JP7452098B2 - cable - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to cables.

Cables used for wiring small electronic devices such as mobile phones and video cameras, or medical devices are made by wrapping a tape member around a cable core made by bundling multiple wires, and surrounding it with a braided shield and sheath. A cable in which the following are sequentially provided is used (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2013-152789

For example, in medical equipment, a tube is inserted into the stomach through the mouth or nose, and liquid food or the like is injected directly into the stomach through the tube. The shape of the tube changes by being bent or straightened before it is inserted into the stomach. Such a tube has a built-in filament such as a stainless steel wire. When the shape of the tube changes from a bent state to a straight state, these filaments act to quickly return the tube to its straight state when the force to bend the tube is released. Improves operability.

In recent years, when inserting the above-mentioned tube, a camera (imaging device) is installed at the tip of the tube to prevent the tube from being accidentally inserted into the trachea, and the tube is inserted while checking the camera image. is being considered.

When a camera is installed in the above-mentioned tube, both a linear body such as a stainless steel wire and a cable used for wiring the camera etc. are mounted on the tube. Therefore, the structure of the tube becomes complicated and the diameter of the tube increases. As the outer diameter of the tube increases, the load on the human body also increases, so it is desirable to reduce the outer diameter of the tube. Therefore, the present inventors thought of omitting the 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 restorability so that it quickly returns to its straight shape when the force for bending the tube is released, even though it has a small diameter.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a cable that has a small diameter but has the ability to quickly return to a straight line when the bending force is released.

In order to solve the above problems, the present invention provides a cable core having a plurality of electric wires, a cylindrical coating layer provided to cover the periphery of the cable core, and a cylindrical coating layer provided to cover the periphery of the coating layer. A cable is provided, comprising: a braided shield provided on the cable; and a sheath provided to cover the periphery of the braided shield, the sheath being provided in close contact with the braided shield.

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

FIG. 2 is a sectional view showing a cross section perpendicular to the longitudinal direction of a cable according to an embodiment of the present 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]
Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a 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 includes a cable core 3 having a plurality of electric wires 2, a cylindrical coating layer 4 provided to cover the periphery of the cable core 3, and a cylindrical coating layer 4 provided to cover the periphery of the coating layer 4. A sheath 6 is provided to cover the periphery of the braided shield 5.

The electric wire 2 includes a conductor 21 and an insulator 22 provided so as to cover the periphery of the conductor 21. The conductor 21 is made of a twisted wire conductor made by twisting a plurality of wires together. As the wire, one made of copper or a copper alloy can be used. Moreover, as the conductor 21, one 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. Further, 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, a case is shown in which all the electric wires 2 constituting the cable core 3 are the same, but the 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 line with an outer conductor may be included in the wire 2.

In this embodiment, the cable core 3 is configured by twisting four electric wires 2 together. However, the number of electric wires 2 constituting the cable core 3 is not limited to this. Further, the cable core 3 may be configured by arranging a plurality of electric wires 2 in parallel. However, if a plurality of electric wires 2 are arranged in parallel, it may become difficult to bend the cable 1 in a specific direction, so it is more desirable to configure the cable core 3 by twisting a plurality of electric wires 2 together. The outer diameter of the cable core 3 is 0.40 mm or more and 0.70 mm or less.

The covering layer 4 serves to hold the cable core 3 in a twisted state, and to provide the cable 1 with the ability to quickly return to a straight line when the bending force is released. For example, it is conceivable to wrap a tape member spirally around the cable core 3, 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. It is not possible to obtain sufficient resiliency. In this embodiment, by providing the cylindrical coating layer 4, the cable 1 is given the restoring property (hereinafter simply referred to as restoring property) of quickly returning to a straight line when the bending force is released. There is.

The coating layer 4 is formed by molding resin using extrusion molding to have a uniform (unbroken) outer surface and inner surface in the circumferential direction and longitudinal direction, and the outer shape is formed into a cylindrical shape. This is the extruded layer. Further, the covering layer 4 is provided in a cylindrical shape so that there is a gap between the inner surface of the covering layer 4 that does not contact the cable core 3 and the surface (outer surface) of the electric wire 2. Furthermore, the covering layer 4 is provided in a cylindrical shape so that its outer surface is in contact with the inner surface of the braided shield 5 over the entire circumference. With the cable 1 having such a configuration, the coating layer 4 is not easily crushed in the radial direction of the cable 1 when the cable 1 is bent, and the cross section of the bent portion can have an elliptical shape. Then, a gap is maintained between the inner surface of the coating layer 4 and the outer surface of the electric wire 2. At this time, in the coating layer 4, there is a force that causes the shape of the coating layer 4 to return to the cylindrical shape (to return to the cylindrical shape in the straight state) in the radial direction of the cable 1 (direction from the coating layer 4 to the sheath 6). It becomes a state where a restoring force that tries to return is applied. Therefore, the cable 1 can have the ability to quickly return 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 making it easier to express resilience, it is preferable that the inner surface of the coating layer 4 is provided so that the portion that comes into contact with the cable core 3 is in close contact with the cable core 3. More specifically, the covering layer 4 restrains the electric wire 2 so that it cannot move freely within the covering layer 4, and the cable core 3 does not move even if the cable core 3 is pulled out from the covering layer 4. It is provided in close contact with the cable core 3 to the extent that it does not come off. Note that the covering 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 covering layer 4 and the cable core 3. That is, the covering layer 4 is provided so as to cover the periphery of the cable core 3.

If the covering layer 4 is soft, sufficient resilience may not be obtained, so the covering layer 4 is preferably made of a relatively hard (low elongation) resin, and preferably made of the same material as the sheath 6. preferable. Specifically, the coating layer 4 is preferably made of a fluororesin, and among fluororesins, it is more preferable to use one made of relatively hard ETFE (tetrafluoroethylene/ethylene copolymer). In this embodiment, the cylindrical covering layer 4 made of ETFE was 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 fulfill the above-mentioned role. In particular, it is effective for the thickness of the covering layer 4 to be larger than the thickness of the braided shield 5 and smaller than the thickness of the sheath 6 within the above-mentioned range to fulfill the above-mentioned role.

The braided shield 5 is constructed by interweaving metal wires. The braided shield 5 plays the roles of shielding noise from the outside, reinforcing the cable 1, and providing resilience to the cable 1 together with the sheath 6.

In order to reinforce the cable 1 and provide sufficient resilience to the cable 1, the metal wire used for the braided shield 5 is preferably a hard metal wire, and a hard copper alloy wire with high strength is preferably used. It 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 suppress the metal wire from breaking when bending the cable 1, and by setting the elongation of the metal wire to 3% or less, the metal wire can be prevented from breaking when the cable 1 is bent. It is possible to suppress deterioration in the restorability of the cable 1 due to elongation of the strands. As the copper alloy wire used as the metal 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 containing a predetermined amount of silver, etc. can 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. Thereby, the sheath 6 can easily fit into the gaps (knits) 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. Note that when the braid density is 80% or less, the sheath 6 enters into the gap between the braided shields 5 more easily than when the braid density is greater than 80% and 90% or less, so the tight contact between the sheath 6 and the braided shield 5 is reduced. further improves sex. From the viewpoint of achieving both shielding properties of the braided shield 5 and adhesion to the sheath 6, the braid density is preferably 70% or more.

Further, in this embodiment, the braided shield 5 is not in close contact with the coating layer 4, but is provided so as to be movable in the longitudinal direction of the cable with respect to the coating layer 4. More specifically, although the braided shield 5 is in contact with the coating layer 4, the metal wires constituting the braided shield 5 are not in a state of digging into the coating layer 4, but are integrated with the coating layer 4. It is not structured as follows. Thereby, the bendability of the cable 1 can be ensured, and while giving flexibility to the cable 1, it becomes possible to improve the resilience of the cable 1.

The sheath 6 serves as a protective layer that protects the cable core 3 and the braided shield 5, and also serves to provide 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 portion thereof enters the gaps (knits) between the strands forming the braided shield 5. As a result, even if the braided shield 5 or sheath 6 is pulled out in the longitudinal direction of the cable, the braided shield 5 and sheath 6 cannot move relative to each other in the longitudinal direction of the cable. and sheath 6 try to move together. As described above, since the sheath 6 is provided in close contact with the braided shield 5, when the force trying to bend the cable 1 is released, the braided shield 5 and the sheath 6 are returned to the state before bending. The force that tries to return becomes larger, making it possible to improve the resilience of the cable 1.

In order to further improve the resilience of the cable 1, it is desirable that the sheath 6 be made of a relatively hard resin, similar to the covering layer 4. Specifically, the sheath 6 is preferably made of a fluororesin such as ETFE. In order for the sheath 6 to easily enter the gaps (knits) between the wires constituting the braided shield 5, the sheath 6 is preferably formed by solid extrusion or insertion extrusion. 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, ie, the outer diameter of the cable 1, is 1.10 mm or less.

FIG. 2(a) is a schematic configuration diagram of a cable assembly 10 using the cable 1. As shown in FIG. As shown in FIG. 2, the cable assembly 10 includes an image sensor 11 provided at one end of the cable 1, and a device for connecting to a computer or the like that receives image signals 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, to be inserted into the stomach through the mouth or nose, and has a small diameter of, for example, about 1.2 mm in inner diameter and about 2.2 mm in outer diameter. The cable assembly 10 is formed by passing the cable 1 through the hollow part of the tube 13 and providing an image pickup element 11 and a connector 12 at each end of the cable 1. Although it is desirable to make the outer diameter of the tube 13 small, the tube 13 needs to have a certain thickness in order to ensure the restorability 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 the cylindrical coating layer 4 provided to cover the cable core 3, and the sheath 6 is in close contact with the braided shield 5. It is provided.

By providing the cylindrical coating layer 4 and providing the sheath 6 in close contact with the braided shield 5, the cable can be easily It becomes possible to greatly improve the restorability of 1. In particular, by providing the covering layer 4 in close contact with the cable core 3, the cable 1 is given further resilience, and despite its small diameter, it quickly returns to a straight shape when the bending force is released. It becomes possible to realize a cable 1 with high resilience.

Furthermore, 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, but in the cable 1 according to the present embodiment, it is easy to return to a straight line. It is possible to realize a cable 1 that can easily pass through narrow holes 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 in the tube frequently, but even in such cases, it is easier to insert the cable 1 into the hole in the tube, reducing the burden on the operator. It becomes possible to reduce the

(Summary of embodiments)
Next, technical ideas understood from the embodiments described above will be described using reference numerals and the like in the embodiments. However, each reference numeral in the following description does not limit the constituent elements in the claims to those specifically shown in the embodiments.

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

[2] The cable (1) according to [1], wherein the sheath (6) is provided so that a portion of the sheath (6) enters a gap between metal wires forming 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 movably 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 covering layer (4) has a thickness greater than the thickness of the braided shield (5) and less 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. Furthermore, it should be noted that not all combinations of features described in the embodiments are essential for solving the problems of the invention.

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

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

Claims (7)

a cable core having a plurality of wires;
a cylindrical covering layer provided to cover the periphery of the cable core;
a braided shield provided to cover the periphery of the coating layer;
a sheath provided to cover the periphery of the braided shield,
The sheath is provided in close contact with the braided shield,
The covering layer and the sheath are extruded layers made of the same resin,
cable. The sheath is provided so that a portion thereof enters a gap between the metal wires forming the braided shield.
The cable according to claim 1. The braid density of the braided shield is 70% or more and 80% 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 same resin is a fluororesin;
The cable according to any one of claims 1 to 4. The covering layer has a thickness of 0.05 mm or more and 0.15 mm or less, and greater than the thickness of the braided shield and smaller 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 having a tensile strength of 800 MPa or more and an elongation of 1% or more and 3% or less .
The cable according to any one of claims 1 to 6.

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