US20080307807A1

US20080307807A1 - Air Damper Units for Refrigerators and Control Methods Therefor

Info

Publication number: US20080307807A1
Application number: US11/762,419
Authority: US
Inventors: Timothy E. Graff; Steven J. Vornsand
Original assignee: Emerson Electric Co
Current assignee: Emerson Electric Co
Priority date: 2007-06-13
Filing date: 2007-06-13
Publication date: 2008-12-18

Abstract

An air damper unit for a refrigerator includes a printed circuit board, a sliding door movably mounted to the printed circuit board, a damper position sensor for detecting the position of the sliding door, and a driving mechanism. The sliding door regulates the air flow from a freezer compartment into a refrigerator compartment. A microcontroller is mounted on the printed circuit board for controlling the operation of the sliding door. The microcontroller controls the driving mechanism according to a signal corresponding to a position of the sliding door from the damper position sensor. The continuous feedback from the damper position sensor enables the microcontroller to more effectively control the operation of the sliding door and maintain the temperature setting of the refrigerator compartment.

Description

FIELD

The present disclosure relates generally to refrigerators and more particularly to air damper units for refrigerators and related control methods.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Known refrigerators typically include a freezer compartment and a refrigerator compartment separated by a partition wall. A compressor system of the refrigerator cools the air in the freezer compartment directly, whereas the refrigerator compartment is cooled by the cold air directed from the freezer compartment into the refrigerator compartment through an air passageway disposed in the partition wall. An air damper is generally mounted adjacent to the air passageway to control the opening of the air passageway, thereby regulating the amount of air flow into the refrigerator compartment and, ultimately, the temperature of the refrigerator compartment. The air damper may be controlled automatically or manually. Whether automatically or manually, however, the air damper is either fully open or fully closed in response to a thermostat or a temperature sensor indicating whether or not the temperature of the refrigerator compartment has reached a predetermined temperature setting.
The prior art air damper typically can move only between two positions (fully closed or fully open) and thus has a disadvantage in maintaining the refrigerator compartment at a predetermined temperature setting. When the air damper is in a fully-closed position, the cold air from the freezer compartment is completely blocked and no cooling is applied to the refrigerator compartment. When the air damper is in a fully open position, a maximum amount of cold air is allowed to enter the refrigerator compartment to significantly reduce the temperature of the refrigerator compartment. It is difficult to use the prior art air damper for a small range of temperature adjustment when the air damper can move only between two positions. Moreover, without being able to monitor the position of the air damper during operation, the air damper is generally operated to a reference position before the air damper can be moved to a desired position.
Therefore, it is desirable to obtain an air damper with improved control of the opening of the air passageway in order to better maintain a predetermined temperature setting in the refrigerator compartment.

SUMMARY

In one form, an air damper unit for a refrigerator includes a printed circuit board, a sliding door movably mounted to the printed circuit board, and a damper position sensor for detecting the position of the sliding door relative to the printed circuit board. The printed circuit board defines at least one aperture and the sliding door is mounted adjacent to the aperture for regulating the opening of the aperture.
In another form, an air damper control system for an air damper having a sliding door includes a microcontroller and a damper position sensor operably connected to the microcontroller for detecting the position of the sliding door. The microcontroller controls the operation of the sliding door according to a signal corresponding to the position of the sliding door from the damper position sensor.
In yet another form, a method of operating an air damper unit which includes a sliding door and a driving mechanism includes: detecting the position of the sliding door; and operating the sliding door according to the position of the sliding door.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

FIG. 1 is a perspective view of a refrigerator including an air damper unit constructed in accordance with the teachings of the present disclosure;

FIG. 2 is a plan view of an air damper unit constructed in accordance with the teachings of the present disclosure, showing the air damper unit in a fully open position;

FIGS. 2 a and 2 b are enlarged detail views of a portion of the air damper unit of FIG. 2, showing a damper position sensor;

FIG. 3 is a partial cross-sectional side view showing a portion of an air damper unit, taken along line 3-3 of FIG. 2;

FIG. 4 is a plan view of a printed circuit board of an air damper unit;

FIG. 5 is a plan view of an air damper unit, showing the air damper unit in a fully closed position;

FIG. 6 is plan view of an alternative air damper unit constructed in accordance with the teachings of the present disclosure, showing the air damper unit in a fully open position;

FIG. 7 is a partial cross-sectional side view showing a portion of an air damper unit, taken along line 7-7 of FIG. 6;

FIG. 8 is a plan view of a printed circuit board of an air damper unit;

FIG. 9 is a partial exploded view of an alternative air damper unit constructed in accordance with the teachings of the present disclosure, showing the air damper unit in a fully open position;

FIG. 10 is a bottom perspective view of a housing of the air damper unit of FIG. 9;

FIG. 11 is a perspective view of the air damper unit of FIG. 9, showing the air damper unit in a fully closed position with the housing removed from clarity;

FIG. 12 is a top view of the housing of FIG. 10, showing a fan mounted to the housing;

FIG. 13 is a schematic block diagram showing an air damper unit in accordance with the teachings of the present disclosure;

FIG. 14 is a circuit diagram for an exemplary microcontroller of a damper control system constructed in accordance with the teachings of the present disclosure;

FIG. 15 is a circuit diagram for an exemplary damper position sensor of a damper control system constructed in accordance with the teachings of the present disclosure;

FIG. 16 is a circuit diagram for an exemplary bidirectional motor drive of a damper control system constructed in accordance with the teachings of the present disclosure;

FIG. 17 is a circuit diagram for an exemplary power supply of a damper control system constructed in accordance with the teachings of the present disclosure;

FIG. 18 is a circuit diagram for an exemplary data interface of a damper control system constructed in accordance with the teachings of the present disclosure;

FIG. 19 is a circuit diagram for an exemplary de-icing heater drive of a damper control system constructed in accordance with the teachings of the present disclosure;

FIG. 20 is a circuit diagram for an exemplary fan motor drive of a damper control system constructed in accordance with the teachings of the present disclosure; and

FIG. 21 is a circuit diagram for an exemplary external temperature sensor of a damper control system constructed in accordance with the teachings of the present disclosure.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Referring to FIG. 1, a refrigerator is illustrated and generally indicated by reference numeral 10. The refrigerator 10 includes a block-shaped cabinet 12, a partition wall 14, a freezer compartment 16 and a refrigerator compartment 18 separated by the partition wall 14. The freezer compartment 16 is cooled directly by a compressor unit 17 (depicted in FIG. 13) of the refrigerator 10. The refrigerator compartment 18 is cooled by the cold air flowing from the freezer compartment 16 through an air passageway 20 defined in the partition wall 14 to the refrigerator compartment 18.
Referring to FIGS. 2 and 3, an air damper unit constructed in accordance with the teachings of the present disclosure is illustrated and generally indicated by reference number 22. The air damper unit 22 is disposed in the refrigerator compartment 18 and on the partition wall 14. The air damper unit 22 includes a printed circuit board 24, a sliding door 26 movably mounted on the printed circuit board 24, and an air damper control system 28 (shown in FIG. 13) for controlling the movement of the sliding door 26. The printed circuit board 24 is mounted on the partition wall 14 adjacent to the air passageway 20.
As shown in FIG. 4, the printed circuit board 24 includes a gate area 30 defining a plurality of aperture 32 and a plurality of blocking areas 34 between the apertures 32. The gate area 30 has a shape and a size corresponding to that of the air passageway 20. In the drawings, four apertures 32 and four blocking areas 34 are shown in the printed circuit board 24. Of course, any desired number of apertures and blocking areas may be incorporated. The gate area 30 is shown to have a circular shape and the apertures 32 and the blocking areas 34 have a circular sector shape. Similarly, the gate area, apertures and blocking areas may take any desired shape.
Referring back to FIGS. 2 and 3, the sliding door 26 has a central shaft 38, a peripheral flange 40, and four apertures 42 and four blocking areas 44 between the central shaft 38 and the peripheral flange 40. The shape and size of the apertures 42 and the blocking areas 44 of the sliding door 26 substantially correspond to the shape and size of the apertures 32 and the blocking areas 34 of the printed circuit board 24. When the apertures 42 of the sliding door 26 are aligned with the apertures 32 of the printed circuit board 24, the air damper unit 10 is in its fully open position to allow a maximum amount of cold air to flow from the freezer compartment 16 to the refrigerator compartment 18 as shown in FIG. 2. When the blocking areas 44 of the sliding door 26 are aligned with the apertures 32 of the printed circuit board 24, the air damper unit 10 is in its fully closed position to block the cold air from entering the refrigerator compartment 18 as shown in FIG. 5. When the apertures 34 and 42 of the printed circuit board 24 and the sliding door 26 are not aligned as indicated by dashed lines of FIG. 2, a variable amount of cold air is allowed to enter the refrigerator compartment 18.
As best seen in FIG. 3, a damper position sensor 46 is provided to detect the position of the sliding door 26. The damper position sensor 46 can be, by way of example, a potentiometer, a Hall effects sensor, or any optical position detecting devices. In this illustrative example, the damper position sensor 46 includes a fixed member 48, such as a variable resistor 47 (see FIG. 2), and a moving member 50, such as a sliding contact. The fixed member 48 is provided on the printed circuit board 24 and arranged along the peripheral flange 40 of the sliding door 26. The moving member 50 is disposed on the peripheral flange 40 and in contact with the fixed member 48 as the sliding door 26 rotates relative to the printed circuit board 24. By determining the position of the moving member 50, the position of the sliding door 26 can be determined and, hence, the amount of cold air allowed to enter the refrigerator compartment 18 can be precisely controlled.
Alternatively, the fixed member 48 of the damper position sensor 46 can be in the form of a plurality of discrete fixed contacts 49 (see FIGS. 2 a and 2 b) disposed on the printed circuit board 24 at intervals along the peripheral flange 40 of the sliding door 26. With the discrete fixed contacts 49, a signal corresponding to the position of the sliding door 40 is generated only when the sliding contact 50 contacts the fixed contacts 49. In such an embodiment, the discrete fixed contacts 49 can be spaced at regular intervals (x) or they can be disposed at variable intervals (x₁, x₂, x₃, s₄, . . . ) along the peripheral flange 40 of the sliding door 26.
The driving mechanism 52 includes a bi-directional DC motor 54 and a reduction gear 56 operably connected to the central shaft 38 of the sliding door 26 for rotatably driving the sliding door 26. The driving mechanism 52 is connected to an outside power supply (not shown) through an edge connector 58 mounted on one edge 60 of the printed circuit board 24. The voltage for the motor 54 is preferably between 5V DC and 20V DC.
Preferably, a defroster 62 is provided on the printed circuit board 24 for deicing ice that can form between the peripheral flange 40 of the sliding door 26 and the printed circuit board 24. In this illustrative example, the defroster 62 is in the form of a plurality of discrete heaters (e.g., resistors) disposed on the printed circuit board 24 adjacent to the peripheral flange 40 of the sliding door 26.
Optionally, a control knob (not shown) can be provided at the sliding door 26 for manual operation of the sliding door 26.
Referring to FIGS. 6 to 8, an alternative air damper unit constructed in accordance with the teachings of the present disclosure is illustrated and generally indicated by reference numeral 70. In the following, the components similar to those described in connection with FIGS. 2 to 5 will be indicated by like reference numerals for clarity.
The air damper unit 70 includes a printed circuit board 72, a sliding door 74, a driving mechanism 52, and an air damper control system 28 (FIG. 13). The printed circuit board 72 has a gate area 76 (FIG. 8) defining a plurality of rectangular apertures 78. The sliding door 74 is placed adjacent to the gate area 76. The sliding door 74 defines a plurality of rectangular apertures 80 having a size and a shape corresponding to those of the apertures 78 of the printed circuit board 72. The sliding door 74 has a plurality of cross bars 82 between the apertures 80.
The sliding door 74 includes a driven end 84 engaging the driving mechanism 52. The driving mechanism 52 includes a bi-directional motor 54, a reduction gear 56 for driving the sliding door 74 back and forth in a linear motion to regulate the air flow passing through the apertures 80 of the sliding door 74. The reduction gear 56 can be replaced with a worm gear for imparting the back-and-forth movement. A position sensor 86 is provided to detect the position of the sliding door 74. The position sensor 86 includes a fixed member 88 on the printed circuit board 72 and a moving member 90 on the driven end 84 of the sliding door 74. The fixed member 88 can be a variable resistor or a plurality of discrete fixed contacts arranged along the length of the driven end 116 of the sliding door 74. The moving member 90 can be a moving contact for contacting the fixed member 88.
Referring to FIGS. 9 to 11, an alternative air damper unit constructed in accordance with the teachings of the present disclosure is illustrated and indicated generally by reference numeral 120. The air damper unit 120 includes a housing 122 defining a receiving space 124 (clearly shown in FIG. 10), a printed circuit board 126 disposed inside the receiving space 124, a sliding door 128 slidingly mounted on the printed circuit board 126, and a driving mechanism 130 mounted on the printed circuit board 126 for driving the sliding door 128.
The housing 122 defines an aperture 136 to be aligned with the air passageway 20 of the partition wall 14 of the refrigerator 10. The printed circuit board 126 has an aperture 138 aligned with the opening 136 of the housing 122. The sliding door 128 is driven by the driving mechanism 130 to slide along a longitudinal direction of the printed circuit board 126 to control the opening of the aperture 138 of the printed circuit board 126.
The driving mechanism 130 includes a bi-directional motor 132 and a screw 134. The screw 134 has one end connected to a rotor (not shown) of the motor 132 and the other end supported on a support member 140 of the housing 122. The screw 134 passes through a nut 142 provided on the sliding door 128. As the motor 132 drives the screw 134 to rotate, the rotation of the screw 134 causes the nut 142 and hence the sliding door 128 to move linearly along a longitudinal direction of the screw 134. When the motor 132 rotates in one direction, the sliding door 128 is driven to move toward the motor 132 to open the aperture 138 (as shown in FIG. 9). When the motor 132 reverses its rotating direction, the sliding door 128 is driven to move away from the motor 132 to close the aperture 138 (as shown in FIG. 11).
The sliding door 128 has a pair of guide rails 129 extending toward and received within a pair of corresponding guide slots 131 of the housing 122 so that the sliding door 128 can properly slide within the housing 122.
Compared with the air damper units 22, 70, the air damper unit 120 has the advantage of allowing more cold air to flow through when the air damper unit 120 is in its fully open position since no blocking areas are present in the aperture 138. Therefore, the air damper unit 120 allows the refrigerator compartment 18 to quickly reach the predetermined temperature settings.
Like the air damper units 22 and 70, the air damper unit 120 includes a damper position sensor (not shown) disposed on the printed circuit board 126 to detect the position of the sliding door 126. Because the damper position sensor used with the air damper unit 120 is similar to those described in connection with FIGS. 2 to 8, the description thereof is omitted herein for clarify.
Optionally, as shown in FIGS. 9 and 12, a fan 92 may be mounted to the housing 122 and disposed inside the aperture 136 to help draw the cold air form the freezer compartment 16 into the refrigerator compartment 18 to improve air circulation. Preferably, an integral air filter 144 may be mounted to the housing 122 to cover the aperture 136 of the housing 122 to provide good-quality air flowing into the refrigerator compartment 18. The air filter 144 can be made replaceable.
It should be understood that while the air damper units 24 and 70 described in FIGS. 2 to 8 are not shown to have a housing to cover the printed circuit boards 24 and 72, the housing 122 can be modified to have a circular aperture or a rectangular aperture to match and to be aligned with the gate areas 30 and 76 of the air damper units 24 and 70. The fan 92 can also be provided in the circular aperture or the rectangular aperture of the modified housing to improve air circulation.
Referring to FIGS. 13 to 21, the air damper control system 28 and the method of controlling the air damper unit 22, 70, or 120 are now described in more detail. As shown, in addition to a central microcontroller 118 for controlling the operation of a compressor unit 17, the refrigerator 10 includes a microcontroller 100 on the printed circuit board 24, 72 or 126. The air damper control system 28 includes the microcontroller 100 and a variety of control circuits on the printed circuit board 24, 72 or 126 for controlling the operation of the air damper unit 22, 70 or 120. By way of example and with reference to FIGS. 14 to 21, the control circuits may include a microcontroller circuit 102 (FIG. 14), a damper position sensor circuit 104 (FIG. 15), a bidirectional motor circuit 106 (FIG. 16), a power supply circuit 108 (FIG. 17), a data interface circuit 110 (FIG. 18), a deicing heater drive circuit 112 (FIG. 19), a fan motor drive circuit 114 (FIG. 20), a temperature sensor circuit 116 (FIG. 21), and a jam detecting circuit (not shown). The air damper control system 28 controls the driving mechanism 52 and thus the operation of the sliding door 26. The air damper control system 28, through the microcontroller 100, has the ability to receive commands and transmit responses between the central microcontroller 118 and the air damper unit 22, 70, or 120.
During operation of the refrigerator 10, the damper position sensor 46 or 86 continuously transmits a signal corresponding to the position of the sliding door 26, 74, or 128 to the microcontroller 100 of the air damper unit 22, 70, or 120. A temperature sensor 94 (shown in FIG. 12) which can be directly mounted on the printed circuit board 24, 72, or 126 or remotely mounted from the air damper unit 22, 70, or 120 also transmits a signal corresponding to the temperature of the refrigerator compartment 18. Based on the temperature of the refrigerator compartment 18, the microcontroller 100 determines whether the air damper unit 22, 70, or 120 should be further open or closed. With the feedback from the damper position sensor 46 or 86 indicating the position of the sliding door 26, 74, or 128, the microcontroller 100 determines how the sliding door 26, 74 or 128 should be moved and commands the driving mechanism 52 or 130 to operate the sliding door 26, 74, or 128 accordingly. Because the temperature sensor 94 and the damper position sensor 46 or 86 constantly send a signal to the microcontroller 100, the microcontroller 100 can continuously control the operation of the sliding door 26, 74, or 128 and more effectively and efficiently control the temperature of the refrigerator compartment 18.
The microcontroller 100 can also control the defroster 62 in response to a signal transmitted from the jam detecting circuit. By way of example, the jam detecting circuit may include a current spike detector for detecting a current spike in the DC motor 54 or 132. When ice formed between the sliding door 26, 74, or 128 and the printed circuit board 24, 84, or 126 prevents the sliding door 26, 74, or 128 from moving, a current spike is experienced in the DC motor 54 or 132. The jam detecting circuit then generates a signal corresponding to the current spike to the microcontroller 100. The microcontroller 100 can then send a signal to the deicing heater drive circuit 112 to activate the defroster 62. Alternatively, the jam detecting circuit may include a position sensing element (not shown) separate from or incorporated into the damper position sensor 46 or 86. In response to a non-moving condition of the sliding door 26, 74, or 128, the jam detecting circuit generates and sends a signal to the microcontroller 100, which in turn, commands the deicing heater drive circuit 112 to activate the defroster 62. The defroster 62 may be activated regularly to avoid ice being formed between the sliding door 26, 74, or 128 and the printed circuit board 24, 84, or 126 to ensure a smooth movement of the sliding door 26, 74, or 128.
The fan motor drive circuit 114 controls the operation of the fan 92. The fan 92 can be switched on/off at a regular interval or depending on the operation of the sliding door 26, 74, or 128 to improve air circulation. The fan 92 may be activated to operate at different speeds depending on needs.
In addition to the automatic temperature regulation mode previously described, the damper control system 28 can be configured to be also operable under a manual control mode. By switching the damper control system 28 to a manual control mode, a user can operate the sliding door 26, 74, or 128 manually by using a control knob (not shown) provided on the sliding door 26, 74, or 128, if desired.
The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

Claims

1. An air damper unit for a refrigerator, comprising:

a printed circuit board defining at least one aperture therethrough;

a sliding door movably mounted to the printed circuit board adjacent to the aperture for regulating the opening of the aperture; and

a damper position sensor for detecting the position of the sliding door relative to the aperture.

2. The air damper unit of claim 1, further comprising a microcontroller mounted on the printed circuit board.

3. The air damper unit of claim 2, further comprising a driving mechanism for driving the sliding door.

4. The air damper unit of claim 2, wherein the driving mechanism includes a bi-directional motor and a screw.

5. The air damper unit of claim 4, wherein the sliding door is driven by the screw and the screw is driven by the bi-directional motor.

6. The air damper unit of claim 3, wherein the microcontroller controls the driving mechanism according to the position of the sliding door.

7. The air damper unit of claim 1, further comprising a defroster mounted on the printed circuit board.

8. The air damper unit of claim 7, wherein the defroster includes a plurality of resistors adjacent to the sliding door.

9. The air damper unit of claim 1, wherein the damper position sensor is selected from a group consisting of potentiometer and hall effect sensor.

10. The air damper unit of claim 1, wherein the damper position sensor includes a variable resistor on the printed circuit board and a moving contact on the sliding door.

11. The air damper unit of claim 10, wherein the variable resistor is provided along a periphery of the sliding door and the moving contact is provided at the periphery of the sliding door.

12. The air damper unit of claim 1, wherein the damper position sensor includes a plurality of fixed contacts on the printed circuit board, and a moving contact on the sliding door.

13. The air damper unit of claim 1, wherein the sliding door has a circular shape and is rotatably movable relative to the circuit board.

14. The air damper unit of claim 1, wherein the sliding door has a rectangular shape and is movable in a linear direction relative to the circuit board.

15. The air damper unit of claim 1, further comprising a knob mounted to the sliding door for manually moving the sliding door relative to the circuit board.

16. The air damper unit of claim 1, further comprising a housing for receiving the printed circuit board and the sliding door therein, the housing having an aperture adjacent to the aperture of the printed circuit board.

17. The air damper unit of claim 16, further comprising a fan mounted to the housing and disposed in the aperture of the housing.

18. The air damper unit of claim 16, further comprising an air filter mounted on the housing for covering the aperture of the housing.

19. An air damper control system for an air damper unit having a sliding door, comprising:

a microcontroller; and

a damper position sensor operably connected to the microcontroller for detecting the position of the sliding door,

wherein the microcontroller controls the operation of the sliding door according to a signal corresponding to the position of the sliding door from the damper position sensor.

20. The air damper control system of claim 19, further comprising a printed circuit board on which the microcontroller is disposed.

21. The air damper control system of claim 20, wherein the damper position sensor includes at least one fixed contact on the printed circuit board and a moving contact on the sliding door.

22. The air damper control system of claim 21, wherein the fixed contact is in the form of a variable resistor.

23. The air damper control system of claim 21, further comprising a plurality of discrete fixed contacts.

24. The air damper control system of claim 20, further comprising a temperature sensor on the printed circuit board.

25. The air damper control system of claim 19, further comprising a driving mechanism for driving the sliding door.

26. The air damper control system of claim 25, wherein the driving mechanism is controlled by the microcontroller.

27. A method of operating an air damper unit, the air damper unit including a sliding door and a driving mechanism, the method comprising:

detecting the position of the sliding door; and

operating the sliding door according to the position of the sliding door.

28. The method of claim 27, further comprising generating a position signal corresponding to the position of the sliding door.

29. The method of claim 28, further comprising using a microcontroller to control the operation of the sliding door according to the position signal.

30. The method of claim 27, further comprising providing a continuous feedback of the position of the sliding door to a microcontroller.

31. The method of claim 27, further comprising using a damper position sensor to provide a continuous feedback of the position of the sliding door.