JP2017079140A - Power cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power cable that can suppress undulation due to winding and expanding from occurring.SOLUTION: A power cable 1 includes a core wire 5 obtained by twining three wire cores 3, a pressing and winding tape 7 wound tightly in the same direction as the direction of twining of the twined wire core 5 and in a circumference of the twined wire core 5, and a sheath 9 disposed on the pressing and winding tape 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power cable used for supplying power to a mobile device.

As a conventional power cable (also referred to as a power supply wire), a cable in which an insulator is provided on a composite conductor obtained by twisting together a plurality of conductors is generally used.
By the way, the power cable used when power is supplied to the mobile device or when it is necessary to connect to the power source every time it is used is stored or transported while being wound around a cable drum, etc. Stretched to connect to. For this reason, in the power cable 501 that is repeatedly wound every time it is used, as shown in FIG. 5A, there may be a “swell” in which the appearance continuously meanders.

  “Waviness” due to the unwinding of the power cable is caused by the structure of the power cable, and is a power cable with a solid structure in which resin is embedded between two twisted cores. It is easy to express. That is, when the power cable is unrolled, stress is applied to each of the cores constituting the twisted core, and tension remains in at least one of the cores. Thereby, the wire core cannot return to the original position in the twisted wire core, and it is considered that “swell” occurs as a change in appearance in order to release the tension.

  As illustrated in FIG. 5B, the power cable 501 includes a stranded wire core 505 obtained by twisting a plurality of wire cores 503 and a sheath 507 that covers the stranded wire core 505. According to this power cable 501, the sheath 507 has a solid structure in which the space between each wire core 503 and the sheath 507 in the cable is embedded, and the interposition 506 is disposed in the space surrounded by the plurality of wire cores 503. Thus, the movement of the wire core 503 due to an external force such as “bending or twisting” is suppressed to prevent “undulation” (see, for example, Patent Document 1).

  Further, as shown in FIG. 6, a conductor portion 512 obtained by twisting a plurality of metal strands and a composite conductor portion 515 obtained by twisting a plurality of covered conductor portions 513 and the composite conductor portion 515 are covered. A power cable (power cable) 511 provided with a sliding material 519 for restraining between the insulator 517 and the insulator 517 is disclosed (see Reference 2). In the power cable 511, a buffer material 525 is applied to the center of the composite conductor portion 515, and a sliding material 519, an insulator 517, a shield layer 521, and an outer layer 523 are concentrically arranged on the composite conductor portion 515. It has been subjected.

JP 2014-216052 A JP2015-49998A

  However, in the solid-state power cable 501 shown in FIG. 5B, the wire core 503 and the sheath 507 are in contact with each other, and adhesion of talc, silicon, etc. for preventing the wire core 503 and the sheath 507 from sticking to each other is prevented. An agent (lubricant) 509 is applied. As a result, although the frictional force between the wire core 503 and the sheath 507 is reduced, the frictional force is not completely lost. Therefore, the wire core 503 that has moved due to repeated winding of the power cable 501 is caused by the frictional force with the sheath 507. There has been a problem that “undulation” occurs due to the occurrence of a state in which at least one wire core 503 is strongly pulled without returning to the position.

  Further, in the power cable 511 shown in FIG. 6, a restraining slip material 519 that is a fluororesin tape is wound around the composite conductor portion 515 in the same direction as the composite conductor portion 515. Therefore, twisting back and twisting of the twisted wire due to bending are in the same direction and friction between the insulator 517 and the composite conductor portion 515 is reduced, so that fatigue disconnection due to friction can be prevented, but “waviness” is prevented. It is not possible. Further, the restraining sliding material 519 uses a special fluororesin tape, and there is a problem that the cost increases.

  This invention is made | formed in view of the said condition, The objective is to provide the electric power cable which can suppress the "swell" by winding-up.

The above object of the present invention is achieved by the following configuration.
(1) A twisted wire core obtained by twisting a plurality of wire cores, and a presser winding tape wound in close contact with and around the twisted wire cores in the same direction as the twisted wire cores. And a sheath provided on the presser winding tape.

According to the power cable having the configuration (1), since the press core tape is applied between the twisted core and the sheath, the core does not come into direct contact with the sheath. do not need. Therefore, reduction of the frictional force between the sheath and the wire core is prevented.
Furthermore, because the presser winding tape is wound in the same direction as the twisted wire core, there is no gap between the wire cores and the presser wound tape, resulting in surface irregularities (dents between the wire cores) of the twisted wire cores. Follow the presser tape to adhere. Therefore, when the synthetic resin used as the sheath is filled in the surface irregularities of the twisted wire core, the frictional force between the sheath and the wire core increases, so the movement between the sheath and the wire core is suppressed even if it is repeatedly stretched. Thus, the “swell” of the power cable can be reduced.

(2) The power cable according to claim 1, wherein the power cable is disposed in a space surrounded by the three or more wire cores, and includes an interposer for bonding the plurality of wire cores to each other.

  According to the power cable having the configuration (2) above, the positional relationship between the plurality of wire cores is fixed by the intervention, and even when the wire cores are bent and stretched, each of the plurality of wire cores has a mutual positional relationship over a long period of time. Can be maintained. Therefore, the “swell” of the power cable can be further reduced.

  According to the power cable according to the present invention, it is possible to provide a power cable in which “swell” due to winding and stretching is suppressed.

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

(A) is the partially broken perspective view of the electric power cable which concerns on one Embodiment of this invention, (b) is II sectional view taken on the line in (a). (A) is a schematic front view and II-II sectional view for explaining the manufacturing procedure of the power cable shown in FIG. 1, and (b) is a crossing of the power cable completed by the manufacturing procedure shown in (a). FIG. (A) is a schematic front view and III-III cross-sectional view for explaining the power cable manufacturing procedure according to Reference Example 1, and (b) is a crossing of the power cable completed by the manufacturing procedure shown in (a). FIG. (A) is a schematic front view and IV-IV sectional view for explaining the manufacturing procedure of the power cable according to Reference Example 2, and (b) is a crossing of the power cable completed by the manufacturing procedure shown in (a). FIG. (A) is a front view which shows the state which the "swell" produced in the conventional power cable, (b) is a cross-sectional view of the power cable shown to (a). It is an example of sectional drawing in the conventional cable for power supplies.

Embodiments according to the present invention will be described below with reference to the drawings.
As shown in FIG. 1, a power cable 1 according to an embodiment of the present invention is a power supply wire used for power supply to a mobile device, and a twisted wire core 5 obtained by twisting a plurality of wire cores 3. A presser winding tape 7, a sheath 9, and an interposition 11. The power cable of the present invention is not limited to such a configuration, and can be applied to various types of power cables provided with a shield layer, an outer layer, and the like.

  The wire core 3 is a covered electric wire composed of a conductor made of copper or an aluminum alloy and an insulator made of rubber or polyvinyl chloride (PVC) for insulatingly covering the conductor. The power cable 1 of the present embodiment is provided with three wire cores 3 having the same length and outer diameter. Two of the three wire cores 3 are used as power supply lines, and one is used as a ground line. Of course, the power cable of the present invention is not limited to the configuration with three wire cores 3, and may have two or four or more wire cores 3.

  As shown in FIG. 1, the three wire cores 3 and the interposition 11 are twisted and twisted together in a state where the interposition 11 is disposed in a space (center gap) surrounded by the three wire cores 3. A wire core 5 is formed. The positions of the three wire cores 3 are maintained by the frictional force of the contact portion with the interposition 11 and the frictional force between the wire cores 3. As the interposition, any type of interposition that can be crushed in the central gap, such as defibrated yarn (fiber interposition in which polypropylene is made into a fiber) or paper interposition, can be used.

  The presser winding tape 7 is preferably a known plastic tape or paper tape that does not reduce the frictional force between the contact surfaces of the wire core 3 and the sheath 9, such as fluororesin. As shown in FIG. 2A, the presser winding tape 7 is wound around the twisted wire core 5 along each wire core 3 in the same direction as the twisted direction of the twisted wire core 5.

  The sheath 9 is an insulating coating made of synthetic resin such as rubber or polyvinyl chloride (PVC), for example. The sheath 9 is formed to have the same length as the wire core 3 and the interposition 11 and accommodates the twisted wire core 5 formed of the wire core 3 and the interposition 11 and having the presser winding tape 7 wound around it. . The sheath 9 is provided so that its inner surface closely overlaps the presser winding tape 7 wound around the twisted core 5. That is, the sheath 9 directly covers the presser winding tape 7.

  Since the presser winding tape 7 is applied between the twisted wire core 5 and the sheath 9, the wire core 3 does not come into direct contact with the sheath 9, so an adhesion preventing agent such as talc or silicon is not used. That is, by not using the adhesion preventive agent, it is possible to prevent the frictional force between the wire core 3 and the sheath 9 from being reduced.

An example of the manufacturing procedure of the power cable 1 described above is shown below.
First, the three wire cores 3 and the interposition 11 are twisted together to produce a twisted wire core 5.
Next, as shown in FIG. 2A, the presser tape 7 is pressed by a taping machine so as to be in the same direction as the twisting direction of the twisted wire core 5 and in close contact with the periphery of the twisted wire core 5. Wrap. At this time, the presser winding tape 7 is wound along each wire core 3 in the same direction as the twisted wire core 5, so that no gap is formed between the wire cores 3 and the presser winding tape 7. The presser winding tape 7 can be brought into close contact with the surface unevenness 5 (the recess 13 between the wire cores 3).

Next, while pulling out the twisted wire core 5 around which the presser winding tape 7 is wound from the draw hole provided in the center of the extrusion die, the twisted wire core is formed from the annular resin discharge hole provided around the draw hole. A synthetic resin such as rubber or polyvinyl chloride (PVC) serving as the sheath 9 is extruded and extruded so as to cover the periphery of the sheath 5. The stranded wire core 5 around which the presser winding tape 7 is wound can improve the external appearance at the time of sheath extrusion.
Then, by this extrusion molding, the extruded synthetic resin is densely stacked on the presser winding tape 7 wound around the twisted core 5 and directly covered. The power cable 1 is obtained through these steps.

  As described above, according to the power cable 1 of the present embodiment, since the presser winding tape 7 is applied between the twisted core 5 and the sheath 9, the core 3 is not in direct contact with the sheath 9, There is no need for an adhesion inhibitor 509 such as talc or silicon (see FIG. 5B). Therefore, reduction of the frictional force between the sheath 9 and the wire core 3 is prevented.

  Furthermore, since the presser winding tape 7 is wound along each wire core 3 in the same direction as the twisted core 5, no gap is formed between the core 3 and the presser tape 7, and the twisted core 5 The presser winding tape 7 comes into close contact with the surface irregularities (the depression 13 between the wire cores 3) (see FIG. 2A). And when the synthetic resin used as the sheath 9 is filled in the surface irregularities of the twisted core 5, the synthetic resin is surely filled in the recesses 13 between the cores 3, and a stable solid structure can be obtained. The frictional force between the sheath 9 and the wire core 3 increases.

Therefore, in the solid structure power cable 1 in which the frictional force between the sheath 9 and the wire core 3 is increased, the movement of the sheath 9 and the wire core 3 is suppressed even when the power cable 1 is repeatedly stretched to reduce “swell”. be able to.
Further, as the presser winding tape 7, since a known plastic tape, paper tape, or the like is used without using a special fluororesin tape, the cost is not increased.

  When the presser winding tape 7 is wound in the direction opposite to the twisted core 5 as in the power cable 21 according to Reference Example 1 shown in FIG. 3, the gap 23 is generated by the winding tension of the presser winding tape 7. Yes (see FIG. 3A). As shown in FIG. 3B, since the presser winding tape 7 cannot be pushed into the gap 23 even with the resin pressure during extrusion, and the synthetic resin does not fall between the wire cores 3, a stable solid structure. Can't get.

  Also, as in the case of the power cable 31 according to Reference Example 2 shown in FIG. 4, the gap 23 is formed between the wire cores 3 even when the presser tape 37 is not wound around the twisted wire cores 5 (see FIG. 4). 4 (a)). As shown in FIG. 4B, since the tension is not applied to the pressing tape 37 itself, the pressing tape 37 is pushed into the gap 23 by the resin pressure at the time of extrusion. However, since tension is not applied to the pressing tape 37, wrinkles 35 are easily generated in the pressing tape 37, and there is a possibility that the appearance of the electric wire becomes uneven, such as the convex portion 33 appearing on the outer peripheral surface of the sheath 39.

  That is, in the power cable 1 having a solid structure according to the present embodiment, the press-wrapping tape 7 is wound in the same direction as the twisting direction of the twisted cores 5 so that the stable enhancement without using the adhesion preventing agent 509 is achieved. A structure can be obtained. Accordingly, it is possible to provide the power cable 1 in which the movement of the wire core 3 is moderately suppressed even when the cable is repeatedly stretched, and “undulation” is unlikely to occur.

Here, the characteristics of the embodiment of the power cable according to the present invention described above will be briefly summarized below.
[1] A twisted wire core (5) obtained by twisting a plurality of wire cores (3);
A presser winding tape (7) wound in the same direction as the twisting direction of the twisted wire core (5) and in close contact with the periphery of the twisted wire core (5);
A sheath (9) provided on the presser winding tape (7);
A power cable (1) comprising:
[2] The above, characterized in that it is disposed in a space surrounded by three or more wire cores (3), and has an interposition (11) for bonding the plurality of wire cores (3) to each other. The power cable (1) according to [1].

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  Next, in order to confirm the effect of the present invention, the power cables shown in Example 1 and Comparative Example 1 below were produced, and the undulation resistance test was performed on the power cables of Example 1 and Comparative Example 1. Went.

Example 1
The power cable of Example 1 uses a PVC-coated electric wire having a cross-sectional area of 6.0 mm ² (outer diameter: 3.7 mm) as the wire core 3 in the power cable 1 shown in FIG. Using. Then, a paper having a thickness of 0.075 mm and a width of 40 mm is formed in the same direction as the twisting direction of the twisted wire core 5 with respect to the twisted wire core 5 formed by twisting the three wire cores 3 and the interposition 11. After the presser foot tape 7 was wound, PVC was extruded to cover the presser tape 7 and covered with a sheath 9 to produce a power cable.

(Comparative Example 1)
The power cable of Comparative Example 1 uses a PVC coated electric wire having a cross-sectional area of 6.0 mm ² (outer diameter: 3.7 mm) as the wire core 503 in the conventional power cable 501 shown in FIG. Yarn was used. And after applying the talc which is the adhesion prevention agent 509 with respect to the twisted wire core 505 which twists these three wire cores 503 and the interposition 506, PVC is covered so that the circumference | surroundings of the twisted wire core 505 may be covered. The power cable was produced by extrusion molding and covering with a sheath 507.

(Swell test)
For Example 1 and Comparative Example 1, after winding the cable drum and pulling it out from the cable drum 1000 times, the amplitude Y of the “swell” in the power cable is measured, and the outer diameter X of the power cable is measured. The ratio (swell state) of the amplitude Y of “swell” was calculated (see (a) of FIG. 5). The results of repeating this every 1000 times up to 10,000 times are shown in Table 1 below.

  As is apparent from Table 1 above, in the case of the power cable of Comparative Example 1, “swell” having an amplitude Y of about 120% with respect to the outer diameter X occurred. On the other hand, in the case of the power cable of Example 1, the occurrence of “swell” was not recognized, and it was found that “swell” can be reduced. Thus, the effect of the present invention could also be confirmed from the test results.

DESCRIPTION OF SYMBOLS 1 ... Electric power cable 3 ... Wire core 5 ... Twisted wire core 7 ... Presser winding tape 9 ... Sheath 11 ... Interposition

Claims (2)

A twisted wire core obtained by twisting a plurality of wire cores;
A presser winding tape wound in the same direction as the twisting direction of the twisted wire cores and in close contact with the periphery of the twisted wire cores;
A sheath provided on the presser wound tape;
A power cable characterized by comprising:   The power cable according to claim 1, wherein the power cable is disposed in a space surrounded by the three or more wire cores, and has an interposition for bonding the plurality of wire cores to each other.

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