Patent Application
20090149124
1. Field of the Invention
The present invention relates generally to an HVAC system. More specifically it relates to an assembly for mixing hot air and cooled air in an HVAC system.
2. Description of the Prior Art
Vehicle manufacturers are requesting HVAC modules that are smaller, lower cost, lower mass and require less time to develop. One of the components that comprise these HVAC modules is the air distribution and tempering valves. These valves which are found in production today are manufactured from metal with foam or rubber for sealing; from plastic with foam or rubber for sealing; or from fabric that is slid over a smooth plastic surface (i.e. film valve) in which air pressure pushing the fabric against the plastic surface provides the sealing. The plastic or metal valves either rotate about an axis (i.e. butterfly, end pivot) to regulate airflow through a given air passage or slide within a track (i.e. guillotine) allowing air to pass through a given air passage. While the film has take up and let-off shafts that spool and un-spool material therefore shifting apertures that are cut in the film to align with openings in the case therefore regulating airflow through a given passage.
Typically, these valves are arranged in parallel and rotate together in a 1:1 relationship. For example, the outer valves may be linked via a lever to a center valve. The center valve has a coupler for attachment to an actuator. As the actuator rotates this valve, the links transfer the motion to the outer two valves resulting in a 1:1 relationship in angular travel, i.e., all valves rotate in unison. Generally, there are two sets of valves wherein one set of valves directs cooled air exiting the evaporator and the other set of valves directs heated air exiting the heater.
Examples of such valve assemblies are disclosed in U.S. Pat. Nos. 6,254,475, and 6,814,137.
U.S. Pat. No. 6,254,475 to Danieau et al. describes an air flow control assembly including a frame carrying pivotable vanes, which are rotated on parallel axes by a common drive mechanism. The setting of the vanes is variable between a maximum flow position, in which the flaps have a minimum inclination with respect to the direction of air flow through the register, and a no-flow position in which this inclination is a maximum. The drive mechanism controls the pivoting of the vanes in such a way that they all rotate by the same degree of rotation, with adjacent vanes rotating in opposite directions.
The invention provides an HVAC system including a mechanism for simultaneously and differentially rotating valves plates different degrees of rotation and method of mixing air in an HVAC system including the step of simultaneously and differentially rotating the valve plates different degrees of rotation to control air flowing in the housing.
Typical valve assemblies, in which the valves rotate in 1:1 relationship to one another, do not promote mixing of the hot and cold air causing hot and cold air separations that impact linearity. The present invention avoids the hot and cold air separations by improving mixing of the hot and cold air streams while using a single input to actuate rotation of each valve plate.
Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, an assembly for controlling air flow in an HVAC system is generally shown.
A housing 20 defines a passage for conveying air and a blower 22 is disposed in the housing 20 for blowing the air through the passage of the housing 20. An evaporator 24 is disposed in the housing 20 for cooling the air flowing in the passage. A heater 26 is disposed in the housing 20 for heating a portion of the air flowing in the passage. A frame 28 is generally indicated and has a first half 30 generally indicated and defining a first end 32 and a second half 34 generally indicated and defining a second end 36. The frame 28 extends transversely to the passage between the first end 32 and the second end 36 in the housing 20.
A plurality of cool air valves 38 are generally indicated and are rotatably supported on the first half 30 of the frame 28 for rotation between open and closed positions to control cooled air exiting the evaporator 24. The cool air valves 38 include parallel valve plates 40 each generally indicated and each having a shaft 42 fixed relative to the valve plate 40 and with a control device 44 generally indicated and extending through the frame 28. Similarly, a plurality of warm air valves 46 are generally indicated and are rotatably supported on the second half 34 of the frame 28 for rotation between open and closed positions to control heated air exiting the heater 26. The warm air valves 46 include like parallel valve plates 40 each generally indicated and also having a shaft 42 fixed relative to the valve plate 40 and with a like control device 44 generally indicated and extending through the frame 28. The cool air valves 38 and warm air valves 46 are best illustrated in
The valve plates 40 of the valves 38, 46 may be thin, flat plates extending from the shaft 42 and having a uniform thickness as shown in
The invention is distinguished by a mechanism 48 generally shown in
For example, in an assembly having four valve plates 40 on each half of the frame 28, a specified input may rotate the valve plate 40 closest to the control device 44 of the shaft 42 positive a degrees from an open or axially aligned position, while the next closest valve plate 40 rotates a+x degrees, the third closest valve plate 40 rotates a+x+y degrees, and the valve plate 40 closest to a center of the shaft 42 rotates a+x+y+z degrees. Although the valve plates 40 in
The preferred embodiment of the mechanism 48 is shown in
The preferred embodiment of the control device 44, as best illustrated in
The preferred embodiment of the mechanism 48 includes a slide 54 defining a plurality of serpentine slots 56 wherein one of the control devices 44, e.g., one of the pins 52 is slidably disposed in each of the slots 56 for rectilinearly movement adjacent the valve plates 40. The mechanism 48 further includes a guide 58 generally indicated and extending from the first end 32 of the frame 28 to the second end 36 of the frame 28 wherein the guide 58 slidably supports the slide 54.
As shown in
The slots 56 of the slide 54 each follow a path incongruent from one another, as shown in
The mechanism 48 includes a means for maintaining at least one of said valve plates 40 stationary during rotation of remaining ones of said valve plates 40 for a dwell period. For example, in the embodiment shown in the Figures, the paths of the certain slots 56 may be arranged such that the respective valve plate 40 remains stationary for a specified angle of rotation of the input gear 66.
The invention includes a method of mixing air in an HVAC system of the type including a housing 20 defining a passage for conveying air, a plurality of parallel valve plates 40 supported in the housing 20 for rotation between open and closed positions. The method is distinguished by the step of simultaneously and differentially rotating the valve plates 40 different degrees of rotation to differentially control air flowing in the housing 20. The slide 54 is moved rectilinearly adjacent the valve plates 40 and the rectilinearly movement of the guide 58 is converted to a different degree of rotation of each respective valve plate 40.
In operation, the gear 66 is rotated a specified angle and direction which slides 54 the slide 54 along the guide 58. As the slide 54 move relative to the guide 58, the pins 52 in each slot 56 of the slide 54 move along the respective path of the slot 56. As the pins 52 move along the paths of the slots 56, the lever arms 50 on which the pins 52 are disposed rotate, thereby rotating the shafts 42 of the valves 38, 46 and the corresponding valve plates 40 fixed to the shafts 42. Because the paths of the slots 56 are incongruent from one another the pins 52 follow different paths from one another and the lever arms 50 rotate different degrees of rotation for each given input rotation of the gear 66. Accordingly, the invention is distinguished by a mechanism 48 for differentially rotating the valves 38, 46 including providing the ability to dwell any desired valves 38, 46.
While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing form the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
