JP2000125434A - Tool for thinning external semiconductive layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to quickly, easily and uniformly shave the external semiconductive layer of a power cable, by fixing a cutting edge on a cable shaving-side movable frame so that the cutting edge is protruded from a shaving-side guide roller. SOLUTION: A rotational knob 21 is turned so that the axis 41 of a prepared power cable 40 to be shaven is positioned in the center of the tool for thinning external semiconductive layers, and the power cable is set and supported there. A cutting edge 30 is fixed on a cable shaving-side movable frame 25 so that the cutting edge is slightly protruded inward through a cutting edge stopper 31. An external semiconductive layer is shaven by a thickness equivalent to the distance of this protrusion. Therefore, the thickness of an external semiconductive layer to be shaven can be increased or decreased as desired by adjusting the distance of the protrusion of the cutting edge 30. Then the external semiconductive layer of the power cable 40 to be shaven can be precisely, quickly and easily shaven to a uniform thickness in the circumferential direction by an operator's just turning the grip 26 by hand.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer semiconductive layer thinning tool. More specifically, the present invention relates to an external semiconductive layer thinning tool that can cut an external semiconductive layer of a power cable to a uniform thickness.

[0002]

2. Description of the Related Art Power cables play an important role as power transmission line members.

Since this type of power cable transmits power, its outer diameter is large. For this reason,
The length of the power cable that can be wound on the winding drum is limited, and as a result, the length per strip is limited.

[0004] On the other hand, the installation line of the power cable is considerably long. For this reason, in the installation work of the power cable, the connection work between the terminals of the power cable is frequently performed.

[0005] Power cables are roughly classified into oil-filled insulated power cables (generally called OF cables) and polymer-insulated power cables (rubber-insulated power cables and plastic-insulated power cables). Is done. Since these power cables are laid on high-voltage lines, their main components are composed of a stranded conductor, an inner semiconductive layer, an insulating layer, an outer semiconductive layer, a sheath layer, a metal shielding layer, and the like.

[0006] It is known that, when a current flows through a conductor in a power cable with a metal sheath, a small amount of circulating current is generated in the metal sheath layer. It is also known that Joule heat is generated in the metal sheath layer by this circulating current, and this causes a sheath circuit loss and an apparent power loss. Therefore, it is known to perform cross-bond grounding or one-end grounding in power cable laying work in order to eliminate such sheath circuit loss.

FIG. 5 is an explanatory plan view showing a construction section in which three lines of a single-core power cable with a metal sheath are constructed by a cross-bond grounding method.

In FIG. 5, reference numeral 1 denotes a power cable with a metal sheath, 2 denotes a metal sheath layer electrically insulating portion, and 3 denotes a bond wire. Here, a portion indicated by “‖” in the metal sheath layer electrical insulation portion 2 means a portion of the power cable 1 with a metal sheath that is not electrically connected to the metal sheath layer, that is, a metal sheath insulated connection portion.

That is, in the construction section constructed by the cross-bond grounding method, a metal sheath layer electrical insulation section 2 is provided along the laid three-line power cable 1 with a metal sheath, and the metal sheath layers are bonded so as to cross each other. Connect with line 3.

FIG. 6 is an explanatory plan view showing a construction section in which three lines of a single-core power cable with a metal sheath are constructed by a one-end grounding method.

In FIG. 6, reference numeral 1 denotes a power cable with a metal sheath, 2 denotes a metal sheath layer electrically insulating portion, and 4 denotes a ground wire.

That is, in the construction section constructed by the one-end grounding method, the metal sheath layer electric insulation section 2 is provided along the laid three lines of the power cable with metal sheath 1, and one end of the metal sheath layer electric insulation section 2 is provided. Ground wire 4 with metal sheath layer
Connect with.

Now, a potential difference is generated in the electric insulation portion 2 of the metal sheath layer shown in FIGS. 5 and 6 which increases in proportion to the single length of the single-core power cable with the metal sheath. Therefore, it is necessary to construct the metal sheath layer electrically insulating portion 2 to have a large outer shape in order to avoid electric field concentration. When the outer shape is increased, the metal sheath insulated connection occupies a large space and requires a high level of technology for its assembly. In addition, the installation of a large number of large-sized metal sheath layer electrically insulating portions 2 along the laid line of the power cable with a metal sheath has problems in terms of location and economy.

For this reason, the metal sheath layer electric insulation portion 2 which can effectively reduce the metal sheath circuit loss in the laid line of the power cable with the metal sheath has the best size.
And it is a rather difficult problem to install in the best position.

On the other hand, recent advances in power cable manufacturing technology and the increase in size of manufacturing equipment have made it possible to make the length of each power cable with a metal sheath considerably long. Accordingly, it has become necessary to efficiently perform cross-bond grounding at an arbitrary position in the length direction of the power cable with a long metal sheath per strip.

On the other hand, even on the power cable side with the metal sheath, the metal sheath layer is electrically insulated at any position in the length direction without greatly increasing the outer diameter of the cable, thereby reducing the circuit loss of the metal sheath layer. Power cables with metal sheaths have been developed.

FIG. 7 is a cross sectional view showing an example of such a power cable with a metal sheath.

In FIG. 7, 10 is a stranded copper conductor, 11 is an inner semiconductive layer, 12 is an insulating layer, 13 is an outer semiconductive layer, 14
Is a corrugated metal shielding sheath layer.

That is, the power cable with a metal sheath shown in FIG. 7 has an inner semiconductive layer 11, an insulating layer 12, an outer semiconductive layer 13, and a corrugated metal shielding sheath layer 14 sequentially provided on a stranded copper conductor 10. It consists of

Here, the corrugated metal shielding sheath layer 14
Is a metal, for example, aluminum, which is extruded and coated so as to have a corrugation. However, as a metal sheath layer, a metal tape may be wound or laid longitudinally, or a metal wire may be wound.

FIG. 8 is a semi-longitudinal sectional view showing the electric insulation portion of the metal sheath layer of the power cable with the metal sheath shown in FIG.

In FIG. 8, 10 is a stranded copper conductor, 11 is an inner semiconductive layer, 12 is an insulating layer, 13 is an outer semiconductive layer, 14
Is a corrugated metal shielding sheath layer, 15 is an electrode, 16 is an external protection tube, and 17 is a sealing material.

That is, in the electric insulation portion of the metal sheath layer of the power cable with the metal sheath shown in FIG. 8, first, the corrugated metal shielding sheath layer 14 at an arbitrary position in the longitudinal direction of the power cable with the metal sheath is cut and removed. Secondly, the electrodes 15, 15 are inserted and fixed at both ends of the cut and removed corrugated metal shielding sheath layer 14, and thirdly, the cut and removed corrugated metal shielding sheath layer 14 is removed. Both ends and electrode 1
Fourth, an outer protective tube 16 is placed on the upper side of the outer protective tube 16, and fourthly, both ends of the outer protective tube 16 are sealed by sealing materials 17, 17.

Here, the outer protective tube 16 also serves as an insulating tube. As a result, electrical continuity is cut off outside the insulating layer 12 at the electrically insulated connecting portion of the metal sheath layer of the power cable with the metal sheath, except for the external semiconductive layer 13.

However, in the electric insulation portion of the metal sheath layer of the power cable with the metal sheath shown in FIG.
Remains unremoved, and there is a troublesome problem that the external semiconductive layer 13 generates heat.

That is, when an AC current having a commercial frequency is applied to a power cable having a metal sheath, a voltage is constantly generated between the electrodes 15 by electromagnetic induction of the stranded copper conductor 10, and the voltage causes a corrugated metal shielding sheath layer. A current flows through the outer semiconductive layer 13 remaining in the portion where 14 has been cut and removed. In addition, a charging current is generated in the insulating layer 12, and the charging current passes through the outer semiconductive layer 13 remaining in the portion where the corrugated metal shielding sheath layer 14 has been cut and removed. Flows to The external semiconductive layer 13 remaining in the portion where the metal shielding sheath layer 14 has been cut and removed by these currents generates heat, and the generated heat causes the temperature of the stranded copper conductor 10 to rise. There is also a concern that the temperature will exceed the allowable temperature.

In order to suppress the heat generation of the outer semiconductive layer 13 remaining in the portion where the metal shielding sheath layer 14 has been cut and removed, the outer semiconductive layer 13 in this portion is scraped off to reduce the thickness. A measure has been taken to increase the electrical resistance in the part and to reduce the flowing current, thereby reducing the heat generation in this part.

Conventionally, a method of shaving the outer semiconductive layer 13 in the metal sheath layer electrically insulating portion by a worker using a glass sharpener has been performed.

[0029]

However, the electric insulation portion of the metal sheath layer of the power cable with the metal sheath is provided at a number of places along the longitudinal direction of the power cable with the metal sheath. Therefore, the work of shaving the outer semiconductive layer 13 in the metal sheath layer electrically insulating portion is performed at the site where the power cable with the metal sheath is laid. For this reason, in the work of shaving the outer semiconductive layer 13 with a glass sharpener, it is difficult to uniformly and thinly cut the outer semiconductive layer 13 of the power cable over the entire circumference, and the burden on the operator is large. The efficiency was poor. In particular, it is difficult to cut the outer semiconductive layer 13 on the lower side of the laid power cable. Here, if it is cut too deeply, the outer semiconductive layer 13 disappears, and the insulating layer 12 is exposed. As a result, the electric field in that portion increases, and the fear of electric breakdown increases.

The present invention has been made in view of the foregoing, and has as its object to solve the above-mentioned disadvantages of the prior art, and to provide an external semiconductive layer of a power cable quickly, easily and uniformly. An object of the present invention is to provide an external semiconductive layer thinning tool which can be sharpened.

[0031]

The gist of the present invention resides in that a shaft having a rotating knob fixed at one end thereof is screwed to an intermediate portion of the shaft so as to be movable along the shaft. Cable-side clamping frame, a cable cutting-side fixed frame having a guide roller rotatably mounted inside the cable] -side clamping frame, and a grip fixed to the other end of the shaft. A cable cutting side movable frame installed on the upper side of the cable cutting side fixed frame via a stopper and a spring, and a cutting side guide installed to be rotatable on the cable cutting side movable frame. A roller and a cutting blade 30 fixed to the cable cutting side movable frame so as to protrude from the cutting side guide roller. In outer semiconducting layer thinning tool to.

In the present invention, it is preferable that at least two guide rollers are provided inside the cable-type holding-side frame so as to hold the power cable at an accurate position.

In the present invention, it is preferable that the guide roller and the cutting-side guide roller installed inside the cable] -shaped holding-side frame are constructed so that their diameters can be varied.

In the present invention, the guide roller and the cutting-side guide roller provided inside the cable] -shaped holding-side frame can be slightly shifted with respect to the central axis of the power cable whose fixed shaft angle is reduced. It is preferable that it is constituted.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the outer semiconductive layer thinning tool of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory front view showing a state in which a power cable to be ground is held by an embodiment of an external semiconductive layer thinning tool according to the present invention.

In FIG. 1, reference numeral 20 denotes a shaft, 21 denotes a rotary knob, 22 denotes a cable] clamping side frame, 23 denotes a screw push, 24 denotes a cable cutting side fixed frame, 25 denotes a cable cutting side movable frame, and 26 denotes a grip. 27,
28 is a stopper, 29 is a spring, 30 is a cutting blade,
31 is a blade stopper, 32 is a cutting-side guide roller, 33
Is a cutting-side roller shaft, 34 is a lower roller supporting member, 35 is an upper roller supporting member, 36 is a lower guide roller, 37 is an upper guide roller, 38 is a lower roller shaft, 39 is an upper roller shaft, and 40 is a power cable for grinding. , 41 are central axes of the grinding power cable.

That is, in the outer semiconductive layer thinning tool according to one embodiment of the present invention, a rotating knob 21 is fixed to one end of a shaft 20. In the middle of the shaft 20, a cable] type holding frame 22 is screwed. A lower roller supporting member 34 is fixed to the lower portion of the inner side of the cable] type holding frame 22, and the lower roller supporting member 34 is connected to the lower guide roller 3 via a lower roller shaft 38.
6 is installed so that it can rotate. An upper roller supporting member 35 is fixed to the upper inside of the cable-type holding side frame 22, and the upper guide roller 3 is connected to the upper roller supporting member 35 via an upper roller shaft 39.
7 is installed so that it can rotate.

On the other hand, a cable cutting-side fixed frame 24 is fixed to the other end of the shaft 20. A grip 2 is provided at the other end of the cable cutting side fixed frame 24.
6 is fixed, and a cable cutting side movable frame 25 is mounted on the upper side thereof via stoppers 27 and 28 and a spring 29 so as to be movable.
A cutting blade 30 is fixed to the cable cutting side movable frame 25 via a blade stopper 31 so as to slightly protrude inward. Further, the cutting side guide roller 32 can be rotated via a cutting side roller shaft 33. It is installed as follows.

FIG. 2 is an enlarged sectional view taken on line AA of FIG.

In FIG. 2, 25 is a movable frame on the cable cutting side, 30 is a cutting blade, 31 is a blade stopper, 32 is a cutting side guide roller, and 33 is a cutting side roller shaft.

As can be seen from FIG. 2, the cutting blade 30 is fixed to the cable cutting side movable frame 25 via the blade stopper 31 so as to slightly protrude inward.
FIG. 2 is an enlarged sectional view taken along line BB of FIG. 1.

In FIG. 3, reference numeral 34 denotes a lower roller supporting member;
36 is a lower guide roller.

As can be seen from FIG. 3, a lower guide roller 36 is rotatably supported by the lower roller support member 34.

Although not shown, a lower guide roller 37 is similarly rotatably supported by the upper roller support member 35.

FIG. 4 is an enlarged sectional view taken on line CC of FIG.

In FIG. 4, 24 is a fixed frame on the cable cutting side, 25 is a movable frame on the cable cutting side, and 29 is a spring.

As can be seen from FIG. 4, a spring 29 is provided between the fixed frame 24 on the cable cutting side and the movable frame 25 on the cable cutting side.

Next, a description will be given of a working method of shaving the external conductive layer of the power cable using the external semiconductive layer thinning tool according to one embodiment of the present invention.

First, in the power cable, layers located outside the portion where the outer conductive layer is shaved, for example, a sheath layer, a corrugated metal shielding sheath layer, an intervening layer, and the like are deleted or removed.

Next, as shown in FIG. 1, the center of the grinding power cable 40 of the grinding power cable 40 prepared above is placed at the center of the outer semiconductive layer thinning tool of one embodiment of the present invention.
The turning knob 21 is turned so as to come on and mounted and supported.

As described above, the cutting blade 30 is fixed to the cable cutting side movable frame 25 via the blade stopper 31 so as to slightly protrude inward, and the thickness of the cutting blade 30 corresponds to the protruding distance. The outer semiconductive layer will be shaved. Therefore, the thickness of the external semiconductive layer can be arbitrarily adjusted by adjusting the distance the cutting blade 30 protrudes.

Next, by simply rotating the grip 26 with the hand, the outer semiconductive layer of the power cable for grinding 40 is accurately and quickly formed to a uniform thickness in the circumferential direction.
Moreover, it can be easily cut.

This is because the outer semiconductive layer can only be cut by a thickness corresponding to the distance that the cutting blade 30 protrudes, and the cable cutting side movable frame 25 that supports the cutting blade 30
Since the spring 29 is mounted on the
This is because the distance between 0 and the outer peripheral surface of the grinding power cable 40 is always kept constant. The spring 29 can easily follow the power cable 40 for grinding even if it is slightly deformed in the length direction. As a result, the outer semiconductive layer can be cut to a constant thickness.

In the external semiconductive layer thinning tool according to one embodiment of the present invention, the diameter of the cutting side guide roller 32, the lower guide roller 36, and the upper guide roller 37 is changed, or the cutting side roller shaft is changed. 33, the lower roller shaft 38 and the upper roller shaft 39 are slightly shifted relative to the central axis 41 of the power cable for grinding, so that the outside of the embodiment of the present invention is fixed at a constant pitch every time one round is cut. The external semiconductive layer can be cut while the semiconductive layer thinning tool is advanced in the longitudinal direction of the power cable 40 for grinding.

Table 1 shows the result of shaving the outer conductive layer of the power cable using the outer semiconductive layer thinning tool according to one embodiment of the present invention and the outer side of the power cable using a conventional glass sharpener. It is a comparison with the result of shaving the conductive layer.

[0057]

[Table 1]

As can be seen from Table 1, when the outer conductive layer of the power cable is shaved with a conventional glass sharpener, the thickness of the outer conductive layer varies from 1.2 mm to 0.8 mm, and the shaving time is reduced. It took 45 minutes.

On the other hand, when the outer conductive layer of the power cable is cut using the outer semiconductive layer thinning tool of one embodiment of the present invention, the thickness of the outer conductive layer is 1.0 mm to 1 mm. .0
mm and no variation was observed, and the shaving time could be reduced to 15 minutes.

[0060]

According to the present invention, when the outer conductive layer of a power cable is cut using the outer semiconductive layer thinning tool of the present invention, the thickness of the outer conductive layer can be cut uniformly without any variation. The time can be remarkably shortened, whereby the electric loss of the laid power cable can be effectively reduced and the electric reliability can be remarkably improved, which is industrially useful.

[Brief description of the drawings]

FIG. 1 is an explanatory front view showing a state in which a power cable to be ground is held by an embodiment of an external semiconductive layer thinning tool according to the present invention.

FIG. 2 is an enlarged sectional view taken on line AA of FIG. 1;

FIG. 3 is an enlarged sectional view taken on line BB of FIG. 1;

FIG. 4 is an enlarged sectional view taken on line CC of FIG. 1;

FIG. 5 is an explanatory plan view showing a construction part in which three lines of a single-core power cable with a metal sheath are constructed by a cross-bond grounding method.

FIG. 6 is an explanatory plan view showing a construction part in which three lines of a single-core power cable with a metal sheath are constructed by a one-end grounding method.

FIG. 7 is a cross-sectional view showing an example of a power cable with a metal sheath.

FIG. 8 is a semi-longitudinal sectional view showing a metal sheath layer electric insulating portion of the power cable with a metal sheath shown in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power cable with metal sheath 2 Metal sheath layer electrical insulation part 3 Bond wire 4 Ground wire 10 Twisted copper conductor 11 Internal semiconductive layer 12 Insulating layer 13 External semiconductive layer 14 Corrugated metal shielding sheath layer 15 Electrode 16 External protective tube DESCRIPTION OF SYMBOLS 17 Seal material 20 Shaft 21 Rotating knob 22 Cable] Forming side frame 23 Screw push 24 Cable cutting side fixed frame 25 Cable cutting side movable frame 26 Grip 27, 28 Stopper 29 Spring 30 Cutting blade 31 Blade stopper 32 Cutting side guide roller 33 Cutting-side roller shaft 34 Lower roller support member 35 Upper roller support member 36 Lower guide roller 37 Upper guide roller 38 Lower roller shaft 39 Upper roller shaft 40 Power cable for grinding 41 Power cable central axis for grinding

Claims (4)

[Claims] 1. A shaft having a rotating knob fixed to one end of a shaft, a cable] -type holding frame screwed to an intermediate portion of the shaft so as to be movable along the shaft, and the cable]. A guide roller rotatably mounted inside the holding frame, a cable cutting side fixed frame having a grip fixed to the other end of the shaft, and a stopper on the upper side of the cable cutting side fixed frame. And a cable cutting-side movable frame installed so as to be movable via a spring, a cutting-side guide roller installed so as to be rotatable on the cable cutting-side movable frame, and a cable protruding from the cutting-side guide roller. An external semiconductive layer thinning tool comprising a cutting blade fixed to a cable cutting side movable frame. 2. A tool for reducing the thickness of an outer semiconductive layer according to claim 1, wherein at least two guide rollers are provided inside the frame. 3. The outer half according to claim 1, wherein the guide roller and the cutting-side guide roller installed inside the cable-holding-side frame are configured so that their diameters can be varied. Conductive layer thinning tool. 4. The cable] The guide roller and the cutting-side guide roller installed inside the holding-side frame are configured such that their fixed shaft angles can be slightly shifted with respect to the central axis of the power cable for reducing the angle. The tool for thinning an external semiconductive layer according to claim 1, wherein: