JPS6042571A - Freezing refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a refrigerator-freezer and, in particular, to a refrigerator that reliably prevents the temperature inside the freezer from rising by B degrees during defrosting, despite having a simple configuration. Regarding the refrigerator-freezer that has been made possible.

[Technical background of the invention and its problems]

Conventionally, in a refrigerator-freezer equipped with a freezer compartment and a refrigerator compartment, the method for cooling the freezer compartment has been to directly cool the freezer compartment.
One is the direct cooling method in which a cooler is installed, and the other is the forced cold convection method in which a cooling room with a cooler is installed inside the freezer compartment and the air inside the freezer is circulated through the cooling room using a convection fan. There is a so-called intercooling method that uses a cold air forced convection method, which has the advantage of uniformly cooling the inside of the freezer compartment in a short time.

By the way, even in the above-mentioned intercooling type refrigerator-freezer, it is still necessary to remove frost from the surface of the cooler installed inside the cooling chamber at any time.

7 Generally, such defrosting from the surface of the cooler is carried out by heating the cooler with an electric heater for defrosting, but in conventional intercooled refrigerator-freezers, when defrosting Convection occurs between the freezing compartment and the cooling compartment, and as a result, the temperature within the freezing compartment increases, which poses a problem in that food and the like cannot be stored in the freezing compartment.

Therefore, in order to eliminate such problems, recently a rotatable damper plate was installed in the communication path connecting the freezing room and the cooling room to open and close this communication path, and the damper plate was closed during defrosting. A refrigerator-freezer has been proposed that prevents convection between the freezer compartment and the cooling compartment by controlling the temperature of the refrigerator, thereby suppressing the rise in temperature within the freezer compartment during defrosting. ``In the case where a damper plate is provided as described above, a driving mechanism using an electromagnetic plunger or a shape memory alloy material is used as a means for driving the damper plate.

However, the refrigerator-freezer equipped with a damper plate and a drive mechanism using a shape memory alloy material as described above has the following problems.

That is, in order to heat the shape memory alloy material above its transformation point temperature in a short period of time, an electric heater for controlling the damper is required. Using a large-capacity electric heater like this allows the damper plate to be closed in a short time, but on the other hand, the damper plate is heated more than necessary during the defrosting period, and as a result, the temperature inside the freezer compartment increases due to the above heating effect. There was a problem. Therefore, it is possible to use a low-capacity electric heater for controlling the damper, but in this case, it takes a long time for the tamper plate to close.
During this time, there is a problem that air heated by the defrosting electric heater flows into the freezing chamber.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to operate the damper plate reliably and in a short time with low electric capacity using a drive mechanism using a shape memory alloy material. To provide a refrigerator-freezer which can reliably prevent a temperature rise in a freezer compartment during defrosting.

[Summary of the invention]

The present invention provides the forced circulation and supply of refrigerant to the cooler during defrosting, in which air in the freezer is forced to circulate through the cooling chamber in which the cooler is housed, and frost adhering to the cooler is removed. In the refrigerator-freezer, the cooler is heated by a defrosting electric heater, and the damper is provided in a communication path that connects the freezing compartment and the cooling compartment, and is rotatable to open and close the communication path. A drive mechanism that is provided near the damper plate and is mainly made of a shape memory alloy material that opens and controls the damper plate by changes in mechanical constants that occur at the transformation point temperature, and this drive mechanism. a damper control electric heater that selectively heats the shape memory alloy material; and a damper control electric heater that is energized prior to energizing the defrosting electric heater during defrosting and energized at least during the defrosting period. a control circuit, a temperature sensor provided near the shape memory alloy material, and an electric heater for damper control interposed between the control circuit and the electric heater for controlling the damper in accordance with the output of the temperature sensor. The present invention is characterized in that it includes a temperature control circuit that controls the temperature of the shape memory alloy material to a value slightly exceeding the transformation point temperature by controlling on/off the energization of the shape memory alloy material.

〔Effect of the invention〕

With the above configuration, at the time of defrosting, the damper control electric heater is first energized, and after a predetermined time period, the defrosting electric heater is energized. Then, when the electric heater for damper control is energized as described above, the temperature of the shape memory alloy material increases gradually, and finally reaches its transformation point. In this way, when the temperature rises to the transformation point, the shape memory alloy material is mechanically displaced, and this displacement brings the damper plate into the closed state, thereby closing the passage between the freezing chamber and the cooling chamber. In this case, a temperature control circuit that operates in response to the temperature sensor is installed in the input line of the electric heater for damper control.
Thereafter, the input to the damper control electric heater is controlled by this temperature control circuit to a value that allows the temperature of the shape memory alloy material to be slightly higher than the transformation point temperature. This means that
It has the following meaning: That is, even if a large-capacity electric heater ζ for damper control is used, this electric heater will not be energized to form an atmosphere with a temperature slightly higher than the transformation point. In other words, even if a large-capacity damper control electric heater is used, the tamper plate and the like will not be heated more than necessary.

Therefore, it is possible to prevent the temperature of the freezing compartment from rising, which tends to occur when a large-capacity damper control electric heater is used.

In addition, since a large-capacity electric heater for damper control can be used, the damper plate can be switched to the closed state in a short time, and furthermore, the damper control Combined with the fact that the electric heater is energized, it is possible to reliably prevent the temperature of the freezer compartment from rising during defrosting.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which the present invention is applied to a refrigerator-freezer in which a freezer compartment and a refrigerator compartment are cooled by separate coolers.

In the figure, 1 is a refrigerator/freezer housing, and this housing 1
is a member that includes a heat insulating material 2 and is formed vertically. The interior of the housing 1 is divided into upper and lower parts by a partition wall 3, and the presence of the partition wall 3 forms a freezer compartment 4 in the upper part and a refrigerating compartment 5 in the lower part. The side walls of the freezer compartment 4 and the refrigerator compartment 5 located on the same side are respectively formed into doors 6.7 that can be opened and closed.

Thus, a cooling chamber 9 is formed in the back wall 8 of the freezer compartment 4, and the upper end of this cooling chamber 9 is located above the inner surface of the back wall 8 through a passage 110 formed in the back wall 8. The cooling chamber 9 communicates with an open discharge port 11, and the lower end of the cooling chamber 9 communicates with a suction port 13 that opens at a position below the inner surface of the back wall 8 via a passage 12 formed in the back wall 8. A cooler 14 is installed within the cooling chamber 9. A sheathed heater 15 is attached to the cooler 14 and is energized only during defrosting.

Further, a convection fan 16 is installed inside the discharge port 11, and a damper mechanism 17 is installed inside the passage 10. On the other hand, a cooler 18 for cooling the inside of the refrigerator compartment 5 is installed at a lower position within the refrigerator compartment 5 . and,
The cooler 18 and the cooler 14 are connected to the compressor 1
9 and a condenser 20. This freezing cycle is controlled by an operation control device (not shown). That is, the operation control device controls the temperatures in the freezer compartment 4 and the refrigerator compartment 5 to the set values by controlling the compressor 19 on and off.

Specifically, the damper mechanism 17 is constructed as shown in FIG. 2.

That is, in this embodiment, a support plate 22 rotatably supports one end side of the damper plate 21 on the inner surface of the passage 10.
is installed. In addition, a support plate 22 is provided on the inner surface of the passage 10.
A support plate 24 having a locking wall 23 capable of locking the other end of the damper plate 21 is mounted at a position facing the damper plate 21 . A damper drive mechanism 25 is provided at a position below the damper plate 21 on the inner surface of the support plate 22. This damper drive mechanism 25 includes a heating plate 2 whose one end side is fixed to a support plate 22.
6, a relatively large-capacity electric heater 27 fixed to the lower surface of the heating plate 26 in an electrically insulated state, and the electric heater 2
A temperature sensor 28 fixed near 7 and a heating plate 26
The drive member 29 has one end fixed to the upper surface of the drive member 29. The drive member 29 is made of a shape memory alloy material and is formed into an elongated plate shape, and when the temperature is below the transformation point, it is displaced in a dogleg shape as shown in FIG. The damper plate 21 is kept open by pushing up the plate 21, and when the temperature exceeds the transformation temperature, the damper plate 21 is displaced linearly and rotated downward as shown in FIG. 2(b). The damper plate 21 is moved to keep the damper plate 21 closed.

Therefore, both ends of the sheathed heater 15, both ends of the electric heater 27, and the output end of the temperature sensor 28 are connected to the third
It is connected to a defrosting control device 31 shown in the figure.

The defrosting control device 1f31 integrates the period during which the motor 32 of the compressor 19 was operated using an integration counter 33, and causes the counter 33 to send out an output signal every time this integrated value reaches, for example, 8 hours. . The output of the counter 33 is given as an operation stop signal to the operation control device and as an ON control signal to the switching circuit 34 which supplies input to the electric heater 27. It is provided as an ON control signal and an input signal to the timer circuit 37. The switching circuit 34 is configured to send an output for, for example, 40 minutes when the output of the integration counter 34 is applied. This output is then given to the electric heater 27 via the temperature control circuit 38. The temperature control circuit 38 inputs the output of the temperature sensor 28 and controls the input of the electric heater 27 on and off so that the temperature of the drive member 29 is slightly higher than its transformation point. It is configured. Further, the delay time of the delay circuit 35 is set to, for example, 5 minutes. The switching circuit 36 controls the input to the sheathed heater 15. Further, the output of the timer circuit 37 is provided as a reset signal for the counter 33. Note that the time limit of the timer circuit 37 is set to, for example, 30 minutes.

This configuration works as follows.

That is, while no output is being sent from the integration counter 33, the operation control device operates and normal refrigeration operation is performed. At this time, the damper plate 21 is kept open as shown in FIG. 2(a), and the convection fan 16 is kept in continuous operation. By controlling the motor 32 of the compressor 19 on and off, the temperatures in the freezer compartment 4 and the refrigerator compartment 5 are maintained at set values.

When the cumulative operating period of the motor 32 of the compressor 19 reaches 8 hours, the cumulative counter 33 outputs an output. As a result, the operation of the operation control device is stopped, the supply of refrigerant to the cooler 14, 18 is stopped, and the operation of the convection fan 16 is also stopped. When the output from the integration counter 33h is sent out as described above, the switching circuit 34 is activated and current flows through the electric heater 27.

Therefore, the drive member 29 is rapidly heated as shown in FIG. . When the driving member 29 is heated to its transformation point T, the driving member 29 is linearly displaced as shown in FIG. 2(b), and as a result, the damper plate 21 is brought into a closed state. . When heated to such a temperature T, the temperature control circuit 38 operates in response to the output of the temperature sensor 28, and controls the electric heater 270 input so as to maintain the temperature slightly higher than the transformation point temperature. Therefore, from now on, the temperature of the driving member 29 maintains a linear state, that is,
It is maintained at a nearly constant temperature that allows it to remain closed. For this reason, there is no fear that the drive member and damper plate will be heated more than necessary, unlike in the conventional case shown by the broken line in FIG. The switching circuit 36 operates after the time limit set by the delay circuit 35, and the sheathed heater 15 is thereby energized. At this point, the damper plate 21 is completely closed. The heat generated by the sheathed heater 15 raises the temperatures in the cooler 14 and the cooling chamber 9, which melts the frost adhering to the surface of the cooler 140 and removes it in the form of water droplets. Note that this water droplet is discharged to the outside by a known means. In this case, when the temperature inside the cooling chamber 9 rises, the warm air inside the cooling chamber 9 tries to flow into the refrigerator v4 by convection. However, since the passage 10 is blocked by the damper plate 21, no convection path is formed, and as a result, even if the temperature inside the cooling chamber 9 rises, the temperature inside the freezing chamber 4 will not rise. Therefore, even if defrosting is performed while the food or the like is still stored in the freezer compartment 4, the quality of the food or the like will not be degraded.

Then, when the time limit set in the timer circuit 37 has elapsed since the start of energizing the sheathed heater 15, an output is sent from the timer circuit 37, and as a result, the integration counter 33 is reset.

Therefore, at the above-mentioned time point, the power supply to the sheathed heater 15 is stopped, and the supply of the operation stop signal to the operation control device is also stopped. However, in this embodiment, the electric heater 27 is energized until five minutes have elapsed since the integration counter 33 was reset. Therefore, a short time after this point, the drive member 29 returns to the state shown in FIG. 2(a), and eventually the refrigeration operation starts again from this point, and the above-described operation is repeated thereafter. That is, in this embodiment, tl shown in FIG. 4 is the period required to close the damper plate 21, and t2 is the period required to close the defrosting electric heater 15.
t3 is an extended period during which the damper plate 21 is closed.

In this way, since the communication path between the freezing compartment 4 and the cooling compartment 9 can be blocked by the damper plate 21 during defrosting, it is possible to prevent the temperature inside the freezing compartment 4 from rising, and prevent food from entering the freezing compartment 4. It is possible to defrost the food without degrading the quality of the food, etc., even if the food is stored therein. Further, the electric heater 27 for heating the shape memory alloy material that drives the damper plate 21 is energized from before the defrosting electric heater 15 is energized to during the defrosting period, and the shape memory alloy material heating electric heater 27 is energized. Since the input to the electric heater 27 is controlled so that the temperature of the material is maintained at a value slightly higher than the transformation point,
A large electric heater 27 can be used, thereby shortening the time required for the damper plate 21 to close while the damper control heater does not have an adverse effect during defrosting. As a result, the aforementioned effects can be obtained.

Note that the present invention is not limited to the embodiments described above, and can be modified in various ways. That is, in the above-mentioned embodiment, a bidirectional shape memory alloy material is used as a member for rotationally driving the damper plate, but the material is not limited to this, and for example, a unidirectional shape memory alloy material is used as shown in FIG. A rotation drive mechanism that combines a shape memory alloy material and an electric heater may also be used. That is, a support plate 22a that rotatably supports one end of the damper plate 21 is mounted on the inner surface of the passage 10, and the damper plate 21 is offset in the opening direction between the support plate 22a and the tip of the damper plate 21. Spring 41 to always apply force
Stretch it. Further, a support plate 24a provided with a locking wall 23 capable of locking the other end side of the damper plate 21 is attached to a position facing the support plate 22a on the inner surface of the passage 10, and this support plate 24a
A coil spring 42 made of a unidirectional shape memory alloy material is stretched between the damper plate 21 and the damper plate 21 . And support plate 2
A damper drive mechanism 43 is provided at a position below the coil spring 42 on the inner surface of 4a. This damper drive mechanism 43 includes a heating plate 44 whose one end side is fixed to the support plate 24a as in the previous embodiment, an electric heater 45 which is fixed to the upper surface of this heating plate 44 in an electrically insulated state, and It is composed of a temperature sensor 46 fixed to the top surface. Then, the electric heater 45 is energized by a circuit corresponding to the switching circuit 34 and temperature control circuit 38 in the embodiment.

Therefore, with such a configuration, the coil spring 2
When the temperature is below the transformation point, the damper plate 21 opens under the force of the spring 41. When the coil spring 42 is heated above the transformation point by the electric heater 45, the coil spring 42 contracts and the damper plate 21 opens. Controlled closed. Therefore, the same effects as in the above embodiment can be expected.

It goes without saying that the present invention can also be applied to a refrigerator in which a single cooler cools both the freezer compartment and the refrigerator, or a refrigerator in which the freezer compartment is provided with a rapid cooling cooler. Furthermore, the defrosting control device may be operated by the output of the frost thickness detector.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a refrigerator-freezer according to an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view showing only the main parts of the refrigerator-freezer, and Fig. 3 is a longitudinal cross-sectional view showing only the main parts of the refrigerator-freezer. A configuration diagram of the frost control device, Fig. 4 is a diagram for explaining the operation of the main parts, Fig. 5
The figure is an explanatory diagram of the configuration of main parts in another embodiment of the present invention. 1... Freezer-refrigerator housing, 4... Freezing room, 5... Refrigerator room, 9... Cooling room, 10.12... Connection path, 14
．． 18...Cooler, 15...Sheathed heater, 17.
...Damper mechanism, 21...Damper plate, 25.43...
- Damper drive mechanism, 31...defrosting control device. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 (a) (b) Figure 3 Figure 4 Figure 5 j

Claims (2)

[Claims] (1) The air in the freezing room is forced to circulate through the cooling room where the cooler is housed, and the frost adhering to the cooler is removed. During defrosting, the air is forced to circulate and to the cooler. In a refrigerator-freezer in which the refrigerant supply is stopped and the cooler is heated by a defrosting electric heater, a rotation is provided in a communication path that connects the freezing compartment and the cooling compartment to open the communication path. A movable damper plate, a drive mechanism mainly made of a shape memory alloy material that is provided near the damper plate and controls the opening and closing of the damper plate by changes in mechanical constants that occur at the transformation point temperature; a damper control electric heater that selectively heats the shape memory alloy material of the drive mechanism; and a damper control electric heater that energizes the damper control electric heater prior to energizing the defrosting electric heater during defrosting and at least during the defrosting period. a control circuit that is energized; a temperature sensor provided near the shape memory alloy material;
The temperature of the shape memory alloy material is adjusted to the transformation point by controlling the energization of the damper control electric heater on and off in accordance with the output of the temperature sensor, which is inserted between the In circuit and the damper control electric heater. A refrigerator-freezer characterized by comprising a temperature control circuit that controls the temperature to a value slightly exceeding the temperature. (2) The control circuit is configured to energize the damper control electric heater for a predetermined period even after energization to the defrosting electric heater is stopped. The refrigerator-freezer described in item 1.