JP2005044618A - Cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cable capable of preventing breakage of a sheath. <P>SOLUTION: The cable comprises a plurality of internal wire cores 12, a wire core pressing member 13 for pressing the internal wire cores 12, and the sheath 14 provided outside the wire core pressing member 13. The wire core pressing member 13 is so formed that the relation between a dynamic friction coefficient μ of the sheath 14 against the member contacting the surface of the sheath 14, and a static friction coefficient μ1 of the sheath 14 against a cable inner layer 18 composed of the internal wire cores 12 and the wire core pressing member 13 is μ≤μ1. The dynamic friction coefficient μ is 0.7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cable including a plurality of internal wire cores, a wire core holding member, and an outer sheath.

  4 and 5, for example, in the conventional cable indicated by reference numeral 1, two or more insulated wire cores 4 composed of conductors 2 and insulators 3 are twisted together, and intervening 5 is twisted between these gaps. And after having wound the press-wound tape 6 from above, it has a structure in which a sheath 7 made of polyvinyl chloride, polyethylene or the like is covered (see, for example, Patent Document 1).

In the above configuration, the press-winding tape 6 wound around the insulating wire core 4 and the interposition 5 prevents the twisted insulating wire core 4 and the interposition 5 from being loosened or unraveled. The press-wrapping tape 6 is a strip-shaped plastic tape or cloth tape. There are not only tapes but also string-like ones.
JP 2000-353431 A (Page 2, Fig. 5-6)

  By the way, in the above prior art, the frictional resistance between the press-wrapping tape 6 and the sheath 7 is smaller than the frictional resistance between the sheath 7 and the conduit through which the cable 1 is inserted (in other words, the sheath 7). The frictional force between the pipe and the pipe is greater than the frictional force between the press-winding tape 6 and the sheath 7). Therefore, there is a possibility that the sheath 7 may be damaged by the following mechanisms (1) to (4).

  (1) The sheath 7 and the pipe line are in close contact with each other with a strong force. (2) When a tensile force is applied for some reason, a deviation occurs between the sheath 7 and the insulating wire core 4 and the presser winding tape 6. (3) As a result, the sheath 7 is stretched and wrinkles are generated in the sheath 7 (4). If the sheath 7 extends beyond the allowable stretch value, the sheath 7 is broken.

  As a countermeasure, it is conceivable that a lubricant such as silicon is used when the cable 1 is inserted into the pipe line to reduce the frictional resistance between the sheath 7 and the pipe line. However, such a countermeasure has a problem that it takes time and labor when laying.

  This invention is made | formed in view of the situation mentioned above, and makes it a subject to provide the cable which can prevent damage to exterior coating | cover.

  The cable of the present invention according to claim 1, which has been made to solve the above-described problems, includes a plurality of internal wire cores, a wire core pressing member that presses the internal wire cores, and an exterior provided on the outside of the wire core pressing member. A friction coefficient μ between the contact partner that contacts the surface of the exterior coating and the exterior coating, and a static friction between the cable inner layer formed of the inner wire core and the wire core holding member and the outer sheath. The wire core pressing member is formed so that the relationship of the coefficient μ1 is μ ≦ μ1. According to the present invention having such a feature, the cable having the relationship of the dynamic friction coefficient μ ≦ the static friction coefficient μ1 is obtained by the wire core holding member, so that even if a tensile force acts on the cable for some reason, In the laid state, there is no deviation between the cable inner layer and the outer sheath. As a result, elongation of the exterior coating that exceeds the allowable elongation value that would cause breakage is avoided. In addition, the peelability of the exterior coating is maintained well without changing.

  According to a second aspect of the present invention, in the cable according to the first aspect, the dynamic friction coefficient μ is set to 0.7. According to the present invention having such characteristics, the dynamic friction coefficient μ generated at the time of cable laying is normally 0.7 or less. Deviation between the cable inner layer and the outer sheath can be avoided more reliably. Moreover, 0.7 also serves as a guide for selecting the material of the wire core holding member.

  A cable according to a third aspect of the present invention is the cable according to the first or second aspect, wherein the shape of the wire core pressing member is formed in a string or a band shape. According to the present invention having such a feature, since it has the same shape as a conventional press-wound tape or the like, a cable can be manufactured at low cost using an existing apparatus.

  The cable of the present invention according to claim 4 is characterized in that, in the cable according to claim 3, the winding pitch of the wire core pressing member around the internal wire core is set to 100 mm or less. According to the present invention having such a feature, since the wire core holding member is wound around the inner wire core at a winding pitch of 100 mm or less, loosening or breakage of the inner wire core can be avoided, The function of is surely demonstrated.

  The cable of the present invention according to claim 5 is the cable according to claim 1 or 2, wherein the shape of the wire core pressing member is formed in a band shape, and the inner wire core is overwrapped or vertically attached. It is characterized by doing so. According to the present invention having such a feature, since the shape and winding method of the conventional press-wound tape are the same, the cable can be manufactured at low cost using an existing apparatus.

  According to the first aspect of the present invention, there is an effect that damage to the exterior coating can be prevented. Moreover, there exists an effect that the peelability of exterior coating | cover can be maintained with favorable.

  According to the second aspect of the present invention, it is possible to prevent damage to the outer sheath more reliably by using the dynamic friction coefficient generated when laying the cable as a reference. In addition, there is an effect that it can be used as a guide for selecting the material of the wire core holding member.

  According to the third aspect of the present invention, since the wire core holding member has a string or band shape, the cable can be produced at low cost using an existing apparatus.

  According to the fourth aspect of the present invention, there is an effect that it is possible to surely prevent the looseness and the looseness of the internal core.

  According to the present invention described in claim 5, since it is a wire core pressing member having a belt-like shape that is overlapped or vertically attached, a cable can be manufactured at low cost using an existing device. There is an effect.

Hereinafter, description will be given with reference to the drawings.
FIG. 1 is an explanatory diagram showing a configuration of an embodiment of a cable according to the present invention. FIG. 2 is an explanatory diagram relating to the relationship between the dynamic friction coefficient μ and the static friction coefficient μ1.

  In FIG. 1, the cable of the present invention indicated by reference numeral 11 is a cable that is directly laid on the ground, for example, and includes a plurality of internal wire cores 12, wire core holding members 13, and an outer sheath 14. It is prepared for. Hereinafter, each component will be described.

  The internal core 12 is not particularly limited, but here, a known insulating core comprising a conductor 15 and an insulator 16 coated on the conductor 15 is used. In the drawing, two insulated wire cores twisted at a predetermined pitch are shown as internal wire cores 12. The internal core 12 which is an insulated core is manufactured by providing an insulator 16 made of polyvinyl chloride as an insulating coating on the conductor 15 using an extruder.

  The wire core holding member 13 is formed in a band shape. Moreover, the wire core holding member 13 is wound on the two internal wire cores 12 with a winding pitch of 100 mm or less on the two twisted internal wire cores 12 (and intervening not shown). Be good). Such a wire core pressing member 13 has the same function as a known pressing and winding tape. Further, the wire core holding member 13 has a function (described later) for preventing the outer sheath 14 from being displaced.

  The exterior covering 14 is a so-called sheath, and is formed using a sheath extrusion molding machine. That is, the exterior covering 14 is an exterior made of polyvinyl chloride (or made of polyethylene or the like) and is covered on the wire core holding member 13. The exterior coating 14 is the same as the conventional one (the peelability is kept good).

  In the above configuration, when the cable 11 is laid on the ground 17 (corresponding to the contact partner described in the claims) as shown in FIG. 2, the following relational expression is established.

  Assuming that the force applied between the exterior covering 14 and the ground 17, that is, the frictional force between the exterior covering 14 and the ground 17 is F, the frictional force F is expressed as F = W * μ (1) (μ: Coefficient of dynamic friction between the outer covering 14 and the ground 17). Further, when the force applied between the inner wire core 12 and the wire core holding member 13 and the outer sheath 14, that is, the frictional force between the cable inner layer 18 and the outer sheath 14 is F1, the friction force F1 is F1 = W. * Μ1 Formula (2) (μ1: coefficient of static friction between the cable inner layer 18 and the outer sheath 14)

  In the equations (1) and (2), the cable weight W is the same, and therefore the relationship between the dynamic friction coefficient μ between the outer sheath 14 and the ground 17 and the static friction coefficient μ1 between the cable inner layer 18 and the outer sheath 14. However, if μ> μ1, if the tensile force in the direction of the arrow acts, the exterior coating 14 tends to be in close contact with the ground 17, so that the exterior coating 14 is wrinkled and the exterior coating 14 is torn. . On the other hand, if μ ≦ μ1, the cable inner layer 18 and the outer sheath 14 tend to be in close contact with each other, so that there is no displacement between the cable inner layer 18 and the outer sheath 14, and as a result, the outer sheath 14 is not broken. Absent.

  The wire core holding member 13 constituting the cable 11 of the present invention is formed so as to have the above relationship using any one of vinyl, polyethylene, and rubber materials. Regarding the material, since the dynamic friction coefficient μ generated when laying the cable is usually 0.7 or less, it is necessary to make the material such that the static friction coefficient μ1 is 0.7 or more.

  As described above, the cable 11 of the present invention has an effect of preventing the exterior covering 14 from being damaged.

  Next, another embodiment of the cable according to the present invention will be described with reference to FIG. FIG. 3 is an explanatory diagram showing the configuration of another embodiment. In addition, the same code | symbol is attached | subjected to the fundamentally same member as the above-mentioned form, and the description is abbreviate | omitted.

  In FIG. 3, a cable 11 ′ includes two twisted inner wire cores 12, 12, a wire core holding member 13 ′ that presses the inner wire cores 12, 12, and an outer side of the wire core holding member 13 ′. And an exterior covering 14 provided on the exterior. Further, the cable 11 ′ is formed by the wire core pressing member 13 ′ so that the static friction coefficient μ1 is not less than the dynamic friction coefficient μ (μ1 ≧ μ).

  The wire core holding member 13 'is a string that is wound around the two internal wire cores 12 at a winding pitch of 100 mm or less, and is formed using any one of vinyl, polyethylene, and rubber materials.

  The cable 11 ′ has an effect that it is possible to prevent the outer covering 14 from being damaged, as in the above-described embodiment.

  In addition, it goes without saying that the present invention can be variously modified without departing from the spirit of the present invention.

It is a configuration explanatory view showing an embodiment of a cable according to the present invention. It is explanatory drawing which concerns on the relationship between dynamic friction coefficient (mu) and static friction coefficient (mu) 1. It is composition explanatory drawing which shows other one Embodiment of the cable by this invention. It is a structure explanatory drawing of the cable of a prior art example. It is sectional drawing of the cable of FIG.

Explanation of symbols

11, 11 'Cable 12 Internal wire core 13, 13' Wire core holding member 14 Exterior coating 15 Conductor 16 Insulator 17 Ground (contact partner)
18 Cable inner layer

Claims (5)

A plurality of internal wire cores, a wire core pressing member that presses down the internal wire cores, and an outer sheath provided outside the wire core pressing member,
The relationship of the dynamic friction coefficient μ between the contact partner in contact with the surface of the outer sheath and the outer sheath, the static friction coefficient μ1 between the inner layer of the cable and the inner sheath of the cable core, and the outer sheath is μ. The cable core pressing member is formed so as to satisfy ≦ μ1. The cable according to claim 1,
A cable characterized in that the dynamic friction coefficient μ is 0.7. The cable according to claim 1 or 2,
A cable characterized in that the shape of the wire core holding member is formed into a string or a band. The cable according to claim 3,
The cable, wherein the winding pitch of the wire core holding member around the internal wire core is 100 mm or less. The cable according to claim 1 or 2,
A cable characterized in that the shape of the wire core holding member is formed in a band shape, and the inner wire core is overlapped or vertically attached.

Images