JPH0423192B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a forced cooling operation control device for arbitrarily and forcibly operating an electric compressor of a refrigerator.

Conventional Structure and Problems Conventionally, the interior of the refrigerator is forcibly cooled down to a low temperature by continuously operating an electric compressor and a blower using a forced cooling switch. After the forced cooling operation ends, the cooling operation is not started unless the temperature reaches the set temperature.

This time generally takes about 2 hours, and when the electric compressor and blower start operating due to a rise in the temperature inside the refrigerator, the temperature of the cooler or the temperature of the refrigerator compartment increases due to opening and closing of the door. Then, warm air is circulated inside the refrigerator by a blower, and frozen foods, etc.
This method had the drawback that the temperature of stored food temporarily rose, which had an adverse effect on the food.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a forced cooling operation control device for a refrigerator that eliminates the circulation of warm air due to temperature rises in the cooler of the cooling system or the refrigerator, and is controlled so as not to adversely affect food products.

Structure of the Invention In order to achieve this object, the present invention inputs an operation signal to a forced cooling switch to start operation in the next cooling operation after the forced cooling operation ends, and stops the electric compressor after a predetermined time. The first output signal
inputting a timer and a stop signal for the electric compressor from the switch or the first timer to start operation;
a second timer that outputs a signal every predetermined time;
A temperature change circuit is provided which inputs the signal from the timer, lowers the set temperature of the temperature detection circuit, and then gradually changes the set temperature to the initial set temperature in synchronization with the output signal of the second timer. Cooling operation is performed by lowering and changing the set temperature in stages by a temperature change circuit until the timer stops, and after the timer stops, cooling operation is performed to return the operating point to the original value.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

Reference numeral 1 denotes a temperature detection circuit for detecting the temperature of the freezer compartment inside the refrigerator, and is composed of a comparator 2, resistors R ₁ , R ₂ , R ₃ , and a thermistor TH1.

These resistors R ₁ and R ₂ are connected to the V _CC power supply, and the resistor R ₁
and thermistor TH1 are connected in series, and this connection point is connected to one input terminal of comparator 2.

Further, the resistor R ₂ and the resistor R ₃ are connected in series,
This connection point is connected to one input terminal of the comparator 2. One end of the thermistor TH1 and the resistor _R3 are connected to GND.

Reference numeral 3 denotes a temperature changing circuit, which is composed of transistors ₄ , ₅ , and 6 and resistors R 4 , R 5 , R ₆ , R ₇ , R ₈ , and R ₉ .

The resistor R ₄ is connected to the collector of transistor 4;
Resistor R ₅ is connected to the collector of transistor 5, and resistor R ₆
are connected to the collector of transistor 6, and the other ends of resistors R ₄ , R ₅ , and R ₆ are connected to each other. Also, connect the connection point of resistors R ₄ , R ₅ , and R ₆ to resistor R ₂ .
It is connected to the connection point of R ₃ and to the 1 input terminal of comparator 2.

The base of the transistor 4 and the resistor R ₇ , the base of the transistor 5 and the resistor R ₈ , and the transistor 6
The bases of the transistors are connected to the resistor _R9 , respectively, and the emitters of the transistors 4, 5, and 6 are connected to GND.

Reference numeral 7 denotes a control circuit consisting of a flip-flop circuit, to which data input and output are connected. Reference numeral 8 denotes a flip-flop circuit, the data input and output of which are connected, and the clock input of the control circuit 7 and the output of the flip-flop circuit 8.

9 is an OR circuit. And comparator 2
is connected to one input of the OR circuit 9, and the other input of the OR circuit 9 is connected to the Q output of the flip-flop circuit 8. The output of OR circuit 9 is resistor R ₁₀
is connected to the base of transistor 10 via.

A relay 1 is connected to the collector of this transistor 10.
1 is connected, and the emitter is connected to GND.

This relay 11 has a normally open contact 12.

13 is an electric compressor of a cooling system that cools the inside of the refrigerator; 14 is a blower that forcibly circulates cold air between the freezer compartment and the refrigerator compartment; 15 and 16 are power terminals; and 17 is a door switch. The power terminal 15 is connected to the electric compressor 13 and the door switch 17. Further, the normally open contact 12 of the relay 11 is connected to the power supply terminal 16, and the other end is connected to the electric compressor 13 and the blower 1.
4, and the blower 14 and door switch 17 are connected.

Reference numeral 18 denotes a switch for forced cooling, which is connected to the _Vcc power supply, and the other end is connected to the resistor R ₁₁ and the clock input of the flip-flop circuit 8. The other end of resistor _R11 is connected to GND. The Q output of the flip-flop circuit 8 is connected to each input of an AND circuit 19 and an OR circuit 9. Flip-flop circuit 8
The reset terminal of is connected to the output of the one shot circuit 20. The output of the AND circuit 19 is connected to the input of the one shot circuit 20. The one-shot circuit 20 is configured to generate a positive pulse signal when the input signal changes from "1" to "0".

Reference numeral 21 denotes an oscillation circuit, which is composed of gate circuits 22, 23, a resistor _R12 , and a capacitor _C1 .

One input of the gate circuit 22 is connected to the output of the flip-flop circuit 8, and the other input of the gate circuit 22 is connected to a resistor _R12 and a capacitor _C1 .
Then, the output of the gate circuit 22 and the gate circuit 23
The input of is connected and also connected to one end of resistor _R12 .

The output of this gate circuit 23 is connected to a capacitor _C1 .

The oscillation circuit 21 is configured to oscillate by performing charge/discharge cycles with a time constant determined by a resistor R ₁₂ and a capacitor C ₁ .
While giving "0" to the input, that is, the input connected to the output of the flip-flop circuit 8,
It continues oscillating and stops when it is "1".

24 is the first timer and flip-flop circuit FF
It consists of 7 pieces, FF1, FF2...FF7, and the Q output of each is connected to the clock input. Also, each output and data input are connected. Furthermore, each reset terminal is a one-shot circuit 20.
is connected to the output of The input terminal of this first timer 24 is connected to the output of the gate circuit 23.

Reference numeral 25 denotes an oscillation circuit, which is composed of gate circuits 26, 27, a resistor _R13 , and a capacitor _C2 .

One input of the gate circuit 26 is the control circuit 7.
The other inputs of the gate circuit 26 are connected to the resistor _R13 and the capacitor _C2 . The output of the gate circuit 26 and the input of the gate circuit 27 are connected, and also connected to one end of the resistor _R13 . The output of this gate circuit 27 is connected to a capacitor _C2 .

The oscillation circuit 25 is configured to perform charge/discharge cycles and oscillate with a time constant determined by a resistor R ₁₃ and a capacitor C ₂ , and one input of the gate circuit 26 , that is, the input connected to the output of the control circuit 7 is set to “0”. ” continues to oscillate, and stops when it is “1”. 28 is a second timer consisting of four digit flip-flop circuits FF8, FF9, FF10, and FF11, each of which has a Q output connected to a clock input. Also, each output and data input are connected.

Further, the reset terminal is connected to the final stage Q of the second timer 28. The final stage Q output of the second timer 28 is also connected to the reset terminal of the control circuit 7. Further, the second timer 28 has Q _A , Q _B , Q _C as intermediate outputs, and the intermediate output Q _A has resistors R ₉ , Q _B
is connected to resistor R ₈ , and Q _C is connected to resistor R ₇ .

Next, the operation of the circuit configured as described above will be explained.

Thermistor placed in the freezer compartment (not shown)
TH1 is in a state where the resistance value is small when the temperature inside the refrigerator is higher than the set value. At this time, the output of the control circuit 7 is in the "1" state, and the oscillation circuit 25 does not oscillate and is in a stopped state. Therefore, the second timer 28
doesn't work. Intermediate output of the second timer 28
Q _A , Q _B , Q _C are in the "1" state, transistors 4, 5, and 6 are in the on state via resistors R ₇ , R ₈ and R ₉ , respectively, and resistors ₃ , R ₄ , R _Five ,
and R ₆ are connected in parallel and the combined resistance is R _A
Then, R _A = R ₃ R ₄ R ₅ R ₆ / R ₃ R ₄ (R ₅ R ₆ ) + R ₅ R ₆ (R ₃ + R ₄ ). (R ₄ > R ₅ > R ₆ ).

If the internal temperature is high, resistor R ₁ and thermistor
The output of comparator 2 is "1" because the divided potential of resistor R ₂ and combined resistor _RA is higher due to the divided potential of TH1.

Since one input of the OR circuit 9 becomes "1", the output also becomes "1", and the transistor 10 is turned on via the resistor R ₁₀ to excite the relay 11. When this relay 11 is energized, its normally open contact 12 is closed, and the power terminals 15 and 16 are connected to the electric compressor 13 and blower 14, and the electric compressor 13 and blower 14 are started to cool the inside of the refrigerator. Do this. Also,
When the refrigerator door is closed, the door switch 17 is opened, and the blower 14 is connected to the power terminals 15 and 16.
When the door is closed, the door switch 17 is closed and the blower 14 is again connected to the power terminals 15 and 16 and starts operating. Further, while the relay 11 is energized, the blower 14 operates or stops depending on the state of the door switch 17.

The temperature inside the refrigerator decreases due to the operation of the electric compressor 13 and the blower 14. When the temperature of the freezer compartment decreases, the resistance of thermistor TH1 gradually increases.
When the temperature becomes lower than the set value, thermistor TH1
As the resistance of the resistor _R1 and thermistor TH1 increases, the divided potential of the resistor R1 and the thermistor TH1 becomes higher than the divided potential of the resistor _R2 and the combined resistor _RA , and the output of the comparator 2 becomes "0". When the output of comparator 2 becomes “0”,
The output of the OR circuit 9 changes from "1" to "0",
Transistor 10 is turned off and relay 11
stops working. When the relay 11 stops operating, the normally open contact 12 opens, and the electric compressor 13 and blower 14 are disconnected from the power terminals 15 and 16, and stop operating. As the cooling operation is stopped, the temperature inside the refrigerator gradually increases, and the resistance of the thermistor TH1 decreases.When the temperature inside the refrigerator increases and exceeds the set value, the resistance value of the thermistor TH1 decreases, and as described above, the output of the comparator 2 decreases. The signal becomes "1", and the electric compressor 13 and blower 14 start operating again and enter cooling operation. The refrigerator is maintained at the set temperature by repeating cooling operation and stopping as described above.

Next, forced cooling operation will be explained.

When the forced cooling switch 18 is in the OFF state, the clock input of the flip-flop circuit 8 is in the "0" state, and the Q output is also in the "0" state. Further, the output is "1", so the oscillation circuit 21 is in a stopped state, and the first timer 24 does not operate.

When the forced cooling switch 18 is activated and turned on, the clock input of the flip-flop circuit 8 changes from "0" to "1", and a flip-flop operation is performed, the Q output changes from "0" to "1", and the output changes to "1". ” changes to “0”. The forced cooling switch 18 is a switch that turns on only when activated and turns off immediately.

The input of the oscillation circuit 21 is the flip-flop circuit 8.
When the output becomes "0", oscillation starts, and the first timer 24 performs a counting operation. Then, when the Q output of the flip-flop circuit 8 becomes "1",
One input of the OR circuit 9 becomes “1”, and the thermistor
Regardless of the output state of the comparator 2 due to the state of TH1, the output of the OR circuit 9 becomes "1", and as mentioned above, the transistor 10 is turned on,
The relay 11 is energized, the normally open contact 12 is closed, and the electric compressor 13 and blower 14 are connected to the power terminals 15 and 16.
It is connected to the engine, starts up, and enters forced cooling operation. Due to forced cooling operation, the temperature inside the refrigerator decreases, and the thermistor TH
Even if it detects that 1 is lower than the set value, the OR circuit 9
Since the Q output of the flip-flop circuit 8 is "1", the output is "1" and the cooling operation is continued.

Since the output of the flip-flop circuit 8 is "0", the oscillation circuit 21 continues to oscillate, and the first timer 24 continues to count input pulses.

As the count operation progresses, the final stage Q output, that is, the output of the flip-flop circuit FF7 becomes "0".

The output of flip-flop circuit FF7 is “0”
When this happens, one input of the AND circuit 19 becomes "0" and the output changes from "1" to "0". AND circuit 19
When the output falls from "1" to "0", the one-shot circuit 20 outputs one positive pulse in synchronization with the fall of this pulse. The first timer 24 is activated by the pulse signal of the one-shot circuit 20.
This signal is sent to the reset terminal of the flip-flop circuit 8 and the reset terminal of the flip-flop circuit 8, and each is reset. The counted contents of the first timer 24 are all "0". The flip-flop circuit 8 is also reset, and the output changes from "0" to "1" and the oscillation circuit 21 stops oscillating. In addition, when the output of the flip-flop circuit 8 changes from "0" to "1", the control circuit 7 also changes the clock input from "0" to "1", causing a flip-flop operation, and the Q output changes from "0" to "1". The output is
Changes from “1” to “0”.

Then, when the output of the control circuit 7 becomes "0", the oscillation circuit 25 starts oscillating, a pulse is input to the clock input of the second timer 28, and the second timer 28 starts to oscillate.
8 performs a counting operation. The intermediate output Q _A of the second timer 28 becomes “1” at the same time as the oscillation circuit 25 oscillates.
becomes “0”.

When the intermediate output Q _A of the second timer 28 becomes "0", the transistor 6 changes from the on state to the off state via the resistor R ₉ , current no longer flows through the resistor R ₆ , and the first input of the comparator 2 is connected to the resistor R ₂ and resistance
The combined resistance R _B of R ₃ , R ₄ , and R ₅ (R _B = R ₃ R ₄ R ₅ / R ₃ (R ₄ + R ₅ ) + R ₄ R ₅ (R _A < R _B )) A piezoelectric potential will be input.

Therefore, the partial voltage potential of resistor R1 and thermistor TH1 becomes higher than that during normal cooling operation, and the resistance value of thermistor _TH1 is high, that is, the set value of the refrigerator temperature is lower than during normal cooling operation. becomes lower than the divided potential of resistor R ₂ and combined resistor R _B ,
The output of comparator 2 will be "1". When the forced cooling operation ends, the output of the comparator 2 is "0" because the interior of the refrigerator is sufficiently cooled even if the set temperature becomes low as described above, and both the two inputs of the OR circuit 9 become "0". The output becomes "0", the transistor 10 is turned off, and the operations of the electric compressor 13 and the blower 14 are stopped. When the forced cooling operation ends and the internal temperature gradually rises to the lower set temperature, the resistance R ₁
The divided voltage potential of resistor R ₂ and combined resistor R _B becomes higher than the 1 divided voltage potential of thermistor TH1, the output of comparator 2 becomes "1", and the 1 input of OR circuit 9 becomes "1". Transistor 10 is on and relay 11 is energized. Therefore, the electric compressor 13 and the blower 14 are started and enter cooling operation.

When the temperature inside the refrigerator decreases due to cooling operation, the resistance value of thermistor TH1 increases, and the resistance value of the thermistor _R1 and the thermistor increase.
The divided potential of TH1 becomes higher than the divided potential of resistor R ₂ and combined resistor R _B , and the output of comparator 2 becomes "0".

When the output of the comparator 2 becomes "0", the transistor 10 is turned off, the relay 11 stops operating, the normally open contact 12 is opened, and the electric compressor 1
3. The blower 14 stops operating. As the cooling operation is stopped, the temperature inside the refrigerator gradually increases, causing the thermistor to
The resistance of TH1 becomes smaller, and the output of comparator 2 becomes "1" as described above, and electric compressor 13 and blower 14 start operating again and enter cooling operation. Then, the second timer 28 is activated by the operation of the oscillation circuit 25, and during time _t1 (the state of t1 in FIG. ₂ ), the input of the comparator 2 is at the divided potential of the combined resistor R _B and the resistor _R2 . Comparator 2 operates by comparing the divided potential of thermistor TH1 and resistor _R1 , and the output becomes “0”.
or "1", and the cooling operation and stop are repeated as described above.

When time _t1 elapses due to the operation of the second timer 28, the intermediate output Q _A of the timer 28 changes from "0" to "1", and the intermediate output Q _B changes from "1" to "0".
(Status at the end of _t1 in Figure 2).

Then, the intermediate output Q _A of the second timer 28 is “1”
When Q _B becomes “0”, transistor 6
turns from the off state to the on state, and the transistor 5 changes from the on state to the off state (the state at the end of t1 in FIG. ₂ ). Therefore, one input of comparator ₂ is the combined resistance R _C (R _C = R _{3 R 4} R ₆ /R ₃ ( _{R 4 + R 6 )} + R ₄ R ₆ However, (R _A <
A divided potential of R _C <R _B )) will be input.
Therefore, the intermediate output Q _A of the second timer 28 is “0”
During t ₁ hour (state of t ₁ in Figure 2), the temperature inside the refrigerator is slightly higher and the output of comparator 2 is "1", but the temperature inside the refrigerator is higher than during normal cooling operation. Until the temperature set value is low, the divided potential of resistor R ₁ and thermistor TH1 becomes resistor R ₂ and the combined resistance.
It becomes lower than the divided potential of R _C , and the output of comparator 2 becomes "1".

When the output of comparator 2 becomes “1”,
As mentioned above, the electric compressor 13 and the blower 14 start and enter cooling operation, and when the temperature inside the refrigerator decreases and the resistance value of the thermistor TH1 increases, the comparator 2
The output becomes "0", and the electric compressor 13 and blower 14 stop.

Also, the intermediate output Q _B of the second timer 28 is “0”
In other words, during the time t ₂ (state of _{t 2} in Figure ₂ ), the comparator ₂ is The output becomes "1" or "0", and depending on the output state of the comparator 2, the cooling operation and stop are repeated as described above.

Next, by the operation of the oscillation circuit 25, the second timer 28
As the counting operation progresses and time (t ₁ + t ₂ ) elapses, the intermediate output Q _B of the second timer 28 changes from “0” to “1”, and Q _C changes from “1” to “0” (the second figure
t ₂ end status).

Then, when the intermediate output Q _B of the timer 28 becomes "1" and Q _C becomes "0", the transistor 5 changes from the off state to the on state, and the transistor 4 changes from the on state to the off state. Therefore, one input of comparator 2 is the combined resistance of resistor R ₂ and resistors R ₃ , R ₅ , and R ₆ .
R _D (R _D = R ₃ R ₅ R ₆ / R ₃ (R ₅ + R ₆ ) + R ₅ , R ₆ However, (R _A <
A divided potential of R _D <R _C <R _B )) will be input. Therefore, while the intermediate output Q _B of the second timer 28 is "0", that is, during time t ₂ (state of t 2 in Fig. ₂ ).
The comparator 2 operates so that the output of the comparator 2 becomes "1" when the internal temperature is a little higher. Then, until the set value of the internal temperature is lower than during normal cooling operation, the partial voltage potential of resistor R ₁ and thermistor TH1 becomes lower than the partial voltage potential of resistor R ₂ and combined resistor R _D , and the output of comparator 2 becomes It becomes “1”. When the output of the comparator 2 becomes "1", the electric compressor 13 enters cooling operation. When the temperature inside the refrigerator drops due to cooling operation,
The output of the comparator 2 becomes "0" and the cooling operation is stopped. While the intermediate output Q _C of the second timer 28 is “0”, that is, for t ₃ time (state of t ₃ in Fig. 2)
The voltage between resistor _R1 and thermistor TH1 is
The comparator 2 operates depending on the input state of the divided potential of the resistor R ₂ and the combined resistor R _D , and the electric compressor 1
3 repeats cooling operation and stopping. When the counting operation of the second timer 28 progresses and the time (t ₁ + t ₂ + t ₃ ) (state at the end of t ₃ in FIG. 2) has elapsed, the final stage Q output of the second timer 28 becomes "1", and the control circuit 7 The reset terminals of the second timer 28 and the second timer 28 each receive a reset signal. and control circuit 7
The output becomes "1" and one input of the gate circuit 26 becomes "1", causing the oscillation circuit 25 to stop oscillating.
When the second timer 28 is reset, the intermediate output Q _A ,
Q _B and Q _C become "1", the final stage Q output becomes "0", and the second timer 28 does not perform a counting operation.
Furthermore, when the intermediate outputs Q _A , Q _B , Q _C of the second timer 28 all become "1", the transistors 4 , 5 , 6 are all turned on, and the resistors R ₃ , R ₄ , R ₅ ,
R ₆ is all in parallel and combined resistance with resistance R ₂
The divided potential of R _A becomes one input of comparator 2,
The temperature returns to the normal set temperature, and the cooling operation and stop are repeated as described above, and the inside of the refrigerator is maintained at the set temperature.

Therefore, as described above, in the forced cooling operation, the set temperature is gradually increased from a low value at regular intervals, and the temperature is returned to the normal set temperature, and the cooling operation is performed.

When the forced cooling switch 18 is operated again and turned on, the forced cooling operation begins as described above. The forced cooling operation is continued for a time-safe period set by the first timer 24, but if it is desired to stop within this time-safe period, the forced cooling switch 18 is activated again.

Since the output of the data input of the flip-flop circuit 8 is "0", the clock input is "0".
It operates when the signal changes from “1” to “1”, and the Q output changes from “1” to “0”. The first timer 24 is reset by the one-shot circuit 20, and the forced cooling operation is terminated by the Q output of the flip-flop circuit 8. After this forced cooling operation, as described above, the operating point of the comparator 2 is changed stepwise by the second timer 28, cooling operation and stop are repeated, and then normal cooling operation is resumed to maintain the inside of the refrigerator at the set temperature.

Effects of the Invention As is clear from the above explanation, the present invention operates a timer after forced operation of the electric compressor and blower, and while this timer is operating, the operating point of the temperature detection circuit is changed from a low temperature to the desired set temperature. The operating point of the temperature detection circuit is changed in stages, and the operating point of the temperature detection circuit is returned to its original state after the timer stops, so cooling operation can be performed early after the forced operation ends, and the temperature of the refrigerator compartment due to the temperature of the cooler or opening/closing of the door may be high. Preserved foods can be stored well by preventing high-temperature air from circulating inside the refrigerator and by using a blower to circulate sufficiently cool air.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing a forced cooling operation control device for a refrigerator according to an embodiment of the present invention, and FIG.
FIG. 3 is a time chart of a second timer that operates after the forced cooling operation shown in the figure. 1...Temperature detection circuit, 3...Temperature change circuit, 7
...Control circuit, 13...Electric compressor, 14...Blower, 18...Switch, 24...First timer,
28...Second timer.

Claims (1)

[Claims] 1. An electric compressor of the cooling system that cools the inside of the refrigerator, a blower that forcibly circulates cold air between the freezer compartment and the refrigerator compartment, and detects the internal temperature of the freezer compartment and compares it with the set temperature. a temperature detection circuit that outputs an operation or stop signal for the electric compressor; a forced cooling switch that has a normally open contact and outputs an operation or stop signal for the electric compressor when the contact is closed; and an operation of the switch. a first timer that inputs a signal to start operation, and outputs a stop signal for the electric compressor after a predetermined time; and a first timer that inputs a stop signal for the electric compressor from the switch or the first timer and starts operation. After inputting a second timer that outputs a signal at predetermined time intervals and a signal from the second timer, and lowering the set temperature of the temperature detection circuit in synchronization with the start of operation of the second timer, A forced cooling operation control device for a refrigerator, comprising a temperature change circuit that changes the temperature to a desired set temperature in stages in synchronization with the output signal of the second timer.