JP4002127B2

JP4002127B2 - Cable connection processing method

Info

Publication number: JP4002127B2
Application number: JP2002085236A
Authority: JP
Inventors: 大介武藤
Original assignee: Furukawa Electric Co Ltd
Current assignee: Furukawa Electric Co Ltd
Priority date: 2002-03-26
Filing date: 2002-03-26
Publication date: 2007-10-31
Anticipated expiration: 2022-03-26
Also published as: JP2003284232A

Description

【０００１】
【発明の属する技術分野】
本発明は常温収縮型の電力ケーブルの接続部を組み立てる場合のケーブル接続処理方法に関するものである。
【０００２】
【従来の技術】
近年、電力ケーブルの中間接続部等の施工性を向上させるために、拡径支持筒の外周に常温収縮型のゴム絶縁筒を拡径状態で支持してなるゴムユニットが使用されるようになってきている。このゴム絶縁筒はシリコーンゴムやＥＰゴム等の弾性を有する常温収縮材料で構成され、内部半導電層、外部半導電層、ストレスコーン層及び補強絶縁層が一体成形されたものである。この種のゴム絶縁筒を用いた常温収縮型接続部は、常温収縮材料の弾性力により接続界面圧力を発生させ、界面電気性能を保つ設計となっており、ゴム絶縁筒の内径はケーブル絶縁体の外径よりも細く形成されている。
【０００３】
この常温収縮型接続部は部品数が少なく接続処理が簡単であること、組立時の品質管理が容易であること等の特徴を有している。一般に常温収縮型接続部はゴム製のワンピース型であるので、組立時の品質管理のポイントはケーブル絶縁体とゴム絶縁筒の界面状態、即ち、突起、傷、異物や両者の密着状態等である。界面の状態が悪いと、接続部の電気性能を著しく低下させる原因となる。
【０００４】
ワンピース型のゴム絶縁筒は工場、あるいは、組立現場において、予めその内径を電力ケーブルのケーブルシース外径よりも大きく広げ、円筒状の拡径支持筒の外周に拡径状態で支持する。前者の拡径方式を工場拡径方式、後者の拡径方式を現場拡径方式と称している。拡径支持筒は一般的にポリプロピレン等のプラスチック製の紐状体を螺旋状に巻回して円筒状に形成したもの、あるいは、円形の剛性金属筒（剛性金属管）で構成される。
【０００５】
前記紐状体を螺旋状に巻回して形成された拡径支持筒の外周にゴム絶縁筒を拡径状態で支持してなるゴムユニットを用いたケーブル接続処理方法を、図６、７により説明する。先ず、電力ケーブル１、１の接続すべき各端末を段剥ぎしてケーブルシース９の段剥ぎ切断端から遮水金属層８、遮蔽層７、導電性布テープ巻層６、外部半導電層５、ケーブル絶縁体４及び導体口出部３を順次段剥ぎすることにより段剥ぎ端部２を形成する。次に、遮蔽層７を構成するシールドワイヤ７Ａをケーブルシース９側へ折り返し、その折り返し部７Ｂをケーブルシース９の上に配置する。次に、紐状体１２を螺旋状に巻回して円筒状に形成された拡径支持筒１１の外周にゴム絶縁筒１３を拡径状態で支持してなるゴムユニット１０を、導体接続前に、電力ケーブル１、１の一方の段剥ぎ端部３、例えば、図７に示すように、右側の段剥ぎ端部２からケーブルシース９側に予め通しておく。次に、両段剥ぎ端部２、２の導体口出部３同士を導体接続して導体接続部１４を形成する。
【０００６】
このようにして、電力ケーブル１、１の導体接続後、ゴムユニット１０を、図６に示すように、前記ケーブルシース９側から両段剥ぎ端部２、２側、即ち、導体接続部１４の上に移動させる。次に、拡径支持筒１１を構成する紐状体１２を拡径支持筒１１の右端１１Ａ側から拡径支持筒１１の内側に通して図６の左側に引く抜き、ゴム絶縁筒１３を所定の位置に合わせながら拡径支持筒１１をその右端１１Ａから順次解体して除去する。これに伴って、ゴム絶縁筒１３をその右端１３Ａから順次縮径して行き、段剥ぎ端部２、２の外周に、即ち、導体接続部１４、ケーブル絶縁体４、４の外周に、外部半導電層５、５に跨るようにして装着することにより常温収縮型接続部を組み立てる。なお、ゴムユニット１０の拡径支持筒１１として剛性金属筒を用いる場合には、ゴム絶縁筒１３を縮径するために、剛性金属筒を専用工具で引き抜いて除去する以外は前記接続処理方法と同様である。
【０００７】
【発明が解決しようとする課題】
常温収縮型接続部を組み立てる場合のケーブル接続処理方法においては、工場拡径方式又は現場拡径方式いずれの場合にも、予めゴム絶縁筒１３を備えたゴムユニット１０を一方のケーブルシース９側に通しておく必要があるため、ゴム絶縁筒１３の内径を、前記ケーブルシース９の外径に、少なくとも拡径支持筒１１の肉厚の２倍に相当する分をプラスした大きさだけ広げる必要がある。
【０００８】
また、電力ケーブル１の遮蔽層７がシールドワイヤ７Ａで構成されているものを接続する場合には、図７に示すように、シールドワイヤ７Ａの折り返し部７Ｂをケーブルシース９の上に配置する必要があるため、シールドワイヤ７Ａの外径×２倍に相当する分だけより大きく広げる必要がある。具体的に説明すると、シールドワイヤ７Ａは一般的に外径が１．２ｍｍφであるので、シールドワイヤ７Ａの折り返し部７Ｂがケーブルシース９の上に配置されると、ゴム絶縁筒１３の内径は少なくとも２．４ｍｍφだけより大きく広げる必要がある。実際には、折り返し部７Ｂの根元が図７に示すように膨らむため、４〜５ｍｍだけ余分に広げることが必要になる。
【０００９】
ゴム絶縁筒１３が拡径により伸ばされた状態で長時間が経過すると、常温収縮材料の永久伸び量が大きくなり、弾性力が低下する。そうすると、ゴム絶縁筒１３を前記段剥ぎ端部２の外周に装着時の界面面圧が低下するため、常温収縮型接続部の界面電気性能が低下する恐れがある。
【００１０】
ゴム絶縁筒１３を設計する際には、このような拡径時の永久伸び量を考慮してゴム絶縁筒１３の内径をより小さくし、ゴム絶縁筒１３の装着時の界面面圧を大きくすることも考えられる。しかし、その場合には、拡径支持筒１１に加わる外圧力が増大するため、拡径支持筒１１の外周にゴム絶縁筒１３を拡径状態で支持したり、拡径支持筒１１を解体又は引き抜きにより除去したりするのが困難で、施工性が悪くなることやゴムユニット１０の保管や組立中に拡径支持筒１１が崩壊する恐れがある。
【００１１】
一方、図８に示すように、遮蔽層７を構成するシールドワイヤ７Ａを前記のように折り返すことなく、段剥ぎ端部２のケーブル絶縁体４の外表面に沿わせておくことも考えられる。この場合には、ゴムユニット１０の拡径支持筒１１の内径、即ち、ゴム絶縁筒１３の内径を小さくすることができるが、ニッパ等でシールドワイヤ７Ａを所定の長さに切断した場合に、その先端の切断面７Ｃが非常に鋭利なので、これがケーブル絶縁体４の外表面に接触して該絶縁体４の外表面を傷付け易く、常温収縮型接続部の界面電気性能を低下させる原因となる。
【００１２】
また、その対策として、前記ケーブル絶縁体４の外周に傷防止のための保護テープを巻くことも考えられるが、施工上、最も重要な品質管理のポイントとなるケーブル絶縁体等の外表面に保護テープの微小断片や接着剤等の異物が付着し易く好ましくない。
【００１３】
ゴム絶縁筒１３の永久伸び量は常温収縮材料の伸張率（伸びの大きさ）と伸びが作用している期間に依存する。このため、できるだけ、ゴム絶縁筒１３の伸張率を小さくし、且つ、ゴム絶縁筒１３の拡径支持時間を短くすることが望ましい。しかしながら、後者の拡径支持時間を短くするためには、ゴム絶縁筒１３を工場拡径方式で拡径支持筒１１の外周に支持する場合、ゴムユニット１０の工場出荷からケーブル接続処理に使用するまでの期間を短くしなければならない制約が付く。また、ゴム絶縁筒１３を現場拡径方式で拡径支持筒１１の外周に支持する場合には、前者よりも作業環境及び設備の十分整備されていない現場で、ゴム絶縁筒１３の拡径支持筒１１への支持及び段剥ぎ端部２への装着を短時間で完了しなければならないという制約が付き、施工作業に少なからず支障をきたす。このため、ゴム絶縁筒１３の拡径支持時間を短縮することは容易でない。
【００１４】
本発明は上記の課題を解決するためになされたもので、ゴムユニットの拡径支持筒にゴム絶縁筒を拡径状態で支持する際、ゴム絶縁筒を構成する常温収縮材料の伸張率を小さくして、ゴム絶縁筒の拡径支持期間中における常温収縮材料の永久伸び量を小さくし、ゴム絶縁筒の段剥ぎ端部への装着時の界面面圧を大きくして、常温収縮型接続部の界面電気性能を向上させると共に、従来の接続部組立の施工性と品質管理の容易さを損なうことのないケーブル接続処理方法を提供する。
【００１５】
【課題を解決するための手段】
上記課題を解決する本発明の請求項１記載のケーブル接続処理方法は、拡径支持筒の外周に常温収縮型のゴム絶縁筒を拡径状態で支持してなるゴムユニットを遮蔽層がシールドワイヤで構成される電力ケーブルの一方のケーブルシース側に予め通しておき、導体接続後、ゴムユニットを前記ケーブルシース側から電力ケーブルの両段剥ぎ端部側に移動させ、ゴムユニットの拡径支持筒を除去することによりゴム絶縁筒を縮径して両段剥ぎ端部の外周に装着するようにしたケーブル接続処理方法において、遅くともゴムユニットを前記ケーブルシース側から両段剥ぎ端部側に移動させる前に、両段剥ぎ端部から露出された遮蔽層を構成するシールドワイヤを、ケーブル絶縁体とケーブルシース間で折り返して折り返し部を形成し、その折り返し部を両者間の段剥ぎ端部の上に配置しておくことにより、前記拡径支持筒の内径をケーブルシース外径に対し１ｍｍ程度の増加で抑えられ、常温収縮型のゴム絶縁筒の常温収縮材料の永久伸び量を小さくするとともに、前記常温収縮型のゴム絶縁筒の装着時の界面面圧を大きくしたことを特徴とするケーブル接続処理方法である。
【００１６】
上記構成により、遮蔽層を構成するシールドワイヤの折り返し部をケーブルシースの上に配置しなくて済むので、ゴムユニットの拡径支持筒の内径をケーブルシース外径＋１ｍｍ程度の大きさに縮径でき、拡径支持筒の外周に拡径状態で支持するゴム絶縁筒の内径を従来のものより少なくとも４〜５ｍｍ小さくすることが可能である。これにより、ゴム絶縁筒を構成する常温収縮材料の伸張率が小さくなり、ゴム絶縁筒の拡径支持期間中における常温収縮材料の永久伸び量を小さくすることができ、同じ期間だけゴム絶縁筒を拡径状態で支持した場合には、ゴム絶縁筒の段剥ぎ端部の外周への装着時の界面面圧をより大きくすることができるので、常温収縮型接続部の電気性能を向上させることができる。また、同じ界面面圧を確保する場合には、拡径状態でのゴム絶縁筒の支持期間をより長くとることができるため、ゴムユニット、即ち、ゴム絶縁筒を保管、施工時の制約を緩和することができる。
【００１７】
更に、拡径支持筒に外側から加わる応力も低減されるため、ゴム絶縁筒を縮径するために、拡径支持筒を解体又は引き抜くことにより除去することが容易になり、ケーブル接続処理作業の施工性を向上させることができる。
【００１８】
また、遮蔽層を構成するシールドワイヤを折り返すために所定の長さに切断した場合には、シールドワイヤの折り返し部の切断面が段剥ぎ端部のケーブル絶縁体とケーブルシース間における段剥ぎ端部の上に位置し、ケーブル絶縁体の外表面に接触しないので、接続処理時にケーブル絶縁体を傷付ける危険性が小さい。これにより、接続部界面の電気性能を低下させる恐れがなくなり、接続部の信頼性を高めることができる。
【００１９】
また、請求項２記載のケーブル接続処理方法は、請求項１記載のケーブル接続処理方法において、前記段剥ぎ端部から露出された遮蔽層の基部の外周にテープ巻き処理による保護層を設け、遮蔽層の自由端側からシールドワイヤをケーブルシース側へ折り返すようにし、前記段剥ぎ端部のケーブル絶縁体又は／及び外部半導電層と前記シールドワイヤの切断面との接触を防止することを特徴とするケーブル接続処理方法。
【００２０】
このような構成によると、シールドワイヤを所定の長さに切断した場合に形成される切断面がケーブル絶縁体のほかに外部半導電層の外表面に接触するのを確実に防止することができ、接続部を組み立てる際、接続部界面の電気性能を低下させる危険性が更に小さくなり、高信頼性の接続部を得ることができるので好ましい。
【００２１】
更に、請求項３記載のケーブル接続処理方法は、請求項１又は２記載のケーブル接続処理方法において、前記段剥ぎ端部から露出された遮蔽層を構成するシールドワイヤの前記折り返し部の外周に抑えテープ巻き処理を施して抑えテープ巻層を設け、前記シールドワイヤのばらけを防止し、及び、前記拡径支持筒との接触を防止し、施工性を向上させ、かつ、前記抑えテープ巻層により前記ケーブル絶縁体の大気中への暴露を防止したことを特徴とするケーブル接続処理方法である。
【００２２】
このような構成によると、シールドワイヤの折り返し部の先端がばらけないので、ゴムユニットを導体接続前にケーブルシース側に通す際、若しくは、導体接続後にケーブルシース側から戻す際、シールドワイヤの折り返し部の先端がゴムユニットの拡径支持筒の内面に擦れたり引っかかったりするようなことが減少して、ゴムユニットを円滑に前後方向（ケーブル軸線方向）へ移動させることができ、施工性が向上する。また、ゴムユニットを移動させるときには、ケーブル絶縁体が大気中へ暴露状態になっているので、その暴露時間は接続部の品質管理上短い方がよいが、上記処理方法を使用することにより、より品質の優れた接続部を組み立てることできるので好ましい。
【００２３】
【発明の実施の形態】
次に本発明に係るケーブル接続処理方法の実施形態を図面により詳細に説明する。なお、従来技術で説明したものと同一の構成を有するものは、同一の符号を使用する。図１、２は電力ケーブル１、１の中間接続部を組み立てる場合のケーブル接続処理方法を示すものである。このケーブル接続処理方法を説明すると、先ず、２本の電力ケーブル１、１の接続すべき各端末を段剥ぎしてケーブルシース９の段剥ぎ切断端から遮水金属層８、遮蔽層７、導電性布テープ巻層６、外部半導電層５、ケーブル絶縁体４及び導体口出部３を順次段剥ぎすることにより段剥ぎ端部２を形成する。
【００２４】
次に、電力ケーブル１、１の両段剥ぎ端部２、２から露出された遮蔽層７を構成するシールドワイヤ７Ａをニッパ等で所定長さに切断する。そして、このシールドワイヤ７Ａをケーブル絶縁体４とケーブルシース間９で半径方向外側にケーブルシース９側へ向けて少なくとも１回折り返して折り返し部７Ｂを形成し、その折り返し部７Ｂを両者間の段剥ぎ端部２の上、例えば、外部半導電層５及び導電性布テープ巻層６の上に跨るように配置する。この際、シールドワイヤ７Ａの先端がケーブルシース９の上に乗らないようにすると共に、シールドワイヤ７Ａの折り返し部７Ｂが半径方向外側に膨らんで、ケーブルシース９の外径より太くならないようにする。また、シールドワイヤ７Ａの折り返し部７Ｂは後記するゴムユニット１０のゴム絶縁筒１３が被らないような位置に配置することが望ましい。
【００２５】
次に、紐状体１２を螺旋状に巻回して円筒状に形成された拡径支持筒１１の外周にゴム絶縁筒１３を拡径状態で支持してなるゴムユニット１０を、図２に示すように、右側の電力ケーブル１の段剥ぎ端部２からそのケーブルシース９側に予め通しておく。次に、両段剥ぎ端部２、２の導体口出部３を導体接続して導体接続部１４を形成する。
【００２６】
このようにして、電力ケーブル１、１の導体接続終了後、前記ゴムユニット１０を、前記ケーブルシース９側から図１に示すように両段剥ぎ端部２、２側、即ち、導体接続部１５の真上位置まで移動させる。次に、拡径支持筒１１を構成する紐状体１２を拡径支持筒１１の右端１１Ａ側から拡径支持筒１１の内側に通して図１の左側に引く抜き、ゴム絶縁筒１３を所定の位置に合わせながら拡径支持筒１１をその右端１１Ａから順次解体して除去する。これに伴って、ゴム絶縁筒１３をその右端１３Ａから順次縮径して行き、両段剥ぎ端部２、２の外周に、即ち、導体接続部１４、ケーブル絶縁体４、４の外周に、外部半導電層５、５に跨るようにして装着することにより常温収縮型接続部を組み立てる。なお、ゴムユニット１０の拡径支持筒１１として剛性金属筒を用いる場合には、ゴム絶縁筒１３を縮径するために、剛性金属筒を専用工具で引き抜いて除去する以外は前記接続処理方法と同様なので説明を省略する。
【００２７】
なお、図示しないが、前記段剥ぎ端部２から露出された遮蔽層７を構成するシールドワイヤ７Ａを折り返して折り返し部７Ｂを形成する作業は、遅くともゴムユニット１０を前記ケーブルシース９側から両段剥ぎ端部２、２側に移動させる前に完了していればよい。例えば、電力ケーブル１、１の段剥ぎ端部２、２を形成する以前に、予め一方の電力ケーブル１のケーブルシース９側にゴムユニット１０を通しておき、その後、段剥ぎ端部１を形成し、遮蔽層７を構成するシールドワイヤ７Ａの折り返し部７Ｂを形成するようにしてもよい。
【００２８】
上記したケーブル接続処理方法によると、シールドワイヤ７Ａの折り返し部７Ｂをケーブルシース９の上に配置しなくて済むので、ゴムユニット１０の拡径支持筒１１の内径をケーブルシース外径＋１ｍｍ程度の大きさに縮径でき、拡径支持筒１１の外周に拡径状態で支持するゴム絶縁筒１３の内径を従来のものより少なくとも４〜５ｍｍ小さくすることが可能である。これにより、ゴム絶縁筒１３を構成する常温収縮材料の伸張率が小さくなり、ゴム絶縁筒１３の拡径支持期間中における常温収縮材料の永久伸び量を小さくすることができ、同じ期間だけゴム絶縁筒１３を拡径状態で支持した場合には、ゴム絶縁筒１３の段剥ぎ端部２の外周への装着時の界面面圧をより大きくすることができるので、常温収縮型接続部の電気性能を向上させることができる。また、同じ界面面圧を確保する場合には、拡径状態でのゴム絶縁筒１３の支持期間をより長くとることができるため、ゴムユニット１０、即ち、ゴム絶縁筒１３を保管、施工時の制約を緩和することができる。
【００２９】
更に、拡径支持筒１１に外側から加わる応力も低減されるため、ゴム絶縁筒１３を縮径するために、拡径支持筒１１を解体又は引き抜くことにより除去することが容易になり、ケーブル接続処理作業の施工性を向上させることができる。
【００３０】
また、遮蔽層７を構成するシールドワイヤ７Ａを折り返すために所定の長さに切断した場合には、シールドワイヤ７Ａの折り返し部７Ｂの切断面７Ｃが段剥ぎ端部２のケーブル絶縁体４とケーブルシース９間における段剥ぎ端部２の上に位置し、ケーブル絶縁体４の外表面に接触しないので、接続処理時にケーブル絶縁体４を傷付ける危険性が小さい。これにより、接続部界面の電気性能を低下させる恐れがなくなり、接続部の信頼性を高めることができる。
【００３１】
前記遮蔽層７を構成するシールドワイヤ７Ａを、ケーブル絶縁体４とケーブルシース９間で折り返して折り返し部７Ｂを形成する方法は、図２に示す方法のほかに、例えば、図３に示すように、シールドワイヤ７Ａを段剥ぎ端部２の周方向に沿わせるように折り返して形成するようにしてもよい。このようにして折り返し部７Ｂを形成すると、折り返し部７Ｂが半径方向外側に膨らむのをより一層防止することができるので好ましい。
【００３２】
また、図４に示すものは、シールドワイヤ７Ａをケーブル絶縁体４とケーブルシース９間で半径方向外側にケーブルシース９側へ向けて折り返して折り返し部７Ｂを形成する前に、段剥ぎ端部２から露出された遮蔽層７の基部の外周にテープ巻き処理等による保護層１５を設け、遮蔽層７の自由端側からシールドワイヤ７Ａをケーブルシース９側へ折り返すようにしたものである。このように保護層１５を設けておくと、シールドワイヤ７Ａを所定の長さに切断した場合に形成される切断面７Ｃがケーブル絶縁体４のほかに外部半導電層５の外表面に接触するのを確実に防止することができ、接続部を組み立てる際、接続部界面の電気性能を低下させる危険性が更に小さくなり、高信頼性の接続部を得ることができるので好ましい。
【００３３】
更に、図５に示すものは、前記段剥ぎ端部２から露出された遮蔽層７を構成するシールドワイヤ７Ａの前記折り返し部７Ｂの外周に抑えテープ巻き処理を施して抑えテープ巻層１６を設けたものである。なお、図示省略するが、図４に示すように、遮蔽層７の基部に保護層１５を設けた後、シールドワイヤ７Ａをケーブルシース９側へ折り返して折り返し部７Ｂを形成した後、その折り返し部分７Ｂの外周に抑えテープ巻層１６を設けるようにしてもよい。このように抑えテープ巻層１６を設けると、シールドワイヤ７Ａの折り返し部７Ｂの先端がばらけないので、ゴムユニット１０を導体接続前にケーブルシース９側に通す際、若しくは、導体接続後にケーブルシース９側から戻す際、シールドワイヤ７Ａの折り返し部７Ｂの先端がゴムユニット１０の拡径支持筒１１の内面に擦れたり引っかかったりするようなことが減少して、ゴムユニット１０を円滑に前後方向（ケーブル軸線方向）へ移動させることができ、施工性が向上する。また、ゴムユニット１０を移動させるときには、ケーブル絶縁体４が大気中へ暴露状態になっているので、その暴露時間は接続部の品質管理上短い方がよいが、上記処理方法を使用することにより、より品質の優れた接続部を組み立てることできるので好ましい。
【００３４】
【発明の効果】
以上説明したように、本発明の請求項１記載のケーブル接続処理方法は、遅くともゴムユニットをケーブルシース側から両段剥ぎ端部側に移動させる前に、両段剥ぎ端部から露出された遮蔽層を構成するシールドワイヤを、ケーブル絶縁体とケーブルシース間で折り返して折り返し部を形成し、その折り返し部を両者間の段剥ぎ端部の上に配置しておくので、遮蔽層を構成するシールドワイヤの折り返し部をケーブルシースの上に配置しなくて済み、ゴムユニットの拡径支持筒の内径をケーブルシース外径＋１ｍｍ程度の大きさに縮径でき、拡径支持筒の外周に拡径状態で支持するゴム絶縁筒の内径を従来のものより少なくとも４〜５ｍｍ小さくすることが可能である。
【００３５】
これにより、ゴム絶縁筒を構成する常温収縮材料の伸張率が小さくなり、ゴム絶縁筒の拡径支持期間中における常温収縮材料の永久伸び量を小さくすることができ、同じ期間だけゴム絶縁筒を拡径状態で支持した場合には、ゴム絶縁筒の段剥ぎ端部の外周への装着時の界面面圧をより大きくすることができるので、常温収縮型接続部の電気性能を向上させることができる。また、同じ界面面圧を確保する場合には、拡径状態でのゴム絶縁筒の支持期間をより長くとることができるため、ゴムユニット、即ち、ゴム絶縁筒を保管、施工時の制約を緩和することができる。
【００３６】
更に、拡径支持筒に外側から加わる応力も低減されるため、ゴム絶縁筒を縮径するために、拡径支持筒を解体又は引き抜くことにより除去することが容易になり、ケーブル接続処理作業の施工性を向上させることができる。
【００３７】
また、遮蔽層を構成するシールドワイヤを折り返すために所定の長さに切断した場合には、シールドワイヤの折り返し部の切断面が段剥ぎ端部のケーブル絶縁体とケーブルシース間における段剥ぎ端部の上に位置し、ケーブル絶縁体の外表面に接触しないので、接続処理時にケーブル絶縁体を傷付ける危険性が小さい。これにより、接続部界面の電気性能を低下させる恐れがなくなり、接続部の信頼性を高めることができる。
【００３８】
また、請求項２記載のケーブル接続処理方法によると、請求項１記載のケーブル接続処理方法において、前記段剥ぎ端部から露出された遮蔽層の基部の外周にテープ巻き処理等による保護層を設け、遮蔽層の自由端側からシールドワイヤをケーブルシース側へ折り返すようにしたので、シールドワイヤを所定の長さに切断した場合に形成される切断面がケーブル絶縁体のほかに外部半導電層の外表面に接触するのを確実に防止することができ、接続部を組み立てる際、接続部界面の電気性能を低下させる危険性が更に小さくなり、高信頼性の接続部を得ることができるので好ましい。
【００３９】
更に、請求項３記載のケーブル接続処理方法によると、請求項１又は２記載のケーブル接続処理方法において、前記段剥ぎ端部から露出された遮蔽層を構成するシールドワイヤの前記折り返し部の外周に抑えテープ巻き処理を施して抑えテープ巻層を設けたので、シールドワイヤの折り返し部の先端がばらけるようなおとがなくなる。従って、ゴムユニットを導体接続前にケーブルシース側に通す際、若しくは、導体接続後にケーブルシース側から戻す際、シールドワイヤの折り返し部の先端がゴムユニットの拡径支持筒の内面に擦れたり引っかかったりするようなことが減少して、ゴムユニットを円滑に前後方向へ移動させることができ、施工性が向上する。また、ゴムユニットを移動させるときには、ケーブル絶縁体が大気中へ暴露状態になっているので、その暴露時間は接続部の品質管理上短い方がよいが、上記処理方法を使用することにより、より品質の優れた接続部を組み立てることできるので好ましい。
【図面の簡単な説明】
【図１】本発明に係るケーブル接続処理方法において、ゴムユニットをケーブルシース側から両段剥ぎ端部側に移動させ、ゴムユニットの拡径支持筒の解体を始める状態を断面で示す説明図である。
【図２】図１に示すケーブル接続処理方法において、ケーブルの段剥ぎ端部のシールドワイヤを、ケーブル絶縁体とケーブルシース間で半径外側にケーブルシース９側へ向けて折り返して折り返し部を形成し、その折り返し部を両者間の段剥ぎ端部の上に配置し、ゴムユニットを右側の段剥ぎ端部からケーブルシース側に通した状態を拡大断面で示す説明図である。
【図３】図２に示すシールドワイヤを、ケーブル絶縁体とケーブルシース間で周方向に沿わせるようにして折り返して折り返し部を形成し、その折り返し部を両者間の段剥ぎ端部の上に配置し、ゴムユニットを右側の段剥ぎ端部からケーブルシースの外周側に通した状態を拡大断面で示す説明図である。
【図４】図３において、段剥ぎ端部から露出された遮蔽層の基部の外周にテープ巻き処理等による保護層を設けた状態を拡大断面で示す説明図である。
【図５】図３において、前記段剥ぎ端部から露出された遮蔽層を構成するシールドワイヤの前記折り返し部の外周に抑えテープ巻き処理を施して抑えテープ巻層を設けた状態を拡大断面で示す説明図である。
【図６】従来のケーブル接続処理方法において、ゴムユニットを段剥ぎ端部の外周に移動させ、ゴムユニットの拡径支持筒の解体を始める状態を断面で示す説明図である。
【図７】従来のケーブル接続処理方法において、ケーブルの段剥ぎ端部のシールドワイヤをケーブルシース側へ折り返してケーブルシースの上に配置し、ゴムユニットを右側の段剥ぎ端部からケーブルシースの外周に通した状態を断面で示す説明図である。
【図８】従来のケーブル接続処理方法において、ケーブルの段剥ぎ端部のシールドワイヤを折り返さずに段剥ぎ端部のケーブル絶縁体の外表面に沿わせておき、ゴムユニットを右側の段剥ぎ端部からケーブルシースの外周に通した状態を断面で示す説明図である。
【符号の説明】
１電力ケーブル
２段剥ぎ端部
３導体口出部
４ケーブル絶縁体
５外部半導電層
６導電性布テープ巻層
７遮蔽層
７Ａシールドワイヤ
７Ｂ折り返し部
７Ｃ切断面
８遮水金属層
９ケーブルシース
１０ゴムユニット
１１拡径支持筒
１１Ａ右端
１２紐状体
１３ゴム絶縁筒
１３Ａ右端
１４導体接続部
１５保護層
１６抑えテープ巻層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cable connection processing method when assembling a connection portion of a cold-shrink type power cable.
[0002]
[Prior art]
In recent years, in order to improve the workability of the intermediate connection part of the power cable, a rubber unit in which a cold-shrinkable rubber insulating cylinder is supported in an expanded state on the outer periphery of the expanded diameter supporting cylinder has been used. It is coming. This rubber insulating cylinder is made of a normal temperature shrinkable material such as silicone rubber or EP rubber, and is formed by integrally molding an internal semiconductive layer, an external semiconductive layer, a stress cone layer, and a reinforcing insulating layer. This type of room temperature shrinkable connection using a rubber insulated cylinder is designed to maintain interface electrical performance by generating interface pressure due to the elastic force of the room temperature shrinkable material. It is formed thinner than the outer diameter.
[0003]
This room temperature shrinkable connection part has features such that the number of parts is small and the connection process is simple, and quality control at the time of assembly is easy. In general, the cold-shrinkable connection part is a one-piece type made of rubber, so the point of quality control at the time of assembly is the interface state between the cable insulator and the rubber insulating cylinder, that is, protrusions, scratches, foreign matter, and the close contact state between the two. . If the interface state is poor, the electrical performance of the connecting portion may be significantly reduced.
[0004]
The one-piece type rubber insulating cylinder is expanded in advance at the factory or assembly site so that the inner diameter thereof is larger than the outer diameter of the cable sheath of the power cable, and is supported on the outer periphery of the cylindrical expanded support cylinder in an expanded state. The former diameter expansion method is called the factory diameter expansion method, and the latter diameter expansion method is called the field diameter expansion method. The diameter-expanded support cylinder is generally formed of a cylindrical string formed by spirally winding a plastic string such as polypropylene, or a circular rigid metal cylinder (rigid metal pipe).
[0005]
A cable connection processing method using a rubber unit in which a rubber insulating cylinder is supported in an expanded state on the outer periphery of an expanded diameter supporting cylinder formed by spirally winding the cord-like body will be described with reference to FIGS. To do. First, the terminals to be connected to the power cables 1 and 1 are stepped off, and the water shielding metal layer 8, the shielding layer 7, the conductive cloth tape winding layer 6, and the external semiconductive layer 5 from the stepped cut end of the cable sheath 9. Then, the stepped end portion 2 is formed by stepping the cable insulator 4 and the conductor lead-out portion 3 sequentially. Next, the shield wire 7 </ b> A constituting the shielding layer 7 is folded back toward the cable sheath 9, and the folded portion 7 </ b> B is disposed on the cable sheath 9. Next, before the conductor connection, the rubber unit 10 formed by supporting the rubber insulating cylinder 13 in an expanded state on the outer periphery of the diameter-enlarged support cylinder 11 formed by spirally winding the string-like body 12 is formed. Then, as shown in FIG. 7, one step stripped end portion 3 of the power cables 1, 1 is passed in advance from the right step stripped end portion 2 to the cable sheath 9 side. Next, the conductor connection portions 14 are formed by conductor-connecting the conductor lead-out portions 3 of the two-stage stripped end portions 2 and 2.
[0006]
Thus, after connecting the conductors of the power cables 1 and 1, the rubber unit 10 is connected to both the stripped end portions 2 and 2, that is, the conductor connecting portions 14 from the cable sheath 9 side as shown in FIG. 6. Move up. Next, the string-like body 12 constituting the diameter expansion support cylinder 11 is pulled out from the right end 11A side of the diameter expansion support cylinder 11 through the inside of the diameter expansion support cylinder 11 and pulled to the left side in FIG. The diameter-enlarged support cylinder 11 is sequentially disassembled from the right end 11A and removed while adjusting to the position. Accordingly, the diameter of the rubber insulating cylinder 13 is sequentially reduced from the right end 13A, and the outer periphery of the stepped end portions 2 and 2, that is, the outer periphery of the conductor connecting portion 14 and the cable insulators 4 and 4, A room temperature shrinkable connecting portion is assembled by mounting so as to straddle the semiconductive layers 5 and 5. When a rigid metal cylinder is used as the diameter-enlarging support cylinder 11 of the rubber unit 10, in order to reduce the diameter of the rubber insulating cylinder 13, the connection processing method is used except that the rigid metal cylinder is pulled out and removed with a dedicated tool. It is the same.
[0007]
[Problems to be solved by the invention]
In the cable connection processing method when assembling the room temperature shrinkable connection portion, the rubber unit 10 provided with the rubber insulating cylinder 13 in advance is placed on one cable sheath 9 side in either case of the factory diameter expansion method or the field diameter expansion method. Therefore, it is necessary to expand the inner diameter of the rubber insulating cylinder 13 by a size that is equal to the outer diameter of the cable sheath 9 plus at least the amount corresponding to twice the wall thickness of the expanded diameter supporting cylinder 11. is there.
[0008]
Further, when connecting the shield layer 7 of the power cable 1 composed of the shield wire 7A, it is necessary to arrange the folded portion 7B of the shield wire 7A on the cable sheath 9 as shown in FIG. Therefore, it is necessary to enlarge the shield wire 7A by an amount corresponding to the outer diameter x 2 times. Specifically, since the shield wire 7A generally has an outer diameter of 1.2 mmφ, when the folded portion 7B of the shield wire 7A is disposed on the cable sheath 9, the inner diameter of the rubber insulating cylinder 13 is at least It is necessary to expand larger by 2.4 mmφ. Actually, since the root of the folded portion 7B swells as shown in FIG. 7, it is necessary to enlarge it by 4 to 5 mm.
[0009]
When a long time elapses in a state where the rubber insulating cylinder 13 is extended by expanding the diameter, the permanent elongation amount of the normal temperature shrinkable material increases and the elastic force decreases. Then, since the interfacial surface pressure when the rubber insulating cylinder 13 is attached to the outer periphery of the stepped end portion 2 is lowered, there is a possibility that the interfacial electrical performance of the normal temperature shrinkable connection portion is lowered.
[0010]
When designing the rubber insulating cylinder 13, the inner diameter of the rubber insulating cylinder 13 is made smaller in consideration of the amount of permanent elongation at the time of such expansion, and the interface pressure when the rubber insulating cylinder 13 is attached is increased. It is also possible. However, in this case, since the external pressure applied to the enlarged diameter support cylinder 11 increases, the rubber insulating cylinder 13 is supported on the outer periphery of the enlarged diameter support cylinder 11 in an expanded state, or the expanded diameter support cylinder 11 is disassembled or disassembled. It may be difficult to remove by pulling, and the workability may be deteriorated, and the expanded diameter support cylinder 11 may collapse during storage or assembly of the rubber unit 10.
[0011]
On the other hand, as shown in FIG. 8, it is also conceivable to keep the shield wire 7A constituting the shielding layer 7 along the outer surface of the cable insulator 4 at the stepped end 2 without being folded back as described above. In this case, the inner diameter of the expanded diameter support cylinder 11 of the rubber unit 10, that is, the inner diameter of the rubber insulating cylinder 13 can be reduced, but when the shield wire 7A is cut to a predetermined length with a nipper or the like, Since the cut surface 7C at the tip is very sharp, this is in contact with the outer surface of the cable insulator 4 and easily damages the outer surface of the insulator 4, which causes the interface electrical performance of the normal temperature contraction type connection portion to deteriorate. .
[0012]
As a countermeasure, a protective tape may be wound around the outer periphery of the cable insulator 4 to protect the outer surface of the cable insulator, which is the most important quality control point for construction. It is not preferable because a foreign matter such as a small piece of tape or an adhesive easily adheres.
[0013]
The amount of permanent elongation of the rubber insulating cylinder 13 depends on the elongation rate (elongation magnitude) of the normal temperature shrinkable material and the period during which the elongation is acting. For this reason, it is desirable to reduce the expansion rate of the rubber insulating cylinder 13 as much as possible and to shorten the diameter expansion support time of the rubber insulating cylinder 13 as much as possible. However, in order to shorten the latter diameter expansion support time, when the rubber insulating cylinder 13 is supported on the outer periphery of the diameter expansion support cylinder 11 by the factory expansion method, it is used for cable connection processing from factory shipment of the rubber unit 10. There is a restriction that must be shortened. Further, when the rubber insulating cylinder 13 is supported on the outer periphery of the diameter expansion support cylinder 11 by the field expansion method, the diameter expansion support of the rubber insulation cylinder 13 is performed in a site where the working environment and facilities are not sufficiently maintained than the former. There is a restriction that the support to the cylinder 11 and the mounting to the stepped-off end 2 must be completed in a short time, which causes a considerable hindrance to the construction work. For this reason, it is not easy to shorten the diameter expansion support time of the rubber insulating cylinder 13.
[0014]
The present invention has been made to solve the above-described problems. When the rubber insulating cylinder is supported in an expanded state on the diameter expansion supporting cylinder of the rubber unit, the expansion ratio of the normal temperature shrinkable material constituting the rubber insulating cylinder is reduced. Reduce the permanent elongation of the normal temperature shrinkable material during the expansion support period of the rubber insulating cylinder, and increase the interfacial pressure at the time of mounting to the stepped end of the rubber insulating cylinder, In addition to improving the interfacial electrical performance, a cable connection processing method is provided that does not impair the ease of construction and quality control of conventional connection assembly.
[0015]
[Means for Solving the Problems]
In the cable connection processing method according to claim 1 of the present invention for solving the above-mentioned problems, the shielding layer is a shield wire of a rubber unit formed by supporting a cold-shrinkable rubber insulating cylinder in an expanded state on the outer periphery of the expanded diameter supporting cylinder. Passing in advance through one cable sheath side of the power cable composed of the following, after the conductor is connected, the rubber unit is moved from the cable sheath side to the both ends of the power cable, and the diameter expansion support cylinder of the rubber unit In the cable connection processing method in which the rubber insulating cylinder is reduced in diameter by removing the cable and attached to the outer periphery of both stripped ends, the rubber unit is moved from the cable sheath side to the both stripped ends at the latest. Before, the shield wire that constitutes the shielding layer exposed from both stripped ends is folded between the cable insulator and the cable sheath to form a folded portion, and the folded That it placed on the stage stripping edge therebetween a Thus, the inner diameter of the expanded diameter support cylinder can be suppressed by an increase of about 1 mm with respect to the outer diameter of the cable sheath, the permanent elongation amount of the normal temperature shrinkable material of the normal temperature shrinkable rubber insulating cylinder can be reduced, and the normal temperature shrinkable rubber Increased interfacial pressure when installing the insulation cylinder Characterized by Cable connection processing Is the method.
[0016]
With the above configuration, since the folded portion of the shield wire constituting the shielding layer does not need to be disposed on the cable sheath, the inner diameter of the expanded support cylinder of the rubber unit can be reduced to the size of the outer diameter of the cable sheath plus about 1 mm. The inner diameter of the rubber insulating cylinder supported in the expanded state on the outer periphery of the expanded diameter supporting cylinder can be made at least 4 to 5 mm smaller than the conventional one. As a result, the stretch rate of the normal temperature shrinkable material constituting the rubber insulated cylinder is reduced, and the permanent elongation amount of the normal temperature shrinkable material during the diameter expansion support period of the rubber insulated cylinder can be reduced. When supported in an expanded state, the interface pressure at the time of mounting to the outer periphery of the stepped end of the rubber insulating cylinder can be increased, which can improve the electrical performance of the cold-shrinkable connection part. it can. In addition, if the same interfacial pressure is ensured, the rubber insulation cylinder can be supported for a longer time in the expanded diameter state, so the rubber unit, that is, the rubber insulation cylinder, can be stored to ease restrictions during construction. can do.
[0017]
Furthermore, since the stress applied from the outside to the expanded diameter support cylinder is also reduced, in order to reduce the diameter of the rubber insulating cylinder, it becomes easy to remove the expanded diameter support cylinder by disassembling or pulling out the cable connection processing work. Workability can be improved.
[0018]
Further, when the shield wire constituting the shielding layer is cut to a predetermined length in order to fold back, the cut surface of the folded portion of the shield wire is the stepped end portion between the cable insulator at the stepped end portion and the cable sheath. Since it is located above and does not contact the outer surface of the cable insulation, there is little risk of damaging the cable insulation during the connection process. Thereby, there is no fear that the electrical performance at the interface of the connection portion is reduced, and the reliability of the connection portion can be improved.
[0019]
According to a second aspect of the present invention, there is provided the cable connection processing method according to the first aspect, wherein a protective layer is provided by a tape winding process on the outer periphery of the base portion of the shielding layer exposed from the stepped end portion. The shield wire should be folded back to the cable sheath from the free end side of the layer. Preventing contact between the cable insulation at the stripped end and / or the external semiconductive layer and the cut surface of the shield wire It is characterized by Cable connection processing Method.
[0020]
According to such a configuration, it is possible to reliably prevent the cut surface formed when the shield wire is cut to a predetermined length from contacting the outer surface of the external semiconductive layer in addition to the cable insulator. When assembling the connection portion, the risk of lowering the electrical performance of the connection portion interface is further reduced, and a highly reliable connection portion can be obtained, which is preferable.
[0021]
Furthermore, the cable connection processing method according to claim 3 is the cable connection processing method according to claim 1 or 2, wherein the cable connection processing method is suppressed to the outer periphery of the folded portion of the shield wire constituting the shielding layer exposed from the stepped end portion. A tape winding layer is provided with a tape winding process. The shield wire is prevented from being scattered, and the contact with the diameter-enlarged support tube is prevented, the workability is improved, and the cable insulation is exposed to the atmosphere by the holding tape winding layer. Prevented It is characterized by Cable connection processing Is the method.
[0022]
According to such a configuration, since the tip of the folded portion of the shield wire does not come apart, when passing the rubber unit through the cable sheath before connecting the conductor, or when returning the cable unit from the cable sheath after connecting the conductor, the shield wire is folded back. The tip of the part is less likely to rub or get caught on the inner surface of the expansion support cylinder of the rubber unit, and the rubber unit can be smoothly moved in the front-rear direction (cable axis direction), improving workability To do. Also, when moving the rubber unit, the cable insulation is exposed to the atmosphere, so the exposure time is better for quality control of the connection part, but by using the above processing method, This is preferable because a connecting portion with excellent quality can be assembled.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a cable connection processing method according to the present invention will be described in detail with reference to the drawings. In addition, what has the same structure as what was demonstrated by the prior art uses the same code | symbol. 1 and 2 show a cable connection processing method when assembling an intermediate connection portion of the power cables 1 and 1. The cable connection processing method will be described. First, each terminal to be connected to the two power cables 1 and 1 is stepped, and the water shielding metal layer 8, the shielding layer 7, and the conductive layer are cut from the stepped cut end of the cable sheath 9. The stepped end portion 2 is formed by stepping the conductive cloth tape winding layer 6, the outer semiconductive layer 5, the cable insulator 4 and the conductor lead-out portion 3 in order.
[0024]
Next, the shield wire 7A constituting the shielding layer 7 exposed from the two-stage peeled ends 2 and 2 of the power cables 1 and 1 is cut into a predetermined length with a nipper or the like. Then, the shield wire 7A is turned back at least once toward the cable sheath 9 radially outwardly between the cable insulator 4 and the cable sheath 9 to form a folded portion 7B, and the folded portion 7B is stripped between the two. It arrange | positions so that it may straddle on the edge part 2, for example, the outer semiconductive layer 5 and the conductive cloth tape winding layer 6. FIG. At this time, the tip of the shield wire 7A is prevented from getting on the cable sheath 9, and the folded portion 7B of the shield wire 7A is swelled outward in the radial direction so as not to be thicker than the outer diameter of the cable sheath 9. Further, it is desirable to arrange the folded portion 7B of the shield wire 7A at a position where the rubber insulating cylinder 13 of the rubber unit 10 which will be described later is not covered.
[0025]
Next, FIG. 2 shows a rubber unit 10 in which a rubber insulating cylinder 13 is supported in an expanded state on the outer periphery of a diameter-enlarged support cylinder 11 formed by winding a string-like body 12 in a spiral shape. As described above, the right power cable 1 is passed in advance from the stepped end portion 2 to the cable sheath 9 side. Next, the conductor connection portion 14 is formed by conductor-connecting the conductor lead-out portions 3 of the two stripped end portions 2 and 2.
[0026]
Thus, after the conductor connection of the power cables 1 and 1 is completed, the rubber unit 10 is separated from the cable sheath 9 side as shown in FIG. Move to the position just above. Next, the string-like body 12 constituting the diameter-enlarged support cylinder 11 is pulled out from the right end 11A side of the diameter-enlarged support cylinder 11 to the inside of the diameter-enlarged support cylinder 11 and pulled to the left side in FIG. The diameter-enlarged support cylinder 11 is sequentially disassembled from the right end 11A and removed while adjusting to the position. Along with this, the diameter of the rubber insulating cylinder 13 is sequentially reduced from the right end 13A, and on the outer periphery of both stripped end portions 2 and 2, that is, on the outer periphery of the conductor connecting portion 14 and the cable insulators 4 and 4, A room temperature shrinkable connection portion is assembled by mounting so as to straddle the outer semiconductive layers 5 and 5. When a rigid metal cylinder is used as the diameter-enlarging support cylinder 11 of the rubber unit 10, in order to reduce the diameter of the rubber insulating cylinder 13, the connection processing method is used except that the rigid metal cylinder is pulled out and removed with a dedicated tool. Since it is the same, description is abbreviate | omitted.
[0027]
Although not shown, the work of forming the folded portion 7B by folding back the shield wire 7A constituting the shielding layer 7 exposed from the stepped strip end 2 is performed at the latest from the side of the cable sheath 9 on both sides of the rubber unit 10. What is necessary is just to complete before moving to the peeling edge part 2 and 2 side. For example, before forming the stepped end portions 2 and 2 of the power cables 1 and 1, the rubber unit 10 is passed through the cable sheath 9 side of one power cable 1 in advance, and then the stepped end portion 1 is formed. You may make it form the folding | turning part 7B of the shield wire 7A which comprises the shielding layer 7. FIG.
[0028]
According to the cable connection processing method described above, the folded portion 7B of the shield wire 7A does not have to be disposed on the cable sheath 9, so that the inner diameter of the expanded support cylinder 11 of the rubber unit 10 is as large as the outer diameter of the cable sheath plus about 1 mm. The inner diameter of the rubber insulating cylinder 13 supported in the expanded state on the outer periphery of the expanded diameter support cylinder 11 can be made at least 4 to 5 mm smaller than the conventional one. As a result, the expansion rate of the normal temperature shrinkable material constituting the rubber insulating cylinder 13 is reduced, and the permanent elongation amount of the normal temperature shrinkable material during the diameter expansion support period of the rubber insulating cylinder 13 can be reduced. When the cylinder 13 is supported in an expanded state, the interface surface pressure when the rubber insulating cylinder 13 is attached to the outer periphery of the stepped end portion 2 can be increased. Can be improved. Further, when the same interfacial pressure is secured, the support period of the rubber insulating cylinder 13 in the expanded diameter state can be made longer, so that the rubber unit 10, that is, the rubber insulating cylinder 13 is stored and installed. Restrictions can be relaxed.
[0029]
Further, since the stress applied from the outside to the diameter-enlarged support cylinder 11 is also reduced, it is easy to remove the diameter-enlarged support cylinder 11 by disassembling or pulling it out in order to reduce the diameter of the rubber insulating cylinder 13. The workability of the processing work can be improved.
[0030]
When the shield wire 7A constituting the shielding layer 7 is cut to a predetermined length in order to be folded back, the cut surface 7C of the folded portion 7B of the shield wire 7A is connected to the cable insulator 4 and the cable at the stepped end portion 2. Since it is located on the stepped end portion 2 between the sheaths 9 and does not contact the outer surface of the cable insulator 4, the risk of damaging the cable insulator 4 during connection processing is small. Thereby, there is no fear that the electrical performance at the interface of the connection portion is reduced, and the reliability of the connection portion can be improved.
[0031]
The method of forming the folded portion 7B by folding the shield wire 7A constituting the shielding layer 7 between the cable insulator 4 and the cable sheath 9 is, for example, as shown in FIG. The shield wire 7A may be formed by being folded back along the circumferential direction of the stepped end portion 2. Forming the folded portion 7B in this manner is preferable because the folded portion 7B can be further prevented from expanding outward in the radial direction.
[0032]
4 shows that the shield wire 7A is folded between the cable insulator 4 and the cable sheath 9 outward in the radial direction toward the cable sheath 9 to form the folded portion 7B before forming the stepped end 2B. A protective layer 15 by tape winding or the like is provided on the outer periphery of the base portion of the shielding layer 7 exposed from the shield layer 7 so that the shield wire 7A is folded back from the free end side of the shielding layer 7 to the cable sheath 9 side. When the protective layer 15 is thus provided, the cut surface 7C formed when the shield wire 7A is cut to a predetermined length comes into contact with the outer surface of the external semiconductive layer 5 in addition to the cable insulator 4. Therefore, when assembling the connecting portion, the risk of lowering the electrical performance of the connecting portion interface is further reduced, and a highly reliable connecting portion can be obtained.
[0033]
Further, the one shown in FIG. 5 is provided with a tape winding layer 16 by performing a tape winding process on the outer periphery of the folded portion 7B of the shield wire 7A constituting the shielding layer 7 exposed from the stepped end 2. It is a thing. Although not shown in the figure, as shown in FIG. 4, after the protective layer 15 is provided at the base of the shielding layer 7, the shield wire 7A is folded back toward the cable sheath 9 to form the folded portion 7B, and then the folded portion. You may make it provide the tape winding layer 16 restraining on the outer periphery of 7B. When the tape winding layer 16 is provided in this manner, the tip of the folded portion 7B of the shield wire 7A does not come apart. Therefore, when the rubber unit 10 is passed through the cable sheath 9 before the conductor is connected, or after the conductor is connected, the cable sheath When returning from the 9 side, the tip of the folded portion 7B of the shield wire 7A is less likely to be rubbed or caught on the inner surface of the diameter-enlarged support tube 11 of the rubber unit 10, and the rubber unit 10 is smoothly moved in the front-rear direction ( It can be moved in the direction of the cable axis), improving workability. Further, when the rubber unit 10 is moved, since the cable insulator 4 is exposed to the atmosphere, the exposure time is better in terms of quality control of the connection part, but by using the above processing method, It is preferable because a connection portion with higher quality can be assembled.
[0034]
【The invention's effect】
As described above, in the cable connection processing method according to claim 1 of the present invention, the shield exposed from both stripped ends before moving the rubber unit from the cable sheath side to both stripped ends at the latest. The shield wire constituting the shielding layer is formed by folding the shield wire constituting the layer between the cable insulator and the cable sheath to form the folded portion and placing the folded portion on the stepped end portion between the two. There is no need to place the folded part of the wire on the cable sheath, the inner diameter of the expanded support cylinder of the rubber unit can be reduced to the size of the outer diameter of the cable sheath plus about 1 mm, and the expanded diameter around the outer diameter of the expanded diameter support cylinder It is possible to make the inner diameter of the rubber insulating cylinder supported by the at least 4 to 5 mm smaller than the conventional one.
[0035]
As a result, the stretch rate of the normal temperature shrinkable material constituting the rubber insulated cylinder is reduced, and the permanent elongation amount of the normal temperature shrinkable material during the diameter expansion support period of the rubber insulated cylinder can be reduced. When supported in an expanded state, the interface pressure at the time of mounting to the outer periphery of the stepped end of the rubber insulating cylinder can be increased, which can improve the electrical performance of the cold-shrinkable connection part. it can. In addition, if the same interfacial pressure is ensured, the rubber insulation cylinder can be supported for a longer time in the expanded diameter state, so the rubber unit, that is, the rubber insulation cylinder, can be stored to ease restrictions during construction. can do.
[0036]
Furthermore, since the stress applied from the outside to the expanded diameter support cylinder is also reduced, in order to reduce the diameter of the rubber insulating cylinder, it becomes easy to remove the expanded diameter support cylinder by disassembling or pulling it out. Workability can be improved.
[0037]
In addition, when the shield wire constituting the shielding layer is cut to a predetermined length so that the shield wire is folded, the cut surface of the folded portion of the shield wire is the stepped end portion between the cable insulator at the stepped end portion and the cable sheath. Since it is located above and does not contact the outer surface of the cable insulation, the risk of damaging the cable insulation during the connection process is small. Thereby, there is no fear that the electrical performance at the interface of the connection portion is lowered, and the reliability of the connection portion can be improved.
[0038]
Moreover, according to the cable connection processing method of claim 2, in the cable connection processing method of claim 1, a protective layer is provided by tape winding or the like on the outer periphery of the base portion of the shielding layer exposed from the stepped end portion. Since the shield wire is folded back to the cable sheath side from the free end side of the shield layer, the cut surface formed when the shield wire is cut to a predetermined length is not only the cable insulator but also the external semiconductive layer. It is possible to reliably prevent contact with the outer surface, and when assembling the connection portion, the risk of lowering the electrical performance at the interface of the connection portion is further reduced, and a highly reliable connection portion can be obtained, which is preferable. .
[0039]
Furthermore, according to the cable connection processing method according to claim 3, in the cable connection processing method according to claim 1 or 2, on the outer periphery of the folded portion of the shield wire constituting the shielding layer exposed from the stepped end portion. Since the suppression tape winding process is performed and the suppression tape winding layer is provided, there is no possibility that the tip of the folded portion of the shield wire is scattered. Therefore, when passing the rubber unit through the cable sheath before connecting the conductor, or when returning from the cable sheath side after connecting the conductor, the tip of the folded portion of the shield wire rubs or gets caught on the inner surface of the expanded diameter support cylinder of the rubber unit. As a result, the rubber unit can be smoothly moved in the front-rear direction, and workability is improved. Also, when moving the rubber unit, the cable insulation is exposed to the atmosphere, so the exposure time should be shorter in terms of quality control of the connection part. This is preferable because a connecting portion with excellent quality can be assembled.
[Brief description of the drawings]
In the cable connection processing method according to the present invention, the rubber unit is moved from the cable sheath side to the two-stage peeled end side, and the state of starting the dismantling of the diameter-enlarged support cylinder of the rubber unit is shown in cross section is there.
2 is a cable connection processing method shown in FIG. 1, in which the shield wire at the stepped end portion of the cable is folded back radially outward toward the cable sheath 9 between the cable insulator and the cable sheath to form a folded portion. FIG. 5 is an explanatory view showing, in an enlarged cross-section, a state in which the folded portion is disposed on the stepped end portion between them and the rubber unit is passed from the right stepped end portion to the cable sheath side.
FIG. 3 shows the shield wire shown in FIG. 2 folded back along the circumferential direction between the cable insulator and the cable sheath to form a folded portion, and the folded portion is placed on the stepped end portion between the two. It is explanatory drawing which shows the state which has arrange | positioned and let the rubber unit pass to the outer peripheral side of the cable sheath from the stepped edge part of the right side.
FIG. 4 is an explanatory view showing, in an enlarged cross-section, a state in which a protective layer is provided by tape winding or the like on the outer periphery of the base portion of the shielding layer exposed from the stepped end portion in FIG. 3;
FIG. 5 is an enlarged cross-sectional view showing a state in which a tape winding layer is provided by performing a tape winding process on the outer periphery of the folded portion of the shield wire constituting the shielding layer exposed from the stepped end portion in FIG. 3; It is explanatory drawing shown.
FIG. 6 is an explanatory view showing in cross section a state in which the rubber unit is moved to the outer periphery of the stepped end portion and dismantling of the diameter-enlarged support cylinder of the rubber unit is started in the conventional cable connection processing method.
FIG. 7 shows a conventional cable connection processing method in which a shield wire at a stepped end of a cable is folded back toward the cable sheath and placed on the cable sheath, and a rubber unit is placed on the outer periphery of the cable sheath from the stepped end on the right side. It is explanatory drawing which shows the state passed through in the cross section.
FIG. 8 shows a conventional cable connection processing method in which the shield wire at the stepped end portion of the cable is not folded back but along the outer surface of the cable insulation at the stepped end portion, and the rubber unit is placed on the right stepped end portion. It is explanatory drawing which shows the state which passed along the outer periphery of the cable sheath from the part in a cross section.
[Explanation of symbols]
1 Power cable
Two-step stripped edge
3 Conductor outlet
4 Cable insulation
5 External semiconductive layer
6 Conductive cloth tape winding layer
7 Shielding layer
7A Shielded wire
7B Folding part
7C cut surface
8 Impermeable metal layer
9 Cable sheath
10 Rubber unit
11 Expanded support cylinder
11A right end
12 String
13 Rubber insulation cylinder
13A right end
14 Conductor connection
15 Protective layer
16 Reducing tape winding layer

Claims

A rubber unit formed by supporting a normal temperature shrinkable rubber insulating cylinder in an expanded state on the outer periphery of the diameter expansion support cylinder is passed in advance through one cable sheath side of the power cable in which the shielding layer is formed of a shield wire. After connection, the rubber unit is moved from the cable sheath side to the two stripped ends of the power cable, and the diameter of the rubber insulating tube is reduced by removing the diameter-enlarging support tube of the rubber unit, so that the two stripped ends are removed. In the cable connection processing method adapted to be attached to the outer periphery, before moving the rubber unit from the cable sheath side to the two-stage peeled end side at the latest, the shield wire constituting the shielding layer exposed from the two-stage peeled end parts and by a folded portion formed by folding between the cable insulation and the cable sheath, keep placing the folded portion to the top of the stages strip end therebetween, said radially enlarged support The inner surface of the cable sheath is suppressed by an increase of about 1 mm with respect to the outer diameter of the cable sheath, the permanent elongation amount of the room temperature shrinkable material of the room temperature shrinkable rubber insulation cylinder is reduced, and the interface surface when the room temperature shrinkage type rubber insulation cylinder is mounted A cable connection processing method characterized by increasing the pressure .

2. The cable connection processing method according to claim 1, wherein a protective layer is provided by tape winding on the outer periphery of the base portion of the shielding layer exposed from the stepped end portion, and the shield wire is moved from the free end side of the shielding layer to the cable sheath side. A cable connection processing method characterized in that it is folded back to prevent contact between the cable insulator or / and the external semiconductive layer at the stepped end and the cut surface of the shield wire .

In the cable connection processing method according to claim 1 or 2, a tape winding layer is provided by performing a tape winding process on the outer periphery of the folded portion of the shield wire constituting the shielding layer exposed from the stepped end , Prevents the shield wire from falling apart, prevents contact with the expanded diameter support cylinder, improves workability, and prevents the cable insulator from being exposed to the atmosphere by the holding tape winding layer. A cable connection processing method characterized by that.