Rotary electric machine, compressor, and refrigeration device

Abstract

To increase the output torque of a rotary electric machine.SOLUTION: A rotary electric machine (20) includes a rotor (31) having a rotor core (32) and a magnet (33) and configured to rotate about a rotation axis (O), and a stator (21) disposed radially outside the rotor (31) and having a stator core (22). The rotor (31) includes a first rotor portion (31a portion) that faces the stator core (22) in the radial direction and generates reluctance torque, and a second rotor portion (31a portion) that does not face the stator core (22) in the radial direction and is disposed adjacent to the first rotor portion (31b portion) in the axial direction. The volume per unit length in the axial direction of the magnet (33) included in the second rotor portion (31b portion) is larger than the volume per unit length in the axial direction of the magnet (33) included in the first rotor portion (31a portion).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to rotating electrical machines, compressors and refrigeration systems. [Background technology]

[0002] Patent Document 1 discloses a synchronous motor in which the axial length of a rotor, in which magnets are arranged in a radial direction, is longer than the axial length of a stator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-319583 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the synchronous motor of Patent Document 1, the reluctance torque of the rotor portion that does not face the stator in the radial direction is small, so the output torque of the synchronous motor relative to the axial length of the rotor decreases.

[0005] An object of the present disclosure is to increase the output torque of a rotating electrical machine. [Means for solving the problem]

[0006] A first aspect of the present disclosure is a rotating electric machine (20) including: a rotor (31) having a rotor core (32) and magnets (33) and rotating about a rotation axis (O); and a stator (21) disposed radially outward of the rotor (31) and having a stator core (22). The rotor (31) includes a first rotor portion (31a) radially facing the stator core (22) and generating reluctance torque, and a second rotor portion (31b) not radially facing the stator core (22) and disposed adjacent to the first rotor portion (31a) in the axial direction. The volume per unit length in the axial direction of the magnets (33) included in the second rotor portion (31b) is larger than the volume per unit length in the axial direction of the magnets (33) included in the first rotor portion (31a).

[0007] In the first mode, by increasing the volume per unit axial length of the magnets (33) included in the second rotor portion (31b) that does not radially face the stator core (22), the increase in magnet torque can be made greater than the decrease in reluctance torque, thereby increasing the output torque of the rotating electric machine (20).

[0008] A second aspect of the present disclosure is the first aspect, wherein the rotor core (32) of the first rotor portion (31 a) has first holes (34 a) in which the magnets (33) are arranged and a first core region (36 a) located radially outward from the first holes (34 a), and the rotor core (32) of the second rotor portion (31 b) has second holes (37 a) in which the magnets (33) are arranged and a second core region (39 a) located radially outward from the second holes (37 a). The first core region (36 a) and the second core region (39 a) form a magnetic path from the magnets (33) arranged in the second holes (37 a) to the stator core (22).

[0009] In the second mode, the magnet torque can be increased by the magnet (33) arranged in the second hole (37a) of the second rotor part (31b) that does not radially face the stator core (22).

[0010] A third aspect of the present disclosure is related to the first or second aspect, wherein the rotor core (32) includes a first rotor core portion (32a) and a second rotor core portion (32b). At least a portion of the first rotor core portion (32a) is disposed in the first rotor portion (31a), and at least a portion of the second rotor core portion (32b) is disposed in the second rotor portion (31b). The first rotor core portion (32a) has substantially the same shape in cross section perpendicular to the axial direction, and includes third hole portions (35a, 35b) in which the magnets (33) are disposed. The second rotor core portion (32b) has substantially the same shape in cross section perpendicular to the axial direction, and includes fourth hole portions (38a) in which the magnets (33) are disposed. The volume per unit axial length of the magnet (33) arranged in the fourth hole portion (38a) of the second rotor core portion (32b) is larger than the volume per unit axial length of the magnet (33) arranged in the third hole portion (35a, 35b) of the first rotor core portion (32a).

[0011] In the third aspect, at least a part of the second rotor core (32b) having a large volume per unit length in the axial direction of the magnet (33) is disposed in the second rotor part (31b), thereby increasing the volume per unit length in the axial direction of the magnet (33) included in the second rotor part (31b).

[0012] A fourth aspect of the present disclosure is the third aspect, wherein the number of the third holes (35a, 35b) is greater than the number of the fourth holes (38a).

[0013] In the fourth mode, the first rotor core portion (32a) is likely to generate both reluctance torque and magnet torque, and the second rotor core portion (32b) is likely to generate mainly magnet torque.

[0014] A fifth aspect of the present disclosure is the third or fourth aspect, wherein two or more of the third holes (35a, 35b) and one of the fourth holes (38a) are adjacent to each other in the axial direction.

[0015] In the fifth aspect, it is possible to prevent the magnetic flux from flowing through the first rotor core portion (32a) or the second rotor core portion (32b) and becoming leakage magnetic flux.

[0016] A sixth aspect of the present disclosure is the fifth aspect, wherein the sum of the radial lengths of two or more third hole portions (35a, 35b) axially adjacent to the fourth hole portion (38a) is greater than the radial distance between the stator core (22) and the rotor core (32).

[0017] In the sixth aspect, the magnetic resistance of the magnetic path passing only through the rotor core (32) is greater than the magnetic resistance of the magnetic path passing through the rotor core (32) and the stator core (22), thereby suppressing leakage magnetic flux between the first rotor core portion (32a) and the second rotor core portion (32b).

[0018] A seventh aspect of the present disclosure is any one of the third to sixth aspects, wherein the first rotor core portion (32a) has a shape that is convex from the radial outside toward the third hole portion (35a) in a cross-sectional shape perpendicular to the axial direction, and the second rotor core portion (32b) has a shape that is convex from the radial outside toward the fourth hole portion (38a) in a cross-sectional shape perpendicular to the axial direction.

[0019] In the seventh aspect, a suitable core region is secured between the outer diameter end of the magnet (33) and the outer periphery of the rotor core (32). Therefore, the magnetic flux of the magnet flows in the axial direction through the core region, thereby increasing the magnet torque.

[0020] An eighth aspect of the present disclosure is any one of the third to seventh aspects, wherein the magnet (33) placed in the fourth hole (38a) is a ferrite magnet.

[0021] In the eighth aspect, magnetic saturation is less likely to occur in the core region where magnetic flux flows in the axial direction, compared to when a magnet with strong magnetic force, such as a neodymium magnet, is disposed.

[0022] A ninth aspect of the present disclosure is any one of the third to eighth aspects, wherein an axial end of the first rotor core portion (32a) does not face the stator core (22) in the radial direction.

[0023] In the ninth aspect, even at an end of the first rotor core portion (32a) that does not face the stator core (32) in the radial direction, a corresponding reluctance torque is generated as long as the end is close to the stator core (32). Therefore, the output torque can be made larger than in a configuration in which the entire first rotor core portion (32a) faces the stator core (32) in the radial direction.

[0024] A tenth aspect of the present disclosure is a compressor including the rotating electric machine (20) according to any one of the first to ninth aspects.

[0025] In the tenth aspect, the power consumption of the compressor can be reduced.

[0026] An eleventh aspect of the present disclosure is a refrigeration system including the rotating electric machine (20) according to any one of the first to ninth aspects.

[0027] In the eleventh aspect, the power consumption of the refrigeration device can be reduced. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a schematic diagram showing an outline of the vertical cross-sectional configuration of the motor of the first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing an outline of the cross-sectional configuration of the stator in the motor of the first embodiment. [Figure 3] FIG. 3 is a schematic diagram showing an outline of a cross-sectional configuration of a first rotor core portion in the motor of the first embodiment. [Figure 4] FIG. 4 is a schematic diagram illustrating an outline of a cross-sectional configuration of a second rotor core portion in the motor of the first embodiment. [Figure 5] FIG. 5 is a schematic diagram showing the flow of magnetic flux from a magnet in a vertical cross section of a main part of the motor of the first embodiment. [Figure 6] 6(a) to 6(c) are schematic diagrams showing variations of the longitudinal cross-sectional configuration of the main part of the motor of the first embodiment. [Figure 7] FIG. 7 is a schematic diagram showing an outline of the longitudinal cross-sectional configuration when end plates are provided at the axial ends of the rotor in the motor of the first embodiment. [Figure 8] 8(a) to 8(d) are schematic diagrams showing variations in the longitudinal cross-sectional configuration of the main part of a motor according to a first modification of the first embodiment. [Figure 9] FIG. 9 is a schematic diagram showing a vertical cross-sectional configuration of a main part of a motor according to a second modification of the first embodiment. [Figure 10] FIG. 10 is a schematic diagram showing an outline of a vertical cross-sectional configuration of a motor according to a third modification of the first embodiment. [Figure 11] 11(a) and 11(b) are schematic diagrams showing an outline of the cross-sectional configuration of the first rotor core portion and the second rotor core portion in a motor according to Modification 4 of Embodiment 1. FIG. [Figure 12] 12(a) to 12(d) are schematic diagrams showing variations in the cross-sectional configuration of the second rotor core portion in a motor according to Modification 4 of Embodiment 1. In FIG. [Figure 13] 13(a) and 13(b) are schematic diagrams showing an outline of the cross-sectional configuration of the second rotor core portion and the longitudinal-sectional configuration of the main portion in the motor of the fifth modified example. [Figure 14] FIG. 14 is a vertical cross-sectional view showing an example of the configuration of the compressor of the second embodiment. [Figure 15] FIG. 15 is a piping diagram showing an example of the configuration of a refrigeration device according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or its uses. In addition, the same reference numerals in the drawings represent the same components, but dimensions in the drawings, such as length, width, thickness, and depth, have been appropriately changed from the actual scale for clarity and simplification of the drawings, and may not correspond to the actual relative dimensions.

[0030] (Embodiment 1) <Motor> As shown in FIGS. 1 and 2, the motor (20) of the first embodiment includes a stator (21) and a rotor (31). The motor (20) is an example of a rotating electric machine (20). The motor (20) is configured as an inner rotor type. The stator (21) includes a stator core (22) and a plurality of coils (23). The stator core (22) is disposed radially outward of the rotor (31). The rotor (31) is configured to be rotatable together with the drive shaft (40). The rotor (31) rotates around the axis of the drive shaft (40) (hereinafter referred to as the rotation axis (O)). The rotor (31) includes a rotor core (32) and a plurality of magnets (33).

[0031] In this disclosure, the direction in which the rotation axis (O) extends is referred to as the "axial direction," the direction perpendicular to the "axial direction" is referred to as the "radial direction," and the direction around the rotation axis (O) is referred to as the "circumferential direction." Also, a cross section along the "axial direction" is referred to as a "longitudinal cross section," and a cross section perpendicular to the "axial direction" is referred to as a "transverse cross section."

[0032] The stator core 22 is formed by stacking a plurality of electromagnetic steel plates in the axial direction. The stator core 22 has an annular back yoke 24 and a plurality of teeth 25. The plurality of teeth 25 extend radially inward from the inner circumferential surface of the back yoke 24. The plurality of coils 23 are wound around the plurality of teeth 25.

[0033] The rotor core 32 is formed by stacking a plurality of electromagnetic steel plates in the axial direction. The plurality of magnets 33 are disposed inside the rotor core 32. The plurality of magnets 33 are permanent magnets such as ferrite magnets. The plurality of magnets 33 are arranged in the circumferential direction of the rotor core 32 and extend through the rotor core 32 in the axial direction.

[0034] The configuration of the motor (20) shown in Figures 1 and 2 is an example, and the number of poles of the motor (20), the shape of the stator core (22), the number of teeth (25) and magnets (33), the winding method of the coil (23), etc. are not particularly limited.

[0035] <Rotor> As shown in FIG. 1 , the rotor (31) has a first rotor portion (31a) and a second rotor portion (31b). The first rotor portion (31a) faces the stator core (22) in the radial direction and is configured to generate reluctance torque. The second rotor portion (31b) does not face the stator core (22) in the radial direction but is arranged adjacent to the first rotor portion (31a) in the axial direction. The axial length of the rotor (31) is longer than the axial length of the stator core (22). Both axial end regions of the rotor (31) do not face the stator core (22) in the radial direction, and a pair of second rotor portions (31b) are arranged in these end regions. The first rotor portion (31a) is sandwiched between the pair of second rotor portions (31b) in the axial direction.

[0036] A feature of the rotor 31 is that the volume per unit axial length of the magnet 33 included in the second rotor portion 31b is larger than the volume per unit axial length of the magnet 33 included in the first rotor portion 31a. The "volume per unit axial length" of the magnet 33 included in each rotor portion 31a, 31b is calculated by calculating the volume of the magnet 33 included in each rotor portion 31a, 31b and dividing the obtained volume by the axial length of each rotor portion 31a, 31b. The volume of the magnet 33 may be measured by actually removing the magnet 33 from each rotor portion 31a, 31b and using X-ray computed tomography (CT) or the like. Alternatively, without removing the magnets 33 from the rotor portions 31 a, 31 b, the internal structure of each rotor portion 31 a, 31 b may be photographed using an X-ray CT or the like, and the shape of the magnets 33 may be extracted from the photographed data to calculate the volume of the magnets 33. Alternatively, if the cross-sectional shape of the magnets 33 is the same in the axial direction, the area of ​​the axial end face of the magnets 33 may be calculated, and the area may be multiplied by the axial length of the magnets 33 to calculate the volume of the magnets 33.

[0037] As shown in FIG. 1, the rotor core (32) includes a first rotor core portion (32a) in which a first magnet (33a) is embedded and a second rotor core portion (32b) in which a second magnet (33b) is embedded. S: That is, the magnet (33) is composed of the first magnet (33a) and the second magnet (33b). At least a portion of the first rotor core portion (32a) is disposed in the first rotor portion (31a), and the cross-sectional shape of the first rotor core portion (32a) is substantially uniform in the axial direction. At least a portion of the second rotor core portion (32b) is disposed in the second rotor portion (31b), and the cross-sectional shape of the second rotor core portion (32b) is substantially uniform in the axial direction. The cross-sectional shape of the first rotor core portion (32a) (i.e., the cross-sectional shape of the first magnet (33a)) is different from the cross-sectional shape of the second rotor core portion (32b) (i.e., the cross-sectional shape of the second magnet (33b)). In this example, the entire first rotor core portion (32a) is disposed in the first rotor portion (31a), and the entire second rotor core portion (32b) is disposed in the second rotor portion (31b). In other words, the axial length of the first rotor core portion (32a) is the same as the axial length of the stator core (22), and the positions of the axial ends of the first rotor core portion (32a) are the same as the positions of the axial ends of the stator core (22). In addition, instead of the configuration of this example, as in Variation Example 3 described below, the rest of the first rotor core portion (32a) except for both axial ends thereof may be arranged in the first rotor portion (31a), and both axial ends of the first rotor core portion (32a) and the entire second rotor core portion (32b) may be arranged in the second rotor portion (31b).

[0038] A feature of the rotor core (32) is that the volume per unit axial length of the second magnet (33b) embedded in the second rotor core portion (32b) is larger than the volume per unit axial length of the first magnet (33a) embedded in the first rotor core portion (32a). The "volume per unit axial length" of each magnet (33a, 33b) is calculated by calculating the volume of each magnet (33a, 33b) and dividing the obtained volume by the axial length of each rotor core portion (32a, 32b). The volume of the magnets (33a, 33b) may be measured by X-ray CT or the like after actually removing each magnet (33a, 33b) from each rotor core portion (32a, 32b). Alternatively, if the cross-sectional shape of each magnet (33a, 33b) is the same in the axial direction, the area of ​​the axial end face of each magnet (33a, 33b) may be calculated, and the volume of each magnet (33a, 33b) may be calculated by multiplying this area by the axial length of each magnet (33a, 33b).

[0039] <Detailed rotor configuration> As shown in Figures 3 and 4, the rotor core (32) of the first rotor section (31a) has first hole portions (34a, 34b) in which the magnets (33) are arranged, and the rotor core (32) of the second rotor section (31b) has second hole portions (37a) in which the magnets (33) are arranged.

[0040] In this example, the rotor core (32) of the first rotor portion (31a) is aligned with the first rotor core portion (32a), and the rotor core (32) of the second rotor portion (31b) is aligned with the second rotor core portion (32b). Here, the first rotor core portion (32a) has third holes (35a, 35b) in which the first magnets (33a) are embedded, and the second rotor core portion (32b) has fourth holes (38a) in which the second magnets (33b) are embedded. In this example, the first holes (34a, 34b) and the third holes (35a, 35b) are aligned, and the second hole (37a) and the fourth hole (38a) are aligned.

[0041] A through hole (30) into which the drive shaft (40) is axially inserted is provided at the radial center of the first rotor core portion (32a) (first rotor portion (31a)) and the second rotor core portion (32b) (second rotor portion (31b)).

[0042] The third hole portions (35a, 35b) (first hole portions (34a, 34b)) are formed so as to penetrate the first rotor core portion (32a) in the axial direction, and the fourth hole portion (38a) (second hole portion (37a)) is formed so as to penetrate the second rotor core portion (32b) in the axial direction.

[0043] Although the rotor (31) has four poles in the example shown in FIGS. 3 and 4, the number of poles of the rotor (31) is not particularly limited.

[0044] In the first rotor core portion (32a) shown in FIG. 3, two third holes (35a, 35b) are arranged radially adjacent to one magnetic pole. The third holes (35a, 35b) include an outer hole (35a) and an inner hole (35b) arranged radially inward of the outer hole (35a). The outer hole (35a) and the inner hole (35b) each have an arc shape that protrudes radially inward as viewed in the axial direction. Ends of the outer hole (35a) and the inner hole (35b) are located near the outer periphery of the first rotor core portion (32a) as viewed in the axial direction. First magnets (33a) that are magnetically aligned in series are fitted into the outer hole (35a) and the inner hole (35b) of one magnetic pole. The outer holes (35a) and inner holes (35b) of the four magnetic poles are arranged at equal intervals in the circumferential direction so as to surround the through-hole (30).

[0045] The rotor core (32) (in this example, the first rotor core portion (32a)) of the first rotor portion (31a) has a first outer core region (36a) located radially outward from the outer hole portion (35a) (the radially outer first hole portion (34a)), a first intermediate core region (36b) located between the outer hole portion (35a) and the inner hole portion (35b) (the radially inner first hole portion (34b)), and a first inner core region (36c) located radially inward from the inner hole portion (35b).

[0046] In the second rotor core portion (32b) shown in FIG. 4, one fourth hole portion (38a) is arranged for one magnetic pole. The fourth hole portion (38a) has an arc shape that is convex radially inward when viewed in the axial direction. An end of the fourth hole portion (38a) is located near the outer periphery of the second rotor core portion (32b) when viewed in the axial direction. The second magnet (33b) is fitted into the fourth hole portion (38a). The fourth holes (38a) of the four magnetic poles are arranged at equal intervals in the circumferential direction so as to surround the through hole (30).

[0047] The rotor core (32) of the second rotor portion (31b) (in this example, the second rotor core portion (32b)) has a second outer core region (39a) located radially outward from the fourth hole portion (38a) (the second hole portion (37a)), and a second inner core region (39b) located radially inward from the fourth hole portion (38a).

[0048] In the present example shown in Figures 3 and 4, two third hole portions (35a, 35b) and one fourth hole portion (38a) are arranged for each magnetic pole, but this is not limited to this, and the number of third hole portions (35a, 35b) arranged for each magnetic pole may be two or more, and the number of fourth hole portions (38a) arranged may be fewer than the number of third hole portions (35a, 35b) arranged.

[0049] Fig. 5 shows the flow of magnetic flux from a magnet in a vertical cross section near the boundary (hereinafter referred to as the main portion) between the first rotor portion (31a) (first rotor core portion (32a)) and the second rotor portion (31b) (second rotor core portion (32b)) in the motor (20) of embodiment 1. In Fig. 5, the same elements as those in Figs. 3 and 4 are denoted by the same reference numerals.

[0050] 5, the first core region (first outer core region) (36a) of the first rotor portion (31a) and the second core region (second outer core region) (39a) of the second rotor portion (31b) form a magnetic path from the magnet (33) (second magnet (33b)) arranged in the second hole portion (37a) (fourth hole portion (38a)) to the stator core (22), thereby increasing the magnet torque.

[0051] The two third holes (35a, 35b) (first holes (34a, 34b)) and one fourth hole (38a) (second hole (37a)) are adjacent to each other in the axial direction. In this example, in the longitudinal cross section, the entire third hole (35a, 35b) is adjacent to the fourth hole (38a) in the axial direction, but this is not limited thereto, and at least a part of each third hole (35a, 35b) may be adjacent to the fourth hole (38a) in the axial direction.

[0052] On the other hand, the magnets (33) (first magnets (33a)) embedded in each of the third holes (35a, 35b) are not adjacent to the second rotor core portion (32b) (the second outer core region (39a) and the second inner core region (39b)) in the axial direction. In this example, in the longitudinal cross section, the entire first magnets (33a) embedded in each of the third holes (35a, 35b) are not adjacent to the second rotor core portion (32b) in the axial direction. However, this is not limited thereto, and at least a part of the first magnets (33a) may be adjacent to the second outer core region (39a) or the second inner core region (39b) in the axial direction.

[0053] As in this example, when the third hole portions (35a, 35b) of the first rotor core portion (32a) and the fourth hole portion (38a) of the second rotor core portion (32b) are adjacent to each other in the axial direction, in other words, when the third hole portions (35a, 35b) and the fourth hole portion (38a) overlap when viewed from the axial direction, advantages are obtained in terms of manufacturing and motor performance, as described below.

[0054] The advantage in terms of manufacturing is a reduction in the cost of dies used in the press working. In manufacturing the rotor core 32 of this example, the first rotor core 32a is first punched out from an electromagnetic steel plate (sheet), and then the first intermediate core region 36b (see FIG. 3) is punched out and removed from the first rotor core 32a to manufacture the second rotor core 32b. The die for manufacturing the second rotor core 32b from the first rotor core 32a is simpler than the die for punching the second rotor core 32b directly out of an electromagnetic steel plate (sheet), and therefore the manufacturing cost (die cost) can be reduced.

[0055] The benefit in terms of motor performance is improved motor efficiency due to the suppression of leakage magnetic flux between the first rotor core portion (32a) and the second rotor core portion (32b). For example, as shown in FIG. 6(c), if the core (first rotor core portion (32a)) is arranged so as to be adjacent to the magnet (second magnet (33b)) in the axial direction, the magnetic flux of the magnet flows through the core, resulting in leakage magnetic flux. The leakage magnetic flux does not contribute to torque and therefore reduces motor efficiency. In contrast, in the present example shown in FIG. 5, the core (first rotor core portion (32a)) adjacent to the magnet (second magnet (33b)) has a gap (third hole portion (35a, 35b)). Therefore, the gap acts as a so-called flux barrier, suppressing leakage magnetic flux.

[0056] One conventional technique for suppressing leakage flux through a core adjacent to a magnet is to place two cores in the axial direction with a non-magnetic material between them. However, this conventional technique causes problems: the non-magnetic material reduces the motor's energy density, obstructing the magnetic flux flowing in the axial direction and reducing the magnet torque. In contrast, the configuration of this example shown in Figure 5 does not have a non-magnetic material between the magnet and core, so the problems of the conventional technique do not occur and motor performance can be improved compared to the conventional technique.

[0057] To suppress leakage magnetic flux between the cores, it is desirable that the total radial length of two or more (two in this example) third holes (35a, 35b) axially adjacent to the fourth hole (38a) be greater than the radial distance between the stator core (22) and the rotor core (32). The reason for this is explained below. In the configuration of this example shown in FIG. 5, the magnetic resistance of the magnetic path (the magnetic path of leakage magnetic flux shown in FIG. 6(c)) that short-circuits one magnet (the second magnet (33b)) corresponds to the total radial length of the third holes (35a, 35b). On the other hand, the magnetic resistance of the original magnetic path through which the magnetic flux passes on the stator side (specifically, the path of "magnet A of one magnetic pole → rotor core → stator core (teeth → back yoke → other teeth) → rotor core → magnet B of another magnetic pole → magnet A") corresponds to twice the radial distance (gap) between the stator core and the rotor core. However, since there are two magnets in this magnetic path, the magnetic reluctance of each magnet corresponds to the "gap." Therefore, in the configuration of this example shown in FIG. 5, if the "total radial length of the fourth hole portion (38a) and two or more third hole portions (35a, 35b) axially adjacent to it" is made larger than the "radial distance between the stator core (22) and the rotor core (32)," leakage magnetic flux between the first rotor core portion (32a) and the second rotor core portion (32b) can be suppressed. Note that in the magnetic reluctance relationship described above, the "magnetic reluctance of the core" is ignored because it is much smaller than the "magnetic reluctance of the magnet" and the "magnetic reluctance of the gap."

[0058] 5, in the longitudinal cross section, the entire third hole portions (35a, 35b) of the first rotor core portion (32a) are configured to be adjacent to the fourth hole portion (38a) of the second rotor core portion (32b) in the axial direction. In other words, the first outer core region (36a) of the first rotor portion (31a) and the second outer core region (39a) of the second rotor portion (31b) are configured to be adjacent to each other in the axial direction, and the first inner core region (36c) of the first rotor portion (31a) and the second inner core region (39b) of the second rotor portion (31b) are configured to be adjacent to each other in the axial direction. Alternatively, as shown in Fig. 6(a), for example, in a configuration in which the first intermediate core region (36b) of the first rotor portion (31a) is not adjacent to the second outer core region (39a) and the second inner core region (39b) of the second rotor portion (31b) in the axial direction, the third hole portions (35a, 35b) and the fourth hole portion (38a) may not partially overlap each other as viewed in the axial direction. On the other hand, as shown in Fig. 6(b), for example, a configuration in which at least a portion of the first intermediate core region (36b) is adjacent to the second outer core region (39a) or the second inner core region (39b) in the axial direction is undesirable from the viewpoint of suppressing leakage magnetic flux.

[0059] 1, end plates 45 may be disposed at the upper and lower axial ends of the rotor core 32, as shown in Fig. 7, and bolts 46 may be provided that pass through the end plates 45 and the rotor core 32 in the axial direction to axially fasten the laminated steel plates that make up the rotor core 32, thereby improving the characteristics of the motor 20. For example, four bolts 46 may be provided at equal intervals in the circumferential direction so as to surround the drive shaft 40 when viewed in the axial direction.

[0060] <Magnet torque> In the configuration of this example shown in Fig. 5, the effect of the magnetic flux flowing in the axial direction and increasing the magnet torque is unique to an interior permanent magnet synchronous motor (IPMSM) structure in which the magnets 33 (magnets 33a, 33b) are embedded at a location radially away from the outer periphery of the rotor core 32 (rotor core portions 32a, 32b). To obtain this effect, the following two conditions must be satisfied:

[0061] The first condition is that a suitable core region must be provided between the outer diameter end of the magnet (33) and the outer peripheral surface of the rotor core (32). The shape of such a core region may be, for example, a shape that protrudes from the outside to the inside in the radial direction, such as the first outer core region (36a) of the first rotor portion (31a) shown in FIG. 3 or the second outer core region (39a) of the second rotor portion (31b) shown in FIG. 4. As shown in FIG. 3, the first rotor core portion (32a) has, in a cross section perpendicular to the axial direction, a shape that protrudes from the outside in the radial direction toward the third hole (outer hole) (35a) in which the first magnet (33a) is embedded. As shown in FIG. 4, the second rotor core portion (32b) has, in a cross section perpendicular to the axial direction, a shape that protrudes from the outside in the radial direction toward the fourth hole (38a) in which the second magnet (33b) is embedded.

[0062] The second condition is that the rotor core (32) (rotor core portions (32a, 32b)) is not magnetically saturated in the core regions (in this example, the first outer core region (36a) and the second outer core region (39a) shown in FIG. 5) through which magnetic flux flows in the axial direction. To achieve this, it is desirable that the magnetic force of the second magnet (33b) placed in the fourth hole portion (38a) is not strong. A magnet with a weak magnetic force is, for example, a ferrite magnet, and a magnet with a strong magnetic force is, for example, a neodymium magnet. In this example, both the first magnet (33a) and the second magnet (33b) are ferrite magnets.

[0063] <Reluctance torque> The motor (20) is an interior permanent magnet synchronous motor (IPMSM) with a permanent magnet inserted inside the rotor. The ease with which magnetic flux passes through the rotor of an IPMSM varies depending on the rotational position. In an IPMSM rotor, the direction in which magnetic flux passes easily (small magnetic resistance) is the q-axis, and the direction in which magnetic flux passes less easily (large magnetic resistance) is the d-axis. An IPMSM can output large torque by using the reluctance torque generated by the inductance deviation (magnetic resistance deviation) on the d- and q-axes. The inductance Lq in the q-axis direction is larger than the inductance Ld in the d-axis direction. Reluctance torque is proportional to (Ld - Lq), so the larger (Ld - Lq), the larger the reluctance torque.

[0064] The magnitude of the reluctance torque can be analytically calculated as follows:

[0065] First, the current I is input and the torque T (the sum of the magnet torque and reluctance torque) generated by the motor is calculated as follows: T=Pn(φa·I·cosβ+1 / 2(Lq-Ld)I 2 sin2β) It is calculated as follows.

[0066] Here, Pn is the number of pole pairs of the motor, φa is the armature interlinkage magnetic flux, and β is the leading phase angle of the current I from the q axis. Note that Pn is a known value determined by the motor structure, and β is a known value input during measurement. Ld=(vq-Ra·iq-ω·φa) / (ω·id) Lq=(Ra·id-vd) / (ω·iq) Since Ra is the resistance of the coil, it can be found with an ohmmeter. For ω (rotation speed), id (d-axis current), and iq (q-axis current), the values ​​input to the motor via the inverter are used. For vd (d-axis voltage) and vq (q-axis voltage), the values ​​are measured when the motor is driven under the desired operating conditions (ω, id, iq). φa is calculated by substituting the values ​​of ω and vq into the relational equation Vq = ω φa.

[0067] Next, the magnet torque is calculated by multiplying the separately calculated magnetic force strength of the permanent magnet by the input current conditions. Finally, the magnet torque is subtracted from the torque T to calculate the reluctance torque.

[0068] Alternatively, the magnitude of the reluctance torque may be experimentally calculated using an actual machine as follows. First, the torque T generated by the motor (actual machine) is adjusted to various values, and the current conditions at that time are read. Next, the magnet torque is calculated from the strength of the magnetic force of the permanent magnet, which is determined separately, and the current conditions at the given measurement conditions (torque T). Finally, the magnet torque is subtracted from the torque T to calculate the reluctance torque.

[0069] <Features of the First Embodiment> The motor (20) of the first embodiment includes a rotor (31) having a rotor core (32) and magnets (33) and rotating about a rotation axis (O), and a stator (21) disposed radially outward of the rotor (31) and having a stator core (22). The rotor (31) includes a first rotor portion (31a) radially facing the stator core (22) and generating reluctance torque, and a second rotor portion (31b) not radially facing the stator core (22) and disposed adjacent to the first rotor portion (31a) in the axial direction. The volume per unit length in the axial direction of the magnets (33) included in the second rotor portion (31b) is larger than the volume per unit length in the axial direction of the magnets (33) included in the first rotor portion (31a).

[0070] In the motor (20) of the first embodiment, the volume per unit axial length of the magnets (33) included in the second rotor portion (31b) that does not radially face the stator core (22) is increased, so that the increase in magnet torque can be made larger than the decrease in reluctance torque, thereby increasing the output torque of the motor (20).

[0071] Specifically, the first rotor portion (31a) generates both reluctance torque and magnet torque, and the second rotor portion (31b) mainly generates magnet torque. As will be described below, the configuration of this example can generate a larger torque than a motor configured using only the core shape of the first rotor core portion (32a), and can also generate a larger torque than a motor configured using only the core shape of the second rotor core portion (32b).

[0072] In a PMSM (permanent magnet synchronous motor) in which the rotor core extends axially further than the stator core, the reluctance torque generated by the motor decreases as the axial length of the portion of the rotor core that does not face the stator core (hereinafter referred to as the overhang) increases.

[0073] On the other hand, unlike reluctance torque, the magnet torque generated by the motor increases as the amount of overhang increases, for the following reason. The magnetic flux related to the magnet torque flows from the rotor to the stator (see Figure 5). The magnetic flux in the rotor core part that is not radially opposed to the stator core flows axially inside the rotor core, and then flows to the stator core. As the amount of overhang increases, the length of the magnetic path through which the magnetic flux flows increases, and although magnetic resistance increases, the increase in magnetic resistance is significantly suppressed compared to when the magnetic path is the gap between the stator core and the rotor core part that is not radially opposed to the stator core. Therefore, the magnet torque can be increased by using magnets embedded in the rotor core part that is not radially opposed to the stator core.

[0074] In the motor (20) of the first embodiment, the rotor core (32) of the first rotor portion (31a) may have a first hole (34a) in which the magnet (33) is arranged and a first core region (36a) located radially outward from the first hole (34a), and the rotor core (32) of the second rotor portion (31b) may have a second hole (37a) in which the magnet (33) is arranged and a second core region (39a) located radially outward from the second hole (37a), and the first core region (36a) and the second core region (39a) may form a magnetic path from the magnet (33) arranged in the second hole (37a) to the stator core (22). In this configuration, the magnet torque is increased by the magnet (33) arranged in the second hole (37a) of the second rotor portion (31b) that does not face the stator core (22) in the radial direction.

[0075] In the motor (20) of the first embodiment, the rotor core (32) may include a first rotor core portion (32a) and a second rotor core portion (32b), at least a portion of the first rotor core portion (32a) may be arranged in the first rotor portion (31a), and at least a portion of the second rotor core portion (32b) may be arranged in the second rotor portion (31b). The first rotor core portion (32a) may have substantially the same shape in cross section perpendicular to the axial direction and may have third hole portions (35a, 35b) in which the magnets (33) are arranged, and the second rotor core portion (32b) may have substantially the same shape in cross section perpendicular to the axial direction and may have fourth hole portions (38a) in which the magnets (33) are arranged. Furthermore, the volume per unit axial length of the magnets (33) arranged in the fourth holes (38a) of the second rotor core portion (32b) may be larger than the volume per unit axial length of the magnets (33) arranged in the third holes (35a, 35b) of the first rotor core portion (32a). In this manner, when at least a part of the second rotor core portion (32b) having a larger volume per unit axial length of the magnets (33) arranged in the second rotor portion (31b), the volume per unit axial length of the magnets (33) included in the second rotor portion (31b) can be increased.

[0076] In the motor (20) of the first embodiment, the number of the third holes (35a, 35b) may be greater than the number of the fourth holes (38a). In other words, the first rotor core portion (32a) radially facing the stator core (22) may have an IPMSM rotor shape in which two or more layers of magnets (33) are arranged in the radial direction, and the second rotor core portion (32b) not radially facing the stator core (22) may have an IPMSM rotor shape in which fewer layers of magnets (33) are arranged than in the first rotor core portion (32a). In this way, the first rotor core portion (32a) has a core shape that is likely to generate both reluctance torque and magnetic torque, and the second rotor core portion (32b) has a core shape that is likely to generate mainly magnetic torque. This allows the first rotor core portion (32a), which is prone to generating reluctance torque, to actively generate reluctance torque, and the second rotor core portion (32b), which is prone to generating reluctance torque, to actively generate magnet torque, thereby increasing the output torque of the motor (20).

[0077] In the motor (20) of the first embodiment, two or more third holes (35a, 35b) and one fourth hole (38a) may be adjacent to each other in the axial direction. This prevents magnetic flux from leaking through the first rotor core (32a) or the second rotor core (32b). In this case, the total radial length of the two or more third holes (35a, 35b) axially adjacent to the fourth hole (38a) may be greater than the radial distance between the stator core (22) and the rotor core (32). This makes the magnetic resistance of the magnetic path passing only through the rotor core (32) greater than the magnetic resistance of the magnetic path passing through both the rotor core (32) and the stator core (22). This reduces the magnetic flux leakage between the first rotor core (32a) and the second rotor core (32b).

[0078] In the motor (20) of the first embodiment, the first rotor core portion (32a) may have a shape that is convex from the radial outside toward the third hole portion (35a) in a cross section perpendicular to the axial direction, and the second rotor core portion (32b) may have a shape that is convex from the radial outside toward the fourth hole portion (38a) in a cross section perpendicular to the axial direction. In this way, a corresponding core region is secured between the outer diameter side end of the magnet (33) and the outer periphery of the rotor core (32), and magnetic flux from the magnet flows through the core region in the axial direction, thereby increasing the magnet torque.

[0079] In the motor (20) of embodiment 1, if the magnet (33) (second magnet (33b)) placed in the fourth hole portion (38a) is a ferrite magnet, magnetic saturation is less likely to occur in the core region where magnetic flux flows in the axial direction compared to when a magnet with strong magnetic force, such as a neodymium magnet, is placed.

[0080] (Modification 1 of Embodiment 1) In the first embodiment, two third holes (35a, 35b) are provided in the first rotor core portion (32a), but three or more third holes (35a, 35b, 35c) may be provided. FIGS. 8(a) to 8(d) show variations in the longitudinal cross-sectional configuration of the main parts of the motor (20) of this first modified example when three third holes (35a, 35b, 35c) are provided. In FIGS. 8(a) to 8(d), the same elements as those in the first embodiment are denoted by the same reference numerals.

[0081] In the first rotor core portion (32a) shown in FIG. 8(a), three third holes (35a, 35b, 35c) are arranged radially for one magnetic pole, and first magnets (33a) arranged magnetically in series are fitted into the third holes (35a, 35b, 35c). The three third holes (35a, 35b, 35c) and one fourth hole (38a) are adjacent to each other in the axial direction. The three third holes (35a, 35b, 35c) correspond to the three first holes (34a, 34b, 34c). The first rotor core portion (32a) is partitioned into four first core regions (36a, 36b, 36c, 36d) by the three third holes (35a, 35b, 35c).

[0082] 8(b) differs from that of FIG. 8(a) in that, in the second rotor core portion (32b), two fourth holes (38a, 38b) aligned radially are arranged for one magnetic pole, and second magnets (33b) aligned magnetically in series are fitted into each of the fourth holes (38a, 38b). Of the three third holes (35a, 35b, 35c), the two radially outer and central third holes (35a, 35b) are adjacent in the axial direction to the radially outer fourth hole (38a) of the two fourth holes (38a, 38b), and the radially inner third hole (35c) of the three third holes (35a, 35b, 35c) is adjacent in the axial direction to the radially inner fourth hole (38b) of the two fourth holes (38a, 38b). The two fourth holes (38a, 38b) correspond to the two second holes (37a, 37b). The second rotor core portion (32b) is partitioned into three second core regions (39a, 39b, 39c) by the two fourth holes (38a, 38b).

[0083] The configuration shown in FIG. 8(c) differs from that shown in FIG. 8(b) in that the second magnet (33b) is not disposed in the radially inner fourth hole portion (38b) of the two fourth hole portions (38a, 38b).

[0084] According to the configurations described above and shown in FIGS. 8(a) to 8(c), the same effects as those of the first embodiment can be obtained.

[0085] The configuration shown in Figure 8(d) differs from that shown in Figure 8(c) in that the radially inner fourth hole (38b) of the two fourth holes (38a, 38b) is not provided. Here, the first magnet (33a) embedded in the radially inner third hole (35c) of the three third holes (35a, 35b, 35c) is adjacent to the second rotor core portion (32b) (second core region (39b)) in the axial direction. Therefore, leakage magnetic flux is more likely to flow in the configuration shown in Figure 8(d).

[0086] (Modification 2 of Embodiment 1) The motor (20) of this modified example 2 differs from the first embodiment in that a non-magnetic material layer (47) is provided between the first rotor core portion (32a) and the second rotor core portion (32b), as shown in Fig. 9. In Fig. 9, the same elements as those of the first embodiment are denoted by the same reference numerals.

[0087] The non-magnetic material layer (47) may be made of, for example, stainless steel, brass, or resin (PPS (polyphenylene sulfide), PBT (polybutylene terephthalate), LCP (liquid crystal polymer), EP (epoxy resin), varnish, etc.).

[0088] The thickness (axial length) of the non-magnetic material layer (47) is desirably smaller than the shortest part of the gap length between the stator core (22) and the rotor core (32) so as not to interfere with the magnetic flux flowing in the axial direction.

[0089] According to the second modification, leakage of magnetic flux between the first rotor core portion (32a) and the second rotor core portion (32b) can be further suppressed.

[0090] (Modification 3 of Embodiment 1) The motor (20) of the third modified example differs from the first embodiment in that, as shown in Fig. 10, the first rotor core portion (32a) except for both axial ends thereof is disposed in the first rotor portion (31a), and both axial ends of the first rotor core portion (32a) and the entire second rotor core portion (32b) are disposed in the second rotor portion (31b). In Fig. 10, the same elements as those in the first embodiment are denoted by the same reference numerals.

[0091] In the motor (20) of the third modified example, the axial length of the first rotor core portion (32a) is longer than the axial length of the stator core (22), and the axial end portion of the first rotor core portion (32a) is positioned axially outward of the axial end portion of the stator core (22). In other words, the axial end portion of the first rotor core portion (32a) does not radially face the stator core (22).

[0092] In the motor (20) of the third modified example, as in the first embodiment, the volume per unit axial length of the second magnets (33b) embedded in the second rotor core portion (32b) is larger than the volume per unit axial length of the first magnets (33a) embedded in the first rotor core portion (32a). Therefore, the volume per unit axial length of the magnets (33) included in the second rotor portion (31b) is larger than that of the first rotor portion (31a), and therefore, the same effect as in the first embodiment can be obtained. The first hole portions (34a, 34b) of the first rotor portion (31a) correspond to the other portions of the third hole portions (35a, 35b) of the first rotor core portion (32a) except for both axial ends thereof, and the second hole portion (37a) of the second rotor portion (31b) corresponds to both axial ends of the third hole portions (35a, 35b) and the fourth hole portion (38a) of the second rotor core portion (32b).

[0093] Furthermore, in the third modification, even at an end of the first rotor core portion (32a) that does not face the stator core (32) in the radial direction, a corresponding reluctance torque is generated as long as the end is close to the stator core (32), and therefore, it is possible to increase the output torque compared to a configuration in which the entire first rotor core portion (32a) faces the stator core (32) in the radial direction. Specifically, as long as the axial length of the portion of the first rotor core portion (32a) that does not face the stator core (22) is approximately twice the gap length between the stator core (22) and the rotor core (32) or less, it is possible to generate reluctance torque even at the end of the first rotor core portion (32a) that does not face the stator core (32) in the radial direction.

[0094] (Fourth Modification of First Embodiment) 3 and 4, in the first embodiment, the third holes (35a, 35b) (first holes (34a, 34b)) and the fourth holes (38a) (second holes (37a)), in which the magnets (33) are respectively arranged, are formed in arc shapes that convex radially inward when viewed from the axial direction. However, the cross-sectional shapes of the third holes (35a, 35b) and the fourth holes (38a) are not particularly limited as long as a core region is secured for allowing magnetic flux from the magnets to flow in the axial direction from the second rotor portion (31b) (second rotor core portion (32b)) to the first rotor portion (31a) (first rotor core portion (32a)). 11(a) and 11(b) illustrate a case where the cross-sectional shapes of the third hole portions (35a, 35b) of the first rotor core portion (32a) and the fourth hole portion (38a) of the second rotor core portion (32b) in the motor (20) of Modified Example 4 include linearly extending portions. In FIGS. 11(a) and 11(b), the same elements as those in Embodiment 1 are denoted by the same reference numerals.

[0095] In the configuration shown in Figures 11(a) and 11(b), the third hole portions (35a, 35b) and the fourth hole portion (38a) have a first portion having a linear shape perpendicular to the radial direction when viewed from the axial direction, and a second portion extending from both ends of the first portion to the vicinity of the outer circumferential surface of the rotor core (32). In the configuration shown in Figures 11(a) and 11(b), as in the first embodiment, the first core region (first outer core region) (36a) of the first rotor portion (31a) and the second core region (second outer core region) (39a) of the second rotor portion (31b) form a magnetic path from the magnet (33) (second magnet (33b)) arranged in the second hole portion (37a) (fourth hole portion (38a)) to the stator core (22). This increases the magnet torque.

[0096] 12(a) to 12(d) show other variations of the cross-sectional configuration of the second rotor core portion (32b) in the motor (20) of Modified Example 4. In FIGS. 12(a) to 12(d), the same elements as those in the first embodiment are denoted by the same reference numerals. In the configurations shown in FIGS. 12(a) to 12(d), the fourth hole portion (38a) (second hole portion (37a)) has a shape other than a shape that is convex radially inward when viewed from the axial direction. In other words, the cross-sectional shape of the second rotor core portion (32b) shown in FIGS. 12(a) to 12(d) has a shape other than a shape that is convex radially outward toward the fourth hole portion (38a).

[0097] Specifically, in the configuration shown in Fig. 12(a), the fourth hole (38a) has an arc shape that is convex radially outward when viewed in the axial direction. In the configuration shown in Fig. 12(b), the fourth hole (38a) has a linear shape that is perpendicular to the radial direction when viewed in the axial direction. In the configuration shown in Fig. 12(c), the fourth hole (38a) has a linear shape that extends radially when viewed in the axial direction. In the configuration shown in Fig. 12(c), the fourth hole (38a) has a substantially V-shape that opens radially when viewed in the axial direction.

[0098] Although not shown, the third hole portions (35a, 35b) of the first rotor core portion (32a) have a shape corresponding to the fourth hole portion (38a) shown in Figures 12(a) to 12(d). Here, in the first rotor core portion (32a), one third hole portion (35a, 35b) may be provided for one magnetic pole as long as reluctance torque can be generated, but it is preferable to provide two or more third hole portions (35a, 35b).

[0099] Although the fourth modification has been described with reference to an example in which the rotor (31) has four poles, the number of poles of the rotor (31) is not particularly limited.

[0100] (Fifth Modification of First Embodiment) The motor (20) of this modified example 5 differs from the first embodiment in that, as shown in Figures 13(a) and 13(b), a gap (48) is provided in the second core region (second outer core region) (39a) near the outer circumferential surface of the second rotor core portion (32b) as a magnetic resistance structure that guides the magnetic flux of the magnet in the axial direction. In Figures 13(a) and 13(b), the same elements as those in the first embodiment are denoted by the same reference numerals.

[0101] In the motor (20) of the fifth modified example, the gaps (48) forming the magnetic resistance structure can increase the radial magnetic resistance near the outer circumferential surface of the second rotor core (32b). As a result, the magnetic flux from the second magnets (33) arranged in the fourth holes (38a) can be prevented from leaking from the outer circumferential surface of the second rotor core (32b) to the outside, and the magnetic flux can be reliably guided in the axial direction toward the first rotor core (32a).

[0102] (Embodiment 2) As shown in Fig. 14, the compressor (10) of the second embodiment is a rotary compressor. The compressor (10) includes a casing (11), the motor (20) of the first embodiment, a drive shaft (40), and a compression mechanism (50). In the following description, "upper," "lower," "right," and "left" refer to directions when the compressor (10) is viewed from the front (see arrows in Fig. 14). "Up" and "down" also refer to the axial direction of the drive shaft (40). "Right" and "left" refer to directions perpendicular to the axial direction and also refer to the radial direction of the motor (20) (or the casing (11)).

[0103] The casing (11) is a completely sealed container. The interior of the casing (11) is filled with high-pressure refrigerant discharged from the compression mechanism (50). The casing (11) is made of a metal material. The casing (11) has a body (12), a bottom (13), and a top (14). The body (12) is a cylindrical member extending in the vertical direction. The cylindrical axis of the body (12) is vertical. The bottom (13) closes the lower end of the body (12), and the top (14) closes the upper end of the body (12). The casing (11) accommodates, from top to bottom, a motor (20), a drive shaft (40), and a compression mechanism (50).

[0104] The rotation speed of the motor (20) is controlled by an inverter device. In other words, the compressor (10) is an inverter type compressor with a variable rotation speed. The stator (21) of the motor (20) is fixed to the inner circumferential surface of the body (12). The rotor (31) of the motor (20) rotates about the rotation axis (O) as described in the first embodiment. The drive shaft (40) extends downward from the motor (20). The drive shaft (40) is driven to rotate by the motor (20). The drive shaft (40) is rotatably supported by a bearing (41) provided below the motor (20).

[0105] The compression mechanism (50) includes a cylinder (51) and a piston (52) provided inside the cylinder (51). A cylinder chamber (53) is formed between the inner peripheral surface of the cylinder (51) and the outer peripheral surface of the piston (52). In the cylinder chamber (53), the piston (52) driven by the drive shaft (40) compresses the fluid.

[0106] The compressor (10) has a suction pipe (15) and a discharge pipe (16). The suction pipe (15) passes radially through the body (12) and communicates with the cylinder chamber (53). Low-pressure refrigerant is drawn into the cylinder chamber (53) through the suction pipe (15). The discharge pipe (16) passes axially through the top (14) and communicates with the interior space of the casing (11). The refrigerant compressed by the compression mechanism (50) flows through a core cut (not shown) of the motor (20) and is then discharged from the discharge pipe (16).

[0107] The compressor (10) of the second embodiment includes the motor (20) of the first embodiment, and therefore, power consumption can be reduced.

[0108] 14 is an example, and the compressor (10) is not limited to a rotary compressor. The compressor (10) may be a swing type, scroll type, screw type, turbo type, or other type of compressor.

[0109] (Embodiment 3) As shown in FIG. 15, the refrigeration system (1) of the third embodiment is an air conditioner. The air conditioner (1) may be dedicated to cooling or heating. The air conditioner (1) has a refrigerant circuit (1a) filled with a refrigerant. The refrigerant circuit (1a) has the compressor (10), radiator (2), expansion valve (3), and evaporator (4) of the second embodiment. The refrigerant circuit (1a) performs a vapor compression refrigeration cycle. The air conditioner (1) may be an air conditioner that switches between cooling and heating. In this case, the air conditioner (1) further has a switching mechanism (e.g., a four-way switching valve) that switches the circulation direction of the refrigerant.

[0110] In the refrigeration cycle, the refrigerant compressed by the compressor (10) dissipates heat to the air in the radiator (2). The refrigerant that has dissipated heat is reduced in pressure by the expansion valve (3) and evaporated in the evaporator (4). The evaporated refrigerant is drawn into the compressor (10) (see the arrow in FIG. 15).

[0111] In the radiator (2), heat is exchanged between the refrigerant flowing through the radiator (2) and air blown by a first fan (BL1) driven by a first motor (M1). In the evaporator (4), heat is exchanged between the refrigerant flowing through the evaporator (4) and air blown by a second fan (BL2) driven by a second motor (M2).

[0112] The air conditioner (refrigeration device) (1) of the third embodiment includes the compressor (10) of the second embodiment that is equipped with the motor (20) of the first embodiment, and therefore, power consumption can be reduced.

[0113] 15 is an example, and the refrigeration system (1) is not limited to an air conditioner. The refrigeration system (1) may be a water heater, a chiller unit, or a cooling system that cools the air inside a storage unit. The cooling system cools the air inside a refrigerator, a freezer, a container, or the like.

[0114] In addition, in the third embodiment, the motor (20) of the first embodiment is used as the motor for driving the compressor (10). However, in addition to this, or instead of this, the motor (20) may be used as the motor (M1) for driving the first fan (BL1) and / or the motor (M2) for driving the second fan (BL2).

[0115] (Other embodiments) In the above-described embodiments (including modified examples, the same applies hereinafter), the motor (20) has been described as an example of a rotary electric machine, but a configuration similar to that of the motor (20) may also be applied to a generator.

[0116] In each of the above-described embodiments, the second rotor portions (31b) are arranged on both axial sides of the rotor (31) so as not to face the stator core (22) in the radial direction. However, instead of this, the second rotor portions (31b) may be arranged on only one axial side. Furthermore, when the second rotor portions (31b) are arranged on both axial sides, the axial lengths of the second rotor portions (31b) on the two sides may be different.

[0117] Although the embodiments have been described above, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the claims. Furthermore, the above-described embodiments and modifications may be combined or substituted as appropriate. Furthermore, the terms "first," "second," "third," etc. in the specification and claims are used to distinguish the terms to which these terms are attached, and do not limit the number or order of those terms. [Industrial Applicability]

[0118] As described above, the present disclosure is useful for rotating electric machines, compressors, and refrigeration devices. [Explanation of symbols]

[0119] 20 Motors (rotating electrical machines) 21 Stator 22 stator core 31 Rotor 31a First rotor section 31b Second rotor section 32 rotor core 32a First rotor core 32b Second rotor core 33 Magnet 34a 1st hole 35a Outer hole (3rd hole) 35b Inner hole (3rd hole) 36a First outer core region (first core region) 37a 2nd hole 38a 4th hole 39a Second outer core region (second core region) O Rotation axis

Claims

1. a rotor (31) having a rotor core (32) and a magnet (33) and rotating about a rotation axis (O); a stator (21) disposed radially outside the rotor (31) and having a stator core (22); A rotating electric machine (20) comprising: The rotor (31) a first rotor portion (31a) radially opposed to the stator core (22) and generating a reluctance torque; a second rotor portion (31b) that does not face the stator core (22) in the radial direction and is arranged adjacent to the first rotor portion (31a) in the axial direction; and the volume per unit length in the axial direction of the magnets (33) included in the second rotor portion (31b) is larger than the volume per unit length in the axial direction of the magnets (33) included in the first rotor portion (31a); Rotating electrical machines.

2. The rotating electric machine (20) of claim 1, the rotor core (32) of the first rotor portion (31a) has a first hole portion (34a) in which the magnet (33) is arranged, and a first core region (36a) located radially outward of the first hole portion (34a), the rotor core (32) of the second rotor portion (31b) has a second hole portion (37a) in which the magnet (33) is arranged, and a second core region (39a) located radially outward of the second hole portion (37a), The first core region (36a) and the second core region (39a) form a magnetic path from the magnet (33) arranged in the second hole portion (37a) to the stator core (22). Rotating electrical machines.

3. The rotating electric machine (20) of claim 1, the rotor core (32) includes a first rotor core portion (32a) and a second rotor core portion (32b), At least a portion of the first rotor core portion (32a) is disposed in the first rotor portion (31a); At least a portion of the second rotor core portion (32b) is disposed in the second rotor portion (31b); the first rotor core portion (32a) has a cross section perpendicular to the axial direction that has substantially the same shape, and includes third hole portions (35a, 35b) in which the magnets (33) are disposed; the second rotor core portion (32b) has a cross section perpendicular to the axial direction that has substantially the same shape, and includes a fourth hole portion (38a) in which the magnet (33) is disposed; a volume per unit length in the axial direction of the magnet (33) arranged in the fourth hole portion (38a) of the second rotor core portion (32b) is larger than a volume per unit length in the axial direction of the magnet (33) arranged in the third hole portion (35a, 35b) of the first rotor core portion (32a); Rotating electrical machines.

4. 4. The rotating electric machine (20) of claim 3, the number of the third holes (35a, 35b) is greater than the number of the fourth holes (38a); Rotating electrical machines.

5. 4. The rotating electric machine (20) of claim 3, two or more of the third hole portions (35a, 35b) and one of the fourth hole portions (38a) are adjacent to each other in the axial direction; Rotating electrical machines.

6. The rotating electric machine (20) of claim 5, a total radial length of the two or more third hole portions (35a, 35b) axially adjacent to the fourth hole portion (38a) is greater than a radial distance between the stator core (22) and the rotor core (32); Rotating electrical machines.

7. 4. The rotating electric machine (20) of claim 3, the first rotor core portion (32a) has a shape that is convex from a radially outer side toward the third hole portion (35a) in a cross section perpendicular to the axial direction, the second rotor core portion (32b) has a shape that is convex from the radial outside toward the fourth hole portion (38a) in a cross section perpendicular to the axial direction; Rotating electrical machines.

8. 4. The rotating electric machine (20) of claim 3, the magnet (33) placed in the fourth hole (38a) is a ferrite magnet; Rotating electrical machines.

9. 4. The rotating electric machine (20) of claim 3, an axial end portion of the first rotor core portion (32a) does not face the stator core (22) in the radial direction; Rotating electrical machines.

10. A rotating electric machine (20) according to any one of claims 1 to 9. Compressor.

11. A rotating electric machine (20) according to any one of claims 1 to 9. Refrigeration equipment.

Images