U.S. patent application number 14/879944 was filed with the patent office on 2016-04-14 for fan assembly for vehicles.
The applicant listed for this patent is Denso Thermal Systems S.p.A.. Invention is credited to Paolo DURELLO, Francesco MERCOGLIANO.
Application Number | 20160102681 14/879944 |
Document ID | / |
Family ID | 44320298 |
Filed Date | 2016-04-14 |
United States Patent
Application |
20160102681 |
Kind Code |
A1 |
DURELLO; Paolo ; et
al. |
April 14, 2016 |
FAN ASSEMBLY FOR VEHICLES
Abstract
A fan assembly includes a shroud having a through opening,
around which the shroud defines an air conveying ring, a motor-fan
assembly which includes an axial fan rotatable with respect to the
support about an axis of rotation, and a noise-reducing annular
structure, having a plurality of projections which are arranged in
succession in a circumferential direction and extend radially
towards the axis of rotation of the fan, each projection having a
face which is directed towards the axis of rotation and is
substantially parallel thereto, and a plurality of portions
radially recessed towards the air conveying ring.
Inventors: |
DURELLO; Paolo; (Poirino
(Torino), IT) ; MERCOGLIANO; Francesco; (Poirino
(Torino), IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Denso Thermal Systems S.p.A. |
Poirino (Torino) |
|
IT |
|
|
Family ID: |
44320298 |
Appl. No.: |
14/879944 |
Filed: |
October 9, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13456086 |
Apr 25, 2012 |
9180772 |
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14879944 |
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Current U.S.
Class: |
416/192 |
Current CPC
Class: |
F04D 29/326 20130101;
F04D 19/002 20130101; F04D 29/164 20130101; F04D 29/526 20130101;
B60K 11/02 20130101; F01P 5/02 20130101; F01P 1/06 20130101; F04D
25/02 20130101; F04D 29/663 20130101; F04D 29/325 20130101 |
International
Class: |
F04D 29/66 20060101
F04D029/66; F01P 5/02 20060101 F01P005/02; F04D 25/02 20060101
F04D025/02; F01P 1/06 20060101 F01P001/06; F04D 19/00 20060101
F04D019/00; F04D 29/32 20060101 F04D029/32 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 2011 |
IT |
T02011A000362 |
Claims
1. A fan assembly for cooling a radiator, a radiator-condenser
assembly, or a radiator-condenser-intercooler assembly of a
vehicle, comprising: a shroud, having a through opening around
which said shroud defines an air conveying ring, and a support
which is located at the centre of said opening; a motor-fan
assembly carried by said support, which includes an axial fan
rotatable with respect to said support about an axis of rotation;
and a noise reducing ring structure, fixed with respect to the air
conveying ring and surrounding said fan, said ring structure having
a plurality of projections that follow one another in a
circumferential direction and extend radially toward the axis of
rotation of the fan, each projection having a face bounded by side
edges in the circumferential direction, which faces toward said
axis of rotation and is substantially parallel thereto, and a
plurality of recessed portions radially recessed toward the air
conveying ring and alternated with said projections, wherein each
of said recessed portions has a face facing toward the axis of
rotation of the fan, whose profile in axial direction is generally
curvilinear and unparallel to said axis of rotation, wherein said
ring structure is provided with a plurality of first and second
ledge formations which follow one another along the circumferential
direction, each of which having a substantially quadrilateral,
straight or arcuate, top side, and extending in axial direction to
a bottom wall of the air conveying ring, and in radial direction
from a side wall of the air conveying ring, the second ledge
formations projecting radially toward the axis of rotation of the
fan by a greater extent than the first ledge formations, wherein
the air conveying ring has radially inner faces directly facing
toward said axis of rotation, and wherein said second ledge
formations constitute said projections and said first ledge
formations and said radially inner faces of the air conveying ring
constitute said recessed portions.
2. The fan assembly according to claim 1, wherein said ring
structure has a plurality of ring structure portions radially
spaced from a side wall of the air conveying ring, which cooperate
with said side wall for forming corresponding pockets opened
axially toward the air inlet side of the fan assembly.
3. The fan assembly according to claim 2, wherein said pockets are
formed by the second ledge formations in cooperation with the side
wall of the air conveying ring.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a fan assembly for cooling
a radiator.
[0003] 2. Description of the Related Art
[0004] A fan assembly of this type is described in EP 1 914 402.
Fan assemblies with different forms of the annular structure for
reducing the tonal noise are described by the documents U.S. Pat.
Nos. 5,489,186, 6,863,496, 7,481,615 and U.S. Pat. No.
6,874,990.
[0005] As is known, in order to attenuate air recirculation effects
in the fan assembly it is required to reduce as far as possible the
distance between the tip of the fan blades and the air conveying
ring or, in the case of a fan provided with an outer ring which
interconnects the ends of the blades, the distance between this
outer ring and the air conveying ring.
[0006] The fan is the main source of tonal noise; since it consists
of a fairly large number of rotating blades it produces, by its
nature, a "non-stationary lift" which is the main source of
noise.
[0007] The acoustic combination of fan and conveyor, in terms of
combined air volume, has an effect on the spatial distribution and
the directivity of the acoustic pressure field produced by the
"non-stationary lift" and therefore influences the tonal component
of the resultant noise.
[0008] The presence of an air layer between fan and conveyor
contributes functionally to rotation of the fan without interfering
with the structure of the conveyor which supports the fan and
ensures a suitable fluid dynamic interaction for obtaining the
desired pressure difference between upstream side and downstream
side of the fan.
[0009] From a fluid dynamic point of view, reducing the combined
air volume results in an increase in the efficiency, defined as the
ratio between output fluid dynamic power (Q.DELTA.P) and input
electric power (VI); reducing the abovementioned volume in turn
results in an increase in the pressure difference imparted by the
system to the recirculation flows which are generated at the tips
of the blades, therefore opposing the associated losses.
[0010] The existence of an air volume between the conveyor and the
fan causes a general increase in the wide-band noise, but in
particular intensifies the radial modes which maintain the
fluctuations in lift produced by the rotation of the blades; these
fluctuations in lift result in generation of localized
sound-pressure spectral lobes. Moreover, the presence of a wall
surrounding the fan produces sound diffusion and reflection effects
which contribute to the fluctuations of the existing acoustic
field.
[0011] In order to solve these problems, in the past different
noise-reduction structures have been proposed: for example those
described in the documents EP 1,914,402, U.S. Pat. No. 5,489,186,
6,863,496, 7,481,615 and U.S. Pat. No. 6,874,990 mentioned
above.
[0012] The presence of these noise-reduction structures results in
irregularity of the surface of the conveying ring which may have
one or both the effects as mentioned:
[0013] 1) favour diffraction and diffusion of the pressure waves in
a plane perpendicular to the axis of the fan, resulting in random
spatial distribution of the acoustic pressure waves, with a
consequent reduction in the tonal component of the noise
generated;
[0014] 2) induce the formation of vortices inside the spaces which
have the effect of reducing the fluid-dynamic cross-section, thus
preserving the fluid-dynamic performance (lift/head).
SUMMARY OF THE INVENTION
[0015] One object of the present invention is to provide an
alternative form of the noise-reducing annular structure which
diminishes the tonal component of the noise generated by the fan
without altering the efficiency of the system in terms of delivery
air flow rate and head.
[0016] This object is achieved according to the invention by a fan
assembly of the type defined in the introduction in which said
recessed portions (the spaces present between the projections) each
have a face which is directed towards the axis of rotation of the
fan and the profile of which in the axial direction is generally
curvilinear and not parallel to said axis of rotation.
[0017] Preferred embodiments of the invention are defined in the
dependent claims which are to be understood as forming an integral
part of the present description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Further characteristic features and advantages of the fan
assembly according to the invention will become clear from the
following detailed description of an embodiment of the invention
provided with reference to the accompanying drawings and provided
purely by way of a non-limiting example in which:
[0019] FIGS. 1 and 2 are perspective views of a fan assembly not
according to the invention;
[0020] FIG. 3 is a perspective view of a shroud of the fan assembly
according to FIG. 1;
[0021] FIG. 4 is a cross-sectional view of the shroud according to
FIG. 3;
[0022] FIGS. 5 and 6 are cross-sectional views of the fan assembly
according to FIG. 1 along different radial planes;
[0023] FIGS. 7 and 8 are perspective views of an embodiment of the
fan assembly according to the invention;
[0024] FIG. 9 is a perspective view of a shroud of the fan assembly
according to FIG. 7;
[0025] FIG. 10 is a cross-sectional view of the shroud according to
FIG. 7; and
[0026] FIGS. 11 to 13 are cross-sectional views of the fan assembly
according to FIG. 7 along different radial planes.
DETAILED DESCRIPTION
[0027] With reference to FIGS. 1 and 2, 10 denotes a fan assembly
for cooling a radiator, a radiator-condenser assembly or a
radiator-condenser-intercooler assembly of a vehicle. The fan
assembly comprises a shroud 12 preferably made of injection-moulded
plastic and having a form suitable for conveying an air flow
towards a radiator, a radiator-condenser assembly or a
radiator-condenser-intercooler assembly.
[0028] With reference in particular to FIG. 3, the shroud 12 has a
through-opening 14 and a support 16 located at the centre of the
opening 14. The shroud 12 defines an air conveying ring 17 around
the opening 14. The support 16 is connected to the air conveying
ring 17 by means of radial arms 18. A motor-fan assembly denoted by
20 in FIG. 1 is mounted on the support 16. The motor-fan assembly
20 comprises an electric motor 21 and an axial fan 22 made of
injection-moulded plastic. The fan 22 comprises a hub 24 from which
a plurality of blades 26 extends. The fan 22 is rotatable with
respect to the support 16 about an axis of rotation indicated by X
in FIG. 5.
[0029] As can be seen in FIGS. 1 and 2, the fan 22 may be provided
with an outer ring 28 which is joined to the outer ends of the
blades 26. The outer ring 28, if present, is formed by a
substantially cylindrical wall 30 coaxial with the axis of rotation
X and a radial wall 32 contained in a plane perpendicular to the
axis of rotation X.
[0030] The shroud 12 comprises a noise-reducing annular structure
34 which is fixed to or formed integrally with the shroud and is
situated along the air conveying ring 17 and therefore joined to
this ring. The noise-reducing annular structure 34 surrounds the
fan 22 and is provided with a plurality of prism formations 36 with
a quadrilateral base which are arranged in succession in a
circumferential direction. Each prism formation 36 has a preferably
square or rectangular cross-section and extends in an axial
direction from a bottom wall of the air conveying ring 17. Each
prism formation 36 also extends in a radial direction from a side
wall of the air conveying ring 17, forming a projection which
extends radially towards the axis of rotation X of the fan 22. As
can be seen in FIG. 4, the prism formations 36 are hollow
formations, defining respective cavities which emerge on the
radially outer side of the air conveying ring 17, while they are
closed on the radially inner side and on the air inlet side of the
conveyor assembly (top side in the figures).
[0031] Each prism formation 36 has a radially inner face 38, which
is bounded in the circumferential direction by side edges 38a and
is directed towards the axis of rotation X and is substantially
parallel thereto, and a pair of side faces 39 which are parallel to
each other and which extend from the side edges 38a as far as the
air conveying ring 17. According to an embodiment of the invention,
the prism formations are arranged aligned with respect to the
radial direction, namely with side faces 39 parallel with respect
to radial centre lines respectively associated with these prism
formations so that the radially inner face 38 is perpendicular to
these radial lines. According to an alternative embodiment, the
prism formations are arranged slightly out-of-alignment with
respect to the radial direction, namely slightly rotated with
respect to an axis oriented in the axial direction, so that the
radially inner face 38 is arranged at an angle other than
90.degree. with respect to the radial direction.
[0032] The noise-reducing annular structure 34 also comprises a
collar formation 41 extending circumferentially along the air
conveying ring 17 and having a substantially triangular
cross-section, as can be seen in FIG. 6.
[0033] This collar formation 41 extends in an axial direction from
the bottom wall of the air conveying ring 17 and is divided into
collar portions 43 which interconnect the prism formations 36.
These collar portions 43 each have a radially inner face 44 which
is directed towards the axis of rotation X of the fan and the
profile of which in the axial direction is generally curvilinear
and not parallel to the axis of rotation, as can be seen in
particular in FIG. 6. Owing to this arrangement, the collar
portions 43 therefore form portions which are radially recessed
(with respect to the projections formed by the prism formations)
towards the air conveying ring 17.
[0034] The collar portions 43 are also radially spaced from the
side wall of the air conveying ring 17 and co-operate with this
side wall (and with the prism formations 36) so as to form
respective pockets 45 which are axially open towards the air inlet
side of the fan assembly, as can be seen in particular in FIG.
4.
[0035] As can be understood, the noise-reducing annular structure
described above maintains the fluid dynamic interaction between the
fan and conveyor, forming a "labyrinth seal", and diffuses the
reflected noise waves, reducing the tonal component of the noise
produced.
[0036] This is achieved owing to the following measures: [0037] The
presence of faces terminating in defined edges (the faces of the
prism formations) close to the outer ring of the fan has the effect
that the generation of vortices between the fan and the conveyor
can be controlled and the presence of spaces (the recessed collar
portions and the pockets) has the effect that the vortices are able
to dissipate their energy; [0038] The form of the facing wall on
the fan (the collar formation) is such that the fan-conveyor
distance varies continuously in the axial direction so that the
noise reflection impedance varies continuously in the axial
direction; [0039] The alternation of projections (prism formations)
and recessed portions (collar portions) is such that the noise
reflection impedance varies also in the circumferential
direction.
[0040] The small distance between fan and conveyor ensures a good
aerodynamic performance, while the irregular form of the
noise-reducing annular structure prevents sound-wave generating
reflection effects by varying the impedance of the system to noise
in all directions.
[0041] With reference to FIGS. 7 to 12, an embodiment of the fan
assembly according to the invention is now described.
[0042] Parts which correspond to those of the previous example have
been assigned the same reference numbers; these parts will not be
further described.
[0043] The shroud 12 of the fan assembly now shown has a number of
structural differences compared to that described previously, these
differences not being described here since they are not essential
for the purposes of the invention.
[0044] Essentially, the shroud 12 comprises a noise-reducing
annular structure 134 with a form different from that described
previously. This annular structure 134 is fixed to or formed
integrally with the shroud and is situated along the air conveying
ring 17 and therefore joined to this ring. The noise-reducing
annular structure 134 surrounds the fan 22 and is provided with a
plurality of first and second ledge formations 136, 137 which are
arranged in succession in a circumferential direction. Each ledge
formation 136, 137 has a substantially quadrilateral, straight or
arcuate top side and extends in an axial direction as far as a
bottom wall of the air conveying ring 17. Each ledge formation 136,
137 also extends in a radial direction from a side wall of the air
conveying ring 17, forming a projection which extends radially
towards the axis of rotation X of the fan 22. As can be seen in
FIG. 10, the ledge formations 136, 137 are hollow formations. The
first ledge formations 136 define respective cavities which emerge
on the radially outer side of the air conveying ring 17, while they
are closed on the radially inner side and on the air inlet side of
the conveyor assembly (top side in the figures). The second ledge
formations 137, which project radially towards the axis X of the
fan assembly, by a greater amount than the first ledge formations
136, form respective pockets, which will be described further
below.
[0045] Each second ledge formation 137 has a radially inner face
138, which is bounded in the circumferential direction by side
edges 138a and is directed towards the axis of rotation X and is
substantially parallel thereto, and a pair of side faces 139, which
extend from the side edges 138a as far as the air conveying ring
17.
[0046] Each ledge formation 136 has a radially inner face 143 which
is directed towards the axis of rotation X and the profile of which
in the axial direction is generally curvilinear and not parallel to
the axis of rotation, as can be seen in particular in FIG. 13. Some
of the ledge formations 136 have respective radially inner faces
143 which are bounded in the circumferential direction by side
edges 143a and have a pair of side faces which extend from the side
edges 143a as far as the air conveying ring 17. Others of the first
ledge formations 136 are adjacent to at least one of the second
ledge formations 137 so that the respective radially inner faces
143 are connected to one of the side faces 139 of the second
adjacent ledge formation(s) 137.
[0047] In the positions where the ledge formations 136, 137 are
absent, the air conveying ring 17 directly faces the axis of
rotation X. In these positions the air conveying ring 17 therefore
defines portions with a radially inner face 144 which are directed
towards the axis of rotation X of the fan and the profile of which
in the axial direction is generally curvilinear and not parallel to
the axis of rotation, as can be seen in particular in FIG. 12.
[0048] Owing to the arrangement described above, the first ledge
portions 136 and the portions with a radially inner face 144 form
portions which are radially recessed (with respect to the
projections formed by the second ledge formations 137) towards the
air conveying ring 17.
[0049] The second ledge portions 137 are hollow, each of them
having a radially inner wall (along which the respective radially
inner face 138 is formed) which is radially spaced from the side
wall of the air conveying ring 17 and co-operating with this side
wall so as to form a respective pocket 145 which is axially open
towards the air inlet side of the fan assembly, as can be seen in
particular in FIG. 10.
[0050] As can be understood, the noise-reducing annular structure
described above maintains the fluid dynamic interaction between fan
and conveyor, forming a "labyrinth seal", and diffuses the
reflected noise waves, reducing the tonal component of the noise
produced.
[0051] This is achieved owing to the following measures: [0052] The
presence of faces terminating in defined edges (the faces of the
second ledge formations) close to the outer ring of the fan has the
effect that the generation of vortices between the fan and the
conveyor can be controlled and the presence of spaces (the first
ledge formations and the portions with a radially inner face of the
conveying ring and the pockets) has the effect that the vortices
are able to dissipate their energy; [0053] The form of the facing
wall on the fan (the first ledge formations and the radially inner
faces of the conveying ring) is such that the fan-conveyor distance
varies continuously in the axial direction so that the noise
reflection impedance varies continuously in the axial direction;
[0054] The alternation of projections (second ledge formations) and
different-depth recessed portions (the first ledge formations and
the portions with a radially inner face of the conveying ring) is
such that the noise reflection impedance also varies in the
circumferential direction.
[0055] The small distance between fan and conveyor ensures a good
aerodynamic performance, while the irregular form of the
noise-reducing annular structure prevents sound-wave generating
reflection effects by varying the impedance of the system to noise
in all directions.
* * * * *