JPH06188034A - Sector type conductor connecting sleeve and sector type conductor connecting method thereof - Google Patents

Abstract

PURPOSE:To provide high connection strength without lengthening a connecting sleeve, by making the outer peripheral surface of the middle part of a connecting sleeve, on which a conductor insertion hole is formed, be a small diameter port; and on the one hand making the outer peripheral surface of both the end parts of the connecting sleeve be a large diameter cylindrical surface. CONSTITUTION:A connecting sleeve 20, on which a conductor insertion hole 21 having a sector type cross section along an axis direction is penetratedly formed, is composed of good conductive material, and is made to form a hollow tube state as a whole. In the middle part 22 having a length of L1 out of the overall length of the sleeve 20, the outer peripheral surface of the middle part 22 is made a small diameter cylindrical surface 22A having a diameter of R1; and in the parts (both end parts) 23 and 24 having lengthes L2 and L3 adjoining on both the sides of the middle part 22, the respective outer peripheral surfaces are made a large diameter cylindrical surface 23A of R2>R1 respectively. Since an outer shape difference exists between both the sides, compressing the connecting sleeve from its outer peripheral surface side, so as to make equal the outer diameters of the middle part and both the end parts, surely and effectively prevents the falling-out of a sector type conductor from the connecting sleeve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductor having a fan-shaped cross section, that is, a connecting sleeve for connecting electric power cables using the fan conductor, and connecting the fan conductors using the connecting sleeve. It is about how to do it.

[0002]

2. Description of the Related Art Recently, mainly for the purpose of compacting rubber / plastic power cables such as cross-linked polyethylene power cables (CV cables),
As a high voltage cable of 66 kV class, a cable using a fan-shaped conductor having a fan-shaped cross section is about to be put into practical use. An example of a 3-core CV cable using such a fan-shaped conductor is shown in FIG.

In FIG. 11, each of the three fan-shaped conductors 1 is formed by twisting a plurality of good-conductivity wire rods such as copper wire rods and forming a fan-shaped cross section. Each fan-shaped conductor 1 is provided with an inner semiconductive layer 2, an insulator layer 3, an outer semiconductive layer 4, and a shielding layer 5 in that order from the inside on the outer periphery, and these three are circular as a whole. The anticorrosion layer 6 is provided on the outer circumference of the entire structure.

By the way, conventionally, a cable using a fan-shaped conductor is exclusively used only for a low voltage of 22 kV to 33 kV or less. As a cable for such a low voltage, a soldering sleeve is generally used for connecting conductors. Was used. On the other hand, in a high-voltage cable of 66 kV class or higher using an ordinary circular conductor, a sleeve compression connection method has been conventionally used for connecting conductors. This sleeve compression connection method does not use fire unlike the connection method using the soldering sleeve, and there is no difference in other performance from the connection method using the soldering sleeve. Even when the used cable is put to practical use in the 66 kV class or more, it is considered to apply the sleeve compression connection method.

In the sleeve compression connection system, generally, the conductor layers are exposed by removing the insulating layer or the like at each cable end, the exposed ends of each conductor are inserted into the connecting sleeve from both sides thereof, and then the sleeve is compressed. And connecting the conductors to each other. When applying such a sleeve compression connection method to the connection of the fan-shaped conductors as described above, a connecting sleeve 20 as shown in FIGS. 12 and 13 is generally used. Is being considered. This connecting sleeve 20
Except for the tapered portions 20A at both ends, is formed into a cylindrical shape so as to have substantially the same outer diameter as a whole, and the conductor insertion holes 10, 1 having a sectoral cross section along the axial direction from both end sides thereof.
1 is formed.

[0006]

When the fan-shaped conductors are connected to each other by the sleeve compression connection method using the connecting sleeve as described above, there are the following problems.

That is, when the conductors are connected to each other using the connecting sleeve, in order to sufficiently increase the connecting strength, that is, the limit strength that the connecting portion can withstand the force in the pulling direction with respect to the conductor, the conductor insertion hole is required. It is necessary to increase the contact area between the conductor surface and the inner surface of the conductor insertion hole by increasing the length of the connection sleeve, but in this case the length of the connection sleeve will inevitably become longer, and the material cost and processing cost of the connection sleeve will increase. In addition, there is a problem in the sleeve compression work after inserting the conductor end into the conductor insertion hole. Therefore, it has been desired to develop a method capable of increasing the connection strength without increasing the length of the connecting sleeve.

The present invention has been made in view of the above circumstances, and when connecting the fan-shaped conductors by the sleeve compression connection method, a sufficiently high connection strength can be obtained without increasing the length of the connection sleeve. An object of the present invention is to provide a sleeve for connecting a fan-shaped conductor and a method for connecting a fan-shaped conductor using the sleeve.

[0009]

In order to solve the above-mentioned problems, in the present invention, the shape of the connecting sleeve, especially the outer peripheral surface thereof, is made to be a shape that has not been considered in the past. .

That is, in the fan-shaped conductor connecting sleeve of the first aspect of the present invention, conductor insertion holes having a fan-shaped cross section are formed from both ends along the axial direction, and the outer peripheral surface of the central portion in the axial direction has a small diameter. It is characterized in that it is a cylindrical surface, and the outer peripheral surfaces of both end portions adjacent to the central portion are large diameter cylindrical surfaces.

The inventions of claims 2 and 3 relate to a method of connecting the fan-shaped conductors using the sleeve as described above.

[0012] Specifically, in the invention of claim 2, in connecting the ends of the fan-shaped conductors having a fan-shaped cross section, the conductor insertion holes of the connecting sleeve are formed from both end sides thereof. A method of connecting a fan-shaped conductor by inserting the end of the fan-shaped conductor and compressing the sleeve from the outer peripheral side thereof, wherein the conductor insertion hole has a fan-shaped cross section as the connecting sleeve. , A sleeve is prepared in which the outer peripheral surface of the central portion in the axial direction is a small-diameter cylindrical surface, and the outer peripheral surfaces of both end portions adjacent to the central portion are large-diameter cylindrical surfaces. After being inserted into the insertion hole, the large-diameter cylindrical surface of both ends of the connecting sleeve is compressed from the outer peripheral side until the diameter becomes the same as the outer diameter of the small-diameter cylindrical surface of the central portion. is there.

According to a third aspect of the present invention, when connecting the ends of the fan-shaped conductor having a fan-shaped cross section, the fan-shaped conductor is inserted into the conductor insertion hole of the connecting sleeve in which the conductor insertion holes are formed from both ends. In the sleeve connecting method of the fan-shaped conductors, in which the fan-shaped conductors are connected by inserting the end portions and compressing the sleeve from the outer peripheral side thereof, as the connecting sleeve, the conductor insertion hole has a fan-shaped cross section, and an axial direction. Prepare a sleeve in which the outer peripheral surface of the central portion is a small-diameter cylindrical surface, and the outer peripheral surfaces of both end portions adjacent to the central portion are large-diameter cylindrical surfaces, and insert the end of the fan-shaped conductor into the conductor insertion hole. After that, the small-diameter cylindrical surface of the central portion of the connecting sleeve is compressed from the outer peripheral side until its diameter reaches a predetermined finished diameter, and then the large-diameter cylindrical surface of both end portions of the connecting sleeve is
It is characterized in that the outer peripheral surface side is compressed until the diameter becomes the same as the finished diameter of the central portion.

[0014]

The fan-shaped conductor connecting sleeve of the first aspect of the invention is
The axial center part and its both sides (both ends)
Have different outer diameters, the outer peripheral surface of the central portion is a small-diameter cylindrical surface having a relatively small diameter, and the outer peripheral surfaces of both end portions are large-diameter cylindrical surfaces having a relatively large diameter. When connecting fan-shaped conductors using such a connecting sleeve, insert the end of the fan-shaped conductor to be connected into the conductor insertion hole of the fan-shaped cross section of the connecting sleeve, and then use a round die or hexagonal die. By using the connecting sleeve, the connecting sleeve is compressed from the outer peripheral surface side, and the inner surface of the conductor insertion hole and the outer surface of the fan-shaped conductor are pressed against each other. By the way, in connection of a conductor in a general power cable, it is desired that the outer diameter of the sleeve after connection of the conductor is substantially uniform over the entire length from the viewpoint of winding an insulating tape on the outer circumference of the connection sleeve. Therefore, even when the connecting sleeves having different outer diameters at the central portion and the both end portions as described above are used, when the connecting sleeve and the fan-shaped conductor are compressed for crimping, the connecting sleeve is substantially provided over the entire length thereof. It is desirable to deform them so that they have the same diameter. In the case of compressive deformation so as to have the same diameter after compression as described above, a difference occurs in the amount of deformation between both end portions, which were initially large in diameter, and the central portion, which was small in diameter. There is also a difference in the amount of deformation. Therefore, the cross-sectional dimension and cross-sectional shape of the fan-shaped conductor after compression differ between the central portion and both end portions of the connecting sleeve, and such a difference causes a mechanical anchoring effect and is high against the force in the conductor pulling direction. It indicates the connection strength.

The operation of the compression as described above will be concretely described with respect to the method of the invention of claim 2. According to the method of the invention of claim 2, after inserting the end portion of the fan-shaped conductor into the conductor insertion hole, only the end portions of the entire connecting sleeve, that is, the portion having the large-diameter cylindrical surface, has the diameter of the central portion. That is, the compression is performed until the outer diameter of the small diameter cylindrical surface becomes equal to the outer diameter. By doing so, only the both ends of the connecting sleeve are reduced in diameter, the inner surface of the conductor insertion hole is crimped to the internal fan-shaped conductor at that part, and the fan-shaped conductors located inside the both ends are It is compressed and deformed. At this time, inside the both ends of the connecting sleeve (the part of the large-diameter cylindrical surface), the fan-shaped conductor is not only reduced in diameter but also does not deform uniformly because it originally has a fan-shaped cross section. , Is anisotropically compressed and deformed to have a cross-sectional shape different from the original fan shape (usually a shape closer to a circle than the fan shape before compression). On the other hand, since the central portion (portion of the small diameter cylindrical surface) of the connecting sleeve is not compressed, the inner sectoral conductor is not deformed, and the initial diameter and the initial sectoral shape are maintained. Therefore, of the respective parts of the fan-shaped conductor inserted into the conductor insertion holes of the connecting sleeve, the parts located inside both ends of the large diameter of the sleeve are compared with the parts located inside the small central part of the sleeve. And the cross-sectional shape is also different. Therefore, when a tensile force is applied to the fan-shaped conductor, the boundary between the portion corresponding to the central portion of the sleeve and the portions corresponding to both end portions of the sleeve as described above is The difference acts as an anchor to prevent the sector conductor from slipping out of the sleeve. Therefore, a large connection strength is exhibited with respect to the force in the pulling direction.

According to the third aspect of the invention, after the fan-shaped conductor is inserted, first, the central portion of the connecting sleeve, that is, the portion having the small diameter cylindrical surface is compressed to some extent (until a predetermined finished diameter), and then the connecting sleeve is connected. Both end portions of the sleeve, that is, a portion having a large-diameter cylindrical surface is compressed until the diameter thereof becomes the same as the finished diameter of the central portion. In this method, the central portion of the connecting sleeve is also compressed and deformed, but since the initial diameter of the central portion is smaller than that of both end portions, the degree of compression of the central portion is smaller than that of both end portions. Therefore, the degree of deformation of the fan-shaped conductor, which was located inside the small-diameter central part among the parts of the fan-shaped conductor inserted into the conductor insertion hole of the connecting sleeve, was also located inside the large-diameter end parts. It becomes smaller than the part. That is, as in the case of the method of the second aspect of the present invention, among the respective portions of the fan-shaped conductor, the portions located inside the large-diameter end portions of the connecting sleeve are the small-diameter central portions of the connecting sleeve. The diameter is smaller than that of the portion that was located inside, and the cross-sectional shape is also different. Therefore, the same anchor effect as described above prevents the fan-shaped conductor from slipping out of the sleeve, and exhibits a large connection strength against a force in the pulling direction. In the case of the method of the third aspect of the present invention, the inner surface of the conductor insertion hole and the outer peripheral surface of the fan-shaped conductor are crimped not only at both end portions but also at the central portion of the connecting sleeve. The electrical continuity is improved and the connection strength is further increased.

[0017]

1 to 3 show an example of a connecting sleeve according to the first aspect of the invention.

1 to 3, a connecting sleeve 20 is provided.
Is basically made of a good conductive material of the same material as the fan-shaped conductor to be connected. When the fan-shaped conductor is made of copper, copper is also used for the connecting sleeve 20, and the fan-shaped conductor is made of aluminum. In that case, an aluminum alloy is also used for the connecting sleeve 20. The connecting sleeve 20 is formed to have a hollow tubular shape as a whole by penetrating a conductor insertion hole 21 having a fan-shaped cross section along the axial direction.
Further, of the total length of the connecting sleeve 20, the length L ₁
The outer peripheral surface of the central portion 22 is a small-diameter cylindrical surface 22A having a diameter of R ₁ , and portions (both end portions) 23 and 24 of lengths L ₂ and L ₃ that are adjacent to both sides of the central portion 22 are respectively The outer peripheral surface is a large-diameter cylindrical surface 23A of R ₂ (> R ₁ ).

When connecting the fan-shaped conductors using the connecting sleeve 20 as described above, first, the two should be connected.
Each end 1A of the fan-shaped conductor 1 is inserted into the conductor insertion hole 21 of the connecting sleeve 20 from both sides thereof. And claim 2
In the case of the method of the invention, only the large-diameter cylindrical surfaces 23A and 24A of both end portions 23 and 24 are compressed from the outer peripheral surface side by a round die, a hexagonal die or the like. The compression of the both end portions 23, 24 is performed until the outer diameter thereof becomes the same as the diameter R ₁ of the small diameter cylindrical surface 22A of the central portion 22. In this way, the state after compression molding is applied only to both end portions 23 and 24 in FIG.
As shown in FIG.

As shown in FIG. 5, since the fan-shaped conductor 1 is not compressed in the central portion 22, its cross-sectional shape and cross-sectional dimensions are the same as in the initial state (see FIG. 2). On the other hand, in the both end portions 23 and 24, the fan-shaped conductor 1 is compressed as shown in FIG. 6, and the sectional size and shape are different from the initial size and shape before compression. Specifically, the maximum diameter of the cross section of the fan-shaped conductor 1 becomes smaller, and the cross-sectional shape becomes closer to a circle than the original fan shape. Therefore, in the compressed state of the connecting sleeve 20, the cross-sectional dimension and cross-sectional shape of the fan-shaped conductor 1 inside the sleeve central portion 22 and the both end portions 23 and 24 are different, especially in terms of the maximum diameter of the conductor cross section. Then, the portion located at the central portion 22 is larger than the portions located at both end portions 23 and 24. Therefore, near the boundary between the two, there is a step on the surface of the fan-shaped conductor 1 (the surface that is in contact with the inner surface of the conductor insertion hole 21 of the connecting sleeve 20), and that portion is mechanical with respect to the force in the conductor pulling direction. Functioning as an anchor, the fan-shaped conductor 1 can be effectively prevented from coming off. Therefore, high connection strength is exhibited with respect to the force in the conductor pulling direction.

On the other hand, an example of the method of the third aspect of the invention is shown stepwise in FIG. In this case, the connecting sleeve 2
After inserting the end portions 1A of the two conductors 1 to be connected from both sides into the conductor insertion hole 21 of 0, first, the connecting sleeve 20
The small-diameter cylindrical surface 22A having the outer diameter R ₁ of the central portion 22 is compressed from the outer peripheral surface side by a round die or the like to have a predetermined finished diameter R ₃ . After that, the outer diameter R of both end portions 23 and 24
_{The two} large-diameter cylindrical surfaces 23A and 24A are similarly compressed from the outer peripheral surface side with a round die or the like, and the diameter thereof is set to the above-mentioned central portion
The finished diameter R ₃ after compression is the same.

The situation after compression of the central portion 22 and both end portions 23, 24 of the connecting sleeve 20 in this case is shown in FIGS.
Shown in. In the central part 22 of the connecting sleeve 20, FIG.
As shown in (1), the cross-sectional shape of the internal fan-shaped conductor 1 is slightly deformed from the original fan-shaped shape before compression, and its maximum diameter is also slightly smaller. On the other hand, at both end portions 23 and 24 of the connecting sleeve 20, as shown in FIG. 9, the cross-sectional shape of the internal fan-shaped conductor 1 is largely deformed from the original fan shape before compression to a shape close to a circle, and its maximum The diameter is also considerably smaller. Therefore, the central portion 22 and the end portions 23, 24 of the connecting sleeve 20 have the fan-shaped conductor 1 inside thereof.
Since the cross-sectional shape and the maximum diameter are different, the anchor-shaped conductor 1 is prevented from coming off from the connecting sleeve 20 by the anchor effect as in the above-described example, and a high connection strength in the pulling direction is exhibited.

In each of the above embodiments, the connecting sleeve 20 has the conductor insertion hole 21 extending in series from one end to the other end, but as shown in FIG. The hole may be partitioned by the partition wall 30 in the middle, and the conductor insertion hole 21A on one end side and the conductor insertion hole 21B on the other end side may be separated. However, in this case, the length L ₁ of the central portion 22 having the small diameter cylindrical surface 22A needs to be sufficiently longer than the thickness T of the partition wall 30.

[0024]

According to the connecting sleeve of the first aspect of the present invention, the central portion of the connecting sleeve is provided with the conductor insertion holes having the line-shaped cross section for inserting the two fan-shaped conductors to be connected from both sides. The outer peripheral surface of is a small-diameter cylindrical surface, while the outer peripheral surfaces of both ends of the connecting sleeve are large-diameter cylindrical surfaces, and there is a difference in outer diameter between the two, so insert a fan-shaped conductor into the conductor insertion hole. Then, if the connecting sleeve is compressed from the outer peripheral surface side so that the outer diameters of the central portion and both end portions become equal, the central portion of the connecting sleeve among the respective portions of the fan-shaped conductor inserted in the connecting sleeve. The cross-sectional shape and cross-sectional dimensions differ between the part located inside the and the parts located inside both end parts of the connecting sleeve, and therefore, due to the anchor effect at the boundary between them, the fan-shaped The conductor is for connection It is reliably and effectively prevented from escaping from over blanking can exhibit high connection strength against tensile force. And since such a high connection strength can be obtained, it is not necessary to increase the total length of the connecting sleeve in particular, so that the connecting sleeve can be shortened for downsizing, and the material cost and processing cost of the connecting sleeve can be reduced as compared with the conventional one. Can also be lowered.

According to the sleeve connecting method of the second aspect of the invention and the third aspect of the invention, when the sector-shaped conductors are actually connected to each other by using the connecting sleeve as described above, particularly the length of the sleeve is increased. Without doing so, the fan-shaped conductors can be actually connected to each other with high connection strength.

[Brief description of drawings]

FIG. 1 is a partially longitudinal side view showing an example of a connecting sleeve of the invention of claim 1.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view taken along the line BB or the line CC of FIG.

FIG. 4 is a method of connecting a sleeve according to the invention of claim 2,
It is a vertical side view which shows an example of the state after compressing the connection sleeve.

5 is a cross-sectional view taken along the line DD of FIG.

6 is a cross-sectional view taken along the line EE or the line FF in FIG.

FIG. 7 is a schematic diagram showing stepwise an example of the sleeve connecting method of the invention of claim 3;

8 is a cross-sectional view taken along the line GG in FIG.

9 is a cross-sectional view taken along the line HH or the line II of FIG.

FIG. 10 is a partial vertical cross-sectional side view showing another example of the connecting sleeve of the first aspect of the invention.

FIG. 11 is a cross-sectional view showing a typical example of a 3-core CV cable using a fan-shaped conductor.

FIG. 12 is a partially longitudinal side view showing a connecting sleeve which is conventionally considered to be used for connecting fan-shaped conductors by a sleeve compression connection method.

13 is a cross-sectional view taken along line JJ or KK of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 fan-shaped conductor 1A end part 20 connection sleeve 21, 21A, 21B conductor insertion hole 22 central part 22A small diameter cylindrical surface 23, 24 both ends 23A, 24A large diameter cylindrical surface

[Procedure amendment]

[Submission date] October 20, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a partially longitudinal side view showing an example of a connecting sleeve of the invention of claim 1.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view taken along the line BB or the line CC of FIG.

FIG. 4 is a vertical cross-sectional side view showing an example of a state after the connecting sleeve is compressed in the sleeve connecting method of the invention of claim 2;

5 is a cross-sectional view taken along the line DD of FIG.

6 is a cross-sectional view taken along the line EE or the line FF in FIG.

FIG. 7 is a schematic diagram showing stepwise an example of the sleeve connecting method of the invention of claim 3;

8 is a cross-sectional view taken along the line GG in FIG.

9 is a cross-sectional view taken along the line HH or I-I of FIG.

FIG. 10 is a partial vertical cross-sectional side view showing another example of the connecting sleeve of the invention of claim 1;

FIG. 11 is a cross-sectional view showing a typical example of a 3-core CV cable using a fan-shaped conductor.

FIG. 12 is a partially longitudinal side view showing a connecting sleeve which is conventionally considered to be used for connecting fan-shaped conductors by a sleeve compression connection method.

13 is a cross-sectional view taken along line JJ or KK of FIG.

[Explanation of reference numerals] 1 fan-shaped conductor 1A end portion 20 connecting sleeves 21, 21A, 21B conductor insertion hole 22 central portion 22A small diameter cylindrical surface 23, 24 both end portions 23A, 24A large diameter cylindrical surface

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Atsushi Toya 1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Within Tokyo Electric Power Company (72) Inventor Shotaro Yoshida 1-1-5, Kiba, Koto-ku, Tokyo Fujikura (72) Inventor Masayuki Tan 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. (72) Inventor Watanabe 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Line Within the corporation

Claims (3)

[Claims] 1. A conductor insertion hole having a fan-shaped cross section is formed from both ends along the axial direction, and an outer peripheral surface of a central portion in the axial direction is a small diameter cylindrical surface, and both end portions adjacent to the central portion. A fan-shaped conductor connecting sleeve, wherein the outer peripheral surface of is a large-diameter cylindrical surface. 2. When connecting ends of fan-shaped conductors having a fan-shaped cross-section, the ends of the fan-shaped conductors are inserted into the conductor insertion holes of the connecting sleeve in which conductor insertion holes are formed from both ends. In the method of connecting a fan-shaped conductor to a fan-shaped conductor by compressing the sleeve from its outer peripheral side, the connecting sleeve has a fan-shaped cross section of the conductor insertion hole, and the outer peripheral surface of the central portion in the axial direction is A sleeve having a small-diameter cylindrical surface and the outer peripheral surfaces of both end portions adjacent to the central portion being large-diameter cylindrical surfaces is prepared, and after inserting the end portion of the fan-shaped conductor into the conductor insertion hole, a connecting sleeve A method for connecting a sleeve of a fan-shaped conductor, characterized in that the large-diameter cylindrical surface at both ends is compressed from the outer peripheral side until the diameter becomes equal to the outer diameter of the small-diameter cylindrical surface in the central portion. 3. When connecting the ends of fan-shaped conductors having a fan-shaped cross-section, the ends of the fan-shaped conductors are inserted into the conductor insertion holes of the connecting sleeve in which the conductor insertion holes are formed from both ends. In the method of connecting a fan-shaped conductor to a fan-shaped conductor by compressing the sleeve from its outer peripheral side, the connecting sleeve has a fan-shaped cross section of the conductor insertion hole, and the outer peripheral surface of the central portion in the axial direction is A sleeve having a small-diameter cylindrical surface and the outer peripheral surfaces of both end portions adjacent to the central portion being large-diameter cylindrical surfaces is prepared, and after inserting the end portion of the fan-shaped conductor into the conductor insertion hole, a connecting sleeve The small-diameter cylindrical surface of the central part is compressed from the outer peripheral side until the diameter reaches a predetermined finished diameter, and then the large-diameter cylindrical surfaces of both ends of the connecting sleeve are made to have the same diameter as the finished diameter of the central part. Sleeve connection sector conductors, which comprises compressing from the outer peripheral surface side until.