JP2010166639A - Manufacturing method of bushing insulator and terminal connection part of power cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain a waterproofing property for long time. <P>SOLUTION: A metallic conduit 32 is fitted in one end part of an insertion hole 31e and a bushing insulator body 31 is integrally molded in the metallic conduit 32 when molding the bushing insulator body 31 having the insertion hole 31e with an insulated rubber. Thus, the bushing insulator 30 is manufactured. A power cable 1 is inserted into the insertion hole 31e of the bushing insulator body 31, and a conductor pull-out bar 20 fitted to the tip of a conductor 2 of the power cable 1 is stored in the metallic conduit 32. Then, the metallic conduit 32 is riveted to its center so as to fasten the conductor pull-out bar 20 by the metallic conduit 32. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a cannula and a terminal connection part of a power cable, and more particularly to a method for manufacturing a cannula excellent in waterproofness and a terminal connection part of a power cable using the cannula manufactured by this method.

The end of the power cable is inserted into a tubular cannula, and the end of the power cable is mechanically protected or insulated by the cannula.
Conventional power cable termination sleeves include those made of porcelain (for example, see Patent Document 1) and those made of rubber (for example, see Patent Document 2).

  In the end portion of the power cable using the cannula, it is necessary to prevent water from entering the cannula. Therefore, for example, after the power cable is inserted into a rubber cannula, an insulating tape is wound around the end of the cannula to prevent moisture from entering (see Patent Document 2).

JP 2008-148418 A JP 2000-37027 A

However, it is difficult to maintain the waterproof performance for a long time even when the insulating tape is wound.
Therefore, a problem to be solved by the present invention is to be able to maintain waterproof performance for a long period of time.

  In order to solve the above problems, according to the present invention, there is provided a method for manufacturing a cannula used for a terminal connection portion of a power cable, which is made of a rubber having an insertion hole into which a power cable that has been stripped is inserted. When molding the cannula body, the cannula body is fitted to the end of the insertion hole so that a metal tube that houses a conductor lead bar attached to the tip of the conductor of the power cable is fitted into the metal tube. It was decided to be integrally molded with.

According to this manufacturing method, when the cannula body is molded, the cannula body is integrally formed with the metal tube, so that the waterstop between the cannula body and the metal tube is improved, and the waterstop is long. The period can be maintained.
Since the metal tube and the conductor extraction rod are made of metal, it is easy to make a structure having a water-stopping property between them.
Therefore, according to the manufacturing method of this cannula, the water stop of the edge part of the terminal connection part of an electric power cable can be improved, and the water stop can be maintained over a long period of time.

  In the manufacturing method, the metal tube may have a lid.

  If a lid is provided on the metal tube, it is difficult for water to enter the metal tube, and the waterproofness can be improved.

  In the manufacturing method, a small hole may be formed in the lid of the metal tube.

  If a small hole is formed in the lid of the metal tube, air in the cannula is discharged to the outside through the small hole when the end portion of the power cable is inserted into the cannula. Therefore, the power cable can be inserted into the sleeve to the end. That is, the conductor lead bar attached to the conductor of the cable can be steadily inserted until it comes into close contact with the lid of the metal tube. Further, since the inside of the metal tube can be looked through through the small hole, it can be confirmed whether or not the conductor lead-out rod has been steadily inserted into the metal tube to an appropriate position.

  The power cable terminal connecting portion according to the present invention is attached to the cannula manufactured by the manufacturing method and the tip of the conductor of the power cable inserted into the insertion hole of the cannula body, A conductor extraction rod housed in the metal tube, the metal tube is caulked toward the center, and the conductor extraction rod is tightened by the metal tube.

According to the terminal connection portion of this power cable, the conductor drawing rod is tightened by the metal tube by caulking the metal tube, so that the gap between the conductor drawing rod and the metal tube can be easily closed and water-proof, and waterproof. Performance can be improved. Moreover, since the metal tube is caulked, it is possible to maintain the tightening of the conductor lead bar for a long period of time, and to maintain a high waterproof performance for a long period of time.
Further, since the conductor lead bar is tightened by the metal tube by caulking the terminal metal tube of this power cable, it is easy to easily connect the metal tube and the conductor lead bar between the conductor lead bar and the metal tube. They can be connected electrically.

  Further, in the terminal connection portion of another power cable according to the present invention, a seal is provided between the conductor lead bar and the metal tube.

  According to the terminal connection portion of this power cable, the waterproof performance can be improved because the gap between the metal tube and the conductor lead bar is sealed by the seal.

  Further, in the terminal connection portion of another power cable according to the present invention, a metal tube provided with a lid having a small hole is used, and the conductor lead bar is inserted into the small hole of the metal tube. A fastening member to be fastened is provided.

According to the terminal connection portion of the power cable, water can be prevented from entering the metal tube through the small hole by inserting the fastening member into the small hole.
Moreover, since the conductor extraction rod and the metal tube are fastened by the fastening member, the conductor extraction rod is firmly fixed to the metal tube. Furthermore, it is possible to prevent water from entering between the conductor extraction rod and the metal tube lid by fastening the conductor extraction rod and the metal tube lid.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent more highly that water permeates into a cannula body, and the waterproof performance can be maintained over a long period of time.

It is the front view which showed the cannula in the state which made the cross section the half of the cannula used for the termination | terminus connection part of the electric power cable in 1st Embodiment of this invention. It is the front view which showed the termination | terminus connection part in the state which made the cross section the half of the termination | terminus connection parts of the power cable in the embodiment. It is drawing which expanded and showed the A area | region shown by FIG. It is the front view which showed the principal part of the termination | terminus connection part in the state which made the cross section the half of the termination | terminus connection parts of the electric power cable in 2nd Embodiment of this invention. It is the front view which showed the principal part of the termination | terminus connection part in the state which made the cross section the half of the termination | terminus connection parts of the power cable in other embodiment. It is the front view which showed the principal part of the termination | terminus connection part in the state which made the cross section the half of the termination | terminus connection parts of the power cable in the modification of other embodiment. It is the front view which showed the principal part of the termination | terminus connection part in the state which made the cross section the half of the termination | terminus connection part of the power cable in another modification of other embodiment.

  Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. However, the embodiments described below are given various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

[First Embodiment]
FIG. 1 is a front view showing a half of the plug-type cannula 30 in cross-section.
The cannula 30 has a substantially hollow cylindrical shape in which the cannula body 31, the metal tube 32, and the electric field relaxation part 33 are integrated.

The cannula body 31 is formed by tubular molding an insulating rubber material such as silicon rubber. The cannula body 31 includes a receiving portion 31a, a large diameter portion 31b, and a small diameter portion 31c. A receiving portion 31a is formed on one end side of the large diameter portion 31b along the axial direction, and the other end side of the large diameter portion 31b. A small-diameter portion 31c is formed on the surface. The outer diameter of the large diameter part 31b is larger than the outer diameters of the receiving part 31a and the small diameter part 31c. A plurality of shade portions 31d are formed on the outer peripheral surface of the small diameter portion 31c, and these shade portions 31d are arranged at predetermined intervals in the axial direction.
When the cannula body 31 is molded, the cannula body 31, the metal tube 32, and the electric field relaxation part 33 are integrated.

  The electric field relaxation part 33 is formed inside one end of the cannula body 31, and the outer peripheral side of the electric field relaxation part 33 is covered with the large diameter part 31 b and the receiving part 31 a of the cannula body 31. The electric field relaxation portion 33 is formed of a semiconductive resin obtained by adding carbon to rubber such as silicon rubber. The electric conductivity of the electric field relaxation portion 33 is higher than the electric conductivity of the sleeve main body 31.

  A portion of the electric field relaxation portion 33 covered with the large diameter portion 31b is a conical stress relief cone 33a, and a portion of the electric field relaxation portion 33 covered with the receiving portion 31a is a tube portion 33b. . The insertion hole 33c penetrates from the end of the tube portion 33b to the opposite side. The insertion hole 33c is smoothly connected to the insertion hole 31e of the cannula body 31.

  The metal tube 32 is fixed to the cannula body 31 in a state where the metal tube 32 is fitted into the opening of the end 31 g of the cannula body 31. The cannula body 31 and the metal tube 32 are fixed when the cannula body 31 is molded.

The metal tube 32 extends from the end 31 g of the cannula body 31 in the direction in which the axis of the cannula body 31 extends. Therefore, a part 32a of the metal tube 32 is covered with the end 31g of the cannula body 31, and the other part 32b is exposed. The inner diameter of the metal tube 32 is slightly smaller than the diameter of the insertion hole 31 e of the sleeve body 31.
The hole of the metal tube 32, the insertion hole 31e of the cannula body 31 and the insertion hole 33c of the electric field relaxation portion 33 are continuous, and the cannula 30 is formed in a generally hollow cylindrical shape as a whole.

Next, the manufacturing method of this cannula 30 is demonstrated.
First, the electric field relaxation part 33 and the metal tube 32 manufactured in advance are set in a mold. Next, when a fluid silicone rubber is injected into the mold and the silicone rubber is cured, the cannula body 31 is molded. In this way, the cannula body 31 is fitted so that the metal tube 32 fits into one end of the insertion hole 31e of the cannula body 31 and the electric field relaxation part 33 is wrapped around the other end of the cannula body 31. The electric field relaxation portion 33 and the metal tube 32 are fixed to the cannula body 31 by molding by the insert molding method. When insert molding is performed in this manner, the cannula body 31 closely adheres to the outer surface of the metal tube 32 and is difficult to peel off, so that the water blocking property and airtightness between the cannula body 31 and the metal tube 32 are improved.

  The termination connection part of the power cable using the sleeve 30 manufactured by the above method will be described. FIG. 2 is a front view showing a half of the terminal connection portion 10 of the power cable 1 in cross section, and FIG. 3 is an enlarged view of a portion A shown in FIG.

  First, the configuration of the termination connection unit 10 will be described. The terminal connection portion 10 includes a conductor lead bar 20 attached to the power cable 1 so as to extend from the end portion of the stepped power cable 1, and a sleeve 30 that receives the power cable 1 and the conductor lead bar 20. .

  The power cable 1 has a central conductor 2 covered with an insulator layer 3. The insulator layer 3 is covered with an external semiconductor layer 4, the external semiconductor layer 4 is covered with a protective corrugated metal tube 6, and the corrugated metal tube 6 is covered with a sheath 7. The terminal portion of the power cable 1 is stripped. That is, the sheath 7, the corrugated metal tube 6, the outer semiconductor layer 4, and the insulator layer 3 are sequentially exposed, and the conductor 2 is exposed at the tip.

  The conductor 2 of the power cable 1 is connected to one end portion (hereinafter referred to as “base end portion”) 22 of the conductor lead bar 20. The conductor lead bar 20 is a conductive metal bar. The conductor lead bar 20 is made of copper, aluminum, copper alloy, aluminum alloy or other metal. The diameter of the base end portion 22 of the conductor lead bar 20 is larger than the diameter of the other portion 23.

  A conductor insertion hole 21 is formed in the base end portion 22 of the conductor lead bar 20. The leading end portion of the conductor 2 of the power cable 1 is inserted into the conductor insertion hole 21 and the base end portion 22 of the conductor extraction rod 20 is compressed so that the diameter of the conductor insertion hole 21 is reduced. It is attached to the conductor 2.

  The power cable 1 and the conductor lead bar 20 are inserted into the sleeve 30. Specifically, the conductor lead bar 20 is inserted into the metal tube 32 with the end 24 (hereinafter referred to as the front end) opposite to the base end 22 first. Since the diameter of the base end portion 22 of the conductor lead bar 20 is larger than the inner diameter of the metal tube 32, the base end portion 22 closely contacts the end of the metal tube 32 in the sleeve body 31, and the other portion 23 is made of metal. The distal end portion 24 is exposed through the tube 32.

  The exposed portion 32b of the metal tube 32 is formed with one plastic deformation portion 32c that is caulked so as to be compressed toward the center (to be reduced in diameter), and one round in the circumferential direction. The plastic deformation portion 32c is rolled into a semicircular cross section by moving the round die in the circumferential direction while pressing firmly against the outer surface of the metal tube 32. By caulking the metal tube 32 over the entire circumferential direction, the conductor extraction rod 20 is tightened by the metal tube 32, and the gap between the metal tube 32 and the conductor extraction rod 20 is closed by the plastic deformation portion 32c. For this reason, the metal pipe 32 and the conductor lead bar 20 are in close contact with each other, and the water-tightness and airtightness are very high. Further, the metal tube 32 and the conductor lead bar 20 are electrically connected.

In the terminal connection portion 10, the diameter of the insertion hole 31 e of the sleeve main body 31 on the metal tube 32 side is set to the base end of the conductor lead bar 20 when the conductor lead bar 20 is not inserted into the sleeve main body 31. The diameter was smaller than the diameter of the portion 22. Therefore, the base end portion 22 of the inserted conductor lead bar 20 is tightened by the elastic force of the cannula main body 31, and water blocking and airtightness are also achieved between the base end portion 22 of the conductor lead bar 20 and the cannula main body 31. It is very high.
In addition, as described above, in the terminal connection portion 10, the diameter of the base end portion 22 of the conductor lead bar 20 is larger than the inner diameter of the metal tube 32, and the base end portion 22 abuts on the end of the metal tube 32. Therefore, even in this part, water-stopping and airtightness are increasing.

Next, the manufacturing method of the termination | terminus connection part 10 of this electric power cable 1 is demonstrated.
The terminal connection part 10 is manufactured at the installation location of the terminal part (mainly the air terminal part) of the power cable 1.
In addition to preparing the cannula 30 in which the metal tube 32 and the electric field relaxation part 33 are integrated with the cannula body 31 in advance, the conductor lead bar 20 is prepared. Then, the terminal portion of the power cable 1 is stripped, and the sheath 7, the corrugated metal tube 6, the external semiconductor layer 4, the insulator layer 3, and the conductor 2 are exposed in this order toward the tip.

  Next, the conductor 2 of the power cable 1 is inserted into the conductor insertion hole 21 of the conductor lead bar 20, and the base end portion 22 of the conductor lead bar 20 is compressed so as to reduce the diameter. As a result, the tip of the conductor 2 of the power cable 1 is attached to the conductor lead bar 20.

  Next, the conductor lead bar 20 is inserted into the insertion hole 33 c of the cannula 30 with the tip 24 of the conductor lead bar 20 first. Then, the conductor lead bar 20 is passed through the insertion hole 31 e, the conductor lead bar 20 is inserted into the metal tube 32, and the tip 24 of the conductor lead bar 20 is pulled out from the metal tube 32. When the conductor lead bar 20 is passed through the cannula 30, the power cable 1 is pulled by the conductor lead bar 20, and the power cable 1 is inserted into the insertion hole 33c and the insertion hole 31e. Before passing the conductor lead bar 20 through the cannula 30, the string or wire is connected to the distal end portion 24 of the conductor lead bar 20, the string or wire is passed through the cannula 30 from the insertion hole 33c, and the string or wire is connected. The conductor pulling bar 20 may be guided to the metal tube 32 by pulling toward the metal tube 32 side. In this case, after the conductor lead bar 20 is housed in the metal tube 32, the string or wire is removed from the conductor lead bar 20.

  The conductor extraction rod 20 drawn from the metal tube 32 is pulled, and the base end portion 22 of the conductor extraction rod 20 is brought into contact with the end of the metal tube 32 to be locked.

  Next, the exposed portion 32b of the metal tube 32 is crimped toward the center to form the plastic deformation portion 32c over the entire circumferential direction of the exposed portion 32b. As a result, the plastic deformation portion 32 c is pressed against the conductor lead bar 20. By tightening the conductor lead bar 20 with the metal tube 32 in this manner, the conductor lead bar 20 and the metal tube 32 can be brought into close contact with each other and electrical conduction therebetween can be obtained.

  As described above, according to this embodiment, since the metal tube 32 is fixed to the cannula body 31 when the cannula body 31 is molded, there is no gap at the interface between the cannula body 31 and the metal tube 32. . By caulking the metal tube 32, the conductor lead bar 20 is tightened by the metal tube 32, so that the conductor lead bar 20 is not easily detached from the metal tube 32 and water can be prevented from entering the sleeve body 31. Can do.

  In addition, since the plastic deformation portion 32c is formed by caulking the metal tube 32, the tightening of the conductor lead bar 20 can be maintained for a long period of time. Therefore, the waterproof performance can be maintained for a long time.

  In addition, the power cable 1 is not tightened by caulking the metal tube 32, but the conductor lead bar 20 is tightened. Therefore, damage to the power cable 1 can be prevented.

  Further, since the portion of the metal tube 32 that extends from the end 31g of the cannula body 31 is caulked, the cannula body 31 does not peel off from the metal tube 32 during caulking.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIG. Here, the same code | symbol is attached | subjected to the part similar to 1st Embodiment.

  4, an O-ring seal 41 is sandwiched between the inner surface of the metal tube 32 and the outer peripheral surface of the conductor lead bar 20. The seal 41 is made of an elastomer such as rubber. In FIG. 4, two seals 41 are sandwiched between the conductor lead bar 20 and the metal tube 32, but the number of the seals 41 may be one or two or more.

  Since the seal 41 is sandwiched between the conductor lead bar 20 and the metal tube 32 in this way, the waterproof property is high.

The manufacturing method of the cannula 30 is the same as that in the first embodiment.
In manufacturing the terminal connection part 10, the seal 41 is fitted into the conductor lead bar 20 before the conductor lead bar 20 is inserted into the metal tube 32. Thereafter, similarly to the case of the first embodiment, the conductor lead bar 20 is inserted into the metal tube 32 together with the seal 41, and the metal tube 32 is caulked. Alternatively, the conductor lead bar 20 may be inserted into the metal tube 32 after the seal 41 is disposed in the metal tube 32.

  Except as described above, the second embodiment is the same as the first embodiment. Note that the metal tube 32 need not be caulked if the seal 41 can sufficiently ensure water-tightness and airtightness.

[Other Embodiments]
Another embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals.

  5 is longer than that of the first embodiment, and a lid 32d is formed at the end of the metal tube 32 extending from the cannula main body 31. As shown in FIG. A small hole 32e passes through the center of the lid 32d. The manufacturing method of the cannula 30 is the same as that of the first embodiment except that the metal tube 32 having the lid 32d is used.

  In the terminal connection portion 10 using the cannula 30, the tip 24 of the conductor lead bar 20 is covered with a metal tube 32, and the end surface of the tip 24 is in contact with the lid 32d. Since the lid 32d is formed at the end of the metal tube 32, the waterproof property is further enhanced.

  A small hole 32e formed in the lid 32d of the metal tube 32 is used for releasing air. That is, when the terminal connection part 10 is manufactured, when the power cable 1 is inserted into the cannula 30, the air inside is also released from the small hole 32e. Therefore, the conductor lead bar 20 can be inserted until the tip 24 of the conductor lead bar 20 is brought into contact with the lid 32d of the metal tube 32.

  Further, when the conductor lead bar 20 is inserted into the metal tube 32, the inside of the metal tube 32 can be seen through the small hole 32e. Therefore, it can be confirmed whether or not the conductor lead bar 20 has been steadily inserted into the metal tube 32.

  When the power cable 1 is inserted into the sleeve 30, a wire is connected to the conductor lead bar 20, this wire is drawn out through the small hole 32 e, and the power cable 1 and the conductor lead bar 20 are connected with the wire. Can be towed.

  The terminal connection portion 10 shown in FIG. 6 uses a metal tube 32 provided with a lid 32d, and, similarly to the second embodiment, between the inner surface of the metal tube 32 and the outer peripheral surface of the conductor lead bar 20. The seal 41 is disposed on the surface. By doing so, waterproofness is further improved.

  In the terminal connection portion 10 shown in FIG. 7, a fastening bolt 42 is passed through the small hole 32 e of the metal tube 32, and the fastening bolt 42 is screwed to the tip end portion 24 of the conductor drawing rod 20, whereby the conductor drawing rod 20 The distal end portion 24 and the lid 32d of the metal tube 32 are fastened. Since the small hole 32e is closed by the head of the fastening bolt 42, the waterproof property is further improved.

In the case of using the fastening bolt 42, after inserting the conductor lead bar 20 into the metal tube 32, the fastening bolt 42 is passed through the small hole 32 e and the fastening bolt 42 is screwed into the distal end portion 24 of the conductor lead bar 20. As a result, the distal end portion 24 of the conductor lead bar 20 is fastened to the lid 32d of the metal tube 32, so that the waterproofness is further improved.
Here, the screw hole in which the fastening bolt 42 is stopped is formed in advance on the end face of the distal end portion 24 of the conductor lead bar 20 before the conductor lead bar 20 is inserted into the metal tube 32. Of course, after inserting the conductor lead bar 20 into the metal tube 32, a screw hole may be formed on the end face of the end face 24 of the conductor lead bar 20 through a small hole 32e.

  Except as described above, the third embodiment is the same as the first embodiment.

The present invention is not limited to the above embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.
For example, in the case of FIG. 5 or FIG. 6, the small hole 32e may not be formed. If the small hole 32e is not formed, the end portion of the metal tube 32 is completely closed, so that the waterproof property is higher than when the small hole 32e is provided.

In the case of FIG. 7, the seal 41 may not be provided.
Further, in the case of FIGS. 6 and 7, the metal tube 32 may not be caulked if the seal 41 can sufficiently ensure water-tightness and airtightness.
Further, in the case of FIG. 7, what fastens the distal end portion 24 of the conductor lead bar 20 and the lid 32 d of the metal tube 32 is not limited to a bolt, and may be a rivet, a screw or other fastening member. For example, in the case of a rivet, a rivet shaft is provided in a state where the end portion 24 of the leading end portion 24 of the conductor pulling bar 20 is set up in advance. Then, crush the rivet shaft. By doing so, the distal end portion 24 of the conductor lead bar 20 and the lid 32d of the metal tube 32 are fastened.

  Moreover, in the said embodiment, although the part extended from the edge part 31g of the cannula body 31 among the metal pipes 32 is crimped, the diameter of the metal tube 32 is reduced from above the end part 31g of the cannula body 31. It may be caulked.

DESCRIPTION OF SYMBOLS 1 Electric power cable 2 Conductor 10 Termination connection part 20 Conductor extraction rod 30 Tubular tube 31 Tubular body 31e Insertion hole 33c Insertion hole 32 Metal tube 32d Lid 32e Small hole 33 Electric field relaxation part 41 Seal 42 Fastening bolt

Claims (6)

A method of manufacturing a cannula used for a terminal connection part of a power cable,
When molding a rubber cannula body having an insertion hole into which a stepped power cable is inserted, a metal tube in which a conductor extraction rod attached to the tip of a conductor of the power cable is stored is inserted. A method for manufacturing a cannula, wherein the cannula body is integrally formed with the metal tube so as to be fitted to one end of a hole.   The method for manufacturing a cannula according to claim 1, wherein the metal tube has a lid.   The method for manufacturing a cannula according to claim 2, wherein a small hole is formed in the lid of the metal tube. A sleeve manufactured by the manufacturing method according to any one of claims 1 to 3,
A conductor lead bar attached to the tip of the conductor of the power cable inserted into the insertion hole of the sleeve body, and housed in the metal tube;
An end connection portion of a power cable, wherein the metal tube is caulked toward the center thereof, and the conductor lead bar is fastened by the metal tube. A sleeve manufactured by the manufacturing method according to any one of claims 1 to 3,
A conductor extraction rod attached to the tip of the conductor of the power cable inserted into the insertion hole of the sleeve body, and housed in the metal tube;
An end connection part of a power cable, comprising: a seal provided between the conductor lead bar and the metal tube. A sleeve manufactured by the manufacturing method according to claim 3;
A conductor extraction rod attached to the tip of the conductor of the power cable inserted into the insertion hole of the sleeve body, and housed in the metal tube;
And a fastening member that is inserted into the small hole and fastens the conductor lead bar to the lid of the metal tube.

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