JP2014176159A - Shrinking-back prevention device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shrinking-back prevention device capable of surely preventing a sheath at the cable end from being shrunk largely in the axial direction without damaging the sheath.SOLUTION: On a cable holding substrate 2 for holding a high voltage cable 110 having the outer periphery of a cable core 110b insulated and covered with a sheath 110a, a plurality of sheath contact parts 21 are provided which are composed of an electric insulation member having arc-shaped contact surfaces 21a capable of contacting with the sheath 110a of a terminal part of the high voltage cable 110. The sheath contact parts 21 are arranged opposite to each other across the axis P of the high voltage cable 110. By the plurality of sheath contact parts 21, the axis P of the high voltage cable is made possible to be at least bent in right and left directions through contact with the sheath 110a.

Description

  The present invention relates to a shrinkback prevention device capable of preventing a sheath at a cable end portion from contracting in an axial direction due to the influence of solar radiation or the like.

  In cables used for power supply, the cable core and sheath repeatedly expand and contract due to the effects of direct sunlight and temperature rise, causing a shift between the cable core and sheath at the cable end, and the sheath contracts in the axial direction. Shrinkback may occur. As shown in FIG. 14A, at the time of manufacturing the cable 110, the sheath 110a and the cable core 110b are in a predetermined positional relationship. However, when shrinkback occurs, the sheath 110a is removed as shown in FIG. The sheath 110a contracts in the direction of arrow F, and the sheath 110a is displaced in the axial direction with respect to the cable core 110b, which adversely affects the distribution line.

  2. Description of the Related Art Conventionally, a technique for preventing a sheath from shifting at a cable end is known (for example, see Patent Document 1). The cable sheath slip prevention device of Patent Literature 1 prevents sheath slippage by bending a linear body such as metal into a zigzag shape and applying pressure from the outside by a pressing portion formed on the linear body. I am doing so.

JP 2006-115668 A

  However, when the sheath 110a is greatly displaced in the axial direction with respect to the cable core 110b due to the shrink back, a defective insulation portion K is generated in the cable core 110b, and a distribution line accident is caused due to insulation breakdown of the defective insulation portion K. There is. In addition, since it is impossible to return the sheath 110a once displaced by the shrinkback to the original position, as a measure for the generated shrinkback, the cable 110 terminal is replaced or the cable 100 terminal is temporarily repaired by insulating tape processing. Need to do.

  In the sheath slip prevention device of Patent Document 1, the sheath is pressed by a linear body such as metal to prevent the sheath from contracting, so that a local load acts on the sheath and the sheath may be damaged. is there. Further, since there is only one pressing portion, the effect of preventing the sheath from contracting in the axial direction is small, and it is difficult to reliably suppress the sheath from contracting.

  Accordingly, an object of the present invention is to provide a shrinkback prevention device that can reliably prevent the sheath at the cable end from contracting greatly in the axial direction without damaging the sheath.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided an arcuate contact capable of contacting the sheath of the end portion of the cable on a cable holding substrate that holds a cable in which the outer periphery of the cable core is insulated with a sheath. A plurality of sheath contact portions made of an electrically insulating member having a surface are provided, and the sheath contact portions are arranged to face each other across the axial center of the cable, and the plurality of sheath contact portions are formed by contact with the sheath. A shrinkback preventing device characterized in that the axial center of the cable can be bent at least in the left-right direction.

  According to this invention, when the sheath of the cable terminal portion and the arcuate contact surfaces of the plurality of sheath contact portions are in contact with each other, a large frictional resistance between the sheath and the sheath contact portion can be secured. Shrinkage of the sheath in the axial direction is prevented.

  The invention according to claim 2 is the shrinkback prevention device according to claim 1, wherein the cable holding substrate and the sheath contact portion are made of porcelain.

  According to a third aspect of the present invention, in the shrinkback prevention device according to the first or second aspect, the cable is located between the opposing cylindrical sheath contact portions.

  According to a fourth aspect of the present invention, in the shrinkback prevention device according to the first or second aspect, the sheath contact portion is formed on an inner surface of a holding groove into which the end of the cable can enter by pressing. It is characterized by.

  According to the first aspect of the present invention, the plurality of sheath contact portions having the arcuate contact surface are brought into contact with the sheath at the end portion of the cable, so that the frictional resistance between the sheath and the sheath contact portion is increased. It is possible to prevent the sheath at the end portion of the cable from being greatly contracted in the axial direction. Therefore, the insulation breakdown of the cable due to the shrinkback can be surely avoided, and the distribution line accident can be prevented in advance. In addition, since the cable shaft center can be bent at least in the left-right direction by utilizing a plurality of sheath contact portions having arcuate contact surfaces, the cable can be used regardless of the skill level of the operator and without damaging the cable. Can be easily held in the apparatus.

  According to the second aspect of the present invention, since the cable holding substrate and the sheath contact portion are made of porcelain, the sheath comes into contact with a highly electrically insulating porcelain, thereby improving the insulation performance of the apparatus. it can.

  According to the third aspect of the present invention, the cable is positioned between the cylindrical sheath contact portions that are arranged to face each other at a predetermined interval in the axial direction of the cable. It becomes possible to curve in the left-right direction with a curvature.

  According to the invention described in claim 4, since the sheath contact portion is formed on the inner surface of the holding groove into which the cable terminal can enter by pressing, the cable shaft can be simply pressed against the holding groove. The heart can be bent in the left-right direction, and the work of attaching the cable to the device is further facilitated. Further, since the sheath is curved along the inner surface of the holding groove, it is possible to secure a larger contact area between the sheath and the inner surface of the holding groove, and to further enhance the effect of preventing shrinkback.

It is a front view of the shrinkback prevention apparatus concerning Embodiment 1 of this invention. It is a top view of the cable holding substrate in the shrinkback prevention apparatus of FIG. FIG. 3 is a front view of the cable holding board of FIG. 2. FIG. 3 is a side view of the cable holding board of FIG. 2. It is a top view of the support plate in the shrinkback prevention apparatus of FIG. It is a front view of the cable bracket which supports the edge part of the cable of FIG. It is a side view of the cable bracket of FIG. It is a front view which shows the modification of the sheath contact part of FIG. It is a front view which shows another modification of the sheath contact part of FIG. It is a front view which shows another modification of the sheath contact part of FIG. It is a top view of the cable holding board | substrate in the shrinkback prevention apparatus concerning Embodiment 2 of this invention. It is a front view of the cable holding substrate of FIG. It is a side view of the cable holding substrate of FIG. It is a front view which shows the shrinkback in a cable edge part.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
1 to 10 show Embodiment 1 of the present invention, and particularly show a case where the present invention is applied to a high-voltage cable in a distribution line of a power supplier. As shown in FIG. 1, a brace 101 of the distribution line 100 supports a high-voltage cable 102 extending from the distribution line side. Another end of the high voltage cable 102 is connected to another high voltage cable 110 on the distribution line side. A connecting portion between the high voltage cable 102 and the high voltage cable 110 is covered with an insulating cover 103. The high voltage cable 110 has a sheath 110a and a cable core 110b. The cable core 110b is composed of an electric wire or the like for supplying power. The sheath 110a is made of an insulating coating material for insulating and protecting the outer periphery of the cable core 110b.

  The end of the high voltage cable 110 is held by the shrinkback prevention device 1 attached to the arm metal 101 side. The shrinkback prevention device 1 includes a cable holding substrate 2, a support plate 3, and wires 4 as fixing means. The cable holding board 2 is composed of porcelain as an electrical insulating member. As shown in FIGS. 2 and 3, the cable holding substrate 2 has a rectangular planar shape. A plurality of sheath contact portions 21 having arcuate contact surfaces 21 a that can come into contact with the sheath 110 a of the terminal portion of the high-voltage cable 110 are formed on the substrate main body upper surface 2 a of the cable holding substrate 2. The plurality of sheath contact portions 21 are arranged to face each other with the axis P of the high-voltage cable 110 interposed therebetween. As shown in FIG. 2, the pair of sheath contact portions 2 facing each other with the axis P of the high-voltage cable 110 interposed therebetween are arranged at a predetermined interval in the axial direction of the high-voltage cable 110. Further, each pair of sheath contact portions 2 facing each other across the axis P of the high-voltage cable 110 is alternately predetermined in the left-right direction so that the axis P of the high-voltage cable 110 can be bent in the left-right direction. It is arrange | positioned in the state which shifted | deviated only the distance.

  The sheath contact portion 21 is formed in a cylindrical shape. One end of the sheath contact portion 21 is fixed to the substrate main body upper surface 2 a of the cable holding substrate 2. The other end of the sheath contact portion 21 is formed in a bulging portion 21b that bulges slightly outward from the diameter of the arcuate contact surface 21a. The other end 21 b of the sheath contact portion 21 has a function of preventing the high-voltage cable 110 positioned between a pair of opposed sheath contact portions 21 from being detached from the sheath contact portion 21. The substrate main body back surface 2 b of the cable holding substrate 2 is formed flat and a part thereof can be in close contact with the support plate 3. The high-voltage cable 110 extends downward from one end 2f in the longitudinal direction of the cable holding substrate 2 toward the other end 2e. A fixing groove 2 h is formed in the vicinity of one end 2 f in the longitudinal direction of the cable holding substrate 2. A wire 4 as a fixing means is inserted into the fixing groove 2h. The cable holding substrate 2 is fixed to the support plate 3 via wires 4.

  In the first embodiment, the cable holding substrate 2 includes all the portions including the plurality of sheath contact portions 21 made of porcelain, and is integrally molded. As is well known, porcelain is manufactured by kneading and molding earth or powdered minerals, unglazed, then applying glaze and further firing. The cable holding substrate 2 has high electrical insulation performance like the insulator. The sheath contact portion 21 is designed in consideration of an external force such as a stretching force that acts on the high-voltage cable 110.

  FIG. 5 shows the support plate 3. The support plate 3 is made of a metal plate and has a concave planar shape. The support plate 3 is configured such that the cable holding substrate 2 is attached to the upper surface 3a side. The support plate 3 has a first fixing hole 3b and a second fixing hole 3c. The first fixing hole 3 b is for fixing the support plate 3 to the arm metal 101 of the distribution line 100. The first fixing hole 3b is for fixing a cable bracket 5 to be described later. Bolts 5 e can be inserted into the first fixing holes 3 b and the bolt holes 5 d of the cable bracket 5. The second fixing hole 3 c is for inserting a wire 4 for fixing the cable holding substrate 2 to the support plate 3.

  6 and 7 show the cable bracket 5 that supports the end of the high-voltage cable 110. The cable bracket 5 has a lower bracket 5a and an upper bracket 5b. The lower bracket 5a is fixed to the support plate 3 via bolts 5e. The high-voltage cable 110 is supported while being clamped between the lower bracket 5a and the upper bracket 5b by tightening the clamp bolt 5c, and the movement in the horizontal direction is restricted. The end portion of the sheath 110 a located on the insulating cover 103 side in the high-voltage cable 110 has a larger diameter than other portions because of the connection relationship with the insulating cover 103.

  Below, the usage method and effect | action of the shrinkback prevention apparatus 1 which concern on Embodiment 1 are demonstrated.

  As shown in FIG. 1, in the distribution line 100, the operation | work for connecting the high voltage cable 110 to the high voltage cable 102 from the distribution line side is performed. The terminal of the high voltage cable 102 extends to the vicinity of the arm metal 101 and is connected to the high voltage cable 110 above the arm metal 101. A connecting portion between the high voltage cable 102 and the high voltage cable 110 is covered with an insulating cover 103 positioned immediately above the arm metal 101.

  When the connection between the high-voltage cable 102 and the high-voltage cable 110 is completed, the support plate 3 and the lower bracket 5a of the cable bracket 5 are attached to the arm metal 101 via bolts 5e. Next, the cable holding substrate 2 is fixed to the support plate 3 via the wires 4. As shown in FIG. 1, the wire 4 is fitted in the fixing groove 2 h of the cable holding substrate 2, and in this state, both ends of the wire 4 are inserted into the fixing holes 3 c of the support plate 3, and the back surface of the support plate 3 is inserted. The cable holding substrate 2 can be fixed to the support plate 3 by connecting both ends of the wire 4 on the side. Thereafter, as shown in FIG. 7, with the high voltage cable 110 placed on the lower bracket 5a, the upper bracket 5b is connected to the lower bracket 5a via a bolt 5b. Thereby, the horizontal movement of the high voltage cable 110 is restricted.

  When the restriction of the high voltage cable 110 by the cable bracket 5 is completed, a part of the high voltage cable 110 located immediately below the cable bracket 5 is bent in the left-right direction by the cable holding substrate 2. As shown in FIG. 2, the cable holding substrate 2 includes a plurality of sheath contact portions 21 having arcuate contact surfaces 21 a that can come into contact with the sheath 110 a at the end of the high-voltage cable 110. The high-voltage cable 110 is pushed between a pair of sheath contact portions 21 arranged to face each other across the core P. Thereby, the high voltage cable 110 is bent in the left-right direction by contact with the plurality of sheath contact portions 21. In this state, contact resistance due to contact between the sheath 110a of the high-voltage cable 110 and the sheath contact portion 21 increases, and even if a force in the direction of arrow F acts on the sheath 110a of the high-voltage cable 110, The positioned sheath 110a does not move greatly in the axial direction.

  As described above, in the shrinkback prevention device 1, the plurality of sheath contact portions 21 having the arcuate contact surface 21a and the sheath 110a at the terminal portion of the high voltage cable 110 are brought into contact with each other. A large frictional resistance with the portion 21 can be secured, and the sheath 110a at the end portion of the high-voltage cable 110 can be prevented from being greatly contracted in the axial direction. Therefore, insulation breakdown of the high-voltage cable 110 due to shrinkback can be reliably avoided, and a distribution line accident can be prevented in advance. In addition, since the shaft center P of the high-voltage cable 110 can be bent at least in the left-right direction using the plurality of sheath contact portions 21 having the arc-shaped contact surface 21a, the high-voltage cable can be used regardless of the skill level of the operator. The high voltage cable 110 can be easily held by the shrinkback prevention device 1 without damaging the 110.

  Furthermore, since the cable holding substrate 2 and the sheath contact portion 21 are made of porcelain, the sheath 110a comes into contact with a highly electrically insulating porcelain, and the insulation performance of the shrinkback prevention device 1 can be improved. Further, since the high-voltage cable 110 is positioned between the cylindrical sheath contact portions 21 that are arranged to face each other at a predetermined interval in the axial direction of the high-voltage cable 110, the high-voltage cable 110 has a predetermined curvature. It is possible to curve in the left-right direction.

  FIG. 8 shows a modification of FIG. As shown in FIG. 8, the sheath contact portion 21 'is formed in an inverted truncated cone shape. That is, the sheath contact portion 21 ′ has a small diameter on the substrate main body upper surface 2 a side of the cable holding substrate 2, and gradually increases in diameter as it goes upward from the substrate main body upper surface 2 a. Thus, by forming an inverted truncated cone shape, the upper portion of the sheath contact portion 21 ′ functions similarly to the bulging portion 21 b of FIG. 2. In FIG. 8, the high voltage cable 110 is inserted between the pair of sheath contact portions 21 ′ facing each other across the axis P of the high voltage cable 110, so that the high voltage cable 110 is circled between the opposite sheath contact portions 21 ′. It comes into contact with the arcuate contact surface 21a 'and is prevented from being easily detached from between the two sheath contact portions 21'.

  FIG. 9 shows a modification of the sheath contact portion 21 of FIG. As shown in FIG. 9, a bending plate 21 c that can contact the sheath 110 a of the high-voltage cable 110 is formed at the lower end portion of the specific sheath contact portion 21. In FIG. 9, the sheath contact portions 21 having the bending plate 21 c and the sheath contact portions 21 not having the bending plate 21 c are alternately provided along the axial direction of the high-voltage cable 110. As described above, in FIG. 9, the high-voltage cable 110 allows the axis P to bend in both the left-right direction and the up-down direction (horizontal direction) by contact with the sheath contact portion 21. The frictional resistance due to the contact between the sheath 110a and the sheath contact portion 21 can be increased.

  FIG. 10 shows a modification of the sheath contact portion 21 of FIG. 2 and 8, the cross-sectional shape of the sheath contact portion 21 is circular, but the cross-sectional shape of the sheath contact portion 21 of FIG. 10 is substantially elliptical. By making the cross-sectional cross-sectional shape of the sheath contact portion 21 substantially elliptical, it is possible to secure a larger length of contact with the sheath 110a of the high-voltage cable 110 than the circular shape, and increase the contact resistance with the sheath 110a. Can be made. Moreover, the curvature of the arc-shaped contact surface 21a can be enlarged by making a cross-sectional shape into a substantially ellipse. Therefore, the curvature of the curved portion of the high-voltage cable 110 can be increased correspondingly, and the surface pressure acting on the high-voltage cable 110 due to bending can be reduced.

(Embodiment 2)
11 to 13 show a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is only the presence or absence of the holding groove 22, and the other parts are the same as in the first embodiment. Therefore, the same reference numerals as those in the first embodiment are applied to the corresponding parts. The description of the conforming parts is omitted, and only different parts are described.

  As shown in FIGS. 11 to 13, a cable holding portion 23 made of porcelain is formed on the board main body upper surface 2 a side of the cable holding board 2. The cable holding portion 23 is formed with a holding groove 22 into which the end of the high-voltage cable 110 can enter when pressed. A plurality of sheath contact portions 22a and 22b that can bend the axis P of the high-voltage cable 110 at least in the left-right direction by contact with the sheath 110a of the terminal portion of the high-voltage cable 110 are formed on the inner surface of the holding groove 22. Has been. As shown in FIG. 11, the pair of sheath contact portions 22 a and 22 b facing each other across the axis P of the high-voltage cable 110 are arranged at a predetermined interval in the axial direction of the high-voltage cable 110. Further, the pair of sheath contact portions 22a and 22b facing each other across the axis P of the high-voltage cable 110 alternately in the left-right direction so that the axis P of the high-voltage cable 110 can be bent in the left-right direction. Arranged in a misaligned state.

  In the second embodiment configured as described above, the sheath contact portions 22a and 22b are formed on the inner surface of the holding groove 22 into which the end of the high voltage cable 110 can enter by pressing, so that the high voltage cable 110 is held. The shaft center P of the high-voltage cable 110 can be bent in the left-right direction simply by pressing toward the groove 22, and the work of attaching the high-voltage cable 110 to the shrinkback prevention device 1 is further facilitated. Further, since the sheath 110a is curved along the inner surface of the holding groove 22, it is possible to secure a larger contact area between the sheath 110a and the inner surface of the holding groove 22, and further enhance the effect of preventing shrinkback. be able to.

  The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to the above-described embodiment, and even if there is a design change or the like without departing from the gist of the present invention, It is included in this invention. For example, in the first and second embodiments, the power cable of the distribution line is targeted for prevention of shrinkback, but communication cables and other types of cables that are considered to cause dielectric breakdown due to shrinkback may be targeted. . Moreover, although the cable holding substrate 2 and the sheath contact portion 21 are made of an integrally molded porcelain, only the sheath contact portion 21 may be a porcelain and the cable holding substrate 2 may be made of an electrically insulating resin. Furthermore, although the cable holding substrate 2 is fixed to the support plate 3 with the wires 4, the cable holding substrate 2 may be fixed to the support plate 3 using bolts and nuts.

DESCRIPTION OF SYMBOLS 1 Shrink back prevention apparatus 2 Cable holding board | substrate 21 Sheath contact part 21a Arc-shaped contact surface 22 Holding groove 22a Sheath contact part 22b Sheath contact part 3 Support plate 4 Wire 5 Cable bracket 100 Power transmission tower 101 Arm metal 110 High voltage cable (cable)
110a sheath 110b cable core P axis

Claims (4)

  A cable holding substrate for holding a cable whose outer periphery is insulated with a sheath is provided with a plurality of sheath contact portions made of an electrically insulating member having an arcuate contact surface that can come into contact with the sheath at the end portion of the cable. The sheath contact portions are arranged to face each other across the cable shaft center, and the plurality of sheath contact portions can bend the cable shaft center at least in the left-right direction by contact with the sheath. A shrinkback prevention device characterized by being provided.   The shrinkback prevention device according to claim 1, wherein the cable holding substrate and the sheath contact portion are made of porcelain.   The shrinkback prevention device according to claim 1 or 2, wherein the cable is positioned between cylindrical sheath contact portions arranged to face each other at a predetermined interval in the axial direction of the cable.   The shrink-back preventing device according to claim 1, wherein the sheath contact portion is formed on an inner surface of a holding groove into which the end of the cable can enter by pressing.

Images