer diameter of 1.12 mm. Note that while Figure 3(b) shows gaps between the electric wires 3, it is also possible to configure the child strand 7 to have fewer gaps. For example, twisting six electric wires 3 around one electric wire 3 would further reduce the gaps.

[0029] In cable 1a, to make cable 1a easier to stretch, the P / Pd of each layer made up of the child strands 7 that make up the assembly core 4 is set to be between 3 and 5. Here, nine child strands 7 are twisted around a central spacer 2 made of a rubber material with an outer diameter of 2.2 mm at a twist pitch P of 15 mm, and 14 child strands 7 are twisted around that at a twist pitch P of 25 mm, resulting in a P / Pd of approximately 4.5 for each layer. The outer diameter of the entire assembly core 4 is 6.7 mm.

[0030] In addition, in cable 1a, the collective shield layer 5 provided around the collective core 4 is composed of a braided shield made of metal wires 5a. Even when the collective shield layer 5 is composed of a braided shield, the ratio P / Pd, which is the ratio of the layer core diameter Pd to the twist pitch P, should be between 3 and 5, in order to facilitate longitudinal extension of the cable. The inclination angle of the metal wires 5a relative to the longitudinal direction of the cable should be 60° or greater. Here, the collective shield layer 5 was constructed with tin-plated copper foil threads having an outer diameter of 0.11 mm, 12 strands, 16 strands, and a twist pitch of 30 mm, resulting in a 7.2 mm collective shield layer. A 0.6 mm-thick silicone rubber sheath 6 is provided around the collective shield layer 5, and the outer diameter of the sheath 6 (the outer diameter of cable 1a) is 8.4 mm.

[0031] Even when the assembled core 4 is constructed by twisting the child strands 7 together in multiple layers, as in cable 1a, by setting the P / Pd of each layer of the assembled core 4 to be 3 or more and 5 or less, it is possible to realize cable 1a that has a small outer diameter and is easily stretchable.

[0032] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiments will be described by using the reference numerals and the like in the embodiments. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiments.

[0033] [1] A cable (1, 1a) comprising: an assembly core (4) formed by concentrically twisting a plurality of electric wires (3) or a plurality of child strands (7) formed by twisting a plurality of the electric wires (3) around an elastic linear central core (2) in two or more layers; and an elastic sheath (6) covering the assembly core (4), wherein the outer diameter of the sheath (6) is 30 times or less the outer diameter of the electric wires (3), the thickness of the sheath (6) is 5% or more of the outer diameter of the sheath (6), and in each layer of the assembly core (4), P / Pd, which is the ratio of the layer core diameter Pd to the twist pitch P, is 3 or more and 5 or less.

[0034] [2] The cable (1) according to [1], wherein a collective shielding layer (5) is formed between the collective core (4) and the sheath (6) by horizontally winding metal wires (5a), and in the collective shielding layer (5), P / Pd, which is the ratio of the layer core diameter Pd to the twist pitch P, is 3 or more and 5 or less.

[0035] [3] The cable (1) according to [2], wherein the winding direction of the metal wires (5a) of the collective shielding layer (5) and the twisting direction of the collective core (4) are the same direction.

[0036] [4] The cable (1a) according to [1], having an integrated shielding layer (5) formed by braiding metal wires (5a) between the collective core (4) and the sheath (6), wherein the ratio P / Pd of the layer core diameter Pd to the twist pitch P in the integrated shielding layer (5) is 3 or more and 5 or less.

[0037] [5] The cable (1a) according to [1], wherein the assembly core (4) is configured by concentrically twisting a plurality of the child strands (7) in two or more layers around the central insert (2), and the twisting direction of the child strands (7) is the same as the twisting direction of the assembly core (4).

[0038] [6] The cable (1, 1a) according to [1], wherein the number of the electric wires (3) constituting the collective core (4) is 64 or more.

[0039] [7] The cable (1, 1a) according to [1], wherein the electric wire (3) is a coaxial wire (30).

[0040] [8] The cable (1, 1a) according to [1], wherein the outer diameter of the electric wire (3) is 0.5 mm or less.

[0041] [9] The cable (1, 1a) according to [1], wherein the central insert (2) is made of a rubber material.

[0042] (Addendum) Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the above-described embodiments. It should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. Furthermore, the present invention can be appropriately modified and implemented within the scope of its spirit. [Explanation of symbols]

[0043] 1...Cable 2…Central intervention 3...Electric wire 30…Coaxial line 31...conductor 32...Insulator 33...Shield layer 34...Jacket 4...Collective Core 5...Bulk shield layer 5a…metal wire 6...Sheath 7... Sub-stranded wire

Claims

1. an aggregate core formed by concentrically twisting a plurality of electric wires or a plurality of child strands each formed by twisting a plurality of the electric wires around an elastic linear central core in two or more layers; an elastic sheath surrounding the collective core; The outer diameter of the sheath is 30 times or less the outer diameter of the electric wire, The thickness of the sheath is 5% or more of the outer diameter of the sheath, In each layer of the aggregate core, the ratio P / Pd of the layer core diameter Pd to the twist pitch P is 3 or more and 5 or less. cable.

2. a collective shield layer formed by horizontally winding metal wires between the collective core and the sheath; In the collective shield layer, P / Pd, which is a ratio of a layer core diameter Pd to a twist pitch P, is 3 or more and 5 or less. The cable of claim 1 .

3. the winding direction of the metal wires of the collective shield layer and the twisting direction of the collective core are the same direction; 3. The cable of claim 2.

4. a collective shield layer formed by braiding metal wires is provided between the collective core and the sheath; In the collective shield layer, P / Pd, which is a ratio of a layer core diameter Pd to a twist pitch P, is 3 or more and 5 or less. The cable of claim 1 .

5. the collective core is configured by concentrically twisting a plurality of the child strands in two or more layers around the central intermediate wire, The twisting direction of the child strands and the twisting direction of the assembly core are the same. The cable of claim 1 .

6. The number of the electric wires constituting the collective core is 64 or more. The cable of claim 1 .

7. The electric wire is a coaxial wire. The cable of claim 1 .

8. The outer diameter of the electric wire is 0.5 mm or less. The cable of claim 1 .

9. The central interposer is made of a rubber material. The cable of claim 1 .

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