The present disclosure relates generally to a fan hub, and, more particularly, to an apparatus for stiffening a fan hub by partially or completely filling the gap between the fan hub plates.
Fans are used in industry in a multitude of applications, including in radiators for cooling engines used in on road and off road vehicles. A fan may include blades and a hub used to hold the blades.
Fan blades may be made of metal or composite materials, and generally have the same size and shape (i.e., come from the same mold) in each fan. The number of blades per fan can be changed though hub machining changes. The diameter of the fan can also be changed by increasing the diameter of the fan hub.
The fan hub generally comprises two plates separated by a central hub connection, sometimes referred to as a spacer. The fan blades may be bolted to both plates of the hub. The plates are spaced apart to accommodate the roots of the blades, and so a gap may exist between the hub plates that runs from the central hub connection to the perimeter (outer diameter) of the hub.
The stiffness of such fan hubs may be lower than desired due to the spaced apart, two plate design. This low stiffness can result in a low frequency fore-aft bending mode that causes high stresses in multiple locations on the hub plates. The overall stiffness becomes even lower as the hub diameter is increased.
It is known to provide an annular plate located between two adjacent hub plates. For example, U.K. Patent Publication No. GB 2390647B describes an axial flow impeller having an annular plate located between two hub plates and having spring tags for improving the location of the blades with respect to the hub. While effective for its intended purpose, the annular plate is not designed to, and does not necessarily, stiffen the hub.
The present disclosure presents an apparatus for stiffening a fan hub and thus reducing hub stresses. While a number of exemplary configurations are described herein, it should be appreciated that the examples are not a limitation on the scope of this disclosure or of the attached claims except to the extent expressly noted.
According to an aspect of the disclosure, a fan hub is provided comprising a front plate, a rear plate, an annular central hub connection and a stiffener. The front plate comprises an inner facing surface and an outer facing surface, and has a diameter and a perimeter. Likewise, the rear plate comprises an inner facing surface and an outer facing surface and has a diameter and a perimeter. The front plate and the rear plate each define a central bore, a plurality of sets of blade fastener apertures arranged circumferentially around the plate near the plate perimeter, a plurality of central hub connection fastener apertures arranged circumferentially around the central bore, and a plurality of stiffener fastener apertures. The central bore, the blade fastener apertures, the central hub connection fastener apertures and the stiffener fastener apertures of the rear plate register with the central bore, the blade fastener apertures, the central hub connection fastener apertures and the stiffener fastener apertures of the front plate. The central hub connection defines an inner bore which registers with the central bores of the front plate and the rear plate. The central hub connection has a cylindrical outer wall and further defines central hub connection apertures registering with the central hub connection fastener apertures of the front plate and the rear plate. The stiffener occupies a gap between the front plate and the rear plate and may comprise a body and a plurality of arms extending radially outward from a perimeter of the body. The body defines a stiffener central bore registering with central bores of the front plate and the rear plate. The stiffener has an outer diameter no larger than the diameter of the front plate. Each arm extends radially outward from the body and between adjacent sets of blade fastener apertures. The stiffener defines apertures for receiving fasteners. The stiffener apertures register with some or all of the stiffener fastener apertures in the front plate and the rear plate.
According to another aspect of the disclosure, a fan is provided comprising a fan hub and fan blades. The fan hub comprises a front plate, a rear plate, an annular central hub connection and a stiffener. The front plate comprises an inner facing surface and an outer facing surface, and has a diameter and a perimeter. Likewise, the rear plate comprises an inner facing surface and an outer facing surface and has a diameter and a perimeter. The front plate and the rear plate each define a central bore, a plurality of sets of blade fastener apertures arranged circumferentially around the plate near the plate perimeter, a plurality of central hub connection fastener apertures arranged circumferentially around the central bore, and a plurality of stiffener fastener apertures. The central bore, the blade fastener apertures, the central hub connection fastener apertures and the stiffener fastener apertures of the rear plate register with the central bore, the blade fastener apertures, the central hub connection fastener apertures and the stiffener fastener apertures of the front plate. The central hub connection defines an inner bore which registers with the central bores of the front plate and the rear plate. The central hub connection has a cylindrical outer wall and further defines central hub connection apertures registering with the central hub connection fastener apertures of the front plate and the rear plate. The stiffener comprises a body and a plurality of arms extending radially outward from a perimeter of the body. The body defines a stiffener central bore registering with central bores of the front plate and the rear plate. The stiffener has an outer diameter no larger than the diameter of the front plate. Each arm extends radially outward from the body and between adjacent sets of blade fastener apertures. The stiffener defines apertures for receiving fasteners. The stiffener apertures register with some or all of the stiffener fastener apertures in the front plate and the rear plate. The fan blades are affixed to the fan hub, with each blade comprising an inner portion located between the front plate and the rear plate.
In still another aspect of the disclosure, a machine is provided comprising a cooling system having a fan. The fan comprising a fan hub and fan blades. The fan hub comprises a front plate, a rear plate, an annular central hub connection and a stiffener. The front plate comprises an inner facing surface and an outer facing surface, and has a diameter and a perimeter. Likewise, the rear plate comprises an inner facing surface and an outer facing surface and has a diameter and a perimeter. The front plate and the rear plate each define a central bore, a plurality of sets of blade fastener apertures arranged circumferentially around the plate near the plate perimeter, a plurality of central hub connection fastener apertures arranged circumferentially around the central bore, and a plurality of stiffener fastener apertures. The central bore, the blade fastener apertures, the central hub connection fastener apertures and the stiffener fastener apertures of the rear plate register with the central bore, the blade fastener apertures, the central hub connection fastener apertures and the stiffener fastener apertures of the front plate. The central hub connection defines an inner bore which registers with the central bores of the front plate and the rear plate. The central hub connection has a cylindrical outer wall and further defines central hub connection apertures registering with the central hub connection fastener apertures of the front plate and the rear plate. The stiffener comprises a body and a plurality of arms extending radially outward from a perimeter of the body. The body defines a stiffener central bore registering with central bores of the front plate and the rear plate. The stiffener has an outer diameter no larger than the diameter of the front plate. Each arm extends radially outward from the body and between adjacent sets of blade fastener apertures. The stiffener defines apertures for receiving fasteners. The stiffener apertures register with some or all of the stiffener fastener apertures in the front plate and the rear plate. The fan blades are affixed to the fan hub, with each blade comprising an inner portion located between the front plate and the rear plate.
Other aspects and features of the disclosed systems and methods will be appreciated from reading the attached detailed description in conjunction with the included drawing figures. Moreover, selected aspects and features of one example embodiment may be combined with various selected aspects and features of other example embodiments.
For further understanding of the disclosed concepts and embodiments, reference may be made to the following detailed description, read in connection with the drawings, wherein like elements are numbered alike, and in which:
It is to be noted that the appended drawings illustrate only typical embodiments and are therefore not to be considered limiting with respect to the scope of the disclosure or claims. Rather, the concepts of the present disclosure may apply within other equally effective embodiments. Moreover, the drawings are not necessarily to scale, emphasis generally being placed upon illustrating the principles of certain embodiments.
An exemplary embodiment of a work machine 210 according to the present disclosure is shown in
The work machine 210 may include a plurality of ground-engaging elements 214, in this case wheels. As should be appreciated by one of ordinary skill in the art, an engine may provide propulsion power for the ground-engaging elements 214 and may power a variety of other machine systems, including various mechanical, electrical, and hydraulic systems and/or components. The work machine 210 may also include an operator control station 216 including a variety of operator controls and displays useful for operating the work machine 210 and/or a dump body 218 which may be pivotal relative to the machine frame 212.
The hub 12 may comprise a first or front plate 16, a second or rear plate 18 (obscured in
Each blade 14 may comprise a generally planar inner portion 42 configured to engage the hub 12, a generally curved distal portion 44 which may be angularly displaced from the plane of the hub 12, and an intermediate portion 46 which joins the inner portion 42 and the distal portion 44. The blade inner portion 42 may have an inner edge 52 and may define apertures 48 that align with the blade fastener apertures 30 in each plate 16, 18. Each blade 14 may be attached to the hub 12 and, more particularly, to the plates 16, 18 by any suitable means, such as rivets or bolts 40.
This gap 50 reduces fan hub stiffness, resulting in a low frequency fore-aft bending mode that causes high stresses in multiple locations on the plates 16, 18 close to the fan blades 14 and the central hub connection 20. The overall stiffness becomes even less as the hub diameter is increased.
The body 62 may define body apertures 70 for receiving fastening means such as bolts 40. Each arm 64 may define arm apertures 72 for receiving fastening means such as bolts 40. The body apertures 70 and arm apertures 72 may align axially with the stiffener fastener apertures 33 located in (defined by) each plate 16, 18.
The stiffener 60 may also define voids 74 throughout the body 62 and arms 64 to reduce weight while maintaining a satisfactory stiffness. The voids 74 may be any suitable size and shape, and may be oriented symmetrically about the stiffener central bore 68 to maintain an even distribution of the weight of the stiffener 60 about the bore 68.
The stiffener 60 may extend radially from the central hub connection 20 to the perimeter 26 of the front plate 16 and the rear plate 18. The stiffener body perimeter 66 may be located anywhere between a location near the central hub connection 20 to a location at or near the inner edges 52 of the blades 14. Each arm 64 may extend outwardly from the body 62 between the inner portions 42 of adjacent blades 14 to a location near or at the perimeter 26 of the front plate 16 and the rear plate 18.
The stiffener 60 may completely or partially occupy the gap 50 between the front plate 16 (not shown in
The stiffener 60 may abut the central hub connection 20, the front plate 16 and the rear plate 18. The stiffener 60 may also abut the inner portions 42 of the blades 14 or, as shown in
The stiffener 60 may be affixed to the front plate 16 and the rear plate 18 with fasteners such as bolts 40 or, more specifically, huck bolts. The stiffener 60 may be fastened to the front plate 16 and the rear plate 18 at different diametric (annular) locations about the central hub connection 20. For example, the stiffener 60 may be fastened to the front plate 16 and the rear plate 18 at the stiffener body 62 a short distance from the central hub connection 20 (where the stiffener body apertures 70 are located) and at the radially distal ends of the stiffener arms 64 near the perimeter 26 of the front plate 16 and the rear plate 18 (where the stiffener arm apertures 72 are located). The locations of the stiffener apertures 70, 72, and thus the fasteners 40, may be optimized to create a high level of hub stiffness and a low hub weight.
The stiffener 60 may be of unitary construction, that is, may be made of a single piece of material, or it may comprise multiple layers (thicknesses) of stiffener plates which can be stacked on top of one another so that the total axial thickness is substantially equal to the thickness of the gap 50 between the plates 16, 18. The stiffener 60 may be made of any suitable material, including steel.
The stiffener body 82 may define apertures 90 for receiving fastening means such as bolts 40. In addition, each arm 84 may define apertures 92 for receiving fastening means such as bolts 40. The apertures 90, 92 may align with the stiffener fastener apertures 33 located in (defined by) each plate 16, 18. The stiffener body 82 may be solid with the exception of the apertures 90. Alternatively, the stiffener body 82 and/or the stiffener arms 84 may define voids 94 to reduce weight while maintaining a satisfactory stiffness. The voids 94 may be any suitable size and shape, and may be oriented symmetrically about the body central bore 88 to evenly distribute the weight of the stiffener 80 about the bore 88.
The body 102 may define apertures 110 for receiving fastening means such as bolts 40. Each arm 104 may define apertures 112 for receiving fastening means such as bolts 40. The apertures 112 may align with stiffener fastener apertures 33 located in (defined by) each plate 16, 18. The stiffener 100 may also define voids 114 throughout the body 102 to reduce weight while maintaining a satisfactory stiffness. The voids 114 may be any suitable shape, and may be oriented symmetrically about the body central bore 108 to maintain an even distribution of the weight of the stiffener 100 about the bore 108.
The body 122 may define apertures 130 for receiving fastening means such as bolts 40. Each arm 124 may define apertures 132 for receiving fastening means such as bolts 40. The apertures 132 may align with stiffener fastener apertures 33 located in (defined by) each plate 16, 18. The apertures 130, 132 may be arranged in one, two or more concentric circular arrays centered around the central bore 128.
In general, the teachings of the present disclosure may find broad applicability in many industries including, but not limited to, construction, agriculture, and road maintenance industries. More specifically, the present disclosure may find applicability in any industry using machines or equipment that include a fan based cooling system.
Referring to
While the present disclosure has shown and described details of exemplary embodiments, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the disclosure as defined by claims supported by the written description and drawings. Further, where these exemplary embodiments (and other related derivations) are described with reference to a certain number of elements it will be understood that other exemplary embodiments may be practiced utilizing either less than or more than the certain number of elements.