JPH0221743Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention relates to a refrigerator equipped with a freezing compartment and a refrigerating compartment.

(Prior Art) For example, a direct cooling type refrigerator equipped with a freezer compartment and a refrigerator compartment has conventionally been configured to perform on/off control of a compressor according to the temperature in the freezer compartment, and when the compressor is driven ( In other words, when the temperature in the refrigerator compartment rises to a predetermined temperature or higher (in a state where the temperature in the freezer compartment is higher than a set value), refrigerant is supplied to both the cooler for the freezer compartment and the cooler for the refrigerator compartment.

(Problem to be solved by the invention) In the refrigerator with the above-mentioned conventional configuration, the load amount increases due to factors such as frequent opening and closing of the doors for the freezer and refrigerator compartments, or the storage of new items. When the internal temperature of the freezer compartment and refrigerator compartment increases, refrigerant will be supplied to both the freezer compartment cooler and the refrigerator compartment cooler, but at this time, the load amount will be extremely high. If the temperature increases, the refrigerant evaporation temperature in the refrigerator compartment cooler becomes excessively high, which causes deterioration of the cooling effect of the freezer compartment cooler, leading to an increase in the temperature in the freezer compartment. However,
Since ice cream and other frozen foods for long-term storage that are easily affected by temperature increases are stored in the freezer compartment, it is necessary to reliably prevent the temperature in the freezer compartment from rising above the limit. It is hoped that Incidentally, when ice cream is stored at a temperature of -8°C or higher, it becomes soft and the fat content separates.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a refrigerator that can reliably prevent the temperature of the freezer compartment from rising above the limit and eliminate the possibility of adverse effects on stored items in the freezer compartment.

[Structure of the invention] (Means for solving the problem) In order to achieve the above object, the present invention provides a first state in which cold air is supplied to both the freezer compartment and the refrigerator compartment when the compressor for the refrigeration cycle is driven. a switching device capable of switching to a second state that supplies cold air only to the refrigerator compartment; a temperature control unit for the freezer compartment that drives the compressor when the temperature in the refrigerator compartment is equal to or higher than a set temperature; A temperature control unit for a refrigerator compartment that switches the switching device to a first state and switches the switching device to a second state when the temperature in the refrigerator compartment is lower than a set temperature, when the switching device is in the first state. The apparatus is configured to include a temperature guarantee means for forcibly switching the switching device to the second state when the temperature in the freezer exceeds a predetermined guaranteed temperature.

(Function) When the switching device is in the first state, that is, in a state where cold air is supplied to both the freezer compartment and the refrigerator compartment, when the temperature in the freezer compartment reaches a predetermined guaranteed temperature or higher, the temperature guarantee means switches the switching device to the first state. The device is forced to switch to the second state, that is, the state in which cold air is supplied only to the freezer compartment. As a result, all of the cooling capacity is allocated to cooling the freezer compartment, thereby preventing the temperature in the freezer compartment from rising above the limit.

(Example) Hereinafter, an example in which the present invention is applied to a direct cooling type refrigerator will be described with reference to the drawings.

In FIG. 1, 1 is a refrigerator body having a freezer compartment 2 and a refrigerator compartment 3, 4 is a freezer compartment cooler disposed around the freezer compartment 2, and 5 is a cooler located at the upper part of the refrigerator compartment 3. 6 is a compressor,
7 is a door for the freezer compartment, and 8 is a door for the refrigerator compartment.

FIG. 2 shows a known refrigeration cycle to which the present invention is applied. In FIG. 2, 9 is a condenser, 10 is a main capillary tube, 11 is an auxiliary capillary tube, 12 is a solenoid valve as a switching device, and 13 is a bypass capillary tube, which are connected to the freezer compartment cooler. 4 and the refrigerator compartment cooler 5 as well as the discharge port 6a of the compressor 6.
and the suction port 6b as shown in the figure.
In such a refrigeration cycle, the solenoid valve 12 is configured to be in a closed state when the power is cut off and to be in an open state when the power is applied. It exhibits a "first state" in which refrigerant is supplied to both the cooler 5 and the freezer cooler 4, and a "first state" in which refrigerant is supplied only to the freezer cooler 4 via the bypass capillary tube 13 when in the open state. It is designed to switch to the second state.

Now, FIG. 3 shows only the portions of the electric circuit configuration of the two-temperature refrigerator that are related to the gist of the present invention. In FIG. 3, reference numeral 14 denotes a temperature control section for a refrigerating room whose set temperature TR can be changed by a variable resistor 15a, and has the following construction. That is, 16a is a thermistor (having a negative temperature resistance characteristic) arranged to detect the temperature of the refrigerator compartment cooler 5 and the temperature inside the refrigerator compartment 3.
So, one end of this is a constant voltage positive power supply terminal +V
cc, and the other end is connected to the ground terminal via a resistor 16b. Therefore, a voltage signal VDR indicating the temperature inside the refrigerator compartment 3 is output from the common connection point of the thermistor 16a and the resistor 16b, and the level of this voltage signal VDR is dependent on the temperature inside the refrigerator compartment 3. It changes directly proportionally. Further, the variable resistor 15a has one end connected to the positive power terminal +Vc.c.
The other end is connected to a ground terminal via a resistor 15b. As a result, variable resistor 15a and resistor 1
A reference voltage signal VSR for the refrigerator compartment corresponding to the set temperature TR is output from the common connection point 5b, and this voltage signal VSR is applied to the variable resistor 15.
The level can be adjusted by a. 17a is a comparator circuit consisting of an operational amplifier, which receives the voltage signal VDR at its non-inverting input terminal (+), and
The reference voltage signal for the refrigerator compartment is connected to the inverting input terminal (-).
Connected to receive VSR. As a result,
The comparator circuit 17a outputs a high level signal when the temperature detected by the thermistor 16a (that is, the voltage signal VDR) rises and exceeds the set temperature TR (that is, the voltage signal VSR), and the detected temperature exceeds the set temperature. Outputs a low level signal when the temperature drops below TR. At this time, a well-known hysteresis resistor 17b is connected to the comparison circuit 17a.
Therefore, in reality, a predetermined differential is applied to the set temperature TR at the time of output reversal as described above.

The output of the comparison circuit 17a is supplied to a drive circuit 20 via an inverter 18 and an OR circuit 19, and this drive circuit 20 closes the electromagnetic valve 12 only when receiving a high level signal.
Apply electricity to open it.

On the other hand, for 21, the set temperature TF is the variable resistance 22
This is a temperature control unit for a freezer compartment that can be changed by a, and has the following configuration. That is, 23a is a thermistor arranged to detect the temperature of the freezer compartment cooler 4 and the temperature inside the freezer compartment 2. One end of this thermistor is connected to the positive power terminal +Vc.c., and the other end is connected to the positive power terminal +Vc.c. is connected to the ground terminal via the resistor 23b. Therefore, a voltage signal VDF indicating the temperature inside the freezer compartment 2 is output from the common connection point of the thermistor 23a and the resistor 23b.
The level of this voltage signal VDF changes in direct proportion to the temperature inside the freezer compartment 2. Further, the variable resistor 22a has one end connected to the positive power supply terminal +Vc.c.
The other end is connected to the ground terminal via the resistor 22b. This results in
A reference voltage signal VSF for the freezer compartment corresponding to the set temperature TF is output from the common connection point of the variable resistor 22a and the resistor 22b, and the level of this voltage signal VSF can be adjusted by the variable resistor 22a. There is. 24a is a comparator circuit consisting of an operational amplifier, the non-inverting input terminal (+) of which receives the voltage signal VDF, and the inverting input terminal (-)
is connected to receive the refrigerator compartment reference voltage signal VSF. As a result, in the comparator circuit 24a, the temperature detected by the thermistor 23a (that is, the voltage signal VDF rises) rises, and the set temperature rises.
Outputs a high level signal when TF (that is, voltage signal VSF) is exceeded, and the detected temperature is the set temperature.
Outputs a low level signal when the voltage falls below TF. At this time, a well-known hysteresis resistor 24b is connected to the comparator circuit 24a, so that a predetermined differential is actually applied to the set temperature TF when the output is inverted as described above.

The output of the comparator circuit 24a is supplied to a drive circuit 26 via an OR circuit 25, and this drive circuit 26 drives the compressor 6 by energizing it only when it receives a high level signal. let

Reference numeral 27 denotes a switching control circuit as a temperature guarantee means, which also serves as the thermistor 23a of the freezer compartment temperature control section 21 as an internal temperature detecting means of the freezing compartment 2. VDF) is the predetermined guaranteed temperature, e.g. -8℃ (higher than the set temperature TF)
When the detected temperature is -13°C, for example, the comparator circuit 28a outputs a high level signal.
When the value is below, the comparison circuit 28a outputs a low level signal. Then, the comparison circuit 28a
The outputs of are input to OR circuits 19 and 25. In addition, 28b is a well-known hysteresis resistor connected to the comparison circuit 28a, 29a, 29b
is a resistor for generating a reference voltage for comparison.

Next, the operation of this embodiment having the above configuration will be explained. Now, during normal operation, the refrigerator compartment cooler 5
That is, the temperature detected by the thermistor 16a is the upper limit of the set temperature TR (this is the hysteresis resistor 1
7b), the comparator circuit 17a
A high level signal is output from the comparator circuit 2, and when the temperature of the freezer compartment cooler 4, that is, the temperature detected by the thermistor 23 is higher than the upper limit of the set temperature TF (this is determined by the hysteresis resistor 24b), the comparison circuit 2
When a high level signal is also being output from 4a, a low level signal inverted by the inverter 18 is given to the drive circuit 20, so the electromagnetic valve 12 is shut off and switched to the "first state". A high level signal is applied to the drive circuit 26, and the compressor 6 is energized and driven. Therefore, the refrigerant discharged from the compressor 6 is supplied to both the refrigerator compartment cooler 5 and the freezer compartment cooler 4, and both the refrigerator compartment 3 and the freezer compartment 2 are cooled. Due to such cooling operation, the temperature inside the refrigerator compartment 3 decreases, and when the temperature detected by the thermistor 16a becomes equal to or lower than the lower limit value of the set temperature TR (determined by the hysteresis resistor 17b), the comparator circuit 1
A low level signal is output from 7a and the drive circuit 2
Since a high level signal is now given to 0, the solenoid valve 12 is energized and switched to the "second state". Therefore, the refrigerant discharged from the compressor 6 is supplied only to the freezer compartment cooler 4, and the cooling operation of the freezer compartment 2 is continued. When the temperature inside the freezer compartment 2 further decreases due to such cooling operation and the temperature detected by the thermistor 23a becomes below the lower limit value of the set temperature TF (determined by the hysteresis resistor 24b), a low level signal is sent from the comparator circuit 24a. is output, the compressor 6 is switched to the "third state" in which the power is cut off, and the operation of the refrigeration cycle is stopped. After this, the temperature detected by the thermistor 23a will be the set temperature.
When the upper limit value of TF is exceeded, driving of the compressor 6 is restarted, and the solenoid valve 12 is closed or opened depending on the temperature detected by the thermistor 16a, so that the same cooling operation as described above is repeated.

Now, when the cooling operation is normally performed as described above, the temperature detected by the thermistor 23a never exceeds the guaranteed temperature (-8°C), so a high level signal is output from the switching control circuit 27. Never. However, due to factors such as frequent opening and closing of the freezer compartment door 7 and refrigerator compartment door 8, or large amounts of new stored items being stored in the freezer compartment 2 and refrigerator compartment 3, the load amount becomes extremely large. If the refrigerant is being supplied to both the freezer cooler 4 and the refrigerator cooler 5 in an increased state, the refrigerant evaporation temperature in the refrigerator cooler 5 will become excessively high. This causes deterioration of the cooling effect of the freezer compartment cooler 4, and the temperature inside the freezer compartment 2 rises, causing the thermistor 2
3a (temperature of the freezer compartment cooler 4) may rise above the guaranteed temperature of -8°C. In this way, when the temperature detected by the thermistor 23a rises to -8°C or higher, a high level signal is output from the switching control circuit 27, and this is sent to the OR circuit 19,
The signal is applied to drive circuits 20 and 26 via 25.
Therefore, the electromagnetic valve 12 and the compressor 6 are energized regardless of the respective states of the refrigerator temperature control section 14 and the freezer temperature control section 21, and in this way, the air discharged from the compressor 6 is energized. The state is forcibly switched to the "second state" in which refrigerant is supplied only to the freezer compartment cooler 4, and cooling operation of only the freezer compartment 2 is performed. In this case, since the load on the freezer compartment 2 is normally set to account for about 1/3 of the load on the entire refrigerator, when the cooling operation of only the freezer compartment 2 is performed as described above, the load on the freezer compartment 2 is Even in a state where the load amount is extremely increased, the internal temperature of the freezer compartment 2 will decrease.
When the temperature detected by the thermistor 23a becomes -13°C or lower due to such a decrease in the internal temperature of the freezer compartment 2, a low level signal is output from the switching control circuit 27, and from then on, the temperature control for the refrigerator compartment is performed. The solenoid valve 12 and the compressor 6 are now controlled by the section 14 and the temperature control section 21 for the freezer compartment, so that normal cooling operation can be performed.

In the above embodiment, the present invention was applied to a direct cooling type refrigerator, but it goes without saying that the present invention may also be applied to a Fancool type refrigerator.

[Effects of the invention] As is clear from the above explanation, according to the present invention, it is possible to reliably prevent the temperature inside the freezer from rising beyond the limit, thereby preventing the storage of ice cream, etc. in the freezer. This has the advantage that there is no risk of adverse effects on the product.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a longitudinal sectional side view, Fig. 2 is a diagram showing a refrigeration cycle,
FIG. 3 is an electrical circuit diagram. In the figure, 2 is a freezer compartment, 3 is a refrigerator compartment, 4 is a cooler for the freezer compartment, 5 is a cooler for the refrigerator compartment, 6 is a compressor, 12 is a solenoid valve (switching device), and 14 is a temperature control unit for the refrigerator compartment. , 21 is a temperature control section for the freezer compartment, and 27 is a switching control circuit (temperature guarantee means).

Claims (1)

[Scope of utility model registration request] A switching device capable of switching between a first state in which cold air is supplied to both the freezer compartment and the refrigerator compartment and a second state in which cold air is supplied only to the freezer compartment when a refrigeration cycle compressor is driven, and a temperature in the freezer compartment is set. A temperature control unit for a freezer compartment that drives the compressor when the temperature is higher than a set temperature, and switches the switching device to a first state when the temperature in the refrigerator compartment is higher than a set temperature, and when the temperature in the refrigerator compartment is lower than the set temperature. a temperature control unit for a refrigerator compartment that switches a switching device to a second state when the switching device is in the first state and the switching device is forced to operate when the temperature in the freezing room becomes equal to or higher than a predetermined guaranteed temperature; 1. A refrigerator comprising temperature guarantee means for automatically switching to a second state.