VENTILATEUR DE REFROIDISSEMENT AVEC CARENAGE

ENGINE COOLING FAN AND FAN SHROUDING ARRANGEMENT

Abrégé anglais

ENGINE COOLING FAN AND
FAN SHROUDING ARRANGEMENT
Abstract of the Disclosure
Compact fan and shroud package for
radiators with fan blades curved rearwardly to
position rotating shroud at optimized distance
from radiator for improved air flow through
radiator.

Revendications

The embodiments of the invention in which an
exclusive property or privilege is claimed are
defined as follows:
1. Vehicle engine cooling fan and shrouding assembly
for forcing cooling air through a radiator forwardly
mounted in a vehicle in which engine coolant is
circulated comprising support means adjacent to the
radiator, a fan shroud and fan mounting shell
operatively secured to said support adjacent to said
radiator, said shell having a peripheral forwardly
extending wall portion with a terminal forward edge
adjacent to the rearward face of said radiator to
provide a large area intake for air flowing there-
through, said shell further having a generally
cylindrical and rearwardly extending portion to provide
a reduced dimensioned air ejector for said shell, spoke
means extending inwardly from said air ejector, a fan
drive motor supported by said spoke means extending
axially into said shell and having an output shaft, a
fan operatively connected to said drive motor and
rotatably mounted in said shell, said fan describing an
area substantially smaller than that of said intake and
having a central hub operatively connected to said
output shaft of said motor, a plurality of arcuately
spaced blades each having a backwardly swept front edge
extending radially outwardly from said hub, an annular
shroud fixed to the outer end portions of said blades
for rotation therewith in said air ejector, said
annular shroud being axially and backwardly positioned
by said blades at predetermined rearward spacing from
said radiator and from a forward surface of said hub to
increase the air space between said fan and said
radiator for the optimized flow of air through said
radiator into said fixed shell and the pumping of said
flow by said fan.

2. Vehicle engine cooling fan and shrouding assembly
for forcing cooling air through a radiator in which
engine coolant is circulated comprising support means
adjacent to the radiator, a fan shroud and fan mount
shell operatively secured to said support adjacent to
and in substantial parallel relationship with said
radiator, said shell having a peripheral forwardly
extending wall portion to provide an intake for air
flowing through the radiator, said shell further having
a generally cylindrical and rearwardly extending
portion to provide a reduced dimensioned air ejector
for said shell, spoke means extending inwardly from
said air ejector, a fan drive motor supported by said
spoke means extending axially into said shell and
having an output shaft, a fan operatively mounted in
said shell, said fan having a central hub with a
forward front face operatively mounted on said output
shaft of said motor, a plurality of arcuately spaced
blades mounted on said hub having leading edges
reversely curved in the direction of rotation and
backwardly swept from said radiator and said front face
of said hub and extending generally radially outwardly
from said hub, an annular shroud having an area
substantially less than the area of said wall portion
of said shell fixed to the end portions of said blades
for rotation in an immersed position in said fixed
ejector and axially positioned by said blades at
predetermined and optimized spacing from said front
face of said hub and said radiator whereby there is
optimized flow of air through said radiator bounded by
said wall portion of said shell for discharge through
said ejector by operation of said fan.

3. Vehicle engine cooling fan and shrouding assembly
for forcing cooling air through a radiator forwardly
mounted in a vehicle and in which engine coolant is
circulated comprising support means adjacent to the
radiator, a fan shroud and fan mounting shell
operatively secured to said support means adjacent to
said radiator, said shell having a peripheral forwardly
extending wall extending forwardly to a front edge to
provide a large area intake for air flowing through the
radiator, said shell further having a generally
cylindrical and rearwardly extending portion to provide
a reduced dimensioned air ejector for said shell, spoke
means extending inwardly from said air ejector, a fan
drive motor supported by said spoke means extending
axially into said shell and having an output shaft, a
fan operatively connected to said drive motor and
rotatably mounted in said shell, said fan having a
central hub, said hub having a forward face operatively
secured to said output shaft and a peripheral wall
extending around a forward portion of said motor, said
fan having a plurality of arcuately spaced blades each
having a backwardly swept front edge extending radially
outwardly from said peripheral wall, an annular shroud
having an area substantially smaller than said area of
said intake and fixed to the outer end portions of said
blades for rotation therewith in said air ejector, said
annular shroud being axially and backwardly positioned
in said ejector by said blades at predetermined spacing
from said radiator and from the front edge of said
peripheral wall of said shell and with respect to said
forward face of said hub to open and optimize spacing
between said fan and said radiator for optimized air
flow through said radiator as defined by the front edge
of said shell and into said fan for discharge thereby.

Description

ENGINE COOLING FAN AND
FA~I SHROIJDING ARRANGEMENT
This invention relat~s to vehicle engine
cooling and more particularly to a new and improved
multibladed engine cooling fan and fan shrouding
arrangement which operates with hiyh efficiency and
reduced noise level in providing improved flow of
cooling air through a radiator while requiring
minimized engine compartment space.
Prior to the present invention, various
engine cooling ~an and fan shrouding arrangements
have been provided for vehicles which have increased
fan efficiency and reduced noises generated by the
fan. ~n some of the more advanced designs, a fixed
shroud and bracket construction has been utilized
to centrally support a fan motor so that a shrouded
fan driven thereby is effectively immersed within
the ~ixed shroud to provide for improved fan
operation. To provide for quantity flow of air
through the radiator outside of the area immediately
in front of the fan, it was necessary to slant the
shrouded fan at an angle with respect to the radiator
to open up the fan to the radiator for the improved
~ide flow of air into the fan. Because of space
restrictions in crowded eng:ine compartments and higher
standards ~or engin~ cooling, compact Ean and fan
shroud packages are needed which will pump larger
volumes of a:ir through larger areas oE the
radiator ~or more efective transfer of the heat
energy from the engine coolant circulated therein.
'rO this end, this invention incorporates
an en~eloping shroud which is ~ixed with respect to
the engine cooling radiator and which has integral
'

bracket structure for supporting the fan motor
centrally therein. The ~an motor drives a multi-
bladed ~an which has specialized blading for
pumping air with improved efficiency and q~lietness
and also for supporting a rotating shroud immersed
within the ~ixed shroud so tha-t there is highly
effective pneumatic sealing of the recirculating
flow paths between the fixed and rotating shroud.
More particularly, in this invention the spaced
and outwardly extending fan blades are curved
rearwardly to effectively support a rotating shroud
a predetermined distance from the rear face of -the
radiator~ With -this rearward position of the
rotating shroud, the radiator is efectively opened
to the fan for increased side flow of air into the
fan and increased cooling o~ the coolant circulation
in the radiatorO Additionally, the rearwardly
curved blades have a curved leading edge to progres~
sively cut into any air turbulence to reduce blade
generated noises~
This fan and fan shroud arrangement
further allows the shrouding to be square]~ mounted
w.ith respect to the radiator and pro~ides for a
thi.nner package for increased clearance between the
fan components and the ~ehicJ.e engine to reduce the
possibility of heat deyradat:ion and to facilitate
serVicing.
These and o-ther Eeatures, objects and
advantages o:E this invention will be more apparent
~orn the fo:l:lowing detailed ~e~cription and drawing
in which:
:Figure 1 i~ an exploded perspective vi.ew
o$ an automotive engirle cooling radiator, cooling
fan and ~an shrouding package, embodying a preferred

embodiment of ~his in~ention;
Figure 2 is a side view partially in
section of the fan and shroud assembly of Figure l
as connected to the radiator and supports therefor;
Figure 3 is an end view taken along
lines 3-3 of Figure 2 with some componen~s removed;
and
Figure 4 is a plan view of a portion of
the fan and shroud with parts broken away taken
generally along lines 4-4 of Figure 2.
Turning now in greater detail to Figure
l, there is shown a conventional engine cvoling
radiator l connected by brackets 3 and 5 to e].onga-
ted upper and lower horizontal radiator supports 7
l~ and 9. The radiator l is preferably positioned at
the front of the vehicle on the outboard side of a
transversely mounted internal combustion engine ll
diagrammatically illustratea in Figure 2.
Engine 11 is hydraulically connected by suitable
hoses to the radiator so that engine cooling
fluids can circulate therebetween and the heat
energy can be dispersed in the radiator.
Disposed between the radiator and the
enyine i~ a cooling Ean and shroud assembly 15
~ 25 ~or inducincJ a 1.ow o air through the radiator
: on demand by conventional thermostat:ic controls
not shown. This assembly includes a fan mounting
bracke~ and ~ixed shroud unit 17 pre~erably molded
Erom a ~u:ltable plastic material. The unit 17 has
3U a box-l:Lk~3 ma.in ~hell 18 with laterally spaced and
downwardly projecting mounting l.egs 19 which fit
: into corr~3sponaing recesses 21 in the lower horizon
t~l suppo:rt 9. Upwardly extending mounting legs 23
have openings formed therein through which ~hreaded

fasteners 25 extend and into threaded connection
with upper radiator support 7 to thereby secure
the unit 17 behind the radiator. The main shell
18 has an open front covering area of the radiator.
The laterally spaced vertical lines 29-29 of ~igure
1 illustrate the side boundary of area X and the
extent of coverage of the fixed shroud. The main
shell has a rearwardly extending ejector 31 integral
with ~he main shell 18 which has a bell-mouthed inlet
portion and an axially extending cylindrical body
portion that termina-tes rearwardly in an annular edge
32. Extending radially inwardly from -the cylindrical
body portion of the ejector 31 are fo~r arcuately
spaced spokes 35 which support at their inner ends
: 15 an annular mounting ring 37 that has a centrali~ed
opening for receiving and supportlng a generally
cylindrical electrical fan drive motor 39. Thîs
motor has an output shaft which drives a fan and
rotating shroud unit 41 molded from a suitable
plastic material. The fan and shroud unit has a
centralized cup~like hub 43 which is drivingly
connected to the output shaft of the ~otor by
threaded fasteners 45. A plu~ality of thin fan
blades 47 cur~e rearwardly from the outer ~eriphery
oE the hub into tip connection with an inner wall of
a bell-mouthed .rotating shroud 49. With these
cuxved blacles~ the rotat:iny shxoud is backed off
o~ ~nd ~c~uared wit~ respect to the rear ~ace of
the rad:iator to an e,xtent irl which there is
cluant:ity ,slde flow of air illustrated b~ flow
axrc)W~ A in~o a low pressure area, indicated by
circ~l~ C on th~ xad.iator which is immediately
in ~ronk of the fan and which generally corresponds

to the diameter of the fanO This provides for
improved radiator cooling hy the shrouded Ean since
there i.s high volume flow through the radiator
immediately in front of the fan, i.e., circle C and
additionally substantial air flow through the
radiator core outside of circle C covered by the
fixed shroud as indicated by the side flow arrows
A. From this region oE low pressure, the fan
discharges air into the engine compartment.
Recirculation of air from the engine compartment
into the entrance of the fan is retarded by the
shroud configuration as explained in U.S. patent
4,329,946 for Shrouded Arrangement for Engine
Cooling Fan issued ~ay 18, 1982.
Figure 4 illustrates the configuration of
blades 47 in providing the rearward set back of the
rotating shroud 49 with respect to the orward face
of the hub. If the blades had no significant
rearward curvature, the rotating shroud would be
positioned substantially closer to the rear face oE
the radiator such as along the plane through a
vertical line along the ront face of hub 43 for
example. With such location, most of ~he air
pumped through the radiator would be through the
area of circle C and the side flow, arrows A, would
be substantially diminished.
In addition to providing for improved
fan cooling operation through rotating shroud
positioning, the fan blades provide for more
eEeicient and c~uieter pumping. $he thin leading
edges S3 Oe the extending Ean blades are
arcuate.ly curved in the direction oE rotation
indicated by arrow R in Figure 3 while sweeping
rea~wardly into connection with the rotating shroud

so tha-t th,ey progressively slice into any substantial
turbulent air flow. With such encounter, there is
reduced an noise as compared to fans with little or
no curvature in the leading edge of their blades.
After entering the blades the twist in the air foil
section from the hub to the rotating shroud illus-
trated in Figure 4 provides for high efficiency
pumping without substantial flow separation.
While a preferred embodiment has been shown
and described to illustrate this invention, other
embodiments employing the concepts and ideas of this
invention will now become apparent to those skilled
in the art. Accordingly, the scope of this invention
is set forth in the following claims.