JP2975878B2 - 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 for defrosting by heating a cooler with a heater.

[0002]

In a refrigerator of this kind, for example, a fan-cool type refrigerator, air (cold air) cooled by a cooler is circulated in a refrigerator by a fan to cool the refrigerator. . In this case, moisture contained in the air flowing through the cooler portion becomes frost and adheres to the cooler. Therefore, as is well known, a defrosting operation is performed by heating a cooler with a defrost heater. In this defrosting operation, for example, when the cumulative operation time of the compressor reaches a predetermined time, the defrost heater is energized, and the temperature of the cooler detected by the temperature sensor provided in the cooler reaches the predetermined temperature. It has been determined that the defrosting has been completed, and the defrosting heater has been controlled to be cut off.

[0003] However, even if the defrosting operation is performed at a predetermined timing, the amount of frost formed in the cooler fluctuates due to the amount of moisture in the air and the like. In some cases, the defrosting operation could not be completed at an appropriate time due to a change in the followability of the sensor. Such a tendency,
This is particularly noticeable in large refrigerators (large coolers).

Therefore, in recent years, as shown in FIG. 11, temperature sensors 2 and 3 are partially provided at two locations above the cooler 1. Among these temperature sensors 2 and 3, the temperature sensor 2 on the right side in the figure is configured to detect the air temperature (air temperature) around the cooler 1 (hereinafter, referred to as "air temperature sensor 2"), The amount of frost is large, and it is provided in a portion where frost tends to remain to the end during defrosting. On the other hand, the temperature sensor 3 on the left side of the figure is configured to directly detect the temperature of the cooler 1 (evaporation temperature) (hereinafter, referred to as “evaporation temperature sensor 3”). The defrost heater 4 is provided below the cooler 1.

In such a configuration, the control of the defrosting operation is as follows:
The defrosting operation is performed as shown in the flowchart of FIG. 12, and the defrosting operation is terminated when the air temperature sensor 3 detects a temperature of, for example, 13 ° C. or more, and the air temperature sensor 2 detects a temperature of, for example, 13 ° C. or more. It has become.

The reason why the defrosting operation is terminated when the two temperature sensors 2 and 3 detect the temperature equal to or higher than the predetermined temperature is as follows. That is, FIG. 13 shows the detection temperature of the air temperature sensor 2 when the frost attached to the cooler 1 is completely melted (indicated by a dotted line in the figure) and the temperature of the evacuated temperature sensor 3 with respect to the amount of frost formed on the cooler 1. (Shown by a solid line in the figure). As can be seen from the figure, when the amount of frost is large, the air temperature rises earlier than the air temperature detected at a position in the cooler 1 where the amount of frost is relatively large. The temperature of the evaporator at the end of defrosting increases. Conversely, when the amount of frost is small, the air temperature rises earlier than the evaporator temperature, and the air temperature at the end of defrosting increases. On the other hand, when both the air temperature and the evaporating temperature are 13 ° C. or higher, the frost attached to the cooler 1 is completely melted regardless of the amount of frost, and the defrosting of the cooler 1 is performed. This can be performed reliably, and the defrosting time can be shortened.

[0007] However, such a conventional device requires two temperature sensors 2 and 3 and thus has a problem of high cost.

Therefore, an object of the present invention is to perform defrosting of a cooler by heating a heater, and it is possible to terminate an appropriate defrosting operation while detecting a defrosting end temperature. An object of the present invention is to provide a refrigerator capable of reducing the number of sensors.

[0009]

In performing defrosting of a cooler, conventionally, two temperature sensors are used in order to reliably know the defrost end timing regardless of the amount of frost formed on the cooler. I was On the other hand, if the amount of frost of the cooler can be estimated, the present inventor can detect the detected temperature of one temperature sensor based on the relationship between the follow-up property of the temperature sensor and the amount of frost that is known in advance. The idea that the control of the end of the defrost can be performed only by the inventor has been obtained. Here, the amount of frost formed by the cooler is affected by the level of humidity.In other words, the amount of frost is high in summer, such as during the rainy season, and the amount of frost is large. Is also reduced.
Then, in the refrigerator, for control of the cooling fan of the compressor, control of the heater for preventing the supercooling of the vegetable room, and the like, the detection of the room temperature around the refrigerator is originally performed. The present invention has been accomplished by paying attention to the fact that the amount of frost formed in the cooler can be estimated by the room temperature detected by the room temperature detecting means.

That is, the refrigerator according to the first aspect of the present invention includes a cooler and a fan that blows air through the cooler, and in a state where the cooling operation is stopped, the cooler is heated by a heater to perform defrosting. An air temperature sensor for detecting an air temperature, which is disposed in a portion of the cooler where the amount of air flow by the fan is likely to be frosty, and an air temperature sensor around the refrigerator. Room temperature detection means for detecting temperature, and control means for controlling the end of the defrosting operation, wherein the control means detects the temperature detected by the air temperature sensor when the room temperature detected by the room temperature detection means is equal to or higher than a predetermined temperature. When the temperature is equal to or higher than the first temperature, the defrosting operation is terminated, and when the room temperature detected by the room temperature detecting means is lower than the predetermined temperature, the temperature detected by the air temperature sensor is higher than the first temperature. And it is characterized in that it is configured to terminate defrosting operation when the above temperature.

A refrigerator according to a second aspect of the present invention includes a cooler and a fan that blows air through the cooler, and when the cooling operation is stopped, the cooler is heated by a heater to perform defrosting. An evaporating temperature sensor that is capable of performing a defrosting operation to be performed, is disposed in a portion of the cooler where the amount of air flow by the fan is small and hardly adheres to frost, and detects a temperature of the cooler; Room temperature detection means for detecting the ambient temperature, and control means for controlling the end of the defrosting operation, the control means, when the room temperature detected by the room temperature detection means is equal to or less than a predetermined temperature, by the evaluation temperature sensor The defrosting operation is terminated when the detected temperature is equal to or higher than the first temperature, and when the room temperature detected by the room temperature detecting means exceeds a predetermined temperature, the temperature detected by the evaluation temperature sensor is higher than the first temperature. And it is characterized in that it is configured to terminate defrosting operation when more than the second temperature.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment (corresponding to claim 1) of the present invention will be described below with reference to FIGS. First, FIG. 2 shows the overall configuration of the cooler 11.
The cooler 11 is provided in a cooler room 12 (see FIG. 6) formed at the rear of the refrigerator main body (not shown). The cooler 11 forms a pipe 13 connected to the refrigeration cycle in a meandering shape. 13 is provided with a large number of fins 14. The pipe 13 has a forward pipe 13a on the refrigerant inlet side and a return pipe 13b on the outlet side.
Are arranged side by side in parallel, and the return pipe 1
An accumulator 15 is connected to the outlet side of 3b.

As shown in FIG. 6, a fan 16 composed of a propeller fan is disposed above the cooler 11.
Is supplied to the freezing room and the refrigerating room, and the cold air in the freezing room and the refrigerating room is returned to the lower part of the cooler room 12, so that the cool air in the refrigerator is forcibly released. Is to be circulated.

In this case, as shown in FIG.
For example, when rotating in the direction of arrow A, the cool air in the cooler 11 has a tendency to be sucked into the fan 14 side as shown by arrow B, and the cool air flows almost evenly in the lower part of the cooler 11, but in the upper part. , The water flows toward the right side in the figure. Then, due to the bias of the air flow, frost adheres substantially uniformly to the entire lower part of the cooler 11, but the amount of frost tends to increase in the right part as compared to the left part as it goes to the upper part. There is.

In the cooler chamber 12, a defrost heater 17 composed of, for example, a glass tube heater is provided below the cooler 11, and the cooler 11 is operated by the defrost heater 17 from below. The defrosting operation is performed by being heated. A cover 18 is provided above the defrost heater 17 to prevent water drops falling from the cooler 11 from hitting the defrost heater 17 during the defrost operation. Although not shown, a well-known deodorizing member that adsorbs odorous components from the air in the refrigerator is attached to the lower surface of the cover 18, and the deodorizing member is regenerated by heating during the defrosting operation. Is performed together.

The cooler 11 is provided with an air temperature sensor 19 used for controlling the termination of the defrosting operation. The air temperature sensor 19 is made of, for example, a thermistor, and is mounted via a holder 20 on the upper right side of the cooler 11, that is, in the vicinity of a portion where the flow of cool air by the fan 16 is large and frost tends to be formed. . At this time, the holder 20 is formed of a heat insulating material, and is configured such that when the air temperature sensor 19 is fixed as shown in FIG. 3, the temperature sensor 19 and the cooler 11 are in a thermal non-contact state. ing. With this, this air temperature sensor 1
Numeral 9 detects the air temperature (air temperature) in the vicinity of a portion of the cooler 11 where frost tends to form.

FIG. 4 schematically shows an electrical configuration related to the defrost control of the cooler 11. The control circuit 21 as a control means is mainly constituted by a microcomputer. The control circuit 21 receives an air temperature detection signal from the air temperature sensor 19, and the defrost heater 17 and the compressor of the refrigeration cycle. The power cutoff control 22 is performed. Further, the control circuit 21
Is input with a room temperature detection signal from a room temperature sensor 23 as room temperature detecting means. This room temperature sensor 2
Numeral 3 is disposed in a control circuit accommodating portion provided in, for example, an upper back side portion of the refrigerator main body, and detects a temperature (room temperature) around the refrigerator main body. The detection signal of the room temperature sensor 23 is used for controlling the cooling fan of the compressor 22 and for controlling the heater for preventing the vegetable room from being excessively cooled.

The control circuit 21 starts the defrosting operation on the condition that the integrated operation time of the compressor 22 has reached a predetermined time, for example, by the software configuration. Is configured to terminate the defrosting operation based on the signal. At this time, as will be described in detail later in the description of the operation, when the detected temperature of the room temperature sensor 23 is equal to or higher than a predetermined temperature (for example, 12 ° C.), the control circuit 21 changes the temperature detected by the air temperature sensor 19 to the first temperature. (For example, 13
° C) or more, the defrosting operation is terminated, and when the temperature detected by the room temperature sensor 23 is lower than the predetermined temperature, the second temperature (for example, 15 ° C) in which the temperature detected by the air temperature sensor 19 is higher than the first temperature At the above time, the defrosting operation is terminated.

Next, the operation of the above configuration will be described with reference to FIGS. FIG. 1 shows a flowchart of the control of the defrosting operation. When the defrosting operation is started on condition that the accumulated operation time of the compressor 22 reaches a predetermined time, first, in step S1, the compressor 22 is turned off and the defrost heater 17 is energized. As a result, the cooler 11 is heated and the attached frost melts.
Then, the temperature detected by the air temperature sensor 19 increases accordingly. In step S2, it is determined whether the temperature detected by the air temperature sensor 19 has reached the first temperature of 13 ° C., and if it has reached (YES), the flow proceeds to step S3.

In step S3, it is determined whether or not the detected temperature of the room temperature sensor 23 is equal to or higher than a predetermined temperature of 12 ° C. If it is equal to or higher than 12 ° C. (YES), the compressor 22 is energized as it is in step S4. At the same time, the defrost heater 17 is turned off to end the defrost operation. On the other hand, if the detected temperature of the room temperature sensor 23 is lower than 12 ° C. in step S3 (NO), the process proceeds to step S5. In step S5, it is determined whether or not the temperature detected by the air temperature sensor 19 reaches the second temperature of 15 ° C.
S) In step S4, the compressor 22 is energized, and the defrost heater 17 is turned off to terminate the defrost operation.

Here, even when the defrosting operation is started under the same condition (the integrated operation time of the compressor 22), the amount of frost on the cooler 11 may fluctuate due to moisture in the air. Among them, the temperature detected by the air temperature sensor 19 that detects the air temperature of a portion where the amount of frost is relatively large indicates a temperature followability according to melting of frost when the amount of frost of the cooler 11 is large. On the other hand, when the amount of frost formed on the cooler 11 is small, the frost is easily affected by the heat from the defrost heater 17,
Frost may rise before it has fully melted. However, the amount of frost formed by the cooler 11 is affected by the level of humidity. In other words, the amount of frost increases due to high humidity in summer such as the rainy season, and the amount of frost increases in winter when the humidity is low. Is also reduced. Therefore, the room temperature sensor 23
The season, that is, the amount of frost formation can be estimated based on the room temperature detected by the method.

According to the research of the present inventor, the air temperature sensor 1 when the frost adhering to the cooler 11 is completely removed is provided.
The relationship between the detected temperature of No. 9, ie, the air temperature at the end of the defrost (defrost end temperature) and the room temperature (the temperature detected by the room temperature sensor 23) is as shown in FIG. As shown in the figure, when the room temperature is 5 ° C., the defrost end temperature is approximately 15 ° C., which decreases as the room temperature rises, and when the room temperature exceeds 12 ° C., the defrost end temperature becomes approximately 13 ° C. regardless of the room temperature. I knew that.

Therefore, according to the present embodiment, the amount of frost differs depending on the room temperature, and when the amount of frost differs, the defrosting end temperature differs, so that when the room temperature is higher than 12 ° C. and lower than 12 ° C. Because the defrost end temperature is made different between
It is possible to execute the defrosting operation relatively according to the amount of frost formed in the cooler 11, and to terminate the defrosting operation at an appropriate time, thereby preventing the defrosting operation time from being unnecessarily long. Moreover, in this case, by using the room temperature sensor 22 conventionally used for operation control of the refrigerator, unlike the conventional one requiring two temperature sensors 2 and 3, the cooler 11 has one unit. The end time of the defrosting operation can be determined only by providing the temperature sensors 19,
The cost can be reduced.

FIGS. 7 to 10 show a second embodiment (corresponding to claim 2) of the present invention. The second embodiment differs from the first embodiment in that an evaporator temperature sensor 31 is provided in the cooler 11 in place of the air temperature sensor 19 and that the control circuit 21 has a software configuration. . Therefore, the other parts are the same as those in the first embodiment, so that the detailed description will be omitted and the reference numerals will be used in common, and only the differences will be described below.

As shown in FIG. 7 and FIG.
On the left side of the drawing, a mounting concave portion 32 is formed by curving the upper portion of the left side inward. For example, an EVA temperature sensor 31 composed of a thermistor is mounted by a mounting member 33 in a state fitted in the mounting concave portion 32. Have been. At this time, the mounting member 33 is made of a metal having good heat conductivity, and thus the temperature sensor 31 is in thermal contact with the cooler 11 over the entire outer peripheral surface thereof.
6, the temperature (evaporating temperature) of the portion where the amount of cold air is small and the frost hardly adheres is directly detected.

When the detected temperature of the room temperature sensor 23 is equal to or lower than the predetermined temperature (12 ° C.), the control circuit 21 as the control means determines whether the temperature detected by the evaluation temperature sensor 31 is equal to or higher than the first temperature (13 ° C. in this case). To end the defrosting operation,
When the temperature detected by the room temperature sensor 23 exceeds a predetermined temperature, the defrosting operation is terminated when the temperature detected by the evaluation temperature sensor 31 is equal to or higher than a second temperature (17 ° C. in this case).

That is, as shown in FIG. 9, when the defrosting operation control is started, first, in step S6, the compressor 2 is operated.
2 and the defrost heater 17 is energized. Thereby, the defrost of the cooler 11 is performed, and the detection temperature of the evaluation temperature sensor 31 increases. In step S7, it is determined whether or not the temperature detected by the evaluation temperature sensor 22 has reached 13 ° C., and if it has reached (YES), the process proceeds to step S8. In step S8, it is determined whether or not the detected temperature of the room temperature sensor 23 is equal to or lower than 12 ° C.
S) In step S9, the compressor 22 is energized, and the defrost heater 17 is turned off to terminate the defrost operation.
On the other hand, in step S8, the detected temperature of the room temperature sensor 23 becomes 12
If the temperature exceeds ℃ (NO), the process proceeds to step S10. Then, in step S10, it is determined whether or not the temperature detected by the evaporator temperature sensor 31 reaches 17 ° C., and if it has reached (YES), the compressor 22 is energized in step S9 and the defrost heater 17 is turned off to remove electricity. The frost operation ends.

Here, the detected temperature of the air temperature sensor 31 is opposite to the detected temperature of the air temperature sensor 19 of the first embodiment. Despite the corresponding temperature followability, when the amount of frost is large, the frost tends to rise before it is not completely melted. In this case, as in the first embodiment, the amount of frost can be estimated based on the room temperature detected by the room temperature sensor 23.

According to the study of the present inventor, the evaporating temperature sensor 3 when the frost adhering to the cooler 11 is completely removed.
The relationship between the detected temperature of 1, ie, the temperature of the cooler 11 at the end of the defrost (defrost end temperature) and the room temperature is as shown in FIG. As shown in the figure, when the room temperature is 5 ° C., the defrost end temperature is approximately 13 ° C., which is substantially constant until the room temperature reaches 12 ° C., gradually increases when the room temperature exceeds 12 ° C.
It was found that the defrosting end temperature at a temperature of ° C. was approximately 17 ° C.

Therefore, in the case of this embodiment, as in the first embodiment, the amount of frost differs depending on the room temperature. And when the temperature exceeds 12 ° C., the defrosting end temperature is made different, so that the defrosting operation can be performed relatively in accordance with the amount of frost formed on the cooler 11, and the defrosting operation can be performed at an appropriate time. The operation can be terminated, and it is possible to prevent the defrosting operation time from being unnecessarily long. In addition, in this case, too, by using the room temperature sensor conventionally used for operation control of the refrigerator, the cooler 11 is provided with one temperature sensor 3.
Only by providing 1, the end time of the defrosting operation can be determined, and the cost can be reduced.

[0031]

As described above, according to the present invention, the cooler is provided with only one temperature sensor, and the end time of the defrosting operation is determined based on the temperature detected by this temperature sensor and the temperature detected by the room temperature sensor. At this time, the defrost end temperature is made different between when the room temperature is high and when the room temperature is low, so that the defrost operation can be relatively shortened. Further, it is not necessary to provide two temperature sensors in the cooler as in the related art, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a control procedure in a defrosting operation according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of a cooler portion.

FIG. 3 is an enlarged exploded perspective view of an air temperature sensor and a holder.

FIG. 4 is a block diagram of an electrical configuration related to a defrosting operation.

FIG. 5 is a diagram showing a relationship between a defrost end temperature and a room temperature.

FIG. 6 is a diagram showing a flow of cool air in a cooler portion by a blowing action of a fan

FIG. 7 is a view corresponding to FIG. 2, showing a second embodiment of the present invention;

FIG. 8 is a diagram corresponding to FIG. 3;

FIG. 9 is a diagram corresponding to FIG. 1;

FIG. 10 is a diagram corresponding to FIG. 5;

FIG. 11 is a diagram corresponding to FIG. 2 showing a conventional example.

FIG. 12 is a diagram corresponding to FIG. 1;

FIG. 13 is a diagram corresponding to FIG. 5;

[Explanation of symbols]

11 is a cooler, 16 is a fan, 17 is a defrost heater (heater), 19 is an air temperature sensor, 21 is a control circuit (control means), 23 is a room temperature sensor (room temperature detection means), and 31 is an evaporator temperature sensor. .

Claims (2)

(57) [Claims] 1. A defrosting device comprising a cooler and a fan for blowing air through the cooler, and capable of performing a defrosting operation in which the cooler is heated by a heater to perform defrosting while the cooling operation is stopped. An air temperature sensor disposed in a portion of the cooler where the amount of air flow by the fan is large and where frost tends to form, an air temperature sensor, a room temperature detecting means for detecting a temperature around a refrigerator, and the defrosting operation. Control means for controlling the end of the defrosting operation, wherein the control means performs a defrosting operation when the temperature detected by the air temperature sensor is equal to or higher than a first temperature when the room temperature detected by the room temperature detecting means is equal to or higher than a predetermined temperature. When the room temperature detected by the room temperature detecting means is lower than the predetermined temperature, the defrosting operation is ended when the temperature detected by the air temperature sensor is equal to or higher than a second temperature higher than the first temperature. Refrigerator, characterized in that it is configured to. 2. A cooling device comprising: a cooler; and a fan for blowing air through the cooler, and capable of executing a defrosting operation in which the cooling device is heated by a heater to perform defrosting while the cooling operation is stopped. In the cooler, an air temperature sensor that is disposed in a portion of the cooler where the amount of air flow by the fan is less likely to be frosted and detects a temperature of the cooler, a room temperature detecting unit that detects a temperature around a refrigerator, Control means for controlling the end of the defrosting operation, wherein the control means removes when the temperature detected by the evaporating temperature sensor is equal to or higher than a first temperature when the room temperature detected by the room temperature detecting means is equal to or lower than a predetermined temperature. The frost operation is terminated, and when the room temperature detected by the room temperature detection means exceeds a predetermined temperature, the defrost operation is performed when the temperature detected by the evaluation temperature sensor is equal to or higher than a second temperature higher than the first temperature. Refrigerator, characterized in that it is configured to terminate.