CENTRIFUGAL FAN
A centrifugal fan for use with an engine includes a hub defining a rotational axis, a plurality of blades arranged about the rotational axis, and a screen coupled to the hub and blades for co-rotation therewith. The hub, the blades, and the screen are integrally formed as a single piece.
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The present invention relates to centrifugal fans, and more particularly to centrifugal fans for use with internal combustion engines.
BACKGROUND OF THE INVENTIONCentrifugal fans draw air from an axial direction and discharge a radial airflow. Centrifugal fans are often used for air-cooling internal combustion engines. Centrifugal fans are typically assembled using a number of components having differing materials. Such components are separately formed and fastened together, thereby increasing manufacturing costs and complexity.
SUMMARY OF THE INVENTIONThe present invention provides in one aspect, a centrifugal fan for use with an engine including a hub defining a rotational axis, a plurality of blades arranged about the rotational axis, and a screen coupled to the hub and blades for co-rotation therewith. The hub, the blades, and the screen are integrally formed as a single piece.
The present invention provides, in another aspect, an engine including a crankcase, a cover at least partially enclosing the crankcase, and a centrifugal fan rotatable while the engine is in use for discharging a cooling airflow between the crankcase and the cover. The centrifugal fan includes a hub defining a rotational axis, a plurality of blades arranged about the rotational axis, and a screen coupled to the hub and blades for co-rotation therewith. The hub, the blades, and the screen are integrally formed as a single piece.
Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
DETAILED DESCRIPTIONWith reference to
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The centrifugal fan 30 of the present invention, including the combination of features described above, is formed as a single piece by a suitable molding process such as injection molding. The centrifugal fan 30 may be molded with a relatively simple mold (not shown) that is separable into first and second mold halves. The mold halves may be brought together or separated from one another along a mold axis that is coaxial with the rotational axis 26 of the centrifugal fan 30. With reference to
In contrast to conventional fans (not shown), which require multiple manufacturing steps before the final product is complete, the single piece design is greatly simplified. The molding process allows for accurate and consistent formation of the various features described above without the need for separate machining and fastening operations. In addition, conventional fans often include a base portion (e.g., a flat disk) to which all other components are connected. In the single piece design according to the present invention, the hub 34, the blades 50, 54, and the screen 122 are all integrally formed and do not require any additional base portion. As such, the manufacturing of the centrifugal fan 30 of the present invention is greatly simplified, and material cost and tolerance requirements are reduced.
Various features of the invention are set forth in the following claims.
Claims
1. A centrifugal fan for use with an engine, comprising:
- a hub including a rotational axis;
- a plurality of blades arranged about the rotational axis and coupled to the hub for co-rotation therewith, wherein each blade includes a pressure surface, a suction surface opposite the pressure surface, a leading edge defining a boundary between the suction surface and the pressure surface, and a trailing edge opposite the leading edge; and
- a screen coupled to the hub and the blades for co-rotation therewith, wherein the hub, the blades, and the screen are integrally formed as a single piece, wherein the plurality of blades comprises a plurality of main blades and a plurality of splitter blades, wherein the leading edge of each main blade is integral with the hub and wherein the leading edge of each splitter blade is spaced from the hub.
2. (canceled)
3. The centrifugal fan of claim 1, wherein each of the blades defines
- a nose-tail line connecting the leading edge and the trailing edge, the nose-tail line being a straight line and defining a length; and
- a mean line half-way between the pressure surface and the suction surface and intersecting the nose-tail line at the leading edge and the trailing edge.
4. (canceled)
5. The centrifugal fan of claim 3, wherein each of the blades includes a camber between about 0.1 and about 0.2.
6. The centrifugal fan of claim 5, wherein the plurality of blades comprises a plurality of main blades and a plurality of splitter blades, wherein the camber of the splitter blades is the same as the camber of the main blades.
7. The centrifugal fan of claim 4, wherein the main blades and the splitter blades are alternately spaced about the rotational axis.
8. The centrifugal fan of claim 1, wherein the screen includes a plurality of concentric rings coaxial with the rotational axis and interconnected by the blades.
9. The centrifugal fan of claim 1, wherein each of the blades includes at least one notch in a top edge of the blade, the notch configured to allow an airflow to pass between adjacent blades.
10. An engine comprising:
- a crankcase;
- a cover at least partially enclosing the crankcase; and
- a centrifugal fan that is rotatable while the engine is in use for discharging a cooling airflow between the crankcase and the cover, the centrifugal fan including a hub including a rotational axis, a plurality of blades arranged about the rotational axis and coupled to the hub for co-rotation therewith, wherein each blade includes a pressure surface, a suction surface opposite the pressure surface, a leading edge defining a boundary between the suction surface and the pressure surface, and a trailing edge opposite the leading edge, and a screen coupled to the hub and the blades for co-rotation therewith;
- wherein the hub, the blades, and the screen are integrally formed as a single piece, and wherein the plurality of blades comprises a plurality of main blades and a plurality of splitter blades, and wherein the leading edge of each main blade is integral with the hub and wherein the leading edge of each splitter blade is spaced from the hub.
11. (canceled)
12. The engine of claim 10, wherein each of the blades defines
- a nose-tail line connecting the leading edge and the trailing edge, the nose-tail line being a straight line and defining a length; and
- a mean line half-way between the pressure surface and the suction surface and intersecting the nose-tail line at the leading edge and the trailing edge.
13. (canceled)
14. The engine of claim 12, wherein each blade includes a camber between about 0.1 and about 0.2.
15. The engine of claim 14, wherein the plurality of blades comprises a plurality of main blades and a plurality of splitter blades, wherein the camber of the splitter blades is the same as the camber of the main blades.
16. The engine of claim 10, wherein the main blades and the splitter blades are alternately spaced about the rotational axis.
17. The engine of claim 10, wherein the screen includes a plurality of concentric rings coaxial with the rotational axis and interconnected by the blades.
18. The engine of claim 10, wherein each of the blades includes at least one notch in a top edge of the blade, the notch configured to allow an airflow to pass between adjacent blades.
19. The engine of claim 10, wherein each of the blades includes a top edge attached to the screen and a bottom edge, and wherein the bottom edge of each of the blades is a free edge.
20. The engine of claim 19, wherein the bottom edge includes a thickness less than that of the top edge.
Type: Application
Filed: Aug 23, 2012
Publication Date: Feb 27, 2014
Applicant: BRIGGS & STRATTON CORPORATION (Wauwatosa, WI)
Inventor: Elliot J. Matel (Milwaukee, WI)
Application Number: 13/593,153
International Classification: F04D 17/16 (20060101); F01P 1/06 (20060101);