JP7154373B2 - Electric motors, compressors, and air conditioners - Google Patents

Description

The present invention relates to electric motors.

Generally, an electric motor is used in which a gap is provided between the stator windings and the stator core (see Patent Document 1, for example). Providing a separation between the stator windings and the stator core reduces leakage current from the stator windings to the stator core.

JP 2017-099044 A

However, when the area of the stator core in the plane orthogonal to the axial direction is reduced, the stator core is likely to be magnetically saturated, and iron loss is likely to increase in the stator core. As a result, the efficiency of the electric motor (also referred to as motor efficiency) may decrease.

SUMMARY OF THE INVENTION It is an object of the present invention to increase the efficiency of the electric motor.

An electric motor according to one aspect of the present invention includes:
a stator having axially laminated first and second stator cores and slots in which stator windings are arranged;
a first rotor core radially facing the first stator core, a second rotor core radially facing the second stator core, and at least one permanent magnet having a first portion and a second portion; a rotor disposed inside the stator;
the stator has recesses facing the slots that do not contact the stator windings;
The first rotor core has at least one first hole having a first magnet arrangement portion in which the first portion is arranged and a first flux barrier portion communicating with the first magnet arrangement portion,
The second rotor core has at least one second hole having a second magnet arrangement portion in which the second portion is arranged and a second flux barrier portion communicating with the second magnet arrangement portion,
The residual magnetic flux density of the first portion is lower than the residual magnetic flux density of the second portion.
An electric motor according to another aspect of the present invention includes:
a stator having axially laminated first and second stator cores and slots in which stator windings are arranged;
a first rotor core radially facing the first stator core, a second rotor core radially facing the second stator core, and at least one permanent magnet having a first portion and a second portion; a rotor disposed inside the stator;
with
the stator has recesses facing the slots that do not contact the stator windings;
the first rotor core has at least one first hole having a first magnet arrangement portion in which the first portion is arranged;
the second rotor core has at least one second hole having a second magnet arrangement portion in which the second portion is arranged;
The residual magnetic flux density of the first portion is lower than the residual magnetic flux density of the second portion.
A compressor according to another aspect of the present invention comprises:
a closed container;
a compression device disposed within the closed vessel;
and the electric motor that drives the compression device.
An air conditioner according to another aspect of the present invention includes
the compressor;
and a heat exchanger.

According to the present invention, the efficiency of the electric motor can be enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows roughly the structure of the electric motor which concerns on Embodiment 1 of this invention. It is a sectional view showing roughly the structure of an electric motor. FIG. 3 is a cross-sectional view along line C3-C3 in FIG. 2; 3 is a plan view schematically showing the structure of a first rotor core; FIG. FIG. 4 is a plan view schematically showing the structure of a second rotor core; It is a perspective view which shows roughly the structure of one part of a stator. FIG. 2 is a plan view schematically showing the structure of part of the stator shown in FIG. 1; FIG. 4 is a plan view schematically showing the structure of part of the stator shown in FIG. 3; FIG. 4 is a diagram showing another structure of the first stator core (specifically, teeth of the first stator core); FIG. 6 is a cross-sectional view schematically showing the structure of a compressor according to Embodiment 2 of the present invention; FIG. 3 is a diagram schematically showing the configuration of a refrigerating and air-conditioning apparatus according to Embodiment 3 of the present invention;

Embodiment 1.
In the xyz orthogonal coordinate system shown in each figure, the z-axis direction (z-axis) indicates a direction parallel to the axis Ax of the electric motor 1, and the x-axis direction (x-axis) is orthogonal to the z-axis direction (z-axis). The y-axis direction (y-axis) indicates a direction orthogonal to both the z-axis direction and the x-axis direction. The axis Ax is the center of rotation of the rotor 2 . The direction parallel to the axis Ax is also referred to as "the axial direction of the rotor 2" or simply "the axial direction". The radial direction is the radial direction of the rotor 2 and the direction perpendicular to the axis Ax. The xy plane is a plane perpendicular to the axial direction. An arrow D1 indicates a circumferential direction about the axis Ax. The circumferential direction of the rotor 2 or stator 3 is also simply referred to as "circumferential direction".

FIG. 1 is a sectional view schematically showing the structure of electric motor 1 according to Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view schematically showing the structure of the electric motor 1. As shown in FIG.
FIG. 3 is a cross-sectional view along line C3-C3 in FIG.

The electric motor 1 has a rotor 2 and a stator 3 . The electric motor 1 is, for example, a permanent magnet synchronous motor (also referred to as a brushless DC motor) such as a permanent magnet embedded electric motor.

The rotor 2 is rotatably arranged inside the stator 3 . The rotor 2 has a rotor core 20 , at least one permanent magnet 23 and a shaft 26 . In this embodiment, the rotor 2 is a permanent magnet embedded rotor. As shown in FIG. 2, the rotor core 20 has at least one first rotor core 21 and at least one second rotor core 22 adjacent to the first rotor core 21 in the axial direction.

As shown in FIG. 2, each permanent magnet 23 has a first portion 231 and a second portion 232 . In this embodiment, each permanent magnet 23 is divided into a first portion 231 and a second portion 232 . However, each permanent magnet 23 may not be divided into the first portion 231 and the second portion 232 . That is, the first portion 231 and the second portion 232 may be integrated with each other.

The stator 3 has a stator core 30 , at least one stator winding 37 , at least one slot 35 ( FIG. 6 ) in which the stator winding 37 is arranged, and at least one recess 36 . The stator core 30 has a first stator core 31 and a second stator core 32 that are axially laminated.

In the example shown in FIG. 2 , the rotor core 20 has two first rotor cores 21 and one second rotor core 22, and the second rotor core 22 is arranged between the two first rotor cores 21. For example, the length of one first rotor core 21 in the axial direction is 7.5 mm, and the length of the second rotor core 22 in the axial direction is 15 mm. However, the number of first rotor cores 21 and second rotor cores 22 is not limited to the example shown in FIG. 2, and the arrangement of first rotor cores 21 and second rotor cores 22 is not limited to the example shown in FIG.

An air gap exists between the rotor 2 (specifically, the outer peripheral surface of the rotor core 20 ) and the stator 3 . The air gap between rotor 2 and stator 3 is, for example, 0.3 mm to 1 mm. When a current having a frequency synchronized with the commanded rotational speed is supplied to the stator winding 37, a rotating magnetic field is generated in the stator 3, causing the rotor 2 to rotate.

The rotor core 20 (that is, the first rotor core 21 and the second rotor core 22) is fixed to the shaft 26 by a fixing method such as shrink fitting or press fitting. When the rotor 2 rotates, rotational energy is transmitted from the first rotor core 21 and the second rotor core 22 to the shaft 26 .

FIG. 4 is a plan view schematically showing the structure of the first rotor core 21. As shown in FIG.
The first rotor core 21 faces the first stator core 31 of the stator 3 in the radial direction. The first rotor core 21 has a plurality of magnetic steel sheets 210 laminated in the axial direction. These electromagnetic steel plates 210 are fixed to each other by caulking. Each of the plurality of electromagnetic steel sheets 210 is punched into a predetermined shape. Each thickness of the plurality of electromagnetic steel sheets 210 is, for example, 0.1 mm or more and 0.7 mm or less. In the present embodiment, the thickness of each of the plurality of electromagnetic steel sheets 210 is 0.35 mm.

The first rotor core 21 has at least one first hole 211 and a first shaft insertion hole 214 in which the shaft 26 is arranged. In the example shown in FIG. 4, the first rotor core 21 has six first holes 211 arranged in the circumferential direction. That is, in the example shown in FIG. 4 , “at least one first hole 211 ” means six first holes 211 . The radius of the first shaft insertion hole 214 is, for example, 2 mm to 3 mm.

Each first hole 211 has at least one first magnet arrangement portion 212 in which the permanent magnets 23 are arranged, and at least one first flux barrier portion 213 communicating with the first magnet arrangement portion 212 . Specifically, the first portion 231 of each permanent magnet 23 is arranged in each first magnet arrangement section 212 . Each first hole 211 is, for example, a through hole. Each first hole 211 has a V shape in the xy plane. Specifically, first flux barrier portions 213 for reducing leakage magnetic flux are present at both ends of each first hole 211, and at least one first magnet arrangement portion is provided between the two first flux barrier portions 213. 212 exist.

Each first flux barrier portion 213 has a length in the circumferential direction. The distance between two first flux barrier portions 213 adjacent to each other in the circumferential direction is equal to or greater than the thickness of electromagnetic steel sheet 210 .

A portion of the electromagnetic steel sheet 210 existing outside the first flux barrier portion 213 in the radial direction, that is, a region between the outer peripheral surface of the rotor core 20 and the first flux barrier portion 213 is a short circuit of the magnetic flux from the permanent magnet 23. It is a thin part that reduces The width of this thin portion in the radial direction is, for example, equal to or greater than the thickness of each electromagnetic steel plate 210 of the rotor core 20 . This reduces short circuits between adjacent magnetic poles.

FIG. 5 is a plan view schematically showing the structure of the second rotor core 22. As shown in FIG.
The second rotor core 22 faces the second stator core 32 of the stator 3 in the radial direction. The second rotor core 22 has a plurality of magnetic steel sheets 220 laminated in the axial direction. These electromagnetic steel plates 220 are fixed to each other by caulking. Each of the plurality of electromagnetic steel sheets 220 is punched into a predetermined shape. Each thickness of the plurality of electromagnetic steel sheets 220 is, for example, 0.1 mm or more and 0.7 mm or less. In this embodiment, the thickness of each of the plurality of electromagnetic steel sheets 220 is 0.35 mm.

The second rotor core 22 has at least one second hole 221 and a second shaft insertion hole 224 in which the shaft 26 is arranged. In the example shown in FIG. 5, the second rotor core 22 has six second holes 221 arranged in the circumferential direction. That is, in the example shown in FIG. 5 , “at least one second hole 221 ” means six second holes 221 . The radius of the second shaft insertion hole 224 is the same as the radius of the first shaft insertion hole 214, eg, 2 mm to 3 mm.

Each second hole 221 has at least one second magnet placement portion 222 in which the permanent magnets 23 are arranged, and at least one second flux barrier portion 223 communicating with the second magnet placement portion 222 . Specifically, the second portion 232 of each permanent magnet 23 is arranged in each second magnet arrangement portion 222 . Each second flux barrier portion 223 has a length in the circumferential direction. The distance between two second flux barrier portions 223 that are adjacent to each other in the circumferential direction is equal to or greater than the thickness of electromagnetic steel sheet 220 .

Each second hole 221 is, for example, a through hole. Each second hole 221 has a V shape in the xy plane. Specifically, at both ends of each second hole 221, there are second flux barrier portions 223 that reduce leakage magnetic flux, and between the two second flux barrier portions 223, there is at least one second magnet placement portion. 222 exists. Each second hole 221 communicates with each first hole 211 of the first rotor core 21 .

A portion of the electromagnetic steel sheet 220 existing outside the second flux barrier portion 223 in the radial direction, that is, a region between the outer peripheral surface of the rotor core 20 and the second flux barrier portion 223 is a short circuit of the magnetic flux from the permanent magnet 23. It is a thin part that reduces The width of this thin portion in the radial direction is equal to or greater than the thickness of the electromagnetic steel sheet 220 . This reduces short circuits between adjacent magnetic poles.

The number of first holes 211 of the first rotor core 21 is the same as the number of magnetic poles of the rotor 2 . Therefore, the number of second holes 221 of the second rotor core 22 is also the same as the number of magnetic poles of the rotor 2 . As described above, each first hole 211 and each second hole 221 have a V shape in the xy plane. Two permanent magnets 23 are arranged in a pair of first hole 211 and second hole 221 communicating with each other. Each permanent magnet 23 is a planar magnet. Therefore, the two permanent magnets 23 are arranged in a V shape in the xy plane and protrude radially inward. Two permanent magnets 23 arranged in a pair of first holes 211 and second holes 221 form one magnetic pole of the rotor 2 .

As shown in FIG. 2 , the first portion 231 of the permanent magnet 23 is arranged in the first magnet placement portion 212 of the first hole 211 . As shown in FIG. 2 , the second portion 232 of the permanent magnet 23 is arranged in the second magnet placement portion 222 of the second hole 221 .

The first portion 231 and the second portion 232 are, for example, different types of magnets. The residual magnetic flux density of the first portion 231 is lower than that of the second portion 232 .

When each permanent magnet 23 is a rare earth magnet, the concentration of heavy rare earth elements such as dysprosium (Dy) and terbium (Tb) in at least a portion of the first portion 231 is higher than the concentration of rare earth elements. In other words, if each permanent magnet 23 is a rare earth magnet, the first portion 231 includes a region with a higher heavy rare earth element concentration than the heavy rare earth element concentration in the second portion 232 . In the permanent magnet 23, as the heavy rare earth element concentration increases, the coercive force increases and the residual magnetic flux density decreases. For example, in each permanent magnet 23, which is a rare earth magnet, the first portion 231 includes a region with a heavy rare earth element concentration of 4% by weight, and the heavy rare earth element concentration in the second portion 232 is 1% by weight.

Combinations of the types of magnets of the first portion 231 and the types of magnets of the second portion 232 are, for example, the following combinations.

The first portion 231 is, for example, a ferrite magnet. In this case, the second part 232 is, for example, a neodymium magnet.

The first portion 231 is, for example, a samarium-cobalt magnet. In this case, the second part 232 is, for example, a neodymium magnet.

The first portion 231 is, for example, a ferrite magnet. In this case, the second part 232 is, for example, a samarium-cobalt magnet.

The first portion 231 is, for example, a ferrite bond magnet. In this case, the second part 232 is, for example, a sintered ferrite magnet.

As long as the residual magnetic flux density of the first portion 231 is lower than the residual magnetic flux density of the second portion 232, the combination of the magnet type of the first portion 231 and the magnet type of the second portion 232 is not limited to the above example.

For example, first portion 231 and second portion 232 may be the same type of magnet. For example, the first portion 231 is a sintered neodymium magnet, and the second portion 232 is also a sintered neodymium magnet. In this case, the residual magnetic flux density of the first portion 231, which is a neodymium sintered magnet, is 1.31 [T] to 1.35 [T], and the residual magnetic flux density of the second portion 232, which is a neodymium sintered magnet, is 1. .4 [T] to 1.44 [T].

Similarly, when the first portion 231 and the second portion 232 are the same type of magnet, for example, the first portion 231 is a sintered ferrite magnet and the second portion 232 is also a sintered ferrite magnet. In this case, the residual magnetic flux density of the first portion 231, which is a sintered ferrite magnet, is 0.43 [T] to 0.45 [T], and the residual magnetic flux density of the second portion 232, which is a sintered ferrite magnet, is 0. 0.46 [T] to 0.47 [T].

If the first portion 231 is a rare earth magnet containing heavy rare earth elements such as dysprosium (Dy) and terbium (Tb), the second portion 232 may be a rare earth magnet containing no heavy rare earth elements. For example, the concentration of the heavy rare earth element in the first portion 231 is 4% by weight, and the concentration of the heavy rare earth element in the second portion 232 is 0% by weight. In this case, at least a part of the first portion 231 should contain the heavy rare earth element. In the permanent magnet 23, as the heavy rare earth element concentration increases, the coercive force increases and the residual magnetic flux density decreases.

Each permanent magnet 23 is magnetized in a direction perpendicular to the longitudinal direction of the permanent magnet 23 in the xy plane. That is, each permanent magnet 23 is magnetized in the lateral direction of the permanent magnet 23 in the xy plane. In one magnetic pole of the rotor 2 , a set of permanent magnets 23 (specifically, two permanent magnets 23 ) functions as an north pole or south pole with respect to the stator 3 . Therefore, in this embodiment, the rotor 2 has six poles. However, the number of magnetic poles of the rotor 2 should be two or more.

FIG. 6 is a perspective view schematically showing the structure of part of the stator 3. FIG.
In the example shown in FIG. 6, the stator core 30 has two first stator cores 31 and one second stator core 32, and one second stator core 32 is arranged between the two first stator cores 31. . For example, the length of one first stator core 31 in the axial direction is 7.5 mm, and the length of the second stator core 32 in the axial direction is 15 mm.

However, the number of first stator cores 31 and second stator cores 32 is not limited to the example shown in FIG. 6, and the arrangement of first stator cores 31 and second stator cores 32 is not limited to the example shown in FIG. For example, the first rotor core 21 and the first stator core 31 may be arranged between the second rotor core 22 and the second stator core 32, respectively. One first rotor core 21 and one second rotor core 22 may form the rotor core 20 , and one first stator core 31 and one second stator core 32 may form the stator core 30 . The first rotor cores 21 and the second rotor cores 22 may be alternately arranged, and similarly the first stator cores 31 and the second stator cores 32 may be alternately arranged.

As shown in FIG. 6, the stator core 30 includes a yoke 33 extending in the circumferential direction, a plurality of teeth 34 extending radially from the yoke 33, a plurality of slots 35, and at least one recess 36. have. In this embodiment, nine teeth 34 are arranged at regular intervals. That is, nine teeth 34 are radially positioned. A slot 35 is a space between teeth 34 adjacent to each other.

The first stator core 31 is an annular core. The first stator core 31 has a plurality of magnetic steel sheets 310 laminated in the axial direction. These electromagnetic steel plates 310 are fixed to each other by caulking. Each of the plurality of electromagnetic steel sheets 310 is punched into a predetermined shape. Each thickness of the plurality of electromagnetic steel sheets 310 is, for example, 0.1 mm or more and 0.7 mm or less. In this embodiment, the thickness of each of the plurality of electromagnetic steel sheets 310 is 0.35 mm.

The second stator core 32 is an annular core. The second stator core 32 has a plurality of magnetic steel sheets 320 laminated in the axial direction. These electromagnetic steel plates 320 are fixed to each other by caulking. Each of the plurality of electromagnetic steel sheets 320 is punched into a predetermined shape. Each thickness of the plurality of electromagnetic steel sheets 320 is, for example, 0.1 mm or more and 0.7 mm or less. In this embodiment, the thickness of each of the plurality of electromagnetic steel sheets 320 is 0.35 mm.

As described above, the first stator core 31 and the second stator core 32 have multiple teeth 34 . Furthermore, the first stator core 31 and the second stator core 32 have yokes 33 .

FIG. 7 is a plan view schematically showing the structure of part of the stator 3 shown in FIG. 1. FIG.
8 is a plan view schematically showing the structure of part of the stator 3 shown in FIG. 3. FIG.
Each tooth 34 protrudes from the yoke 33 toward the center of rotation of the rotor 2 . Each tooth 34 has a radially extending main body portion 34a and a circumferentially extending tooth distal end portion 34b positioned at the distal end of the main body portion 34a.

A stator winding 37 is wound around each tooth 34 so that each slot 35 is provided with a stator winding 37 . For example, the stator winding 37 is wound around each tooth 34 by concentrated winding. An insulator is preferably arranged between the stator winding 37 and each tooth 34 .

The stator windings 37 form coils that generate a rotating magnetic field. The coil is, for example, a three-phase coil, and the connection method is, for example, Y connection. The stator winding 37 is, for example, magnet wire with a diameter of 1 mm. When current flows through the stator windings 37, a rotating magnetic field is generated. The number of turns and the diameter of the stator winding 37 are set according to the voltage applied to the stator winding 37, the rotation speed of the electric motor 1, the cross-sectional area of the slot 35, and the like. The number of turns of the stator winding 37 is 80, for example.

In the xy plane, the boundary between the inner peripheral surface of the yoke 33 of the second stator core 32 and the side surface of the main body portion 34a of the tooth 34 of the second stator core 32 is formed in an arc shape. In the xy plane, the radius of curvature of the boundary between the inner peripheral surface of the yoke 33 of the second stator core 32 and the side surface of the main body portion 34a of the tooth 34 of the second stator core 32 is the inner peripheral surface of the yoke 33 of the first stator core 31. and the side surfaces of the main body portions 34 a of the teeth 34 of the first stator core 31 .

As shown in FIGS. 6 and 7, the width of the yoke 33 of the first stator core 31 in the radial direction (that is, the width in the y-axis direction in FIG. 7) is the width of the yoke 33 of the second stator core 32 (that is, the width in FIG. 8 is narrower than the width in the y-axis direction). As a result, recesses 36 are provided in stator core 30 . In other words, a gap is provided between the yoke 33 of the first stator core 31 and the stator windings 37 .

Furthermore, the width of the body portions 34a of the teeth 34 of the first stator core 31 in the direction orthogonal to the radial direction (that is, the width in the x-axis direction in FIG. 7) is the width of the body portions 34a of the teeth 34 of the second stator core 32. (that is, the width in the x-axis direction in FIG. 8). Furthermore, the width in the radial direction of the tooth tip portions 34 b of the first stator core 31 is narrower than the width of the tooth tip portions 34 b of the second stator core 32 . Accordingly, gaps are provided between the teeth 34 of the first stator core 31 and the stator windings 37 , and as a result, the recesses 36 are provided in the stator core 30 .

As described above, the width of the yoke 33 of the first stator core 31 is narrower than the width of the yoke 33 of the second stator core 32, and the width of the teeth 34 of the first stator core 31 is narrower than the width of the teeth 34 of the second stator core 32. is also narrow. Therefore, the area of the slots 35 in the first stator core 31 is larger than the area of the slots 35 in the second stator core 32 in the xy plane.

The recess 36 is provided at a position facing the slot 35 . As shown in FIGS. 6 and 7, recesses 36 do not contact stator windings 37 . In this case, the recesses 36 are the side surfaces of the yoke 33 of the first stator core 31 and also the side surfaces of the teeth 34 of the first stator core 31 .

If the first stator core 31 includes at least one electromagnetic steel sheet 310 having a width narrower than the width of the yoke 33 of the second stator core 32, the electromagnetic steel sheet has the same structure as the electromagnetic steel sheet 320 of the second stator core 32. may include Similarly, if the first stator core 31 includes at least one electromagnetic steel sheet 310 having a width narrower than the width of the body portion 34a of the tooth 34 of the second stator core 32, the structure of the electromagnetic steel sheet 320 of the second stator core 32 is may include an electromagnetic steel sheet having the same structure as Similarly, if the first stator core 31 includes at least one electromagnetic steel sheet 310 having a width narrower than the width of the tooth tip portions 34b of the second stator core 32, the structure of the electromagnetic steel sheet 320 is the same as that of the second stator core 32. An electromagnetic steel sheet having a structure may be included.

FIG. 9 is a diagram showing another structure of the first stator core 31 (specifically, the teeth 34 of the first stator core 31).
In the example shown in FIG. 9, a recess 36a is formed in the body portion 34a of the first stator core 31. In the example shown in FIG. Accordingly, gaps are provided between the teeth 34 of the first stator core 31 and the stator windings 37 , and as a result, the recesses 36 are provided in the stator core 30 . The size and shape of the depression 36a are not limited to the example shown in FIG.

Advantages of the electric motor 1 according to the first embodiment will be described.
In the present embodiment, the width of the yoke 33 of the first stator core 31 in the radial direction is narrower than the width of the yoke 33 of the second stator core 32 . In other words, stator 3 has at least one recess 36 . Accordingly, the distance from rotor core 20 to first stator core 31 is longer than the distance from rotor core 20 to second stator core 32 . As a result, the capacitance of the stator core 30 (especially the first stator core 31) can be reduced, and the reliability of the electric motor 1 can be enhanced.

Furthermore, in the example shown in FIGS. 1 and 6 , since a gap is provided between the yoke 33 of the first stator core 31 and the stator winding 37 , from the stator winding 37 to the yoke 33 of the first stator core 31 . current leakage can be reduced. Furthermore, since the gap is provided between the teeth 34 of the first stator core 31 and the stator windings 37, leakage of current from the stator windings 37 to the teeth 34 of the first stator core 31 can be reduced.

On the other hand, the stator 3 , more specifically, the stator core 30 is provided with the recess 36 , so the area of the first rotor core 21 in the xy plane is smaller than the area of the second stator core 32 . As a result, magnetic saturation tends to occur in first stator core 31 , and iron loss tends to increase in first stator core 31 . As a result, motor efficiency may decrease.

Even in such a case, in electric motor 1 according to the present embodiment, the residual magnetic flux density of first portion 231 of permanent magnet 23 is lower than the residual magnetic flux density of second portion 232 of permanent magnet 23 . As a result, the amount of magnetic flux flowing from the first rotor core 21 to the first stator core 31 is reduced, magnetic saturation in the first stator core 31 can be alleviated, and iron loss is reduced.

As described above, according to the electric motor 1 according to the present embodiment, the electrostatic capacity of the stator core 30 can be reduced, magnetic saturation in the first stator core 31 can be alleviated, and iron loss can be reduced. . As a result, the reliability and efficiency of the electric motor 1 can be enhanced.

In each permanent magnet 23 , when the first portion 231 and the second portion 232 are magnets of different types, the amount of magnetic flux flowing from the first rotor core 21 to the second stator core 32 from the second rotor core 22 is greater than the amount of magnetic flux flowing from the second rotor core 22 to the second stator core 32 . The amount of magnetic flux flowing into one stator core 31 can be effectively reduced. As a result, the reliability and efficiency of the electric motor 1 can be effectively improved.

However, in each permanent magnet 23, even if the first portion 231 and the second portion 232 are the same type of magnet, the residual magnetic flux density of the first portion 231 is higher than the residual magnetic flux density of the second portion 232 of the permanent magnet 23. low. For example, when the first portion 231 is a neodymium sintered magnet and the second portion 232 is also a neodymium sintered magnet, the residual magnetic flux density of the first portion 231 is, for example, 1.2 [T], and the second The residual magnetic flux density of the portion 232 is 1.4 [T]. As a result, the amount of magnetic flux flowing from the first rotor core 21 to the first stator core 31 is reduced, magnetic saturation in the first stator core 31 can be alleviated, and iron loss is reduced.

When each permanent magnet 23 is a rare earth magnet, the concentration of heavy rare earth elements such as dysprosium (Dy) and terbium (Tb) in at least a portion of the first portion 231 is higher than the concentration of rare earth elements. In other words, if each permanent magnet 23 is a rare earth magnet, the first portion 231 includes a region with a higher heavy rare earth element concentration than the heavy rare earth element concentration in the second portion 232 . Thereby, in each permanent magnet 23 , the residual magnetic flux density of the first portion 231 is lower than the residual magnetic flux density of the second portion 232 . As a result, the amount of magnetic flux flowing from the first rotor core 21 to the first stator core 31 is reduced, magnetic saturation in the first stator core 31 can be alleviated, and iron loss is reduced.

However, if the first portion 231 is a rare earth magnet containing heavy rare earth elements such as dysprosium (Dy) and terbium (Tb), the second portion 232 may be a rare earth magnet containing no heavy rare earth elements. Thereby, in each permanent magnet 23 , the residual magnetic flux density of the first portion 231 is lower than the residual magnetic flux density of the second portion 232 . As a result, the amount of magnetic flux flowing from the first rotor core 21 to the first stator core 31 is reduced, magnetic saturation in the first stator core 31 can be alleviated, and iron loss is reduced.

Although each permanent magnet 23 is divided into the first portion 231 and the second portion 232 in the present embodiment, each permanent magnet 23 may be divided into the first portion 231 and the second portion 232. good. That is, even when the first portion 231 and the second portion 232 are integrated with each other, the electric motor 1 can obtain the above advantages.

For example, in each permanent magnet 23 that is a rare earth magnet, even if the first portion 231 and the second portion 232 are integrated with each other, dysprosium (Dy) in at least a partial region of the first portion 231 , and terbium (Tb) are higher than the concentration of heavy rare earth elements in the second portion 232 . In other words, if each permanent magnet 23 is a rare earth magnet, the first portion 231 includes a region with a higher heavy rare earth element concentration than the heavy rare earth element concentration in the second portion 232 . For example, in each permanent magnet 23, which is a neodymium sintered magnet, the concentration of the heavy rare earth element in at least a portion of the first portion 231 is 4% by weight, and the concentration of the heavy rare earth element in the second portion 232 is 4% by weight. 1% by weight. Thereby, in each permanent magnet 23 , the residual magnetic flux density of the first portion 231 is lower than the residual magnetic flux density of the second portion 232 . As a result, the amount of magnetic flux flowing from the first rotor core 21 to the first stator core 31 is reduced, magnetic saturation in the first stator core 31 can be alleviated, and iron loss is reduced.

Similarly, even when the first portion 231 and the second portion 232 of each permanent magnet 23, which is a rare earth magnet, are integrated with each other, the first portion 231 contains dysprosium (Dy), terbium (Tb), or the like. , the second portion 232 may be a rare earth magnet that does not contain heavy rare earth elements. For example, in each permanent magnet 23, which is a neodymium sintered magnet, the concentration of heavy rare earth elements in the first portion 231 is 4% by weight and the concentration of heavy rare earth elements in the second portion 232 is 0% by weight. Thereby, in each permanent magnet 23 , the residual magnetic flux density of the first portion 231 is lower than the residual magnetic flux density of the second portion 232 . As a result, the amount of magnetic flux flowing from the first rotor core 21 to the first stator core 31 is reduced, magnetic saturation in the first stator core 31 can be alleviated, and iron loss is reduced.

Embodiment 2.
A compressor 6 according to Embodiment 2 of the present invention will be described.
FIG. 10 is a cross-sectional view schematically showing the structure of compressor 6 according to Embodiment 2. As shown in FIG.

The compressor 6 has an electric motor 1 as an electric element, a sealed container 61 as a housing, and a compression mechanism 62 as a compression element (also referred to as a compression device). In this embodiment, the compressor 6 is a rotary compressor. However, the compressor 6 is not limited to a rotary compressor.

The electric motor 1 is the electric motor 1 described in the first embodiment. Electric motor 1 drives compression mechanism 62 .

The closed container 61 covers the electric motor 1 and the compression mechanism 62 . Refrigerating machine oil that lubricates sliding portions of the compression mechanism 62 is stored in the bottom portion of the sealed container 61 .

The compressor 6 further has a glass terminal 63 fixed to the closed container 61 , an accumulator 64 , a suction pipe 65 and a discharge pipe 66 .

The compression mechanism 62 includes a cylinder 62a, a piston 62b, an upper frame 62c (first frame), a lower frame 62d (second frame), and a plurality of mufflers attached to the upper frame 62c and the lower frame 62d, respectively. 62e. The compression mechanism 62 further has a vane that divides the inside of the cylinder 62a into a suction side and a compression side. The compression mechanism 62 is arranged inside the closed container 61 . Compression mechanism 62 is driven by electric motor 1 .

The stator 3 of the electric motor 1 is fixed within the closed container 61 by one of press fitting and shrink fitting. The stator 3 may be attached directly to the sealed container 61 by welding instead of press fitting and shrink fitting.

Electric power is supplied to the coils (that is, the stator windings 37 ) of the electric motor 1 through the glass terminals 63 .

The rotor of the electric motor 1 (specifically, the shaft 26 of the rotor 2) is rotatably held by the upper frame 62c and the lower frame 62d via bearings provided on the upper frame 62c and the lower frame 62d. there is

The shaft 26 is inserted into the piston 62b. A shaft 26 is rotatably inserted into the upper frame 62c and the lower frame 62d. The upper frame 62c and the lower frame 62d close the end face of the cylinder 62a. The accumulator 64 supplies refrigerant (for example, refrigerant gas) to the cylinder 62a through a suction pipe 65. As shown in FIG.

Next, operation of the compressor 6 will be described. Refrigerant supplied from the accumulator 64 is sucked into the cylinder 62 a through a suction pipe 65 fixed to the closed container 61 . By driving the electric motor 1, the piston 62b fitted to the shaft 26 rotates within the cylinder 62a. As a result, the refrigerant is compressed within the cylinder 62a.

The refrigerant rises inside the sealed container 61 through the muffler 62e. Refrigerant oil is mixed in the compressed refrigerant. When the mixture of the refrigerant and the refrigerating machine oil passes through the hole formed in the rotor core of the electric motor 1, the separation of the refrigerant and the refrigerating machine oil is promoted, thereby preventing the refrigerating machine oil from flowing into the discharge pipe 66. can. Compressed refrigerant is thus supplied through the discharge pipe 66 to the high pressure side of the refrigeration cycle.

As a refrigerant for the compressor 6, R410A, R407C, R22, or the like can be used. However, the refrigerant for the compressor 6 is not limited to these. For example, a low GWP (global warming potential) refrigerant or the like can be used as the refrigerant for the compressor 6 .

Representative examples of low GWP refrigerants include the following refrigerants.

(1) A halogenated hydrocarbon having carbon double bonds in its composition is, for example, HFO-1234yf (CF3CF=CH2). HFO is an abbreviation for Hydro-Fluoro-Olefin. Olefin means an unsaturated hydrocarbon with one double bond. The GWP of HFO-1234yf is 4.

(2) A hydrocarbon having carbon double bonds in its composition is, for example, R1270 (propylene). The GWP of R1270 is 3, which is lower than that of HFO-1234yf, but the flammability of R1270 is better than that of HFO-1234yf.

(3) A mixture containing at least one of a halogenated hydrocarbon having a carbon double bond in its composition and a hydrocarbon having a carbon double bond in its composition is, for example, a mixture of HFO-1234yf and R32. be. Since HFO-1234yf is a low-pressure refrigerant, the pressure loss increases, and the performance of the refrigeration cycle tends to deteriorate, especially in the evaporator. Therefore, it is desirable to use a mixture with high-pressure refrigerants such as R32 or R41.

The compressor 6 according to the second embodiment has the advantages described in the first embodiment.

Furthermore, since the compressor 6 according to Embodiment 2 has the electric motor 1, it is possible to provide the compressor 6 with high compression efficiency.

Embodiment 3.
A refrigerating and air-conditioning apparatus 7 as an air conditioner having a compressor 6 according to Embodiment 2 will be described.
FIG. 11 is a diagram schematically showing the configuration of a refrigerating and air-conditioning device 7 according to Embodiment 3 of the present invention.

The refrigerating and air-conditioning device 7 is capable of cooling and heating operation, for example. The refrigerant circuit diagram shown in FIG. 11 is an example of a refrigerant circuit diagram of an air conditioner capable of cooling operation.

A refrigerating and air-conditioning apparatus 7 according to Embodiment 3 has an outdoor unit 71 , an indoor unit 72 , and a refrigerant pipe 73 connecting the outdoor unit 71 and the indoor unit 72 .

The outdoor unit 71 has a compressor 6, a condenser 74 as a heat exchanger, an expansion device 75, and an outdoor fan 76 (first fan). The condenser 74 condenses the refrigerant compressed by the compressor 6 . The expansion device 75 reduces the pressure of the refrigerant condensed by the condenser 74 and adjusts the flow rate of the refrigerant. The throttle device 75 is also called a decompression device.

The indoor unit 72 has an evaporator 77 as a heat exchanger and an indoor fan 78 (second fan). The evaporator 77 evaporates the refrigerant decompressed by the expansion device 75 to cool the indoor air.

The basic operation of the cooling operation of the refrigerating and air-conditioning device 7 will be described below. In cooling operation, refrigerant is compressed by compressor 6 and flows into condenser 74 . The refrigerant is condensed by the condenser 74 and the condensed refrigerant flows into the expansion device 75 . The refrigerant is depressurized by the throttle device 75 and the depressurized refrigerant flows into the evaporator 77 . The refrigerant evaporates in the evaporator 77 and the refrigerant (specifically, refrigerant gas) flows into the compressor 6 of the outdoor unit 71 again. When air is sent to the condenser 74 by the outdoor blower 76, heat is transferred between the refrigerant and the air. Similarly, when air is sent to the evaporator 77 by the indoor blower 78, heat is transferred between the refrigerant and the air. Moving.

The configuration and operation of the refrigerating and air-conditioning device 7 described above are examples, and are not limited to the above-described example.

The refrigerating and air-conditioning apparatus 7 according to the third embodiment has the advantages described in the first and second embodiments.

Furthermore, since the refrigerating and air-conditioning apparatus 7 according to Embodiment 3 has the compressor 6 with high compression efficiency, it is possible to provide the refrigerating and air-conditioning apparatus 7 with high efficiency.

As described above, preferred embodiments have been specifically described, but it is obvious that a person skilled in the art can adopt various modifications based on the basic technical idea and teaching of the present invention. .

The features of the embodiments described above can be combined as appropriate.

REFERENCE SIGNS LIST 1 electric motor 2 rotor 3 stator 6 compressor 7 refrigerating and air-conditioning device 20 rotor core 21 first rotor core 22 second rotor core 23 permanent magnet 30 stator core 31 first stator core 32 second stator core 35 slot , 36 recessed portion, 61 sealed container, 62 compression mechanism, 74 condenser, 75 throttle device, 77 evaporator, 211 first hole, 212 first magnet placement portion, 213 first flux barrier portion, 221 second hole, 222 second 2 magnet arrangement part, 223 second flux barrier part, 231 first part, 232 second part.

Claims (10)

a stator having axially laminated first and second stator cores and slots in which stator windings are arranged;
a first rotor core radially facing the first stator core, a second rotor core radially facing the second stator core, and at least one permanent magnet having a first portion and a second portion; a rotor disposed inside the stator;
the stator has recesses facing the slots that do not contact the stator windings;
The first rotor core has at least one first hole having a first magnet arrangement portion in which the first portion is arranged and a first flux barrier portion communicating with the first magnet arrangement portion,
The second rotor core has at least one second hole having a second magnet arrangement portion in which the second portion is arranged and a second flux barrier portion communicating with the second magnet arrangement portion,
The electric motor, wherein the residual magnetic flux density of the first portion is lower than the residual magnetic flux density of the second portion. a stator having axially laminated first and second stator cores and slots in which stator windings are arranged;
a first rotor core radially facing the first stator core, a second rotor core radially facing the second stator core, and at least one permanent magnet having a first portion and a second portion; a rotor disposed inside the stator;
with
the stator has recesses facing the slots that do not contact the stator windings;
the first rotor core has at least one first hole having a first magnet arrangement portion in which the first portion is arranged;
the second rotor core has at least one second hole having a second magnet arrangement portion in which the second portion is arranged;
The residual magnetic flux density of the first portion is lower than the residual magnetic flux density of the second portion
Electric motor. the at least one permanent magnet is divided into the first portion and the second portion;
3. The electric motor according to claim 1, wherein the first portion and the second portion are different types of magnets. the at least one permanent magnet is divided into the first portion and the second portion;
3. A motor according to claim 1 or 2 , wherein the first part and the second part are magnets of the same kind. the at least one permanent magnet is a rare earth magnet;
the at least one permanent magnet is divided into the first portion and the second portion;
The electric motor according to claim 1 or 2 , wherein the concentration of the heavy rare earth element in at least a part of the first portion is higher than the concentration of the heavy rare earth element in the second portion. the at least one permanent magnet is divided into the first portion and the second portion;
the first part is a rare earth magnet containing a heavy rare earth element;
The electric motor according to claim 1 or 2 , wherein the second portion is a rare earth magnet containing no heavy rare earth element. the at least one permanent magnet is a rare earth magnet;
the first portion and the second portion are integrated with each other;
The electric motor according to claim 1 or 2 , wherein the concentration of the heavy rare earth element in at least a part of the first portion is higher than the concentration of the heavy rare earth element in the second portion. the first portion and the second portion are integrated with each other;
the first part is a rare earth magnet containing a heavy rare earth element;
The electric motor according to claim 1 or 2 , wherein the second portion is a rare earth magnet containing no heavy rare earth element. a closed container;
a compression device disposed within the closed vessel;
and the electric motor according to any one of claims 1 to 8 , for driving the compression device. a compressor according to claim 9 ;
An air conditioner comprising a heat exchanger and

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