【０００１】
【発明の属する技術分野】本発明は遠心ファン、特に吸込口での空気の漏れや逆流を抑制することの出来る遠心ファンに関する。
【０００２】
【従来の技術】図５は本発明に係る遠心ファンの要部断面図で、ケーシング１の外周部は、発明技術との関わりが無いので省略している。ケーシング１の吸込口１−１は、風の流れを円滑とするため、通常円弧状断面を持つ円筒状を成し、その先端１−１１は内装される羽根車２の側板内周縁２−２１と近接する形で対向している。このケーシング１と羽根車側板２−２の内周縁２−２１とは、効率よく羽根車２の内周面に空気が流れ込むために、両者の隙間は小さい方が好ましいことは言うまでも無いことであるが、一方が固定部材、他方が回転部材であるため、回転部側の機械精度に依拠する振れの存在によって限界がある。
【０００３】両者の回転による軸方向の接触を回避する手段としては、図６や図７に見るように対向するケーシング１の吸込口円筒状先端１−１１と、羽根車２の環状側板内周縁端２−２１との径を変えて、軸方向に直接対向しないことも考えられるが、現実的には、やはり機械的精度による径方向の触れでの最小隙間に限界があるほか、通風ガイドとなる両者の表面のずれにより、上述の軸方向に直接対向する構成より漏れや逆流が増大してしまい実用に適さない。
【０００４】
【発明が解決しようとする課題】上述の如き従来の構成は、固定部材であるケーシングの吸込口と回転部材である羽根車端縁との隙間からの空気の漏れや逆流の阻止が充分で無い為効率の低下を惹起し、その改善が課題となっていた。
【０００５】
【課題を解決するための手段】本発明に成る遠心ファンは、蝸牛状ケーシングと、該ケーシングに内蔵される電動機と、該電動機と共にその回転子に一体保持される羽根車と、を備える遠心ファンで、前記ケーシングの吸込口円筒状先端が、羽根車の吸込口環状側板内周縁端に近接して対向すると共に、これと同心状に形成される第２の円筒部を備え、該第２の円筒部の先端が、前記羽根車の吸込口環状側板に近接して対向するように構成され、もしくは、前記羽根車の吸込口環状側板の内周縁端が、ケーシングの吸込口円筒状先端に近接して対向すると共に、これと同心状に形成される円筒状突起部を備え、該円筒状突起部の先端が、前記ケーシング吸込口近傍の裏面に近接して対向するように構成され、もしくは、前記ケーシングの吸込口円筒状先端が、羽根車の吸込口環状側板内周縁端に近接して対向すると共に、これと同心状に形成される第２の円筒部を備え、該第２の円筒部の先端が、前記羽根車の吸込口環状側板に近接して対向し、然も羽根車の吸込口環状側板が、同心状に形成される円筒状突起部を備え、該円筒状突起部の先端が、前記ケーシングの吸込口と第２の円筒部との間の裏面に近接して対向するように構成され、更に好ましくは、羽根車の吸込口環状側板に、前記円筒状突起部と共に外周縁端に円筒状小突起を備え、両者が前記ケーシングの第２の円筒部を径方向に挟む形で対向するように構成されている。
【０００６】
【発明の実施の形態】以下図面によって本発明の実施例を説明する。
【０００７】図１は第１の実施例で、ケーシング１は、その吸込口円筒状先端１−１１が、羽根車２の吸込口環状側板内周縁端２−２１に近接して対向すると共に、これと同心状に形成される第２の円筒部１−１２を備え、該第２の円筒部１−１２の先端が、前記羽根車２の吸込口環状側板２−２に近接して対向するように構成されるもので、上述従来技術の例と、同じ隙間を設けた場合でも、追加して設けられた第２の円筒部１−１２が通気の壁として機能し、漏れ・逆流を抑制する。
【０００８】図２は逆に、羽根車２の吸込口環状側板２−２は、その内周縁端２−２１が、ケーシング１の吸込口円筒状先端１−１１に近接して対向すると共に、これと同心状に形成される円筒状突起部２−２２を備え、該円筒状突起部２−２２の先端が、前記ケーシング１の吸込口近傍の裏面に近接して対向するように構成されるもので、上述第１の例と同様羽根車２の円筒状突起部２−２２が通気の壁として機能し、漏れ・逆流を抑制する。
【０００９】図３は、上述２つの構成を複合した構成で、ケーシング１の吸込口円筒状先端１−１１が、羽根車２の吸込口環状側板内周縁端２−２１に近接して対向すると共に、これと同心状に形成される第２の円筒部１−１２を備え、該第２の円筒部１−１２の先端が、前記羽根車２の吸込口環状側板２−２に近接して対向し、然も羽根車２の吸込口環状側板２−２が、同心状に形成される円筒状突起部２−２２を備え、該円筒状突起部２−２２の先端が、前記ケーシング１の吸込口１−１１と第２の円筒部１−１２との間の裏面に近接して対向するように、所謂ラビリンスの構造としたもので、その効果は更に高まることが容易に理解できる。
【００１０】更に、図４の例は、上述第３の例の、羽根車２の吸込口環状側板２−２の外周縁端に、円筒状小突起２−２３を追加することで、２重のラビリンス構造とし、漏洩・逆流防止の効果を一層高めている。
【００１１】
【発明の効果】本発明に成る遠心ファンは、固定部材であるケーシングの吸込口と回転部材である羽根車端縁と間に、実用的な隙間を与えつつ、当該隙間からの空気の漏れや逆流の抑制を高め、ファン効率のアップを実現することが出来る。
【図面の簡単な説明】
【図１】本発明に成る遠心ファンの吸込口部の、第１の例の部分断面図である。
【図２】本発明に成る遠心ファンの吸込口部の、第２の例の部分断面図である。
【図３】本発明に成る遠心ファンの吸込口部の、第３の例の部分断面図である。
【図４】本発明に成る遠心ファンの吸込口部の、第４の例の部分断面図である。
【図５】従来技術で示す本願発明に係る遠心ファンの例の要部断面図である。
【図６】従来技術に成る遠心ファン吸込口部の、別の例の部分断面図である。
【図７】従来技術に成る遠心ファン吸込口部の、第３の例の部分断面図である。
【符号の説明】
１ ケーシング
１−１ 吸込口
１−１１ 吸込口円筒状先端
１−１２ 第２の円筒部
２ 羽根車
２−１ インペラ
２−２ 吸込口環状側板
２−２１ 環状側板の内周縁端
２−２２ 環状側板の円筒状突起部
２−３ 環状側板の外周縁端の円筒状小突起
３ 電動機[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal fan, and more particularly, to a centrifugal fan capable of suppressing air leakage and backflow at a suction port.
[0002]
2. Description of the Related Art FIG. 5 is a sectional view of a main part of a centrifugal fan according to the present invention, and the outer peripheral portion of a casing 1 is omitted because it has no relation to the present invention. The suction port 1-1 of the casing 1 has a cylindrical shape having a generally arc-shaped cross section in order to make the flow of the wind smooth, and the tip 1-11 has an inner peripheral edge 2-21 of a side plate of the impeller 2 to be installed. And in close proximity to each other. Needless to say, the gap between the casing 1 and the inner peripheral edge 2-21 of the impeller side plate 2-2 is preferably smaller in order for air to efficiently flow into the inner peripheral surface of the impeller 2. However, since one is a fixed member and the other is a rotating member, there is a limit due to the presence of run-out depending on the mechanical accuracy of the rotating part side.
As means for avoiding axial contact due to the rotation of the two, as shown in FIGS. 6 and 7, the opposed cylindrical end 1-11 of the suction port of the casing 1 and the inner peripheral edge of the annular side plate of the impeller 2 are used. Although it is conceivable that the diameter is not directly opposed in the axial direction by changing the diameter of the end 2-21, in reality, there is a limit to the minimum clearance in the radial direction due to mechanical accuracy, and there is a limit to the ventilation guide. Due to the difference between the surfaces, leakage and backflow are increased as compared with the above-described configuration in which the surfaces are directly opposed to each other, which is not practical.
[0004]
In the above-mentioned conventional construction, the leakage of air from the gap between the suction port of the casing as the fixing member and the end of the impeller as the rotating member is not sufficiently prevented. As a result, efficiency has been reduced, and improvement has been a problem.
[0005]
SUMMARY OF THE INVENTION A centrifugal fan according to the present invention includes a cochlea-shaped casing, an electric motor incorporated in the casing, and an impeller integrally held by the rotor together with the electric motor. And a second cylindrical portion formed concentrically with the suction port cylindrical end of the casing in close proximity to and facing the inner peripheral edge of the suction port annular side plate of the impeller; The tip of the cylindrical portion is configured to be close to and opposed to the suction side annular side plate of the impeller, or the inner peripheral edge of the suction side annular side plate of the impeller is close to the suction side cylindrical front end of the casing. And a cylindrical protrusion formed concentrically with the cylindrical protrusion, and the tip of the cylindrical protrusion is configured to face and close to the rear surface near the casing suction port, or Suction of the casing The cylindrical distal end is provided with a second cylindrical portion formed concentrically with and opposed to the inner peripheral edge of the suction port annular side plate of the impeller, and the distal end of the second cylindrical portion is The suction-port annular side plate of the impeller is provided with a cylindrical projection formed concentrically, and is opposed to the suction-port annular side plate of the impeller, and the tip of the cylindrical projection is formed of the casing. It is configured so as to be close to and opposed to the back surface between the suction port and the second cylindrical portion. More preferably, a cylindrical small portion is formed on the outer peripheral edge together with the cylindrical protrusion on the suction port annular side plate of the impeller. A projection is provided, and both are configured to face each other with the second cylindrical portion of the casing being sandwiched in the radial direction.
[0006]
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a first embodiment, in which a casing 1 has a suction port cylindrical tip 1-11 which is close to and opposed to an inner peripheral edge 2-21 of a suction port annular side plate of an impeller 2. A second cylindrical portion 1-12 is formed concentrically with the second cylindrical portion 1-12, and a tip of the second cylindrical portion 1-12 is opposed to the suction port annular side plate 2-2 of the impeller 2 in close proximity. Even if the same gap is provided as in the above-described prior art, the additionally provided second cylindrical portion 1-12 functions as a ventilation wall to suppress leakage and backflow. I do.
[0008] Conversely, in FIG. 2, the inlet side annular side plate 2-2 of the impeller 2 has an inner peripheral edge 2-21 opposed to the inlet side cylindrical tip 1-11 of the casing 1 in close proximity, and A cylindrical projection 2-22 is formed concentrically with the cylindrical projection 2-22, and a tip of the cylindrical projection 2-22 is configured to face and close to a back surface near the suction port of the casing 1. The cylindrical projection 2-22 of the impeller 2 functions as a ventilation wall, as in the first example, and suppresses leakage and backflow.
FIG. 3 shows a combined configuration of the above two configurations, in which the cylindrical end 1-11 of the suction port of the casing 1 is opposed to the inner peripheral edge 2-21 of the suction port annular side plate of the impeller 2. A second cylindrical portion 1-12 formed concentrically with the second cylindrical portion 1-12, and the tip of the second cylindrical portion 1-12 is close to the suction side annular side plate 2-2 of the impeller 2; The opposed annular side plate 2-2 of the impeller 2 of the impeller 2 is provided with a cylindrical projection 2-22 formed concentrically, and the tip of the cylindrical projection 2-22 is formed on the casing 1. It is a so-called labyrinth structure so as to be closely opposed to the back surface between the suction port 1-11 and the second cylindrical portion 1-12, and it can be easily understood that the effect is further enhanced.
Further, in the example shown in FIG. 4, a small cylindrical projection 2-23 is added to the outer peripheral edge of the suction side annular side plate 2-2 of the impeller 2 of the third example described above, whereby With a labyrinth structure, the effect of preventing leakage and backflow is further enhanced.
[0011]
The centrifugal fan according to the present invention provides a practical gap between the suction port of the casing as the fixing member and the end edge of the impeller as the rotating member while preventing air leakage from the gap. It is possible to enhance the suppression of the backflow and improve the fan efficiency.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view of a first example of a suction port of a centrifugal fan according to the present invention.
FIG. 2 is a partial cross-sectional view of a second example of a suction port of a centrifugal fan according to the present invention.
FIG. 3 is a partial cross-sectional view of a third example of a suction port of a centrifugal fan according to the present invention.
FIG. 4 is a partial cross-sectional view of a fourth example of a suction port of a centrifugal fan according to the present invention.
FIG. 5 is a sectional view of a main part of an example of a centrifugal fan according to the present invention shown in the prior art.
FIG. 6 is a partial cross-sectional view of another example of a centrifugal fan suction port according to the related art.
FIG. 7 is a partial sectional view of a third example of a centrifugal fan suction port according to the prior art.
[Explanation of symbols]
Reference Signs List 1 casing 1-1 suction port 1-11 suction port cylindrical tip 1-12 second cylindrical portion 2 impeller 2-1 suction port annular side plate 2-21 inner peripheral edge 2-22 of annular side plate Cylindrical protrusion 2-3 of side plate Small cylindrical protrusion 3 at outer peripheral edge of annular side plate
