Abstract:
Disclosed is an anti-rattle valve feature for a heating, ventilating, and air conditioning assembly. In a typical HVAC assembly each end of an air valve shaft is received in a pivot hole permitting the air valve shaft to rotate within the assembly. Because the inside diameter of the pivot holes are larger than the outside diameter of the ends of the air valve shaft, the air valve shaft may rattle within the pivot holes. Disclosed is a finger that contacts the air valve shaft to apply pressure to the air valve shaft and biases an end of the air valve shaft against the inside of it pivot hole, thereby preventing rattling of the air valve shaft within its respective pivot holes.

Description:
TECHNICAL FIELD  
         [0001]    The subject invention generally relates to a heating, ventilating, and air conditioning (HVAC) assembly for a motor vehicle. More specifically, the subject invention relates to a HVAC assembly that includes an anti-rattle valve feature to reduce the rattle noise generated by air valve shafts in the assembly.  
         BACKGROUND OF THE INVENTION  
         [0002]    HVAC assemblies are well known in the art and find common utilization in motor vehicles. Typically an HVAC assembly is used to distribute the output from the heater, air conditioning unit, and ventilation throughout the interior of, for example, a vehicle. The HVAC assembly is manipulated by an operator to direct the output in a plurality of manners. For example, it is common to be able to select between defrost, defrost and floor, dash, dash and floor, and floor outputs from the HVAC assembly in a vehicle. Within the HVAC assembly air is directed to an appropriate outlet via movement of an air valve, typically mounted on an air valve shaft. Rotation of the shaft, either manually or mechanically, rotates the valve relative to its respective outlet to control the amount of air exiting through the outlet associated with the valve. Typically, the ends of the air valve shaft are mounted into pivot holes in a housing of the HVAC assembly to allow for positioning and rotation of the air valve shaft.  
           [0003]    To provide for proper operation of the HVAC assembly it is important that the air valve shafts and thereby the air valves rotate with only slight resistance within the HVAC assembly. This is particularly true when mechanical means are utilized to alter the position of the air valves. To permit mounting of the air valve shafts within the housing of the HVAC assembly it is generally required that the pivot holes in the housing be larger in diameter than the pivot points at the ends of the shaft. Because of this manufacturing requirement it is possible for the air valve shafts to rattle in the pivot holes thus creating undesirable noise from the HVAC assembly. In the past others have used either greased foam pads or felt washers near the pivot points and within the pivot holes to reduce noise transmitted by rattling of the air valve shaft within the pivot hole. This solution, however, is unsatisfactory because it increases the cost and difficulty of manufacture of HVAC assemblies.  
           [0004]    Thus, it would be beneficial to design an HVAC assembly with an anti-rattle valve feature that would allow for a low cost solution to the problem of air shaft rattle within HVAC assemblies. Any solution must maintain the rotational freedom of the air valve shaft within the pivot hole.  
         SUMMARY OF THE INVENTION  
         [0005]    In a first embodiment, the present invention is a heating, ventilating, and air conditioning assembly comprising: a housing having a first pivot hole with an inside; an air valve shaft having a first pivot point, the first pivot point received in the first pivot hole and rotatable therein; and a finger, the finger contacting the shaft and biasing the first pivot point against the inside of the first pivot hole thereby reducing a rattle of the air valve shaft.  
           [0006]    In a second embodiment, the present invention is a heating, ventilating, and air conditioning assembly comprising: a housing having a first pivot hold with an inside and a second pivot hole with an inside; an air valve shaft having a first pivot point opposite a second pivot point, the first and second pivot points received in the first and second pivot holes, respectively, and rotatable therein; a first finger, the first finger contacting the shaft and biasing the first pivot point against the side of the first pivot hole; and a second finger, the second finger contacting the shaft and biasing the second pivot point against the inside of the second pivot hole, the first and second fingers reducing a rattle of the air valve shaft. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a schematic cutaway view of a HVAC assembly according to the present invention;  
         [0008]    [0008]FIG. 2 is a cross-sectional schematic view of an HVAC assembly according to the present invention; and  
         [0009]    [0009]FIG. 3 is a cross-sectional schematic view of an alternative HVAC assembly according to the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0010]    An HVAC assembly according to the present invention is shown generally at  20  in FIG. 1. HVAC assembly  20  includes a housing  22  and a plurality of outlets  24 ,  26 . Controlling airflow through each of the outlets  24 ,  26  is an air valve  28 ,  30 . Each air valve  28 ,  30  is mounted on an air valve shaft  32 ,  34 . Each air valve shaft  32 ,  34  includes a first pivot point  36  opposite a second pivot point  38 . The first pivot point  36  is received in a first pivot hole  40  of housing  22  and the second pivot point  38  is received in a second pivot hole  42  in housing  22 . As would be understood by one of ordinary skill in the art, the pivot holes  40 ,  42  can either be through holes as shown or blind holes depending on design considerations. In accordance with the present invention, at least one finger  44  is associated with each shaft  32 ,  34 . The fingers  44  contact the shaft  32 ,  34  and bias the pivot points  36 ,  38  against the inside of the respective pivot hole  40 ,  42 . The biasing force is sufficient to greatly reduce the rattle of the shafts  32 ,  34 , even if only a single finger  44  is used, but still allows for full and free rotation of the shafts  32 ,  34 . As shown, in some situations only as single finger  44  is used rather than a multiple of fingers  44 . If necessary, even more than two fingers  44  can be used on the same shaft  32 ,  34 . When only a single finger  44  is used it can sometimes be preferable to locate it centrally along the shaft  32 ,  34 .  
         [0011]    As discussed above, the first and second pivot holes,  40  and  42 , each have an inside diameter that is larger than the diameter of either the first pivot point  36  or the second pivot point  38 . This clearance permits the shaft  32 ,  34  to be mounted in the housing  22 .  
         [0012]    As shown in FIG. 2, a vehicle HVAC assembly  50  typically includes a housing  51  containing a number of components. FIG. 2 is a simplified and stylized schematic designed to illustrate the present invention in a simplified form for a vehicle. Typically, an evaporator  52  and a heater  54  are located within the assembly  50 . The assembly  50  is shown as having a defrost outlet  56 , a vent outlet  58 , and a floor outlet  60 .  
         [0013]    The defrost outlet  56  includes an air valve  62  mounted to an air valve shaft  64  that rotates the valve  62 . A pivot hole  66  is shown with a pivot point  68  located therein. As can be seen from the illustration, the inside diameter of the pivot hole  66  is larger than the outer diameter of the pivot point  68 . A finger  70  is formed integrally with the housing  51  and extends therefrom to contact shaft  64  of the air valve  62  associated with the defrost outlet  56 . As shown, the finger  70  contacts the shaft  64  and biases the pivot point  68  against the inside of the pivot hole  66 . The finger  70  is sufficiently flexible and resilient that during manufacture of the HVAC assembly  50  it can be flexed out of the way to allow insertion of the pivot point  68  into the pivot hole  66 . After insertion of the pivot point  68  the finger  70  springs back to contact the shaft  64 .  
         [0014]    The vent outlet  58  includes an air valve  72  mounted to an air valve shaft  74  that rotates the valve  72 . A pivot hole  76  is shown with a pivot point  78  located therein. As can be seen from the illustration, the inside diameter of the pivot hole  76  is larger than the outer diameter of the pivot point  78 . A finger  80  is formed integrally with the housing  51  and extends therefrom to contact shaft  74  of the air valve  72  associated with the vent outlet  58 . As shown, the finger  80  contacts the shaft  74  and biases the pivot point  78  against the inside of the pivot hole  76 . The finger  80  is sufficiently flexible and resilient that during manufacture of the HVAC assembly  50  it can be flexed out of the way to allow insertion of the pivot point  78  into the pivot hole  76 . After insertion of the pivot point  78  the finger  80  springs back to contact the shaft  74 .  
         [0015]    The floor outlet  60  includes an air valve  82  mounted to an air valve shaft  84  that rotates the valve  82 . A pivot hole  86  is shown with a pivot point  88  located therein. As can be seen from the illustration, the inside diameter of the pivot hole  86  is larger than the outer diameter of the pivot point  88 . A V-shaped finger  90  is formed integrally with the housing  51  and extends therefrom to contact shaft  84  of the air valve  82  associated with the floor vent  58 . The V-shaped finger  90  includes a first leg  92  attached to the housing  51  and a second leg  94  contacting the shaft  84 . As shown, the finger  90  biases the pivot point  88  against the inside of the pivot hole  86 . The finger  90  is sufficiently flexible and resilient that during manufacture of the HVAC assembly  50  it can be flexed out of the way to allow insertion of the pivot point  88  into the pivot hole  86 . After insertion of the pivot point  88  the finger  90  springs back to contact the shaft  84 . In this embodiment the finger  90  is the only finger used to bias the shaft  84 .  
         [0016]    In a preferred embodiment, the HVAC assembly  20 ,  50  includes a finger  44 ,  70 ,  80 ,  90  associated with each pivot point  36 ,  38 ,  68 ,  78 ,  88  of an air valve shaft  32 ,  34 ,  64 ,  74 ,  84 . Preferably, the fingers  44 ,  70 ,  80 ,  90  are each located closely adjacent to the pivot points  36 ,  38 ,  68 ,  78 ,  88  and the pivot holes  40 ,  42 ,  66 ,  76 ,  86  associated with each shaft  32 ,  34 ,  64 ,  74 ,  84 . Preferably the portion of the finger  44 ,  70 ,  80 ,  90  in contact with the shaft  32 ,  34 ,  64 ,  74 ,  84  has a width of from 1.5 to 15.0 millimeters and more preferably from 1.5 to 10.0 millimeters.  
         [0017]    In a preferred embodiment, the finger  44 ,  70 ,  80 ,  90  is formed from the same material as the housing  22 ,  51  typically a plastic material, such as, for example, an injection molded polypropylene with 20 to 40 percent talc. Preferably the finger  44 ,  70 ,  80 ,  90  is formed integrally with the housing  22 ,  51 , which is often a molded plastic part. In other embodiments, however, it is possible to form finger  44 ,  70 ,  80 ,  90  from materials other than those of the housing  22 ,  51  and then securing one end of the finger  44 ,  70 ,  80 ,  90  to the housing  22 ,  51  in manners known in the art. Such attachment could comprise an adhesive, an interlocking fit, or a friction fit. In a preferred embodiment, however, the finger  44 ,  70 ,  80 ,  90  is formed from the housing  22 ,  51  leading to greatly reduced costs for the present invention. The finger  44 ,  70 ,  80 ,  90  is a resiliently flexible finger  44 ,  70 ,  80 ,  90  thus permitting it to be flexed during manufacture of the HVAC assembly  20 ,  50 . After assembly the finger  44 ,  70 ,  80 ,  90  returns to its previous position and contacts the air valve shaft  32 ,  34 ,  64 ,  74 ,  84 . Finger  44 ,  70 ,  80 ,  90  applies force to the air valve shaft  32 ,  34 ,  64 ,  74 ,  84 . thereby forcing the pivot points  36 ,  38 ,  68 ,  78 ,  88  against the insides of the pivot holes  40 ,  42 ,  66 ,  76 ,  86 .  
         [0018]    [0018]FIG. 3 discloses another embodiment. The cross-sectional view is of an HVAC assembly frame  100  having an air valve shaft  102  located therein. The air valve shaft  102  includes a first pivot point  104  located opposite a second pivot point  106 . The pivot points  104 ,  106  are mounted into respective pivot holes, not shown. A finger  108  contacts the shaft  102 . The shaft  102  has a central axis of rotation  110 . It has been found that contacting the finger  108  as close to the central axis of rotation  110  as possible in this and all other embodiments presented herein minimizes any adverse rotational resistance associated with the finger  108 . In the embodiment shown in FIG. 3 the shaft  102  includes a slot  112  to receive the finger  108  and allow it to contact the shaft  102  at a location very close to the axis of rotation  110 . The slot  112  can have any shape and can be formed by removing a part of the shaft  102 . Because the shaft  102  often does not need to be capable of full rotation about its central axis of rotation  110  the slot  112  does not need to completely encircle the shaft  102 . If advantageous, however, the slot  112  can be formed as a groove that encircles the shaft  102 . This same slot  112  feature can be used when only a single finger  44  is used.  
         [0019]    The present invention finds utilization in HVAC assemblies wherein rattling of air valve shafts creates undesirable noise. The invention can be easily incorporated into the manufacturing of the housing of the HVAC assembly itself thus providing a low cost solution to the problem of air valve shaft rattling noise.  
         [0020]    The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and do come within the scope of the invention. Accordingly, the scope of legal protection afforded this invention can only be determined by studying the following claims.