JPH1032910A - Method for enlarging diameter of premolded rubber insulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the increase of the number and lengths of internal defects and the developing of cracks in the rubber of a premolded rubber insulator by enlarging the diameter of the insulator by inserting a diameter enlarging jig having a smaller outer diameter into the insulator from the smaller inner diameter side, and another diameter enlarging jig having a larger outer diameter into the insulator from the larger inner diameter side, when the inner diameter of the insulator is different between the left and right sides. SOLUTION: The inner diameter of a premolded insulator 2 is enlarged by inserting a diameter enlarging jig 30 having a smaller outer diameter into the insulator 2 from the smaller diameter side, while a tapered inserting jig 31 is attached to the front end of the jig 30. When the jig 30 is inserted into the insulator 2, the jig 31 is removed after the jig 30 is inserted to a prescribed position so that the jig 30 can be inserted smoothly. Then, the inner diameter of the larger inner diameter side of the insulator 2 is enlarged, by inserting another diameter enlarging jig 32 having a larger outer diameter and a tapered section 32a at its front end into the insulator 2 from the larger inner diameter side, until the front end of the jig 32 can come into contact with the stepped portion of an internal electrode 22. Therefore, the increase of the number and lengths of internal defects and the occurrence of cracks in the insulator 2 can be suppressed, because the diameter enlarging ratio of the small-diameter side of the insulator 2 can be reduced.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、特に内径が左右異
なるプレモールドゴム絶縁体の拡径方法に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for expanding a diameter of a pre-molded rubber insulator having different inner diameters.

【０００２】[0002]

【従来の技術】図３は接続する左右のケーブルの外径が
異なるＣＶケーブル等のプラスチック電力ケーブル接続
部の要部の縦断面図である。図面において、１Ａは小径
ケーブル、１Ｂは大径ケーブルであって、１１Ａ、１１
Ｂは塩化ビニル、ポリエチレン等のケーブルシース、１
２Ａ、１２Ｂは架橋ポリエチレン等のプラスチック絶縁
体を具えたケーブルの絶縁コア、１３は導体接続部であ
る。２は絶縁ゴム部２１の内周部に半導電性ゴムの内部
電極２２を、外周部に半導電性ゴムの外部半導電層２３
をあらかじめ一体成形したプレモールドゴム絶縁体で、
その内径はその部分に挿入されるそれぞれの絶縁コア１
２Ａ、１２Ｂの外径より小さく形成されており、上記内
部電極２２は長さ方向の中央部付近で内径を変え、絶縁
ゴム部２１及び外部半導電層２３は左右の内径が異なる
構造である。2. Description of the Related Art FIG. 3 is a longitudinal sectional view of a main part of a plastic power cable connecting portion such as a CV cable having different outer diameters of right and left cables to be connected. In the drawings, 1A is a small-diameter cable, 1B is a large-diameter cable,
B is a cable sheath of vinyl chloride, polyethylene, etc., 1
2A and 12B are insulating cores of a cable provided with a plastic insulator such as cross-linked polyethylene, and 13 is a conductor connecting portion. Reference numeral 2 denotes a semiconductive rubber internal electrode 22 on the inner peripheral portion of the insulating rubber portion 21 and an outer semiconductive layer 23 of semiconductive rubber on the outer peripheral portion.
Is a pre-molded rubber insulator that is integrally molded in advance,
The inner diameter of each insulating core 1 inserted into that part
The inner electrodes 22 are formed smaller than the outer diameters of the inner electrodes 2A and 12B. The inner electrodes 22 have inner diameters changed near the center in the length direction, and the insulating rubber portion 21 and the outer semiconductive layer 23 have different left and right inner diameters.

【０００３】接続部の形成にあたっては、上記プレモー
ルドゴム絶縁体２の内径部に１本物の拡径治具を挿入し
て拡径し、ケーブル導体の接続前にあらかじめ一方のケ
ーブルシース上に挿通しておき、ケーブル導体の接続後
に上記プレモールドゴム絶縁体２を導体接続部１３上に
戻し、上記拡径治具を引抜くことによりプレモールドゴ
ム絶縁体２の弾性力による自己収縮力により絶縁コア１
２上に密着して装着され、接続部絶縁体が形成される。
上記プレモールドゴム絶縁体２の外側には外部ケース３
が施され、その両端はケーブルシース１１上に位置せし
め気密にシールする。[0003] In forming the connection portion, a single diameter expanding jig is inserted into the inner diameter portion of the pre-molded rubber insulator 2 to increase the diameter, and the jig is inserted into one of the cable sheaths before connecting the cable conductor. After the cable conductor is connected, the pre-molded rubber insulator 2 is returned onto the conductor connection portion 13 and the diameter-expanding jig is pulled out to insulate the pre-molded rubber insulator 2 by the self-shrinkage force of the elastic force of the pre-molded rubber insulator 2. Core 1
2 are closely attached to each other to form a connection portion insulator.
An outer case 3 is provided outside the pre-molded rubber insulator 2.
The two ends are positioned on the cable sheath 11 and hermetically sealed.

【０００４】[0004]

【発明が解決しようとする課題】上述したケーブル外径
が異なるケーブル接続部の形成における従来のプレモー
ルドゴム絶縁体の拡径方法は、１本物の拡径治具をプレ
モールドゴム絶縁体の内径部の一端から挿入して拡径
し、導体接続前にあらかじめ一方のケーブルシース上に
逃がしておく必要があるため、プレモールドゴム絶縁体
を最終形状よりもさらに大きく拡径する必要があり、特
に絶縁体外径大側のケーブル絶縁体外径が小側のシース
外径よりも大きい場合は、さらに大きく拡径する必要が
ある。しかしこのような場合、プレモールドゴム絶縁体
のゴム内部欠陥を増長させるおそれがある。又拡径治具
はプレモールドゴム絶縁体の一方向から挿入し、一方向
に引抜くため、拡径治具の逃がし代を長くとる必要があ
り、狭いスペース内での組立には適さないという問題が
ある。The conventional method for expanding the diameter of the pre-molded rubber insulator in forming the cable connection portions having different cable outer diameters as described above uses a single diameter-expanding jig and the inner diameter of the pre-molded rubber insulator. Since it is necessary to insert from one end of the part and expand the diameter and release it on one cable sheath in advance before connecting the conductor, it is necessary to expand the diameter of the pre-molded rubber insulator larger than the final shape, especially If the outer diameter of the cable insulator on the larger side of the insulator is larger than the outer diameter of the sheath on the smaller side, it is necessary to increase the diameter further. However, in such a case, the internal rubber defects of the pre-molded rubber insulator may be increased. Also, since the expanding jig is inserted from one direction of the pre-mold rubber insulator and pulled out in one direction, it is necessary to take a long allowance for the expanding jig, which is not suitable for assembly in a narrow space. There's a problem.

【０００５】[0005]

【課題を解決するための手段】本発明はプレモールドゴ
ム絶縁体の拡径率を小さくするとともに、拡径治具の逃
がし代を短くしたプレモールドゴム絶縁体の拡径方法を
提供するもので、その特徴は、プレモールドゴム絶縁体
の左右の内径が異なる場合において、まず内径小側から
外径小の拡径治具をその先端にテーパ状の挿入治具を装
着して挿入し、ついで内径大側から先端にテーパ部を形
成した大径の拡径治具を挿入して拡径することにある。SUMMARY OF THE INVENTION The present invention provides a method of expanding the diameter of a pre-molded rubber insulator in which the diameter of the pre-molded rubber insulator is reduced and the escape allowance of the diameter-expanding jig is shortened. The feature is that when the left and right inner diameters of the pre-molded rubber insulator are different, first insert the tapered insertion jig from the small inner diameter side with the tapered insertion jig at the tip, then insert. An object of the present invention is to insert a large-diameter expanding jig having a tapered portion at the tip from the large inner diameter side to expand the diameter.

【０００６】[0006]

【発明の実施の形態】図１は本発明拡径方法の具体例の
縦断面をあらわした説明図である。図面に示すように、
まずプレモールドゴム絶縁体２の内径小側（図の左側）
から小外径の拡径治具３０を、その先端にテーパ状の挿
入治具３１を装着して挿入し内径側を拡径する。この
際、上記テーパ状の挿入治具３１は大外径の拡径治具３
０の挿入に支障がないように、小外径拡径治具３０を所
定の位置に挿入した後除去する。つづいて内径大側（図
の右側）から先端にテーパ部３２ａを形成した大外径の
拡径治具３２を、その先端が内部電極２２の段差部に接
する位置まで挿入して内径大側を拡径する。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing a longitudinal section of a specific example of the diameter expanding method of the present invention. As shown in the drawing,
First, the small inner diameter side of the pre-mold rubber insulator 2 (left side in the figure)
Then, a taper-shaped insertion jig 31 is attached to the tip of the jig 30 having a small outer diameter, and the jig is inserted to expand the inner diameter side. At this time, the tapered insertion jig 31 is a large-diameter expanding jig 3.
The jig 30 is removed after the jig 30 is inserted into a predetermined position so as not to hinder the insertion of the zero. Subsequently, a large-diameter expanding jig 32 having a tapered portion 32a formed at the tip from the large-diameter side (right side in the drawing) is inserted until the tip thereof comes into contact with the step portion of the internal electrode 22, and the large-diameter side is inserted. Expand the diameter.

【０００７】このように、プレモールドゴム絶縁体２の
内径小側から小外径の拡径治具３０を、内径大側から大
外径の拡径治具３２を挿入することにより、プレモール
ドゴム絶縁体２の小径側の拡径率を小さくすることがで
き、プレモールドゴム絶縁体２に過大な応力が加わるこ
とがなく、ゴムの内部欠陥の増長や割れの発生を抑制す
ることができる。又拡径治具の取外しに際しては、拡径
治具をプレモールドゴム絶縁体２の両側に逃がすため、
拡径治具の逃がし代を短くすることができ、狭いスペー
スでの組立にも効果的である。As described above, the pre-mold rubber insulator 2 is inserted into the small-diameter expanding jig 30 from the small inner side and the large-diameter expanding jig 32 from the large inner side to the pre-molded rubber insulator 2. The rate of expansion of the rubber insulator 2 on the small diameter side can be reduced, so that excessive stress is not applied to the pre-molded rubber insulator 2, and it is possible to suppress the increase of internal defects of the rubber and the occurrence of cracks. . Also, when removing the expanding jig, in order to escape the expanding jig to both sides of the pre-molded rubber insulator 2,
The escape allowance of the expanding jig can be shortened, which is effective for assembling in a narrow space.

【０００８】図２は本発明拡径方法の他の具体例の縦断
面をあらわした説明図である。プレモールドゴム絶縁体
２の左右の内径の差が小さい場合には、図面に示すよう
に、まず内径小側から先端にテーパ状挿入治具３１を取
付けた小外径の拡径治具３０を挿入して内径小側を拡径
した後、上記挿入治具３１を取外す。そして、内径大側
から先端にテーパ部３２ａを形成した大外径の拡径治具
３２をその先端が小外径拡径治具３０の先端近くまで挿
入して内径大側を拡径する。FIG. 2 is an explanatory view showing a longitudinal section of another embodiment of the diameter expanding method of the present invention. When the difference between the left and right inner diameters of the pre-mold rubber insulator 2 is small, as shown in the drawing, first, a small outer diameter expanding jig 30 having a tapered insertion jig 31 attached to the tip from the small inner diameter side is used. After the insertion, the diameter of the small inner diameter side is expanded, and the insertion jig 31 is removed. Then, a large-diameter expanding jig 32 having a tapered portion 32a formed at the front end from the large-diameter side is inserted near the front end of the small-diameter expanding jig 30 at the front end to expand the large-diameter side.

【０００９】[0009]

【発明の効果】以上説明したように、本発明のプレモー
ルドゴム絶縁体の左右の内径が異なる場合、内径小側か
ら小外径拡径治具を内径大側から大外径拡径治具を挿入
してプレモールドゴム絶縁体を拡径することにより、プ
レモールドゴム絶縁体の拡径率を小さくすることがで
き、ゴムの内部欠陥の増長や割れの発生を抑止すること
ができる。又拡径治具の取外しに際しては、拡径治具を
プレモールドゴム絶縁体の両側に逃がすため、拡径治具
の逃がし代を短くすることができ、狭いスペースでの組
立に効果的である。従って、接続する左右のケーブル外
径が異なるＣＶケーブル等のプラスチック電力ケーブル
の差込式接続部の形成に利用するとき、極めて効果的で
ある。As described above, when the left and right inner diameters of the pre-molded rubber insulator of the present invention are different, the jig with the smaller outer diameter from the smaller inner diameter side and the jig with the larger outer diameter from the larger inner diameter side. The diameter of the pre-molded rubber insulator can be reduced by inserting the pre-molded rubber insulator to reduce the diameter expansion rate of the pre-molded rubber insulator, thereby suppressing an increase in internal defects of the rubber and the occurrence of cracks. Also, when removing the diameter-expanding jig, the diameter-expanding jig is made to escape to both sides of the pre-molded rubber insulator, so that the escape margin of the diameter-expanding jig can be shortened, which is effective for assembling in a narrow space. . Therefore, it is very effective when used for forming a plug-in connection portion of a plastic power cable such as a CV cable having different outer diameters of left and right cables to be connected.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明拡径方法の具体例の縦断面をあらわした
説明図である。FIG. 1 is an explanatory view showing a longitudinal section of a specific example of the diameter expanding method of the present invention.

【図２】本発明拡径方法の他の具体例の縦断面をあらわ
した説明図である。FIG. 2 is an explanatory view showing a longitudinal section of another specific example of the diameter expanding method of the present invention.

【図３】接続する左右のケーブル外径が異なるプラスチ
ック電力ケーブル接続部の要部の縦断面図である。FIG. 3 is a vertical cross-sectional view of a main part of a plastic power cable connecting portion having different outer diameters of left and right cables to be connected.

【符号の説明】[Explanation of symbols]

２ プレモールドゴム絶縁体 21 絶縁ゴム部 22 内部電極 23 外部半導電層 30 小径拡径治具 31 テーパ状挿入治具 32 大径拡径治具 32ａ 先端テーパ部 2 Pre-molded rubber insulator 21 Insulated rubber part 22 Internal electrode 23 External semiconductive layer 30 Small diameter expanding jig 31 Tapered insertion jig 32 Large diameter expanding jig 32a Tapered end

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 あらかじめ一体成形した絶縁ゴム部と半
導電性ゴム部からなるプレモールドゴム絶縁体の内径部
に、拡径治具を挿入してその内径を拡径する方法であっ
て、上記プレモールドゴム絶縁体の左右の内径が異なる
場合において、まず内径小側から外径小の拡径治具をそ
の先端にテーパ状の挿入治具を装着して挿入し、ついで
内径大側から先端にテーパ部を形成した大径の拡径治具
を挿入して拡径することを特徴とするプレモールドゴム
絶縁体の拡径方法。1. A method for inserting a diameter increasing jig into an inner diameter portion of a pre-molded rubber insulator composed of an insulating rubber portion and a semiconductive rubber portion which are integrally formed in advance and expanding the inner diameter. When the inner diameter of the left and right sides of the pre-molded rubber insulator is different, first insert a jig with a small outer diameter from the smaller inner diameter side by attaching a tapered insertion jig to its tip, and then insert the tip from the larger inner diameter side. A method for expanding the diameter of a pre-molded rubber insulator, comprising inserting a large-diameter expanding jig having a tapered portion into the outer periphery thereof to increase the diameter.