1378475 (1) 九、發明說明 【發明所屬之技術領域】 本發明係關於避雷器，特別是關於具備以氧化鋅爲主 成分之複數個非直線阻抗元件（以下，稱爲「避雷器元件 j )之層積體（以下，稱爲「避雷器元件層積體」）之避 雷器。 -φ 【先前技術】 一般，於設置於發電廠與變電所等之氣體絕緣開關裝 置，爲了保護開關裝置與變壓器等之電器免於打雷時從線 路侵入之異常電壓的損害，因而，配設有避雷器。 以往，此種避雷器知道有：如第16圖所示般，係將 避雷器元件層積體100立設於裝入有絕緣氣體之桶100的 底部110a，介由絕緣支撐筒120來加以支撐者（例如， 非專利文獻1)，或如第17圖所示般，於機器殼體210 Φ 的內壁氣密地安裝襯套220，將避雷器元件層積體230可 裝卸自如地裝置於此襯套220而形成（例如，專利文獻1 )。另外，第16圖中，符號〗40係表示高壓側之偏心屛 蔽體50係表示絕緣間隔物，丨6〇係表示儀器箱，1 7〇 係表示吸附劑》 但是’在前者之避雷器中，爲了使構成避雷器元件層 積體100之避雷器元件的電壓分攤均勻化，必須於避雷器 元件層積體]00的高壓側設置大型的屏蔽體130，因此， 有機器本身變大型化的缺點，另外，於進行具有避雷器元 -6- 13784751378475 (1) EMBODIMENT OF THE INVENTION [Technical Field] The present invention relates to a lightning arrester, and more particularly to a layer including a plurality of non-linear impedance elements (hereinafter referred to as "arrestor element j") mainly composed of zinc oxide. The arrester of the integrated body (hereinafter referred to as the "arrestor element laminate"). - φ [Prior technology] In general, gas-insulated switchgears installed in power plants and substations are designed to protect electrical appliances such as switchgear and transformers from damage caused by abnormal voltages from the line during thunder. There are lightning arresters. Conventionally, such a lightning arrester knows that, as shown in Fig. 16, the arrester element laminate 100 is erected on the bottom portion 110a of the tub 100 in which the insulating gas is filled, and is supported by the insulating support cylinder 120 ( For example, in Non-Patent Document 1), or as shown in Fig. 17, the bushing 220 is airtightly attached to the inner wall of the machine casing 210 Φ, and the arrester element laminated body 230 is detachably attached to the bushing. It is formed by 220 (for example, Patent Document 1). In addition, in Fig. 16, the symbol 40 indicates that the eccentric shielding body 50 on the high pressure side indicates an insulating spacer, the 丨6 〇 indicates an instrument case, and the 1 7 〇 indicates an adsorbent "but in the former arrester, In order to uniformize the voltage distribution of the arrester elements constituting the arrester element laminate 100, it is necessary to provide a large shield 130 on the high voltage side of the arrester element laminate 00, and therefore, the size of the organic body itself is increased. For carrying the arrester element-6-1378475
件層積體〗00之絕緣開關裝置（以下，稱爲「GIS ( Gas Insulated Switchgear)」）之耐電壓試驗時，必須將避雷 . 器元件層積體1〇〇從主電路導體（未圖示出）予以切離， . 所以，需要設置切離裝置（未圖示出），因此，存在有機 器構造變得複雜之缺點。 另一方面，在後者之避雷器中，雖不需要設置切離裝 置的關係，構造可以簡化，另外，於進行耐電壓試驗時， 能使將機器殻體210內的絕緣氣體加以回收、加以塡充之 作業成爲不需要，但是，存在有如下之缺點。 第1 :於避雷器元件層積體230的一部份之外周存在 有作爲接地體之機器殻體210，要使避雷器元件23 0a的 電壓分攤變得均勻，有其困難，因此，存在有其之適用被 限制於2 2 / 33kV程度之中壓用的線路之缺點。 第2:於此種插入型之避雷器中，需要於避雷器元件 層積體230的外周設置絕緣樹脂之模鑄體240，藉由使此 # 模鑄體240的外面密接於襯套220的插入孔之內面，來確 保模鑄體240的外面與襯套220的插入孔的內面間之面壓 ，以防止在界面之絕緣破壞β 第3:確保前述之模鑄體240的外面與襯套220的插 入孔之內面間的面壓之方法，雖知道有使絕緣樹脂的模鑄 體24 0的外面形狀配合襯套2 20的插入孔之內面形狀的方 法，但是，單單使絕緣樹脂的模鑄體240的外面形狀配合 襯套220的插入孔之內面形狀，而使其插入襯套220的插 入孔內之構造中，難於對模鑄體240的外面與襯套2 2 0的 (3) 1378475 插入孔之界面賦予有效的面壓。 第4:於此種插入型之避雷器中，在機器的耐電壓試 . 驗時，對避雷器元件層積體230施加超過該避雷器元件層 # 積體230的動作開始電壓之電壓的關係，需要於從襯套 220拆下避雷器元件層積體23 0之狀態下，而進行耐電壓 試驗，在將避雷器元件層積體230從襯套220拆下時，需 要藉由SF6與固體絕緣物等來絕緣襯套220的內部。 φ 第5:絕緣前述之襯套220內部的方法，知道有如第 18圖所示般，可裝卸自如地將與模鑄體240同形狀的絕 緣栓3 10裝置於襯套22 0的插入孔內之方法，但是，在此 種構造之絕緣栓310中，爲了不使襯套220的插入孔的內 面與絕緣栓3 1 0的外面間之界面產生間隙，需要使絕緣栓 310的外面形狀配合襯套22 0的插入孔之內面形狀，因此 ’有絕緣栓310大型化至必要以上之缺點，另外，在單單 使絕緣栓310的外面形狀配合襯套220的插入孔之內面形 # 狀的構造中，和前述的模鑄體240相同，難於對襯套220 的插入孔之內面與絕緣栓310的外面間之界面賦予有效的 面壓。 〔非專利文獻〗〕電氣學會技術報告 第8 5 1號7 (第2圖、第10) 〔專利文獻1〕日本專利特開平1-232681 (第I圖） 【發明內容】 〔發明所欲解決之課題〕 (4) 1378475 本發明係爲了解決前述缺點而完成者，目的在於提供 一種避雷器，該避雷器可提供：第1:不需要設置以往之 . 氣體絕緣桶型避雷器所有之切離裝置，可謀求使機器的構 . 造簡化、縮小化及輕量化、低成本化，第2:於進行耐電 壓試驗時，不需要將機器殼體內的絕緣氣體予以回收、加 以塡充之作業，第3:藉由謀求避雷器元件的電壓分攤之 均勻化，也可以適用於66/77kV級之高壓電路，第4: # 藉由確保襯套的插入孔內面與橡膠模鑄體外面間之面壓， 可以防止界面之絕緣破壞，第5:於避雷器元件層積體之 裝置時，可對避雷器元件間賦予特定的面壓，於機器之耐 電壓試驗時，可以容易地將避雷器元件層積體予以拆下， 第6:可將避雷器元件層積體容易地從主電路導體予以切 離，第 7:在對避雷器流過遠超過標稱放電電流之接地電 流時，產生於機殼內側構成體之激波不易傳播於襯套，所 以，可以防止氧化鋅元件與襯套之飛散，第8:可簡單地 • 進行漏電流之測定之避雷器及避雷器之漏電流的測定方法 〔解決課題之手段〕 本發明之第1形態的避雷器，其特徵爲：具備，於收 容電器之機器殼體的開口部，氣密地覆蓋前述開口部而配 設之襯套、及於前述襯套的插入孔內，可從前述機器殼體 的外部裝卸自如地裝著之避雷器模鑄體，前述避雷器模鑄 體，係具備：將複數個之避雷器元件予以層積而成之避雷 -9 - (5) 1378475 器元件層積體'及設置於前述避雷器元件層積體之外周的 絕緣模鑄體’前述避雷器模鑄體，係其全長被收容於前述 襯套的插入孔的內部。 本發明之第2形態’係於第1形態之避雷器中，前述 避雷器模鑄體係於被收容在前述襯套的插入孔之內部的狀 態下，藉由密封蓋而被密封。 本發明之第3形態，係於第1形態之避雷器中，前述 '# 絕緣模鑄體’係由絕緣橡膠之模鑄體所形成。 本發明之第4形態，係於第丨形態之避雷器中，前述 襯套，係以硬質的塑膠樹脂所形成。 本發明之第5形態’係於第丨形態之避雷器中，於前 述襯套的頂部，設置有連接於前述電器之主電路導體的主 電路連接件’於前述避雷器模鑄體的前端部，連接於前述 主電路連接件之連接導體和前述避雷器模鑄體設置成一體 〇 • 本發明之第6形態，係於第1形態之避雷器中，前述 避雷器模f春體’係具備：將以氧化鋅爲主成分之複數個的 避雷器元件予以層積而成之避雷器元件層積體 '及抵接於 前述避雷器元件層積體的高壓側之連接導體、及抵接於前 述避雷器元件層積體的低壓側之按壓固定架、及設置於前 述避雷器元件層積體之外周的絕緣模鑄體。 本發明之第7形態，係於第6形態之避雷器中，前述 避雷器模鑄體，係藉由設置於前述避雷器元件層積體的外 周之絕緣模鑄體而被一體化。 -10- (6) 1378475 本發明之第8形態，係於第3形態之避雷器中，前述 避雷器模鑄體，係於前述襯套的插入孔的內部，朝向前述 襯套的前端部而被按壓著。 本發明之第9形態，係於第8形態之避雷器中，於前 述避雷器模鑄體的後端部，配設有藉由軸方向的按壓而被 施附有彈簧力之後端側彈簧。 * 本發明之第1 〇形態，係於第8形態之避雷器中，前 述襯套之插入孔的內面，係具有從前述襯套的前端部朝向 後端部，擴展爲圓錐狀之推拔內面，前述絕緣模鑄體之外 面，係具有和前述推拔內面嵌合之推拔外面。 本發明之第1 1形態，係於第8形態之避雷器中，於 前述避雷器模鑄體的前端部，配設有藉由對軸方向之按壓 而被施附有彈簧力之前端側彈簧，於前述避雷器模鑄體的 後端部，配設有藉由對軸方向之按壓而被施附有彈簧力之 後端側彈簧。 • 本發明之第1 2形態，係於第1 1形態之避雷器中，前 述前端側彈簧的彈簧常數，係設定爲比前述後端側彈簧之 全體的彈簧常數爲低。 本發明之第1 3形態，係於第1形態之避雷器中，於 前述襯套的插入孔內，和前述避雷器模鑄體交換性地，從 前述機器殼體的外部裝卸自如地裝著有絕緣栓。 本發明之第1 4形態，係於第1 3形態之避雷器中，前 述絕緣栓係具備：裝著於前述襯套的插入孔內，於外面具 有和前述襯套的推拔內面嵌合之推拔外面的絕緣栓本體、 -11 - (7) 1378475 及裝著於前述襯套的插入孔內’使前述高壓屏蔽體和前述 絕緣栓本體的高壓側電極電性接觸之接觸構件、及裝著於 前述襯套的插入孔內，使前述絕緣栓本體朝前述襯套的前 端部側按壓之按壓構件。 本發明之第〗5形態’係於第]3形態之避雷器中，於 前述絕緣栓本體的後端面與前述按壓構件的前端面間，配 設有彈簧，前述彈簧係藉由前述按壓構件對前述襯套之前 端部方向之按壓，而被施附有彈簧力。 本發明之第1 6形態，係於第1形態之避雷器中，前 述避雷器模鑄體之前端部外周，係藉由高壓屏蔽體所覆蓋 〇 本發明之第]7形態，係於第]6形態之避雷器中，前 述襯套的後端部，係通過前述機器殼體的開口部而被導出 前述機器殼體的外部。 本發明之第1 8形態，係於第1 7形態之避雷器中，前 • 述避雷器元件層積體的中間部之電場，係藉由前述高壓屏 蔽體的後端部與前述機器殼體的內面間之間隔的調整而被 控制。 本發明之第1 9形態’係於第】6形態之避雷器中’前 述高壓屏蔽體的外周，係藉由絕緣性之阻障層所覆蓋。 本發明之第2 0形態’係於第1 6形態之避雷器中’前 述高壓屏蔽體，係具有和前述襯套的前端部之形狀略相同 形狀之固定架，前述固定架係被埋設於前述襯套的前端部 ，而和前述襯套成爲同心狀。 -12- (8) 1378475 本發明之第21形態’係於第16形態之避雷器中，前 述高壓屏蔽體，係以塗布於前述襯套的前端部外周之導電 性的塗布層所形成。 本發明之第22形態，係於第】6形態之避雷器中，前 述高壓屏蔽體係具有圓筒狀之固定架，前述固定架係包圍 前述襯套的前端部而配設於前述襯套的前端部之周圍。 本發明之第2 3形態，係於第1 6形態之避雷器中，於 # 前述高壓屏蔽體的外周，設置有固體絕緣層》 本發明之第2 4形態，係於第1形態之避雷器中，前 .述襯套的後端部’係通過前述機器殼體之開口部而被導出 前述機器殼體的外部。 本發明之第25形態，係於第24形態之避雷器中，於 前述襯套的後端部，從前述襯造之後端部端面至前述機器 殻體的外壁之部份設置有斷絕部。 本發明之第2 6形態，係於第2 5形態之避雷器中，前 Φ 述襯套之後端部，係以絕緣性的圓筒狀構件所形成。 本發明之第2 7形態之避雷器之漏電流測定方法，其 特徵爲：具備’第24形態至第26形態中任一形態的避雷 器’於構成前述避雷器之機器殼體、及構成前述避雷器之 避雷器元件層積體的低壓側間安裝接地線，來測定流經前 述接地線之電流。 本發明之第2 8形態，係於第1形態製第26形態中任 一形態之避雷器中，於前述避雷器模鑄體和前述襯套之插 入孔間，設置有氣體層。 -13- (9) 1378475 〔發明效果〕 如依據本發明之第1形態至第2 8形態之避雷器及避 雷器之漏電流測定方法，則有以下之效果。 第1:可將包含避雷器元件層積體之避雷器模鑄體從 機器機殻的外部，裝卸自如地裝著於氣密地安裝於機器機 ' 殻的開口部之襯套內，所以，不需要設置以往之氣體絕緣 φ 桶型避雷器所有之切離裝置，可以謀求機器構造的簡化、 縮小化及輕量化、低成本化，而且，於進行耐電壓試驗時 ，不需要將機器機殼內的絕緣氣體予以回收、加以塡充之 作業。 第2:藉由將襯造的後端部予以氣密地導出機器機殼 的外部，能把避雷器元件層積體的一部份（低壓側）導出 機器機殼的外部，可以謀求機器構造的簡化 '小型化及輕 量化。 # 第3:包含避雷器元件層積體之避雷器模鑄體係被裝 著於襯套內，且避雷器元件層積體的上端部側（高壓側） 之周圍係藉由埋設於上部圓筒部之屏蔽體所覆蓋’可以謀 求避雷器元件的電壓分攤之均勻化，進一步也可以適用於 66/ 77kV級之高壓線路。 第4:橡膠模鑄體爲朝向襯套的前端部而被按壓，得 以確保襯套的插入孔內面與橡膠模鑄體外面之間的面壓’ 可以防止在界面之絕緣破壞。 第5 :於避雷器模鑄體的後端部配設有後端側彈簧’ -14 - 1378475 do) 藉由對該後端側彈簧施附有彈簧力，可將避雷器模鑄體朝 向襯套的前端部而予以按壓。 第6 :藉由將前端側彈簧的彈簧常數設定爲比後端側 彈簧之全體彈簧常數還低’於避雷器模鑄體之裝著時’可 藉由後端側彈簧的整體之按壓力，而將避雷器模鑄體朝向 襯套的前端部按壓，另外’於避雷器模鑄體的拆下時’藉 ' 由解除後端側彈簧的按壓’可藉由前端側彈簧的彈簧力’ 'φ 而將避雷器模鑄體押出襯套的後端部側。 第7:藉由使橡膠模鑄體的推拔外面嵌合於襯套的推 拔內面，能使軸方向的按壓力有效作用爲面壓’而且’可 使兩者之界面中之絕緣性能提升。 第8:藉由後端側彈簧之彈簧力及前端側彈簧之彈簧 力的相乘效果，可對避雷器元件與連接導體間、避雷器元 件間、避雷器元件與按壓部間賦予特定的面壓。 第9:藉由進行機器之耐電壓試驗等時之密封蓋的拆 • 下，避雷器模鑄體藉由前端側彈簧之彈簧力而被押出襯套 的後端部側，可以容易地進行避雷器模鑄體的拆下。 第1〇:被導出機器機殼的外部之襯套的後端部，係 以環氧樹脂等之絕緣構件所形成’而且’於襯套內裝著有 包含避雷器元件之避雷器模鑄體’可以在機器機殼的外壁 與避雷器元件層積體的低壓側間設置斷絕部。 第1 1 :藉由於絕緣模鑄體與襯套的插入孔間設置空 氣、氮氣等之氣體層’可將遠超過標稱放電電流之接地電 流複數次流經避雷器’使避雷器元件破壞時所產生的激波 -15- (11) 1378475 ，透過氣體層而從襯套的密封部份之間隙等予以放出（釋 放電壓），進一步使該激波不易傳播於襯套，可以防止避 雷器元件之飛散。 第12:於進行機器之耐電壓試驗等之時，藉由於襯 套的插入孔內和避雷器模鑄體交換性地裝著特定構成之絕 緣栓，可以確保於拆下避雷器模鑄體之狀態中之襯套的插 ' 入孔內之絕緣，而且，藉由使絕緣栓位於電場集中之高壓 φ 屏蔽體的後端側端部的內側，可以有效地進行裝著有絕緣 栓之狀態中之電場的控制，另外，藉由只密封高壓屏蔽體 之後端側端部附近的內側，可以確保襯套之插入孔內的絕 緣，所以，能謀求絕緣栓之小型化。 第13:藉由代替以固定架所形成之高壓屛蔽體，而 設置導電性之塗布層，可以謀求避雷器之輕量化、低成本 化。 第14:藉由於圓筒狀之固定架的周圍配置絕緣性之 φ 阻障構件，可使相間的絕緣距離’或與機器機殼之絕緣距 離縮短，進一步可以謀求機器的縮小化。 第15:藉由使面壓能有效作用之推拔內面位於電場 集中之高壓屏蔽體的後端側端部之內側’可以防止在界面 之絕緣破壞。 第16:藉由於一體地設置於避雷器模鑄體的前端部 之連接導體，設置圓筒部’可以於該圓筒部容易地配設前 端側彈簧，另外，藉由於主電路連接件設置連接導體插入 部，可以於該連接導體插入部容易地插入配設有前端側彈 -16- (12) 1378475 簧之圓筒部。 另外，如依據本發明之第27形態之避雷器之漏電流 測定方法，可以於機器機殼之外壁與避雷器元件層積體的 低壓側間設置斷絕部，於機器機殼的外部中’藉由在被斷 絕之機器機殼的外壁與避雷器元件層積體之低壓側間安裝 接地線，可以簡單地測定避雷器元件層積體內的漏電流’ ' 進而，於測定漏電流時，不需要將機器機殼內的絕緣氣體 'φ 予以回收、加以塡充之作業，另外’機器機殻內不需要配 設絕緣器，所以，可以謀求機器的小型化、簡化及輕量化 、低成本化。 【實施方式】 以下，參照圖面說明適用本發明之避雷器之合適的實 施形態例。另外，在以下之說明中，所謂避雷器模鑄體的 「前端部」、避雷器元件層積體的「前端部」、襯套的「 • 前端部」，係指避雷器模鑄體、避雷器元件層積體、襯套 個別之高壓側的端部，爲相當於圖中之上方向。另外，避 雷器模鑄體的「後端部」、避雷器元件層積體的「後端部 」、襯套的「後端部」，係指與前端部相反側之端部，相 當於圖中之下方向。 〔實施例1〕 第1圖係表示66 / 7 7kV級之本發明的避雷器之一例 的一部份剖面圖 -17- (19) 1378475 成只兩者的間隔變寬之構造中，難於使避雷器元件61a之 電壓分攤變得均勻。此點在本實施例中，藉由使避雷器元 件層積體61的前端部（6 1之1/3程度的長度）及中間 部（避雷器元件層積體61之1/3程度之長度）位於機器 機殼1內，使避雷器元件層積體61的後端部（避雷器元 件層積體61的1/3程度之長度）位於機器機殼1之外部 ’高壓模鑄體4與作爲接地體之機器機殻1的間隔被適當 ' φ 地調整，能適當地控制避雷器元件層積體61之中間部中 之電場，進而能謀求避雷器元件61a之電壓分攤的均勻化 〇 如前述般，如依據此種構造之避雷器，第1:可於氣 密地安裝於機器機殻1之開口部la的襯套2內，從機器 機殼i的外部能裝卸自如地裝著避雷器元件層積體61， 所以，不需要設置以往之氣體絕緣桶型避雷器所有之切離 裝置，可使機器的構造簡化，第2:進行耐電壓試驗時， # 不需要將機器機殼1內的絕緣氣體予以回收、加以塡充之 作業，第3:藉由使避雷器元件層積體61的一部份（低 壓側）導出於機器機殼】的外部’可以謀求機器的縮小化 ，第4:藉由將包含避雷器元件層積體61之避雷器模鑄 體6裝著於襯套2內’避雷器元件層積體61的上端部側 (高壓側）的周圍藉由埋設於上部圓筒部51之屏蔽本體 41所覆蓋，可以謀求避雷器元件之電壓分攤的均勻 化，進而也可以適用於66/77kV級之高壓線路’第5: 橡膠模鑄體係朝襯套的前端部而被按壓’可確保襯套的插 -24- (20) 1378475 入孔內面與橡膠模鑄體外面之間的面壓，能防止在界面之 絕緣破壞，第6:於避雷器模鑄體6的後端部配設有後端 側彈簧66，藉由對該後端側彈簧66付以彈簧力，可將避 雷器模鑄體6朝襯套2的前端部按壓，第7:藉由使橡膠 模鑄體67的推拔外面嵌合於襯套2的推拔內面，可使軸 方向的按壓力有效作用爲面壓，即藉由對橡膠模鑄體67 ' 的圓錐狀部67b與附推拔插入孔53c的內周面間之界面賦 * φ 予特定的面壓，可使兩者之界面中之絕緣性能提升，第8 :藉由後端側彈簧66的彈簧力及前端側彈簧63之彈簧力 的相乘效果，可對避雷器元件61a與連接導體62間、避 雷器元件6 1 a間、避雷器元件6 1 a與按壓部65b間賦予特 定的面壓，第9:於進行機器之耐電壓試驗等時，藉由密 封蓋F之拆下，避雷器模鑄體6藉由前端側彈簧63之彈 簧力，被押出襯套2的後端部側，可以容易地進行避雷器 模鑄體6之拆下。 〔實施例2〕 第4圖係表示本發明之第2實施例中之避雷器的一部 份剖面圖。另外，該圖中，對與第I圖共通的部份賦予相 同符號，省略詳細之說明。 於此實施例中，藉由以環氧樹脂等之絕緣性材料來形 成襯套2，於導出於機器機殼1的外部之襯套2的後端部 形成有斷絕部Z。具體而言’於從絕緣性之圓筒狀構件之 下部圓筒部52的後端部端面至機器機殼1的外壁的部份 -25- (22) 1378475 〔實施例3〕 第5(a)圖係本發明之第3實施例中之避雷器的一 部份剖面圖，第5(b)圖係表示該實施例中之密封蓋的 平面圖。另外，在該圖中，對與第1圖共通的部份賦予相 同符號，省略詳細之說明。 第5 ( a )圖中，避雷器模鑄體6係具備：將以氧化 ' 鋅爲主成分之複數個避雷器元件61a加以層積所成之避雷 -φ 器元件層積體61、及配設於避雷器元件層積體61的前端 部側（高壓側）之連接導體62、及配設於避雷器元件層 積體6 1的後端部側（低壓側）之圓柱狀的按壓固定架64 '及涵蓋連接導體62以及按壓固定架64而一體地模鑄於 避雷器元件層積體6〗的外周之由矽橡膠等所成之絕緣模 鑄體67d，絕緣模鑄體67d與襯套2的插入空間設置有氣 體層G。 前述絕緣模鑄體67d爲了使避雷器元件層積體61、 # 連接導體62及按壓固定架64成爲一體化而設爲具有充分 之厚度，在使該厚度薄至可及之範圍，於將避雷器模鑄體 6收容於襯套2內部之狀態下，於避雷器模鑄體6與襯套 2的插入孔（上部插入孔51a、附推拔插入孔53a、下部 插入孔52a)間形成氣體層G。另外，藉由將此種絕緣模 鑄體6 7d設置於避雷器元件層積體61的外周，可以緩和 避雷器元件層積體61的外表面之電場。 此處，絕緣模鑄體67d也可代替藉由矽橡膠之模鑄體 ’而以環氧樹脂等之橡膠、塑膠樹脂之模鑄體來形成。另 -27- (25) 1378475 〔實施例4〕 第7圖係表示於進行機器之耐電壓試驗時，與前述的 避雷器模鑄體6交換性地可裝卸自如地裝著於襯套內之絕 緣栓的一部份剖面圖。另外，於該圖中，對與第〗圖及第 2圖共通部份賦予相同符號，省略詳細之說明。 第7圖中，本發明中之絕緣栓20係具備：裝著於襯 ' φ 套2的附推拔插入孔53a內之絕緣栓本體21、及位於絕 緣栓本體21的上方，且與上部圓筒部51同心狀地裝著於 襯套2的上部插入孔51a內之圓筒狀連接構件22、及位 於絕緣栓本體21的下方，且與下部圓筒部52同心狀地裝 著於襯套2的下部插入孔5 2a內之上端閉鎖之圓筒狀按壓 構件23。此處，接觸構件22係以鋁合金等之金屬所形成 ，其外徑設爲比襯套的上部插入孔的口徑還小徑，另外， 其軸方向之長度係設爲與高壓模鑄體4的頂部內壁41b及 # 後述之高壓側電極27的上壁27b間的間隔相等之長度。 具體而言，接觸構件22的軸方向之長度係設爲：在絕緣 栓20裝著於襯套2內之正規位置的狀態下，接觸構件22 的前端部與高壓模鑄體4的頂部內壁41b電性接觸，後端 部與高壓側電極27的上壁2 7b電性接觸之長度。另外， 按壓構件23係以鋁合金等之金屬所形成，於圓筒部的一 部份，沿著軸方向設置有厚板部23a。進而，於按壓構件 23的閉鎖部23b設置有沿著圓周方向等間隔配置之複數 個螺絲插通孔23c，於厚板部23a的後端面因應需要而設 -30- (26) 1378475 置有螺絲孔23d❶ 絕緣栓本體2]係具備：具有與襯套2的下部插入孔 52a之口徑略同直徑之外徑的圓柱狀部24、及連接於該圓 柱狀部24的前端部，而配置於襯套2的附推拔插入孔 53a之圓錐狀部25、及埋設於圓柱狀部24的後端部，使 球面狀凸部26a朝向前端部之半球狀的低壓側電極26、 _ 及埋設於圓錐狀部25的前端部，而使球面狀凸部27a與 ' φ 低壓側電極26面對之半球狀高壓側電極27。 此處，圓錐狀部25的外面係具有與襯套2的推拔內 面53b嵌合之推拔外面25a，另外，低壓側電極26的直 徑係設爲比圓柱狀部24的直徑稍微小徑，進而，其之下 端面係被埋設爲和圓柱狀部24的下端面爲同一面，於該 低壓側電極26的下端面設置有沿著圓周方向等間隔配置 之複數個彈簧收容孔2 6b與複數個螺絲孔2 6 c。 圓柱狀部24及圓錐狀部25係由乙烯丙烯橡膠等之絕 # 緣材料所形成，與低壓側電極2 6及高壓側電極2 7模鑄爲 一體。 接著，說明將如此構成之絕緣栓20可裝卸自如地裝 著於襯套2內之方法。 首先’拆下第1圖所示之螺絲V 2，從襯套2的下部 圓筒部52拆下密封蓋F，且從襯套2拆下避雷器模鑄體6 〇 接著’如第7圖所示般，於低壓側電極2 6的彈簧收 容孔26b配置彈簧28，使其下半部從彈簧收容孔26b突 -31 - (28) 1378475 耐電壓試驗等時，藉由和避雷器模鑄體6交換性地於襯套 2的插入孔內裝著絕緣栓20，可以確保在拆下避雷器模鑄 體6之狀態中的襯套2之插入孔內的絕緣。另外，藉由使 絕緣栓20位於電場集中之高壓模鑄體4的後端側端部的 內側，可以有效地進行裝著有絕緣栓20之狀態中之電場 的控制，進而，還藉由只密封高壓模鑄體4的後端側端部 ' 附近之內側，可以確保襯套2的插入孔內之絕緣，能謀求 ' φ 絕緣栓20的小型化。 〔實施例5〕 第9圖係表示本發明之第實施例中之避雷器的一部份 剖面圖。另外，該圖中，對和第】圖共通之部份賦予相同 符號，省略詳細之說明。 第9圖中，關於此實施例，係於襯套7的前端部之外 周面，如虛線所示般，設置有導電性的塗布層75。 # 此處，第5實施例中之襯套7係具備：於其本身的上 面之外周緣附近設置有環狀的凹陷部 71a之中間圓筒部 7 1 '及與中間圓筒部7 1同心狀地連接於中間圓筒部7 1的 上端部，具有比中間圓筒部71之外徑更小徑，且前端細 狀之緣追狀部7 2a，上端部被閉鎖之上部圓筒部72、及與 中間圓筒部71同心狀地連接於中間圓筒部7 1之下面的外 周緣附近’比中間圓筒部71的外徑更小徑的下部圓筒部 73、及使其本身的前端部從閉鎖部72b突出，而埋設於上 部圓筒部72的閉鎖部72b的中央部之主電路連接件74。 -33- (30) 1378475 〔實施例6〕 第11圖係表示本發明之第6實施例中之避雷器的一 部份剖面圖。另外，該圖中，對與第丨圖共通之部份賦予 相同符號，省略詳細之說明。 第Π圖中，關於此實施例，係於襯套8的前端部載 置 '固定有另一個體之高壓屏蔽體10。 ' 此處，第6實施例中之襯套8係具備：前端細狀之中 'φ 間圓筒部8 1 '及與中間圓筒部8 1同心狀地連接於中間圓 筒部81的上端部，比中間圓筒部81的外徑更小徑之上部 圓筒部82、及與中間圓筒部81同心狀地連接於中間圓筒 部81的下端部，且與中間圓筒部81的下端部外徑略相同 直徑之下部圓筒部83，於下部圓筒部83的前端部位置之 外周連設有環狀之安裝凸緣83a» 高壓屏蔽體10係具備：上端閉鎖之圓筒狀之金屬件 1 1、及從閉鎖部〗2朝上立設於金屬件1 1的閉鎖部12中 φ 央之主電路連接件13。 此種構造之高壓屏蔽體10係如圖所示般，將主電路 連接件13配置於上部圓筒部82之上方位置，金屬件11 的側壁部1 4位於上部圓筒部82之側壁部82a的周圍，而 和上部圓筒部82同心狀地載置 '固定於上部圓筒部82的 前端部。 第12圖係表示第6實施例中之避雷器的電位分布。 根據該圖，於此實施例中，和第〗實施例中之避雷器相同 ，避雷器元件層積體61的前端部係藉由構成高壓屏蔽體 -35- (31) 1378475 】〇之圓筒狀的金屬件11所遮蔽，所以，電場不集中於該 前端部’另外’避雷器元件層積體61的後端部係配設於 作爲接地體之機器殼體1的外部，電場也不集中於該後端 部’進而’避雷器元件層積體6]的中間部係藉由圓筒狀 的金屬件1 1與作爲接地體之機器殻體1間的間隔之調整 ’電場受到控制’所以，知道電場也不會集中於該中間部 〇 φ 如前述般，於第6實施例中之避雷器中，整體而言， 可以使避雷器元件61a之電壓分攤均勻化。另外，此實施 例中之避雷器可以適用於油絕緣、氣體絕緣或空氣絕緣型 之電器。 〔實施例7〕 第13圖係表示本發明之第7實施例中之避雷器的一 部份剖面圖。另外，該圖中’對與第1圖及第圖共通 • 的部份賦予相同符號’省略詳細之說明。 第13圖中，關於此實施例，於襯套9的前端部載置 、固定有第Π圖所示之高壓屏蔽體1〇°另外’如下述般 ，高壓屏蔽體10的周圍被以絕緣性之阻障器9115所覆蓋。 此處，第7實施例中之襯套9係具備=於其本身上面 之外周緣附近設置有環狀之凹陷部91a之上部圓筒部91 、及與上部圓筒部91同心狀地連接於上部圓筒部91的下 端部，且比上部圓筒部9 1的外徑更小徑之下部圓筒部92 β然後，與第11圖所不者相同構造的咼壓屏蔽體]〇，其 -36- (32) 1378475 側壁部1 4係與上部圓筒部9 1同心狀地配設，使得位於上 部圓筒部91的凹陷部91a內。另外，此實施例中之襯套 9係設爲上部圓筒部91的外徑比機器殼體1的開口部la 更大徑，上部圓筒部91的外周緣的下面係氣密地載置、 固定於機器殼體〗的內面。 第14圖係表示第7實施例中之避雷器的電位分布。 ' 根據該圖，於此實施例中，也和第1實施例中之避雷器相 * φ 同，避雷器元件層積體61的前端部係藉由作爲高壓屏蔽 體之圓筒狀的金屬件U而被遮蔽，電場不集中於該前端 部，另外，避雷器元件層積體6 1的後端部係配設於作爲 接地體之機器殼體1的外部，電場也不集中於該後端部， 進而，避雷器元件層積體61的中間部係藉由圓筒狀的金 屬件11與作爲接地體之機器殼體〗間的間隔之調整，電 場受到控制，知道電場也不集中於該中間部。 如前述般，於第7實施例中之避雷器中，整體而言， # 可以使避雷器元件層積體61之電壓分攤均勻化。另外， 於此實施例中之避雷器中，高壓屏蔽體10的側壁部14係 配設於上部圓筒部91的凹陷部91a，成爲於圓筒狀的金 屬件]1的周圍配置有絕緣性之阻障構件91b，所以，可 使相間之絕緣距離 '或者與機器殼體1之絕緣距離變短， 進而，可以謀求機器的小型化。另外，此實施例中之避雷 器可以適用於油絕緣、氣體絕緣或空氣絕緣形式之電器。 〔實施例8〕 -37- (34) 1378475 避雷器元件61a的電壓分攤均勻化》 另外，於第8實施例中，雖就將高壓屏蔽體20埋設 於橡膠模鑄體67之情形而做說明，但是，該髙壓屏蔽體 20也可以配設於橡膠模鑄體67的外周。 〔產業上之利用可能性〕 本發明在申請專利範圍內，如下述般，可以變更、修 ' φ 正。 第1:於前述實施例中，雖就於機器殼體1的底部配 設襯套之情形來作說明，但是，也可以於機器殼體1的側 壁配設襯套。 第2:於前述實施例中，雖就66/ 77kV之高壓線路 適用本發明之避雷器的情形來作說明，但是，於低於 6 6kV之線路或超過77kV之高壓線路，也可以使用本發明 之避雷器。 【圖式簡單說明】 第1圖係本發明之第1實施例中之避雷器的一部份剖 面圖。 第2圖係本發明之第1實施例中之避雷器模鑄體之— 部份剖面圖。 第3圖係本發明之第丨實施例中之避雷器的等電位分 布圖。 第4圖係本發明之第2實施例中之避雷器的一部份剖 -39- (35) 1378475 面圖》 第5圖係本發明之第3實施例中之避雷器的一部份剖 面圖。 第6圖係本發明之第3實施例中之避雷器的等電位分 布圖。 第7圖係本發明之第4實施例中之絕緣栓的一部份剖 面圖。 • 第8圖係本發明之第4實施例中之絕緣栓的等電位分 布圖。 第9圖係本發明之第5實施例中之避雷器的一部份剖 面圖。 第〗〇圖係本發明之第5實施例中之避雷器的等電位 分布圖。 第Π圖係本發明之第6實施例中之避雷器的一部份 剖面圖。 # 第12圖係本發明之第6實施例中之避雷器的等電位 分布圖。 第13圖係本發明之第7實施例中之避雷器的_部份 剖面圖。 第14圖係本發明之第7實施例中之避雷器的等電位 分布圖。 第15圖係本發明之第8實施例中之避雷器的一部份 剖面圖。 第1 6圖係以往之避雷器的一部份剖面圖。 -40- (36) (36)1378475 第1 7圖係以往之避雷器的一部份剖面圖。 第I 8圖係以往之絕緣栓的一部份剖面圖。 【主要元件符號說明】 1 :機器殼體 ]a :開口部 2 :襯套 3 :襯套本體 4 :高壓屏蔽體 6 :避雷器模鑄體 1 1 :圓筒狀之金屬件 20 :絕緣栓 2 1 :絕緣栓本體 2 2 :接觸構件 2 3 :按壓構件 4 1 :屏蔽本體 4 1 a :側壁部 42 :連接導體插入部 .43 :主電路連接件 5 1 :上部圓筒部 5 1 a :上部插入孔 5 1 b :閉鎖部 5 2 :下部圓筒部 5 2 a :下插入孔 -41 - (37) 1378475 52b :安裝凸緣 5 3 :中間圓筒部 5 3 a :附推拔插入孔 53b :推拔內面 61 :避雷器元件層積體 6 1 a :避雷器元件 62 :連接導體 φ 6 3 :前端側彈簧 65b :環狀構件 66 :後端側彈簧 6 7 a :小徑部 67b :圓錐狀部 67c :推拔外面 6 7 d :大徑部 6 7 :橡膠模鑄體（絕緣模鑄體） • 67d :絕緣模鑄體 7 5 :導電性之塗布層 9 1 b :絕緣性之阻障器 F :密封蓋 G :氣體層 N :螺絲孔 P1 : 0型環 V 1 :螺絲 V 2 :螺絲 -42-Lightning protection must be applied to the voltage withstand test of the insulated switchgear (hereinafter referred to as "GIS (Gas Insulated Switchgear)". The device element laminate 1 is cut away from the main circuit conductor (not shown). Therefore, it is necessary to provide a cutting device (not shown), and therefore, there is a drawback that the structure of the machine becomes complicated. On the other hand, in the latter arrester, it is not necessary to provide a relationship of the cutting device, the structure can be simplified, and when the withstand voltage test is performed, the insulating gas in the machine casing 210 can be recovered and charged. The work is not required, but there are the following disadvantages. First, there is a machine casing 210 as a grounding body in a part of the outer portion of the arrester element laminate 230. It is difficult to evenly distribute the voltage of the arrester element 230a. Therefore, there is a problem. The disadvantages of the line that is limited to the pressure of 2 2 / 33kV are applicable. Secondly, in the insertion type arrester, it is necessary to provide the molded body 240 of the insulating resin on the outer circumference of the arrester element laminate 230, and the outer surface of the # molded body 240 is in close contact with the insertion hole of the bush 220. The inner surface ensures the surface pressure between the outer surface of the molded body 240 and the inner surface of the insertion hole of the bushing 220 to prevent insulation damage at the interface. #3: Ensure the outer surface of the molded body 240 and the bushing. In the method of the surface pressure between the inner surfaces of the insertion holes of the 220, it is known that the outer shape of the molded body of the insulating resin is matched with the shape of the inner surface of the insertion hole of the bushing 210, but the insulating resin is simply used. The outer shape of the molded body 240 fits into the inner surface shape of the insertion hole of the bushing 220, and is inserted into the insertion hole of the bushing 220, which is difficult for the outer surface of the molded body 240 and the bushing 2 2 0 (3) 1378475 The interface of the insertion hole gives an effective surface pressure. No. 4: In this type of plug-in type arrester, the withstand voltage test of the machine. In the test, the relationship between the voltage of the operation start voltage of the arrester element layer body 230 and the voltage of the operation start voltage of the arrester element layer 230 is required to be removed from the bushing 220 while the arrester element laminate 23 0 is removed. In the withstand voltage test, when the arrester element laminate 230 is detached from the bush 220, it is necessary to insulate the inside of the bush 220 by SF6, a solid insulator or the like. Φ 5: a method of insulating the inside of the bushing 220, as shown in Fig. 18, detachably inserting the insulating plug 3 10 having the same shape as the molded body 240 into the insertion hole of the bushing 22 0 However, in the insulating plug 310 of such a configuration, in order not to cause a gap between the inner surface of the insertion hole of the bushing 220 and the outer surface of the insulating plug 310, it is necessary to match the outer shape of the insulating plug 310. The shape of the inner surface of the insertion hole of the bushing 22 0 is such that the insulating plug 310 is enlarged to the extent necessary, and the outer shape of the insulating plug 310 is simply fitted to the inner surface of the insertion hole of the bushing 220. In the same configuration as the above-described molded body 240, it is difficult to impart an effective surface pressure to the interface between the inner surface of the insertion hole of the bushing 220 and the outer surface of the insulating plug 310. [Non-Patent Document] Electrical Engineering Technical Report No. 8 5 No. 1 (Fig. 2, 10) [Patent Document 1] Japanese Patent Laid-Open No. 1-232681 (Fig. 1) [Summary of the Invention] (4) 1378475 The present invention has been made to solve the aforementioned drawbacks, and an object of the invention is to provide a lightning arrester which can provide: No. 1: no need to set up the past. Gas-insulated barrel arresters are all cut-off devices that can be used to build the machine. Simplification, reduction, light weight, and low cost. 2nd: When performing the withstand voltage test, it is not necessary to collect and refill the insulating gas in the machine casing. Third: By seeking the arrester component Homogenization of voltage sharing can also be applied to high-voltage circuits of 66/77kV class. No. 4: # Insulation damage of the interface can be prevented by ensuring the surface pressure between the inner surface of the insertion hole of the bushing and the outer surface of the rubber molded body. Fifth: When the device of the arrester element laminate is used, a specific surface pressure can be applied between the arrester elements, and the arrester element laminate can be easily removed during the withstand voltage test of the machine. The arrester element laminate is easily separated from the main circuit conductor. Step 7: When the arrester flows a ground current far exceeding the nominal discharge current, the shock generated on the inner side of the casing is less likely to propagate to the bushing. Therefore, it is possible to prevent scattering of the zinc oxide element and the bushing, and the eighth method of measuring the leakage current of the arrester and the arrester which can easily measure the leakage current. A lightning arrester according to a first aspect of the invention includes a bushing that is disposed in an opening of a machine casing that houses an electric appliance, a bush that is disposed to cover the opening in an airtight manner, and an insertion hole in the bushing, and is provided in the machine The arrester molded body is detachably attached to the outside of the casing, and the arrester molded body includes a lightning protection device in which a plurality of arrester elements are laminated. 9 - (5) 1378475 device component laminate And an insulating molded body of the above-described arrester molded body provided on the outer periphery of the arrester element laminate, the entire length of which is accommodated in the insertion hole of the bush. According to a second aspect of the present invention, in the lightning arrester of the first aspect, the arrester molding system is sealed by a sealing cover while being housed inside the insertion hole of the bush. According to a third aspect of the present invention, in the lightning arrester of the first aspect, the '#insulating molded body' is formed of a molded body of an insulating rubber. According to a fourth aspect of the present invention, in the lightning arrester of the first aspect, the bushing is formed of a hard plastic resin. According to a fifth aspect of the present invention, in the lightning arrester of the first aspect, a main circuit connector 'connected to a main circuit conductor of the electric appliance is provided at a top end of the bushing at a front end portion of the arrester molded body, and is connected The connection conductor of the main circuit connector and the lightning arrester molded body are integrally provided. According to a sixth aspect of the present invention, in the lightning arrester of the first aspect, the lightning arrester module f spring body is provided with zinc oxide a arrester element laminate formed by stacking a plurality of arrester elements as a main component, and a connection conductor that abuts on the high voltage side of the arrester element laminate and a low voltage that abuts against the arrester element laminate The side pressing fixture and the insulating molded body provided on the outer periphery of the arrester element laminate. According to a seventh aspect of the invention, in the lightning arrester of the sixth aspect, the lightning arrester molded body is integrated by an insulating molded body provided on an outer periphery of the arrester element laminate. In a lightning arrester according to a third aspect of the present invention, the lightning arrester molded body is pressed into a front end portion of the bushing inside the insertion hole of the bushing. With. According to a ninth aspect of the present invention, in the arrester of the eighth aspect, the end portion of the arrester molded body is provided with a spring force after the spring force is applied by pressing in the axial direction. According to a first aspect of the present invention, in the lightning arrester of the eighth aspect, the inner surface of the insertion hole of the bush has a conical shape extending from a front end portion toward a rear end portion of the bush The outer surface of the insulating molded body has a push-out outer surface that is fitted to the push-pull inner surface. According to a first aspect of the present invention, in the lightning arrester of the eighth aspect, the end portion of the arrester molded body is provided with an end-side spring that is applied with a spring force by pressing in the axial direction. The rear end portion of the arrester molded body is provided with an end side spring to which a spring force is applied by pressing against the axial direction. According to a first aspect of the invention, in the lightning arrester of the first aspect, the spring constant of the distal end side spring is set to be lower than a spring constant of the entire rear end side spring. According to a first aspect of the present invention, in the lightning arrester according to the first aspect of the present invention, in the insertion hole of the bushing, the insulator is detachably attached to the outside of the machine casing in exchange with the arrester molded body. bolt. According to a fourth aspect of the present invention, in the lightning arrester of the first aspect, the insulating plug is provided in an insertion hole of the bushing, and has an outer surface that is fitted to the inner surface of the bush Pushing the outer insulating plug body, -11 - (7) 1378475, and the contact member mounted in the insertion hole of the bushing to electrically contact the high voltage shield and the high voltage side electrode of the insulating plug body, and The pressing member that presses the insulating plug body toward the front end side of the bushing in the insertion hole of the bushing. According to a fifth aspect of the present invention, in the lightning arrester of the third aspect, a spring is disposed between a rear end surface of the insulating plug main body and a front end surface of the pressing member, and the spring is biased by the pressing member The bushing is pressed in the direction of the front end and is applied with a spring force. According to a first aspect of the present invention, in the lightning arrester according to the first aspect, the outer periphery of the front end portion of the arrester molded body is covered by the high-pressure shield, and the seventh aspect of the present invention is in the form of the sixth aspect. In the lightning arrester, the rear end portion of the bushing is led out of the outer casing of the machine casing through the opening of the machine casing. According to a thirteenth aspect of the present invention, in the lightning arrester of the seventh aspect, an electric field in an intermediate portion of the front body of the arrester element is formed by a rear end portion of the high-voltage shield and the inside of the machine casing The adjustment of the interval between the faces is controlled. The ninth aspect of the present invention is based on the outer periphery of the high-voltage shield of the sixth embodiment. The outer periphery of the high-voltage shield is covered with an insulating barrier layer. According to a second aspect of the present invention, in the lightning arrester of the first aspect, the high-pressure shield has a fixing frame having a shape slightly the same as a shape of a front end portion of the bushing, and the fixing frame is embedded in the lining. The front end of the sleeve is concentric with the bushing. In the lightning arrester according to the sixteenth aspect, the high-pressure shield is formed of a conductive coating layer applied to the outer periphery of the front end portion of the bush. According to a twenty-fourth aspect of the present invention, in the lightning arrester of the sixth aspect, the high-pressure shielding system has a cylindrical fixing frame, and the fixing frame surrounds a front end portion of the bushing and is disposed at a front end portion of the bushing Around it. According to a second aspect of the present invention, in the lightning arrester of the first aspect, the solid insulating layer is provided on the outer circumference of the high-voltage shield. The second aspect of the present invention is the lightning arrester according to the first aspect. Before . The rear end portion of the bushing is led out of the outer casing of the machine casing through the opening of the machine casing. According to a twenty-fifth aspect of the invention, in the lightning arrester of the twenty-fourth aspect, the end portion of the bushing is provided with a cut-off portion from a portion of the end surface after the lining to an outer wall of the machine casing. According to a twenty-sixth aspect of the present invention, in the lightning arrester according to the twenty-fifth aspect, the rear end portion of the front bushing is formed of an insulating cylindrical member. A method for measuring a leakage current of a lightning arrester according to a second aspect of the present invention is characterized in that: the lightning arrester of any one of the twenty-fourth to twenty-sixth aspects is provided in a device casing constituting the lightning arrester, and a lightning arrester constituting the lightning arrester A ground line is installed between the low voltage sides of the element laminate to measure the current flowing through the ground line. According to a second aspect of the invention, in the lightning arrester according to any one of the twenty-eighth aspect, the gas barrier is provided between the lightning arrester molded body and the insertion hole of the bush. [13] (9) 1378475 [Effect of the Invention] The method for measuring the leakage current of the arrester and the arrester according to the first to eighth aspects of the present invention has the following effects. First, the arrester molded body including the arrester element laminate can be detachably attached to the bushing of the opening of the machine casing from the outside of the machine casing, so that it is not required By setting up all the cutting devices for the conventional gas-insulated φ barrel-type arrester, it is possible to simplify, reduce, reduce, and reduce the cost of the machine structure. Moreover, it is not necessary to insulate the inside of the machine casing during the withstand voltage test. The gas is recovered and replenished. Second: By evacuating the rear end portion of the lining to the outside of the machine casing, a part (low-pressure side) of the arrester element laminate can be led out of the machine casing, and the machine structure can be realized. Simplify 'small size and light weight. #3: The arrester molding system including the arrester element laminate is housed in the bushing, and the periphery of the upper end side (high voltage side) of the arrester element laminate is shielded by the upper cylindrical portion. The coverage of the body can be used to equalize the voltage sharing of the arrester components, and can also be applied to the high voltage lines of the 66/77kV class. Fourth, the rubber molded body is pressed toward the front end portion of the bushing to ensure the surface pressure between the inner surface of the insertion hole of the bushing and the outer surface of the rubber molded body, thereby preventing insulation breakdown at the interface. No. 5: a rear end side spring is provided at the rear end portion of the arrester molded body ' -14 - 1378475 do) By applying a spring force to the rear end side spring, the arrester molded body can be oriented toward the bushing Press the front end. No. 6: by setting the spring constant of the front end side spring to be lower than the total spring constant of the rear end side spring 'when the arrester molded body is mounted', the entire pressing force of the rear end side spring can be used, and The arrester molded body is pressed toward the front end portion of the bushing, and 'when the arrester molded body is removed', the 'pressing of the rear end side spring' can be released by the spring force of the front end side spring ' 'φ The arrester molded body pushes out the rear end side of the bushing. Chapter 7: By fitting the push-out outer surface of the rubber molded body to the push-out inner surface of the bushing, the pressing force in the axial direction can be effectively applied as the surface pressure 'and' the insulation property in the interface between the two Upgrade. Eighth: By the synergistic effect of the spring force of the rear end side spring and the spring force of the front end side spring, a specific surface pressure can be given between the lightning arrester element and the connecting conductor, between the arrester element, and between the lightning arrester element and the pressing portion. No. 9: When the sealing cover of the machine is subjected to a withstand voltage test or the like, the arrester molded body is pushed out of the rear end side of the bush by the spring force of the front end side spring, and the arrester mode can be easily performed. The cast body is removed. The first step: the rear end portion of the bushing that is led out of the machine casing is formed of an insulating member such as epoxy resin, and 'the arrester molded body containing the arrester element is housed in the bushing'. A cutting portion is provided between the outer wall of the machine casing and the low pressure side of the arrester element laminate. The first one is that a gas layer of air, nitrogen, or the like is provided between the insulating mold body and the insertion hole of the bushing, and a ground current far exceeding the nominal discharge current can flow through the arrester multiple times to cause the arrester element to be broken. The shock wave -15-(11) 1378475 is released from the gap of the sealed portion of the bush through the gas layer (release voltage), and further the shock wave is less likely to propagate to the bushing, and the scattering of the arrester element can be prevented. In the case of performing the withstand voltage test of the machine, etc., it is possible to ensure that the arrester molded body is removed in a state in which the insulating plug of a specific configuration is exchanged in the insertion hole of the bushing and the arrester molded body. The bushing is inserted into the hole and insulated in the hole, and by placing the insulating plug on the inner side of the rear end side end portion of the high voltage φ shield concentrated by the electric field, the electric field in the state in which the insulating plug is mounted can be effectively performed. In addition, by sealing only the inner side in the vicinity of the end portion of the end portion of the high-pressure shield, the insulation in the insertion hole of the bush can be ensured, so that the size of the insulating plug can be reduced. Thirteenth: By providing a conductive coating layer instead of the high-pressure shielding body formed by the holder, it is possible to reduce the weight and cost of the arrester. Fifteenth: By providing an insulating φ barrier member around the cylindrical holder, the insulation distance between the phases or the insulation distance from the machine casing can be shortened, and the machine can be further reduced. In the fifteenth aspect, the dielectric breakdown at the interface can be prevented by causing the surface pressure to be effectively applied to the inner side of the rear end portion of the high-voltage shield where the electric field is concentrated. Sixteenth: The connecting portion conductor integrally provided at the front end portion of the arrester molded body is provided with a cylindrical portion 'the front end side spring can be easily disposed in the cylindrical portion, and the connecting conductor is provided by the main circuit connecting member In the insertion portion, a cylindrical portion in which a distal end side elastic - 16 - (12) 1378475 spring is disposed can be easily inserted into the connecting conductor insertion portion. Further, according to the leakage current measuring method of the arrester according to the twenty-seventh aspect of the present invention, the severing portion may be provided between the outer wall of the machine casing and the low-pressure side of the arrester element laminate, and the outside of the machine casing A grounding wire is installed between the outer wall of the machine casing that has been cut off and the low-voltage side of the arrester component laminate, so that the leakage current in the lining of the arrester component can be easily measured. Further, when measuring the leakage current, the machine casing is not required. The insulating gas 'φ in the inside is recovered and filled, and the insulator is not required in the machine casing. Therefore, the size, simplification, weight reduction, and cost reduction of the machine can be achieved. [Embodiment] Hereinafter, a preferred embodiment of a lightning arrester to which the present invention is applied will be described with reference to the drawings. In the following description, the "front end portion" of the arrester molded body, the "front end portion" of the arrester element laminate, and the "front end portion" of the bushing are referred to as the arrester molded body and the arrester component layer. The ends of the high-pressure side of the body and the bush are equivalent to the upper direction in the figure. In addition, the "rear end portion" of the arrester molded body, the "rear end portion" of the arrester element laminate, and the "rear end portion" of the bushing refer to the end portion opposite to the front end portion, which corresponds to the figure. Down direction. [Embodiment 1] Fig. 1 is a partial cross-sectional view showing an example of a lightning arrester of the present invention of the 66/7 7 kV class. -17-(19) 1378475 In a structure in which the interval between the two is widened, it is difficult to make the arrester The voltage sharing of the element 61a becomes uniform. In this embodiment, the front end portion of the arrester element laminate 61 (the length of 1/3 of the length of 61) and the intermediate portion (the length of the 1/3 of the arrester element laminate 61) are located. In the machine casing 1, the rear end portion of the arrester element laminate 61 (the length of 1/3 of the arrester element laminate 61) is located outside the machine casing 1 'the high-pressure die-cast body 4 and the grounding body The interval between the machine casings 1 is appropriately adjusted to φ, and the electric field in the intermediate portion of the arrester element laminate 61 can be appropriately controlled, and the voltage sharing of the arrester element 61a can be uniformized as described above. The lightning arrester of the first structure can be attached to the bushing 2 of the opening 1a of the machine casing 1 in an airtight manner, and the arrester element laminate 61 can be detachably attached from the outside of the machine casing i. It is not necessary to install all the cutting devices of the conventional gas insulated barrel type arrester to simplify the structure of the machine. 2: When performing the withstand voltage test, # It is not necessary to recover the insulating gas in the machine casing 1 and 塡Filling the homework, number 3: by making A portion (low-pressure side) of the lightning device element laminate 61 is led to the outside of the machine casing, and the reduction of the machine can be achieved. Fourth: by the arrester molded body 6 including the arrester element laminate 61 The periphery of the upper end portion side (high-voltage side) of the arrester element laminate 61 in the bushing 2 is covered by the shield main body 41 embedded in the upper cylindrical portion 51, and the voltage sharing of the arrester element can be uniformized. It can also be applied to the high voltage line of the 66/77kV class. '5: The rubber molding system is pressed toward the front end of the bushing' to ensure the insertion of the bushing -24 - (20) 1378475 into the inner surface of the hole and the rubber The surface pressure between the outer faces of the molded body can prevent insulation damage at the interface. Chapter 6: A rear end side spring 66 is disposed at the rear end portion of the arrester molded body 6, by paying the rear end side spring 66 The arrester molded body 6 can be pressed toward the front end portion of the bushing 2 by a spring force, and the seventh: the outer surface of the rubber molded body 67 can be fitted to the inner surface of the bush 2, and the shaft can be rotated. The pressing force in the direction is effective as the surface pressure, that is, by the conical portion 67b of the rubber molded body 67' The interface between the inner peripheral surfaces of the insertion hole 53c is biased to a specific surface pressure to improve the insulation performance at the interface between the two, and the eighth: the spring force of the rear end side spring 66 and the front end side spring The synergistic effect of the spring force of 63 can provide a specific surface pressure between the arrester element 61a and the connecting conductor 62, between the arrester element 6 1 a, between the arrester element 6 1 a and the pressing portion 65b, and the ninth: In the case of withstand voltage test or the like, the arrester cover body 6 is removed by the sealing cover F, and the arrester molded body 6 is pushed out of the rear end side of the bushing 2 by the spring force of the front end side spring 63, so that the arrester molded body 6 can be easily performed. Removed. [Embodiment 2] Fig. 4 is a cross-sectional view showing a portion of a lightning arrester in a second embodiment of the present invention. In the drawings, the same portions as those in the first embodiment are denoted by the same reference numerals, and the detailed description is omitted. In this embodiment, the bushing 2 is formed of an insulating material such as epoxy resin, and the cut-off portion Z is formed at the rear end portion of the bush 2 which is led out of the machine casing 1. Specifically, the portion from the end surface of the rear end portion of the cylindrical portion 52 of the lower portion of the insulating cylindrical member to the outer wall of the machine casing 1 - 25 - (22) 1378475 [Example 3] 5 (a) Fig. 5 is a partial cross-sectional view of the arrester in the third embodiment of the present invention, and Fig. 5(b) is a plan view showing the seal cap in the embodiment. In the drawings, the same portions as those in the first embodiment are denoted by the same reference numerals, and the detailed description is omitted. In the fifth embodiment, the lightning arrester molded body 6 includes a lightning protection-φ device element laminate 61 formed by laminating a plurality of arrester elements 61a mainly composed of oxidized zinc, and is disposed on The connection conductor 62 on the front end side (high voltage side) of the arrester element laminate 61 and the columnar press holder 64' disposed on the rear end side (low pressure side) of the arrester element laminate 61 are covered and covered. The insulating conductor molded body 67d made of ruthenium rubber or the like is integrally molded on the outer circumference of the arrester element laminated body 6 by the connecting conductor 62 and the pressing holder 64, and the insulating molded body 67d and the insertion space of the bushing 2 are provided. There is a gas layer G. In order to integrate the arrester element laminate 61, the # connection conductor 62, and the press holder 64, the insulating molded body 67d has a sufficient thickness, and the thickness is made thin to the extent that the arrester module is used. The cast body 6 is housed in the inside of the bushing 2, and a gas layer G is formed between the arrester molded body 6 and the insertion hole of the bushing 2 (the upper insertion hole 51a, the push-pull insertion hole 53a, and the lower insertion hole 52a). Further, by providing such an insulating molded body 67d on the outer periphery of the arrester element laminate 61, the electric field of the outer surface of the arrester element laminate 61 can be alleviated. Here, the insulating molded body 67d may be formed of a molded body of rubber or plastic resin such as epoxy resin instead of the molded body of the rubber. -27-(25) 1378475 [Embodiment 4] Fig. 7 is a view showing the insulation of the arrester molded body 6 detachably and detachably mounted in the bushing when the voltage withstand test of the machine is performed. A partial section of the plug. In the drawings, the same reference numerals are given to the same portions as the first and second drawings, and the detailed description is omitted. In Fig. 7, the insulating plug 20 of the present invention is provided with an insulating plug body 21 attached to the push-pull insertion hole 53a of the lining 'φ sleeve 2, and above the insulating plug body 21, and the upper circle The tubular portion 51 is concentrically attached to the cylindrical connecting member 22 in the upper insertion hole 51a of the bushing 2, and is disposed below the insulating plug body 21, and is attached to the bushing concentrically with the lower cylindrical portion 52. The lower portion of the lower insertion hole 5 2a is inserted into the cylindrical pressing member 23 at the upper end. Here, the contact member 22 is formed of a metal such as an aluminum alloy, and has an outer diameter which is smaller than the diameter of the upper insertion hole of the bushing, and the length in the axial direction is set to be the same as that of the high-pressure molded body 4. The distance between the top inner wall 41b and the upper wall 27b of the high-voltage side electrode 27, which will be described later, is equal. Specifically, the length of the contact member 22 in the axial direction is such that the front end portion of the contact member 22 and the top inner wall of the high-pressure molded body 4 are in a state where the insulating plug 20 is attached to the normal position in the bush 2 41b is in electrical contact with the length of the rear end portion in electrical contact with the upper wall 27b of the high voltage side electrode 27. Further, the pressing member 23 is formed of a metal such as an aluminum alloy, and a thick plate portion 23a is provided along a shaft direction in a part of the cylindrical portion. Further, a plurality of screw insertion holes 23c which are arranged at equal intervals in the circumferential direction are provided in the closing portion 23b of the pressing member 23, and the rear end surface of the thick plate portion 23a is provided with a -30-(26) 1378475 screw. The hole 23d❶ is provided with a cylindrical portion 24 having an outer diameter slightly larger than the diameter of the lower insertion hole 52a of the bushing 2, and a front end portion connected to the cylindrical portion 24, and is disposed in the lining The conical portion 25 of the sleeve 2 with the push-pull insertion hole 53a and the rear end portion of the cylindrical portion 24, and the hemispherical low-pressure side electrode 26, _ and the conical portion of the spherical convex portion 26a toward the distal end portion are embedded in the conical portion The front end portion of the portion 25 has a spherical convex portion 27a and a hemispherical high-voltage side electrode 27 facing the 'φ low-voltage side electrode 26. Here, the outer surface of the conical portion 25 has a push-out outer surface 25a that is fitted to the push-pull inner surface 53b of the bushing 2, and the diameter of the low-pressure side electrode 26 is set to be slightly smaller than the diameter of the cylindrical portion 24. Further, the lower end surface is buried in the same plane as the lower end surface of the columnar portion 24, and the lower end surface of the low-pressure side electrode 26 is provided with a plurality of spring receiving holes 26b disposed at equal intervals in the circumferential direction. Multiple screw holes 2 6 c. The columnar portion 24 and the conical portion 25 are formed of a material such as an ethylene propylene rubber, and are molded integrally with the low pressure side electrode 26 and the high pressure side electrode 27. Next, a method of detachably mounting the insulating plug 20 thus constructed in the bushing 2 will be described. First, the screw V 2 shown in Fig. 1 is removed, the sealing cover F is removed from the lower cylindrical portion 52 of the bushing 2, and the arrester molded body 6 is removed from the bushing 2, and then 'as shown in Fig. 7 In the same manner, the spring 28 is disposed in the spring receiving hole 26b of the low-voltage side electrode 26 so that the lower half thereof protrudes from the spring receiving hole 26b-31 - (28) 1378475 withstand voltage test, etc., and the arrester molded body 6 The insulating plug 20 is exchangeably inserted into the insertion hole of the bushing 2, and the insulation in the insertion hole of the bushing 2 in the state in which the arrester molded body 6 is removed can be ensured. Further, by placing the insulating plug 20 on the inner side of the rear end side end portion of the high-voltage molded body 4 where the electric field is concentrated, the control of the electric field in the state in which the insulating plug 20 is mounted can be effectively performed, and further, only By sealing the inner side of the end portion of the rear end side of the high-pressure molded body 4, insulation in the insertion hole of the bush 2 can be ensured, and the size of the φ insulating plug 20 can be reduced. [Embodiment 5] Fig. 9 is a cross-sectional view showing a portion of a lightning arrester in a first embodiment of the present invention. In the drawings, the same components as those in the drawings are denoted by the same reference numerals, and the detailed description is omitted. In Fig. 9, in this embodiment, a conductive coating layer 75 is provided on the outer peripheral surface of the front end portion of the bushing 7, as indicated by a broken line. Here, the bushing 7 of the fifth embodiment is provided with an intermediate cylindrical portion 7 1 ' provided with an annular recessed portion 71a in the vicinity of the outer periphery of the upper surface thereof, and concentric with the intermediate cylindrical portion 71 The upper end portion of the intermediate cylindrical portion 71 is connected to the upper end portion of the intermediate cylindrical portion 71, and has a smaller diameter than the outer diameter of the intermediate cylindrical portion 71, and has a tapered end portion 7 2a at the distal end portion, and the upper end portion is closed with the upper cylindrical portion 72. And a lower cylindrical portion 73 that is concentrically connected to the intermediate cylindrical portion 71 in the vicinity of the outer peripheral edge of the lower surface of the intermediate cylindrical portion 71, and has a smaller diameter than the outer diameter of the intermediate cylindrical portion 71, and its own The front end portion protrudes from the lock portion 72b and is buried in the main circuit connector 74 at the center portion of the lock portion 72b of the upper cylindrical portion 72. -33- (30) 1378475 [Embodiment 6] Fig. 11 is a cross-sectional view showing a portion of a lightning arrester in a sixth embodiment of the present invention. In the drawings, the same components as those in the drawings are denoted by the same reference numerals, and the detailed description is omitted. In the first embodiment, in this embodiment, the high-pressure shield 10 to which another body is fixed is placed on the front end portion of the bushing 8. Here, the bushing 8 of the sixth embodiment includes a 'φ inter-cylinder portion 8 1 ' between the tip end and a concentric shape connected to the intermediate cylindrical portion 81 at the upper end of the intermediate cylindrical portion 81. The portion is smaller than the outer diameter of the intermediate cylindrical portion 81, and the upper cylindrical portion 82 and the intermediate cylindrical portion 81 are connected concentrically to the lower end portion of the intermediate cylindrical portion 81 and to the intermediate cylindrical portion 81. The lower end portion has an outer diameter slightly smaller than the lower portion cylindrical portion 83, and an annular mounting flange 83a is provided on the outer periphery of the lower end portion of the lower cylindrical portion 83. The high-pressure shield 10 has a cylindrical shape with the upper end closed. The metal member 1 1 and the main circuit connector 13 of the central portion of the metal member 11 are vertically erected from the latch portion 2 . As shown in the figure, the high-voltage shield 10 of such a structure has the main circuit connector 13 disposed above the upper cylindrical portion 82, and the side wall portion 14 of the metal member 11 is located at the side wall portion 82a of the upper cylindrical portion 82. The periphery of the upper cylindrical portion 82 is fixed to the front end portion of the upper cylindrical portion 82 so as to be placed concentrically with the upper cylindrical portion 82. Fig. 12 is a view showing the potential distribution of the arrester in the sixth embodiment. According to the figure, in this embodiment, the same as the arrester in the first embodiment, the front end portion of the arrester element laminate 61 is formed by a cylindrical shape constituting the high-voltage shield -35-(31) 1378475 Since the metal member 11 is shielded, the electric field is not concentrated on the front end portion. The rear end portion of the arrester element laminate 61 is disposed outside the machine casing 1 as the grounding body, and the electric field is not concentrated on the rear portion. The intermediate portion of the end portion and further the arrester element laminate 6] is controlled by the adjustment of the interval between the cylindrical metal member 11 and the machine casing 1 as the grounding body, so that the electric field is also known. It is not concentrated in the intermediate portion 〇φ. As described above, in the lightning arrester of the sixth embodiment, the voltage sharing of the arrester element 61a as a whole can be made uniform. Further, the arrester in this embodiment can be applied to an oil insulated, gas insulated or air insulated type electric appliance. [Embodiment 7] Figure 13 is a cross-sectional view showing a portion of a lightning arrester in a seventh embodiment of the present invention. In the drawings, the same reference numerals are given to the parts that are common to the first embodiment and the drawings, and the detailed description is omitted. In Fig. 13, in this embodiment, the high-voltage shield 1 shown in Fig. 9 is placed and fixed on the front end portion of the bushing 9. In addition, the periphery of the high-voltage shield 10 is insulated as follows. Covered by the barrier 9115. Here, the bushing 9 of the seventh embodiment is provided with an upper cylindrical portion 91 having an annular recessed portion 91a and a concentric shape connected to the upper cylindrical portion 91 in the vicinity of the outer periphery thereof. a lower end portion of the upper cylindrical portion 91 and a lower diameter cylindrical portion 92 than the outer diameter of the upper cylindrical portion 911, and then a rolling shield having the same structure as that of the eleventh figure, -36- (32) 1378475 The side wall portion 14 is disposed concentrically with the upper cylindrical portion 9 1 so as to be positioned in the recess portion 91a of the upper cylindrical portion 91. Further, in the bushing 9 of this embodiment, the outer diameter of the upper cylindrical portion 91 is larger than the opening portion la of the machine casing 1, and the lower surface of the outer peripheral edge of the upper cylindrical portion 91 is airtightly placed. , fixed to the inner surface of the machine casing. Fig. 14 is a view showing the potential distribution of the arrester in the seventh embodiment. According to the figure, in the present embodiment, also in the same manner as the arrester phase *φ in the first embodiment, the front end portion of the arrester element laminate 61 is formed by a cylindrical metal member U as a high-pressure shield. The electric field is not concentrated on the front end portion, and the rear end portion of the arrester element laminate 61 is disposed outside the machine casing 1 as a grounding body, and the electric field is not concentrated on the rear end portion, and further The intermediate portion of the arrester element laminate 61 is controlled by the interval between the cylindrical metal member 11 and the machine casing as the grounding body, and the electric field is controlled to know that the electric field is not concentrated on the intermediate portion. As described above, in the arrester in the seventh embodiment, as a whole, # can make the voltage sharing of the arrester element laminate 61 uniform. Further, in the lightning arrester of the embodiment, the side wall portion 14 of the high-pressure shield 10 is disposed in the recessed portion 91a of the upper cylindrical portion 91, and is provided with insulation around the cylindrical metal member 1 Since the barrier member 91b is formed, the insulation distance between the phases can be shortened or the insulation distance from the machine casing 1 can be shortened, and further, the size of the machine can be reduced. Further, the lightning arrester in this embodiment can be applied to an electric appliance in the form of oil insulation, gas insulation or air insulation. [Embodiment 8] -37- (34) 1378475 Voltage sharing uniformity of the arrester element 61a In addition, in the eighth embodiment, the case where the high-pressure shield 20 is embedded in the rubber molded body 67 will be described. However, the rolling shield 20 may be disposed on the outer circumference of the rubber molded body 67. [Industrial Applicability] The present invention can be modified or modified as described below within the scope of the patent application. First, in the foregoing embodiment, the case where the bushing is provided at the bottom of the machine casing 1 is described. However, the bushing may be disposed on the side wall of the machine casing 1. Second: In the foregoing embodiment, although the case where the 66/77 kV high voltage line is applied to the lightning arrester of the present invention is described, the present invention can also be used for a line lower than 6 6 kV or a high voltage line exceeding 77 kV. lightning arrester. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partial cross-sectional view showing a lightning arrester in a first embodiment of the present invention. Fig. 2 is a partial cross-sectional view showing the arrester molded body of the first embodiment of the present invention. Fig. 3 is a diagram showing the equipotential distribution of the arrester in the third embodiment of the present invention. Fig. 4 is a partial cross-sectional view of the arrester in the second embodiment of the present invention - 39 - (35) 1378475. Fig. 5 is a partial cross-sectional view showing the arrester in the third embodiment of the present invention. Fig. 6 is a diagram showing the equipotential distribution of the arrester in the third embodiment of the present invention. Fig. 7 is a partial cross-sectional view showing the insulating plug in the fourth embodiment of the present invention. Fig. 8 is an isobaric distribution diagram of the insulating plug in the fourth embodiment of the present invention. Figure 9 is a cross-sectional view showing a portion of the arrester in the fifth embodiment of the present invention. The figure is an equipotential distribution diagram of the arrester in the fifth embodiment of the present invention. Fig. 1 is a cross-sectional view showing a portion of the arrester in the sixth embodiment of the present invention. #图图图 is an equipotential distribution diagram of the arrester in the sixth embodiment of the present invention. Figure 13 is a cross-sectional view showing the portion of the arrester in the seventh embodiment of the present invention. Figure 14 is a diagram showing the equipotential distribution of the arrester in the seventh embodiment of the present invention. Figure 15 is a cross-sectional view showing a portion of the arrester in the eighth embodiment of the present invention. Figure 16 is a partial cross-sectional view of a conventional arrester. -40- (36) (36)1378475 Figure 17 is a partial cross-sectional view of a conventional arrester. Figure I8 is a partial cross-sectional view of a conventional insulating plug. [Description of main component symbols] 1 : Machine housing ] a : Opening 2 : Bushing 3 : Bushing body 4 : High-voltage shield 6 : Lightning arrester molded body 1 1 : Cylindrical metal fitting 20 : Insulating plug 2 1 : Insulation plug body 2 2 : Contact member 2 3 : Pressing member 4 1 : Shielding body 4 1 a : Side wall portion 42 : Connecting conductor insertion portion. 43: Main circuit connector 5 1 : Upper cylindrical portion 5 1 a : Upper insertion hole 5 1 b : Locking portion 5 2 : Lower cylindrical portion 5 2 a : Lower insertion hole - 41 - (37) 1378475 52b : Installation Flange 5 3 : intermediate cylindrical portion 5 3 a : push-pull insertion hole 53b : push-out inner surface 61 : arrester element laminate 6 1 a : arrester element 62 : connection conductor φ 6 3 : front end side spring 65b: Annular member 66: rear end side spring 6 7 a : small diameter portion 67b : conical portion 67c : push outer surface 6 7 d : large diameter portion 6 7 : rubber molded body (insulated molded body) • 67d : insulation Molded body 7 5 : Conductive coating layer 9 1 b : Insulating barrier F : Sealing cap G : Gas layer N : Screw hole P1 : 0 ring V 1 : Screw V 2 : Screw - 42-