Rotor, electric motor, compressor, blower, and refrigeration device

Abstract

A rotor (12) is provided with a rotor core (13), a first flux barrier (31), and a first conductor (51). The rotor core (13) comprises: an arc-shaped first outer peripheral surface (21) centered on the axis of a rotational shaft (11); and an arc-shaped second outer peripheral surface (22) positioned further inward in the radial direction than the first outer peripheral surface (21) and centered on the axis. The first flux barrier (31) penetrates the rotor core (13) in the axial direction. The first flux barrier (31) includes: an arc-shaped first gap portion (31a) centered on the axis and extending along the second outer peripheral surface (22); and a second gap portion (31b) linearly extending from an end of the first gap portion (31a) toward the first outer peripheral surface (21). The first conductor (51) is disposed in the first gap portion (31a).

Description

Rotors, electric motors, compressors, blowers, and refrigeration devices

[0001] The present disclosure relates to a rotor, an electric motor, a compressor, a blower, and a refrigeration device.

[0002] Patent Document 1 discloses a self-starting synchronous reluctance motor. The self-starting synchronous reluctance motor combines the features of an induction motor and a reluctance motor. The self-starting synchronous reluctance motor can be started by generating torque through squirrel-cage induction, so it can be started from a commercial power source and can achieve constant-speed operation by generating reluctance torque.

[0003] Special Publication No. 2022-537089

[0004] However, in the rotor structure of Patent Document 1, a squirrel-cage structure is formed by filling a conductive material into grooves on the outer periphery of the rotor core, which causes loss due to eddy currents.

[0005] An object of the present disclosure is to provide a rotor that can suppress losses caused by eddy currents generated in conductors.

[0006] A first aspect of the present disclosure is a rotor (12) configured to be rotatable about the axis of a rotating shaft (11). The rotor (12) includes a rotor core (13), a first flux barrier (31), and a first conductor (51). The rotor core (13) has a first outer peripheral surface (21) having an arc shape centered on the axis of the rotating shaft (11), and a second outer peripheral surface (22) located radially inward of the first outer peripheral surface (21) and having an arc shape centered on the axis. The first flux barrier (31) axially penetrates the rotor core (13). The first flux barrier (31) includes a first gap (31a) having an arc shape centered on the axis and extending along the second outer peripheral surface (22), and a second gap (31b) extending linearly from an end of the first gap (31a) toward the first outer peripheral surface (21). The first conductor (51) is disposed in the first gap (31a).

[0007] In the first aspect, a first gap (31 a) of the first flux barrier (31) is provided on the inner peripheral side of the second outer peripheral surface (22), which is a recess in the outer periphery of the rotor core (13), and the first conductor (51) is disposed in the first gap (31 a). This makes it possible to suppress loss due to eddy currents generated in the first conductor (51).

[0008] A second aspect of the present disclosure relates to the rotor of the first aspect, further including a second flux barrier (32) axially penetrating the rotor core (13) and a second conductor (52). The second flux barrier (32) includes: an arc-shaped third gap (32a) centered on the axis and extending along the second outer peripheral surface (22) alongside the first gap (31a); and a fourth gap (32b) extending linearly from an end of the third gap (32a) towards the first outer peripheral surface (21) alongside the second gap (31b). The third gap (32a) is located radially inward of the first gap (31a). The second conductor (52) is disposed in the fourth gap (32b).

[0009] In the second aspect, in addition to the first conductor (51) arranged in the first gap (31a) of the first flux barrier (31), the second conductor (52) is arranged in the fourth gap (32b) of the second flux barrier (32). This increases the torque generated by squirrel-cage induction, thereby increasing the starting torque.

[0010] A third aspect of the present disclosure is the second aspect, wherein the first conductor (51) is arranged radially inward of the second outer peripheral surface (22). The second conductor (52) is arranged radially inward of the second outer peripheral surface (22). When a virtual curve is drawn by extending the arc shape of the first gap portion (31 a) with the same curvature, the second conductor (52) is arranged at a position overlapping the virtual curve.

[0011] In the third aspect, since the first conductor (51) and the second conductor (52) are aligned, a starting torque can be generated smoothly. In addition, compared to when the second conductor (52) is arranged radially inward from the curve, the starting torque can be increased, and the generation of eddy currents can be suppressed compared to when the second conductor (52) is arranged radially outward from the curve.

[0012] A fourth aspect of the present disclosure is an electric motor including the rotor (12) according to any one of the first to third aspects.

[0013] In the fourth aspect, a motor with less loss can be realized.

[0014] A fifth aspect of the present disclosure is a compressor including the electric motor (10) of the fourth aspect.

[0015] In the fifth aspect, a motor with less loss can be realized.

[0016] A sixth aspect of the present disclosure is a blower including the electric motor (10) of the fourth aspect.

[0017] In the sixth aspect, a fan with low loss can be realized.

[0018] A seventh aspect of the present disclosure is a refrigeration system including the electric motor (10) of the fourth aspect.

[0019] In the seventh aspect, a refrigeration device with less loss can be realized.

[0020] FIG. 1 is a perspective view showing a schematic configuration of a rotor according to an embodiment, where (a) shows the rotor attached to a rotating shaft, (b) shows a state in which an end plate is removed from the secondary conductor, and (c) shows a state in which the secondary conductor is removed. FIG. 2 is a diagram showing variations of the cross-sectional configuration of the rotor according to an embodiment, where (a) shows the basic configuration, (b) shows a configuration in which multiple flux barriers are provided, (c) shows a modified shape of the secondary conductor, and (d) shows a modified number of layers of the secondary conductor. FIG. 3 is a diagram showing variations of the cross-sectional configuration of the rotor according to an embodiment, where (a) shows another modified number of layers of the secondary conductor, (b) shows a modified shape of the first outer peripheral surface, (c) shows a modified number of poles, and (d) shows a modified number of poles and number of layers of the secondary conductor. FIG. 4 is a diagram showing an example of a cross-sectional configuration of an electric motor according to an embodiment. FIG. 5 is a diagram explaining the operation of the electric motor according to an embodiment. FIG. 6 is a diagram explaining the operation of the electric motor according to an embodiment. FIG. 7 is a longitudinal cross-sectional view showing an example of the configuration of a compressor according to an embodiment. FIG. 8 is a piping diagram illustrating an example of the configuration of a refrigeration device according to an embodiment.

[0021] 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.

[0022] 1, the rotor (12) of this embodiment is configured to be rotatable together with the rotating shaft (11). The rotor (12) mainly includes a substantially cylindrical rotor core (13) and a secondary conductor (50) having a squirrel-cage structure.

[0023] In the present disclosure, the axis of the rotating shaft (11) is simply referred to as the "axis," the direction in which the axis extends, i.e., the direction of the rotation axis of the rotor (12), is referred to as the "axial direction," the direction perpendicular to the direction of the rotation axis of the rotor (12) is referred to as the "radial direction," and the direction around the rotation axis of the rotor (12) is referred to as the "circumferential direction." Furthermore, 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."

[0024] The rotor core (13) has a rotor core structure for a synchronous reluctance motor (SynRM). The rotor core (13) is formed by laminating electromagnetic steel sheets. The rotor core (13) may be made of, for example, an amorphous alloy, nanocrystals, or a powder magnetic core. A through hole (13a) extending in the axial direction (see FIG. 2) is provided in the radial center of the rotor core (13). With the rotating shaft (11) inserted into the through hole (13a), the rotor core (13) is fixed to the rotating shaft (11) by a lock nut (11b) with an end plate (11a) sandwiched therebetween. This allows the rotor (12) to rotate freely around its axis.

[0025] The secondary conductor (50) has a shape that extends in the axial direction. The secondary conductor (50) is inserted into the rotor core (13). The secondary conductor (50) is fixed to the rotor core (13) by placing a pair of end rings (50a) on both axial ends of the rotor core (13). The secondary conductor (50) and the end rings (50a) may be electrically connected by pouring metal into the gap between them. The end rings (50a) self-shorten the secondary conductor (50), forming a cage structure and realizing a self-starting function.

[0026] The secondary conductor 50 includes a first conductor 51 (see FIG. 2) extending in the axial direction, and may further include a second conductor 52 (see FIGS. 2 and 3) extending in the axial direction. The secondary conductor 50 is made of a conductive material such as aluminum or copper.

[0027] 2 and 3 show variations in the cross-sectional configuration of the rotor 12. The cross-sectional configuration of the rotor 12 is basically the same at any position in the axial direction, except for both axial ends where the end rings 50a are disposed.

[0028] In the basic configuration of the rotor (12) ( FIG. 2( a) ), the rotor core (13) has a first outer peripheral surface (21) having an arc shape centered on the axis, and a second outer peripheral surface (22) located radially inward of the first outer peripheral surface (21) and having an arc shape centered on the axis. The second outer peripheral surface (22) is a recess on the outer periphery of the rotor core (13). The rotor core (13) is provided with a first flux barrier (31) penetrating the rotor core (13) in the axial direction. The first flux barrier (31) includes a first gap portion (31 a) having an arc shape centered on the axis and extending along the second outer peripheral surface (22), and a second gap portion (31 b) extending linearly from an end of the first gap portion (31 a) toward the first outer peripheral surface (21). The first gap (31a) is provided on the inner peripheral side of a second outer peripheral surface (22) which is a recess in the outer periphery of the rotor core (13).

[0029] The first conductor (51) constituting the secondary conductor (50) is disposed in the first gap (31a) of the first flux barrier (31). By disposing the first conductor (51) radially inward of the second outer peripheral surface (22), which is a recess on the outer periphery of the rotor core (13), in this manner—in other words, by not disposing a conductor on the radial surface of the rotor core (13)—the generation of eddy currents can be suppressed. Specifically, when a motor is constructed using the rotor (12), the air gap between the second outer peripheral surface (22) of the rotor (12) and the stator is widened, making the first conductor (51) less susceptible to spatial harmonic magnetic flux, thereby suppressing the generation of eddy current loss. The first conductor (51) is made of a nonmagnetic material. No magnet is provided within the first flux barrier (31). In other words, no magnet is provided in the rotor (12).

[0030] The cross-sectional shape of the first conductor (51) is not particularly limited (see FIGS. 2(a) to 2(c) and 3(c)). For example, the first conductor (51) may be formed in an arc shape along the first gap (31a) (see FIGS. 2(a) and 2(b) and 3(c)), or may be formed from a number of rod-shaped portions extending in the axial direction (see FIG. 2(c)).

[0031] An electric conductor does not have to be arranged in the second gap (31b) of the first flux barrier (31). In particular, it is preferable not to arrange an electric conductor in a portion of the second gap (31b) located on the radially outer side (a portion close to the first outer peripheral surface (21)) in order to avoid an increase in loss due to eddy current. On the other hand, an electric conductor may be arranged in a portion of the second gap (31b) located on the radially inner side.

[0032] The rotor core (13) may be provided with a second flux barrier (32) penetrating the rotor core (13) in the axial direction (see FIGS. 2(b) to 2(d) and 3(a) to 3(d)). The second flux barrier (32) may be provided in a plurality of layers. The second flux barrier (32) includes: an arc-shaped third gap (32a) centered on the axis and extending along the second outer peripheral surface (22) alongside the first gap (31a); and a fourth gap (32b) extending linearly from an end of the third gap (32a) towards the first outer peripheral surface (21) alongside the second gap (31b). The third gap (32a) of the second flux barrier (32) is located radially inward of the first gap (31a) of the first flux barrier (31). When the first flux barrier (31) and the second flux barrier (32) are provided, a center rib (13b) may be provided so as to radially cross the flux barriers (31, 32) to reinforce the structure of the rotor core (13). In addition to providing one center rib (13b), a rib (13c) may be provided to define regions where the first conductor (51) and the second conductor (52) are formed, thereby further reinforcing the structure of the rotor core (13).

[0033] A second conductor (52) may be disposed in the fourth gap (32b) of the second flux barrier (32) (see (d) of FIG. 2 and (a), (b), and (d) of FIG. 3). In this case, the secondary conductor (50) is composed of a first conductor (51) and a second conductor (52). The second conductor (52) is made of a non-magnetic material. No magnet is disposed in the second flux barrier (32). That is, even when the first flux barrier (31) and the second flux barrier (32) are disposed, no magnet is disposed in the rotor (12). When a plurality of layers of second flux barriers (32) are disposed, the second conductor (52) may be disposed in only one fourth gap (32b) (see (d) of FIG. 2), or may be disposed in each of the plurality of fourth gaps (32b) (see (a), (b), and (d) of FIG. 3).

[0034] In order to avoid an increase in loss due to eddy current, it is preferable that the second conductor (52) is not arranged in a radially outer portion (close to the first outer peripheral surface (21)) of the fourth gap (32b) of the second flux barrier (32) (FIG. 2(d) and FIGS. 3(a), 3(b), and 3(d)). A conductor may or may not be arranged in the third gap (32a) of the second flux barrier (32). The cross-sectional shape of the second conductor (52) is not particularly limited.

[0035] The first conductor (51) and the second conductor (52) constituting the secondary conductor (50) are arranged radially inward of the second outer peripheral surface (22), and when a virtual curve is drawn by extending the arc shape of the first gap (31a) in which the first conductor (51) is arranged with the same curvature as the arc shape of the first gap (31a), in which the first conductor (51) is arranged, the second conductor (52) may be arranged at a position overlapping the curve (FIGS. 3(a) and 3(b)). In this way, by arranging the first conductor (51) and the second conductor (52) radially inward of the second outer peripheral surface (22), which is a recess in the outer periphery of the rotor core (13), in other words, by not arranging conductors on the radial surface of the rotor core (13), it is possible to suppress the generation of eddy currents.

[0036] The second gap (31b) of the first flux barrier (31) and the fourth gap (32b) of the second flux barrier (32) may be exposed to the first outer circumferential surface (21) of the rotor core (13) (FIG. 3(b)). In this case, in order to form the first conductor (51) and the second conductor (52) by casting, ribs (13c) that partition the formation areas of the first conductor (51) and the second conductor (52) may be provided in the first gap (31a) of the first flux barrier (31) and the fourth gap (32b) of the second flux barrier (32), respectively, so that metal can be poured into the space sandwiched between the ribs (13c). In this case, the end ring (50a) may also be formed integrally with the secondary conductor (50) so that metal can be poured into the space.

[0037] The number of poles of the rotor (12) is not particularly limited. For example, the number of poles may be two (see FIGS. 2(a) to 2(d) and 3(a) and 3(b)), or four (see FIGS. 3(c) and 3(d)). Even in a four-pole rotor (12), one or more layers of second flux barriers (32) may be provided (see FIGS. 3(c) and 3(d)). Second conductors (52) may be disposed in the fourth gaps (32b) of the second flux barriers (32) (see FIG. 3(d)). When multiple layers of second flux barriers (32) are provided, the second conductors (52) may be disposed in only one fourth gap (32b) or in each of the multiple fourth gaps (32b) (see FIG. 3(d)).

[0038] <Electric Motor> As shown in FIG. 4 , the electric motor (10) of this embodiment mainly includes the rotor (12) and a stator (40) that faces the rotor (12) across a predetermined radial gap. The stator (40) includes a stator core (41) and a plurality of windings (42). The stator core (41) includes a back yoke (41a) and a plurality of teeth (41b). The back yoke (41a) is formed in a substantially cylindrical shape. The plurality of teeth (41b) each extend radially inward from the inner circumferential surface of the back yoke (41a). The plurality of windings (42) are wound around the plurality of teeth (41b).

[0039] The configuration of the electric motor (10) shown in Figure 4 is an example, and the number of poles of the electric motor (10), the shape and number of teeth of the stator core (41), the winding method of the winding (42), etc. are not particularly limited.

[0040] As shown in Fig. 5, the electric motor (10) is started by passing an induced current through a secondary conductor (50), which serves as a rotor core of an induction motor, using a commercial power supply (50 Hz / 60 Hz). When the electric motor (10) is accelerated to a predetermined synchronous speed by squirrel-cage induction, a reluctance torque is generated by the synchronous reluctance motor structure (hereinafter referred to as synchronous machine structure) of the rotor core (13), and constant-speed operation (synchronous operation) is performed at the synchronous speed.

[0041] More specifically, when the electric motor (10) is connected to a commercial power supply, it starts due to the structure of an induction motor (hereinafter referred to as "induction motor structure") and accelerates to a rotation speed close to the synchronous speed, as shown in Figure 6. From start-up to the synchronous speed, the drive power supply frequency and the rotor frequency do not match (slip), so an induced current is generated in the secondary conductor (50), and an accelerating torque is generated due to the attraction and repulsion forces between the magnetic flux generated by the induced current and the magnetic flux of the current flowing in the winding (42) of the stator (40).

[0042] When the rotation speed approaches the synchronous speed, both the induction machine structure and the synchronous machine structure operate, and the motor accelerates to the synchronous speed. When the synchronous speed is reached, the slip described above disappears, and no induced current is generated in the secondary conductor (50). At this time, the frequency of the magnetic flux flowing through the rotor core (13) matches the power supply frequency of the stator (40), so synchronous operation is performed only with the synchronous machine structure.

[0043] In addition to the power running operation in the rotational speed range below the synchronous speed, the induction motor structure also includes regenerative operation in the rotational speed range above the synchronous speed. When the rotor (12) accelerates due to fluctuations on the load side during operation of the electric motor (10) and the rotational speed exceeds the synchronous speed, the electric motor (10) enters a regenerative operation state. In this case, the electric motor (10) operates as a generator, absorbing the kinetic energy of the rotor (12) and the load and sending power back to the power source.

[0044] As described above, the electric motor (10) has two advantages: high efficiency as a synchronous reluctance motor and startability from a commercial power source as an induction motor.

[0045] In the electric motor (10), by providing the second outer peripheral surface (22), which is a recess on the outer periphery of the rotor core (13), in a path through which magnetic flux is difficult to pass, it is possible to further increase the magnetic resistance and increase the salient pole ratio of the electric motor (10), thereby improving the performance of the electric motor (10).

[0046] In the electric motor (10), by configuring the secondary conductor (50) so that the magnetic flux of the stator (40) (air gap) does not easily pass through the secondary conductor (50), it is possible to reduce losses caused by eddy currents generated in the secondary conductor (50).

[0047] In the rotor core (13) of the electric motor (10), when a curve is drawn imaginarily by extending the arc shape of the first gap (31a) in which the first conductor (51) is disposed, with the same curvature as the arc shape of the first gap (31a), the second conductor (52) is preferably disposed at a position overlapping the curve (FIGS. 3(a) and 3(b)). In this way, when the secondary conductor (50) is disposed in the gaps (31a, 32b) so as to be aligned (concentrically) with the arc of the outer circumferential surface of the rotor core (13), the starting torque of the electric motor (10) can be maximized.

[0048] In the electric motor (10), the starting performance of the electric motor (10) can be improved by increasing the amount of the secondary conductor (50) (specifically, the first conductor (51)) provided near the second outer peripheral surface (22), which is a recess in the outer periphery of the rotor core (13).

[0049] <Compressor> As shown in FIG. 7, the compressor (CC) of this embodiment mainly includes the above-described electric motor (10), a casing (CC1), and a compression mechanism (CC2).

[0050] The casing (CC1) accommodates the compression mechanism (CC2) and the electric motor (10). In this example, the casing (CC1) is formed in a cylindrical shape that extends in the vertical direction and is closed at both ends. The casing (CC1) is provided with a suction pipe (CC11) and a discharge pipe (CC12). The suction pipe (CC11) passes through a body portion of the casing (CC1) and is connected to the compression mechanism (CC2). The discharge pipe (CC12) passes through an upper portion of the casing (CC1) and is in communication with the interior space of the casing (CC1).

[0051] The compression mechanism (CC2) compresses the fluid. In this example, the compression mechanism (CC2) is disposed below the electric motor (10). The compression mechanism (CC2) compresses the fluid drawn in through the suction pipe (CC11) and discharges the compressed fluid into the internal space of the casing (CC1). The fluid discharged into the internal space of the casing (CC1) is discharged through the discharge pipe (CC12). In this example, the compression mechanism (CC2) is a rotary compression mechanism.

[0052] The rotary shaft (11) connects the electric motor (10) and the compression mechanism (CC2). In this example, the rotary shaft (11) extends in the vertical direction. The electric motor (10) drives the rotary shaft (11) to rotate. The rotation of the rotary shaft (11) drives the compression mechanism (CC2).

[0053] 7 is an example, and the compressor (CC) is not limited to a rotary compressor as shown in the example. The compressor (CC) may be a swing type, scroll type, screw type, turbo type, or other type of compressor.

[0054] <Refrigeration Device> FIG. 8 illustrates the configuration of a refrigeration device (RR) according to this embodiment. The refrigeration device (RR) includes a refrigerant circuit (RR1) through which a refrigerant circulates. Specifically, the refrigerant circuit (RR1) includes a compressor (CC) having an electric motor (10), a first heat exchanger (RR5), a second heat exchanger (RR6), a pressure reduction mechanism (RR7), and a four-way switching valve (RR8). In this example, the expansion mechanism (RR7) is an electronic expansion valve. The refrigerant circuit (RR1) performs a vapor compression refrigeration cycle. For example, the first heat exchanger (RR5) is a heat source heat exchanger and is provided outdoors. The second heat exchanger (RR6) is a utilization heat exchanger and is provided indoors.

[0055] In the first heat exchanger (RR5), heat is exchanged between the refrigerant flowing through the first heat exchanger (RR5) and the air blown by the first fan (BL1). In the second heat exchanger (RR6), heat is exchanged between the refrigerant flowing through the second heat exchanger (RR6) and the air blown by the second fan (BL2).

[0056] The discharge side of the compressor (CC) is connected to the first port (P1) of the four-way switching valve (RR8). The suction side of the compressor (CC) is connected to the second port (P2) of the four-way switching valve (RR8). The gas end of the first heat exchanger (RR5) is connected to the third port (P3) of the four-way switching valve (RR8). The liquid end of the first heat exchanger (RR5) is connected to the liquid end of the second heat exchanger (RR6) via the expansion mechanism (RR7). The gas end of the second heat exchanger (RR6) is connected to the fourth port (P4) of the four-way switching valve (RR8).

[0057] The four-way switching valve (RR8) can be switched between a first state (state shown by solid lines in FIG. 8) in which the first port (P1) and the third port (P3) are connected and the second port (P2) and the fourth port (P4) are connected, and a second state (state shown by dashed lines in FIG. 8) in which the first port (P1) and the fourth port (P4) are connected and the second port (P2) and the third port (P3) are connected.

[0058] When the four-way switching valve (RR8) is in the first state, the refrigerant discharged from the compressor (CC) releases heat in the first heat exchanger (RR5), is decompressed in the expansion mechanism (RR7), and then absorbs heat in the second heat exchanger (RR6). The refrigerant flowing out of the second heat exchanger (RR6) is drawn into the compressor (CC).

[0059] When the four-way switching valve (RR8) is in the second state, the refrigerant discharged from the compressor (CC) releases heat in the second heat exchanger (RR6), is decompressed in the expansion mechanism (RR7), and then absorbs heat in the first heat exchanger (RR5). The refrigerant flowing out of the first heat exchanger (RR5) is drawn into the compressor (CC).

[0060] The configuration of the refrigeration unit (RR) shown in FIG. 8 is an example, and the refrigeration unit (RR) may be an air conditioner that switches between cooling and heating. Alternatively, the refrigeration unit (RR) may be a dedicated cooling unit or a dedicated heating unit. In this case, the four-way switching valve (RR8) may be omitted from the refrigeration unit (RR). The refrigeration unit (RR) may also be a water heater, a chiller unit, a cooling unit that cools the air inside a storage unit, or the like. A cooling unit cools the air inside a refrigerator, a freezer, a container, or the like.

[0061] In addition, in this example, the electric motor (10) is used as the motor that drives the compressor (CC). However, in addition to this, or instead of this, the electric motor (10) may be used as the motor (M1) that drives the first fan (BL1) and / or the motor (M2) that drives the second fan (BL2).

[0062] <Features of the Embodiment> The rotor (12) of this embodiment is configured to be rotatable around the axis of the rotating shaft (11). The rotor (12) includes a rotor core (13), a first flux barrier (31), and a first conductor (51). The rotor core (13) has a first outer peripheral surface (21) that is arc-shaped and centered on the axis of the rotating shaft (11), and a second outer peripheral surface (22) that is arc-shaped and located radially inward of the first outer peripheral surface (21) and centered on the axis. The first flux barrier (31) penetrates the rotor core (13) in the axial direction. The first flux barrier (31) includes a first gap (31a) that is arc-shaped and centered on the axis and extends along the second outer peripheral surface (22), and a second gap (31b) that extends linearly from an end of the first gap (31a) toward the first outer peripheral surface (21). The first conductor (51) is disposed in the first gap (31a).

[0063] In the rotor (12) of this embodiment, a first gap (31 a) of the first flux barrier (31) is provided on the inner peripheral side of the second outer peripheral surface (22), which is a recess in the outer periphery of the rotor core (13), and the first conductor (51) is disposed in the first gap (31 a). This makes it possible to suppress loss due to eddy currents generated in the first conductor (51).

[0064] The rotor (12) of this embodiment may further include a second flux barrier (32) that penetrates the rotor core (13) in the axial direction, and a second conductor (52). The second flux barrier (32) may include a third gap (32a) that has an arc shape and is centered on the axis and extends along the second outer peripheral surface (22) parallel to the first gap (31a), and a fourth gap (32b) that extends linearly from an end of the third gap (32a) toward the first outer peripheral surface (21) parallel to the second gap (31b). The third gap (32a) may be located radially inward of the first gap (31a). The second conductor (52) may be disposed in the fourth gap (32b). In this way, when the second conductor (52) is arranged in the fourth gap (32b) of the second flux barrier (32) in addition to the first conductor (51) arranged in the first gap (31a) of the first flux barrier (31), the torque generated by squirrel-cage induction can be increased, and therefore the starting torque can also be increased.

[0065] In the rotor (12) of this embodiment, the first conductor (51) and the second conductor (52) may be disposed radially inward of the second outer peripheral surface (22). When a virtual curve is drawn by extending the arc shape of the first gap (31a) with the same curvature, the second conductor (52) may be disposed at a position overlapping the curve. By aligning the first conductor (51) and the second conductor (52) in this manner, starting torque can be generated smoothly. Furthermore, compared to when the second conductor (52) is disposed radially inward of the curve, starting torque can be increased, and eddy current generation can be suppressed compared to when the second conductor (52) is disposed radially outward of the curve.

[0066] The electric motor (10) of this embodiment includes the rotor (12), and therefore, loss can be reduced.

[0067] The compressor (CC) of this embodiment includes the electric motor (10), and therefore, loss can be reduced.

[0068] The sending machines (BL1, BL2) of this embodiment include the electric motors (10), which makes it possible to reduce losses.

[0069] The refrigeration system (RR) of this embodiment includes the electric motor (10), and therefore, loss can be reduced.

[0070] (Other Embodiments) In the rotor (12) of the above-described embodiment (including modified examples; the same applies hereinafter), the second flux barrier (32) in which no conductor is arranged in the arc-shaped third gap (32a) is arranged radially inside the first flux barrier (31) in which the first conductor (51) is arranged in the arc-shaped first gap (31a). However, instead of this, the first flux barrier (31) may be arranged radially inside the second flux barrier (32). However, in order to increase the amount of secondary conductors (50) provided near the second outer circumferential surface (22) of the rotor core (13) in order to improve the starting performance of the electric motor (10), it is preferable to arrange the second flux barrier (32) radially inside the first flux barrier (31).

[0071] In the rotor (12) of the above-described embodiment (including modified examples; the same applies hereinafter), the arc-shaped first gap (31 a) and the linear second gap (31 b) are in communication with each other in the first flux barrier (31), and the arc-shaped third gap (32 a) and the linear fourth gap (32 b) are in communication with each other in the second flux barrier (32). However, instead of this, ribs may be provided between the first gap (31 a) and the second gap (31 b) and / or between the third gap (32 a) and the fourth gap (32 b) for the purpose of ensuring the strength of the rotor core (13) or for the formation (e.g., casting) of the secondary conductor (50), etc.

[0072] 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 between terms to which these terms are attached, and do not limit the number or order of those terms.

[0073] As described above, the present disclosure is useful for rotors, electric motors, compressors, blowers, and refrigeration devices.

[0074] 10 electric motor 11 rotating shaft 12 rotor 13 rotor core 21 first outer peripheral surface 22 second outer peripheral surface 31 first flux barrier 31a first gap 31b second gap 32 second flux barrier 32a third gap 32b fourth gap 51 first conductor 52 second conductor CC compressor BL1, BL2 blower RR refrigeration device

Claims

1. A rotor (12) configured to be rotatable around the axis of a rotating shaft (11), comprising: a rotor core (13) having a first outer peripheral surface (21) of an arc shape centered on the axis of the rotating shaft (11), and a second outer peripheral surface (22) of an arc shape located radially inward of the first outer peripheral surface (21) and centered on the axis; a first flux barrier (31) penetrating the rotor core (13) in the axial direction; and a first conductor (51), wherein the first flux barrier (31) includes a first gap portion (31 a) of an arc shape centered on the axis and extending along the second outer peripheral surface (22), and a second gap portion (31 b) extending linearly from an end of the first gap portion (31 a) toward the first outer peripheral surface (21), and the first conductor (51) is disposed in the first gap portion (31 a).

2. A rotor according to claim 1, further comprising: a second flux barrier (32) penetrating the rotor core (13) in the axial direction; and a second conductor (52), wherein the second flux barrier (32) includes: an arc-shaped third gap (32a) centered on the axis and extending alongside the first gap (31a) along the second outer peripheral surface (22); and a fourth gap (32b) extending linearly alongside the second gap (31b) from an end of the third gap (32a) towards the first outer peripheral surface (21), wherein the third gap (32a) is located radially inward of the first gap (31a), and the second conductor (52) is arranged in the fourth gap (32b).

3. A rotor according to claim 2, wherein the first conductor (51) is arranged radially inward of the second outer peripheral surface (22), the second conductor (52) is arranged radially inward of the second outer peripheral surface (22), and when a virtual curve is drawn by extending the arc shape of the first gap portion (31a) with the same curvature, the second conductor (52) is arranged in a position overlapping the curve.

4. An electric motor comprising a rotor (12) according to any one of claims 1 to 3.

5. A compressor comprising the electric motor (10) of claim 4.

6. A blower comprising the electric motor (10) of claim 4.

7. A refrigeration system comprising the electric motor (10) of claim 4.

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