Compressor system and refrigerating device

Abstract

To make it possible to detect a sign of a failure in object portions of a compressor at an early stage.SOLUTION: A compressor system (40) comprises a compressor (50), and a prediction device (21) for predicting a failure in bearings (79, 69, and 93) and a drive shaft (80) of the compressor (50). The compressor (50) comprises a motor (55), a compression part (60), the drive shaft (80), and the bearings (79, 69, and 93). Lubricating oil is supplied from a common oil supply source to the compression part (60) and sliding portions of the drive shaft (80) and the bearings (79, 69, and 93). The prediction device (21) comprises a failure prediction unit (23) for predicting the failure in the bearings (79, 69, and 93) and the drive shaft (80) on the basis of a change in an index indicating a decrease in sealing performance of a compression chamber (61).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a compressor system and a refrigeration device. [Background technology]

[0002] Patent Document 1 discloses a failure symptom detection device for an air conditioner that includes a compressor including a motor and a drive device configured to output a three-phase current to the motor. This failure symptom detection device detects a failure symptom of an air conditioner, for example, when a lack of lubricant causes solid contact in which metal parts directly contact each other at the sliding parts of the compressor, which increases frictional resistance and generates frictional heat, causing the metal parts to adhere to each other and causing the compressor to stop (air conditioner to break down). The failure symptom detection device is able to accurately detect a failure symptom of an air conditioner by analyzing the q-axis current of the motor, because the output torque of the motor increases when the sliding parts of the compressor are damaged and the frictional resistance increases, and the q-axis current of the motor, which is hardly affected by electrical noise, fluctuates in almost the same way as the output torque of the motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6173530 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned failure symptom detection device is slow in detecting the symptoms of failure, and is unable to predict failure of the target part (sliding part) of the compressor before the target part is significantly damaged.

[0005] It is an object of the present disclosure to be able to detect symptoms of failure of a compressor part before significant damage occurs to that part. [Means for solving the problem]

[0006] A first aspect of the present disclosure is a compressor comprising: a motor (55); a compression section (60) having a compression chamber (61) that draws in and compresses a fluid; a drive shaft (80) connected to the motor (55) and driving the compression section (60); and bearings (79, 69, 93) that support the drive shaft (80), in which lubricating oil is supplied from a common oil supply source to the compression section (60) and sliding parts of the drive shaft (80) and the bearings (79, 69, 93). and a prediction device (21) that predicts failures in the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50), wherein the prediction device (21) includes a failure prediction unit (23) that predicts failures in the bearings (79, 69, 93) and the drive shaft (80) based on a change in an index showing a deterioration in sealing property of the compression chamber (61).

[0007] Here, the failure of the bearings (79, 69, 93) and the drive shaft (80) refers to a state in which the bearings (79, 69, 93) and the drive shaft (80) are unable to operate, while the damage to the bearings (79, 69, 93) and the drive shaft (80) refers to a state in which the bearings (79, 69, 93) and the drive shaft (80) are not unable to operate (broken down), but are severely worn or damaged, resulting in reduced functionality.

[0008] According to the compressor system of the first aspect, after a decrease in the oil level in the oil source occurs, symptoms of failure in the bearings (79, 69, 93) and the drive shaft (80) can be detected before the bearings (79, 69, 93) and the drive shaft (80) are significantly damaged.

[0009] A second aspect is the compressor system of the first aspect, characterized in that the indicator is an internal pressure of the compression chamber (61).

[0010] According to the compressor system of the second aspect, instead of detecting a decrease in the amount of seal oil, which is difficult to detect, the internal pressure of the compression chamber (61), which changes in conjunction with a change in the amount of seal oil, is detected to predict failures in the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50), thereby making it easy to predict failures.

[0011] A third aspect is the compressor system of the first aspect, characterized in that the index is a polytropic exponent in the compression process of the compression chamber (61).

[0012] According to the compressor system of the third aspect, instead of detecting a decrease in the amount of seal oil, which is difficult to detect, the polytropic index, which changes in conjunction with a change in the amount of seal oil, is detected to predict failures in the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50). This makes it easy to predict failures.

[0013] In a fourth aspect, in the first aspect, the indicator is the temperature of the gas discharged from the compression section (60).

[0014] According to the compressor system of the fourth aspect, instead of detecting a decrease in the amount of seal oil, which is difficult to detect, the temperature of the discharge gas, which changes in conjunction with a change in the amount of seal oil, is detected to predict failures in the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50), making it easy to predict failures.

[0015] A fifth aspect is the first aspect, wherein the index is the amount of work done by the compressor (50) or the amount of power input to the motor (55).

[0016] According to the compressor system of the fifth aspect, instead of detecting a decrease in the amount of seal oil, which is difficult to detect, the amount of work done by the compressor (50) or the amount of power input to the motor (55), which changes in conjunction with a change in the amount of seal oil, is detected to predict failures in the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50). This makes it easy to predict failures.

[0017] A sixth aspect is the first aspect, wherein the index is a refrigeration capacity of a refrigeration system (10) including the compressor (50).

[0018] According to the compressor system of the sixth aspect, instead of detecting a decrease in the amount of seal oil, which is difficult to detect, the refrigeration capacity of the refrigeration system (10), which changes in conjunction with a change in the amount of seal oil, is detected to predict failures in the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50). This makes it easy to predict failures.

[0019] A seventh aspect is the first aspect, wherein the indicator is a waveform of the compression torque of the compressor (50).

[0020] According to the compressor system of the seventh aspect, instead of detecting a decrease in the amount of seal oil, which is difficult to detect, the compressor system detects the waveform of the compression torque that changes in conjunction with a change in the amount of seal oil to predict failures in the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50), making it easy to predict failures.

[0021] An eighth aspect is the first aspect, characterized in that the index is a waveform of a motor signal correlated with at least one of a voltage, a current, and a power of the motor (55).

[0022] According to the compressor system of the eighth aspect, instead of detecting a decrease in the amount of seal oil, which is difficult to detect, the waveform of the motor signal, which changes in conjunction with the change in the amount of seal oil, is detected to predict failures in the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50), making it easy to predict failures.

[0023] A ninth aspect is the first aspect, wherein the indicator is a waveform of a vibration signal indicating the vibration of the compressor (50) or the intensity of sound generated in the compressor (50).

[0024] According to the compressor system of the ninth aspect, instead of detecting a decrease in the amount of seal oil, which is difficult to detect, the compressor system detects the vibration of the compressor (50) or the waveform of a vibration signal indicating the intensity of sound generated in the compressor (50), which changes in conjunction with a change in the amount of seal oil, to thereby predict failures in the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50). This makes it easy to predict failures.

[0025] The tenth aspect is the first aspect, wherein the compressor (50) is provided with an oil reservoir (95) which serves as an oil supply source for storing lubricating oil to be supplied to the compression section (60) and the sliding parts of the drive shaft (80) and the bearings (79, 69, 93), and the compressor (50) is characterized in that, when the amount of lubricating oil in the oil reservoir (95) decreases, the amount of lubricating oil sealing the compression chamber (61) decreases before insufficient lubrication occurs in the sliding parts of the drive shaft (80) and the bearings (79, 69, 93).

[0026] According to the compressor system of the tenth aspect, after a decrease in the amount of oil in the oil reservoir (95) occurs, symptoms of failure of the drive shaft (80) and the bearings (79, 69, 93) can be detected before the drive shaft (80) and the bearings (79, 69, 93) are severely damaged due to insufficient lubrication.

[0027] An eleventh aspect is the compressor system of the tenth aspect, characterized in that the oil reservoir (95) is formed at the bottom of the compressor (50) so that the pressure of the high-pressure discharge gas discharged from the compression chamber (61) acts on the oil reservoir (95), and the compressor (50) includes a first oil supply passage (88) that guides the lubricating oil in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the bearings (79, 69, 93) and a second oil supply passage (89) that guides the lubricating oil in the oil reservoir (95) to the compression section (60), and an inlet (89a) of the second oil supply passage (89) is positioned above an inlet (88a) of the first oil supply passage (88).

[0028] According to the compressor system of the eleventh aspect, by simply improving the oil supply passage (87), it is possible to easily configure a compressor (50) in which, when the amount of oil in the oil reservoir (95) decreases, a sealing failure due to a decrease in the amount of lubricating oil sealing the compression chamber (61) occurs before a lubrication failure occurs in the sliding parts of the drive shaft (80) and the bearings (79, 69, 93).

[0029] In a twelfth aspect, in the compressor system of the tenth aspect, the compressor (50) includes an oil supply passage (87) that guides the lubricating oil in the oil sump (95) to the compression section (60) and sliding portions of the drive shaft (80) and the bearings (79, 69, 93). The oil supply passage (87) is configured to supply the lubricating oil in the oil sump (95) to the compression section (60) and sliding portions of the drive shaft (80) and the bearings (79, 69, 93) at a predetermined oil supply rate. The predetermined oil supply rate is a rate at which an amount of lubricating oil in the oil sump (95) is increased by a factor of 10 or more. When the amount of lubricating oil supplied to the compression section (60) and the sliding parts of the drive shaft (80) and the bearings (79, 69, 93) decreases below the normal amount when lubricating oil is constantly supplied to the compression section (60) and the sliding parts of the drive shaft (80) and the bearings (79, 69, 93) by (87), the amount of oil supplied to the compression section (60) falls below the amount of oil required to seal the compression chamber (61) before the amount of oil supplied to the sliding parts of the drive shaft (80) and the bearings (79, 69, 93) falls below the amount of oil required to avoid poor lubrication at the sliding parts of the drive shaft (80) and the bearings (79, 69, 93).

[0030] According to the compressor system of the twelfth aspect, by simply improving the oil supply passage (87), it is possible to easily configure a compressor (50) in which, when the amount of lubricating oil in the oil reservoir (95) decreases, a sealing failure due to a decrease in the amount of lubricating oil sealing the compression chamber (61) occurs before a lubrication failure occurs in the sliding parts of the drive shaft (80) and the bearings (79, 69, 93).

[0031] In a thirteenth aspect, in the compressor system of the tenth aspect, the oil reservoir (95) is formed at a bottom of the compressor (50) so that a pressure of a high-pressure discharge gas discharged from the compression chamber (61) acts on the oil reservoir (95). The compressor (50) includes a first oil supply passage (88) that guides the lubricating oil in the oil reservoir (95) to sliding portions of the drive shaft (80) and the bearings (79, 69, 93) and a second oil supply passage (89) that guides the lubricating oil in the oil reservoir (95) to the compression section (60). A first oil reservoir (96) in which an inlet (88a) of the first oil supply passage (88) is disposed in the oil reservoir (95). and a second oil reservoir (97) in which an inlet (89a) of the second oil supply passage (89) is disposed, and the inlet (88a) of the first oil supply passage (88) and the inlet (89a) of the second oil supply passage (89) are disposed at a height such that, when the oil level of the lubricating oil in the oil reservoir (95) falls below an upper end of the partition member (98), the oil level of the lubricating oil in the second oil reservoir (97) falls below the inlet (89a) of the second oil supply passage (89) before the oil level of the lubricating oil in the first oil reservoir (96) falls below the inlet (88a) of the first oil supply passage (88).

[0032] According to the compressor system of the thirteenth aspect, by simply improving the oil supply passage (87) and the oil reservoir (95), it is possible to easily configure a compressor (50) in which, when the amount of lubricating oil in the oil reservoir (95) decreases, a sealing failure due to a decrease in the amount of lubricating oil sealing the compression chamber (61) occurs before a lubrication failure occurs in the sliding parts of the drive shaft (80) and the bearings (79, 69, 93).

[0033] In a fourteenth aspect, in the compressor system of the tenth aspect, the compressor (50) includes an oil supply passage (87) that guides lubricating oil from the oil reservoir (95) to the compression section (60) and sliding portions of the drive shaft (80) and the bearings (79, 69, 93). The compressor (50) is configured to have residual oil sliding characteristics such that the time from when the oil supply passage (87) stops supplying lubricating oil to the sliding portions of the drive shaft (80) and the bearings (79, 69, 93) to when the bearings (79, 69, 93) and the drive shaft (80) start to be damaged is longer than the time from when the oil supply passage (87) stops supplying lubricating oil to the compression section (60) to when the compression chamber (61) is no longer sealed by the lubricating oil.

[0034] According to the compressor system of the fourteenth aspect, after a decrease in the amount of oil in the oil reservoir (95) occurs, symptoms of failure of the drive shaft (80) and the bearings (79, 69, 93) can be detected before the drive shaft (80) and the bearings (79, 69, 93) are severely damaged due to insufficient lubrication.

[0035] A fifteenth aspect of the present invention relates to a compressor (50) including: a motor (55); a compression section (60) having a compression chamber (61) that draws in and compresses a fluid; a drive shaft (80) connected to the motor (55) and driving the compression section (60); and bearings (79, 69, 93) that support the drive shaft (80); The compressor system includes a prediction device (21) that predicts failures of the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50), wherein the sliding parts of the bearings (79, 69, 93) and the drive shaft (80) are each made of a metallic material, and the prediction device (21) includes a failure prediction unit (23) that predicts failures of the bearings (79, 69, 93) and the drive shaft (80) based on a change in an index indicating the driving state of the motor (55).

[0036] According to the compressor system of the fifteenth aspect, after the bearings (79, 69, 93) and the drive shaft (80) start to deteriorate, symptoms of failure in the bearings (79, 69, 93) and the drive shaft (80) can be easily detected before they are significantly damaged. Note that deterioration of the bearings (79, 69, 93) and the drive shaft (80) refers to a state in which the bearings (79, 69, 93) and the drive shaft (80) are slightly worn or slightly damaged but not yet in a state in which their functionality is reduced (damaged).

[0037] A sixteenth aspect is a compressor system including: a compressor (50) including a motor (55); a compression section (60) having a compression chamber (61) that draws in and compresses a fluid; a drive shaft (80) connected to the motor (55) to drive the compression section (60); and a bearing (79, 69, 93) supporting the drive shaft (80); and a prediction device (21) that predicts failures of the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50), The sliding portion of the bearing (79, 69, 93) that slides against the drive shaft (80) is made of a resin material and has a protrusion that protrudes toward the drive shaft (80), and the prediction device (21) is characterized by comprising a failure prediction unit (23) that predicts failures in the bearing (79, 69, 93) and the drive shaft (80) based on a change in an index that indicates the driving state of the motor (55), which changes in conjunction with the contact of the protrusion with the drive shaft (80).

[0038] According to the compressor system of the sixteenth aspect, symptoms of failure in the bearings (79, 69, 93) and the drive shaft (80) can be easily detected before the oil film condition of the bearings (79, 69, 93) and the drive shaft (80) deteriorates and becomes significantly damaged.

[0039] A seventeenth aspect is a compressor system including a compressor (50) and a prediction device (21) for predicting a failure of a target part of the compressor (50). The compressor (50) includes a motor (55), a compression section (60) having a compression chamber (61) for sucking in and compressing a fluid, a drive shaft (80) connected to the motor (55) for driving the compression section (60), bearings (79, 69, 93) for supporting the drive shaft (80), and a pressure sensor (110) for detecting a failure of the compression section (60) and the drive shaft (80). the compressor mechanism part (100) including an oil supply passage (87) for introducing lubricating oil to the sliding parts of the bearings (79, 69, 93) and the bearings (79, 69, 93); and an indication part provided in the compressor mechanism part (100) for changing a predetermined index in response to a state change in the compressor (50) which is a cause of a failure of the target part, and the prediction device (21) is characterized by comprising a failure prediction part (23) for predicting a failure of the target part based on the change in the predetermined index.

[0040] Here, the failure of the target part of the compressor (50) refers to a state in which the target part of the compressor (50) is inoperable. Moreover, the damage of the target part of the compressor (50) refers to a state in which the target part of the compressor (50) is not inoperable (broken down) but is severely worn or severely damaged, resulting in a decrease in functionality. Moreover, the deterioration of the target part of the compressor (50) refers to a state in which the target part of the compressor (50) is slightly worn or damaged, but not to a state in which the functionality of the target part of the compressor (50) is decreased (damaged).

[0041] Furthermore, the change in the above-mentioned predetermined indicator would not occur without the manifesting section, or would occur at an earlier timing than would occur without the manifesting section.

[0042] In the compressor system of the seventeenth aspect, the compressor (50) is provided with an indication unit that changes a predetermined index in conjunction with a state change in the compressor (50) that is a cause of failure of the target part, and a failure of the target part is predicted based on the change in the predetermined index. Therefore, according to the compressor system, after the occurrence of a state change in the compressor (50) that is a cause of failure of the target part of the compressor (50), a symptom of failure of the target part can be detected before the target part is significantly damaged.

[0043] An 18th aspect is a compressor system according to the 17th aspect, characterized in that the target part is at least one of the compression section (60), the drive shaft (80), and the bearings (79, 69, 93), the manifestation section changes the state of a non-target part different from the target part prior to the change in state of the target part in response to a change in state within the compressor (50) that is a cause of a failure of the target part, and the predetermined indicator changes in response to the change in state of the non-target part.

[0044] According to the compressor system of the eighteenth aspect, when a condition change occurs in the compressor (50) that is a factor in causing a failure of a target part of the compressor (50), a condition change occurs in a non-target part different from the target part before the condition change occurs in the target part, and a predetermined index changes. Therefore, it is possible to detect signs of failure of the target part before the target part is significantly damaged.

[0045] The 19th aspect is directed to a refrigeration device, which includes a compressor system (40) according to any one of the first to 18th aspects, and a refrigerant circuit (30) to which the compressor (50) of the compressor system (40) is connected and which circulates a refrigerant to perform a refrigeration cycle.

[0046] According to the refrigeration apparatus of the 19th aspect, since the refrigeration apparatus is equipped with the compressor system (40), it is possible to detect signs of failure of the target parts of the compressor (50) (at least one of the bearings (79, 69, 93), the drive shaft (80), and the compression section (60)) before the target parts are significantly damaged. [Brief description of the drawings]

[0047] [Figure 1] FIG. 1 is a piping diagram showing a schematic configuration of an air conditioner according to a first embodiment. [Diagram 2] FIG. 2 is a schematic configuration diagram showing the compressor system of the first embodiment and a power supply system to the compressor. [Diagram 3] FIG. 3 is a vertical sectional view of the compressor (scroll compressor) of the first embodiment. [Figure 4] FIG. 4 is a vertical cross-sectional view showing an upper portion of the compressor of the second embodiment. [Diagram 5] FIG. 5 is a PV diagram showing a change in state of the refrigerant in the compression chamber of the compressor of the second embodiment. [Figure 6] FIG. 6 is a schematic configuration diagram showing a compressor system and a power supply system to the compressor according to the fifth embodiment. [Figure 7] FIG. 7 is a piping diagram showing a schematic configuration of an air conditioner according to the sixth embodiment. [Figure 8] FIG. 8 is a schematic configuration diagram showing a compressor system and a power supply system to the compressor according to the seventh embodiment. [Figure 9] FIG. 9 is a graph showing the change over time in the primary component of the driving current of the motor in the compressor of the seventh embodiment. [Figure 10] FIG. 10 is a schematic configuration diagram showing a compressor system and a power supply system to the compressor according to the ninth embodiment. [Figure 11] FIG. 11 is a schematic configuration diagram showing a compressor system according to a second modification of the ninth embodiment and a power supply system to the compressor. [Figure 12] FIG. 12 is a vertical sectional view of a compressor (scroll compressor) of a twelfth embodiment. [Figure 13] FIG. 13 is a vertical sectional view of a compressor (scroll compressor) of the thirteenth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] First Embodiment The air conditioner (10) of the first embodiment is a refrigeration system including a compressor system (40) and a refrigerant circuit (30).

[0049] -Air conditioner- <Overall configuration of the air conditioner> As shown in Fig. 1, the air conditioner (10) includes an outdoor unit (11) and an indoor unit (13). The outdoor unit (11) accommodates an outdoor circuit (31). The indoor unit (13) accommodates an indoor circuit (35). The outdoor circuit (31) and the indoor circuit (35) are connected to each other via a liquid side connecting pipe (37) and a gas side connecting pipe (38) to form a refrigerant circuit (30).

[0050] <Refrigerant circuit> The outdoor circuit (31) includes a compressor (50), a four-way switching valve (32), an outdoor heat exchanger (33), and an expansion valve (34). In the outdoor circuit (31), the compressor (50) has a discharge pipe (53) connected to a first port (P1) of the four-way switching valve (32) and a suction pipe (52) connected to a second port (P2) of the four-way switching valve (32). The outdoor heat exchanger (33) has a gas side end connected to a third port (P3) of the four-way switching valve (32) and a liquid side end connected to one end of the expansion valve (34). The fourth port (P4) of the four-way switching valve (32) is connected to one end of the gas side connection pipe (38). The other end of the expansion valve (34) is connected to one end of the liquid side connection pipe (37).

[0051] The compressor (50) is a hermetic scroll compressor. The compressor (50) constitutes a compressor system (40) together with a main controller (determination device) (21) described later. The compressor (50) will be described in detail later. The outdoor heat exchanger (33) is a heat exchanger that exchanges heat between the refrigerant in the refrigerant circuit (30) and outdoor air. The expansion valve (34) is a so-called electronic expansion valve. The four-way switching valve (32) is a switching valve having four ports (P1 to P4). This four-way switching valve (32) is configured to be switched between a first state (a state shown by a solid line in FIG. 1) in which the first port (P1) communicates with the third port (P3) and the second port (P2) communicates with the fourth port (P4) and a second state (a state shown by a dashed line in FIG. 1) in which the first port (P1) communicates with the fourth port (P4) and the second port (P2) communicates with the third port (P3).

[0052] The outdoor circuit (31) is also provided with a suction pressure sensor (26) and a discharge pressure sensor (27). The suction pressure sensor (26) is connected to a pipe connecting the suction pipe (52) of the compressor (50) and the second port (P2) of the four-way switching valve (32) and detects the pressure of the refrigerant sucked into the compressor (50). The discharge pressure sensor (27) is connected to a pipe connecting the discharge pipe (53) of the compressor (50) and the first port (P1) of the four-way switching valve (32) and detects the pressure of the refrigerant discharged from the compressor (50).

[0053] The indoor circuit (35) is provided with an indoor heat exchanger (36). The indoor circuit (35) has a liquid side end connected to the other end of the liquid side interconnecting pipe (37) and a gas side end connected to the other end of the gas side interconnecting pipe (38). The indoor heat exchanger (36) is a heat exchanger that exchanges heat between the refrigerant in the refrigerant circuit (30) and the indoor air.

[0054] (Outdoor unit, motor drive device) As shown in Fig. 1, the outdoor unit (11) is provided with an outdoor fan (12) and a main controller (21) in addition to the outdoor circuit (31). The outdoor fan (12) is disposed near the outdoor heat exchanger (33) and supplies outdoor air to the outdoor heat exchanger (33). The main controller (21) is configured to control devices provided in the outdoor unit (11). The main controller (21) will be described later.

[0055] As shown in FIG. 2, the outdoor unit (11) is provided with a motor drive device (45). The motor drive device (45) is configured to convert the frequency of an AC current. An input side of the motor drive device (45) is electrically connected to a commercial power source (AC power source) (47), and an output side of the motor drive device (45) is electrically connected to a motor (55) of the compressor (50). The motor drive device (45) has a converter, a DC unit, and an inverter, converts power supplied from the commercial power source (47) into output AC power (three-phase AC power) having a predetermined frequency and voltage, and supplies the output AC power to the motor (55). When the frequency of the output AC power of the motor drive device (45) (hereinafter simply referred to as the “output frequency”) is changed, the rotation speed of the compressor (50) changes, and as a result, the operating capacity of the compressor (50) changes.

[0056] (Indoor unit, remote control) As shown in Fig. 1, the indoor unit includes an indoor fan (14) and a sub-controller (24). The indoor fan (14) is disposed near the indoor heat exchanger (36) and supplies indoor air to the indoor heat exchanger (36). The sub-controller (24) is configured to control devices provided in the indoor unit (13).

[0057] A remote control (15) is communicatively connected to the sub-controller (24). The remote control (15) includes a display unit (16) and operation buttons (17) operated by a user. The display unit (16) is a liquid crystal display unit. Information indicating the operating state of the air conditioner (10) (e.g., the set temperature, etc.) is displayed on the display unit.

[0058] <Air conditioner operation> The air conditioner (10) selectively performs cooling operation and heating operation.

[0059] In the cooling operation, the main controller (21) sets the four-way switching valve (32) to a first state (a state shown by a solid line in FIG. 1 ) and adjusts the operating capacity of the compressor (50) and the opening of the expansion valve (34). The refrigerant discharged from the compressor (50) condenses by dissipating heat to the outdoor air in the outdoor heat exchanger (33) and then expands when passing through the expansion valve (34). The refrigerant that has passed through the expansion valve (34) flows through the liquid side connecting pipe (37) into the indoor circuit (35), and absorbs heat from the indoor air in the indoor heat exchanger (36) and evaporates. The refrigerant then flows through the gas side connecting pipe (38) into the outdoor circuit (31), where it is sucked into the compressor (50) and compressed. The indoor unit (13) blows the air cooled in the indoor heat exchanger (36) into the indoor space.

[0060] In the heating operation, the main controller (21) sets the four-way switching valve (32) to the second state (the state shown by the broken line in FIG. 1 ) and adjusts the operating capacity of the compressor (50) and the opening of the expansion valve (34). The refrigerant discharged from the compressor (50) flows through the gas side connecting pipe (38) into the indoor circuit (35), and condenses in the indoor heat exchanger (36) by dissipating heat to the indoor air. The refrigerant then flows through the liquid side connecting pipe (37) into the outdoor circuit (31), and expands when passing through the expansion valve (34). The refrigerant that has passed through the expansion valve (34) absorbs heat from the outdoor air in the outdoor heat exchanger (33) and evaporates, and is then drawn into the compressor (50) and compressed. The indoor unit (13) blows the air heated in the indoor heat exchanger (36) into the indoor space.

[0061] -Compressor- As shown in Fig. 3, the compressor (50) is a hermetic scroll compressor. The compressor (50) includes a motor (55), a compressor mechanism (100), an upper shaft support (65), a lower shaft support (90), and a casing (51). The motor (55), the compressor mechanism (100), the upper shaft support (65), and the lower shaft support (90) are housed in the casing (51).

[0062] <Casing> The casing (51) is a cylindrical sealed container with closed ends. The axial direction of the casing (51) is the up-down direction. Arranged in the internal space of the casing (51) from top to bottom are a compression section (60), an upper shaft support section (65), a motor (55), and a lower shaft support section (90). An oil reservoir section (95) for storing lubricating oil (refrigeration oil) is formed in the bottom of the casing (51).

[0063] The casing (51) includes a suction pipe (52) and a discharge pipe (53). The suction pipe (52) penetrates the top of the casing (51) and is connected to the compression section (60), and guides low-pressure refrigerant from the refrigerant circuit (30) to the compression section (60). The discharge pipe (53) penetrates the body of the casing (51) and opens into the internal space of the casing (51) (the space below the shaft lower support portion (90)). The discharge pipe (53) guides the high-pressure refrigerant, which has been discharged from the compression chamber (61) and then guided to the space below the shaft lower support portion (90) of the casing (51), to the outside of the compressor (50). With this configuration, the pressure of the high-pressure refrigerant discharged from the compression chamber (61) acts on the space below the shaft lower support portion (90) of the casing (51) (including the oil reservoir portion (95)).

[0064] <Motor> The motor (55) includes a stator (56) and a rotor (57). The stator (56) is fixed to a body portion of the casing (51). The rotor (57) is disposed inside the stator (56). A drive shaft (80) is inserted into the rotor (57).

[0065] <Shaft upper support part> The shaft upper support portion (65) includes a body portion (66) and a main bearing portion (68). The body portion (66) is formed in a thick disk shape and is fixed to the casing (51). A crank chamber (67) is formed in the center of the body portion (66). The crank chamber (67) is a cylindrical recess that opens to the front surface (upper surface in FIG. 1) of the body portion (66). The main bearing portion (68) is formed in a cylindrical shape that protrudes from the rear surface (lower surface in FIG. 1) of the body portion (66) and is disposed in the center of the body portion (66). A through hole for inserting the drive shaft (80) therethrough is formed in the main bearing portion (68). A second bearing (69) described later is fitted into this through hole.

[0066] <Shaft lower support part> The lower shaft support portion (90) includes one sub-bearing portion (91) and three legs (92). The sub-bearing portion (91) is formed in a thick-walled cylindrical shape. A third bearing (93), which will be described later, is fitted into the sub-bearing portion (91). The legs (92) extend radially from the sub-bearing portion (91). The lower shaft support portion (90) has a tip end of each of the legs (92) fixed to a body portion of the casing (51).

[0067] <Compressor mechanism> The compressor mechanism (100) includes a compression section (60), a drive shaft (80), first to third bearings (79, 69, 93), and an oil supply passage (87). Note that various sensors attached to the components of the compressor mechanism (100) are not included in the components of the compressor mechanism (100).

[0068] (Compression section) The compression section (60) is a scroll-type fluid machine. The compression section (60) includes a fixed scroll (70) and an orbiting scroll (75). The wraps of the fixed scroll (70) and the orbiting scroll (75) are meshed with each other to form a plurality of compression chambers (61).

[0069] The fixed scroll (70) includes a fixed end plate (71), a fixed wrap (72), and an outer circumferential wall (73). The fixed end plate (71) is a relatively thick, flat plate-like portion located at the upper portion of the fixed scroll (70). The fixed wrap (72) is formed in a spiral wall shape and protrudes from the front surface (lower surface in FIG. 1 ) of the fixed end plate (71). The outer circumferential wall (73) is formed so as to surround the outer circumferential side of the fixed wrap (72) and protrudes from the front surface of the fixed end plate (71). The outer circumferential wall (73) is fixed to the shaft upper support portion (65) fixed to the casing (51). An intake port (sp) is formed in the outer circumferential wall (73), and the intake pipe (52) is inserted therein. A discharge port (dp) is formed in the fixed end plate portion (71), and a temperature sensor (111) is embedded around the discharge port (dp) to detect the temperature of the discharge gas. The temperature sensor (111) detects the temperature of the discharge gas, converts the detected temperature into an electric signal, and outputs the electric signal to the main controller (21).

[0070] The orbiting scroll (75) includes an orbiting side end plate portion (77), an orbiting side wrap (76), and a boss portion (78). The orbiting side end plate portion (77) is formed in a generally circular flat plate shape. The orbiting side wrap (76) is formed in a spiral wall shape and protrudes from the front surface (upper surface in FIG. 1) of the orbiting side end plate portion (77). The boss portion (78) is formed in a cylindrical shape protruding from the back surface (lower surface in FIG. 1) of the orbiting side end plate portion (77) and is disposed in the center of the orbiting side end plate portion (77). A first bearing (79), which will be described later, is fitted into the boss portion (78).

[0071] (Drive shaft) The drive shaft (80) includes a main shaft portion (81) and an eccentric shaft portion (85). The main shaft portion (81) also includes a main journal portion (82), a sub-journal portion (83), and an intermediate shaft portion (84). The drive shaft (80) is disposed in such a position that the eccentric shaft portion (85) is located above the main shaft portion (81).

[0072] In the main shaft portion (81), a main journal portion (82), an intermediate shaft portion (84), and an auxiliary journal portion (83) are arranged in this order from one end to the other end. The main journal portion (82), the intermediate shaft portion (84), and the auxiliary journal portion (83) are each formed in a cylindrical shape and arranged coaxially with one another. In the main shaft portion (81) of this embodiment, the main journal portion (82) has a larger diameter than the intermediate shaft portion (84), and the auxiliary journal portion (83) has a smaller diameter than the intermediate shaft portion (84). In the main shaft portion (81) of this embodiment, the main journal portion (82) is located on the upper side, and the auxiliary journal portion (83) is located on the lower side.

[0073] The main journal portion (82) is inserted into the inside of a second bearing (69) fitted into the main bearing portion (68) of the upper shaft support portion (65) and is supported by the second bearing (69). The sub-journal portion (83) is inserted into the inside of a third bearing (93) fitted into the sub-bearing portion (91) of the lower shaft support portion (90) and is supported by the third bearing (93). The intermediate shaft portion (84) is inserted into the inside of a rotor (57) of the motor (55) and is fixed to the rotor (57).

[0074] The eccentric shaft portion (85) is formed in a relatively short shaft shape and protrudes from an end face of the main journal portion (82). In the drive shaft (80) of this embodiment, the eccentric shaft portion (85) is located on the upper end side. The axis of the eccentric shaft portion (85) is substantially parallel to the axis of the main shaft portion (81) and is eccentric with respect to the axis of the main shaft portion (81). The eccentric shaft portion (85) is inserted into the inside of a first bearing (79) fitted into the boss portion (78) of the orbiting scroll (75) and is supported by the first bearing (79).

[0075] (Bearings) The first to third bearings (79, 69, 93) are all cylindrically shaped sliding bearings that support the drive shaft (80).

[0076] The first bearing (79) is fitted into the boss portion (78) of the orbiting scroll (75). The eccentric shaft portion (85) of the drive shaft (80) is inserted into the inside of the first bearing (79) to support the eccentric shaft portion (85) of the drive shaft (80).

[0077] The second bearing (69) is fitted into the inside of the main bearing portion (68) of the upper shaft support portion (65). The main journal portion (82) of the drive shaft (80) is inserted into the inside of the second bearing (69), and supports the main journal portion (82) of the drive shaft (80).

[0078] The third bearing (93) is fitted inside the sub-bearing portion (91) of the shaft lower support portion (90). The sub-journal portion (83) of the drive shaft (80) is inserted into the inside of the third bearing (93), and supports the sub-journal portion (83) of the drive shaft (80).

[0079] In the first embodiment, the first to third bearings (79, 69, 93), together with the drive shaft (80), are components whose failures are predicted by a failure prediction unit (23) (to be described later) although details will be described later.

[0080] (Fuel passage) The oil supply passage (87) is a passage for supplying lubricating oil (refrigeration oil) stored in an oil reservoir (95) formed in the bottom of the casing (51) to sliding parts. The oil supply passage (87) has a main oil supply passage (88) and an auxiliary oil supply passage (89).

[0081] The main oil supply passage (88) is formed in the drive shaft (80). The main oil supply passage (88) has a main passage extending in the axial direction from one axial end (the lower end in FIG. 3) to the other axial end (the upper end in FIG. 3) of the drive shaft (80), and branch passages branching from the main passage toward a sliding portion between the drive shaft (80) and the second bearing (69), a sliding portion between the drive shaft (80) and the third bearing (93), and a sliding portion between the drive shaft (80) and the first bearing (79). The main oil supply passage (88) guides lubricating oil (refrigeration oil) stored in an oil reservoir (95) to each of the sliding portions between the drive shaft (80) and the first to third bearings (79, 69, 93). In other words, the main oil supply passage (88) is an oil supply passage that guides the lubricating oil in the oil reservoir (95) to the drive shaft (80) and the sliding portions of the bearings (79, 69, 93).

[0082] The auxiliary oil supply passage (89) is formed to extend between the shaft upper support portion (65) and the fixed scroll (70) and guides the lubricating oil stored in the crank chamber (67) to the compression portion (60) (the gap between the fixed scroll (70) and the orbiting scroll (75)). The auxiliary oil supply passage (89) is formed so that one end opens in the crank chamber (67) and the other end opens in the gap between the outer circumferential wall portion (73) of the fixed scroll (70) and the orbiting-side end plate portion (77) of the orbiting scroll (75). The lubricating oil that flows out from the oil reservoir portion (95) through the main oil supply passage (88) and has been guided to the sliding portions between the drive shaft (80) and the first bearing (79) to lubricate the sliding portions is stored in the crank chamber (67). Therefore, the auxiliary oil supply passage (89) guides the lubricating oil, which has lubricated the sliding parts of the drive shaft (80) and the first bearing (79), from the crank chamber (67) to the compression section (60). The lubricating oil guided to the compression section (60) seals the gap between the fixed scroll (70) and the orbiting scroll (75) (seals the compression chamber (61)). In other words, the auxiliary oil supply passage (89) is an oil supply passage that guides the lubricating oil in the oil reservoir (95) to the compression section (60), and also guides the lubricating oil that is supplied from the oil reservoir (95) to the sliding parts of the drive shaft (80) and the first bearing (79) via the main oil supply passage (88) and flows out into the crank chamber (67) to the compression section (60).

[0083] With this configuration, in the first embodiment, first, the lubricating oil in the oil reservoir (95) on which the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) acts is distributed and supplied to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) via the main oil supply passage (88). Then, the lubricating oil remaining after lubricating the sliding parts of the drive shaft (80) and the first bearing (79) is stored in the crank chamber (67). The lubricating oil stored in the crank chamber (67) is supplied to the compression section (60) (the gap between the fixed scroll (70) and the orbiting scroll (75)) via the auxiliary oil supply passage (89). In other words, in the first embodiment, the oil supply passage (87) is configured to supply the lubricating oil in the oil reservoir (95) to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) before the compression section (60). With this configuration, in the compressor (50), when the amount of lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of lubricating oil sealing the compression chamber (61) occurs earlier than poor lubrication of the sliding parts of the drive shaft (80) and the first, second, and third bearings (79, 69, 93).

[0084] -Control System- In the air conditioner (10) of the present embodiment, a main controller (21) of the outdoor unit (11) and a sub-controller (24) of the indoor unit (13) are connected to each other by wiring to form a control system (20).

[0085] Although not shown, each of the main controller (21) and the sub-controller (24) includes a CPU that executes a control program, and a memory that stores the control program and data necessary for executing the control program, etc.

[0086] As described above, the main controller (21) is configured to control the devices provided in the outdoor unit (11). For example, the main controller (21) adjusts the rotation speed of the outdoor fan (12) and the opening of the expansion valve (34), and also operates the four-way switching valve (32). As shown in Fig. 2, the main controller (21) also includes a capacity control unit (22) and a failure prediction unit (23). The capacity control unit (22) and the failure prediction unit (23) will be described later.

[0087] As described above, the sub-controller (24) is configured to control the devices provided in the indoor unit (13). For example, the sub-controller (24) adjusts the rotation speed of the outdoor fan (12) and the opening of the expansion valve (34), and operates the four-way switching valve (32). The sub-controller (24) also adjusts the rotation speed of the indoor fan (14).

[0088] -Ability Control Unit- The capacity control section (22) is configured to adjust the operating capacity of the compressor (50) so that the air conditioner (10) exerts an air conditioning capacity commensurate with the air conditioning load of the indoor space.

[0089] When the air conditioning capacity of the air conditioner (10) is insufficient for the air conditioning load of the indoor space, the capacity control unit (22) outputs a command signal to the motor drive device (45) to increase the output frequency of the motor drive device (45). When the output frequency of the motor drive device (45) increases, the rotation speed of the compressor (50) increases. As a result, the operating capacity of the compressor (50) increases, and the air conditioning capacity of the air conditioner (10) increases.

[0090] In cooling operation, for example, when the detection value of the suction pressure sensor (26) exceeds the low pressure target value of the refrigeration cycle, the capacity control unit (22) determines that the air conditioning capacity of the air conditioner (10) is insufficient for the air conditioning load of the indoor space. On the other hand, in heating operation, for example, when the detection value of the discharge pressure sensor (27) is below the high pressure target value of the refrigeration cycle, the capacity control unit (22) determines that the air conditioning capacity of the air conditioner (10) is insufficient for the air conditioning load of the indoor space.

[0091] When the air conditioning capacity of the air conditioner (10) is excessive relative to the air conditioning load of the indoor space, the capacity control unit (22) outputs a command signal to the motor drive device (45) to lower the output frequency of the motor drive device (45). When the output frequency of the motor drive device (45) decreases, the rotation speed of the compressor (50) decreases. As a result, the operating capacity of the compressor (50) decreases, and the air conditioning capacity of the air conditioner (10) decreases.

[0092] In cooling operation, for example, when the detection value of the suction pressure sensor (26) is below the low pressure target value of the refrigeration cycle, the capacity control unit (22) determines that the air conditioning capacity of the air conditioner (10) is excessive for the air conditioning load of the indoor space. On the other hand, in heating operation, for example, when the detection value of the discharge pressure sensor (27) is above the high pressure target value of the refrigeration cycle, the capacity control unit (22) determines that the air conditioning capacity of the air conditioner (10) is excessive for the air conditioning load of the indoor space.

[0093] -Prediction Department- The failure prediction unit (23) is configured to detect symptoms of failure in the drive shaft (80) and the first to third bearings (79, 69, 93) based on a detection value (i.e., the temperature Tdp of the discharge gas) of the temperature sensor (111) embedded in the compression section (60) and predict failure. Specifically, the failure prediction unit (23) repeatedly performs a determination operation for determining whether a predictive condition is met at predetermined time intervals (e.g., every 30 seconds). The predictive condition is a condition indicating that there is a predictive condition of failure in the drive shaft (80) and the first to third bearings (79, 69, 93). When the predictive condition is met, the failure prediction unit (23) performs an avoidance operation for avoiding failure in the drive shaft (80) and the first to third bearings (79, 69, 93).

[0094] <Judgment operation> The following describes the determination operation of the failure prediction unit (23). In the failure prediction unit (23) of the present embodiment, the prediction condition is that the temperature difference ΔTdp (Tdp-Tn) between the discharge gas temperature Tdp (the value detected by the temperature sensor (111)) and a predetermined normal value Tn is equal to or greater than a reference value Tb (ΔTdp≧Tb).

[0095] First, the failure prediction unit (23) calculates a temperature difference ΔTdp between the discharge gas temperature Tdp and a predetermined normal value Tn. The normal value Tn is the discharge gas temperature in a normal state where the sliding parts of the compressor (50) are not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value Tn. The failure prediction unit (23) calculates the temperature difference ΔTdp by subtracting the normal value Tn from the discharge gas temperature Tdp. The normal value Tn may be a value determined in advance for each type of compressor (50). Alternatively, after the compressor system (40) is installed, a test run may be performed to measure the discharge gas temperature in a normal state where the sliding parts of the compressor (50) are not insufficiently lubricated, and the measured value may be set as the normal value Tn. The normal value Tn is determined for each operating condition of the compressor (50), which is the rotation speed, high pressure, and low pressure.

[0096] Next, the failure prediction unit (23) compares the calculated temperature difference ΔTdp with a judgment reference value Tb. The failure prediction unit (23) stores a reference value as the judgment reference value Tb. The failure prediction unit (23) determines that the predictive condition is met when the temperature difference ΔTdp is equal to or greater than the judgment reference value Tb (ΔTdp≧Tb). In other words, the failure prediction unit (23) of the present embodiment determines that the predictive condition is met when the temperature difference ΔTdp becomes equal to or greater than the judgment reference value Tb for the first time.

[0097] As described above, the main controller (prediction device) (21) of the present embodiment includes a failure prediction unit (23) that determines whether or not a predetermined predictive condition indicating the presence of a predictive failure of the drive shaft (80) and the first to third bearings (79, 69, 93) is satisfied. The failure prediction unit (23) measures the discharge gas temperature Tdp and determines whether or not the predictive condition is satisfied (whether or not there is a predictive failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the discharge gas temperature Tdp. Note that in the present embodiment 1, the discharge gas temperature Tdp (an index indicating the operating state of the compression section (60)) is used as the predictive condition for the following reasons.

[0098] In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubrication state of each sliding part of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) changes from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) come into contact with each other and wear, and eventually the drive shaft (80) and the first to third bearings (79, 69, 93) break down (become inoperable) due to seizure or the like. Meanwhile, in the compression section (60), the amount of lubricating oil sealing the compression chamber (61) decreases before the lubrication state of each sliding part changes from fluid lubrication to mixed lubrication or boundary lubrication. When the amount of lubricating oil sealing the compression chamber (61) decreases, the amount of heat transferred from the refrigerant to the lubricating oil decreases. In addition, the leaked refrigerant is recompressed, so that the temperature of the discharged refrigerant increases compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without poor lubrication), and the discharge gas temperature Tdp also increases compared to the normal state. Therefore, in the first embodiment, attention is focused on the discharge gas temperature Tdp, which rises in conjunction with a sealing failure caused by a decrease in the amount of lubricating oil sealing the compression chamber (61), and the discharge gas temperature Tdp is used to determine whether or not there are signs of failure in the drive shaft (80) and the first to third bearings (79, 69, 93).By doing so, it is possible to detect signs of failure in the drive shaft (80) and the first to third bearings (79, 69, 93) after a decrease in the amount of oil in the oil reservoir (95), which may cause a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

[0099] In particular, in the first embodiment, the compressor (50) is configured such that, when the amount of lubricating oil in the oil reservoir (95) decreases, a sealing failure due to a decrease in the amount of lubricating oil sealing the compression chambers (61) occurs before a lubrication failure occurs in the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93). Specifically, the oil supply passage (87) is configured to distribute and supply the lubricating oil in the oil reservoir (95) to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) before a lubrication failure occurs in the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93), and to supply the remaining lubricating oil accumulated in the crank chamber (67) to the compression part (60). Therefore, before a lubrication failure occurs in the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93), a sealing failure occurs due to a decrease in the amount of lubricating oil sealing the compression chambers (61), and the discharge gas temperature Tdp increases. Therefore, with this configuration, the failure prediction unit (23) can detect signs of failure in the drive shaft (80) and the first, second, and third bearings (79, 69, 93) before poor lubrication occurs in the sliding portions of the drive shaft (80) and the first, second, and third bearings (79, 69, 93), thereby making it possible to reliably predict failure at an early stage.

[0100] In the first embodiment, the oil supply passage (87) serves as an indication part that, in response to a condition change in the compressor (50) (a reduction in the amount of lubricating oil in the oil reservoir (95)) that is a cause of failure in the drive shaft (80) and the first to third bearings (79, 69, 93), which are target parts for failure prediction, changes the state of a non-target part that is different from the target part (a reduction in the amount of lubricating oil sealing the compression chamber (61)) prior to the change in the condition of the target part (poor lubrication of the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93)).

[0101] Evasion Movement When the predictive condition is satisfied, the failure prediction unit (23) performs an avoidance operation for preventing failure of the drive shaft (80) and the first, second, and third bearings (79, 69, 93). The avoidance operation is an operation that needs to be performed when there is a predictive failure of the drive shaft (80) and the first, second, and third bearings (79, 69, 93) (when there is a possibility of failure).

[0102] The failure prediction unit (23) changes the operating state of the compressor (50) from a normal state to a light load state as an avoidance operation. The failure prediction unit (23) performs this operation every time a predictive condition is satisfied.

[0103] The normal state is an operating state of the compressor (50) when the predictive condition is not satisfied. In the normal state, the rotation speed of the compressor (50) is a value set by the capacity control unit (22). On the other hand, the light load state is an operating state of the compressor (50) in which the load acting on the drive shaft (80) and the first to third bearings (79, 69, 93) is smaller than that at the time when the predictive condition is satisfied. In the present embodiment, the light load state is an operating state in which the rotation speed of the compressor (50) is lower than that at the time when the predictive condition is satisfied.

[0104] Therefore, the failure prediction unit (23) executes, as a avoidance action, an action of lowering the rotation speed of the compressor (50) below the value at the time of executing the judgment operation (specifically, an action of lowering the output frequency of the motor drive device (45) below the value set by the capacity control unit (22) at the time of executing the judgment operation).

[0105] After the operating state of the compressor (50) is changed from the normal state to the light-load state, the failure prediction unit (23) measures the duration of the light-load state. During the duration of the light-load state, the lubricating oil that has been accumulating in the heat exchangers (33, 36) of the refrigerant circuit (30) and the like may return to the compressor (50) together with the refrigerant, making it possible to ensure the amount of oil supplied to the drive shaft (80) and the first, second, and third bearings (79, 69, 93).

[0106] Therefore, when the duration of the light load state reaches a predetermined reference time, the failure prediction unit (23) changes the operating state of the compressor (50) from the light load state to the normal state. In this case, the failure prediction unit (23) changes the operating capacity of the compressor (50) (specifically, the output frequency of the motor drive device (45)) back to the value immediately before the operating state of the compressor (50) changed to the light load state.

[0107] Furthermore, the failure prediction unit (23) of the present embodiment performs, as an avoidance operation, an operation of issuing a warning that there is a sign of a failure in the drive shaft (80) and the first to third bearings (79, 69, 93). The failure prediction unit (23) performs this operation when a sign condition is satisfied.

[0108] Specifically, the failure prediction unit (23) displays, on the display unit (16) of the remote control (15), a display indicating that there is a sign of failure in the drive shaft (80) and the first to third bearings (79, 69, 93). The display may be text information such as “There may be an abnormality in the compressor” or an error code indicating that there is a sign of failure in the drive shaft (80) and the first to third bearings (79, 69, 93). The display may be a notification to prompt an action such as repair or part replacement. The failure prediction unit (23) may notify an outside party (such as an administrator or a management server that takes action such as repair or part replacement) that there is a sign of failure in the drive shaft (80) and the first to third bearings (79, 69, 93). The notification may be made together with the display on the display unit (16) of the remote control (15) or instead of the display on the display unit (16) of the remote control (15).

[0109] -Effects of embodiment 1- The compressor system (40) of this embodiment includes a compressor (50) and a main controller (21) (prediction device) that detects symptoms of failure in a drive shaft (80) and first to third bearings (79, 69, 93) (target parts) of the compressor (50) and predicts failure. The compressor (50) includes a motor (55), a compressor mechanism (100), and an oil supply passage (87) (manifestation part) that is provided in the compressor mechanism (100) and changes a discharge gas temperature Tdp (a predetermined index) in response to a change in condition in the compressor (50) (a reduction in the amount of lubricating oil in the oil reservoir (95)) that is a cause of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) (target parts). The prediction device (21) also includes a failure prediction unit (23) that detects symptoms of failure in the drive shaft (80) and the first to third bearings (79, 69, 93) (target parts) based on a change in the discharge gas temperature Tdp (predetermined index) and predicts failure.

[0110] Here, the failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50) refers to a state in which the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50) become inoperable due to seizure or the like.

[0111] In the compressor system (40) of this embodiment, the oil supply passage (87) is configured so that the discharge gas temperature Tdp changes in conjunction with a decrease in the amount of lubricating oil in the oil reservoir (95), which is a factor in causing failures in the drive shaft (80) and the first to third bearings (79, 69, 93), and failures are predicted by detecting symptoms of failures in the drive shaft (80) and the first to third bearings (79, 69, 93) based on the change in the discharge gas temperature Tdp. Therefore, according to the compressor system (40), after a decrease in the amount of lubricating oil in the oil reservoir (95) occurs, symptoms of failures in the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected at an early stage, and failures can be predicted.

[0112] As described above, in the compressor system (40) of the present embodiment, the oil supply passage (87) is configured to distribute and supply the lubricating oil in the oil reservoir (95) to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) prior to the compression section (60), and to supply the remaining lubricating oil accumulated in the crank chamber (67) to the compression section (60). Therefore, in the compressor (50), when the amount of lubricating oil in the oil reservoir (95) decreases (a change in state in the compressor (50) that causes a failure of the target part occurs), the amount of lubricating oil sealing the compression chamber (61) (state of a non-target part different from the target part) decreases before the drive shaft (80) and the first to third bearings (79, 69, 93) deteriorate due to a lack of lubricating oil (a change in state of the target part) and various indices (for example, discharge gas temperature Tdp) indicating the operating state of the compression section (60) change.

[0113] In view of this, in the compressor system (40) of the present embodiment, when the amount of lubricating oil in the oil reservoir (95) decreases, the amount of lubricating oil sealing the compression chambers (61) (sealing oil amount) decreases and various indicators indicating the operating state of the compression section (60) change, and the various indicators indicating the operating state of the compression section (60) are used to predict failures of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, according to the compressor system (40) of the present embodiment, after the amount of lubricating oil in the oil reservoir (95) decreases, symptoms of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected and failures can be predicted before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

[0114] In addition, in the compressor system (40) of the present embodiment, the temperature of the discharge gas from the compression mechanism (60) (discharge gas temperature Tdp) is used as an index showing the operating state of the compression section (60), which changes in conjunction with the amount of lubricating oil sealing the compression chamber (61), for predicting failures of the drive shaft (80) and the first to third bearings (79, 69, 93).

[0115] When the amount of lubricating oil sealing the compression chamber (61) decreases, the amount of heat transferred from the refrigerant (fluid) to the lubricating oil decreases, and the leaked refrigerant is recompressed, causing the temperature of the discharged refrigerant to increase, and the discharge gas temperature Tdp also increases. Therefore, according to the compressor system (40), by using the discharge gas temperature Tdp to predict failures of the drive shaft (80) and the first to third bearings (79, 69, 93), it is possible to detect symptoms of failures in the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50) and to predict failures before the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50) are significantly damaged. Furthermore, according to the compressor system, instead of detecting a decrease in the amount of seal oil, which is difficult to detect, signs of malfunction in the drive shaft (80) and the first, second, and third bearings (79, 69, 93) of the compressor (50) are detected by detecting the temperature of the discharge gas, which changes in conjunction with a change in the amount of seal oil. This makes it easy to predict malfunctions.

[0116] The discharge gas temperature Tdp changes in accordance with a change in the amount of seal oil in the compression chamber (61), but is not affected by friction between the drive shaft (55) and the first to third bearings (79, 69, 93). Therefore, the discharge gas temperature Tdp can easily detect a deterioration in the sealing performance of the compression chamber (61), and detecting the discharge gas temperature Tdp as an index of the deterioration in the sealing performance of the compression chamber (61) improves the accuracy of prediction.

[0117] In addition, in the compressor system (40) of the present embodiment, the oil supply passage (87) is configured to distribute and supply the lubricating oil in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) prior to the compression section (60), and to supply the remaining lubricating oil accumulated in the crank chamber (67) to the compression section (60). Therefore, in the compressor system (40), lubricating oil is supplied from the oil reservoir (95) of the compressor (50) to the compression section (60) and the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93). When the amount of lubricating oil in the oil reservoir (95) decreases, a sealing failure due to a decrease in the amount of lubricating oil sealing the compression chamber (61) occurs earlier than a lubrication failure of the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93), and various indicators showing the operating state of the compression section (60) change.

[0118] In the compressor system (40) of the present embodiment, the discharge gas temperature Tdp, which increases in association with poor sealing caused by a decrease in the amount of lubricating oil sealing the compression chambers (61), is used to predict failures in the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, according to the compressor system (40) of the present embodiment, after a decrease in the amount of oil in the oil reservoir (95) occurs, symptoms of failure in the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected and failures can be predicted before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged due to poor lubrication.

[0119] The air conditioner (refrigeration unit) (10) of this embodiment includes the compressor system (40) and a refrigerant circuit (30) to which the compressor (50) of the compressor system (40) is connected and which circulates refrigerant to perform a refrigeration cycle.

[0120] According to the air conditioner (refrigeration unit) (10) of the present embodiment, since the air conditioner (refrigeration unit) is equipped with the compressor system (40), symptoms of a malfunction of the drive shaft (80) and the first, second, and third bearings (79, 69, 93) of the compressor (50) can be detected at an early stage, and the malfunction can be predicted.

[0121] In the first embodiment, the discharge gas temperature Tdp is acquired by the temperature sensor (111) embedded around the discharge port (dp). However, the discharge gas temperature Tdp may be acquired by a temperature sensor provided on the outer surface of the casing (51) of the compressor (50). If the temperature sensor for measuring the discharge gas temperature Tdp is located away from the discharge port (dp) of the compressor (50), the temperature sensor is easily affected by other components and lubricating oil, making it difficult to detect the change in the discharge gas temperature Tdp due to recompression, and the prediction accuracy is reduced. Therefore, the temperature sensor (111) embedded around the discharge port (dp) as in the first embodiment is most preferable for improving the prediction accuracy, since it can sensitively detect the change in the discharge gas temperature Tdp due to recompression. Even when the temperature sensor is provided on the outer surface of the casing (51) of the compressor (50), the prediction accuracy can be improved by providing the temperature sensor in a position close to the discharge port (dp), as in the first embodiment.

[0122] Second Embodiment The air conditioner (10) of the second embodiment is the same as the air conditioner (10) of the first embodiment, except that a pressure sensor (112) that detects the internal pressure of the compression chamber (61) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation by the failure prediction unit (23) is changed. The other configurations and operations are the same as those of the first embodiment. Here, the differences from the first embodiment will be described.

[0123] <Pressure Sensor> As shown in Fig. 4, the pressure sensor (112) is embedded in the compression section (60) so as to be able to detect the internal pressure of the compression chamber (61) of the compressor (50). A plurality of pressure sensors (112) are provided so as to be able to detect the internal pressure of the compression chamber (61) from the start of suction to the end of discharge. The pressure sensor (112) detects the internal pressure of the compression chamber (61), converts the detected internal pressure into an electric signal, and outputs the electric signal to the main controller (21).

[0124] <Judgment operation> The determination operation of the failure prediction unit (23) will be described. In the present embodiment, the failure prediction unit (23) also repeatedly performs a determination operation for determining whether a predictive condition is satisfied at predetermined time intervals (e.g., every 30 seconds). In the present embodiment, the predictive condition is that an increase ΔW (W-Wn) in the compression chamber workload W of the compressor (50) from a predetermined normal value Wn is equal to or greater than a determination reference value Wb (ΔW≧Wb).

[0125] First, the failure prediction unit (23) calculates the workload of the compression chamber (compression chamber workload W) while each of the suction, compression, and discharge processes is being performed in the compressor (50). As shown in Fig. 5, the failure prediction unit (23) calculates the compression chamber workload W of the compressor (50) by integrating the volume V of the compression chamber (61) by the internal pressure P of the compression chamber (61) (the value detected by the pressure sensor (112)).

[0126] Next, the failure prediction unit (23) calculates an increase ΔW of the compression chamber work W of the compressor (50) relative to a predetermined normal value Wn. The normal value Wn is the compression chamber work W of the compressor (50) in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value Wn. The failure prediction unit (23) calculates the increase ΔW by subtracting the normal value Wn from the compression chamber work W of the compressor (50). The normal value Wn may be a value determined in advance for each type of compressor (50). Alternatively, after the compressor system (40) is installed, a test run may be performed to calculate the compression chamber work W of the compressor (50) in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated, and the calculated value may be the normal value Wn. The normal value Wn is determined for each operating condition of the compressor (50), which is the rotation speed, high pressure, and low pressure.

[0127] Next, the failure prediction unit (23) compares the calculated increase amount ΔW with a judgment reference value Wb. The failure prediction unit (23) stores a reference value as the judgment reference value Wb. The failure prediction unit (23) determines that the predictive condition is established when the increase amount ΔW is equal to or greater than the judgment reference value Wb (ΔW≧Wb). In other words, the failure prediction unit (23) of the present embodiment determines that the predictive condition is established when the increase amount ΔW becomes equal to or greater than the judgment reference value Wb for the first time.

[0128] As described above, in the second embodiment, the failure prediction section (23) calculates the compression chamber work load W of the compressor (50) and determines whether or not a predictive condition is satisfied (whether or not there are predictive signs of failure in the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the compression chamber work load W of the compressor (50). Note that in the second embodiment, the compression chamber work load W of the compressor (50) (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of lubricating oil sealing the compression chamber (61), is used as the predictive condition for the following reasons.

[0129] In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubrication state of each sliding part of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) changes from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) come into contact with each other and wear, and eventually the drive shaft (80) and the first to third bearings (79, 69, 93) break down (become inoperable) due to seizure or the like. Meanwhile, in the compression section (60), the amount of lubricating oil sealing the compression chamber (61) decreases before the lubrication state of each sliding part changes from fluid lubrication to mixed lubrication or boundary lubrication. When the amount of lubricating oil sealing the compression chamber (61) decreases, the sealing performance of the compression chamber (61) decreases, and a refrigerant leak occurs, in which the refrigerant leaks from the compression chamber (61) with a higher internal pressure to the compression chamber (61) with a lower internal pressure. When a refrigerant leak occurs, as shown in Fig. 5, the amount of work increases in the compression chamber (61) into which the refrigerant leaks and the amount of work decreases in the compression chamber (61) from which the refrigerant leaks, but the compression chamber work W for one cycle increases compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without poor lubrication). Therefore, in the second embodiment, attention is focused on the compression chamber work W of the compressor (50), which increases in conjunction with a sealing failure caused by a decrease in the amount of lubricating oil sealing the compression chamber (61), and the compression chamber work W of the compressor (50) is used to determine whether or not there are signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93).By doing so, after a decrease in the amount of oil in the oil reservoir (95) occurs, which may cause a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged, signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected and a malfunction can be predicted.

[0130] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the second embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment.

[0131] -Modification 1 of embodiment 2- Modification 1 is an embodiment in which the predictive condition is changed from that of embodiment 2. In Modification 1, the predictive condition is that the increase rate Wr ((W-Wn) / Wn) of the compression chamber work load W of the compressor (50) relative to a predetermined normal value Wn is equal to or greater than a reference value Wb (for example, 0.1 (10%)) (Wr≧Wb).

[0132] The failure prediction unit (23) obtains the compression chamber workload W of the compressor (50) in the same manner as in the second embodiment, and then calculates an increase rate Wr of the compression chamber workload W of the compressor (50) relative to a predetermined normal value Wn. The failure prediction unit (23) calculates the increase rate Wr by subtracting the normal value Wn from the compression chamber workload W of the compressor (50) and dividing the result by the normal value Wn. The failure prediction unit (23) then compares the calculated increase rate Wr with a judgment reference value Wb, and determines that a predictive condition is established when the increase rate Wr is equal to or greater than the judgment reference value Wb (Wr≧Wb).

[0133] As described above, in the judgment operation, even if the object to be compared with the judgment reference value Wb is the increase rate Wr ((W-Wn) / Wn) of the compression chamber work W of the compressor (50) relative to a predetermined normal value Wn, the same effect as in embodiment 2 can be achieved.

[0134] Third Embodiment The air conditioner (10) of the third embodiment is the same as the air conditioner (10) of the first embodiment, except that a pressure sensor (112) that detects the internal pressure of the compression chamber (61) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation by the failure prediction unit (23) is changed. The other configurations and operations are the same as those of the first embodiment. Here, the differences from the first embodiment will be described.

[0135] <Pressure Sensor> As shown in Fig. 4, the pressure sensor (112) is embedded in the compression section (60) so as to be able to detect the internal pressure of the compression chamber (61) of the compressor (50). A plurality of pressure sensors (112) are provided so as to be able to detect the internal pressure of the compression chamber (61) from the start of suction to the end of discharge. The pressure sensor (112) detects the internal pressure of the compression chamber (61), converts the detected internal pressure into an electric signal, and outputs the electric signal to the main controller (21).

[0136] <Judgment operation> The determination operation of the failure prediction unit (23) will be described. In the present embodiment, the failure prediction unit (23) also repeatedly performs a determination operation for determining whether a predictive condition is satisfied at predetermined time intervals (e.g., every 30 seconds). In the present embodiment, the predictive condition is that an increase ΔP (P-Pn) in the internal pressure P of the compressor (50) from a predetermined normal value Pn is equal to or greater than a judgment reference value Pb (ΔP≧Pb).

[0137] First, the failure prediction unit (23) calculates an increase ΔP of the internal pressure P of the compressor (50) relative to a predetermined normal value Pn. The normal value Pn is the internal pressure of the compressor (50) in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value Pn. The failure prediction unit (23) calculates the increase ΔP by subtracting the normal value Pn from the internal pressure P of the compressor (50). The normal value Pn may be a value determined in advance for each type of compressor (50). Alternatively, after the compressor system (40) is installed, a test run may be performed to calculate the internal pressure of the compressor (50) in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated, and the calculated value may be set as the normal value Pn. The normal value Pn is determined for each operating condition of the compressor (50), which is the rotation speed, high pressure, and low pressure.

[0138] Next, the failure prediction unit (23) compares the calculated increase amount ΔP with a judgment reference value Pb. The failure prediction unit (23) stores a reference value as the judgment reference value Pb. The failure prediction unit (23) determines that the predictive condition is established when the increase amount ΔP is equal to or greater than the judgment reference value Pb (ΔP≧Pb). In other words, the failure prediction unit (23) of the present embodiment determines that the predictive condition is established when the increase amount ΔP becomes equal to or greater than the judgment reference value Pb for the first time.

[0139] As described above, in the third embodiment, the failure prediction section (23) calculates the internal pressure P of the compressor (50) and determines whether or not a predictive condition is satisfied (whether or not there are predictive signs of failure in the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the internal pressure P of the compressor (50). Note that in the third embodiment, the internal pressure P of the compressor (50) (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of lubricating oil sealing the compression chamber (61), is used as the predictive condition for the following reasons.

[0140] In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubrication state of each sliding part of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) changes from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) come into contact with each other and wear, and eventually the drive shaft (80) and the first to third bearings (79, 69, 93) break down (become inoperable) due to seizure or the like. Meanwhile, in the compression section (60), the amount of lubricating oil sealing the compression chamber (61) decreases before the lubrication state of each sliding part changes from fluid lubrication to mixed lubrication or boundary lubrication. When the amount of lubricating oil sealing the compression chamber (61) decreases, the sealing ability of the compression chamber (61) decreases, causing a refrigerant leak, in which the refrigerant leaks from the compression chamber (61) with a higher internal pressure to the compression chamber (61) with a lower internal pressure. When a refrigerant leak occurs, the internal pressure P in the compression chamber (61) into which the refrigerant has leaked increases compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without poor lubrication), and the internal pressure P in the compression chamber (61) from which the refrigerant has leaked decreases compared to the normal state, as shown in FIG. Therefore, in the third embodiment, attention is focused on the internal pressure P of the compressor (50), which increases or decreases in conjunction with a sealing failure caused by a decrease in the amount of lubricating oil sealing the compression chamber (61), and the internal pressure P of the compressor (50) is used to determine whether or not there are signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93). By doing so, after a decrease in the amount of oil in the oil reservoir (95) occurs, which may cause a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), it is possible to detect signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) and predict the malfunction before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

[0141] In the third embodiment, when the refrigerant leakage occurs, the internal pressure P detected at the timing (rotation angle) when the pressure sensor (112) detects an internal pressure P that is higher than the normal pressure is used in the judgment operation. Therefore, in the judgment operation, the predictive condition is that the increase ΔP (P-Pn) of the internal pressure P of the compressor (50) from a predetermined normal value Pn is equal to or greater than the judgment reference value Pb (ΔP≧Pb). Note that the internal pressure P detected at the timing (rotation angle) when the pressure sensor (112) detects an internal pressure P that is lower than the normal pressure is used in the judgment operation, and the predictive condition in the judgment operation may be that the decrease ΔP (Pn-P) of the internal pressure P of the compressor (50) from a predetermined normal value Pn is equal to or greater than the judgment reference value Pb (ΔP≧Pb).

[0142] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the third embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment. The internal pressure P of the compression chamber (61) changes in accordance with the change in the amount of seal oil in the compression chamber (61), but is not affected by friction between the drive shaft (55) and the first, second and third bearings (79, 69, 93). Therefore, the internal pressure P of the compression chamber (61) can easily detect a deterioration in the sealing performance of the compression chamber (61). By detecting the internal pressure P of the compression chamber (61) as an index of the deterioration in the sealing performance of the compression chamber (61), the accuracy of prediction is improved.

[0143] -Modification 1 of embodiment 3- Modification 1 is an embodiment in which the predictive condition is changed from that of embodiment 3. In Modification 1, the predictive condition is that the increase rate Pr ((P-Pn) / Pn) of the internal pressure P of the compressor (50) with respect to a predetermined normal value Pn is equal to or greater than a reference value Pb (e.g., 0.1 (10%)) (Pr≧Pb).

[0144] The failure prediction unit (23) calculates the increase rate Pr of the internal pressure P of the compressor (50) relative to a predetermined normal value Pn, in the same manner as in the third embodiment. The failure prediction unit (23) calculates the increase rate Pr by subtracting the normal value Pn from the internal pressure P of the compressor (50) and dividing the result by the normal value Pn. Then, the failure prediction unit (23) compares the calculated increase rate Pr with a judgment reference value Pb, and determines that a predictive condition is established when the increase rate Pr is equal to or greater than the judgment reference value Pb (Pr≧Pb).

[0145] As described above, in the judgment operation, even if the object to be compared with the judgment reference value Pb is the increase rate Pr((P-Pn) / Pn) of the internal pressure P of the compressor (50) relative to a predetermined normal value Pn, the same effect as in the third embodiment can be achieved.

[0146] Fourth Embodiment The air conditioner (10) of the third embodiment is the same as the air conditioner (10) of the first embodiment, except that a pressure sensor (112) that detects the internal pressure of the compression chamber (61) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation by the failure prediction unit (23) is changed. The other configurations and operations are the same as those of the first embodiment. Here, the differences from the first embodiment will be described.

[0147] <Pressure Sensor> As shown in Fig. 4, the pressure sensor (112) is embedded in the compression section (60) so as to be able to detect the internal pressure of the compression chamber (61) of the compressor (50). A plurality of pressure sensors (112) are provided so as to be able to detect the internal pressure of the compression chamber (61) from the start of suction to the end of discharge. The pressure sensor (112) detects the internal pressure of the compression chamber (61), converts the detected internal pressure into an electric signal, and outputs the electric signal to the main controller (21).

[0148] <Judgment operation> The determination operation of the failure prediction unit (23) will be described. In the present embodiment, the failure prediction unit (23) also repeatedly performs a determination operation for determining whether a predictive condition is satisfied at predetermined time intervals (e.g., every 30 seconds). In the present embodiment, the predictive condition is a condition in which an increase Δκ(κ-κn) in the polytropic index κ during the compression process of the compressor (50) from a predetermined normal value κn is equal to or greater than a judgment reference value κb (Δκ≧κb). The polytropic index κ is expressed by the relational expression PV between the internal pressure P and the volume V of the compression chamber (61) during the compression process, κ = const., which indicates how the internal pressure changes with respect to the change in volume.

[0149] First, the failure prediction unit (23) calculates a polytropic index κ in the compression process of the compressor (50). The failure prediction unit (23) calculates the polytropic index κ from the internal pressure P (the value detected by the pressure sensor (112)) in the compression process of the compression chamber (61) and the volume V of the compression chamber (61) at that time.

[0150] Next, the failure prediction unit (23) calculates an increase Δκ of the polytropic index κ in the compression process of the compressor (50) relative to a predetermined normal value κn. The normal value κn is a polytropic index in the compression process of the compressor (50) in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value κn. The failure prediction unit (23) calculates the increase Δκ by subtracting the normal value κn from the polytropic index in the compression process of the compressor (50). The normal value κn may be a value determined in advance for each type of compressor (50). Alternatively, a trial run may be performed after the compressor system (40) is installed to calculate the polytropic index in the compression process of the compressor (50) in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated, and the calculated value may be the normal value κn. The normal value κn is determined for each operating condition of the compressor (50), which is constituted by the rotation speed, high pressure, and low pressure.

[0151] Next, the failure prediction unit (23) compares the calculated increase amount Δκ with a judgment reference value κb. The failure prediction unit (23) stores a reference value as the judgment reference value κb. The failure prediction unit (23) determines that the predictive condition is established when the increase amount Δκ is equal to or greater than the judgment reference value κb (Δκ≧κb). In other words, the failure prediction unit (23) of the present embodiment determines that the predictive condition is established when the increase amount Δκ becomes equal to or greater than the judgment reference value κb for the first time.

[0152] As described above, in the fourth embodiment, the failure prediction unit (23) calculates the polytropic index κ during the compression process of the compressor (50), and determines whether or not a predictive condition is satisfied (whether or not there are predictive signs of failure in the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the polytropic index κ during the compression process of the compressor (50). Note that in the fourth embodiment, the polytropic index κ (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of lubricating oil sealing the compression chamber (61), during the compression process of the compressor (50) is used as the predictive condition for the following reasons.

[0153] In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubrication state of each sliding part of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) changes from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) come into contact with each other and wear, and eventually the drive shaft (80) and the first to third bearings (79, 69, 93) break down (become inoperable) due to seizure or the like. Meanwhile, in the compression section (60), the amount of lubricating oil sealing the compression chamber (61) decreases before the lubrication state of each sliding part changes from fluid lubrication to mixed lubrication or boundary lubrication. When the amount of lubricating oil sealing the compression chamber (61) decreases, the sealing performance of the compression chamber (61) decreases, and a refrigerant leak occurs in which the refrigerant leaks from the compression chamber (61) with a higher internal pressure to the compression chamber (61) with a lower internal pressure. When a refrigerant leak occurs, as shown in Fig. 5, the internal pressure P in the compression chamber (61) into which the refrigerant leaks increases compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without poor lubrication), and the polytropic index κ in the compression process of the compressor (50) also increases compared to the normal state, and the internal pressure P in the compression chamber (61) from which the refrigerant leaks decreases compared to the normal state, and the polytropic index κ in the compression process of the compressor (50) also decreases compared to the normal state. Therefore, in the fourth embodiment, attention is focused on the polytropic index κ during the compression process of the compressor (50), which increases and decreases in conjunction with a sealing failure caused by a decrease in the amount of lubricating oil sealing the compression chamber (61). The polytropic index κ during the compression process of the compressor (50) is used to determine the presence or absence of signs of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). By using the polytropic index κ during the compression process of the compressor (50) to determine the presence or absence of signs of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after a decrease in the amount of oil in the oil reservoir (95), which may cause a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), the signs of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected and a failure can be predicted before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

[0154] In the fourth embodiment, when the refrigerant leakage occurs, the internal pressure P detected at the timing (rotation angle) when the pressure sensor (112) detects the internal pressure P increased compared to the normal state is used in the judgment operation. Therefore, in the judgment operation, the predictive condition is that the increase amount Δκ(κ-κn) of the polytropic index κ in the compression process of the compressor (50) from a predetermined normal value κn is equal to or greater than the judgment reference value κb (Δκ≧κb). Note that the internal pressure P detected at the timing (rotation angle) when the pressure sensor (112) detects the internal pressure P decreased compared to the normal state is used in the judgment operation, and the predictive condition in the judgment operation may be that the decrease amount Δκ(κn-κ) of the polytropic index κ in the compression process of the compressor (50) from a predetermined normal value κn is equal to or greater than the judgment reference value κb (Δκ≧κb).

[0155] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the fourth embodiment also provide the same effects as those of the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment. The polytropic index κ during the compression process of the compression chamber (61) changes in response to a change in the amount of seal oil in the compression chamber (61), but is not affected by friction between the drive shaft (55) and the first to third bearings (79, 69, 93). Therefore, the polytropic index κ during the compression process of the compression chamber (61) can easily detect a deterioration in the sealing performance of the compression chamber (61). Therefore, by detecting the polytropic index κ during the compression process of the compression chamber (61) as an index of a deterioration in the sealing performance of the compression chamber (61), the accuracy of prediction is improved.

[0156] -Modification 1 of embodiment 4- In the first modification, the predictive condition is changed from that in the fourth embodiment. In the first modification, the predictive condition is that the increase rate κr ((κ-κn) / κn) of the polytropic index κ in the compression process of the compressor (50) with respect to a predetermined normal value κn is equal to or greater than a reference value κb (for example, 0.1 (10%)) (κr≧κb).

[0157] The failure prediction unit (23) calculates an increase rate κr of the polytropic index κ in the compression process of the compressor (50) relative to a predetermined normal value κn, in the same manner as in the fourth embodiment. The failure prediction unit (23) calculates the increase rate κr by subtracting the normal value κn from the polytropic index κ in the compression process of the compressor (50) and dividing the result by the normal value κn. Then, the failure prediction unit (23) compares the calculated increase rate κr with a judgment reference value κb, and determines that a prediction condition is established when the increase rate κr is equal to or greater than the judgment reference value κb (κr≧κb).

[0158] As described above, in the judgment operation, even if the object to be compared with the judgment reference value κb is the increase rate κr ((κ-κn) / κn) of the polytropic index κ in the compression process of the compressor (50) relative to a predetermined normal value κn, the same effect as in the fourth embodiment can be achieved.

[0159] Fifth Embodiment The air conditioner (10) of the fifth embodiment is the same as the air conditioner (10) of the first embodiment, except that a power detection unit (113) that detects the input power to the motor (55) (output AC power of the motor drive device (45)) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation of the failure prediction unit (23) is changed. The other configurations and operations are the same as those of the first embodiment. Here, the differences from the first embodiment will be described.

[0160] <Power detection section> As shown in FIG. 6, the power detection unit (113) is provided on an electric wire (three windings (U-phase, V-phase, and W-phase windings) of the motor (55)) connecting the motor drive device (45) and the compressor (50). The power detection unit (113) detects the output AC power output from the motor drive device (45) to the motor (55) of the compressor (50) (i.e., the input power to the motor (55)). The power detection unit (113) outputs the detected input power to the main controller (21). It is not essential to provide the power detection unit (113), and the power supplied to the motor (55) may be detected in the motor drive device (45) or the main controller (21).

[0161] <Judgment operation> The determination operation of the failure prediction unit (23) will be described. In the present embodiment, the failure prediction unit (23) also repeatedly performs a determination operation for determining whether a predictive condition is satisfied at predetermined time intervals (e.g., every 30 seconds). In the present embodiment, the predictive condition is that an increase ΔJ (J-Jn) in the amount of electric power J input to the motor (55) from a predetermined normal value Jn is equal to or greater than a judgment reference value Jb (ΔJ≧Jb).

[0162] First, the failure prediction unit (23) calculates the amount of electric power J input to the motor (55) while the drive shaft (80) of the compressor (50) makes one rotation and the suction, compression, and discharge processes are performed in the compression chamber (61). The failure prediction unit (23) calculates the amount of electric power J input to the motor (55) by integrating the input power (the value detected by the power detection unit (113)) supplied from the motor drive device (45) to the motor (55) of the compressor (50) over the time required for the drive shaft (80) to make one rotation.

[0163] Next, the failure prediction unit (23) calculates an increase ΔJ of the amount of electric power J input to the motor (55) relative to a predetermined normal value Jn. The normal value Jn is the amount of electric power input to the motor (55) in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value Jn. The failure prediction unit (23) calculates the increase ΔJ by subtracting the normal value Jn from the amount of electric power J input to the motor (55). The normal value Jn may be a value determined in advance for each type of compressor (50). Alternatively, a test run may be performed after the compressor system (40) is installed, and the amount of electric power input to the motor (55) in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated may be calculated, and the calculated value may be the normal value Jn. The normal value Jn is determined for each operating condition of the compressor (50), which is the rotation speed, high pressure, and low pressure.

[0164] Next, the failure prediction unit (23) compares the calculated increase amount ΔJ with a judgment reference value Jb. The failure prediction unit (23) stores a reference value as the judgment reference value Jb. The failure prediction unit (23) determines that the predictive condition is established when the increase amount ΔJ is equal to or greater than the judgment reference value Jb (ΔJ≧Jb). In other words, the failure prediction unit (23) of the present embodiment determines that the predictive condition is established when the increase amount ΔJ becomes equal to or greater than the judgment reference value Jb for the first time.

[0165] As described above, in the fifth embodiment, the failure prediction section (23) calculates the amount of electric power J input to the motor (55) and determines whether or not a predictive condition is satisfied (whether or not there are predictive signs of failure in the drive shaft (80) and the first, second and third bearings (79, 69, 93)) based on the amount of electric power J input to the motor (55). Note that in the fifth embodiment, the amount of electric power J input to the motor (55) (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of lubricating oil sealing the compression chamber (61), is used as the predictive condition for the following reasons.

[0166] In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubrication state of each sliding part of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied through the oil supply passage (87) changes from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) come into contact with each other and wear, and eventually the drive shaft (80) and the first to third bearings (79, 69, 93) break down (become inoperable) due to seizure or the like. On the other hand, in the compression section (60), the amount of lubricating oil sealing the compression chamber (61) decreases before the lubrication state changes from fluid lubrication to mixed lubrication or boundary lubrication. When the amount of lubricating oil sealing the compression chamber (61) decreases, the sealing performance of the compression chamber (61) decreases, and refrigerant leakage occurs, that is, refrigerant leaks from the compression chamber (61) with a high internal pressure to the compression chamber (61) with a low internal pressure. When a refrigerant leak occurs, as shown in Fig. 5, the amount of work increases in the compression chamber (61) into which the refrigerant leaks and decreases in the compression chamber (61) from which the refrigerant leaks, but the compression chamber work W for one cycle increases as compared to the normal state (when the sliding parts of the compressor (50) are in a normal state with no poor lubrication). Here, the amount of electric power J input to the motor (55) is the compression chamber work W plus the frictional work. Therefore, when a refrigerant leak occurs, the amount of electric power J input to the motor (55) also increases as compared to the normal state. Therefore, in the fifth embodiment, attention is focused on the amount of electric power J input to the motor (55), which increases in conjunction with a sealing failure caused by a decrease in the amount of lubricating oil sealing the compression chamber (61), and the amount of electric power J input to the motor (55) is used to determine whether or not there are signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93). By using this amount of electric power J to determine whether or not there are signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) after a decrease in the amount of oil in the oil reservoir (95) occurs, which may cause a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), the signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected and a malfunction can be predicted before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

[0167] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the fifth embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment.

[0168] -Modification 1 of embodiment 5- In the first modification, the predictive condition is changed from that in the fifth embodiment. In the first modification, the predictive condition is that the increase rate Jr ((J-Jn) / Jn) of the amount of electric power J input to the motor (55) with respect to a predetermined normal value Jn is equal to or greater than a reference value Jb (for example, 0.1 (10%)) (Jr≧Jb).

[0169] The failure prediction unit (23) obtains the amount of electric power J input to the motor (55) in the same manner as in the fifth embodiment, and then calculates an increase rate Jr of the amount of electric power J input to the motor (55) with respect to a predetermined normal value Jn. The failure prediction unit (23) calculates the increase rate Jr by subtracting the normal value Jn from the amount of electric power J input to the motor (55) and dividing the result by the normal value Jn. The failure prediction unit (23) then compares the calculated increase rate Jr with a judgment reference value Jb, and determines that a prediction condition is established when the increase rate Jr is equal to or greater than the judgment reference value Jb (Jr≧Jb).

[0170] As described above, in the judgment operation, even if the object to be compared with the judgment reference value Jb is the increase rate Jr ((J-Jn) / Jn) of the amount of input electric power J to the motor (55) relative to a predetermined normal value Jn, the same effect as in embodiment 5 can be achieved.

[0171] Sixth Embodiment The air conditioner (10) of the sixth embodiment is the same as the air conditioner (10) of the first embodiment, except that an intake temperature sensor (114) and a volumetric flow rate sensor (115) are provided instead of the temperature sensor (111) for detecting the temperature of the discharge gas, and the determination operation of the failure prediction unit (23) is changed. The other configurations and operations are the same as those of the first embodiment. Here, the differences from the first embodiment will be described.

[0172] Sensors As shown in Fig. 7, the outdoor circuit (31) is provided with an intake temperature sensor (114) and a volumetric flow rate sensor (115). The intake temperature sensor (114) is connected to a pipe connecting the intake pipe (52) of the compressor (50) and the second port (P2) of the four-way switching valve (32) and detects the temperature of the refrigerant being drawn into the compressor (50). The volumetric flow rate sensor (115) is connected to a pipe connecting the intake pipe (52) of the compressor (50) and the second port (P2) of the four-way switching valve (32) and detects the volumetric flow rate of the refrigerant being drawn into the compressor (50). The intake temperature sensor (114) and the volumetric flow rate sensor (115) convert the detected volumetric flow rates of the refrigerant into electric signals and output the electric signals to the main controller (21).

[0173] <Judgment operation> The determination operation of the failure prediction unit (23) will be described. In the present embodiment, the failure prediction unit (23) also repeatedly performs a determination operation for determining whether a predictive condition is met at predetermined time intervals (e.g., every 30 seconds). In the present embodiment, the predictive condition is that a decrease ΔQ (Qn-Q) in the refrigeration capacity Q of the air conditioner (10) from a predetermined normal value Qn is equal to or greater than a determination reference value Qb (ΔQ≧Qb).

[0174] First, the failure prediction unit (23) calculates the refrigeration capacity Q of the air conditioner (10). Specifically, the failure prediction unit (23) calculates the refrigeration capacity Q of the air conditioner (10) based on the heat absorption difference Δq L and the refrigerant circulation amount G, and the difference in heat absorption Δq L and the product of the refrigerant circulation amount G (Δq L ×G) as the refrigeration capacity Q of the air conditioner (10). The failure prediction unit (23) calculates the heat absorption difference Δq from the pressure (detected by the suction pressure sensor (26)) and temperature (detected by the suction temperature sensor (114)) of the refrigerant suctioned into the compressor (50). L and then calculates the circulating amount G of the refrigerant from the volumetric flow rate (a value detected by the volumetric flow rate sensor (115)) of the refrigerant sucked into the compressor (50) and its density.

[0175] Next, the failure prediction unit (23) calculates a reduction amount ΔQ of the refrigeration capacity Q of the air conditioner (10) with respect to a predetermined normal value Qn. The normal value Qn is the refrigeration capacity of the air conditioner (10) in a normal state where the sliding parts of the compressor (50) are not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value Qn. The failure prediction unit (23) calculates the reduction amount ΔQ by subtracting the refrigeration capacity Q of the air conditioner (10) from the normal value Qn. The normal value Qn may be a value determined in advance for each type of compressor (50). Alternatively, after the compressor system (40) is installed, a test run may be performed to calculate the refrigeration capacity of the air conditioner (10) in a normal state where the sliding parts of the compressor (50) are not insufficiently lubricated, and the calculated value may be set as the normal value Qn. The normal value Qn is determined for each condition consisting of the rotation speed and the difference in heat absorption amount.

[0176] Next, the failure prediction unit (23) compares the calculated decrease amount ΔQ with a judgment reference value Qb. The failure prediction unit (23) stores a reference value as the judgment reference value Qb. The failure prediction unit (23) determines that the predictive condition is met when the decrease amount ΔQ is equal to or greater than the judgment reference value Qb (ΔQ≧Qb). In other words, the failure prediction unit (23) of the present embodiment determines that the predictive condition is met when the decrease amount ΔQ becomes equal to or greater than the judgment reference value Qb for the first time.

[0177] As described above, in the sixth embodiment, the failure prediction unit (23) calculates the refrigeration capacity Q of the air conditioner (10) and determines whether or not a predictive condition is met (whether or not there are predictive conditions for failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the refrigeration capacity Q of the air conditioner (10). Note that in the sixth embodiment, the refrigeration capacity Q of the air conditioner (10) (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of lubricating oil sealing the compression chamber (61), is used as the predictive condition for the following reasons.

[0178] In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubrication state of each sliding part of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) changes from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) come into contact with each other and wear, and eventually the drive shaft (80) and the first to third bearings (79, 69, 93) break down (become inoperable) due to seizure or the like. Meanwhile, in the compression section (60), the amount of lubricating oil sealing the compression chamber (61) decreases before the lubrication state of each sliding part changes from fluid lubrication to mixed lubrication or boundary lubrication. When the amount of lubricating oil sealing the compression chamber (61) decreases, the sealing ability of the compression chamber (61) decreases, causing a refrigerant leakage, that is, refrigerant leaking from the compression chamber (61) with a higher internal pressure to the compression chamber (61) with a lower internal pressure. When a refrigerant leakage occurs, high-pressure gas (refrigerant) leaking from the high-pressure side flows into the suction side, causing a decrease in the amount G of refrigerant circulating in the refrigerant circuit (30) compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without poor lubrication), and the refrigeration capacity Q of the air conditioner (10) also decreases. Therefore, in the sixth embodiment, attention is focused on the refrigeration capacity Q of the air conditioner (10), which decreases in conjunction with a sealing failure caused by a decrease in the amount of lubricating oil sealing the compression chamber (61), and the refrigeration capacity Q of the air conditioner (10) is used to determine whether or not there are signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93). By using this refrigeration capacity Q of the air conditioner (10) to determine whether or not there are signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) after a decrease in the amount of oil in the oil reservoir (95), which may cause a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), the signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected and a malfunction can be predicted before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

[0179] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the sixth embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment.

[0180] -Modification 1 of embodiment 6- Modification 1 is an embodiment in which the predictive condition is changed from that of embodiment 6. In Modification 1, the predictive condition is that the rate of decrease Qr ((Qn-Q) / Qn) of the refrigeration capacity Q of the air conditioner (10) with respect to a predetermined normal value Qn is equal to or greater than a reference value Qb (e.g., 0.1 (10%)) (Qr≧Qb).

[0181] The failure prediction unit (23) calculates the refrigeration capacity Q of the air conditioner (10) in the same manner as in the sixth embodiment, and then calculates a decrease rate Qr of the refrigeration capacity Q of the air conditioner (10) relative to a predetermined normal value Qn. The failure prediction unit (23) calculates the decrease rate Qr by subtracting the refrigeration capacity Q of the air conditioner (10) from the normal value Qn and dividing the result by the normal value Qn. The failure prediction unit (23) then compares the calculated decrease rate Qr with a judgment reference value Qb, and determines that a prediction condition is established if the decrease rate Qr is equal to or greater than the judgment reference value Qb (Qr≧Qb).

[0182] As described above, in the judgment operation, even if the object to be compared with the judgment reference value Qb is the rate of decline Qr ((Qn-Q) / Qn) of the refrigeration capacity Q of the air conditioner (10) relative to a predetermined normal value Qn, the same effect as in embodiment 6 can be achieved.

[0183] Seventh Embodiment The air conditioner (10) of the seventh embodiment is configured by providing a current detection unit (116) and a fundamental frequency detection unit (117) for detecting an input current (three-phase current of the motor drive device (45)) for driving the motor (55) instead of the temperature sensor (111) for detecting the temperature of the discharge gas in the air conditioner (10) of the first embodiment, and by changing the determination operation of the failure prediction unit (23). The other configurations and operations are the same as those of the first embodiment. Here, the differences from the first embodiment will be described.

[0184] <Current detection section, fundamental frequency detection section> As shown in FIG. 8 , the current detection unit (116) is provided in an electric wire (three windings (U-phase, V-phase, and W-phase windings) of the motor (55)) connecting the motor drive device (45) and the compressor (50), and detects three-phase currents (U-phase current (iu), V-phase current (iv), and W-phase current (iw)). The current detection unit (116) outputs the detected three-phase currents to the main controller (21). For example, the current detection unit (116) may detect all of the three-phase currents (iu, iv, iw), or may detect two of the three-phase currents (iu, iv, iw) and derive the remaining phase current based on the detected two-phase currents. In addition, the current detection unit (116) does not necessarily have to be provided, and the three-phase currents (iu, iv, iw) may be derived from the DC current detected by a shunt resistor (not shown) provided in a DC unit (not shown) of the motor drive device (45) and the switching pattern.

[0185] As shown in Fig. 8, the fundamental frequency detection unit (117) is provided in the motor (55) and detects the fundamental frequency (ω) of the motor (55). The fundamental frequency (ω) of the motor (55) is the frequency of the electrical angle of the motor (55) (electrical angle frequency). The fundamental frequency detection unit (117) outputs the detected fundamental frequency (ω) of the motor (55) to the main controller (21). The fundamental frequency detection unit (117) is not necessarily provided, and the fundamental frequency (ω) of the motor (55) may be calculated by another method or estimated in a sensorless manner.

[0186] <Judgment operation> The determination operation of the failure prediction unit (23) will be described. In the present embodiment as well, the failure prediction unit (23) repeatedly performs a determination operation for determining whether a predictive condition is satisfied at predetermined time intervals (e.g., every 30 seconds). In the present embodiment, the predictive condition is a condition that a decrease amount ΔI (In-I) of an index I indicating a waveform of a motor signal correlated with at least one of the voltage, current, and power of the motor (55) from a predetermined normal value In is equal to or greater than a determination reference value Ib (ΔI≧Ib). Note that in the seventh embodiment, an example will be described in which a first frequency component I of a motor signal correlated with at least one of the voltage, current, and power of the motor (55) is used as the index I indicating a waveform of a motor signal correlated with at least one of the voltage, current, and power of the motor (55).

[0187] First, the failure prediction unit (23) obtains a first frequency component I of the motor signal. The first frequency component I of the motor signal is the rotational frequency of the motor (55) when the motor signal is a DC signal, and is a frequency obtained by subtracting or adding the rotational frequency of the motor (55) to or from the fundamental frequency of the motor signal when the motor signal is an AC signal. The first frequency component I of the motor signal will be described in detail later. The rotational frequency of the motor (55) is the frequency of the mechanical angle of the motor (55) (mechanical angular frequency).

[0188] Next, the failure prediction unit (23) calculates a decrease amount ΔI of the first frequency component I of the motor signal with respect to a predetermined normal value In. The normal value In is the first frequency component of the motor signal in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value In. The failure prediction unit (23) calculates the decrease amount ΔI by subtracting the first frequency component I of the motor signal from the normal value In. The normal value In may be a value determined in advance for each type of compressor (50). Alternatively, after installation of the compressor system (40), a trial run may be performed to determine the first frequency component of the motor signal in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated, and the determined value may be set as the normal value In. The normal value In is determined for each operating condition of the compressor (50), which is the rotation speed, high pressure, and low pressure.

[0189] Next, the failure prediction unit (23) compares the calculated amount of decrease ΔI with the judgment reference value Ib. The failure prediction unit (23) stores a reference value as the judgment reference value Ib. The failure prediction unit (23) determines that the predictive condition is satisfied when the amount of decrease ΔI is equal to or greater than the judgment reference value Ib (ΔI≧Ib). That is, the failure prediction unit (23) of the present embodiment determines that the predictive condition is satisfied when the amount of decrease ΔI becomes equal to or greater than the judgment reference value Ib for the first time. For example, when the first frequency component I of the motor signal changes as shown in FIG. 9, the failure prediction unit (23) determines that the predictive condition is satisfied at a judgment time point after t1 when the amount of decrease ΔI of the first frequency component I of the motor signal with respect to the normal value In becomes the judgment reference value Ib.

[0190] As described above, in the seventh embodiment, the failure prediction unit (23) obtains the first frequency component I of the motor signal, and determines whether or not the predictive condition is satisfied (whether or not there are predictive signs of failure in the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the first frequency component I of the motor signal.

[0191] The inventors of the present application have found that the first frequency component I of the motor signal is dominant in the work of the compressor and is correlated with the amplitude of the internal pressure during the compression stroke (the difference between the minimum and maximum pressures), and that when the sealing performance of the compression chamber (61) deteriorates and fluid leakage occurs, the amplitude of the internal pressure of the compression chamber (61) during the compression stroke decreases and the first frequency component I of the motor signal changes. Therefore, in the seventh embodiment, the first frequency component I of the motor signal (an index showing the operating state of the compression section (60)) is used as the predictive condition for the following reasons.

[0192] In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubrication state of each sliding part of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) changes from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) come into contact with each other and wear, and eventually the drive shaft (80) and the first to third bearings (79, 69, 93) break down (become inoperable) due to seizure or the like. Meanwhile, in the compression section (60), the amount of lubricating oil sealing the compression chamber (61) decreases before the lubrication state of each sliding part changes from fluid lubrication to mixed lubrication or boundary lubrication. When the amount of lubricating oil sealing the compression chamber (61) decreases, the sealing performance of the compression chamber (61) decreases, causing refrigerant leakage, that is, leakage of refrigerant from the compression chamber (61) with a higher internal pressure to the compression chamber (61) with a lower internal pressure.

[0193] When refrigerant leakage occurs, the internal pressure waveform indicating the fluctuation of the internal pressure of the compression chamber (61) changes, and the gas load (the load that the pressure of the gas refrigerant exerts on the orbiting-side wrap (76)) changes. This changes the waveform of a signal (compression torque signal) indicating the compression torque of the compressor (50), which is expressed as the sum of the products of the “tangential component of the gas load” of each compression chamber (61) and the “distance between the center of rotation and the center of gravity of the compression chamber (61)”. The waveform of the compression torque signal and the waveform of the motor output torque signal are linked, and when refrigerant leakage occurs, a change also appears in the waveform of the motor signal, which is linked to the waveform of the motor output torque signal. Specifically, when refrigerant leakage occurs, the first frequency component I of the motor signal (an example of an index I indicating the waveform of the motor signal) decreases compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without poor lubrication).

[0194] Therefore, in the seventh embodiment, attention is focused on the first frequency component I of the motor signal, which decreases in conjunction with a sealing failure caused by a decrease in the amount of lubricating oil sealing the compression chamber (61), and the first frequency component I of the motor signal is used to determine whether or not there are signs of a failure in the drive shaft (80) and the first to third bearings (79, 69, 93).By doing so, after a decrease in the amount of oil in the oil reservoir (95) occurs, which may cause a failure in the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), the signs of a failure in the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected and a failure can be predicted before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

[0195] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the seventh embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment. Furthermore, the first frequency component I of the motor signal changes in response to a change in the amount of seal oil in the compression chamber (61), but is not affected by friction between the drive shaft (55) and the first to third bearings (79, 69, 93). Therefore, the first frequency component I of the motor signal is easy to detect a deterioration in the sealing performance of the compression chamber (61), and the accuracy of prediction is improved by detecting the first frequency component I of the motor signal as an index of the deterioration in the sealing performance of the compression chamber (61).

[0196] <First frequency component of motor signal> Next, a specific example of the first frequency component I of the motor signal will be described. The motor signal is a signal that is correlated with at least one of the voltage, current, and power of the motor (55), and the frequency of the first frequency component I differs depending on whether the motor signal is a DC signal or an AC signal. When the motor signal is a DC signal, the frequency of the first frequency component I is the rotation frequency (fm) of the motor (55), and when the motor signal is an AC signal, the frequency of the first frequency component I is a frequency (f0-fm) obtained by subtracting the rotation frequency (fm) of the motor (55) from the fundamental frequency (f0) of the motor signal, or a frequency (f0+fm) obtained by adding the rotation frequency (fm) of the motor (55) to the fundamental frequency (f0) of the motor signal.

[0197] [Example when the motor signal is a DC signal] Examples of the motor signal being a DC signal include a "signal correlating to the phase currents (iu, iv, iw) of the motor (55)," a "signal correlating to the phase voltages (Vu, Vv, Vw) of the motor (55)," and a "signal correlating to the power of the motor (55)."

[0198] Another example of the motor signal being a DC signal is "current (iγ, iδ) obtained by coordinate transformation of the phase current (iu, iv, iw) of the motor (55) with the phase (ωi·t) of the phase current (iu, iv, iw) of the motor (55)" and "voltage (V These include "currents (iζ, iη) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (55) with the phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (55)" and "voltages (Vζ, Vη) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (55) with the phase (ωi·t) of the phase currents (iu, iv, iw) of the motor (55)."

[0199] Further examples of motor signals that are DC signals include "dq-axis magnetic flux (λd, λq) coordinate-transformed to match the armature flux linkage caused by a permanent magnet" and "the magnitude of the armature flux linkage vector λ0, which is the composite of the armature flux linkage of the permanent magnet and the armature reaction."

[0200] In the following description, the term "phase currents (iu, iv, iw) of the motor (55)" refers to the phase currents (iu, iv, iw) of the motor (55) detected by the current detection unit (116). The term "phase voltages (Vu, Vv, Vw) of the motor (55)" refers to the phase voltages (Vu, Vv, Vw) of the motor (55) indicated in a voltage command value used inside the main controller (21) or the phase voltages (Vu, Vv, Vw) of the motor (55) detected by a voltage detection unit (not shown) provided in the motor drive device (45). The term "fundamental frequency (ω) of the motor (55)" refers to the fundamental frequency (ω) of the motor (55) detected by the fundamental frequency detection unit (117).

[0201] <Examples of signals correlated to motor phase currents> Specific examples of signals correlated with the phase currents (iu, iv, iw) of the motor (55) include: (1) the current vector amplitude (Ia), (2) the square value of the current vector amplitude (Ia 2 ), phase current amplitude (I), and (3) phase current effective value (Irms).

[0202] In addition, the current vector amplitude (Ia) and the square value of the current vector amplitude (Ia 2 ) is an example of a value proportional to the sum of the squares of the three phase currents (iu, iv, iw) of the motor (55). The value proportional to the sum of the squares of the three phase currents (iu, iv, iw) of the motor (55) is an example of a value proportional to an integer power of the magnitude of the phase currents (iu, iv, iw) of the motor (55).

[0203] (1) Current vector amplitude The current vector amplitude (Ia) is derived based on the phase currents (iu, iv, iw) of the motor (55). The current vector amplitude (Ia) may also be derived based on an α-phase current (iα) and a β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (55) into a fixed coordinate system. The current vector amplitude (Ia) may also be derived based on an M-axis current (iM) and a T-axis current (iT) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (55) by an angle based on the direction of the primary magnetic flux. The current vector amplitude (Ia) may also be derived based on a d-axis current (id) and a q-axis current (iq) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (55) by an angle based on the direction of the magnetic pole position. Specifically, the current vector amplitude (Ia) can be expressed as follows:

[0204]

number

[0205] (2) Square value of the current vector amplitude The squared value of the current vector magnitude (Ia 2 ) is derived based on the phase currents (iu, iv, iw) of the motor (55). 2 ) may be derived based on an α-phase current (iα) and a β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (55) into a fixed coordinate system. 2 ) may be derived based on the M-axis current (iM) and the T-axis current (iT) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (55) by an angle based on the direction of the primary magnetic flux. 2 ) may be derived based on the d-axis current (id) and the q-axis current (iq) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (55) by an angle based on the orientation of the magnetic pole position. 2 ) can be expressed as the following formula:

[0206]

number

[0207] (3) Phase current amplitude The phase current amplitude (I) is derived based on one of the phase currents (iu, iv, iw) of the motor (55), for example, the U-phase current (iu), and the phase current phase (ωi). The phase current phase (ωi) is derived based on the phase currents (iu, iv, iw) of the motor (55), for example. Specifically, the phase current amplitude (I) can be expressed by the following equation.

[0208]

number

[0209] (4) Phase current effective value The phase current effective value (Irms) is derived based on the phase current amplitude (I). Specifically, the phase current effective value (Irms) can be expressed as follows:

[0210]

number

[0211] (5)Other In the above description, an example has been given in which the current vector amplitude (Ia) is derived based on the three-phase currents (iu, iv, iw) of the motor (55). However, the current vector amplitude (Ia) may be derived based on two of the three-phase currents (iu, iv, iw) of the motor (55). The current vector amplitude (Ia) may also be derived based on a DC current of an inverter detected by a DC current detection unit (e.g., a shunt resistor, not shown) provided in the motor drive device (45). The square value of the current vector amplitude (Ia 2 ) is also similar.

[0212] <Examples of signals correlated to motor phase voltages> Specific examples of signals correlated with the phase voltages (Vu, Vv, Vw) of the motor (55) include: (1) voltage vector amplitude (Va), (2) the square of the voltage vector amplitude (Va 2 ), (3) phase voltage amplitude (V), and (4) phase voltage effective value (Vrms).

[0213] In addition, the voltage vector amplitude (Va) and the square value of the voltage vector amplitude (Va 2 ) is an example of a value proportional to the sum of the squares of the three phase voltages (Vu, Vv, Vw) of the motor (55). The value proportional to the sum of the squares of the three phase voltages (Vu, Vv, Vw) of the motor (55) is an example of a value proportional to an integer power of the magnitude of the phase voltages (Vu, Vv, Vw) of the motor (55).

[0214] (1) Voltage Vector Amplitude The voltage vector amplitude (Va) is derived based on the phase voltages (Vu, Vv, Vw) of the motor (55). The voltage vector amplitude (Va) may be derived based on an α-phase voltage (Vα) and a β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (55) into a fixed coordinate system. The voltage vector amplitude (Va) may be derived based on an M-axis voltage (VM) and a T-axis voltage (VT) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (55) by an angle based on the direction of the primary magnetic flux. The voltage vector amplitude (Va) may be derived based on a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (55) by an angle based on the direction of the magnetic pole position. Specifically, the voltage vector amplitude (Va) can be expressed by the following equation.

[0215]

number

[0216] (2) Squared value of voltage vector amplitude Voltage vector magnitude squared value (Va 2 ) is derived based on the phase voltages (Vu, Vv, Vw) of the motor (55).2 ) may be derived based on an α-phase voltage (Vα) and a β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (55) into a fixed coordinate system. 2 ) may be derived based on the M-axis voltage (VM) and the T-axis voltage (VT) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (55) by an angle based on the direction of the primary magnetic flux. 2 ) may be derived based on a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate transformation of the phase voltages (Vu, Vv, Vw) of the motor (55) by an angle based on the orientation of the magnetic pole position. 2 ) can be expressed as the following formula:

[0217]

number

[0218] (3) Phase voltage amplitude The phase voltage amplitude (V) is derived based on one of the phase voltages (Vu, Vv, Vw) of the motor (55), for example, the U-phase voltage (Vu), and the phase voltage phase (ωv). The phase voltage phase (ωv) is derived based on the phase voltages (Vu, Vv, Vw) of the motor (55), for example. Specifically, the phase voltage amplitude (V) can be expressed by the following equation.

[0219]

number

[0220] (4) Phase voltage effective value The phase voltage effective value (Vrms) is derived based on the phase voltage amplitude (V). Specifically, the phase voltage effective value (Vrms) can be expressed as follows:

[0221]

number

[0222] (5)Other In the above description, an example has been given in which the voltage vector amplitude (Va) is derived based on the three-phase voltages (Vu, Vv, Vw) of the motor (55), but the voltage vector amplitude (Va) may be derived based on two of the three-phase voltages (Vu, Vv, Vw) of the motor (55). 2 ) is also similar.

[0223] <Examples of signals correlated with motor power> Examples of signals correlated to the power of the motor (55) include (1) instantaneous power (p), (2) instantaneous imaginary power (q), (3) apparent power (S), (4) active power (P), and (5) reactive power (Q).

[0224] (1) Instantaneous power The instantaneous power (p) is derived based on the phase currents (iu, iv, iw) of the motor (55) and the phase voltages (Vu, Vv, Vw) of the motor (55). Alternatively, the instantaneous power (p) may be derived based on an α-phase current (iα) and a β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (55) into a fixed coordinate system, and an α-phase voltage (Vα) and a β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (55) into the fixed coordinate system. The instantaneous power (p) may be derived based on an M-axis current (iM) and a T-axis current (iT) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (55) by an angle based on the direction of the primary magnetic flux, and an M-axis voltage (VM) and a T-axis voltage (VT) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (55) by an angle based on the direction of the primary magnetic flux. The instantaneous power (p) may be derived based on a d-axis current (id) and a q-axis current (iq) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (55) by an angle based on the direction of the magnetic pole position, and a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (55) by an angle based on the direction of the magnetic pole position. Specifically, the instantaneous power (p) can be expressed as follows:

[0225]

number

[0226] (2) Instantaneous reactive power The instantaneous imaginary power (q) is derived based on an α-phase current (iα) and a β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (55) into a fixed coordinate system, and an α-phase voltage (Vα) and a β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (55) into a fixed coordinate system. The instantaneous imaginary power (q) may also be derived based on an M-axis current (iM) and a T-axis current (iT) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (55) by an angle based on the direction of the primary magnetic flux, and an M-axis voltage (VM) and a T-axis voltage (VT) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (55) by an angle based on the direction of the primary magnetic flux. In addition, the instantaneous imaginary power (q) may be derived based on a d-axis current (id) and a q-axis current (iq) obtained by coordinate transforming the phase currents (iu, iv, iw) of the motor (55) by an angle based on the orientation of the magnetic pole position, and a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate transforming the phase voltages (Vu, Vv, Vw) of the motor (55) by an angle based on the orientation of the magnetic pole position. Specifically, the instantaneous imaginary power (q) can be expressed by the following equation.

[0227]

number

[0228] (3) Apparent power The apparent power (S) is derived based on the phase voltage effective value (Vrms) and the phase current effective value (Irms). Specifically, the apparent power (S) can be expressed by the following equation.

[0229]

number

[0230] (4) Active power The active power (P) is derived based on the phase voltage effective value (Vrms), the phase current effective value (Irms), and the phase difference (φ1) between the phase voltage and the phase current. The phase difference (φ1) between the phase voltage and the phase current is the phase difference between one phase current (e.g., U-phase voltage (Vu)) and one phase voltage (e.g., U-phase current (iu)), and is derived based on the phase (ωi) of the phase current and the phase (ωv) of the phase voltage. Specifically, the active power (P) can be expressed as follows:

[0231]

number

[0232] (5) Reactive power The reactive power (Q) is derived based on the phase voltage effective value (Vrms), the phase current effective value (Irms), and the phase difference (φ1) between the phase voltage and the phase current. The phase difference (φ1) between the phase voltage and the phase current is, for example, the phase difference between the U-phase voltage (Vu) and the U-phase current (iu), and is derived based on the phase (ωi) of the phase current and the phase (ωv) of the phase voltage. Specifically, the reactive power (Q) can be expressed as follows:

[0233]

number

[0234] <Current obtained by coordinate transformation of phase current with phase current phase> The currents (iγ, iδ) obtained by coordinate transformation of the phase currents (iu, iv, iw) of the motor (55) using the phase (ωi t) of the phase currents (iu, iv, iw) of the motor (55) can be expressed by the following equation.

[0235]

number

[0236] <Voltage obtained by coordinate conversion of phase voltage with the phase voltage phase> The voltages (Vγ, Vδ) obtained by performing coordinate transformation on the phase voltages (Vu, Vv, Vw) of the motor (55) with the phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (55) can be expressed as follows.

[0237]

Equation

[0238] <Current obtained by performing coordinate transformation on the phase current with the phase of the phase voltage> The currents (iζ, iη) obtained by performing coordinate transformation on the phase currents (iu, iv, iw) of the motor (55) with the phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (55) can be expressed as follows.

[0239]

Equation

[0240] <Voltage obtained by performing coordinate transformation on the phase voltage with the phase of the phase current> The voltages (Vζ, Vη) obtained by performing coordinate transformation on the phase voltages (Vu, Vv, Vw) of the motor (55) with the phase (ωi·t) of the phase currents (iu, iv, iw) of the motor (55) can be expressed as follows.

[0241]

Equation

[0242] <Magnitude of dq-axis flux and armature cross-flux vector> The magnitudes λ0 of the dq-axis fluxes (λd, λq) obtained by performing coordinate transformation in accordance with the armature cross-flux due to the permanent magnet and the armature cross-flux vector obtained by synthesizing the armature cross-flux of the permanent magnet and the armature reaction can be expressed as follows. "Ld" in the following equation is the d-axis inductance, and "Lq" is the q-axis inductance.

[0243]

Equation

[0244] <Other examples when the motor signal is a DC signal> The motor signal may be a DC signal obtained by performing three-phase to two-phase conversion on the phase current, phase voltage, line current, or line voltage of the motor (55) and further performing rotational coordinate conversion. For example, the motor signal (DC signal) may be a d-axis current and a q-axis current obtained by performing rotational coordinate conversion at an angle based on the orientation of the magnetic poles of the rotor of the motor (55) on an α-axis current and a β-axis current obtained by performing three-phase to two-phase conversion on the phase current of the motor (55). The motor signal (DC signal) may be an M-axis current and a T-axis current obtained by performing rotational coordinate conversion on the α-axis current and the β-axis current on an angle based on the orientation of the primary magnetic flux of the rotor of the motor (55).

[0245] In addition, the motor signal (DC signal) may be power input to the converter (21) of the motor drive device (45), power output from the converter (21), power output from the DC section (22), a current flowing between the converter (21) and the DC section (22), a current flowing between the DC section (22) and the inverter (23), etc.

[0246] [Specific example when the motor signal is an AC signal] Examples of the motor signals when they are AC signals include “phase currents (iu, iv, iw) of the motor (55),” “phase voltages (Vu, Vv, Vw) of the motor (55),” and “flux linkage of each phase (Ψfu, Ψfv, Ψfw).”

[0247] The interlinkage magnetic flux of each phase (Ψfu, Ψfv, Ψfw) can be expressed as follows:

[0248]

number

[0249] Another example of the motor signal when it is an AC signal is a current and voltage flux linkage of fixed coordinates obtained by three-phase to two-phase conversion of the AC signal.

[0250] The motor signal (AC signal) may be a phase current, a phase voltage, a line current, a line voltage, etc. of the motor (55). The motor signal (AC signal) may be a two-phase AC current (e.g., an α-axis current and a β-axis current) or a two-phase AC voltage obtained by three-phase to two-phase conversion of the phase current, the phase voltage, the line current, or the line voltage. The AC current may be a current flowing between a commercial power supply system (specifically, the AC power supply (60)) and the converter (21) of the motor drive device (45).

[0251] In the seventh embodiment, the first frequency component I of the motor signal has been described as an example of the index I indicating the waveform of the motor signal, but the index I indicating the waveform of the motor signal is not limited to this. For example, the index I indicating the waveform of the motor signal may be obtained by integrating, for one rotation of the motor (55), the absolute value of the difference ((Iinst-Iavg) / Iavg) obtained by subtracting the average value Iavg of the motor signal (DC signal) for one rotation of the motor (55) from the instantaneous value Iinst of the motor signal (DC signal), and dividing the difference by the average value Iavg of the motor signal (DC signal) for one rotation of the motor (55). Like the first frequency component I of the motor signal, this value also decreases when the amount of lubricating oil sealing the compression chamber (61) decreases, compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without insufficient lubrication).

[0252] -Modification 1 of the seventh embodiment- Modification 1 is an example in which the predictive condition is changed from that of embodiment 7. In modification 1, the predictive condition is that the rate of decrease Ir ((In-I) / In) of the first frequency component I of the motor signal with respect to a predetermined normal value In is equal to or greater than a reference value Ib (e.g., 0.1 (10%)) (Ir≧Ib).

[0253] The failure prediction unit (23) obtains the first frequency component I of the motor signal in the same manner as in the seventh embodiment, and then calculates a decrease rate Ir of the first frequency component I of the motor signal with respect to a predetermined normal value In. The failure prediction unit (23) calculates the decrease rate Ir by subtracting the first frequency component I of the motor signal from the normal value In and dividing the result by the normal value In. Then, the failure prediction unit (23) compares the calculated decrease rate Ir with a judgment reference value Ib, and determines that a prediction condition is established when the decrease rate Ir is equal to or greater than the judgment reference value Ib (Ir≧Ib).

[0254] As described above, in the judgment operation, even if the object to be compared with the judgment reference value Ib is the decrease rate Ir ((In-I) / In) of the first frequency component I of the motor signal relative to a predetermined normal value In, the same effect as in embodiment 7 can be achieved.

[0255] Eighth embodiment The air conditioner (10) of the eighth embodiment is the same as the air conditioner (10) of the first embodiment, except that a pressure sensor (112) that detects the internal pressure of the compression chamber (61) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation by the failure prediction unit (23) is changed. The rest of the configuration and operation are the same as those of the first embodiment. Here, the differences from the first embodiment will be described.

[0256] <Pressure Sensor> As shown in Fig. 4, the pressure sensor (112) is embedded in the compression section (60) so as to be able to detect the internal pressure of the compression chamber (61) of the compressor (50). A plurality of pressure sensors (112) are provided so as to be able to detect the internal pressure of the compression chamber (61) from the start of suction to the end of discharge. The pressure sensor (112) detects the internal pressure of the compression chamber (61), converts the detected internal pressure into an electric signal, and outputs the electric signal to the main controller (21).

[0257] <Judgment operation> The determination operation of the failure prediction unit (23) will be described. In the present embodiment, the failure prediction unit (23) also repeatedly performs a determination operation for determining whether a predictive condition is satisfied at predetermined time intervals (e.g., every 30 seconds). In the present embodiment, the predictive condition is a condition in which a decrease amount ΔTc (Tcn-Tc) of an index T indicating a waveform of a signal (compression torque signal) indicating the compression torque of the compressor (50) from a predetermined normal value Tcn is equal to or greater than a determination reference value Tcb (ΔTc≧Tcb). In the eighth embodiment, an example will be described in which the rotation frequency component Tc of the motor (55) is used as the index T indicating the waveform of the compression torque signal.

[0258] Here, the "compression torque of the compressor (50)" refers to the load torque required to rotate the compressor (50) minus losses due to friction and the like, i.e., the gas compression torque required to compress the gas (refrigerant).

[0259] First, the failure prediction unit (23) calculates the compression torque while the compressor (50) is performing each of the suction, compression, and discharge processes, and obtains a rotational frequency component Tc of a signal indicating the compression torque (compression torque signal) of the motor (55). The failure prediction unit (23) calculates the compression torque by integrating a tangential component Fpt perpendicular to a radial component of a force acting in the eccentric direction of the drive shaft (80) by the compressed gas (refrigerant), with the radius of gyration r of the drive shaft (80).

[0260] A tangential component Fpt perpendicular to the radial component of the force acting in the eccentric direction of the drive shaft (80) by the compressed gas (refrigerant) can be expressed by the following equation: In the following equation, "Pi" is the internal pressure of the ith compression chamber (61) from the center, "h" is the height of the wrap (72, 76), "Ps" is the suction pressure, "Pd" is the discharge pressure, "λpi" is the expansion angle of the ith compression chamber (61), "a" is the base circle radius of the involute, and "t" is the thickness of the wrap (72, 76).

[0261]

number

[0262] Next, the failure prediction unit (23) calculates a decrease amount ΔTc of the rotation frequency component Tc of the motor (55) of the compression torque signal with respect to a predetermined normal value Tcn. The normal value Tcn is the rotation frequency component of the motor (55) of the compression torque signal in a normal state where the sliding parts of the compressor (50) are not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value Tcn. The failure prediction unit (23) calculates the decrease amount ΔTc by subtracting the normal value Tcn from the rotation frequency component Tc of the motor (55) of the compression torque signal. The normal value Tcn may be a value determined in advance for each type of compressor (50). Alternatively, a trial run may be performed after the installation of the compressor system (40) to determine the rotation frequency component of the motor (55) of the compression torque signal in a normal state where the sliding parts of the compressor (50) are not insufficiently lubricated, and the determined value may be the normal value Tcn. The normal value Tcn is determined for each operating condition of the compressor (50), which is constituted by the rotation speed, high pressure, and low pressure.

[0263] Next, the failure prediction unit (23) compares the calculated decrease ΔTc with a judgment reference value Tcb. The failure prediction unit (23) stores a reference value as the judgment reference value Tcb. The failure prediction unit (23) determines that the predictive condition is met when the decrease ΔTc is equal to or greater than the judgment reference value Tcb (ΔTc≧Tcb). In other words, the failure prediction unit (23) of the present embodiment determines that the predictive condition is met when the decrease ΔTc becomes equal to or greater than the judgment reference value Tcb for the first time.

[0264] As described above, in the eighth embodiment, the failure prediction unit (23) obtains the rotation frequency component Tc of the motor (55) of the compression torque signal, and determines whether or not the predictive condition is satisfied (whether or not there is a predictive condition of failure in the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the rotation frequency component Tc of the motor (55) of the compression torque signal. Note that in the eighth embodiment, the rotation frequency component Tc of the motor (55) of the compression torque signal (an index indicating the operating state of the compression unit (60)), which changes in conjunction with the amount of lubricating oil sealing the compression chamber (61), is used as the predictive condition for the following reasons.

[0265] In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubrication state of each sliding part of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) changes from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) come into contact with each other and wear, and eventually the drive shaft (80) and the first to third bearings (79, 69, 93) break down (become inoperable) due to seizure or the like. Meanwhile, in the compression section (60), the amount of lubricating oil sealing the compression chamber (61) decreases before the lubrication state of each sliding part changes from fluid lubrication to mixed lubrication or boundary lubrication. When the amount of lubricating oil sealing the compression chamber (61) decreases, the sealing performance of the compression chamber (61) decreases, causing refrigerant leakage, that is, leakage of refrigerant from the compression chamber (61) with a higher internal pressure to the compression chamber (61) with a lower internal pressure.

[0266] When refrigerant leakage occurs, an internal pressure waveform indicating fluctuations in the internal pressure of the compression chamber (61) changes, and the gas load (the load that the pressure of the gas refrigerant exerts on the orbiting-side wrap (76)) changes. This changes the waveform of a signal indicating the compression torque of the compressor (50) (compression torque signal), which is expressed as the sum of the products of the "tangential component of the gas load" of each compression chamber (61) and the "distance between the center of rotation and the center of gravity of the compression chamber (61)". Specifically, when refrigerant leakage occurs, a rotation frequency component Tc of the motor (55) of the compression torque signal (an example of an index T indicating the waveform of the compression torque signal) decreases compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without poor lubrication).

[0267] Therefore, in the eighth embodiment, attention is focused on the rotational frequency component Tc of the motor (55) of the compression torque signal, which decreases in conjunction with a sealing failure caused by a decrease in the amount of lubricating oil sealing the compression chamber (61), and the rotational frequency component Tc of the motor (55) of the compression torque signal is used to determine the presence or absence of signs of a failure of the drive shaft (80) and the first to third bearings (79, 69, 93). By doing so, after a decrease in the amount of oil in the oil reservoir (95), which is a cause of a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), can be detected as a sign of a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged, and a failure can be predicted.

[0268] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the eighth embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment. Furthermore, the rotation frequency component Tc of the motor (55) of the compression torque signal changes in accordance with the change in the amount of seal oil in the compression chamber (61), but is not affected by friction between the drive shaft (55) and the first to third bearings (79, 69, 93). Therefore, the rotation frequency component Tc of the motor (55) of the compression torque signal is easy to detect a deterioration in the sealing performance of the compression chamber (61), and the accuracy of prediction is improved by detecting the rotation frequency component Tc of the motor (55) of the compression torque signal as an index of the deterioration in the sealing performance of the compression chamber (61).

[0269] In the eighth embodiment, the rotation frequency component Tc of the motor (55) of the compression torque signal has been described as an example of the index Tc indicating the waveform of the compression torque, but the index Tc indicating the waveform of the compression torque is not limited to this. For example, the index Tc indicating the waveform of the compression torque may be obtained by integrating, for one rotation of the motor (55), the absolute value of the difference ((Tinst-Tavg) / Tavg) obtained by subtracting the average value Tavg of the compression torque for one rotation of the motor (55) from the instantaneous value Tinst of the compression torque signal, and dividing the difference by the average value Tavg of the compression torque for one rotation of the motor (55). Like the rotation frequency component Tc of the motor (55) of the compression torque signal, this value also decreases when the amount of lubricating oil sealing the compression chamber (61) decreases, compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without insufficient lubrication).

[0270] -Modification 1 of embodiment 8- Modification 1 is an embodiment in which the predictive condition is changed from that of embodiment 8. In Modification 1, the predictive condition is that the rate of decrease Tcr ((Tc-Tcn) / Tcn) of the rotational frequency component Tc of the motor (55) of the compression torque signal with respect to a predetermined normal value Tcn is equal to or greater than a reference value Tcb (for example, 0.1 (10%)) (Tcr≧Tcb).

[0271] The failure prediction unit (23) obtains the rotation frequency component Tc of the compression torque signal of the motor (55) in the same manner as in the eighth embodiment, and then calculates a decrease rate Tcr of the rotation frequency component Tc of the compression torque signal with respect to a predetermined normal value Tcn of the motor (55). The failure prediction unit (23) calculates the decrease rate Tcr by subtracting the normal value Tcn from the rotation frequency component Tc of the motor (55) of the compression torque signal and dividing the result by the normal value Tcn. Then, the failure prediction unit (23) compares the calculated increase rate Tcr with a judgment reference value Tcb, and determines that a prediction condition is established when the decrease rate Tcr is equal to or greater than the judgment reference value Tcb (Tcr≧Tcb).

[0272] As described above, in the determination operation, even if the object to be compared with the determination reference value Tcb is the rate of decrease Tcr ((Tc-Tcn) / Tcn) of the rotational frequency component Tc of the motor (55) of the compression torque signal with respect to a predetermined normal value Tcn, the same effect as in the eighth embodiment can be achieved.

[0273] -Modification 2 of embodiment 8- The second modification is an embodiment in which the predictive condition is changed from that of the eighth embodiment. In the second modification, a motor torque signal is used as the predictive condition instead of the compression torque signal used in the eighth embodiment. That is, in the second modification, the predictive condition is that the amount of decrease ΔTc (Tcn-Tc) of the rotation frequency component Tc of the motor (55) of a signal (motor torque signal) indicating the output torque of the motor (55) from a predetermined normal value Tcn is equal to or greater than a judgment reference value Tcb (ΔTc≧Tcb). Note that the judgment operation is similar to that of the eighth embodiment except that the failure prediction unit (23) calculates, instead of the compression torque, the output torque of the motor (55) while the compressor (50) is performing each of the suction, compression, and discharge steps, and obtains the rotation frequency component Tc of the motor (55) of the signal (motor torque signal) indicating the output torque of the motor (55) for use in the judgment. Note that the output torque of the motor (55) can be estimated by various well-known techniques.

[0274] When the amount of lubricating oil sealing the compression chamber (61) decreases and the sealing performance of the compression chamber (61) deteriorates, causing refrigerant leakage, the output torque of the motor (55) changes in the same manner as the compression torque. When refrigerant leakage occurs, the internal pressure of the low-pressure compression chamber (61) decreases compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without poor lubrication), and the rotation frequency component Tc of the motor (55) of the motor torque signal also decreases. Therefore, even if the determination operation is performed based on a predictive condition using the motor torque signal instead of the compression torque signal, the same effect as in the eighth embodiment can be achieved.

[0275] 《Embodiment 9》 The air conditioner (10) of the ninth embodiment is the same as the air conditioner (10) of the first embodiment, except that a vibration sensor (118) that detects vibrations of the compressor (50) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation of the failure prediction unit (23) is changed. The other configurations and operations are the same as those of the first embodiment. Here, the differences from the first embodiment will be described.

[0276] <Vibration sensor> 10, the vibration sensor (118) is attached to the compressor (50) so as to detect vibration of the compressor (50). The vibration sensor (118) detects vibration of the compressor (50), converts the detected vibration into an electric signal (vibration signal), and outputs the electric signal to the main controller (21).

[0277] <Judgment operation> The determination operation of the failure prediction unit (23) will be described. In the present embodiment as well, the failure prediction unit (23) repeatedly performs a determination operation for determining whether a predictive condition is satisfied at predetermined time intervals (e.g., every 30 seconds). In the present embodiment, the predictive condition is a condition that a decrease amount ΔVi (Vi-Vin) of an index Vi indicating a waveform of a signal (vibration signal) indicating vibration of the compressor (50) from a predetermined normal value Vin is equal to or greater than a determination reference value Vib (ΔVi≧Vib). Note that in the ninth embodiment, an example will be described in which the rotation frequency component Vi of the motor (55) of the vibration signal is used as the index Vi indicating the waveform of the vibration signal.

[0278] First, the failure prediction unit (23) obtains the rotation frequency component Vi of the motor (55) of the vibration signal (detection signal transmitted from the vibration sensor (118)).

[0279] Next, the failure prediction unit (23) calculates a decrease amount ΔVi of the rotation frequency component Vi of the motor (55) of the vibration signal with respect to a predetermined normal value Vin. The normal value Vin is a rotation frequency component of the motor (55) of the vibration signal in a normal state where the sliding parts of the compressor (50) are not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value Vin. The failure prediction unit (23) calculates the decrease amount ΔVi by subtracting the normal value Vin from the rotation frequency component Vi of the motor (55) of the vibration signal. The normal value Vin may be a value determined in advance for each type of compressor (50). Alternatively, a trial run may be performed after the compressor system (40) is installed to determine the rotation frequency component of the motor (55) of the vibration signal in a normal state where the sliding parts of the compressor (50) are not insufficiently lubricated, and the determined value may be set as the normal value Vin. The normal value Vin is determined for each operating condition of the compressor (50), which is the rotation speed, high pressure, and low pressure.

[0280] Next, the failure prediction unit (23) compares the calculated decrease amount ΔVi with a judgment reference value Vib. The failure prediction unit (23) stores a reference value as the judgment reference value Vib. The failure prediction unit (23) determines that the predictive condition is satisfied when the decrease amount ΔVi is equal to or greater than the judgment reference value Vib (ΔVi≧Vib). In other words, the failure prediction unit (23) of the present embodiment determines that the predictive condition is satisfied when the decrease amount ΔVi becomes equal to or greater than the judgment reference value Vib for the first time.

[0281] As described above, in the ninth embodiment, the failure prediction section (23) obtains the rotation frequency component Vi of the motor (55) of the vibration signal, and determines whether or not the predictive condition is satisfied (whether or not there is a predictive condition of failure in the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the rotation frequency component Vi of the motor (55) of the vibration signal. Note that in the ninth embodiment, the rotation frequency component Vi of the motor (55) of the vibration signal (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of lubricating oil sealing the compression chamber (61), is used as the predictive condition for the following reasons.

[0282] In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubrication state of each sliding part of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) changes from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) come into contact with each other and wear, and eventually the drive shaft (80) and the first to third bearings (79, 69, 93) break down (become inoperable) due to seizure or the like. Meanwhile, in the compression section (60), the amount of lubricating oil sealing the compression chamber (61) decreases before the lubrication state of each sliding part changes from fluid lubrication to mixed lubrication or boundary lubrication. When the amount of lubricating oil sealing the compression chamber (61) decreases, the sealing performance of the compression chamber (61) decreases, causing refrigerant leakage, that is, leakage of refrigerant from the compression chamber (61) with a higher internal pressure to the compression chamber (61) with a lower internal pressure.

[0283] When refrigerant leakage occurs, the internal pressure waveform indicating the fluctuation of the internal pressure of the compression chamber (61) changes, and the gas load (the load that the pressure of the gas refrigerant exerts on the orbiting-side wrap (76)) changes. This changes the waveform of a signal (compression torque signal) indicating the compression torque of the compressor (50), which is expressed as the sum of the products of the "tangential component of the gas load" of each compression chamber (61) and the "distance between the center of rotation and the center of gravity of the compression chamber (61)". Since the waveform of the compression torque signal and the waveform of the vibration signal are linked, when refrigerant leakage occurs, the rotation frequency component Vi of the motor (55) of the vibration signal (index Vi indicating the waveform of the vibration signal) decreases.

[0284] Therefore, in the ninth embodiment, attention is focused on the rotational frequency component Vi of the motor (55) of the vibration signal, which decreases in conjunction with a sealing failure caused by a decrease in the amount of lubricating oil sealing the compression chamber (61), and the rotational frequency component Vi of the motor (55) of the vibration signal is used to determine whether or not there are signs of a failure of the drive shaft (80) and the first to third bearings (79, 69, 93). By using this rotational frequency component Vi of the motor (55) of the vibration signal to determine whether or not there are signs of a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after a decrease in the amount of oil in the oil reservoir (95), which may cause a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), the signs of a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected and a failure can be predicted before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

[0285] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the ninth embodiment also provide the same effects as those of the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment. Furthermore, the rotation frequency component Vi of the motor (55) of the vibration signal changes in accordance with the change in the amount of seal oil in the compression chamber (61), but is not affected by friction between the drive shaft (55) and the first to third bearings (79, 69, 93). Therefore, the rotation frequency component Vi of the motor (55) of the vibration signal is easy to detect a deterioration in the sealing performance of the compression chamber (61), and the accuracy of prediction is improved by detecting the rotation frequency component Vi of the motor (55) of the vibration signal as an index of the deterioration in the sealing performance of the compression chamber (61).

[0286] In the ninth embodiment, the rotation frequency component Vi of the motor (55) of the vibration signal has been described as an example of the index Vi indicating the waveform of the vibration signal, but the index Vi indicating the waveform of the vibration signal is not limited to this. For example, the index Vi indicating the waveform of the vibration signal may be obtained by integrating, for one rotation of the motor (55), the absolute value of the difference between the instantaneous value Vinst of the vibration signal and the average value Vavg of the vibration of the compressor (50) for one rotation of the motor (55), divided by the average value Vavg of the vibration for one rotation of the motor (55). Like the rotation frequency component Vi of the motor (55) of the vibration signal, this value also decreases when the amount of lubricating oil sealing the compression chamber (61) decreases, compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without insufficient lubrication).

[0287] -Modification 1 of the 9th embodiment- In the first modification, the predictive condition is changed from that in the ninth embodiment. In the first modification, the predictive condition is that the rate of decrease Vir ((Vi-Vin) / Vin) of the rotational frequency component Vi of the motor (55) of the vibration signal with respect to a predetermined normal value Vin is equal to or greater than a reference value Vib (for example, 0.1 (10%)) (Vir≧Vib).

[0288] The failure prediction unit (23) obtains the rotation frequency component Vi of the motor (55) of the vibration signal in the same manner as in the ninth embodiment, and then calculates a decrease rate Vir of the rotation frequency component Vi of the motor (55) of the vibration signal with respect to a predetermined normal value Vin. The failure prediction unit (23) calculates the decrease rate Vir by subtracting the normal value Vin from the rotation frequency component Vi of the motor (55) of the vibration signal and dividing the result by the normal value Vin. Then, the failure prediction unit (23) compares the calculated decrease rate Vir with a judgment reference value Vib, and determines that a prediction condition is established when the decrease rate Vir is equal to or greater than the judgment reference value Vib (Vir≧Vib).

[0289] As described above, in the judgment operation, even if the object to be compared with the judgment reference value Vib is the decrease rate Vir ((Vi-Vin) / Vin) of the rotational frequency component Vi of the motor (55) of the vibration signal relative to a predetermined normal value Vin, the same effect as in the ninth embodiment can be achieved.

[0290] -Modification 2 of embodiment 9- In the air conditioner (10) of the ninth embodiment, a microphone (119) is provided to detect sound (air vibrations) generated during operation of the compressor (50), instead of the vibration sensor (118) for detecting vibrations Vi of the compressor (50). The rotational frequency component Vi of a detection signal (vibration signal) by the microphone (119) is used as the predictive condition.

[0291] 11, the microphone (119) is provided at a position where it can detect sound generated by the compressor (50) while the compressor (50) is in operation. The microphone (119) detects sound generated by the compressor (50) while the compressor (50) is in operation, converts the detected sound into an electric signal (vibration signal), and outputs the electric signal to the main controller (21).

[0292] The determination operation differs from that of the ninth embodiment only in that the vibration signal is a detection signal transmitted from the microphone (119). Since the other determination operations are the same as those of the ninth embodiment, detailed description thereof will be omitted.

[0293] As described above, in the air conditioner (10) of the ninth embodiment, even if the microphone (119) is provided instead of the vibration sensor (118) and the rotational frequency component Vi of the detection signal (vibration signal) by the microphone (119) is used as the predictive condition, the same effects as those of the ninth embodiment can be achieved.

[0294] Tenth Embodiment The air conditioner (10) of the tenth embodiment is the same as the air conditioner (10) of the first embodiment, except that the drive shaft (80) and the first, second, and third bearings (79, 69, 93) are made of metallic materials, and a current detection unit (116) is provided to detect an input current (hereinafter simply referred to as motor drive current) for driving the motor (55) instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation of the failure prediction unit (23) is changed. The rest of the configuration and operation are the same as those of the first embodiment. Here, the differences from the first embodiment will be described.

[0295] Current detection section As in the seventh embodiment shown in FIG. 8, the current detection unit (116) is provided in the electric wires (three windings (U-phase, V-phase, and W-phase windings) of the motor (55)) connecting the motor drive device (45) and the compressor (50), and detects three-phase currents (U-phase current (iu), V-phase current (iv), and W-phase current (iw)). The current detection unit (116) outputs the detected three-phase currents to the main controller (21). It is not essential to provide the current detection unit (116), and the three-phase currents (iu, iv, iw) may be derived from the switching pattern and the DC current detected by a shunt resistor (not shown) provided in a DC section (not shown) of the motor drive device (45).

[0296] <Judgment operation> The determination operation of the failure prediction unit (23) will be described. In the present embodiment as well, the failure prediction unit (23) repeatedly performs a determination operation for determining whether a predictive condition is satisfied at predetermined time intervals (e.g., every 30 seconds). In the present embodiment, the predictive condition is a condition that an increase ΔIh (Ih-Ihn) of a predetermined high-frequency component Ih of a motor drive current (any of the three-phase currents (iu, iv, iw) detected by the current detection unit (116)) from a predetermined normal value Ihn is equal to or greater than a determination reference value Ihb (ΔIh≧Ihb).

[0297] First, the failure prediction unit (23) obtains a predetermined high-frequency component Ih of the motor drive current (one of the three-phase currents (iu, iv, iw) detected by the current detection unit (116). The failure prediction unit (23) performs a fast Fourier transform on one of the three-phase currents (iu, iv, iw) detected by the current detection unit (116), and determines a component that is a predetermined multiple of the rotational frequency of the motor (55) from among a plurality of resolved frequency components as the predetermined high-frequency component Ih of the motor drive current.

[0298] Next, the failure prediction unit (23) calculates an increase ΔIh of the predetermined high-frequency component Ih of the motor drive current with respect to a predetermined normal value Ihn. The normal value Ihn is a predetermined high-frequency component of the motor drive current in a normal state in which each sliding part of the compressor (50) is not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value Ihn. The failure prediction unit (23) calculates the increase ΔIh by subtracting the normal value Ihn from the predetermined high-frequency component Ih of the motor drive current. The normal value Ihn may be a value determined in advance for each type of compressor (50). Alternatively, a trial run may be performed after the compressor system (40) is installed to determine the predetermined high-frequency component of the motor drive current in a normal state in which the bearings (79, 69, 93) are not deteriorated, and the determined value may be the normal value Ihn. The normal value Ihn is determined for each operating condition of the compressor (50), which is the rotation speed, high pressure, and low pressure.

[0299] Next, the failure prediction unit (23) compares the calculated increase amount ΔIh with a judgment reference value Ihb. The failure prediction unit (23) stores a reference value as the judgment reference value Ihb. The failure prediction unit (23) determines that the predictive condition is met when the increase amount ΔIh is equal to or greater than the judgment reference value Ihb (ΔIh≧Ihb). In other words, the failure prediction unit (23) of the present embodiment determines that the predictive condition is met when the increase amount ΔIh becomes equal to or greater than the judgment reference value Ihb for the first time.

[0300] As described above, in this embodiment 10, the failure prediction unit (23) obtains a predetermined high-frequency component Ih of the motor drive current, and determines whether or not the predictive conditions are met (whether or not there are predictive signs of failure in the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the predetermined high-frequency component Ih of the motor drive current.

[0301] The inventors of the present application have found that when foreign matter, such as wear powder generated by wear of the sliding parts or carbides generated by deterioration of the lubricating oil, is supplied together with lubricating oil to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) made of a metallic material, the predetermined high-frequency component Ih of the motor drive current increases. The inventors have also found that when the drive shaft (80) and the first to third bearings (79, 69, 93) are made of a metallic material, the predetermined high-frequency component Ih of the motor drive current caused by the supply of foreign matter changes compared to when the drive shaft (80) and the first to third bearings (79, 69, 93) are made of another material. Thus, in the tenth embodiment, the predetermined high-frequency component Ih of the motor drive current (an index showing the driving state of the motor (55)) is used as the predictive condition for the following reasons.

[0302] In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubrication state of each sliding part of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) changes from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) come into contact with each other and wear (deteriorate), and eventually the drive shaft (80) and the first to third bearings (79, 69, 93) break down (become inoperable) due to seizure or the like. Meanwhile, in the tenth embodiment, the compressor (50) is also configured such that, when the amount of lubricating oil in the oil reservoir (95) decreases, a sealing failure due to a decrease in the amount of lubricating oil sealing the compression chamber (61) occurs before a lubrication failure of the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93). Therefore, when the amount of lubricating oil in the oil reservoir (95) decreases, the sliding parts of the compression section (60) wear out before the sliding parts of the drive shaft (80) and the first, second, and third bearings (79, 69, 93) wear out. The wear powder (foreign matter) generated in this manner is supplied to the sliding parts of the drive shaft (80) and the first, second, and third bearings (79, 69, 93) together with the lubricating oil.

[0303] Furthermore, when the lubricating oil in the compressor (50) starts to deteriorate, the lubricating oil changes into hard carbides, and the carbides (foreign matter) thus produced are supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) together with the lubricating oil. As the deterioration of the lubricating oil progresses, the drive shaft (80) and the first to third bearings (79, 69, 93) will eventually break down, for example by seizing, as in the case of a decrease in the amount of oil.

[0304] Incidentally, when the first to third bearings (79, 69, 93) are made of a resin material, even if foreign matter such as wear powder and carbide is supplied to the first to third bearings (79, 69, 93), most of the wear powder is embedded in the first to third bearings (79, 69, 93). However, in the tenth embodiment, the first to third bearings (79, 69, 93) are made of a metal material. Therefore, the wear powder is not embedded in the first to third bearings (79, 69, 93) and damages both the drive shaft (80) and the first to third bearings (79, 69, 93) between them (deterioration of the drive shaft (80) and the first to third bearings (79, 69, 93)). As a result, the predetermined high-frequency component Ih of the motor drive current increases compared to the normal state (when the sliding parts of the compressor (50) are in a normal state without insufficient lubrication). Therefore, in the tenth embodiment, attention is focused on a predetermined high-frequency component Ih of the motor drive current, and the predetermined high-frequency component Ih of the motor drive current is used to determine the presence or absence of signs of failure in the drive shaft (80) and the first to third bearings (79, 69, 93). Therefore, after a change in condition within the compressor (50) that will cause a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50) occurs (a decrease in the amount of oil in the oil reservoir (95) if the foreign matter is wear powder, and deterioration of the lubricating oil if the foreign matter is carbide), signs of failure in the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected and a failure can be predicted before the drive shaft (80) and the first to third bearings (79, 69, 93) are damaged.

[0305] In the tenth embodiment, the drive shaft (80) and the first to third bearings (79, 69, 93), which are made of a metallic material, deteriorate (become damaged by wear powder or carbide generated due to an earlier occurrence of poor lubrication in another sliding part) in response to a change in condition inside the compressor (50) that causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) (a decrease in the amount of oil in the oil reservoir (95) if the foreign matter is wear powder, or deterioration of the lubricating oil if the foreign matter is carbide). This causes a change in a predetermined high-frequency component Ih of the motor drive current (an index showing the drive state of the motor (55)). In other words, in the tenth embodiment, the drive shaft (80) and the first to third bearings (79, 69, 93) made of a metallic material are the parts subject to failure prediction, and deteriorate in conjunction with a change in condition within the compressor (50) that is the cause of a failure (a decrease in the amount of oil in the oil reservoir (95) if the foreign matter is wear powder, or deterioration of the lubricating oil if the foreign matter is carbide), and become the manifestation parts that change a predetermined index (a predetermined high-frequency component Ih of the motor drive current) in conjunction with the deterioration.

[0306] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the tenth embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment.

[0307] -Modification 1 of embodiment 10- Modification 1 is an embodiment in which the predictive condition is changed from that of embodiment 10. In modification 1, the predictive condition is that the increase rate Ihr ((Ih-Ihn) / Ihn) of a predetermined high frequency component Ih of the motor drive current with respect to a predetermined normal value Ihn is equal to or greater than a judgment reference value Ihb (e.g., 0.1 (10%)) (Ihr≧Ihb).

[0308] The failure prediction unit (23) obtains a predetermined high frequency component Ih of the motor drive current in the same manner as in embodiment 10, and then calculates an increase rate Ihr of the predetermined high frequency component Ih of the motor drive current with respect to a predetermined normal value Ihn. The failure prediction unit (23) calculates the increase rate Ihr by subtracting the normal value Ihn from the predetermined high frequency component Ih of the motor drive current and dividing the result by the normal value Ihn. The failure prediction unit (23) then compares the calculated increase rate Ihr with a judgment reference value Ihb, and determines that a prediction condition is established when the increase rate Ihr is equal to or greater than the judgment reference value Ihb (Ihr≧Ihb).

[0309] As described above, in the judgment operation, even if the object to be compared with the judgment reference value Ihb is the increase rate Ihr ((Ih-Ihn) / Ihn) of a predetermined high-frequency component Ih of the motor drive current relative to a predetermined normal value Ihn, the same effect as in embodiment 10 can be achieved.

[0310] Eleventh Embodiment The air conditioner (10) of embodiment 11 is the same as the air conditioner (10) of embodiment 1, except that the drive shaft (80) and the first, second, and third bearings (79, 69, 93) are made of metallic materials, and a current detection unit (116) is provided to detect an input current (hereinafter simply referred to as motor drive current) for driving the motor (55) instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation of the failure prediction unit (23) is changed. The other configurations and operations are the same as those of embodiment 1. Here, the differences from embodiment 1 will be described.

[0311] <Current detection section> As in the seventh embodiment shown in FIG. 8, the current detection unit (116) is provided in the electric wires (three windings (U-phase, V-phase, and W-phase windings) of the motor (55)) connecting the motor drive device (45) and the compressor (50), and detects three-phase currents (U-phase current (iu), V-phase current (iv), and W-phase current (iw)). The current detection unit (116) outputs the detected three-phase currents to the main controller (21). It is not essential to provide the current detection unit (116), and the three-phase currents (iu, iv, iw) may be derived from the switching pattern and the DC current detected by a shunt resistor (not shown) provided in a DC section (not shown) of the motor drive device (45).

[0312] <Judgment operation> The determination operation of the failure prediction unit (23) will be described. In the present embodiment as well, the failure prediction unit (23) repeatedly performs a determination operation for determining whether a predictive condition is satisfied at predetermined time intervals (e.g., every 30 seconds). In the present embodiment, the predictive condition is a condition in which an increase ΔIhc (Ihc-Ihcn) of a predetermined harmonic component Ihc of an input current (any of the three-phase currents (iu, iv, iw) detected by the current detection unit (116)) for driving the motor (55) with respect to a predetermined normal value Ihcn is equal to or greater than a determination reference value Ihcb (ΔIhc≧Ihcb).

[0313] First, the failure prediction unit (23) obtains a predetermined harmonic component Ihc of the motor drive current (one of the three-phase currents (iu, iv, iw) detected by the current detection unit (116). The failure prediction unit (23) performs a fast Fourier transform on one of the three-phase currents (iu, iv, iw) detected by the current detection unit (116), and determines a component that is a predetermined multiple of the rotation frequency of the motor (55) from among a plurality of resolved frequency components as the predetermined harmonic component Ihc of the motor drive current.

[0314] Next, the failure prediction unit (23) calculates an increase ΔIch of the predetermined harmonic component Ihc of the motor drive current with respect to a predetermined normal value Ihcn. The normal value Ihcn is a predetermined harmonic component of the motor drive current in a normal state in which the sliding parts of the compressor (50) are not insufficiently lubricated, and the failure prediction unit (23) stores a reference value as the normal value Ihcn. The failure prediction unit (23) calculates the increase ΔIhc by subtracting the normal value Ihcn from the predetermined harmonic component Ihc of the motor drive current. The normal value Ihcn may be a value determined in advance for each type of compressor (50). Alternatively, a trial run may be performed after the compressor system (40) is installed to determine the predetermined harmonic component of the motor drive current in a normal state in which the bearings (79, 69, 93) are not deteriorated, and the determined value may be the normal value Ihcn. The normal value Ihcn is determined for each operating condition of the compressor (50), which is composed of the rotation speed, high pressure, and low pressure.

[0315] Next, the failure prediction unit (23) compares the calculated increase ΔIhc with a judgment reference value Ihcb. The failure prediction unit (23) stores a reference value as the judgment reference value Ihcb. The failure prediction unit (23) determines that the predictive condition is met when the increase ΔIh is equal to or greater than the judgment reference value Ihcb (ΔIhc≧Ihcb). In other words, the failure prediction unit (23) of this embodiment determines that the predictive condition is met when the increase ΔIhc becomes equal to or greater than the judgment reference value Ihcb for the first time.

[0316] As described above, in this embodiment 11, the failure prediction unit (23) obtains a predetermined harmonic component Ihc of the motor drive current, and determines whether or not the predictive condition is satisfied (whether or not there are predictive symptoms of failure in the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the predetermined harmonic component Ihc of the motor drive current.

[0317] The inventors of the present application have found that when the drive shaft (80) and the first, second, and third bearings (79, 69, 93) are made of a metal material, even if poor lubrication occurs in the sliding portions of the drive shaft (80) and the first, second, and third bearings (79, 69, 93), wear is less likely to occur in the sliding portions than when the first, second, and third bearings (79, 69, 93) are made of a resin material. However, once wear occurs, surface roughness (deterioration) immediately occurs, and convex portions caused by the surface roughness slide against each other while coming into contact with each other, thereby increasing a predetermined harmonic component Ihc of the motor drive current. In particular, in a small compressor (50), the value of the motor drive current is small and changes are difficult to detect. However, when the drive shaft (80) and the first, second, and third bearings (79, 69, 93) are made of a metal material, the increase in a specified harmonic component Ihc of the motor drive current caused by protrusions that come into contact and slide against each other due to surface roughness (deterioration) is greater than when the drive shaft (80) and the first, second, and third bearings are made of other materials.

[0318] Therefore, in the eleventh embodiment, this point is taken advantage of by making the drive shaft (80) and the first to third bearings (79, 69, 93) out of a metallic material, and using a predetermined harmonic component Ihc (an index showing the driving state of the motor (55)) of the motor drive current to determine whether or not there are signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93). In this way, after the occurrence of poor lubrication, which is a cause of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), signs of a malfunction of the drive shaft (80) and the first to third bearings (79, 69, 93) can be detected and a malfunction can be predicted before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

[0319] In the eleventh embodiment, the drive shaft (80) and the first to third bearings (79, 69, 93) made of a metallic material deteriorate (become rough on their surfaces) in response to a change in condition (poor lubrication) in the compressor (50), which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93), and change (increase) a predetermined harmonic component Ihc of the motor drive current (an index showing the drive state of the motor (55)). In other words, in the eleventh embodiment, the drive shaft (80) and the first to third bearings (79, 69, 93) made of a metallic material are target parts for failure prediction, and deteriorate (become rough on their surfaces) in response to a change in condition (poor lubrication) in the compressor (50), which causes a failure, and serve as manifesting parts that change the predetermined index (predetermined harmonic component Ihc of the motor drive current) in response to the deterioration.

[0320] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the eleventh embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment.

[0321] -Modification 1 of embodiment 11- Modification 1 is an embodiment in which the predictive condition is changed from that of embodiment 11. In modification 1, the predictive condition is that the increase rate Ihcr ((Ihc-Ihcn) / Ihcn) of a predetermined harmonic component Ihc of the motor drive current with respect to a predetermined normal value Ihcn is equal to or greater than a judgment reference value Ihcb (e.g., 0.1 (10%)) (Ihr≧Ihb).

[0322] The failure prediction unit (23) obtains a predetermined harmonic component Ihc of the motor drive current in the same manner as in the 11th embodiment, and then calculates an increase rate Ihcr of the predetermined harmonic component Ihc of the motor drive current with respect to a predetermined normal value Ihcn. The failure prediction unit (23) calculates the increase rate Ihcr by subtracting the normal value Ihcn from the predetermined harmonic component Ihc of the motor drive current and dividing the result by the normal value Ihcn. The failure prediction unit (23) then compares the calculated increase rate Ihcr with a judgment reference value Ihcb, and determines that a prediction condition is established when the increase rate Ihcr is equal to or greater than the judgment reference value Ihcb (Ihcr≧Ihcb).

[0323] As described above, in the judgment operation, even if the object to be compared with the judgment reference value Ihcb is the increase rate Ihcr ((Ihc-Ihcn) / Ihcn) of a predetermined harmonic component Ihc of the motor drive current relative to a predetermined normal value Ihcn, the same effect as in embodiment 11 can be achieved.

[0324] -Modification 2 of embodiment 11- In Modification 2, the material of the first to third bearings (79, 69, 93) is changed from that of Embodiment 11. Specifically, in Modification 2, the first to third bearings (79, 69, 93) are made of a resin material.

[0325] The inventors of the present application have found that, even when cutting is performed on the first to third bearings (79, 69, 93) made of a resin material, the outer peripheral surfaces remain frayed (the numerous protrusions that protrude radially outward and are formed on the outer peripheral surfaces during molding simply bend to avoid the tool during cutting and remain uncut), and therefore, when poor lubrication occurs in the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), the numerous soft protrusions made of resin come into contact with the outer peripheral surface of the drive shaft (80). As a result, a predetermined harmonic component Ihc of the motor drive current increases as compared to the normal state (when the sliding parts of the compressor (50) are in a normal state and not poorly lubricated).

[0326] Therefore, in the second modification, this point is taken advantage of by making the first, second, and third bearings (79, 69, 93) out of a resin material, and a predetermined harmonic component Ihc (an index showing the driving state of the motor (55)) of the motor drive current is used to determine whether or not there are signs of a malfunction of the drive shaft (80) and the first, second, and third bearings (79, 69, 93). In this way, after a decrease in the amount of oil in the oil reservoir (95) occurs, which may cause a malfunction of the drive shaft (80) and the first, second, and third bearings (79, 69, 93) of the compressor (50), the signs of a malfunction of the drive shaft (80) and the first, second, and third bearings (79, 69, 93) can be detected and a malfunction can be predicted before the drive shaft (80) and the first, second, and third bearings (79, 69, 93) are damaged.

[0327] In the second modification, the sliding portions (resin protrusions protruding toward the drive shaft (80)) of the first to third bearings (79, 69, 93) made of a resin material that slide against the drive shaft (80) come into contact with the drive shaft (80) in response to a change in condition (poor lubrication) in the compressor (50), which is a cause of failure of the drive shaft (80) and the first to third bearings (79, 69, 93), and cause a change (increase) in a predetermined harmonic component Ihc (an index showing the driving state of the motor (55)) of the motor driving current. In other words, in the second modification, the sliding portions (resin protrusions protruding toward the drive shaft (80)) of the first to third bearings (79, 69, 93) made of a resin material that slide against the drive shaft (80) are provided in the compressor mechanism unit (100) and serve as an indication unit that changes a predetermined index (a predetermined harmonic component Ihc of the motor drive current) in response to a change in condition (poor lubrication) in the compressor (50), which is a cause of a failure in the target parts for failure prediction (the drive shaft (80) and the first to third bearings (79, 69, 93)).

[0328] As described above, even if the material of the first to third bearings (79, 69, 93) is changed to a resin material, the same effects as those of the eleventh embodiment can be achieved.

[0329] In addition, the inventors of the present application have found that when poor lubrication occurs in the sliding portions of the drive shaft (80) and the first, second, and third bearings (79, 69, 93) and a large number of soft, resin-made protrusions of the first, second, and third bearings (79, 69, 93) come into contact with the outer circumferential surface of the drive shaft (80), the vibration of the compressor (50) and a predetermined harmonic component Ihc of the sound (air vibration) generated during operation of the compressor (50) also increase compared to the normal state (when the sliding portions of the compressor (50) are in a normal state without poor lubrication).

[0330] By utilizing the above-mentioned point, in the above-mentioned second modification, instead of the predetermined harmonic component Ihc of the motor drive current, it is also possible to use the predetermined harmonic component Ihc of the detection signal (vibration signal) of the vibration sensor (118) that detects the vibration of the compressor (50) or the microphone (119) that detects the sound (air vibration) generated during operation of the compressor (50) in order to determine the presence or absence of signs of failure of the drive shaft (80) and the first to third bearings (79, 69, 93).

[0331] 《Embodiment 12》 A twelfth embodiment will be described. The air conditioner (10) of this embodiment is the air conditioner (10) of the first embodiment, except that the oil supply passage (87) is changed. The control system (20) of the air conditioner (10) of this embodiment operates in the same manner as the control system (20) of the first embodiment. Here, the oil supply passage (87) of the compressor (50) of this embodiment will be described.

[0332] <Fuel passage> 12, the oil supply passage (87) also has a main oil supply passage (88) and an auxiliary oil supply passage (89) in the 12th embodiment. The main oil supply passage (88) in the 12th embodiment is configured similarly to the main oil supply passage (88) in the first embodiment, and constitutes a first oil supply passage that guides lubricating oil in the oil reservoir (95) on which the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) acts, to the first to third bearings (79, 69, 93). On the other hand, the auxiliary oil supply passage (89) in the 12th embodiment is configured differently from the auxiliary oil supply passage (89) in the first embodiment.

[0333] Specifically, in the twelfth embodiment, the auxiliary oil supply passage (89) is formed therein by an oil supply hole formed to extend between the shaft upper support portion (65) and the fixed scroll (70) and a cylindrical member extending from the oil reservoir portion (95) to the oil supply hole. The oil supply hole is formed so that one end opens at the lower surface of the shaft upper support portion (65) and the other end opens in the gap between the outer circumferential wall portion (73) of the fixed scroll (70) and the orbiting side end plate portion (77) of the orbiting scroll (75). One end of the cylindrical member opens at the oil reservoir portion (95) and the other end is inserted into the oil supply hole. One end of the cylindrical member serves as an inlet (89a) of the auxiliary oil supply passage (89).

[0334] In the twelfth embodiment, the auxiliary oil supply passage (89) is configured as described above to guide the lubricating oil in the oil reservoir (95) acting on the pressure of the refrigerant discharged from the compression chamber (61) (high pressure) directly to the compression section (60) without passing through the crank chamber (67). The lubricating oil guided to the compression section (60) seals the gap between the fixed scroll (70) and the orbiting scroll (75) (seals the compression chamber (61)). In other words, in the twelfth embodiment, the auxiliary oil supply passage (89) constitutes a second oil supply passage that guides the lubricating oil in the oil reservoir (95) acting on the pressure of the refrigerant discharged from the compression chamber (61) (high pressure) to the compression section (60).

[0335] In the twelfth embodiment, the inlet (89a) of the auxiliary oil supply passage (second oil supply passage) (89) is disposed above the inlet (88a) of the main oil supply passage (first oil supply passage) (88). Therefore, when the amount of lubricating oil in the oil reservoir (95) decreases and the oil level drops, the inlet (89a) of the auxiliary oil supply passage (89) does not reach the lubricating oil before the inlet (88a) of the main oil supply passage (88) does, and the lubricating oil is not supplied to the compression chamber (61) through the auxiliary oil supply passage (89). The compressor (50) of the twelfth embodiment is configured in such a way that, when the amount of lubricating oil in the oil reservoir (95) decreases, a sealing failure due to a decrease in the amount of lubricating oil that seals the compression chamber (61) occurs earlier than a lubrication failure of the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93).

[0336] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the twelfth embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment.

[0337] In particular, in this embodiment 12, by simply dividing the oil supply passage (87) that supplies lubricating oil to the first to third bearings (79, 69, 93) and the compression section (60) into two and changing the heights of the inlets (88a, 89a) of the two oil supply passages (88, 89), it is possible to easily configure a compressor (50) in which, when the amount of lubricating oil in the oil reservoir section (95) decreases, a sealing failure due to a decrease in the amount of lubricating oil sealing the compression chamber (61) occurs earlier than poor lubrication of the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93).

[0338] Thirteenth embodiment A thirteenth embodiment will be described. The air conditioner (10) of this embodiment is the air conditioner (10) of the first embodiment, except that the oil supply passage (87) and the oil reservoir (95) are modified. The control system (20) of the air conditioner (10) of this embodiment operates in the same manner as the control system (20) of the first embodiment. Here, the oil supply passage (87) and the oil reservoir (95) of the compressor (50) of this embodiment will be described.

[0339] <Fuel passage> 13, in the thirteenth embodiment as well, the oil supply passage (87) has a main oil supply passage (88) and an auxiliary oil supply passage (89). The main oil supply passage (88) of the thirteenth embodiment is configured similarly to the main oil supply passage (88) of the first embodiment and constitutes a first oil supply passage that guides lubricating oil in the oil reservoir (95) on which the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) acts, to the first to third bearings (79, 69, 93). On the other hand, the auxiliary oil supply passage (89) of the thirteenth embodiment is configured differently from the auxiliary oil supply passage (89) of the first embodiment.

[0340] Specifically, in the thirteenth embodiment, the auxiliary oil supply passage (89) is formed by an oil supply hole formed to extend between the shaft upper support portion (65) and the fixed scroll (70) and a cylindrical member extending from the oil reservoir portion (95) to the oil supply hole. The oil supply hole is formed so that one end opens at the lower surface of the shaft upper support portion (65) and the other end opens in the gap between the outer circumferential wall portion (73) of the fixed scroll (70) and the orbiting side end plate portion (77) of the orbiting scroll (75). One end of the cylindrical member opens at the oil reservoir portion (95) and the other end is inserted into the oil supply hole. One end of the cylindrical member serves as an inlet (89a) of the auxiliary oil supply passage (89).

[0341] In the thirteenth embodiment, the auxiliary oil supply passage (89) is configured as described above to guide the lubricating oil in the oil reservoir (95) acting on the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) directly to the compression section (60) without passing through the crank chamber (67). The lubricating oil guided to the compression section (60) seals the gap between the fixed scroll (70) and the orbiting scroll (75) (seals the compression chamber (61)). In other words, in the thirteenth embodiment, the auxiliary oil supply passage (89) constitutes a second oil supply passage that guides the lubricating oil in the oil reservoir (95) acting on the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) to the compression section (60).

[0342] <Oil reservoir> In the thirteenth embodiment, the oil reservoir (95) has a main oil reservoir (first oil reservoir) (96) and a secondary oil reservoir (second oil reservoir) (97). The main oil reservoir (96) and the secondary oil reservoir (97) are separated by a partition member (98) extending in the vertical direction. The partition member (98) is a plate-shaped member extending upward from the bottom of the casing (51) to near the lower end of the lower shaft support portion (90), and partitions the oil reservoir (95) into the main oil reservoir (96) and the secondary oil reservoir (97), which are arranged side by side.

[0343] An inlet (88a) of a main oil supply passage (88) is disposed in the main oil reservoir (96), and an inlet (89a) of an auxiliary oil supply passage (89) is disposed in the auxiliary oil reservoir (97). The inlet (88a) of the main oil supply passage (88) and the inlet (89a) of the auxiliary oil supply passage (89) are provided at a height such that, when the oil level of the lubricating oil in the oil reservoir (95) falls below the upper end of the partition member (98), the oil level of the lubricating oil in the auxiliary oil reservoir (97) falls below the inlet (89a) of the auxiliary oil supply passage (89) before the oil level of the lubricating oil in the main oil reservoir (96) falls below the inlet (88a) of the main oil supply passage (88). With this configuration, in the thirteenth embodiment, under operating conditions in which the amount of oil in the oil reservoir (95) decreases, the inlet (89a) of the auxiliary oil supply passage (89) does not reach the oil level before the inlet (88a) of the main oil supply passage (88) does. With this configuration, the compressor (50) of the thirteenth embodiment is configured so that, when the amount of lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of lubricating oil that seals the compression chamber (61) occurs earlier than poor lubrication of the sliding parts of the drive shaft (80) and the first, second, and third bearings (79, 69, 93).

[0344] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the thirteenth embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment.

[0345] In particular, in the thirteenth embodiment, the oil supply passage (87) and the oil reservoir (95) that supply lubricating oil to the first to third bearings (79, 69, 93) and the compression section (60) are divided into two, and the inlets (88a, 89a) of the two oil supply passages (88, 89) are disposed in separate oil reservoirs (96, 97). The inlets (88a, 89a) of the two oil supply passages (88, 89) are disposed at a height such that, when the amount of oil in the oil reservoir (95) decreases, the inlet (89a) of the auxiliary oil supply passage (89) does not reach the oil level before the inlet (88a) of the main oil supply passage (88). According to the thirteenth embodiment, by simply making improvements to the oil supply passage (87) and the oil reservoir (95) in this manner, it is possible to easily configure a compressor (50) in which, when the amount of lubricating oil in the oil reservoir (95) decreases, poor sealing caused by a decrease in the amount of lubricating oil sealing the compression chamber (61) occurs first, rather than poor lubrication of the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93).

[0346] Fourteenth Embodiment A fourteenth embodiment will be described. The air conditioner (10) of the present embodiment is the air conditioner (10) of the first embodiment, except that the oil supply passage (87) is modified. The control system (20) of the air conditioner (10) of the present embodiment operates in the same manner as the control system (20) of the first embodiment. Here, the oil supply passage (87) of the compressor (50) of the present embodiment will be described.

[0347] <Fuel passage> In the fourteenth embodiment, similarly to the first embodiment, the oil supply passage (87) has a main oil supply passage (88) and an auxiliary oil supply passage (89).

[0348] In the fourteenth embodiment, the oil supply passage (87) is configured to supply lubricating oil from the oil reservoir (95) to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) and the compression section (60) at a predetermined oil supply rate.

[0349] The specified oil supply rate is a rate at which, when the amount of lubricating oil in the oil reservoir (95) decreases compared to the normal state in which lubricating oil is constantly supplied to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) and the compression section (60) through the oil supply passage (87), the amount of oil supplied per unit time to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) falls below the required amount of oil supplied per unit time to the compression section (60) before the required amount of oil supplied per unit time to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) falls below the required amount of oil supplied per unit time to prevent poor lubrication at the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93).

[0350] Specifically, for example, it is assumed that the amount of oil required per unit time to prevent poor lubrication at the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) is 3X (cc / min), and the amount of oil required per unit time to seal the compression chamber (61) is 7X (cc / min). For example, it is assumed that the total amount of lubricating oil supplied through the oil supply passage (87) to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) and the compression section (60) is 16X (cc / min). In such a case, the oil supply passage (87) is designed so that the oil supply passage (87) supplies the lubricating oil from the oil reservoir (95) to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) and the compression section (60) at a 1:1 ratio.

[0351] When the amount of lubricating oil in the oil reservoir (95) becomes lower than the normal amount, the lubricating oil is not constantly supplied to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) and the compression section (60) through the oil supply passage (87), and the total amount of lubricating oil supplied to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) and the compression section (60) decreases (for example, from 16X (cc / min) to 8X (cc / min)). When the total amount of supply decreases to 8X (cc / min), the amount of oil supplied to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) and the compression section (60) also decreases similarly to the total amount of oil supply (50% decrease in this example), and each amount of oil supplied becomes 4X (cc / min). At this time, poor lubrication does not occur at the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) because the amount of oil 4X (cc / min) exceeds the required amount of oil 3X (cc / min) necessary to avoid poor lubrication at the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93). On the other hand, in the compression section (60), the amount of oil 4X (cc / min) falls short of the required amount of oil 7X (cc / min) necessary to seal the compression chamber (61), and the compression chamber (61) cannot be sealed.

[0352] In the compressor (50) of embodiment 14, due to this configuration, when the amount of lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of lubricating oil sealing the compression chamber (61) occurs before poor lubrication of the sliding parts of the drive shaft (80) and the first, second, and third bearings (79, 69, 93).

[0353] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the fourteenth embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment.

[0354] In particular, in the fourteenth embodiment, by simply designing the oil supply passage (87) so that the oil supply passage (87) supplies lubricating oil from the oil reservoir (95) to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) and the compression section (60) at a predetermined oil supply rate, it is possible to easily configure the compressor (50) in which, when the amount of lubricating oil in the oil reservoir (95) decreases, a sealing failure occurs first due to a decrease in the amount of lubricating oil sealing the compression chamber (61) rather than a lubrication failure in the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93).

[0355] Fifteenth embodiment A fifteenth embodiment will be described. The air conditioner (10) of the present embodiment is the air conditioner (10) of the first embodiment, except that the residual oil characteristics of the compressor (50) are changed. The control system (20) of the air conditioner (10) of the present embodiment operates in the same manner as the control system (20) of the first embodiment.

[0356] In the fourteenth embodiment, the compressor (50) is configured to have residual oil sliding characteristics such that the time from when the oil supply passage (87) stops supplying lubricating oil to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) to when damage to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) begins is longer than the time from when the oil supply passage (87) stops supplying lubricating oil from the oil reservoir (95) to the compression section (60) to when the compression chamber (61) is no longer sealed by lubricating oil.

[0357] Such residual oil sliding characteristics can be achieved by reducing the surface roughness of the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), by making the first to third bearings (79, 69, 93) out of a soft material such as resin, by making the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) out of a material that reduces sliding friction resistance, etc.

[0358] As described above, the compressor system (40) and the air conditioner (refrigeration unit) (10) of the fifteenth embodiment also provide the same effects as the compressor system (40) and the air conditioner (refrigeration unit) (10) of the first embodiment.

[0359] In particular, in the fifteenth embodiment, even if the amount of oil in the oil reservoir (95) decreases and lubricating oil is no longer supplied to the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) and the compression section (60), the compression chamber (61) is no longer sealed with lubricating oil and an index indicating the operating state of the compression section (60) (such as the discharge gas temperature Tdp) changes before the sliding parts of the drive shaft (80) and the first to third bearings (79, 69, 93) are damaged. Therefore, according to the compressor system (40), after the amount of oil in the oil reservoir (95) decreases, symptoms of a malfunction of the drive shaft (80) and the bearings (79, 69, 93) can be detected and a malfunction can be predicted before the drive shaft (80) and the bearings (79, 69, 93) are damaged due to insufficient lubrication.

[0360] Other Embodiments In the above-described embodiments and modifications, the compressor (50) is a scroll compressor. However, the compressor (50) may be any type of positive displacement compressor, such as a rotary compressor.

[0361] In addition, the main controller (prediction device) (21) may predict a failure of a target part (e.g., the compression section (60)) other than the drive shaft (80) and the first to third bearings (79, 69, 93) and perform an avoidance action to avoid the failure of the target part or notify the outside that there is a warning of a failure.

[0362] In addition, in each of the above-described embodiments and modified examples, the failure prediction unit (23) of the main controller (21) may be configured to execute, as the avoidance action, either “an action of changing the operating state of the compressor (50) from a normal state to a light load state” or “an action of issuing an alert that there are signs of damage to the bearings (79, 69, 93).”

[0363] In addition, in each of the above-described embodiments and modified examples, the main controller (21) constitutes a prediction device equipped with the failure prediction unit (23), but the prediction device is not limited to the main controller (21). For example, a device or system external to the air conditioner (10), such as a server device or a cloud (cloud computing), may be equipped with the failure prediction unit (23) and function as a prediction device that predicts failures by communicating with the main controller (21) via a communication network.

[0364] Although the embodiment and the modified examples have been described above, it will be understood that various modifications of the form and details are possible without departing from the spirit and scope of the claims. In addition, the elements of the above embodiment, modified examples, and other embodiments may be appropriately combined or substituted. [Industrial Applicability]

[0365] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for compressor systems and refrigeration devices. [Explanation of symbols]

[0366] 10 Air conditioners (refrigeration units) 21 Main controller (prediction device) 23 Failure Prediction Department 30 Refrigerant circuit 40 Compressor System 50 Compressor 55 Motor 60 Compression section 61 Compression Chamber 68 Main bearing part (bearing) 78 Boss part (bearing) 80 Drive shaft 82 Main Journal Section 83 Sub-Journal Section 85 Eccentric shaft part 87 Fuel passage 88 Main oil supply passage (No. 1 oil supply passage) 88a entrance 89 Auxiliary oil supply passage (second oil supply passage) 89a entrance 91 Sub-bearing part (bearing) 95 Oil Reservoir 96 Main oil reservoir (first oil reservoir) 97 Secondary oil reservoir (secondary oil reservoir) 98 Partitioning material 100 Compressor mechanism

Claims

1. a compressor (50) including a motor (55), a compression section (60) having a compression chamber (61) for sucking in and compressing a fluid, a drive shaft (80) connected to the motor (55) for driving the compression section (60), and bearings (79, 69, 93) for supporting the drive shaft (80), in which lubricating oil is supplied from a common oil supply source to the compression section (60), and to sliding parts of the drive shaft (80) and the bearings (79, 69, 93); A compressor system comprising: a prediction device (21) for predicting failures of the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50), The prediction device (21) includes a failure prediction unit (23) which predicts failure of the bearing (79, 69, 93) and the drive shaft (80) based on a change in an index showing a deterioration in the sealing performance of the compression chamber (61). A compressor system comprising:

2. 2. The compressor system of claim 1, The index is the internal pressure of the compression chamber (61). A compressor system comprising:

3. 2. The compressor system of claim 1, The index is a polytropic index in the compression process of the compression chamber (61). A compressor system comprising:

4. 2. The compressor system of claim 1, The index is the temperature of the gas discharged from the compression section (60). A compressor system comprising:

5. 2. The compressor system of claim 1, The index is the amount of work done by the compressor (50) or the amount of power input to the motor (55). A compressor system comprising:

6. 2. The compressor system of claim 1, The index is the refrigeration capacity of the refrigeration system (10) including the compressor (50). A compressor system comprising:

7. 2. The compressor system of claim 1, The indicator is the waveform of the compression torque of the compressor (50). A compressor system comprising:

8. 2. The compressor system of claim 1, The indicator is a waveform of a motor signal that is correlated with at least one of the voltage, current, and power of the motor (55). A compressor system comprising:

9. 2. The compressor system of claim 1, The indicator is a waveform of a vibration signal indicating the intensity of vibration of the compressor (50) or the intensity of sound generated in the compressor (50). A compressor system comprising:

10. 2. The compressor system of claim 1, The compressor (50) is formed with an oil reservoir (95) serving as the oil supply source for storing lubricating oil to be supplied to the compression section (60) and sliding parts of the drive shaft (80) and the bearings (79, 69, 93), When the amount of lubricating oil in the oil reservoir (95) of the compressor (50) decreases, the amount of lubricating oil sealing the compression chamber (61) decreases before insufficient lubrication occurs in the sliding parts of the drive shaft (80) and the bearings (79, 69, 93). A compressor system comprising:

11. The compressor system of claim 10, The oil reservoir (95) is formed at the bottom of the compressor (50) so that the pressure of the high-pressure discharge gas discharged from the compression chamber (61) acts on the oil reservoir (95). The compressor (50) includes a first oil supply passage (88) that guides lubricating oil in the oil sump (95) to sliding portions of the drive shaft (80) and the bearings (79, 69, 93), and a second oil supply passage (89) that guides the lubricating oil in the oil sump (95) to the compression section (60), The inlet (89a) of the second oil supply passage (89) is disposed above the inlet (88a) of the first oil supply passage (88). A compressor system comprising:

12. The compressor system of claim 10, the compressor (50) includes an oil supply passage (87) that guides lubricating oil from the oil reservoir (95) to the compression section (60), the drive shaft (80), and sliding parts of the bearings (79, 69, 93); the oil supply passage (87) is configured to supply the lubricating oil from the oil reservoir (95) to the compression section (60), the drive shaft (80), and sliding parts of the bearings (79, 69, 93) at a predetermined oil supply rate; The above-mentioned predetermined refueling rate is: When the amount of lubricating oil in the oil reservoir (95) becomes lower than the normal amount in which lubricating oil is constantly supplied to the compression section (60), the drive shaft (80), and the sliding parts of the bearings (79, 69, 93) through the oil supply passage (87), a rate at which the amount of oil supplied to the compression section (60) falls below the amount of oil required to seal the compression chamber (61) before the amount of oil supplied to the sliding parts of the drive shaft (80) and the bearings (79, 69, 93) falls below the amount of oil required to avoid poor lubrication at the sliding parts of the drive shaft (80) and the bearings (79, 69, 93). A compressor system comprising:

13. The compressor system of claim 10, The oil reservoir (95) is formed at the bottom of the compressor (50) so that the pressure of the high-pressure discharge gas discharged from the compression chamber (61) acts on the oil reservoir (95). The compressor (50) includes a first oil supply passage (88) that guides lubricating oil in the oil sump (95) to sliding portions of the drive shaft (80) and the bearings (79, 69, 93), and a second oil supply passage (89) that guides the lubricating oil in the oil sump (95) to the compression section (60), The oil reservoir (95) is provided with a partition member (98) separating a first oil reservoir (96) in which an inlet (88a) of the first oil supply passage (88) is disposed and a second oil reservoir (97) in which an inlet (89a) of the second oil supply passage (89) is disposed, The inlet (88a) of the first oil supply passage (88) and the inlet (89a) of the second oil supply passage (89) are provided at a height such that, when the oil level of the lubricating oil in the oil reservoir (95) falls below an upper end of the partition member (98), the oil level of the lubricating oil in the second oil reservoir (97) falls below the inlet (89a) of the second oil supply passage (89) before the oil level of the lubricating oil in the first oil reservoir (96) falls below the inlet (88a) of the first oil supply passage (88). A compressor system comprising:

14. 11. The compressor system of claim 10, the compressor (50) includes an oil supply passage (87) that guides lubricating oil from the oil reservoir (95) to the compression section (60), the drive shaft (80), and sliding parts of the bearings (79, 69, 93); The compressor (50) The time from when the lubricating oil is no longer supplied to the compression section (60) through the oil supply passage (87) to when the compression chamber (61) is no longer sealed with the lubricating oil is The oil supply passage (87) is configured to have residual oil sliding characteristics such that the time from when the lubricating oil is no longer supplied to the sliding portions of the drive shaft (80) and the bearings (79, 69, 93) through the oil supply passage (87) until the bearings (79, 69, 93) and the drive shaft (80) start to be damaged is longer. A compressor system comprising:

15. a compressor (50) including a motor (55), a compression section (60) having a compression chamber (61) for sucking in and compressing a fluid, a drive shaft (80) connected to the motor (55) for driving the compression section (60), and bearings (79, 69, 93) for supporting the drive shaft (80); A compressor system comprising: a prediction device (21) for predicting failures of the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50), The bearings (79, 69, 93) and the drive shaft (80) each have a sliding portion made of a metal material. The prediction device (21) includes a failure prediction unit (23) which predicts failure of the bearings (79, 69, 93) and the drive shaft (80) based on a change in an index indicating a driving state of the motor (55). A compressor system comprising:

16. a compressor (50) including a motor (55), a compression section (60) having a compression chamber (61) for sucking in and compressing a fluid, a drive shaft (80) connected to the motor (55) for driving the compression section (60), and bearings (79, 69, 93) for supporting the drive shaft (80); A compressor system comprising: a prediction device (21) for predicting failures of the bearings (79, 69, 93) and the drive shaft (80) of the compressor (50), a sliding portion of the bearing (79, 69, 93) which slides against the drive shaft (80) is made of a resin material and has a protrusion protruding toward the drive shaft (80); The prediction device (21) includes a failure prediction unit (23) that predicts failure of the bearings (79, 69, 93) and the drive shaft (80) based on a change in an index indicating a driving state of the motor (55) that changes in conjunction with contact of the protrusion with the drive shaft (80). A compressor system comprising:

17. A compressor system comprising: a compressor (50); and a prediction device (21) for predicting a failure of a target part of the compressor (50), The compressor (50) A motor (55); a compressor mechanism section (100) including a compression section (60) having a compression chamber (61) for sucking in and compressing a fluid, a drive shaft (80) connected to the motor (55) for driving the compression section (60), bearings (79, 69, 93) for supporting the drive shaft (80), and an oil supply passage (87) for introducing lubricating oil to the compression section (60) and sliding portions of the drive shaft (80) and the bearings (79, 69, 93); an indication unit that is provided in the compressor mechanism unit (100) and changes a predetermined indicator in response to a state change in the compressor (50) that is a cause of a failure of the target part, The prediction device (21) includes a failure prediction section (23) that predicts a failure of the target part based on a change in the predetermined index. A compressor system comprising:

18. 20. The compressor system of claim 17, the target portion is at least one of the compression portion (60), the drive shaft (80), and the bearings (79, 69, 93), the manifestation unit changes a state of a non-target part different from the target part prior to the change in state of the target part in response to a change in state in the compressor (50) that is a cause of a failure of the target part, The predetermined index changes in conjunction with a change in state of the non-target portion. A compressor system comprising:

19. A compressor system (40) according to any one of claims 1 to 18; a refrigeration system comprising a refrigerant circuit (30) to which the compressor (50) of the compressor system (40) is connected and which circulates refrigerant to perform a refrigeration cycle.

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