201014983 六、發明說明： 【發明所屬之技術領域】 本發明是關於離心風扇，及搭載該離心風扇進行空氣 排出、供應的送風機器等空氣流體機械，更詳細地說，是 關於可在寬廣風量範圍獲得高效率的同時，還能夠降低該 離心風扇所產生之噪音的構成。 • 【先前技術】 先前的離心風扇，例如是揭示在以下專利文獻1，一 般’該先前的離心風扇’如附件的第11圖及第12圖所示 ，是由：與馬達旋轉軸連結的主板1;設置在該主板i相 向位置的環狀護罩2;及在主板1和護罩2之間，沿著周 方向隔著間隔設置的複數片葉片3所構成，接著，上述葉 片的前緣3a是比護罩的吸入徑位於內徑位置，另一方面 ，後緣3b是位於主板的外周緣位置。 β [專利文獻1]日本特開2003-206892號 【發明內容】 [發明欲解決之課題] 即，先前的離心風扇，從上述護罩2流入的空氣，會 在上述葉片3的表面產生流動分離的同時，在上述後緣側 3b產生與旋轉方向反向的逆流現象。該等分離現象和逆 流現象會經常產生，因此成爲導致效率降低或噪音增加的 原因。爲了降低該等現象造成的影響，上述葉片3和護罩 -5- 201014983 2的接合部，針對上述葉片3和上述主板1的接合緣部， 朝旋轉方向側彎曲形成接合，再加上，上述葉片33的前 端部是形成朝旋轉方向側傾斜。如此一來，就能夠成爲可 極力防止旋轉時上述葉片3的負壓面側產生分離現象和逆 流現象的構造。 一般，若要降低噪音，最有效的是降低離心風扇的旋 轉數，上述構成中，同樣地若使離心風扇的旋轉數降低， 則吹出空氣的靜壓會降低，然而，與此同時，恐怕會導致 _ 風量降低。因此，就期望能夠有一種不會導致風量降低， 並且，能夠降低噪音的離心風扇。 此外，上述離心風扇，所要求的運轉風量大多數爲1 個的狀況，因此，就以該所要求的運轉風量進行設計，藉 此實現高效率化及低噪音化。但是，所設計的風量和實際 的運轉狀態不同時，葉片的入口形狀就無法迎合吸入流。 因此，會從葉片前緣3a產生大規模的分離旋渦，使葉片 入口面積變窄的同時，使葉片3負壓面側的分離現象變大 φ ，產生大噪音，再加上，恐怕會造成送風效率降低。 於是，本發明是有鑑於上述先前技術的問題點，爲了 不僅能夠針對上述固定的風量，還能夠針對使用者所要求 的任意風量滿足低噪音和高效率，以提供一種即使是在寬 廣的風量運轉範圍，還是能夠抑制風扇內部的分離現象， 並且’高效率又低噪音的離心風扇爲目的，同時又以提供 一種使用該離心風扇之送風機器等的空氣流體機械爲目的 。即’提供一種能夠在寬廣運轉範圍抑制風扇內部的分離 -6 - 201014983 現象，實現高效率並且低噪音化的技術。 [用以解決課題之手段] 爲了達成上述目的，根據本發明時，首先，針對具備 有吸入口形成用環狀護罩和與該護罩成相向配置的主板及 在上述護罩和上述主板之間配置在周方向的複數葉片，可 使從軸方向吸取的空氣朝徑方向昇壓吐出的離心風扇，提 φ 供一種形成上述葉片其前緣形狀在軸方向大致中央位置具 有凹形狀部，並且，在上述主板及上述護罩側分別具有凸 形狀部的離心風扇。 此外，本發明是於上述所記載的離心風扇中，再加上 ，上述葉片是以上述護罩側的前緣比上述主板側的前緣還 位於旋轉方向的前方爲佳，又加上，上述葉片是以形成上 述葉片其接觸主板位置的葉片安裝角度會隨著該半徑位置 的增加具有2個反彎點的同時，其接觸上述護罩位置的葉 # 片安裝角度具有1個反彎點爲佳。再加上，上述葉片以形 成其後緣形狀是在旋轉方向具有凸形狀和凹形狀爲佳。 又加上’根據本發明時，又可提供一種在框體內形成 流路的同時，在該框體的一部份具備旋轉驅動手段的同時 ，在該旋轉驅動手段安裝上述離心風扇，藉此執行空氣排 出、供應的送風機器。 [發明效果] 根據上述的本發明的離心風扇和使用該離心風扇之空 201014983 氣流體機械時，能夠發揮下述優異效果，即，藉由能夠在 寬廣運轉範圍抑制風扇內部的分離現象，不僅能夠針對固 定的風量（設計點），還能夠針對使用者所要求的任意運 轉風量滿足低噪音和高效率，因此，能夠提供一種即使是 在寬廣的風量運轉範圍，還是能夠抑制風扇內部的分離現 象，並且，高效率又低噪音的離心風扇，同時又能夠提供 一種使用該離心風扇之送風機器等空氣流體機械。 【實施方式】 [發明之最佳實施形態] 以下，針對本發明的實施形態，一邊參照附圖的同時 ，加以詳細說明。 〈實施例1〉 首先，以本發明實施例1的離心風扇和使用該離心風 扇之空氣流體機械的一例，針對風扇濾器單元使用附件第 Θ 1圖〜第5圖進行詳細說明。 第1圖是表示本發明相關具有葉片之離心風扇17的 透視圖，第2(a)圖是表示其正面圖，第2(b)圖是表 示其側面圖。此外，第3圖是表示本發明相關離心風扇 17構成用的葉片3與護罩的接觸面（參照第4圖的3d) 及其與主板的接觸面（參照第4圖的3c)之葉片安裝角 度分佈圖表。再加上，第4圖是第1圖離心風扇17的葉 片3的側面圖，接著，附件的第5圖是圖示著以具備有上 -8- 201014983 述離心風扇17的流體機械爲實施例之風扇濾器單元13的 剖面圖。 首先’本發明相關的離心風扇17，如第1圖或第2( a)圖及第2(b)圖所示’具備：圓盤狀的主板1;及設 置在該主板1的相向位置，由平板素材形成爲圓環狀，其 中心部具有吸入口 4的護罩2，接著，該等主板1和護罩 2之間，是由在其圓周方向，隔著一定間隔設置的複數片 # (本例爲5片）葉片3所構成》 另外’上述葉片3，例如是使用金屬平板的素材形成 ’該葉片的壓力面是以平面，或者是以線形流暢的凹凸面 形成。此外’該等葉片3是利用分別設置在上述主板〗和 護罩2之間的固定構造（例如：包括鑲嵌構造或鉚接結合 )安裝。 此外，上述葉片3的前緣3a，如第1圖及第2(a) 圖所示’其與吸入口內徑側的護罩2的接觸部5a，相較 ® 於其與主板1的接觸部5b是位於旋轉方向的前方位置， 即向前傾斜著。 另一方面’上述葉片3的後緣3b，如第1圖及第2( a)圖所示’與上述護罩2的接觸部5c，相較於其與主板 1的接觸部5d是位於旋轉方向的前方位置。再加上，上 述葉片3的後緣3b是在葉片出口高度「Z」的大致丨/3位 ®形成朝旋轉方向前進的形狀。另外，本例是將該葉片出 □高度「Z」除以風扇外圍直徑「〇」後的風扇出口寬度 比Z/D爲〇.丨8，即，離心風扇的形態，爲了降低搭載有 201014983 該風扇的風扇濾器單元裝置高度，採用較小値的風扇出口 寬度比。 又加上，第2(a)圖中，畫一條對葉片3任意位置 和中心軸的連接直線6的正交線7，當該正交線7和葉片 3外面的切線8所形成的角度爲葉片安裝角度「/3」時， 如第3圖所示，主板內徑（即，主板1上的吸入口 4的內 徑側）的葉片3安裝角度是設定成比護罩最小內徑的葉片 安裝角度還大。接著，接觸於主板1的葉片3其安裝面 @ 3c的安裝角度「泠」，是如第3圖的實線曲線所示，隨 著朝向外徑（半徑R增大）逐漸增加角度而達到和葉片出 口角度（圖中以虛線直線表示，例如爲50° )大致相同 的角度，然後，以該點爲內徑側反彎點9a，下降至比主 板內徑的葉片角度還小的値爲止，到達外徑側反彎點9b 。接著，當超過該外徑側反彎點9b時，接觸於主板1的 葉片3其安裝面3c的安裝角度「0」是再度隨著朝向外 徑（半徑R增大）逐漸增加角度。即，接觸於主板1的葉 0 片3其安裝面3c的安裝角度分佈是設定成隨著朝向外徑 具有2個反彎點9a、9b。 其次，接觸於護罩2的葉片3其安裝面3d的安裝角 度是如第3圖的虛線曲線所示，隨著從護罩最小內徑朝向 外徑逐漸增加角度，以至面臨護罩反彎點10，然後，以 比接觸於主板1的葉片3其安裝面3c安裝角度增加還小 的比率朝向葉片出口角度（隨著半徑R增大）逐漸增加。 即’接觸於護罩2的葉片3其安裝面3d的安裝角度分佈 -10- 201014983 是設定成隨著朝向外徑具有1個反彎點10。 另外，從第3圖中明確得知，本實施例中，安裝角度 「冷」的上述護罩反彎點10到達，和上述主板1側的外 徑側反彎點9b的到達是可在大致同一徑的狀況下獲得， 更具體地說，針對風扇外圍直徑D是設定在可成爲大致 0.8 5D的位置。此外，主板1側的外徑側反彎點9b，藉由 將其葉片安裝角度「点」設定成比護罩反彎點1〇的安裝 〇 角度還小，可使主板側的負荷變小，藉此實現風扇內部的 流動一樣化。 再加上，上述葉片3的前緣形狀3a，如附件第4圖 所示，在葉片高度Η的大致中央位置（H/2)具有凹形狀 的同時’從該凹形狀部朝主板1側及護罩2側，分別具有 凸形狀。即，根據該葉片3的前緣形狀3a時，形成爲從 主板1朝向護罩2(即，朝其高度方向），一旦，使其半 徑[參照第2 ( a)圖的圖號6]變小，然後，在葉片高度的 ® 一半變大’接著’再度，使其半徑若干變小，然後至護罩 爲止半徑增加的形狀，換句話說，葉片3的前緣形狀3a ，具有類似希臘文字“ε”的形狀。 此外’上述葉片3的前緣形狀3a，又如上述第4圖 所示’主板1側中凸部形成部份的從該主板1往上昇的角 度是設定成與護罩2側中凸部形成部份的朝該護罩側往下 降的角度大致相同’其一例，本實施例是對吸入口形成面 平行的水平面成大致45。的角度。 根據以上所述之離心風扇1 7的構成時，針對設計時 -11 - 201014983 所設定的風量點，上述葉片3的前緣形狀3a，其在護罩2 側的位置是比在主板1側的位置還位於旋轉方向前方的位 置，即，藉由向前傾斜，能夠適當因應吸入流的速度分佈 ，藉此就能夠使流動不易在護罩側分離。 再加上，除上述之外，如以上所述’藉由對上述葉片 3的葉片安裝角度（即，上主板1側和護罩2側之安裝面 3c、3d的安裝角度「乃」，參照第3圖），採用反費點 (內徑側反彎點9a、外徑側反彎點9b、護罩反彎點10等 H )，能夠增加上述葉片3前半側的工作量及後半的工作量 ，同時還能夠使該葉片3內部的速度變化成爲一樣，藉此 能夠抑制葉片內部產生的分離現象。 又加上，特別是針對設計時未加以考慮之風量較小的 風量點，也是能夠藉由設置在上述葉片3前緣3a之形成 在高度方向大致中央位置的凹形狀部及分別設置在護罩2 側和主板1側的凸部，使先前離心風扇在其前緣所產生的 大規模分離旋渦往小規模分離旋渦縮小其規模，同時藉由 G 該分離旋渦分配在主板1側和護罩2側，還能夠抑制因該 旋渦形成受到遮蔽以致葉片入口緊接面積的降低。 即，根據上述構造所獲得的以上作用時，可提供一種 不僅能夠針對設計的風量點，特別是，即使針對又包括低 風量區的寬廣風量範圍，也能夠實現高效率暨低噪音的離 心風扇。 另外，根據以上的構成時，主板1和護罩2和複數片 葉片3之間形成有空氣流路，以指定的旋轉運轉該構成之 -12- 201014983 離心風扇17’能夠以其葉片3推出從吸入口 4流入的空 氣，藉此就能夠獲得指定的處理風量。 接著，附件的第5圖是圖示著以使用上述離心風扇之 空氣流體機械爲一例的風扇濾器單元。另，該風扇濾器單 元13是一種利用上述離心風扇17使空氣昇壓通過濾器 15，藉此使空氣中的塵埃或硼或磷等有機類氣體在該濾器 15去除的裝置。 φ 該風扇濾器單元13，從圖中亦可明確得知，基本上 ，其是由本體殼14和空氣清淨用的濾器15所構成，接著 ，該本體殻14設有馬達16固定用的馬達底座18，該馬 達的旋轉軸安裝有上述離心風扇17形成旋轉驅動。此外 ，本體殻14分別安裝有離心風扇17引流用的口環19’ 及對該離心風扇所送出的空氣流動進行整流的底板20。 即，根據該第5圖所示的風扇滤器單元時，可使來自 於大氣，或者是來自大氣中塵埃未去除之空間的空氣21 ❹ ，經由上述離心風扇17吸入內部’然後，可使從該離心 風扇17吐出的空氣流動’在馬達底座20和本體殻14內 壁所形成的流路內成爲一樣化’再加上’可使空氣衝撞本 體殼14內的側壁形成彎曲後’經由濾器15淨化’吹出至 欲空氣淨化的空間內° 其次，根據附件的第6圖’將經由利用上述本實施例 之離心風扇17的風扇濾器單元所獲得的試驗結果’例如 與上述第11圖及第12圖所示的先前離心風扇進行比較後 揭示在下述。另，該第6圖中’以風量爲橫軸’圖示著風 -13- 201014983 扇靜壓[第6(a)圖]、風扇靜壓效率[第6(b)圖] '噪音 級數[第6 ( c)圖]的試驗結果。 如該等第6(a)〜（c)圖所示，得知根據上述本實 施例的離心風扇1 7時，與先前品相比，其設計時之風量 點的靜壓並沒有改變，但靜壓效率卻增加，此外，噪音幾 乎相同。另一方面，又得知在比設計時風量點的風量還小 的區域，其靜壓增加及靜壓效率提昇。再加上，針對噪音 ，得知在比設計時風量點的風量還小的區域，可大幅降低 _ 噪音。即，從第6(a)〜（c)圖所示的結果，得知根據 本實施例時，不僅能夠針對設計時的風量點還能夠針對又 包括低風區的寬廣流量區域，實現離心風扇的高效率暨低 噪音化。 再加上，針對上述本實施例的離心風扇17，爲了調 查設計風量點效率獲得改善的效果，將數値解析的葉片升 力比較圖示在第7圖。另，該第7圖是根據模擬試驗狀態 的數値解析結果將葉片相關的升力（L)以相同半徑積分 @ 後所獲得的結果，根據該圖，可看出葉片的工作量。即， 從第7圖得知，相較於先前品，本實施例是半徑小但工作 量卻增加。此外，又得知隨著從半徑的大致中央部朝向外 徑，葉片的工作量即葉片升力（L)，雖然是降低至與先 前品相同程度，然而，在外側徑，終究工作量還是增加。 其原因是主板側的葉片安裝角度，因此只要改變葉片安裝 角度，就能夠使葉片的工作量增加提昇效率。 接著，針對上述本實施例的離心風扇1 7，特別是， -14- 201014983 針對在低風量區域能夠降低噪音的構造，即是針對上述葉 片3的前緣3A的形狀對流場造成的影響，使用第8圖進 行說明。第8 ( a )圖中，圖示著本實施例的非設計點風 量的葉片3之前緣3a附近的流動和旋渦的軌跡模式圖， 同時爲了進行比較，第8(b)圖中，圖示著先前品的流 動和旋渦的軌跡。另，該等第8(a)圖及第8(b)圖的 模式圖是以模擬試驗狀態後的數値解析結果爲依據的模式 φ 圖，從葉片3的前緣3a產生的分離旋渦11a的中心是以 虛線表示，並且，其周圍的流動12是以具有箭頭符號的 實線表示。 根據該等圖時，得知先前品[第8(b)圖]是從前緣 3a產生護罩2側分離旋渦11a，周邊的流動12會發達成 較大，在吸入口附近，阻塞葉片3的負壓面側。另一方面 ，得知本實施例[第8(a)圖]，根據形成從主板1朝向護 罩2，即於高度方向一旦其半徑[參照第2(a)圖的圖號 © 6]變小，然後，在葉片高度一半變大，接著，其半徑再度 若干變小，然後至護罩爲止半徑爲增加形狀的上述葉片3 的前緣形狀3a，即，根據類似“e”形狀的葉片3的前 緣3a的形狀時，可得知從葉片3的前緣形狀3a產生的分 離旋渦1 1是形成護罩側分離旋渦1 1 a和主板側分離旋渦 lib的2條。此外，又得知葉片3的前緣3a凸部所產生 的分離旋渦的周邊流動1 2是比先前品小，以致葉片負壓 面側的阻塞面積緩和，藉此能夠控制負壓面側的流動。 基於上述，根據本實施例1時，針對所設計的風量點 -15- 201014983 ，葉片3的吸入口 4其護罩的前緣5a是比其主板前緣5b 還位於旋轉方向的前方，因此能夠對應吸入流的速度分佈 ，藉此’使流動不易在護罩側分離。再加上，採用葉片安 裝角度的反彎點，因此能夠增加葉片前半側的工作量及其 後半的工作量，同時還能夠使該葉片內部的速度變化成爲 一樣，藉此能夠抑制葉片內部產生的分離現象。又加上， 特別是針對風量較小的非設計點，也是能夠透過形成在葉 片3的前緣3a之護罩2側和主板1側的凸部功能，使先 _ 前離心風扇在其前緣所產生的大規模分離旋渦分配在主板 側和護罩側，就能夠成爲小規模分離旋渦。即，縮小離心 風扇其前緣所產生分離旋渦的規模，藉此就能夠抑制葉片 3入口緊接之吸入面積的降低。 接著，根據以上的作用時，不僅是針對設計點，即使 是針對低風量區，都能夠實現離心風扇的高效率暨低噪音 化。此外，當風扇出口附近有障礙物等存在時，雖然會和 來自葉片的送出流形成干涉導致噪音增加，但葉片的後緣 @ 是斜置在周方向，因此其與該障礙物的流動千涉會產生時 間性偏差而能夠抑制葉片的高頻率音，藉此還能夠對噪音 其音色的改善有所貢獻。另外，特別是以使用上述離心風 扇之空氣流體機械爲一例的風扇濾器單元13，通常，因 是連續運轉數年，所以塵埃會附著在其濾器15，因此， 該濾器的壓損會逐年增加。即，基於此，風扇濾器單元會 在比設計點還低風量的狀態下形成運轉。然而，根據使用 上述本發明的離心風扇時，相較於先前的風扇，其噪音增 -16 - 201014983 加或效率降低較少，並且，在寬廣運轉範圍能夠維持高效 率，再加上，還能夠在省電化方面有所貢獻。 〈實施例2〉 接著，以下，針對本發明另一實施形態的實施例2, 使用第9圖進行說明。另，該第9圖，特別是表示本發明 相關具備有葉片的離心風扇17的側面圖。 從圖中也可明確得知，本實施例的離心風扇17是和 第1圖或第2圖同樣，具備有主板1，和設置在該主板1 相向位置的同時，由平板素材形成在其一部份具有吸入口 4的所謂護罩2，上述主板1和護罩2之間，再加上，是 由在圓周方向隔著一定間隔設置的複數片（本例爲5片） 的葉片3所構成。另，針對該葉片3,也是和上述同樣， 例如是使用金屬平板的素材形成，葉片的壓力面是以平面 或者是以線形流暢的凹凸面形成，接著，利用分別設置在 β 主板1和護罩2之間的固定構造（例如：包括鑲嵌構造或 鉚接結合）安裝。 此外，上述葉片3的吸入口徑4其護罩前緣5a是比 其主板前緣5b還位於旋轉方向的前方，向前傾斜著。再 加上，上述葉片的前緣形狀3a，又如上述第3圖所示， 在葉片高度Η的大致中央位置（H/2)具有凹形狀，主板 及護罩側具有凸形狀。即，其形狀是形成從主板朝向護罩 ，往高度方向，一旦先縮小半徑，然後到達葉片高度的一 半，半徑就變大，接著半徑再度若干變小，然後半徑增加 -17- 201014983 到達護罩爲止的形狀，前緣形狀是類似希臘文字的“ε” 形狀。 又加上，本實施例2中，特別是，上述葉片3的後緣 3b的護罩側，如第9圖所示，從主板1側至護罩2側， 針對旋轉方向設置凸部和凹部。即是形成在葉片出口高度 Z的大致1/2處具有反彎點，在主板側朝旋轉方向凸出， 並且，在護罩側凹陷的大致“S”字形狀。其理由是爲了 確保主板1側的工作量，即是和上述第2圖相同，形成爲 @ 朝旋轉方向凸出的形狀。此外，護罩2側的凹形狀，如上 述第8圖所示，是爲了更加抑制葉片3的前緣3a所產生 的護罩2側的分離旋渦成長，藉此使護罩2側的翼間面積 變小。 上述的葉片3的構成，如以上所述，針對所設計的風 量點，吸入口 4內徑的葉片3其護罩側的前緣5a是比其 主板側的前緣5b還位於旋轉方向前方[參照第1圖及第2 (a)圖]，即是形成爲向前傾斜著，因此能夠對應吸入流 _ 的速度分佈，使流動不易在護罩側分離。再加上，針對風 量小的非設計點，藉由形成在高度方向大致中央位置的凹 形狀3 a，和前緣的護罩側和主板側的各凸狀部（即，“ ε”形狀），能夠使先前離心風扇前緣所產生的大規模分 離旋渦縮小規模成小規模的分離旋渦，同時分配在主板側 和護罩側，因此就能夠抑制旋渦形成受到遮蔽以致葉片緊 接面積的降低。再加上，葉片3的後緣形狀3b是朝旋轉 方向形成爲凸形狀及凹形狀（即，“ S ”字形狀），所以 -18- 201014983 能夠引導旋渦，控制旋渦進入葉片3後的軌道，因此能夠 抑制葉片3的負壓面側所產生的分離現象。根據以上的作 用，不僅針對設計點，再加上，甚至是在低風量區，都能 夠實現離心風扇的高效率暨低噪音化。 根據以上的構成時，主板1和護罩2和複數片葉片3 之間形成有空氣流路，接著，以指定的旋轉運轉該構成之 離心風扇，能夠以其葉片3的葉片推出從吸入口 4流入的 〇 空氣獲得指定的處理風量。 利用附件第10(a)圖〜第10(C)圖，圖示著第2 實施例試驗結果和先前品的比較。另，該等圖中，圖示著 風量爲橫軸，另一方面，縱軸分別爲風扇靜壓[第10(a) 圖]、風扇靜壓效率[第10(b)圖]、噪音級數[第10(c) 圖]的試驗結果。從該等試驗結果也能夠明確得知，根據 上述實施例2的離心風扇時，與先前品相比，其設計點的 靜壓並沒有改變，但靜壓效率卻增加，並且，噪音是相同 ® 。此外，又得知在比設計時風量點風量還小的區域，其靜 壓增加及靜壓效率提昇。再加上，針對噪音，得知即使是 在比設計時風量點風量還小的區域，還是能夠和設計點相 同降低噪音。 即，從第10(a)〜（c)圖所示的結果，得知根據 本實施例時，不僅是針對設計點，即使是針對低風量區’ 還是能夠實現離心風扇的高效率暨低噪音化。此外’當障 礙物等位於風扇出口附近時，雖然會和葉片送出流形成干 涉導致噪音增加，但是，因葉片3的後緣3b是斜置在周 • 19 - 201014983 方向（即，“ S ”字形狀），所以與該障礙物的流動干涉 會產生時間性偏差能夠抑制葉片的高頻率音’藉此還能夠 對噪音其音色的改善有所貢獻。再加上，風扇濾器單元， 因是連續運轉數年，所以塵埃會附著在其濾器，因此，該 濾器的壓損會逐年增加。因此，風扇濾器單元會在比設計 點還低風量的狀態下形成運轉，但藉由使用本發明的離心 風扇，能夠比先前的風扇較能夠減少噪音的增加或效率的 降低’並且，在寬廣運轉範圍能夠維持高效率，因此，能 夠在省電方面有所貢獻。 以上’是以搭載在風扇濾器單元的離心風扇進行了實 施例的說明’但例如即使是使用在空調機器等其他的機器 ’還是能夠在寬廣運轉範圍維持高效率，能夠在省電方面 有所貢獻。 【圖式簡單說明】 第1圖爲表示本發明相關具有葉片之離心風扇（實施 φ 例1)的全體構造透視圖。 第2圖爲上述離心風扇（實施例i)的正面圖及側面 圖。 第3圖爲表示上述離心風扇（實施例1)的護罩及主 板接觸面的葉片安裝角度分佈圖。 第4圖爲上述離心風扇（實施例1)的葉片放大側面 圖。 第5圖爲具備有上述離心風扇（實施例1)的風扇漉 -20 - 201014983 器單元的剖面圖。 第6圖爲表示上述本發明離心風扇（實施例1)的風 量-靜壓特性、風量-效率特性、風量-噪音特性與先前離 心風扇的比較圖。 第7圖爲表示上述本發明離心風扇的升力特性經數値 解析後的結果與先前離心風扇的比較圖。 第8圖爲表示上述本發明相關離心風扇的前緣形狀在 φ 非設計點風量之狀況下所導致的旋渦和其發生規模與先前 離心風扇的比較模式圖。 第9圖爲表示上述本發明相關離心風扇（實施例2) 的側面圖。 第1〇圖爲表示上述離心風扇（實施例2)的風量-靜 壓特性、風量-效率特性、風量-噪音特性與先前離心風扇 的比較圖。 第11圖爲表示先前離心風扇的正面圖。 ® 第1 2圖爲表示先前離心風扇的側面圖。 【主要元件符號說明】 1 :主板 2 :護罩 3 :葉片 3a :前緣 3b :後緣 3c:葉片的接觸主板面 -21 - 201014983 3d:葉片的接觸護罩面 4 :吸入口 5 :吸入口的葉片位置 6 :葉片位置和中心軸的連結線 7 :連結線6的正交線 8 :葉片形狀的切線 9:葉片安裝角度的反彎點 9a :內徑側反彎點 @ 9b :外徑側反彎點 1 0 :護罩反彎點 11:在前緣產生的分離旋渦 1 1 a :護罩側分離旋渦 lib :轂側分離旋渦 1 2 :分離旋渦的周邊流 13 :風扇濾器單元 14 :本體殼 G 1 5 :濾器 1 6 :馬達 1 7 :離心風扇 1 8 :馬達底座 1 9 : 口環 20 :底板 -22-[Technical Field] The present invention relates to a centrifugal fan, and an air fluid machine such as a blower that discharges and supplies air by the centrifugal fan, and more particularly, relates to a wide air volume range. At the same time as high efficiency, the composition of the noise generated by the centrifugal fan can be reduced. • [Prior Art] The prior centrifugal fan is disclosed, for example, in Patent Document 1 below. Generally, the "previous centrifugal fan", as shown in Figs. 11 and 12 of the attachment, is composed of a main board coupled to a rotating shaft of the motor. 1; an annular shroud 2 disposed at a position opposite to the main board i; and a plurality of blades 3 disposed at intervals along the circumferential direction between the main plate 1 and the shroud 2, and then the leading edge of the blade 3a is located at the inner diameter position than the suction diameter of the shield, and the trailing edge 3b is located at the outer peripheral edge of the main plate. [Patent Document 1] Japanese Laid-Open Patent Publication No. 2003-206892 [Draft of the Invention] [Problems to be Solved by the Invention] In the prior centrifugal fan, air flowing in from the shroud 2 causes flow separation on the surface of the vane 3 At the same time, a reverse flow phenomenon opposite to the rotation direction is generated on the trailing edge side 3b. These separation phenomena and countercurrent phenomena are often generated, and thus cause a decrease in efficiency or an increase in noise. In order to reduce the influence of the above-described phenomenon, the joint portion between the blade 3 and the shroud-5-201014983 2 is bent and joined to the joint side of the blade 3 and the main plate 1 in the rotation direction side, and The front end portion of the blade 33 is formed to be inclined toward the rotation direction side. In this way, it is possible to prevent the separation phenomenon and the backflow phenomenon from occurring on the suction side of the vane 3 at the time of rotation as much as possible. In general, in order to reduce the noise, it is most effective to reduce the number of rotations of the centrifugal fan. In the above configuration, similarly, if the number of rotations of the centrifugal fan is lowered, the static pressure of the blown air is lowered. However, at the same time, Causes _ air volume to decrease. Therefore, it is desirable to have a centrifugal fan which does not cause a decrease in the amount of air and which can reduce noise. In addition, since the centrifugal fan has a required operating air volume of one of the most, it is designed with the required operating air volume, thereby achieving high efficiency and low noise. However, when the designed air volume is different from the actual operating state, the inlet shape of the blade cannot meet the suction flow. Therefore, a large-scale separation vortex is generated from the leading edge 3a of the blade, and the inlet area of the blade is narrowed, and the separation phenomenon on the negative pressure side of the blade 3 is made larger, causing a large noise, and, in addition, it may cause a blown air. Reduced efficiency. Accordingly, the present invention has been made in view of the above problems of the prior art, and in order to satisfy not only the above-described fixed air volume but also low noise and high efficiency for any air volume required by the user, to provide an operation even in a wide air volume. The scope is also capable of suppressing the separation phenomenon inside the fan, and the purpose of the 'high-efficiency and low-noise centrifugal fan, and at the same time providing an air fluid machine using a fan or the like of the centrifugal fan. That is, it provides a technique capable of suppressing the separation of the inside of the fan -6 - 201014983 in a wide operating range, achieving high efficiency and low noise. [Means for Solving the Problems] In order to achieve the above object, according to the present invention, first, an annular guard having a suction port formation and a main board disposed opposite to the shroud, and the shroud and the main board are provided. A plurality of blades disposed in the circumferential direction, the centrifugal fan that can be boosted in the radial direction by the air sucked from the axial direction is provided with a concave shape, and a shape of the leading edge of the blade is substantially concave at a substantially central position in the axial direction, and A centrifugal fan having a convex portion on each of the main plate and the shroud side. Further, in the centrifugal fan according to the present invention, it is preferable that the blade is forward in a direction in which the leading edge of the shroud side is located further than a leading edge of the main plate side, and The blade is formed such that the blade mounting angle of the blade contacting the main plate position has two reverse bend points as the radial position increases, and the leaf mounting angle of the blade contacting the shield position has one reverse bend point. good. Further, it is preferable that the vane has a shape in which the trailing edge is formed to have a convex shape and a concave shape in the rotational direction. Further, according to the present invention, it is possible to provide a flow path in the casing, and to provide a rotary drive means in a part of the frame, and to mount the centrifugal fan in the rotary drive means, thereby performing Air blower for air discharge and supply. [Effect of the Invention] According to the centrifugal fan of the present invention described above and the air-supply machine of the 201014983 using the centrifugal fan, it is possible to achieve an excellent effect of suppressing the separation phenomenon inside the fan in a wide operating range. For a fixed air volume (design point), it is also possible to satisfy low noise and high efficiency for any running air volume required by the user, and therefore, it is possible to provide a method of suppressing separation inside the fan even in a wide air volume operating range. Moreover, the centrifugal fan having high efficiency and low noise can simultaneously provide an air fluid machine such as a blower using the centrifugal fan. [Embodiment] BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. <Embodiment 1> First, an example of the centrifugal fan according to the first embodiment of the present invention and an air fluid machine using the centrifugal fan will be described in detail with reference to Figs. 1 to 5 of the fan filter unit. Fig. 1 is a perspective view showing a centrifugal fan 17 having a blade according to the present invention, wherein Fig. 2(a) is a front view thereof, and Fig. 2(b) is a side view thereof. In addition, Fig. 3 is a view showing the blade mounting of the contact surface of the blade 3 and the shroud for the configuration of the centrifugal fan 17 according to the present invention (see 3d in Fig. 4) and its contact surface with the main plate (see 3c in Fig. 4). Angle distribution chart. 4 is a side view of the blade 3 of the centrifugal fan 17 of the first embodiment, and FIG. 5 is a schematic view showing a fluid machine including the centrifugal fan 17 of the above -8-201014983 as an embodiment. A cross-sectional view of the fan filter unit 13. First, the centrifugal fan 17 according to the present invention has a disk-shaped main plate 1 as shown in Fig. 1 or Fig. 2(a) and Fig. 2(b), and a facing position of the main plate 1. The flat plate material is formed in an annular shape, and the center portion thereof has the shroud 2 of the suction port 4. Then, between the main plate 1 and the shroud 2, a plurality of pieces are arranged in a circumferential direction thereof at regular intervals. (5 pieces in this example) The blade 3 is formed. In addition, the blade 3 is formed, for example, by using a material of a metal plate. The pressure surface of the blade is a flat surface or a curved surface having a smooth surface. Further, the blades 3 are mounted by a fixed structure (e.g., including a mosaic structure or a riveted joint) respectively disposed between the main plate and the shroud 2. Further, the leading edge 3a of the vane 3 is in contact with the main plate 1 as compared with the contact portion 5a of the shroud 2 on the inner diameter side of the suction port as shown in Figs. 1 and 2(a). The portion 5b is a forward position in the rotational direction, that is, inclined forward. On the other hand, the trailing edge 3b of the blade 3 is rotated in the contact portion 5c with the shield 2 as shown in Figs. 1 and 2(a) as compared with the contact portion 5d of the main plate 1. The position in front of the direction. Further, the trailing edge 3b of the vane 3 is formed to extend in the rotational direction at approximately 丨/3 position of the blade exit height "Z". In addition, in this example, the fan outlet width ratio Z/D of the blade outlet height "Z" divided by the fan outer diameter "〇" is 〇.丨8, that is, the form of the centrifugal fan, in order to reduce the mounting of 201014983 The fan filter unit height of the fan uses a smaller fan outlet width ratio. Further, in the second drawing (a), an orthogonal line 7 is formed which is a connecting line 6 to the arbitrary position of the blade 3 and the central axis, and the angle formed by the orthogonal line 7 and the tangent 8 outside the blade 3 is When the blade mounting angle is "/3", as shown in Fig. 3, the blade 3 mounting angle of the inner diameter of the main plate (i.e., the inner diameter side of the suction port 4 on the main plate 1) is set to be smaller than the minimum inner diameter of the shroud. The installation angle is still large. Then, the mounting angle "泠" of the mounting surface @ 3c of the blade 3 contacting the main board 1 is as shown by the solid curve in Fig. 3, and gradually increases as the outer diameter (radius R increases). The blade exit angle (indicated by a broken line in the figure, for example, 50°) is substantially the same angle, and then the point is the inner diameter side reverse bend point 9a, and is lowered to a smaller angle than the blade angle of the inner diameter of the main plate. Reach the outer diameter side reverse bend point 9b. Then, when the outer diameter side inflection point 9b is exceeded, the mounting angle "0" of the mounting surface 3c of the blade 3 contacting the main plate 1 is gradually increased by the angle toward the outer diameter (the radius R is increased). That is, the mounting angle distribution of the mounting surface 3c of the blade piece 3 contacting the main plate 1 is set so as to have two inflection points 9a, 9b toward the outer diameter. Secondly, the mounting angle of the mounting surface 3d of the blade 3 contacting the shroud 2 is as shown by the dashed curve in FIG. 3, and gradually increases the angle from the minimum inner diameter of the shroud toward the outer diameter, so as to face the reverse corner of the shroud. 10, then, gradually increases toward the blade exit angle (increasing with the radius R) at a ratio smaller than the mounting angle of the mounting surface 3c of the blade 3 contacting the main plate 1. That is, the mounting angle distribution of the mounting surface 3d of the blade 3 contacting the shroud 2 is -10-201014983, and is set to have one inflection point 10 toward the outer diameter. Further, as is clear from Fig. 3, in the present embodiment, the shroud turning point 10 of the attachment angle "cold" is reached, and the arrival of the outer diameter side inversion point 9b on the side of the main plate 1 is substantially The same diameter is obtained, and more specifically, the fan outer diameter D is set to a position which can be approximately 0.8 5D. Further, the outer diameter side inflection point 9b on the main plate 1 side is set to be smaller than the mounting angle of the shroud turning point 1〇 by the blade attachment angle "point", so that the load on the main board side can be made small. Thereby the flow inside the fan is made equal. Further, the front edge shape 3a of the blade 3 has a concave shape at a substantially central position (H/2) of the blade height Η as shown in Fig. 4 of the attachment, and 'from the concave shape portion toward the main plate 1 side and The shroud 2 side has a convex shape. That is, according to the front edge shape 3a of the blade 3, it is formed so as to face the shield 2 from the main plate 1 (that is, toward the height direction), and once the radius is changed [refer to the figure 6 of the second (a) diagram] Small, then, at the height of the blade, the height of the half becomes 'then' again, the radius of the blade becomes smaller, and then the radius increases to the shape of the shield, in other words, the leading edge shape 3a of the blade 3 has a Greek-like character The shape of "ε". Further, the leading edge shape 3a of the blade 3 is as shown in Fig. 4, and the angle at which the convex portion forming portion of the main plate 1 side rises from the main plate 1 is set to be formed with the convex portion on the side of the shroud 2 The angle at which the portion is lowered toward the side of the shroud is substantially the same. As an example, in the present embodiment, the horizontal plane parallel to the surface on which the suction port is formed is substantially 45. Angle. According to the configuration of the centrifugal fan 17 described above, the leading edge shape 3a of the vane 3 is located on the side of the shroud 2 on the side of the main plate 1 with respect to the air volume point set at the design time -11 - 201014983. The position is also located forward in the direction of rotation, that is, by tilting forward, it is possible to appropriately respond to the velocity distribution of the suction flow, whereby the flow can be prevented from being separated on the shroud side. In addition to the above, as described above, the angle of attachment of the blade 3 to the blade 3 (that is, the mounting angle of the mounting surface 3c, 3d on the upper main plate 1 side and the shroud 2 side) is referred to. Fig. 3), the counter-fee point (inner diameter side back bend point 9a, outer diameter side back bend point 9b, guard reverse bend point 10, etc.) can be used to increase the workload of the front half of the blade 3 and the latter half of the work. Also, the amount of change in the speed inside the blade 3 can be made the same, whereby the separation phenomenon generated inside the blade can be suppressed. In addition, in particular, a wind volume point which is small in air volume which is not considered at the time of design is also provided in the shield portion which is provided at a substantially central position in the height direction of the leading edge 3a of the blade 3 and is respectively provided in the shield The convex portion on the side of the 2 sides and the main plate 1 causes the large-scale separation vortex generated by the previous centrifugal fan at its leading edge to reduce the scale to the small-scale separation vortex, while the separation vortex is distributed on the main plate 1 side and the shield 2 by G On the side, it is also possible to suppress the reduction in the area of the blade inlet due to the vortex formation being shielded. That is, according to the above effects obtained by the above configuration, it is possible to provide a centrifugal fan capable of achieving high efficiency and low noise, not only for the wind volume of the design, but particularly for a wide air volume range including the low air volume region. Further, according to the above configuration, an air flow path is formed between the main plate 1 and the shroud 2 and the plurality of blades 3, and the configuration is operated by a predetermined rotation -12-201014983. The centrifugal fan 17' can be pushed out from the blade 3 thereof. The air flowing into the suction port 4 can thereby obtain the specified treatment air volume. Next, Fig. 5 of the attachment is a fan filter unit showing an example of an air fluid machine using the above centrifugal fan. Further, the fan filter unit 13 is a device that pressurizes air through the filter 15 by the centrifugal fan 17, thereby removing dust in the air or organic gas such as boron or phosphorus from the filter 15. φ The fan filter unit 13 is also clearly shown in the drawing. Basically, it is composed of a body casing 14 and a filter 15 for air cleaning. Then, the body casing 14 is provided with a motor base for fixing the motor 16. 18. The centrifugal fan 17 is mounted on the rotating shaft of the motor to be rotationally driven. Further, the main body casing 14 is attached with a ring 19' for guiding the centrifugal fan 17, and a bottom plate 20 for rectifying the flow of air sent from the centrifugal fan. That is, according to the fan filter unit shown in Fig. 5, the air 21 来自 from the atmosphere or the space from which the dust in the atmosphere is not removed can be sucked into the interior through the centrifugal fan 17 and then The flow of air ejected by the centrifugal fan 17 becomes the same in the flow path formed by the motor base 20 and the inner wall of the body casing 14 'plus' allows the air to collide with the side wall in the body casing 14 to be bent. 'Blowing out into the space to be cleaned by air. Next, according to Fig. 6 of the attached 'test results obtained by using the fan filter unit of the centrifugal fan 17 of the present embodiment described above', for example, the above 11th and 12th drawings The previous centrifugal fan shown is compared and disclosed below. In addition, in the sixth figure, 'the air volume is the horizontal axis', the wind-13-201014983 fan static pressure [Fig. 6(a)], fan static pressure efficiency [Fig. 6(b)] 'noise level [Test results of Figure 6 (c)]. As shown in the sixth (a) to (c) diagrams, when the centrifugal fan 17 according to the above-described embodiment is known, the static pressure of the wind volume at the time of design is not changed as compared with the prior art, but The static pressure efficiency is increased, and in addition, the noise is almost the same. On the other hand, it is also known that the static pressure is increased and the static pressure efficiency is improved in a region where the air volume at the air volume point is smaller than the design time. In addition, for the noise, it is known that the _ noise can be greatly reduced in a region where the air volume at the air volume point is smaller than the design time. That is, from the results shown in the sixth (a) to (c), it is understood that, according to the present embodiment, it is possible to realize the centrifugal fan not only for the wind volume point at the time of design but also for the wide flow region including the low wind region. High efficiency and low noise. Further, with respect to the centrifugal fan 17 of the present embodiment described above, in order to check the efficiency of designing the air volume point, an improvement effect is obtained, and the comparison of the blade lifts of the number analysis is shown in Fig. 7. In addition, this Fig. 7 is a result obtained by integrating the blade-related lift (L) with the same radius according to the numerical analysis result of the simulation test state, and according to the figure, the workload of the blade can be seen. That is, it is known from Fig. 7 that the present embodiment has a small radius but an increased workload compared to the prior art. Further, it is also known that the blade lift (L), which is the same as the previous product, is reduced to the same extent as the previous product, from the substantially central portion of the radius toward the outer diameter. However, in the outer diameter, the workload is increased. The reason for this is the blade mounting angle on the main board side, so that as long as the blade mounting angle is changed, the workload of the blade can be increased to increase the efficiency. Next, with respect to the centrifugal fan 17 of the present embodiment described above, in particular, -14-201014983, for the structure capable of reducing noise in a low air volume region, that is, for the influence of the shape of the leading edge 3A of the blade 3 on the flow field, use Figure 8 is explained. In the eighth (a) diagram, a trajectory pattern diagram of the flow and the vortex near the leading edge 3a of the blade 3 of the non-designed point of the air volume of the present embodiment is shown, and in order to compare, the figure is shown in Fig. 8(b) The trajectory of the flow and vortex of the previous product. Further, the pattern diagrams of the eighth (a) and eighth (b) diagrams are pattern φ maps based on the results of the numerical analysis after the simulation test state, and the separation vortex 11a generated from the leading edge 3a of the blade 3 The center of the flow is indicated by a broken line, and the flow 12 around it is indicated by a solid line with an arrow symbol. According to the figures, it is known that the front product [Fig. 8(b)] is the vortex 11a which is separated from the front edge 3a by the shroud 2 side, and the flow 12 around the periphery is made larger, and the blade 3 is blocked near the suction port. Negative pressure side. On the other hand, it is known that the present embodiment [Fig. 8(a)] is formed from the main plate 1 toward the shield 2, i.e., once in the height direction, the radius [refer to the figure number 6 of the second (a) figure] Small, then, when the blade height becomes half larger, then the radius thereof becomes smaller a little, and then the radius to the shield is increased to the shape of the leading edge shape 3a of the above-mentioned blade 3, that is, the blade 3 according to the "e" shape. In the shape of the leading edge 3a, it is known that the separation vortex 11 generated from the leading edge shape 3a of the blade 3 is two which form the shroud side separation vortex 1 1 a and the main plate side separation vortex lib. Further, it is also known that the peripheral flow 12 of the separation vortex generated by the convex portion of the leading edge 3a of the blade 3 is smaller than the previous product, so that the blocking area on the negative pressure side of the blade is relaxed, whereby the flow on the negative pressure side can be controlled. . Based on the above, according to the first embodiment, for the designed air volume point -15-201014983, the suction port 4 of the blade 3 has the front edge 5a of the shroud in front of the front edge 5b of the main plate in the direction of rotation, thereby enabling Corresponding to the velocity distribution of the suction flow, this makes it difficult for the flow to separate on the shroud side. In addition, by adopting the reverse bending point of the blade mounting angle, it is possible to increase the workload of the front half of the blade and the workload of the latter half, and at the same time, the speed variation inside the blade can be made the same, thereby suppressing the internal generation of the blade. Separation phenomenon. In addition, in particular, for a non-design point having a small air volume, it is also possible to transmit a first-front centrifugal fan at its leading edge through a function of a convex portion formed on the side of the shield 2 of the leading edge 3a of the blade 3 and the side of the main plate 1. The large-scale separation vortex generated is distributed on the main board side and the shroud side, and can be a small-scale separation vortex. Namely, the scale of the separation vortex generated at the leading edge of the centrifugal fan is reduced, whereby the decrease in the suction area immediately after the inlet of the blade 3 can be suppressed. Then, according to the above action, not only the design point but also the high efficiency and low noise of the centrifugal fan can be achieved even in the low air volume region. In addition, when there is an obstacle or the like in the vicinity of the fan outlet, the noise increases due to interference with the flow from the blade, but the trailing edge @ of the blade is inclined in the circumferential direction, so the flow with the obstacle is involved. A temporal deviation is generated and the high-frequency sound of the blade can be suppressed, thereby contributing to the improvement of the timbre of the noise. Further, in particular, the fan filter unit 13 which is an example of an air fluid machine using the above-described centrifugal fan usually has a continuous operation for several years, so that dust adheres to the filter 15, so that the pressure loss of the filter increases year by year. That is, based on this, the fan filter unit will operate at a lower air volume than the design point. However, according to the centrifugal fan using the above-described present invention, the noise is increased by 16 - 201014983 or the efficiency is reduced less than that of the prior fan, and the efficiency can be maintained over a wide operating range, and, in addition, Contributed to the power saving. <Embodiment 2> Next, a second embodiment of another embodiment of the present invention will be described with reference to Fig. 9. Further, Fig. 9 is a side view showing, in particular, a centrifugal fan 17 having a blade according to the present invention. As is clear from the figure, the centrifugal fan 17 of the present embodiment is provided with the main board 1 and the position of the main board 1 at the same time as the first board or the second figure, and is formed of a flat material. A part of the so-called shroud 2 having the suction port 4, and between the main plate 1 and the shroud 2, is added by a plurality of blades (5 pieces in this example) provided at regular intervals in the circumferential direction. Composition. Further, the blade 3 is formed, for example, using a material of a metal flat plate, and the pressure surface of the blade is formed as a flat surface or a smooth concave surface, and then, respectively, is provided on the β main board 1 and the shield. The fixed structure between 2 (for example: including mosaic or riveted joint) is installed. Further, the suction port diameter 4 of the vane 3 is forward of the shroud leading edge 5a in front of the main plate leading edge 5b in the rotational direction. Further, as shown in Fig. 3, the leading edge shape 3a of the blade has a concave shape at a substantially central position (H/2) of the blade height ,, and the main plate and the shroud side have a convex shape. That is, its shape is formed from the main board toward the shroud, in the height direction, once the radius is first reduced, and then reaches half of the blade height, the radius becomes larger, and then the radius becomes smaller again, and then the radius increases -17-201014983 to reach the shroud The shape of the leading edge is a "ε" shape similar to the Greek character. Further, in the second embodiment, in particular, the shroud side of the trailing edge 3b of the vane 3 is provided with a convex portion and a concave portion in the rotational direction from the main plate 1 side to the shroud 2 side as shown in Fig. 9. . That is, it is formed in a substantially "S" shape which is formed at a substantially 1/2 of the blade exit height Z and has a reverse bend point, which is convex toward the main plate side in the rotation direction and which is recessed on the shroud side. The reason for this is to ensure that the amount of work on the side of the main board 1 is the same as that of Fig. 2 described above, and is formed in a shape in which the shape is convex toward the direction of rotation. Further, as shown in the above-mentioned Fig. 8, the concave shape on the side of the shroud 2 is to further suppress the growth of the separation vortex on the side of the shroud 2 by the leading edge 3a of the vane 3, thereby making the wing of the shroud 2 side The area becomes smaller. The above-described configuration of the vane 3, as described above, for the designed air volume point, the leading edge 5a of the vane side 3 of the inner diameter of the suction port 4 is located further in front of the rotation direction than the leading edge 5b of the main plate side [ Referring to Fig. 1 and Fig. 2(a), it is formed so as to be inclined forward, so that the velocity distribution of the suction flow _ can be made to make the flow difficult to separate on the shroud side. Further, for the non-design point where the air volume is small, the concave shape 3 a formed at the substantially central position in the height direction, and the convex portions on the shield side and the main board side of the leading edge (that is, the "ε" shape) The large-scale separation vortex generated by the front edge of the centrifugal fan can be reduced to a small-scale separation vortex and distributed on the main board side and the shroud side, so that the vortex formation can be suppressed from being shielded so that the area of the blade is reduced. Further, the trailing edge shape 3b of the blade 3 is formed into a convex shape and a concave shape (i.e., an "S" shape) in the rotational direction, so that -18-201014983 can guide the vortex and control the vortex to enter the orbit after the blade 3, Therefore, it is possible to suppress the separation phenomenon occurring on the suction side of the blade 3. According to the above functions, the high efficiency and low noise of the centrifugal fan can be achieved not only for the design point, but also in the low air volume region. According to the above configuration, an air flow path is formed between the main plate 1 and the shroud 2 and the plurality of blades 3, and then the centrifugal fan having the configuration is operated at a predetermined rotation, and the vanes of the vanes 3 can be pushed out from the suction port 4 The inflowing helium air obtains the specified treatment air volume. The comparison of the test results of the second embodiment with the previous products is illustrated by using the attached figures 10(a) to 10(C). In addition, in these figures, the air volume is shown as the horizontal axis, and on the other hand, the vertical axis is the fan static pressure [Fig. 10(a)], the fan static pressure efficiency [Fig. 10(b)], and the noise level. The test results of [Number 10(c)]. It can also be clearly seen from the results of the tests that the centrifugal pressure of the design point according to the second embodiment described above does not change the static pressure at the design point, but the static pressure efficiency increases, and the noise is the same. . In addition, it is also known that the static pressure is increased and the static pressure efficiency is improved in a region where the air volume is smaller than the design air volume. In addition, for the noise, it is known that even in a region where the air volume is smaller than the design time, it is possible to reduce the noise as the design point. That is, from the results shown in Figs. 10(a) to (c), it is understood that according to the present embodiment, it is possible to realize high efficiency and low noise of the centrifugal fan not only for the design point but also for the low air volume region. Chemical. In addition, when an obstacle or the like is located near the fan outlet, the noise increases due to interference with the blade discharge flow, but since the trailing edge 3b of the blade 3 is inclined in the direction of the circumference • 19 - 201014983 (ie, the word "S") Since the shape interferes with the flow of the obstacle, temporal deviation can be suppressed, and the high-frequency sound of the blade can be suppressed, thereby contributing to the improvement of the timbre of the noise. In addition, since the fan filter unit is continuously operated for several years, dust adheres to the filter, and therefore the pressure loss of the filter increases year by year. Therefore, the fan filter unit can be operated in a state where the air volume is lower than the design point, but by using the centrifugal fan of the present invention, it is possible to reduce the increase in noise or the decrease in efficiency more than the previous fan' and to operate in a wide range. The range can maintain high efficiency, so it can contribute to power saving. In the above description, the centrifugal fan mounted on the fan filter unit has been described as an example. However, even if it is used in other equipment such as an air conditioner, it is possible to maintain high efficiency over a wide operating range and contribute to power saving. . BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing the entire structure of a centrifugal fan having a blade according to the present invention (implementing φ Example 1). Fig. 2 is a front view and a side view of the centrifugal fan (Example i). Fig. 3 is a view showing a blade mounting angle distribution of the shield and the main plate contact surface of the centrifugal fan (Example 1). Fig. 4 is an enlarged side elevational view of the centrifugal fan (Example 1). Fig. 5 is a cross-sectional view showing a fan unit -20 - 201014983 equipped with the above-described centrifugal fan (Example 1). Fig. 6 is a view showing a comparison of the air volume-static pressure characteristic, the air volume-efficiency characteristic, the air volume-noise characteristic and the previous centrifugal fan of the centrifugal fan (Embodiment 1) of the present invention. Fig. 7 is a view showing a comparison between the results of the analysis of the lift characteristics of the centrifugal fan of the present invention described above and the prior centrifugal fan. Fig. 8 is a view showing a comparison of the vortex caused by the shape of the leading edge of the centrifugal fan according to the present invention at the φ non-design point air volume and the scale of the centrifugal fan. Fig. 9 is a side view showing the centrifugal fan (Embodiment 2) of the present invention. Fig. 1 is a view showing a comparison between the air volume-static characteristic, the air volume-efficiency characteristic, the air volume-noise characteristic of the centrifugal fan (Example 2) and the prior centrifugal fan. Figure 11 is a front elevational view showing a prior centrifugal fan. ® Figure 12 is a side view showing a prior centrifugal fan. [Main component symbol description] 1 : Main board 2 : Shield 3 : Blade 3a : Leading edge 3b : Rear edge 3c : Contact of the blade to the main plate surface - 21 - 201014983 3d : Contact contact surface of the blade 4 : Intake port 5 : Inhalation Blade position 6 of the mouth: connecting line of the blade position and the central axis 7: orthogonal line 8 of the connecting line 6: tangent of the blade shape 9: reverse bending point of the blade mounting angle 9a: inner diameter side reverse bending point @ 9b : outside Diameter side reverse bend point 1 0 : Shield reverse bend point 11 : Separation vortex generated at the leading edge 1 1 a : Shield side separation vortex lib : Hub side separation vortex 1 2 : Separation vortex peripheral flow 13 : Fan filter unit 14: Body shell G 1 5 : Filter 1 6 : Motor 1 7 : Centrifugal fan 1 8 : Motor base 1 9 : Ring 20 : Base plate 22-