Abstract:
An electronic system includes a component that heats up during operation and an acoustic dampening air moving assembly. The acoustic dampening air moving assembly includes air moving blades, a motor, a support structure and a housing. The motor is attached to the air moving blades to rotate the air moving blades. The support structure supports the motor and the air moving blades within the housing. The housing and the support structure at least partially include a material selected for its acoustic dampening characteristics. The acoustic dampening air moving assembly moves air to the component to cool the component. The selected material dampens acoustic vibrations within the electronic system.

Description:
BACKGROUND 
     Various types of electronic systems, such as computerized devices, emit noise. A common cause of such noise emission includes the workings of any moving parts within the electronic system. For example, the generation of air movement for cooling purposes involves the operation of air movers, such as fans and blowers. The air mover typically has a relatively fast rotating motor and blades. The motion of the motor and blades sets up acoustic vibrations in the air, as well as in the structures, within the electronic system. 
     Such noise can be, at best, simply annoying or, at worst, actually harmful to persons or devices that are within the vicinity of the electronic systems. Structural vibrations, for instance, may cause components to become disconnected or weakened within the electronic system or in nearby structures. Additionally, airborne acoustic vibrations may create a loud, noisy work environment, which can unduly stress nearby workers. The potentially deleterious effects of the noise may be particularly severe if several of the electronic systems are housed within the same confined space, thereby combining the acoustic vibrations of several noise sources. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary electronic system incorporating an embodiment of the present invention. 
         FIG. 2  is a perspective view of a portion of an alternative electronic system incorporating an embodiment of the present invention. 
         FIG. 3  is a perspective view of a portion of an exemplary air mover for use in the exemplary electronic system shown in  FIG. 1  according to an embodiment of the present invention. 
         FIG. 4  is a front view of the exemplary air mover shown in  FIG. 3  according to an embodiment of the present invention. 
         FIG. 5  is a perspective view of a portion of an alternative exemplary air mover for use in the exemplary electronic system shown in  FIG. 2  according to an embodiment of the present invention. 
         FIG. 6  is a cross section view taken along section lines  6 - 6  of the exemplary air mover shown in  FIG. 5  according to an embodiment of the present invention. 
         FIG. 7  is a cross section view of an alternative form of the exemplary air mover shown in  FIG. 5  according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary electronic system  100  incorporating an embodiment of the present invention is shown in  FIG. 1  with an exemplary acoustic dampening air moving assembly as described below. For purposes of this description, the electronic system  100  is shown as a computer system. The electronic system  100 , however, may be any appropriate electronic device (e.g. a computer server, a rack-based computerized device, a DVD player/recorder, a television, etc.) having some or all of the features and functions described herein. For this example, the electronic system  100  generally includes an optional display  102 , an optional keyboard  104  and a computer housing  106  connected together by cables  108  and  110 . The interior of the housing  106  generally contains various combinations of electrical and mechanical components, such as one or more air movers (e.g. an axial fan)  112 , one or more air movement guides  114  and one or more heat generating components  116 . Additionally, the interior of the housing  106  may contain a variety of other electrical and mechanical components, such as a system printed circuit board (PCB)  118 , internal wall-like components (e.g. cages, add-in cards and/or additional PCBs)  120  and relatively large block components (e.g. power supplies, hard drives, removable media drives, etc.)  122 . 
     Another exemplary electronic system  124  incorporating another embodiment of the present invention is shown in  FIG. 2  with an alternative exemplary acoustic dampening air moving assembly as described below. For purposes of this description, the electronic system  124  is also depicted as a computer system, but only a housing  126  is shown. As with the electronic system  100 , the electronic system  124  may be any appropriate electronic device (e.g. a computer server, a rack-based computerized device, a DVD player/recorder, a television, etc.) having some or all of the features and functions described herein. For this example, the interior of the housing  126  generally contains various combinations of electrical and mechanical components, such as one or more air movers (e.g. a centrifugal blower)  128 , one or more air movement guides  130  and one or more of the heat generating components  116 . Additionally, the interior of the housing  126  may contain a variety of other electrical and mechanical components, such as the system PCB  118 , the internal wall-like components  120  and the relatively large block components  122 . 
     In these examples, the internal wall-like components  120  and the relatively large block components  122  are exemplary only. There may be any number (including zero) of these components  120  and/or  122  having any size and/or shape placed in any location within the housing  106  or  126 . These components  120  and  122  are included herein merely to illustrate examples of obstructions within the housing  106  or  126 . 
     In these examples, the heat generating components  116  are placed at any appropriate location within the housing  106  or  126 , where the heat generating components  116  can operate according to a desired function for the electronic system  100  or  124 . For example, the heat generating components  116  may be placed on the system PCB  118  (as shown), in the block component  122  or on the wall-like component  120 . In this manner, the heat generating components  116  may interconnect and interoperate with other electronic or mechanical components of the electronic system  100  or  124 . 
     In these examples, the air mover  112  or  128  is placed at any appropriate location within the housing  106  or  126 , such as at an opening in a back wall  132  of the housing  106  or  126 . In this position, operation of the air mover  112  or  128  causes air to flow into the housing  106  or  126  (e.g. through the opening in the back wall  132 ) and out an appropriate other opening (e.g. through vents  134  in a front wall  136 ) of the housing  106  or  126 . 
     In these examples, heat generated by the components  116  is dissipated in order to maintain proper or optimum operation of the heat generating components  116  and of the electronic system  100  or  124 . Therefore, the airflow from the air mover  112  or  128  is preferably directed to the heat generating components  116  for cooling purposes. If the air mover  112  or  128  cannot force the airflow directly onto the heat generating components  116 , then one or more of the air movement guides  114  or  130  is used to deflect or guide the airflow to the heat generating components  116 . In other words, if the block components  122  and/or the wall-like components  120  restrict the placement of the air mover  112  or  128  or undesirably affect the direction of the airflow, then one or more of the air movement guides  114  and/or  130  is placed in the housing  106  or  126  to remedy the condition. 
     The air movement guide  114  ( FIG. 1 ) is illustrated as a curved wall placed near the air mover  112  that deflects airflow from the air mover  112  around the block component  122 , away from the wall-like component  120  and generally toward the heat generating components  116 . The air movement guide  130  ( FIG. 2 ), on the other hand, is illustrated as a duct connected to an outlet of the air mover  128  through which the airflow passes directly from the air mover  128  to an outlet positioned adjacent the heat generating components  116 . In other embodiments of the present invention, the air movement guide may be any appropriate duct, wall, baffle, or other device that affects the direction of airflow. Additional embodiments may include any appropriate combination and number of air movement guides. 
     In the example illustrated in  FIG. 1 , the air mover  112  and the air movement guide  114  comprise an “acoustic dampening air moving assembly” as described herein. Likewise, in  FIG. 2 , the air mover  128  and the air movement guide  130  comprise an “acoustic dampening air moving assembly.” In a situation in which no air movement guide (e.g.  114  or  130 ) is needed, then the air mover  112  or  128  alone may comprise the acoustic dampening air moving assembly. The air mover  112 , as shown in the embodiment of  FIGS. 1 ,  3  and  4 , is depicted as an axial fan. The air mover  128 , as shown in the embodiment of FIGS.  2  and  5 - 7 , is depicted as a centrifugal blower. Other embodiments may incorporate other types of air movers. As a result, various embodiments of the acoustic dampening air moving assembly may include any appropriate combination of one or more air mover and one or more (or none) air movement guide. 
     To dampen acoustic vibrations, materials for the air movement guide  114  or  130  and at least portions of the air mover  112  or  128  are selected for their acoustic dampening characteristics. Such materials are known as acoustic foams, sound deadening foams, noise canceling substances, noise or sound absorbing materials and acoustic/sound barriers, among other names. Additionally, the material may be reinforced, rigid, semi-rigid or flexible as needed or available for different applications. The acoustic dampening characteristics may be the primary criteria for selecting the material. Other selection criteria may include cost of the material, ease of working with the material and/or structural strength of the material (e.g. when the material must also provide structural support), among other criteria. 
     The exemplary air mover  112 , as shown in  FIGS. 3 and 4 , generally includes an air mover housing  138 , a support structure  140 , air moving blades  142  and a motor  144 . (The air moving blades  142  and the motor  144  are not shown in  FIG. 3  for clarity of showing the housing  138  and support structure  140 .) The support structure  140  generally has an outer cylinder portion  146  with struts  148  at one end to hold a motor mount portion  150 . The housing  138  generally surrounds the support structure  140  at the outer cylinder portion  146  and provides a means to attach the air mover  112  into the housing  106  of the electronic system  100 . The air moving blades  142  and motor  144  form an assembly that is mounted axially to the motor mount portion  150 , so the motor  144  can spin the air moving blades  142  within the outer cylinder portion  146  of the support structure  140 . 
     The air mover housing  138  and the support structure  140  are made of the materials selected for their acoustic dampening characteristics with a sufficient thickness to provide a desired amount of acoustic dampening and structural strength. In some embodiments, the air mover housing  138  and the support structure  140  are made of the same material. Some forms of this material, however, can be relatively flexible. Therefore, in other embodiments, the support structure  140  is made of material that is partially selected for its acoustic dampening characteristics and partially selected for its structural strength or may be structurally reinforced. In other words, in such embodiments, the support structure  140  has greater rigidity (if necessary) than the housing  138 . In this manner, the support structure  140  provides a firm support for the air moving blades  142  and the motor  144  and will not unduly flex in response to air pressure differentials generated by the spinning air moving blades  142 . (Alternatively, only the struts  148  and the motor mount portion  150  of the support structure  140  are structurally reinforced or are made of the acoustic dampening material that is partially selected for it structural strength, and the outer cylinder portion  146  is not reinforced or is made of material selected more for its acoustic dampening characteristics.) Additionally, separate components of the housing  138  and the support structure  140  may be attached together using adhesive methods, a heating method, a molding technique or other appropriate techniques. 
     The exemplary air mover  128 , as shown in  FIGS. 5 and 6 , generally includes an air mover housing  152 , an axial mount  154 , air moving blades  156  and a motor  158 . (The air moving blades  156  and the motor  158  are not shown in  FIG. 5  for clarity of showing the housing  152  and the axial mount  154 .) The air moving blades  156  and the motor  158  are axially mounted within the housing  152  at the axial mount  154 , so the motor  158  can spin the air moving blades  156  within the housing  152 . The housing  152  generally surrounds the air moving blades  156  and the motor  158  and provides a means to attach the air mover  128  into the housing  126  of the electronic system  124  ( FIG. 2 ). The spinning air moving blades  156  draw air (direction of arrows A) into the housing  152  at an inlet opening  160  in a side of the housing  152  and force the air out (direction of arrows B) of the housing  152  at an outlet opening  162 . 
     The air mover housing  152  is made of the materials selected for their acoustic dampening characteristics with a sufficient thickness to provide a desired amount of acoustic dampening and structural strength. In some alternative embodiments, however, as shown in  FIG. 7 , portions of an alternative housing  162  (e.g. central portions  164  and  166  of sidewalls  168  and  170  of the housing  162 ) are made of material that is partially selected for its acoustic dampening characteristics and partially selected for its structural strength or may be structurally reinforced. Thus, the central portions  164  and  166  have greater rigidity (if necessary) than the remainder of the housing  152 . In this manner, the central portion  164  provides a firm support for the axial mount  154 , the air moving blades  156  and the motor  158 . Also, the central portions  164  and  166  will not unduly flex in response to air pressure differentials generated by the spinning air moving blades  156 . Additionally, separate components of the housing  152  or  162 , the axial mount  154  and the central portions  164  and  166  may be attached together using adhesive methods, a heating method, a molding technique or other appropriate techniques. 
     Structural acoustic vibrations (i.e. vibrations transferred between solid objects) caused by the air mover  112  are generally dampened by the housing  138  and the support structure  140 . Similarly, structural acoustic vibrations caused by the air mover  128  are generally dampened by the housing  152  or  162 , with or without the more rigid central portions  164  and  166 . Airborne acoustic vibrations within the housing  106  or  126  of the electronic system  100  or  124  are absorbed by the acoustic dampening material of the air movement guides  114  or  130 , as well as by that of the air movers  112  or  128 . 
     Additionally, the acoustic dampening material described herein is typically of a lighter weight than the plastics and metals used in other air movers and air movement guides. Therefore, in addition to being able to dampen acoustic emissions, some embodiments of the acoustic dampening air moving assemblies described above are also more lightweight than other air movers and air movement guides.