Abstract:
A mounting arrangement for an HVAC case includes a drain tube extending from the HVAC case and defining an outlet. A receiving portion extends from a docking station and is adapted to accept the drain tube in an assembled position. A first compressible material is disposed between the receiving portion and the docking station. The receiving portion is operable to deflect into the first compressible material upon slidable communication of the drain tube along a surface of the neck. A second compressible material is disposed between the drain tube and the receiving portion. The second compressible material is adapted to compress between the drain tube and the receiving portion in the assembled position.

Description:
FIELD OF THE INVENTION 
   The present invention relates to HVAC systems in vehicles and more particularly to a drain tube and docking arrangement for an HVAC case. 
   BACKGROUND OF THE INVENTION 
   In automotive vehicles, it is common to have a climate control system located within an instrument panel which provides heated or cooled air to occupants through dash panel defrost air outlets, instrument panel venting air outlets and floor directed air outlets. These traditional climate control systems often include a heater core that performs heat exchange between the engine coolant, which is heated by the engine, and the cool air in the cabin/outside environment, in order to provide warm air to the passenger compartment. Some vehicles include an air conditioning system that cooperates with an evaporator for absorbing heat from the air in the vehicle. The heater core and evaporator are typically provided in an HVAC case located in the passenger compartment of the vehicle. 
   During operation, low pressure refrigerant flowing into the evaporator absorbs heat from the air inside the HVAC case for evaporation. Typically with a relatively high ambient temperature, condensation forms on the evaporator and drips onto a bottom surface of the HVAC case. In one arrangement, a drain tube directs the fluid through an outlet to an inlet of a docking station where it is discharged onto the ground. In many instances it is difficult and awkward to properly align the outlet of the drain tube with the inlet of the docking station during assembly. 
   SUMMARY OF THE INVENTION 
   A mounting arrangement for an HVAC case includes a drain tube extending from the HVAC case and defining an outlet. A neck extends from a docking station and is adapted to accept the drain tube in an assembled position. A first compressible material is disposed between the neck and the docking station. The neck is operable to deflect into the first compressible material upon slidable communication of the drain tube along a surface of the neck. 
   According to other features the neck is operable to rotate into the first compressible material upon slidable communication of the drain tube along the surface of the neck. A second compressible material is disposed between the drain tube and the neck. The second compressible material is adapted to compress between the drain tube and the neck in the assembled position. 
   According to still other features the drain tube defines a flange extending radially therearound. The flange defines a conical cross section. The drain tube defines a bulbous distal insertion end. The neck includes a funnel portion arranged on a first end. An intermediate collar extends radially around the neck. The first compressible material is disposed between the intermediate collar and the docking station. 
   Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
       FIG. 1  is a functional block diagram of an HVAC system of a vehicle; 
       FIG. 2  is a perspective view of an HVAC case drain tube and docking station inlet according to the present teachings; 
       FIG. 3  is a sectional view of the drain tube and docking station inlet of  FIG. 2  shown in an installed position; and 
       FIGS. 4-7  illustrate an assembly sequence of the drain tube and docking station of  FIG. 3  shown with the drain tube moving from an uninstalled position into an assembled position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
   With initial reference to  FIG. 1 , a block diagram of a vehicle HVAC system according to the present teachings is shown and generally identified at reference  10 . A refrigeration cycle R of the vehicle HVAC system  10  includes an air-cooling system  14 . The air-cooling system  14  includes a compressor  16  which draws, compresses, and discharges a refrigerant. The power of a vehicle engine  20  is transmitted to the compressor  16  through pulleys  22  and a belt  24 . 
   As is well known, the vehicle engine  20  drives not only the air conditioning compressor  16  but also such auxiliaries as a generator, a hydraulic pump for a power steering unit, and a coolant pump via belts and other power transmitting devices. 
   In the refrigeration cycle R, the compressor  16  discharges a superheated gas refrigerant of high temperature and high pressure, which flows into a condenser  28 . Here, heat exchange is performed with the outside air sent by a cooling fan (not shown), so that the refrigerant is cooled for condensation. The refrigerant condensed in the condenser  28  then flows into a receiver  30 , in which the refrigerant is separated into a gas and a liquid. A redundant liquid refrigerant in the refrigeration cycle R is stored inside the receiver  30 . 
   The liquid refrigerant from the receiver  30  is decompressed by an expansion valve  34  into a gas-liquid double phase state of low pressure refrigerant. The low pressure refrigerant from the expansion valve  34  flows into an evaporator  36  by way of an inlet pipe  38 . The evaporator  36  is arranged inside an HVAC case  42  of the vehicle air conditioning system  14 . The low pressure refrigerant flowing into the evaporator  36  absorbs heat from the air inside the HVAC case  42  for evaporation. An outlet pipe  40  of the evaporator  36  is connected to the suction side of the compressor  16 , so that the cycle components mentioned above constitute a closed circuit. 
   The HVAC case  42  forms a ventilation duct through which air conditioning air is sent into the passenger compartment. The HVAC case  42  contains a fan  44  which is arranged on the upstream side of the evaporator  36 . An inside/outside air switch box (not shown) is arranged on the suction side of the fan  44  (the left side in  FIG. 1 ). The air inside the passenger compartment (inside air) or the air outside the passenger compartment (outside air) switched and introduced through the inside/outside air switch box is sent into the HVAC case  42  by the fan  44 . 
   The HVAC case  42  accommodates, on the downstream side of the evaporator  36 , a hot water heater core (heat exchanger)  46 . The heater core  46  includes an inlet pipe  48  and an outlet pipe  50 . Hot water (coolant) of the vehicle engine  20  is directed to the heater core  46  through the inlet pipe  48  by a water pump  52 . A water valve  54  controls the flow volume of engine coolant supplied to the heater core  46 . A radiator  56  and a thermistor  58  further cooperate to control the temperature of the coolant. 
   A bypass channel  60  is formed beside the hot water heater core  46 . An air mix door  62  is provided to adjust the volume ratio between warm air and cool air that passes through the hot water heater core  46  and the bypass channel  60 , respectively. The air mix door  62  adjusts the temperature of the air blown into the passenger compartment by adjusting the volume ratio between the warm air and cool air. 
   Additionally, a face outlet  64 , a foot outlet  68 , and a defroster outlet  70  are formed at the downstream end of the HVAC case  42 . The face outlet  64  directs air toward the upper body portions of passengers, the foot outlet  68  directs air toward the feet of the passengers, and the defroster outlet  70  directs air toward the internal surface of a windshield. The outlets  64 ,  58  and  70  are opened and closed by an outlet mode doors (not shown). The air mix door  62  and the outlet mode doors mentioned above are driven by such electric driving devices such as servo motors via linkages or the like. 
   With further reference now to  FIGS. 2 and 3  a mounting arrangement according to the present teachings is shown and generally identified at reference  78 . The mounting arrangement  78  generally includes an outlet  80  of the HVAC case  42  and an inlet  82  of a docking station  86 . In general, during operation of the evaporator  36 , condensation formed on the evaporator  36  drips downward from the evaporator  36  and collects into the HVAC case  42 . The condensation drains out of the HVAC case  42  through a drain tube  90  defining the outlet  80 . From the outlet  80  of HVAC case  42 , the condensation enters the inlet  82  of a receiving portion or drain neck  92  provided on the docking station  86 . The drain neck  92  exhausts the condensation through an exit port  96  and onto the ground. 
   With continued reference now to  FIGS. 2 and 3 , the drain tube  90  of the HVAC case  42  and the neck  92  of the docking station  86  will be described in greater detail. The mounting arrangement  78  of the present invention facilitates insertion of the drain tube  90  into the neck  92  provided on the docking station  86 . As a result, the outlet  80  of the HVAC case  42  may be easily located into the inlet  82  of the neck  92  on the docking station  86  accounting for build tolerance and assembly process variations. 
   The drain tube  90  generally includes an upstream longitudinal portion  100  defining an inner diameter d 1  and a downstream radial portion  102 . A flange  104  extends radially around the longitudinal portion  100  and generally tapers toward the radial portion  102 . The flange defines a conical cross-section. The radial portion  102  generally defines a bulbous distal portion suitable for nesting into a receiving end of the neck  92 . A compressible packing material such as foam  110  is arranged adjacent the flange  104 . The compressible packing material  110  may comprise a generally tapered outer contour similar to the flange  104 . 
   The neck  92  of the docking station  86  generally includes an upper funnel portion  112  having an upper seat  116 , an intermediate portion  120  defining an inner diameter d 2  and a lower insertion portion  122 . The upper seat  116  of the neck  92  defines a generally conical contour. A ramp portion  124  is provided on the upper seat  116  for accommodating ingress of the drain tube  90  during assembly as will be described in greater detail. 
   The seat  116  is arranged to substantially align with the flange  104  and foam  110  of the drain tube  90  on the HVAC case  42  in an assembled position ( FIG. 3 ). An outer ridge  128  defined on the neck  92  is adapted to capture the neck  92  within a passage  130  defined through the docking station  86 . A compressible material such as foam  132  is located between an intermediate collar  134  of the neck  92  and the docking station  86  in an assembled position. The compressible material  132  is operable to compress and retract according to interaction between the drain tube  90  and the neck  92 . In this way, the characteristics of the compressible material  132  urge the outer ridge  128  of the neck  92  into the docking station  86  maintaining a tight fit. It is appreciated that the compressible material  132  may comprise other materials or alternatively may comprise a mechanical biasing configuration. 
   With general reference now to  FIG. 3  (assembled position) and specific reference to  FIGS. 4-7 , an assembly sequence for locating the drain tube  90  of the HVAC case  42  into the neck  92  provided on the docking station  86  will be described in further detail. In general, the compressible material  132  allows the neck  92  to rotate in a clockwise direction relative to the docking station  86  as the radial portion  102  of the drain tube  90  slidably engages and eventually clears the ramp  124  to reach the installed position ( FIG. 3 ). As a result of this interaction, the neck  92  and the docking station  86  centralize around the drain tube  90  once installed. 
     FIG. 4  illustrates the drain tube  90  initially contacting the ramp  124  of the neck  92 . As illustrated, the compressible material  132  initially compresses causing the neck  92  to rotate clockwise. Explained further, an interface between the ridge  128  and the docking station  86  defines a gap g 1  on the portion of the neck  92  corresponding to the ramp  124  (the rightmost portion of the ridge  128  as viewed from  FIG. 4 ). The gap g 1  is created by clockwise rotation of the neck  92  about a contact surface on the leftmost portion of the ridge  128  and the corresponding surface of the docking station  86 . 
   Turning now to  FIG. 5 , the drain tube  90  is shown shifted leftward relative to  FIG. 4 . In  FIG. 5 , the radial portion  102  of the drain tube  90  causes the neck  92  to deflect into the compressible material  132 . As a result, the compressible material  132  compresses a distance causing the neck  92  to further rotate clockwise. A gap g 2  is defined between the ridge  128  and the docking station  86 .  FIG. 6  illustrates the drain tube  90  shifted leftward relative to  FIG. 5 . In  FIG. 6  an outermost surface of the radial portion  102  engages an outermost portion of the ramp  124  resulting in the greatest amount of compression in the compressible material  132  and the furthest rotation clockwise of the neck  92 . A gap g 3  is defined between the ridge  128  and the docking station  86 . In general the relative gaps may be represented as g 3 &gt;g 2 &gt;g 1 . 
   In  FIG. 7 , the drain tube  90  is shown shifted leftward relative to  FIG. 6 . The radial portion  102  of the drain tube  90  is shown partially nested into the funnel  112 . At this point the compressible material  132  begins to retract or rebound and the neck  92  rotates counterclockwise. In the fully assembled position ( FIG. 3 ), the drain tube  90  nests within the funnel  112 . The compressible packing material  110  arranged around the flange  104  of the drain tube  90  partially compresses against the seat  116  to encourage a seal thereat. The dimensional relationship of the radial portion  102  of the drain tube  90  and the funnel portion  112  of the neck  92  encourage the drain tube  90  to centralize relative to the neck  92  in an assembled position. 
   The drain tube  90  and the neck  92  may be made of a durable, lightweight material such as injection molded plastic for example. It is appreciated that the drain tube  90  may be an integral piece of the HVAC case  42  or alternatively a distinct component attached to the HVAC case  42 . Similarly, the neck  92  may alternatively be an integral structure of the docking station  86 . Other materials and configurations may also be employed while reaching similar results. 
   Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims.