U.S. patent number 3,832,085 [Application Number 05/295,048] was granted by the patent office on 1974-08-27 for automotive fan shroud.
This patent grant is currently assigned to Ford Motor Company. Invention is credited to Raymond Henry DeFauw, Raymond G. Murley.
United States Patent |
3,832,085 |
DeFauw , et al. |
August 27, 1974 |
AUTOMOTIVE FAN SHROUD
Abstract
A shroud enclosing an automotive type fan has ridges projecting
from the internal surface equally spaced circumferentially to
provide a circumferentially undulating pattern to the axial flow of
air forced through the space between the shroud and the fan to
reduce the noise level of the shroud-fan combination.
Inventors: |
DeFauw; Raymond Henry
(Dearborn, MI), Murley; Raymond G. (Dearborn Heights,
MI) |
Assignee: |
Ford Motor Company (Dearborn,
MI)
|
Family
ID: |
23135994 |
Appl.
No.: |
05/295,048 |
Filed: |
October 4, 1972 |
Current U.S.
Class: |
415/119;
123/41.49; 165/135; 415/914; 165/122; 415/185 |
Current CPC
Class: |
F04D
29/526 (20130101); Y10S 415/914 (20130101) |
Current International
Class: |
F04D
29/40 (20060101); F04D 29/54 (20060101); F01d
025/04 () |
Field of
Search: |
;415/182,183,184,185,186,209,DIG.1 ;181/33HA,33HB |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Raduazo; Henry F.
Attorney, Agent or Firm: Zerschling; Keith L. McCollum;
Robert E.
Claims
We claim:
1. An automotive type fan shroud including a generally cylindrical
section adapted to surround and axially enclose a fan and having
circumferentially spaced projections from the internal surface to
provide a circumferentially undulating pattern to the axial flow of
air past the shroud thereby reducing fan-shroud combination noise
level the fan having blades enclosed by the shroud, a radial
clearance space being provided between the inner extremities of the
projections and the outer radial extent of the fan blades.
2. A fan shroud as in claim 1, the projections each having a finger
like appearance oriented parallel to the shroud axis and the
projections together being equally spaced circumferentially around
the shroud internal surface.
3. A fan shroud as in claim 2, the projections having an axially
extending taper at the air entrance end.
Description
This invention relates, in general, to an automotive type fan
shroud. More particularly, it relates to a construction to reduce
the noise level of a fan shroud combination.
The use of a shroud to surround an automotive type fan to increase
the efficiency of airflow through the engine compartment invariably
also increases the noise level of the combination. Devices have
been suggested for reducing the noise level, such as, for example,
changing the curvature in an axial direction of the shroud. Such is
shown, for example, in U.S. Pat. No. 3,334,807, Fan, K. D. McMahan.
Another suggestion is to decrease the turbulence of flow through
the shroud to decrease noise level, as shown, for example, in U.S.
Pat. No. 3,433,403, Fan Inlet Shroud, Gerlitz. It will be noted,
however, that, in both of the above instances, the circumferential
pattern of air as it flows axially through the shroud is the same
as other constructions, the airflow pattern in an axial direction
being changed but not circumferentially.
The invention provides a construction to reduce noise level in
which the circumferential pattern to the flow of air past the
shroud and fan blades is undulating and provided by ridges located
on the internal surface of the shroud equally spaced
circumferentially around the shroud.
It is a primary object of the invention, therefore, to provide an
automotive type fan shroud construction with a reduced noise
level.
It is a further object of the invention to provide a fan shroud
with internal ridges equally spaced circumferentially and
projecting into the path of axial flow of air through the shroud so
as to provide an overall circumferential undulating flow pattern to
the air to reduce the noise level of the fan-shroud
combination.
Other objects, features and advantages of the invention will become
more apparent upon reference to the succeeding detailed description
thereof, and to the drawings illustrating a preferred embodiment
thereof, wherein;
FIG. 1 is an end elevational view of a fan shroud embodying the
invention;
FIG. 2 is a side elevational view of the fan shroud of FIG. 1, with
parts broken away and in section, and,
FIG. 3 shows a modification.
As stated previously, the fan shroud of the invention is adapted to
cooperate with a fan of the automotive type, such as, for example,
that indicated at 10 in phantom in FIGS. 1 and 2. The fan would be
mounted in a conventional manner on the engine, and would generally
be of a stamped steel or similar design having a number (4 in this
case) of circumferentially spaced fan blades 12. It will be
understood of course that the number and spacing and construction
of the fan play no part in the present invention and is optional
insofar as the fan shroud construction is concerned.
The fan shroud in this case consists of a narrow section 14 of a
thin cylinder that circumferentially surrounds and axially encloses
the fan blades. It has a generally smooth exterior surface 16 that
is welded or otherwise suitably secured to a generally rectangular
supporting structure 18. The latter would be secured in a known
manner adjacent the radiator of the motor vehicle for cooperation
of the fan therewith to pull airflow through the radiator into the
engine compartment.
As best seen in FIG. 2, the upper portion of the leading edge of
the fan shroud 16 is formed with a cover for control purposes, for
example, to control the total flow of air and provide proper
restriction, as is common in an automotive fan shroud
installation.
Attached to the inner surface 22 of shroud 14 are a plurality of
ridges or projections 24 that extend axially for approximately an
inch, for example, and are oriented with an axis parallel to the
axis of the shroud. The ridges have a finger-like appearance, and
are equally spaced circumferentially around the shroud inner
surface, for example, in this case, approximately four inches
apart. The ridges have a generally hat-shaped or square-like
cross-section, although FIG. 3 indicates that the ridges 24' could
have a half-round cross-section with a radius of approximately 0.25
inches. The radial projection of the ridges defines an annular
clearance space between the ridges and fan blades, as shown. It
will be obvious, of course, that other cross-sectional
configurations could be used without departing from the scope of
the invention. As best seen in FIG. 2, each of the ridges 24 is
tapered axially at its leading edge for a nonturbulent entrance of
the air past the ridges.
From the above, it will be seen that the airflow past the interior
of the shroud as a whole will have a smoothly undulating pattern in
a circumferential direction, but that otherwise the axial flow of
air is essentially in parallel streamlines except for that portion
of air blocked by the cover or baffle 20.
The above construction provides for the smooth entrance of air into
the shroud, with the circumferentially undulating pattern reducing
the shroud fan combination noise level.
While the invention has been described and illustrated in its
preferred embodiments in the drawings, it will be clear to those
skilled in the arts to which it pertains that many changes and
modifications may be made thereto without departing from the scope
of the invention.
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