JP6133350B2 - Permanent magnet motor and compressor - Google Patents

Description

  The present invention relates to a permanent magnet motor and a compressor including the permanent magnet motor.

A permanent magnet motor is used as an electric motor for driving a compressor, a vehicle, an in-vehicle device mounted on the vehicle, and the like provided in a refrigerator or an air conditioner. For example, a stator and a rotor are provided, and the rotor has a main magnetic pole and an auxiliary magnetic pole arranged alternately along the circumferential direction when viewed in a cross section perpendicular to the axial direction, and a magnet is inserted into the main magnetic pole. A permanent magnet electric motor (referred to as a “permanent magnet embedded electric motor”) in which a permanent magnet is inserted is used in the magnet insertion hole. Such a permanent magnet motor can utilize both magnet torque due to the magnetic flux of the permanent magnet and reluctance torque due to the saliency of the rotor.
As the permanent magnet, a high-performance rare earth magnet having a higher residual magnetic flux density than a ferrite magnet is used. As the rare earth magnet, a neodymium magnet containing neodymium (Nd) and iron (Fe) is typically known. Such neodymium magnets are required to have an improved holding force because the holding force decreases as the ambient temperature increases. Conventionally, as a technique for increasing the holding power of such a neodymium magnet, there is a technique for diffusing dysprosium (Dy) or terbium (Tb) along the crystal-crystal interface (grain boundary) from the outer peripheral surface of the neodymium magnet. Known (Patent Documents 1 and 2).
Patent Document 3 discloses a permanent magnet motor using a neodymium magnet containing dysprosium (Dy) or terbium (Tb).

JP 2008-263179 A JP 2009-289994 A JP 2014-147151 A

A neodymium magnet containing terbium can improve magnetic properties such as residual magnetic flux density and coercive force than a neodymium magnet containing dysprosium. For this reason, the use of a neodymium magnet containing terbium is desired. However, terbium is more expensive than dysprosium.
The present invention was devised in view of these points, and is a novel technique that can improve the efficiency of a permanent magnet motor using a neodymium magnet containing terbium while suppressing the amount of terbium used. The purpose is to provide.

1st-4th invention is related with the permanent magnet motor which drives the compression mechanism part of a compressor.
The first to permanent magnet motor of the fourth invention includes a stator, comprising a rotor having a permanent magnet, a clearance (air gap) between the outer surface and the inner peripheral surface of the stator of the rotor , rotor, as viewed in the axial direction in cross section perpendicular has a main pole and an auxiliary pole are arranged alternately along the circumferential direction, the magnet insertion holes are formed in the main pole, the magnet insertion holes Has a permanent magnet inserted. The shape and number of magnet insertion holes and the shape and number of permanent magnets inserted into the magnet insertion holes are appropriately selected. As the permanent magnet, a neodymium magnet containing neodymium, iron and terbium is used. The neodymium magnet may contain materials other than neodymium, iron, and terbium. Further, the gap along the d-axis of the main magnetic pole is configured to be smaller than the gap along the q-axis of the auxiliary magnetic pole.
In the permanent magnet motor of the first invention , the rotor has a four-pole structure with four main magnetic poles, and the terbium content is set in the range of 0.5 wt% and 2 wt%. Neodymium magnets are used.
In the permanent magnet motor of the second invention , the rotor has a six-pole structure with six main magnetic poles, and the terbium content is set within a range of 0.4 wt% and 2 wt%. Neodymium magnets are used.
In the permanent magnet motor of the third invention , the rotor has an 8-pole structure with 8 main magnetic poles, and the terbium content is set within the range of 0.3 wt% and 2 wt%. Neodymium magnets are used.
In the permanent magnet motor of the fourth invention , the rotor has a 10-pole structure in which the number of main magnetic poles is 10, and the terbium content is set within the range of 0.2 wt% and 2 wt%. Neodymium magnets are used.
In the permanent magnet motors of the first to fourth inventions, the efficiency can be improved while suppressing the amount of terbium used.
Since the magnetic flux from the stator to the rotor and the magnetic flux from the rotor to the stator flows through the auxiliary magnetic pole, the magnetic flux density of the auxiliary magnetic pole is very high compared to the magnetic flux density of the main magnetic pole. For this reason, the permanent magnet is demagnetized by the magnetic flux flowing through the auxiliary magnetic pole.
In the first to fourth inventions, the gap along the d-axis of the main magnetic pole is smaller than the gap along the q-axis of the auxiliary magnetic pole. Since it is set to be larger than the gap along the line, the amount of magnetic flux flowing through the auxiliary magnetic pole can be reduced, and demagnetization of the permanent magnet due to the magnetic flux flowing through the auxiliary magnetic pole can be suppressed. This makes it possible to use a neodymium magnet having a small terbium content compared to a rotor having a circular cross section with the same distance from the shaft center to the outer peripheral surface of the rotor.
In the different forms of the first to fourth inventions, the neodymium magnet further includes praseodymium (Pr).
The raw material (ore) of neodymium includes other metals such as praseodymium in addition to the metals such as neodymium and iron that make up the neodymium magnet. Praseodymium is usually separated from the metal that makes up the neodymium magnet. Yes. In this embodiment, since a neodymium magnet containing neodymium, praseodymium, iron, and terbium is used, a step of separating praseodymium is not required, and a permanent magnet motor having desired characteristics can be provided while reducing costs .
In another different form of the first to fourth inventions, the outer peripheral surface of the rotor is a first portion that intersects the d-axis of the main magnetic pole as viewed in a cross section orthogonal to the axial direction, and the q-axis of the auxiliary magnetic pole. The length of the second portion from the axial center along the q-axis is smaller than the length of the first portion from the axial center along the d-axis. Is formed.
The first portion and the second portion are formed in a curved shape, typically an arc shape with different curvature radii.
In this embodiment, the gap along the d-axis of the main magnetic pole can be simply configured to be smaller than the gap along the q-axis of the auxiliary magnetic pole.
The fifth invention relates to a compressor.
The present invention includes a compression mechanism section that compresses a working medium (generally called “refrigerant”) that moves thermal energy, and an electric motor that drives the compression mechanism section. Any of the above-described permanent magnet motors is used as the motor.
The present invention has the same effect as each permanent magnet motor described above.

  By using the permanent magnet motor and the compressor of the present invention, the efficiency can be improved while suppressing the amount of terbium used.

It is a figure which shows schematic structure of one Embodiment of the compressor of this invention. It is a figure showing the schematic structure of a 1st embodiment of the permanent magnet motor of the present invention. It is a figure which shows schematic structure of 2nd Embodiment of the permanent magnet electric motor of this invention. It is a figure which shows schematic structure of 3rd Embodiment of the permanent magnet electric motor of this invention. It is a figure which shows schematic structure of 4th Embodiment of the permanent magnet electric motor of this invention. It is a figure which shows schematic structure of 5th Embodiment of the permanent magnet electric motor of this invention. It is a figure which shows schematic structure of 6th Embodiment of the permanent magnet electric motor of this invention. It is a figure which shows schematic structure of 7th Embodiment of the permanent magnet electric motor of this invention. It is a graph which shows the relationship between the terbium (Tb) content in the neodymium magnet containing terbium (Tb), the demagnetization start current, and the number of poles of the main pole of the rotor. It is a graph which shows the relationship between terbium (Tb) content and residual magnetic flux density in the neodymium magnet containing terbium (Tb).

Embodiments of the present invention will be described below with reference to the drawings.
In the present specification, the description “axial center” indicates the rotational center of the rotor (rotating shaft) in a state where the rotor is rotatably arranged with respect to the stator. The description “axial direction” indicates the extending direction of the rotation center line passing through the axis center in a state where the rotor is rotatably arranged with respect to the stator. The description “circumferential direction” indicates a circumferential direction centered on the axis center when viewed from a direction orthogonal to the axial direction in a state where the rotor is rotatably arranged with respect to the stator. The description “radial direction” indicates a direction passing through the center of the shaft when viewed from a direction orthogonal to the axial direction in a state where the rotor is rotatably arranged with respect to the stator.

One embodiment of the compressor of the present invention is shown in FIGS. FIG. 1 is a cross-sectional view illustrating a schematic configuration of a compressor 10 according to an embodiment, and FIG. 2 is a view taken along line II-II in FIG. FIG. 2 shows a schematic configuration of the first embodiment 100 of the permanent magnet motor of the present invention.
The compressor 10 of this embodiment is configured as a rotary type compressor in which a rotary type compression mechanism is disposed in a sealed container.
The compressor 10 includes a sealed container 20, a compression mechanism unit 30 accommodated in the sealed container 20, a permanent magnet electric motor 100, an accumulator 40, and the like. In the present embodiment, the permanent magnet motor 100 is disposed above the compression mechanism unit 30 along the vertical direction.
In the sealed container 20, a suction port 22 is provided below the permanent magnet motor 100, and a discharge port 21 is provided above the permanent magnet motor 100. In addition, an oil sump 36 in which lubricating oil supplied to the bearing portions 34 and 35 of the rotating shaft 130 and the sliding portion of the compression mechanism portion 30 is stored at the bottom of the sealed container 20 (below the compression mechanism portion 30). Is provided.
The sealed container 20 corresponds to the “container” of the present invention.

The compression mechanism unit 30 compresses a working medium (generally called “refrigerant”) that moves thermal energy. As the working medium, an HFC (hydrofluorocarbon) refrigerant having an ozone depletion potential (ODP) of zero, for example, HFC-R410a is used. In recent years, HFC-R32 having a global warming potential (GWP) smaller than HFC-R410a (about 1/3) has been used.
The compression mechanism unit 30 includes a cylinder 31, an eccentric rotor 32 that is rotated by a rotation shaft 130, and a compression chamber 33. The rotating shaft 130 is rotatably supported by the bearing portions 34 and 35. When the eccentric rotor 32 of the compression mechanism unit 30 is rotated by the rotation of the rotating shaft 130, the working medium sucked from the suction port 22 is compressed in the compression chamber 33.
Note that the lubricating oil stored in the oil sump 36 is supplied to the bearing portions 34 and 35, the sliding portion of the compression mechanism portion 30, and the like by the rotation of the rotating shaft 130. The lubricating oil that has lubricated the bearing portions 34 and 35 and the sliding portion is returned to the oil sump 36.

The permanent magnet motor 100 includes a stator 110 and a rotor 120 that is rotatably supported with respect to the stator 110.
Stator 110 is constituted by a stator core formed by laminating a plurality of plate-shaped electromagnetic steel plates. As shown in FIG. 2, the stator 110 (stator core) includes a yoke 111 extending along the circumferential direction and a radial direction from the yoke 111 when viewed in a cross section perpendicular to the axial direction. It has the teeth 112 extended to the axial center P side. The teeth 112 are formed by a teeth base 113 extending along the radial direction, and a tooth tip 114 extending in the circumferential direction and connected to the axial center P side of the teeth base 113. A tooth front end surface 114 a is formed on the axis center P side of the tooth front end portion 114. Teeth front end surface 114 a corresponds to the inner peripheral surface of stator 110. In the present embodiment, the tooth front end surface 114a has an arc shape centered on the axis center.
A slot 115 is formed by teeth 112 adjacent in the circumferential direction, and a stator winding 116 is disposed in the slot 115.
In the permanent magnet motor 100 of this embodiment, six teeth 112 (slots 115) are provided, and the stator winding 116 is wound around the teeth 112 by a concentrated winding method.
The stator 110 is tightly fitted inside the sealed container 20 by press fitting, shrink fitting, or the like. The inner peripheral shape of the sealed container 20 and the outer peripheral shape of the stator core 110 are formed into appropriate shapes including a circular shape.

The rotor 120 is constituted by a rotor core formed by laminating a plurality of plate-shaped electromagnetic steel plates. End plates 123 and balance weights 124 are disposed at both axial ends of the rotor core. The rotor core, the end plate 123 and the balance weight 124 are integrated by the caulking pin 125 inserted into the caulking pin insertion hole. The rotor 120 (rotor core) has a rotating shaft 130 inserted into the rotating shaft insertion hole, and is arranged rotatably on the inner peripheral side of the stator 110. In the present embodiment, the outer peripheral surface 120a of the rotor 120 (rotor core) has a circular shape with the axis center P as the center. And it arrange | positions so that the space | gap (air gap) G may be hold | maintained between the internal peripheral surface (teeth front end surface 114a) of the stator 110, and the outer peripheral surface 120a of the rotor 120. FIG.
The rotor 120 (rotor core) has main magnetic poles and auxiliary magnetic poles arranged alternately along the circumferential direction when viewed in a cross section perpendicular to the axial direction. In the present embodiment, the number of main magnetic poles of the rotor 120 is set to four. That is, the rotor 120 has a quadrupole structure (4P).
A magnet insertion hole 121 is formed in each main magnetic pole, and a permanent magnet 122 is inserted into the magnet insertion hole 121. In the present embodiment, the magnet insertion hole 121 is linear in a direction orthogonal (including “substantially orthogonal”) to the d-axis of the main magnetic pole (a line connecting the axial center P and the circumferential center of the outer peripheral surface of the main magnetic pole). It is formed to extend. A permanent magnet 122 having a quadrangular cross-sectional shape perpendicular to the axial direction is inserted into the magnet insertion hole 121. Preferably, a positioning portion for defining the position of the permanent magnet 122 in the magnet insertion hole 121 is provided. For example, a positioning part is formed on at least one of an inner peripheral wall and an outer peripheral wall forming the magnet insertion hole 121 so as to protrude inward.
In the present embodiment, a neodymium magnet containing neodymium (Nd), iron (Fe), and terbium (Tb) is used as the permanent magnet 122. As the neodymium magnet containing neodymium, iron and terbium, for example, the neodymium magnet disclosed in Patent Documents 1 to 3 can be used.

The compressor 10 of this embodiment operates as follows.
Although not shown, the permanent magnet motor 100 is provided with a passage that communicates the compression mechanism 30 side and the discharge port 21 side. For example, a passage communicating with the stator 110 and the rotor 120 in the axial direction is formed between the outer peripheral surface of the stator 110 and the inner peripheral surface of the sealed container 20, and the outer peripheral surface 120a of the rotor 120 A gap between the inner peripheral surface of the stator 110 (tooth tip surface 114a) is used as a passage.
When a magnetic field is generated from the stator winding 116 by supplying current to the stator winding 116 and the rotor 120 (rotary shaft 130) rotates, the rotor 120 (rotating shaft 130) rotates and is sucked from the accumulator 40 through the suction pipe 41 and the suction port 22. The working medium is compressed by the compression mechanism 30.
The working medium compressed by the compression mechanism unit 30 flows through the passage of the permanent magnet motor 100 from the lower side (compression mechanism unit 30 side) to the upper side (opposite side of the compression mechanism unit 30) of the permanent magnet motor 100, and the discharge port. 21 is discharged.

In the permanent magnet motor 100 of the first embodiment, the rotor 120 having a four-pole structure is used. However, the number of main magnetic poles (number of poles) of the rotor is set to the number of main magnetic poles of the permanent magnet motor 100 of the first embodiment. A permanent magnet motor 200 of the second embodiment set to a value different from the number will be described with reference to FIG. In other embodiments described below, the configuration of the compressor 10 is the same as that of the embodiment of FIG. 1, and therefore only the configuration of the permanent magnet motor will be described.
The permanent magnet motor 200 of the second embodiment shown in FIG. 3 includes a stator 210 and a rotor 220.
In the present embodiment, the stator 210 is provided with nine teeth 212 (slots 215), and the stator winding is wound around the teeth 212 by a concentrated winding method.
The number of main magnetic poles of the rotor 220 is set to 6. That is, the rotor 220 has a hexapole structure (6P). The magnet insertion hole 221 of each main magnetic pole is formed so as to extend linearly in a direction orthogonal (including “substantially orthogonal”) to the d-axis of the main magnetic pole. A permanent magnet 222 having a quadrangular cross-sectional shape perpendicular to the axial direction is inserted into the magnet insertion hole 221.

The permanent magnet motor 300 of the third embodiment in which the number of main magnetic poles (number of poles) of the rotor is set to a value different from the number of main magnetic poles (number of poles) of the rotor of the first and second embodiments. This will be described with reference to FIG.
A permanent magnet motor 300 according to the third embodiment shown in FIG. 4 includes a stator 310 and a rotor 320.
In the present embodiment, the stator 310 is provided with twelve teeth 312 (slots 315), and the stator winding is wound around the teeth 312 by a concentrated winding method.
Further, the number of main magnetic poles of the rotor 320 is set to eight. That is, the rotor 320 has an octupole structure (8P). The magnet insertion hole 321 of each main magnetic pole is formed so as to extend linearly in a direction orthogonal (including “substantially orthogonal”) to the d-axis of the main magnetic pole. A permanent magnet 322 having a quadrangular cross-sectional shape perpendicular to the axial direction is inserted into the magnet insertion hole 321.

The permanent magnet motor 400 of the fourth embodiment in which the number of main poles (number of poles) of the rotor is set to a value different from the number of poles (number of poles) of the rotor of the first to third embodiments. This will be described with reference to FIG.
A permanent magnet motor 400 of the fourth embodiment shown in FIG. 5 includes a stator 410 and a rotor 420.
In the present embodiment, the stator 410 is provided with 15 teeth 412 (slots 415), and the stator winding is wound around the teeth 412 by a concentrated winding method.
The number of main magnetic poles of the rotor 420 is set to 10. That is, the rotor 420 has a 10-pole structure (10P). The magnet insertion hole 421 of each main magnetic pole is formed so as to extend linearly in a direction orthogonal (including “substantially orthogonal”) to the d-axis of the main magnetic pole. A permanent magnet 422 having a quadrangular cross-sectional shape perpendicular to the axial direction is inserted into the magnet insertion hole 421.

Next, the number of poles of the main magnetic pole of the rotor of the permanent magnet motor is 4 (4 poles: 4P), 6 (6 poles: 6P), 8 (8 poles: 8P), 10 (10 poles: 10P). FIG. 9 shows the relationship between the content of terbium (Tb) in the neodymium magnet and the demagnetization start current. In FIG. 9, the horizontal axis represents the terbium (Tb) content (wt%: wt%), and the vertical axis represents the demagnetization start current (A). The solid line indicates a graph when the number of poles of the main pole of the rotor is 4 (4P), the broken line indicates a graph when the number of poles of the main pole of the rotor is 6 (6P), and the alternate long and short dash line indicates the rotation. A graph when the number of poles of the main magnetic pole of the child is 8 (8P) is shown, and a two-dot chain line shows a graph when the number of poles of the main magnetic pole of the rotor is 10 (10P).
The demagnetization start current is a current at which demagnetization of the permanent magnet is started, and represents that the demagnetization is easier as the demagnetization start current is smaller.
From FIG. 9, in the region where the terbium (Tb) content is high, the demagnetization start current does not change greatly even if the content increases or decreases, but in the region where the terbium (Tb) content is low, the content decreases. It can be understood that the demagnetization start current becomes smaller according to the above.
Furthermore, it can be understood that the region where the demagnetization start current decreases as the terbium content decreases depends on the number of poles of the main pole of the rotor. That is, when the number of poles of the main pole is 4 (4P), the content is less than 0.5 wt%. When the number of poles of the main pole is 6 (6 P), the content is less than 0.4 wt%. In a small region, when the number of poles of the main pole is 8 (8P), the content is less than 0.3 wt%. When the number of poles of the main pole is 10 (10P), the content is 0.2 wt%. It can be understood that the demagnetization start current becomes smaller as the content decreases in a region smaller than%.
Therefore, in order to prevent demagnetization, that is, to prevent the demagnetization start current from becoming small, when the number of main poles of the rotor is 4 (4P), terbium (Tb) It is preferable to use a neodymium magnet having a content of 0.5 wt% or more. When the number of main poles of the rotor is 6 (6P), the content of terbium (Tb) is 0.4 wt% or more. It is preferable to use a neodymium magnet, and when the number of poles of the main magnetic pole of the rotor is 8 (8P), it is preferable to use a neodymium magnet having a terbium (Tb) content of 0.3 wt% or more. When the number of poles of the main magnetic pole of the rotor is 10 (10P), it can be understood that it is preferable to use a neodymium magnet having a terbium (Tb) content of 0.2 wt% or more.

Next, the relationship between the content of terbium (Tb) in the neodymium magnet and the residual magnetic flux density is shown in FIG. In FIG. 10, the horizontal axis indicates the terbium (Tb) content (wt%: wt%), and the vertical axis indicates the residual magnetic flux density (T).
From FIG. 10, it can be understood that the residual magnetic flux density decreases as the content of terbium (Tb) increases. In particular, in the region where the content of terbium is higher than 2.0 wt%, the content of terbium is increased. It can be understood that the rate of decrease in residual magnetic flux density with respect to the increase is small.
Therefore, it can be understood that by using a neodymium magnet having a terbium (Tb) content of 2.0 wt% or less, the residual magnetic flux density can be increased while suppressing the amount of terbium used.

  As described above, when using a neodymium magnet containing neodymium (Nd), iron (Fe), and terbium (Tb) as a permanent magnet of a rotor of a permanent magnet motor from the graphs shown in FIGS. 9 and 10, The content of terbium (Tb) is set within the range of 0.5% by weight and 2% by weight when the rotor has a 4-pole structure, and 0.4% by weight when the rotor has a 6-pole structure. And within the range of 2% by weight, when the rotor has an 8-pole structure, it is set within the range of 0.3% by weight and 2% by weight, and when the rotor has a 10-pole structure, 0.2%. It can be understood that it is preferable to set within the range of wt% and 2 wt%.

In the permanent magnet motors 100 to 400 of the first to fourth embodiments, one linear magnet insertion hole is formed in the main magnetic pole of the rotor and one permanent magnet is inserted in the magnet insertion hole. The number and shape of the magnet insertion holes formed in the magnetic pole and the number and shape of the permanent magnets inserted into the magnet insertion holes are not limited to this.
A fifth embodiment of the permanent magnet motor of the present invention is shown in FIG.
A permanent magnet motor 500 according to the fifth embodiment shown in FIG. 6 includes a stator 510 and a rotor 520.
In the present embodiment, the stator 510 is provided with nine teeth 512 (slots 515), and the stator winding is wound around the teeth 512 by a concentrated winding method.
Further, the number of poles of the main magnetic pole of the rotor 520 is set to 6. That is, the rotor 520 has a hexapole structure (6P).
Furthermore, each main magnetic pole is formed with a first magnet insertion hole 521a and a second magnet insertion hole 521b. The first magnet insertion hole 521a and the second magnet insertion hole 521b protrude to the axial center P side so that a central bridge portion is formed at the center in the circumferential direction of the main magnetic pole (location intersecting the d axis). It is arranged in a V shape (recessed on the outer peripheral side). In addition, the first permanent magnet 322a and the second permanent magnet 322b having a quadrangular cross-sectional shape perpendicular to the axial direction are inserted into the first magnet insertion hole 521a and the second magnet insertion hole 521b. .

A sixth embodiment of the permanent magnet motor of the present invention is shown in FIG.
A permanent magnet motor 600 of the sixth embodiment shown in FIG. 7 includes a stator 610 and a rotor 620.
In the present embodiment, the stator 610 is provided with 24 teeth 612 (slots 615), and the stator winding is wound around the teeth 612 by a distributed winding method.
The number of poles of the main magnetic pole of the rotor 620 is set to 4. That is, the rotor 620 has a four-pole structure (4P).
Further, in each main magnetic pole, a magnet insertion hole 621 having a first insertion portion 621a, a second insertion portion 621b, and a third insertion portion 621c protrudes toward the axial center P side (depresses on the outer peripheral side). It has a trapezoidal shape. That is, the second insertion portion 621b is arranged at the center in the circumferential direction of the main magnetic pole (location intersecting the d-axis) so as to extend linearly in a direction perpendicular to the d-axis, and the first insertion portion 621a. And the third insertion portion 621c are connected to both ends of the second insertion portion 621b, and are along the q axis of the adjacent auxiliary magnetic pole (a line connecting the axial center P and the circumferential center of the outer peripheral surface of the auxiliary magnetic pole). It is arranged to extend. In addition, the first permanent magnet 622a to the third permanent magnet 622c having a quadrangular cross-sectional shape orthogonal to the axial direction are inserted into the first insertion portion 621a to the third insertion portion 621c.

In the first to sixth embodiments, the case where the inner peripheral surface (tooth tip surface) of the stator and the outer peripheral surface of the rotor are formed in a circular shape or an arc shape centering on the shaft center P has been described. The shapes of the inner peripheral surface of the stator and the outer peripheral surface of the rotor are not limited to this.
FIG. 8 shows a sixth embodiment of the permanent magnet motor of the present invention in which the shape of the outer peripheral surface of the rotor is changed.

A permanent magnet electric motor 700 of the sixth embodiment shown in FIG. 8 includes a stator 710 and a rotor 720.
The outer peripheral surface 720a of the rotor 720 has first sections 720A, 720B, 720C, and 720D corresponding to the main magnetic poles A, B, C, and D and auxiliary magnetic poles AB, BC, and CD, as viewed in a cross section perpendicular to the axial direction. The second portions 720AB, 720BC, 720CD, 720DA corresponding to DA are arranged alternately.
The first portions 720A to 720D have a first curved shape that intersects the d-axis of the main magnetic poles A to D and protrudes to the outer peripheral side of the rotor 720. Further, the second portions 720AB to 720DA have a second curved shape that intersects with the q axis of the auxiliary magnetic poles AB to DA and protrudes to the outer peripheral side of the rotor 720. The first curved shape is an arc shape having a radius Rd with the axis center P on the d axis as the center of curvature. The second curved line shape is an arc shape having a radius Rq with the center of curvature at a point S on the q axis that is away from the axial center P in the direction opposite to the second portion. The first portions 720A to 720D and the second portions 720AB to 720DA are connected at connection points 720a1, 720a2 to 720d1, and 720d2. The opening angles of the first portions 720A to 720D are set in consideration of, for example, efficiency.
The radius Rq of the second portions 720AB to 720DA is larger than the radius Rd of the first portions 720A to 720D (Rq> Rd). Accordingly, the gap between the outer peripheral surface 720a of the rotor 720 (second portion 720AB to 720DA) and the inner peripheral surface of the stator 710 (tooth tip surface 714a) along the q-axis of the auxiliary magnetic poles AB to DA. G2 is a gap between the outer peripheral surface 720a (first portion 720A to 720D) of the rotor 720 and the inner peripheral surface (tooth tip surface 714a) of the stator 710 along the d-axis of the main magnetic poles A to D. It becomes larger than G1 (G2> G1).

Magnetic flux from the stator to the rotor and magnetic flux from the rotor to the stator flows through the auxiliary magnetic pole between the main magnetic poles. When the outer peripheral surface of the rotor has a circular shape with the same distance from the shaft center, the magnetic flux density of the magnetic flux flowing through the auxiliary magnetic pole becomes very high, and the permanent magnet is easily demagnetized.
In this embodiment, the outer peripheral surface of the rotor 720 is formed such that the gap G2 along the q axis is larger than the gap G1 along the d axis. Thereby, compared with the case where the outer peripheral surface of a rotor is formed in circular shape, the magnetic flux which flows into an auxiliary | assistant magnetic pole decreases, and a magnetic flux density becomes low.
Therefore, in the permanent magnet motor having the configuration of the present embodiment, a neodymium magnet having a small terbium content can be used as compared with the case where the outer peripheral surface of the rotor is formed in a circular shape having the same distance from the shaft center. . In other words, when a neodymium magnet having the same terbium content is used, a thin neodymium magnet can be used.
For example, when using a neodymium magnet containing neodymium (Nd), iron (Fe) and terbium (Tb) as described above, the content of terbium (Tb) is set to 0.1 when the rotor has a quadrupole structure. Within the range of 45% and 2% by weight, within the range of 0.36% and 2% by weight when the rotor has a 6-pole structure, and 0.27% by weight when the rotor has an 8-pole structure. When the rotor has a 10-pole structure within the range of 2% by weight, the residual magnetic flux density can be increased while preventing demagnetization by setting within the range of 0.18% by weight and 2% by weight.

The raw material (ore) of neodymium contains other metals such as praseodymium (Pr) in addition to metals such as neodymium (Nd) and iron (Fe) constituting the neodymium magnet. Conventionally, metals such as neodymium and iron constituting neodymium magnets have been separated from other metals including praseodymium from raw materials of neodymium.
On the other hand, in recent years, it has been found that even if the neodymium magnet contains praseodymium, the magnetic properties of the neodymium magnet do not change significantly if the component ratio of neodymium is substantially the same.
Therefore, in the permanent magnet motors of the first to seventh embodiments, neodymium magnets including neodymium (Nd), iron (Fe) and terbium (Tb) can be used, or neodymium (Nd) and praseodymium (Pr). A neodymium magnet containing iron (Fe) and terbium (Tb) can also be used.
When a neodymium magnet containing neodymium (Nd), praseodymium (Pr), iron (Fe) and terbium (Tb) is used, a process for separating praseodymium from the raw material of neodymium is not required, so the neodymium magnet is manufactured at a low cost. Therefore, a permanent magnet motor having a neodymium magnet can be manufactured at low cost.

The present invention is not limited to the configuration described in the embodiment, and various changes, additions, and deletions are possible.
The shape and number of magnet insertion holes formed in the main magnetic pole of the rotor can be set as appropriate.
The shape and the number of permanent magnets inserted into the magnet insertion holes of the main magnetic pole of the rotor are appropriately set according to the shape of the magnet insertion holes.
The number of teeth (number of slots) of the stator of the permanent magnet motor is set as appropriate.
As a method of winding the stator winding around the teeth, various methods such as a concentrated winding method and a distributed winding method can be used. When the concentrated winding method is used, the stator teeth (slots) are provided 1.5 times the number of main poles of the rotor. When the distributed winding method is used, the stator teeth (slots) are provided. ) Is typically provided 6 times as many as the number P of the main poles of the rotor.
In the embodiment, the outer peripheral surface of the rotor is formed by a first portion that intersects the d-axis and a second portion that intersects the q-axis, and the first portion and the second portion are formed into arc shapes having different radii. Although formed, the first portion and the second portion can be formed in a shape other than the arc shape. As a method for reducing the amount of magnetic flux flowing through the auxiliary magnetic pole as compared with the case of using a circular rotor having the same distance from the shaft center to the outer peripheral surface of the rotor, the gap along the q axis is d Any method can be used as long as it is larger than the gap along the axis, and the outer peripheral surface of the rotor is not limited to the method of forming the first portion and the second portion.
The compressor of the present invention is not limited to a rotary compressor having a rotary type compression mechanism, and can be configured as a compressor having various configurations such as a scroll compressor having a scroll type compression mechanism.
The permanent magnet motor of the present invention can be used as a drive motor for various devices other than a compressor.
Each structure demonstrated by embodiment can also be used independently, and can also be used combining the some structure selected suitably.

The present invention can also be configured as follows.
(Aspect 1) A permanent magnet motor including a stator and a rotor having a permanent magnet, and having a gap between an outer peripheral surface of the rotor and an inner peripheral surface of the stator, wherein the rotation The child has a quadrupole structure, and a neodymium magnet containing neodymium, iron and terbium is arranged in each pole, and the terbium content is in the range of 0.5 wt% and 2 wt%. Permanent magnet motor characterized by
(Aspect 2) A permanent magnet motor including a stator and a rotor having a permanent magnet, wherein the rotor has a six-pole structure, and a neodymium magnet containing neodymium, iron, and terbium is disposed in each pole. The permanent magnet motor is characterized in that the terbium content is in the range of 0.4 wt% and 2 wt%.
(Aspect 3) A permanent magnet motor including a stator and a rotor having a permanent magnet, wherein the rotor has an 8-pole structure, and a neodymium magnet containing neodymium, iron, and terbium is disposed in each pole. The permanent magnet motor is characterized in that the terbium content is in the range of 0.3 wt% and 2 wt%.
(Aspect 4) A permanent magnet motor including a stator and a rotor having a permanent magnet, wherein the rotor has a 10-pole structure, and a neodymium magnet containing neodymium, iron, and terbium is disposed in each pole. The permanent magnet motor is characterized in that the terbium content is in the range of 0.2 wt% and 2 wt%.
(Aspect 5) The permanent magnet motor according to any one of aspects 1 to 4, wherein the neodymium magnet includes neodymium, praseodymium, iron, and terbium.
(Aspect 6) The permanent magnet electric motor according to any one of aspects 1 to 5, wherein the gap along the d-axis of the main magnetic pole is smaller than the gap along the q-axis of the auxiliary magnetic pole. A permanent magnet electric motor characterized by having
(Aspect 7) The permanent magnet motor according to Aspect 6, wherein the outer peripheral surface of the rotor has a first portion that intersects the d-axis of the main magnetic pole as viewed in a cross section orthogonal to the axial direction, and q of the auxiliary magnetic pole The length of the second portion from the axial center along the q-axis is greater than the length of the first portion from the axial center along the d-axis. A permanent magnet motor characterized by being formed to be small.
(Aspect 8) A compressor including a compression mechanism section and an electric motor that drives the compression mechanism section, wherein the permanent magnet electric motor according to any one of claims 1 to 7 is used as the electric motor. The compressor characterized by having.

DESCRIPTION OF SYMBOLS 10 Compressor 20 Airtight container 21 Suction port 22 Discharge port 30 Compression mechanism part 31 Cylinder 32 Eccentric rotor 33 Compression chamber 34, 35 Bearing part 36 Oil reservoir 40 Accumulator 41 Suction pipe 100, 200, 300, 400, 500, 600, 700 Permanent magnet motor 110, 210, 310, 410, 510, 610, 710 Stator 111, 211, 311, 411, 511, 611, 711 Yoke 112, 212, 312, 412, 512, 612, 712 Teeth 113, 213, 313, 413, 513, 613, 713 Teeth base 114, 214, 314, 414, 514, 614, 714 Teeth tip 114a, 214a, 314a, 414a, 514a, 614a, 714a Teeth tip surface 116 Stator winding 120, 220, 320, 20, 520, 620, 720 Rotor 120a, 220a, 320a, 420a, 520a, 620a, 720a Outer peripheral surface 121, 221, 321, 421, 521a, 521b, 621, 721 Magnet insertion holes 122, 222, 322, 422, 522a, 522b, 622a, 622b, 622c, 722 Permanent magnet 130, 230, 330, 430, 530, 630, 730 Rotating shaft 621a, 621b, 621c Insertion part 720A-720D First part 720AB-720DA Second part

Claims (7)

A permanent magnet motor that drives a compression mechanism of the compressor,
Comprising a stator and a rotor having permanent magnets;
Having a gap between the outer peripheral surface of the rotor and the inner peripheral surface of the stator ,
The rotor has main magnetic poles and auxiliary magnetic poles alternately arranged along the circumferential direction when viewed in a cross section perpendicular to the axial direction, and a magnet insertion in which the permanent magnet is inserted into each main magnetic pole. Holes are formed,
The gap along the d-axis of the main magnetic pole is configured to be smaller than the gap along the q-axis of the auxiliary magnetic pole,
The rotor has a four-pole structure in which the number of the main poles is four , and the magnet insertion hole contains neodymium, iron, and terbium, and the terbium content is 0.5% by weight. A permanent magnet motor in which a neodymium magnet in the range of 2% by weight is inserted . A permanent magnet motor that drives a compression mechanism of the compressor,
Comprising a stator and a rotor having permanent magnets;
Having a gap between the outer peripheral surface of the rotor and the inner peripheral surface of the stator ,
The rotor has main magnetic poles and auxiliary magnetic poles alternately arranged along the circumferential direction when viewed in a cross section perpendicular to the axial direction, and a magnet insertion in which the permanent magnet is inserted into each main magnetic pole. Holes are formed,
The gap along the d-axis of the main magnetic pole is configured to be smaller than the gap along the q-axis of the auxiliary magnetic pole,
The rotor has a six-pole structure in which the number of main poles is six , and the magnet insertion hole contains neodymium, iron, and terbium, and the terbium content is 0.4 wt%. A permanent magnet motor in which a neodymium magnet in the range of 2% by weight is inserted . A permanent magnet motor that drives a compression mechanism of the compressor,
Comprising a stator and a rotor having permanent magnets;
Having a gap between the outer peripheral surface of the rotor and the inner peripheral surface of the stator ,
The rotor has main magnetic poles and auxiliary magnetic poles alternately arranged along the circumferential direction when viewed in a cross section perpendicular to the axial direction, and a magnet insertion in which the permanent magnet is inserted into each main magnetic pole. Holes are formed,
The gap along the d-axis of the main magnetic pole is configured to be smaller than the gap along the q-axis of the auxiliary magnetic pole,
The rotor has an 8-pole structure in which the number of the main poles is 8 , and the magnet insertion hole contains neodymium, iron, and terbium, and the terbium content is 0.3% by weight. A permanent magnet motor in which a neodymium magnet in the range of 2% by weight is inserted . A permanent magnet motor that drives a compression mechanism of the compressor,
Comprising a stator and a rotor having permanent magnets;
Having a gap between the outer peripheral surface of the rotor and the inner peripheral surface of the stator ,
The rotor has main magnetic poles and auxiliary magnetic poles alternately arranged along the circumferential direction when viewed in a cross section perpendicular to the axial direction, and a magnet insertion in which the permanent magnet is inserted into each main magnetic pole. Holes are formed,
The gap along the d-axis of the main magnetic pole is configured to be smaller than the gap along the q-axis of the auxiliary magnetic pole,
The rotor has a 10-pole structure in which the number of the main poles is 10 , and the magnet insertion hole contains neodymium, iron, and terbium, and the terbium content is 0.2% by weight. A permanent magnet motor in which a neodymium magnet in the range of 2% by weight is inserted . The permanent magnet motor according to any one of claims 1 to 4,
The neodymium magnet includes neodymium, praseodymium, iron, and terbium. The permanent magnet motor according to any one of claims 1 to 5 ,
The outer peripheral surface of said rotor, as viewed in cross section perpendicular to the axial direction, is configured with a first portion intersecting the d-axis of the main magnetic pole, the second portion intersecting with the q-axis of the auxiliary magnetic, The length of the second part from the axial center along the q-axis is formed to be smaller than the length of the first part from the axial center along the d-axis. Permanent magnet motor. A compressor including a compression mechanism and an electric motor that drives the compression mechanism;
A compressor using the permanent magnet motor according to any one of claims 1 to 6 as the electric motor.

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