201223046 六、發明說明： - 【發明所屬之技術領域】 ? 本發明係關於一種襯套部（bushing)，其係例如對於以 可拉出的方式配置於配電盤之框體内《真空斷路器等開閉 機器，以可接離自如之方式設置在其背面側而作為主= 斷路部者。 【先前技術】 連接有真空斷路器等裳置之主電路的電流通電部係必 須依規格將額定電流通電時之溫度上昇值設定在預定值以 下。並且，由安全性（保護等級）之觀點來看，為了 往危險部位接近之人的保護、或對固體異物不會侵入= 置内之裝置的保護，而以箱體或隔壁等覆蓋幾乎^個裝 置。因此，在主電路之通電部中，需要有進: 昇值之條件的構造上之考量。 /足脱度上 就考量主電路斷路部之溫度上昇的習知構造而言，例如 如第7圖所示揭示有以下之技化在使中心導體2Q貫插之 絕緣層21的一侧，同軸地突設作成方形之小徑的筒部 及大徑之筒部21b，其中，在筒部21a之上下，對應於與8 接觸件22和中心導體20之嵌合部相對向之位置設置通氣 口 23在外側之筒部2ib ’於前方之上下設置通氣口 24， 利用冷卻氣體之對流提升冷卻效果，該冷卻氣體係藉由從 接觸件22和中心導體20之接觸部分所產生的熱而加熱（例 如參照專利文獻1)。 (先前技術文獻） 4 323009 201223046 (專利文獻） 1〇~322819號公報（第3頁，第201223046 VI. Description of the Invention: - Technical Field of the Invention The present invention relates to a bushing which is, for example, configured to be openable and closable in a frame that can be pulled out in a switchboard. The machine is placed on the back side as a main = disconnection unit in a detachable manner. [Prior Art] The current energizing section to which the main circuit of the vacuum interrupter or the like is connected is required to set the temperature rise value when the rated current is energized to a predetermined value or less according to the specifications. In addition, from the viewpoint of safety (protection level), it is protected by a box or a partition, etc., in order to protect a person who is approaching a dangerous part, or to protect a device that does not intrude into a solid foreign object. Device. Therefore, in the energization portion of the main circuit, it is necessary to have a structural consideration of the condition of the value of the rise. In the conventional structure in which the temperature rise of the main circuit breaking portion is taken into consideration, for example, as shown in Fig. 7, the following technique is disclosed on the side of the insulating layer 21 through which the center conductor 2Q is inserted, coaxially The ground protrusion is formed as a cylindrical small-diameter cylindrical portion and a large-diameter cylindrical portion 21b in which a vent hole is provided above and below the cylindrical portion 21a so as to correspond to a fitting portion of the 8-contact member 22 and the center conductor 20. 23, the outer tube portion 2ib' is provided with a vent 24 above and below the front side, and the cooling effect is enhanced by the convection of the cooling gas, which is heated by the heat generated from the contact portion of the contact member 22 and the center conductor 20. For example, refer to Patent Document 1). (Previous Technical Literature) 4 323009 201223046 (Patent Document) Bulletin No. 1~322819 (Page 3,
(專利文獻1)日本特開平 2圖） 【發明内容】 (發明所欲解決之課題） 在專利文獻1所述知的主電路斷路部（以下稱為 中，由於對突設於•層21之各筒部之侧面在垂直 方向設置有通氣口，因此彻 s 01 . n 例如在藉由注模加工來製作絕緣 層21時，會有模具之構造 、、變传複雑，且加工耗費時間與費 用之問題。 連技t在專利文獻1所述之形狀中，由於形成為僅在 =有斷路ϋ等之⑽件的連接部側進行空氣之流通的構 因此有，、進彳了該連接部侧之冷卻，而無法抑制相反側 即連接有母線等主電路導體之側）的溫度上昇之問題。 〜本發月係為了解★切問題*研創者，其目的在於獲 件一種能以簡單之構成⑽通電時之溫度上昇且冷卻效果 佳之襯套。 (解決課題之手段） 本發明之襯套係貫設在載置有開閉機器之固定框之 背面侧的壁面，且具有絕緣筒及貫插在該絶緣筒之中心的 中心導體，在中心導體之一方端部連接有開閉機器之主電 路端子，在中心導體之另一方端部連接有主電路導體，其 中’絕緣筒係具有筒部、位於筒部之一端側且固定在壁面 之凸緣部、及位在另一端側之開口端附近且安裝有中心導 5 323009 201223046 - 體之安裝部，中心導體係具有從安裝部朝筒部之内側突出 *. 且連接有主電路端子之端子連接部、及安裝在安裝部且在 • 外侧端面連接有主電路導體之主電路連接部，且在主電路 連接部之安裝部側設置有朝與中心導體之轴線正交之方向 貫通的通氣口 ^ (發明之效果） 依據本發明之襯套，由於襯套之絕緣筒係具有筒部、 位於筒部之一端側且固定在壁面之凸緣部、及位在另一端 側之開口端附近且安裝有中心導體之安裝部，中心導體係 具有比安裝部更朝筒部之内侧突出且連接有主電路端子之 端子連接部、及安裝在安裝部且在外侧端面連接有主電路 導體之主電路連接部，且在主電路連接部之安裝部側設置 有朝與中心導體之軸線正交之方向貫通的通氣口，因此能 以簡單之構成直接冷卻通電路，因而可抑制通電部之溫度 上昇且有效率地冷卻襯套部。 【實施方式】 (實施形態1) 以下，依據圖式說明本發明之實施形態丨之襯套。 外有圖係顯示在收容有真空斷路器之蚊框的背面配 圖又=，且在襯套連接有真空斷路器之狀態的側面剖視 二之側而圖係顯7^第1圖之襯套的斜視圖。第3圖係第2 圖之側面剖視圖。(Patent Document 1) Japanese Patent Application Laid-Open No. 2-------------------------------------------------------------------------------------------------------------- The side surface of each tubular portion is provided with a vent hole in the vertical direction. Therefore, for example, when the insulating layer 21 is formed by injection molding, the structure of the mold is changed, and the mold is transferred and recovered, and the processing takes time and expense. In the shape described in the patent document 1, the configuration is such that the air is circulated only on the side of the connection portion of the (10) member having a disconnection or the like, and the connection portion side is advanced. The cooling is performed, and the problem of temperature rise on the opposite side, that is, the side on which the main circuit conductor such as the bus bar is connected, cannot be suppressed. ~ This month is to understand the ★ cut problem * researcher, the purpose is to obtain a simple configuration (10) when the temperature rises when the power is on and the cooling effect is good. (Means for Solving the Problem) The bushing of the present invention is disposed on a wall surface on the back side of the fixing frame on which the opening and closing device is placed, and has an insulating cylinder and a center conductor that is inserted into the center of the insulating cylinder, and is centered on the center conductor. a main circuit terminal of the opening and closing device is connected to one end, and a main circuit conductor is connected to the other end of the center conductor. The insulating cylinder has a cylindrical portion, a flange portion which is located at one end side of the tubular portion and is fixed to the wall surface, And a central guide 5 323009 201223046 - a mounting portion of the body, the center guide system having a terminal connection portion that protrudes from the mounting portion toward the inner side of the tubular portion and is connected with the main circuit terminal, And a main circuit connection portion that is attached to the mounting portion and has a main circuit conductor connected to the outer end surface, and a vent hole that penetrates in a direction orthogonal to the axis of the center conductor is provided on the mounting portion side of the main circuit connection portion ( Advantageous Effects of Invention According to the bush of the present invention, the insulating cylinder of the bushing has a cylindrical portion, a flange portion which is located at one end side of the tubular portion and is fixed to the wall surface, and is located at the other end side. A mounting portion of the center conductor is mounted near the mouth end, and the center guiding system has a terminal connecting portion that protrudes toward the inner side of the tubular portion and is connected to the main circuit terminal, and is mounted on the mounting portion and has a main circuit connected to the outer end surface. The main circuit connecting portion of the conductor is provided with a vent hole penetrating in a direction orthogonal to the axis of the center conductor on the mounting portion side of the main circuit connecting portion. Therefore, the through circuit can be directly cooled by a simple configuration, thereby suppressing the energizing portion The temperature rises and the liner portion is efficiently cooled. [Embodiment] (Embodiment 1) Hereinafter, a bushing according to an embodiment of the present invention will be described with reference to the drawings. The external diagram shows the side of the mosquito frame in which the vacuum circuit breaker is housed, and the side of the side view of the bushing is connected to the side of the side view. Set of oblique views. Figure 3 is a side cross-sectional view of Figure 2.
323009 6 201223046 接部（斷路部）的襯套加以說明。 構成配電盤之框體（未圖示）的内部係劃分成：收容有 斷路器之斷路器室、收容有母線之母線室、及收容有纜線 之纜線室等。如第1圖所示，配置在構成斷路器室之固定 框1内的真空斷路器2係具備：台車3，具有車輪且可朝 前後方向移動；絕緣框架4，固定在台車3上；真空閥5， 収容在絕緣框架4之内部；及驅動機構（未圖示），連結在 真空閥5之可動側接點（未圖示），且使可動侧接點接離在 固定側接點（未圖示）。再者，從固定侧接點導出上部主電 路端子6,從可動侧接點導出下部主電路端子7,且分別固 定在絕緣框架4。在各主電路端子6、7之前端部，設置有 例如後述之手指形之接觸件8。 在位於真空斷路器2之背面側的固定框1之壁面，貫 設有上部襯套10及下部襯套11，而使與上部主電路端子6 及下部主電路端子7相對向。 在第1圖中，顯示連接有真空斷路器2之上下之主電 路端子6、7及上下之襯套10、11的狀態，若為將真空斷 路器2連同台車3拉出至前面側，則由上述連接狀態變成 為斷路狀態，且進一步形成可將真空斷路器2從框體前面 取出至配電盤外。 第2圖係顯示第1圖之襯套構造的斜視圖，第3圖係 第2圖之襯套的側面剖視圖。上部襯套10及下部襯套11 基本上為相同形狀，因此以下係以上部襯套10為例加以說 明。 7 323009 201223046 在第2圖、第 氧樹脂等絕緣材料^中’上部襯套1G係具備由例如環 12之中心的中心導體1 成之絕緣冑12、及貫插在該絕緣筒323009 6 201223046 The bushing of the joint (breaking section) is explained. The inside of the casing (not shown) constituting the switchboard is divided into a breaker chamber in which a circuit breaker is housed, a busbar chamber in which a busbar is housed, and a cable compartment in which a cable is housed. As shown in Fig. 1, the vacuum circuit breaker 2 disposed in the fixed frame 1 constituting the circuit breaker chamber includes a trolley 3 having a wheel and movable in the front-rear direction, and an insulating frame 4 fixed to the trolley 3; 5, is housed inside the insulating frame 4; and a driving mechanism (not shown) is connected to the movable side contact (not shown) of the vacuum valve 5, and the movable side contact is disconnected from the fixed side contact (not shown) Graphic). Further, the upper main circuit terminal 6 is led out from the fixed side contact, and the lower main circuit terminal 7 is led out from the movable side contact, and is fixed to the insulating frame 4, respectively. At the end portions of the main circuit terminals 6, 7, a contact member 8 of a finger shape, which will be described later, is provided. The upper bushing 10 and the lower bushing 11 are disposed on the wall surface of the fixed frame 1 on the back side of the vacuum circuit breaker 2 so as to face the upper main circuit terminal 6 and the lower main circuit terminal 7. In the first diagram, the state in which the main circuit terminals 6, 7 and the upper and lower bushings 10, 11 of the vacuum circuit breaker 2 are connected is connected, and if the vacuum circuit breaker 2 is pulled out to the front side with the trolley 3, From the above-described connection state to the open state, and further formed, the vacuum circuit breaker 2 can be taken out from the front of the casing to the outside of the switchboard. Fig. 2 is a perspective view showing the bushing structure of Fig. 1, and Fig. 3 is a side cross-sectional view of the bushing of Fig. 2. Since the upper bushing 10 and the lower bushing 11 have substantially the same shape, the upper bushing 10 will be described below as an example. 7 323 009 201223046 In the insulating material such as the second embodiment of the oxygen resin, the upper bushing 1G is provided with an insulating bush 12 made of, for example, the center conductor 1 at the center of the ring 12, and is inserted in the insulating cylinder.
絕緣筒12係且右且+ A 1 〇a ^ Pa 、有長方體狀之筒部12a、設置在筒部 12h ^端側且安裝在固定框1之矩形的凸緣部 、筒邛12a之軸線垂直的方向設置 口端附近㈣侧且安料中心導體13之絲部心。之開 中心導體13係具有從安裳部心朝筒部…之内側 =且連射真”路器2之上部主電路端子6之圓柱狀 胜端子連接部13a、及安|在安裝部12c且在外侧端面（安 、面之相反側）連接有未圖示之母線紐料主電路導體 之主電路連接部13b。（從安裝至安裝部…之安裝面開 始，將筒部内侧設為端子連接部13a，將開口部側設為主 電路連接部13b。） 1端子連接部1如與主電路連接部13b亦可以同一構件 製作，且亦可藉由硬銲等來接合個別地製作者。 如第3圖所示，在真空斷路器2側之上部主電路端子 6的前端側，設置有手指形之接觸件8，中心導體13之端 子連接部13a係與該接觸件8滑動接觸而成電性連接。 接觸件8係在真空斷路器2之上部主電路端子6及下 部主電路端子7之前端部外周，以環狀組裝有複數個接觸 件片8a，且耩由s免置在接觸件片外周側之環狀彈簧gb朝 内徑方向彈壓。藉由該彈簧力，施加接觸荷重以使接觸件 片8a之内周側的一方凸部接觸於中心導體13之端子連接 323009 8 201223046 部13a的外周。 本案之特徵為在中心導體13之主電路連接部13b設 置通氣口，且在端子連接部13a設置連通口之點，因此接 著針對其詳細内容加以說明。 通氣口係開通在與中心導體13之軸線正交的方向（亦 即與安裝部12c之安裝面平行的方向），如第2圖、第3 圖所示，朝垂直方向貫通之通氣口 14a、及朝水平方向貫 通之通氣口 14b係形成為十字形，且於中央部相連接。在 以不同構件製作端子連接部13a及主電路連接部13b之情 形時，通氣口 14a、14b係只要在主電路連接部13b之安裝 面側設置剖面：？字形之溝槽即可。 再者，如第3圖的側面剖視圖所示，使端子連接部13a 之中心朝軸線方向，且形成有從通氣口 14a、14b之中央部 連通至筒部12a之内部側的連通口 14c。 接著，針對如上構成之襯套的通氣口 14a、14b及連 通口 14c之作用加以說明。 真空斷路器及主電路導體部之溫度會因通電而產生 之焦耳熱的發熱而上昇。然而，真空斷路器内部及主電路 導體部係為了使人無法接近且防止固體異物侵入，必須採 取保護對策，因此幾乎整體係由某一形式所覆蓋。因此， 散熱效果低，而必須有要以符合溫度上昇值之條件的考量。 因此，本發明係如上所述，在襯套10之中心導體13 設置通氣口 14a、14b及連通口 14c者。 襯套部10雖會因流通於襯套10之中心導體13的電 9 323009 201223046 . 流而溫度上昇，但從通氣口 14a、14b進行空氣之吸氣與排 • 氣’主電路連接部13b被冷卻，且端子連接部13a側亦會 • 因熱傳導而也被冷卻。 再者’藉由設置連通口 14c，如第4圖所示，連通口 14c會與通氣口 14a、14b連接，且形成有從固定框1之背 面側通往真空斷路器2之收容侧的空氣流路，因此空氣例 如會如箭頭所示流動，而可將端子連接部與各主電路端子 之接觸件的連接部予以直接冷卻。 此外’可經由上下之襯套10、11對斷路器室内部之 空氣進行吸氣/排氣，且可獲得更高之冷卻效果。 再者’在屬於通電部之中心導體13本身設置通氣口 及連通口 ’該等通氣口及連通口皆朝人的手指等難以接近 之方向開通’因此符合通電部之安全性（保護等級），同時 也可符合對空氣進行吸氣/排氣用之通氣口與連通口之完 全性（保護等級）。 此外’在上述說明中，中心導體13之主電路連接部 13b的形狀雖在轴線方向觀看形成為矩形，但並不限定於 此’亦可為圓形。此時，筒部12a亦可形成為圓筒。 再者’通氣口雖在水平方向及垂直方向設置二部位 (Ua、14b)，但亦可設置任一部位。 此外’雖在端子連接部l3a之中心設置連通口 14c ’ 但在通電電容小之情形時，亦可不設置該連通口 14c。 如上所述，依據實施形態1之襯套，係貫設在載置有 開閉機器之固定框之背面側的壁面，且具有絕緣筒及貫插 323009 10 201223046 在該絶緣筒之中心的十心導體，在中心導體之一方端部連 接有開閉機器之主電路端子，在中心導體之另一方端部連 接有主電路導體的襯套中，絕緣筒係具有筒部 、位於筒部 之一端側且固定在壁面之凸緣部、及位在另一端側之開口 端附近且安裝有中心導體之安裝部，中心導體係具有從安 裝部朝筒部之内側突出且連接有主電路端子之端子連接 部、及女裝在安裝部且在外側端面連接有主電路導體之主 電路連接部，且在主電路連接部之安裝部側設置有朝與中 心導體之軸線正父之方向貫通的通氣口，因此能以簡單之 構成對通電部進行直接冷卻，且可抑制通電部之溫度上昇 且效率佳地對襯套進行冷卻。 此外，由於通氣口係在水平方向及垂直方向形成為十 字狀，因此可在襯套之中心導體的内部對來自外部之空氣 有效地進行吸氣/排氣，因此可獲得高度之冷卻效果。 再者，在中心導體之端子連接部的中心設置有從通氣 口連通至筒部之内部侧的連通口，因此可經由襯套對開閉 機器侧之空氣進彳于吸氣/排氣’特別是可對溫度上昇變高之 端子接觸部有效地進行冷卻’因而可抑制通電部之溫度上 昇，且獲得高度之冷卻效果。 (實施形態2) 第5圖係本發明之實施形態2之襯套的斜視圖。第6 圖係第5圖之襯套的側面剖視圖。與包含配置在固定框1 内之真空斷路器2的開閉機器侧之連接構造係與實施形態 1之第1圖相等’因此省略圖示及說明，以相異點為中心 323009 11 201223046 加以說明。 ，構成配電盤之電氣機n的連接導⑽必須充分地承 受額定電流、額定短時間耐電流及額定峰值耐電流。而且， 連接導體之絕緣支持部係必須成為充分地承受短路電流通 電時之電磁力或開閉時之衝擊力等的支持構造。由上述理 由得知，在襯套之中心導體中，亦須充分地確保剖面積， 確實地進行固定，以作成可承受通電或衝擊力之構造。 在實施形態1中說明之第2圖 '第3圖之構造中，雖 可充分地期待冷卻效果，但由上述之觀點來看，亦有需要 更下工夫之情形。 因此’在實施形態2中，如第5圖及第6圖所示，設 置在上部襯套1〇之中心導體13的通氣口係例如僅作為朝 垂直方向設置在主電路連接部l3b之安裝面的通氣口 14a， 另一方面’係在絕緣筒12之安裝部12c之比主電路連接部 13b之外周更外側的左右上下4部位，設置朝與中心導體 13之軸線平行的方向貫通之通氣開缝15。通氣開縫15係 藉由設為使人體之一部分（手指等）進不去之大小（寬度）， 而可符合安全性（保護等級）之條件。 接著’針對該構成之作用進行說明。 藉由將設置在襯套之中心導體13的通氣口僅最小限 度地例如設有通氣口 14a，即可在幾乎不會犠牲電流電容 與支持部（端子連接部13a與主電路連接部13b之接合部） 之強度的情況下，進行中心導體13之冷卻，並且藉由貫通 於絕緣筒12之安裝部12c的通氣開縫15，即能與實施形 12 323009 201223046 態1之第4圖中說明者同樣地，形成通過襯套10(及11) 之内部且往來於真空斷路器側與主電路導體側之空氣的流 路，藉此亦可進行真空斷路器2之絕緣框架4内部之空氣 的吸氣/排氣，且可獲得更高之冷卻效果。 並且，設置在絕緣筒12之安裝部12c的通氣開縫15 係形成在絕緣筒12之軸方向（成形加工之衝壓方向），因此 無須在成形時進行特別之追加加工，而可簡單且廉價地進 行力口工。 此外，在以上說明中，通氣開缝15雖係設成在主電 路連接部13b之左右上下設置4個部位，但亦可為例如在 左右或上下之2部位。 並且，設置在中心導體13之通氣口亦可設在水平方 向，若構造上（及電氣上）充裕，亦可與實施形態1同樣地， 設置在垂直方向及水平方向之2部位，且亦可在端子連接 部13a之中心設置連通口。 如上所述，依據實施形態2之襯套，除了實施形態1 之構成以外，亦在絕緣筒之安裝部設置朝中心導體之軸線 方向貫通之通氣開縫，因此除了實施形態1之效果以外， 亦可進行開閉機器侧之空氣的吸氣/排氣，且可獲得更高之 冷卻效果。 此外，藉由將設置在中心導體之通氣口作成為最小限 度，即可提供一種確保中心導體之電流電容與支持部之強 度且冷卻效果佳之襯套。 再者，由於在絕緣筒之軸方向設置通氣開縫，因此絕 13 323009 201223046 緣筒之製作並不需要特別之追加加工，而能以成形加工容 、 易地進行。 ' 【圖式簡單說明】 第1圖係顯示應用本發明之實施形態1之襯套之真空 斷路器之主電路斷路部的側面剖視圖。 第2圖係用以說明第1圖之襯套構造的斜視圖。 第3圖係第2圖之襯套的侧面剖視圖。 第4圖係說明使用實施形態1之襯套之壁面之空氣流 動的說明圖。 第5圖係本發明之實施形態2之襯套的斜視圖。 第6圖係第5圖之襯套的侧面剖視圖。 第7圖係習知之襯套的側面剖視圖。 【主要元件符號說明】 1 固定框 2 真空斷路器 3 台車 4 絕緣框架 5 真空閥 6 上部主電路端子 7 下部主電路端子 8 接觸件 8a 接觸件片 8b 環狀彈簧 10 上部槪套 11 下部襯套 12 絕緣筒 12a 筒部 12b 凸緣部 12c 安裝部 13 中心導體 13a 端子連接部 13b 主電路連接部 14a、14b 通氣口 14c 連通口 15 通氣開縫 323009 14The insulating cylinder 12 is a right and + A 1 〇a ^ Pa, a tubular portion 12a having a rectangular parallelepiped shape, a rectangular flange portion provided on the end side of the tubular portion 12h and mounted on the fixed frame 1, and an axis perpendicular to the cylinder 12a. The direction of the wire is placed near the (4) side of the mouth end and the wire center of the center conductor 13 of the center. The open center conductor 13 has a cylindrical win terminal connecting portion 13a which is connected to the inner side of the main circuit terminal 6 from the inner side of the armor portion and is connected to the true circuit device 2, and the mounting portion 12c is at the mounting portion 12c. A main circuit connecting portion 13b of a bus bar main circuit conductor (not shown) is connected to the outer end surface (opposite side of the mounting surface). (From the mounting surface to the mounting portion, the inner side of the cylindrical portion is a terminal connecting portion. 13a, the opening side is the main circuit connecting portion 13b.) The one terminal connecting portion 1 may be formed of the same member as the main circuit connecting portion 13b, and may be joined to individual producers by brazing or the like. As shown in Fig. 3, on the front end side of the upper main circuit terminal 6 on the vacuum circuit breaker 2 side, a finger-shaped contact member 8 is provided, and the terminal connecting portion 13a of the center conductor 13 is in sliding contact with the contact member 8 to be electrically The contact member 8 is attached to the outer periphery of the upper main circuit terminal 6 and the lower main circuit terminal 7 at the upper end of the vacuum circuit breaker 2, and a plurality of contact pieces 8a are assembled in a ring shape, and are not placed on the contact piece by s. The annular spring gb on the outer peripheral side is biased toward the inner diameter By the spring force, a contact load is applied so that one convex portion on the inner peripheral side of the contact piece 8a contacts the outer periphery of the terminal connection 32390 8 201223046 portion 13a of the center conductor 13. The present invention is characterized by the main body of the center conductor 13. The circuit connecting portion 13b is provided with a vent hole, and a point is provided at the terminal connecting portion 13a. Therefore, the details will be described later. The vent opening is opened in a direction orthogonal to the axis of the center conductor 13 (that is, with the mounting portion). As shown in Fig. 2 and Fig. 3, the vent hole 14a penetrating in the vertical direction and the vent hole 14b penetrating in the horizontal direction are formed in a cross shape and connected to the center portion. In the case where the terminal connecting portion 13a and the main circuit connecting portion 13b are formed by different members, the vent holes 14a and 14b may be provided with a cross-section of a U-shaped groove on the mounting surface side of the main circuit connecting portion 13b. As shown in the side cross-sectional view of Fig. 3, the center of the terminal connecting portion 13a is oriented in the axial direction, and the communication from the central portion of the vent holes 14a, 14b to the inner side of the tubular portion 12a is formed. Port 14c. Next, the action of the vent ports 14a and 14b and the communication port 14c of the bushing configured as described above will be described. The temperature of the vacuum circuit breaker and the main circuit conductor portion rises due to the heat generated by the Joule heat generated by the energization. The inside of the vacuum circuit breaker and the main circuit conductor are necessary to protect people from inaccessibility and prevent the intrusion of solid foreign matter. Therefore, almost all of them are covered by a certain form. Therefore, the heat dissipation effect is low and must be met. Therefore, in the present invention, as described above, the vent ports 14a and 14b and the communication port 14c are provided in the center conductor 13 of the bushing 10. The bushing portion 10 is circulated through the bushing 10 The electric current of the center conductor 13 is increased, but the air is sucked and discharged from the vents 14a and 14b. The main circuit connecting portion 13b is cooled, and the terminal connecting portion 13a side is also subjected to heat conduction. It is also cooled. Further, by providing the communication port 14c, as shown in Fig. 4, the communication port 14c is connected to the vent holes 14a, 14b, and air is formed from the back side of the fixed frame 1 to the accommodating side of the vacuum circuit breaker 2 Since the air flows, for example, as shown by the arrow, the connection portion between the terminal connecting portion and the contact of each main circuit terminal can be directly cooled. Further, the air inside the circuit breaker can be inhaled/exhausted via the upper and lower bushes 10, 11 and a higher cooling effect can be obtained. Further, 'the vent hole and the communication port are provided in the center conductor 13 belonging to the current-carrying portion. The vent ports and the communication ports are all opened in a direction inaccessible to a human finger or the like. Therefore, the safety of the energized portion (protection level) is met. At the same time, it can also meet the completeness (protection level) of the vent and communication port for inhaling/exhausting air. Further, in the above description, the shape of the main circuit connecting portion 13b of the center conductor 13 is formed in a rectangular shape when viewed in the axial direction, but is not limited thereto and may be circular. At this time, the tubular portion 12a may be formed as a cylinder. Further, although the venting port is provided with two portions (Ua, 14b) in the horizontal direction and the vertical direction, any portion may be provided. Further, although the communication port 14c' is provided at the center of the terminal connecting portion 13a, the communication port 14c may not be provided when the energizing capacitance is small. As described above, the bush according to the first embodiment is disposed on the wall surface on the back side of the fixing frame on which the opening and closing device is placed, and has an insulating cylinder and a ten-core conductor in the center of the insulating cylinder. A main circuit terminal of the opening and closing device is connected to one end of the center conductor, and the main circuit conductor is connected to the other end of the center conductor. The insulating cylinder has a tubular portion and is located at one end side of the tubular portion and is fixed. a mounting portion of the center portion of the flange portion of the wall surface and the opening end of the other end side, wherein the center guide system has a terminal connecting portion that protrudes from the mounting portion toward the inner side of the tubular portion and is connected to the main circuit terminal, And a main circuit connecting portion of the main circuit conductor is connected to the outer end surface of the mounting portion, and a vent opening penetrating in a direction perpendicular to the axis of the center conductor is provided on the mounting portion side of the main circuit connecting portion. The energization portion is directly cooled by a simple configuration, and the temperature rise of the energization portion can be suppressed and the liner can be cooled efficiently. Further, since the vent hole is formed in a figure-like shape in the horizontal direction and the vertical direction, the air from the outside can be efficiently sucked/exhausted in the inside of the center conductor of the bushing, so that a high cooling effect can be obtained. Further, since the communication port that communicates from the vent port to the inner side of the tubular portion is provided at the center of the terminal connecting portion of the center conductor, the air on the opening and closing machine side can be sucked into the intake/exhaust air through the bushing, in particular It is possible to effectively cool the terminal contact portion where the temperature rises high. Thus, the temperature rise of the energized portion can be suppressed, and a high cooling effect can be obtained. (Second Embodiment) Fig. 5 is a perspective view showing a bushing according to a second embodiment of the present invention. Figure 6 is a side cross-sectional view of the bushing of Figure 5. The connection structure of the vacuum circuit breaker 2 included in the fixed frame 1 is the same as that of the first embodiment of the first embodiment. Therefore, the illustration and description are omitted, and the difference is 323009 11 201223046. The connection guide (10) of the electric machine n constituting the switchboard must sufficiently withstand the rated current, the rated short-time withstand current, and the rated peak withstand current. Further, the insulating support portion of the connecting conductor must be a supporting structure that sufficiently withstands the electromagnetic force at the time of short-circuit current power-on or the impact force at the time of opening and closing. According to the above reason, in the center conductor of the bushing, it is necessary to sufficiently secure the sectional area and securely fix it so as to be able to withstand the energization or impact force. In the structure of Fig. 3, which is described in the second embodiment of Fig. 1, the cooling effect can be sufficiently expected. However, from the above viewpoint, there is a need for further work. Therefore, in the second embodiment, as shown in Figs. 5 and 6, the vent hole provided in the center conductor 13 of the upper bushing 1 is provided only as a mounting surface of the main circuit connecting portion 13b in the vertical direction, for example. On the other hand, the vent hole 14a is provided with a ventilating opening in a direction parallel to the axis of the center conductor 13 in the upper and lower portions of the mounting portion 12c of the insulating cylinder 12 outside the outer circumference of the main circuit connecting portion 13b. Sew 15. The vent slit 15 is a condition that meets the safety (protection level) by setting the size (width) of a part of the human body (finger or the like). Next, the action of this configuration will be described. By providing the vent opening 14a with only a minimum of, for example, the vent opening provided in the center conductor 13 of the bushing, the current capacitance and the supporting portion (the terminal connecting portion 13a and the main circuit connecting portion 13b) can be hardly swayed. In the case of the strength of the portion, the cooling of the center conductor 13 is performed, and the vent slit 15 penetrating through the mounting portion 12c of the insulating cylinder 12 can be described in the fourth diagram of the embodiment 12 323009 201223046 Similarly, a flow path through the inside of the bushings 10 (and 11) and to the air on the vacuum circuit breaker side and the main circuit conductor side is formed, whereby the air inside the insulating frame 4 of the vacuum circuit breaker 2 can be sucked. Gas/exhaust and a higher cooling effect can be obtained. Further, since the ventilation slit 15 provided in the attachment portion 12c of the insulating cylinder 12 is formed in the axial direction of the insulating cylinder 12 (the pressing direction of the forming process), it is not necessary to perform special additional processing at the time of molding, and can be easily and inexpensively performed. Carry out the work. Further, in the above description, the ventilation slits 15 are provided in four places on the right and left sides of the main circuit connecting portion 13b, but may be, for example, two portions on the left and right or on the upper and lower sides. Further, the vent hole provided in the center conductor 13 may be provided in the horizontal direction, and if it is structurally (and electrically), it may be provided in two places in the vertical direction and the horizontal direction in the same manner as in the first embodiment. A communication port is provided at the center of the terminal connecting portion 13a. As described above, according to the bush of the second embodiment, in addition to the configuration of the first embodiment, the venting slit that penetrates the axial direction of the center conductor is provided in the mounting portion of the insulating cylinder, and therefore, in addition to the effect of the first embodiment, The air intake/exhaust of the air on the machine side can be opened and closed, and a higher cooling effect can be obtained. Further, by minimizing the vent hole provided in the center conductor, it is possible to provide a bushing which secures the current capacitance of the center conductor and the strength of the support portion and which has a good cooling effect. Furthermore, since the vent slit is provided in the axial direction of the insulating cylinder, the production of the rim 13 323009 201223046 does not require special additional processing, and can be easily performed by molding. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side cross-sectional view showing a main circuit breaking portion of a vacuum circuit breaker to which a bush according to a first embodiment of the present invention is applied. Fig. 2 is a perspective view for explaining the bushing structure of Fig. 1. Figure 3 is a side cross-sectional view of the bushing of Figure 2. Fig. 4 is an explanatory view showing the flow of air using the wall surface of the bush of the first embodiment. Fig. 5 is a perspective view showing a bushing according to a second embodiment of the present invention. Figure 6 is a side cross-sectional view of the bushing of Figure 5. Figure 7 is a side cross-sectional view of a conventional bushing. [Main component symbol description] 1 Fixed frame 2 Vacuum circuit breaker 3 Carriage 4 Insulation frame 5 Vacuum valve 6 Upper main circuit terminal 7 Lower main circuit terminal 8 Contact piece 8a Contact piece 8b Ring spring 10 Upper ferrule 11 Lower bushing 12 Insulation cylinder 12a Tube portion 12b Flange portion 12c Mounting portion 13 Center conductor 13a Terminal connection portion 13b Main circuit connection portion 14a, 14b Vent port 14c Communication port 15 Venting slit 320009 14