JP7150185B2 - air conditioner - Google Patents

Description

TECHNICAL FIELD The present invention relates to an air conditioner having a thermal protector that protects a compressor.

Patent Literature 1 describes an air conditioner having a compressor protection device. The protection device of Patent Literature 1 is attached to the outer shell of the compressor and includes a bimetal and a plurality of receptacles. A plurality of conductive pins are provided in the compressor enclosure, and the plurality of receptacles of the protective device are directly fitted and connected to the plurality of conductive pins, respectively. One of the receptacles is connected to one contact of the bimetal, and a connector is connected to the other contact of the bimetal. AC power is supplied to the electric element of the compressor through a connector, a bimetal, and a current-carrying pin. When an overcurrent flows through the compressor or the outer shell of the compressor becomes abnormally hot, the bimetal is thermally deformed. Accordingly, the connection between the bimetal and the connector and the connection between the bimetal and the current-carrying pin are released. That is, the electric circuit for supplying current to the electric element is interrupted, and as a result, the supply of electric current to the electric element is stopped and the operation of the compressor is stopped.

JP-A-9-228963

In the protective device of Patent Document 1, if the factor causing the thermal deformation of the bimetal is eliminated, the shape of the bimetal returns to the shape before the thermal deformation, and the connection of the electric circuit is restored. As a result, the current supply to the electric element is resumed and the compressor is restarted. However, since it takes time to restore the shape of the bimetal, there is a problem that the compressor cannot be quickly restarted, and the comfort of the air conditioning controlled by the air conditioner is impaired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an air conditioner with improved air-conditioning comfort.

An air conditioner according to the present invention comprises a compressor, temperature detection means for detecting the temperature of an outer shell of the compressor, supply of current to the compressor according to temperature fluctuations of the outer shell of the compressor, and An air conditioner comprising: a thermal protector configured to stop current supply; and a control section for controlling current supply to the compressor, wherein the control section is detected by the temperature detection means. and the thermal protector is configured to stop current supply to the compressor when the temperature of the shell to which the temperature is applied reaches a preset stop temperature or higher, and the thermal protector is configured to stop the current supply to the compressor when the temperature of the shell is higher than the stop temperature. When it becomes above, the current supply to the compressor is stopped , and when the temperature of the outer shell falls to the restoration temperature lower than the operating temperature, the current supply to the compressor is performed, and the restoration temperature is the above-mentioned The air temperature is set higher than the upper limit of the air temperature at which the air conditioner operates, and the controller detects that the temperature of the outer shell becomes equal to or higher than the operating temperature, and the current supply to the compressor is stopped by the thermal protector. After that, the compressor is configured to stop driving until the temperature of the outer shell of the compressor detected by the temperature detecting means becomes equal to or lower than the restoration permission temperature which is lower than the restoration temperature .

According to the air conditioner of the present invention, the current supply to the compressor is stopped when the outer temperature of the compressed air becomes lower than the operating temperature of the thermal protector. Therefore, if the temperature of the compressor rises differently than usual, the compressor is stopped before the thermal protector operates. That is, the compressor is stopped without interrupting the current supply circuit due to the operation of the thermal protector. Therefore, when the temperature of the outer shell of the compressor drops below the stop temperature and the compressor is restarted, the compressor is quickly restarted. As a result, the comfort of the air conditioning control by the air conditioner 1 is improved.

2 is a refrigerant circuit diagram of the air conditioner according to Embodiment 1. FIG. 4 is a flow chart showing the operation of the compressor in the air conditioner according to Embodiment 1. FIG. 10 is a flow chart showing the operation of the compressor in the air conditioner according to Embodiment 3. FIG. 10 is a timing chart showing operation modes of a compressor and a thermal protector in an air conditioner according to Embodiment 3. FIG. FIG. 10 is a refrigerant circuit diagram of an air conditioner according to Embodiment 4; 14 is a flow chart showing a processing procedure after stopping the compressor in the air conditioner according to Embodiment 4. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of an air conditioner according to the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and various modifications can be made without departing from the gist of the present invention. In addition, the present invention includes all possible combinations of the configurations shown in the following embodiments. Further, the air conditioner shown in the drawings is an example of equipment to which the air conditioner of the present invention is applied, and the air conditioner of the present invention is not limited by the air conditioner shown in the drawings. do not have.

Embodiment 1.
1 is a refrigerant circuit diagram of an air conditioner according to Embodiment 1. FIG. The air conditioner 1 has an outdoor unit 2 , an indoor unit 3 and a controller 4 . The outdoor unit 2 has a compressor 21 , a flow path switching section 22 , an outdoor heat exchanger 23 , a first expansion valve 24 and a refrigerant container 25 . The indoor unit 3 has an indoor heat exchanger 31 and a second expansion valve 32 . A refrigerant circuit 5 is formed by the compressor 21, the flow path switching unit 22, the outdoor heat exchanger 23, the first expansion valve 24, the second expansion valve 32, the refrigerant container 25, the indoor heat exchanger 31, and the refrigerant piping. there is

The compressor 21 sucks refrigerant and compresses the sucked refrigerant into a high-temperature and high-pressure state. For example, by arbitrarily changing the operating frequency using an inverter circuit or the like, the capacity of the compressor 21, that is, the amount of refrigerant sent out per unit time is changed. A thermal protector 60 and a thermistor 70 are provided on the outer shell of the compressor 21 .

The thermal protector 60 is configured to supply current to the compressor 21 and stop the current supply in response to temperature fluctuations in the outer shell temperature of the compressor 21 . The thermal protector 60 has a bimetal (not shown) that is thermally deformed by an increase in ambient temperature and returns to its original shape when the increased ambient temperature decreases. The bimetal is connected to a current supply circuit that supplies current to the compressor 21 from a commercial power supply. The bimetal is configured to deform when the outer shell temperature of the compressor 21 rises to a predetermined temperature or higher. When the bimetal is thermally deformed, the current supply circuit is disconnected and becomes an open circuit, stopping the current supply to the compressor 21 . In addition, when the temperature of the outer shell of the compressor 21 that has risen falls to a predetermined temperature or less, the bimetal returns to its original shape, the cut current supply circuit is reconnected to form a closed circuit, and the current to the compressor 21 is restored. Supply resumes. In the following description, the deformation of the bimetal and opening of the current supply circuit of the thermal protector 60 is called the operation of the thermal protector 60, and the value of the temperature at which the thermal protector 60 operates is called the operating temperature. The operating temperature is set higher than the stop temperature of the compressor 21, which will be described later. When the bimetal returns to its original shape and the thermal protector 60 closes the current supply circuit, it is called the thermal protector 60 recovering, and the temperature at which the thermal protector 60 recovers is called the recovery temperature.

The thermistor 70 is temperature detection means for detecting the outer shell temperature of the compressor 21 .

The channel switching unit 22 switches the flow of refrigerant in the refrigerant circuit 5, and is, for example, a four-way valve. The flow path switching section 22 is controlled by the control section 4 .

The outdoor heat exchanger 23 exchanges heat between the refrigerant and outdoor air, that is, gas, and functions as a condenser during cooling operation and as an evaporator during heating operation. Outdoor air is supplied to the outdoor heat exchanger 13 by a fan (not shown).

The first expansion valve 14 and the second expansion valve 15 are valves that reduce the pressure of the refrigerant flowing through the refrigerant circuit 5, and are electronic expansion valves whose opening degree can be adjusted. The refrigerant container 25 is a surplus refrigerant storage container that is provided between the first expansion valve 24 and the second expansion valve 32 and stores surplus refrigerant.

The indoor heat exchanger 31 exchanges heat between the refrigerant and indoor air, that is, gas, and functions as an evaporator during cooling operation and as a condenser during heating operation. Indoor air is supplied to the indoor heat exchanger 31 by a fan (not shown).

The control unit 4 is composed of dedicated hardware or a CPU (Central Processing Unit) that executes a program stored in a memory. Note that the CPU is also called a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, or a processor.

When the control unit 4 is dedicated hardware, the control unit 4 is, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. Applicable. Each of the functional units realized by the control unit 4 may be realized by separate hardware, or each functional unit may be realized by one piece of hardware.

When the control unit 4 is a CPU, each function executed by the control unit 4 is implemented by software, firmware, or a combination of software and firmware. Software and firmware are written as programs and stored in memory. The CPU implements each function of the control unit 4 by reading and executing programs stored in the memory. Here, the memory is, for example, non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM or EEPROM.

A part of the functions of the control unit 4 may be realized by dedicated hardware, and a part thereof may be realized by software or firmware.

In FIG. 1, the flow of the refrigerant during the cooling operation is indicated by the solid line, and the flow of the refrigerant during the heating operation is indicated by the dashed line.

2 is a flowchart showing the operation of the compressor in the air conditioner according to Embodiment 1. FIG. In step S<b>1 , the compressor 21 is started under the control of the control unit 4 . Next, in step S2, the control unit 4 checks the detection result of the thermistor 70 to confirm whether or not the outer shell temperature of the compressor 21 is equal to or higher than the stop temperature. In Embodiment 1, the stop temperature is a preset value within the permissible range of the outer shell temperature of the compressor 21 and is set lower than the above-described operating temperature of the thermal protector 60 . When it is confirmed that the external temperature of the compressor 21 detected by the thermistor 70 is equal to or higher than the stop temperature, the process proceeds to step S3, and the driving of the compressor 21 is stopped under the control of the control section 4.

After the compressor 21 is stopped in step S3, the process proceeds to step S4. In step S4, the control unit 4 checks the detection result of the thermistor 70 to confirm whether the outer shell temperature of the compressor 21 is lower than the stop temperature. When it is confirmed that the external temperature of the compressor 21 detected by the thermistor 70 is lower than the stop temperature, the process returns to step S1, and the compressor 21 is restarted under the control of the controller 4.

In step S4, when it is confirmed by the control unit 4 that the outer shell temperature of the compressor 21 has not decreased to a temperature lower than the stop temperature, the process of step S4 is repeated.

In step S2, if it is confirmed that the external temperature of the compressor 21 detected by the thermistor 70 has not reached the stop temperature, the process does not proceed to step S3, and the compressor 21 is maintained in a driven state. After that, when the outer shell temperature of the compressor 21 rises and becomes equal to or higher than the operating temperature of the thermal protector 60 (YES in step S5), the above-mentioned bimetal of the thermal protector 60 is thermally deformed, and current is supplied to the compressor 21. is stopped. As a result, the compressor 21 is stopped (step S7).

In the state in which it is determined in step S2 that the outer shell temperature of the compressor 21 is lower than the stop temperature, the case where the outer shell temperature of the compressor 21 is equal to or higher than the operating temperature of the thermal protector 60 is, for example, when the thermistor 70 It is assumed that it has fallen off due to some reason. Further, when the control unit 4 is a CPU and each function executed by the control unit 4 is implemented by software, firmware, or a combination of software and firmware, abnormal termination of the software is assumed.

In step S2, it is confirmed that the outer shell temperature of the compressor 21 has not reached the stop temperature, the compressor 21 is maintained in a driven state, and the state in which the outer shell temperature of the compressor 21 is lower than the operating temperature of the thermal protector 60 is reached. If so, the process of step S6 is executed. In step S6, the control unit 4 checks the detection result of the thermistor 70 to confirm whether or not the outer shell temperature of the compressor 21 is lower than the stop temperature. If it is confirmed in step S6 that the outer shell temperature of the compressor 21 is equal to or higher than the stop temperature, the process returns to step S2, and the processes after step S2 are repeated. When it is confirmed in step S6 that the outer shell temperature of the compressor 21 is lower than the stop temperature, the process of step S6 is repeated.

If the temperature of the outer shell of the compressor 21 continues to be lower than the stop temperature after the compressor 21 is driven in step S1, the result is NO in step S2, NO in step S5, and YES in step S6. , the driving of the compressor 21 is maintained.

In Embodiment 1, the stop temperature is set lower than the operating temperature. Therefore, even if the outer shell temperature of the compressor 21 rises after the compressor 21 is started, the thermal protector 60 will not operate before the process of step S2 is executed.

In Embodiment 1, the stop temperature is set lower than the operating temperature of thermal protector 60 . Therefore, when the temperature of the outer shell of the compressor 21 rises differently than usual, the compressor 21 is driven by the controller 4 based on the detection result of the temperature detection means 20 before the thermal protector 60 operates. is stopped. In this case, the operation of the thermal protector 60 does not interrupt the current supply circuit, and the compressor 21 is stopped. Therefore, when the temperature of the outer shell of the compressor 21 drops below the stop temperature and the compressor 21 is restarted by the controller 4 (YES in step S4), the compressor 21 is quickly restarted. will be As a result, the comfort of the air conditioning control by the air conditioner 1 is improved.

Embodiment 2.
The air conditioner according to Embodiment 2 has a refrigerant circuit similar to the refrigerant circuit shown in FIG. In Embodiment 2, the return temperature of the thermal protector 60 described above is set higher than the upper limit of the air temperature at which the air conditioner 1 operates.

If the return temperature of the thermal protector 60 is lower than the upper limit of the air temperature at which the air conditioner 1 operates, the compressor 21 cannot be restarted once the thermal protector 60 operates. For example, if the return temperature of the thermal protector 60 is set to 10°C, when the thermal protector 60 operates in an environment where the air temperature is kept around 30°C, , the thermal protector 60 does not reset. Therefore, in order to control the air conditioning of the air conditioner 1, the thermal protector 60 needs to be replaced.

However, by setting the return temperature of the thermal protector 60 higher than the upper limit value of the air temperature at which the air conditioner 1 operates, the thermal protector 60 can be operated under the environment of the air temperature at which the air conditioner 1 operates. Afterwards, the compressor 21 can be restarted. For example, if the upper limit of the air temperature at which the air conditioner 1 operates is 52°C, the thermal protector 60 is configured so that the return temperature is higher than 52°C. As a result, even if the thermal protector 60 operates under any air temperature environment, the thermal protector 60 first recovers in the process of decreasing the air temperature to the operating temperature of the air conditioner 1 . Therefore, the phenomenon that the compressor 21 is not restarted even though the air conditioner 1 is operating is avoided. Therefore, according to the second embodiment, when the air temperature drops after the thermal protector 60 operates, stagnation of the air conditioning control by the air conditioner 1 is suppressed.

Embodiment 3.
3 is a flowchart showing the operation of the compressor in the air conditioner according to Embodiment 3. FIG. The air conditioner according to Embodiment 3 has a refrigerant circuit similar to the refrigerant circuit shown in FIG. In Embodiment 3, the restart of the compressor 21 is controlled based on the return permission temperature set lower than the above-described return temperature. As described above, when the outer shell temperature of the compressor 21 rises above the operating temperature of the thermal protector 60, the thermal protector 60 operates and the compressor 21 stops (step S11). After that, when the outer shell temperature of the compressor 21 becomes equal to or lower than the restoration temperature of the thermal protector 60 (YES in step S12), the process of step S13 is executed. After the compressor 21 stops, if the outer shell temperature of the compressor 21 continues to be higher than the return temperature (NO in step S12), the process of step S13 is not executed.

In step S13, the controller 4 keeps the compressor 21 stopped. When the process proceeds to step S13, the external temperature of the compressor 21 becomes equal to or lower than the restoration temperature, the bimetal of the thermal protector 60 returns to its original shape, and the circuit supplying current to the compressor 21 becomes a closed circuit. This is the case. Therefore, the compressor 21 is started again as it is. However, in the third embodiment, even if the circuit that supplies current to the compressor 21 is closed, the control unit 4 keeps the compressor 21 stopped.

The process then proceeds to step S14. In step S14, the detection result of the thermistor 70 is checked by the control unit 4 to confirm whether or not the outer shell temperature of the compressor 21 is equal to or lower than the restoration permission temperature. In Embodiment 3, the recovery permission temperature is set to a value lower than the recovery temperature of the thermal protector 60 . When it is confirmed that the outer shell temperature of the compressor 21 has decreased and is equal to or lower than the restoration permission temperature, the process proceeds to step S15. In step S<b>15 , processing for restarting the compressor 21 is executed by the control unit 4 . If it is confirmed in step S14 that the outer shell temperature of the compressor 21 is still higher than the restoration permission temperature, the process returns to step S12.

FIG. 4 is a timing chart showing operation modes of a compressor and a thermal protector in an air conditioner according to Embodiment 3. FIG. At time T1, from a state in which the external temperature of the compressor 21 is lower than the operating temperature, the thermal protector 60 is not operating, the current supply circuit is a closed circuit, and the compressor 21 is being started, the compressor 21 outer shell temperature begins to rise. Then, when the outer shell temperature of the compressor 21 continues to rise and becomes equal to or higher than the operating temperature at time T2, the thermal protector 60 is activated. As a result, the current supply circuit becomes an open circuit, and the driving of the compressor 21 is stopped.

After that, the outer shell temperature of the compressor 21 begins to decrease, and when the outer shell temperature detected by the temperature detection means 20 at time T3 becomes equal to or lower than the recovery temperature, the operation of the thermal protector 60 is terminated, and the current supply circuit is closed. . As described above, in the third embodiment, even if the current supply circuit is closed, the control unit 4 keeps the compressor 21 stopped. Then, when it is confirmed at time T4 that the outer shell temperature of the compressor 21 has fallen below the recovery permission temperature, the compressor 21 is restarted by the controller 4 .

When the operating temperature and the recovery temperature of the thermal protector 60 are close to each other, the thermal protector 60 operates and the thermal protector 60 recovers before the external temperature of the compressor 21 is sufficiently lowered even if the compressor 21 is stopped. The heated state of the compressor 21 may be maintained. According to the third embodiment, when the outer shell temperature of the compressor 21 rises, the thermal protector 60 operates, and the compressor 21 stops, the outer shell temperature of the compressor 21 is set lower than the recovery temperature. The compressor 21 is kept stopped until the temperature drops to the recovery permission temperature. Therefore, restarting of the compressor 21 while the heated state of the compressor 21 is maintained is suppressed.

Embodiment 4.
5 is a refrigerant circuit diagram of an air conditioner according to Embodiment 4. FIG. The air conditioner according to Embodiment 4 has a refrigerant circuit similar to the refrigerant circuit shown in FIG. The air conditioner 100 according to Embodiment 4 includes a display device 42 and a pressure switch 61 for the compressor 21 . The display device 42 may be provided in the remote controller of the indoor unit 3 or may be provided in a device (not shown) that monitors the operation of the air conditioner 100 . The pressure switch 61 is a protection device for protecting the compressor 21 and is connected in series with the thermal protector 60 in a current supply circuit that supplies current to the compressor 21 . This pressure switch 61 turns off when the pressure on the discharge side of the compressor 21 rises to a predetermined value, cuts off the current supply circuit, and turns on when the pressure on the discharge side of the compressor 21 is lower than the predetermined value. The current supply circuit is configured to be a closed circuit. The pressure switch 61 has a protective function of driving and stopping the compressor 21 based on the level of the pressure on the discharge side of the compressor 21 .

FIG. 6 is a flowchart showing a processing procedure after stopping the compressor in the air conditioner according to the fourth embodiment. When the driving of the compressor 21 is stopped in step S21, the process proceeds to step S22. In step S22, the controller 4 checks whether or not a preset time has elapsed since the compressor 21 was stopped. Normally, the rate of decrease in the outer shell temperature of the compressor 21 is slower than the rate of decrease in pressure on the discharge side of the compressor 21 , so the return of the pressure switch 61 is faster than the return of the thermal protector 60 . The above set time is set longer than the time required for the pressure switch 61 to return from off to on and shorter than the time required for the external temperature of the compressor 21 to drop below the return temperature. In the fourth embodiment, the set time is set to 3 minutes. If it is confirmed that the set time has passed since the compressor 21 stopped, the process proceeds to step S23. In step S<b>23 , the control unit 4 transmits a control signal for restarting the compressor 21 .

Next, in step S24, the controller 4 checks whether the compressor 21 can be restarted. If it is confirmed that the compressor 21 can be restarted, the process proceeds to step S25, and the compressor 21 is restarted in step S25.

If it is confirmed in step S24 that the compressor 21 cannot be restarted, the process proceeds to step S26. As described above, the pressure switch 61 is connected in series with the thermal protector 60, and the set time is set longer than the time required for the pressure switch 61 to return from off to on. Therefore, the pressure switch 61 is turned on when the set time has elapsed. When the compressor 21 cannot be restarted even though the pressure switch 61 is on, the thermal protector 60 is operating and the protective function of the pressure switch 61 is not operating. It can be determined that there is Therefore, in step S26, the control unit 4 displays on the display device 42 that the stop of the compressor 21 is due to the operation of the thermal protector 60. FIG.

According to the fourth embodiment, it becomes easy to identify the cause of the abnormal operation of stopping the compressor 21 .

1 air conditioner 2 outdoor unit 3 indoor unit 4 control unit 5 refrigerant circuit 13 outdoor heat exchanger 14 first expansion valve 15 second expansion valve 20 temperature detection means 21 compressor 22 flow Path switching unit 23 outdoor heat exchanger 24 first expansion valve 25 refrigerant container 31 indoor heat exchanger 32 second expansion valve 42 display device 60 thermal protector 61 pressure switch 70 thermistor 100 air conditioner Device.

Claims (2)

a compressor;
temperature detection means for detecting the temperature of the outer shell of the compressor;
a thermal protector configured to supply and stop current supply to the compressor according to temperature fluctuations of the outer shell of the compressor;
An air conditioner comprising a control unit that controls current supply to the compressor,
The control unit is configured to stop current supply to the compressor when the temperature of the outer shell detected by the temperature detection means reaches or exceeds a preset stop temperature,
The thermal protector stops current supply to the compressor when the temperature of the shell reaches an operating temperature higher than the stop temperature, and when the temperature of the shell drops to a recovery temperature lower than the operating temperature, the compression the return temperature is set higher than the upper limit of the air temperature at which the air conditioner operates,
After the temperature of the outer shell becomes equal to or higher than the operating temperature and the current supply to the compressor is stopped by the thermal protector, the temperature of the outer shell of the compressor detected by the temperature detecting means is and an air conditioner configured to stop driving the compressor until the temperature reaches a restoration permission temperature lower than the restoration temperature . Further comprising a protective device for the compressor,
In a current supply circuit that supplies current to the compressor, the thermal protector and the protection device are connected in series,
The control unit transmits a signal to restart the compressor after a set time has elapsed since the current supply to the compressor was stopped, and if the compressor cannot be restarted, the compressor 2. The air conditioner according to claim 1 , configured to notify that the cause of the stoppage of the machine is not due to the protective device but due to the operation of the thermal protector.

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