JP5579149B2 - Hermetic compressor, refrigeration cycle apparatus including the hermetic compressor, and air conditioner including the refrigeration cycle apparatus - Google Patents

Description

  The present invention relates to a hermetic compressor, a refrigeration cycle apparatus including the hermetic compressor, and an air conditioner including the refrigeration cycle apparatus.

  In general, it is known that when a permanent magnet is exposed to a strong demagnetizing field in a high temperature state, the magnetization direction is reversed and demagnetization, that is, a phenomenon in which the magnetic force is weakened occurs.

  In a permanent magnet type motor with a permanent magnet built into the rotor core, the demagnetizing field applied to the permanent magnet increases as the stator winding current increases. When the winding current exceeds a certain value, it decreases rapidly. Magnetic susceptibility increases. This phenomenon is more likely to occur as the temperature of the permanent magnet increases.If irreversible demagnetization occurs in which the magnetic force does not recover even if the temperature of the permanent magnet is returned to room temperature after the demagnetization rate has once increased, the performance as a motor is reduced. It will deteriorate significantly. Hereinafter, the demagnetization caused by the temperature rise of the permanent magnet is referred to as “high temperature demagnetization”.

  Conventionally, in a refrigeration apparatus having a discharge gas thermistor for detecting the discharge gas temperature of a compressor and a liquid injection mechanism capable of directly injecting liquid refrigerant in a refrigeration cycle to a compressor, the electric motor used for the compressor is provided. By controlling the amount of liquid injection that injects liquid refrigerant in the refrigeration cycle into the compressor so that the magnetic force of the permanent magnet does not begin to decrease, the discharge gas temperature of the compressor is decreased and the temperature of the permanent magnet increases. Has been disclosed to suppress the deterioration of the magnetic properties of the permanent magnet, that is, to suppress the high temperature demagnetization of the permanent magnet (for example, Patent Document 1).

JP 2008-136329 A

  However, since the hermetic compressor generally uses a through hole provided in the rotor core as a refrigerant flow path, even if the above-described conventional technique is applied, the permanent magnet incorporated in the rotor core does not replace the rotor core. It is only indirectly cooled through the electromagnetic steel sheet to be formed, and the permanent magnet cannot be efficiently cooled, and there is a problem that the effect of suppressing the high temperature demagnetization of the permanent magnet is small.

  This invention is made | formed in view of the above, Comprising: It aims at providing the hermetic compressor which can raise the inhibitory effect of the high temperature demagnetization of the permanent magnet integrated in the rotor core.

In order to solve the above-described problems and achieve the object, a hermetic compressor according to the present invention is provided with a motor installed in a cylindrical sealed container whose top and bottom are closed, and the motor in the sealed container. A hermetic compressor including a compression mechanism driven by the electric motor, wherein the rotor of the electric motor includes an electromagnetic wave in which a plurality of magnet insertion holes are provided at equiangular intervals along the circumferential outer periphery. A rotor core formed by laminating a plurality of steel plates, a plurality of permanent magnets that are alternately inserted into adjacent magnet insertion holes to form magnetic poles, and the rotor core is sandwiched in the axial direction, and the permanent magnet and a end plate for securing axially, the plurality of the magnet insertion holes, upon insertion of the permanent magnets is formed so as voids generated in the circumferential ends of the magnet insertion hole, said end Plates are next to each other It notched corresponding to each magnetic pole The inter peripheral position including a circumferential end of the permanent magnet, the gaps refrigerant which comprises using as the refrigerant flow path for flowing.

  According to the present invention, there is an effect that the effect of suppressing the high temperature demagnetization of the permanent magnet incorporated in the rotor core can be enhanced.

FIG. 1 is a longitudinal sectional view of a hermetic compressor according to an embodiment. FIG. 2 is a side view of the rotor in the embodiment. 3 is a cross-sectional view of the rotor shown in FIG. FIG. 4 is an enlarged view of a portion between the magnetic poles of the rotor shown in FIG. FIG. 5 is a diagram showing an example of the shape of the end plate in the embodiment. FIG. 6 is a view of the rotor in the embodiment as viewed in the axial direction. FIG. 7 is a view showing one shape example of the end plate different from the example shown in FIG. FIG. 8 is a diagram illustrating a configuration example of the refrigeration cycle apparatus according to the embodiment. FIG. 9 is a diagram for explaining the effectiveness of the air gap shown in FIG. FIG. 10 is a diagram illustrating an example in which a gap is further provided on the outer peripheral surface of the magnet insertion hole. FIG. 11 is a diagram illustrating an example in which a gap is further provided on the shaft-side surface of the magnet insertion hole. FIG. 12 is a diagram showing the relationship between the winding current of the stator and the demagnetization factor. FIG. 13 is a diagram showing temperature characteristics with respect to the Dy content.

  Hereinafter, a hermetic compressor according to an embodiment of the present invention, a refrigeration cycle apparatus including the hermetic compressor, and an air conditioner including the refrigeration cycle apparatus will be described with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

Embodiment.
FIG. 1 is a longitudinal sectional view of a hermetic compressor according to an embodiment. As shown in FIG. 1, a hermetic compressor 11 according to an embodiment is driven by an electric motor 21 and an electric motor 21 inside a hermetic container 19 whose bottom opening is cylindrical and whose upper opening is closed by a lid. The refrigerating machine oil (not shown) that lubricates mainly the sliding part (not shown) of the compression mechanism 20 is stored in the bottom of the sealed container 19.

  The electric motor 21 includes a stator 22 fixed to the upper portion of the hermetic container 2, and a rotor 1 having a shaft 2 inserted and fixed at the center and rotatably disposed on the inner peripheral surface of the stator 22. .

  FIG. 2 is a side view of the rotor in the embodiment. FIG. 3 is a cross-sectional view of the rotor shown in FIG.

  As shown in FIG. 2 and FIG. 3, the rotor 1 is formed by punching a thin plate (for example, about 0.1 to 1.0 mm) of electromagnetic steel sheet into a predetermined shape with a die and laminating a predetermined number (plural sheets). A shaft insertion hole 2a is provided at the center of the formed rotor core 3, and the shaft 2 is inserted and fixed in the shaft insertion hole 2a. Further, in the axial direction on the outer peripheral side of the rotor core 3, a plurality of magnet insertion holes 6 are provided at equiangular intervals along the circumferential outer periphery, and adjacent permanent magnets are provided in the respective magnet insertion holes 6. 5 are inserted with alternating polarities. Further, the rotor core 3 is provided with a plurality of through holes 7 serving as main refrigerant flow paths in the axial direction inside the magnet insertion hole 6. The rotor 1 includes an end plate 4 that sandwiches the stator core 3 in the axial direction and fixes the permanent magnet 5 in the axial direction. The number, position, and shape of the through holes 7 may be other than those shown in FIG.

  FIG. 4 is an enlarged view of a portion between the magnetic poles of the rotor in the embodiment. As shown in FIG. 4, the magnet insertion hole 6 is configured such that when the permanent magnet 5 is inserted, a gap 8 serving as a refrigerant flow path is generated at both circumferential ends 6 a of the magnet insertion hole 6 in the same manner as the through-hole 7. Is formed. In the present embodiment, this gap 8 is used as a refrigerant flow path for the refrigerant to flow therethrough. Thereby, the circumferential direction both ends 5a of the permanent magnet 5 are exposed to the space | gap 8, and it contacts a refrigerant | coolant directly. The permanent magnet 5 is cooled by allowing the low-temperature refrigerant to flow through the gap 8. In the example shown in FIG. 4, the magnet insertion hole 6 is such that the corner on the outer peripheral surface side of the permanent magnet 5 is exposed in the gap 8, and the corner on the shaft side of the permanent magnet 5 is the rotor core 3. It is formed so as to be in contact with the electromagnetic steel sheet forming. The effect of the gap 8 formed in this way has not only the cooling of the permanent magnet 5 but also a secondary effect. This secondary effect will be described later.

  FIG. 5 is a diagram showing an example of the shape of the end plate in the embodiment. Moreover, FIG. 6 is the figure which looked at the rotor in embodiment to the axial direction. As shown in FIGS. 5 and 6, the end plate 4 is processed into a shape that does not block the plurality of through holes 7 and the gaps 8 provided in the rotor core 3. In FIGS. 5 and 6, holes 10 are provided corresponding to the positions of the plurality of through holes 7 provided in the rotor core 3, and the periphery of each magnetic pole portion including the circumferential end 5 a of the adjacent permanent magnet 5. The example which provided the notch 9 corresponding to the position is shown.

  FIG. 7 is a view showing one shape example of the end plate different from the example shown in FIG. As shown in FIG. 7, the end plate 4 may have a hole 10 a having substantially the same shape as the gap 8 corresponding to the position of each gap 8. In this way, even if the permanent magnet 5 is missing, it is possible to prevent the fragments from scattering.

  Next, the configuration and operation of the refrigeration cycle apparatus according to the present embodiment will be described. FIG. 8 is a diagram illustrating a configuration example of the refrigeration cycle apparatus according to the embodiment. Note that the refrigeration cycle apparatus according to the present embodiment shown in FIG. 8 is suitable for use in an air conditioner, for example.

  As shown in FIG. 8, the refrigeration cycle apparatus according to the embodiment includes a hermetic compressor 11, a condenser 12, a decompression device 13, an evaporator 14, a temperature sensor 15, a bypass circuit (liquid injection circuit) according to the embodiment. ) 16 and a control circuit 25. The bypass circuit 16 is configured by connecting a pressure reducing device 17 and an on-off valve 18 in series between a liquid refrigerant discharge port of the condenser 12 and a gas suction port of the hermetic compressor 11. The temperature sensor 15 is provided in the vicinity of the gas discharge port of the hermetic compressor 11 and detects the temperature of the refrigerant flowing through the gas discharge port. The control circuit 25 controls the on-off valve 18 based on the detection result of the temperature sensor 15.

  First, the operation | movement at the time of the normal driving | operation of the refrigerating-cycle apparatus concerning embodiment is demonstrated with reference to FIG.1, FIG.3, FIG.4 and FIG. During normal operation of the refrigeration cycle apparatus, as shown in FIG. 8, the refrigerant circulates in the order of the hermetic compressor 11, the condenser 12, the decompressor 13, and the evaporator 14, and returns to the hermetic compressor 11 again. Cycle.

  The high-temperature and high-pressure refrigerant gas compressed in the hermetic compressor 11 is condensed by exchanging heat with air in the condenser 12 to become a liquid refrigerant. The liquid refrigerant expands in the decompression device 13 to become low-temperature and low-pressure refrigerant gas, evaporates by exchanging heat with air in the evaporator 14, and is compressed again in the hermetic compressor 11 to become high-temperature and high-pressure refrigerant gas.

  Inside the hermetic compressor 11, the refrigerant gas flows along a path indicated by a broken-line arrow in FIG. The low-temperature and low-pressure refrigerant gas sucked from the gas suction port of the hermetic compressor 11 through the refrigerant suction pipe 23 is compressed by the compression mechanism 20 driven by the electric motor 21. The refrigerant gas that has become high temperature and pressure in this manner passes through the plurality of through holes 7 and the gaps 8 of the rotor core 3 described in FIGS. 3 and 4 and is discharged from the gas discharge port via the refrigerant discharge pipe 24. Is done.

  Next, the operation when the temperature of the refrigerant gas discharged from the gas discharge port of the hermetic compressor 11 abnormally rises due to some factor will be described with reference to FIGS. 1, 3, 4 and 8. FIG. In this case, the bypass circuit 16 bypasses between the liquid refrigerant discharge port of the condenser 12 and the gas suction port of the hermetic compressor 11, and the refrigerant is circulated along the path indicated by the solid line arrow in FIG. A low-temperature liquid refrigerant is directly injected into the hermetic compressor 11. Thereby, the refrigerant temperature inside the hermetic compressor 11 rapidly decreases, and the refrigerant whose temperature has decreased passes through the plurality of through holes 7 and the gaps 8 of the rotor core 3. In the present embodiment, when the refrigerant whose temperature has decreased passes through the gap 8, it directly contacts the permanent magnet 5 exposed in the gap 8, so that the permanent magnet 5 can be efficiently cooled.

  More specifically, between the temperature of the permanent magnet 5 embedded in the rotor 1 and the temperature of the refrigerant gas detected by the temperature sensor 15 provided near the gas discharge port of the hermetic compressor 11. Since there is a correlation, a predetermined temperature lower than the upper limit temperature at which the permanent magnet 5 is not demagnetized at high temperature is set in advance as a threshold for the temperature detected by the temperature sensor 15, and the temperature detected by the temperature sensor 15 is the predetermined temperature. The control circuit 25 may control the on-off valve 18 so that the threshold value is not exceeded. Alternatively, the opening / closing valve 18 may be controlled to open when the temperature of the refrigerant gas detected by the temperature sensor 15 exceeds the predetermined temperature described above.

  As described above, in the example shown in FIG. 4, the magnet insertion hole 6 is rotated so that the corner on the outer peripheral surface side of the permanent magnet 5 is exposed and the corner on the shaft side of the permanent magnet 5 is rotated. A gap 8 is formed so as to be in contact with the magnetic steel sheet forming the core 3. The effect of the gap 8 formed in this way has not only the cooling of the permanent magnet 5 but also a secondary effect. Here, a secondary effect of the gap 8 generated as shown in FIG. 4 will be described with reference to FIG. FIG. 9 is a diagram for explaining a secondary effect of the gap shown in FIG.

  Adjacent permanent magnets 5 are arranged so that N poles and S poles alternate, and a magnetic flux is generated in the direction indicated by the solid line arrow in FIG. Since the air gap 8 acts as a magnetic resistance, when the air gap 8 is provided so that both circumferential ends 5a of the permanent magnet 5 are exposed, between the adjacent permanent magnets 5 and between its own N pole and S pole. Leakage magnetic flux generated between them decreases. Therefore, in addition to the effect of cooling the permanent magnet 5 described above, the gap 8 also has an effect of suppressing a decrease in torque force due to the permanent magnet 5.

  On the other hand, as shown in FIG. 9 (b), when there is no gap 8 in which both circumferential ends 5a of the permanent magnet 5 are exposed, the permanent magnets adjacent to each other through the electromagnetic steel sheet forming the rotor core 3 are provided. The leakage magnetic flux indicated by the broken-line arrow in FIG. 9B is generated between the magnets 5 and between its own N pole and S pole, so that the amount of magnetic flux that can be effectively used is reduced and the torque force generated by the permanent magnet 5 is reduced. descend.

  That is, as shown in FIG. 9B, when the gap 8 that exposes both circumferential ends 5a of the permanent magnet 5 is not provided, not only the effect of cooling the permanent magnet 5 described above is obtained, but also the efficiency. Will be worsened.

  Further, as shown in FIG. 9C, when both the outer peripheral side and axial side corners of both ends 5a in the circumferential direction of the permanent magnet 5 are exposed to the gap 8a, the permanent magnet 5 is moved in the circumferential direction (FIG. 9C). There is a risk of movement in the direction of the solid arrow shown in the figure.

  In the present embodiment, as shown in FIG. 9A, the two corners on the axial side of the circumferential both ends 5 a of the permanent magnet 5 are in contact with the electromagnetic steel sheet forming the rotor core 3. Therefore, it also has an effect of preventing the permanent magnet 5 from moving in the circumferential direction.

  FIG. 4 shows an example in which the gap 8 is generated at both circumferential ends 6 a of the magnet insertion hole 6. However, in order to further increase the cooling effect of the permanent magnet 5, the number of gaps is increased or the gap is increased. It is also possible to increase the surface area of the exposed permanent magnet 5. FIG. 10 is a diagram illustrating an example in which a gap is further provided on the outer peripheral surface of the magnet insertion hole. Moreover, FIG. 11 is a figure which shows the example which further provided the space | gap in the surface at the side of the axis of a magnet insertion hole.

  As shown in FIG. 10A, in addition to the gap 8 shown in FIG. 4, when the gap 8b is further provided on the outer peripheral surface of the magnet insertion hole 6, the cooling effect of the permanent magnet 5 is enhanced. However, since the gap 8b interposed between the rotor 1 and the stator (not shown) acts as a magnetic resistance, the magnetic flux passing from the rotor 1 to the stator is hindered. Further, as shown in FIG. 10 (b), since it is necessary to provide the end plate 4 with a hole 10b corresponding to the position of the gap 8b, the outer periphery of the rotor core 3 and the end plate 4 (FIG. 10 (b)) is provided. A thin-walled portion is generated, and press working becomes difficult, and problems such as a decrease in strength occur.

  On the other hand, as shown in FIG. 11A, in addition to the gap 8 shown in FIG. 4, when a gap 8c is further provided on the shaft-side surface of the magnet insertion hole 6, the rotor 1 is moved to the stator. The passing magnetic flux is not obstructed, and a thin portion is not generated on the outer periphery of the rotor core 3 or the end plate 4. Further, as shown in FIG. 11B and FIG. 11C, by maintaining the surface area of the permanent magnet 5 exposed in the gap 8c, by reducing the number of gaps 8c per one magnet insertion hole 6, It is also possible to increase productivity in the press working of the rotor core 3 and the end plate 4.

  As a permanent magnet of an electric motor used in a hermetic compressor of an air conditioner, for example, a rare earth magnet mainly composed of neodymium, iron, and boron is used. However, this rare earth magnet causes high temperature demagnetization. It has easy characteristics.

  FIG. 12 is a diagram showing the relationship between the winding current of the stator and the demagnetization factor. In FIG. 12, the horizontal axis indicates the winding current, and the vertical axis indicates the demagnetization factor. In FIG. 12, the solid line shows a graph when the temperature of the permanent magnet is 50 ° C., the broken line shows the graph when the temperature of the permanent magnet is 100 ° C., and the alternate long and short dash line shows the temperature of the permanent magnet at 150 ° C. The graph in the case of ° C. is shown.

  As shown in FIG. 12, the higher the temperature of the permanent magnet, the smaller the winding current at which demagnetization occurs. Further, when demagnetization starts at a certain current value, the demagnetization rate increases rapidly in the region where the current value is exceeded. When the demagnetization factor increases, the controllability cannot be maintained. Therefore, the guaranteed range of the demagnetization factor must be suppressed to within 1%, for example. The upper limit of the guaranteed range of demagnetization factor is called “critical demagnetization factor”.

  In addition, as another method for preventing demagnetization, there is a method of increasing the thickness of the permanent magnet or increasing the content of dysprosium (Dyprosium: Dy) contained in the permanent magnet. FIG. 13 is a diagram showing temperature characteristics with respect to the Dy content. In FIG. 13, the horizontal axis represents the Dy content, and the vertical axis represents the temperature of the permanent magnet. Further, the graph shown in FIG. 13 shows the temperature characteristics at the critical demagnetization factor (here, 1%).

  As shown in FIG. 13, the higher the Dy content, the higher the temperature at which the critical demagnetization rate is reached. In other words, since the permanent magnet contains a large amount of Dy, it can be used without demagnetization even in a higher temperature environment.

  In the present embodiment, as described with reference to FIGS. 3 to 7 and FIGS. 9 to 12, when the permanent magnet 5 is inserted into the magnet insertion hole 6, voids 8 and 8 c serving as a refrigerant flow path are generated. In this manner, the magnet insertion hole 6 is formed, and a low-temperature refrigerant is passed through the gaps 8 and 8c, whereby the permanent magnet 5 is cooled to suppress high-temperature demagnetization. For this reason, it is possible to suppress the high-temperature demagnetization of the permanent magnet 5 without increasing the thickness of the permanent magnet or increasing the content of Dy, which is a scarce resource and expensive, and decreases the magnetic force when the content is excessively increased. Therefore, it becomes possible to achieve high efficiency and low cost.

  As described above, according to the hermetic compressor of the embodiment, the refrigeration cycle apparatus including the hermetic compressor, and the air conditioner including the refrigeration cycle apparatus, the permanent magnet is inserted into the magnet insertion hole. Since the magnet insertion holes are formed so that gaps are generated at both ends in the circumferential direction of the magnet insertion holes and the gaps are used as refrigerant flow paths for the refrigerant to flow, A bypass circuit that bypasses between the liquid refrigerant discharge port of the compressor and the gas suction port of the hermetic compressor is provided, and when the temperature of the permanent magnet rises abnormally, the low-temperature liquid refrigerant is supplied to the hermetic compressor by the bypass circuit. By directly injecting, the refrigerant whose temperature has decreased passes through the gaps formed at both ends in the circumferential direction of the magnet insertion hole and directly contacts the surface of the permanent magnet exposed in the gaps, so that the permanent magnets can be efficiently cooled. But Come, it is possible to enhance the effect of suppressing the high temperature demagnetization of the permanent magnet.

  In addition, since the air gap generated at both ends in the circumferential direction of the magnet insertion hole acts as a magnetic resistance, the leakage magnetic flux generated between adjacent permanent magnets and between its own N and S poles is reduced, and the A decrease in torque force due to the magnet can be suppressed.

  In addition, the axial corners of both ends of the permanent magnet in contact with the magnetic steel sheet forming the rotor core prevent the permanent magnet embedded in the rotor core from moving in the circumferential direction. can do.

  Also, a shape that is cut out corresponding to the position around each magnetic pole part including the circumferential end of the adjacent permanent magnet so as not to block the plurality of through holes and the gaps provided in the rotor core This prevents the permanent magnets embedded in the rotor core from moving in the axial direction without interfering with the flow of the refrigerant flowing through the through holes and gaps. can do.

  Alternatively, if permanent magnets are missing by providing holes in the end plate that have substantially the same shape as the through-holes and gaps corresponding to the positions of the multiple through-holes and gaps provided in the rotor core However, it is possible to prevent the fragments from scattering.

  In addition, by forming the magnet insertion hole so that a gap is further generated on the shaft side surface of the magnet insertion hole, the magnetic flux passing from the rotor to the stator is not obstructed, and the rotor iron core and the end plate The permanent magnet cooling effect can be further enhanced without impairing strength and productivity in press working.

  In addition, high temperature demagnetization of permanent magnets can be suppressed without increasing the thickness of permanent magnets or using techniques such as increasing the content of dysprosium, enabling higher efficiency and lower costs. It becomes.

  Further, by increasing the effect of suppressing the high temperature demagnetization of the permanent magnet, it becomes possible to further increase the winding current of the stator, so that the output of the motor can be increased.

  In addition, in order to obtain an output equivalent to that of a conventional electric motor, it is possible to reduce the cost by adopting a permanent magnet having a smaller coercive force or designing a thinner permanent magnet.

  Note that the configuration shown in the above embodiment is an example of the configuration of the present invention, and can be combined with another known technique, and a part thereof is omitted without departing from the gist of the present invention. Needless to say, it is possible to change the configuration.

DESCRIPTION OF SYMBOLS 1 Rotor 2 Shaft 2a Shaft insertion hole 3 Rotor core 4 End plate 5 Permanent magnet 5a Both ends of the permanent magnet in the circumferential direction 6 Magnet insertion hole 6a Both ends in the circumferential direction of the magnet insertion hole 7 Through holes 8, 8a, 8b, 8c Air gap 9 Notch 10, 10a, 10b Hole 11 Sealed compressor 12 Condenser 13 Pressure reducing device 14 Evaporator 15 Temperature sensor 16 Bypass circuit (liquid injection circuit)
DESCRIPTION OF SYMBOLS 17 Pressure reducing device 18 On-off valve 19 Sealed container 20 Compression mechanism 21 Electric motor 22 Stator 23 Refrigerant suction pipe 24 Refrigerant discharge pipe 25 Control circuit

Claims (9)

A hermetic compressor comprising: an electric motor installed in a cylindrical sealed container whose top and bottom are closed; and a compression mechanism that is installed in the sealed container together with the electric motor and driven by the electric motor,
The rotor of the electric motor is
A rotor core formed by laminating a plurality of electromagnetic steel plates each having a plurality of magnet insertion holes provided at equiangular intervals along the circumferential outer periphery;
A plurality of permanent magnets that are inserted alternately into the magnet insertion holes adjacent to each other to form magnetic poles;
An end plate for sandwiching the rotor core in the axial direction and fixing the permanent magnet in the axial direction;
With
The plurality of magnet insertion holes are formed such that gaps are generated at both ends in the circumferential direction of the magnet insertion holes when the permanent magnet is inserted,
The end plate is cut out corresponding to the peripheral position between each magnetic pole portion including the circumferential end portion of the adjacent permanent magnet,
A hermetic compressor, wherein the air gap is used as a refrigerant flow path for the refrigerant to flow therethrough.   2. The hermetic compressor according to claim 1, wherein the magnet insertion hole is formed such that a corner on an outer peripheral side of the permanent magnet is exposed to the gap.   3. The hermetic compressor according to claim 1, wherein the magnet insertion hole is formed such that a corner portion on the shaft side of the permanent magnet is in contact with an electromagnetic steel plate forming the rotor core. The magnet insertion hole, upon inserting the permanent magnets, to any one of claims 1 to 3, characterized in that voids in the surface of the shaft side of the magnet insertion holes are formed so as to further results The hermetic compressor as described. A refrigeration cycle apparatus that performs a refrigeration cycle by a compressor, a condenser, a decompression device, and an evaporator,
A hermetic compressor according to any one of claims 1 to 4 ,
When the temperature of the permanent magnet rises abnormally, a low-temperature liquid refrigerant is directly injected into the hermetic compressor by bypassing between the liquid refrigerant discharge port of the condenser and the gas suction port of the hermetic compressor. A refrigeration cycle apparatus characterized by: A temperature sensor for detecting the temperature of the gas outlet of the hermetic compressor;
A bypass circuit configured by connecting a pressure reducing device and an on-off valve in series between a liquid refrigerant discharge port of the condenser and a gas suction port of the hermetic compressor;
A control circuit for controlling the on-off valve based on a temperature detected by the temperature sensor;
The refrigeration cycle apparatus according to claim 5 , comprising: The refrigeration cycle apparatus according to claim 6 , wherein the control circuit controls the on-off valve so that a temperature detected by the temperature sensor does not exceed a predetermined temperature set in advance. The refrigeration cycle apparatus according to claim 6 , wherein the control circuit controls the on-off valve to be in an open state when a temperature detected by the temperature sensor exceeds a predetermined temperature set in advance. An air conditioner comprising the refrigeration cycle apparatus according to any one of claims 5 to 8 .

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