JP4321690B2

JP4321690B2 - Axial blower

Info

Publication number: JP4321690B2
Application number: JP26737099A
Authority: JP
Inventors: 満義石嶋; 知史清水
Original assignee: Toshiba Carrier Corp
Current assignee: Toshiba Carrier Corp
Priority date: 1999-09-21
Filing date: 1999-09-21
Publication date: 2009-08-26
Anticipated expiration: 2019-09-21
Also published as: JP2001090692A

Description

【０００１】
【発明の属する技術分野】
本発明は、例えば空気調和機の室外ファンや換気装置等に好適な軸流送風機に係り、特に、翼負圧面上の流れの剥離を抑制して送風性能の向上と送風音の低減とを共に図った軸流送風機に関する。
【０００２】
【従来の技術】
図１３は従来の軸流送風機１の翼負圧面側から見たときの正面図、図１４は、その軸流送風機１の翼１枚分を図示して他の翼を省略した一部切欠正面図である。この軸流送風機１は、図示しない回転軸が中心部Ｏに固定される円筒状のボス部２の外周側面に、複数の翼３，３…を周方向に所定のピッチを置いて一体または一体的に形成している。各翼３は、図中矢印で示す送風機回転方向（周方向）に対して空気流の上流側端部をなす凹弧状の前縁部３ａと、空気流の下流側端部をなす後縁部３ｂと、凸弧状の外周端部３ｃと、図１５でも示す流体吸込側の負圧面３ｄと、その裏面側の正圧面３ｅとを有する。
【０００３】
そして、各翼３の負圧面３ｄ側の前縁部３ａの厚さを後縁部よりも厚い流線形の厚肉部３ｆに形成すると共に、この流線形厚肉部３ｆの前縁部３ａ上に、正面形状がほぼ矩形の複数の流線形リブ４を前縁部３ａの輪郭線（外形線）に沿って送風機半径方向に所定間隔を置いて列状に配設している。
【０００４】
図１５は図１２で示すようにボス部２の中心部に固定される図示しない回転軸の軸心Ｏから半径方向に任意の距離ｒ離れた部分における周方向の翼断面を示している。
【０００５】
この図１５に示すように各翼３の負圧面３ｄ側の前縁部３ａには、流線形厚肉部３ｆが形成され、しかもその流線形厚肉部３ｆ上には複数の流線形リブ４を配設しているので、この翼負圧面３ｄ側前縁部３ａから流入した空気流れＵが流線形リブ４を通風した後に縦渦列Ｕｚになる。このために、負圧面３ｄから空気流れが剥離するのを抑制することができるので、後縁部３ｂの後方（下流）に発生する後流渦ｆｕの幅を縮小して送風音を低減させることができる。
【０００６】
【発明が解決しようとする課題】
しかしながら、このような従来の軸流送風機１では、流線形リブ４が１列しか配列されていないので、送風音低減効果が必ずしも十分ではないという課題がある。
【０００７】
本発明はこのような事情を考慮してなされたもので、その目的は、翼負圧面で発生する流れの剥離をさらに低減して送風音をさらに低減することができる安価で成形性の良好な軸流送風機を提供することにある。
【０００８】
【課題を解決するための手段】
請求項１に係る発明は、回転軸が固定されるボス部の外周に、複数の翼を配設した軸流送風機において、上記各翼の負圧面側前縁部に、その前縁から翼後縁に向けて滑かに連なる流線形リブを、上記前縁部の輪郭線に沿ってボス部と外周端部間に所定の間隔を置いて列状に複数配設し、この流線形リブ列を送風機周方向に所定の間隔を置いて複数列設け、翼前縁側の外側流線形リブ列よりも送風機周方向内側に設けた内側流線形リブ列の各流線形リブの流入空気の通風方向を案内する通風側面を、回転軸中心Ｏと、翼外周と翼後縁との交点Ｑと、を結ぶ線分ＯＱに対して各々の所定角度でそれぞれ傾斜させ、これらの各傾斜角を翼外周からボス部側の流線形リブに行くに従って大きくすることを特徴とする軸流送風機である。
【０００９】
請求項２に係る発明は、内側流線形リブ列の各流線形リブは、その流入空気の通風方向を案内する通風側面の角度を、上記外側流線形リブ列の通風側面の角度に対して１２°〜１８°の範囲で傾斜させていることを特徴とする請求項１記載の軸流送風機である。
【００１０】
請求項３に係る発明は、内側流線形リブ列の各流線形リブの送風機周方向に沿う長さＬ２を、外側流線形リブ列の各流線形リブの送風機周方向に沿う長さＬ１に対し、ほぼ０．８Ｌ１の長さに形成していることを特徴とする請求項１または２に記載の軸流送風機である。
【００１１】
請求項４に係る発明は、内側流線形リブ列は、その流線形リブを、外側流線形リブ列の流線形リブ同士の間隙に対応する位置に配設していることを特徴とする請求項１〜３のいずれか１項に記載の軸流送風機である。
【００１２】
請求項５に係る発明は、内側流線形リブ列の各流線形リブは、その送風機周方向に沿う断面の外面が円弧面をなし、その円弧外面の翼前縁側一部の円弧曲面の半径ｒｃの方が、その反対側他部の円弧曲面の半径ｒｄよりも大きくなるように一体に形成されていることを特徴とする請求項１〜４のいずれか１項に記載の軸流送風機である。
【００１５】
請求項５に係る発明は、内側流線形リブ列の各流線形リブは、その送風機周方向に沿う断面の外面が円弧面をなし、その円弧外面の翼前縁側一部の円弧曲面の半径ｒｃの方が、その反対側他部の円弧曲面の半径ｒｄよりも大きくなるように一体に形成されていることを特徴とする請求項１〜４のいずれか１項に記載の軸流送風機である。
【００１７】
これらの各発明によれば、軸流送風機の回転により各翼がボス部の軸心周りに回転すると、各翼の負圧面側の前縁部に、その外方から流入した空気流れが複数列の流線形リブをそれぞれ通過して縦渦列となるので、翼負圧面上で層流境界層から乱流境界層に遷移される。この乱流境界層は層流境界層よりも気流の流れの剥離が発生しにくいうえに、送風音の原因をなす後流渦の幅を狭くするので、送風音を低減することができる。しかも、上記流線形リブが通風方向に複数列あるので、上記図１３等で示す流線形リブが１列しかない従来例よりも、送風音の原因をなす後流渦の幅をさらに狭くすることができる。このために、送風音をさらに低減することができる。さらに、各流線形リブは各翼に例えば樹脂モールド成型等により簡単に一体成形できるので、成形性が良好であり、製造コストを低減できる。
【００２０】
【発明の実施の形態】
以下、本発明の実施形態を図１〜図１２に基づいて説明する。なお、これらの図中、同一または相当部分には同一符号を付している。
【００２１】
図１は本発明の一実施形態に係る軸流送風機１１を翼負圧面側から見たときの全体構成を示す正面図、図２はその翼１枚分を図示して他の翼を図示省略して示す一部切欠正面図である。これらの図に示すように軸流送風機１１は円筒状のボス部１２の外周側面に、複数の翼１３，１３，１３を例えば周方向等分位置にて一体ないし一体的に取り付けており、例えば樹脂モールド成形等により一体に成形される。
【００２２】
ボス部１２は有底円筒状の本体１２ａの内部中心部に、図示しない駆動モータの回転軸を挿入させて固定するための小円筒状のボス１２ｂと、このボス１２ｂから放射状に延びてボス本体１２ａの内周面に一体に連結するほぼ逆Ｙ字状の連結リブ１２ｃとを一体に連成している。
【００２３】
一方、各翼１３は、空気吸込側の負圧面１３ａと、その裏面の送風側である正圧面１３ｂと、図１，図２中矢印で示す送風機回転方向に対し、各翼１３の空気流の上流側端部をなす凹弧状の前縁部１３ｃと、空気流の下流側端部をなす後縁部１３ｄと、これら前縁部１３ｃと後縁部１３ｄの径方向外端同士を一体に連結してなる凸弧状の外周端部１３ｅとを一体に形成している。
【００２４】
そして、各翼１３は、負圧面１３ａ側の前縁部１３ｃ上に、正面形状がほぼ長方形で前縁部１３ｃの前縁（前端）から後縁部１３ｄ方向に向けて滑かに連なる複数の流線形リブ１４を上記前縁部の輪郭線に沿ってボス１２ｂと外周端部１３ｅ間に所定の間隔を置いて列状に配置することにより外側流線形リブ列１４ａを形成している。さらに、この外側流線形リブ列１４ａよりも送風機周方向後縁部１３ｄ側（つまり翼内面側）へ所定間隔離れた箇所において、複数の流線形リブ１４を上記前縁部の輪郭線に沿ってボス１２ｂと外周端部１３ｅ間に所定の間隔を置いて列状に配設して内側流線形リブ列１４ｂを形成し、これら内，外側流線形リブ列１４ｂ，１４ａを並列に設けている。
【００２５】
そして、図２に示すように内側流線形リブ列１４ｂの各流線形リブ１４は、その空気流れの通風方向を案内する通風側面１４ｂ_１を、その外側近傍の外側流線形リブ列１４ａの各流線形リブ１４の通風側面１４ａ_１に対して角度θで傾斜させており、その角度θとしては例えば１２°〜１８°の範囲に設定されている。
【００２６】
また、図３に示すように内側流線形リブ列１４ｂの各流線形リブ１４の通風側面１４ｂ_１は、送風機回転中心、すなわちボス部１２の中心Ｏと、翼後縁部１３ｄの後縁と翼外周１３ｅとの交点Ｑと、を結ぶ線分ＯＱに対しても、各所定角度α_１，α_２，α_３…α_ｎで傾斜している。しかも、これら傾斜角度α_１〜α_ｎは、翼外周１３ｅに最も近い流線形リブ１４の通風側面１４ｂ_１の角度α_１からボス部１２に最も近い流線形リブ１４の通風側面１４ｂ_１の角度αｎに行くに従って漸次傾斜角度が大きくなり、α_ｎ＝２α_１に設定されている。
【００２７】
図４はこのように構成された軸流送風機１１の翼負圧面１３ａ側の空気流れＵの状態を矢印線で示している。図５は図４で示すようにボス部２の中心から半径方向に所定距離ｒ_１離れた翼１３の任意箇所において送風機周方向に切断したときの翼断面と、その翼断面を流れる空気流れＵの状態を示している。これらの図中、矢印線は空気の流れ方向を示し、矢印線の回転は縦渦列Ｕｚを表している。
【００２８】
これら図４，図５に示すように、上記軸流送風機１１では、その前縁部１３ｃの前縁フィレットから翼負圧面１３ａ上に流入した空気流れＵが外側流線形リブ列１４ａと内側流線形リブ列１４ｂとをそれぞれ通過して、縦渦列Ｕｚとなり、翼負圧面１３ａ上を層流境界層から乱流境界層に遷移させる。これにより、送風音の原因をなす後流渦ｆｚの幅を狭くして送風音を低減させることができる。
【００２９】
しかも、この軸流送風機１１によれば、流線形リブ１４のリブ列が内，外２列１４ｂ，１４ａあるので、この内，外流線形リブ列１４ｂ，１４ａを空気流れＵが通過することにより翼負圧面１３ａ上で２重に縦渦列Ｕｚを発生させることができる。このために、流線形リブ１４が１列しかない例えば図１３で示す従来の軸流送風機１よりも縦渦列Ｕｚの発生量を増大させることができるので、送風音の原因である後流渦ｆｚの幅をさらに狭くすることができ、その分、送風量をさらに低減することができる。なお、上記流線形リブ１４ｂは３列以上設けてもよい。
【００３０】
そして、図６に示すように上記内側流線形リブ列１４ｂは、その各流線形リブ１４の送風機周方向に沿う長手方向の長さＬ_２を、外側流線形リブ列１４ａの各流線形リブ１４の送風機周方向に沿う長手方向の長さＬ_１よりも短かく形成し、例えば０．８Ｌ_１に形成している。また、内側流線形リブ列１４ｂの各流線形リブ１４の径方向の間隔Ｗをほぼ等間隔に設定している。
【００３１】
さらに、図７に示すように内側流線形リブ列１４ｂの各流線形リブ１４を、外側流線形リブ列１４ａの送風機半径方向で隣り合う流線形リブ１４同士の間隙に対応する位置に配設している。
【００３２】
さらにまた、図８に示すように、外側流線形リブ列１４ａの各流線形リブ１４の前縁（図８では右端）同士を結ぶ仮想の円弧曲線１５ａの中心をＰ、その半径をｒａとしたときに、その中心Ｐと同心でかつ半径ｒａよりも大径の半径ｒｂの仮想の円弧曲線１５ｂ上に、内側流線形リブ列１４ｂの各流線形リブ１４の前縁が位置するように配置している。
【００３３】
また、図９に示すように外側流線形リブ列１４ａにおける各流線形リブ１４の送風機半径方向の幅Ｗａと、内側流線形リブ列１４ｂにおける各流線形リブ１４の送風機半径方向の幅Ｗｂとをほぼ同一幅に形成している。
【００３４】
図１０は内側流線形リブ列１４ｂの各流線形リブ１４を送風機周方向に沿って切断したときの円弧状断面１４ｃを示しており、この円弧状断面１４ｃは、その翼前縁部１３ｃ側の一部である前半部１４ｃ１の曲率半径をｒｃ、その他部である後半部１４ｃ２の曲率半径をｒｄとしたときにｒｃ＞ｒｄが成立するように形成されている。
【００３５】
ところで、図１１に示すように各翼１３の前縁部１３ｃの送風機半径方向に沿う翼断面の厚さｈ_０はボス部１２側Ｚａから翼外周１３ｅ側Ｚｂへ行くに従って漸次薄くなるように除変されている。
【００３６】
一方、図１２に示すように各流線形リブ１４の高さは、ボス部１２側Ｙａから翼外周１３ｅ側Ｙｂへ行くに従って漸次高くなるように徐変されており、翼外周１３ｅに最も近い流線形リブの高さｈ_１と、ボス部１２に最も近い流線形リブ１４の高さｈ_２とは、ｈ_１＝２ｈ_２となるように形成されている。すなわち、各流線形リブ１４の高さが増して行く方向と、翼負圧面側前縁部１３ｃの厚さを増して行く方向とが正反対であるので、この前縁部１３ｃの厚さｈ_０を含めた断面厚さｈ_ｔがいずれの箇所でもほぼ等しくなる。このため、軸流送風機１１の樹脂成形時による一体成形の冷却時間の短縮および肉ひけ等を防止ないし低減することができる。
【００３７】
また、軸流送風機１１は以上のように内側流線形リブ列１４ｂの各流線形リブ１４の長手方向の長さＬ_２、設置間隔Ｗ、設置位置、前縁の位置、幅Ｗｂ、円弧外面の曲率等をそれぞれ設定したので、縦渦列を翼負圧面１３ａ上に安定して発生させることができ、そのために送風音をさらに低減することができる。
【００３８】
【発明の効果】
以上説明したように、本発明は各翼の負圧面側前縁部に、その前縁端から滑らかに連なる流線形リブを複数列並設しているので、翼負圧面上にて空気流れの縦渦列を発生させ、流れの剥離を抑制することができ、ひいては翼後縁部後方にできる後流渦幅を小さくして送風音を低減することができる。また、各流線形リブが流線形状であるので、軸流送風機を例えば樹脂モールド成形により簡単に一体成形でき、成形性の向上と製造コスト低減とを共に図ることができる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る軸流送風機を翼負圧面側から見たときの全体構成の正面図。
【図２】図１で示す軸流送風機の内側流線形リブ列における各流線形リブの通風側面の傾斜角度を説明するための一部切欠正面図。
【図３】図１で示す軸流送風機の内側流線形リブ列における各流線形リブの傾斜角をそれぞれ変える場合の一部切欠正面図。
【図４】図１等で示す軸流送風機の翼負圧面上の空気流れの状態を示す一部切欠正面図。
【図５】図４で示す軸流送風機の翼を半径ｒ_１にて送風機周方向に沿って切断したときの翼断面図。
【図６】図１等で示す軸流送風機の内側流線形リブ列における各流線形リブの長手方向長さと各リブ同士の配置間隔を示す一部切欠正面図。
【図７】図１等で示す軸流送風機における内側流線形リブ列の各流線形リブを、外側流線形リブ列の各流線形リブ同士の間隙に対応する位置に配置する場合の一部切欠正面図。
【図８】図１等で示す軸流送風機における外側流線形リブ列の各流線形リブの前縁と、内側流線形リブ列の各流線形リブの前縁の位置関係をそれぞれ示す一部切欠正面図。
【図９】図１等で示す軸流送風機における内，外側流線形リブ列の各流線形リブの幅を説明するための一部切欠正面図。
【図１０】図１等で示す各流線形リブの縦断面図。
【図１１】図１等で示す軸流送風機の前縁部の送風機半径方向に沿う断面図。
【図１２】図１等で示すボス部と内側流線形リブ列とを送風機半径方向に沿って切断したときの断面を示す模式図。
【図１３】従来の軸流送風機の負圧面側から見たときの正面図。
【図１４】図１３で示す従来の軸流送風機の翼１枚分を示す一部切欠正面図。
【図１５】図１３で示す軸流送風機の回転中心から任意の半径で翼を周方向に切断したときの翼断面図。
【符号の説明】
１１軸流送風機
１２ボス部
１３翼
１３ａ翼の負圧面
１３ｃ翼の前縁部
１３ｄ翼の後縁部
１３ｅ翼の外周端部
１４流線形リブ
１４ａ外側流線形リブ列
１４ｂ内側流線形リブ列
１５ａ，１５ｂ外，内側円弧曲線[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an axial blower suitable for, for example, an outdoor fan or a ventilator of an air conditioner, and in particular, to improve the blowing performance and reduce the blowing sound by suppressing the separation of the flow on the blade suction surface. It relates to the axial flow blower.
[0002]
[Prior art]
FIG. 13 is a front view when viewed from the blade suction surface side of a conventional axial flow fan 1, and FIG. 14 is a partially cutaway front view illustrating one blade of the axial flow fan 1 and omitting other blades. FIG. This axial blower 1 is integrated or integrated with a plurality of blades 3, 3... At a predetermined pitch in the circumferential direction on the outer peripheral side surface of a cylindrical boss portion 2 whose rotating shaft (not shown) is fixed to the central portion O. Is formed. Each blade 3 has a concave arc-shaped front edge 3a that forms an upstream end of the air flow with respect to the fan rotation direction (circumferential direction) indicated by an arrow in the figure, and a trailing edge that forms a downstream end of the air flow. 3b, a convex arc-shaped outer peripheral end 3c, a negative pressure surface 3d on the fluid suction side also shown in FIG. 15, and a positive pressure surface 3e on the back side thereof.
[0003]
Then, the thickness of the leading edge portion 3a on the suction surface 3d side of each blade 3 is formed into a streamlined thick portion 3f thicker than the trailing edge portion, and on the leading edge portion 3a of the streamline thick portion 3f. In addition, a plurality of streamlined ribs 4 having a substantially rectangular front shape are arranged in a row at predetermined intervals in the radial direction of the blower along the outline (outline) of the front edge 3a.
[0004]
FIG. 15 shows a blade section in the circumferential direction at a portion that is separated by an arbitrary distance r in the radial direction from the axis O of the rotating shaft (not shown) fixed to the center of the boss 2 as shown in FIG.
[0005]
As shown in FIG. 15, a streamlined thick part 3f is formed on the leading edge 3a on the suction surface 3d side of each blade 3, and a plurality of streamlined ribs 4 are formed on the streamlined thick part 3f. Therefore, after the air flow U flowing in from the blade suction surface 3d side front edge portion 3a passes through the streamlined rib 4, it becomes a longitudinal vortex row Uz. For this reason, it is possible to suppress separation of the air flow from the negative pressure surface 3d. Therefore, the width of the wake vortex fu generated behind (downstream) the rear edge 3b is reduced to reduce the blowing sound. Can do.
[0006]
[Problems to be solved by the invention]
However, in such a conventional axial blower 1, since only one row of streamline ribs 4 is arranged, there is a problem that the effect of reducing the blowing noise is not always sufficient.
[0007]
The present invention has been made in consideration of such circumstances, and its purpose is to reduce the flow separation generated on the blade suction surface and to further reduce the blowing noise at a low cost and good formability. The object is to provide an axial blower.
[0008]
[Means for Solving the Problems]
The invention according to claim 1 is the axial blower in which a plurality of blades are arranged on the outer periphery of the boss portion to which the rotation shaft is fixed. The suction surface side front edge portion of each blade is moved from the front edge to the blade rear. A plurality of streamlined ribs continuously extending toward the edge are arranged in a row at a predetermined interval between the boss part and the outer peripheral end along the contour line of the front edge part. A plurality of rows are provided at predetermined intervals in the blower circumferential direction, and the flow direction of the inflow air of each streamline rib of the inner streamline rib row provided on the inner side in the blower circumferential direction than the outer streamline rib row on the blade leading edge side. The ventilation side to be guided is inclined at each predetermined angle with respect to a line segment OQ connecting the rotation axis center O and the intersection Q between the blade outer periphery and the blade trailing edge. It is an axial flow fan characterized by enlarging as it goes to the streamline rib on the boss part side .
[0009]
In the invention according to claim 2, each streamline rib of the inner streamline rib row has an angle of the ventilation side surface for guiding the ventilation direction of the inflowing air with respect to the angle of the ventilation side surface of the outer streamline rib row. 2. The axial-flow fan according to claim 1, wherein the fan is inclined in a range of from [deg.] To 18 [deg.].
[0010]
In the invention according to claim 3, the length L2 along the blower circumferential direction of each streamline rib of the inner streamline rib row is set to the length L1 along the blower circumferential direction of each streamline rib of the outer streamline rib row. The axial blower according to claim 1 or 2, wherein the axial blower is formed to have a length of approximately 0.8L1.
[0011]
Claim invention according to claim 4, inner flow linear ribs column to its streamlined ribs, characterized in that it is disposed at a position corresponding to the gap of the aerodynamic ribs between the outer flow linear rib columns It is an axial blower of any one of 1-3 .
[0012]
In the invention according to claim 5, each streamlined rib of the inner streamlined rib row has an outer surface of a cross section along the circumferential direction of the blower forming an arc surface, and a radius rc of an arc curved surface at a part of the front edge of the blade on the outer surface of the arc. The axial flow fan according to any one of claims 1 to 4, wherein the one is integrally formed so as to be larger than the radius rd of the arcuate curved surface on the other side of the opposite side. .
[0015]
In the invention according to claim 5 , each streamlined rib of the inner streamlined rib row has an outer surface of a cross section along the circumferential direction of the blower forming an arc surface, and a radius rc of an arc curved surface at a part of the front edge of the blade on the outer surface of the arc. The axial flow fan according to any one of claims 1 to 4, wherein the one is integrally formed so as to be larger than the radius rd of the arcuate curved surface on the other side of the opposite side. .
[0017]
According to each of these inventions, when each blade rotates about the axis of the boss portion by the rotation of the axial blower, a plurality of rows of air flows from the outside flow into the front edge portion on the suction surface side of each blade. Each of the streamlined ribs forms a longitudinal vortex train, so that a transition is made from the laminar boundary layer to the turbulent boundary layer on the blade suction surface. The turbulent boundary layer is less likely to cause separation of the airflow than the laminar boundary layer, and the width of the wake vortex causing the blowing sound is narrowed, so that the blowing sound can be reduced. In addition, since there are a plurality of rows of streamline ribs in the ventilation direction, the width of the wake vortex that causes the blowing sound is made narrower than the conventional example in which there are only one row of streamline ribs shown in FIG. Can do. For this reason, the blowing sound can be further reduced. Furthermore, since each streamline rib can be easily integrally formed with each blade by, for example, resin molding, the moldability is good and the manufacturing cost can be reduced.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. In these drawings, the same or corresponding parts are denoted by the same reference numerals.
[0021]
FIG. 1 is a front view showing an overall configuration of an axial blower 11 according to an embodiment of the present invention when viewed from the blade suction surface side, and FIG. 2 shows one blade and omits other blades. It is a partially cutaway front view shown. As shown in these drawings, the axial blower 11 has a plurality of blades 13, 13, 13 integrally or integrally attached to the outer peripheral side surface of a cylindrical boss portion 12, for example, at circumferentially equal positions. It is integrally formed by resin molding or the like.
[0022]
The boss part 12 has a small cylindrical boss 12b for inserting and fixing a rotating shaft of a drive motor (not shown) in the center of the bottomed cylindrical body 12a, and a boss body extending radially from the boss 12b. A substantially inverted Y-shaped connecting rib 12c that is integrally connected to the inner peripheral surface of 12a is integrally connected.
[0023]
On the other hand, each blade 13 has a negative pressure surface 13a on the air suction side, a positive pressure surface 13b on the back side of the air suction side, and the air flow of each blade 13 with respect to the fan rotation direction indicated by the arrows in FIGS. A concave arc-shaped front edge 13c that forms the upstream end, a rear edge 13d that forms the downstream end of the air flow, and the radially outer ends of the front edge 13c and the rear edge 13d are connected together. A convex arc-shaped outer peripheral end portion 13e is integrally formed.
[0024]
Each blade 13 is formed on the front edge portion 13c on the suction surface 13a side so that the front shape is substantially rectangular and is smoothly connected from the front edge (front end) of the front edge portion 13c toward the rear edge portion 13d. Outer streamlined rib rows 14a are formed by arranging the streamlined ribs 14 in a row at a predetermined interval between the boss 12b and the outer peripheral end 13e along the contour line of the front edge portion . Further, a plurality of streamline ribs 14 are arranged along the contour line of the front edge portion at a predetermined distance from the outer streamline rib row 14a to the rear circumferential edge portion 13d side (that is, the blade inner surface side). The inner streamlined rib rows 14b are formed in a row at a predetermined interval between the boss 12b and the outer peripheral end portion 13e, and the inner and outer streamlined rib rows 14b, 14a are provided in parallel.
[0025]
Each aerodynamic ribs 14 of the inner flow linear ribs column 14b as shown in FIG. 2, the ventilation side 14b ₁ for guiding the airflow direction of the air flow, the flow of the outer flow linear ribs column 14a of the outer vicinity and it is inclined at an angle θ with respect to the ventilation side 14a ₁ of the linear rib 14, as the angle θ is set in a range of for example 12 ° ~ 18 °.
[0026]
Further, the ventilation side 14b ₁ of the inner flow linear ribs columns 14b each aerodynamic ribs 14 as shown in FIG. 3, blower rotational center, i.e. the center O of the boss portion 12, and the trailing edge of the blade trailing edge 13d wings The line segment OQ connecting the intersection point Q with the outer periphery 13e is also inclined at predetermined angles α ₁ , α ₂ , α ₃ ... Α _n . Moreover, the inclined angle alpha ₁ to? _N, the angle of the ventilation side 14b ₁ of the ventilation side 14b ₁ of the angle alpha ₁ closest streamlined rib 14 to the boss 12 from the aerodynamic ribs 14 closest to the outer circumferential blade 13e .alpha.n As the angle goes to, the inclination angle gradually increases, and α _n = 2α ₁ is set.
[0027]
FIG. 4 shows the state of the air flow U on the blade negative pressure surface 13a side of the axial blower 11 configured as described above by an arrow line. FIG. 5 shows a blade cross section when cut in the circumferential direction of the blower at an arbitrary position of the blade 13 that is a predetermined distance r _{1 in the} radial direction from the center of the boss portion 2 as shown in FIG. 4 and an air flow U flowing through the blade cross section. Shows the state. In these drawings, the arrow line indicates the air flow direction, and the rotation of the arrow line indicates the vertical vortex row Uz.
[0028]
As shown in FIGS. 4 and 5, in the axial blower 11, the air flow U flowing from the front edge fillet of the front edge portion 13 c onto the blade suction surface 13 a is transferred to the outer streamline rib row 14 a and the inner streamline. Each passes through the rib row 14b to become a vertical vortex row Uz, and transitions from the laminar boundary layer to the turbulent boundary layer on the blade suction surface 13a. Thereby, the width | variety of the wake vortex fz which makes the cause of blowing sound can be narrowed, and blowing sound can be reduced.
[0029]
Moreover, according to this axial blower 11, the rib rows of the streamlined ribs 14 are the inner and outer two rows 14b, 14a, so that the air flow U passes through the inner streamlined rib rows 14b, 14a. The vertical vortex street Uz can be generated twice on the negative pressure surface 13a. For this reason, since the generation amount of the longitudinal vortex row Uz can be increased as compared with the conventional axial blower 1 shown in FIG. The width of fz can be further narrowed, and the amount of blown air can be further reduced accordingly. The streamline ribs 14b may be provided in three or more rows.
[0030]
Then, the inner flow linear ribs column 14b as shown in FIG. 6, the longitudinal length L ₂ along the fan circumferential direction of the aerodynamic ribs 14, the outer flow linear rib row 14a each aerodynamic ribs 14 than the longitudinal length L ₁ along the fan circumferential direction to form short, it is formed, for example, in 0.8 L _1. Further, the radial intervals W of the streamlined ribs 14 in the inner streamlined rib row 14b are set to be substantially equal.
[0031]
Further, as shown in FIG. 7, the streamline ribs 14 of the inner streamline rib row 14b are arranged at positions corresponding to the gaps between the streamline ribs 14 adjacent to each other in the blower radial direction of the outer streamline rib row 14a. ing.
[0032]
Furthermore, as shown in FIG. 8, the center of a virtual arc curve 15a connecting the leading edges (right ends in FIG. 8) of each streamline rib 14 of the outer streamline rib row 14a is P, and its radius is ra. Sometimes, the leading edge of each streamlined rib 14 of the inner streamlined rib row 14b is positioned on a virtual arc curve 15b concentric with the center P and having a radius rb larger than the radius ra. ing.
[0033]
Further, as shown in FIG. 9, the width Wa in the blower radial direction of each streamline rib 14 in the outer streamline rib row 14a and the width Wb in the blower radial direction of each streamline rib 14 in the inner streamline rib row 14b. They are formed with almost the same width.
[0034]
FIG. 10 shows an arcuate section 14c when each streamlined rib 14 of the inner streamlined rib row 14b is cut along the circumferential direction of the blower. The arcuate section 14c is formed on the blade leading edge 13c side. Rc> rd is established when the radius of curvature of the front half portion 14c1, which is a part, is rc, and the radius of curvature of the rear half portion 14c2, which is the other portion, is rd.
[0035]
By the way, as shown in FIG. 11, the thickness h ₀ of the blade cross section along the blower radial direction of the leading edge portion 13c of each blade 13 is removed so as to gradually decrease from the boss portion 12 side Za to the blade outer periphery 13e side Zb. It has been changed.
[0036]
On the other hand, as shown in FIG. 12, the height of each streamlined rib 14 is gradually changed so as to gradually increase from the boss 12 side Ya toward the blade outer periphery 13e side Yb, and the flow closest to the blade outer periphery 13e. The height h ₁ of the linear rib and the height h ₂ of the streamline rib 14 closest to the boss portion 12 are formed so that h ₁ = 2h ₂ . That is, the direction in which the height of each streamline rib 14 increases and the direction in which the thickness of the blade suction surface side front edge portion 13c increases are opposite to each other, and thus the thickness h _{0 of the} front edge portion 13c. approximately equal at any point is cross-sectional thickness h _t, including. For this reason, shortening of the cooling time of integral molding at the time of resin molding of the axial blower 11, and meat sinking can be prevented or reduced.
[0037]
As described above, the axial blower 11 has the length L ₂ in the longitudinal direction, the installation interval W, the installation position, the position of the front edge, the width Wb, and the arc outer surface of each streamline rib 14 of the inner streamline rib row 14b. Since the curvature and the like are respectively set, the longitudinal vortex train can be stably generated on the blade suction surface 13a, and the blowing sound can be further reduced.
[0038]
【The invention's effect】
As described above, according to the present invention, a plurality of streamlined ribs smoothly connected from the leading edge of the blades on the suction surface side front edge portion of each blade are arranged side by side. A longitudinal vortex train can be generated to suppress the separation of the flow. As a result, the width of the wake vortex formed behind the blade trailing edge can be reduced to reduce the blowing sound. Further, since each streamline rib has a streamline shape, the axial blower can be easily integrally formed by, for example, resin molding, and both improvement in moldability and reduction in manufacturing cost can be achieved.
[Brief description of the drawings]
FIG. 1 is a front view of an overall configuration of an axial blower according to an embodiment of the present invention as viewed from a blade suction surface side.
FIG. 2 is a partially cutaway front view for explaining an inclination angle of a ventilation side surface of each streamline rib in the inner streamline rib row of the axial flow fan shown in FIG.
FIG. 3 is a partially cutaway front view in the case of changing the inclination angle of each streamline rib in the inner streamline rib row of the axial flow fan shown in FIG. 1;
4 is a partially cutaway front view showing a state of air flow on a blade suction surface of the axial blower shown in FIG. 1 and the like. FIG.
[5] blade section view taken along the fan circumferential direction at a radius r ₁ wings axial blower shown in FIG.
6 is a partially cutaway front view showing the length of each streamline rib in the inner streamline rib row of the axial flow fan shown in FIG. 1 and the like, and the spacing between the ribs. FIG.
7 is a partial cutaway when each streamline rib of the inner streamline rib row in the axial blower shown in FIG. 1 and the like is arranged at a position corresponding to a gap between each streamline rib of the outer streamline rib row. Front view.
FIG. 8 is a partial notch showing the positional relationship between the front edge of each streamline rib of the outer streamline rib row and the front edge of each streamline rib of the inner streamline rib row in the axial flow fan shown in FIG. Front view.
FIG. 9 is a partially cutaway front view for explaining the width of each streamline rib of the inner and outer streamline rib rows in the axial flow fan shown in FIG. 1 and the like.
FIG. 10 is a longitudinal sectional view of each streamlined rib shown in FIG.
11 is a cross-sectional view taken along the radial direction of the blower at the front edge of the axial flow blower shown in FIG. 1 and the like.
12 is a schematic view showing a cross section when the boss portion and the inner streamline rib row shown in FIG. 1 and the like are cut along the blower radial direction. FIG.
FIG. 13 is a front view of the conventional axial blower when viewed from the negative pressure side.
14 is a partially cutaway front view showing one blade of the conventional axial fan shown in FIG.
15 is a cross-sectional view of a blade when the blade is cut in the circumferential direction at an arbitrary radius from the rotation center of the axial-flow fan shown in FIG.
[Explanation of symbols]
11 Axial flow fan 12 Boss portion 13 Blade 13a Blade suction surface 13c Blade front edge 13d Blade trailing edge 13e Blade outer peripheral end 14 Streamlined rib 14a Outer streamlined rib row 14b Inner streamlined rib row 15a, 15b Outer and inner arc curves

Claims

回転軸が固定されるボス部の外周に、複数の翼を配設した軸流送風機において、
上記各翼の負圧面側前縁部に、その前縁から翼後縁に向けて滑かに連なる流線形リブを、上記前縁部の輪郭線に沿ってボス部と外周端部間に所定の間隔を置いて列状に複数配設し、この流線形リブ列を送風機周方向に所定の間隔を置いて複数列設け、
翼前縁側の外側流線形リブ列よりも送風機周方向内側に設けた内側流線形リブ列の各流線形リブの流入空気の通風方向を案内する通風側面を、回転軸中心Ｏと、翼外周と翼後縁との交点Ｑと、を結ぶ線分ＯＱに対して各々の所定角度でそれぞれ傾斜させ、これらの各傾斜角を翼外周からボス部側の流線形リブに行くに従って大きくすることを特徴とする軸流送風機。In the axial flow fan in which a plurality of blades are arranged on the outer periphery of the boss portion to which the rotation shaft is fixed,
A streamlined rib smoothly connected from the leading edge to the trailing edge of the blade on the suction surface side front edge of each blade is predetermined between the boss and the outer peripheral edge along the contour line of the leading edge. A plurality of the streamlined rib rows are arranged at predetermined intervals in the circumferential direction of the blower.
The ventilation side that guides the ventilation direction of the inflow air of each streamline rib of the inner streamline rib row provided inside the blower circumferential direction from the outer streamline rib row on the blade leading edge side, the rotation axis center O, the blade outer periphery, Inclined at respective predetermined angles with respect to the line segment OQ connecting the intersection point Q with the blade trailing edge, and each of these inclination angles is increased from the outer periphery of the blade toward the streamline rib on the boss portion side. An axial flow blower.

内側流線形リブ列の各流線形リブは、その流入空気の通風方向を案内する通風側面の角度を、上記外側流線形リブ列の通風側面の角度に対して１２°〜１８°の範囲で傾斜させていることを特徴とする請求項１記載の軸流送風機。 Each streamline rib of the inner streamline rib row is inclined at an angle of the ventilation side surface that guides the ventilation direction of the inflow air in a range of 12 ° to 18 ° with respect to the angle of the ventilation side surface of the outer streamline rib row. The axial-flow fan according to claim 1, wherein

内側流線形リブ列の各流線形リブの送風機周方向に沿う長さＬ２を、外側流線形リブ列の各流線形リブの送風機周方向に沿う長さＬ１に対し、ほぼ０．８Ｌ１の長さに形成していることを特徴とする請求項１または２に記載の軸流送風機。 The length L2 along the blower circumferential direction of each streamline rib of the inner streamline rib row is approximately 0.8L1 with respect to the length L1 along the blower circumferential direction of each streamline rib of the outer streamline rib row. The axial-flow fan according to claim 1 or 2, wherein

内側流線形リブ列は、その流線形リブを、外側流線形リブ列の流線形リブ同士の間隙に対応する位置に配設していることを特徴とする請求項１〜３のいずれか１項に記載の軸流送風機。Inner flow linear ribs columns its streamlined ribs, any one of claims 1 to 3, characterized in that it is disposed at a position corresponding to the gap of the aerodynamic ribs between the outer flow linear rib columns An axial flow blower described in 1.

内側流線形リブ列の各流線形リブは、その送風機周方向に沿う断面の外面が円弧面をなし、その円弧外面の翼前縁側一部の円弧曲面の半径ｒｃの方が、その反対側他部の円弧曲面の半径ｒｄよりも大きくなるように一体に形成されていることを特徴とする請求項１〜４のいずれか１項に記載の軸流送風機。Each streamline rib of the inner streamline rib row has an outer surface of a cross section along the circumferential direction of the blower forming an arc surface, and the radius rc of the arc curved surface of the blade leading edge side of the outer surface of the arc is on the opposite side. The axial-flow blower according to any one of claims 1 to 4, wherein the axial blower is integrally formed so as to be larger than a radius rd of an arc curved surface of the portion.