Permanent magnet embedded electric motor, compressor, and refrigerating and air-conditioning device

An interior permanent magnet motor includes a stator and a rotor. The rotor includes a rotor core formed by laminating a plurality of plate members. The rotor core has a plurality of magnet insertion holes formed therein, into which corresponding permanent magnets are respectively inserted. At least one slit and at least one caulked portion are formed between a rotor outer peripheral surface of the rotor and a radially-outer insertion hole contour surface of the magnet insertion hole. At least a part of the caulked portion is positioned between a pair of width extended lines of the slit.

CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage application of PCT/JP2014/074635 filed on Sep. 18, 2014, which claims priority to International Application No. PCT/JP2013/076116 filed on Sep. 26, 2013, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an interior permanent magnet motor, a compressor, and a refrigeration and air conditioning apparatus.

BACKGROUND ART

As a related-art interior permanent magnet motor, in Patent Literature 1, there is disclosed an interior permanent magnet motor in which a plurality of slits are formed on a radially outer side of a rotor with respect to magnet insertion holes. In the interior permanent magnet motor, a harmonic component of a magnetic-flux density waveform is reduced due to a function of the slit so that a harmonic of an inducted voltage and a clogging torque are reduced, thereby being capable of reducing noise and vibration.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

On the other hand, the rotor of the interior permanent magnet motor is formed by laminating thin magnetic steel plates. Therefore, caulked portions are required to be formed so as to fix the steel plates. Further, when the caulked portions are positioned on the radially outer side of the rotor, the steel plates can be more effectively fixed.

The present invention has been made in view of the above, and has an object to provide an interior permanent magnet motor capable of fixing plate members at caulked portions more effectively and reducing noise and vibration.

Solution to Problem

In order to achieve the above-mentioned object, according to one embodiment of the present invention, there is provided an interior permanent magnet motor, including: a stator; and a rotor rotatably arranged so as to be opposed to the stator, in which the rotor includes a rotor core formed by laminating a plurality of plate members, in which the rotor core has a plurality of magnet insertion holes formed therein, into which corresponding permanent magnets are respectively inserted, in which the plurality of magnet insertion holes are each formed into a shape that is convex toward a center side of the rotor, in which at least one slit and at least one caulked portion are formed between a rotor outer peripheral surface of the rotor and a radially-outer insertion hole contour surface of the magnet insertion hole, and in which at least a part of the caulked portion is positioned between a pair of width extended lines of the slit.

The plurality of magnet insertion holes may each be formed into a shape that is convex toward a center side of the rotor.

The entire caulked portion may be positioned between the pair of width extended lines of the slit.

A plurality of the slits may be formed between the rotor outer peripheral surface of the rotor and the radially-outer insertion hole contour surface of the magnet insertion hole, and the plurality of the slits may be arrayed in a width direction.

The caulked portion may be formed on a radially inner side with respect to the corresponding slit.

Further, in order to achieve the same object, according to one embodiment of the present invention, there is also provided a compressor. The compressor of the one embodiment of the present invention includes, in an airtight container: a motor; and a compression element. The motor is the above-mentioned interior permanent magnet motor of the one embodiment of the present invention.

Further, in order to achieve the same object, according to one embodiment of the present invention, there is also provided a refrigeration and air conditioning apparatus. The refrigeration and air conditioning apparatus of the one embodiment of the present invention includes the above-mentioned compressor of the one embodiment of the present invention as a component of a refrigeration cycle.

Advantageous Effects of Invention

According to the one embodiment of the present invention, it is possible to fix the plate members at the caulked portions more effectively and reduce noise and vibration.

DESCRIPTION OF EMBODIMENTS

Now, embodiments of the present invention are described referring to the accompanying drawings. Note that, in the drawings, the same reference symbols represent the same or corresponding parts. Note that, inFIG. 2toFIG. 5,FIG. 7toFIG. 11, andFIG. 14toFIG. 21, for the sake of clarity of illustration, the hatching is omitted.

First Embodiment

FIG. 1is a view for illustrating a cross-section orthogonal to a rotation center line of an interior permanent magnet motor according to a first embodiment of the present invention.FIG. 2is a view for illustrating a peripheral part of one permanent magnet ofFIG. 1in an enlarged manner.FIG. 3is a view for illustrating a periphery of a plurality of slits ofFIG. 2in a further enlarged manner.

An interior permanent magnet motor1includes a stator3and a rotor5rotatably arranged so as to be opposed to the stator. The stator3includes a plurality of tooth portions7. Each of the plurality of tooth portions7is adjacent to other tooth portions7through intermediation of corresponding slot portions9. The plurality of tooth portions7and a plurality of the slot portions9are arranged alternately at equal intervals in a circumferential direction. A publicly known stator winding (not shown) is wound around each of the plurality of tooth portions7in a publicly known manner.

The rotor5includes a rotor core11and a shaft13. The shaft13is coupled to an axial center portion of the rotor core11by shrink fitting, press fitting, or the like to transmit rotational energy to the rotor core11. An air gap15is secured between an outer peripheral surface of the rotor5and an inner peripheral surface of the stator3.

In such a configuration, the rotor5is held on an inner side of the stator3through intermediation of the air gap15so as to be rotatable about a rotation center line CL (rotation center of the rotor, axial line of the shaft). Specifically, a current having a frequency synchronized with an instructed number of revolutions is supplied to the stator3to generate a rotation magnetic field, thereby rotating the rotor5. The air gap15between the stator3and the rotor5is, for example, an air gap of from 0.3 mm to 1 mm.

Next, configurations of the stator3and the rotor5are described in detail. The stator3includes a stator core17. The stator core17is formed by, for example, punching magnetic steel plates each having a thickness of from about 0.1 mm to about 0.7 mm into a predetermined shape, and laminating a predetermined number of the magnetic steel plates while fastening the magnetic steel plates at caulked portions. In this case, as an example, the magnetic steel plates each having a thickness of 0.35 mm are used.

The stator core17has nine slot portions9radially formed on a radially inner side thereof at substantially equal intervals in the circumferential direction. Further, a region between the adjacent slot portions9in the stator core17is referred to as the tooth portion7. Each of the tooth portions7extends in a radial direction, and protrudes toward the rotation center line CL. Further, a most pare of the tooth portion7has a substantially constant width in the circumferential direction over a range from a radially outer side to a radially inner side. However, a distal end portion of the tooth portion7, which is located on the radially innermost side, has a tooth tip portion7a.Each tooth tip portion7ais formed into an umbrella shape with its both side portions expanding in the circumferential direction.

The stator winding (not shown) forming a coil (not shown) configured to generate a rotational magnetic field is wound around the tooth portion. The coil is formed by directly winding a magnet wire around the magnetic pole tooth through intermediation of an insulator. This winding method is referred to as a concentrated winding. The coil is connected in three-phase Y connection. The number of turns and a wire diameter of the coil are determined depending on required characteristics (number of revolutions, torque, and the like), the voltage specifications, and the sectional area of the slot. In this case, in order to facilitate the winding, separated teeth are developed in a band shape, and, for example, a magnet wire having a wire diameter φ of from about 0.8 mm to about 1.0 mm is wound around each of the magnetic pole teeth by about 50 turns to about 100 turns. After the winding, the separated teeth are rounded into an annular shape and welded, to thereby form the stator.

The rotatably held shaft13is arranged in the vicinity of a center of the stator3. Further, the rotor5is fitted onto the shaft13. The rotor5includes the rotor core11, and similarly to the stator core17, the rotor core11is also formed by, for example, punching magnetic steel plates each having a thickness of from about 0.1 mm to about 0.7 mm into a predetermined shape, and laminating a predetermined number of the magnetic steel plates serving as plate members while fastening the magnetic steel plates at caulked portions to be described later. In this case, as an example, the magnetic steel plates each having a thickness of 0.35 mm are used. Inter-pole thin portions having a uniform thickness are each secured between a rotor outer peripheral surface25and a side-end insertion hole contour surface57described later. Those inter-pole thin portions each serve as a path for a leakage magnetic flux between the adjacent magnetic poles, and hence it is preferred that the inter-pole thin portion have a thickness as small as possible. In this case, as an example, the inter-pole thin portion is set to 0.35 mm, which is approximately as large as the thickness of the magnetic steel plate, as the minimum width that allows press work.

A plurality of permanent magnets19(six permanent magnets19in this specific example), which are magnetized so that the N poles and the S poles are alternately positioned, are arranged in the rotor core11. Referring toFIG. 1, each of the permanent magnets19is curved into an arc shape and arranged so that a convex portion side of the arc shape faces the center side of the rotor5. In more detail, magnet insertion holes21as many as the number of the plurality of permanent magnets19are formed in the rotor core11. The corresponding permanent magnets19are inserted into a plurality of the magnet insertion holes21, respectively. That is, the plurality of permanent magnets19and the plurality of magnet insertion holes21are each formed into an arc shape that is convex toward the center side of the rotor5. Further, as illustrated inFIG. 1, one permanent magnet19is inserted into one magnet insertion hole21. Note that, the number of magnetic poles of the rotor5may be any number as long as the number is two or more. The case of six poles is exemplified in this embodiment.

In the present invention, at least one slit and at least one caulked portion are required to be formed between the rotor outer peripheral surface of the rotor and a radially-outer insertion hole contour surface of the magnet insertion hole, which is described later. In the first embodiment, as one example thereof, a plurality of (more specifically, three) slits72and one caulked portion76are formed for each of six magnetic poles.

Next, mainly referring toFIG. 2, details of the permanent magnets and the magnet insertion holes are described. The permanent magnets19each have a radially-inner magnet contour surface43, a radially-outer magnet contour surface45, and a pair of side-end magnet contour surfaces47. Further, the magnet insertion holes21each have a radially-inner insertion hole contour surface53, a radially-outer insertion hole contour surface55, and a pair of side-end insertion hole contour surfaces57.

The radially-outer insertion hole contour surface55is formed by a first arc surface having a first arc radius. The radially-inner insertion hole contour surface53is formed by a second arc surface having a second arc radius larger than the first arc radius. The first arc radius and the second arc radius have a common radius center, and the common radius center is located on the radially outer side with respect to the permanent magnet19and the magnet insertion hole21and on a corresponding magnetic pole center line ML. In other words, the radially-inner insertion hole contour surface53and the radially-outer insertion hole contour surface55are formed concentrically. The center of the first arc surface and the center of the second arc surface coincide with an orientation, center (orientation focal point) of the permanent magnet.

Further, inFIG. 2, the pair of side-end magnet contour surfaces47each connect together corresponding end portions of the radially-inner magnet contour surface43and the radially-outer magnet contour surface45. InFIG. 2, the pair of side-end insertion hole contour surfaces57each connect together corresponding end portions of the radially-inner insertion hole contour surface53and the radially-outer insertion hole contour surface55.

Further, referring toFIG. 2andFIG. 3, details of the slits and the caulked portion are described. The slits72all extend in a direction parallel to the corresponding magnetic pole center line ML. The slits72are holes passing through the rotor core11in a direction of the rotation center line CL. Assuming that a direction orthogonal to the corresponding magnetic pole center line ML is defined as a width direction WD, and a width of one slit72corresponding to the caulked portion76(slit72ain alignment with a caulked portion) is defined as SW, in the present invention, at least a part of the caulked portion76is positioned between a pair of width extended lines WE of the slit72corresponding to the caulked portion76. Further, the state in which at least the part of the caulked portion76is positioned (including a state in which a part of the caulked portion76is positioned and a state in which the entire caulked portion76is positioned) between the pair of width extended lines WE of the slit72corresponding to the caulked portion76as described above is defined as a state in which the slit72and the caulked portion76are “in alignment” in the radial direction. In particular, in the first embodiment, the entire caulked portion76is positioned between the pair of width extended lines of the corresponding one slit72(slit72ain alignment with a caulked portion).

In the first embodiment, slits72(independent slits72b) not in alignment with the caulked portion76are positioned on both sides of the slit72ain alignment with a caulked portion in the width direction WD. The three slits72are separated from each other at equal intervals in the width direction WD. Further, a length of extension of one slit72ain alignment with a caulked portion is smaller than a length of extension of each of the two independent slits72b.Further, a width of the caulked portion76is smaller than a width of the slit72ain alignment with a caulked portion. Further, a positional relationship between the slit72ain alignment with a caulked portion and the caulked portion76in an extending direction of the corresponding magnetic pole center line ML is such that the caulked portion76is formed on the radially inner side with respect to the slit72ain alignment with a caulked portion. A center line of the slit72ain alignment with a caulked portion in the width direction and a center line of the caulked portion76in the width direction are aligned on the same line. In addition, the three slits72and the one caulked portion76are arranged to be line symmetric with respect to the corresponding magnetic pole center line ML as the center.

According to the interior permanent magnet motor of the first embodiment, which is constructed as described above, the following advantages are obtained. First, inFIG. 4, a rotor without slits is illustrated. In such a rotor without slits, when a magnetic flux is generated in the stator, due to the magnetic flux of the stator, an attraction force acts in portions of the core of the rotor on the radially outer side with respect to the magnet insertion holes. This force causes vibration and noise. Thus, it is desired to reduce the attraction force acting in the vicinity of the outer peripheral surface of the rotor to the extent possible.

In view of the above, as illustrated inFIG. 5, it is effective to form slits78in each of the portions of the core of the rotor on the radially outer side with respect to the magnet insertion holes. The attraction force is not generated in portions corresponding to the slits78, and hence the attraction force acting during the rotation of the rotor is reduced. As a result, noise and vibration can be reduced.

InFIG. 6, a result of analyzing electromagnetic forces (fundamental components) (which may cause noise) generated when driving the rotor illustrated inFIG. 4and the rotor illustrated inFIG. 5under the same operation condition is shown. Assuming that the electromagnetic force in the rotor without slits illustrated inFIG. 4is 100%, as understood from the result, the electromagnetic force in the rotor with the slits illustrated inFIG. 5is about 40%. It is understood that noise is reduced by additionally forming the slits. In this case, in order to further reduce noise, it is desired to enlarge the slits. However, as indicated by the arrows ofFIG. 7, the magnetic flux of the magnet inserted into the rotor illustrated inFIG. 5passes through portions other than the slits. When the slits are enlarged, a width of portions serving as magnetic paths is reduced accordingly, which causes reduction of the magnetic force of the rotor, thus leading, to degradation of the efficiency. Therefore, it is important to keep such a balance that the slits are formed in a level that may not reduce the magnetic force of the rotor.

However, on the other hand, in order to more effectively fix members constructing the rotor, the arrangement of the caulked portion is required to be considered. When the caulked portion is formed on the radially outer side of the rotor, opening of the core is more effectively suppressed. Therefore, when a caulked portion79is to be formed in the rotor illustrated inFIG. 5from this viewpoint, the caulked portion79is naturally formed between the slits78as illustrated inFIG. 8.

However, when the caulked portion79is formed between the pair of slits78as illustrated inFIG. 8, the magnetic force is undesirably reduced.

In view of the above, in the present invention, as illustrated inFIG. 9, at least the part of the caulked portion76is positioned between the pair of width extended lines WE of the slit72. In other words, a state illustrated inFIG. 10, in which the entire caulked portion is not positioned between the pair of width extended lines of the slit, is avoided. In the first embodiment, as one mode thereof, as illustrated inFIG. 3, the entire caulked portion76is positioned between the pair of width extended lines WE of the slit72. With this, the reduction of the magnetic force can be suppressed in accordance with the area of a portion of the caulked portion, which is positioned in the range of the width of the slit. In particular, in the first embodiment having the configuration illustrated inFIG. 3, the caulked portion76can be formed on the radially outer side with respect to the magnet insertion hole21without occupying the magnetic path between the adjacent slits72. Therefore, the plate members constructing the rotor can be fixed more effectively at the caulked portions, and noise and vibration can be reduced.

Further, as one mode of the present invention in which at least the part of the caulked portion76is positioned between the pair of width extended lines WE of the slit72, there is given a mode in which the caulked portion76is formed on the radially outer side with respect to the corresponding slit72as illustrated inFIG. 11. On the other hand, in the first embodiment, as illustrated inFIG. 3, the caulked portion76is formed on the radially outer side with respect to the corresponding slit72. Both the modes illustrated inFIG. 3andFIG. 11have an advantage of being capable of reducing noise and vibration as well as being capable of more effectively fixing the plate members constructing the rotor at the caulked portions. Further, the first embodiment illustrated inFIG. 3has an advantage over the mode inFIG. 11.

FIG. 12andFIG. 13are illustrations of a cross-section taken along the line I-I ofFIG. 3and a cross-section taken along the line II-II ofFIG. 11, respectively. The caulked portion76of laminated steel sheets can maintain the laminated state by being press-fitted, and stresses act due to the press fitting. Therefore, in the mode in which the caulked portion76is formed on the radially outer side with respect to the slit72, caution is required to be taken so as to prevent slight increase of the outer diameter of the rotor due to stresses F acting in a direction of the radially outer side, which are indicated by the arrows illustrated inFIG. 13. On the other hand, in the mode in which the caulked portion76is formed on the radially inner side with respect to the slit72as in the first embodiment, stresses F acting in the direction. of the radially outer side, which are indicated by the arrows ofFIG. 12, are hardly propagated. to the vicinity of the rotor outer peripheral surface25of the rotor due to the presence of the slit72(slit72ain alignment with a caulked portion). Therefore, with the structure itself, an effect of suppressing bulge of the rotor outer peripheral surface, which may be caused due to the press fitting at the caulked portions, can be expected.

Second Embodiment

A second embodiment of the present invention is described. As the second embodiment of the present invention, there is given, for example, as illustrated inFIG. 9, a mode in which at least the part of the caulked portion is positioned between the pair of width extended lines of the slit. Note that, other configurations of the second embodiment are the same as those of the first embodiment.

Third Embodiment

A third embodiment of the present invention is described. As the third embodiment of the present invention, there is given, for example, as illustrated inFIG. 11andFIG. 13, a mode in which the caulked portion is formed on the radially outer side with respect to the corresponding slit. Note that, other configurations of the third embodiment are the same as those of the first or second embodiment.

Fourth Embodiment

Next, a fourth embodiment of the present invention is described. The present invention is not limited to the mode in which the caulked portion is located on the magnetic pole center line ML or the mode in which the caulked portion and the slit in alignment with a caulked portion are interposed between a pair of the independent slits. The present invention may be carried out in a mode in which the caulked portion is not located on the magnetic pole center line ML or a mode in which the independent slits are not formed on both sides in the width direction of the caulked portion and the slit in alignment with a caulked portion.FIG. 14andFIG. 15are each an example thereof, in which a slit172(independent slit172b) is located on the magnetic pole center line ML, and a pair of caulked portions176and a pair of slits172(slits72ain alignment with caulked portions) are formed to be positioned on both sides of the slit172(independent slit172b) in the width direction. Note that, other configurations of the fourth embodiment are the same as those of the first or second embodiment. According to the fourth embodiment, advantages similar to the above-mentioned first or second embodiment are obtained. In addition, the caulked portions are formed on both the sides of each magnetic pole center line ML, and hence the fourth embodiment has an advantage in obtaining an effect of suppressing the opening of the core to a higher degree.

Fifth Embodiment

Next, a fifth embodiment of the present invention is described. In the present invention, the plurality of caulked portions176may be provided for one magnetic pole as in the above-mentioned fourth embodiment. In this case, the caulked portions176are not limited to be each positioned on the radially inner side with respect to a corresponding slit172ain alignment with a caulked portion.FIG. 16andFIG. 17are each an example thereof, specifically, a mode in which the positional relationship of the radially inner and outer sides is switched between the caulked portions176and the slits172(slits172ain a with caulked portions) in the above-mentioned fourth embodiment. Note that, other configurations of the fifth embodiment are the same as those of the fourth embodiment. According to the fifth embodiment, advantages similar to the above-mentioned first or second embodiment are obtained. In addition, the caulked portions are formed on both the sides of each magnetic pole center line ML as in the fourth embodiment, and hence the fifth embodiment has an advantage in obtaining the effect of suppressing the opening of the core to a higher degree. Further, in the fifth embodiment, the caulked portions located on both the sides of each magnetic pole center line ML are arranged on an outer side in the radial direction so that a force for holding the laminated steel sheets is further increased. Thus, more significant quality improvement can be expected.

Sixth Embodiment

Next, a sixth embodiment of the present invention is described. The present invention may be carried out in a mode in which both the center of the caulked portion in the width direction and the center of the slit in alignment with a caulked portion in the width direction are displaced from the magnetic pole center line ML, and the independent slit72bis positioned on the magnetic pole center line ML.FIG. 18andFIG. 19are each an example thereof. A slit272(independent slit172b) is located on the magnetic pole center line ML. A slit272(independent slit72b) is located on one side thereof in the width direction, and a slit272(slit172ain alignment with a caulked portion) and a caulked portion276are located on the other side. Note that, other configurations of the sixth embodiment are the same as those of the first or second embodiment. According to the sixth embodiment, advantages similar to the above-mentioned first or second embodiment are obtained.

Seventh Embodiment

Next, a seventh embodiment of the present invention is described. The seventh embodiment corresponds to a mode in which the positional relationship of the radially inner and outer sides is switched between the caulked portion276and the slit272(slit172ain alignment with a caulked portion) in the above-mentioned sixth embodiment as illustrated inFIG. 20andFIG. 21. Note that, other configurations of the seventh embodiment are the same as those of the sixth embodiment. According to the seventh embodiment, advantages similar to the above-mentioned first or second embodiment are obtained.

Eighth Embodiment

An eighth embodiment of the present invention is described. In the eighth embodiment of the present invention, in place of the above-mentioned permanent magnets and magnet insertion holes each having the shape that is convex toward the center side of the rotor, there are provided, for example, as illustrated inFIG. 22, permanent magnets319and magnet insertion holes321each extending straight when viewed in the cross-section having the rotation center line CL as the normal. In particular, in the illustrated example ofFIG. 22, when viewed in the cross-section having the rotation center line CL as the normal, a radially-inner magnet contour surface and a radially-outer magnet contour surface of the permanent magnet319and a radially-inner insertion hole contour surface and a radially-outer insertion hole contour surface of the magnet insertion hole321extend straight in the direction orthogonal to the corresponding magnetic pole center line ML (width direction WD described above). Further, when viewed in the cross-section having the rotation center line CL as the normal, the radially-inner magnet contour surface and the radially-outer magnet contour surface of the permanent magnet319extend in parallel to each other, and the radially-inner insertion hole contour surface and the radially-outer insertion hole contour surface of the magnet insertion hole321extend in parallel to each other. Note that, other configurations of the eighth embodiment are the same as those of the first embodiment. Further, similarly to the above-mentioned second embodiment, the eighth embodiment may be modified such that at least the part of the caulked portion is positioned between the pair of width extended lines of the slit.

Ninth Embodiment

A ninth embodiment of the present invention is described. In the ninth embodiment of the present invention, for example, as illustrated inFIG. 23, the permanent magnet319and the magnet insertion hole321each extending straight are provided, and the caulked portion76is formed on the radially outer side with respect to the corresponding slit72. Note that, other configurations of the third embodiment are the same as those of the first or second embodiment.

Tenth Embodiment

Next, a tenth embodiment of the present invention is described. In the tenth embodiment of the present invention, for example, as illustrated inFIG. 24, the permanent magnet319and the magnet insertion hole321each extending straight are provided. The slit172(independent slit172b) is located on the magnetic pole center line ML, and the pair of caulked portion176and a pair of the slits172(slits72ain alignment with caulked portions) are formed to be positioned. on both sides of the slit172(independent slit172b) in the width direction. Note that, other configurations of the tenth embodiment are the same as those of the first or second embodiment. According to the tenth embodiment, similarly to the above-mentioned fourth embodiment, the caulked portions are formed on both the sides or each magnetic pole center line ML, and hence the tenth embodiment has an advantage in obtaining an effect. of suppressing the opening of the core to a higher degree.

Eleventh Embodiment

Next, an eleventh embodiment of the present invention is described. In the eleventh embodiment of the present invention, for example, as illustrated inFIG. 25, the permanent magnet319and the magnet insertion hole321each extending straight are provided. Further, the eleventh embodiment corresponds to a mode in which the positional relationship of the radially inner and outer sides is switched between the caulked portions176and the slits172(slits172ain alignment, with caulked portions) from the above-mentioned tenth embodiment. Note that, other configurations of the eleventh embodiment are the same as those of the tenth embodiment. According to the eleventh embodiment, advantages similar to the above-mentioned first or second embodiment are obtained. In addition, the caulked portions are formed on both the sides of each magnetic pole center line ML as in the tenth embodiment, and hence the eleventh embodiment has an advantage in obtaining the effect of suppressing the opening of the core to a higher degree. Further, in the eleventh embodiment, the caulked portions located on both the sides of each magnetic pole center line ML are arranged on the outer side in the radial direction so that the force for holding the laminated steel sheets is further increased. Thus, more significant quality improvement can be expected.

Twelfth Embodiment

Next, a twelfth embodiment of the present invention is described. In the twelfth embodiment of the present invention, for example, as illustrated inFIG. 26, the permanent magnet319and the magnet insertion hole321each extending straight are provided. The slit272(independent slit172b) is located on the magnetic pole center line ML. The slit272(independent, slit72b) is located on one side thereof in the width direction, and the slit272(slit172ain alignment with a caulked portion) and the caulked portion276are located on the other side. Note that, other configurations of the twelfth embodiment are the same as those of the first or second embodiment. According to the twelfth embodiment, advantages similar to the above-mentioned first or second embodiment are obtained.

Thirteenth Embodiment

Next, a thirteenth embodiment of the present invention is described. In the thirteenth embodiment of the present invention, for example, as illustrated inFIG. 27, the permanent magnet319and the magnet insertion hole321each extending straight are provided. Further, the thirteenth embodiment corresponds to a mode in which the positional relationship of the radially inner and outer sides is switched between the caulked portion276and the slit272(slit172ain alignment with a caulked portion) from the above-mentioned twelfth embodiment. Note that, other configurations of the thirteenth embodiment are the same as those of the twelfth embodiment. According to the thirteenth embodiment, advantages similar to the above-mentioned first or second embodiment are obtained.

Fourteenth Embodiment

Next, as a fourteenth embodiment of the present invention, there is described a rotary compressor having the interior permanent magnet motor according to any one of the above-mentioned first to thirteenth embodiments mounted therein. Note that, the present invention encompasses a compressor having the interior permanent magnet motor according to any one of the above-mentioned first to thirteenth embodiments mounted therein. However, the type of the compressor is not limited to the rotary compressor.

FIG. 28is a vertical sectional view of the rotary compressor having the interior permanent magnet motor mounted therein. A rotary compressor100includes the interior permanent magnet motor1(motor element) and a compression element103in an airtight container101. Although not illustrated, a refrigerating machine oil for lubricating each of sliding portions of the compression element103is stored in a bottom portion of the airtight container101.

The compression element103includes, as main components thereof, a cylinder105arranged in a vertically stacked state, a rotary shaft107serving as a shaft rotated by the interior permanent magnet motor1, a piston109to be fitted by insertion into the rotary shaft107, a vane (not shown) dividing an inside of the cylinder105into an intake side and a compression side, an upper frame111and a lower frame113being a pair of upper and lower frames into which the rotary shaft107is to be rotatably fitted by insertion and which are configured to close axial end surfaces of the cylinder105, and mufflers115mounted on the upper frame111and the lower frame113, respectively.

The stator3of the interior permanent magnet motor1is directly fixed to the airtight container101by a method such as shrink fitting or welding and is held thereby. The coil of the stator3is supplied with power from a glass terminal fixed to the airtight container101.

The rotor5is arranged through intermediation of an air gap on the radially inner side of the stator3, and is held in a rotatable state by the bearing portions (upper frame111and lower frame113) of the compression element103via the rotary shaft107(shaft13) in the center portion of the rotor5.

Next, an operation of the rotary compressor100is described. A refrigerant gas supplied from an accumulator117is taken into the cylinder105through an intake pipe119fixed to the airtight container101. The interior permanent magnet motor is rotated by energization of an inverter so that the piston109fitted to the rotary shaft107is rotated in the cylinder105. With this, the refrigerant is compressed in the cylinder105. The refrigerant, which has passed through the muffler115, rises in the airtight container101. At this time, the refrigerating machine oil is mixed into the compressed refrigerant. When the mixture of the refrigerant and the refrigerating machine oil passes through air holes formed in the rotor core11, the refrigerant and the refrigerating machine oil are promoted to be separated from each other, and hence the refrigerating machine oil can be prevented from flowing into a discharge pipe121. In this manner, the compressed refrigerant is supplied on a high-pressure side of the refrigeration cycle through the discharge pipe121arranged on the airtight container101.

Note that, as the refrigerant for the rotary compressor100, R410A, R407C, R22, or the like that has hitherto been used may be used, but any refrigerant such as a refrigerant having a low global warming potential (GWP) can also be applied. In view of the prevention of global warming, a low GWP refrigerant is desirable. As typical examples of the low GWP refrigerant, the following refrigerants are given.

(1) A halogenated hydrocarbon having a carbon double bond in the composition; for example, HFO-1234yf (CF3CF═CH2) is given. An HFO is an abbreviation of a Hydro-Fluoro-Olefin, and an Olefin is an unsaturated hydrocarbon having one double bond. Note that, a GWP of HFO-1234yf is 4.

(2) A hydrocarbon having a carbon double bond in the composition; for example, R1270 (propylene) is given. Note that, R1270 has a GWP of 3, which is smaller than that of HFO-1234yf, but has higher combustibility than HFO-1234yf.

(3) A mixture containing at least any 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 given. HFO-1234yf, which is a low pressure refrigerant, is large in pressure loss and is thus liable to degrade the performance of the refrigeration cycle (in particular, in an evaporator). Therefore, a mixture of HFO-1234yf and R32 or R41 that is a refrigerant higher in pressure than HFO-1234yf is positively used in practical.

Also in the rotary compressor according to the fourteenth embodiment, which is constructed as described above, when the above-mentioned interior permanent magnet motor is used, advantages similar to the advantages of any one of the corresponding first to thirteenth embodiments described above are obtained.

Fifteenth Embodiment

Further, the present invention may be carried out as a refrigeration and air conditioning apparatus including the compressor according to the above-mentioned fourteenth embodiment as a component of a refrigeration cycle. Note that, configurations of components other than the compressor of the refrigeration cycle of the refrigeration and air conditioning apparatus are not particularly limited.

In the above, the details of the present invention are specifically described referring to the preferred embodiments. However, it is apparent to those skilled in the art that various modifications may be made based on the basic technical concept and the teachings of the present invention.

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