Note: Descriptions are shown in the official language in which they were submitted.
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.
