US20160025102A1 - A variable pitch fan and a method for varying the blade pitch in a fan - Google Patents
A variable pitch fan and a method for varying the blade pitch in a fan Download PDFInfo
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- US20160025102A1 US20160025102A1 US14/775,253 US201414775253A US2016025102A1 US 20160025102 A1 US20160025102 A1 US 20160025102A1 US 201414775253 A US201414775253 A US 201414775253A US 2016025102 A1 US2016025102 A1 US 2016025102A1
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- United States
- Prior art keywords
- blades
- variable pitch
- pitch fan
- fan
- mechanical driving
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- 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.)
- Abandoned
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Classifications
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- 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
- F04D29/34—Blade mountings
- F04D29/36—Blade mountings adjustable
- F04D29/362—Blade mountings adjustable during rotation
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- 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
- F04D29/34—Blade mountings
- F04D29/36—Blade mountings adjustable
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D19/00—Axial-flow pumps
- F04D19/002—Axial flow fans
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/002—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by varying geometry within the pumps, e.g. by adjusting vanes
-
- 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
- F04D29/05—Shafts or bearings, or assemblies thereof, specially adapted for elastic fluid pumps
- F04D29/053—Shafts
-
- 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
- F04D29/325—Rotors specially for elastic fluids for axial flow pumps for axial flow fans
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P7/00—Controlling of coolant flow
- F01P7/02—Controlling of coolant flow the coolant being cooling-air
- F01P7/06—Controlling of coolant flow the coolant being cooling-air by varying blade pitch
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C1/00—Flexible shafts; Mechanical means for transmitting movement in a flexible sheathing
- F16C1/10—Means for transmitting linear movement in a flexible sheathing, e.g. "Bowden-mechanisms"
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C1/00—Flexible shafts; Mechanical means for transmitting movement in a flexible sheathing
- F16C1/10—Means for transmitting linear movement in a flexible sheathing, e.g. "Bowden-mechanisms"
- F16C1/12—Arrangements for transmitting movement to or from the flexible member
- F16C1/16—Arrangements for transmitting movement to or from the flexible member in which the end-piece is guided rectilinearly
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Geometry (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
- Auxiliary Devices For And Details Of Packaging Control (AREA)
Abstract
Description
- The invention relates to a variable pitch fan, which may be used in cooling systems, for example for cooling an engine, particularly an engine of an agricultural or industrial machine, such as a tractor. More in general, the variable pitch fan according to the invention may be used to control an air flow, for example in a seeder to blow seeds from a storing tank towards a seeding unit.
- The invention further relates to a method for varying a pitch of the blades in a fan.
- Known tractors comprise a suction fan for sucking air from the external environment and directing the air towards the engine so as to cool the latter during operation. The fan comprises a rotatable housing supporting a plurality of blades. Each blade can be rotated around a respective axis so as so vary the blade pitch. By varying the blade pitch, the flow rate of air sucked by the fan can be adjusted according to the engine temperature.
- In known tractors, the pitch of the blades can be varied by means of adjusting devices that are actuated by a hydraulic or pneumatic fluid. Examples of such adjusting devices are disclosed in U.S. Pat. No. 6,109,871, U.S. Pat. No. 6,644,922, U.S. Pat. No. 6,942,458, U.S. Pat. No. 7,229,250.
- However, using a hydraulic or pneumatic fluid for actuating the adjusting device makes the fan quite complicated and hence expensive, particularly due to the risks of leakage of the hydraulic or pneumatic fluid. For example, in hydraulic systems it is necessary to use rotating sealing elements which need to be replaced quite often since they tend to wear rapidly. Similar drawbacks occur in connection with pneumatic systems.
- An object of the invention is to improve the variable pitch fans and the methods for varying the pitch of the blades in a fan.
- A further object is to provide a variable pitch fan having a structure which is less complicated than known fans.
- Another object is to provide a variable pitch fan which is not excessively expensive to be manufactured and assembled.
- A further object is to provide a method for varying the pitch of the blades in a fan, which is simple to be carried out.
- In a first aspect of the invention, there is provided a variable pitch fan, comprising:
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- a plurality of blades;
- a supporting device for supporting the blades;
- a rotation device for rotating the supporting device around a rotation axis, so that the blades rotate with the supporting device to control an air flow;
- an adjusting device for adjusting a pitch of the blades by tilting each blade around a respective tilt axis, the adjusting device comprising a driven element fixed relative to a blade;
- characterized in that the adjusting device further comprises a mechanical driving element supported by the supporting device so as to rotate with the supporting device, the mechanical driving element being linearly displaceable relative to the supporting device and being coupled to the driven element so that a linear motion of the mechanical driving element is converted into a rotary motion of the driven element around the tilt axis.
- Since the driven element is actuated by a mechanical driving element, there is no need to use a hydraulic or pneumatic fluid to move the driven element. Hence, the structure of the variable pitch fan can be significantly simplified. For example, there is no need to use complicated sealing systems to avoid leakage of the hydraulic or pneumatic fluid during operation of the fan.
- Consequently, also the costs for manufacturing and assembling the variable pitch fan are reduced.
- In an embodiment, the mechanical driving element comprises a rack and the driven element comprises a rotatable element having a toothed portion, particularly a pinion.
- This embodiment provides a particularly simple and reliable way to rotate each blade around the respective tilt axis.
- In an embodiment, the adjusting device comprises a transmission device for transmitting the linear motion to the mechanical driving element.
- The transmission device may be interposed between an actuator and the mechanical driving element.
- In an embodiment, the transmission device comprises a plurality of discrete bodies, particularly rolling bodies such as spheres or rollers, arranged inside a guide interposed between the actuator and the mechanical driving element.
- The discrete bodies are disconnected one from another.
- A thrust element may be associated to the actuator, the thrust element being displaceable by the actuator for pushing the discrete bodies of said plurality towards the mechanical driving element, so as to linearly displace the mechanical driving element.
- In an embodiment, the transmission device is configured to transmit the linear motion along a path comprising an output portion extending coaxially with the rotation axis and an input portion arranged at an angle, in particular perpendicularly, to the rotation axis.
- The guide inside which the discrete bodies of said plurality are movable may extend along the path of the transmission device.
- The discrete bodies, particularly spheres or rollers, allow the linear motion to be transmitted along any desired path from the actuator to the mechanical driving element.
- In particular, the path may exhibit a relatively small curvature radius. In such a case, transmitting the linear motion by means of other transmission systems could be much more complicated.
- The discrete bodies housed inside the guide are particularly simple to be assembled, do not require complicated maintenance operations and do not involve excessive costs.
- In an embodiment, the actuator can displace the mechanical driving element in a first direction such as to increase the pitch of the blades.
- The mechanical driving element is also displaceable in a second direction opposite the first direction. It is thus possible to decrease the pitch of the blades or even to reverse the flow of air through the variable pitch fan.
- In other words, the variable pitch fan can be used both to suck air from the external environment, for example in order to cool the engine, or to blow air towards the external environment, for example towards the mechanical parts of the vehicle in order to clean them from dust, leaves or other dirties.
- In a second aspect of the invention, there is provided a method for varying a pitch of the blades in a variable pitch fan, the variable pitch fan comprising a supporting device rotatable around a rotation axis, the supporting device supporting a plurality of blades, so that the blades rotate with the supporting device to control an air flow, the method comprising the step of tilting each blade around a respective tilt axis for adjusting the pitch of the blades while the supporting device is being rotated around the rotation axis, characterized in that the step of tilting comprises mechanically displacing along a rectilinear stroke a driving element which is coupled to a driven element fixed relative to a blade, thereby converting a linear motion of the driving element into a rotary motion of the driven element around the tilt axis.
- The method according to the second aspect of the invention allows the pitch of the blades to be varied in a simple and effective manner, also while the variable pitch fan is working, without using hydraulic or pneumatic actuating fluids.
- The invention can be better understood and carried out with reference to the attached drawings, which show an exemplificative and non limiting embodiment thereof, in which:
-
FIG. 1 is a front view of a variable pitch fan; -
FIG. 2 is a cross-section taken along plane II-II inFIG. 1 ; -
FIG. 3 is a cross-section taken along a plane perpendicular to plane II-II inFIG. 1 ; -
FIG. 4 is an enlarged perspective view, showing a blade and a portion of an adjusting device for rotating the blade around a tilt axis; -
FIG. 5 is an enlarged perspective view, showing a supporting element provided with anti-rotation means; -
FIG. 6 is a front view showing a manual element for acting on the adjusting device; -
FIG. 7 is a flow chart showing a control procedure for controlling calibration of a sensor capable of detecting the position of the adjusting device; -
FIG. 8 is a flow chart likeFIG. 7 , showing a control procedure according to an alternative embodiment; -
FIG. 9 is a flow chart likeFIG. 7 , showing a control procedure according to another alternative embodiment; -
FIG. 10 is a flow chart showing the steps of a procedure for calibrating the sensor. -
FIGS. 1 to 3 show avariable pitch fan 1 that can be used for several purposes when there is the need to control a flow of air. Thefan 1 can be used as a cooling fan, for example for cooling an engine, particularly an engine of a vehicle such as an agricultural vehicle or an industrial vehicle. Thefan 1 is particularly suitable for cooling the engine of a tractor. - However, the
fan 1 could be used also for cooling other components, for example an electric motor. - As an alternative, the
fan 1 could be used for non-cooling purposes, in particular in a seeder to blow the seeds from a storing tank towards a seeding unit. - If the
fan 1 is used to cool an engine, thefan 1 is designed to suck fresh air from the external environment and to direct the air towards a liquid cooler or radiator. The latter serves for keeping below a threshold limit the temperature of a liquid intended to cool the engine. - The
fan 1 comprises a plurality ofblades 2 supported by a supportingdevice 3. Theblades 2 may be uniformly spaced apart one from another along a peripheral region of the supportingdevice 3. - A rotation device is provided for rotating the supporting
device 3 around a rotation axis X, shown inFIG. 3 . When the supportingdevice 3 rotates around the rotation axis X, also theblades 2 supported by the supportingdevice 3 rotate around the same axis. - In addition, each
blade 2 can be rotated around a respective tilt axis Z by an adjusting device that will be described in detail herebelow. The tilt axis Z of eachblade 2 can be a longitudinal axis of theblade 2, i.e. an axis along which theblade 2 mainly extends. - Each tilt axis Z may be perpendicular to the rotation axis X.
- In particular, the
blades 2 can be rotated in a synchronized manner around the respective tilt axes Z. - By rotating each
blade 2 around the respective tilt axis Z, it is possible to vary the pitch of the blades, i.e. the angle formed between eachblade 2 and its speed vector. The speed vector of ablade 2 is the vector representing the speed of ablade 2 when the latter is rotated around the rotation axis X by the supportingdevice 3. - By varying the pitch of the blades, the flow rate of air sucked by the
fan 1 is varied. It is thus possible to change the quantity of air that is sucked by thefan 1, according to the engine speed and hence according to the engine temperature. - The adjusting device which allows the pitch of the blades to be varied comprises, for each
blade 2, a driven element fixed relative to theblade 2. The driven element may comprise a rotatable element having at least a portion of toothed surface. In particular, each driven element is rotatable around the tilt axis Z of thecorresponding blade 2. - In the example shown in the Figures, the driven element comprises a pinion 4, which may be toothed only in a portion of its external surface. For a
predetermined blade 2, the pinion 4 can be seen inFIG. 4 . - The driven element, particularly the pinion 4, may be fixed to the
corresponding blade 2 by means of a fixing element such as anelastic pin 6, shown inFIG. 3 . - The driven element or pinion 4 is rotated about the corresponding tilt axis Z by a mechanical driving element which may comprise, for example, a
rack 5. Therack 5 may extend along a direction parallel to the rotation axis X. - In an alternative embodiment, the
rack 5 may also extend along a direction which is slightly inclined relative to the rotation axis X. - The
rack 5 may be obtained on acontrol element 7, which is shown in detail inFIG. 4 . - The
control element 7 may comprise a central body 8, which may be hollow, extending around the rotation axis X. From a side surface of the central body 8 a plurality ofracks 5 protrude towards the outside. Theracks 5 can be uniformly spaced from one another. Eachrack 5 can run along the central body 8 parallelly to the rotation axis X. - Between two consecutive racks 5 a space is defined, suitable for receiving a pinion 4 engaging with the
corresponding rack 5. - A plurality of ribs 9 project, for example radially, towards the inside of the central body 8 from the side surface thereof. The function of the ribs 9 will be explained more in detail below.
- By moving the
control element 7 in a direction parallel to the rotation axis X, all theracks 5 are displaced simultaneously by the same amount. Consequently, theracks 5 synchronously drive the pinions 4. Theblades 2 can therefore be rotated around the respective tilt axes Z in a coordinated manner. - The supporting
device 3 may comprise ahousing 13, for example defined by assembling abase shell 11, aclosure shell 35 and acover 12. - The
base shell 11, theclosure shell 35 and thecover 12 may be made of polymeric material. Thebase shell 11 and theclosure shell 35 may be provided with stiffening ribs. Thecover 12, which is attached to theclosure shell 35, serves in this case for dampening vibrations. - Inside the
housing 13, thecontrol element 7 and the pinions 4 are received. Thehousing 13 is provided with a plurality ofholes 14, shown inFIG. 5 , arranged for example radially around the rotation axis X. A stem of eachblade 2 passes through a correspondinghole 14, so that theblade 2 protrudes outside thehousing 13, whereas the pinion 4 is received inside thehousing 13. - An
axial bearing 15, shown inFIG. 3 , is interposed between each pinion 4 and thehousing 13, so as to support thecorresponding blade 2 and decrease friction which is generated as theblade 2 is rotated. - Each
blade 2 may be provided with one ormore balancing masses 10 so as to balance the centrifugal forces acting on theblade 2 during rotation. The balancingmasses 10 can be fixed to theblades 2 outside thehousing 13. In the alternative or in addition, the balancingmasses 10 can be provided inside thehousing 13, for example fixed to the pinions 4, as shown inFIG. 4 . In the example ofFIG. 4 , the balancingmasses 10 are associated to theblades 2 outside and inside thehousing 13. - The rotation device which rotates the supporting
element 3 around the rotation axis X may comprise apulley 18 which can be rotated around the rotation axis X by a belt that is not shown. The belt can be driven for example by a further pulley connected to an engine shaft. - The
pulley 18 is fixed relative to thehousing 13. For example, thepulley 18 can be fastened to thebase shell 11 by means ofremovable fastening elements 19, such as screws. Thefastening elements 19 may pass through holes obtained in a flange of thepulley 18. - The
control element 7 is prevented from rotating relative to thehousing 13 by anti-rotation means that will be described in detail herebelow. - A plurality of
protrusions 16, shown inFIG. 5 , project inside thehousing 13 from thebase shell 11 towards theclosure shell 35. Theprotrusions 16 may be shaped as circular arcs distributed around the rotation axis X. Between two consecutive protrusions 16 agap 17 is defined. - When the
control element 7 is received inside thehousing 13, two consecutive ribs 9 of thecontrol element 7 are received in agap 17 of thehousing 13. In particular, a rib 9 abuts against aprotrusion 16 defining thegap 17 at a side thereof, whereas an adjacent rib 9 abuts against anotherprotrusion 16 defining thesame gap 17 at the other side thereof. Relative rotation between thehousing 13 and thecontrol element 7 is thus avoided. - Hence, the
protrusions 16 of thehousing 13 and the ribs 9 of thecontrol element 7 act as anti-rotation means for preventing a relative rotation between the supportingdevice 3 and thecontrol element 7. The anti-rotation means thus keep the pinions 4 and theracks 5 in a correct relative position in a circumferential direction with respect to the rotation axis X. - On the other hand, the
control element 7 is free to translate relative to thehousing 13 in a direction parallel to the rotation axis X. To this end, a transmission device is provided for transmitting a linear motion to thecontrol element 7. - The transmission device is interposed between an actuator 20 and the
control element 7. Theactuator 20, which can be an electric actuator, generates a linear motion, for example by coupling a rotatable shaft of theactuator 20 to aworm gear 21. The linear motion is then transmitted to thecontrol element 7 by the transmission device via a transmission path. The transmission path may comprise an output portion which is coaxial with the rotation axis X, in particular arranged along the rotation axis X. Upstream of the output portion, an input portion of the transmission path may be provided, which is arranged at an angle to the rotation axis X, in particular perpendicularly to the rotation axis X. This arrangement of the transmission path allows theactuator 20 to be positioned at a side of the rotation axis X. - In an embodiment which is not shown, the input portion arranged at an angle to the rotation axis X may be omitted, and the transmission path may be fully coaxial with the rotation axis X.
- The transmission device may comprise a plurality of discrete bodies, in particular rolling bodies arranged along the transmission path. In the embodiment shown in the Figures, the discrete bodies are shaped as
spheres 22. However, the discrete bodies may have also different shapes, for example rollers. - The
spheres 22 or other discrete bodies are contained inside a guide, particularly configured as atubular guide 23, which is arranged along the transmission path. In the example shown in the Figures, thetubular guide 23 has approximately an “L” shape. - A thrust element is interposed between the actuator 20 and the
spheres 22 for pushing thespheres 22 towards thecontrol element 7. The thrust element may be configured as apin 24 having an end arranged inside thetubular guide 23 and acting on thespheres 22. A further end of thepin 24 may be connected to theworm gear 21. Thepin 24, in addition to transmitting the linear motion from theworm gear 21 to thespheres 22, serves also to prevent thespheres 22 from exiting out of thetubular guide 23. - The
tubular guide 23 is arranged in a stationary position on the vehicle. - In particular, the
tubular guide 23 may be supported by ahub 25, having a central hole coaxial with the rotation axis X through which a horizontal portion of thetubular guide 23 passes. Thehub 25 is arranged in a stationary position on the vehicle, for example because it is fixed to asupport element 26 intended to be fastened to the engine. - The
support element 26 further supports theactuator 20. - A
shaft 27 is partially housed inside thetubular guide 23, at an end of thetubular guide 23 opposite the end which houses thepin 24. Theshaft 27, together with thepin 24, allows thespheres 22 to remain contained inside thetubular guide 23. - The
shaft 27 has a tip which protrudes from thetubular guide 23 and engages with anend element 28. The latter is received in a recess obtained in thecontrol element 7. - Between the
end element 28 and thecontrol element 7, a bearing 29 is interposed. The bearing 29 allows thecontrol element 7 to rotate relative to theend element 28 when thehousing 13 is rotated by thepulley 18. - An elastic element, particularly a
spring 30, is received inside thehousing 13 so as to be interposed between thehousing 13, particularly theclosure shell 35 thereof, and thecontrol element 7. Thespring 30 may be configured to push thecontrol element 7 away from theclosure shell 35. Thespring 30 may have an end region located around the recess of thecontrol element 7 inside which the bearing 29 and theend element 28 are received. - The
pulley 18 is further fastened to anintermediate hub 31 by means of fastening members, such as fastening screws 32. Theintermediate hub 31 is rotatingly supported by thesupport element 26. In particular, a bearingelement 33 may be interposed between theintermediate hub 31 and thesupport element 26 to allow theintermediate hub 31 to rotate relative to thesupport element 26. - The
intermediate hub 31 has a central passage through which thehub 25, thetubular guide 23 and theshaft 27 pass. A predefined clearance is provided between thehub 25 and the central passage of theintermediate hub 31, so that theintermediate hub 31 may rotate relative to thehub 25. - In operation, the
pulley 18 is rotated around the rotation axis X and in turn rotatingly drives thehousing 13, to which it is fastened by thescrews 19. Since theblades 2 are supported by thehousing 13, theblades 2 rotate together with thepulley 18 around the rotation axis X. Air can thus be sucked from the external environment by thefan 1, so as to cool the engine. - When it is desired to vary the pitch of the blades, the
actuator 20 causes theworm gear 21 to be linearly displaced, for example towards thetubular guide 23. Thepin 24, pushed by theworm gear 21, penetrates more deeply inside thetubular guide 23. Thespheres 22 are thus pushed towards thehousing 13. - The
spheres 22 convert the linear motion of thepin 24 from an input direction, which in the example shown is vertical, to an output direction, which in the example shown is horizontal. More in general, the discrete bodies orspheres 22 convert the direction of the linear motion generated by the actuator 20 from the direction in which thepin 24 extends to the direction in which theshaft 27 extends. Thespheres 22 thus displace theshaft 27 towards thehousing 13 along the rotation axis X. - The
shaft 27 in turn displaces theend element 28, which acts on thecontrol element 7 and pushes the latter towards theclosure shell 35 of thehousing 13. Thecontrol element 7 is thus moved along the rotation axis X against the action of thespring 30, which in the example shown is further compressed between thecontrol element 7 and theclosure shell 35 of thehousing 13. Thecontrol element 7 moves inside thehousing 13, whose position along the rotation axis X does not change. - Since the
racks 5 are obtained on thecontrol element 7, by displacing thecontrol element 7 along the rotation axis X, also theracks 5 are displaced in the same direction along a rectilinear stroke. Theracks 5 cause the pinions 4 to rotate around the respective tilt axes Z by an angle which depends on the extent of linear displacement of theracks 5. Consequently, eachblade 2 is rotated around the corresponding tilt axis Z, which causes the pitch of the blades to be varied, e.g. increased. - If it is desired to vary the pitch of the blades in the other direction, for example by decreasing it, an opposite sequence of movements is followed.
- The
actuator 20 is rotated in a direction such as to cause theworm gear 21 to re-enter into a casing of theactuator 20. - The
spring 30 pushes thecontrol element 7 towards thebase shell 11 of thehousing 13 and towards thepulley 18, i.e. towards the left in the example ofFIG. 3 . Theend element 28 and theshaft 27 are thus displaced backwards along the rotation axis X together with thecontrol element 7. Theshaft 27 acts on thespheres 22, which cause thepin 24 to at least partially exit from thetubular guide 23 and follow theworm gear 21. - Since the
control element 7 is pushed towards thebase shell 11 of thehousing 13 by thespring 30, theracks 5 linearly move in the same direction and cause the pinions 4 to rotate in a direction opposite the direction in which the pinions 4 rotated when thepin 24 was caused to penetrate more deeply inside thetubular guide 23. The pitch of the blades is thus varied in a manner opposite to what has been disclosed before. For example, if the pitch of the blades was increased by causing thepin 24 to penetrate more deeply inside thetubular guide 23, the pitch of the blades is now decreased. - It is stressed that it is not necessary to stop the
pulley 18 when it is desired to vary the pitch of the blades. In other words, the pitch of the blades may be varied also when thefan 1 is working, i.e. when the supportingdevice 3 and theblades 2 are being rotated around the rotation axis X. The adjusting device comprising theracks 5 and the pinions 4 is indeed configured to work also while theblades 2 are rotated around the rotation axis X by thepulley 18. - It is clear from the above that the coupling between the driven elements or pinions 4 and the mechanical driving elements or
racks 5 provides a simple and effective manner to vary the pitch of the blades. - In particular, it is no longer necessary to use hydraulic or pneumatic fluids and the system which varies the pitch of the blades can be entirely mechanical. Thus, there is no need to use expensive rotatable sealing elements or to adopt other measures which were required in the prior art devices in order to avoid leakage of the hydraulic or pneumatic fluid. The costs for manufacturing and assembling the
fan 1 can thus be significantly reduced. - The
spheres 22 or other discrete bodies are not in principle an essential feature of thefan 1. For example, thespheres 22 could be replaced by a Bowden cable or another transmission device which allows linear motion to be transmitted from theactuator 20 to thecontrol element 7. - However, the
spheres 22 or other discrete bodies, if present, allow the linear motion to be reliably transmitted along a transmission path having any desired configuration, for example an output portion coaxial with the rotation axis X and an input portion extending at an angle to the rotation axis X. The curvature radius between the input portion and the output portion may be relatively small, even smaller than the curvature radius which might be obtained by using a Bowden cable. Furthermore, thespheres 22 are not particularly expensive, are easy to be assembled and require nearly no maintenance operations. - The
fan 1 can also be quickly disassembled, if there is the need to do so. For example, the supportingdevice 3 and all its associated components, including theblades 2, can be easily separated from thepulley 18 and the engine of the vehicle simply by unscrewing thescrews 19. In order to assemble and/or disassemble the supportingdevice 3, there are no springs that need to be preloaded, no sealing elements that must be properly positioned, and no other components that require to be handled carefully. - The
control element 7 is easily kept in the correct position by the anti-rotation means which prevent the latter from rotating around the rotation axis X relative to thehousing 13. - Furthermore, the
spring 30 keeps thecontrol element 7 in the correct position along the rotation axis X. - More in detail, the
spring 30 has a plurality of functions. First of all, thespring 30 serves to displace theshaft 27 towards the inside of thetubular guide 23 when theactuator 20 is rotated in a direction such as to the cause theworm gear 21 to re-enter inside the casing thereof. Thespring 30 thus allows the components of the adjusting device that are linearly displaceable to be moved backwards towards theactuator 20. - In addition, the
spring 30 also keeps the teeth of theracks 5 constantly pushed against the teeth of the corresponding pinions 4. Any clearances between theracks 5 and the corresponding pinions 4 are thus substantially eliminated. Undesired displacements between theracks 5 and the pinions 4 are consequently avoided, which would wrongly position theblades 2, for example due to vibrations of the vehicle. - More in general, by exerting a linear force directed along the rotation axis X towards the
support element 26, thespring 30 allows clearances between the components of thefan 1 along the rotation axis X to be substantially eliminated. This increases precision in controlling the pitch of the blades. - The
actuator 20 can be such that, if no electric power is supplied thereto, theworm gear 21 remains in a stationary position without re-entering inside the casing of theactuator 20. This is due to the high transmission ratio between a toothed wheel of theactuator 20 and theworm gear 21. - Thus, after moving the
blades 2 according to the desired orientation, theactuator 20 can be disconnected from electric power. Theblades 2 remain in the reached position until theactuator 20 is again supplied with electric power and is driven to change the blades position. Energy can thus be saved during operation of thefan 1, which reduces the operation costs thereof. - As shown in
FIG. 6 , theactuator 20 can be provided with amanual adjusting device 34 comprising for example a knob, which can be used to act on theworm gear 21 in case of failure of theactuator 20. - If the
actuator 20 fails, by manually acting on the manual adjusting device 34 (e.g. by manually turning the knob), theworm gear 21 can be brought into a position corresponding to a desired orientation of theblades 2 around the respective tilt axes Z. The correct flow rate of air sucked through thefan 1 can thus be ensured, according to the working conditions of the vehicle and hence according to the engine temperature. - The
manual adjusting device 34 can also be used if theactuator 20 fails when theworm gear 21 is in its position of maximum protrusion out of the casing. In this case, themanual adjusting device 34 can be used to cause theworm gear 21 to re-enter before disassembling thefan 1, which can help for example in keeping thespheres 22 inside thetubular guide 23. - The
fan 1 may be provided with a sensor, that is not shown, for detecting the position of theracks 5. By knowing the position of theracks 5, a feedback control on the engine temperature can be improved. - The sensor can be for example a Hall effect sensor, a linear position sensor, a proximity sensor or any other sensor which is capable of detecting, directly or indirectly, the position of the
racks 5. - The sensor can be provided inside the
actuator 20, in order to count the number of revolutions of theactuator 20. Since to each revolution of the actuator 20 a preset, small displacement of theracks 5 is associated, from the number of revolutions of the actuator 20 a precise indication of the position of theracks 5 relative to a reference position may be inferred. - Instead of being associated to the
actuator 20, the sensor could be associated to other parts of thefan 1, for example to thecontrol element 7 or to thehousing 13. - The sensor, if present, needs to be calibrated, so that a control unit of the vehicle knows that a preset signal from the sensor corresponds to a well defined position of the
racks 5 and hence to a preset angle of theblades 2. - In particular, the position detected by the sensor can be taken as a reference position, for example a zero position, when the pitch of the blades is at a maximum value, i.e. when the
blades 2 form an angle of 45° around the corresponding tilt axes Z with respect to a plane perpendicular to the rotation axis X. - To this end, a calibration procedure of the kind shown in
FIG. 10 can be used. - When the vehicle is started up, a signal Hout coming from the sensor is read.
- The
actuator 20 is then moved in a direction such as to displace theshaft 27 towards the right inFIG. 3 , i.e. to increase the pitch of the blades. To this end, theactuator 20 is supplied for example with a positive voltage V+. - The signal Hout(i) coming from the sensor at a preset moment i is then read and compared with the previous reading Hout(i) of the signal coming from the sensor.
- If Hout(i)>Hout(i-1), which means that the pitch of the blades is increasing, then the previous action is repeated and the
actuator 20 keeps to be supplied with a positive voltage V+ to continue to increase the pitch of the blades. - If the condition Hout(i)>Hout(i-1) is no more satisfied, then the
control element 7 has reached an end stroke position and the pitch of the blades is at its maximum value. - At this point, the
actuator 20 is stopped and the position of theblades 2 detected by the sensor is taken as a reference position. - The calibration procedure shown in
FIG. 10 can be carried out at various moments during operation of the vehicle. - In a first embodiment, shown in
FIG. 7 , the calibration procedure can be carried out each time the vehicle is started up. - In this embodiment, which is particularly simple, when the vehicle is started up (key on) the calibration procedure is carried out. Thereafter, while the vehicle is working, the position of the
blades 2 detected by the sensor is regularly controlled, until the vehicle is switched off (key off). - In a second embodiment, shown in
FIG. 8 , the calibration procedure is carried out when the vehicle is started up only if it is needed. - To this end, when the vehicle is started up (key on), the control unit reads the last position of the
blades 2 detected by the sensor and checks whether a new calibration procedure is needed, for example on the basis of threshold values stored in the control unit. If a new calibration procedure is needed, then the latter is carried out. If, on the contrary, no new calibration procedure is needed, the vehicle can start working and the position of theblades 2 will normally be controlled during operation. Before switching off the vehicle, the last position of theblades 2 detected by the sensor is saved as current position of theblades 2. - In a third embodiment, shown in
FIG. 9 , the calibration procedure is carried out when the vehicle is started up only in case of need. Furthermore, during operation of the vehicle, the calibration procedure is carried out if two conditions are met: -
- the first condition is that it is found that calibration is needed;
- the second condition is that the position detected by the sensor is greater than a threshold value.
- In a particularly simple embodiment of the
fan 1, the sensor described above could also be missing. - Warning means can be provided for warning the operator if something is going wrong with the
fan 1, e.g. if the sensor detects that theactuator 20 is not capable of generating motion anymore. The warning means could comprise, for example, one or more warning lights or a warning message generated on a screen. - Finally, it is stressed that the coupling between the pinions 4 and the
racks 5 can be used not only to adjust the pitch of the blades when thefan 1 is used as a suction fan, but also to position theblades 2 in such a manner that operation of thefan 1 is reversed, i.e. thefan 1 works as a blowing fan. In the latter way of operation, thefan 1 can be used to blow an air flow against the radiator or other components of the vehicle, particularly in order to clean them. - In the embodiment which has been described with reference to
FIGS. 1 to 5 , the transmission ratio between each mechanical driving element orrack 5 and the corresponding driven element or pinion 4 was constant. In an alternative embodiment, the transmission ratio between each mechanical driving element and the corresponding driven element may be variable, for example because the driven element comprises an elliptical toothed wheel.
Claims (20)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITMO2013A000065 | 2013-03-13 | ||
IT000065A ITMO20130065A1 (en) | 2013-03-13 | 2013-03-13 | FAN WITH VARIABLE PITCH AND METHOD TO CHANGE THE PALLETS STEP IN A FAN. |
PCT/EP2014/054917 WO2014140149A1 (en) | 2013-03-13 | 2014-03-13 | A variable pitch fan and a method for varying the blade pitch in a fan |
Publications (1)
Publication Number | Publication Date |
---|---|
US20160025102A1 true US20160025102A1 (en) | 2016-01-28 |
Family
ID=48227432
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/775,253 Abandoned US20160025102A1 (en) | 2013-03-13 | 2014-03-13 | A variable pitch fan and a method for varying the blade pitch in a fan |
Country Status (4)
Country | Link |
---|---|
US (1) | US20160025102A1 (en) |
EP (1) | EP2971791B1 (en) |
IT (1) | ITMO20130065A1 (en) |
WO (1) | WO2014140149A1 (en) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106523420A (en) * | 2016-12-30 | 2017-03-22 | 潍柴动力股份有限公司 | Variable-angle fan and angle adjustment method thereof |
US20200025208A1 (en) * | 2018-07-23 | 2020-01-23 | Deere & Company | Variable pitch fan assembly with blade pitch indication |
CN111981410A (en) * | 2020-08-24 | 2020-11-24 | 合肥保利新能源科技有限公司 | Outdoor landscape lamp assembly based on wind-solar hybrid power generation technology |
CN112220367A (en) * | 2020-09-30 | 2021-01-15 | 宁波方太厨具有限公司 | Fan blade structure for cooking equipment and oven with structure |
CN112610521A (en) * | 2020-12-17 | 2021-04-06 | 浙江元盛塑业股份有限公司 | Detection apparatus for car silicon oil clutch fan |
US11208905B2 (en) | 2019-05-24 | 2021-12-28 | Johnson Controls Technology Company | Fan assembly for an HVAC system |
CN114127388A (en) * | 2019-07-18 | 2022-03-01 | 赛峰飞机发动机公司 | Turbine module equipped with a system for varying the pitch of the blades of a propeller and with a device for feathering the blades |
CN114382728A (en) * | 2020-10-19 | 2022-04-22 | 广东美的环境电器制造有限公司 | Net cover assembly and fan |
CN114382724A (en) * | 2020-10-19 | 2022-04-22 | 广东美的环境电器制造有限公司 | Fan blade assembly and fan |
CN114718714A (en) * | 2022-04-24 | 2022-07-08 | 东风马勒热系统有限公司 | Autonomous variable fan |
CN114876838A (en) * | 2021-02-05 | 2022-08-09 | 中国航发商用航空发动机有限责任公司 | Blade tip clearance adjusting structure for adjustable stationary blade of impeller and gas compressor using same |
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Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106523420A (en) * | 2016-12-30 | 2017-03-22 | 潍柴动力股份有限公司 | Variable-angle fan and angle adjustment method thereof |
US20200025208A1 (en) * | 2018-07-23 | 2020-01-23 | Deere & Company | Variable pitch fan assembly with blade pitch indication |
CN110748501A (en) * | 2018-07-23 | 2020-02-04 | 迪尔公司 | Variable pitch fan assembly with blade pitch indication |
US11208905B2 (en) | 2019-05-24 | 2021-12-28 | Johnson Controls Technology Company | Fan assembly for an HVAC system |
CN114127388A (en) * | 2019-07-18 | 2022-03-01 | 赛峰飞机发动机公司 | Turbine module equipped with a system for varying the pitch of the blades of a propeller and with a device for feathering the blades |
CN111981410A (en) * | 2020-08-24 | 2020-11-24 | 合肥保利新能源科技有限公司 | Outdoor landscape lamp assembly based on wind-solar hybrid power generation technology |
CN112220367A (en) * | 2020-09-30 | 2021-01-15 | 宁波方太厨具有限公司 | Fan blade structure for cooking equipment and oven with structure |
CN114382728A (en) * | 2020-10-19 | 2022-04-22 | 广东美的环境电器制造有限公司 | Net cover assembly and fan |
CN114382724A (en) * | 2020-10-19 | 2022-04-22 | 广东美的环境电器制造有限公司 | Fan blade assembly and fan |
CN112610521A (en) * | 2020-12-17 | 2021-04-06 | 浙江元盛塑业股份有限公司 | Detection apparatus for car silicon oil clutch fan |
CN114876838A (en) * | 2021-02-05 | 2022-08-09 | 中国航发商用航空发动机有限责任公司 | Blade tip clearance adjusting structure for adjustable stationary blade of impeller and gas compressor using same |
CN114718714A (en) * | 2022-04-24 | 2022-07-08 | 东风马勒热系统有限公司 | Autonomous variable fan |
Also Published As
Publication number | Publication date |
---|---|
ITMO20130065A1 (en) | 2014-09-13 |
EP2971791A1 (en) | 2016-01-20 |
EP2971791B1 (en) | 2021-07-21 |
WO2014140149A1 (en) | 2014-09-18 |
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