FIELD OF THE INVENTION
[0001] The present invention relates to an axial fan comprising a hub and a plurality of
blades. Moreover, the present invention relates to a blade for use in the axial fan
according to the present invention. Furthermore, the present invention relates to
a hub for use in the axial fan according to the present invention. Additionally, the
present invention relates to a pitch defining element for use in the axial fan according
to the present invention. Finally, the present invention relates to a kit comprising
a hub, a plurality of blades and a plurality of pitch defining elements.
BACKGROUND OF THE INVENTION
[0002] In relation to axial fans, the pitch of the blades determine the amount of air which
is caused to be moved by the axial fan, when the fan is rotated. It is known to provide
axial fans with a predetermined pitch, however it is desirable to provide an axial
fan which allows for the pitch to be adjusted.
[0003] Prior art document
US 2009/0028709 (closest prior art) discloses an adjustable fan including a hub having a receiving
surface and a fan blade having a base abutting the receiving surface of the hub. A
plurality of keyways may be positioned in at least one of the receiving surface and
the base. A key may extend between the base and the receiving surface and into at
least one of the plurality of keyways in order to retain the fan blade in a desired
orientation relative to the hub.
[0004] US 4,600,362 discloses an impeller for an axial fan, this impeller comprising a hub transversally
split into two parts each defining recesses into root portions of a plurality of impeller
blades inserted and locked by means of key-pieces when the two parts are joined together.
Each key-piece has two spaced projections on one side for engaging two corresponding
recesses diametrically located in the end surface of the root of each impeller blade
close to the periphery of this end surface, and two equally spaced projections on
its other side for engaging two corresponding recesses provided in the bottom surface
of the recess in the hub. These pairs of projections on both sides of the key-piece
which is preferably ring -shaped, are advantageously shifted from a certain angle
along the circumference of the ring.
[0005] It is an object of one or more embodiments of the present invention, to provide an
axial fan which allows for adjustment of the pitch.
[0006] It is an object of one or more embodiments of the present invention, to provide an
axial fan in which the pitch cannot be adjusted during operation of the fan.
DESCRIPTION OF THE INVENTION
[0007] In a FIRST aspect, the present invention relates to an axial fan comprising a hub
and a plurality of blades each of which extends away from the hub,
wherein each blade defines a blade air moving part which during rotation of the axial
fan causes air to be moved relative to the axial fan, and a blade retaining part;
wherein the hub defines a plurality of hub retaining sockets each of which is adapted
to retain a blade radially by engagement between the hub retaining socket and the
respective blade retaining part;
wherein each blade retaining part on an outer surface defines a plurality of blade
indentations with a first cross-sectional shape, and wherein each hub retaining socket
on an inner surface defines a plurality of socket indentations with a second cross-sectional
shape,
wherein provision of an pitch determining element is one blade indentation and in
one socket indentation causes the blade to be retained at a predetermined pitch angle
relative to the hub, and
wherein the pitch determining element is non-cylindrical.
[0008] By providing a pitch determining element which can be inserted into one socket indentation
and one blade indentation, the blade may be retained relative to the hub in a predetermined
position and thus achieve a predetermined pitch.
[0009] The axial fan according to the present invention may be used in connection with cooling
of an engine/motor such as a combustion engine or an electrical motor. Moreover, the
axial fan may be used in connection with snow blowers, hover-crafts and ventilation
systems such as ventilation systems for use in the farming industry e.g. stables.
[0010] In the context of the present invention, the term "axial fan" shall be understood
as, a fan which is adapted to move air in a direction parallel with the shaft to which
the axial fan is rotated.
[0011] In the context of the present invention, the term 'pitch' shall be understood as
the angle defined between the plane of rotation of the blade during use and the profile
chord of the blade, the profile chord being defined as a line extending through the
leading edge and the trailing edge of the blade, and the plane of rotation having
the rotational axis of the hub as a normal.
[0012] In one embodiment, at least one of - such as all of - the hub retaining sockets defines
two half parts each with a substantially semi-circular cross-section. When the two
half parts are fastened to each other, the pair of substantially semi-circular cross-sections
may define a circular cross-section.
[0013] In one embodiment, the hub defines a proximal hub part which defines a plurality
of hub retaining sockets and a distal hub part which defines the same number of hub
retaining sockets. When the proximal hub part and the distal hub part are fastened
to each other, the plurality of circular cross-sections, may be defined. In these
circular cross-sections, the blade retaining parts of the blades are retained in the
radial, the axial and the circumferential direction.
[0014] It will be appreciated that by providing a plurality of socket indentations on the
inner surface of hub retaining socket and a plurality of blade indentations in the
outer surface of blade retaining part, the blade may be positioned and retained in
a plurality of different positions.
[0015] The hub and the blades are designed such that the pitch of each blade may be set
in connection with the attachment of the blade to the hub. The pitch of the blades
may be changed by disconnecting the blades from the hub and subsequently attaching
the blades to the hub - however at a new pitch angle. The blades may be disconnected
from the hub by disengaging the proximal hub part and the distal hub part. Once these
two parts are disengaged, the each blade may be rotated about an axis extending through
and defining a normal to the axis of rotation of the hub. Once the new pitch angle
has been established, the pitch defining element may be inserted into a blade indentation
and a socket indentation which faces each other. Subsequently, the proximal hub part
and the distal hub part are fastened to each other.
[0016] In the context of the present invention, the term 'axial fan' shall be understood
as any fan which is suitable for cooling an object such as an engine, either by cooling
a radiator which is used to cool a cooling medium that is circulated between the radiator
and the object/engine and/or by cooling the object/engine directly.
[0017] The hub will typically be adapted to be connected to or fastened to an axle which
is rotated so as to cause the fan to rotate. This axle may be an axle which forms
an extension of the axle of the engine.
[0018] The hub and/or the blade may comprise a metal material or a plastic material or a
fibre glass. Examples are iron, aluminium, polycarbonate, polystyrene, polytetrafluoroethylene,
polyamid and polypropolene. It will be appreciated that any other metal or plastic
material may be used.
[0019] The fan comprises a plurality of blades such as four, five, six, seven, eight, nine,
ten, eleven, twelve, thirteen, fourteen etc. The blades will typically be equidistantly
spaced apart circumferentially. The length of the blades may be in the range 200-2000
milimeters, such as 500 milimeters, such as 1000 milimeters, such as 1500 milimeters,
such as 2000 milimeters.
[0020] Each blade defines a blade retaining part and a blade air moving part. The blade
retaining part may define a circular cross-section into which one or more blade indentations
are defined. The blade air moving part may be designed like any blade for moving air,
and the technology is known from the technical field of wind turbines, axial fans,
or any other field of technology when air is moved by means of blades.
[0021] The pitch determining element is non-cylindircal. In one embodiment, the pitch determining
element defines a non-circular cross-section, such as a non-circular cross-section
in a direction transverse to the longitudinal direction of the pitch determining element.
[0022] In one embodiment, the cross-sectional shape of the pitch determining element corresponds
at least to that of the first and second cross-sectional shape, of the blade indentation
and the socket indentation, respectively. In one embodiment, the cross-sectional shape
of the pitch determining element is non-symmetrical. Accordingly, no line of symmetry
may be defined in any direction through the pitch determining element.
[0023] In one embodiment, at least one of - such as both of - the first and the second cross-sectional
shapes defines a polygonal shape such as a triangular shape, such as quadrangular
shape. In one embodiment, at least one of - such as each of - the first cross-sectional
shape and the second cross-sectional shape defines a semi circle.
[0024] When such first and a second cross-sectional shapes opposes each other, a cylindrical
compartment is defined. This may be used to retain the blade retaining part and the
hub retaining sockets relative to each other by insertion of a cylindrical element.
However in some cases, the number and the positions of the blade indentations and
the socket indentations may be found to be coarse, thus not enabling a desired fine
adjustment of the pitch. In these cases, the inventors have found that the provision
of a non-cylindrical element may allow for a finer adjustment of the pitch. Accordingly,
the cross-sectional shape of the pitch determining element may correspond to that
of two semi-circles which are displaces relative to each other. This displacement
provides for the more fine adjustment of the pitch.
[0025] As an example, the line of symmetry of each of the two semi-circles may be displaced
a predetermined distance. The line of symmetry being defined as the line which divides
a semicircle area into two quarter-circle areas. It will be appreciated that the longer
the predetermined distance is, the larger will the change in pitch be, relative to
a situation where the pitch defining element defines a cylindrical shape.
[0026] In one embodiment, the predetermined distance is one millimetres, such as two millimetres,
such as three millimetres, such as four millimetres, such as five millimetres.
[0027] In a SECOND aspect the present invention relates to a blade for an axial fan according
to the first aspect of the invention.
[0028] The invention according to the second aspect may comprise any combination of features
and/or elements of the invention according to the first aspect.
[0029] In a THIRD aspect the present invention relates to a hub for an axial fan according
to the first aspect of the invention.
[0030] The invention according to the third aspect may comprise any combination of features
and/or elements of the invention according to the first aspect.
[0031] In a FOURTH aspect the present invention relates to a pitch defining element according
to the first aspect of the invention.
[0032] The invention according to the fourth aspect may comprise any combination of features
and/or elements of the invention according to the first aspect.
[0033] In a FIFTH aspect the present invention relates to a kit comprising a hub and plurality
of blades and a plurality of pitch defining elements according to the first aspect
of the invention.
[0034] In one embodiment, one of the pitch defining elements comprises a pitch defining
element with a circular cross-section. This pitch defining element may be cylindrical.
[0035] In one embodiment, the plurality of pitch determining elements comprises one non-cylindrical
pitch defining element and one cylindrical pitch determining element.
[0036] The invention according to the second aspect may comprise any combination of features
and/or elements of the invention according to the first aspect.
BRIEF DESCRIPTION OF THE FIGURES
[0037]
Fig. 1 discloses an axial fan comprising a hub and five blades,
Fig. 2 discloses an exploded view of an axial fan comprising a hub and five blades,
Figs. 3a and 3b disclose an end view of a blade with a non-circular pitch-determining
element,
Figs. 4a and 4b disclose an end view of a blade with a circular pitch-defining element,
Figs. 5 discloses the first cross-sectional shape and the second cross-sectional shape
of the pitch defining element,
Figs. 6-8 disclose different embodiments wherein the first cross-sectional shape and
the second cross-sectional shape are displaced relative to each other,
Fig. 9 discloses a pitch defining element with a circular cross-section, and
Fig. 10 discloses a hub into which one blade is inserted.
DETAILED DESCRIPTION OF THE FIGURES
[0038] Figs. 1 and 2 discloses an axial fan 100 comprising a hub 102 and five blades 104.
The hub 102 comprises a proximal hub part 106 which defines five hub retaining sockets
108 (corresponding to the number of blades 104) and a distal hub part 110 which additionally
defines five retaining sockets 108. The proximal hub part 106 is adapted to be fastened
to an axle for rotating the axial fan 100. This axle may be an axle of an engine (not
shown). In one embodiment, the proximal hub part 106 and the distal hub part 110 are
identical such that either of the two hub parts 106,110 may be fastened to the axle
for rotating the axial fan 100.
[0039] As may be seen in Fig. 10, each of the blades 104 comprises a blade air moving part
112 and a blade retaining part 114. The blade air moving part 112 is adapted to move
air located in the area of the axial fan 100 in a direction parallel to the axis of
rotation 116 of the axial fan 100, such that air may be used to cool an engine - either
directly by moving air along an outer surface of the engine and/or by moving air past
or through a radiator (not shown) which is used to circulate a cooling agent inside
the engine. This cooling agent may be water containing an anti-freezing agent or oil.
It will be appreciated that during rotation of the axial fan 100, the axial fan 100
will also move air in a radial direction relative to the axis of rotation 116.
[0040] The blade retaining part 114 is used to retain the blade in relation to the hub 102.
In order to do this, the blade retaining part 114 comprises a narrow zone 118 a wide
zone 120. The two zones 118, 120 are adapted to engage corresponding zones of the
hub retaining sockets 108. Due to the wide zone 120 being provided closer to the axis
of rotation 116 than the narrow zone 118, the blade 104 is retained radially relative
to the hub 102. In this position, the blade is free to be rotated about its radial
axis 122, whereby any pitch may be achieved.
[0041] In order to fix each blade 104 in a predetermined position and with a predetermined
pitch, a pitch defining element 124 is provided. As will be described in further detail
below, the cross-sectional shape of the pitch defining element 124 may determine the
pitch of the blade 104.
[0042] Each pitch defining element 124 is adapted to engage a blade indentation 126 provided
on an outer surface 128 of the blade retaining part 114, and socket indentations 130
provided on an inner surface 132 of each hub retaining socket 108. By providing one
pitch defining element 124 such that it engages one blade indentation 126 and one
socket indentations 130, the blade is prevented from rotating about its radial axis
122.
[0043] In order to allow the blade to be retained at a plurality of different pitch angles,
each outer surface 128 of each blade retaining part 114 defines a plurality of blade
indentation 126. Similarly, each inner surface 132 of each hub retaining sockets 108
defines a plurality of socket indentations 130. It will be appreciated from Figs.
3 and 4 that the plurality of blade indentations 126 allows for different pitch angles,
cf. the angles printed onto the end surface 129 each blade retaining part 114.
[0044] Figs. 3a-9 disclose different embodiments of the pitch defining element 124. In each
case the pitch defining element 124 defines a first cross-sectional shape 134 and
a second cross-sectional shape 136. It will readily be realised that the two shapes
134,136 form one single element. Thus Fig. 5, is only provided for illustrative purposes
as the two shapes 134,136 in Fig. 5 do not form one single element. In the embodiment
of Figs. 4a, 4b and 9, the cross-sectional shape of the pitch defining element 124'
is circular as the pitch defining element 124 defines a cylindrical shape. Thus in
Figs. 4a, 4b and 9, the first cross-sectional shape 134 and the second cross-sectional
shape 136 are aligned. Contrary hereto, the first cross-sectional shape 134 and the
second cross-sectional shape 136 are displaced relative to each other in Figs. 3a,
3b and 6-8. The effect is that the pitch of the blade may be adjusted even finer than
if only the cylindrical pitch defining element 124 is provided. It will be appreciated
that by providing such pitch defining element 124 where the first cross-sectional
shape 134 and the second cross-sectional shape 136 are displaced relative to each
other, the blade indentation 126 and the socket indentations 130 need not be provided
directly opposite each other. Instead the blade indentation 126 and the socket indentations
130 may be displaced the same amount relative to each other, as the first cross-sectional
shape 134 and the second cross-sectional shape 136 are displaced relative to each
other.
1. An axial fan (100) comprising a hub (102) and a plurality of blades (104) each of
which extends away from the hub (102),
wherein each blade (104) defines a blade air moving part (112) which during rotation
of the axial fan (100) causes air to be moved relative to the axial fan, and a blade
retaining part (114);
wherein the hub (102) defines a plurality of hub retaining sockets (108) each of which
is adapted to retain a blade radially by engagement between the hub retaining socket
(108) and the respective blade retaining part (114);
wherein each blade retaining part (114) on an outer surface defines a plurality of
blade indentations (126) with a first cross-sectional shape, and wherein each hub
retaining socket (108) on an inner surface defines a plurality of socket indentations
(130) with a second cross-sectional shape,
wherein provision of a pitch determining element (124) in one blade indentation (126)
and in one socket indentation (130) causes the blade (104) to be retained at a predetermined
pitch angle relative to the hub (102),
characterised in that the pitch determining element (124) is non-cylindrical, and wherein the cross-sectional
shape of the pitch determining element (124) corresponds to that of two semi-circles
which are displaced relative to each other.
2. An axial fan (100) according to claim 1, wherein the cross-sectional shape of the
pitch determining element (124) corresponds at least to that of the first and second
cross-sectional shape.
3. An axial fan (100) according to any of the preceding claims, wherein the cross-sectional
shape of the pitch determining element (124) is non-symmetrical.
4. An-axial fan (100) according to any of the preceding claims, wherein each of the first
cross-sectional shape and the second cross-sectional shape defines a semi circle.
5. An axial fan (100) according to any of the preceding claims, wherein the hub retaining
socket (108) defines two half parts each with a substantially semi-circular cross-section.
6. An axial fan (100) according to any of the preceding claims, wherein the hub (102)
defines a proximal hub part (106) which defines a plurality of hub retaining sockets
(108) and a distal hub part (110) which defines the same number of hub retaining sockets
(108).
7. An axial fan (100) according to any of the preceding claims, wherein the proximal
hub part (106) and the distal hub part (110) are fastened to each other such that
the plurality of circular cross-sections are defined.
8. A blade (104) for an axial fan (100) according to any of claims 1-7.
9. A hub (102) for an axial fan (100) according to any of claims 1-7.
10. A pitch defining element (124) according to any of claims 1-7.
11. A kit comprising a hub (102) and plurality of blades (104) and a plurality of pitch
determining elements (124) according to any of claims 1-7.
12. A kit according to claim 11, further comprising a pitch determining element (124')
with a circular cross-section.
13. A kit according to claim 12, wherein the pitch determining element (124') with the
circular cross-section is cylindrical
1. Axiallüfter (100), umfassend eine Nabe (102) und mehrere Flügel (104), die jeder von
der Nabe (102) weg verlaufen,
wobei jeder Flügel (104) ein Flügelluftbewegungsteil (112), das während der Drehung
des Axiallüfters (100) bewirkt, dass sich Luft bezüglich des Axiallüfters bewegt,
und ein Flügelhalteteil (114) definiert;
wobei die Nabe (102) mehrere Nabenhaltefassungen (108) definiert, die jede zum Halten
eines Flügels radial durch Eingriff zwischen der Nabenhaltefassung (108) und dem jeweiligen
Flügelhalteteil (114) geeignet sind;
wobei jedes Flügelhalteteil (114) auf einer Außenfläche mehrere Flügelvertiefungen
(126) mit einer ersten Querschnittform definiert, und wobei jede Nabenhaltefassung
(108) auf einer Innenfläche mehrere Fassungsvertiefungen (130) mit einer zweiten Querschnittform
definiert,
wobei das Vorsehen eines Steigungsbestimmungselements (124) in einer Flügelvertiefung
(126) und in einer Fassungsvertiefung (130) bewirkt, dass der Flügel (104) in einem
vorgegebenen Steigungswinkel bezüglich der Nabe (102) gehalten ist,
dadurch gekennzeichnet, dass das Steigungsbestimmungselement (124) nicht zylindrisch ist, und wobei die Querschnittform
des Steigungsbestimmungselements (124) jener von zwei Halbkreisen entspricht, die
in Bezug zueinander angeordnet sind.
2. Axiallüfter (100) nach Anspruch 1, wobei die Querschnittform des Steigungsbestimmungselements
(124) zumindest jener der ersten und zweiten Querschnittform entspricht.
3. Axiallüfter (100) nach einem der vorhergehenden Ansprüche, wobei die Querschnittform
des Steigungsbestimmungselements (124) nicht symmetrisch ist.
4. Axiallüfter (100) nach einem der vorhergehenden Ansprüche, wobei jede der ersten Querschnittform
und der zweiten Querschnittform einen Halbkreis definiert.
5. Axiallüfter (100) nach einem der vorhergehenden Ansprüche, wobei die Nabenhaltefassung
(108) zwei Halbteile definiert, die jedes einen im Wesentlichen halbkreisförmigen
Querschnitt aufweisen.
6. Axiallüfter (100) nach einem der vorhergehenden Ansprüche, wobei die Nabe (102) ein
proximales Nabenteil (106), das mehrere Nabenhaltefassungen (108) definiert, und ein
distales Nabenteil (110) definiert, das dieselbe Anzahl Hubhaltefassungen (108) definiert.
7. Axiallüfter (100) nach einem der vorhergehenden Ansprüche, wobei das proximale Nabenteil
(106) und das distale Nabenteil (110) derart aneinander befestigt sind, dass die mehreren
kreisförmigen Querschnitte definiert sind.
8. Flügel (104) für einen Axiallüfter (100) nach einem der Ansprüche 1 bis 7.
9. Nabe (102) für einen Axiallüfter (100) nach einem der Ansprüche 1 bis 7.
10. Steigungsdefinierungselement (124) nach einem der Ansprüche 1 bis 7.
11. Kit, umfassend eine Nabe (102) und mehrere Flügel (104) und mehrere Steigungsbestimmungselemente
(124) nach einem der Ansprüche 1 bis 7.
12. Kit nach Anspruch 11, ferner umfassend ein Steigungsbestimmungselement (124') mit
einem kreisförmigen Querschnitt.
13. Kit nach Anspruch 12, wobei das Steigungsbestimmungselement (124') mit dem kreisförmigen
Querschnitt zylindrisch ist.
1. Ventilateur axial (100) comprenant un moyeu (102) et une pluralité de lames (104)
dont chacune s'étend à distance du moyeu (102),
dans lequel chaque lame (104) définit une partie de déplacement d'air de lame (112)
qui, pendant la rotation du ventilateur axial (100) déplace l'air par rapport au ventilateur
axial, et une partie de fixation de lame (114) ;
dans lequel le moyeu (102) définit une pluralité de douilles de fixation de moyeu
(108) dont chacune est adaptée pour retenir une lame radialement par engagement entre
la douille de fixation de moyeu (108) et la partie de fixation de lame (114) respective
;
dans lequel chaque partie de fixation de lame (114) définit sur une surface extérieure
une pluralité d'indentations de lame (126) avec une première forme de section transversale,
et dans lequel chaque douille de fixation de moyeu (108) définit sur une surface intérieure
une pluralité d'indentations de douille (130) avec une seconde forme de section transversale,
dans lequel la fourniture d'un élément déterminant le pas (124) dans une indentation
de lame (126) et dans une indentation de douille (130) fait que la lame (104) est
retenue à un angle de pas prédéterminé par rapport au moyeu (102),
caractérisé en ce que l'élément déterminant le pas (124) est non-cylindrique, et sachant que la forme de
section transversale de l'élément déterminant le pas (124) correspond à celle des
deux demi-cercles qui sont déplacés l'un par rapport à l'autre.
2. Ventilateur axial (100) selon la revendication 1, dans lequel la forme de section
transversale de l'élément déterminant le pas (124) correspond au moins à celle des
première et seconde formes de section transversale.
3. Ventilateur axial (100) selon l'une quelconque des revendications précédentes, dans
lequel la forme de section transversale de l'élément déterminant le pas (124) est
non symétrique.
4. Ventilateur axial (100) selon l'une quelconque des revendications précédentes, dans
lequel chacune des première et seconde formes de section transversale définit un demi-cercle.
5. Ventilateur axial (100) selon l'une quelconque des revendications précédentes, dans
lequel la douille de fixation de moyeu (108) définit deux moitiés ayant chacune une
section transversale essentiellement semi-circulaire.
6. Ventilateur axial (100) selon l'une quelconque des revendications précédentes, dans
lequel le moyeu (102) définit une partie de moyeu proximale (106) qui définit une
pluralité de douilles de fixation de moyeu (108) et une partie de moyeu distale (110)
qui définit le même nombre de douilles de fixation de moyeu (108).
7. Ventilateur axial (100) selon l'une quelconque des revendications précédentes, dans
lequel la partie de moyeu proximale (106) et la partie de moyeu distale (110) sont
fixées l'une à l'autre de telle sorte que la pluralité de sections transversales circulaires
est définie.
8. Lame (104) pour un ventilateur axial (100) selon l'une quelconque des revendications
1 à 7.
9. moyeu (102) pour un ventilateur axial (100) selon l'une quelconque des revendications
1 à 7.
10. Élément déterminant le pas (124) selon l'une quelconque des revendications 1 à 7.
11. Kit comprenant un moyeu (102) et une pluralité de lames (104) et une pluralité d'éléments
déterminant le pas (124) selon l'une quelconque des revendications 1 à 7.
12. Kit selon la revendication 11, comprenant en outre un élément déterminant le pas (124')
avec une section transversale circulaire.
13. Kit selon la revendication 12, dans lequel l'élément déterminant le pas (124') avec
la section transversale circulaire est cylindrique.