Patent Publication Number: US-2021170833-A1

Title: Debris shield for an air conditioner unit

Description:
FIELD OF THE INVENTION 
     The present subject matter relates generally to air conditioners in recreational vehicles, and more particularly, to debris shields for preventing outside debris from passing into an indoor portion of the air conditioner unit. 
     BACKGROUND OF THE INVENTION 
     Certain recreational vehicles include an air conditioning system, referred to generally as a recreational vehicle air conditioner (RVAC), for maintaining a comfortable temperature within the passenger compartment. The air conditioning units are typically mounted on the roof or another exterior location of the recreational vehicle and utilize a sealed system for circulation refrigerant between an indoor and outdoor heat exchanger to facilitate heat transfer. For example, the indoor heat exchanger is positioned within an indoor portion of the RVAC and is in fluid communication with the passenger compartment through an opening in the roof. The outdoor heat exchanger is positioned within the outdoor portion and is separated from the indoor heat exchanger by a partition or divider. 
     Conventional RVACs include an indoor fan or blower for circulating a flow of air through the indoor heat exchanger. It is common to mount the motor for driving the indoor blower in the outdoor portion, e.g., to reduce noise within the passenger compartment. However, mounting the motor outside requires that a drive shaft pass through the partition that divides the indoor portion from the outdoor portion, introducing an air leak point and a path through which debris may enter the indoor portion. In this regard, when the indoor blower is operating and thus generating a negative pressure within the indoor portion, debris may tend to be drawn into the indoor portion through the hole in the partition. 
     Accordingly, an improved air conditioner unit would be useful. More specifically, a recreational vehicle air conditioner with an indoor blower driven by an outdoor motor and features for reducing the intake of debris or contaminants into the indoor portion would be particularly beneficial. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention. 
     In accordance with one exemplary embodiment of the present disclosure, a recreational vehicle air conditioner is provided including an indoor cover defining an indoor air plenum, an outdoor air plenum, and a shaft aperture. An indoor fan is positioned within the indoor air plenum for urging a flow of indoor air through the indoor air plenum, a drive shaft is mechanically coupled to the indoor fan and passing through the shaft aperture into the outdoor air plenum, a drive motor is mechanically coupled to the drive shaft for selectively rotating the indoor fan, and a debris shield is positioned around the drive shaft for blocking debris from passing through the shaft aperture. 
     In accordance with another exemplary embodiment of the present disclosure, a fan assembly for an air conditioner unit is provided. The air conditioner unit includes an indoor cover defining an indoor air plenum, an outdoor air plenum, and a shaft aperture. The fan assembly includes an indoor fan positioned within the indoor air plenum for urging a flow of indoor air through the indoor air plenum, a drive shaft mechanically coupled to the indoor fan and passing through the shaft aperture into the outdoor air plenum, and a debris shield positioned around the drive shaft for blocking debris from passing through the shaft aperture. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures. 
         FIG. 1  provides a perspective view of a recreational vehicle according to an exemplary embodiment of the present disclosure. 
         FIG. 2  provides a perspective view of a recreational vehicle air conditioner (RVAC) that may be used with the exemplary recreational vehicle of  FIG. 1 , with an outdoor cover removed for clarity. 
         FIG. 3  provides a perspective view of the exemplary RVAC of  FIG. 2  with an indoor cover removed for clarity. 
         FIG. 4  provides a top view of the exemplary RVAC of  FIG. 2  with an indoor cover removed for clarity. 
         FIG. 5  provides a schematic view of an air conditioning system according to an exemplary embodiment of the present disclosure. 
         FIG. 6  provides a schematic side view of the exemplary RVAC of  FIG. 2 . 
         FIG. 7  provides a schematic cross-sectional view of a drive shaft and debris shield according to an exemplary embodiment of the present subject matter. 
     
    
    
     Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention. 
     DETAILED DESCRIPTION 
     Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
     In order to aid understanding of this disclosure, several terms are defined below. The defined terms are understood to have meanings commonly recognized by persons of ordinary skill in the arts relevant to the present invention. The terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). The terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. In addition, as used herein, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent margin of error. 
       FIG. 1  provides a perspective view of an exemplary recreational vehicle  100  in accordance with the present disclosure. People may employ recreational vehicle  100  for a variety of purposes, including transportation, cooking, eating, sleeping, entertaining, and the like. As such, recreational vehicle  100  defines a passenger compartment  102 , which may further include a bed, stove, table, restroom, or multiple compartments for storing items that passengers wish to take with them on their travels. Because people often spend significant time within the passenger compartment of recreational vehicle  100 , climate control of the passenger compartment is desirable. 
     Accordingly, an air conditioning system  104  may be mounted on recreational vehicle  100  to provide cooled air to the passenger compartment. Air conditioning system  104  is typically mounted to an outside surface  106  of recreational vehicle  100 . This arrangement is desirable because a byproduct of operation of air conditioning system  104  is heated air, which has been passed over a heat exchanger to remove heat from the air circulating within passenger compartment  102 . During certain operations, this heated air may be exhausted to the ambient air. As shown in the exemplary embodiment of  FIG. 1 , air conditioning system  104  may be mounted on an outer surface  106 , such as the ceiling or top of recreational vehicle  100 . Also as shown in  FIG. 1 , air conditioning system  104  may include a top cover or outer grill  108  that is positioned over the working components air conditioning system  104 , e.g., to protect such working components from rain, wind, debris, etc. 
     Referring now generally to  FIGS. 2 through 6 , the operation of air conditioning system  104  will be described in more detail according to exemplary embodiments of the present subject matter. As illustrated, outer grill  108  has been removed to reveal working components of air conditioning system  104 . Air conditioning system  104  generally includes an indoor bulkhead for indoor cover  110  that divides air conditioning system  104  between an indoor and outdoor portion, such as in a packaged terminal air conditioner unit (PTAC) or a split heat pump system. Specifically, indoor cover  110  defines and indoor air plenum  112  and an outdoor air plenum  114 . In this regard, as shown in  FIGS. 2 and 6 , indoor cover  110  generally shields the indoor components of air conditioning system  104  from the outdoor environment  116 . As shown in  FIGS. 3 and 4 , indoor cover  110  is removed to reveal additional working components of air conditioning system  104 , each of which will be described below in detail. 
     Referring now generally to  FIGS. 2 through 6 , relevant components of air conditioning system  104  will be described. It will be understood that air conditioning system  104  includes various heat pump components, such as a sealed system, for treating air within an interior of an associated recreational vehicle  100 . Such components are well understood by those skilled in the art and a description of such components is omitted for the sake of brevity. In this regard, for example, air conditioning system  104  includes refrigerant circulating between evaporator  120 , compressor  122 , condenser  124 , and expansion device  126 , as shown in the refrigeration loop  128  of air conditioning system  104  in  FIG. 2 . Refrigerant, also known as coolant, carries heat from the passenger compartment  102  of recreational vehicle  100  to the outdoors  116  (e.g., ambient area surrounding outer surface  106  of the passenger compartment  102 ). Refrigerant is useful because it changes states from a liquid to a vapor at convenient temperatures for a refrigeration cycle. One suitable refrigerant for use in refrigeration loop  128  is 1,1,1,2-Tetrafluoroethane, also known as R-134A, although it should be understood that the present disclosure is not limited to such example and that any suitable refrigerant may be utilized. 
     The refrigerant begins by passing through evaporator  120  in liquid form. Ambient air or air from the passenger compartment  102  may pass over evaporator  120 , e.g., as motivated by an evaporator air handler. More specifically, as illustrated, air conditioner system  104  may include an indoor fan  130  configured for urging a flow of indoor air (e.g., as identified by reference numeral  132  in  FIG. 6 ). Because the liquid refrigerant is cold in this low-pressure state, it absorbs heat from the air passed over it, cooling the air for delivery to the passenger compartment  102 . As the liquid refrigerant absorbs heat, it evaporates into a vapor. From there, the gaseous refrigerant is delivered to compressor  122 , which increases the pressure of the refrigerant, thus raising its temperature well-above the ambient temperature outside of recreational vehicle  100 . From compressor  122 , the heated refrigerant is delivered to condenser  124 . Air may pass over condenser  124 , e.g., as motivated from a condenser air handler. More specifically, as illustrated, air conditioning system  104  may include an outdoor fan  134  configured for urging a flow of outdoor air (e.g., as identified by reference numeral  136  in  FIG. 6 ), thereby facilitating heat transfer from the heated refrigerant to the ambient air. In releasing this heat energy, the refrigerant condenses back into liquid form. Next, the refrigerant is delivered to expansion device  126 , where the pressure of the refrigerant is reduced, thus decreasing its temperature. The cooled, liquid refrigerant is then delivered back to evaporator  120  to repeat the process. 
     In order to transport cooled air from the air conditioning system  104  on an outside surface  106  of recreational vehicle  100  to the passenger compartment  102  on the inside of recreational vehicle  100 , outer surface  106  may define an opening  140  that is in fluid communication with indoor air plenum  112 . In addition, air conditioning system  104  may include a ceiling-mount cover panel  142  that may be mounted on a ceiling within an interior of an associated recreational vehicle. Cover panel  142  may overlay and hide components of air conditioning system  104  to provide a pleasant cosmetic appearance for air conditioning system  104 . Cover panel  142  may also include perforated sections to allow the flow of outdoor air  132  through cover panel  142 . 
     For example, cover panel  142  may include an air inlet  144  and an air outlet  146 . Air inlet and outlets  144 ,  146  may be separate from each other on cover panel  142 . Air from within the interior of the associated recreational vehicle may flow through cover panel  142  via air inlet  144 , and such air may be treated (e.g., heated or cooled) by a sealed system of air conditioning system  104 , and the treated air may then flow back into the interior of the associated recreational vehicle through cover panel  142  via air outlet  146 . Cover panel  142  may also include a removable filter cover (not shown) mounted to cover panel  142  and being perforated to allow air flow through the filter cover. For example, the filter cover may support or hold a filter medium, such as a concertinaed or pleated fabric filter, fiberglass filter, etc., that filters air entering air conditioning system  104  at air inlet  144 . 
     As shown, indoor fan  130  is positioned within indoor air plenum  112 , e.g., adjacent a vertical bulkhead  150  which is part of indoor cover  110 . According to the illustrated embodiment, a fan drive motor  152  is positioned outside of indoor air plenum  112 , e.g., within outdoor air plenum  114 . This may be advantageous, for example, to cool drive motor  152  by permitting the flow of outdoor air  136  to pass over drive motor  152 , to reduce noise within passenger compartment  102 , or for a variety of other reasons. Notably, however, mounting drive motor  152  outside of indoor air plenum  112  requires a drive shaft  154  to pass through indoor cover  110  in order to mechanically coupled with indoor fan  130 . 
     Specifically, according to the illustrated embodiment, indoor cover  110 , or more specifically vertical bulkhead  150  defines a shaft aperture  156  through which drive shaft  154  may pass from outdoor air plenum  114  into indoor air plenum  112 . Specifically, drive shaft  154  mechanically couples drive motor  152  which is positioned in outdoor air plenum  114  with indoor fan  130  which is positioned within indoor air plenum  112 . Notably, however, shaft aperture  156  may provide a passageway through which outdoor debris or unconditioned air may enter into indoor air plenum  112 . In this regard, specifically when indoor fan  130  is operating and creating a negative pressure within indoor air plenum  112 , dirt and debris may have a tendency to be drawn into indoor air plenum  112 . Aspects of the present subject matter are directed towards features for reducing or eliminating the passage of such debris into indoor air plenum  112 . 
     Specifically, according to exemplary embodiments, air conditioning system  104  may include a debris shield  160  that is positioned around the drive shaft  154  for blocking debris from passing through shaft aperture  156 . Debris shield  160  may generally be any suitable device or structure that has a tendency to block shaft aperture  156  for preventing the flow of debris into indoor air plenum  112 . For example, according to the exemplary embodiment illustrated in  FIG. 6 , debris shield  160  may be an annular disc or washer  162 . According to alternative embodiments, debris shield  160  may have any other suitable size, shape, geometry, position, and configuration. For example, according to the exemplary embodiment illustrated in  FIG. 7 , debris shield  160  is a conical washer  164  that tapers from a wide end  166  toward a narrow end  168 . Specifically, as illustrated, wide end  166  is positioned adjacent indoor cover  110  or over shaft aperture  156 , while narrow end  168  extends toward drive motor  152 . 
     Debris shield  160  may be constructed from any suitable material or combination of materials. For example, according to exemplary embodiments, debris shield  160  is made from rubber. According to alternative embodiments, debris shield  160  may be made from a polymer material, plastics, metals, fabrics, or any other suitable material or composition. In addition, although debris shield  160  is illustrated as having a substantially smooth surface, it should be appreciated that debris shield  160  may further include surface features such as ridges or bumps for facilitating debris removal, shedding, or movement. Other debris shields  160  are possible and within scope of the present subject matter. 
     According to the illustrated embodiment, debris shield  160  is mounted within outdoor air plenum  114 , e.g., directly to drive shaft  154  such that it rotates with drive shaft  154 . However, it should be appreciated that according to alternative embodiments, debris shield  160  may alternatively be mounted directly to indoor cover  110 , e.g., such that it does not rotate with drive shaft  154 . According to the illustrated embodiment, drive shaft  154  extends substantially along a horizontal direction H and is operably coupled to both indoor fan  130  and outdoor fan  134 . In this regard, drive motor  152  may be positioned between the indoor fan  130  and outdoor fan  134  for selectively rotating both during an operating cycle of air conditioning system  104 . It should be appreciated that according to alternative embodiments, outdoor fan  134  may include a dedicated motor. It should be further appreciated that air conditioning system  104  and refrigeration loop  128  may include additional or alternative components for facilitating a heating or cooling cycle. 
     According to exemplary embodiments, drive shaft  154  and/or debris shield  160  may include features for positioning debris shield  160  at the desired location or locking debris shield  160  in a particular position. For example, as best shown in  FIG. 7 , drive shaft  154  may define a locating groove  170  that is configured for receiving a portion of debris shield  160  to locate debris shield  160  at the desired axial location along drive shaft  154 . In addition, a locking mechanism  172  may be mounted to drive shaft  154  for locking debris shield  160  in position. Specifically, according to the illustrated embodiment, locking mechanism  172  is a clip  174  that snaps into a locking groove  176  defined on drive shaft  154 . It should be appreciated that any other suitable locking mechanism  172  may be used according to alternative embodiments. For example, locking mechanism  172  may include a lock washer, a set screw, a clamping member, or any other suitable locking mechanism or device. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.