JP2013167438A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner with a blower fan to which a power from a fan motor is transmitted through a fan belt, the air conditioner configured to be capable of detecting presence of a fracture on the fan belt.SOLUTION: A physical quantity indicating a state of a refrigerant flowing in a heat exchanger is measured as a measurement value for determination. If a fan motor rotates during a refrigerating cycle and a determination condition is satisfied, that is, the measurement value for determination is out of a normal range in a state where a blowing fan is being driven by the fan motor during the refrigerating cycle for a specified period of time or more, a failure determination section determines presence of a fracture on a fan belt.

Description

  The present invention relates to an air conditioner including a blower fan in which power of a fan motor is transmitted via a fan belt.

  Conventionally, an air conditioner including a blower fan in which power of a fan motor is transmitted via a fan belt is known. This type of air conditioner is disclosed in Patent Document 1, for example.

  In the air conditioner of Patent Literature 1, an upstream chamber in which a hot water coil and a cold water coil are installed and a downstream chamber in which a blower fan and a duct are installed are formed in an air conditioner casing. A fan driving motor is linked to the blower fan via a fan belt.

JP-A-6-323564

  By the way, in this type of air conditioner, the fan belt may break due to a decrease in the strength of the fan belt due to deterioration. However, the conventional air conditioner cannot detect that the fan belt is broken even if the fan belt is broken.

  The present invention has been made in view of such points, and an object of the present invention is to break the fan belt in an air conditioner including a blower fan to which the power of the fan motor is transmitted via the fan belt. Is configured to be detectable.

  In the first invention, a compressor (30) and a heat exchanger (37) are provided, and a refrigerant circuit (20) for performing a refrigeration cycle by circulating a refrigerant and air to the heat exchanger (37) are provided. A blower fan (14) to be sent, a fan motor (28) for driving the blower fan (14), and a fan belt (29) for transmitting the power of the fan motor (28) to the blower fan (14) The air conditioner (10) provided with The air conditioner (10) includes a measuring unit (46, 48, 50) for measuring a physical quantity representing a state of the refrigerant flowing through the heat exchanger (37) as a measurement value for determination, and the refrigeration cycle. An abnormality determining means (55) for determining that the fan belt (29) is broken when a predetermined determination condition is satisfied when the fan motor (28) is rotating; The determination condition is that the determination measurement value is out of a normal range in which the blower fan (14) is driven by the fan motor (28) during the refrigeration cycle for a predetermined time or more. It is a condition that

  In 1st invention, a measurement means (46,48,50) measures the physical quantity showing the state of the refrigerant | coolant which flows through the heat exchanger (37) to which air is sent by the ventilation fan (14) as a measurement value for determination. The fan belt (29) is broken when the abnormality determination means (55) satisfies the determination condition that the determination measurement value is out of the normal range for a predetermined time or more in the fan motor rotating state. It is determined that Here, for example, in the case of the air conditioner (10) in which the heat exchanger (37) to which the air of the blower fan (14) is supplied operates as an evaporator, the blower fan (14) In the state driven by the fan motor (28), among the physical quantities representing the state of the refrigerant flowing through the heat exchanger (37), for example, the pressure of the low-pressure refrigerant sucked into the compressor (30) is a predetermined lower limit pressure. Higher than. That is, the range in which the pressure of the low-pressure refrigerant is higher than the lower limit pressure corresponds to the normal range. In such an air conditioner (10), when the blower fan (14) stops during the refrigeration cycle, the amount of heat absorbed by the refrigerant in the heat exchanger (37) is greatly reduced. As a result, the temperature of the refrigerant in the heat exchanger (37) is lowered, and the pressure of the low-pressure refrigerant becomes equal to or lower than the lower limit pressure and is out of the normal range. For example, in the case of the air conditioner (10) in which the heat exchanger (37) to which the air of the blower fan (14) is supplied operates as a radiator, the blower fan (14) is a fan during the refrigeration cycle. In the state driven by the motor (28), among the physical quantities representing the state of the refrigerant flowing through the heat exchanger (37), for example, the pressure of the high-pressure refrigerant discharged from the compressor (30) is, for example, a predetermined upper limit pressure Lower than. That is, the range in which the pressure of the high-pressure refrigerant is lower than the upper limit pressure corresponds to the normal range. In such an air conditioner (10), when the blower fan (14) stops during the refrigeration cycle, the amount of heat released from the refrigerant in the heat exchanger (37) is greatly reduced. As a result, the temperature of the refrigerant in the heat exchanger (37) rises, the pressure of the high-pressure refrigerant becomes equal to or higher than the upper limit pressure, and is out of the normal range. Thus, when the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) to which air is sent by the blower fan (14) is outside the normal range, the blower fan (14) is stopped. Is detected. Then, in the fan motor rotating state, the cause that the blower fan (14) is stopped is not the stop of the fan motor (28), so that it is detected that the fan belt (29) is broken. Therefore, in the first invention, the abnormality determination means (55) causes the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) to be out of the normal range for a predetermined time or more when the fan motor is rotating. The fan belt (29) is determined to be broken.

  According to a second invention, in the first invention, in the evaporation side refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the measuring means (46, 48, 50) includes the compressor (30 ) Is measured as the measurement value for determination, and the range in which the measurement value for determination is higher than a predetermined lower limit pressure is the normal range, while the refrigeration cycle in the evaporation side is The abnormality determination means (55) is configured to detect the fan when the condition that the measurement value for determination is equal to or lower than the lower limit pressure for a predetermined time or more is satisfied as the determination condition in the fan motor rotating state. It is determined that the belt (29) is broken.

  In the second invention, during the refrigeration cycle on the evaporation side, the pressure of the low-pressure refrigerant sucked into the compressor (30) in the rotational state of the fan motor has been lower than the lower limit pressure over a predetermined time. In this case, the abnormality determining means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) stops during the evaporation-side refrigeration cycle, the heat absorption amount of the refrigerant in the heat exchanger (37) is greatly reduced, and the pressure of the low-pressure refrigerant becomes lower than the lower limit pressure. In the second aspect of the invention, when performing the evaporation side refrigeration cycle, whether the blower fan (14) is stopped during the refrigeration cycle, whether the pressure of the low-pressure refrigerant is equal to or lower than the lower limit pressure. Whether or not the fan belt (29) is broken is determined using what can be determined in step (1).

  According to a third aspect of the present invention, in the second aspect of the present invention, in the evaporation side refrigeration cycle, the operating capacity of the compressor (30) is adjusted so that the determination measurement value is higher than the lower limit pressure, The abnormality determination means (55) in the evaporative refrigeration cycle has the determination measurement value less than a first low pressure reference value lower than the lower limit pressure over a predetermined time in the fan motor rotating state. The first low-pressure condition is set not only in the case where the determination condition is satisfied, but also in the low-capacity region where the operation capacity of the compressor (30) is controllable in the fan motor rotation state. When the second low-pressure condition is satisfied that the measurement value for determination is lower than the lower limit pressure and lower than the second low-pressure reference value higher than the first low-pressure reference value for a predetermined time or more in a state Even the above fan It determines that the belt (29) is broken.

  In the third invention, during the refrigeration cycle on the evaporation side, the first low pressure condition that the pressure of the low pressure refrigerant is less than the first low pressure reference value over a predetermined time in the fan motor rotating state; At least one of the second low-pressure conditions in which the pressure of the low-pressure refrigerant is less than the second low-pressure reference value for a predetermined time or longer with the operating capacity of the compressor (30) set in the low-capacity region. Is established, the abnormality determining means (55) determines that the fan belt (29) is broken. The second low pressure reference value is a value outside the normal range below the lower limit pressure, and is higher than the first low pressure reference value used in the first low pressure condition. Here, when the operating capacity of the compressor (30) is set to a high capacity range that can be controlled, the pressure of the low-pressure refrigerant may increase when the operating capacity of the compressor (30) is reduced. There is. For this reason, regardless of the operating capacity of the compressor (30), the pressure of the low-pressure refrigerant is increased in the first low-pressure condition for determining whether or not the fan belt (29) is broken. Since it is not known how much the adjustment range of the operating capacity of the compressor (30) is left, in consideration of the possibility that the pressure of the low-pressure refrigerant will rise, the first low-pressure standard that is the judgment threshold value of the low-pressure refrigerant It is necessary to set a value. On the other hand, in the second low pressure condition in which it is determined that the belt has run out while the compressor (30) is set to the low capacity region, there is not much adjustment range of the operating capacity of the compressor (30). I know. For this reason, the second low pressure reference value is set to a value higher than the first low pressure reference value. Therefore, it can be detected that the fan belt (29) is broken more quickly in the second low-pressure condition than in the first low-pressure condition with respect to the decrease in the pressure of the low-pressure refrigerant. On the other hand, when the fan belt (29) breaks, the pressure of the low-pressure refrigerant may become less than the first low-pressure reference value before the operating capacity of the compressor (30) becomes the low-capacity region. In such a case, it can be quickly detected that the fan belt (29) is broken in the first low pressure condition than in the second low pressure condition. In the third aspect of the invention, when the operating capacity of the compressor (30) does not immediately drop to the low capacity region after the fan belt (29) is broken, the fan belt (29) is quickly detected. A first low-pressure condition that can be detected and a second low-pressure condition that can quickly detect that the fan belt (29) is broken as the pressure of the low-pressure refrigerant is reduced are used to determine whether the belt has run out.

  In a fourth aspect based on the first aspect, in the refrigeration cycle on the evaporation side in which the heat exchanger (37) operates as an evaporator, the measuring means (46, 48, 50) includes the heat exchanger ( 37) the refrigerant evaporation temperature in 37) is measured as the determination measurement value, and the range in which the determination measurement value is higher than a predetermined lower limit temperature is the normal range, while the abnormality determination in the evaporation side refrigeration cycle is performed. The means (55) is configured so that when the condition that the measured value for determination is equal to or lower than the lower limit temperature for a predetermined time or more is satisfied as the determination condition in the fan motor rotating state, the fan belt ( It is determined that 29) is broken.

  In the fourth invention, when performing the evaporation side refrigeration cycle, it is possible to determine whether or not the blower fan (14) is stopped during the refrigeration cycle based on whether or not the evaporation temperature is lower than the lower limit temperature. Is used to determine whether the fan belt (29) is broken or not.

  In a fifth aspect based on the fourth aspect, the operating capacity of the compressor (30) is adjusted so that the determination measurement value is higher than the lower limit temperature in the evaporation side refrigeration cycle, The abnormality determination means (55) in the evaporation side refrigeration cycle has the measurement value for determination below the first low temperature reference value lower than the lower limit temperature over a predetermined time in the fan motor rotating state. The first low-temperature condition is set not only in the case where the determination condition is satisfied, but also in the low-capacity region where the operation capacity of the compressor (30) is controllable in the fan motor rotation state. A second low temperature condition is satisfied that the measured value for determination is lower than the lower limit temperature and lower than a second low temperature reference value higher than the first low temperature reference value for a predetermined time or more in a state Even the above fan It determines that the belt (29) is broken.

  In the fifth aspect of the invention, during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the evaporation temperature becomes lower than the first low temperature reference value for a predetermined time or more in the fan motor rotating state. A first low temperature condition that the operation temperature of the compressor (30) is set in a low capacity region, and a second evaporating temperature is equal to or lower than a second low temperature reference value over a predetermined time. When at least one of the low temperature conditions is satisfied, the abnormality determining means (55) determines that the fan belt (29) is broken. The second low temperature reference value is a value outside the normal range below the lower limit temperature, and is higher than the first low temperature reference value used in the first low temperature condition. According to the fifth aspect of the invention, when the operating capacity of the compressor (30) does not immediately fall to the low capacity region after the fan belt (29) is broken, it is detected that the fan belt (29) is broken quickly. A first low-temperature condition that can be detected and a second low-temperature condition that can quickly detect that the fan belt (29) is broken in response to a decrease in the evaporation temperature are used for the determination of belt breakage.

  In a sixth aspect based on the first aspect, in the refrigeration cycle on the heat radiating side where the heat exchanger (37) operates as a radiator, the measuring means (46, 48, 50) includes the compressor (30 ) Is measured as the measurement value for determination, and the range in which the measurement value for determination is lower than a predetermined upper limit pressure is the normal range, while the refrigeration cycle in the heat radiation side is The abnormality determining means (55) is configured to detect the fan when the condition that the measured value for determination is equal to or higher than the upper limit pressure for a predetermined time or more is satisfied as the determination condition in the fan motor rotating state. It is determined that the belt (29) is broken.

  In the sixth invention, the pressure of the high-pressure refrigerant discharged from the compressor (30) in the fan motor rotating state during the refrigeration cycle on the heat dissipation side is equal to or higher than the upper limit pressure over a predetermined time. In this case, the abnormality determining means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) is stopped during the refrigeration cycle on the heat radiation side, the heat radiation amount of the refrigerant in the heat exchanger (37) is greatly reduced, and the pressure of the high-pressure refrigerant becomes equal to or higher than the upper limit pressure. In the sixth aspect of the invention, when the refrigeration cycle on the heat radiation side is performed, whether the blower fan (14) is stopped during the refrigeration cycle, whether the pressure of the high-pressure refrigerant is equal to or higher than the upper limit pressure. Whether or not the fan belt (29) is broken is determined using what can be determined in step (1).

  In a seventh aspect based on the sixth aspect, the operating capacity of the compressor (30) is adjusted in the refrigeration cycle on the heat radiation side so that the measurement value for determination is lower than the upper limit pressure, The abnormality determining means (55) in the refrigeration cycle on the heat release side is said that the determination measurement value exceeds a first high pressure reference value higher than the upper limit pressure over a predetermined time in the fan motor rotating state. Not only when the first high-pressure condition is satisfied as the determination condition, but also in a state where the fan motor is rotated and the operating capacity of the compressor (30) is set in a controllable low-capacity region. The fan belt also when the second high pressure condition that the measured value for determination exceeds the upper limit pressure for a predetermined time or more and exceeds a second high pressure reference value lower than the first high pressure reference value is satisfied. (29) broke It is determined to be.

  In the seventh aspect of the invention, during the refrigeration cycle on the heat radiation side, the first high pressure condition that the pressure of the high pressure refrigerant exceeds the first high pressure reference value for a predetermined time or more in the rotation state of the fan motor; When at least one of the second high pressure condition that the pressure of the high pressure refrigerant exceeds the second high pressure reference value for a predetermined time or more with the operation capacity of 30) set in the low capacity region is satisfied, The abnormality determining means (55) determines that the fan belt (29) is broken. The second high pressure reference value is a value outside the normal range above the upper limit pressure, and is lower than the first high pressure reference value used in the first high pressure condition. Here, when the operating capacity of the compressor (30) is set in a high capacity range that is controllable, the pressure of the high-pressure refrigerant may decrease if the operating capacity of the compressor (30) is reduced. There is. Therefore, regardless of the operating capacity of the compressor (30), the pressure of the high-pressure refrigerant is decreased under the first high-pressure condition for determining whether or not the fan belt (29) is broken. Since it is not known how much the adjustment range of the operating capacity of the compressor (30) is left, in consideration of the possibility that the pressure of the high-pressure refrigerant will decrease, the first high-pressure reference which is the judgment threshold value of the pressure of the high-pressure refrigerant It is necessary to set a value. On the other hand, in the second high pressure condition in which it is determined that the belt has run out while the compressor (30) is set in the low capacity region, the operating capacity adjustment range of the compressor (30) does not remain so much. I know. For this reason, the second high pressure reference value is set to a value lower than the first high pressure reference value. Therefore, with respect to the increase in the pressure of the high-pressure refrigerant, it can be quickly detected that the fan belt (29) is broken under the second high-pressure condition rather than the first high-pressure condition. On the other hand, when the fan belt (29) breaks, the pressure of the high-pressure refrigerant may become equal to or higher than the first high-pressure reference value before the operating capacity of the compressor (30) becomes the low capacity region. In such a case, it can be quickly detected that the fan belt (29) is broken under the first high pressure condition than under the second high pressure condition. According to the seventh aspect of the invention, when the operating capacity of the compressor (30) does not immediately fall to the low capacity region after the fan belt (29) is broken, it is detected that the fan belt (29) is broken quickly. The first high-pressure condition that can be detected and the second high-pressure condition that can quickly detect that the fan belt (29) is broken as the pressure of the high-pressure refrigerant rises are used to determine whether the belt has run out.

  In an eighth aspect based on the first aspect, in the refrigeration cycle on the heat radiating side in which the heat exchanger (37) operates as a radiator, the measuring means (46, 48, 50) includes the heat exchanger ( 37) the refrigerant condensing temperature is measured as the determination measurement value, and the range in which the determination measurement value is lower than a predetermined upper limit temperature is the normal range, while the abnormality determination in the refrigeration cycle on the heat release side is performed. The means (55) is configured so that the fan belt (if the condition that the measured value for determination is equal to or higher than the upper limit temperature for a predetermined time or more is satisfied as the determination condition in the fan motor rotation state). It is determined that 29) is broken.

  In the eighth invention, when performing the refrigeration cycle on the heat dissipation side, it can be determined whether or not the blower fan (14) is stopped during the refrigeration cycle based on whether or not the condensation temperature is equal to or higher than the upper limit temperature. Is used to determine whether the fan belt (29) is broken or not.

  In a ninth aspect based on the eighth aspect, the operating capacity of the compressor (30) is adjusted in the refrigeration cycle on the heat release side so that the determination measurement value is lower than the upper limit temperature. The abnormality determining means (55) in the refrigeration cycle on the heat radiation side is said that the determination measurement value exceeds the first high temperature reference value higher than the upper limit temperature over a predetermined time in the fan motor rotating state. Not only when the first high temperature condition is satisfied as the determination condition, but also in the fan motor rotating state and in a state where the operating capacity of the compressor (30) is set to a controllable low capacity region, The fan belt also when the second high temperature condition that the measured value for determination exceeds the upper limit temperature for a predetermined time or more and exceeds the second high temperature reference value lower than the first high temperature reference value is satisfied. (29) broke It is determined to be.

  In the ninth aspect of the present invention, during the refrigeration cycle on the heat dissipation side, the first high temperature condition that the condensation temperature exceeds the first high temperature reference value for a predetermined time or more in the rotation state of the fan motor, and compression At least one of the second high temperature conditions that the condensing temperature exceeds the second high temperature reference value for a predetermined time or more with the operating capacity of the machine (30) set in the low capacity region is established. In this case, the abnormality determining means (55) determines that the fan belt (29) is broken. The second high temperature reference value is a value outside the normal range above the upper limit temperature, and is lower than the first high temperature reference value used in the first high temperature condition. According to the ninth aspect of the present invention, when the operating capacity of the compressor (30) does not immediately fall to the low capacity region after the fan belt (29) is broken, the fan belt (29) is quickly detected. The first high temperature condition that can be detected and the second high temperature condition that can quickly detect that the fan belt (29) is broken as the condensing temperature rises are used to determine whether the belt has run out.

  A tenth aspect of the invention is provided with a refrigerant circuit (20) in which a compressor (30) and a heat exchanger (37) having a variable operating capacity are provided to perform a refrigeration cycle by circulating a refrigerant, and the heat exchanger ( 37) A blower fan (14) for sending air to the fan, a fan motor (28) for driving the blower fan (14), and a fan for transmitting the power of the fan motor (28) to the blower fan (14) The target is an air conditioner (10) provided with a belt (29). The air conditioner (10) includes a measuring unit (46, 48, 50) for measuring a physical quantity representing a state of the refrigerant flowing through the heat exchanger (37) as a measurement value for determination, and the refrigeration cycle. The operating capacity of the compressor (30) is adjusted so that the determination measurement value is within a predetermined normal range, and when the determination measurement value is out of the normal range, the compressor (30) An operation control means (54) for reducing the operation capacity, a fan motor rotating state in which the fan motor (28) is rotating during the refrigeration cycle, and a range in which the operation capacity of the compressor (30) can be controlled. An abnormality determining means (55) for determining that the fan belt (29) is broken when a predetermined determination condition is satisfied in a low capacity state set in a low capacity region, The measurement value for judgment is in the normal range over a predetermined time. It is a condition that is out et al.

  In the tenth invention, the measuring means (46, 48, 50) measures the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) to which air is sent by the blower fan (14) as the measurement value for determination. When the abnormality determination means (55) is in the fan motor rotating state and in the low capacity state, and the determination condition that the determination measurement value is out of the normal range for a predetermined time or more is satisfied, the fan belt It is determined that (29) is broken. Here, for example, in the case where the heat exchanger (37) to which the air of the blower fan (14) is supplied is an air conditioner (10) operating as an evaporator, the refrigerant flowing through the heat exchanger (37) Among the physical quantities representing this state, for example, the operating capacity of the compressor (30) is adjusted such that the pressure of the low-pressure refrigerant sucked into the compressor (30) is higher than a predetermined lower limit pressure. That is, the range in which the pressure of the low-pressure refrigerant is higher than the lower limit pressure corresponds to the normal range. In such an air conditioner (10), when the blower fan (14) stops during the refrigeration cycle, the amount of heat absorbed by the refrigerant in the heat exchanger (37) is greatly reduced. As a result, the temperature of the refrigerant in the heat exchanger (37) is lowered, and the pressure of the low-pressure refrigerant becomes equal to or lower than the lower limit pressure and is out of the normal range. When the pressure of the low-pressure refrigerant decreases, the operation control means (54) decreases the operating capacity of the compressor (30) in an attempt to increase the pressure of the low-pressure refrigerant. For example, in the case of the air conditioner (10) in which the heat exchanger (37) to which the air of the blower fan (14) is supplied operates as a radiator, the refrigerant flowing through the heat exchanger (37) Of the physical quantity representing the state, for example, the operating capacity of the compressor (30) is adjusted such that the pressure of the high-pressure refrigerant discharged from the compressor (30) is lower than a predetermined upper limit pressure. That is, the range in which the pressure of the high-pressure refrigerant is lower than the upper limit pressure corresponds to the normal range. In such an air conditioner (10), when the blower fan (14) stops during the refrigeration cycle, the amount of heat released from the refrigerant in the heat exchanger (37) is greatly reduced. As a result, the temperature of the refrigerant in the heat exchanger (37) rises, the pressure of the high-pressure refrigerant becomes equal to or higher than the upper limit pressure, and is out of the normal range. When the pressure of the high-pressure refrigerant increases, the operation control means (54) decreases the operating capacity of the compressor (30) in an attempt to decrease the pressure of the high-pressure refrigerant. As described above, when the blower fan (14) is stopped, the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) to which air is sent by the blower fan (14) is out of the normal range, and the compressor (30). When the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) in the low capacity state falls outside the normal range, the blower fan (14) is in a stopped state. Is detected. Then, in the fan motor rotating state, the cause that the blower fan (14) is stopped is not the stop of the fan motor (28), so that it is detected that the fan belt (29) is broken. Therefore, in the tenth aspect of the present invention, the abnormality determination means (55) is such that the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is in a state where the fan motor is rotating and in a low capacity state for a predetermined time or more. When it is out of the normal range, it is determined that the fan belt (29) is broken.

  In an eleventh aspect based on the tenth aspect, in the refrigeration cycle on the evaporation side in which the heat exchanger (37) operates as an evaporator, the measuring means (46, 48, 50) includes the compressor (30 ) Is measured as the measurement value for determination, and the range in which the measurement value for determination is higher than a predetermined lower limit pressure is the normal range, while the refrigeration cycle in the evaporation side is The abnormality determination means (55) satisfies the condition that the measurement value for determination is not more than the lower limit pressure for a predetermined time or more in the fan motor rotating state and the low capacity state as the determination condition. In this case, it is determined that the fan belt (29) is broken.

  In the eleventh aspect of the invention, during the evaporation side refrigeration cycle, the pressure of the low-pressure refrigerant sucked into the compressor (30) is lower than the lower limit pressure over a predetermined time in the fan motor rotating state and in the low capacity state. When it is, the abnormality determining means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) stops during the evaporation-side refrigeration cycle, the heat absorption amount of the refrigerant in the heat exchanger (37) is greatly reduced, and the pressure of the low-pressure refrigerant becomes lower than the lower limit pressure. Moreover, the operating capacity of the compressor (30) decreases as the pressure of the low-pressure refrigerant decreases. In the eleventh aspect of the invention, when performing the evaporation side refrigeration cycle, whether or not the blower fan (14) is stopped during the refrigeration cycle is determined by the pressure of the low-pressure refrigerant and the operating capacity of the compressor (30). It is determined whether or not the fan belt (29) is broken by using what can be determined.

  In a twelfth aspect based on the tenth aspect, in the refrigeration cycle on the evaporation side in which the heat exchanger (37) operates as an evaporator, the measuring means (46, 48, 50) includes the heat exchanger ( 37) the refrigerant evaporation temperature in 37) is measured as the determination measurement value, and the range in which the determination measurement value is higher than a predetermined lower limit temperature is the normal range, while the abnormality determination in the evaporation side refrigeration cycle is performed. The means (55) is configured such that the condition that the measurement value for determination is not more than the lower limit temperature for a predetermined time or more is satisfied as the determination condition in the fan motor rotating state and the low capacity state. Then, it is determined that the fan belt (29) is broken.

  In the twelfth aspect of the invention, when performing the evaporation side refrigeration cycle, it can be determined from the evaporation temperature and the operating capacity of the compressor (30) whether or not the blower fan (14) is stopped during the refrigeration cycle. Using it, it is determined whether or not the fan belt (29) is broken.

  In a thirteenth aspect based on the tenth aspect, in the refrigeration cycle on the heat radiating side where the heat exchanger (37) operates as a radiator, the measuring means (46, 48, 50) includes the compressor (30 ) Is measured as the measurement value for determination, and the range in which the measurement value for determination is lower than a predetermined upper limit pressure is the normal range, while the refrigeration cycle in the heat radiation side is The abnormality determination means (55) satisfies the condition that the determination measurement value is equal to or higher than the upper limit pressure for a predetermined time or more in the fan motor rotating state and the low capacity state. In this case, it is determined that the fan belt (29) is broken.

  In the thirteenth aspect of the invention, the pressure of the high-pressure refrigerant discharged from the compressor (30) in the rotational state of the fan motor and in the low-capacity state during the refrigeration cycle on the heat radiation side exceeds the upper limit pressure over a predetermined time. When it is, the abnormality determining means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) is stopped during the refrigeration cycle on the heat radiation side, the heat radiation amount of the refrigerant in the heat exchanger (37) is greatly reduced, and the pressure of the high-pressure refrigerant becomes equal to or higher than the upper limit pressure. Moreover, the operating capacity of the compressor (30) decreases as the pressure of the high-pressure refrigerant increases. In the thirteenth aspect, when the refrigeration cycle on the heat radiation side is performed, whether or not the blower fan (14) is stopped during the refrigeration cycle is determined by the pressure of the high-pressure refrigerant and the operating capacity of the compressor (30). It is determined whether or not the fan belt (29) is broken by using what can be determined.

  In a fourteenth aspect based on the tenth aspect, in the refrigeration cycle on the heat radiating side in which the heat exchanger (37) operates as a radiator, the measuring means (46, 48, 50) includes the heat exchanger ( 37) the refrigerant condensing temperature is measured as the determination measurement value, and the range in which the determination measurement value is lower than a predetermined upper limit temperature is the normal range, while the abnormality determination in the refrigeration cycle on the heat release side is performed. The means (55) is configured such that a condition that the determination measurement value is equal to or higher than the upper limit temperature for a predetermined time or more in the fan motor rotating state and the low capacity state is satisfied as the determination condition. Then, it is determined that the fan belt (29) is broken.

  In the fourteenth aspect of the invention, when the refrigeration cycle on the heat radiation side is performed, it can be determined from the condensation temperature and the operating capacity of the compressor (30) whether or not the blower fan (14) is stopped during the refrigeration cycle. Using it, it is determined whether or not the fan belt (29) is broken.

  In a fifteenth aspect of the present invention, in the first or tenth aspect of the present invention, the heat exchanger (37) and the air blower fan (14) are accommodated in the casing (15). The blower fan (14) is arranged to form an air passage (31) through which air flows upward, while the abnormality determining means (55) is a refrigeration cycle in which the heat exchanger (37) operates as an evaporator. During the fan motor rotation state, not only when the determination condition is satisfied, but also in the fan motor rotation state, the temperature of the air below the heat exchanger (37) in the air passage (31) It is determined that the fan belt (29) is broken also when it becomes lower than a predetermined low-temperature air reference value over a period of time.

  In the fifteenth aspect of the present invention, even when the determination condition based on the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is not satisfied during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator, When the fan motor is rotating and the temperature of the air below the heat exchanger (37) in the air passage (31) is lower than the predetermined low-temperature air reference value for a predetermined time or more, an abnormality is determined. The means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the air cooled by the heat exchanger (37) moves downward in the air passage (31) To do. As a result, the temperature of the air below the heat exchanger (37) in the air passage (31) decreases. As the blower fan (14) stops, the temperature of the refrigerant in the heat exchanger (37) decreases, so the temperature of the air below the heat exchanger (37) decreases relatively. In the fifteenth aspect of the invention, when the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the temperature of the air below the heat exchanger (37) in the air passage (31) Focusing on a relatively large decrease in air flow, it is determined whether the fan belt (29) is broken based on the temperature change of the air below the heat exchanger (37) in the air passage (31). The

  According to a sixteenth aspect of the present invention, in the first or tenth aspect of the invention, the heat exchanger (37) and the fan (14) are accommodated in the casing (15) containing the heat exchanger (37) and the blower fan (14). The air fan (14) is arranged to form an air passage (31) through which air flows upward, while the abnormality determining means (55) is a refrigeration cycle in which the heat exchanger (37) operates as a radiator. During the rotation of the fan motor, the temperature of the air above the heat exchanger (37) in the air passage (31) It is determined that the fan belt (29) is broken also when it becomes higher than a predetermined high-temperature air reference value over a period of time.

  In the sixteenth invention, during the refrigeration cycle in which the heat exchanger (37) operates as a radiator, even if the determination condition based on the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is not satisfied, If the temperature of the air above the heat exchanger (37) in the air passage (31) becomes higher than a predetermined high-temperature air reference value for a predetermined time or more with the fan motor rotating, an abnormality is determined. The means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as a radiator, the air heated by the heat exchanger (37) moves upward in the air passage (31). Moving. As a result, the temperature of the air above the heat exchanger (37) in the air passage (31) increases. As the blower fan (14) stops, the temperature of the refrigerant in the heat exchanger (37) rises, so the temperature of the air above the heat exchanger (37) rises relatively large. In the sixteenth aspect of the invention, when the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as a radiator, the air above the heat exchanger (37) in the air passage (31) Focusing on the relatively large rise in temperature, it is determined whether the fan belt (29) is broken based on the temperature change of the air above the heat exchanger (37) in the air passage (31). Is done.

  In a seventeenth aspect based on the first or tenth aspect, a casing (15) that houses the blower fan (14) and the heat exchanger (37) includes the heat exchanger (37) and the heat exchanger (37). An air passage (31) in which a blower fan (14) is arranged is formed, and the air passage (31) is provided with a humidifying device (19) for imparting moisture to the air that has passed through the heat exchanger (37). On the other hand, the abnormality determining means (55) is configured such that, during the operation of the humidifier (19), the rate of increase of the humidity of the air passage (31) per unit time in a rotating state of the fan motor is a predetermined humidity reference value. If it becomes larger than that, it is determined that the fan belt (29) is broken without performing an operation of determining whether or not the determination condition is satisfied.

  In the seventeenth invention, during the operation of the humidifier (19), when the rate of increase of the humidity of the air passage (31) per unit time is larger than a predetermined humidity reference value in the fan motor rotating state, Without performing the operation of determining whether or not the determination condition is satisfied, the abnormality determination means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) stops during operation of the humidifier (19), the humidity of the air passage (31) gradually increases. In the seventeenth aspect of the invention, paying attention to the fact that the humidity of the air passage (31) increases when the blower fan (14) stops during operation of the humidifier (19), the unit of humidity of the air passage (31) Based on the rate of increase per hour, it is determined whether or not the fan belt (29) is broken.

  In an eighteenth aspect based on any one of the first to seventeenth aspects, the abnormality determining means (55) in the refrigeration cycle is a unit of a current value of a motor current supplied to the fan motor (28). When the rate of decrease per time is smaller than a predetermined current reference value, an operation is performed to determine whether or not the determination condition is satisfied.

  In the eighteenth invention, it is determined whether or not the determination condition is satisfied when the rate of decrease in the current value of the motor current supplied to the fan motor (28) per unit time is smaller than a predetermined current reference value. Is performed. Here, when the fan belt (29) is broken, the load of the fan motor (28) is reduced, so that the motor current is reduced. That is, according to the rate of change of the current value of the motor current, it can be determined to some extent whether or not the fan belt (29) is broken. Therefore, in the eighteenth aspect, it is determined whether or not to perform the above operation based on the rate of change of the current value of the motor current.

  In a nineteenth aspect based on any one of the first to seventeenth aspects, the abnormality determining means (55) in the refrigeration cycle has a reduction rate per unit time of the rotational speed of the blower fan (14). When the rotation speed is smaller than the predetermined rotation speed reference value, an operation is performed to determine whether or not the determination condition is satisfied.

  In the nineteenth invention, when the rate of decrease in the rotational speed of the blower fan (14) per predetermined time becomes smaller than a predetermined rotational speed reference value, an operation for determining whether or not the determination condition is satisfied is performed. Is called. Here, when the fan belt (29) breaks, the rotational speed of the blower fan (14) decreases. That is, according to the rate of change of the rotational speed of the blower fan (14), it can be determined to some extent whether or not the fan belt (29) is broken. Therefore, in the nineteenth aspect, it is determined whether or not to perform the above operation based on the rate of change of the rotational speed of the blower fan (14).

  In each of the first to ninth inventions, when the blower fan (14) is stopped, the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is out of the normal range. When the physical quantity representing the state of the refrigerant flowing through the container (37) is out of the normal range for a predetermined time or more, the abnormality determining means (55) determines that the fan belt (29) is broken. . Therefore, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized.

  In each of the second and fourth inventions, when the heat exchanger (37) performs a refrigeration cycle that operates as an evaporator, whether or not the blower fan (14) is stopped during the refrigeration cycle. However, the fan belt (29) is broken by using the fact that it can be judged whether or not the pressure of the low-pressure refrigerant is lower than the lower limit pressure (or the refrigerant evaporation temperature in the heat exchanger (37) is lower than the lower limit temperature). It is determined whether or not. For this reason, an air conditioner (10) capable of detecting that the fan belt (29) is broken is used as an air conditioner (10) that performs a refrigeration cycle in which the heat exchanger (37) operates as an evaporator. Can be realized.

  In the third and fifth inventions, the fan belt (29) is quickly broken when the operating capacity of the compressor (30) is not immediately reduced to the low capacity region after the fan belt (29) is broken. The condition that can detect that the fan belt is broken, and the condition that the fan belt (29) can be quickly detected that the fan belt (29) is broken in response to a decrease in the pressure of the low-pressure refrigerant (or a decrease in evaporation temperature) It is used for judgment. For this reason, even if the operating capacity of the compressor (30) immediately decreases to the low capacity area after the fan belt (29) breaks, it does not immediately decrease to the low capacity area. It is possible to quickly detect that the fan belt (29) is broken.

  Further, in each of the sixth and eighth inventions, when the heat exchanger (37) performs a refrigeration cycle that operates as a radiator, whether or not the blower fan (14) is stopped during the refrigeration cycle. However, the fan belt (29) is broken by using the fact that it can be determined whether or not the pressure of the high-pressure refrigerant is higher than the upper limit pressure (or the refrigerant condensing temperature in the heat exchanger (37) is higher than the upper limit temperature). It is determined whether or not. Therefore, an air conditioner (10) that can detect that the fan belt (29) is broken is realized as an air conditioner (10) that performs a refrigeration cycle in which the heat exchanger (37) operates as a radiator. can do.

  In the seventh and ninth inventions, the fan belt (29) is quickly broken when the operating capacity of the compressor (30) is not immediately reduced to the low capacity region after the fan belt (29) is broken. The condition that can detect that the fan belt is broken, and the condition that the fan belt (29) can be quickly detected that the fan belt (29) is broken in response to the increase in the pressure of the high-pressure refrigerant (or increase in evaporation temperature) It is used for judgment. For this reason, even if the operating capacity of the compressor (30) immediately decreases to the low capacity area after the fan belt (29) breaks, it does not immediately decrease to the low capacity area. It is possible to quickly detect that the fan belt (29) is broken.

  In each of the tenth to fourteenth inventions, when the blower fan (14) stops, the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is out of the normal range, and the compressor (30) Since the operating capacity is reduced, the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is in the normal range over a predetermined time when the abnormality determining means (55) is in the fan motor rotating state and in the low capacity state. When it is off, it is determined that the fan belt (29) is broken. Therefore, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized.

  In each of the eleventh and twelfth inventions, when the refrigeration cycle in which the heat exchanger (37) operates as an evaporator is performed, whether or not the blower fan (14) is stopped during the refrigeration cycle. However, it is determined whether or not the fan belt (29) is broken by using the fact that it can be determined from the pressure (or evaporation temperature) of the low-pressure refrigerant and the operating capacity of the compressor (30). For this reason, an air conditioner (10) capable of detecting that the fan belt (29) is broken is used as an air conditioner (10) that performs a refrigeration cycle in which the heat exchanger (37) operates as an evaporator. Can be realized.

  In each of the thirteenth and fourteenth inventions, when the heat exchanger (37) performs a refrigeration cycle that operates as a radiator, whether or not the blower fan (14) is stopped during the refrigeration cycle. However, it is determined whether or not the fan belt (29) is broken by using the fact that it can be determined from the pressure (or condensing temperature) of the high-pressure refrigerant and the operating capacity of the compressor (30). For this reason, the air conditioner (10) capable of detecting that the fan belt (29) is broken is used as the air conditioner (10) for performing the refrigeration cycle in which the heat exchanger (37) operates as a radiator. Can be realized.

  In the fifteenth aspect of the invention, when the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the air below the heat exchanger (37) in the air passage (31) Note that the fan belt (29) is broken or not based on the temperature change of the air below the heat exchanger (37) in the air passage (31). Determined. Even if the determination condition based on the change of the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is not satisfied, the temperature change of the air below the heat exchanger (37) in the air passage (31) If the condition is satisfied, it is determined that the fan belt (29) is broken. Therefore, it can be reliably detected that the fan belt (29) is broken.

  In the sixteenth aspect of the invention, when the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as a radiator, the air above the heat exchanger (37) in the air passage (31). Note that the fan belt (29) is broken or not based on the temperature change of the air above the heat exchanger (37) in the air passage (31). Determined. Even if the determination condition based on the change in the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is not satisfied, the temperature change of the air above the heat exchanger (37) in the air passage (31) If the condition is satisfied, it is determined that the fan belt (29) is broken. Therefore, it can be reliably detected that the fan belt (29) is broken.

  In the seventeenth aspect of the invention, paying attention to the fact that the humidity of the air passage (31) increases when the blower fan (14) stops during the operation of the humidifier (19), the humidity of the air passage (31) Whether or not the fan belt (29) is broken is determined based on the rate of increase per unit time. Even before performing the operation of determining whether the determination condition is satisfied, if the humidity change rate of the air passage (31) satisfies a predetermined condition, it is determined that the fan belt (29) is broken. Is done. Therefore, it is possible to quickly detect that the fan belt (29) is broken during the operation of the humidifier (19).

  In the eighteenth aspect, it is determined whether or not to perform an operation for determining whether or not the determination condition is satisfied based on the rate of change of the current value of the motor current. When the change rate of the current value of the motor current does not satisfy the predetermined condition, the above operation is not executed. Therefore, the above operation can be appropriately executed.

  In the nineteenth aspect, it is determined whether or not to perform an operation for determining whether or not the determination condition is satisfied based on the rate of change in the rotational speed of the blower fan (14). When the change rate of the rotational speed of the blower fan (14) does not satisfy the predetermined condition, the above operation is not executed. Therefore, the above operation can be appropriately executed.

It is a schematic block diagram of the air conditioning apparatus which concerns on embodiment. It is a schematic block diagram of the indoor unit which concerns on embodiment. It is a flowchart of determination of the belt shortage concerning an embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the present embodiment is an air conditioner (10) including an outdoor unit (11) and an indoor unit (13). An outdoor circuit (21) is provided in the outdoor unit (11). An indoor circuit (22) is provided in the indoor unit (13). In this air conditioner (10), a refrigerant circuit that performs a vapor compression refrigeration cycle by connecting an outdoor circuit (21) and an indoor circuit (22) with a liquid side connecting pipe (23) and a gas side connecting pipe (24). (20) is configured.

《Outdoor unit configuration》
The outdoor circuit (21) of the outdoor unit (11) is provided with a compressor (30), an outdoor heat exchanger (34), an expansion valve (36), and a four-way switching valve (33). At one end of the outdoor circuit (21), a liquid side shut-off valve (25) to which the liquid side communication pipe (23) is connected is provided. The other end of the outdoor circuit (21) is provided with a gas side shut-off valve (26) to which the gas side communication pipe (24) is connected.

  The compressor (30) is configured as a hermetic and high-pressure dome type compressor. Electric power is supplied to the compressor (30) via an inverter. The capacity of the compressor (30) can be changed by changing the output frequency of the inverter to change the rotation speed of the motor. The discharge side of the compressor (30) is connected to the first port (P1) of the four-way switching valve (33) via the discharge pipe (40). The suction side of the compressor (30) is connected to the third port (P3) of the four-way switching valve (33) via the suction pipe (41).

  The outdoor heat exchanger (34) is configured as a cross fin type fin-and-tube heat exchanger. An outdoor fan (12) is provided in the vicinity of the outdoor heat exchanger (34). A fan motor is directly connected to the rotating shaft of the outdoor fan (12). In the outdoor heat exchanger (34), heat is exchanged between the outdoor air sent by the outdoor fan (12) and the refrigerant flowing through the outdoor heat exchanger (34). One end of the outdoor heat exchanger (34) is connected to the fourth port (P4) of the four-way switching valve (33). The other end of the outdoor heat exchanger (34) is connected to the liquid side shut-off valve (25) via the liquid pipe (42). The liquid pipe (42) is provided with an expansion valve (36) having a variable opening. In addition, the gas side closing valve (26) is connected to the second port (P2) of the four-way switching valve (33).

  The four-way selector valve (33) is in a first state in which the first port (P1) and the second port (P2) communicate with each other and the third port (P3) and the fourth port (P4) communicate with each other (FIG. 1). And a second state (FIG. 1) in which the first port (P1) and the fourth port (P4) communicate with each other and the second port (P2) and the third port (P3) communicate with each other. The state indicated by a broken line) can be switched.

  On the discharge side of the compressor (30) in the outdoor circuit (21), a discharge temperature sensor (47) for measuring the temperature of the refrigerant discharged from the compressor (30) and the refrigerant discharged from the compressor (30) And a discharge pressure sensor (48) for measuring the pressure. Also, on the suction side of the compressor (30), a suction temperature sensor (49) that measures the temperature of the refrigerant sucked into the compressor (30) and the pressure of the refrigerant sucked into the compressor (30) are measured. A suction pressure sensor (50) is provided. The outdoor circuit (21) includes an outdoor gas temperature sensor (43) for measuring the temperature of the refrigerant on the gas side of the outdoor heat exchanger (34), and the temperature of the refrigerant on the liquid side of the outdoor heat exchanger (34). And an outdoor liquid temperature sensor (44) for measuring.

《Composition of indoor unit》
The indoor circuit (22) of the indoor unit (13) is provided with an indoor heat exchanger (37). The indoor heat exchanger (37) is configured as a cross-fin type fin-and-tube heat exchanger. In the vicinity of the indoor heat exchanger (37), an indoor fan (14) composed of a sirocco fan is provided. The indoor fan (14) is configured by a blower fan (14) to which the power of the fan motor (28) is transmitted via the fan belt (29). In the indoor heat exchanger (37), heat is exchanged between the indoor air sent by the indoor fan (14) and the refrigerant flowing through the indoor heat exchanger (37).

  The indoor circuit (22) measures the temperature of the refrigerant on the gas side of the indoor heat exchanger (37) and the temperature of the refrigerant on the liquid side of the indoor heat exchanger (37). An indoor liquid temperature sensor (46) is provided.

  As shown in FIG. 2, the indoor unit (13) includes an indoor unit casing (15) that houses the components. The indoor unit casing (15) has a suction port (16) and a blowout port (17). In the indoor unit casing (15), an air passage (31) through which air flows upward from the suction port (16) toward the blowout port (17) is formed.

  The suction port (16) is formed in the lower part of the side wall of the indoor unit casing (15). A suction duct capable of switching between a state communicating with the room and a state communicating with the room is connected to the suction port (16). The blower outlet (17) is formed in the top plate of the indoor unit casing (15). A blow-out duct connected to a plurality of indoor spaces is connected to the blow-out opening (17).

  In the air passage (31), the indoor heat exchanger (37) is installed obliquely. The indoor heat exchanger (37) is arranged so as to partition the air passage (31) into the suction port (16) side and the blower outlet (17) side. The upper end of the indoor heat exchanger (37) is located near the front surface of the indoor unit casing (15) where the suction port (16) is formed. On the other hand, the lower end of the indoor heat exchanger (37) is located near the back surface of the indoor unit casing (15).

  In the air passage (31), the indoor fan (14) is disposed above the indoor heat exchanger (37). The blower outlet of the indoor fan (14) is connected to the blower outlet (17) of the indoor unit casing (15). A fan motor (28) is disposed obliquely below the indoor fan (14). A rubber fan belt (29) is wound around the motor-side pulley connected to the rotating shaft of the fan motor (28) and the fan-side pulley connected to the rotating shaft of the indoor fan (14). The fan belt (29) transmits the power of the fan motor (28) to the indoor fan (14). The air passage (31) is provided with a humidifier (19) for imparting moisture to the air that has passed through the indoor heat exchanger (37).

  Also, in the indoor unit casing (15), the intake air temperature sensor (51) that measures the temperature of air sucked from the suction port (16) and the humidity of the air sucked from the suction port (16) are measured. An intake air humidity sensor (52) that performs the above operation and a blown air temperature sensor (53) that measures the temperature of the air blown from the indoor fan (14) are provided.

  An electrical component unit (27) is installed on the bottom plate of the indoor unit casing (15). The electrical component unit (27) is provided with a power supply circuit for supplying power from the AC power source to the fan motor (28). A current detector for measuring the current value of the motor current flowing through the fan motor (28) is connected to the power supply circuit. The power supply circuit is connected to an overcurrent protection unit that stops the supply of power to the fan motor (28) when an overcurrent flows through the fan motor (28). For example, the overcurrent protection unit cuts off the motor current when the state in which the motor current exceeds a predetermined threshold continues for a predetermined time.

-Operation of refrigeration equipment-
Next, the operation of the air conditioner (10) will be described. In the air conditioner (10), the cooling operation and the heating operation are switched by the four-way switching valve (33). During the cooling operation and the heating operation, the suction duct is set in a state of communicating with the room.

  Further, the air conditioner (10) can perform a ventilation operation for driving the indoor fan (14) without executing the refrigeration cycle. During the ventilation operation, the suction duct is set to communicate with the outside of the room. Below, the flow of the refrigerant | coolant in air_conditionaing | cooling operation and heating operation is demonstrated.

<Cooling operation>
In the cooling operation, the four-way switching valve (33) is set to the second state. When the compressor (30) is operated in this state, the refrigerant circuit (20) performs a refrigeration cycle in which the outdoor heat exchanger (34) serves as a condenser and the indoor heat exchanger (37) serves as an evaporator. . This refrigeration cycle corresponds to the evaporation side refrigeration cycle. In the cooling operation, the opening degree of the expansion valve (36) is appropriately adjusted.

  Specifically, the refrigerant discharged from the compressor (30) is condensed by exchanging heat with outdoor air in the outdoor heat exchanger (34). The refrigerant condensed in the outdoor heat exchanger (34) is depressurized when passing through the expansion valve (36), and then is evaporated by exchanging heat with indoor air in the indoor heat exchanger (37). The refrigerant evaporated in the indoor heat exchanger (37) is sucked into the compressor (30) and compressed.

<Heating operation>
In the heating operation, the four-way switching valve (33) is set to the first state. When the compressor (30) is operated in this state, the refrigerant circuit (20) performs a refrigeration cycle in which the outdoor heat exchanger (34) serves as an evaporator and the indoor heat exchanger (37) serves as a condenser. . This refrigeration cycle corresponds to the refrigeration cycle on the heat radiation side. In the heating operation, the opening degree of the expansion valve (36) is appropriately adjusted.

  Specifically, the refrigerant discharged from the compressor (30) is condensed by exchanging heat with indoor air in the indoor heat exchanger (37). The refrigerant condensed in the indoor heat exchanger (37) is decompressed when passing through the expansion valve (36), and thereafter evaporates by exchanging heat with outdoor air in the outdoor heat exchanger (34). The refrigerant evaporated in the outdoor heat exchanger (34) is sucked into the compressor (30) and compressed.

"controller"
The air conditioner (10) includes a controller (35) that controls the operation of the air conditioner (10) based on a set temperature or the like input by a user. The controller (35) includes an operation control unit (54) constituting operation control means (54) for controlling the operation of the refrigerant circuit (20) and the operation of the fans (12, 14), and the fan belt (29) is broken. An abnormality determination unit (55) that constitutes an abnormality determination means (55) for determining whether or not the fan belt (29) is broken by the abnormality determination unit (55) And an abnormal alarm unit (56) for outputting a belt out alarm.

  The operation control unit (54) is configured to control the operation capacity of the compressor (30). In the operation control unit (54), the target evaporation temperature is set as the target value of the refrigerant evaporation temperature Te in the indoor heat exchanger (37) during the cooling operation. The initial value of the target evaporation temperature is set to 5 ° C., for example. The target evaporation temperature may vary depending on operating conditions, but is always set to a temperature higher than a predetermined lower limit temperature (for example, 0 ° C.). The operation control unit (54) during the cooling operation calculates the saturation temperature corresponding to the measured pressure of the suction pressure sensor (50) as the evaporation temperature Te, and the compressor so that the calculated evaporation temperature Te becomes the target evaporation temperature. Control the operating capacity of (30). During the cooling operation, the saturation pressure corresponding to the lower limit temperature becomes the lower limit pressure. During the cooling operation, the range in which the refrigerant evaporation temperature in the indoor heat exchanger (37) is higher than the lower limit temperature (the range in which the pressure of the low-pressure refrigerant sucked into the compressor (30) is higher than the lower limit pressure), The operating capacity of the compressor (30) is adjusted as a normal range that can be in a state where the blower fan (14) is driven by the fan motor (28) during the refrigeration cycle.

  In the operation control unit (54), the target condensing temperature is set as the target value of the refrigerant condensing temperature Tc in the indoor heat exchanger (37) during the heating operation. The initial value of the target condensation temperature is set to 45 ° C., for example. The target condensing temperature may vary depending on operating conditions, but is always set to a temperature lower than a predetermined upper limit temperature (for example, 50 ° C.). The operation control unit (54) during the heating operation calculates the saturation temperature corresponding to the measurement pressure of the discharge pressure sensor (48) as the condensation temperature Tc, and the compressor so that the calculated condensation temperature Tc becomes the target condensation temperature. Control the operating capacity of (30). During the heating operation, the saturation pressure corresponding to the upper limit temperature becomes the upper limit pressure. During heating operation, the range in which the condensation temperature of the refrigerant in the indoor heat exchanger (37) is lower than the upper limit temperature (the range in which the pressure of the high-pressure refrigerant discharged from the compressor (30) is lower than the upper limit pressure), The operating capacity of the compressor (30) is adjusted as a normal range.

  In addition, the operation control unit (54) forces the operating capacity of the compressor (30) when the measured pressure of the suction pressure sensor (50) is equal to or lower than a predetermined droop determination low pressure during cooling operation. Perform the low-pressure side drooping operation to lower. In addition, the operation control unit (54) forces the operating capacity of the compressor (30) when the measured pressure of the discharge pressure sensor (48) is equal to or higher than a predetermined droop determination high pressure during heating operation. Perform the high-pressure side drooping action to lower.

  The operation control unit (54) is configured to adjust the opening degree of the expansion valve (36). In the operation control unit (54), a target superheat degree (for example, 5 ° C.) is set as a target value of the superheat degree of the refrigerant flowing out of the evaporator. During cooling operation, the operation control unit (54) performs indoor heat exchange by subtracting the saturation temperature (evaporation temperature) corresponding to the measured pressure of the suction pressure sensor (50) from the measured temperature of the indoor gas temperature sensor (45). The degree of superheat of the refrigerant flowing out of the vessel (37) is calculated, and the opening degree of the expansion valve (36) is adjusted so that the calculated degree of superheat becomes the target degree of superheat. In addition, the operation control unit (54) during heating operation calculates a value obtained by subtracting a saturation temperature (evaporation temperature) corresponding to the measured pressure of the suction pressure sensor (50) from the measured temperature of the outdoor gas temperature sensor (43). The degree of superheat of the refrigerant flowing out from the heat exchanger (34) is calculated, and the opening degree of the expansion valve (36) is adjusted so that the calculated degree of superheat becomes the target degree of superheat.

  The abnormality determination unit (55) is configured to determine whether the belt has run out or not while determining whether the fan belt (29) is broken during the operation of the air conditioner (10). The determination of running out of the belt includes a fan stop confirmation operation, a suction humidity confirmation operation, and a main determination operation. Hereinafter, the determination of the belt running out will be described with reference to the flowchart shown in FIG.

In the determination of the belt out, step ST1 is first performed. In step ST1, the abnormality determination unit (55) performs an operation of determining whether or not the first condition is satisfied as the fan stop confirmation operation. The first condition is satisfied when at least one of the following Expression 1 and Expression 2 is satisfied. When the first condition is satisfied, the abnormality determination unit (55) determines that the fan motor (28) is rotating, and the process proceeds to step ST2. If the first condition is not satisfied, step ST1 is performed again. The fan motor rotation state is a state where the motor current is not interrupted by the overcurrent protection unit. Step ST2 and subsequent steps are performed when the fan motor is rotating.
Formula 1: Motor current decrease rate A <current reference value A1
Formula 2: Decrease rate N of fan rotation speed <reference speed N1 of rotation speed

  In the above formula 1, the motor current decrease rate A is the rate of decrease of the current value of the motor current supplied to the fan motor (28) per unit time. The abnormality determination unit (55) detects the rate of decrease of the motor current per unit time (for example, per second) detected by the current detection unit as the rate of decrease A of the motor current. The current reference value A1 is a determination threshold value set in advance in the abnormality determination unit (55).

  In Formula 2, the fan rotation speed decrease rate N is a decrease rate per unit time of the rotation speed of the indoor fan (14). The abnormality determination unit (55) uses the rate of decrease per unit time (for example, per second) of the detection speed of the rotation speed sensor provided on the rotation shaft of the indoor fan (14) as the decrease rate N of the fan rotation speed. To detect. The rotation speed reference value N1 is a determination threshold preset in the abnormality determination unit (55).

In step ST2, the abnormality determining unit (55) performs an operation of determining whether or not the second condition is satisfied as the suction humidity confirmation operation. The second condition is satisfied when a state in which the following Expression 3 is satisfied continues for a predetermined time t1 (for example, t1 = 5 minutes) during operation of the humidifier (19). If the second condition is satisfied, the abnormality determination unit (55) determines that the fan belt (29) is broken, and proceeds to step ST9. If the second condition is not satisfied, the process proceeds to step ST3.
Formula 3: Increase rate of suction humidity Hus> humidity reference value Hus1

  In the above formula 3, the increase rate Hus of the suction humidity is the increase rate per unit time (for example, per minute) of the measured humidity of the suction air humidity sensor (52). The measured humidity of the intake air humidity sensor (52) reflects the humidity of the air passage (31). The humidity reference value Hus1 is a determination threshold value (for example, 5% / min) preset in the abnormality determination unit (55).

  The abnormality determination unit (55) of the present embodiment has a predetermined time during which the rate of increase Hus per unit time of humidity in the air passage (31) is greater than the humidity reference value Hus1 in the fan motor rotating state. In the case of reaching, it is determined that the fan belt (29) is broken without performing a main determination operation described later.

  Step ST3 to step ST8 are main determination operations. In step ST3, the abnormality determination unit (55) confirms the operating state of the air conditioner (10), and determines to which step ST the process proceeds next. When the operation state of the air conditioner (10) is the cooling thermo-on state in which the compressor (30) is being operated during the cooling operation, the process proceeds to step ST4. Moreover, when the operation state of the air conditioner (10) is the heating thermo-on state in which the compressor (30) is being operated during the heating operation, the process proceeds to step ST6. If the operating state of the air conditioner (10) is neither the cooling thermo-on state nor the heating thermo-on state, the process proceeds to step ST8.

In step ST4, the abnormality determination unit (55) performs an operation of determining whether or not the third condition is satisfied. The third condition is that the condition in which the following Expression 4 is satisfied continues for a predetermined time t2 (for example, t2 = 5 minutes), and that the operation control unit (54) is in the low-pressure side drooping operation. This is established when at least one of the 3-2 condition and the 3rd-3 condition that the state in which the following Expression 5 is satisfied continues for a predetermined time t3 (for example, t3 = 5 minutes) is satisfied. If the third condition is satisfied, the abnormality determining unit (55) determines that the fan belt (29) is broken, and proceeds to step ST9. If the third condition is not satisfied, the process proceeds to step ST5.
Formula 4: Low pressure LP <first low pressure reference value LP1
Formula 5: Blowing temperature Tf + predetermined value> suction temperature Ts

  In the above equation 4, the low pressure LP is a measured pressure (measurement value for determination) of the suction pressure sensor (50). The suction pressure sensor (50) constitutes measuring means (46, 48, 50) that measures a physical quantity representing the state of the refrigerant flowing through the indoor heat exchanger (37) as a measurement value for determination. The first low-pressure reference value LP1 is a determination threshold (for example, 0.2 MPa) preset in the abnormality determination unit (55). The first low pressure reference value LP1 is set to a value lower than the lower limit pressure and higher than the drooping determination low pressure. The 3-1 condition is one of the determination conditions that the physical quantity representing the state of the refrigerant flowing through the indoor heat exchanger (37) is out of the normal range for a predetermined time or more. The third condition is that the pressure LP of the low-pressure refrigerant sucked into the compressor (30) is less than the first low-pressure side reference value LP1 lower than the lower limit pressure over a predetermined time. 1 constitutes a low pressure condition.

In the third condition, it may be determined whether or not the fan belt (29) is broken based on a change in the evaporation temperature Te. Specifically, in the third condition, instead of the 3-1 condition, the 3-4 condition that the duration of the state in which the following Expression 6 is satisfied is a predetermined time (for example, 5 minutes) or more is used. .
Formula 6: Evaporation temperature Te <first low temperature reference value Te1

  In the above equation 6, the evaporation temperature Te is a measured temperature (measurement value for determination) of the indoor liquid temperature sensor (46). The indoor liquid temperature sensor (46) constitutes measuring means (46, 48, 50). The first low temperature reference value Te1 is a determination threshold set in advance in the abnormality determination unit (55), and is set to a value lower than the lower limit temperature. The third 3-4 condition is one of the above determination conditions, and the first low temperature side reference value in which the refrigerant evaporation temperature Te in the indoor heat exchanger (37) is lower than the lower limit temperature over a predetermined time. The first low-temperature condition is set to be less than Te1.

  Further, the 3-1 condition based on the low pressure LP and the 3-4 condition based on the evaporation temperature Te may be used in combination. In this case, the abnormality determining unit (55) determines that the fan belt (29) is broken when at least one of the 3-1 condition and the 3-4 condition is satisfied.

  Moreover, in the said Formula 5, suction temperature Ts is the measurement temperature of a suction air temperature sensor (51). The blowing temperature Tf is a temperature measured by the blowing air temperature sensor (53). In this embodiment, the value which added predetermined value (for example, 3 degreeC) to the blowing temperature Tf comprises the low temperature air reference value. The abnormality determination unit (55) of the present embodiment is not limited to the case where the 3-1 condition (the 3-4 condition) that constitutes the determination condition is satisfied, but also the room in the air passage (31) in the fan motor rotation state. Even when the condition that the duration of the state where the temperature Ts of the air below the heat exchanger (37) is lower than the low-temperature air reference value (Tf + predetermined value) reaches a predetermined time is satisfied, the fan belt (29 ) Is determined to be broken.

  In addition, instead of the 3-3 condition, the 3-5 condition that the duration of the state where the suction temperature Ts is lower than the predetermined suction determination temperature Ts1 is a predetermined time (for example, 5 minutes) or more is used. Also good. In this case, the suction determination temperature Ts1 constitutes a low-temperature air reference value and is set based on the target evaporation temperature. The suction determination temperature Ts1 is set to a temperature that is lower than the target evaporation temperature by a predetermined value, for example. Further, in addition to the third to fifth conditions, the third to sixth conditions that the duration of the state where the blowing temperature Tf is higher than the predetermined blowing determination temperature Tf1 is a predetermined time (for example, 5 minutes) or more are used. Also good. In this case, the abnormality determining unit (55) determines that the fan belt (29) is broken when at least one of the third to fifth conditions and the third to sixth conditions is satisfied.

In step ST5, the abnormality determining unit (55) performs an operation of determining whether or not the fourth condition is satisfied. The fourth condition is that the 4-1 condition that the operating capacity of the compressor (30) is in a low capacity range set in a controllable range and the condition in which the following Expression 7 is satisfied. The condition is satisfied when the 4-2 condition of continuing for a predetermined time t4 (for example, t4 = 5 minutes) is satisfied. When the fourth condition is satisfied, the abnormality determining unit (55) determines that the fan belt (29) is broken, and proceeds to step ST9. If the fourth condition is not satisfied, the process proceeds to step ST8.
Expression 7: Low pressure LP <second low pressure reference value LP2

  In Expression 7, the second low-pressure reference value LP2 is a determination threshold (for example, 0.57 MPa) preset in the abnormality determination unit (55). The second low pressure reference value LP2 is a refrigerant pressure at which the saturation temperature becomes, for example, −5 ° C., and is set to a value lower than the lower limit pressure and higher than the first low pressure reference value LP1. The 4-2 condition constitutes the determination condition. The fourth condition is that the pressure LP of the low-pressure refrigerant sucked into the compressor (30) is lower than the lower limit pressure and lower than the first low pressure for a predetermined time or more in the fan motor rotating state and in the low capacity state. The second low-pressure condition is configured to be lower than the second low-pressure side reference value LP2 higher than the side reference value LP1.

In the fourth condition, it may be determined whether or not the fan belt (29) is broken based on the change in the evaporation temperature Te. Specifically, in the fourth condition, instead of the 4-2 condition, a 4-3 condition that the duration of the state in which the following Expression 8 is satisfied is a predetermined time (for example, 5 minutes) or more is used.
Formula 8: Evaporation temperature Te <second low temperature reference value Te2

  In the above equation 8, the second low temperature reference value Te2 is a determination threshold (for example, −5 ° C.) preset in the abnormality determination unit (55). The second low temperature reference value Te2 is set to a value lower than the lower limit temperature and higher than the first low temperature reference value Te1. In this case, the 4th-3 condition constitutes a determination condition. The fourth condition is that the fan motor is in a rotating state and in a low capacity state, and the evaporation temperature Te of the refrigerant in the indoor heat exchanger (37) is lower than the lower limit temperature and lower than the first low temperature side over a predetermined time. The second low temperature condition is configured to be lower than the second low temperature side reference value Te2 higher than the reference value Te1. As in the case of the third condition, the 4-2 condition based on the low pressure LP and the 4-3 condition based on the evaporation temperature Te may be used in combination.

In step ST6, the abnormality determination unit (55) performs an operation of determining whether or not the fifth condition is satisfied. The fifth condition is that the condition in which the following Expression 9 is satisfied continues for a predetermined time t5 (for example, t5 = 5 minutes), and that the operation control unit (54) is in the high-pressure side drooping operation. It is satisfied when at least one of the 5-2 conditions is satisfied. If the fifth condition is satisfied, the abnormality determination unit (55) determines that the fan belt (29) is broken, and proceeds to step ST9. If the fifth condition is not satisfied, the process proceeds to step ST7.
Formula 9: High pressure HP> First high pressure reference value HP1

  In the above formula 9, the high pressure HP is the measurement pressure (measurement value for determination) of the discharge pressure sensor (48). The discharge pressure sensor (48) constitutes measuring means (46, 48, 50). The first high-pressure reference value HP1 is a determination threshold (for example, 3.5 MPa) preset in the abnormality determination unit (55). The first high pressure reference value HP1 is set to a value higher than the upper limit pressure and lower than the droop determination high pressure. The 5-1 condition is one of the determination conditions, and the first high-pressure side reference value in which the pressure HP of the high-pressure refrigerant discharged from the compressor (30) is higher than the upper limit pressure over a predetermined time. The first high pressure condition of exceeding HP1 is configured.

In the fifth condition, it may be determined whether or not the fan belt (29) is broken based on a change in the condensation temperature Tc. Specifically, in the fifth condition, instead of the 5-1 condition, the 5-3 condition that the duration of the state in which the following Expression 10 is satisfied is equal to or longer than a predetermined time (for example, 5 minutes) is used.
Expression 10: Condensation temperature Tc> first high temperature reference value Tc1

  In the above formula 10, the condensation temperature Tc is the measured temperature (measurement value for determination) of the indoor liquid temperature sensor (46). Moreover, 1st high temperature reference value Tc1 is the determination threshold value preset by the abnormality determination part (55). The first high temperature reference value Tc1 is set to a value higher than the upper limit temperature. The 5th-3 condition is one of the determination conditions, and the first high temperature side reference value Tc1 in which the refrigerant condensing temperature Tc in the indoor heat exchanger (37) is higher than the upper limit temperature for a predetermined time or more. The first high temperature condition of exceeding is configured.

  Further, the 5-1 condition based on the high pressure HP and the 5-3 condition based on the condensation temperature Tc may be used in combination. In this case, the abnormality determining unit (55) determines that the fan belt (29) is broken when at least one of the 5-1 condition and the 5-3 condition is satisfied.

In step ST7, the abnormality determining unit (55) performs an operation of determining whether or not the sixth condition is satisfied. The sixth condition is that the operating condition of the compressor (30) is set in the low capacity region and that the following equation 11 is satisfied is a predetermined time t6 (for example, t6 = 5 minutes). It is satisfied when at least one of the 6-2 conditions to continue is satisfied. If the sixth condition is satisfied, the abnormality determining unit (55) determines that the fan belt (29) is broken and proceeds to step ST9. If the sixth condition is not satisfied, the process proceeds to step ST8.
Formula 11: High pressure HP> Second high pressure reference value HP2

  In the above formula 11, the second high-pressure reference value HP2 is a determination threshold value (for example, 3.0 MPa) preset in the abnormality determination unit (55). The second high pressure reference value HP2 is a refrigerant pressure at which the saturation temperature becomes 50 ° C., for example, and is set to a value that is equal to or higher than the upper limit pressure and lower than the first high pressure reference value HP1. The 6-2 condition constitutes a determination condition. The sixth condition is that the pressure HP of the high-pressure refrigerant discharged from the compressor (30) is not less than the upper limit pressure and not less than the upper limit pressure for a predetermined time or more in the fan motor rotating state and in the low capacity state. The second high pressure condition is configured to be less than the second high pressure side reference value HP2 lower than the side reference value HP1.

In the sixth condition, it may be determined whether or not the fan belt (29) is broken based on a change in the condensation temperature Tc. Specifically, in the sixth condition, instead of the 6-2 condition, a 6-3 condition is used in which the duration of the state in which the following Expression 12 is satisfied is a predetermined time (for example, 5 minutes) or more.
Formula 12: Condensation temperature Tc> second high temperature reference value Tc2

  In the above formula 12, the second high temperature reference value Tc2 is a determination threshold value preset in the abnormality determination unit (55). The second high temperature reference value Tc2 is set to a value equal to or higher than the upper limit temperature and lower than the first high temperature reference value Tc1. In this case, the 6th-3 condition constitutes a determination condition. The sixth condition is that the fan motor is in a rotating state and in a low capacity state, and the refrigerant condensation temperature Tc in the indoor heat exchanger (37) is equal to or higher than the upper limit temperature for the predetermined time or longer and the first high temperature side. A second high temperature condition is set such that the second high temperature side reference value Tc2 that is lower than the reference value Tc1 is exceeded. As in the case of the fifth condition, the 6-2 condition based on the high pressure HP and the 6-3 condition based on the condensation temperature Tc may be used in combination.

In Step ST7, the abnormality determination unit (55) performs an operation of determining whether or not the seventh condition is satisfied in addition to the operation of determining whether or not the sixth condition is satisfied. The seventh condition is satisfied when the following expression 13 is satisfied for a predetermined time t7 (for example, t7 = 5 minutes).
Formula 13: Blowing temperature Tf> Heating determination temperature Tf2

  In the above equation 13, the heating determination temperature Tf2 is a determination threshold preset in the abnormality determination unit (55), and constitutes a high-temperature air reference value. The heating determination temperature Tf2 is set based on the target condensation temperature during the heating operation. The heating determination temperature Tf2 is set, for example, to a temperature that is higher than the target condensation temperature by a predetermined value.

  The abnormality determination unit (55) of the present embodiment is not limited to the case where the second high-pressure condition is satisfied, and the air temperature Tf above the indoor heat exchanger (37) in the air passage (31) in the fan motor rotation state. It is determined that the fan belt (29) is broken also when the condition that the duration of the state in which the temperature becomes higher than the heating determination temperature Tf2 reaches a predetermined time is satisfied.

  In step ST8, the abnormality determination unit (55) checks whether or not the operation state of the air conditioner (10) is set to the ventilation operation. If the abnormality determining unit (55) is set to the ventilation operation, the process proceeds to step ST9. If it is not set to the ventilation operation, the process proceeds to step ST1. The abnormality determination unit (55) during the ventilation operation determines that the fan belt (29) is broken if the first condition is satisfied in the fan stop confirmation operation.

  In step ST9, the abnormal alarm unit (56) outputs a belt out alarm indicating that the fan belt is out. The belt out alarm is output to a remote controller or the like. In step ST9, the abnormality determination unit (55) outputs a belt breakage detection signal to the abnormality notification unit (56). Then, when receiving the belt breakage detection signal, the abnormality reporting unit (56) outputs a belt breakage alarm to the remote controller or the like.

-Effect of the embodiment-
In this embodiment, when the indoor fan (14) stops, the physical quantity of the refrigerant in the indoor heat exchanger (37) is out of the normal range. When the physical quantity representing the state is out of the normal range for a predetermined time or more, the abnormality determination unit (55) determines that the fan belt (29) is broken. Therefore, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized.

  In this embodiment, when the operation capacity of the compressor (30) is adjusted so that the pressure of the low-pressure refrigerant does not become a predetermined lower limit pressure or less during the cooling operation, the indoor fan (14) is turned on during the cooling operation. Whether or not it is stopped can be determined by whether or not the pressure of the low-pressure refrigerant is equal to or lower than the lower limit pressure (or the evaporation temperature of the refrigerant in the indoor heat exchanger (37) is equal to or lower than the lower limit temperature), It is determined whether or not the fan belt (29) is broken. For this reason, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized as the air conditioner (10) performing the cooling operation.

  Further, in this embodiment, when the operating capacity of the compressor (30) is not immediately reduced to the low capacity region after the fan belt (29) is broken, it is quickly detected that the fan belt (29) is broken. The conditions that can be detected and the conditions that can quickly detect that the fan belt (29) is broken in response to a decrease in the pressure of the low-pressure refrigerant (or a decrease in the evaporation temperature) are used to determine whether the belt has run out. . For this reason, even if the operating capacity of the compressor (30) immediately decreases to the low capacity area after the fan belt (29) breaks, it does not immediately decrease to the low capacity area. It is possible to quickly detect that the fan belt (29) is broken.

  In the present embodiment, when the operating capacity of the compressor (30) is adjusted so that the pressure of the high-pressure refrigerant does not exceed a predetermined upper limit pressure during the heating operation, the indoor fan (14) is turned on during the heating operation. Utilizing that it can be determined whether or not the pressure of the high-pressure refrigerant is equal to or higher than the upper limit pressure (or whether the refrigerant condensing temperature in the indoor heat exchanger (37) is equal to or higher than the upper limit temperature). It is determined whether or not the fan belt (29) is broken. For this reason, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized as the air conditioner (10) that performs the heating operation.

  Further, in this embodiment, when the operating capacity of the compressor (30) is not immediately reduced to the low capacity region after the fan belt (29) is broken, it is quickly detected that the fan belt (29) is broken. The conditions that can be detected and the conditions that can quickly detect that the fan belt (29) is broken with respect to the increase in the pressure of the high-pressure refrigerant (or the increase in the condensation temperature) are used to determine whether the belt has run out. . For this reason, even if the operating capacity of the compressor (30) immediately decreases to the low capacity area after the fan belt (29) breaks, it does not immediately decrease to the low capacity area. It is possible to quickly detect that the fan belt (29) is broken.

  In the present embodiment, when the indoor fan (14) is stopped, the physical quantity representing the state of the refrigerant flowing through the indoor heat exchanger (37) is outside the normal range, and the operating capacity of the compressor (30) is reduced. Therefore, the duration of the state in which the physical quantity representing the state of the refrigerant flowing through the indoor heat exchanger (37) is outside the normal range in a state where the abnormality determination unit (55) is in the fan motor rotating state and in the low capacity state is a predetermined time. Is reached, it is determined that the fan belt (29) is broken. Therefore, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized.

  In this embodiment, when the operation capacity of the compressor (30) is adjusted so that the pressure of the low-pressure refrigerant does not become a predetermined lower limit pressure or less during the cooling operation, the indoor fan (14) is turned on during the cooling operation. The fan belt (29) breaks using the fact that whether or not it is stopped can be judged from the pressure of the low-pressure refrigerant (or the evaporation temperature correlated with the pressure of the low-pressure refrigerant) and the operating capacity of the compressor (30). It is determined whether or not. For this reason, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized as the air conditioner (10) performing the cooling operation.

  In the present embodiment, when the operating capacity of the compressor (30) is adjusted so that the pressure of the high-pressure refrigerant does not exceed a predetermined upper limit pressure during the heating operation, the indoor fan (14) is turned on during the heating operation. The fan belt (29) is broken by using the fact that whether or not it is stopped can be judged from the pressure of the high-pressure refrigerant (or the condensing temperature correlated with the pressure of the high-pressure refrigerant) and the operating capacity of the compressor (30). It is determined whether or not. For this reason, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized as the air conditioner (10) that performs the heating operation.

  Further, in this embodiment, when the indoor fan (14) stops during the cooling operation, the temperature of the air below the indoor heat exchanger (37) in the air passage (31) is relatively greatly reduced. Based on the temperature change of the air below the indoor heat exchanger (37) in the air passage (31), it is determined whether or not the fan belt (29) is broken. Even if the determination condition based on the change of the physical quantity of the refrigerant in the indoor heat exchanger (37) is not satisfied, the temperature change of the air below the indoor heat exchanger (37) in the air passage (31) satisfies the predetermined condition. If it is satisfied, it is determined that the fan belt (29) is broken. Therefore, it can be reliably detected that the fan belt (29) is broken.

  Further, in the present embodiment, focusing on the fact that the temperature of the air above the indoor heat exchanger (37) in the air passage (31) rises relatively large when the indoor fan (14) stops during the heating operation. Based on the temperature change of the air above the indoor heat exchanger (37) in the air passage (31), it is determined whether or not the fan belt (29) is broken. Even if the determination condition based on the change in the physical quantity of the refrigerant in the indoor heat exchanger (37) is not satisfied, the temperature change of the air above the indoor heat exchanger (37) in the air passage (31) satisfies the predetermined condition. If it is satisfied, it is determined that the fan belt (29) is broken. Therefore, it can be reliably detected that the fan belt (29) is broken.

  In this embodiment, focusing on the fact that the humidity of the air passage (31) increases when the indoor fan (14) stops during operation of the humidifier (19), the unit of humidity of the air passage (31) Based on the rate of increase per hour, it is determined whether or not the fan belt (29) is broken. Even before performing the operation of determining whether the determination condition is satisfied, if the humidity change rate of the air passage (31) satisfies a predetermined condition, it is determined that the fan belt (29) is broken. Is done. Therefore, it is possible to quickly detect that the fan belt (29) is broken during the operation of the humidifier (19).

  Further, in the present embodiment, it is determined whether or not to perform an operation for determining whether or not the determination condition is satisfied based on the rate of change of the current value of the motor current. When the change rate of the current value of the motor current does not satisfy the predetermined condition, the above operation is not executed. Therefore, the above operation can be appropriately executed.

  Further, in the present embodiment, it is determined whether or not to perform an operation for determining whether or not the determination condition is satisfied based on the rate of change in the rotational speed of the indoor fan (14). When the rate of change of the rotational speed of the indoor fan (14) does not satisfy a predetermined condition, the above operation is not executed. Therefore, the above operation can be appropriately executed.

<< Other Embodiments >>
About the said embodiment, it is good also as the following structures.

  About the said embodiment, the abnormality determination part (55) may be comprised so that only one of step ST4 and step ST5 may be performed as a determination of belt out in a cooling thermostat state.

  Moreover, about the said embodiment, the abnormality determination part (55) may be comprised so that only one of step ST6 and step ST7 may be performed as determination of the belt running out in a heating thermo state.

  In the above embodiment, the refrigerant circuit (20) may be configured to perform a supercritical cycle in which the high pressure of the refrigeration cycle is set to a value higher than the critical pressure of the refrigerant. In this case, in a normal refrigeration cycle in which the high pressure of the refrigeration cycle is set to a value lower than the critical pressure of the refrigerant, a heat exchanger that serves as a condenser operates as a gas cooler. For example, carbon dioxide is used as the refrigerant. In this case, the abnormality determination unit (55) during the heating operation uses the temperature of the refrigerant at a fixed position such as the inlet of the indoor heat exchanger (37) as a measurement value for determination instead of the condensation temperature, and determines the fan belt (29 ) Is broken or not.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for an air conditioner including a blower fan in which power of a fan motor is transmitted via a fan belt.

10 Air Conditioner 14 Indoor Fan (Blower Fan)
20 Refrigerant circuit 28 Fan motor 29 Fan belt 30 Compressor 35 Controller 37 Indoor heat exchanger (heat exchanger)
54 Operation control unit (operation control means)
55 Abnormality determination unit (abnormality determination means)
56 Abnormal Report Section

  The present invention relates to an air conditioner including a blower fan in which power of a fan motor is transmitted via a fan belt.

  Conventionally, an air conditioner including a blower fan in which power of a fan motor is transmitted via a fan belt is known. This type of air conditioner is disclosed in Patent Document 1, for example.

  In the air conditioner of Patent Literature 1, an upstream chamber in which a hot water coil and a cold water coil are installed and a downstream chamber in which a blower fan and a duct are installed are formed in an air conditioner casing. A fan driving motor is linked to the blower fan via a fan belt.

JP-A-6-323564

  By the way, in this type of air conditioner, the fan belt may break due to a decrease in the strength of the fan belt due to deterioration. However, the conventional air conditioner cannot detect that the fan belt is broken even if the fan belt is broken.

  The present invention has been made in view of such points, and an object of the present invention is to break the fan belt in an air conditioner including a blower fan to which the power of the fan motor is transmitted via the fan belt. Is configured to be detectable.

According to a first aspect of the present invention, a compressor (30) having a variable operating capacity and a heat exchanger (37) are provided, and a refrigerant circuit (20) for circulating a refrigerant to perform a refrigeration cycle, and the heat exchanger ( 37) A blower fan (14) for sending air to the fan, a fan motor (28) for driving the blower fan (14), and a fan for transmitting the power of the fan motor (28) to the blower fan (14) The target is an air conditioner (10) provided with a belt (29). The air conditioner (10) includes a measuring unit (46, 48, 50) for measuring a physical quantity representing a state of the refrigerant flowing through the heat exchanger (37) as a measurement value for determination, and the refrigeration cycle. The operating capacity of the compressor (30) is adjusted so that the determination measurement value is within a predetermined normal range, and when the determination measurement value is out of the normal range, the compressor (30) An operation control means (54) for reducing the operation capacity, a fan motor rotating state in which the fan motor (28) is rotating during the refrigeration cycle, and a range in which the operation capacity of the compressor (30) can be controlled. An abnormality determining means (55) for determining that the fan belt (29) is broken when a predetermined determination condition is satisfied in a low capacity state set in a low capacity region, The measurement value for judgment is in the normal range over a predetermined time. It is a condition that is out et al.

In 1st invention, a measurement means (46,48,50) measures the physical quantity showing the state of the refrigerant | coolant which flows through the heat exchanger (37) to which air is sent by the ventilation fan (14) as a measurement value for determination. When the abnormality determination means (55) is in the fan motor rotating state and in the low capacity state, and the determination condition that the determination measurement value is out of the normal range for a predetermined time or more is satisfied, the fan belt It is determined that (29) is broken. Here, for example, in the case where the heat exchanger (37) to which the air of the blower fan (14) is supplied is an air conditioner (10) operating as an evaporator, the refrigerant flowing through the heat exchanger (37) Among the physical quantities representing this state, for example, the operating capacity of the compressor (30) is adjusted such that the pressure of the low-pressure refrigerant sucked into the compressor (30) is higher than a predetermined lower limit pressure. That is, the range in which the pressure of the low-pressure refrigerant is higher than the lower limit pressure corresponds to the normal range. In such an air conditioner (10), when the blower fan (14) stops during the refrigeration cycle, the amount of heat absorbed by the refrigerant in the heat exchanger (37) is greatly reduced. As a result, the temperature of the refrigerant in the heat exchanger (37) is lowered, and the pressure of the low-pressure refrigerant becomes equal to or lower than the lower limit pressure and is out of the normal range. When the pressure of the low-pressure refrigerant decreases, the operation control means (54) decreases the operating capacity of the compressor (30) in an attempt to increase the pressure of the low-pressure refrigerant. For example, in the case of the air conditioner (10) in which the heat exchanger (37) to which the air of the blower fan (14) is supplied operates as a radiator, the refrigerant flowing through the heat exchanger (37) Of the physical quantity representing the state, for example, the operating capacity of the compressor (30) is adjusted such that the pressure of the high-pressure refrigerant discharged from the compressor (30) is lower than a predetermined upper limit pressure. That is, the range in which the pressure of the high-pressure refrigerant is lower than the upper limit pressure corresponds to the normal range. In such an air conditioner (10), when the blower fan (14) stops during the refrigeration cycle, the amount of heat released from the refrigerant in the heat exchanger (37) is greatly reduced. As a result, the temperature of the refrigerant in the heat exchanger (37) rises, and the pressure of the high-pressure refrigerant becomes equal to or higher than the upper limit pressure and falls outside the normal range. When the pressure of the high-pressure refrigerant increases, the operation control means (54) decreases the operating capacity of the compressor (30) in an attempt to decrease the pressure of the high-pressure refrigerant. As described above, when the blower fan (14) is stopped, the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) to which air is sent by the blower fan (14) is out of the normal range, and the compressor (30). When the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) in the low capacity state falls outside the normal range, the blower fan (14) is in a stopped state. Is detected. Then, in the fan motor rotating state, the cause that the blower fan (14) is stopped is not the stop of the fan motor (28), so that it is detected that the fan belt (29) is broken. Therefore, in the first invention, the abnormality determination means (55) is such that the physical quantity indicating the state of the refrigerant flowing through the heat exchanger (37) is in a predetermined time or more when the fan motor is rotating and in a low capacity state. When it is out of the normal range, it is determined that the fan belt (29) is broken.

According to a second invention, in the first invention, in the evaporation side refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the measuring means (46, 48, 50) includes the compressor (30 ) Is measured as the measurement value for determination, and the range in which the measurement value for determination is higher than a predetermined lower limit pressure is the normal range, while the refrigeration cycle in the evaporation side is The abnormality determination means (55) satisfies the condition that the measurement value for determination is not more than the lower limit pressure for a predetermined time or more in the fan motor rotating state and the low capacity state as the determination condition. In this case, it is determined that the fan belt (29) is broken.

In the second aspect of the invention, during the refrigeration cycle on the evaporation side, the pressure of the low-pressure refrigerant sucked into the compressor (30) is lower than the lower limit pressure over a predetermined time in the fan motor rotating state and in the low capacity state. When it is, the abnormality determining means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) stops during the evaporation-side refrigeration cycle, the heat absorption amount of the refrigerant in the heat exchanger (37) is greatly reduced, and the pressure of the low-pressure refrigerant becomes lower than the lower limit pressure. Moreover, the operating capacity of the compressor (30) decreases as the pressure of the low-pressure refrigerant decreases. In the second aspect of the invention, when performing the evaporation side refrigeration cycle, whether or not the blower fan (14) is stopped during the refrigeration cycle is determined by the pressure of the low-pressure refrigerant and the operating capacity of the compressor (30). It is determined whether or not the fan belt (29) is broken by using what can be determined.

In a third invention according to the first invention, in the refrigeration cycle on the evaporation side in which the heat exchanger (37) operates as an evaporator, the measuring means (46, 48, 50) includes the heat exchanger ( 37) the refrigerant evaporation temperature in 37) is measured as the determination measurement value, and the range in which the determination measurement value is higher than a predetermined lower limit temperature is the normal range, while the abnormality determination in the evaporation side refrigeration cycle is performed. The means (55) is configured such that the condition that the measurement value for determination is not more than the lower limit temperature for a predetermined time or more is satisfied as the determination condition in the fan motor rotating state and the low capacity state. Then, it is determined that the fan belt (29) is broken.

In the third aspect of the invention, when performing the evaporation side refrigeration cycle, it can be determined from the evaporation temperature and the operating capacity of the compressor (30) whether or not the blower fan (14) is stopped during the refrigeration cycle. Using it, it is determined whether or not the fan belt (29) is broken.

According to a fourth invention, in the first invention, in the refrigeration cycle on the heat radiation side where the heat exchanger (37) operates as a radiator, the measuring means (46, 48, 50) includes the compressor (30 ) Is measured as the measurement value for determination, and the range in which the measurement value for determination is lower than a predetermined upper limit pressure is the normal range, while the refrigeration cycle in the heat radiation side is The abnormality determination means (55) satisfies the condition that the determination measurement value is equal to or higher than the upper limit pressure for a predetermined time or more in the fan motor rotating state and the low capacity state. In this case, it is determined that the fan belt (29) is broken.

In the fourth aspect of the invention, the pressure of the high-pressure refrigerant discharged from the compressor (30) in the rotational state of the fan motor and in the low capacity state during the refrigeration cycle on the heat radiation side exceeds the upper limit pressure over a predetermined time. When it is, the abnormality determining means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) is stopped during the refrigeration cycle on the heat radiation side, the heat radiation amount of the refrigerant in the heat exchanger (37) is greatly reduced, and the pressure of the high pressure refrigerant becomes equal to or higher than the upper limit pressure. Moreover, the operating capacity of the compressor (30) decreases as the pressure of the high-pressure refrigerant increases. In the fourth aspect of the invention, when the refrigeration cycle on the heat radiation side is performed, whether or not the blower fan (14) is stopped during the refrigeration cycle is determined by the pressure of the high-pressure refrigerant and the operating capacity of the compressor (30). It is determined whether or not the fan belt (29) is broken by using what can be determined.

According to a fifth invention, in the first invention, in the refrigeration cycle on the heat radiation side where the heat exchanger (37) operates as a heat radiator, the measuring means (46, 48, 50) includes the heat exchanger ( 37) the refrigerant condensing temperature is measured as the determination measurement value, and the range in which the determination measurement value is lower than a predetermined upper limit temperature is the normal range, while the abnormality determination in the refrigeration cycle on the heat release side is performed. The means (55) is configured such that a condition that the determination measurement value is equal to or higher than the upper limit temperature for a predetermined time or more in the fan motor rotating state and the low capacity state is satisfied as the determination condition. Then, it is determined that the fan belt (29) is broken.

In 5th invention, when performing the refrigeration cycle by the side of heat radiation, it can be judged from a condensation temperature and the operating capacity of a compressor (30) whether the ventilation fan (14) has stopped during this refrigeration cycle. Using it, it is determined whether or not the fan belt (29) is broken.

According to a sixth invention, in the first invention , the heat exchanger (37) and the blower fan (in the casing (15) housing the heat exchanger (37) and the blower fan (14)). 14) is arranged to form an air passage (31) through which air flows upward, while the abnormality determining means (55) is used during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator. The temperature of the air below the heat exchanger (37) in the air passage (31) is not less than a predetermined time not only when the determination condition is satisfied in the fan motor rotation state but also in the fan motor rotation state. In the case where the temperature is lower than the predetermined low-temperature air reference value, it is determined that the fan belt (29) is broken.

In the sixth invention, during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator, even if the determination condition based on the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is not satisfied, When the fan motor is rotating and the temperature of the air below the heat exchanger (37) in the air passage (31) is lower than the predetermined low-temperature air reference value for a predetermined time or more, an abnormality is determined. The means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the air cooled by the heat exchanger (37) moves downward in the air passage (31) To do. As a result, the temperature of the air below the heat exchanger (37) in the air passage (31) decreases. As the blower fan (14) stops, the temperature of the refrigerant in the heat exchanger (37) decreases, so the temperature of the air below the heat exchanger (37) decreases relatively. In the sixth aspect of the invention, when the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the temperature of the air below the heat exchanger (37) in the air passage (31) Focusing on a relatively large decrease in air flow, it is determined whether the fan belt (29) is broken based on the temperature change of the air below the heat exchanger (37) in the air passage (31). The

According to a seventh invention, in the first invention , the heat exchanger (37) and the blower fan (in the casing (15) housing the heat exchanger (37) and the blower fan (14)). 14) is arranged to form an air passage (31) through which air flows upward, while the abnormality determining means (55) is used during the refrigeration cycle in which the heat exchanger (37) operates as a radiator. The temperature of the air above the heat exchanger (37) in the air passage (31) is not less than a predetermined time not only when the determination condition is satisfied in the fan motor rotation state but also in the fan motor rotation state. The fan belt (29) is also determined to be broken even when the predetermined high-temperature air reference value is exceeded.

In the seventh invention, during the refrigeration cycle in which the heat exchanger (37) operates as a radiator, even if the determination condition based on the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is not satisfied, If the temperature of the air above the heat exchanger (37) in the air passage (31) becomes higher than a predetermined high-temperature air reference value for a predetermined time or more with the fan motor rotating, an abnormality is determined. The means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as a radiator, the air heated by the heat exchanger (37) moves upward in the air passage (31). Moving. As a result, the temperature of the air above the heat exchanger (37) in the air passage (31) increases. As the blower fan (14) stops, the temperature of the refrigerant in the heat exchanger (37) rises, so the temperature of the air above the heat exchanger (37) rises relatively large. In the seventh aspect of the invention, when the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as a radiator, the air above the heat exchanger (37) in the air passage (31) Focusing on the relatively large rise in temperature, it is determined whether the fan belt (29) is broken based on the temperature change of the air above the heat exchanger (37) in the air passage (31). Is done.

According to an eighth aspect of the present invention, in the first aspect of the present invention , the casing (15) that houses the blower fan (14) and the heat exchanger (37) includes the heat exchanger (37) and the blower fan ( 14) is formed, and the air passage (31) is provided with a humidifier (19) for imparting moisture to the air that has passed through the heat exchanger (37), The abnormality determination means (55) is configured such that, during the operation of the humidifier (19), the rate of increase of the humidity of the air passage (31) per unit time is larger than a predetermined humidity reference value when the fan motor is rotating. In this case, it is determined that the fan belt (29) is broken without performing an operation for determining whether or not the determination condition is satisfied.

In the eighth invention, during the operation of the humidifier (19), when the rate of increase of the humidity of the air passage (31) per unit time is larger than a predetermined humidity reference value in the fan motor rotating state, Without performing the operation of determining whether or not the determination condition is satisfied, the abnormality determination means (55) determines that the fan belt (29) is broken. Here, when the blower fan (14) stops during operation of the humidifier (19), the humidity of the air passage (31) gradually increases. In this eighth invention, focusing on the fact that the humidity of the air passage (31) increases when the blower fan (14) stops during operation of the humidifier (19), the unit of humidity of the air passage (31) Based on the rate of increase per hour, it is determined whether or not the fan belt (29) is broken.

According to a ninth invention, in any one of the first to eighth inventions, the abnormality determination means (55) in the refrigeration cycle is a unit of a current value of a motor current supplied to the fan motor (28). When the rate of decrease per time is smaller than a predetermined current reference value, an operation is performed to determine whether or not the determination condition is satisfied.

In the ninth invention, it is determined whether or not the determination condition is satisfied when the rate of decrease in the current value of the motor current supplied to the fan motor (28) per unit time is smaller than a predetermined current reference value. Is performed. Here, when the fan belt (29) is broken, the load of the fan motor (28) is reduced, so that the motor current is reduced. That is, according to the rate of change of the current value of the motor current, it can be determined to some extent whether or not the fan belt (29) is broken. Therefore, in the ninth aspect , it is determined whether or not to perform the above operation based on the rate of change of the current value of the motor current.

According to a tenth aspect of the present invention, in any one of the first to eighth aspects, the abnormality determining means (55) in the refrigeration cycle has a rate of decrease per unit time in the rotational speed of the blower fan (14). When the rotation speed is smaller than the predetermined rotation speed reference value, an operation is performed to determine whether or not the determination condition is satisfied.

In the tenth invention, in that a smaller case than the rate of decrease predetermined rotational speed reference value per predetermined time of the rotational speed of the blower fan (14), the operation determines whether the determination condition is satisfied Done. Here, when the fan belt (29) breaks, the rotational speed of the blower fan (14) decreases. That is, according to the rate of change of the rotational speed of the blower fan (14), it can be determined to some extent whether or not the fan belt (29) is broken. For this reason, in this 10th invention, it is judged whether the said operation | movement is performed based on the change rate of the rotational speed of a ventilation fan (14).

In each of the first to fifth inventions, when the blower fan (14) stops, the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is outside the normal range, and the compressor (30) Since the operating capacity is reduced, the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is in the normal range over a predetermined time when the abnormality determining means (55) is in the fan motor rotating state and in the low capacity state. When it is off, it is determined that the fan belt (29) is broken. Therefore, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized.

In each of the second and third inventions, when the heat exchanger (37) performs a refrigeration cycle that operates as an evaporator, whether or not the blower fan (14) is stopped during the refrigeration cycle. However, it is determined whether or not the fan belt (29) is broken by using the fact that it can be determined from the pressure (or evaporation temperature) of the low-pressure refrigerant and the operating capacity of the compressor (30). For this reason, an air conditioner (10) capable of detecting that the fan belt (29) is broken is used as an air conditioner (10) that performs a refrigeration cycle in which the heat exchanger (37) operates as an evaporator. Can be realized.

In the fourth and fifth inventions, when the heat exchanger (37) performs a refrigeration cycle that operates as a radiator, whether or not the blower fan (14) is stopped during the refrigeration cycle. However, it is determined whether or not the fan belt (29) is broken by using the fact that it can be determined from the pressure (or condensing temperature) of the high-pressure refrigerant and the operating capacity of the compressor (30). For this reason, the air conditioner (10) capable of detecting that the fan belt (29) is broken is used as the air conditioner (10) for performing the refrigeration cycle in which the heat exchanger (37) operates as a radiator. Can be realized.

In the sixth aspect of the invention, if the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the air below the heat exchanger (37) in the air passage (31) Note that the fan belt (29) is broken or not based on the temperature change of the air below the heat exchanger (37) in the air passage (31). Determined. Even if the determination condition based on the change of the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is not satisfied, the temperature change of the air below the heat exchanger (37) in the air passage (31) If the condition is satisfied, it is determined that the fan belt (29) is broken. Therefore, it can be reliably detected that the fan belt (29) is broken.

In the seventh aspect of the invention, if the blower fan (14) stops during the refrigeration cycle in which the heat exchanger (37) operates as a radiator, the air above the heat exchanger (37) in the air passage (31) Note that the fan belt (29) is broken or not based on the temperature change of the air above the heat exchanger (37) in the air passage (31). Determined. Even if the determination condition based on the change in the physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) is not satisfied, the temperature change of the air above the heat exchanger (37) in the air passage (31) If the condition is satisfied, it is determined that the fan belt (29) is broken. Therefore, it can be reliably detected that the fan belt (29) is broken.

In the eighth aspect of the invention, paying attention to the fact that the humidity of the air passage (31) rises when the blower fan (14) stops during operation of the humidifier (19), the humidity of the air passage (31) Whether or not the fan belt (29) is broken is determined based on the rate of increase per unit time. Even before performing the operation of determining whether the determination condition is satisfied, if the humidity change rate of the air passage (31) satisfies a predetermined condition, it is determined that the fan belt (29) is broken. Is done. Therefore, it is possible to quickly detect that the fan belt (29) is broken during the operation of the humidifier (19).

In the ninth aspect , it is determined whether or not to perform an operation for determining whether or not the determination condition is satisfied based on the rate of change of the current value of the motor current. When the change rate of the current value of the motor current does not satisfy the predetermined condition, the above operation is not executed. Therefore, the above operation can be appropriately executed.

In the tenth aspect of the invention, it is determined whether or not to perform an operation for determining whether or not the determination condition is satisfied based on the rate of change in the rotational speed of the blower fan (14). When the change rate of the rotational speed of the blower fan (14) does not satisfy the predetermined condition, the above operation is not executed. Therefore, the above operation can be appropriately executed.

It is a schematic block diagram of the air conditioning apparatus which concerns on embodiment. It is a schematic block diagram of the indoor unit which concerns on embodiment. It is a flowchart of determination of the belt shortage concerning an embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the present embodiment is an air conditioner (10) including an outdoor unit (11) and an indoor unit (13). An outdoor circuit (21) is provided in the outdoor unit (11). An indoor circuit (22) is provided in the indoor unit (13). In this air conditioner (10), a refrigerant circuit that performs a vapor compression refrigeration cycle by connecting an outdoor circuit (21) and an indoor circuit (22) with a liquid side connecting pipe (23) and a gas side connecting pipe (24). (20) is configured.

《Outdoor unit configuration》
The outdoor circuit (21) of the outdoor unit (11) is provided with a compressor (30), an outdoor heat exchanger (34), an expansion valve (36), and a four-way switching valve (33). At one end of the outdoor circuit (21), a liquid side shut-off valve (25) to which the liquid side communication pipe (23) is connected is provided. The other end of the outdoor circuit (21) is provided with a gas side shut-off valve (26) to which the gas side communication pipe (24) is connected.

  The compressor (30) is configured as a hermetic and high-pressure dome type compressor. Electric power is supplied to the compressor (30) via an inverter. The capacity of the compressor (30) can be changed by changing the output frequency of the inverter to change the rotation speed of the motor. The discharge side of the compressor (30) is connected to the first port (P1) of the four-way switching valve (33) via the discharge pipe (40). The suction side of the compressor (30) is connected to the third port (P3) of the four-way switching valve (33) via the suction pipe (41).

  The outdoor heat exchanger (34) is configured as a cross fin type fin-and-tube heat exchanger. An outdoor fan (12) is provided in the vicinity of the outdoor heat exchanger (34). A fan motor is directly connected to the rotating shaft of the outdoor fan (12). In the outdoor heat exchanger (34), heat is exchanged between the outdoor air sent by the outdoor fan (12) and the refrigerant flowing through the outdoor heat exchanger (34). One end of the outdoor heat exchanger (34) is connected to the fourth port (P4) of the four-way switching valve (33). The other end of the outdoor heat exchanger (34) is connected to the liquid side shut-off valve (25) via the liquid pipe (42). The liquid pipe (42) is provided with an expansion valve (36) having a variable opening. In addition, the gas side closing valve (26) is connected to the second port (P2) of the four-way switching valve (33).

  The four-way selector valve (33) is in a first state in which the first port (P1) and the second port (P2) communicate with each other and the third port (P3) and the fourth port (P4) communicate with each other (FIG. 1). And a second state (FIG. 1) in which the first port (P1) and the fourth port (P4) communicate with each other and the second port (P2) and the third port (P3) communicate with each other. The state indicated by a broken line) can be switched.

  On the discharge side of the compressor (30) in the outdoor circuit (21), a discharge temperature sensor (47) for measuring the temperature of the refrigerant discharged from the compressor (30) and the refrigerant discharged from the compressor (30) And a discharge pressure sensor (48) for measuring the pressure. Also, on the suction side of the compressor (30), a suction temperature sensor (49) that measures the temperature of the refrigerant sucked into the compressor (30) and the pressure of the refrigerant sucked into the compressor (30) are measured. A suction pressure sensor (50) is provided. The outdoor circuit (21) includes an outdoor gas temperature sensor (43) for measuring the temperature of the refrigerant on the gas side of the outdoor heat exchanger (34), and the temperature of the refrigerant on the liquid side of the outdoor heat exchanger (34). And an outdoor liquid temperature sensor (44) for measuring.

《Composition of indoor unit》
The indoor circuit (22) of the indoor unit (13) is provided with an indoor heat exchanger (37). The indoor heat exchanger (37) is configured as a cross-fin type fin-and-tube heat exchanger. In the vicinity of the indoor heat exchanger (37), an indoor fan (14) composed of a sirocco fan is provided. The indoor fan (14) is configured by a blower fan (14) to which the power of the fan motor (28) is transmitted via the fan belt (29). In the indoor heat exchanger (37), heat is exchanged between the indoor air sent by the indoor fan (14) and the refrigerant flowing through the indoor heat exchanger (37).

  The indoor circuit (22) measures the temperature of the refrigerant on the gas side of the indoor heat exchanger (37) and the temperature of the refrigerant on the liquid side of the indoor heat exchanger (37). An indoor liquid temperature sensor (46) is provided.

  As shown in FIG. 2, the indoor unit (13) includes an indoor unit casing (15) that houses the components. The indoor unit casing (15) has a suction port (16) and a blowout port (17). In the indoor unit casing (15), an air passage (31) through which air flows upward from the suction port (16) toward the blowout port (17) is formed.

  The suction port (16) is formed in the lower part of the side wall of the indoor unit casing (15). A suction duct capable of switching between a state communicating with the room and a state communicating with the room is connected to the suction port (16). The blower outlet (17) is formed in the top plate of the indoor unit casing (15). A blow-out duct connected to a plurality of indoor spaces is connected to the blow-out opening (17).

  In the air passage (31), the indoor heat exchanger (37) is installed obliquely. The indoor heat exchanger (37) is arranged so as to partition the air passage (31) into the suction port (16) side and the blower outlet (17) side. The upper end of the indoor heat exchanger (37) is located near the front surface of the indoor unit casing (15) where the suction port (16) is formed. On the other hand, the lower end of the indoor heat exchanger (37) is located near the back surface of the indoor unit casing (15).

  In the air passage (31), the indoor fan (14) is disposed above the indoor heat exchanger (37). The blower outlet of the indoor fan (14) is connected to the blower outlet (17) of the indoor unit casing (15). A fan motor (28) is disposed obliquely below the indoor fan (14). A rubber fan belt (29) is wound around the motor-side pulley connected to the rotating shaft of the fan motor (28) and the fan-side pulley connected to the rotating shaft of the indoor fan (14). The fan belt (29) transmits the power of the fan motor (28) to the indoor fan (14). The air passage (31) is provided with a humidifier (19) for imparting moisture to the air that has passed through the indoor heat exchanger (37).

  Also, in the indoor unit casing (15), the intake air temperature sensor (51) that measures the temperature of air sucked from the suction port (16) and the humidity of the air sucked from the suction port (16) are measured. An intake air humidity sensor (52) that performs the above operation and a blown air temperature sensor (53) that measures the temperature of the air blown from the indoor fan (14) are provided.

  An electrical component unit (27) is installed on the bottom plate of the indoor unit casing (15). The electrical component unit (27) is provided with a power supply circuit for supplying power from the AC power source to the fan motor (28). A current detector for measuring the current value of the motor current flowing through the fan motor (28) is connected to the power supply circuit. The power supply circuit is connected to an overcurrent protection unit that stops the supply of power to the fan motor (28) when an overcurrent flows through the fan motor (28). For example, the overcurrent protection unit cuts off the motor current when the state in which the motor current exceeds a predetermined threshold continues for a predetermined time.

-Operation of refrigeration equipment-
Next, the operation of the air conditioner (10) will be described. In the air conditioner (10), the cooling operation and the heating operation are switched by the four-way switching valve (33). During the cooling operation and the heating operation, the suction duct is set in a state of communicating with the room.

  Further, the air conditioner (10) can perform a ventilation operation for driving the indoor fan (14) without executing the refrigeration cycle. During the ventilation operation, the suction duct is set to communicate with the outside of the room. Below, the flow of the refrigerant | coolant in air_conditionaing | cooling operation and heating operation is demonstrated.

<Cooling operation>
In the cooling operation, the four-way switching valve (33) is set to the second state. When the compressor (30) is operated in this state, the refrigerant circuit (20) performs a refrigeration cycle in which the outdoor heat exchanger (34) serves as a condenser and the indoor heat exchanger (37) serves as an evaporator. . This refrigeration cycle corresponds to the evaporation side refrigeration cycle. In the cooling operation, the opening degree of the expansion valve (36) is appropriately adjusted.

  Specifically, the refrigerant discharged from the compressor (30) is condensed by exchanging heat with outdoor air in the outdoor heat exchanger (34). The refrigerant condensed in the outdoor heat exchanger (34) is depressurized when passing through the expansion valve (36), and then is evaporated by exchanging heat with indoor air in the indoor heat exchanger (37). The refrigerant evaporated in the indoor heat exchanger (37) is sucked into the compressor (30) and compressed.

<Heating operation>
In the heating operation, the four-way switching valve (33) is set to the first state. When the compressor (30) is operated in this state, the refrigerant circuit (20) performs a refrigeration cycle in which the outdoor heat exchanger (34) serves as an evaporator and the indoor heat exchanger (37) serves as a condenser. . This refrigeration cycle corresponds to the refrigeration cycle on the heat radiation side. In the heating operation, the opening degree of the expansion valve (36) is appropriately adjusted.

  Specifically, the refrigerant discharged from the compressor (30) is condensed by exchanging heat with indoor air in the indoor heat exchanger (37). The refrigerant condensed in the indoor heat exchanger (37) is decompressed when passing through the expansion valve (36), and thereafter evaporates by exchanging heat with outdoor air in the outdoor heat exchanger (34). The refrigerant evaporated in the outdoor heat exchanger (34) is sucked into the compressor (30) and compressed.

"controller"
The air conditioner (10) includes a controller (35) that controls the operation of the air conditioner (10) based on a set temperature or the like input by a user. The controller (35) includes an operation control unit (54) constituting operation control means (54) for controlling the operation of the refrigerant circuit (20) and the operation of the fans (12, 14), and the fan belt (29) is broken. An abnormality determination unit (55) that constitutes an abnormality determination means (55) for determining whether or not the fan belt (29) is broken by the abnormality determination unit (55) And an abnormal alarm unit (56) for outputting a belt out alarm.

  The operation control unit (54) is configured to control the operation capacity of the compressor (30). In the operation control unit (54), the target evaporation temperature is set as the target value of the refrigerant evaporation temperature Te in the indoor heat exchanger (37) during the cooling operation. The initial value of the target evaporation temperature is set to 5 ° C., for example. The target evaporation temperature may vary depending on operating conditions, but is always set to a temperature higher than a predetermined lower limit temperature (for example, 0 ° C.). The operation control unit (54) during the cooling operation calculates the saturation temperature corresponding to the measured pressure of the suction pressure sensor (50) as the evaporation temperature Te, and the compressor so that the calculated evaporation temperature Te becomes the target evaporation temperature. Control the operating capacity of (30). During the cooling operation, the saturation pressure corresponding to the lower limit temperature becomes the lower limit pressure. During the cooling operation, the range in which the refrigerant evaporation temperature in the indoor heat exchanger (37) is higher than the lower limit temperature (the range in which the pressure of the low-pressure refrigerant sucked into the compressor (30) is higher than the lower limit pressure), The operating capacity of the compressor (30) is adjusted as a normal range that can be in a state where the blower fan (14) is driven by the fan motor (28) during the refrigeration cycle.

  In the operation control unit (54), the target condensing temperature is set as the target value of the refrigerant condensing temperature Tc in the indoor heat exchanger (37) during the heating operation. The initial value of the target condensation temperature is set to 45 ° C., for example. The target condensing temperature may vary depending on operating conditions, but is always set to a temperature lower than a predetermined upper limit temperature (for example, 50 ° C.). The operation control unit (54) during the heating operation calculates the saturation temperature corresponding to the measurement pressure of the discharge pressure sensor (48) as the condensation temperature Tc, and the compressor so that the calculated condensation temperature Tc becomes the target condensation temperature. Control the operating capacity of (30). During the heating operation, the saturation pressure corresponding to the upper limit temperature becomes the upper limit pressure. During heating operation, the range in which the condensation temperature of the refrigerant in the indoor heat exchanger (37) is lower than the upper limit temperature (the range in which the pressure of the high-pressure refrigerant discharged from the compressor (30) is lower than the upper limit pressure), The operating capacity of the compressor (30) is adjusted as a normal range.

  In addition, the operation control unit (54) forces the operating capacity of the compressor (30) when the measured pressure of the suction pressure sensor (50) is equal to or lower than a predetermined droop determination low pressure during cooling operation. Perform the low-pressure side drooping operation to lower. In addition, the operation control unit (54) forces the operating capacity of the compressor (30) when the measured pressure of the discharge pressure sensor (48) is equal to or higher than a predetermined droop determination high pressure during heating operation. Perform the high-pressure side drooping action to lower.

  The operation control unit (54) is configured to adjust the opening degree of the expansion valve (36). In the operation control unit (54), a target superheat degree (for example, 5 ° C.) is set as a target value of the superheat degree of the refrigerant flowing out of the evaporator. During cooling operation, the operation control unit (54) performs indoor heat exchange by subtracting the saturation temperature (evaporation temperature) corresponding to the measured pressure of the suction pressure sensor (50) from the measured temperature of the indoor gas temperature sensor (45). The degree of superheat of the refrigerant flowing out of the vessel (37) is calculated, and the opening degree of the expansion valve (36) is adjusted so that the calculated degree of superheat becomes the target degree of superheat. In addition, the operation control unit (54) during heating operation calculates a value obtained by subtracting a saturation temperature (evaporation temperature) corresponding to the measured pressure of the suction pressure sensor (50) from the measured temperature of the outdoor gas temperature sensor (43). The degree of superheat of the refrigerant flowing out from the heat exchanger (34) is calculated, and the opening degree of the expansion valve (36) is adjusted so that the calculated degree of superheat becomes the target degree of superheat.

  The abnormality determination unit (55) is configured to determine whether the belt has run out or not while determining whether the fan belt (29) is broken during the operation of the air conditioner (10). The determination of running out of the belt includes a fan stop confirmation operation, a suction humidity confirmation operation, and a main determination operation. Hereinafter, the determination of the belt running out will be described with reference to the flowchart shown in FIG.

In the determination of the belt out, step ST1 is first performed. In step ST1, the abnormality determination unit (55) performs an operation of determining whether or not the first condition is satisfied as the fan stop confirmation operation. The first condition is satisfied when at least one of the following Expression 1 and Expression 2 is satisfied. When the first condition is satisfied, the abnormality determination unit (55) determines that the fan motor (28) is rotating, and the process proceeds to step ST2. If the first condition is not satisfied, step ST1 is performed again. The fan motor rotation state is a state where the motor current is not interrupted by the overcurrent protection unit. Step ST2 and subsequent steps are performed when the fan motor is rotating.
Formula 1: Motor current decrease rate A <current reference value A1
Formula 2: Decrease rate N of fan rotation speed <reference speed N1 of rotation speed

  In the above formula 1, the motor current decrease rate A is the rate of decrease of the current value of the motor current supplied to the fan motor (28) per unit time. The abnormality determination unit (55) detects the rate of decrease of the motor current per unit time (for example, per second) detected by the current detection unit as the rate of decrease A of the motor current. The current reference value A1 is a determination threshold value set in advance in the abnormality determination unit (55).

  In Formula 2, the fan rotation speed decrease rate N is a decrease rate per unit time of the rotation speed of the indoor fan (14). The abnormality determination unit (55) uses the rate of decrease per unit time (for example, per second) of the detection speed of the rotation speed sensor provided on the rotation shaft of the indoor fan (14) as the decrease rate N of the fan rotation speed. To detect. The rotation speed reference value N1 is a determination threshold preset in the abnormality determination unit (55).

In step ST2, the abnormality determining unit (55) performs an operation of determining whether or not the second condition is satisfied as the suction humidity confirmation operation. The second condition is satisfied when a state in which the following Expression 3 is satisfied continues for a predetermined time t1 (for example, t1 = 5 minutes) during operation of the humidifier (19). If the second condition is satisfied, the abnormality determination unit (55) determines that the fan belt (29) is broken, and proceeds to step ST9. If the second condition is not satisfied, the process proceeds to step ST3.
Formula 3: Increase rate of suction humidity Hus> humidity reference value Hus1

  In the above formula 3, the increase rate Hus of the suction humidity is the increase rate per unit time (for example, per minute) of the measured humidity of the suction air humidity sensor (52). The measured humidity of the intake air humidity sensor (52) reflects the humidity of the air passage (31). The humidity reference value Hus1 is a determination threshold value (for example, 5% / min) preset in the abnormality determination unit (55).

  The abnormality determination unit (55) of the present embodiment has a predetermined time during which the rate of increase Hus per unit time of humidity in the air passage (31) is greater than the humidity reference value Hus1 in the fan motor rotating state. In the case of reaching, it is determined that the fan belt (29) is broken without performing a main determination operation described later.

  Step ST3 to step ST8 are main determination operations. In step ST3, the abnormality determination unit (55) confirms the operating state of the air conditioner (10), and determines to which step ST the process proceeds next. When the operation state of the air conditioner (10) is the cooling thermo-on state in which the compressor (30) is being operated during the cooling operation, the process proceeds to step ST4. Moreover, when the operation state of the air conditioner (10) is the heating thermo-on state in which the compressor (30) is being operated during the heating operation, the process proceeds to step ST6. If the operating state of the air conditioner (10) is neither the cooling thermo-on state nor the heating thermo-on state, the process proceeds to step ST8.

In step ST4, the abnormality determination unit (55) performs an operation of determining whether or not the third condition is satisfied. The third condition is that the condition in which the following Expression 4 is satisfied continues for a predetermined time t2 (for example, t2 = 5 minutes), and that the operation control unit (54) is in the low-pressure side drooping operation. This is established when at least one of the 3-2 condition and the 3rd-3 condition that the state in which the following Expression 5 is satisfied continues for a predetermined time t3 (for example, t3 = 5 minutes) is satisfied. If the third condition is satisfied, the abnormality determining unit (55) determines that the fan belt (29) is broken, and proceeds to step ST9. If the third condition is not satisfied, the process proceeds to step ST5.
Formula 4: Low pressure LP <first low pressure reference value LP1
Formula 5: Blowing temperature Tf + predetermined value> suction temperature Ts

  In the above equation 4, the low pressure LP is a measured pressure (measurement value for determination) of the suction pressure sensor (50). The suction pressure sensor (50) constitutes measuring means (46, 48, 50) that measures a physical quantity representing the state of the refrigerant flowing through the indoor heat exchanger (37) as a measurement value for determination. The first low-pressure reference value LP1 is a determination threshold (for example, 0.2 MPa) preset in the abnormality determination unit (55). The first low pressure reference value LP1 is set to a value lower than the lower limit pressure and higher than the drooping determination low pressure. The 3-1 condition is one of the determination conditions that the physical quantity representing the state of the refrigerant flowing through the indoor heat exchanger (37) is out of the normal range for a predetermined time or more. The third condition is that the pressure LP of the low-pressure refrigerant sucked into the compressor (30) is less than the first low-pressure side reference value LP1 lower than the lower limit pressure over a predetermined time. 1 constitutes a low pressure condition.

In the third condition, it may be determined whether or not the fan belt (29) is broken based on a change in the evaporation temperature Te. Specifically, in the third condition, instead of the 3-1 condition, a 3-4 condition that the duration of the state in which the following Expression 6 is satisfied is a predetermined time (for example, 5 minutes) or more is used.
Formula 6: Evaporation temperature Te <first low temperature reference value Te1

  In the above equation 6, the evaporation temperature Te is a measured temperature (measurement value for determination) of the indoor liquid temperature sensor (46). The indoor liquid temperature sensor (46) constitutes measuring means (46, 48, 50). The first low temperature reference value Te1 is a determination threshold set in advance in the abnormality determination unit (55), and is set to a value lower than the lower limit temperature. The third 3-4 condition is one of the above determination conditions, and the first low temperature side reference value in which the refrigerant evaporation temperature Te in the indoor heat exchanger (37) is lower than the lower limit temperature over a predetermined time. The first low-temperature condition is set to be less than Te1.

  Further, the 3-1 condition based on the low pressure LP and the 3-4 condition based on the evaporation temperature Te may be used in combination. In this case, the abnormality determining unit (55) determines that the fan belt (29) is broken when at least one of the 3-1 condition and the 3-4 condition is satisfied.

  Moreover, in the said Formula 5, suction temperature Ts is the measurement temperature of a suction air temperature sensor (51). The blowing temperature Tf is a temperature measured by the blowing air temperature sensor (53). In this embodiment, the value which added predetermined value (for example, 3 degreeC) to the blowing temperature Tf comprises the low temperature air reference value. The abnormality determination unit (55) of the present embodiment is not limited to the case where the 3-1 condition (the 3-4 condition) that constitutes the determination condition is satisfied, but also the room in the air passage (31) in the fan motor rotation state. Even when the condition that the duration of the state where the temperature Ts of the air below the heat exchanger (37) is lower than the low-temperature air reference value (Tf + predetermined value) reaches a predetermined time is satisfied, the fan belt (29 ) Is determined to be broken.

  In addition, instead of the 3-3 condition, the 3-5 condition that the duration of the state where the suction temperature Ts is lower than the predetermined suction determination temperature Ts1 is a predetermined time (for example, 5 minutes) or more is used. Also good. In this case, the suction determination temperature Ts1 constitutes a low-temperature air reference value and is set based on the target evaporation temperature. The suction determination temperature Ts1 is set to a temperature that is lower than the target evaporation temperature by a predetermined value, for example. Further, in addition to the third to fifth conditions, the third to sixth conditions that the duration of the state where the blowing temperature Tf is higher than the predetermined blowing determination temperature Tf1 is a predetermined time (for example, 5 minutes) or more are used. Also good. In this case, the abnormality determining unit (55) determines that the fan belt (29) is broken when at least one of the third to fifth conditions and the third to sixth conditions is satisfied.

In step ST5, the abnormality determining unit (55) performs an operation of determining whether or not the fourth condition is satisfied. The fourth condition is that the 4-1 condition that the operating capacity of the compressor (30) is in a low capacity range set in a controllable range and the condition in which the following Expression 7 is satisfied. The condition is satisfied when the 4-2 condition of continuing for a predetermined time t4 (for example, t4 = 5 minutes) is satisfied. When the fourth condition is satisfied, the abnormality determining unit (55) determines that the fan belt (29) is broken, and proceeds to step ST9. If the fourth condition is not satisfied, the process proceeds to step ST8.
Expression 7: Low pressure LP <second low pressure reference value LP2

  In Expression 7, the second low-pressure reference value LP2 is a determination threshold (for example, 0.57 MPa) preset in the abnormality determination unit (55). The second low pressure reference value LP2 is a refrigerant pressure at which the saturation temperature becomes, for example, −5 ° C., and is set to a value lower than the lower limit pressure and higher than the first low pressure reference value LP1. The 4-2 condition constitutes the determination condition. The fourth condition is that the pressure LP of the low-pressure refrigerant sucked into the compressor (30) is lower than the lower limit pressure and lower than the first low pressure for a predetermined time or more in the fan motor rotating state and in the low capacity state. The second low-pressure condition is configured to be lower than the second low-pressure side reference value LP2 higher than the side reference value LP1.

In the fourth condition, it may be determined whether or not the fan belt (29) is broken based on the change in the evaporation temperature Te. Specifically, in the fourth condition, instead of the 4-2 condition, a 4-3 condition that the duration of the state in which the following Expression 8 is satisfied is a predetermined time (for example, 5 minutes) or more is used.
Formula 8: Evaporation temperature Te <second low temperature reference value Te2

  In the above equation 8, the second low temperature reference value Te2 is a determination threshold (for example, −5 ° C.) preset in the abnormality determination unit (55). The second low temperature reference value Te2 is set to a value lower than the lower limit temperature and higher than the first low temperature reference value Te1. In this case, the 4th-3 condition constitutes a determination condition. The fourth condition is that the fan motor is in a rotating state and in a low capacity state, and the evaporation temperature Te of the refrigerant in the indoor heat exchanger (37) is lower than the lower limit temperature and lower than the first low temperature side over a predetermined time. The second low temperature condition is configured to be lower than the second low temperature side reference value Te2 higher than the reference value Te1. As in the case of the third condition, the 4-2 condition based on the low pressure LP and the 4-3 condition based on the evaporation temperature Te may be used in combination.

In step ST6, the abnormality determination unit (55) performs an operation of determining whether or not the fifth condition is satisfied. The fifth condition is that the condition in which the following Expression 9 is satisfied continues for a predetermined time t5 (for example, t5 = 5 minutes), and that the operation control unit (54) is in the high-pressure side drooping operation. It is satisfied when at least one of the 5-2 conditions is satisfied. If the fifth condition is satisfied, the abnormality determination unit (55) determines that the fan belt (29) is broken, and proceeds to step ST9. If the fifth condition is not satisfied, the process proceeds to step ST7.
Formula 9: High pressure HP> First high pressure reference value HP1

  In the above formula 9, the high pressure HP is the measurement pressure (measurement value for determination) of the discharge pressure sensor (48). The discharge pressure sensor (48) constitutes measuring means (46, 48, 50). The first high-pressure reference value HP1 is a determination threshold (for example, 3.5 MPa) preset in the abnormality determination unit (55). The first high pressure reference value HP1 is set to a value higher than the upper limit pressure and lower than the droop determination high pressure. The 5-1 condition is one of the determination conditions, and the first high-pressure side reference value in which the pressure HP of the high-pressure refrigerant discharged from the compressor (30) is higher than the upper limit pressure over a predetermined time. The first high pressure condition of exceeding HP1 is configured.

In the fifth condition, it may be determined whether or not the fan belt (29) is broken based on a change in the condensation temperature Tc. Specifically, in the fifth condition, instead of the 5-1 condition, the 5-3 condition that the duration of the state in which the following Expression 10 is satisfied is equal to or longer than a predetermined time (for example, 5 minutes) is used.
Expression 10: Condensation temperature Tc> first high temperature reference value Tc1

  In the above formula 10, the condensation temperature Tc is the measured temperature (measurement value for determination) of the indoor liquid temperature sensor (46). Moreover, 1st high temperature reference value Tc1 is the determination threshold value preset by the abnormality determination part (55). The first high temperature reference value Tc1 is set to a value higher than the upper limit temperature. The 5th-3 condition is one of the determination conditions, and the first high temperature side reference value Tc1 in which the refrigerant condensing temperature Tc in the indoor heat exchanger (37) is higher than the upper limit temperature for a predetermined time or more. The first high temperature condition of exceeding is configured.

  Further, the 5-1 condition based on the high pressure HP and the 5-3 condition based on the condensation temperature Tc may be used in combination. In this case, the abnormality determining unit (55) determines that the fan belt (29) is broken when at least one of the 5-1 condition and the 5-3 condition is satisfied.

In step ST7, the abnormality determining unit (55) performs an operation of determining whether or not the sixth condition is satisfied. The sixth condition is that the operating condition of the compressor (30) is set in the low capacity region and that the following equation 11 is satisfied is a predetermined time t6 (for example, t6 = 5 minutes). It is satisfied when at least one of the 6-2 conditions to continue is satisfied. If the sixth condition is satisfied, the abnormality determining unit (55) determines that the fan belt (29) is broken and proceeds to step ST9. If the sixth condition is not satisfied, the process proceeds to step ST8.
Formula 11: High pressure HP> Second high pressure reference value HP2

  In the above formula 11, the second high-pressure reference value HP2 is a determination threshold value (for example, 3.0 MPa) preset in the abnormality determination unit (55). The second high pressure reference value HP2 is a refrigerant pressure at which the saturation temperature becomes 50 ° C., for example, and is set to a value that is equal to or higher than the upper limit pressure and lower than the first high pressure reference value HP1. The 6-2 condition constitutes a determination condition. The sixth condition is that the pressure HP of the high-pressure refrigerant discharged from the compressor (30) is not less than the upper limit pressure and not less than the upper limit pressure for a predetermined time or more in the fan motor rotating state and in the low capacity state. The second high pressure condition is configured to be less than the second high pressure side reference value HP2 lower than the side reference value HP1.

In the sixth condition, it may be determined whether or not the fan belt (29) is broken based on a change in the condensation temperature Tc. Specifically, in the sixth condition, instead of the 6-2 condition, a 6-3 condition is used in which the duration of the state in which the following Expression 12 is satisfied is a predetermined time (for example, 5 minutes) or more.
Formula 12: Condensation temperature Tc> second high temperature reference value Tc2

  In the above formula 12, the second high temperature reference value Tc2 is a determination threshold value preset in the abnormality determination unit (55). The second high temperature reference value Tc2 is set to a value equal to or higher than the upper limit temperature and lower than the first high temperature reference value Tc1. In this case, the 6th-3 condition constitutes a determination condition. The sixth condition is that the fan motor is in a rotating state and in a low capacity state, and the refrigerant condensation temperature Tc in the indoor heat exchanger (37) is equal to or higher than the upper limit temperature for the predetermined time or longer and the first high temperature side. A second high temperature condition is set such that the second high temperature side reference value Tc2 that is lower than the reference value Tc1 is exceeded. As in the case of the fifth condition, the 6-2 condition based on the high pressure HP and the 6-3 condition based on the condensation temperature Tc may be used in combination.

In Step ST7, the abnormality determination unit (55) performs an operation of determining whether or not the seventh condition is satisfied in addition to the operation of determining whether or not the sixth condition is satisfied. The seventh condition is satisfied when the following expression 13 is satisfied for a predetermined time t7 (for example, t7 = 5 minutes).
Formula 13: Blowing temperature Tf> Heating determination temperature Tf2

  In the above equation 13, the heating determination temperature Tf2 is a determination threshold preset in the abnormality determination unit (55), and constitutes a high-temperature air reference value. The heating determination temperature Tf2 is set based on the target condensation temperature during the heating operation. The heating determination temperature Tf2 is set, for example, to a temperature that is higher than the target condensation temperature by a predetermined value.

  The abnormality determination unit (55) of the present embodiment is not limited to the case where the second high-pressure condition is satisfied, and the air temperature Tf above the indoor heat exchanger (37) in the air passage (31) in the fan motor rotation state. It is determined that the fan belt (29) is broken also when the condition that the duration of the state in which the temperature becomes higher than the heating determination temperature Tf2 reaches a predetermined time is satisfied.

  In step ST8, the abnormality determination unit (55) checks whether or not the operation state of the air conditioner (10) is set to the ventilation operation. If the abnormality determining unit (55) is set to the ventilation operation, the process proceeds to step ST9. If it is not set to the ventilation operation, the process proceeds to step ST1. The abnormality determination unit (55) during the ventilation operation determines that the fan belt (29) is broken if the first condition is satisfied in the fan stop confirmation operation.

  In step ST9, the abnormal alarm unit (56) outputs a belt out alarm indicating that the fan belt is out. The belt out alarm is output to a remote controller or the like. In step ST9, the abnormality determination unit (55) outputs a belt breakage detection signal to the abnormality notification unit (56). Then, when receiving the belt breakage detection signal, the abnormality reporting unit (56) outputs a belt breakage alarm to the remote controller or the like.

-Effect of the embodiment-
In the present embodiment, when the indoor fan (14) stops, the physical quantity of the refrigerant in the indoor heat exchanger (37) is out of the normal range, so that the refrigerant flowing through the indoor heat exchanger (37) in the fan motor rotation state When the physical quantity representing the state is out of the normal range for a predetermined time or more, the abnormality determination unit (55) determines that the fan belt (29) is broken. Therefore, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized.

  In this embodiment, when the operation capacity of the compressor (30) is adjusted so that the pressure of the low-pressure refrigerant does not become a predetermined lower limit pressure or less during the cooling operation, the indoor fan (14) is turned on during the cooling operation. Whether or not it is stopped can be determined by whether or not the pressure of the low-pressure refrigerant is equal to or lower than the lower limit pressure (or the evaporation temperature of the refrigerant in the indoor heat exchanger (37) is equal to or lower than the lower limit temperature), It is determined whether or not the fan belt (29) is broken. For this reason, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized as the air conditioner (10) performing the cooling operation.

  Further, in this embodiment, when the operating capacity of the compressor (30) is not immediately reduced to the low capacity region after the fan belt (29) is broken, it is quickly detected that the fan belt (29) is broken. The conditions that can be detected and the conditions that can quickly detect that the fan belt (29) is broken in response to a decrease in the pressure of the low-pressure refrigerant (or a decrease in the evaporation temperature) are used to determine whether the belt has run out. . For this reason, even if the operating capacity of the compressor (30) immediately decreases to the low capacity area after the fan belt (29) breaks, it does not immediately decrease to the low capacity area. It is possible to quickly detect that the fan belt (29) is broken.

  In the present embodiment, when the operating capacity of the compressor (30) is adjusted so that the pressure of the high-pressure refrigerant does not exceed a predetermined upper limit pressure during the heating operation, the indoor fan (14) is turned on during the heating operation. Utilizing that it can be determined whether or not the pressure of the high-pressure refrigerant is equal to or higher than the upper limit pressure (or whether the refrigerant condensing temperature in the indoor heat exchanger (37) is equal to or higher than the upper limit temperature). It is determined whether or not the fan belt (29) is broken. For this reason, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized as the air conditioner (10) that performs the heating operation.

  Further, in this embodiment, when the operating capacity of the compressor (30) is not immediately reduced to the low capacity region after the fan belt (29) is broken, it is quickly detected that the fan belt (29) is broken. The conditions that can be detected and the conditions that can quickly detect that the fan belt (29) is broken with respect to the increase in the pressure of the high-pressure refrigerant (or the increase in the condensation temperature) are used to determine whether the belt has run out. . For this reason, even if the operating capacity of the compressor (30) immediately decreases to the low capacity area after the fan belt (29) breaks, it does not immediately decrease to the low capacity area. It is possible to quickly detect that the fan belt (29) is broken.

  In the present embodiment, when the indoor fan (14) is stopped, the physical quantity representing the state of the refrigerant flowing through the indoor heat exchanger (37) is outside the normal range, and the operating capacity of the compressor (30) is reduced. Therefore, the duration of the state in which the physical quantity representing the state of the refrigerant flowing through the indoor heat exchanger (37) is outside the normal range in a state where the abnormality determination unit (55) is in the fan motor rotating state and in the low capacity state is a predetermined time. Is reached, it is determined that the fan belt (29) is broken. Therefore, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized.

  In this embodiment, when the operation capacity of the compressor (30) is adjusted so that the pressure of the low-pressure refrigerant does not become a predetermined lower limit pressure or less during the cooling operation, the indoor fan (14) is turned on during the cooling operation. The fan belt (29) breaks using the fact that whether or not it is stopped can be judged from the pressure of the low-pressure refrigerant (or the evaporation temperature correlated with the pressure of the low-pressure refrigerant) and the operating capacity of the compressor (30). It is determined whether or not. For this reason, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized as the air conditioner (10) performing the cooling operation.

  In the present embodiment, when the operating capacity of the compressor (30) is adjusted so that the pressure of the high-pressure refrigerant does not exceed a predetermined upper limit pressure during the heating operation, the indoor fan (14) is turned on during the heating operation. The fan belt (29) is broken by using the fact that whether or not it is stopped can be judged from the pressure of the high-pressure refrigerant (or the condensing temperature correlated with the pressure of the high-pressure refrigerant) and the operating capacity of the compressor (30). It is determined whether or not. For this reason, the air conditioner (10) capable of detecting that the fan belt (29) is broken can be realized as the air conditioner (10) that performs the heating operation.

  Further, in this embodiment, when the indoor fan (14) stops during the cooling operation, the temperature of the air below the indoor heat exchanger (37) in the air passage (31) is relatively greatly reduced. Based on the temperature change of the air below the indoor heat exchanger (37) in the air passage (31), it is determined whether or not the fan belt (29) is broken. Even if the determination condition based on the change of the physical quantity of the refrigerant in the indoor heat exchanger (37) is not satisfied, the temperature change of the air below the indoor heat exchanger (37) in the air passage (31) satisfies the predetermined condition. If it is satisfied, it is determined that the fan belt (29) is broken. Therefore, it can be reliably detected that the fan belt (29) is broken.

  Further, in the present embodiment, focusing on the fact that the temperature of the air above the indoor heat exchanger (37) in the air passage (31) rises relatively large when the indoor fan (14) stops during the heating operation. Based on the temperature change of the air above the indoor heat exchanger (37) in the air passage (31), it is determined whether or not the fan belt (29) is broken. Even if the determination condition based on the change in the physical quantity of the refrigerant in the indoor heat exchanger (37) is not satisfied, the temperature change of the air above the indoor heat exchanger (37) in the air passage (31) satisfies the predetermined condition. If it is satisfied, it is determined that the fan belt (29) is broken. Therefore, it can be reliably detected that the fan belt (29) is broken.

  In this embodiment, focusing on the fact that the humidity of the air passage (31) increases when the indoor fan (14) stops during operation of the humidifier (19), the unit of humidity of the air passage (31) Based on the rate of increase per hour, it is determined whether or not the fan belt (29) is broken. Even before performing the operation of determining whether the determination condition is satisfied, if the humidity change rate of the air passage (31) satisfies a predetermined condition, it is determined that the fan belt (29) is broken. Is done. Therefore, it is possible to quickly detect that the fan belt (29) is broken during the operation of the humidifier (19).

  Further, in the present embodiment, it is determined whether or not to perform an operation for determining whether or not the determination condition is satisfied based on the rate of change of the current value of the motor current. When the change rate of the current value of the motor current does not satisfy the predetermined condition, the above operation is not executed. Therefore, the above operation can be appropriately executed.

  Further, in the present embodiment, it is determined whether or not to perform an operation for determining whether or not the determination condition is satisfied based on the rate of change in the rotational speed of the indoor fan (14). When the rate of change of the rotational speed of the indoor fan (14) does not satisfy a predetermined condition, the above operation is not executed. Therefore, the above operation can be appropriately executed.

<< Other Embodiments >>
About the said embodiment, it is good also as the following structures.

  About the said embodiment, the abnormality determination part (55) may be comprised so that only one of step ST4 and step ST5 may be performed as a determination of belt out in a cooling thermostat state.

  Moreover, about the said embodiment, the abnormality determination part (55) may be comprised so that only one of step ST6 and step ST7 may be performed as determination of the belt running out in a heating thermo state.

  In the above embodiment, the refrigerant circuit (20) may be configured to perform a supercritical cycle in which the high pressure of the refrigeration cycle is set to a value higher than the critical pressure of the refrigerant. In this case, in a normal refrigeration cycle in which the high pressure of the refrigeration cycle is set to a value lower than the critical pressure of the refrigerant, a heat exchanger that serves as a condenser operates as a gas cooler. For example, carbon dioxide is used as the refrigerant. In this case, the abnormality determination unit (55) during the heating operation uses the temperature of the refrigerant at a fixed position such as the inlet of the indoor heat exchanger (37) as a measurement value for determination instead of the condensation temperature, and determines the fan belt (29 ) Is broken or not.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for an air conditioner including a blower fan in which power of a fan motor is transmitted via a fan belt.

10 Air Conditioner 14 Indoor Fan (Blower Fan)
20 Refrigerant circuit 28 Fan motor 29 Fan belt 30 Compressor 35 Controller 37 Indoor heat exchanger (heat exchanger)
54 Operation control unit (operation control means)
55 Abnormality determination unit (abnormality determination means)
56 Abnormal Report Section

Claims (19)

A refrigerant circuit (20) provided with a compressor (30) and a heat exchanger (37) to circulate refrigerant and perform a refrigeration cycle;
A blower fan (14) for sending air to the heat exchanger (37);
A fan motor (28) for driving the blower fan (14);
An air conditioner comprising a fan belt (29) for transmitting power of the fan motor (28) to the blower fan (14),
Measuring means (46, 48, 50) for measuring a physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) as a measurement value for determination;
Abnormality determination means (55) for determining that the fan belt (29) is broken when a predetermined determination condition is satisfied in a state where the fan motor (28) is rotating during the refrigeration cycle. And
The determination condition is such that the determination measurement value is within a normal range in which the blower fan (14) is driven by the fan motor (28) during the refrigeration cycle for a predetermined time or more. An air conditioner characterized in that it is in a condition of being disconnected. In claim 1,
In the evaporation side refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the measuring means (46, 48, 50) determines the pressure of the low-pressure refrigerant sucked into the compressor (30) for the determination. While measuring as a measurement value, the range in which the measurement value for determination is higher than a predetermined lower limit pressure is the normal range,
The abnormality determining means (55) in the evaporation side refrigeration cycle is characterized in that the determination condition is that the measurement value for determination is not more than the lower limit pressure for a predetermined time or more in the rotation state of the fan motor. The air conditioner is characterized in that it is determined that the fan belt (29) is broken. In claim 2,
In the evaporation side refrigeration cycle, the operating capacity of the compressor (30) is adjusted such that the determination measurement value is higher than the lower limit pressure,
The abnormality determination means (55) in the evaporative refrigeration cycle has the determination measurement value less than a first low pressure reference value lower than the lower limit pressure over a predetermined time in the fan motor rotating state. The first low-pressure condition is set not only in the case where the determination condition is satisfied, but also in the low-capacity region where the operation capacity of the compressor (30) is controllable in the fan motor rotation state. When the second low-pressure condition is satisfied that the measurement value for determination is lower than the lower limit pressure and lower than the second low-pressure reference value higher than the first low-pressure reference value for a predetermined time or more in a state And determining that the fan belt (29) is broken. In claim 1,
In the evaporation side refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the measuring means (46, 48, 50) determines the refrigerant evaporation temperature in the heat exchanger (37) as the measurement value for determination. While the range in which the measurement value for determination is higher than a predetermined lower limit temperature is the normal range,
The abnormality determining means (55) in the evaporation side refrigeration cycle is such that the determination condition is that the measured value for determination is not more than the lower limit temperature for a predetermined time or more in the fan motor rotating state. The air conditioner is characterized in that it is determined that the fan belt (29) is broken. In claim 4,
In the evaporation side refrigeration cycle, the operating capacity of the compressor (30) is adjusted so that the measurement value for determination is higher than the lower limit temperature,
The abnormality determination means (55) in the evaporation side refrigeration cycle has the measurement value for determination below the first low temperature reference value lower than the lower limit temperature over a predetermined time in the fan motor rotating state. The first low-temperature condition is set not only in the case where the determination condition is satisfied, but also in the low-capacity region where the operation capacity of the compressor (30) is controllable in the fan motor rotation state. A second low temperature condition is satisfied that the measured value for determination is lower than the lower limit temperature and lower than a second low temperature reference value higher than the first low temperature reference value for a predetermined time or more in a state And determining that the fan belt (29) is broken. In claim 1,
In the heat-release side refrigeration cycle in which the heat exchanger (37) operates as a radiator, the measuring means (46, 48, 50) uses the pressure of the high-pressure refrigerant discharged from the compressor (30) for the determination. While measuring as a measurement value, the range in which the measurement value for determination is lower than a predetermined upper limit pressure is the normal range,
The abnormality determining means (55) in the refrigeration cycle on the heat radiation side is based on the condition that the measurement value for determination is equal to or higher than the upper limit pressure for a predetermined time or more in the fan motor rotating state. The air conditioner is characterized in that it is determined that the fan belt (29) is broken. In claim 6,
In the refrigeration cycle on the heat dissipation side, the operating capacity of the compressor (30) is adjusted so that the measurement value for determination is lower than the upper limit pressure,
The abnormality determining means (55) in the refrigeration cycle on the heat release side is said that the determination measurement value exceeds a first high pressure reference value higher than the upper limit pressure over a predetermined time in the fan motor rotating state. Not only when the first high-pressure condition is satisfied as the determination condition, but also in a state where the fan motor is rotated and the operating capacity of the compressor (30) is set in a controllable low-capacity region. The fan belt also when the second high pressure condition that the measured value for determination exceeds the upper limit pressure for a predetermined time or more and exceeds a second high pressure reference value lower than the first high pressure reference value is satisfied. (29) It determines with having fractured, The air conditioning apparatus characterized by the above-mentioned. In claim 1,
In the heat-release side refrigeration cycle in which the heat exchanger (37) operates as a radiator, the measuring means (46, 48, 50) measures the condensation temperature of the refrigerant in the heat exchanger (37) as the measured value for determination. While the range in which the measurement value for determination is lower than a predetermined upper limit temperature is the normal range,
The abnormality determining means (55) in the refrigeration cycle on the heat radiation side is based on the condition that the measured value for determination is equal to or higher than the upper limit temperature for a predetermined time or more in the rotation state of the fan motor. The air conditioner is characterized in that it is determined that the fan belt (29) is broken. In claim 8,
In the refrigeration cycle on the heat release side, the operating capacity of the compressor (30) is adjusted so that the measurement value for determination is lower than the upper limit temperature,
The abnormality determining means (55) in the refrigeration cycle on the heat radiation side is said that the determination measurement value exceeds the first high temperature reference value higher than the upper limit temperature over a predetermined time in the fan motor rotating state. Not only when the first high temperature condition is satisfied as the determination condition, but also in the fan motor rotating state and in a state where the operating capacity of the compressor (30) is set to a controllable low capacity region, The fan belt also when the second high temperature condition that the measured value for determination exceeds the upper limit temperature for a predetermined time or more and exceeds the second high temperature reference value lower than the first high temperature reference value is satisfied. (29) It determines with having fractured, The air conditioning apparatus characterized by the above-mentioned. A refrigerant circuit (20) provided with a compressor (30) having a variable operating capacity and a heat exchanger (37) to circulate the refrigerant and perform a refrigeration cycle;
A blower fan (14) for sending air to the heat exchanger (37);
A fan motor (28) for driving the blower fan (14);
An air conditioner comprising a fan belt (29) for transmitting power of the fan motor (28) to the blower fan (14),
Measuring means (46, 48, 50) for measuring a physical quantity representing the state of the refrigerant flowing through the heat exchanger (37) as a measurement value for determination;
The operating capacity of the compressor (30) is adjusted so that the determination measurement value falls within a predetermined normal range during the refrigeration cycle, and when the determination measurement value is out of the normal range, the compression is performed. Operation control means (54) for reducing the operation capacity of the machine (30);
In a low capacity state where the fan motor (28) is rotating during the refrigeration cycle and the operating capacity of the compressor (30) is in a controllable low capacity region. An abnormality determining means (55) for determining that the fan belt (29) is broken when a predetermined determination condition is satisfied,
The air conditioner is characterized in that the determination condition is a condition that the determination measurement value is out of the normal range for a predetermined time or more. In claim 10,
In the evaporation side refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the measuring means (46, 48, 50) determines the pressure of the low-pressure refrigerant sucked into the compressor (30) for the determination. While measuring as a measurement value, the range in which the measurement value for determination is higher than a predetermined lower limit pressure is the normal range,
The abnormality determination means (55) in the evaporation side refrigeration cycle is such that the determination measurement value is not more than the lower limit pressure for a predetermined time or more in the fan motor rotating state and in the low capacity state. When the above condition is satisfied as the determination condition, it is determined that the fan belt (29) is broken. In claim 10,
In the evaporation side refrigeration cycle in which the heat exchanger (37) operates as an evaporator, the measuring means (46, 48, 50) determines the refrigerant evaporation temperature in the heat exchanger (37) as the measurement value for determination. While the range in which the measurement value for determination is higher than a predetermined lower limit temperature is the normal range,
The abnormality determination means (55) in the evaporation side refrigeration cycle is such that the determination measurement value is not more than the lower limit temperature for a predetermined time or more in the fan motor rotating state and in the low capacity state. When the above condition is satisfied as the determination condition, it is determined that the fan belt (29) is broken. In claim 10,
In the heat-release side refrigeration cycle in which the heat exchanger (37) operates as a radiator, the measuring means (46, 48, 50) uses the pressure of the high-pressure refrigerant discharged from the compressor (30) for the determination. While measuring as a measurement value, the range in which the measurement value for determination is lower than a predetermined upper limit pressure is the normal range,
The abnormality determining means (55) in the refrigeration cycle on the heat radiation side has the measured value for determination equal to or higher than the upper limit pressure for a predetermined time or more in the fan motor rotating state and in the low capacity state. When the above condition is satisfied as the determination condition, it is determined that the fan belt (29) is broken. In claim 10,
In the heat-release side refrigeration cycle in which the heat exchanger (37) operates as a radiator, the measuring means (46, 48, 50) measures the condensation temperature of the refrigerant in the heat exchanger (37) as the measured value for determination. While the range in which the measurement value for determination is lower than a predetermined upper limit temperature is the normal range,
The abnormality determination means (55) in the refrigeration cycle on the heat radiation side is such that the determination measurement value is equal to or higher than the upper limit temperature for a predetermined time or more in the fan motor rotating state and in the low capacity state. When the above condition is satisfied as the determination condition, it is determined that the fan belt (29) is broken. In claim 1 or 10,
In the casing (15) that houses the heat exchanger (37) and the blower fan (14), the heat exchanger (37) and the blower fan (14) are arranged so that air flows upward. While the passage (31) is formed,
The abnormality determination means (55) is used not only when the determination condition is satisfied in the fan motor rotation state during the refrigeration cycle in which the heat exchanger (37) operates as an evaporator, but also in the fan motor rotation state. Even when the temperature of the air below the heat exchanger (37) in the air passage (31) is lower than a predetermined low-temperature air reference value for a predetermined time or more, the fan belt (29) It is determined that the air is broken. In claim 1 or 10,
In the casing (15) that houses the heat exchanger (37) and the blower fan (14), the heat exchanger (37) and the blower fan (14) are arranged so that air flows upward. While the passage (31) is formed,
The abnormality determination means (55) is used not only when the determination condition is satisfied in the fan motor rotation state but also in the fan motor rotation state during the refrigeration cycle in which the heat exchanger (37) operates as a radiator. Even when the temperature of the air above the heat exchanger (37) in the air passage (31) becomes higher than a predetermined high-temperature air reference value for a predetermined time or more, the fan belt (29) It is determined that the air is broken. In claim 1 or 10,
An air passage (31) in which the heat exchanger (37) and the blower fan (14) are arranged is formed in the casing (15) that houses the blower fan (14) and the heat exchanger (37). And
The air passage (31) is provided with a humidifier (19) for imparting moisture to the air that has passed through the heat exchanger (37),
The abnormality determination means (55) is configured such that, during the operation of the humidifier (19), the rate of increase of the humidity of the air passage (31) per unit time is larger than a predetermined humidity reference value when the fan motor is rotating. In this case, the air conditioner determines that the fan belt (29) is broken without performing an operation of determining whether or not the determination condition is satisfied. In any one of Claims 1 thru | or 17,
The abnormality determination means (55) during the refrigeration cycle is configured to perform the determination when the rate of decrease in the current value of the motor current supplied to the fan motor (28) per unit time is smaller than a predetermined current reference value. An air conditioner that performs an operation of determining whether or not a condition is satisfied. In any one of Claims 1 thru | or 17,
The abnormality determination means (55) during the refrigeration cycle satisfies whether the determination condition is satisfied when the rate of decrease in rotational speed of the blower fan (14) per unit time is smaller than a predetermined rotational speed reference value. An air conditioner that performs an operation of determining whether or not.

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