JP6024042B2 - Rubber unit for connecting spiral core and power cable - Google Patents

Description

  The present invention relates to a spiral core for a rubber unit or the like used for a connection portion of a power cable.

  A rubber unit is used to insulate the connection portion of the power cable. The rubber unit is configured by arranging a cold shrink tube on the outer periphery of the spiral core. The cold shrink tube is a member in which an internal semiconductive layer, an insulating layer, an external semiconductive layer, and the like are integrally formed. The inside diameter of the cold shrink tube is smaller than the outside diameter of the connected power cable.

  The spiral core (expansion holding member) holds the cold shrink tube in an expanded state. The spiral core is formed by spirally winding a spiral core string. The substantially cylindrical shape can be maintained by winding the spiral core string in a spiral shape and fitting both sides of adjacent spiral core strings together.

  The cold shrink tube is held in an expanded state by the spiral core. The inner diameter of the spiral core is larger than the outer diameter of the power cable, and the rubber unit can be moved along the power cable. After connecting the power cables and moving the rubber unit to the connection portion of the power cable, when the spiral core string is unwound, the cold shrink tube is contracted by its own elastic force and closely contacts the connection portion of the power cable. Such a rubber unit is described in Patent Document 1, for example, and a spiral core is described in Patent Document 2, for example.

JP 2001-37032 A JP 2010-094011 A

  The spiral core used as described above needs to maintain the expanded state of the cold-shrinkable tube against the shrinkage force of the cold-shrinkable tube provided on the outer periphery. Therefore, the strength required to prevent the spiral core from being crushed with respect to the force received from the cold shrink tube is required. For this reason, the fitting force more than predetermined is calculated | required also in the fitting part of spiral core strings.

  For this reason, when it becomes a spiral core of a large-sized rubber unit especially applied to ultra-high voltage cables for 275 kV, 500 kV, etc., the fitting force between the spiral core strings is very strong, and the spiral core string from the end of the spiral core It is difficult for the operator to unfasten the fitting with a finger when first unpacking. For this reason, an operator may use tools, such as pliers.

  However, when such a tool is used, there is a risk that the cold shrink tube may be slightly damaged. In an ultra high voltage cable, since the voltage and the electric field are high, the scratches generated in this way can cause dielectric breakdown.

  The present invention has been made in view of such problems, and even if the fitting force between spiral core strings is increased, the spiral core can reduce the risk of damaging the cold shrink tube when the spiral core string is unwound from the end. The purpose is to provide.

In order to achieve the above-described object, the first invention is a spiral core that is inserted into a cold shrinkable tube in order to keep the diameter expanded, and a spiral core string is provided in a spiral shape and adjacent to the spiral core. The spiral core cords are fitted into each other to form a substantially cylindrical shape, and at least one end of the spiral core cord is within a predetermined range, the release of the fit between the spiral core cords is more than other parts. An easy-to-fitting portion that is easy to form is formed, and the spiral core cords are fitted with each other in a concave-convex shape in the cross-section of the spiral core cord, Unlike said concavo-fitting force of the irregular shape of the fitting releasing easily unit rather weak than the fitting force of the uneven shape at the other sites, the fitting in a cross section perpendicular to the longitudinal direction of the spiral core cord Irregularities of the release readily portion has a shape part of the concavo-convex shape of the other portions is removed, except a part that has been removed of the disengagement facilitating portion is the said other portion and substantially the same shape It is a spiral core characterized by this.

  By doing this, it is possible to secure the fitting force of the part excluding the easy-to-release part of the spiral core, and it is possible to easily release only the end of the spiral core and unwind the spiral core string. Become. Therefore, the spiral core string can be released without using a tool or the like.

  In this way, by changing the uneven shape of the cross section of the predetermined length of the end portion of the spiral core string, it is possible to easily form the easy-to-fit release portion having a weak fitting force only at the predetermined length of the spiral core string. it can. In addition, a fitting force means the difficulty of unwinding the fitting parts which mutually fit, and a weak fitting force means that it is easy to undo.

  A tape-like member may be sandwiched between the fitting portions between the spiral core strings in the fitting release easy portion.

  Thus, by sandwiching the tape-like member, the tape-like member can be used as an auxiliary member when unwinding the spiral core string. Specifically, the spiral strings that are fitted can be released by strongly pulling the tape-shaped member in a state where the spiral core string is sandwiched between the tape-shaped members.

  A lubricant may be applied to the fitting portion between the spiral core strings in the fitting release easy portion.

  By applying the lubricant in this way, the sliding between the spiral core strings is improved, so that the spiral core strings fitted can be easily released.

The spiral core strings are engaged with each other in the concave-convex shape in the cross-section of the spiral core string, and in the easy-to-fit portion, a part of the convex portion of the concave- convex shape with respect to the longitudinal direction of the spiral core string. Alternatively, a part of the tip may be removed.

  In this way, by removing a part of the concave and convex shape in the longitudinal direction of the spiral core string, the fitting length per unit length is shortened compared with other parts in the easy-to-fitting part. Can do. Accordingly, it is easy to release the fitting.

  2nd invention uses the spiral core concerning 1st invention, the normal temperature shrinkable tube of the diameter-expanded state is provided in the outer periphery of the said spiral core, and the said fitting cancellation | release is carried out from the edge part of the said normal temperature shrinkable tube A rubber unit for connecting a power cable, wherein an easy part is exposed.

  Thus, by using the rubber unit having the spiral core having the easy-to-release part at the end, the spiral core string at the end can be easily released without using a tool or the like. Moreover, a high fitting force can be ensured in the spiral core positioned inside the cold shrink tube. Accordingly, it is possible to obtain a rubber unit that can be applied to an ultra-high-voltage power cable and has excellent power cable connection workability.

  According to the present invention, there is provided a spiral core or the like that can be operated without using a tool or the like when the spiral core string is unwound from the end portion even if the fitting force between the spiral core strings is increased. can do.

(A) is a figure which shows the spiral core 1, (b) is sectional drawing of the spiral core string 3. FIG. The figure which shows the process of fitting the spiral core string 3. FIG. It is a figure which shows the shape of the fitting part of the spiral core string 3, (a) is sectional drawing of a stationary part, (b) And (c) is a figure which shows the state which removed a part of fitting part. (A)-(b) is a figure which shows the connection process of the power cable using the rubber unit 10. FIG. The figure which shows the state which cancels | releases the fitting of the fitting part of the edge part of the spiral core string 3. FIG. (A)-(c) is a figure which shows the connection process of the power cable using the rubber unit 10. FIG. The figure which shows the state which pinched | interposed the glass tape 27 in the edge part of the spiral core string 3. FIG. The figure which shows the state which removed a part of fitting part of the spiral core string 3. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown to Fig.1 (a), the spiral core 1 is comprised by the spiral core string 3 being wound helically. The spiral core string 3 is made of resin, for example.

  As shown in FIG.1 (b), the spiral core string 3 is provided with fitting parts 9a and 9b on both sides. The fitting part 9a has the convex part 5a and the recessed part 7a. The fitting part 9b has the convex part 5b and the recessed part 7b. The convex portions 5a and 5b have thick tip portions, and the concave portions 7a and 7b have wide back portions. The shape of the concave portion 7a corresponds to the convex portion 5b, and the shape of the concave portion 7b corresponds to the convex portion 5a. The convex portions 5 a and 5 b and the concave portions 7 a and 7 b are directed in a direction A slightly inclined with respect to the radial direction X of the spiral core 1. The radial direction X of the spiral core 1 is also the thickness direction of the spiral core string 3.

  When the spiral core string 3 is rounded into a spiral shape and fitted in the direction of arrow A in FIG. 2 (a), as shown in FIG. 2 (b), a fitting portion 9a between adjacent spiral core strings 3; 9b can be fitted. That is, the convex part 5a of the spiral core string 3 on one side fits into the concave part 7b of the spiral core string 3 on the other side, and the convex part 5b of the spiral core string 3 on the other side is connected to the spiral core on one side. Fit into the recess 7 a of the string 3. Thus, the cylindrical spiral core 1 is formed by fitting the spiral core strings 3 adjacent to each other. The shape of the fitting portions 9a and 9b is not limited to the illustrated example. If the fitting is possible, the shapes of the fitting portions 9a and 9b can be appropriately designed.

  As shown in FIG. 1, a fitting release easy portion 4 is formed on at least one end of the spiral core 1 formed to have a predetermined length. The fitting release easy part 4 is formed from the end of the spiral core 1 to the spiral core string 3 having a predetermined length. For example, the easy-to-release part 4 may be formed from the end of the spiral core string 3 to a length of about 50 mm.

  FIG. 3A is a cross-sectional view of the spiral core cord 3 in a portion other than the easy-to-release part 4 (hereinafter simply referred to as “stationary part”). The maximum width B1 of the convex part 5a of the fitting part 9a is sufficiently larger than the opening width C2 of the concave part 7b of the fitting part 9b. Similarly, the maximum width B2 of the convex part 5b of the fitting part 9b is sufficiently larger than the opening width C1 of the concave part 7a of the fitting part 9a. Therefore, when the fitting portions 9a and 9b are fitted to each other as shown in FIG. 2B, the convex portions 5a and 5b are unlikely to come out of the concave portions 7a and 7b, and a high fitting force can be obtained.

  FIG. 3B is a cross-sectional view of the spiral core string 3 at the site of the easy-to-release part 4. In the fitting release easy portion 4, fitting portions 8a and 8b are formed instead of the fitting portions 9a and 9b. The fitting portions 8a and 8b are formed of convex portions 6a and 6b from which the inner portions of the convex portions 5a and 5b are removed with respect to the fitting portions 9a and 9b. That is, the maximum width E1 of the convex part 6a of the fitting part 8a is slightly larger than the opening width D2 of the concave part 7b of the fitting part 8b. Similarly, the maximum width E2 of the convex part 6b of the fitting part 8b is slightly larger than the opening width D1 of the concave part 7a of the fitting part 8a. Therefore, when the fitting portions 8a and 8b are fitted to each other, the convex portions 6a and 6b are fitted to the concave portions 7a and 7b, but when compared with the fitting portions 9a and 9b shown in FIG. The mating force is weak. For this reason, the spiral core strings 3 can be easily unfitted.

  In addition, the form of the fitting release easy part 4 is not restricted to the example shown in FIG.3 (b). For example, as shown in FIG. 3C, convex portions 6a and 6b from which a part of the tips of the convex portions 5a and 5b are removed may be used. Even in this case, the maximum width G1 of the convex portion 6a of the fitting portion 8a is slightly larger than the opening width F2 of the concave portion 7b of the fitting portion 8b, and the maximum width G2 of the convex portion 6b of the fitting portion 8b is It becomes slightly larger than the opening width F1 of the recess 7a of the fitting portion 8a. Therefore, the fitting force can be made weaker than the fitting portions 9a and 9b shown in FIG. For this reason, the spiral core strings 3 can be easily unfitted.

  Thus, by changing the cross-sectional shape (uneven shape) of the spiral core string 3 between the engagement release easy part 4 and the steady part, the fitting force between the spiral core strings 3 in the engagement release easy part 4 is It can weaken with respect to the fitting force in a stationary part. In addition, the cross-sectional shape of the fitting easy release part 4 is not restricted to the example illustrated, Other shapes may be sufficient if a fitting force can be weakened.

  Moreover, although the example which formed the fitting parts 8a and 8b in the both sides of the spiral core string 3 was shown in the fitting cancellation | release easy part 4, only any one may be sufficient. For example, in FIG. 3 (b), one fitting portion 8a may be replaced with the fitting portion 9a in FIG. 3 (a), and only the other may be the fitting portion 8b. Even if it does in this way, compared with a stationary part, a mutual fitting force can be weakened.

  Next, a method for connecting a power cable using a rubber unit having the spiral core 1 will be described with reference to FIGS. As shown in FIG. 4A, the rubber unit 10 is configured by disposing a room temperature shrinkable tube 11 in an expanded state on the outer periphery of the spiral core 1. The above-described easy-to-fit part 4 (FIG. 1) is provided at a position exposed from the normal temperature shrinkable tube 11. That is, the stationary part of the spiral core 1 is located inside the cold shrink tube 11.

  The cold shrink tube 11 has an internal semiconductive layer, an insulating layer, an external semiconductive layer, and the like, and is made of an elastic material such as silicone rubber or EP rubber. Further, the power cables 20a and 20b are composed of the conductor portion 13, the internal semiconductive layer 17, the insulating layer 19, the external semiconductive layer 21, the external insulating layer 23, and the like from the inside.

  First, as illustrated in FIG. 4A, the conductor portions 13 of the power cables 20 a and 20 b are opposed to each other and connected to the rubber unit 10 with the sleeve 15 in a state where the one power cable 20 a is inserted in advance. At this time, the rubber unit 10 is retracted to the one power cable 20a side. Since the inner diameter of the spiral core 1 is larger than the outer diameter of the power cables 20a and 20b, the rubber unit 10 can be moved along the power cables 20a and 20b.

  Next, as shown in FIG. 4B, the spiral core string 3 at the end of the rubber unit 10 on the power cable 20b side is unwound. The end of the unrolled spiral core string 3 (fitting release easy portion 4) is fixed to the outer periphery of the power cable 20a by the tape 25. In addition, the fixing method of the spiral core string 3 is not limited to the tape 25, and other fixing members such as a band may be used.

  FIG. 5 is a view showing a state in which the spiral core string 3 at the end of the spiral core 1 is unfitted. As described above, in the steady portion, the fitting portions 9a and 9b are strongly fitted to each other, so that the normal temperature shrinkable tube 11 does not collapse. On the other hand, since the easy-to-release part 4 in the part exposed from the normal temperature shrinkable tube 11 is fitted with the fitting part 8a (8b) whose fitting force is weaker than the fitting parts 9a and 9b, the operator The fitting of the fitted spiral core strings 3 can be easily released without using a tool or the like.

  Next, as shown in FIG. 6 (a), the rubber unit 10 is moved to the power cable 20b side (in the direction of arrow I in the figure), and the rubber unit 10 is disposed so as to cover the connecting portions of the power cables 20a and 20b. . At this time, since one end portion of the spiral core string 3 is fixed to the outer periphery of the power cable 20a, the fitting of the spiral core string 3 is sequentially unwound from the end portion as the rubber unit 10 moves. In addition, when the rubber unit 10 is moved, the end of the cold shrinkable tube 11 is preliminarily provided by the length of the spiral core string 3 that is unwound when the rubber unit 10 is moved so that a part of the cold shrinkable tube 11 does not shrink. The spiral core 1 is exposed from the part.

  Next, as shown in FIG. 6B, the end portion of the spiral core string 3 fixed to the outer periphery of the power cable 20a is removed, and the spiral core string 3 is pulled out (in the direction of arrow J in the figure). As a result, the spiral core 1 is unwound in order from the end on the power cable 20b side. As described above, the inner diameter of the cold shrink tube 11 is smaller than the outer diameter of the insulating layer 19 of the power cables 20a and 20b to be connected. Therefore, the cold shrinkable tube 11 is reduced in diameter at the part where the spiral core 1 is unwound.

  As shown in FIG.6 (c), the normal temperature shrinkable tube 11 can be closely_contact | adhered to the connection part of electric power cable 20a, 20b by extracting the spiral core string 3 completely. In addition, if the spiral core string 3 can be easily unwound at the tip, then the spiral core string 3 can be unwound by pulling the spiral core string 3. For this reason, even if the fitting force of the stationary part is strong, the fitting part can be unfitted without using a tool or the like.

  As described above, according to the present embodiment, since the fitting release easy portion 4 is provided at the end portion of the spiral core 1, the spiral core string 3 can be easily unwound from the end portion of the spiral core 1. . Therefore, even if the fitting force of the stationary part of the spiral core string 3 is increased, the end of the spiral core string 3 can be unwound without using a tool or the like.

  Moreover, such a fitting release easy part 4 can be easily formed by changing the uneven shape of the fitting part of the spiral core string 3 with respect to the stationary part. Therefore, the fitting portions 8a and 8b can be easily formed by removing a part of the fitting portions 9a and 9b of the spiral core string 3 corresponding to the fitting release easy portion 4 by polishing or the like.

  The easy-to-release part 4 is provided at a position exposed from the normal temperature shrinkable tube 11. Therefore, the fitting release portion 4 is not unfastened by the shrinkage force of the normal temperature shrinkable tube 11.

  Next, another embodiment will be described. The fitting release easy part 4 of the present invention can also be formed by sandwiching a glass tape 27 in the gap between the fitting parts 9a and 9b as shown in FIG. The glass tape 27 may be a tape-like member made of another material as long as it has a high tensile strength. By fitting the glass tape 27 in the easy-to-fitting portion 4 and pulling the glass tape 27, the fitting portions 9a and 9b can be unfitted. That is, by using the glass tape 27 as an auxiliary member for grasping the spiral core string 3, it is possible to easily release the fitting of the spiral core string 3 to form the easy-to-fitting portion 4.

  A hole 29 is provided in the vicinity of both ends of the glass tape 27. As indicated by an arrow K in the figure, the positions of the holes 29 of the glass tape 27 may be aligned, and for example, a rod-shaped member or the like may be inserted into the hole 29. By pulling the rod-shaped member downward, the spiral core strings 3 can be unfitted. In this case, it becomes easier to pull the glass tape 27 by the rod-shaped member.

  Thus, since the spiral core string 3 can be easily grasped by using the glass tape 27, it becomes easy to undo the fitting.

  Moreover, like the fitting release easy part 4 shown in FIG. 8, the fitting is released by forming a fitting part removing part 31 in which a part of the fitting part 9 b in the longitudinal direction of the spiral core string 3 is removed. It may be easy. By doing in this way, when fitting part 9a, 9b is fitted, the fitting length per unit length can be shortened. For this reason, the fitting force of the fitting release easy part 4 can be weakened. Therefore, it becomes easy to unwind the spiral core string 3.

  Also, the fitting release easy portion 4 may be formed by applying a lubricant to the fitting portions 9a and 9b. By applying the lubricant, the fitting portions 9a and 9b can be easily slipped, and the spiral core string 3 can be easily unfitted.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, as described above, various structures for weakening the fitting force of the fitting release easy portion 4 may be employed singly or in combination with each other.

DESCRIPTION OF SYMBOLS 1 ......... Spiral core 3 ......... Spiral core string 4 ......... Fitting release easy part 5a, 5b, 6a, 6b ......... Convex part 7a, 7b ......... Concave part 8a, 8b, 9a, 9b ... ... Fitting part 10 ... Rubber unit 11 ... Cold shrink tube 13 ... Conductor part 15 ... Sleeve 17 ... Internal semiconductive layer 19 ... Insulating layers 20a, 20b ... Power cable 21 ......... External semiconductive layer 23 ......... External insulating layer 25 ......... Tape 27 ......... Glass tape 29 ......... Hole 31 ......... Fitting portion removal portion

Claims (5)

A spiral core inserted into the cold shrink tube to keep the diameter expanded,
A spiral core string is provided in a spiral shape, and adjacent spiral core strings are fitted to each other to form a substantially cylindrical shape,
A predetermined range from at least one end of the spiral core string is formed with an easy-to-release part that makes it easier to release the fitting between the spiral core strings than the other parts.
The spiral core strings are engaged with each other in the shape of the concave and convex portions in the cross section of the spiral core string,
The fitting release easy part is different in the concavo-convex shape from other parts,
The fitting force of the concavo-convex shape of the fitting release easy part is weaker than the fitting force of the concavo-convex shape in other parts,
The concavo-convex shape of the easy-to-fit release portion in the cross section perpendicular to the longitudinal direction of the spiral core string is a shape in which a part of the concavo-convex shape in other portions is removed, and the easy-to-release release portion is removed. A spiral core having substantially the same shape as the other portions except for a part of the spiral core. Wherein the disengagement facilitating portion, the spiral core according to claim 1, characterized in that the tape-shaped material is interposed in the fitting portion between the spiral core cord. The spiral core according to claim 1 or 2 , wherein a lubricant is applied to a fitting portion between the spiral core strings in the fitting release easy portion. The spiral core strings are engaged with each other in the shape of the concave and convex portions in the cross section of the spiral core string,
The part of the inner side of the convex part of the concavo-convex shape or the part of the tip in the section perpendicular to the longitudinal direction of the spiral core string is removed in the easy-to-fitting part. The spiral core according to claim 3 . Using the spiral core according to any one of claims 1 to 4 ,
A power cable connecting rubber characterized in that a normal temperature shrinkable tube in an expanded state is provided on an outer periphery of the spiral core, and the easy-to-release part is exposed from an end of the normal temperature shrinkable tube. unit.

Images