U.S. patent application number 11/815577 was filed with the patent office on 2008-07-03 for axial ventilator.
This patent application is currently assigned to BEHR GMBH & CO. KG. Invention is credited to Uwe Aschermann.
Application Number | 20080156282 11/815577 |
Document ID | / |
Family ID | 36291948 |
Filed Date | 2008-07-03 |
United States Patent
Application |
20080156282 |
Kind Code |
A1 |
Aschermann; Uwe |
July 3, 2008 |
Axial Ventilator
Abstract
The invention relates to an axial ventilator for the cooling
device of an internal combustion engine, in particular for a motor
vehicle, wherein said axial ventilator comprises a rotatably driven
hub (2) provided with air blades (11-19) which are fixed thereto
and radially inwardly limited by an internal diameter (Di) and
radially outwardly limited by an external diameter (Da). In order
to obtain a small-sized axial ventilator, the ratio between the
internal (Di) and external (Da) diameters is greater than 40%.
Inventors: |
Aschermann; Uwe; (Karlsruhe,
DE) |
Correspondence
Address: |
LEYDIG VOIT & MAYER, LTD
700 THIRTEENTH ST. NW, SUITE 300
WASHINGTON
DC
20005-3960
US
|
Assignee: |
BEHR GMBH & CO. KG
Stuttgart
DE
|
Family ID: |
36291948 |
Appl. No.: |
11/815577 |
Filed: |
February 8, 2006 |
PCT Filed: |
February 8, 2006 |
PCT NO: |
PCT/EP2006/001095 |
371 Date: |
August 28, 2007 |
Current U.S.
Class: |
123/41.49 |
Current CPC
Class: |
F05B 2250/16 20130101;
F04D 29/386 20130101 |
Class at
Publication: |
123/41.49 |
International
Class: |
F01P 7/10 20060101
F01P007/10 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 9, 2005 |
DE |
10 2005 005 977.5 |
Claims
1. An axial fan for a radiator of an internal combustion engine
comprising a rotatably driven hub, with fan blades that are fixed
to said hub and limited radially inward by an inside diameter (Di)
and radially outward by an outside diameter (Da), wherein the ratio
of the inside diameter (Di) to the outside diameter (Da) is greater
than 40 percent.
2. The axial fan according to claim 1, wherein the ratio of the fan
blade areas projected on a fan passage area enclosed between the
inside diameter (Di) and the outside diameter (Da) by the fan
blades to the fan passage area is greater than 60 percent.
3. The axial fan according to claim 1, wherein the fan blades are
crescent-shaped in a direction extending opposite to the air
flow-through direction.
4. The axial fan according to claim 1, wherein each of the fan
blades has a front edge that has a parabolic shape.
5. The axial fan of claim 4, wherein the parabolic shape has an
origin or vertex and a fan passage area is enclosed between (Di)
and (Da), and an intersecting point between the front edge of the
corresponding fan blade coincides with the original or vertex of
the parabolic shape.
6. The axial fan of claim 1, wherein a fan passage area is enclosed
between (Di) and (Da) and the fan passage area has a radius, and
wherein each of the fan blades has a front edge, and an angle of
attack on the front edge, wherein the angle of attack is greater
than 20 degrees over the radius of the fan passage area.
7. The axial fan of claim 1, wherein a fan passage area is enclosed
between (Di) and (Da) and the fan passe area has a radius, wherein
the fan blades have a profile length that is nearly constant over
the radius of the fan passage area.
8. The axial fan according to claim 7, wherein deviations of the
profile length from an average profile length are smaller than
.+-.6 percent.
9. The axial fan according to claim 1, wherein hub ramps are
provided on the hub of the fan arranged such that the hub ramps
respectively ascend opposite to the rotating direction and are
outwardly limited by an outside surface, wherein the hub has a
radius that is essentially constant in the axial direction.
10. A radiator for an internal combustion engine through which a
medium flows, for cooling the internal combustion engine, wherein
said radiator comprises an air passage area, through which an air
flow flows along a first air flow path that can be shut by a louver
in a dynamic pressure mode and through which an air flow flows
along a second air flow path in a fan mode, and wherein the second
air flow path extends through a fan according to claim 1 that is
arranged between the radiator and the internal combustion
engine.
11. The axial fan according to claim 2, wherein each of the fan
blades has a front edge has a parabolic shape.
12. The axial fan according to claim 3, wherein each of the fan
blades has a front edge has a parabolic shape.
13. The axial fan of claim 2, wherein the fan passage area has a
radius and wherein a fan passage area is enclosed between (Di) and
(Da) and the fan passage area has a radius, and wherein each of the
fan blades has a front edge, and an angle of attack on the front
edge, wherein the angle of attack is greater than 20 degrees over
the radius of the fan passage area.
14. The axial fan of claim 3, wherein a fan passage area is
enclosed between (Di) and (Da) and the fan passage area has a
radius, and wherein each of the fan blades has a front edge, and an
angle of attack on the front edge, wherein the angle of attack is
greater than 20 degrees over the radius of the fan passage
area.
15. The axial fan of claim 4, wherein a fan passage area is
enclosed between (Di) and (Da) and the fan passage area has a
radius, and wherein each of the fan blades has a front edge, and an
angle of attack on the front edge, wherein the angle of attack is
greater than 20 degrees over the radius of the fan passage area.
Description
[0001] The invention pertains to an axial fan for a radiator of an
internal combustion engine, particularly of a motor vehicle, with a
rotatably driven hub and with fan blades that are fixed to said
hub, wherein these fan blades are limited radially inward by an
inside diameter and radially outward by an outside diameter.
[0002] A fan of this type has the function of providing a
sufficient quantity of cooling air in instances in which the wind
does not suffice, for example, while driving slowly or when the
motor vehicle is not moving. The required volumetric displacement
of the fan varies significantly depending on the operating state of
the vehicle. At slow speeds, the pressure buildup required for
conveying the cooling air flow is made available by the fan. At
high speeds, the fan impairs the air flow due to the increased
dynamic pressure.
[0003] The invention is based on the objective of developing an
axial fan for a radiator of an internal combustion engine,
particularly of a motor vehicle, which features a rotatably driven
hub and fan blades that are fixed to said hub, wherein these fan
blades are limited radially inward by an inside diameter and
radially outward by an outside diameter, and wherein this axial fan
has a compact design and is realized such that it generates a high
mass flow with high pressure during the operation of the fan.
[0004] In an axial fan for a radiator of an internal combustion
engine, particularly of a motor vehicle, in which a rotatably
driven hub is provided with fan blades that are fixed to said hub
such that the fan blades are limited radially inward by an inside
diameter and radially outward by an outside diameter, this
objective is attained in that the ratio of the inside diameter to
the outside diameter is greater than 40 percent. The dimensions of
the air passage area enclosed between the inside diameter and the
outside diameter are adapted to the size of the radiator in
conventional fans for cooling an internal combustion engine so as
to also ensure a sufficiently large air passage area when driving
fast and when the fan is switched off. According to the present
invention, the fan is realized as small as possible such that a
louver that releases an additional air passage area while driving
fast can be realized as large as possible. The ratio of the inside
diameter to the outside diameter of the fan passage area is
referred to as the hub ratio. Due to the hub ratio of the
invention, an axial fan with a high power density is created.
[0005] One preferred embodiment of the axial fan is characterized
in that the ratio of the fan blade areas that are projected on the
fan passage area by the fan blades to the annular fan passage area
is greater than 60 percent. The ratio of the fan blade areas that
are projected on the fan passage area by the fan blades to the
annular fan passage area is also referred to as the cover ratio.
The cover ratio of the invention ensures that the fan generates a
sufficient air flow at normal speeds.
[0006] Another preferred embodiment of the axial fan is
characterized in that the fan blades are realized in a
crescent-shaped fashion in a direction extending opposite to the
air flow direction. The crescent-shaped design of the fan blades
has proven particularly advantageous within the scope of the
present invention.
[0007] Another preferred embodiment of the axial fan is
characterized in that the front edge of the fan blades is parabolic
in shape. The parabolic design of the front edges of the fan blades
has proven particularly advantageous within the scope of the
present invention.
[0008] Another preferred embodiment of the axial fan is
characterized in that the origin or the vertex of the parabola
respectively coincides with the intersecting point between the
outside diameter of the fan passage area and the front edge of the
corresponding fan blade.
[0009] Another preferred embodiment of the axial fan is
characterized in that the angle of attack on the front edge of the
fan blades is greater than 20 degrees over the radius of the fan
passage area. The term angle of attack refers to the angle between
a radius and a tangent on the front edge of a fan blade.
[0010] Another preferred embodiment of the axial fan is
characterized in that the profile length of the fan blades is
nearly constant over the radius of the fan passage area. The term
profile length refers to the dimension of the fan blades in the air
flow-through direction or in the axial direction.
[0011] Another preferred embodiment of the axial fan is
characterized in that the deviations of the profile length from an
average profile length are smaller than .+-.6 percent.
[0012] In a radiator for an internal combustion engine,
particularly of a motor vehicle, through which a medium flows,
particularly a cooling medium that serves, for example, to cool the
internal combustion engine, and which features an air passage area,
through which an air flow flows along a first air flow path that
can be shut by means of a louver in a so-called dynamic pressure
mode and through which an air flow flows along a second air flow
path in a so-called fan mode, the aforementioned objective is
attained in that the second air flow path extends through a fan of
the above-described type that is arranged between the radiator and
the internal combustion engine.
[0013] Other advantages, characteristics and specifics of the
invention are described in greater detail below with reference to
the figures. In this context, the respective characteristics cited
in the claims and in the description may be significant for the
invention individually or in arbitrary combinations. The figures
show:
[0014] FIG. 1, a schematic representation of an axial fan of the
invention in the form of a top view, and
[0015] FIG. 2, the axial fan according to FIG. 1, wherein the fan
blade areas projected on the fan passage area by the fan blades are
hatched.
[0016] FIG. 1 shows an axial fan 1 that comprises a hub 2 with nine
fan blades 11-19 fixed thereto. The hub is driven in the clockwise
direction, for example, by means of a (not-shown) fluid friction
clutch or an electric motor. The module consisting of the axial fan
1 and the fluid friction clutch serves for conveying cooling air
through the radiator of a motor vehicle. It is assumed that the
design and the function of a motor vehicle radiator are generally
known such that they are not described in greater detail at this
point.
[0017] The fan blades 11-19 have a common inside diameter Di and a
common outside diameter Da. The axial fan 1 features an annular
passage area for air between the inside diameter Di and the outside
diameter Da. When the hub 2 is set in rotation, the fan blades
11-19 turn in the clockwise direction as indicated with an arrow
26. Each fan blade 11-19 has a front edge that is realized in a
parabolic fashion. The front edge of the fan blade 11 is identified
by the reference symbol 28. The front edge of the fan blade 12 is
identified by the reference symbol 29. Part of a parabola 30, the
vertex or origin 31 of which coincides with the intersecting point
between the front edge 28 and the outside diameter Da, is
illustrated on the front edge 28 of the fan blade 11.
[0018] The front edge 29 of the fan blade 12 has an angle of attack
a that is formed between a tangent on the front edge and the
corresponding radius. An angle of attack .alpha.1 is formed between
a tangent T1 and a radius R1. An angle of attack .alpha.2 is formed
between a tangent T2 and a radius R2. An angle of attack .alpha.3
is formed between a tangent T3 and a radius R3. The angles of
attack .alpha.1 to .alpha.3 respectively amount to approximately 40
degrees.
[0019] FIG. 2 shows the axial fan 1 according to FIG. 1 in the form
of a representation identical to that illustrated in FIG. 1,
wherein the fan blade areas that are projected on the annular
surface situated between the outside diameter Da and the inside
diameter Di by the fan blades 11 to 19 are hatched. The ratio
between the projected blade areas and the annular surface of the
axial fan 1 is referred to as the cover ratio. The blade width of
the fan blades 11 to 19 is chosen such that a cover ratio of more
than 60 percent is achieved. The ratio between the inside diameter
Di and the outside diameter Da is referred to as the hub ratio and
amounts to more than 40 percent of the axial fan 1 of the
invention. The fan blades 11 to 19 of the axial fan 1 are
crescent-shaped toward the rear. The angles .alpha.1 to .alpha.3
(see FIG. 1) between the front edge 29 and the corresponding radii
R1, R2, R3 are always greater than 20 degrees.
[0020] All flat front edges follow a parabolic progression as
elucidated using the example of the front edge 28 of the fan blade
11. The origin of the parabola lies at the connection between the
front blade edge 28 and the outside diameter Da that is also
referred to as the envelope. The profile lengths are nearly
constant over the radius. The deviations from the average profile
length are smaller than .+-.6 percent. The design of the invention
makes it possible to realize a very compact fan construction. Due
to the very compact axial fan 1, the louvered surface of the
radiator can be realized correspondingly large.
[0021] According to another embodiment, the axial fan of the
invention may feature hub ramps that may be arranged on the hub of
the fan. Hub ramps that respectively ascend opposite to the
rotating direction and are outwardly limited by an outside surface
may be provided, preferably on the pressure side of the fan. In
this respect, reference is made to DE 41 17 342 C1, the disclosure
of which is hereby expressly incorporated into the disclosure of
the present application.
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