JP2007250363A - Sleeve for electric wire with insulation coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fire-retardant sleeve for electric wires with insulation coating, capable of compression without damaging the insulation coating at the time of sleeve compression. <P>SOLUTION: Since a peripheral part of a sleeve body 3 where an electric wire is inserted is coated by insulation coating made of an insulating synthetic resin with breaking elongation from 60 to 200% at a tensile speed from 10 to 50 mm/minute in a test method of ASTM D 638, a compressive strength from 60 to 180 MPa of a test method of ASTM D 695, a fracture intensity from 40 to 80 MPa in a test method of ASTM D 638, V-2 or more in UL94, the sleeve body can be compressed without breaking the insulation coating at the time of sleeve compression, and also has fire retardancy. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulation-coated wire sleeve, and more particularly to an insulation-coated wire sleeve used when connecting ends of two wires in a butted state.

As a conventional wire sleeve with an insulating coating, for example, one described in Patent Document 1 is known. This includes a conductive sleeve main body into which electric wires are inserted from openings at both ends in the length direction, and an insulating coating that covers the outer peripheral portion of the sleeve main body. Polyacetal (POM) or the like has been used as a material for this insulating coating (insulating synthetic resin). And when connecting two wires using this insulation-coated wire sleeve, the wires are inserted through the openings at both ends of the sleeve body, and then the insulation-coated wire sleeve is compressed by a compressor. Was.
However, the mechanical properties (breaking elongation, compressive strength, etc.) of the insulating coating material in this conventional sleeve are unknown, and as a result, whether the sleeve body can be compressed without damaging the insulating coating. Was not obvious.
Japanese Patent Laid-Open No. 9-289046

In addition, the flame retardancy (flammability) of the polyacetal, which is the material of this insulating coating, is determined according to the grade of flame retardancy when the thickness of the test piece in a 20 mm vertical combustion test by the UL94 test method is 1.5 mm. Was lower than HB (the test method for each item is the same). For this reason, the insulation coating easily burns in the event of a fire or the like, and there has been a problem in the safety of the wire sleeve with insulation coating.
Therefore, as a conventional means for solving this problem of flame retardancy, flame retardant polyethylene in which 50% by weight of a predetermined amount of flame retardant (metal hydrate, etc.) is mixed with polyethylene has been developed.
However, in the case of flame retardant polyethylene, a large compressive force cannot be transmitted to the sleeve body during sleeve compression because of insufficient compression strength. As a result, it was not possible to sufficiently obtain the tensile strength required for the connection location of the two wires using the insulation-coated wire sleeve.

An object of the present invention is to provide a wire sleeve with an insulation coating that can compress the sleeve body and suppress the occurrence of breakage of the insulation coating when the sleeve is compressed.
Another object of the present invention is to provide an insulation-coated wire sleeve that does not easily burn and can improve the safety of the insulation-coated wire sleeve in the event of a fire.

  According to the first aspect of the present invention, the sleeve body having conductivity into which the electric wires are inserted from the openings at both ends in the length direction and the outer peripheral portion of the sleeve main body are in close contact with the outer peripheral side of the sleeve main body. In the insulation-coated electric wire sleeve, the insulation coating has an elongation at break of 60 to 200% and a ASTM D 695 at a tensile rate of 10 to 50 mm / min according to the test method of ASTM D 638. This is a wire sleeve with an insulation coating made of an insulating synthetic resin having a compressive strength of 60 to 180 MPa in a test method.

  According to the first aspect of the present invention, the insulating synthetic resin used as the material for the insulating coating has an elongation at break of 60 to 200% at a tensile speed of 10 to 50 mm / min according to the test method of ASTM D 638, and ASTM. Since the compression strength in the test method of D 695 has a mechanical property of 60 to 180 MPa, the sleeve body can be compressed, and damage to the insulation coating due to the compression force at the time of sleeve compression can be suppressed. .

The use of the insulation-coated wire sleeve is not limited. For example, it can be used as a wire sleeve capable of omitting the insulation treatment work at the connection point of the high-voltage insulated distribution line.
As the electric wire, for example, a general-purpose electric wire covered with a metal wire with an insulating coating, and various insulating electric wires such as an ACSR wire (distributed electric wire laid on a power pole, etc.) can be employed.
The compression force at the time of compressing the sleeve varies depending on the diameter of the sleeve for the electric wire with insulation coating, the material and the thickness of the sleeve body, and the like. For example, when an aluminum tube having a thickness of 3.3 mm is used for the sleeve body, the sleeve compression force when the diameter of the sleeve for the wire with insulation coating is 20.1 mm is 19.4 to 29.0 kgf / mm ² , Further, when the diameter of the sleeve for the electric wire with insulation coating is 26.5 mm, the sleeve compression force is 15.9 to 23.8 kgf / mm ² . Further, when a copper tube having a thickness of 5.0 mm is adopted for the sleeve body, the sleeve compression force when the diameter of the sleeve for the insulated sheathed wire is 20.0 mm is 34.37 kgf / mm ² , and the insulated sheathed wire When the sleeve diameter is 25.0 mm, the sleeve compression force is 27.81 kgf / mm ² .

As the material of the sleeve body, for example, a conductive material such as aluminum or copper can be employed.
The shape of the sleeve body is arbitrary. However, a straight body is common.
In the in-cylinder space of the sleeve body, a partition wall may be provided at an intermediate portion in the length direction of the sleeve body. Thereby, the conductor length of the left and right electric wires to be connected can be automatically equalized. The partition wall may be the same material as the sleeve body or a different material.
A conductive compound may be injected into the in-cylinder space. As the compound, for example, a paste in which metal particles are mixed into grease can be used.

As the insulating synthetic resin, for example, polyacetal, polycarbonate, polyether sulfone, rigid PVC, polyphenylene ether, or the like can be used.
If the breaking elongation of the insulating synthetic resin is less than 60%, the insulating coating cracks when the sleeve is compressed. Moreover, when it exceeds 200%, there exists a possibility that desired compression strength may not be obtained about a sleeve main body.
When the compressive strength of the insulating synthetic resin is less than 60 MPa, the metal sleeve (sleeve body) cannot be compressed. On the other hand, if it exceeds 180 MPa, the insulating coating film becomes harder and the elongation decreases, and the possibility of being brittle and cracking increases.

The thickness of the insulating coating is 2.0 to 4.0 mm. If it is less than 2.0 mm, the strength of the insulation coating is lowered and the insulation capability is also lowered. On the other hand, if it exceeds 4.0 mm, the sleeve body will be insufficiently compressed when the sleeve is compressed.
As a method of covering the sleeve main body with an insulating coating, for example, a method of integrally forming a flame retardant insulating coating on the outer peripheral wall of the sleeve main body by molding or an adhesive can be employed.
A known compressor can be used for compression of the sleeve body. For example, it is possible to employ one that employs oil pressure as a driving source or one that employs electric power.
When compressing the sleeve, the sleeve may be continuously compressed from an intermediate portion in the length direction of the sleeve body toward both ends thereof, or may be compressed intermittently.

  The invention according to claim 2 is the wire sleeve with insulation coating according to claim 1, wherein the insulating synthetic resin has a breaking strength of 40 to 80 MPa according to a test method of ASTM D638.

  According to the second aspect of the present invention, since the insulating synthetic resin having the mechanical property of 40 to 80 MPa in breaking strength according to the test method of ASTM D 638 is adopted as the material for the insulating coating, Breakage of the insulation coating due to the compressive force can be suppressed.

  If the breaking strength of the insulating synthetic resin is less than 40 MPa, the desired compressive strength may not be obtained for the sleeve body. If it exceeds 80 MPa, the insulating coating tends to break.

  The invention described in claim 3 is the wire sleeve with insulation coating according to claim 1 or 2, wherein the insulating synthetic resin is polyacetal, polycarbonate, or polyethersulfone.

  According to a fourth aspect of the present invention, the insulating synthetic resin has a flame retardance rating of V-2 or higher in the UL94 test method. This is a wire sleeve with an insulation coating.

  According to the fourth aspect of the present invention, since the thermal property of UL94, which is a flame retardancy test method, is employed as the insulation coating, the flame retardance grade is V-2 or higher. It is difficult to burn, and the safety of the insulated sheath for electric wire in the event of a fire can be improved. The flame retardancy test of UL94 is, for example, holding a 20 mm long test piece vertically, indirect flame for 10 seconds at the lower end of the test piece, and if it stops within 30 seconds, it will be indirect for another 10 seconds Flame. The degree of flame retardancy of the test piece at this time is examined.

Flame retardancy refers to a state (property) in which the ignitability and flame spreadability are inferior to those when a combustible substance is ignited or spread.
The flame retardance grade of V-2 or higher includes not only the V-2 grade but also those of the V-1 grade, V-0 grade, 5VA grade, and 5VB grade, which have higher flame retardancy.
When the flame retardancy grade of the insulating synthetic resin is less than V-2, there is a risk of burning. A preferable grade of the flame retardancy of the insulating synthetic resin is V-1.
In the UL94 test method, as the insulating synthetic resin having a flame retardancy grade of V-2 or higher, for example, flame retardant polycarbonate can be employed.

  According to the first aspect of the present invention, the insulating synthetic resin used as the material for the insulating coating has an elongation at break of 60 to 200% at a tensile speed of 10 to 50 mm / min according to the test method of ASTM D 638, and ASTM. Since a material having a mechanical property of a compressive strength of 60 to 180 MPa in the test method of D695 is employed, damage to the insulating coating due to the compressive force during sleeve compression can be suppressed.

  In particular, according to the invention described in claim 2, since the insulating synthetic resin having the mechanical property of 40 to 80 MPa in breaking strength according to the test method of ASTM D 638 is adopted as the material of the insulating coating, the sleeve compression It is possible to suppress breakage of the insulation coating due to the compressive force at the time.

  Further, according to the invention of claim 4, since the insulating coating employs a thermal property of UL94, which is a flame retardancy test method, a flame retardance grade of V-2 or higher. The sleeve is difficult to burn, and the safety of the sleeve for an insulated wire in a fire can be improved.

  Examples of the present invention will be specifically described below.

  In FIG. 1, reference numeral 10 denotes an insulation-coated wire sleeve according to Embodiment 1 of the present invention. The insulation-coated wire sleeve 10 has wires (connected insulated wires) from openings at both ends in the length direction. A sleeve body 3 in which the compound 2 is inserted into a part of the cylinder space to be inserted and the partition wall 1 is provided in the middle portion in the longitudinal direction of the cylinder space, and each base part corresponds to the sleeve body 3. A pair of cylindrical waterproof rubber members 6 coupled to each other in a fixed state in the opening, an insulating coating 7 that covers the outer periphery of the sleeve body 3 in close contact with the outer periphery of the sleeve body 3, 7 and a pair of caps 9 that fix both waterproof rubber members 6 to both openings of the sleeve body 3.

Both electric wires are obtained by coating a metal wire with an insulating coating of polyolefin resin.
The sleeve body 3 is a straight body pipe (straight pipe) made of aluminum (1100-H14 defined in JIS H4080) having a diameter of 13.9 mm and a thickness of 3.3 mm. The diameter of the sleeve 10 for electric wire with insulation coating is 20.1 mm. The in-cylinder space of the sleeve main body 3 is divided into two on the left and right sides by a partition wall 1 made of the same material as the sleeve main body 3. The compound 2 is injected into the central portion of the in-cylinder space, that is, the back side portion of the two divided spaces. Compound 2 employs a mineral oil-based grease as a main component, which is mixed with metal particles, a friction force enhancer, and other inorganic substances.

The insulating coating 7 is made of, for example, an insulating synthetic resin in Table 1 described later such as flame retardant polycarbonate. The insulating coating 7 is molded over the entire area of the outer peripheral side of the sleeve body 3 and the outer peripheral side of the waterproof rubber member 6 and the both end surfaces thereof are substantially aligned with the tip end surface of the corresponding waterproof rubber member 6. Yes. As a result, the sleeve body 3 and the two waterproof rubber members 6 are firmly integrated (connected) by the insulating coating 7. The thickness of the insulating coating 7 is about 3.1 mm. On the outer peripheral side of the insulating coating 7, a plurality of protrusions b extending in the circumferential direction with a constant pitch in the length direction and having a height of about 1 mm are formed. Each protrusion b determines a compression position of a compression tool of a hydraulic cylinder type that compresses the insulating coating 7 and the sleeve body 3.
The insulating synthetic resin used as the material for the insulating coating is an elongation at break of 60 to 200% at a tensile speed of 10 to 50 mm / min in the test method of ASTM D 638, and compression by the test method of ASTM D 695. It has a mechanical property of a strength of 60 to 180 MPa and a breaking strength of 40 to 80 MPa according to the test method of ASTM D 638, and its thermal property is a flame retardancy rating of V94 in the flame retardancy test UL94. Use -2 or higher.

As shown in FIGS. 2 and 3, both waterproof rubber members 6 are cylindrical bodies made of ethylene propylene rubber, and prevent water and the like from entering the cylinder space of the sleeve body 3 from the outside, and are inserted into the cylinder space. It is a member which prevents the outflow of the compound 2 made outside.
A plurality of (for example, four or five) annular projections 5 are arranged on the inner peripheral wall of the through hole 4 which is the inner path of the both waterproof rubber members 6 in a parallel state in which the thickness directions are aligned with the axial direction of the through hole 4. It is arranged. Each annular protrusion 5 has an inner diameter that comes into contact with the outer peripheral surface of the electric wire inserted into the in-cylinder space.
Of the inner peripheral walls of the through holes 4 of both waterproof rubber members 6, a closing film 6 a that can be pierced by pressure when the electric wire is pushed into the through holes 4 is disposed at the end of the sleeve body 3 side. Both blocking films 6a are the same material as the waterproof rubber member 6 and are integrally formed with a thickness of 0.3 mm.

Both caps 9 are polyethylene cylindrical bodies (rigid bodies). The base portions of both caps 9 are screwed into the corresponding tip portions of the insulating coating 7 (adhesion with an adhesive may be used). As a result, the waterproof rubber members 6 are firmly fixed (connected) in the respective openings of the sleeve body 3 by the corresponding caps 9. Both caps 9 are respectively provided with funnel-shaped insertion holes 8 that communicate with the through-holes 4 with the narrow-diameter side facing.
At both ends of the insulating coating 7, external screws are formed which are screwed into internal screws disposed on the inner peripheral side of the base portion of the corresponding cap 9 (the portion on the small diameter side of the insertion hole 8). Yes. Further, between the inner peripheral wall of both the insertion holes 8 and the outer peripheral wall of the cap 9, an annular shape gradually tapering toward the distal end portion of the corresponding cap 9 (the end portion on the diameter increasing side of the insertion hole 8). A gap 8b is formed. Note that the gap 8b is not necessarily formed (FIG. 1).

Next, a method of using the insulating coated wire sleeve 10 according to the first embodiment of the present invention will be described.
As shown in FIGS. 1 to 3, the blocking films 6 a of both waterproof rubber members 6 are in a state where the respective blocking films 6 a are pressed against the corresponding end surfaces of the sleeve body 3 in advance at the openings at both ends of the insulating coating 7. A pair of waterproof rubber members 6 are attached to each other with a slight gap between the opposite end face and the corresponding opening end face of the insulating coating 7. At this time, each waterproof rubber member 6 is inserted with its bottom facing the back of the insulating coating. Then, both caps 9 are screwed to both ends of the insulating coating 7. Thereby, the former side of the inner peripheral wall of both insertion holes 8 faces the front end side of the corresponding waterproof rubber member 6. Therefore, both waterproof rubber members 6 are connected to both ends of the insulating coating 7 so as not to be detached.

Next, the insulation coatings at the ends of the two wires are peeled off, and the exposed ends of both wires are pushed into the through holes 4 of the waterproof rubber member 6 from the corresponding insertion holes 8 of the cap 9. At this time, the blocking film 6a is pierced by the pressing force of the electric wire (conductor). Thereafter, by continuing these pushing operations, the leading ends of the two wires reach the intermediate portion in the longitudinal direction of the in-cylinder space of the sleeve body 3. The occlusion film 6a can prevent leakage of the compound 2 from the inside of the sleeve body 3 and storage of rainwater and the like into the sleeve body 3 when the sleeve is stored and when the sleeve is conveyed. When both the conductors reach the partition wall 1 of the sleeve main body 3, the insulating coatings at the tips of the two electric wires are arranged in the through holes 4 of the waterproof rubber member 6.
Thereafter, using a compression tool, the sleeve body 3 is compressed from above the flame-retardant insulating coating 7 by a compressor with a width of 19.3 mm and a compression force of 12 t. When compression at one location is complete, compression is performed such that the next location is compressed. The direction of compression may be the direction from the central portion in the length direction of the sleeve body 3 toward the end portion, or may be the opposite direction.

Hereinafter, the difference in mechanical properties and flame retardancy of the insulating synthetic resin that is the material of the insulating coating 7 will be described by comparing the present invention with the conventional product.
(1) Materials used The insulating synthetic resins used in Test Examples 1 to 3 and Comparative Examples 1 to 3 are shown below.
Test Example 1 is a flame retardant polycarbonate (trade name SD Polycarbonate 87-20 manufactured by Sumitomo Dow).
Test Example 2 is polyethersulfone (trade name Ultra Zone E2010 manufactured by BASF).
Test Example 3 is polyvinyl chloride (trade name KVC943NBA manufactured by Showa Kasei Kogyo Co., Ltd.).

Comparative Example 1 is polyetherimide (trade name ULTEM 1000 manufactured by GE Plastics).
Comparative Example 2 is polyethylene (trade name HI-ZEX 2100J manufactured by Sumitomo Mitsui Polyolefin Co., Ltd.).
Comparative Example 3 is EPDM (in-house blended ethylene propylene diene monomer; ethylene propylene diene terpolymer).

(2) Molding of sample for evaluation The pellet was molded into a plate-like product by a hot press machine in which the temperature of the press member was adjusted above the melting point of each material, and these were used as samples for evaluation.

(3) Evaluation item and evaluation method a) Evaluation of elongation at break The elongation at break at a tensile rate of 10 to 50 mm / min was measured according to the elongation at break test according to the test method of ASTM D638. Specifically, a break elongation inspection device “Autograph AG-5000E” manufactured by Shimadzu Corporation was used.
b) Evaluation of compressive strength A compressive strength test according to the test method of ASTM D 695 was adopted. Specifically, “Autograph AG-5000E” manufactured by Shimadzu Corporation was used.

c) Evaluation of breaking strength A breaking strength test according to the test method of ASTM D 638 was adopted. Specifically, “Autograph AG-5000E” manufactured by Shimadzu Corporation was used.
d) Evaluation of damage to insulation coating during sleeve compression Using a compressor “SR-12L” manufactured by Sanwa Tecchi Co., Ltd. ) Sequentially compressed at 19.3 mm and a compression force of 12000 kgf.
The evaluation of the breakage of the insulating coating was made visually by an inspector.

e) Evaluation of UL-94 The flame resistance test method of UL94 was adopted. Specifically, a flame retardant inspection device “cable combustion tester” manufactured by Toyo Seiki Seisakusho was used. The grade of flame retardancy was classified into 5 levels of 5VA, 5VB, V-0, V-1, V-2 and HB in descending order of flame retardancy according to UL94.
f) Evaluation of burrs Evaluation of burrs on the insulation coating was made visually by an inspector.
g) Evaluation of flame retardancy In the flame retardancy test of UL94, the flame retardancy grade is V-2 or higher (5VA, 5VB, V-0, V-2), and less than V-2 (HB) is not acceptable. Passed.

  As is clear from Table 1, in Test Examples 1 to 3, the elongation at break was 60 to 200%, the compressive strength was 60 to 180 MPa, the break strength was 40 to 80 MPa, and the flame retardancy was UL94 (test piece thickness 1.5 mm In the vertical combustion test), it was V-2 or more, so that it was possible to suppress the occurrence of breakage of the insulation coating during sleeve compression, good sleeve compression, and good flame retardancy. On the other hand, in Comparative Examples 1 to 3, since at least one of the breaking elongation and compressive strength is less than 60% breaking elongation and less than 60 MPa compressive strength, the insulation coating is broken during compression of the sleeve and the compression is insufficient. It was not possible to suppress it. Further, Comparative Examples 1 to 3 had problems in breaking strength and flame retardancy.

It is a longitudinal cross-sectional view of the sleeve for electric wires with insulation coating which concerns on Example 1 of this invention. It is a front view of the sleeve for electric wires with an insulation covering concerning Example 1 of this invention. It is a principal part expanded longitudinal cross-sectional view of the sleeve for electric wires with an insulation coating concerning Example 1 of this invention.

Explanation of symbols

3 Sleeve body,
7 Insulation coating,
10 Insulated sheathed wire sleeve.

Claims (4)

A sleeve body having conductivity into which electric wires are respectively inserted from openings at both ends in the length direction;
In the sleeve for an electric wire with an insulation coating provided with an insulating coating that covers the outer peripheral portion of the sleeve main body in an intimate contact state on the outer peripheral side of the sleeve main body,
The insulating coating is made of an insulating synthetic resin having an elongation at break of 60 to 200% at a tensile speed of 10 to 50 mm / min according to the test method of ASTM D 638 and a compressive strength of 60 to 180 MPa according to the test method of ASTM D 695. Insulated sheathed wire sleeve.   The insulating sheathed electric wire sleeve according to claim 1, wherein the insulating synthetic resin has a breaking strength of 40 to 80 MPa according to a test method of ASTM D638.   The insulating sheathed electric wire sleeve according to claim 1, wherein the insulating synthetic resin is polyacetal, polycarbonate, or polyethersulfone.   The said insulation synthetic resin is a flame | retardant flame rating in the test method of UL94 which is V-2 or more, The sleeve for electric wires with an insulation coating of any one of Claims 1-3.

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