WO2015198444A1

WO2015198444A1 - Interior permanent magnet electric motor, compressor, and refrigerating and air-conditioning device

Info

Publication number: WO2015198444A1
Application number: PCT/JP2014/066975
Authority: WO
Inventors: 昌弘仁吾; 和慶土田
Original assignee: 三菱電機株式会社
Priority date: 2014-06-26
Filing date: 2014-06-26
Publication date: 2015-12-30

Abstract

An interior permanent magnet electric motor (1) is equipped with a rotor (5) having a plurality of permanent magnets (19) and a stator (3). The rotor is equipped with a rotor iron core. The rotor iron core has a plurality of magnet insertion holes (21). The permanent magnets are inserted into the respective magnet insertion holes. The magnet insertion holes are each formed in a shape protruding toward the center side of the rotor. The magnet insertion holes each have a hole inside line (53), a hole outside line (55), and a pair of hole side-lines (57). The hole outside line includes a pair of recess portions (61) at the ends thereof. The depth of the recess portions is 10-40% of the thickness of the permanent magnets.

Description

Permanent magnet embedded electric motor, compressor, refrigeration air conditioner

The present invention relates to a permanent magnet embedded electric motor, a compressor, and a refrigeration air conditioner.

In the permanent magnet embedded type electric motor, when the magnet insertion hole is formed to be convex inward in the radial direction, the side ends of the magnet and the magnet insertion hole are arranged close to the outer peripheral surface of the rotor. Since the magnet and the side end of the magnet insertion hole on the outer periphery of the rotor have a low permeability with respect to the iron core at the center of the magnetic pole, the magnetic flux generated by the stator coil is difficult to interlink. Therefore, the magnetic flux when the stator is energized tends to concentrate on the rotor core part adjacent to the side end of the magnet insertion hole, and when the magnetic flux generated by the stator coil increases, the side end of the permanent magnet adjacent to the iron core part It may become easy to demagnetize.

In the electric motor of Patent Document 1, as viewed from the axial direction of the rotor, in each of the magnetic poles, the magnet and the magnet insertion hole are convex toward the inner peripheral side of the rotor, and the end of the magnet is directed toward the tip. The width is narrow, and the end of the magnet has a notch formed at the center line side of the magnetic pole. By such a notch, an attempt was made to reduce the portion that is easily demagnetized. That is, by making it difficult for the magnet to be demagnetized, it has been intended to suppress the occurrence of magnetic flux variations and thus to suppress the reduction in motor performance.

JP 2013-212035 A

However, in the configuration disclosed in Patent Document 1, since the notch is provided in the portion where the magnet is easily demagnetized, the size of the magnet is reduced, and the amount of magnetic flux generated from the magnet is reduced. Another problem is that it is difficult to construct an efficient motor.

The present invention has been made in view of such circumstances, and in a rotor having a magnet insertion hole formed in a convex shape toward the center side of the rotor, while avoiding a decrease in the magnetic flux amount of the permanent magnet. An object of the present invention is to provide a high-efficiency permanent magnet embedded electric motor that is difficult to demagnetize.

In order to achieve the above-mentioned object, the present invention provides an embedded permanent magnet electric motor including a rotor having a plurality of permanent magnets and a stator, wherein the rotor includes a rotor iron core, and the rotor iron core includes a plurality of magnets. Each of the permanent magnets is inserted into the magnet insertion hole, and each of the magnet insertion holes is formed in a convex shape toward the center side of the rotor. Each has a hole inner line, a hole outer line, and a pair of hole side lines, each of the hole outer lines includes a pair of recesses at the end, and the depth of the recess is 10 to 40% of the thickness of the permanent magnet.
Furthermore, the compressor of the present invention for achieving the same object is a compressor provided with an electric motor and a compression element in an airtight container, and the electric motor is the above-described permanent magnet embedded type of the present invention. It is an electric motor.
Furthermore, the refrigerating and air-conditioning apparatus of the present invention for achieving the same object includes the above-described compressor of the present invention as a component of the refrigeration circuit.

According to the present invention, the imbalance of the magnetic flux density on the outer surface of the rotor can be suppressed and the vibration can be reduced without substantially changing the effect of reducing the magnetic attractive force generated by the stator magnetic flux.

It is a figure which shows the cross section orthogonal to the rotation centerline of the permanent magnet embedded electric motor of Embodiment 1 of this invention. In FIG. 1, it is a figure which expands and shows a rotor. In FIG. 2, it is a figure which expands and shows a magnet insertion hole. In FIG. 3, it is a figure which shows the state by which the permanent magnet is not inserted in the magnet insertion hole. It is a figure of the same aspect as FIG. 3, and is a figure explaining the dimension of each part of a magnet insertion hole. It is a figure corresponding to FIG. 2 regarding the 1st related technique which does not have a recessed part in a magnet insertion hole. It is a figure explaining one advantage of this Embodiment 1. FIG. It is a figure explaining another one advantage of this Embodiment 1. FIG. It is a figure corresponding to FIG. 2 regarding the 2nd related technique in which the recessed part of the magnet insertion hole was formed in the inappropriate aspect. It is a graph which shows the relationship between the induced voltage before demagnetizing current supply, and D / T ratio. It is a graph which shows the relationship between the induced voltage after energization of a demagnetizing current, and D / T ratio. It is a longitudinal cross-sectional view of the rotary compressor of Embodiment 2 of this invention. It is a figure which shows the refrigerating air conditioner of Embodiment 3 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

Embodiment 1 FIG.
FIG. 1 is a view showing a cross section orthogonal to the rotation center line of the permanent magnet embedded electric motor according to Embodiment 1 of the present invention. FIG. 2 is an enlarged view of the rotor in FIG. FIG. 3 is an enlarged view of the magnet insertion hole in FIG. FIG. 4 is a diagram showing a state where no permanent magnet is inserted into the magnet insertion hole in FIG. 3.

As shown in FIGS. 1 to 4, the embedded permanent magnet electric motor 1 includes a stator 3 and a rotor 5 that is rotatably provided to face the stator 3. The stator 3 has a plurality of tooth portions 7. Each of the plurality of tooth portions 7 is adjacent to another tooth portion 7 via a corresponding slot portion 9. The plurality of teeth portions 7 and the plurality of slot portions 9 are arranged so as to be alternately arranged at equal intervals in the circumferential direction. A known stator winding (not shown) is wound around each of the plurality of tooth portions 7 in a known manner.

The rotor 5 has a rotor iron core 11 and a shaft 13. The shaft 13 is connected to the axial center portion of the rotor core 11 by shrink fitting, press fitting, or the like, and transmits rotational energy to the rotor core 11. An air gap 15 is secured between the outer peripheral surface of the rotor and the inner peripheral surface of the stator.

In such a configuration, the rotor 5 is held inside the stator 3 via the air gap 15 so as to be rotatable about a rotation center line (rotation center of the rotor) CL. Specifically, a current of a frequency synchronized with the command rotational speed is supplied to the stator 3 to generate a rotating magnetic field and rotate the rotor 5. The air gap 15 between the stator 3 and the rotor 5 is a gap of 0.3 to 1 mm.

Next, the configuration of the stator 3 and the rotor 5 will be described in detail. The stator 3 has a stator iron core 17. The stator iron core 17 is formed by punching electromagnetic steel sheets having a thickness of about 0.1 to 0.7 mm per sheet into a predetermined shape and laminating a predetermined number of electromagnetic steel sheets while being fastened with caulking. Here, an electromagnetic steel sheet having a thickness of 0.35 mm is used.

The stator iron core 17 is formed with nine tooth portions 7 arranged at substantially equal intervals in the circumferential direction on the radially inner side. The teeth part 7 is formed radially. A corresponding slot portion 9 is formed in a region between adjacent tooth portions 7 in the stator core 17.

Each tooth portion 7 extends in the radial direction and protrudes toward the rotation center line CL. Further, most of the tooth portion 7 has a substantially equal circumferential width from the radially outer side to the radially inner side, but the tooth tip portion is located at the tip end that is the radially inner side of the tooth portion 7. 7a is formed. Each of the tooth tip portions 7a is formed in an umbrella shape in which both side portions extend in the circumferential direction.

A stator winding (not shown) that constitutes a coil (not shown) that generates a rotating magnetic field is wound around the teeth portion 7. The coil is formed by winding a magnet wire directly around a tooth portion via an insulator. This winding method is called concentrated winding. The coil is connected to a three-phase Y connection. The number of turns and the wire diameter of the coil are determined according to the required characteristics (rotation speed, torque, etc.), voltage specifications, and the cross-sectional area of the slot. Here, the divided teeth are developed in a strip shape to facilitate winding, and a magnet wire having a wire diameter of about 1.0 mm is wound around the teeth of each magnetic pole for about 80 turns. After winding, the divided teeth are rounded and welded. Thus, the stator is configured.

Near the center of the stator 3, a shaft 13 that is rotatably held is disposed. The rotor 5 is fitted to the shaft 13. The rotor 5 has a rotor iron core 11, and the rotor iron core 11 is also punched out from a magnetic steel sheet having a thickness of about 0.1 to 0.7 mm into a predetermined shape, like the stator iron core 17, and a predetermined number of electromagnetic cores. It is constructed by laminating steel plates with caulking. Here, an electromagnetic steel sheet having a thickness of 0.35 mm is used.

The rotor 5 is a magnet-embedded type, and a plurality (six in this example) of permanent magnets 19 magnetized so that N poles and S poles are alternately arranged inside the rotor core 11. Is provided. Each of the permanent magnets 19 is curved in an arc shape when viewed in a cross section having the rotation center line CL of the rotor 5 as a perpendicular line, and the convex portion side of the arc shape is disposed on the center side of the rotor 5. Further, each of the permanent magnets 19 is curved so as to be line symmetric with respect to the corresponding magnetic pole center line MC.

More specifically, a number of magnet insertion holes 21 corresponding to the plurality of permanent magnets 19 are formed in the rotor core 11, and the corresponding permanent magnets 19 are inserted into the plurality of magnet insertion holes 21, respectively. Yes. One permanent magnet 19 is inserted into one magnet insertion hole 21. As can be seen, the recess 61 and the magnet insertion hole 21 are curved so as to be line symmetric with respect to the corresponding magnetic pole center line MC.

The number of magnetic poles of the rotor 5 may be any number as long as it is 2 or more, but in this example, the case of 6 poles is illustrated. Here, a ferrite magnet is used as the permanent magnet 19, and the inner and outer peripheral surfaces of the ferrite magnet are formed in a constant concentric arc shape, and the thickness T in the curved radial direction of the ferrite magnet is uniformly maintained at about 6 mm. I try to do it.

Further, as the permanent magnet 19, a magnet to which an orientation magnetic field is applied from the center of a concentric arc as shown by an arrow MD in FIG. 3 is used, and a magnet is inserted into a magnet insertion hole having a shape along the magnet. Is inserted.

The magnet type may be, for example, a rare earth magnet mainly composed of neodymium, iron, or boron, and the shape of the magnet is not limited to an arc shape, but may be a flat plate or a flat plate. It is also possible to form a magnetic pole by arranging a plurality of the above.

The caulking 33 is provided on the magnetic pole center line MC, thereby fixing the lamination of the iron core portion on the radially outer side of the magnet insertion hole 21 in the rotor 5 and suppressing deformation during manufacture.

A plurality of air holes 35 and a plurality of rivet holes 37 arranged alternately at equal intervals in the circumferential direction are provided on the radially inner side of the magnet insertion hole 21, and the caulking 33 corresponds to the corresponding rivet hole 37. It is also provided between the pair of magnet insertion holes 21.

Next, the permanent magnet 19 and the magnet insertion hole 21 will be described in detail. The permanent magnet 19 and the magnet insertion hole 21 are formed symmetrically with respect to the corresponding magnetic pole center line ML when viewed in a cross section with the rotation center line CL of the rotor 5 as a perpendicular line.

The permanent magnets 19 each have an inner outer surface 43, an outer outer surface 45, and a pair of side outer surfaces 47 as viewed in a cross section having the rotation center line CL of the rotor 5 as a perpendicular line. It should be noted that the outer side and the inner side of the inner outer surface and the outer outer surface indicate whether they are the inner side or the outer side in the radial direction in a relative comparison when viewed from a plane having the rotation center line CL as a perpendicular line.

Each of the magnet insertion holes 21 has a hole inner line 53, a hole outer line 55, and a pair of hole side lines 57 as the outline of the hole when viewed in a cross section with the rotation center line CL of the rotor 5 as a perpendicular line. is doing. It should be noted that the outer side and the inner side of the hole inner line and the hole outer line also indicate whether they are the radially inner side or the outer side in a relative comparison with respect to the plane having the rotation center line CL as a perpendicular line. To do.

The outer outer surface 45 is mostly constituted by a first arc surface having a first arc radius, and the hole outer line 55 is also mostly constituted by a first arc surface 55a having a first arc radius. ing. On the other hand, the inner outer surface 43 includes a second arc surface 43a having a second arc radius larger than the first arc radius, and a straight surface 49. Similarly, the hole inner line 53 has a second arc radius. A second arc surface 53a and a straight surface 59 are included.

Since the permanent magnet 19 is inserted into the magnet insertion hole 21, the first arc radius and the second arc radius related to the magnet insertion hole 21, and the first arc radius and the second arc radius related to the permanent magnet 19, Are not the same when viewed strictly, but the permanent magnet 19 is fitted into the magnet insertion hole 21 and, for the sake of easy understanding of the explanation, the same language is used on the permanent magnet side and the magnet insertion hole side. Shall be used.

The first arc radius and the second arc radius have a common radius center, and the common radius center is on the outer side in the radial direction than the permanent magnet 19 and the magnet insertion hole 21 and corresponds. It exists on the magnetic pole center line ML. In other words, the inner outer surface 43 (hole inner line 53) and the outer outer surface 45 (hole outer line 55) are concentrically formed, and the center of the first arc surface and the center of the second arc surface are made of permanent magnets. It coincides with the alignment center (alignment focal point). In addition, the arrow of the code | symbol MD in FIG. 3 has shown the direction of orientation typically.

In addition, the arc shape regarding a magnet insertion hole and a permanent magnet is an example of the shape of a magnet insertion hole and a permanent magnet, and this invention uses the rotor which has such a substantially arc-shaped magnet insertion hole and a permanent magnet. The rotor includes a magnet insertion hole and a permanent magnet that are formed in a convex shape toward the center of the rotor.

The straight surface 49 and the straight surface 59 extend in a direction perpendicular to the magnetic pole center line ML when viewed in a cross section having the rotation center line CL of the rotor 5 as a perpendicular line.

Further, the pair of side outer surfaces 47 respectively connect corresponding end portions of the inner outer surface 43 and the outer outer surface 45, and the pair of hole side lines 57 respectively correspond to the corresponding ends of the hole inner line 53 and the hole outer line 55. The parts are tied together.

Each of the hole outer lines 55 of the magnet insertion hole 21 includes a first arc surface 55a that occupies most of the hole outer line 55 and a pair of recesses 61. The pair of recesses 61 are located on both sides of the first arc surface 55 a of the hole outer line 55, that is, located at the corresponding hole side line 57 end of the hole outer line 55. Each of the recesses 61 extends toward the corresponding magnetic pole center line ML in the circumferential direction. The bottoms of the recesses 61 are each formed in an arc shape.

As shown in FIG. 5, in a state where the permanent magnet 19 is inserted into the magnet insertion hole 21, the concave portion 61 of the magnet insertion hole 21 and the outer outer surface 45 of the permanent magnet 19 are greatly separated from each other. A gap 61 a that is a nonmagnetic region is formed between the outer surface 45 and the outer surface 45.

The depth D of the recess 61 is smaller than the thickness T of the permanent magnet 19, and for example, the depth D of the recess 61 is 1 mm with respect to the thickness T = 6 mm of the permanent magnet 19. D / T corresponds to 16.7%. The depth D of the recess 61 indicates the distance between the bottom of the recess 61 and the outer outer surface 45 of the permanent magnet 19 when the permanent magnet 19 is inserted into the magnet insertion hole 21. When there is a notch or chamfer at the magnet end, the distance between the bottom of the recess and the outer outer surface of the permanent magnet at the portion excluding them becomes the depth of the recess. Alternatively, when the outer outer surface of the magnet does not exist inside the concave portion (facing the concave portion), the depth of the concave portion is the distance between the virtual surface obtained by extending the outer outer surface of the magnet to the facing surface of the concave portion and the bottom portion of the concave portion. means. The magnet thickness T means the magnet thickness at the thickest part of the magnet. When there are notches, chamfers, etc. at the end of the magnet, the thickness at those removed sites is the magnet thickness.

The hole side line 57 of the magnet insertion hole 21 is disposed close to the rotor outer peripheral surface 5a. Between the hole side line 57 of the magnet insertion hole 21 and the rotor outer peripheral surface 5a, the side wall thin portion 11a having a uniform thickness exists. Each of these side end thin portions 11a serves as a path for a short-circuit magnetic flux between adjacent magnetic poles, and is preferably as thin as possible. Here, the minimum width that can be pressed is set to about 0.35 mm of the thickness of the electromagnetic steel sheet.

Next, the operation of the embedded permanent magnet electric motor according to the first embodiment will be described with reference to the first related technique shown in FIG. 6 and the second related technique shown in FIG. FIG. 6 is a view corresponding to FIG. 2 relating to the first related technique in which the magnet insertion hole has no recess. FIG. 7 is a diagram for explaining one advantage of the first embodiment, and FIG. 8 is a diagram for explaining another advantage of the first embodiment. FIG. 9 is a view corresponding to FIG. 2 relating to a second related technique in which the concave portion of the magnet insertion hole is formed in an inappropriate manner.

First, as in the first related art shown in FIG. 6, when a recess is not provided at the end of the hole outer line of the magnet insertion hole, the permanent magnet inserted in a convex shape toward the center side of the rotor In a rotor having a hole, in particular, the boundary between the hole outer line and the hole side line is close to the magnet, so that the magnet magnetic flux M1 generated from the magnet surface tends to be short-circuited to the magnet side surface.

On the other hand, in the first embodiment, since the above-described recess 61 is provided, a gap 61a is generated at the boundary between the hole outer line 55 and the hole side line 57. As described above, it is difficult for the magnetic flux M2 generated from the magnet surface to be short-circuited to the magnet side surface, and the amount of effective magnetic flux linked to the stator can be increased.

However, on the other hand, as in the second related technique shown in FIG. 9, when the concave portion is too deep, the opening width (the interval between the bottom portions of the pair of concave portions) for generating the magnet magnetic flux M3 from the rotor is narrowed. There is a problem that the amount of flux linkage to the stator is reduced. That is, there is an unfavorable problem that the concave portion hinders the magnetic flux M3 from the rotor to the stator, and the induced voltage decreases. This will be described with reference to FIG.

FIG. 10 is a graph of the induced voltage characteristics before the current of the demagnetization phase is passed through the rotor when D / T is changed. Note that the induced voltage on the vertical axis in FIG. 10 is based on the induced voltage when the D / T with no recess is 0% as a reference 100%. The induced voltage is a voltage generated by a magnetic flux interlinked with the stator from the rotor when the rotor rotates, and the effective magnetic flux amount interlinked with the stator can be evaluated by the magnitude of the induced voltage. As shown in FIG. 10, when the recess is deep (when D / T exceeds 40%), the recess hinders the magnetic flux from the rotor to the stator, and the induced voltage is greatly reduced. In the first aspect, by setting D / T to 10 to 40%, it is possible to suppress the leakage magnetic flux at the end of the permanent magnet as compared with the case where no recess is provided (D / T = 0%). It is possible to increase the induced voltage.

Returning to FIG. 6, when a recess is not provided as in the first related art, in a rotor having a permanent magnet insertion hole formed in a convex shape toward the center side of the rotor, a magnet and a magnet are inserted. The end portion of the hole close to the outer periphery of the rotor (in the example described above, the portion corresponding to the side outer surface 47 and the hole side line 57) is generated by the stator coil because the permeability is lower than the iron core at the center of the magnetic pole. Magnetic flux M4 is difficult to interlink. Therefore, the magnetic flux when the stator is energized tends to concentrate on the iron core portion between the end of the magnet insertion hole near the outer periphery of the rotor and the outer periphery of the rotor, and when the magnetic flux M4 generated by the stator coil increases, the magnetic flux approaches the iron core portion. There is an inconvenience that the end portion of the permanent magnet (in the above described example, the portion corresponding to the side outer surface 47) is easily demagnetized.

On the other hand, in the first embodiment, since the recess 61 described above is provided, a gap 61a is generated at the boundary between the hole outer line 55 and the hole side line 57. As described above, the magnetic flux M5 generated in the stator coil is less likely to be linked to the end portion of the permanent magnet, so that it is difficult to demagnetize. This will be described with reference to FIG.

FIG. 11 is a graph of induced voltage characteristics after a current of a demagnetization phase is passed through the rotor when D / T is changed. As can be seen from FIG. 11, the amount of demagnetization is smaller and the induced voltage is larger when the recess is provided, compared to the case where there is no recess (D / T = 0%). On the other hand, when the recessed portion is deep (D / T is larger than 40%), the recessed portion interferes with the magnetic flux from the rotor to the stator as in FIG. Accordingly, D / T = 10 to 40% is a preferable range. That is, in the first embodiment, by setting D / T to 10 to 40%, the induced voltage is compared with the case where there is no recess both before and after the demagnetizing current. It is possible to improve efficiency and reliability.

And by improving the induced voltage as described above, the motor current when the same torque is generated can be reduced, and as a result, the copper loss generated in the motor coil and the current loss generated in the inverter are reduced. Thus, a highly efficient motor and compressor can be configured. In addition, even if the amount of magnets used in the motor and the motor volume are reduced by the amount of improvement in the induced voltage, the design can be made with the same output as the conventional one, so that a small motor can be configured. Further, since the demagnetization characteristic is improved, the motor can be configured not to be demagnetized even when a larger current is applied to the motor than before, so that the reliability as a compressor as described later can be improved. At the same time, the operating range can be expanded. In particular, it is effective for ferrite magnets with low coercivity and rare earth magnets used at high temperatures. In addition, the rare earth magnet has a characteristic that the coercive force decreases as the temperature increases.

As described above, according to the first embodiment, in a rotor having a magnet insertion hole formed in a convex shape toward the center side of the rotor, demagnetization while avoiding a decrease in the magnetic flux amount of the permanent magnet. It is difficult to obtain a highly efficient permanent magnet embedded motor.

Embodiment 2. FIG.
Next, a rotary compressor equipped with the above-described permanent magnet embedded motor according to the first embodiment will be described. In the present invention, the type of the compressor is not limited to the rotary compressor.

FIG. 12 is a longitudinal sectional view of a rotary compressor equipped with a permanent magnet embedded type electric motor. The rotary compressor 260 is provided with the permanent magnet embedded electric motor (electric element) 1 of the first embodiment and the compression element 262 in the sealed container 261. Although not shown, refrigerating machine oil that lubricates each sliding portion of the compression element is stored at the bottom of the sealed container 261.

The compression element 262 includes, as main elements, a cylinder 263 provided in a vertically stacked state, a rotation shaft 264 that is the shaft 13 that is rotated by the permanent magnet embedded electric motor 1, and a piston 265 that is fitted into the rotation shaft 264. A pair of upper and lower

upper frames

266 and 266, each of which includes a vane (not shown) that divides the inside of the cylinder 263 into a suction side and a compression side, and a rotary shaft 264 that is rotatably inserted and closes an axial end surface of the cylinder 263. 267 and mufflers 268 mounted on the upper frame 266 and the lower frame 267, respectively.

The stator 3 of the permanent magnet embedded motor 1 is directly attached and held in the sealed container 261 by a method such as shrink fitting or welding. Electric power is supplied to the coil of the stator 3 from a glass terminal 269 fixed to the hermetic container 261.

The rotor 5 is disposed on the inner diameter side of the stator 3 via a gap (air gap 15), and a bearing portion (upper frame and lower frame) of the compression element 262 via a rotation shaft 264 at the center of the rotor 5. Is held in a freely rotatable state.

Next, the operation of the rotary compressor will be described. The refrigerant gas supplied from the accumulator 270 is sucked into the cylinder 263 through a suction pipe 271 fixed to the sealed container 261. When the embedded permanent magnet electric motor 1 is rotated by energization of the inverter, the piston 265 fitted to the rotating shaft 264 is rotated in the cylinder 263. Thereby, the refrigerant is compressed in the cylinder 263.

The refrigerant ascends in the sealed container 261 after passing through the muffler. At this time, refrigeration oil is mixed in the compressed refrigerant. When the mixture of the refrigerant and the refrigerating machine oil passes through the air hole provided in the rotor core, the separation of the refrigerant and the refrigerating machine oil is promoted, and the refrigerating machine oil can be prevented from flowing into the discharge pipe 272. In this way, the compressed refrigerant is supplied to the high-pressure side of the refrigeration cycle through the discharge pipe 272 provided in the sealed container 261.

In addition, although conventional R410A, R407C, R22, etc. may be used as the refrigerant of the rotary compressor, any refrigerant such as a low GWP (global warming potential) refrigerant can be applied. From the viewpoint of preventing global warming, a low GWP refrigerant is desired. As typical examples of the low GWP refrigerant, there are the following refrigerants.
(1) Halogenated hydrocarbon having a carbon double bond in the composition: for example, HFO-1234yf (CF3CF = CH2). HFO is an abbreviation for Hydro-Fluoro-Olefin, and Olefin is an unsaturated hydrocarbon having one double bond. The GFO of HFO-1234yf is 4.
(2) Hydrocarbon having a carbon double bond in the composition: for example, R1270 (propylene). GWP is 3, which is smaller than HFO-1234yf, but flammability is larger than HFO-1234yf.
(3) a mixture containing at least one of a halogenated hydrocarbon having a carbon double bond in the composition or a hydrocarbon having a carbon double bond in the composition: for example, a mixture of HFO-1234yf and R32 is there. Since HFO-1234yf is a low-pressure refrigerant, its pressure loss is large, and the performance of the refrigeration cycle (especially in an evaporator) tends to deteriorate. Therefore, a mixture with R32 or R41, which is a high-pressure refrigerant, is more effective than HFO-1234yf in practical use.

Even in the rotary compressor configured as described above, the same advantages as those of the first embodiment can be obtained by using the above-described permanent magnet embedded type electric motor.

Embodiment 3 FIG.
Moreover, as illustrated in FIG. 13, the present invention can be implemented as a refrigerating and air-conditioning apparatus 380 that includes the above-described compressor 260 as a component of a refrigeration circuit. The refrigeration circuit of the refrigerating and air-conditioning apparatus 380 includes at least a condenser 381, an evaporator 382, and an expansion device 383. The components other than the compressor including the condenser 381, the evaporator 382, and the expansion device 383 are configured. Is not particularly limited.

Although the contents of the present invention have been specifically described with reference to the preferred embodiments, various modifications can be made by those skilled in the art based on the basic technical idea and teachings of the present invention. It is self-explanatory.

1 permanent magnet embedded motor, 3 stator, 5 rotor, 5a rotor outer peripheral surface, 11 rotor iron core, 19 permanent magnet, 21 magnet insertion hole, 53 hole inner line, 55 hole outer line, 57 hole side line, 61 recess, 260 rotary compressor, 261 closed container, 380 refrigeration air conditioner.

Claims

In an embedded permanent magnet electric motor comprising a rotor having a plurality of permanent magnets and a stator,
The rotor includes a rotor core;
The rotor iron core has a plurality of magnet insertion holes,
Each of the permanent magnets is inserted into the magnet insertion hole,
Each of the magnet insertion holes is formed in a convex shape toward the center side of the rotor,
Each of the magnet insertion holes has a hole inner line, a hole outer line, and a pair of hole side lines,
Each of the hole outer lines includes a pair of recesses at the end,
The depth of the recess is 10 to 40% of the thickness of the permanent magnet.
Permanent magnet embedded motor.
In the state where the permanent magnet is inserted into the magnet insertion hole, a gap is generated between the concave portion and the permanent magnet.
The embedded permanent magnet electric motor according to claim 1.
The permanent magnet is a ferrite magnet or a rare earth magnet,
The embedded permanent magnet electric motor according to any one of claims 1 to 2.
A compressor having an electric motor and a compression element in a sealed container,
The electric motor is an embedded permanent magnet electric motor according to any one of claims 1 to 3.
Compressor.
A refrigeration air conditioner comprising the compressor of claim 4 as a component of a refrigeration circuit.