200905113 九、發明說明 【發明所屬之技術領域】 本發明爲車輛等之煞車配管中用於管材連接部的擴口 連結構造。 【先前技術】 該種擴口型管接頭，是利用擴張管材末端的管接頭， 且在煞車之類的油壓回路中’廣泛運用於油壓機器與管材 之間的連接。該種擴口型管接頭的傳統例如第6圖所示。 在第6圖中，圖號10是表示於末端加工形成擴口部 的金屬製管材，圖號1 1則表示連接對象的油壓機器本 體。在該本體11開口形成有作爲連接埠之前端呈錐形的 螺絲孔（以下簡稱爲錐形螺絲孔）12，且錐形螺絲孔12 通往油路14。圖號14爲形成於管材10前端的擴口部。圖 號1 5則是本體1 1側呈錐狀的密封面。 在管材1 〇外嵌有擴口螺帽1 7。在錐形螺絲孔1 2形成 有：可供擴口螺帽1 7之公螺紋螺合的母螺紋。因此，形 成可藉由鎖緊擴口螺帽17，而使管材1〇的擴口部14壓接 於密封面1 5。 管材10的擴口部14，是利用將末端擴張成圓錐狀的 擴口加工所形成。該擴口部14，其擴口密封面l4a是壓接 於所配合的密封面1 5而形成有效的密封。該種單擴口型 之擴口部14的規格，是依據ISO的標準。本出願人在特 許文獻1中，揭示一種ISO型之擴口連結構造的改良。 200905113 在擴口連結構造中，除了單擴口型之外，還具有如第 7圖所示之JASO標準的雙重擴口型的擴口部20。該雙重 擴口型的擴口部20 ’是執行兩次擴口加工的產物。 [專利文獻1]日本特開2005-214254號公報 【發明內容】 [發明欲解決之課題] 由於IS Ο型的擴口連結構造是形成：按壓擴口部1 4 而緊密貼著於密封面1 5的構造，故將因爲擴口螺帽1 7的 鎖緊方式而使密封性能有所不同。一旦擴口螺帽17未鎖 緊，將使壓接於密封面1 5的密封面壓降低，而導致密封 性能不足。相反地，一旦以過量的扭矩來鎖緊擴口螺帽 1 7，將如第 8圖所示，使擴口部14壓潰而產生大量變 形，導致擴口密封面1 4a從密封面1 5脫離而使密封面壓 下降。特別是當利用不易控制扭矩的氣動工具來旋鎖擴口 螺帽時，將因爲過量扭矩而形成過度鎖緊，其結果多半是 招致密封性能下降。 在ISO型的擴口連結構造中，除了擴口螺帽17之過 度鎖緊的問題以外，當利用擴口螺帽1 7使擴口部1 4壓接 於密封面1 5時，由於擴口部1 4是面接觸於密封面，因此 原本就具有難以確保高密封面壓的問題。 不僅如此，當鎖緊擴口螺帽1 7後，有時管材1 0將因 爲某些原因而略微轉動。在該場合中，擴口螺帽17是與 管材1 0 —起轉動，長時間下來將衍生出擴口螺帽1 7鬆 -5- 200905113 弛、密封性能下降的問題。 有鑑於此，本發明的目的是提供一種管材的擴口連結 構造，該管材的擴口連結構造可解決前述傳統技術所具有 的問題點，並可防止當以過量的扭矩鎖緊擴口螺帽、或管 材傾斜插入時之局部面壓下降的情形，且能確保更高密封 面壓。 此外，本發明的另一個目的是提供一種管材的擴口連 結構造，該管材的擴口連結構造不易使管材與擴口螺帽一 起轉動，可防止長時間下來密封性能的下降。 [解決問題之手段] 爲達成前述的目的，本發明是在金屬製管材的末端形 成擴口部’並將管材末端插入配合構件的錐形螺絲孔，再 藉由將擴口螺帽旋鎖入前述錐形螺絲孔，而使前述擴口部 按壓於前述錐形螺絲孔底面之密封面的管材的擴口連結構 造，其特徵爲：用來密封前述錐形螺絲孔底面的密封面之 前述擴口部的密封面、與被擴口螺帽前端所按壓之前述擴 口部背面的被按壓面，兩者的中心都是在與前述管材之軸 心相同的軸上’並配置在具有大致相同半徑的圓上。 此外，本發明當前述管材的外徑爲Di(mm)、前述 擴口部的最大外徑爲D2(mm)、前述擴口部之前端的内 徑爲D3 (mm)時’前述擴口部是具有遵循IS〇標準之形 狀的ISO型，其特徵爲： 200905113 (D,-l-2) ^ D4 ^ 0.8 此外，當前述管材的外徑爲Di ( ) '前述擴口部 的最大外徑爲D2 ( mm )、前述擴口部之前端的内徑爲D3 (mm )時，前述擴口部爲具有反折形狀的雙重擴口型’ 其特徵爲： (Di-1.2)^D4^〇.8 Da 此外，前述擴口部的密封面是形成球面° 此外，特徵爲：當前述球面的球半徑爲R時’ R ^ Di/2 此外，用來密封前述錐形螺絲孔前述底面的前述密封 面之前述擴〇部的前述密封面是形成球面狀。 不僅如此，本發明的特徵爲：在前述錐形螺絲孔底面 的密封面中，於前述擴口部之密封面所按壓的密封區域以 外形成凹凸部。 此外，前述凹凸部是位在：當前述擴口部的前述密封 面按壓於前述錐形螺絲孔的底面時之有效密封區域的外 側，也就是指擴口部側之密封區域的外側。 此外，前述擴口螺帽之軸方向的鎖緊力爲200 0N以 上0 200905113 根據本發明’可防止當以過量的扭矩鎖緊擴 時、或管材傾斜地插入時之局部性的面壓下降，並 更高的密封面壓。 此外，使得管材與擴口螺帽很難一起轉動，可 擴口螺帽緩緩地鬆弛所引發之長時間的密封性能下丨 【實施方式】 以下，針對本發明之管材的擴口連結構造的 態，參考圖面進行說明。 第1實施形態 第1圖，是顯示本發明第1實施形態之擴口連 的剖面圖。在該第1圖中，圖號10爲金屬製的管 號爲連接對象的油壓機器本體。該本體11形成 螺絲孔1 2，而該錐形螺絲孔1 2連通於油路1 4。在 絲孔1 2的底面，形成有呈錐狀的密封面1 5 °在管木 嵌著擴口螺帽17，該擴口螺帽17是形成：螺合於 錐形螺絲孔1 2的母螺紋。 在管材1 0的末端，是藉由擴口加工而形成有 的擴口部3 0。在本實施形態中，擴口部3 〇基本上 具反折形狀之單擴口型的擴口部爲基礎’並附加以 徵。 管材1 0的擴口部3 0是由以下的3個部分所形 端部3 1 ;和第1曲折部3 2，該第1曲折部3 2是連 口螺帽 可確保 防止因 實施形 結構造 材，圖 有錐形 錐形螺 ί 10外 形成在 圓錐狀 是以不 下的特 成：前 接於該 -8 - 200905113 前端部31;及第2曲折部33。在第1圖中’D!爲管材l〇 的外徑。D2爲擴口部3 0的最大外徑’ D3爲前端部3 1的 内徑。 在擴口部3 0，於前端部3 1的外側面，從前端起以特 定的S所標示的圓環狀區域形成密封面。另外’在第1曲 折部3 2的背面，以寬度S ’所標示的圓環狀區域則成爲接 觸於擴口螺帽1 7前端並形成按壓的被按壓面。接著，密 封面S的區域與被按壓面S ’的區域，彼此的中心均位在與 管材1 〇之軸心L相同的軸上，並配置在具有大致相同之 半徑的圓上。也就是說，擴口部3 0的密封面S，其中心 位於管材1 0的軸心L且配置在半徑爲R的圓上，而位在 被擴口螺帽1 7前端所按壓之擴口部3 0背面的被按壓面 s ’’也同樣是中心位於管材1 〇的軸心L且配置在半徑爲 R的圓上。 密封面S與被按壓面S，呈現具有一定寬度的環狀形 狀’幾乎是相當於以管材1 〇之軸心L作爲軸心的圓錐台 的側面。所謂「密封面S與被按壓面S ’，各自的中心均位 在與管材1 0之軸心L相同的軸上，並配置在大致與半徑 R相等的圓上」是指：密封面S之寬度的中心部與被按壓 面S ’之寬度的中心部是分別配置在大致等於半徑R的圓 上。此外，文中所述的「大致相同」是指：密封面S的寬 度範圍與被按壓面S’的寬度範圍在半徑方向上重疊，最好 是上述寬度範圍重疊50%以上。 再者，在密封面S的寬度與被按壓面S，的寬度遠低於 -9- 200905113 半徑R的場合中，幾乎可忽略密封面S的寬度與被按壓面 S ’的寬度，密封面S與被按壓面S ’的形狀是近似於圓環， 在該場合中上述兩者均是位在同一半徑R的圓上。 接下來，針對構成上述構造之本實施形態的作用及效 果進行說明。 在第1圖中，是將管材10的末端插入配合構件也就 是指油壓機器本體1 1的錐形螺絲孔1 2。當擴口螺帽1 7旋 鎖入錐形螺絲孔1 2時，擴口螺帽1 7的前端將抵接於擴口 部3 0的背面。當更進一步旋鎖擴口螺帽1 7時，擴口部3 0 的密封面S將按壓錐形螺絲孔1 2底面的密封面1 5，而形 成有效地密封。 根據本實施形態，由於是具有「密封面S與被按壓面 S ’各自的中心是位在與管材1 0之軸心L相同的軸上且配 置在大致與半徑R相等的圓上」的構造，故由擴口螺帽 17所作用的按壓力將不會分散地，集中作用於直接將擴口 部30的密封面S壓接於密封面15的壓接作用，如此一 來，可確保高密封面壓。因此，即使是使用氣動工具等不 易管理扭矩的工具來鎖緊擴口螺帽1 7，也能卻實地獲得充 分的密封性能。 此外，由於具有「密封面S與被按壓面S，各自的中心 是位在與管材10之軸心L相同的軸上且配置在大致與半 徑R相等的圓上」的構造’因此使作用於被按壓面S’之 力量中的絕大部分作用於密封面S，故可集中於密封作 用，而不會產生如第8圖所示因槓桿作用而使擴口部30 -10- 200905113 大量變形的情形。如此一來，即使在以過量的扭矩過度旋 鎖擴口螺帽1 7的場合中，由於擴口部3 0不會形成大量變 形，因此不會有密封面壓下降的情形，可確保高密封性 能。 在如同本實施形態之單擴口型的擴口連結構造中，根 據實驗的結果及經驗上的評估，倘若管材1 〇的外徑D i (mm)、擴口部30的最大外徑D2(mm)、擴口部30前 端的内徑D3 ( mm )之間存在以下的關係時： (D!-1.2)^D3^〇.8 D2 ... ( 1 ) 密封面S的區域及被按壓面的區域s ’，其中心是位在 與管材1 0之軸心L相同的軸上且配置在大致與半徑R相 同的圓上，密封面S的區域與被按壓面的區域S’可形成重 疊的構造。 其次，第2圖是顯示：以電腦模擬當改變擴口螺帽1 7 之軸方向的鎖緊力（N )時，密封面壓（N/cm2 )將產生何 種變化的圖表。在第2圖中，是針對符合計算式（1 )， 且D3= 0.65D2之尺寸的擴口連結構造進行模擬。該模擬 的結果是以實線來表示。 以虛線所表示的部分，是顯示針對第6圖所示的傳統 型擴口連結構造採用相同的條件執行模擬的結果。在第6 圖所示的傳統型擴口連結構造中，並不符合上述計算式 (1 )的條件，且密封面S的區域與被按壓面的區域S ’並 -11 - 200905113 未形成重疊關係。 在第2圖中，當鎖緊力（以下稱爲軸力）從零開始增 加時，密封面壓是上昇後急遽下降，並在軸力爲2000N左 右時形成最低。該狀況是從線接觸變化成面接觸所衍生的 現象。根據上述的現象，倘若以軸力2000N來鎖緊，應該 可獲得高密封面壓。話雖如此，但在現場作業中以實際的 擴口螺帽所執行的鎖緊步驟，是無法以不滿200 0N的軸力 來完成。現場作業中所呈現的結果是意味著：當以2000N 以上鎖緊時密封面壓的變化。因此，當著眼於第2圖中軸 力2 00 ON以上的範圍時，可由第2圖清楚的得知，相較於 傳統型的擴口構造，本實施形態的擴口構造的密封面壓更 高，具有更優良的密封性能。 第2實施形態 接著，針對本發明之第2實施形態的擴口連結構造， 參考第3圖進行說明。 該第2實施形態，是將本發明用於具有雙重擴口型之 擴口部3 0的管材的實施形態。雖然擴口部3 0是由：前端 部3 1 ;和連接於該前端部3 1的第1曲折部32 ;及第2曲 折部3 3的3個部分所形成的這點與單擴口型相同’但是 利用執行2次擴口加工’而使前端部3 1形成1 80。反折的 形狀。在第2圖中’ 〇,表示管材10的外徑。D2爲擴口部 3 〇的最大外徑，D 3則是前端部3 1的内徑。 在該雙重擴口型的擴口部30中’密封面S與被按壓 -12- 200905113 面s’是爲在第3圖中所示的位置。密封面S與被按壓面 S ’’各自的中心是位在與管材1 〇之軸心L相同的軸上， 且配置在大致與半徑R相等的圓上，而密封面8與被按壓 面S’在半徑方向上形成重疊的狀悲疋與桌1實施形態相 同。 根據上述的第2實施形態，與第1實施形態相同’即 使在以過量的扭矩來過度鎖緊擴口螺帽17的場合中，也 能確保高度的密封性能。 而在雙重擴口型的場合中，當管材10的外徑Di (mm )、擴口部30的最大外徑D2 ( mm )、前述擴口部 之前端的内徑D3 ( mm )之間存在以下的關係時： (0^1.0)^03^0.802 ... ( 2 ) 密封面S的區域與被按壓面S’的區域，其中心是位在 與管材1 0之軸心L相同的軸上並配置在大致與半徑r相 等的圓上，而可形成密封面S的區域與被按壓面的區域S， 重疊的構造。 第3實施形態 接著，針對本發明之第3實施形態的擴口連結構造， 參考第4圖進行說明。 該第4實施形態的擴口連結構造，是更進一步改良第 1實施形態之單擴口型擴口連結構造而成，其擴口部3 0的 -13- 200905113 密封面是形成球面的實施形態。在該擴口部3 0的場合中 是形成：從前端部3 1的外周面起至第1曲折部3 2的外周 面爲止，連接成大致相同半徑的球面。 不僅如此，當中心位於管材1 0的軸線上之球面的球 半徑爲R時，與管材1 0的外徑D!之間存在以下的關係： R ^ Di/2 ... ( 3 ) 而在該第3實施形態中，擴口部3 0之密封面的區域 S與被按壓面的區域S ’是與第1實施形態相同，並符合計 算式（1)的關係，也就是說：密封面s的區域與被按壓 面的區域S’的中心是位在與管材10之軸心L相同的軸上 且配置在大致與半徑R相同的圓上，而且密封面S的區域 與被按壓面的區域S’可形成重疊的構造。 根據上述的第3實施形態，除了可獲得第1實施形態 的作用效果之外，由於擴口部3 0的密封面S形成球面， 故即使是線接觸於密封面1 5的單擴口型擴口部3 0，也可 以藉由每個單位面積之密封力增大的線密封構造，確實地 確保更高的密封面壓。 此外，在末端具有擴口部3 0之管材1 〇的場合中，當 管材1 〇插入錐形螺絲孔1 2時’是對軸芯呈傾斜地插入。 在該場合中，當管材1 〇呈傾斜的狀態下鎖緊擴口螺帽1 7 時，將使擴口部3 0的密封面s不對稱地接觸於密封面i 5 (亦即非全面接觸），而具有擴口部30之整個外周無法 -14- 200905113 形成密封狀態。 但是，根據第3實施形態，由於擴口部3 0的密 S是形成球面，因此很難不規則地抵接於密封面1 5， 個外周可藉由線密封構造而確保高密封面壓。 第4實施形態 第5圖，是顯示本發明第4實施形態之擴口連結 的圖。 上述第1〜第3實施形態的擴口連結構造，主要 獲得高密封面壓之擴口部的密封構造，但以下所說明 4實施形態，是除了第1〜第3實施形態的擴口連結 之外，可更進一步防止管材10與擴口螺帽17 —起轉 單擴口型的擴口連結構造。 在第5圖中，於密封面15上，藉由沖床加工或 加工等所形成的凹凸部5 0是與錐形螺絲孔1 2同軸地 圓環狀。在該場合中，凹凸部50是配置在：作爲密 1 5而發揮作用之區域的外側。擴口部3 0的第1曲折= 是形成抵接於該凹凸部5 0。擴口部3 0側的密封面S 凸部5 0之間的關係是形成：當被按壓於錐形螺絲孔 底面時，凹凸部5 0是位在有效密封的擴口部3 0側之 面S的區域外。換言之，擴口部30之密封面S的區 形成於內側，以避免與凹凸部5 0接觸。而在第5圖 雖然凹凸部50是形成在半徑方向上連接有凹凸，但 亦可連接於圓環狀的圓周方向上。 封面 故整 構造 是可 的第 構造 動之 滚花 形成 封面 形32 與凹 2的 密封 域是 中， 凹凸 -15- 200905113 根據上述的第4實施形態，當鎖入擴口螺帽1 7時， 擴口部3 0的密封面s被按壓於錐形螺絲孔1 2底面的密封 面1 5，並使密封面S的外側被壓接於凹凸部5 0而變的緊 密。如此一來，可使出現於擴口部3 0與密封面1 5之間的 摩擦係數顯著增加。因此，無論以任何的原因對管材1 0 作用轉動力，管材也不會轉動，如此一來，可防止因轉動 而造成擴口螺帽1 7的鬆弛。據此，在旋鎖管材1 〇後，可 長時間維持開始時的密封性能。 【圖式簡單說明】 第1圖：爲顯示本發明第1實施形態之擴口連結構造 的縱剖面圖。 第2圖：是顯示模擬本發明第1實施形態之擴口連結 構造中’當鎖緊力改變時之密封面壓的變化結果的圖表。 第3圖：爲顯示本發明第2實施形態之擴口連結構造 的縱剖面圖。 第4圖：爲顯示本發明第3實施形態之擴口連結構造 的縱剖面圖。 第5圖：爲顯示本發明第4實施形態之擴口連結構造 的縱剖面圖。 第ό圖：爲傳統擴口連結構造的縱剖面圖。 第7圖：爲雙重擴口型之擴口部的縱剖面圖。 第8圖：爲顯示傳統擴口連結構造之問題點的縱剖面 圖0 -16- 200905113 【主要元件符號說明】 1 0 :管材 1 1 :油壓機器本體 1 2 :錐形螺絲孔 1 4 :油路 1 5 :密封面 1 7 :擴口螺帽 3 0 :擴口部 3 1 :前端部 3 2 :第1曲折部 3 3 :第2曲折部 S :密封面 S ’ ：被按壓面[Technical Field] The present invention relates to a flared connection structure for a pipe joint portion of a brake pipe for a vehicle or the like. [Prior Art] This type of flared pipe joint utilizes a pipe joint at the end of a pipe, and is widely used in a hydraulic circuit such as a brake to be used for connection between a hydraulic machine and a pipe. A conventional example of such a flared pipe joint is shown in Fig. 6. In Fig. 6, reference numeral 10 denotes a metal pipe material which is formed at the end to form a flared portion, and Fig. 1 1 shows a hydraulic machine body to be connected. A screw hole (hereinafter simply referred to as a tapered screw hole) 12 which is tapered at a front end of the connecting port is formed in the opening of the body 11, and the tapered screw hole 12 leads to the oil passage 14. Figure 14 is a flared portion formed at the front end of the pipe 10. Figure 15 is a sealing surface having a tapered shape on the body 1 1 side. A flared nut 17 is embedded in the pipe 1 〇. The tapered screw hole 12 is formed with a female thread for screwing the male screw of the flared nut 17. Therefore, it is formed that the flared portion 14 of the tubular member 1 is crimped to the sealing surface 15 by locking the flared nut 17. The flared portion 14 of the pipe 10 is formed by a flared process in which the tip is expanded into a conical shape. The flared portion 14 has a flared sealing surface 14a that is crimped to the mating sealing surface 15 to form an effective seal. The specifications of the flared portion 14 of the single flare type are in accordance with the ISO standard. In the present document 1, the present applicant discloses an improvement of an ISO type flare connection structure. 200905113 In the flare connection structure, in addition to the single flare type, there is a double flare type flare portion 20 of the JASO standard as shown in Fig. 7. The double flared flared portion 20' is a product that performs two flare processes. [Patent Document 1] Japanese Laid-Open Patent Publication No. 2005-214254 [Draft of the Invention] [Problem to be Solved by the Invention] The IS-type flared connection structure is formed by pressing the flared portion 14 and closely adhering to the sealing surface 1 The construction of 5, so the sealing performance will be different because of the locking mode of the flared nut 17. Once the flared nut 17 is unlocked, the sealing surface pressure crimped to the sealing surface 15 will be lowered, resulting in insufficient sealing performance. Conversely, once the flared nut 17 is locked with an excessive amount of torque, as shown in Fig. 8, the flared portion 14 is crushed to cause a large amount of deformation, resulting in the flared sealing surface 14a from the sealing surface 15 The detachment causes the sealing surface pressure to drop. In particular, when a pneumatic tool that does not easily control the torque is used to lock the flared nut, excessive locking is caused by excessive torque, and as a result, the sealing performance is likely to be degraded. In the ISO-type flared connection structure, in addition to the problem of excessive locking of the flared nut 17, when the flared portion 14 is crimped to the sealing surface 15 by the flared nut 17, due to the flare Since the portion 14 is in surface contact with the sealing surface, there is a problem that it is difficult to secure a high sealing surface pressure. Moreover, when the flare nut 17 is locked, sometimes the tube 10 will rotate slightly for some reason. In this case, the flared nut 17 rotates together with the pipe 10, and the flared nut is released for a long time, and the sealing performance is lowered. In view of the above, an object of the present invention is to provide a flared joint structure of a pipe material, the flared joint structure of the pipe material can solve the problems of the aforementioned conventional technology, and can prevent the flare nut from being locked when the torque is excessively excessive. Or, when the pipe is tilted, the partial surface pressure is lowered, and a higher sealing surface pressure can be ensured. Further, it is another object of the present invention to provide a flared joint structure of a pipe material which has a flared joint structure which is less likely to cause the pipe to rotate together with the flared nut, thereby preventing a decrease in sealing performance over a long period of time. [Means for Solving the Problem] In order to achieve the above object, the present invention is to form a flared portion at the end of a metal pipe and insert the end of the pipe into a tapered screw hole of the fitting member, and then screw the flared nut into the hole. a flared connection structure of the tubular material, wherein the flared portion is pressed against a sealing surface of the bottom surface of the tapered screw hole, and the expansion surface of the sealing surface for sealing the bottom surface of the tapered screw hole The sealing surface of the mouth and the pressed surface of the back surface of the flared portion pressed by the tip end of the flared nut are both disposed on the same axis as the axis of the pipe and are disposed substantially the same On the circle of the radius. Further, in the present invention, when the outer diameter of the pipe is Di (mm), the maximum outer diameter of the flared portion is D2 (mm), and the inner diameter of the front end of the flared portion is D3 (mm), the aforementioned flared portion is ISO type having a shape conforming to the IS〇 standard, characterized in that: 200905113 (D, -l-2) ^ D4 ^ 0.8 Further, when the outer diameter of the aforementioned pipe is Di ( ) ', the maximum outer diameter of the flared portion is When D2 (mm) and the inner diameter of the front end of the flared portion are D3 (mm), the flared portion is a double flare type having a reversely folded shape. The feature is: (Di-1.2)^D4^〇.8 Further, the sealing surface of the flared portion is formed into a spherical surface. Further, when the spherical radius of the spherical surface is R, 'R ^ Di/2, the sealing surface for sealing the bottom surface of the tapered screw hole The sealing surface of the expanded portion is formed in a spherical shape. Further, the present invention is characterized in that, in the sealing surface of the bottom surface of the tapered screw hole, the uneven portion is formed outside the sealing portion pressed by the sealing surface of the flared portion. Further, the uneven portion is located outside the effective sealing region when the sealing surface of the flared portion is pressed against the bottom surface of the tapered screw hole, that is, the outer side of the sealing portion on the flared portion side. In addition, the locking force of the aforementioned flared nut in the axial direction is 200 0N or more. 200905113 According to the present invention, it is possible to prevent localized partial pressure drop when the tire is locked with excessive torque or when the pipe is obliquely inserted, and Higher sealing surface pressure. In addition, it is difficult for the pipe and the flared nut to rotate together, and the long-term sealing performance caused by the flared nut is gradually relaxed. [Embodiment] Hereinafter, the flaring structure of the pipe of the present invention is State, refer to the figure to illustrate. (First Embodiment) Fig. 1 is a cross-sectional view showing a flare joint according to a first embodiment of the present invention. In the first drawing, reference numeral 10 denotes a hydraulic machine body to which a metal pipe number is to be connected. The body 11 forms a screw hole 12, and the tapered screw hole 12 communicates with the oil passage 14. A tapered sealing surface is formed on the bottom surface of the wire hole 12, and a flared nut 17 is embedded in the tube wood. The flared nut 17 is formed by a female screwed into the tapered screw hole 12 Thread. At the end of the pipe 10, a flared portion 30 formed by flaring is formed. In the present embodiment, the flared portion 3 is basically based on a single flared flared portion having a reversely folded shape. The flared portion 30 of the pipe 10 is an end portion 3 1 formed by the following three portions; and a first meander portion 32, which is a joint nut to ensure prevention of the configuration The material is formed by a tapered conical yoke 10 which is formed in a conical shape. The front end portion 31 is connected to the -8 - 200905113; and the second bent portion 33 is formed. In Fig. 1, 'D! is the outer diameter of the pipe l〇. D2 is the maximum outer diameter 'D3 of the flared portion 30' is the inner diameter of the tip end portion 31. In the flared portion 30, on the outer side surface of the front end portion 31, a sealing surface is formed from an annular region indicated by a specific S from the tip end. Further, the annular region indicated by the width S ′ on the back surface of the first bent portion 3 2 is a pressed surface that contacts the tip end of the flared nut 17 and forms a press. Next, the region of the cover S and the region of the pressed surface S' are positioned on the same axis as the axis L of the tube 1 ,, and are disposed on a circle having substantially the same radius. That is, the sealing surface S of the flared portion 30 has a center located at the axis L of the tube 10 and disposed on a circle having a radius R, and is flared at the front end of the flared nut 17 Similarly, the pressed surface s '' on the back surface of the portion 30 is located at the center L of the tube 1 且 and is disposed on a circle having a radius R. The sealing surface S and the pressed surface S have an annular shape having a constant width, which is almost the side surface of the truncated cone having the axis L of the tube 1 作为 as the axis. The "sealing surface S and the pressed surface S' are each positioned on the same axis as the axis L of the tube 10 and disposed on a circle substantially equal to the radius R" means: the sealing surface S The center portion of the width of the center portion of the width and the pressed surface S' is disposed on a circle substantially equal to the radius R. Further, "substantially the same" as used herein means that the width of the sealing surface S overlaps the width of the pressed surface S' in the radial direction, and it is preferable that the width range overlaps by 50% or more. Further, in the case where the width of the sealing surface S and the width of the pressed surface S are much lower than the radius R of -9-200905113, the width of the sealing surface S and the width of the pressed surface S' are almost negligible, and the sealing surface S The shape of the pressed surface S' is approximately a circular ring, in which case both of the above are on a circle of the same radius R. Next, the action and effect of the present embodiment constituting the above configuration will be described. In Fig. 1, the insertion of the end of the pipe 10 into the mating member means the tapered screw hole 12 of the hydraulic machine body 11. When the flared nut 17 is screwed into the tapered screw hole 12, the front end of the flared nut 17 will abut against the back of the flared portion 30. When the flared nut 17 is further twisted, the sealing surface S of the flared portion 30 will press the sealing surface 15 of the bottom surface of the tapered screw hole 12 to form an effective seal. According to the present embodiment, the structure in which "the center of each of the sealing surface S and the pressed surface S' is positioned on the same axis as the axis L of the tube 10 and disposed on a circle substantially equal to the radius R" is used. Therefore, the pressing force applied by the flared nut 17 will not be dispersed, and the centrifugal action of directly pressing the sealing surface S of the flared portion 30 against the sealing surface 15 can be ensured, thereby ensuring high density. The cover is pressed. Therefore, even if a tool such as a pneumatic tool that does not manage the torque is used to lock the flare nut 17, it is possible to obtain sufficient sealing performance in the field. Further, since the "sealing surface S and the pressed surface S are provided, the center of each of the sealing surfaces S and the pressed surface S is located on the same axis as the axis L of the tube 10 and is disposed on a circle substantially equal to the radius R". Most of the force of the pressed surface S' acts on the sealing surface S, so that the sealing action can be concentrated without causing a large deformation of the flared portion 30-10-200905113 due to the lever action as shown in Fig. 8. The situation. In this way, even in the case where the flared nut 17 is excessively twisted with an excessive torque, since the flared portion 30 does not undergo a large amount of deformation, there is no possibility that the sealing surface pressure is lowered, and a high seal can be ensured. performance. In the flared joint structure of the single flare type as in the present embodiment, based on the experimental results and empirical evaluation, the outer diameter D i (mm) of the pipe 1 、 and the maximum outer diameter D2 of the flared portion 30 ( (mm), when there is the following relationship between the inner diameter D3 (mm) of the front end of the flared portion 30: (D!-1.2)^D3^〇.8 D2 (1) The area of the sealing surface S is pressed The area s ' of the surface is located on the same axis as the axis L of the tube 10 and is disposed on a circle substantially the same as the radius R. The area of the sealing surface S and the area S' of the pressed surface can be formed. Overlapping construction. Next, Fig. 2 is a graph showing a change in the sealing surface pressure (N/cm2) when the locking force (N) in the axial direction of the flare nut 17 is changed by a computer simulation. In Fig. 2, a simulation is made for a flared connection structure that conforms to the formula (1) and D3 = 0.65D2. The result of this simulation is expressed in solid lines. The portion indicated by the broken line shows the result of performing the simulation under the same conditions for the conventional flared joint structure shown in Fig. 6. In the conventional flared joint structure shown in Fig. 6, the condition of the above formula (1) is not satisfied, and the region of the seal surface S does not overlap with the region S 'and -11 - 200905113 of the pressed surface. . In Fig. 2, when the locking force (hereinafter referred to as the axial force) increases from zero, the sealing surface pressure rises sharply and then falls, and the lowest is formed when the axial force is about 2000 N. This condition is a phenomenon derived from a change in line contact to a surface contact. According to the above phenomenon, if the shaft force is locked by 2000N, a high sealing surface pressure should be obtained. Having said that, the locking step performed by the actual flared nut in the field operation cannot be completed with an axial force of less than 200 N. The results presented in the field work mean that the sealing surface pressure changes when locked above 2000N. Therefore, when focusing on the range of the axial force of 200 00 ON or more in Fig. 2, it can be clearly seen from Fig. 2 that the sealing surface pressure of the flared structure of the present embodiment is higher than that of the conventional flared structure. , with better sealing performance. Second Embodiment Next, a flare connection structure according to a second embodiment of the present invention will be described with reference to Fig. 3 . The second embodiment is an embodiment in which the present invention is applied to a pipe material having a flared portion 30 of a double flare type. The flared portion 30 is formed by the front end portion 3 1 and the first bent portion 32 connected to the front end portion 31 and the three portions of the second bent portion 3 3 and the single flare type. Similarly, 'the second flaring process is performed', the front end portion 31 is formed to be 1800. Reflexed shape. In Fig. 2, '〇, the outer diameter of the pipe 10 is shown. D2 is the maximum outer diameter of the flared portion 3, and D3 is the inner diameter of the front end portion 31. In the double flared flared portion 30, the 'sealing surface S and the pressed surface -12-200905113' s' are the positions shown in Fig. 3. The center of each of the sealing surface S and the pressed surface S'' is located on the same axis as the axis L of the tube 1 ,, and is disposed on a circle substantially equal to the radius R, and the sealing surface 8 and the pressed surface S 'The sorrow of forming an overlap in the radial direction is the same as that of the table 1 embodiment. According to the second embodiment described above, it is the same as that of the first embodiment. Even in the case where the flare nut 17 is excessively locked with an excessive torque, the high sealing performance can be ensured. In the case of the double flare type, the outer diameter Di (mm) of the pipe 10, the maximum outer diameter D2 (mm) of the flared portion 30, and the inner diameter D3 (mm) of the front end of the flared portion are as follows. When the relationship is: (0^1.0)^03^0.802 (2) The area of the sealing surface S and the area of the pressed surface S' are centered on the same axis as the axis L of the tube 10 It is disposed on a circle substantially equal to the radius r, and can form a structure in which the region of the sealing surface S and the region S of the pressed surface overlap. Third Embodiment Next, a flare connection structure according to a third embodiment of the present invention will be described with reference to Fig. 4 . In the flared connection structure of the fourth embodiment, the single-flare-type flared connection structure of the first embodiment is further improved, and the sealing surface of the flared portion 30 is a spherical surface. . In the case of the flared portion 30, a spherical surface having substantially the same radius is formed from the outer peripheral surface of the distal end portion 31 to the outer peripheral surface of the first meandering portion 32. Moreover, when the spherical radius of the spherical surface centered on the axis of the pipe 10 is R, the following relationship exists with the outer diameter D! of the pipe 10: R ^ Di / 2 ... ( 3 ) In the third embodiment, the region S of the sealing surface of the flared portion 30 and the region S' of the pressed surface are the same as in the first embodiment, and conform to the relationship of the calculation formula (1), that is, the sealing surface. The center of the region of s and the region S' of the pressed surface is located on the same axis as the axis L of the tube 10 and is disposed on a circle substantially the same as the radius R, and the region of the sealing surface S and the surface to be pressed The area S' can form an overlapping configuration. According to the third embodiment described above, the sealing surface S of the flared portion 30 forms a spherical surface in addition to the effect of the first embodiment, so that the single-flare type expansion of the line contact with the sealing surface 15 is achieved. The mouth portion 30 can also securely ensure a higher sealing surface pressure by a wire sealing structure in which the sealing force per unit area is increased. Further, in the case where the pipe material 1 〇 having the flared portion 30 at the end is inserted into the tapered screw hole 12 when the pipe 1 is inserted, the shaft core is inserted obliquely. In this case, when the flare nut 17 is locked in a state where the pipe 1 〇 is inclined, the sealing surface s of the flared portion 30 will be asymmetrically contacted to the sealing surface i 5 (ie, non-full contact) However, the entire outer circumference of the flared portion 30 cannot be sealed to a state of -14,051,051. However, according to the third embodiment, since the density S of the flared portion 30 is a spherical surface, it is difficult to irregularly abut against the sealing surface 15 and the outer peripheral surface can be secured by the wire sealing structure. Fourth Embodiment FIG. 5 is a view showing a flare connection according to a fourth embodiment of the present invention. In the flared connection structure of the above-described first to third embodiments, the sealing structure of the flared portion having a high sealing surface pressure is mainly obtained. However, the fourth embodiment described below is in addition to the flare connection of the first to third embodiments. Further, the pipe 10 and the flared nut 17 can be further prevented from being turned into a flared connection structure. In Fig. 5, on the sealing surface 15, the uneven portion 50 formed by punching or machining or the like is annularly coaxial with the tapered screw hole 12. In this case, the uneven portion 50 is disposed outside the region that functions as the dense member. The first meandering of the flared portion 30 is formed to abut against the uneven portion 50. The relationship between the convex surface 50 of the flared portion 30 side is such that when pressed against the bottom surface of the tapered screw hole, the uneven portion 50 is located on the side of the flared portion 30 of the effective seal. Outside the area of S. In other words, the region of the sealing surface S of the flared portion 30 is formed inside to avoid contact with the uneven portion 50. On the other hand, in the fifth embodiment, the uneven portion 50 is formed with irregularities in the radial direction, but may be connected to the annular circumferential direction. The cover structure is configurable, the knurling of the cover structure 32 and the recess 2 is the middle, and the concave and convex -15-200905113. According to the fourth embodiment described above, when the flare nut 17 is locked, The sealing surface s of the flared portion 30 is pressed against the sealing surface 15 of the bottom surface of the tapered screw hole 12, and the outer side of the sealing surface S is pressed against the uneven portion 50 to become tight. As a result, the coefficient of friction occurring between the flared portion 30 and the sealing surface 15 can be significantly increased. Therefore, the pipe does not rotate regardless of the rotational force acting on the pipe 10 for any reason, so that the slack of the flare nut 17 due to the rotation can be prevented. According to this, after the twisting of the pipe 1 ,, the sealing performance at the beginning can be maintained for a long time. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal sectional view showing a flare connection structure according to a first embodiment of the present invention. Fig. 2 is a graph showing a result of a change in the sealing surface pressure when the locking force is changed in the flared connection structure of the first embodiment of the present invention. Fig. 3 is a longitudinal sectional view showing a flare connection structure according to a second embodiment of the present invention. Fig. 4 is a longitudinal sectional view showing a flare connection structure according to a third embodiment of the present invention. Fig. 5 is a longitudinal sectional view showing a flare connection structure according to a fourth embodiment of the present invention. Figure: A longitudinal section of a conventional flared joint. Fig. 7 is a longitudinal sectional view showing a flared portion of a double flare type. Fig. 8: Longitudinal sectional view showing the problem of the conventional flared joint structure 0 - 16 - 200905113 [Description of main component symbols] 1 0 : Pipe 1 1 : Hydraulic machine body 1 2 : Taper screw hole 1 4 : Oil passage 1 5 : Sealing surface 1 7 : Flared nut 3 0 : Flared portion 3 1 : Front end portion 3 2 : First bent portion 3 3 : Second bent portion S : Sealing surface S ' : Pressed surface