JP7426893B2 - Motor system and rotary compressor - Google Patents

Description

The present disclosure relates to a motor system and a rotary compressor.

A rotary compressor is known as a device used to compress refrigerant in an air conditioner. A rotary compressor includes a motor, a shaft driven by the motor, a rotary piston attached to the shaft, and a cylinder covering the rotary piston. The refrigerant is compressed by eccentric rotation of the rotary piston within the compression chamber of the cylinder.

In recent years, a type of motor called an axial gap motor has been widely used as the above-mentioned motor (for example, Patent Document 1 listed below). The axial gap motor described in Patent Document 1 includes one rotor and two stators facing the rotor from both sides in the axial direction. The rotor has a disk shape centered on the axis, and permanent magnets are arranged along the outer periphery on both sides in the thickness direction.

Japanese Patent Application Publication No. 2018-078674

Incidentally, it is known that permanent magnets such as those described above are easily demagnetized in high-temperature environments. Examples of using rare earth magnets (rare earth magnets with a large amount of heavy rare earth elements added) have also been put into practical use as magnets that are difficult to demagnetize even in high-temperature environments. However, since such rare earth magnets are generally expensive, they become a factor that increases the cost of the axial gap motor.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a motor system and a rotary compressor that are inexpensive and capable of stable operation even in a high-temperature environment.

In order to solve the above problems, a motor system according to the present disclosure includes a shaft extending along an axis, a disc-shaped rotor provided on the shaft and centered on the axis, and one side of the rotor in the axial direction. a first magnet disposed on a surface facing the other side of the rotor in the axial direction; a second magnet disposed on a surface facing the other side in the axial direction of the rotor and having characteristics different from those of the first magnet; an axial gap motor having a first stator facing from one side and having a first coil; a second stator facing the rotor from the other side in the axial direction and having a second coil; a power supply unit capable of selectively supplying power to the coil and the second coil , the second magnet has a power supply unit that can be used for protection based on a difference in the amount of heavy rare earth elements added compared to the first magnet. The magnet further includes a temperature detection section that has high magnetic force and residual magnetic flux density and detects the temperatures of the first magnet and the second magnet, and the power supply section is configured such that the detected temperature is below a predetermined threshold. In this case, power is supplied to the first coil and the second coil, and power is supplied only to the second coil when the detected temperature is higher than the threshold value .

According to the present disclosure, it is possible to provide a motor system and a rotary compressor that are inexpensive and can be operated stably even in a high-temperature environment.

FIG. 1 is a longitudinal cross-sectional view showing the configuration of a compressor according to a first embodiment of the present disclosure. FIG. 2 is an HB diagram of a first magnet and a second magnet according to the first embodiment of the present disclosure. It is a circuit diagram showing a modification of the motor system according to the first embodiment of the present disclosure. FIG. 6 is an HB diagram of a first magnet and a second magnet according to a second embodiment of the present disclosure.

<First embodiment>
(Configuration of rotary compressor)
Hereinafter, a rotary compressor 100 (compressor) according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the rotary compressor 100 according to this embodiment includes a motor system M and a compression section P. The compression section P is driven by the power generated by the motor system M, and the refrigerant is compressed.

(Motor system configuration)
The motor system M includes an axial gap motor 70, a power supply section 80, and a temperature detection section 90.

(Axial gap motor configuration)
The axial gap motor 70 has a shaft 1, a rotor 2, and a stator 3.

The shaft 1 has a shaft main body 1H and an eccentric shaft 11. The shaft body 1H has a columnar shape extending along the axis Ac. The eccentric shaft 11 has a disc shape that is eccentric in the radial direction with respect to the axis Ac. The eccentric shaft 11 is housed in a cylinder 4, which will be described later.

The rotor 2 is integrally provided at a midway position (center) of the shaft body 1H. The rotor 2 includes a rotor core 21 and permanent magnets 22 (a first magnet 22A and a second magnet 22B). The rotor core 21 has a disk shape centered on the axis Ac. Permanent magnet 22 has a ring shape extending along the periphery of rotor core 21 . Note that instead of the permanent magnets 22, it is also possible to adopt a configuration in which a plurality of magnets are arranged around the periphery of the rotor core 21 at intervals in the circumferential direction.

The permanent magnet 22 provided on one side (that is, the upper side) of the rotor core 21 in the direction of the axis Ac is a first magnet 22A. The permanent magnet 22 provided on the other side (that is, the lower side) of the rotor core 21 in the direction of the axis Ac is a second magnet 22B. There is a difference in characteristics between the first magnet 22A and the second magnet 22B as shown in FIG. Specifically, the second magnet 22B has a higher coercive force and a higher residual magnetic flux density than the first magnet 22A. Note that the horizontal axis in FIG. 2 represents coercive force, and the vertical axis represents residual magnetic flux density. Specifically, rare earth magnets including neodymium magnets are preferably used as the first magnet 22A and the second magnet 22B. The above-mentioned difference between coercive force and residual magnetic flux density is determined based on the amount of heavy rare earth element added. That is, the second magnet 22B has a larger amount of heavy rare earth elements added than the first magnet 22A.

The stator 3 is arranged to face the rotor 2 from both sides in the direction of the axis Ac, and includes an upper stator 3A (first stator) and a lower stator 3B (second stator). The upper stator 3A faces the rotor 2 from one side (upper side) in the direction of the axis Ac. The upper stator 3A includes a back yoke 31A, teeth 32A, and a coil 33A (first coil). The back yoke 31A has an annular shape centered on the axis Ac. An opening through which the shaft 1 is inserted is formed in a portion including the center of the back yoke 31A. The teeth 32A are located on the surface of the back yoke 31A facing the other side (lower side) in the direction of the axis Ac, and have a rod shape that protrudes in the direction of the axis Ac from a central position in the radial direction. A plurality of teeth 32A are arranged at equal intervals in the circumferential direction with respect to the axis Ac. The coil 33A is formed by winding a copper wire around each tooth 32A. Electric power is supplied to the coil 33A from a power supply unit 80, which will be described later.

The lower stator 3B includes a back yoke 31B, teeth 32B, and a coil 33B (second coil). The back yoke 31B has an annular shape centered on the axis Ac. An opening through which the shaft 1 is inserted is formed in a portion including the center of the back yoke 31B. The teeth 32B are located on a surface of the back yoke 31B facing one side (upper side) in the direction of the axis Ac, and have a rod shape that protrudes in the direction of the axis Ac from a central position in the radial direction. A plurality of teeth 32B are arranged at equal intervals in the circumferential direction with respect to the axis Ac. The coil 33B is formed by winding a copper wire around each tooth 32B. Electric power is supplied to the coil 33B from a power supply section 80, which will be described later. As a result, the upper stator 3A and the lower stator 3B are excited, and the shaft 1 is rotated by the electromagnetic force generated between the upper stator 3A and the lower stator 3B. In other words, the rotor 2 and stator 3 constitute a one-rotor, two-stator type axial gap motor.

The cylinder 4 is in contact with the other side (lower side) of the lower stator 3B in the axis line Ac direction. The cylinder 4 has a cylindrical shape centered on the axis Ac. Inside the cylinder 4, the above-mentioned eccentric shaft 11 and a ring-shaped rotary piston 12 fitted into the eccentric shaft 11 are housed. Further, a suction port 8 for introducing refrigerant from the outside is provided in a part of the cylinder 4 in the circumferential direction. That is, the cylinder 4 forms a compression chamber C for compressing refrigerant introduced from the outside. This compression chamber C is located on the second magnet 22B side (that is, on the lower side) of the axial gap motor 70 in the direction of the axis line Ac.

The end plate 5 (lower end plate 5B) is in contact with the other side (lower side) of the cylinder 4 in the axis line Ac direction. In other words, the lower end plate 5B and the back yoke 31B sandwich the cylinder 4 from the direction of the axis line Ac. The lower end plate 5B has a disk shape centered on the axis Ac. A bearing 6 (lower bearing 6B) is attached to a portion including the center of the lower end plate 5B.

Another end plate 5 (upper end plate 5A) is provided on one side (upper side) of the axial gap motor 70 in the axis line Ac direction. The upper end plate 5A has a disk shape centered on the axis Ac. Another bearing 6 (upper bearing 6A) is attached to a portion including the center of the upper end plate 5A. The shaft end of the shaft body 1H is supported by the upper bearing 6A and the lower bearing 6B. Further, the upper end plate 5A and the lower end plate 5B are fixed to the inner circumferential surface of the housing 7 in a tight fit state.

(Configuration of power supply section and temperature detection section)
The power supply unit 80 supplies power to the axial gap motor 70 described above. The power supply section 80 includes a first inverter 81A, a second inverter 81B, and a control section 82. The first inverter 81A is capable of supplying power to the coil 33A (first coil) of the upper stator 3A. The second inverter 81B is capable of supplying power to the coil 33B (second coil) of the lower stator 3B. The control unit 82 switches the energization state of the first inverter 81A and the second inverter 81B based on the detection result of the temperature detection unit 90. In other words, the power supply unit 80 can selectively supply power to the coil 33A and the coil 33B.

The temperature detection unit 90 is a sensor that detects the temperature of the permanent magnet 22. When the temperature detected by the temperature detection section 90 is below a predetermined threshold (that is, when the axial gap motor 70 is operated under a normal temperature environment), the control section 82 controls the first inverter 81A, and the second inverter 81B are both energized. Thereby, electromagnetic force is generated between the coil 33A and the first magnet 22A and between the coil 33B and the second magnet 22B. As a result, the axial gap motor 70 is driven under the maximum torque that it can generate.

On the other hand, when the temperature detected by the temperature detection section 90 is higher than a predetermined threshold (that is, when the axial gap motor 70 is operated in a relatively high temperature environment), the control section 82 Only the second inverter 81B is energized. Thereby, electromagnetic force is generated only between the coil 33B and the second magnet 22B. As a result, the axial gap motor 70 is continuously driven in a high temperature environment with a torque lower than the maximum torque that can be generated.

(effect)
When operating the rotary compressor 100, first, power is supplied from the power supply section 80 to the axial gap motor 70. As a result, an electromagnetic force is generated between the coils 33A, 33B and the permanent magnet 22, and the shaft 1 is rotationally driven around the axis Ac. As the shaft 1 rotates, the rotary piston 12 rotates eccentrically within the compression chamber C. As a result, the volume of the compression chamber C changes over time, and the refrigerant introduced from the outside is gradually compressed and becomes high-pressure refrigerant. The high-pressure refrigerant passes through the housing 7 and is taken out from the discharge port 7A.

By the way, it is known that the permanent magnet 22 as described above is easily demagnetized in a high temperature environment. In particular, in the compression chamber C, since the refrigerant that has been compressed to a high temperature is flowing, it can be said that the environment is such that demagnetization is likely to occur. Examples of using rare earth magnets (rare earth magnets with a large amount of heavy rare earth elements added) have also been put into practical use as magnets that are difficult to demagnetize even in such high-temperature environments. However, since rare earth magnets are generally expensive, this becomes a factor that increases the cost of the axial gap motor 70.

However, according to the above configuration, the rotor 2 is provided with the first magnet 22A and the second magnet 22B having different characteristics. By selectively supplying power to the first coil 33A and the second coil 33B, the axial gap motor 70 can be operated with a high degree of freedom according to the characteristics of the first magnet 22A and the second magnet 22B. It becomes possible to drive. In other words, by using expensive magnets that are resistant to demagnetization in only a portion of the magnets, it is possible to provide a motor system M that can be operated continuously even in a high-temperature environment while suppressing manufacturing costs.

According to the above configuration, only the second magnet 22B is a magnet with high coercive force and high residual magnetic flux density, and the first magnet 22A is a magnet with characteristics inferior to that of the second magnet 22B. That is, compared to a configuration in which both the first magnet 22A and the second magnet 22B are magnets with high characteristics, the manufacturing cost of the device can be kept low.

According to the above configuration, the operation of the power supply section 80 is switched based on the temperatures of the first magnet 22A and the second magnet 22B. If the temperature of these magnets is higher than the threshold, power is supplied only to the second coil 33B. That is, in this case, the axial gap motor 70 can continue to be driven under a lower torque than under a normal temperature environment. Thus, for example, if it is necessary to continue operation in a high-temperature environment while sacrificing torque, the above-mentioned configuration can satisfy the requirement.

In the above configuration, the second magnet 22B of the axial gap motor 70 is located on the side of the compression chamber C that tends to become high temperature. In other words, the second magnet 22B, which has a property of being relatively difficult to demagnetize even in a high temperature environment, is arranged on the high temperature side. This makes it possible to stably obtain torque even in a high-temperature environment, making it possible to operate the compressor more stably.

The first embodiment of the present disclosure has been described above. Note that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, in the first embodiment, the power supply unit 80 has two inverters (the first inverter 81A and the second inverter 81B), and each inverter individually excites the coils 33A and 33B. However, it is also possible to adopt a configuration as shown in FIG. 3 as a modification. The power supply unit 80' shown in the figure has only one inverter 81' and three switches S1, S2, and S3. Each phase of the coil 33A (U1 phase, V1 phase, W1 phase) and each phase of the coil 33B (U2 phase, V2 phase, W2 phase) are connected in parallel to the inverter 81'. A switch S1 is provided between the U1 phase and the U2 phase, and a switch S2 is provided between the V1 phase and the V2 phase. A switch S3 is provided between the W1 phase and the W2 phase. When the temperature detected by the temperature detection section 90 described above becomes equal to or higher than the threshold value, the switches S1 to S3 are cut off (ie, turned off), so that only the coil 33B is excited. In this way, by only using one inverter 81' and three switches S1 to S3, it is possible to realize the same functions as in the first embodiment at a lower cost.

<Second embodiment>
Next, a second embodiment of the present disclosure will be described with reference to FIG. 4. Note that the same components as in the first embodiment are given the same reference numerals, and detailed explanations will be omitted. In this embodiment, the characteristics of the first magnet 22A and the second magnet 22B are different from those in the first embodiment. As shown in FIG. 4, the first magnet 22A has a lower coercive force and a higher residual magnetic flux density than the first magnet 22A. As an example of a combination exhibiting such characteristics, a neodymium magnet is used for the first magnet 22A, and a samarium cobalt magnet is used for the second magnet 22B.

According to the above configuration, only the second magnet 22B has a low coercive force and a high residual magnetic flux density, and the first magnet 22A has a characteristic inferior to that of the second magnet 22B. That is, compared to a configuration in which both the first magnet 22A and the second magnet 22B are magnets with high characteristics, the manufacturing cost of the device can be kept low.

Further, similarly to the first embodiment, the operation of the power supply section 80 is switched based on the temperatures of the first magnet 22A and the second magnet 22B. If the temperature of these magnets is higher than the threshold, power is supplied only to the first coil 33A. Thereby, electromagnetic force is generated only between the first magnet 22A, which has a relatively high residual magnetic flux density, and the first coil 33A. In this case, the axial gap motor 70 can continue to be driven under a lower torque than under a normal temperature environment. Thus, for example, if it is necessary to continue operation in a high-temperature environment while sacrificing torque, the above-mentioned configuration can satisfy the requirement.

The first embodiment of the present disclosure has been described above. Note that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, it is also possible to apply the configuration of the power supply section 80' described as a modification of the first embodiment.

Furthermore, as a modification common to each of the embodiments described above, it is also possible to make the coercive force and residual magnetic flux density different by making the dimensions (thickness) of the first magnet 22A and the second magnet 22B different. For example, when the torque required in a high-temperature environment is determined in advance, the dimensions of the first magnet 22A or the second magnet 22B are determined so as to satisfy the magnetic force characteristics that can achieve the torque value. Is possible. This further reduces the amount of magnets required and reduces manufacturing costs. Moreover, it is also possible to provide the above-mentioned difference in torque by varying not only the dimensions of the magnets but also the dimensions of the coils 33A and 33B (dimensions in the direction of the axis line Ac). In other words, it is possible to reduce the length of the coil 33A or 33B to the minimum length so as to satisfy the torque required in a high temperature environment. This makes it possible to further reduce the size of the axial gap motor 70.

<Additional notes>
The motor system M and the rotary compressor 100 (compressor) described in each embodiment are understood as follows, for example.

(1) A motor system M according to a first aspect includes a shaft 1 extending along an axis Ac, a disc-shaped rotor 2 provided on the shaft 1 and centered on the axis Ac, and a rotor 2 of the rotor 2. A first magnet 22A disposed on a surface facing one side in the axis Ac direction, and a second magnet 22B disposed on a surface facing the other side in the axis Ac direction of the rotor 2 and having characteristics different from those of the first magnet 22A. a first stator 3A that faces the rotor 2 from one side in the direction of the axis Ac and has a first coil 33A; and a second stator 33B that faces the rotor 2 from the other side in the direction of the axis Ac. A second stator 3B having a second stator 3B, an axial gap motor 70 having a second stator 3B, and a power supply section 80 capable of selectively supplying power to the first coil 33A and the second coil 33B.

According to the above configuration, by selectively supplying power to the first coil 33A and the second coil 33B, a high degree of freedom can be achieved according to the characteristics of the first magnet 22A and the second magnet 22B. This makes it possible to operate the axial gap motor 70.

(2) In the motor system M according to the second aspect, the second magnet 22B has a higher coercive force and a higher residual magnetic flux density than the first magnet 22A.

According to the above configuration, only the second magnet 22B is a magnet with high coercive force and high residual magnetic flux density, and the first magnet 22A is a magnet with characteristics inferior to that of the second magnet 22B. That is, compared to a configuration in which both the first magnet 22A and the second magnet 22B are magnets with high characteristics, the manufacturing cost of the device can be kept low.

(3) The motor system M according to the third aspect further includes a temperature detection unit 90 that detects the temperatures of the first magnet 22A and the second magnet 22B, and the power supply unit 80 When the temperature is below a predetermined threshold, power is supplied to the first coil 33A and the second coil 33B, and when the detected temperature is higher than the threshold, the second coil 33B is supplied with power. Provides power only to

It is known that permanent magnets experience demagnetization in high-temperature environments. Examples of using rare earth magnets (rare earth magnets containing a large amount of heavy rare earth elements) have also been put into practical use as magnets that are difficult to demagnetize even in high-temperature environments. However, such rare earth magnets are generally expensive, which causes an increase in manufacturing costs. However, according to the above configuration, the operation of the power supply section 80 is switched based on the temperatures of the first magnet 22A and the second magnet 22B. If the temperature of these magnets is higher than the threshold, power is supplied only to the second coil 33B. That is, in this case, the axial gap motor 70 can continue to be driven under a lower torque than under a normal temperature environment. Thus, for example, if it is necessary to continue operation in a high-temperature environment while sacrificing torque, the above configuration can satisfy the requirement.

(4) In the motor system M according to the fourth aspect, the second magnet 22B has a lower coercive force and a higher residual magnetic flux density than the first magnet 22A.

According to the above configuration, only the second magnet 22B has a low coercive force and a high residual magnetic flux density, and the first magnet 22A has a characteristic inferior to that of the second magnet 22B. That is, compared to a configuration in which both the first magnet 22A and the second magnet 22B are magnets with high characteristics, the manufacturing cost of the device can be kept low.

(5) The motor system M according to the fifth aspect further includes a temperature detection unit that detects the temperatures of the first magnet and the second magnet, and the power supply unit is configured such that the detected temperature is determined in advance. If the detected temperature is below the threshold value, power is supplied to the first coil and the second coil, and if the detected temperature is higher than the threshold value, power is supplied only to the first coil.

According to the above configuration, the operation of the power supply section 80 is switched based on the temperatures of the first magnet 22A and the second magnet 22B. If the temperature of these magnets is higher than the threshold, power is supplied only to the first coil 33A. Thereby, electromagnetic force is generated only between the first magnet 22A, which has a relatively high residual magnetic flux density, and the first coil 33A. In this case, the axial gap motor 70 can continue to be driven under a lower torque than under a normal temperature environment. Thus, for example, if it is necessary to continue operation in a high-temperature environment while sacrificing torque, the above-mentioned configuration can satisfy the requirement.

(6) The compressor according to the sixth aspect includes a motor system M, a rotary piston 12 that rotates eccentrically together with the shaft 1, and a cylinder 4 that forms a compression chamber C in which the rotary piston 12 is accommodated. .

According to the above configuration, a compressor that can be stably operated in a high temperature environment can be provided at a low cost.

(7) In the compressor according to the seventh aspect, the axial gap motor 70 is arranged such that the second magnet 22B is located on the compression chamber C side in the direction of the axis Ac.

In the compression chamber C, compressed refrigerant that has become high temperature flows. In the above configuration, the second magnet 22B of the axial gap motor 70 is located on the side of the compression chamber C that tends to become high temperature. In other words, the second magnet 22B, which has a property of being relatively difficult to demagnetize even in a high temperature environment, is arranged on the high temperature side. This makes it possible to stably obtain torque even in a high-temperature environment, making it possible to operate the compressor more stably.

100 Rotary compressor 1 Shaft 1H Shaft body 11 Eccentric shaft 12 Rotary piston 2 Rotor 21 Rotor core 22 Permanent magnet 22A First magnet 22B Second magnet 3 Stator 3A Upper stator 3B Lower stator 31A, 31B Back yoke 32A, 32B Teeth 33A, 33B Coil 4 Cylinder 5 End plate 5A Upper end plate 5B Lower end plate 6 Bearing 6A Upper bearing 6B Lower bearing 7 Housing 7A Discharge port 8 Suction port 70 Axial gap motor 80, 80' Power supply section 81A First inverter 81B Second inverter 81 ' Inverter 82 Control section 90 Temperature detection section Ac Axis C Compression chamber M Motor system P Compression section

Claims (4)

a shaft extending along the axis;
a disc-shaped rotor provided on the shaft and centered on the axis;
a first magnet disposed on a surface facing one side in the axial direction of the rotor;
a second magnet that is disposed on a surface facing the other side in the axial direction of the rotor and has characteristics different from those of the first magnet;
a first stator that faces the rotor from one side in the axial direction and has a first coil;
a second stator that faces the rotor from the other side in the axial direction and has a second coil;
an axial gap motor having
a power supply unit capable of selectively supplying power to the first coil and the second coil;
Equipped with
The second magnet has a higher coercive force and residual magnetic flux density than the first magnet based on the difference in the amount of heavy rare earth elements added,
further comprising a temperature detection unit that detects the temperatures of the first magnet and the second magnet,
The power supply unit supplies power to the first coil and the second coil when the detected temperature is below a predetermined threshold, and the detected temperature is higher than the threshold. In this case, the motor system supplies power only to the second coil . a shaft extending along the axis;
a disc-shaped rotor provided on the shaft and centered on the axis;
a first magnet disposed on a surface facing one side in the axial direction of the rotor;
a second magnet disposed on a surface facing the other side in the axial direction of the rotor and having characteristics different from those of the first magnet;
a first stator that faces the rotor from one side in the axial direction and has a first coil;
a second stator that faces the rotor from the other side in the axial direction and has a second coil;
an axial gap motor having
a power supply unit capable of selectively supplying power to the first coil and the second coil;
Equipped with
The second magnet has a lower coercive force and a higher residual magnetic flux density than the first magnet, based on the difference in the amount of heavy rare earth elements added,
further comprising a temperature detection unit that detects the temperatures of the first magnet and the second magnet,
The power supply unit supplies power to the first coil and the second coil when the detected temperature is below a predetermined threshold, and the detected temperature is higher than the threshold. In this case, the motor system supplies power only to the first coil . A motor system according to claim 1 or 2 ,
a rotary piston that rotates eccentrically together with the shaft;
a cylinder forming a compression chamber in which the rotary piston is housed;
A rotary compressor equipped with. The rotary compressor according to claim 3 , wherein the axial gap motor is arranged such that the second magnet is located on the compression chamber side in the axial direction.

Images