JP3291346B2 - refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator having a damper device for adjusting the flow rate of cold air to a storage room of a refrigerator, and using a shape memory alloy coil spring as a drive source of the damper device.

[0002]

2. Description of the Related Art In a general refrigerator having a freezer compartment and a refrigerator compartment, cold air cooled by a cooler in a cooler compartment is sent to a refrigerator compartment through a damper device and a cool air duct to cool the refrigerator compartment. Is configured. Here, the damper device is attached to the inlet portion of the cold air duct, and when the temperature in the refrigerator compartment rises above the upper limit temperature, the opening of the damper device is opened to perform cold air circulation to the cool air duct, and the temperature in the refrigerator compartment reaches the lower limit temperature. When the temperature is lowered to below, the opening is closed and the operation of stopping the flow of the cool air to the cool air duct is performed. Examples of the damper device include a gas-filled damper thermostat, a motor-driven motor damper, and a shape memory damper using a shape memory alloy coil spring as a drive source.

As a disclosure of this shape memory damper, for example, Japanese Unexamined Utility Model Publication No. Hei 3-7582 and Japanese Unexamined Patent Publication No. Hei.
No. 3258 and the like. As shown in FIG. 9, the damper device disclosed in these publications has a damper baffle plate 101 for opening and closing an opening communicating with a cool air duct for sending cool air from a cooler room to a refrigerator room, and a rotating shaft for opening and closing the damper baffle plate. And a damper base 102 fixed in the cool air duct. Then, a DC voltage Vcc (for example, 12 V DC) is applied from a DC power supply 106 to the heater 104 wound and wound on the spiral shape memory alloy coil spring 103 as shown in FIG. Is heated directly. Here, the shape memory alloy coil spring 103
When the material is heated to an austenite phase transition end temperature Af (hereinafter, simply referred to as an Af point) or more, a contraction force is generated by a shape memory effect of restoring a stored original shape. In FIG. 9, the shape memory alloy coil spring 103 has a damper baffle plate 101 at one end.
Of the baffle plate 101 and the base 102
In the direction opposite to the direction in which the baffle plate is rotated by the contraction force of the shape memory alloy coil spring 103 (that is, in the direction opposite to)
The bias spring 105 is hooked so as to urge the baffle plate.

When the refrigerator compartment is to be cooled, the heater 104 is energized and the shape memory alloy coil spring 103 is set to Af.
Is heated above the point, the contraction force at the point Af or more is contracted to the shape memory alloy coil spring set to be larger than the biasing force of the bias spring 105, and the damper baffle plate 101 is lifted by the contraction force to cool the air. Open the opening of the duct (specifically, the damper base). As a result, cool air flows from the cooler room into the refrigerator room to cool the refrigerator room.

On the other hand, when the cooling of the refrigerating compartment is stopped, the application of the DC voltage Vcc is stopped to stop the power supply to the heater 104, and the shape memory alloy coil spring is transformed into a martensitic phase transition by cold air around the damper device. The temperature is cooled below the end temperature Mf (hereinafter simply referred to as Mf point), the contraction force of the shape memory alloy coil spring is released or reduced, and the damper-baffle plate is pulled down by the biasing force of the bias spring so that the cold air duct (specifically, the damper base) Close the opening. As a result, the flow of cool air from the cooler room to the refrigerator compartment stops, and the cooling of the refrigerator compartment stops.

When a shape memory damper is used for a refrigerator, it is generally necessary to guarantee the number of times of opening and closing the damper device from 100,000 to 300,000 or more. The heat cycle fatigue characteristics and the repetition characteristics are required, and in use, it is necessary to perform a fatigue test under actual use conditions.

[0007] Also, the part to which the damper device is attached is
When the blower is in operation, it is constantly exposed to cold air of about -20 to -25 ° C. Therefore, the material of the shape memory alloy coil spring is cooled to a lower limit temperature (that is, the Mf point) for closing the baffle plate by -25. ° C, and further, the heating amount when heating the shape memory alloy coil spring to open the baffle plate is larger than the cooling amount of the cool air sent by the blower, and the heating upper limit temperature at the time of reverse transformation is set. It is necessary to set the temperature much higher than the temperature set in the refrigerator compartment (for example, 70 ° C. or more if the Af point is 70 ° C.). Therefore, the operating temperature range of the shape memory alloy coil spring and hence the damper device is in the range of about -25 to 70 ° C.

Generally, as shown in FIG. 5, in a cooling process having a large hysteresis width, transformation occurs in two stages of an intermediate phase (so-called land-hedral phase (hereinafter simply referred to as R phase)) and a martensite phase (hereinafter simply referred to as M phase). Shape memory alloys (especially those in which an R-phase exists and a bias load (bias spring) combined) are used,
As the phase transformation, B2 → R → M → B2 is used.
As specific examples, an Af point of 70 ° C., an austenite phase transition onset temperature As (hereinafter simply referred to as As point) 53 ° C., a martensite phase transition onset temperature Ms ′ (hereinafter simply referred to as Ms ′ point) in the R phase of 55 ° C. Martensite phase transition end temperature Mf '(hereinafter simply referred to as Mf' point) in the phase 46 ° C., martensite phase transition onset temperature Ms in the M phase (hereinafter simply referred to as the Ms point)
A shape memory alloy (TiNi alloy not using aging treatment) in a temperature range around -18 ° C at 9 ° C, the martensite phase transition completion temperature Mf (hereinafter simply referred to as Mf point) in the M phase, is generally used.

[0009]

As a first disadvantage of the conventional shape memory damper, a reverse transformation (that is, opening an opening) is performed.
The heater 4 is sometimes energized, and the electric current to the heater 4 is cut off during the transformation (that is, when the opening is closed). In general, the use of only the B2 → M and M → B2 transformations results in poor life characteristics of the shape memory alloy. (That is, the life is short) and the amount of distortion is also large. In addition, when our conventional refrigerator was equipped with a conventional shape memory damper, we confirmed that the stress (shrinkage force) generated when the shape memory alloy was heated and inversely transformed into the parent phase was reduced to the initial value (when starting to use). On the other hand, when compared with the case where the damper is opened and closed several thousand times, it was confirmed that the damper significantly decreased.

As a second disadvantage, when the refrigerator is cooled, the heater 4 is energized to reversely transform the shape memory alloy 3 to open the damper baffle plate 1 by the contraction force. Cold air at a low temperature of about -25 ° C. is in contact with the shape memory alloy 3 and the heater 4, and particularly the heater 4 having a small heat capacity takes more heat than when there is no wind. For this reason, in order to heat the shape memory alloy to the Af point (for example, 70 ° C.) or more when the shape memory alloy is reversely transformed in a cooled state, the heater resistance value and applied voltage are set so as to generate a considerably large amount of heat. The power consumption is obviously higher than when there is no wind, so that there is a problem that the power consumption is wasted. When the cooling of the refrigerating compartment is stopped, the energization of the heater 4 is interrupted to transform the shape memory alloy 3 and close the damper baffle plate 1. However, when the blower is operated, the circulating cold air flows. The shape memory alloy is cooled quickly, so that the damper baffle plate 1 closes quickly, but when the blower is stopped, no cool air is supplied, so the shape memory alloy 3 cannot be cooled quickly and the damper baffle plate 1 closes quickly. There were drawbacks that could not be done.

Therefore, in the present invention, the method of energizing the heater wound around the shape memory alloy coil spring is reversed from the conventional method, while a small current is always supplied to the heater when the open / close plate is opened (that is, during cooling). An object of the present invention is to provide a refrigerator in which the temperature of a shape memory alloy coil spring is maintained at the Ms point or higher and the shape memory alloy coil spring can be used only in the R-phase transformation (that is, R → B2, B2 → R transformation). .

Further, the present invention reduces the duty ratio to the heater after closing the open / close plate during heating so that the temperature of the shape memory alloy coil spring does not rise too much beyond the point Af. An object of the present invention is to provide a refrigerator in which the temperature range during cooling is reduced.

[0013]

According to the present invention, there is provided a cooling device comprising:
A cold air duct that guides the cooled air to the storage room,
Damper device for controlling the flow of cold air into the
-A refrigerator equipped with a control device for controlling the operation of the device
And the damper device opens and closes the cold air duct.
An open / close plate and a bias spring for biasing the open / close plate in the opening direction
And a heater for heating are wound around the austenite phase
Before heating to the original shape when heated above the transfer end temperature
The opening / closing plate is closed against the biasing force of the bias spring.
And a shape memory alloy coil spring.
The gold coil spring is arranged on the storage room side, and the control device is
The heater is energized to close the open / close plate.
It is characterized by the following .

Further, the present invention provides a cool air duct for guiding cool air cooled by a cooler to a storage room, a damper device for controlling the flow of cool air into the cool air duct, and a control device for controlling the operation of the damper device. The refrigerator includes a case having an opening communicating with the cool air duct, an opening and closing plate pivotally supported by the case to open and close the opening, and biasing the opening and closing plate in an opening direction. And a shape memory alloy coil spring for recovering the original shape when the heating heater is wound and heated to a temperature higher than the austenite phase transition end temperature and closing the opening / closing plate against the biasing force of the bias spring. The control device energizes the heater to close the open / close plate, and controls the temperature of the shape memory alloy coil spring in a state where the open / close plate is opened. It is to provide a refrigerator which is to flow a small current to the heater to maintain a more martensitic phase transition initiation temperature.

That is, as a driving source of the damper device, a shape memory alloy coil spring that undergoes a two-stage transformation of a mother phase (B2) → intermediate phase (R phase) → martensite phase (M phase) in the cooling process, and opposes this. The present invention provides a control method for preventing a force generated during heating of a shape memory alloy from being lowered even after 300,000 times opening / closing with respect to an initial value. In order to save power without energizing the heater more than necessary sometimes, and to quickly transform to the martensite phase during cooling, a small current is applied to the heater even during the transformation to change from the R phase or R phase to the M phase. Is maintained at about the temperature during the transformation and is not cooled to a low temperature state (that is, the Mf point).

Further, in the refrigerator of the present invention, after the control device closes the opening with the opening / closing plate, the temperature of the shape memory alloy coil spring exceeds the martensite phase transition starting temperature of the R phase transformation and the austenite phase transition. This is to reduce the duty ratio of the heater so as to maintain the temperature below the end temperature.

[0017]

According to the first aspect, the heater is energized when the opening / closing plate is closed , and stopped when the opening / closing plate is opened.
Since the metal alloy coil spring was arranged on the storage room side,
When the power is turned on, the cold air duct is closed.
This prevents the cooler from cooling the heater.
Wear.

According to the second aspect of the present invention, even when the opening / closing plate is opened (that is, when the shape memory alloy coil spring is cooled), a minute current is always supplied to the heater. The temperature can be maintained only during the phase transformation or at the intermediate stage from the R phase to the M phase, and the amount of generation force and strain of the shape memory alloy decreases less than the initial value after opening and closing 300,000 times or more. The durability of the device is dramatically increased. In addition, when the heater is energized, the required amount of heat is minimized, and the responsiveness of the switching operation is improved.

According to the third aspect, after the opening is closed by the opening / closing plate (ie, after the shape memory alloy coil spring is heated to the point Af or higher), the power supply rate to the heater is reduced. The temperature of the shape memory alloy coil spring can be maintained above the Ms point of the R-phase transformation and below the Af point,
The power consumption of the heater can be reduced and the temperature drop characteristic during cooling of the shape memory alloy coil spring can be improved as compared with the related art.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional side view of a refrigerator, and FIG. 2 is an enlarged sectional view around a damper device in a state where the damper device of the present invention is arranged at an inlet portion of a cold air duct of a refrigerator.
FIG. 3 is an exploded perspective view of the damper device, FIG. 4 is a plan view of the damper device, FIG. 5 is a stress-temperature characteristic diagram of the shape memory alloy coil spring, and FIGS. FIG. 8 is an electric circuit diagram showing an embodiment and another embodiment, and FIG. 8 is a time chart showing a state of energization to a compressor, a blower and a heater controlled by a control device and a temperature change of a shape memory alloy coil spring.

In FIG. 1, reference numeral 1 denotes a household refrigerator, which is a heat-insulating box 2 having a front opening and constituting a main body thereof.
And doors 3, 4, and 5 for closing the opening of the box. The door 3 is a revolving door corresponding to a refrigerator compartment 13 described later, the doors 4 and 5 are draw-out doors, the door 4 corresponds to the freezing compartment 14, and the door 5 corresponds to the vegetable compartment 15. ing.

Reference numerals 11 and 12 denote horizontal partition walls for partitioning the interior of the heat insulating box 2 into three stages of upper, middle and lower. In this embodiment, the partition walls 11 are used.
The refrigerator compartment 13 is cooled to a temperature where the food does not freeze (for example, about 3 ° C.), the freezer compartment 14 is cooled above the partition wall 12 to the freezing temperature (for example, about −20 ° C.), and the refrigerator is cooled below. The vegetable room 15 is cooled to a temperature slightly higher than the room temperature and suitable for storing vegetables (for example, about 7 ° C.). In addition, a container 16 for storing frozen food is provided on the door 4,
A container 17 for storing vegetables is attached to the door 5.

A partition plate 18 is disposed at the back of the freezer compartment 14. Behind the partition plate 18, a plate fin type evaporator 19 as a cooler and a blower 20 such as a propeller fan are provided.
Is formed.

Reference numeral 22 denotes a freezing air duct for supplying the cool air cooled by the evaporator 19 from the outlet 22A to the freezing compartment 14, and 23 denotes a cool air that passes through the horizontal partition wall 11 and is cooled by the evaporator 19. Is a refrigeration cool air duct for supplying refrigeration to the refrigeration compartment 13, and 24 is a distribution chill air duct that communicates with the refrigeration cold air duct 23 and distributes the cool air from the outlets 24A and 24B to the refrigeration compartment. Reference numeral 25 denotes a damper device, which is a so-called shape memory damper, which is disposed at a connection portion between the refrigeration cool air duct 23 and the distribution cool air duct 24.

A machine room 33 in which a compressor 31 and an evaporating dish 32 are arranged is formed below and behind the heat insulating box 2. Reference numeral 35 denotes a dew tray disposed below the evaporator 19, and reference numeral 36 denotes a defrosting heater such as a quartz glass tube heater or a Vycor tube heater disposed between the dew tray 35 and the evaporator 19. In addition, a platinum-based ceramic deodorizing catalyst is laminated and fired on the surface of the glass tube of the heater 36 for defrosting. This defrost heater 36 allows the compressor 3
At the time of the operation 1 (that is, at the time of the cooling operation), the odor component of the cool air including the odor component returning below the evaporator 19 is adsorbed,
Heat can be exchanged with the evaporator as clean cool air, and when the defrost heater is operated (that is, during the defrost operation), the adsorbed odor component is oxidized and decomposed with a platinum-based catalyst to form a catalyst layer. Activation and clean air can be generated.

Reference numeral 37 denotes the horizontal partition wall 12 extending from the cold air inlet 37A formed at the front of the lower surface of the horizontal partition 12 to the return port 37B formed at the rear of the partition 12 and below the evaporator. It is a cold air return passage extending inside in the front-rear direction. Reference numeral 38 denotes a water distribution pipe that guides defrost water from the dew receiving tray 35 to the evaporating tray 32.

The damper device 25 is provided with the cold air duct 2 for distribution.
Transparent resin case 42 having opening 41 communicating with 4
An opening / closing plate 43 pivotally supported by the case 42 to open and close the opening 41, a bias spring 44 for urging the opening / closing plate 43 in the opening direction, and a heater 45 such as a Kanthal heater for heating are wound. When heated to a temperature equal to or higher than the austenite phase transition end temperature (Af point), the original shape memorized is restored, and the open / close plate 43 is pressed against the biasing force of the bias spring 44.
And a shape memory alloy coil spring 46 that closes off.

The case 42 includes a substrate 51 and a cover 52. The substrate 51 includes an opening 41, a through hole 53 facing a part of the opening / closing plate 43, a rib 54 formed in a peripheral portion of the through hole to support the opening / closing plate 43, and two holes formed in a cover 52. Two insertion holes 55 for inserting the claws 58,
Fixing part 5 for fixing one end of shape memory alloy coil spring 46
6 and a fixing portion 57 for fixing one end of the bias spring 44. The cover 52 has a container shape with one surface opened, and has two claw portions 58 formed on a part of the periphery of the opening, and a hole 59 for taking in air is formed on one surface.

The opening / closing plate 43 includes two shafts 61 supported by the ribs 54 of the substrate 51, a fixing portion 62 for fixing the other end of the shape memory alloy coil spring 46, and a fixing portion for fixing the other end of the bias spring 44. A portion 63 and a sealing member 64 such as polystyrene foam for sealing the opening 41 and the opening / closing plate 43 when the opening 41 is closed.

Incidentally, both ends of the shape memory alloy coil spring 46 are fixed to fixing portions 56 and 62 via fixing members 65 with tools 60 such as screws. A fixed terminal 67 for connecting one end of the heater 45 and connecting a lead wire 66 is attached to each fixing member 65.
Is electrically connected to the fixed terminal 67 by crimp welding. In FIG. 3, the shape memory alloy coil spring 4
6 and both ends of the bias spring 44 are respectively attached to the opening / closing plate 43 and the case 42. However, as compared with FIG. 9 of the prior art, the way of applying the biasing force of each spring is opposite to that of the present invention and the conventional example. Has become.

Next, the shape memory alloy coil spring 4 of the present invention will be described.
The stress-temperature characteristics of No. 6 will be briefly described. Generally, an intermediate phase (so-called land-hedral phase (hereinafter simply referred to as R phase)) and a martensite phase (hereinafter simply referred to as M phase) in a cooling process having a large hysteresis width as shown in FIG.
Shape memory alloy having the property of transforming in two stages (particularly R
An alloy having a phase and a bias load (bias spring) are used), and the phase transformation by cooling and heating is used in the order of B2 → R → M → B2. In the present invention, specific examples thereof include an Af point of 70 ° C., an austenite phase transition onset temperature As (hereinafter simply referred to as an As point) of 53 ° C.,
Martensite phase transition onset temperature Ms '(hereinafter simply referred to as Ms' point) 55 ° C. in R phase, martensite phase transition end temperature Mf '(hereinafter simply Mf' point) in R phase 46 ° C. Martensite phase transition onset temperature Ms (hereinafter simply referred to as Ms point) 9 ° C. Martensite phase transition end temperature M in M phase
f (hereinafter simply referred to as Mf point) A shape memory alloy (TiNi alloy) in a temperature range around -18 ° C is used. In particular, it is a TiNi alloy having 45.2% by weight of Ti and 54.8% by weight of Ni.

In FIG. 6 showing the first embodiment of the control device S, reference numeral 71 denotes a freezer compartment temperature sensor (hereinafter referred to as an F sensor) 72 for detecting the temperature of the freezer compartment 14 and a refrigerator compartment temperature for detecting the temperature of the refrigerator compartment. It is a microcomputer as control means for controlling energization to the compressor 31, the blower 20, and the heater 45 based on a temperature detection signal from a sensor (hereinafter referred to as an R sensor) 73. One output port of the control means 71 is connected to the base of a transistor 75 via a resistor 74. The emitter is grounded, the collector is connected to a DC power supply (for example, 12 V) 76 via the heater 45, and grounded via a bias resistor 77.

When the temperature of the refrigerator compartment detected by the R sensor 73 is equal to or lower than the set lower limit temperature of the refrigerator compartment, the control means 71 outputs a high level signal (hereinafter referred to as H signal) from an output port to close the damper device 25. Output transistor 75
, And approximately 12 V is applied to the heater 45.

In the refrigerator mounting experiment, when the heater 45 was set to a wire diameter of φ0.11 mm, a heater length of about 1.6 m, and a resistance value of about 190Ω, the calorific value was 0.75 W / h.
The temperature of the shape memory alloy coil spring 46 stabilizes at about 90 ° C. higher than the Af point (70 ° C.). Case) closed with margin. This is also due to the fact that the lower limit temperature when the coil spring described later is cooled is higher than the conventional temperature.

When the temperature of the refrigerating compartment detected by the R sensor 73 is equal to or higher than the set upper limit temperature of the refrigerating compartment, the control means 71 outputs a low level signal (hereinafter referred to as an L signal) from an output port to open the damper device 25. The transistor 75 is turned off, the transistor 75 is turned off, and about 12 V is applied to a series circuit of the heater 45 and the bias resistor 77 to lower the temperature of the shape memory alloy coil spring 46 to near the Ms point (9 ° C.). Fully open.

In the refrigerator mounting experiment, the bias resistor 7
By setting 7 to 160Ω, the calorific value of the heater 45 becomes about 0.2 W / h (about 27% of the H signal output), and can be maintained at about 10 ° C. even when the minimum temperature is reached. The opening / closing plate 43 could be fully opened. At the time of cooling, the temperature of the shape memory alloy coil spring 46 is reduced only to a temperature near the Ms point, so that the power consumption to the heater is completely stopped and the opening / closing plate is closed. Although the power increased, it could be opened in a short time. Further, since the temperature is reduced only to about 10 ° C., the shape memory alloy coil spring 46 can be used only in the R phase (ie, R → B2, B2 → R transformation). Device 2
5 can improve the thermal cycle fatigue characteristics and the repetition characteristics. In the experiment, when the change in the contraction force of the coil spring 46 was measured by changing the number of times of opening and closing with and without the bias resistor 77, the decrease in the contraction force was smaller when the bias resistor 77 was provided. Was.

On the other hand, the difference between FIG. 7 showing the second embodiment of the control device S and FIG. 6 described above is that there is no bias resistor in FIG. Since the signal is different from that of the signal of FIG.

When the temperature of the refrigerator compartment detected by the R sensor 73 is equal to or lower than the set lower limit temperature of the refrigerator compartment, the control means 78 outputs an H signal from the output port to close the damper device 25 and makes the transistor 75 conductive. , Heater 1
Apply 2V.

When the temperature of the refrigerating compartment detected by the R sensor 73 is equal to or higher than the upper limit temperature of the refrigerating compartment, the control means 78 outputs H from the output port to open the damper device 25.
The signal and the L signal are output alternately (intermittently), the transistor 75 is intermittently turned on, and a DC voltage (about 12 V) is intermittently supplied to the heater 45.

For example, an H signal is output from the output port of the control means 78 for 4 seconds, and an L signal is output for 11 seconds, so that the heating value of the heater 45 is set to about 0.2 W as described above. Even when the lowest temperature is reached, the temperature near the Ms point (about 10
° C), and the opening / closing plate 43 could be opened without any trouble. This could be opened in a shorter time than in the conventional case of cooling and closing.

That is, the temperature of the shape memory alloy coil spring 46 is heated to the point Af or higher by continuously energizing the heater 45 by the control means 78, and the temperature of the shape memory alloy coil spring 46 is increased to around the Ms point by intermittent energization. To make it stable.

In the above configuration, the heater 45 is energized when the opening and closing plate 43 is closed, and the energization rate to the heater 45 is decreased when the opening and closing plate 43 is opened. Can be improved.

Further, even when the open / close plate 43 is opened (ie, when the shape memory alloy coil spring 46 is cooled), the heater 4
5, the temperature of the shape memory alloy coil spring 46 can be maintained only at the R-phase transformation or at the intermediate stage from the R-phase to the M-phase.
The contraction force and distortion amount of the shape memory alloy coil spring 46 are set to 3
The amount of decrease in the value after opening and closing for more than 100,000 times with respect to the initial value is reduced, and the durability of the damper device 25 is dramatically increased. In addition, when the heater 45 is energized, the required amount of heat generation is minimized, and the responsiveness of the opening / closing operation is improved.

Further, after the opening 41 is closed by the opening / closing plate 43 (that is, after the shape memory alloy coil spring 46 is heated to the point Af or higher), the duty ratio of the heater 45 is reduced. The temperature of the shape memory alloy coil spring 46 can be maintained above the Ms point of the R-phase transformation and below the Af point, so that the power consumption of the heater 45 can be reduced and the temperature drop characteristics of the shape memory alloy coil spring 46 during cooling can be reduced. Can also be improved.

Finally, a third embodiment of the control device will be described with reference to FIG. The control means in the third embodiment stops the energization of the heater 45 when the opening and closing plate 43 is opened, and continuously energizes the heater 45 at the beginning when the opening and closing plate 43 is closed, so that the temperature of the shape memory alloy coil spring 46 exceeds the point Af. After that, the signal is controlled so that the power supply to the heater 45 is switched to the intermittent power supply. As a starting point of the switching to the intermittent energization, a state in which the temperature of the shape memory alloy coil spring changes when a predetermined time (for example, 2 minutes) has passed after the temperature of the freezing compartment 14 has fallen below the lower limit temperature of the freezing compartment. Is shown in FIG. The end of the intermittent energization is when the temperature of the freezer reaches or exceeds the set upper limit temperature.

According to this control method, when closing the open / close plate 43 (ie, when heating the shape memory alloy coil spring).
Can be reduced as compared with the control method of the first embodiment, and the upper limit of the temperature rise of the shape memory alloy coil spring 46 can be reduced. For this reason, the temperature range to be lowered when the opening / closing plate 43 is opened (that is, when the shape memory alloy coil spring is cooled) is reduced, and the time required for fully opening the opening / closing plate 43 is further shortened as compared with the first and second embodiments. The opening and closing operation of the opening and closing plate can be performed quickly. It is also possible to maintain the temperature after the temperature of the shape memory alloy coil spring 46 reaches the point Af or higher at a temperature between the points Af and Ms.

[0047]

According to the first aspect, a shape memory alloy coil is provided.
The spring is arranged on the storage room side, and the heater is energized to open and close the
The opening and closing plate closes when the power is turned on.
The cool air of the cooler does not reach the heater,
The data can be prevented from being exposed to cool air on the cooler side.

According to the second aspect of the invention, even when the open / close plate is opened (that is, when the shape memory alloy coil spring is cooled), a minute current is always supplied to the heater. It is possible to maintain only the phase transformation or the temperature in the middle of the transition from the R phase to the M phase, and to reduce the generation force and strain of the shape memory alloy from the initial value after opening and closing more than 300,000 times. As a result, the durability is dramatically increased. In addition, when the heater is energized, the required amount of heat is minimized, and the responsiveness of the switching operation is improved.

According to the third aspect, after the opening is closed by the opening / closing plate (that is, after the shape memory alloy coil spring is heated to the point Af or higher), the energization rate to the heater is reduced. The temperature of the shape memory alloy coil spring can be maintained above the Ms point of the R-phase transformation and below the Af point,
The power consumption of the heater can be reduced and the temperature drop characteristic during cooling of the shape memory alloy coil spring can be improved as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a refrigerator.

FIG. 2 is an enlarged sectional view around the damper device in a state where the damper device according to the present invention is arranged at an inlet portion of a cold air duct of a refrigerator.

FIG. 3 is an exploded perspective view of the damper device.

FIG. 4 is a plan view of the damper device.

FIG. 5 is a stress-temperature characteristic diagram of a shape memory alloy coil spring.

FIG. 6 is an electric circuit diagram showing a first embodiment of the control device.

FIG. 7 is an electric circuit diagram showing another embodiment of the control device.

FIG. 8 is a time chart showing a state of energization of a compressor, a blower, and a heater controlled by a control device and a temperature change of a shape memory alloy coil spring.

FIG. 9 is a view corresponding to FIG. 2 showing a conventional damper device.

FIG. 10 is an electric circuit diagram showing a conventional control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigerator 24 Distribution cool air duct (Cool air duct) 25 Damper device 41 Opening 42 Case 43 Opening / closing plate 44 Bias spring 45 Heater 46 Shape memory alloy coil spring (SMA coil) S Control device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-113258 (JP, A) JP-A-60-207885 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25D 17/08 F03G 7/06

Claims (3)

(57) [Claims] 1. A refrigerator comprising: a cool air duct for guiding cool air cooled by a cooler to a storage room; a damper device for controlling the flow of cool air into the cool air duct; and a control device for controlling the operation of the damper device. In the damper device, an opening / closing plate for opening and closing the cold air duct , a bias spring for urging the opening / closing plate in an opening direction, and a heater for heating are wound and heated to a temperature equal to or higher than the austenite phase transition end temperature. A shape memory alloy coil spring that closes the open / close plate against the biasing force of the bias spring by restoring its original shape, and the shape memory alloy coil spring is disposed on the storage chamber side,
The refrigerator is characterized in that the control device energizes the heater to close the opening / closing plate. 2. A refrigerator comprising: a cool air duct for guiding cool air cooled by a cooler to a storage room; a damper device for controlling the flow of cool air into the cool air duct; and a control device for controlling the operation of the damper device. In the case, the damper device has a case having an opening communicating with the cold air duct,
An opening / closing plate rotatably supported by the case to open and close the opening, a bias spring for urging the opening / closing plate in an opening direction, and a heater for heating are heated around the austenite phase transition end temperature or higher. Sometimes a shape memory alloy coil spring that recovers to its original shape and closes the open / close plate against the biasing force of the bias spring, and the controller energizes the heater to close the open / close plate. A refrigerator configured to constantly supply a minute current to the heater so as to maintain the temperature of the shape memory alloy coil spring at or above the martensite phase transition start temperature in a state where the opening / closing plate is opened. 3. A refrigerator comprising: a cool air duct for guiding cool air cooled by a cooler to a storage room; a damper device for controlling the flow of cool air into the cool air duct; and a control device for controlling the operation of the damper device. In the case, the damper device has a case having an opening communicating with the cold air duct,
An opening / closing plate rotatably supported by the case to open and close the opening, a bias spring for urging the opening / closing plate in an opening direction, and a heater for heating are heated around the austenite phase transition end temperature or higher. Sometimes a shape memory alloy coil spring that recovers to its original shape and closes the open / close plate against the biasing force of the bias spring, and the controller energizes the heater to close the open / close plate. After the opening is closed by the opening / closing plate, power is supplied to the heater so that the temperature of the shape memory alloy coil spring is maintained at a temperature higher than the martensitic phase transition start temperature of the R phase transformation and lower than the austenite phase transition end temperature. A refrigerator characterized by lowering the rate.