CN118197682A - Cable and method for manufacturing same - Google Patents

Abstract

The invention provides a multi-core cable and a manufacturing method thereof, which is easy to bend with a small bending radius and can maintain a bending state. The cable (1) is provided with a cable core (3) formed by twisting a plurality of wires (2) in a multi-layer structure, a belt member (4) spirally wound around the cable core (3), and a sheath (6) covering the periphery of the belt member (4), and the wires (2) constituting the outermost layer of the cable core (3) have a bending portion (2 a) which is locally bent in a convex shape so as to protrude at least in the cable circumferential direction.

Description

Cable and method for manufacturing same

Technical Field

The invention relates to a cable and a manufacturing method thereof.

Background

As a countermeasure for improving productivity of factories and the like, industrial robots such as man-machine-cooperative robots and small-sized multi-joint robots are becoming widespread. As cables used for the industrial robot, there are a movable part cable wired to a movable part of the industrial robot and a fixed part cable connecting the industrial robot to a control device or the like. Among them, as a cable used as a cable for a fixing portion, there is, for example, a multi-core cable having a cable core formed by twisting a plurality of (for example, 40 or more) insulated wires around a cable center in a multi-layer (for example, 2 or more) layer structure.

Patent document 1 is one of prior art document information related to the present application.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2022-048495

Disclosure of Invention

Problems to be solved by the invention

The length of the cable for the fixing portion between the industrial robot and the control device is, for example, 20m or more, and is very long. Therefore, it is desirable that the cable for the fixing portion before wiring be bundled and compactly housed in the housing case or the like. Further, when the cables for the fixing portion are routed, the cables may be routed in a state where the remaining length portions of the cables are bundled, and from the viewpoint of saving space in the routing portion, it is desirable to reduce the inner diameter of the cables for the fixing portion bundled (for example, the inner diameter is set to about 200 mm).

However, when the cable for the fixing portion is a multicore cable having a cable core formed by twisting a plurality of insulated wires in a multilayer structure, it may be difficult to bend the cable with a small bending radius. Further, even if the fixing portion including the multicore cable is forcibly bent and bundled with a small bending radius, the inner diameter of the bundling is naturally increased by bouncing, and a holding member or the like is required to keep the inner diameter of the bundling small.

Accordingly, an object of the present invention is to provide a multicore cable and a method of manufacturing the same, which are easy to bend with a small bending radius and can maintain a bent state.

Means for solving the problems

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a cable including a cable core formed by twisting a plurality of insulated wires in a multi-layered layer structure, a tape member spirally wound around the cable core, and a sheath covering the periphery of the tape member, wherein the insulated wires constituting the outermost layer of the cable core have a curved portion that is locally curved in a convex shape.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for manufacturing a cable, including a step of forming a cable core by twisting a plurality of insulated wires in a multi-layered layer structure, a step of spirally winding a tape member around the cable core, a step of providing a sheath covering the periphery of the tape member, and a step of forming a bent portion; in the step of forming the bent portion, the cable base after the sheath is formed is forcibly bent via a pulley having an outer diameter equal to or smaller than a strand pitch of the cable core, thereby forming a bent portion locally bent in a convex shape in the insulated wire constituting the outermost layer of the cable core.

Effects of the invention

According to the present invention, it is possible to provide a multicore cable and a method of manufacturing the same, which are easy to bend with a small bending radius and can maintain a bent state.

Drawings

Fig. 1 is a view showing a cable according to an embodiment of the present invention, (a) is a sectional view showing a section perpendicular to a cable longitudinal direction, and (b) is a view showing an appearance of a cable core when a tape member, a shield layer, and a sheath are removed.

Fig. 2 is a diagram illustrating the formation of a bent portion.

In fig. 3, (a) is a side view of the bundled cable, and (b) is a top view thereof.

Description of the reference numerals

1 … Cable, 1a … cable matrix, 2 … wires (insulated wires), 2a … bends, 3 … cable cores, 4 … ribbon members, 5 … shielding layers, 6 … jackets, 7 … center filler, 8 … pulleys.

Detailed Description

Embodiment(s)

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a view showing a cable 1 according to the present embodiment, (a) is a cross-sectional view showing a cross-section perpendicular to the cable longitudinal direction, and (b) is a view showing an appearance of a cable core 3 when a tape member 4, a shield layer 5, and a sheath 6 are removed. The cable 1 is used as a cable for a fixing portion for connecting an industrial robot to a control device or the like in a factory or the like, for example.

As shown in fig. 1 (a) and (b), the cable 1 includes a cable core 3 formed by twisting a plurality of insulated wires (hereinafter, simply referred to as wires) 2 in a multi-layer (2-layer or more) structure, a tape member 4 wound around the cable core 3, a shield layer 5 covering the periphery of the tape member 4, and a sheath 6 covering the periphery of the shield layer 5.

(Cable core 3)

The electric wire 2 has a conductor 21 and an insulator 22 covering the periphery of the conductor 21. The conductor 21 is a stranded conductor formed by stranding a plurality of bare metal wires having an outer diameter of 0.08mm or more and 0.30mm or less. In the present embodiment, 30 bare metal wires each composed of a tin-plated annealed copper wire having an outer diameter of 0.18mm were collectively twisted to form the conductor 21. The strand pitch P of the conductor 21 is, for example, 5mm or more and 40mm or less. The outer diameter of the conductor 21 is 0.5mm or more and 2.0mm or less. The strand pitch P is a distance along the cable longitudinal direction at a position where the positions in the cable circumferential direction are the same in any of the electric wires 2.

As the insulator 22, an insulator composed of a polyvinyl chloride resin composition is used. The thickness of the insulator 22 is, for example, 0.2mm or more and 0.5mm or less. In order to form a bending portion 2a described later in the electric wire 2 to facilitate bending of the cable 1 with a small bending radius, the elongation of the insulator 22 may be 150% or more.

The cable core 3 is formed by twisting a plurality of wires 2 so as to have a multilayer structure. In the present embodiment, the plurality of wires 2 are helically twisted around the center filler 7 disposed in the center of the cable to form the cable core 3. More specifically, as shown in fig. 1 (a), for example, the following cable core 3 can be used: the center filler 7 is formed by twisting 8 wires 2 around the center filler 7 as a first layer, further twisting 14 wires 2 around the first layer as a second layer, further twisting 20 wires 2 around the second layer as a third layer, and twisting the wires 2 in three layers. At this time, the number of the electric wires 2 constituting the cable core 3 was 42 in total.

The wires 2 of the layers are twisted in the same direction. The cable core 3 has an outer diameter of 8mm to 13 mm. The number of the wires 2 constituting the cable core 3 is 42, but the number of the wires 2 constituting the cable core 3 is not limited to this. However, with respect to the effect (effect that the cable 1 is easily bent with a small bending radius and can maintain a bent state) of the present embodiment described later, the larger the number of wires 2 and the thicker the cable core 3, the more remarkable the effect is, and particularly when the cable core 3 is constituted by a three-layer or more layer structure, the larger the force to return the cable 1 to the original shape (shape before bending) becomes when the cable 1 is bent with a small bending radius. Therefore, in the case where the cable core 3 is constituted by a three-layer or more layer structure, a more remarkable effect can be obtained. In the case where the cable core 3 is configured by a three-layer or more layer structure, the number of the electric wires 2 configuring the third layer is preferably 18 or more. By setting the number of the wires 2 constituting the third layer to 18 or more, the bent portion 2a is easily formed in the wires 2 constituting the outermost layer of the cable core 3.

The ratio of the layer core diameter PD of the outermost layer (here, the third layer) of the cable core 3 to the strand pitch P of the electric wire 2, that is, P/PD, may be 17 or more and 22 or less. The bent portion 2a described later is easily formed by the P/PD of 17 or more (details about the bent portion 2a will be described later). In addition, when the P/PD is 22 or less, buckling of the cable 1 can be suppressed when the cable 1 is bent.

In the present embodiment, the plurality of wires 2 constituting the cable core 3 are all the same, but the present invention is not limited thereto, and the cable core 3 may include wires 2 having different outer diameters and structures, for example, coaxial wires, twisted pairs, or the like.

The center-fill 7 is formed by bundling a plurality of fibrous bodies (filaments), for example. In the present embodiment, 10 pieces of 10-numbered spun yarn are bundled as the center filler 7. The material and number of filaments constituting the center-fill 7 are not limited to this. The center filler 7 is disposed only in the center of the cable, and is not disposed between the wires 2 of the respective layers and between the wires 2 and the belt member 4. The center filler 7 is disposed so as to enter between the wires 2 constituting the first layer of the cable core 3 (between the wires 2 adjacent in the cable circumferential direction in the first layer). The center filler 7 may not be a fibrous body (filament), and may be a resin tube, for example.

(With component)

Around the cable core 3, a tape member 4 is spirally wound. The tape member 4 functions to keep the twisting of the cable core 3 from untwisting, and is wound in a spiral shape around the cable core 3 so that a part thereof in the width direction overlaps. As the belt member 4, a belt made of paper or nonwoven fabric or a resin belt made of a resin such as polyethylene can be used.

The winding direction of the tape member 4 is opposite to the twisting direction of the cable core 3. Thus, the electric wire 2 constituting the outermost layer of the cable core 3 is easily moved relative to the belt member 4, and a bent portion 2a described later is easily formed. The winding direction of the tape member 4 is a direction in which the tape member 4 rotates from the other end to one end of the cable 1. In addition, the twisting direction of the cable core 3 means a direction in which the electric wire 2 rotates from the other end to one end of the cable 1.

(Shielding layer 5)

The shielding layer 5 is provided so as to cover the periphery of the belt member 4. The shield layer 5 is formed of a braided shield formed by braiding bare metal wires made of copper or copper alloy. As the shielding layer 5, for example, a braided shield may be used in which a plurality of first metal bare wires made of aluminum or an aluminum alloy and a plurality of second metal bare wires made of copper or a copper alloy are braided so that the first metal bare wires and the second metal bare wires intersect. This can reduce the weight of the shield layer 5 as compared with a braided shield made of only bare metal wires made of copper or copper alloy.

(Sheath 6)

The sheath 6 is provided to protect the shield layer 5 and the cable core 3, and is provided so as to cover the periphery of the shield layer 5. In the present embodiment, the sheath 6 made of a polyvinyl chloride resin composition is used. The thickness of the sheath 6 is about 1.0 mm. The thickness of the sheath 6 is not limited to this, and may be, for example, 0.8mm or more and 2.0mm or less. The sheath 6 may have a tensile strength of 12MPa or more and an elongation of 200% or more.

(Bending portion 2 a)

As shown in fig. 1b, in the cable 1 of the present embodiment, the electric wire 2 constituting the outermost layer (here, the third layer) of the cable core 3 has a curved portion 2a that is locally curved in a convex shape. Since the cable 1 is bent by providing the bending portion 2a, the wire 2 of the outermost layer of the cable core 3 having the largest tensile force when bending the cable 1 can have a margin length, the cable 1 can be easily bent, and the cable 1 can be easily maintained in a bent state. That is, by providing the bending portion 2a, even the multi-core cable 1 is easy to bend the cable 1 with a small bending radius, and the bundled state can be maintained when the cables 1 are bundled with a small bending radius.

The bent portions 2a are formed at random in the cable longitudinal direction and the cable circumferential direction, and are formed so as to protrude at least in the cable circumferential direction so as to follow the inner circumferential surface of the belt member 4. The bent portion 2a may be further formed to protrude outward in the cable radial direction. In particular, in order to significantly obtain the effect of the present embodiment (the effect that the cable 1 is easily bent with a small bending radius and can maintain the bent state) described later, when the plurality of wires 2 constituting the outermost layer of the cable core 3 are twisted with a predetermined twist pitch P, the plurality of wires 2 constituting the outermost layer of the cable core 3 preferably each have at least one bending portion 2a within a predetermined twist pitch P (for example, 200 mm) with respect to the cable longitudinal direction. The size of the bent portion 2a is also determined by the thickness of the electric wire 2 and the size of the cable core 3 (layer core diameter PD), but may be a size to which a convex portion (i.e., the bent portion 2 a) is visually confirmed to be present in the electric wire 2. More specifically, in the convex portion of the bent portion 2a, the height h from the surface of the electric wire 2 in the portion where the bent portion 2a is not present to the top of the convex portion is 0.2 to 0.5 times the outer diameter of the electric wire 2. If the height h is 0.2 to 0.5 times the outer diameter of the electric wire 2, the cable 1 is easily bent with a small bending radius, and breakage and waving of the electric wire 2 during bending can be suppressed. In order to obtain the above-described effect, the number of wires 2 of 30% or more and 50% or less of the plurality of wires 2 (20 wires in fig. 1) constituting the outermost layer of the cable core 3 may have the bent portion 2a in an arbitrary cross section perpendicular to the cable length direction. By providing the bending portion 2a at the outermost layer of the cable core 3, as shown in fig. 1 (b), a gap 31 is formed between adjacent wires 2, and the wires 2 can move in the circumferential direction of the cable 1 when the cable 1 is bent at a small bending radius through the gap 31. Thus, when the cable 1 is bent with a small bending radius and bundled, the force required to restore the cable 1 can be reduced, and the bundled state can be maintained.

(Method for producing Cable 1)

In manufacturing the cable 1, first, the electric wire 2 is twisted around the center filler 7 to form the cable core 3, the tape member 4 is spirally wound around the cable core 3, the shield layer 5 is formed around the tape member 4, and the sheath 6 is formed around the shield layer 5. Thus, the cable 1 (referred to as a cable base 1 a) in which the bent portion 2a is not formed in the cable core 3 is obtained. At this time, in the cable core 3 constituting the cable base 1a, the plurality of electric wires 2 are preferably arranged in a state where there is no gap with respect to the circumferential direction and the radial direction of the cable core 3 (a state where the electric wires 2 are in contact with each other). Then, a step of forming the bent portion 2a is performed.

In the step of forming the bent portion 2a, as shown in fig. 2, the cable base 1a is forcibly bent at a small bending radius via the pulley 8 having a small outer diameter. As the pulley 8, a pulley having an outer diameter D of 1/2 or less of the strand pitch P of the cable core 3 may be used. In particular, as the pulley 8, a pulley having an outer diameter D of 25 times to 35 times the outer diameter of the cable base 1a may be used. Thereby, the bent portions 2a are formed in the plurality of electric wires 2 constituting the outermost layer of the cable core 3. In addition, only one pulley 8 is shown here, but a plurality of pulleys 8 may be used. By using a plurality of pulleys 8, the bent portion 2a is formed more easily than in the case of using one pulley 8. By forcibly bending the cable base 1a with a small bending radius, the electric wires 2 constituting the outermost layer of the cable core 3 are expanded outward in the cable radial direction. However, the cable core 3 is covered with the tape member 4, the shielding layer 5, and the sheath 6, and there is no space for the electric wires 2 to retreat radially outside the cable. Accordingly, the electric wire 2 can retreat in the cable circumferential direction only along the inner circumferential surface of the belt member 4, and as a result, a bent portion 2a protruding in the cable circumferential direction (along the inner circumferential surface of the belt member 4) is formed in the electric wire 2. At this time, if the twisting direction of the cable core 3 is opposite to the winding direction of the tape member 4, the electric wire 2 is easily moved relative to the tape member 4, and the bent portion 2a is easily formed. In the cable core 3, the twist pitch of the plurality of wires 2 constituting the outermost layer is preferably larger than the twist pitch of the plurality of wires 2 constituting the lower layer of the outermost layer. More specifically, the strand pitch of the plurality of wires 2 constituting the outermost layer may be larger than the strand pitch of the plurality of wires 2 constituting the lower layer of the outermost layer within a range in which the difference between the strand pitch of the plurality of wires 2 constituting the outermost layer and the strand pitch of the plurality of wires 2 constituting the lower layer of the outermost layer is 35mm or more. Thereby, the bent portions 2a are easily formed in the plurality of electric wires 2 constituting the outermost layer of the cable core 3. The bent portion 2a once formed remains after the bending of the cable 1 is released.

(Bundling of Cable 1)

When the cable 1 is stored in the remaining length portion or the cable 1 is stored, as shown in fig. 3 (a) and (b), the cable 1 is wound in a spiral shape and stacked in a bundle. According to the present embodiment, since the cable 1 can be bent with a small bending radius and the bent state can be maintained, the cable 1 in which the bundled portions are bundled can be made compact. As a result, the bundled portion of the cable 1 can be accommodated in a narrow space, and the cable 1 can be compactly accommodated in a narrow wiring space, thereby facilitating transportation. In the present embodiment, if the sheath 6 has adhesion on the surface thereof, the cables 1 are easily stacked and the bundled shape is easily maintained.

(Action and Effect of the embodiment)

As described above, in the cable 1 of the present embodiment, the electric wire 2 constituting the outermost layer of the cable core 3 has the curved portion 2a that is locally curved in a convex shape. This makes it possible to realize the multicore cable 1 which is easily bent with a small bending radius and can maintain a bent state.

(Summary of embodiments)

Next, the technical ideas grasped from the above-described embodiments are described by referring to the reference numerals and the like in the embodiments. However, the reference numerals and the like in the following description are not intended to limit the constituent elements in the claims to the members and the like specifically shown in the embodiments.

[1] A cable (1) is provided with a cable core (3) formed by twisting a plurality of insulated wires (2) in a multi-layer structure, a belt member (4) spirally wound around the cable core (3), and a sheath (6) covering the periphery of the belt member (4), wherein the insulated wires (2) constituting the outermost layer of the cable core (3) have a bending portion (2 a), and the bending portion (2 a) is locally bent in a convex shape so as to protrude at least in the cable circumferential direction.

[2] The cable (1) according to [1], wherein each of the insulated wires (2) constituting the outermost layer of the cable core (3) has at least one of the bent portions (2 a) within a range of a strand pitch of the insulated wires (2) constituting the outermost layer of the cable core (3) with respect to a cable length direction.

[3] The cable (1) according to [1] or [2], wherein a height from a surface of the insulated wire (2) at a portion where the bent portion (2 a) is absent to a top of the bent portion (2 a) in the bent portion (2 a) is 0.2 times or more and 0.5 times or less of an outer diameter of the insulated wire (2).

[4] The cable (1) according to any one of [1] to [3], wherein, in an arbitrary section perpendicular to a cable length direction, 30% or more and 50% or less of the insulated wires (2) constituting the outermost layer of the cable core (3) have the bent portion (2 a).

[5] The cable (1) according to any one of [1] to [4], wherein a ratio P/PD of a layer core diameter PD of an outermost layer of the cable core (3) to a strand pitch P of the insulated wire (2) is 17 or more and 22 or less.

[6] The cable (1) according to any one of [1] to [5], wherein the twisting direction of the cable core (3) is opposite to the winding direction of the tape member (4).

[7] The cable (1) according to any one of [1] to [6], wherein the cable core (3) is constituted by a layer structure of three or more layers.

[8] A method for manufacturing a cable, comprising a step of forming a cable core (3) by twisting a plurality of insulated wires (2) in a multi-layered layer structure, a step of helically winding a tape member (4) around the cable core (3), a step of providing a sheath (6) covering the periphery of the tape member (4), and a step of forming a bent portion (2 a), wherein in the step of forming the bent portion (2 a), a cable base (1 a) after forming the sheath (6) is forcibly bent via a pulley (8) having an outer diameter equal to or smaller than the twisting pitch of the cable core (3), thereby forming a bent portion (2 a) that is locally bent in a convex shape so as to protrude at least in the cable circumferential direction in the insulated wires (2) constituting the outermost layer of the cable core (3).

(Additionally remembered)

The embodiments of the present invention have been described above, but the embodiments described above do not limit the invention according to the claims. Note that all combinations of the features described in the embodiments are not limited to the means necessary for solving the problems of the invention. The present invention can be implemented by appropriately modifying the present invention within a range not departing from the gist thereof.

Claims (8)

1. A cable is provided with:

a cable core formed by twisting a plurality of insulated wires in a multi-layered structure,

A tape member spirally wound around the cable core, and

A sheath covering the periphery of the belt member;

The insulated wire constituting the outermost layer of the cable core has a curved portion that is locally curved in a convex shape so as to protrude at least in the cable circumferential direction.

2. The cable according to claim 1, wherein the insulated wires constituting the outermost layer of the cable core each have at least one of the bent portions within a range of a strand pitch of the insulated wires constituting the outermost layer of the cable core with respect to a cable length direction.

3. The cable according to claim 1, wherein a height from a surface of the insulated wire at a portion where the bent portion is absent to a top of the bent portion in the bent portion is 0.2 times or more and 0.5 times or less of an outer diameter of the insulated wire.

4. The cable according to claim 1, wherein, in an arbitrary cross section perpendicular to a cable length direction, 30% or more and 50% or less of the insulated wires constituting an outermost layer of the cable core have the bent portion.

5. The cable according to claim 1, wherein a ratio of a layer core diameter PD of an outermost layer of the cable core to a strand pitch P of the insulated wire, i.e., P/PD, is 17 or more and 22 or less.

6. The cable according to claim 1, wherein the twisting direction of the cable core is opposite to the winding direction of the tape member.

7. The cable according to claim 1, wherein the cable core is constituted by a layer structure of three or more layers.

8. A method for manufacturing a cable includes:

a step of twisting a plurality of insulated wires in a multi-layered structure to form a cable core,

A step of spirally winding a tape member around the cable core,

A step of providing a sheath covering the periphery of the belt member, and

And a step of forming a curved portion which is partially curved in a convex shape so as to protrude at least in the cable circumferential direction in the insulated wire constituting the outermost layer of the cable core by forcibly bending the cable base body after the sheath is formed via a pulley having an outer diameter equal to or smaller than the strand pitch of the cable core.