JP2021136211A - cable - Google Patents

Abstract

To provide a cable that has a small diameter but has the resilience to quickly return to a straight line when a bending force is released.SOLUTION: A cable 1 comprises: a cable core 3 having a plurality of electric wires 2; a tubular covering layer 4 provided so as to cover the periphery of the cable core 3; a braided shield 5 provided so as to cover the periphery of the covering layer 4; and a sheath 6 provided so as to cover the periphery of the braided shield 5. The sheath 6 is provided in close contact with the braided shield 5.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cable.

As a cable used for wiring small electronic devices such as mobile phones and video cameras, or medical devices, a tape member is wrapped around a cable core in which a plurality of electric wires are bundled, and a braided shield and a sheath are formed around the cable core. (For example, see Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-152789

For example, in medical devices, a tube is inserted into the stomach through the mouth or nose, and liquid food or the like is directly injected into the stomach through the tube. The tube changes shape by being bent or straightened before it is inserted into the stomach. In such a tube, a striatum such as a stainless steel wire is built in. This striatum acts to quickly return to a straight line when the force for bending the tube is released when the shape of the tube changes from a bent state to a straight line state. The operability of is improved.

In recent years, when inserting the above-mentioned tube, a camera (imaging element) is provided at the tip of the tube so that the tube is not accidentally inserted into the trachea, and the tube is inserted while checking the image of the camera. Is being considered.

When the camera is provided on the tube described above, both a linear body such as a stainless steel wire and a cable used for wiring the camera or the like are mounted on the tube. Therefore, the structure of the tube becomes complicated and the diameter of the tube becomes large. As the outer diameter of the tube increases, the load on the human body also increases, so we want to reduce the outer diameter of the tube. Therefore, the present inventors have considered omitting a linear body such as a stainless steel wire and mounting only the cable on the tube. In this case, the cable is required to have a small diameter, but to have resilience that acts to quickly return to a straight line when the force for bending the tube is released.

Therefore, an object of the present invention is to provide a cable having a small diameter but having a resilience that quickly returns to a straight line when a bending force is released.

For the purpose of solving the above problems, the present invention covers a cable core having a plurality of electric wires, a tubular coating layer provided so as to cover the periphery of the cable core, and the periphery of the coating layer. Provided is a braided shield provided in the sword and a sheath provided so as to cover the periphery of the braided shield, the sheath provided in close contact with the braided shield.

According to the present invention, it is possible to provide a cable having a small diameter but having a resilience that quickly returns to a straight line when a bending force is released.

It is sectional drawing which shows the cross section perpendicular to the longitudinal direction of the cable which concerns on one Embodiment of this invention. (A) is a schematic configuration diagram of a cable assembly using the cable of FIG. 1, and (b) is a plan view of a tube.

[Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the cable according to the present embodiment. As shown in FIG. 1, the cable 1 covers the circumference of the cable core 3 having a plurality of electric wires 2, the tubular covering layer 4 provided so as to cover the periphery of the cable core 3, and the coating layer 4. A braided shield 5 provided in the above and a sheath 6 provided so as to cover the periphery of the braided shield 5 are provided.

The electric wire 2 has a conductor 21 and an insulator 22 provided so as to cover the periphery of the conductor 21. The conductor 21 is composed of a stranded conductor obtained by twisting a plurality of strands. As the wire, a wire made of copper or a copper alloy can be used. Further, as the conductor 21, a conductor made of a single wire can also be used. The outer diameter of the conductor 21 is 0.05 mm or more and 0.10 mm or less.

The insulator 22 is made of, for example, fluororesin, polyethylene, or the like. The thickness of the insulator 22 is 0.03 mm or more and 0.10 mm or less. The outer diameter of the insulator 22, that is, the outer diameter of the electric wire 2, is 0.10 mm or more and 0.30 mm or less. Here, the case where all the electric wires 2 constituting the cable core 3 are the same is shown, but the present invention is not limited to this, and electric wires 2 having different outer diameters, conductor cross-sectional areas, etc. may be included, for example. A coaxial wire having an outer conductor may be included in the electric wire 2.

In the present embodiment, four electric wires 2 are twisted together to form a cable core 3. However, the number of electric wires 2 constituting the cable core 3 is not limited to this. Further, a plurality of electric wires 2 may be arranged in parallel to form the cable core 3. However, when a plurality of electric wires 2 are arranged in parallel, it may be difficult to bend the cable 1 in a specific direction. Therefore, it is more desirable to twist the plurality of electric wires 2 to form the cable core 3. The outer diameter of the cable core 3 is 0.40 mm or more and 0.70 mm or less.

The coating layer 4 plays a role of holding the cable core 3 in a twisted state and a role of imparting a resilience to the cable 1 to quickly return to a straight line when a bending force is released. For example, it is conceivable to wind the tape member around the cable core 3 in a spiral shape, but in this case, when the cable 1 is bent, the tape member moves (expands and contracts) in the longitudinal direction of the cable and returns to a straight line. The restoring force to try is not obtained sufficiently. In the present embodiment, by providing the tubular covering layer 4, the cable 1 is provided with resilience (hereinafter, simply referred to as restorability) that quickly returns to a straight line when the bending force is released. There is.

The coating layer 4 is formed by molding a resin using extrusion molding so as to have a uniform (seamless) outer surface and inner surface in the circumferential direction and the longitudinal direction, and the outer shape thereof is formed into a tubular shape. It is an extruded layer. Further, the coating layer 4 is provided in a tubular shape so as to have a gap between the inner surface of the coating layer 4 that does not come into contact with the cable core 3 and the surface (outer surface) of the electric wire 2. Further, the coating layer 4 is provided in a tubular shape so that its outer surface is in contact with the inner surface of the braided shield 5 over the entire circumference. With such a configuration, in the cable 1, when the cable 1 is bent, the coating layer 4 is less likely to be crushed in the radial direction of the cable 1, and the cross section of the bent portion can have an elliptical shape. Then, a state in which there is a gap between the inner surface of the coating layer 4 and the outer surface of the electric wire 2 is maintained. At this time, in the coating layer 4, the force that causes the shape of the coating layer 4 to return to a tubular shape (to form a tubular shape in a linear state) with respect to the radial direction of the cable 1 (the direction from the coating layer 4 to the sheath 6). Restoring force to return) will be added. Therefore, the cable 1 can have a resilience that quickly returns to a straight line when the bending force is released.

The electric wire 2 may be in a state where it can move freely with respect to the coating layer 4. From the viewpoint of facilitating the development of resilience, it is preferable that the coating layer 4 is provided with a portion of the inner surface of the coating layer 4 in contact with the cable core 3 in close contact with the cable core 3. More specifically, in the coating layer 4, the cable core 3 is restrained so that the electric wire 2 cannot move freely in the coating layer 4, and even if the cable core 3 is pulled out from the coating layer 4 so as to be pulled out. It is provided in close contact with the cable core 3 to the extent that it does not come off. The coating layer 4 is provided so as to be in direct contact with the cable core 3, and no tape member or the like is provided between the coating layer 4 and the cable core 3. That is, the coating layer 4 is provided so as to cover the periphery of the cable core 3.

If the coating layer 4 is soft, sufficient resilience may not be obtained. Therefore, the coating layer 4 is preferably made of a relatively hard (small elongation) resin, and is more likely to be made of the same material as the sheath 6. preferable. Specifically, the coating layer 4 is preferably made of a fluororesin, and it is more preferable to use a fluororesin made of ETFE (tetrafluoroethylene / ethylene copolymer), which is relatively hard. In the present embodiment, the tubular coating layer 4 made of ETFE is formed by tube extrusion molding. The thickness of the coating layer 4 is preferably 0.05 mm or more and 0.15 mm or less in order for the coating layer 4 to play the role described above. In particular, it is effective that the thickness of the coating layer 4 is larger than the thickness of the braided shield 5 and smaller than the thickness of the sheath 6 in the above-mentioned range to play the above-mentioned role.

The braided shield 5 is formed by knitting metal strands. The braided shield 5 plays a role of shielding noise from the outside, a role of reinforcing the cable 1, and a role of imparting resilience to the cable 1 together with the sheath 6.

In order to reinforce the cable 1 and impart sufficient resilience to the cable 1, it is desirable that the metal wire used for the braided shield 5 is a hard metal wire, and a hard copper alloy wire having high strength. Is more desirable to use. More specifically, as the metal wire used for the braided shield 5, it is preferable to use a hard copper alloy wire having a tensile strength of 800 MPa or more and an elongation of 1% or more and 3% or less. By setting the elongation of the metal wire to 1% or more, it is possible to prevent the metal wire from breaking when the cable 1 is bent, and by setting the elongation of the metal wire to 3% or less, the metal It is possible to suppress a decrease in the resilience of the cable 1 due to the elongation of the wire. As the copper alloy wire used for the metal element wire, for example, a copper alloy wire containing tin, a copper alloy wire containing a predetermined amount of tin and indium, a copper alloy wire such as a copper alloy wire containing a predetermined amount of silver, or the like may be used. can. The outer diameter of the metal wire is 0.03 mm or more and 0.05 mm or less.

The braid density of the braided shield 5 is preferably 90% or less, more preferably 80% or less. As a result, the sheath 6 can easily enter the gap (stitch) between the metal wires of the braided shield 5, and the adhesion between the sheath 6 and the braided shield 5 is improved. As a result, the resilience of the cable 1 is further improved. When the braid density is 80% or less, the sheath 6 is more likely to enter the gap of the braid shield 5 than when the braid density is larger than 80% and 90% or less, so that the sheath 6 and the braid shield 5 are in close contact with each other. The sex is further improved. From the viewpoint of achieving both the shield characteristics of the braided shield 5 and the adhesion to the sheath 6, the braided density is preferably 70% or more.

Further, in the present embodiment, the braided shield 5 is not in close contact with the coating layer 4, and is provided so as to be movable with respect to the coating layer 4 in the longitudinal direction of the cable. More specifically, although the braided shield 5 is in contact with the coating layer 4, the metal wire constituting the braided shield 5 is not in a state of biting into the coating layer 4, and is integrated with the coating layer 4. It is not composed of. As a result, the flexibility of the cable 1 can be ensured, and the resilience of the cable 1 can be improved while giving the cable 1 suppleness.

The sheath 6 serves as a protective layer for protecting the cable core 3 and the braided shield 5, and also plays a role of imparting resilience to the cable 1 together with the braided shield 5.

In this embodiment, the sheath 6 is provided in close contact with the braided shield 5. Specifically, the sheath 6 is provided so that a part thereof enters the gap (stitch) between the wires constituting the braided shield 5. As a result, even if the braided shield 5 or the sheath 6 is pulled so as to be pulled out in the longitudinal direction of the cable, the braided shield 5 and the sheath 6 cannot move relative to each other in the longitudinal direction of the cable. And the sheath 6 try to move together. By providing the sheath 6 in close contact with the braided shield 5 in this way, when the force for bending the cable 1 is released, the braided shield 5 and the sheath 6 are in the state before bending. The force to return is increased, and the resilience of the cable 1 can be improved.

In order to further improve the resilience of the cable 1, it is desirable that the sheath 6 is made of a relatively hard resin like the coating layer 4. Specifically, the sheath 6 is preferably made of a fluororesin such as ETFE. The sheath 6 may be formed by full extrusion or insertion extrusion so that the sheath 6 can easily enter the gap (stitch) between the wires constituting the braided shield 5. The thickness of the sheath 6 is 0.03 mm or more and 0.12 mm or less. The outer diameter of the sheath 6, that is, the outer diameter of the cable 1 is 1.10 mm or less.

FIG. 2A is a schematic configuration diagram of a cable assembly 10 using the cable 1. As shown in FIG. 2, the cable assembly 10 is provided with an image sensor 11 at one end of the cable 1 and is connected to a computer or the like that receives an image signal from the image sensor 11 at the other end. A connector 12 such as a flexible printed circuit board is provided.

The cable assembly 10 is mounted on a tube 13 as shown in FIG. 2 (b). The tube 13 is used, for example, for being inserted into the stomach through the mouth or nose, and is formed to have a small diameter such as an inner diameter of about 1.2 mm and an outer diameter of about 2.2 mm. The cable assembly 10 is formed by passing the cable 1 through the hollow portion of the tube 13 and providing the image sensor 11 and the connector 12 at each end of the cable 1. Although it is desirable that the outer diameter of the tube 13 is small, the thickness of the tube 13 is required to some extent in order to secure the resilience and operability of the tube 13 itself. Therefore, the outer diameter of the tube 13 is about 2.0 mm or more and 2.4 mm or less, the inner diameter of the tube 13 is about 1.0 mm or more and 1.2 mm or less, and the thickness of the tube 13 is about 0.4 mm or more and 0.7 mm or less. ..

(Actions and effects of embodiments)
As described above, the cable 1 according to the present embodiment includes a tubular covering layer 4 provided so as to cover the periphery of the cable core 3, and the sheath 6 is in close contact with the braided shield 5. It is provided.

By providing the tubular covering layer 4 and providing the sheath 6 in close contact with the braided shield 5, the cable is compared with the case where the tape member is spirally wound around the cable core 3 as in the conventional case. It is possible to greatly improve the resilience of 1. In particular, by providing the coating layer 4 in close contact with the cable core 3, the cable 1 is provided with further resilience, and although it has a small diameter, it quickly returns to a straight line when the bending force is released. It becomes possible to realize a cable 1 having high resilience.

Further, when mounting the cable 1 on a tube or the like, it is necessary to pass the cable 1 through a narrow hole provided in the tube or the like. It is possible to realize a cable 1 that can be easily passed through a narrow hole and can be easily mounted on a tube or the like. For example, when the tube is disposable, it is necessary to insert the cable 1 into the hole of the tube frequently, but even in such a case, it is easy to insert the cable 1 into the hole of the tube, which is a burden on the operator. Can be reduced.

(Summary of embodiments)
Next, the technical concept grasped from the above-described embodiment will be described with reference to the reference numerals and the like in the embodiment. However, the respective reference numerals and the like in the following description are not limited to the members and the like in which the components in the claims are specifically shown in the embodiment.

[1] A cable core (3) having a plurality of electric wires (2), a tubular coating layer (4) provided so as to cover the periphery of the cable core (3), and the coating layer (4). A braided shield (5) provided to cover the periphery and a sheath (6) provided to cover the periphery of the braided shield (5) are provided, and the sheath (6) is provided with the braided shield (6). A cable (1) provided in close contact with 5).

[2] The cable (1) according to [1], wherein a part of the sheath (6) is provided so as to enter a gap between metal wires constituting the braided shield (5).

[3] The cable (1) according to [2], wherein the braid density of the braided shield (5) is 90% or less.

[4] The cable (1) according to any one of [1] to [3], wherein the braided shield (5) is provided so as to be movable in the longitudinal direction of the cable with respect to the coating layer (4). ).

[5] The cable (1) according to any one of [1] to [4], wherein the coating layer (4) is made of a fluororesin.

[6] Any one of [1] to [5], wherein the coating layer (4) has a thickness larger than the thickness of the braided shield (5) and smaller than the thickness of the sheath (6). Cable (1) described in.

[7] The cable (1) according to any one of [1] to [6], wherein the braided shield (5) is made of a hard metal wire.

Although the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. It should also be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

The present invention can be appropriately modified and implemented without departing from the spirit of the present invention. For example, in the above embodiment, as an example, a case where the cable 1 is mounted on a tube inserted into the stomach through the mouth or nose and the cable 1 is used as wiring for a camera provided at the tip of the tube has been described. The use of the cable 1 is not limited to this. The cable 1 can be suitably used, for example, in an application in which the cable 1 is inserted and wired in an extremely narrow hole-shaped wiring space.

1 ... Cable 2 ... Electric wire 3 ... Cable core 4 ... Coating layer 5 ... Braided shield 6 ... Sheath 21 ... Conductor 22 ... Insulator

Claims (7)

A cable core with multiple wires and
A tubular covering layer provided so as to cover the periphery of the cable core, and
A braided shield provided so as to cover the periphery of the coating layer,
A sheath provided so as to cover the periphery of the braided shield is provided.
The sheath is provided in close contact with the braided shield.
cable. The sheath is provided so that a part thereof enters the gap between the metal wires constituting the braided shield.
The cable according to claim 1. The braid density of the braid shield is 90% or less.
The cable according to claim 2. The braided shield is provided so as to be movable in the longitudinal direction of the cable with respect to the coating layer.
The cable according to any one of claims 1 to 3. The coating layer is made of fluororesin.
The cable according to any one of claims 1 to 4. The coating layer has a thickness greater than the thickness of the braided shield and less than the thickness of the sheath.
The cable according to any one of claims 1 to 5. The braided shield is made of a hard metal wire.
The cable according to any one of claims 1 to 6.

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