JP2007110847A - Structure of cable terminal connecting portion of compact power cable and cable adaptor therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate constraints on the direction of a cable core of a fan-shaped cross-section in performing terminal connection processing for a compact power cable constituted of a plurality of fan-shaped cable cores using a pre-molded insulator. <P>SOLUTION: This cable terminal connecting portion of a compact power cable is configured by twisting and sheathing a plurality of cable cores having fan-shaped cross-sections which are formed in sequence with an inner semiconductive layer 2, a cable insulator layer 3 and an outer semiconductive layer formed around the outer circumference of a fan-shaped cross-sectional conductor 1. Then, the cable insulator layer 3 of the cable core is fitted into a cable insertion hole 13 of a cable adaptor 11 which is a cylindrical gum insulator with the fan-shaped cable insertion hole 13 and a circular contour, and a portion of the cable adaptor 11 is fitted into a circular hole 14 of the pre-molded insulator 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact connection structure for a power cable having a structure in which a plurality of fan-shaped cable cores are twisted together, and a cable adapter used therefor.

  As shown in FIG. 9, a plurality of fan-shaped cable cores 5 in which an inner semiconductive layer 2, a cable insulator layer 3, and an outer semiconductive layer 4 are formed in order on the outer periphery of a conductor 1 having a fan-shaped cross section are twisted together. The power cable 8 having a structure with the sheath 7 is called a compact power cable 8 and is mainly used for wiring of equipment, vehicles, ships, and the like (see Patent Document 1). As shown in the figure, a shielding layer 6 is usually provided on the outer periphery of the cable core 5.

A processing method using a pre-molded insulator is widely used for processing a terminal connection portion of a normal power cable having a circular cross-sectional shape of the cable core. However, in the case of a compact power cable, the cross-section of the cable core 5 is used. Since the shape is a fan shape, even if a pre-molded insulator for a circular cable having a circular cable insertion hole is used as a terminal member for a terminal connection portion, it cannot be used as it is.
Therefore, it is conceivable to make the cable insertion hole of the pre-molded insulator into a fan-shaped cross section that matches the fan-shaped cable core, that is, to have a similar shape smaller than the cross-sectional shape of the cable insulating layer 3 of the cable core 5. .

Further, a normal pre-molded insulator having a circular cross-section cable core connected to the end of the fan-shaped cross-section cable core 5 and having a circular cable insertion hole at the end of the circular cross-section cable core (cable insulator layer). It is proposed that the terminal connection part is processed by mounting (Patent Document 2).
JP-A-11-329100 JP-A-6-311621

The conventional method of making the cable insertion hole of the pre-molded insulator into a fan-shaped cross section has the following problems.
The orientation of the pre-molded insulation is determined by the orientation of the cable core with the fan-shaped cross section, and the pre-molded insulation cannot be attached in any direction. The core is twisted, and stress may be applied to each part, which may affect the electrical characteristics.
In addition, there is a problem that the interfacial pressure distribution between the pre-molded insulator and the cable core (cable insulator layer) becomes uneven in the circumferential direction, resulting in unstable electrical characteristics. Specifically speaking, the surface pressure distribution is uneven. The surface pressure near the center of the fan-shaped straight portion or the fan-shaped arc is small, and the surface pressure at the fan-shaped corner is large.

  Also, as in Patent Document 2, the method of connecting a circular cross-section cable core to a fan-shaped cross-section cable has a problem that the number of parts for terminal connection increases and the work of terminal connection processing becomes complicated.

  The present invention has been made to eliminate the above-mentioned conventional drawbacks, and when performing a termination connection process of a compact power cable composed of a plurality of cable cores having a fan-shaped cross section using a pre-molded insulator, Termination connection structure for a compact power cable that eliminates restrictions on the orientation of the cable core and that does not cause uneven interfacial pressure between the pre-molded insulation and the cable insulation layer of the cable core, and the same It aims at providing the cable adapter used for.

The present invention for solving the above-described problems is obtained by twisting a plurality of fan-shaped cable cores in which an inner semiconductive layer, a cable insulator layer, and an outer semiconductive layer are sequentially formed on the outer periphery of a conductor having a fan-shaped cross section. A compact power cable termination connection structure,
A cable insulation layer of the cable core is fitted into the cable insertion hole of the cable adapter, which is a cylindrical rubber insulator having a fan-shaped cable shape and a circular outer shape, and the cable adapter portion is circular with a pre-molded insulator. It is characterized by being fitted into the hole.

A second aspect of the present invention is a cable adapter used in the terminal connection structure of the compact power cable according to the first aspect,
The cable insertion hole is similar to the cross-sectional shape of the cable insulation layer, and the cable insertion hole and the cable are in a region where the interface pressure is reduced when the cable insulation layer is fitted as a smaller fan-shaped (similar fan-shaped) cross section. The cross-sectional shape further increases the difference in fitting diameter with the insulator layer.

  According to a third aspect of the present invention, a region where the difference in fitting diameter in the cable insertion hole of the cable adapter according to the second aspect is further increased is a fan-shaped straight portion.

According to a fourth aspect of the present invention, in the cable adapter according to the third aspect of the present invention, the difference in the fitting diameter of the fan-shaped linear portion is increased by providing an inward convex radius R ₁ in the fan-shaped linear portion.

  According to a fifth aspect of the present invention, in the cable adapter according to the second aspect of the present invention, the region for further increasing the fitting diameter difference in the cable insertion hole is near the center of the fan-shaped arc.

Claim 6 is the cable adapter of claim 5, the radius R ₂ of the fan-shaped arc of the cable insertion hole is larger than the radius R _{2 'of} similar sector-shaped arc, and, similar sector the center position of the radius R ₂ The fitting diameter difference in the vicinity of the center of the fan-shaped arc is increased by lowering from the center position of the arc R ₂ ′.

Claim 7 is the cable adapter of claim 2-6, the radius R ₃ of the sector angle portion is a region where the interface surface pressure is greater larger than radius R _{3 'of} the sector angle of the similar sector, and the characterized in that the center position of the radius R ₃ is shifted inward from the central position of the radius R _{3 'of} the sector angle of the similar sector.

According to the present invention, when a terminal connection process of a compact power cable is performed using a pre-molded insulator, a cable adapter that is a cylindrical rubber insulator having a cable insertion hole and a circular outer shape is used. Therefore, a normal pre-molded insulator for a circular cable can be used. Therefore, there is no restriction on the direction of the fan-shaped cable core, and the premolded insulator can be mounted in any direction according to the device to which the cable is connected.
Further, it is not necessary to twist the cable core on which the pre-molded insulator is mounted so that the pre-molded insulator is directed toward the device, so that the cable end processing length can be shortened.

As in claim 2, when the cable insulation layer is fitted as a smaller fan-shaped cross-section similar to the cross-sectional shape of the cable insulation layer, and the fitting diameter difference is further increased for the region where the interface pressure is reduced, The interface surface pressure between the cable insulator layer and the cable insertion hole is made uniform. Thereby, electrical characteristics are improved.
Further, since the interface pressure is made uniform, the basic fitting diameter difference (fitting diameter difference with respect to the similar fan shape) can be suppressed as small as possible. That is, it is not necessary to excessively increase the basic fitting diameter difference in order not to generate a portion having a required surface pressure or less. Since the work to insert the cable insulator layer into the cable adapter is easier as the fitting diameter difference is smaller, the workability can be improved by minimizing the basic fitting diameter difference as described above. be able to.
Since the electrical characteristics are improved, the insulation thickness and the creepage length of the insulation part of the premolded insulator can be shortened, and the terminal connection part can be reduced in size.
Also, as described above, the cable end treatment length can be shortened, the insulation thickness of the pre-mold insulator and the creepage length of the insulation portion can be shortened, and the workability is improved, so that the terminal connection portion can be reduced. Cost can be reduced.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS A compact power cable terminal connection structure and a cable adapter used therefor according to the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a terminal connection structure 10 for a compact power cable according to an embodiment of the present invention.
The compact power cable targeted in this embodiment is the above-described compact power cable 8 of FIG. 9 (a), in which the inner semiconductive layer 2, the cable insulator layer 3, the outer periphery of the conductor 1 having a fan-shaped cross section are provided. In this structure, a plurality of fan-shaped cable cores 5 each having a semiconductive layer 4 formed in sequence are twisted and a sheath 7 is applied. Reference numeral 6 denotes a shielding layer provided on the outer periphery of the cable core 5. As shown in FIG. 1, a battledore terminal 9 is compression-connected to the tip of the conductor 1.

  The compact power cable terminal connection structure 10 uses a cable adapter 11 and a pre-molded insulator 12.

  The pre-mold insulator 12 is a normal pre-mold insulator for a circular cable used as a terminal member in a device direct connection type terminal connection portion, and a cable-side insulating cylinder portion 15 into which an end portion of the cable core 5 is inserted, and this And a device-side insulating cylinder 16 on the device side perpendicular to the T-shaped insulating material hollow body, and an inner semiconductive layer 19 inside an insulator 18 made of EP rubber (ethylene propylene rubber), etc. The outer semiconductive layer 20 is integrally molded on the outside, and the inside of the cable side insulating cylinder portion 15 is a circular hole 14. A cap 22 is attached to the opening on the left side of the device-side insulating cylinder portion 16, and the device-side terminal (not shown) inserted from the right side and the battledore terminal 9 are electrically connected.

Details of the cable adapter 11 are shown in FIGS. 2 (a) is an AA enlarged sectional view of FIG. 1, FIG. 4 (a) is an enlarged view showing only the cable adapter in FIG. 1, and FIG. 4 (b) is a view of FIG. 4 (c) is a cross-sectional view taken along the line BB of (a), FIG. 5 (a) is a cross-sectional view taken along the line CC of FIG. 4 (a), and FIG. 5 (b) is a view of (a) viewed from below. .
As shown in these drawings, the cable adapter 11 is a cylindrical rubber insulator having a cable insertion hole 13 in a fan shape and a circular outer shape. As shown in FIGS. 13, the cable insulator layer 3 of the cable core 5 is fitted, and the cable adapter 11 portion is fitted into the circular hole 14 of the premolded insulator 12. In this cable adapter 11, the portion that fits the cable insulator layer 3 is the insulator 11a, but the portion that covers the outer semiconductive layer 4 and the shielding layer 6 is the semiconductive layer 11b.
The pre-molded insulator 12 and the cable adapter 11 can use EP (ethylene propylene) rubber, silicon rubber, or the like.

The shape of the cable insertion hole 13 of the cable adapter 11 will be described in detail.
FIG. 2 (b) is shown for comparison with FIG. 2 (b), which is an embodiment of the present invention, and the shape of the cable insertion hole 13 ′ of the cable adapter 11 ′ is the sector cross-sectional shape of the cable insulator layer 3. FIG. 3B is an enlarged view of the shape of the cable insertion hole 13 ′. That is, the cable insertion hole 13 ′ is tightly connected to the fan-shaped cross-sectional shape of the cable insulator layer 3 with an interface pressure sufficient for calculation when the cable insulator layer 3 is fitted into the cable insertion hole 13 ′. It is a similar shape that is small enough to fit (this similar shape is called a similar sector shape). A dimensional difference in the radial direction between the cross-sectional shape of the cable insertion hole and the cross-sectional shape of the cable insulator layer 3 is referred to as a fitting diameter difference.
The cable insertion hole 13 of the cable adapter 11 of the above embodiment has a small interface pressure when the cable insulator layer 3 is fitted to the cable insertion hole 13 with respect to the similar fan-shaped cable insertion hole 13 ′. This region has a cross-sectional shape with a larger fitting diameter difference.
Specifically, as shown in FIG. 3 (a), that the fan-shaped linear portion (a point and between the point b) 13a 'of the shape with a radius R ₁ of the convex inner side (indicated by 13a) Thus, the fitting diameter difference between the cable insertion hole 13 and the cable insulator layer 3 is increased for the fan-shaped straight portion. When the fitting diameter difference with respect to the similar fan-shaped cable insertion hole 13 ′ is 1.0 mm, the portion 13 a that increases the fitting diameter difference gradually changes the fitting diameter difference from 1.0 mm to, for example, 1.5 mm. . In FIG. 3 (a), the broken line indicates the fan-shaped straight portion 13a 'of the similar fan-shaped cable insertion hole 13'. The center of the outer shape of the cable adapter 11 that is circular is indicated by O.

As described above, the difference in the fitting diameter between the cable insertion hole 13 and the cable insulator layer 3 is a region where the interface pressure is reduced when the cable insulator layer 3 is fitted into the similar fan-shaped cable insertion hole 13 ′. In the following, the fact that the interface pressure is made uniform when partially increased will be described.
FIG. 8 (a) shows the interfacial pressure distribution when the cable insertion hole of the cable adapter has a similar shape to the cable insulator layer 3 of the cable core 5 (in the case of the cable insertion hole 13 ′). It is a graph of the interfacial pressure (interface surface pressure) from the data analyzed using the data (showing the surface pressure of a half circumference counterclockwise (A → B → C) from the main part of the fan shape) .
According to this analysis, when the shape of the cable insertion hole is a similar sector (cable insertion hole 13 ′), the ratio max / min between the maximum value and the minimum value of the interface pressure on the circumference is 2.1 times and the variation is large. .

8 (b) shows a finite interface surface pressure distribution when the cable insertion hole has a cross-sectional shape as shown in FIG. 3 (a) and the fitting diameter difference is partially increased (in the case of the cable insertion hole 13). It is a graph of interface pressure (interface surface pressure) from data analyzed using the element method.
According to this analysis, when the difference in the fitting diameter is partially increased (cable insertion hole 13), the ratio max / min between the maximum value and the minimum value on the circumference is equalized 1.3 times.

In the above-mentioned compact power cable terminal connection structure 10, the cable adapter 11, which is a cylindrical rubber insulator having a fan-shaped cable insertion hole 13 and a circular outer shape, is used. An insulator 12 can be used. Therefore, there is no restriction on the orientation of the fan-shaped cable core 5, and the pre-molded insulator 12 can be mounted in any direction according to the device to which the cable is connected.
Further, it is not necessary to twist the cable core 11 to which the pre-mold insulator 12 is attached and to direct the pre-mold insulator 12 toward the device, thereby shortening the cable end processing length.
Further, when the cable insulator layer 13 is fitted as a smaller fan-shaped cross-section similar to the cross-sectional shape of the cable insulator layer 3, the fitting diameter difference is set for a region (fan-shaped linear portion 13a ′) in which the interface pressure is reduced. By making it larger, the interface pressure between the cable insertion hole 13 cable and the insulator layer 3 is made uniform as described above. In order to ensure the AC breakdown electric field strength, a certain surface pressure (interface surface pressure) is required over the entire interface, but by making the surface pressure uniform, the portion below the required surface pressure can be eliminated. , Electrical characteristics are improved.
Further, since the interface pressure is made uniform, the basic fitting diameter difference (fitting diameter difference with respect to the similar fan shape) can be suppressed as small as possible. That is, it is not necessary to excessively increase the basic fitting diameter difference in order not to generate a portion having a required surface pressure or less. Since the work of inserting the cable insulation layer into the cable adapter is easier as the fitting diameter difference is smaller, the workability can be improved by minimizing the basic fitting diameter difference as described above. be able to.
Since the electrical characteristics are improved, the insulation thickness and the creeping length of the insulating part of the premolded insulator 12 can be shortened, and the terminal connection part can be downsized.
In addition, as described above, the cable terminal processing length can be shortened, the insulation thickness of the pre-molded insulator 12 and the creeping length of the insulation portion can be shortened, and the workability is improved, so that the termination connection portion can be reduced. Cost reduction is possible.

As shown in FIG. 6, the vicinity of the center of the fan-shaped arc 13b may be selected as a portion for increasing the fitting diameter difference in the cable insertion hole 13. In this case, for example, as shown in the figure, the radius R ₂ of the fan-shaped arc 13b is made larger than the radius R ₂ ′ of the similar fan-shaped arc, and the center position P of the radius R _{2 is set to} the radius R of the similar fan-shaped arc. _By lowering from the center position P ′ of ₂ ′, the fitting diameter difference can be partially increased.
The effect in this case is substantially the same as the above-mentioned Example.

The fan-shaped corner of the cable insertion hole 13 may have the same radius as the corner of the fan-shaped corner similar to the cross-sectional shape of the cable insulator layer. However, as shown in the cable insertion hole 13 of FIG. Earl R ₃ Earl R ₃ of the sector angle of the similar sector _'larger than, and the radius R ₃ of the center position radius R of the fan angle of the similar sector the Q _3' shifted inward from the central position Q 'of As a result, the fitting diameter difference of this portion may be increased.
As a result, the sector circumference is shortened, but when the sector circumference is shortened, there is an effect that the surface pressure on the circumference increases as a whole. Such an effect of increasing the overall surface pressure is caused by other portions than the fan-shaped corner portion 13c (13c ′) (the fan-shaped straight portion 13a (13a ′), the arc 13b (13b ′), the main 13d (13d ′), etc.). As a result, the surface pressure distribution becomes uniform.

The material of the cable adapter and the pre-molded insulator is not limited to the EP rubber of the embodiment, and other insulating rubbers can be used.
Moreover, although the compact power cable of an Example consists of three cable cores, it is not limited to this.
Moreover, the use of the power cable is not limited to a cable used for wiring of devices, vehicles, ships, etc., and can be applied to power cables of various wirings.

It is sectional drawing of the termination | terminus connection part structure of the compact type power cable of one Example of this invention. (A) is an AA enlarged sectional view of FIG. 1, (B) is shown for comparison with the present invention, and the cable insertion hole of the cable adapter is similar to the outer shape of the cable insulator layer. FIG. 2 (a) and 2 (b) are enlarged views of the shape of the cable insertion hole of the cable adapter. (A) is the shape of the cable insertion hole of FIG. 2 (b), and (b) is FIG. B) The shape of the cable insertion hole. (A) is an enlarged view showing only the cable adapter in FIG. 1, (b) is a view of (a) seen from below, and (c) is a cross-sectional view taken along the line BB of (a). (A) is CC sectional drawing of FIG. 4 (a), (b) is the figure which looked at (a) from the bottom. It is a figure which shows the other Example about the shape of a cable insertion hole. It is a figure which shows the further another Example about the shape of a cable insertion hole. In the case of the cable adapter of the embodiment of the present invention (FIG. 4, FIG. 5, FIG. 2 (A), FIG. 3 (A)) (FIG. 8 (B)), and the comparative example (FIG. 2 (B), FIG. B)) In the case of the cable adapter (FIG. 8 (a)), the diagram showing the result of analyzing the interfacial pressure distribution with the cable insulator layer using the finite element method, FIG. It is a figure which shows each position of A, B, C in FIG. An example of the compact type power cable which is the object of the present invention is shown. (A) is a cross-sectional view of the compact type power cable, (B) is a part up to the cable insulator layer of one cable core in (A). It is sectional drawing shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductor 2 Internal semiconductive layer 3 Cable insulator layer 4 External semiconductive layer 5 Cable core 6 Shielding layer 7 Sheath 8 Compact type power cable 10 Termination connection structure 11 of compact type power cable 11 Cable adapter 12 Premolded insulator 13 Cable Insertion hole 13 'Conventional cable insertion hole 13a (13a') R-shaped portion 13b (13b ') of the fan-shaped straight portion 13c (13c') near the center of the fan-shaped arc Fan-shaped corner portion 14 Circular hole 15 Cable-side insulating cylindrical portion 16 Equipment Side insulating cylinder 18 Insulator 19 Internal semiconductive layer 20 External semiconductive layer 22 Cap

Claims (7)

The end of a compact power cable in which a plurality of fan-shaped cross-section cable cores, in which an inner semiconductive layer, a cable insulator layer, and an outer semiconductive layer are formed in order on the outer periphery of a conductor having a fan-shaped cross section, are twisted and sheathed A connection structure,
A cable insulation layer of the cable core is fitted into the cable insertion hole of the cable adapter, which is a cylindrical rubber insulator having a fan-shaped cable shape and a circular outer shape, and the cable adapter portion is circular with a pre-molded insulator. A compact power cable terminal connection structure characterized by being fitted into a hole. A cable adapter for use in the terminal connection structure of a compact power cable according to claim 1,
The cable insertion hole is similar to the cross-sectional shape of the cable insulation layer, and the cable insertion hole and the cable are in a region where the interface pressure is reduced when the cable insulation layer is fitted as a smaller fan-shaped (similar fan-shaped) cross section. A cable adapter for a terminal connection structure of a compact power cable, characterized in that it has a cross-sectional shape in which a difference in fitting diameter with an insulator layer is further increased.   The cable adapter according to claim 2, wherein a region for further increasing a fitting diameter difference in the cable insertion hole is a fan-shaped linear portion. Wherein the straight portion of the sector, the cable adapter according to claim 3, characterized in that to increase the fit diameter difference fan straight portion by providing the radius R ₁ of the inwardly convex.   3. The cable adapter according to claim 2, wherein a region for further increasing the fitting diameter difference in the cable insertion hole is near the center of the fan-shaped arc. Earl R ₂ sectorial arc of the cable insertion hole radius R ₂ of similar sector-shaped arc _'larger than, and the Earl centered position similar fan-shaped arc of radius R ₂ of the R _2' to lower than the center position of the 6. The cable adapter according to claim 5, wherein the fitting diameter difference near the center of the fan-shaped arc is increased. The radius R ₃ of the fan-shaped corner, which is a region where the interfacial pressure is increased, is made larger than the radius R ₃ ′ of the fan-shaped corner of the similar fan-shaped, and the center position of the radius R ₃ is the radius of the fan-shaped corner of the similar fan-shaped The cable adapter according to claim 2, wherein the cable adapter is shifted inward from the center position of R ₃ ′.

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