US3915591A - Flexible blade fan - Google Patents

Flexible blade fan Download PDF

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Publication number
US3915591A
US3915591A US319860A US31986072A US3915591A US 3915591 A US3915591 A US 3915591A US 319860 A US319860 A US 319860A US 31986072 A US31986072 A US 31986072A US 3915591 A US3915591 A US 3915591A
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US
United States
Prior art keywords
blade
fan
hub
thickness
decrease
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US319860A
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English (en)
Inventor
Shigeo Aiki
Takanobu Hori
Masaharu Hayashi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Aisin Corp
Original Assignee
Aisin Seiki Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aisin Seiki Co Ltd filed Critical Aisin Seiki Co Ltd
Application granted granted Critical
Publication of US3915591A publication Critical patent/US3915591A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
    • F04D29/38—Blades
    • F04D29/382—Flexible blades

Definitions

  • ABSTRACT A screw type multiblade molded fan of plastic material comprising a central hub and a plurality of blades radially extending from said hub in an imaginary plane normal to the axis of rotation of the fan, each blade being integral with said hub and curved forwardly away from said plane characterized in that each blade decreases thickness thereof .at the middle portion in cross sectional shape.
  • a flexible trailing portion is provided in each blade by such formation of each blade to thereby decrease an inclination angle of each blade as the rotational speed of the fan is increased. The reduction of the angle is then decreases the air flow which thereby decreases the horsepower requirement and the fan noise as the rotational speed of the fan is increased.
  • FIG. 1 A first figure.
  • FIG. 1 A first figure.
  • This invention relates to multiblade molded plastic fans, and particularly to a fan of the flexible multiblade molded screw type.
  • the screw type multiblade fans which are employed on automotive vehicle engines are driven at a greater speed as the speed of the travelling vehicle is increased. This increases the horsepower requirement due to the increase in air velocity.
  • a principal object of the invention is to provide an improved fan of the flexible multiblade molded plastic type to decrease the horsepower requirement and the noise as the rotational speed of the fan increases.
  • the fan may be beneficially provided with a recess at the foot portion of each blade so as to have the trailing portion separated from the hub and render the remaining part of said blade a leading portion.
  • FIG. 1 is a front view of a preferred embodiment of the invention, wherein however only a fan blade has been specifically represented and the remaining blades have been shown only in their whole or partial general configuration;
  • FIG. 2 is a cross section of a fan blade, in the section being taken along the line II-II in FIG. 1 and in the direction of the arrow;
  • FIG. 3 is a cross sectional view of the embodiment of FIG. 2 in which shown common function by additional symbols for convenience of understanding;
  • FIG. 4 shows a graph showing flow of air relative to the rotational speed of the fan as compared with the flow of air of the conventional fan
  • FIGS. 5(a) and 5(b) are cross sections of other embodiments according to the present invention.
  • FIGS. 1 to 5 the same comprises a hub 1 and a plurality of properly pitched blades 2 integral therewith and extended radially therefrom.
  • the said hub and blades are formed of a suitable molded flexible plastic material which is capable of production, especially, by the existing methods of injection molding.
  • the hub l is formed with a central opening 3 to provide means for mounting on a shaft (not shown) driven by the known engine driving shaft through a band (not shown) in the known manner. About the opening 3, are provided a suitable number of spaced holes 4 to provide means to rotate the hub 1 together with the driven shaft.
  • Each of the blades is reduced at its bottom portion as at 5 so that a trailing portion 6 is formed separately from the hub and the remaining part of the blade is rendered a leading portion 8.
  • the trailing portion 6 is deflected by centrifugal force: and that of the contacting air as the rotational speed of the fan is increased.
  • the air flow may be maintained substantially constant, thereby reducing the horsepower requirement as the speed of rotation in the direction of arrow A of the fans is increased.
  • a fan of this type will have special applications on an automotive engine as a substantial flow of air is required when the engine is idling or driving the vehicle at low speed, which requirement progressively reduces as the speed of the vehicle increases. If the same amount of air is propelled by the blades of the fan at high speed a substantial amount of horsepower is required, resulting in inefficient operation of the vehicle.
  • the flexible blade type of fan as herein illustrated and described, the increased speed will progressively flatten the blades 2 namely an inclination angel a in FIG. 2 is reduced to increasing degree of rotational speed of the fan.
  • the blades will maintain the initial form and produce a maximum flow of air.
  • the blades will flatten and produce a decrease in air flow which thereby decreases such horsepower requirement and the noise which would be increased if the flow of air were increased.
  • the fan of the present invention is further characterized in that, means to flatten the blade is better provided by combining two or more types of blade different in thickness so that a cross section of the resultant complexed blade varies in successive steps to alternation of types of blade.
  • the fan may beneficially and additionally be provided in practical use with a recess at the bottom of each blade as shown in FIGS. 1 and 2. If the leading portion 8 shown in FIG. 2 is combined with another imaginary trailing portion 6' indicated in dot and dash line in FIG. 2, a full section of a single type of blade is obtained in the absence of the proposal of the invention, while resulting another full cross section of another single type of blade from combining the trailing portion 6 with another imaginary leading portion 8' indicated by the broken line in the view.
  • the centrifugal force CF. is divided into a horizontal component II.C. and vertical component V.C. as indicated in FIG. 1.
  • the horizontal component BC. is further divided into peripheral component RC. and normal component N.C. as shown in FIG. 3.
  • the normal component N.C. seves substantially to rotate or swing the blade 2 about the axis X of the leading portion 8.
  • the torque about the axis X is derived from the foregoing as l X N.C., while 1 being an arm defined by the axis X and center of gravity M as will be seen in FIG. 3.
  • the pressure P of the air shown in FIG. 2 may be divided into a surface component SC. and normal component N.C'.
  • the normal component N.C'. also serves to swing the blade about the axis X.
  • NC. and N.C'. together serve in cooperation to swing the blade 2 or the trailing portion 6 about the axis X in the direction indicated by the arrow B in FIG. 2 when the fan is rotated in the direction indicated by the arrow A in FIG. 1 and as increases the rotational speed.
  • FIGS. 5(a) and 5(b) there are shown two other different embodiments in which two different type blades are combined together to form a complexed cross section of blade in a manner such that any one of the component blades is unsymmetrical relative to the axis of the other component blade.
  • the surface of the resultant blade must be smoothly continued from one type blade to the other type blade for maintaining the irregular eddy current of air at a minimum in operation.
  • a screw type multiblade molded fan of plastic material comprising a central hub and a plurality of blades radially extending from said hub in an imaginary plane disposed normal to the axis of rotation of the fan, each blade being integral with said hub and curved forwardly away from said plane, each blade decreasing in thickness at the middle portion of said blade and then increasing in thickness rearwardly of said middle portion, at least one side of said blade being shaped to reduce said thickness at the middle portion, sections of the blade with different thicknesses being interconnected by smooth continuous surface contours, each blade having at the foot portion thereof a recess so that a trailing portion of each blade is separated from said hub to thereby decrease the horsepower requirement and the fan noise as the rotational speed of the fan increases.
  • a screw type multiblade molded fan of plastic material comprising a central hub and a plurality of blades radially extending from said hub in an imaginary plane disposed normal to the axis of rotation of the fan, each blade being integral with said hub and curved forwardly away from said plane, each blade decreasing in thickness at the middle portion of said blade, at least one side of said blade being shaped to reduce said thickness at the middle portion, sections of the blade with different thicknesses being interconnected by smooth continuous surface contours, each blade having at the foot portion thereof a recess so that a trailing portion of each blade is separated from said hub to thereby decrease the horsepower requirement and the fan noise as the rotational speed of the fan increases, said decrease of the thickness of said blade being on both faces of the blade.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US319860A 1971-12-09 1972-12-29 Flexible blade fan Expired - Lifetime US3915591A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47002956A JPS512647B2 (enrdf_load_html_response) 1971-12-09 1971-12-09

Publications (1)

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US3915591A true US3915591A (en) 1975-10-28

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ID=11543802

Family Applications (1)

Application Number Title Priority Date Filing Date
US319860A Expired - Lifetime US3915591A (en) 1971-12-09 1972-12-29 Flexible blade fan

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US (1) US3915591A (enrdf_load_html_response)
JP (1) JPS512647B2 (enrdf_load_html_response)
DE (1) DE2263310B2 (enrdf_load_html_response)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4347038A (en) * 1979-04-20 1982-08-31 Aisin Seiki Kabushiki Kaisha Flexible blade fan
US4515511A (en) * 1982-12-31 1985-05-07 Siemens Aktiengesellschaft Axial fan with blades that automatically adjust to the direction of rotation
US5884570A (en) * 1995-09-01 1999-03-23 Lincoln; James A. Apparatus and method for propagating grass and other living plants using a sod slurry
RU2136974C1 (ru) * 1994-10-25 1999-09-10 Попков Иван Иванович Осевой трехступенчатый компрессор
US5993158A (en) * 1997-10-17 1999-11-30 Dbs Manufacturing, Inc. Method and apparatus for aeration using flexible blade impeller
EP1205668A3 (en) * 2000-11-13 2002-08-21 BorgWarner Inc. Molded cooling fan
US6622724B1 (en) * 2000-06-19 2003-09-23 Respironics, Inc. Impeller and a pressure support system and method using such an impeller
US9410438B2 (en) 2013-03-08 2016-08-09 Pratt & Whitney Canada Corp. Dual rotor blades having a metal leading airfoil and a trailing airfoil of a composite material for gas turbine engines

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS528204U (enrdf_load_html_response) * 1975-07-05 1977-01-20
JPS5235508U (enrdf_load_html_response) * 1975-09-04 1977-03-12
JPS53103907U (enrdf_load_html_response) * 1977-01-26 1978-08-22
JPS5622499U (enrdf_load_html_response) * 1979-07-27 1981-02-27
JPS57153998A (en) * 1981-03-20 1982-09-22 Aisin Seiki Co Ltd Flexible fan
DE102012000376B4 (de) * 2012-01-12 2013-08-14 Ebm-Papst St. Georgen Gmbh & Co. Kg Axial- oder Diagonalventilator

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1798299A (en) * 1926-12-31 1931-03-31 Antoni Ugo Rotary flexible propeller
US3054355A (en) * 1961-04-25 1962-09-18 Lord Mfg Co Pump
US3584969A (en) * 1968-05-25 1971-06-15 Aisin Seiki Flexible blade fan

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1798299A (en) * 1926-12-31 1931-03-31 Antoni Ugo Rotary flexible propeller
US3054355A (en) * 1961-04-25 1962-09-18 Lord Mfg Co Pump
US3584969A (en) * 1968-05-25 1971-06-15 Aisin Seiki Flexible blade fan

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4347038A (en) * 1979-04-20 1982-08-31 Aisin Seiki Kabushiki Kaisha Flexible blade fan
US4515511A (en) * 1982-12-31 1985-05-07 Siemens Aktiengesellschaft Axial fan with blades that automatically adjust to the direction of rotation
RU2136974C1 (ru) * 1994-10-25 1999-09-10 Попков Иван Иванович Осевой трехступенчатый компрессор
US5884570A (en) * 1995-09-01 1999-03-23 Lincoln; James A. Apparatus and method for propagating grass and other living plants using a sod slurry
US5993158A (en) * 1997-10-17 1999-11-30 Dbs Manufacturing, Inc. Method and apparatus for aeration using flexible blade impeller
US6622724B1 (en) * 2000-06-19 2003-09-23 Respironics, Inc. Impeller and a pressure support system and method using such an impeller
US20040071552A1 (en) * 2000-06-19 2004-04-15 Respironics, Inc. Impeller and a pressure support system and method using such a method
US8074647B2 (en) 2000-06-19 2011-12-13 Ric Investments Llc Impeller and a pressure support system and method using such a method
EP1205668A3 (en) * 2000-11-13 2002-08-21 BorgWarner Inc. Molded cooling fan
EP1719919A3 (en) * 2000-11-13 2007-02-21 BorgWarner Inc. Molded cooling fan
EP1939458A1 (en) 2000-11-13 2008-07-02 Borgwarner, Inc. Molded cooling fan
US9410438B2 (en) 2013-03-08 2016-08-09 Pratt & Whitney Canada Corp. Dual rotor blades having a metal leading airfoil and a trailing airfoil of a composite material for gas turbine engines

Also Published As

Publication number Publication date
JPS512647B2 (enrdf_load_html_response) 1976-01-28
DE2263310A1 (de) 1973-07-12
DE2263310B2 (de) 1978-05-18
JPS4872707A (enrdf_load_html_response) 1973-10-01

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