JP2011083168A - Rotor of permanent magnet embedded motor, blower and compressor - Google Patents

Abstract

An object of the present invention is to provide a rotor of a permanent magnet embedded motor capable of reducing magnetic saturation caused by a slit arranged in an outer peripheral iron core of a permanent magnet insertion hole, further reducing the influence of armature reaction, and reducing torque ripple. To do.
A rotor of a permanent magnet embedded motor according to the present invention includes a plurality of permanent magnet insertion holes 122 formed along an outer peripheral portion of a rotor core 121, and both end portions of the permanent magnet insertion holes 122. Permanent magnet end gap 124 provided, permanent magnet inserted into permanent magnet insertion hole 122, a plurality of slits 125a to 125e formed in the iron core portion outside permanent magnet insertion hole 122, and a plurality of slits 125a to 125a. The radial dimension of the slit thin portions 126 a to 126 e between the rotor core 121 and the outer peripheral portion 121 a of 125 e is set to the permanent magnet between the permanent magnet end gap 124 and the outer peripheral portion 121 a of the rotor core 121. This is larger than the radial dimension of the end thin portion 124a.
[Selection] Figure 14

Description

  The present invention relates to a rotor of a permanent magnet embedded motor, and more particularly to a slit shape disposed in an outer peripheral core portion of a permanent magnet insertion hole. The present invention also relates to a blower and a compressor that use the rotor of the permanent magnet embedded motor for the permanent magnet embedded motor.

  Conventionally, a rotor of a permanent magnet embedded motor having the following configuration has been proposed. In other words, the rotor of this permanent magnet embedded motor is composed of a rotor core formed by laminating a plurality of electromagnetic steel sheets, and a substantially positive shape formed in the axial direction of the rotor core and centered on the axis. Permanent magnet insertion holes formed at portions corresponding to each side of the polygon, permanent magnets inserted into the permanent magnet insertion holes, and formed on the outer peripheral iron core of the permanent magnet insertion holes, along the permanent magnet insertion holes A plurality of slits that are spaced apart from each other, and an outer side that is provided between the radially outer end of the slit and the outer periphery of the rotor core, and whose radial width gradually increases from the center of the magnetic pole toward the interpole. And a thin-walled portion. By configuring in this way, the harmonic component of the magnetic flux density waveform at the inter-electrode portion can be reduced to reduce the harmonics of the induced voltage and the cogging torque (see, for example, Patent Document 1).

JP 2008-167583 A

  The slit shape of the rotor of the conventional permanent magnet embedded motor described in Patent Document 1 described above is gradually increased as the width of the thin wall between the slit and the outer periphery of the rotor approaches the gap portion, and the induced voltage is increased. Harmonic was reduced.

  However, there is a demand for further improving torque ripple and noise by reducing harmonics of the induced voltage.

  The present invention has been made to solve the above-described problems, and reduces magnetic saturation caused by a slit disposed in the outer peripheral core portion of the permanent magnet insertion hole, further reduces the effect of armature reaction, and reduces torque. Provided is a rotor for a permanent magnet embedded motor capable of reducing ripple.

  Moreover, the air blower and compressor which use the rotor of the permanent magnet embedded motor for a permanent magnet embedded motor are provided.

The rotor of the permanent magnet embedded motor according to the present invention includes a rotor core formed by laminating a predetermined number of electromagnetic steel sheets punched into a predetermined shape,
A plurality of permanent magnet insertion holes formed along the outer periphery of the rotor core;
Permanent magnet end gaps provided at both ends of the permanent magnet insertion hole;
A permanent magnet inserted into the permanent magnet insertion hole;
A plurality of slits formed in the iron core outside the permanent magnet insertion hole;
The radial dimension of the slit thin portion between each of the plurality of slits and the outer periphery of the rotor core is the radial dimension of the thin portion of the permanent magnet end between the gap between the permanent magnet end portion and the outer periphery of the rotor core. It is larger than the dimensions.

  In the rotor of the permanent magnet embedded motor according to the present invention, the radial dimension between each of the plurality of slits and the outer periphery of the rotor core is determined between the gap between the end of the permanent magnet and the outer periphery of the rotor core. By making it larger than the radial dimension of the permanent magnet end thin portion, the magnetic saturation of the slit thin portion can be relaxed, and the torque ripple can be reduced.

It is a figure shown for a comparison and is a cross-sectional view of a general permanent magnet embedded motor 500. FIG. 2 is a cross-sectional view of the rotor 520 in FIG. 1. FIG. 5 is a cross-sectional view of the rotor core 521 in FIG. 2. A cross-sectional view of a general permanent magnet embedded motor 600 having a slit, which is shown for comparison. FIG. 6 is a cross-sectional view of the rotor 620 in FIG. 4. FIG. 6 is a cross-sectional view of the rotor core 621 in FIG. 5. The elements on larger scale of FIG. The figure which compared the torque of the permanent magnet embedded type motor 500 (without a slit) and the permanent magnet embedded type motor 600 (with a slit). FIG. 3 shows the first embodiment and is a cross-sectional view of the permanent magnet embedded motor 100. FIG. 10 is a cross-sectional view of the rotor 120 of FIG. 9. FIG. 11 is a cross-sectional view of the rotor core 121 of FIG. 10. The elements on larger scale of FIG. The elements on larger scale of FIG. The elements on larger scale of FIG. The figure which shows Embodiment 1 and shows the torque waveform when the dimension of a slit thin part is uniform, and the relationship between a slit thin part is t1 <t2 <t6 <t3 <t4 <t5. FIG. 5 shows the first embodiment, and is a transverse cross-sectional view of a modified permanent magnet embedded motor 200. FIG. 17 is a cross-sectional view of the rotor 220 in FIG. 16. FIG. 18 is a cross-sectional view of the rotor core 121 of FIG. 17. The elements on larger scale of FIG. The elements on larger scale of FIG. The elements on larger scale of FIG.

Embodiment 1 FIG.
1 to 8 are diagrams for comparison, FIG. 1 is a cross-sectional view of a general permanent magnet embedded motor 500, FIG. 2 is a cross-sectional view of the rotor 520 of FIG. 1, and FIG. 4 is a cross-sectional view of a general embedded permanent magnet motor 600 having a slit, FIG. 5 is a cross-sectional view of the rotor 620 of FIG. 4, and FIG. FIG. 7 is a partially enlarged view of FIG. 6, and FIG. 8 is a torque of a permanent magnet embedded motor 500 (without slit) and a permanent magnet embedded motor 600 (with slit). FIG.

  First, a general permanent magnet embedded motor will be described. A permanent magnet embedded motor 500 shown in FIG. 1 includes at least a stator 510 and a rotor 520.

  Stator 510 includes at least a stator core 511 and a winding 514.

  The stator core 511 is a thin electromagnetic steel plate (for example, a thickness of about 0.1 to 1.0 mm, a non-oriented electrical steel plate (the crystal axis of each crystal so as not to be biased toward a specific direction of the steel plate and exhibit magnetic properties). The direction is randomly arranged as much as possible))) is punched into a predetermined shape with a mold, and a predetermined number (a plurality) are laminated.

  The stator core 511 has a substantially cylindrical cross-sectional shape as a whole, and includes a ring-shaped core back 515 on the outer peripheral side. Eighteen teeth 512 extend radially inward from the ring-shaped core back 515 at substantially equal intervals. Between two adjacent teeth 512, a slot 513 (18 pieces) in which the winding 514 is accommodated is formed.

  The rotor 520 includes at least a rotor core 521 and a permanent magnet 523.

  The rotor core 521 has a substantially circular cross-sectional shape as a whole, a thin electromagnetic steel plate (for example, a thickness of about 0.1 to 1.0 mm, and a non-oriented electrical steel plate (biased in a specific direction of the steel plate). The crystal axis direction of each crystal is arranged as randomly as possible so as not to exhibit magnetic properties))) is punched with a mold into a predetermined shape, and a predetermined number (multiple) is laminated.

  The rotor core 521 is formed with six permanent magnet insertion holes 522 having a rectangular cross section so as to form a hexagon in the circumferential direction (see FIG. 3).

  A six-pole rotor is formed by inserting six plate-shaped permanent magnets 523 magnetized so that N poles and S poles are alternately arranged inside the permanent magnet insertion hole 522 ( (See FIG. 2).

  For the permanent magnet 523, for example, rare earth mainly containing neodymium, iron, or boron is used.

  Permanent magnet end gaps 524 connected to the permanent magnet insertion holes 522 are formed at both ends of the permanent magnet insertion holes 522.

  In the permanent magnet embedded motor 500, as shown in FIG. 2, a magnetic path r is formed in the outer peripheral core portion of the permanent magnet insertion hole 522, and a reluctance torque is generated by the magnetic path r. Therefore, there is a problem that torque ripple is large and noise increases.

  As one method for solving the problem, as shown in FIGS. 4 to 6, there is known a permanent magnet embedded motor 600 in which a slit is provided in an outer peripheral iron core portion of a permanent magnet insertion hole.

  A permanent magnet embedded motor 600 shown in FIG. 4 includes at least a stator 610 and a rotor 620.

  The stator 610 includes at least a stator core 611 and a winding 614.

  The stator iron core 611 is a thin electromagnetic steel plate (for example, a thickness of about 0.1 to 1.0 mm, a non-oriented electrical steel plate (the crystal axis of each crystal so as not to be biased toward a specific direction of the steel plate and exhibit magnetic properties) The direction is randomly arranged as much as possible))) is punched into a predetermined shape with a mold, and a predetermined number (a plurality) are laminated.

  The stator iron core 611 has a substantially cylindrical cross section as a whole, and includes a ring-shaped core back 615 on the outer peripheral side. Eighteen teeth 612 radially extend from the ring-shaped core back 615 at substantially equal intervals in the circumferential direction. Between two adjacent teeth 612, a slot 613 (18 pieces) in which the winding 614 is accommodated is formed.

  As shown in FIG. 5, the rotor 620 includes at least a rotor core 621 and a permanent magnet 623.

  The rotor core 621 has a substantially circular cross-sectional shape as a whole, a thin electromagnetic steel plate (for example, a thickness of about 0.1 to 1.0 mm, and a non-oriented electrical steel plate (biased in a specific direction of the steel plate). The crystal axis direction of each crystal is arranged as randomly as possible so as not to exhibit magnetic properties))) is punched with a mold into a predetermined shape, and a predetermined number (multiple) is laminated.

  In the rotor core 621, six permanent magnet insertion holes 622 having a rectangular cross section are formed so as to form a hexagon in the circumferential direction (see FIG. 6).

  A six-pole rotor is formed by inserting six plate-shaped permanent magnets 623 magnetized so that N poles and S poles are alternately arranged inside the permanent magnet insertion holes 622 ( (See FIG. 5).

  For the permanent magnet 623, for example, a rare earth mainly composed of neodymium, iron, or boron is used.

  Permanent magnet end gaps 624 connected to the permanent magnet insertion holes 622 are formed at both ends of the permanent magnet insertion holes 622.

  A plurality of slits 625 are formed at predetermined intervals in the circumferential direction in the outer peripheral iron core portion of the permanent magnet insertion hole 622. In the example of FIG. 6, nine slits 625 are formed in one magnetic pole.

  The length of the nine slits 625 in the direction parallel to the magnetic pole center is longest at the slit 625 located at the magnetic pole center, and gradually becomes shorter toward the gap.

  Further, as shown in the enlarged view of FIG. 7, the dimension t in the radial direction of the slit thin portion 626 (which is a thin core portion) between the outer peripheral portion 621a of the rotor core 621 and the slit 625 is 9 of one magnetic pole. It is the same (uniform) in the slits 625.

  FIG. 8 shows the result of comparing the torques of the permanent magnet embedded motor 500 (without the slit 625) and the permanent magnet embedded motor 600 (with the slit 625).

  As shown in FIG. 8, a plurality of slits 625 are formed at predetermined intervals in the circumferential direction in the outer peripheral core portion of the permanent magnet insertion hole 622 of the rotor core 621 (permanent magnet embedded type motor 600). It can be seen that torque ripple (torque pulsation) is smaller than that without 625 (internal permanent magnet motor 500).

  This is due to the reduction in the harmonic component of the induced voltage due to the presence of the slit 625 and the reduction in the cogging torque.

  However, the embedded permanent magnet motor 600 (with slit 625) of FIG. 4 can reduce torque ripple by the slit 625, compared with the embedded permanent magnet motor 500 (without slit 625) of FIG. In order to achieve further noise reduction, further reduction of torque ripple is required.

  In the permanent magnet embedded motor 600 shown in FIG. 4 (with the slit 625), one factor that deteriorates the torque ripple is magnetic saturation of the slit thin portion 626.

  The slit 625 brings the magnetic flux generated from the permanent magnet 623 closer to a sine wave and contributes to the reduction of harmonic components of the induced voltage and the reduction of cogging torque.

  The dimension t in the radial direction of the thin slit portion 626 is set to the minimum dimension that can be processed (generally equivalent to the plate thickness, about 0.1 to 1.0 mm).

  On the other hand, the dimension t in the radial direction of the slit thin portion 626 needs to be a dimension that can withstand centrifugal force.

  Furthermore, there is a restriction from the mold shape, and it is necessary to make it larger than a predetermined dimension.

  However, in order to further limit the magnetic flux (the magnetic flux passing through the magnetic path r in FIG. 2), it is often made as thin and uniform as possible. Also in FIG. 7, the dimension t in the radial direction of the slit thin portion 626 is uniform in each slit thin portion 626.

  However, when the radial dimension t of the slit thin portion 626 is thin and the slit thin portion 626 is uniformly formed, the slit thin portion 626 is magnetically saturated and the magnetic permeability is lowered. As a result, torque ripple deteriorates and noise increases.

  9 to 21 show the first embodiment. FIG. 9 is a cross-sectional view of the permanent magnet embedded motor 100, FIG. 10 is a cross-sectional view of the rotor 120 of FIG. 9, and FIG. FIG. 12 is a partially enlarged view of FIG. 10, FIG. 13 is a partially enlarged view of FIG. 11, FIG. 14 is a partially enlarged view of FIG. 13, and FIG. FIG. 16 is a cross-sectional view of a modified permanent magnet embedded motor 200. FIG. 16 is a diagram showing a torque waveform when the relationship between the torque waveform and the slit thin portion is t1 <t2 <t6 <t3 <t4 <t5. 17 is a cross-sectional view of the rotor 220 of FIG. 16, FIG. 18 is a cross-sectional view of the rotor core 121 of FIG. 17, FIG. 19 is a partially enlarged view of FIG. 17, and FIG. 21 is a partially enlarged view of FIG.

  The configuration of the permanent magnet embedded motor 100 will be described with reference to FIGS. 9 to 14.

  The permanent magnet embedded motor 100 may be simply referred to as an electric motor or a motor.

  A permanent magnet embedded motor 100 shown in FIG. 9 includes at least a stator 110 and a rotor 120.

  The stator 110 includes at least a stator core 111 and a winding 114.

  The stator core 111 is a thin electromagnetic steel plate (for example, a thickness of about 0.1 to 1.0 mm, a non-oriented electrical steel plate (the crystal axis of each crystal so as not to be biased in a specific direction of the steel plate and exhibit magnetic properties). The direction is randomly arranged as much as possible))) is punched into a predetermined shape with a mold, and a predetermined number (a plurality) are laminated.

  The stator core 111 has a substantially cylindrical cross-sectional shape as a whole, and includes a ring-shaped core back 115 on the outer peripheral side. Eighteen teeth 112 extend radially inward from the ring-shaped core back 115 at substantially equal intervals. Between two adjacent teeth 112, a slot 113 (18 pieces) in which the winding 114 is accommodated is formed.

  As shown in FIG. 10, the rotor 120 includes at least a rotor core 121 and a permanent magnet 123.

  The rotor core 121 has a substantially circular cross-sectional shape as a whole, a thin electromagnetic steel plate (for example, a thickness of about 0.1 to 1.0 mm, a non-oriented electrical steel plate (biased in a specific direction of the steel plate). The crystal axis direction of each crystal is arranged as randomly as possible so as not to exhibit magnetic properties))) is punched with a mold into a predetermined shape, and a predetermined number (multiple) is laminated.

  In the rotor core 121, six permanent magnet insertion holes 122 having a rectangular cross section are formed so as to form a hexagon in the circumferential direction (see FIG. 11).

  A six-pole rotor is formed by inserting six flat-plate-shaped permanent magnets 123 magnetized so that N poles and S poles are alternately arranged inside the permanent magnet insertion hole 122.

  For the permanent magnet 123, for example, rare earth mainly containing neodymium, iron, or boron is used.

  Permanent magnet end gaps 124 connected to the permanent magnet insertion holes 122 are formed at both ends of the permanent magnet insertion holes 122.

  A plurality of slits 125 a to 125 e extend in parallel to the magnetic pole center and are formed at predetermined intervals in the circumferential direction in the outer peripheral core portion of the permanent magnet insertion hole 122. In the example of FIG. 11, nine slits 125a to 125e are formed in one magnetic pole.

  As shown in FIGS. 12 and 13, the nine slits 125a to 125e of one magnetic pole are arranged symmetrically with respect to the magnetic pole center.

  A slit 125a is disposed at the center of the magnetic pole. A slit 125b, a slit 125c, a slit 125d, and a slit 125e are sequentially arranged on both sides of the slit 125a.

  The thin core portion between the outer peripheral portion 121a of the rotor core 1 and the slit 125a, slit 125b, slit 125c, slit 125d, and slit 125e is divided into a slit thin portion 126a, a slit thin portion 126b, a slit thin portion 126c, and a slit, respectively. The thin portion 126d and the slit thin portion 126e are used.

  The thin core portion between the outer peripheral portion 121a of the rotor core 1 and the permanent magnet end gap 124 is referred to as a permanent magnet end thin portion 124a.

And as shown in FIG. 14, the dimension (diameter direction) of each thin iron core part is defined as shown below.
t1 = dimension of permanent magnet end thin portion 124a t2 = dimension of slit thin portion 126e t3 = dimension of slit thin portion 126d t4 = dimension of slit thin portion 126c t5 = dimension of slit thin portion 126b t6 = dimension of slit thin portion 126a Size

  First, the relationship between t1, t2, t3, t4, t5, and t6 shown in FIG. 14 is set to t1 <t2, t3, t4, t5, and t6, whereby the induced voltage is improved and the torque ripple is reduced. explain.

  As already described (FIG. 7), by forming the thin slit portion thinly and uniformly, the thin slit portion is magnetically saturated and the magnetic permeability is lowered. Then, the torque ripple deteriorates and the noise increases. Therefore, the torque ripple can be reduced by increasing the thickness of the thin slit portion and reducing the influence of magnetic saturation of the thin slit portion. However, if the permanent magnet end thin portion 124a is increased, the leakage of magnetic flux increases, and the induced voltage decreases.

  Therefore, by setting t1 <t2, t3, t4, t5, t6, the influence of magnetic saturation of the slit thin portions 126a to 126e can be reduced without increasing the leakage magnetic flux from the permanent magnet end thin portion 124a. Torque ripple can be reduced.

  Here, t1 is preferably as thin as possible, but is set to the minimum dimension (generally equivalent to the plate thickness, about 0.1 to 1.0 mm) that can be processed (pressing of the magnetic steel sheet). This is because it is necessary to make t1 greater than a predetermined dimension (plate thickness of the electromagnetic steel sheet) mainly due to the restriction of the die for press working of the electromagnetic steel sheet.

  Further, by setting t1 <t2 <t3, t4, t5, and t6, it is possible to suppress an increase in torque ripple due to thin magnetic saturation while further improving the induced voltage.

  The effect of setting t1 <t2 <t3, t4, t5, and t6 will be described below.

  The slit thin portion 126e (dimension t2) of the slit 125e closest to the pole prevents leakage of magnetic flux (leakage of magnetic flux of the permanent magnet 123 between the poles), similarly to the permanent magnet end thin portion 124a (dimension t1). There is also an effect. By making the slit thin portion 126e (dimension t2) of the slit 125e thin, it is possible to improve the induced voltage.

  However, since the permanent magnet end thin portion 124a (dimension t1) is close to the interpolar portion, the magnetic flux density is low, and it is difficult to be affected by an increase in torque ripple due to the effect of magnetic saturation. Causes torque ripple to increase due to magnetic saturation.

  Therefore, the thin slit portion 126e (dimension t2) is thinned to such a dimension that does not cause magnetic saturation.

  Therefore, the relationship is t1 <t2 <t3, t4, t5, t6. By satisfying this relationship, it is possible to obtain the effects of improving the induced voltage and reducing torque ripple.

  In addition, torque ripple can be reduced by setting t1 <t2 <t6 <t3, t4, and t5. The effects of setting t1 <t2 <t6 <t3, t4, and t5 will be described below.

  Since the magnetic flux is received from the stator when the motor rotates, the magnetic flux distribution of the rotor becomes asymmetric due to the influence of the armature reaction. Since the slit thin portion 126a (dimension t6) closest to the magnetic pole center exists at the magnetic pole center, it has a characteristic of maintaining the symmetry of the magnetic pole of the rotor. Therefore, if t6 is excessively increased, torque ripple increases due to the influence of the armature reaction.

  Therefore, by setting t1 <t2 <t6 <t3, t4, and t5, it is possible to suppress the magnetic saturation of the slit thin portions 126a to 126e while suppressing the influence of the armature reaction, thereby reducing the torque ripple. .

  Furthermore, torque ripple can be reduced by setting t1 <t2 <t6 <t3 <t4 <t5. The effect of setting t1 <t2 <t6 <t3 <t4 <t5 will be described below.

  If t3, t4, and t5 are too thin, torque ripple increases due to the effect of magnetic saturation. Therefore, it is preferable to increase the size. However, the closer to the magnetic pole center, the higher the magnetic flux density, so the slit near the magnetic pole center is susceptible to magnetic saturation. Therefore, it is necessary to enlarge the dimension of the slit thin part in the radial direction closer to the magnetic pole center.

  Further, as already described, the slit thin portion 126a (dimension t6) closest to the magnetic pole center reduces the influence of the armature reaction, so that if t6 is excessively increased, the torque ripple increases.

  Therefore, by satisfying the relationship of t1 <t2 <t6 <t3 <t4 <t5, the induced voltage is improved, the influence of the armature reaction is suppressed, and the torque ripple can be reduced.

  FIG. 15 shows a torque waveform in which the dimension of the slit thin portion is uniform and a torque waveform when the relationship between the slit thin portion is t1 <t2 <t6 <t3 <t4 <t5.

  From FIG. 15, it can be seen that the torque ripple can be suppressed by setting the relationship of t1 <t2 <t6 <t3 <t4 <t5. It can be said that the relation of t1 <t2 <t6 <t3 <t4 <t5 is effective in reducing noise.

  The configuration of a modified permanent magnet embedded motor 200 will be described with reference to FIGS.

  In the modified permanent magnet embedded motor 200, when there is no permanent magnet in the permanent magnet insertion hole on the extension line of the rotor slit (parallel to the magnetic pole center), the slit and the permanent magnet insertion hole are connected. (The reference numerals are omitted here).

  The permanent magnet embedded motor 200 may be simply referred to as an electric motor or a motor.

  The embedded permanent magnet motor 200 shown in FIG. 16 includes at least a stator 210 and a rotor 220.

  The stator 210 includes at least a stator core 211 and a winding 214.

  The stator core 211 is a thin electromagnetic steel plate (for example, a thickness of about 0.1 to 1.0 mm and a non-oriented electrical steel plate (the crystal axis of each crystal so as not to be biased in a specific direction of the steel plate and exhibit magnetic properties). The direction is randomly arranged as much as possible))) is punched into a predetermined shape with a mold, and a predetermined number (a plurality) are laminated.

  The stator core 211 is substantially cylindrical in overall cross-sectional shape, and includes a ring-shaped core back 215 on the outer peripheral side. Eighteen teeth 212 extend radially inward from the ring-shaped core back 215 at substantially equal intervals in the circumferential direction. Between two adjacent teeth 212, a slot 213 (18 pieces) in which the winding 214 is accommodated is formed.

  As shown in FIG. 17, the rotor 220 includes at least a rotor core 221 and a permanent magnet 223.

  The rotor core 221 has a substantially circular cross-sectional shape as a whole, a thin electromagnetic steel plate (for example, a thickness of about 0.1 to 1.0 mm, and a non-oriented electrical steel plate (biased in a specific direction of the steel plate). The crystal axis direction of each crystal is arranged as randomly as possible so as not to exhibit magnetic properties))) is punched with a mold into a predetermined shape, and a predetermined number (multiple) is laminated.

  The rotor core 221 is formed with six permanent magnet insertion holes 222 having a rectangular cross section so as to form a hexagon in the circumferential direction (see FIG. 18).

  A six-pole rotor is formed by inserting six flat plate-shaped permanent magnets 223 magnetized so that N poles and S poles are alternately arranged inside the permanent magnet insertion hole 222.

  For the permanent magnet 223, for example, a rare earth mainly containing neodymium, iron, or boron is used.

  Permanent magnet end gaps 224 connected to the permanent magnet insertion holes 222 are formed at both ends of the permanent magnet insertion holes 222.

  A plurality of slits 225 a to 225 e extend in parallel to the magnetic pole center and are formed at predetermined intervals in the circumferential direction in the outer peripheral iron core portion of the permanent magnet insertion hole 222. In the example of FIG. 18, nine slits 225a to 225e are formed in one magnetic pole.

  As shown in FIGS. 19 and 20, the nine slits 225a to 225e of one magnetic pole are arranged symmetrically with respect to the magnetic pole center.

  A slit 225a is disposed at the magnetic pole center. On both sides of the slit 225a, a slit 225b, a slit 225c, a slit 225d, and a slit 225e are sequentially arranged.

  The slit 225e is connected to the permanent magnet insertion hole 222. And the permanent magnet 223 does not exist in the part connected with the slit 225e of the permanent magnet insertion hole 222.

  When the slits 225a to 225d where the permanent magnet 223 exists on the extension line (parallel to the center of the magnetic pole) are connected to the permanent magnet insertion hole 222, the permanent magnet 223 contacts the gap (slits 225a to 225d). Therefore, the permeance is reduced, and the demagnetization resistance and the magnetic flux are reduced.

  However, the slit 225e in which the permanent magnet 223 does not exist in the permanent magnet insertion hole 222 on the extension line (parallel to the magnetic pole center) does not change the permeance of the permanent magnet 223 even when connected to the permanent magnet insertion hole 222. It does not affect the characteristics of H.223.

  Furthermore, since the molds of the permanent magnet insertion hole 222 and the slit 225e can be integrated by connecting the slit 225e and the permanent magnet insertion hole 222, the mold becomes smaller and the cost of the mold is suppressed. Can do.

  The thin core portion between the outer peripheral portion 221a of the rotor core 221 and the slit 225a, slit 225b, slit 225c, slit 225d, and slit 225e is divided into a slit thin portion 226a, a slit thin portion 226b, a slit thin portion 226c, and a slit, respectively. The thin portion 226d and the slit thin portion 226e are used.

  The thin core portion between the outer peripheral portion 221a of the rotor core 221 and the permanent magnet end gap 224 is referred to as a permanent magnet end thin portion 224a.

And as shown in FIG. 21, the dimension of each thin iron core part is defined as shown below.
t1 = dimension of the permanent magnet end thin portion 224a t2 = dimension of the slit thin portion 226e t3 = dimension of the slit thin portion 226d t4 = dimension of the slit thin portion 226c t5 = dimension of the slit thin portion 226b t6 = dimension of the slit thin portion 226a Size

  First, the relationship between t1, t2, t3, t4, t5, and t6 shown in FIG. 21 is set to t1 <t2, t3, t4, t5, and t6, whereby the induced voltage is improved and the torque ripple is reduced. explain.

  As already described (FIG. 7), by forming the thin slit portion thinly and uniformly, the thin slit portion is magnetically saturated and the magnetic permeability is lowered. Then, the torque ripple deteriorates and the noise increases. Therefore, the torque ripple can be reduced by increasing the thickness of the thin slit portion and reducing the influence of magnetic saturation of the thin slit portion. However, if the permanent magnet end portion thin portion 224a is increased, magnetic flux leakage increases and the induced voltage decreases.

  Therefore, by setting t1 <t2, t3, t4, t5, and t6, the leakage magnetic flux from the permanent magnet end thin part 224a is not increased, and the influence of magnetic saturation of the slit thin parts 226a to 226e is reduced. Torque ripple can be reduced.

  Here, t1 is preferably as thin as possible, but is set to the minimum dimension (generally equivalent to the plate thickness, about 0.1 to 1.0 mm) that can be processed (pressing of the magnetic steel sheet). This is because it is necessary to make t1 greater than a predetermined dimension (plate thickness of the electromagnetic steel sheet) mainly due to the restriction of the die for press working of the electromagnetic steel sheet.

  Further, by setting t1 <t2 <t3, t4, t5, and t6, it is possible to suppress an increase in torque ripple due to thin magnetic saturation while further improving the induced voltage.

  The effect of setting t1 <t2 <t3, t4, t5, and t6 will be described below.

  The slit thin portion 226e (dimension t2) of the slit 225e closest to the pole prevents leakage of magnetic flux (magnetic flux leakage of the permanent magnet 223 between the poles) in the same manner as the permanent magnet end thin portion 224a (dimension t1). There is also an effect. By reducing the thin slit portion 226e (dimension t2) of the slit 225e, the induction voltage can be improved.

  However, since the permanent magnet end thin portion 224a (dimension t1) is close to the inter-pole portion, the magnetic flux density is low, and it is difficult to be affected by an increase in torque ripple due to the effect of magnetic saturation, but the slit thin portion 226e (dimension t2). Causes torque ripple to increase due to magnetic saturation.

  Therefore, the slit thin part 226e (dimension t2) is thinned to such a dimension that does not cause magnetic saturation.

  Therefore, the relationship is t1 <t2 <t3, t4, t5, t6. By satisfying this relationship, it is possible to obtain the effects of improving the induced voltage and reducing torque ripple.

  In addition, torque ripple can be reduced by setting t1 <t2 <t6 <t3, t4, and t5. The effects of setting t1 <t2 <t6 <t3, t4, and t5 will be described below.

  Since the magnetic flux is received from the stator when the motor rotates, the magnetic flux distribution of the rotor becomes asymmetric due to the influence of the armature reaction. Since the thin slit portion 226a (dimension t6) closest to the magnetic pole center exists at the magnetic pole center, it has a characteristic of maintaining the symmetry of the magnetic pole of the rotor. Therefore, if t6 is excessively increased, torque ripple increases due to the influence of the armature reaction.

  Therefore, by setting t1 <t2 <t6 <t3, t4, and t5, it is possible to suppress the magnetic saturation of the slit thin portions 226a to 226e while suppressing the influence of the armature reaction, thereby reducing the torque ripple. .

  Furthermore, torque ripple can be reduced by setting t1 <t2 <t6 <t3 <t4 <t5. The effect of setting t1 <t2 <t6 <t3 <t4 <t5 will be described below.

  If t3, t4, and t5 are too thin, torque ripple increases due to the effect of magnetic saturation. Therefore, it is preferable to increase the size. However, the closer to the magnetic pole center, the higher the magnetic flux density, so the slit near the magnetic pole center is susceptible to magnetic saturation. Therefore, it is necessary to enlarge the dimension of the slit thin part in the radial direction closer to the magnetic pole center.

  Further, as already described, the slit thin portion 226a (dimension t6) closest to the magnetic pole center reduces the influence of the armature reaction, so that if t6 is excessively increased, the torque ripple increases.

  Therefore, by satisfying the relationship of t1 <t2 <t6 <t3 <t4 <t5, the induced voltage is improved, the influence of the armature reaction is suppressed, and the torque ripple can be reduced.

  In the modified permanent magnet embedded motor 200, the mold of the permanent magnet insertion hole 222 and the slit 225e can be integrated by connecting the slit 225e and the permanent magnet insertion hole 222. It becomes small and can suppress the cost of a metal mold | die.

  Further, the dimension of each thin slit portion is t1 <t2, t3, t4, t5, t6, or t1 <t2, t3, t4, t5, t6, or t1 <t2 <t3, t4, t5, t6, or t1. The relationship of <t2 <t6 <t3, t4, t5, or t1 <t2 <t6 <t3 <t4 <t5 improves the induced voltage while suppressing the cost of the mold and suppresses the influence of the armature reaction. Torque ripple can be reduced.

  In the present embodiment, it has been shown that by increasing the dimension of the thin slit portion, the magnetic saturation of the thin slit portion can be relaxed, which is effective in reducing torque ripple.

  As the dimension of the thin slit portion is increased, the characteristics approximate to those of the general permanent magnet embedded motor 500 (no slit) shown in FIG.

  That is, even if the slit thin portion is made too large, there is a possibility that the torque ripple is deteriorated.

  Therefore, the dimension of the slit thin part is made smaller than six times the dimension t1 of the permanent magnet end thin part 124a, 224a between the permanent magnet end part gaps 124, 224 and the rotor outer peripheral parts 121a, 221a. As a result, the magnetic saturation of the slit thin portion is relaxed, and torque ripple can be further reduced.

This can be expressed as an expression:
6 × t1> t2, t3, t4, t5, t6
It becomes.

Furthermore, the size of the slit in the radial direction is important for the effect of the slit. As shown in FIGS. 17 and 21, the radial dimension of the slit is
L2 = diameter dimension of slit 125e and slit 225e L3 = diameter dimension of slit 125d and slit 225d L4 = diameter dimension of slit 125c and slit 225c L5 = diameter dimension of slit 125b and slit 225b L6 = It is set as the dimension of the radial direction of the slit 125a and the slit 225a.

  By making the dimension of each slit thin part smaller than the dimension in the radial direction of each slit, the effect of the slit can be achieved, and the effect of the slit can also be exhibited while relaxing the magnetic saturation of the slit thin part. Torque ripple can be reduced.

That is,
t2 <L2
t3 <L3
t4 <L4
t5 <L5
t6 <L6
It is.

  Further, as an effect of the present embodiment, it is possible to reduce the harmonic component of the induced voltage by suppressing the influence of the magnetic saturation of the thin slit portion, and the high-efficiency rotor with reduced harmonic iron loss. Can be configured.

  In addition, since the torque ripple is reduced, a low-vibration rotor can be formed, so that a long-life rotor can be obtained.

  The slit is preferably substantially perpendicular to the permanent magnet. If the slit is not perpendicular to the permanent magnet (the slit is not parallel), the dimension between the slits becomes gradually narrower and the magnetic flux density increases, resulting in magnetic saturation and a reduction in induced voltage. End up.

  If the slit is perpendicular to the permanent magnet, the magnetic flux density in the portion between the slits is constant, so magnetic saturation does not occur and there is no reduction in efficiency due to magnetic saturation. Is obtained.

  The rotor described above is a rotor having 6 poles. However, by applying the present embodiment to a rotor other than 6 poles, the induced voltage is improved and the influence of the armature reaction is exerted. The torque ripple can be reduced, and a highly efficient and low noise rotor can be configured.

  Further, although the number of slits is 9 per magnetic pole, there is no restriction on the number of slits. The effect of this embodiment can be achieved regardless of the number of slits.

  When the number of slits is an even number, there are two slits closest to the magnetic pole center. In this case, since two slits are the slits closest to the magnetic pole center, there are two slit thin portions at the magnetic pole center. It becomes a target.

  Further, although the stators 110 and 210 of the present embodiment have a configuration of 18 slots and 6 poles distributed winding, because of the effect of reducing torque ripple by the rotor, the number of slots, winding method (concentrated winding, distributed winding) The effect can be obtained regardless of the number of poles.

  In addition, when a sintered rare earth magnet is used as a permanent magnet, the sintered rare earth magnet has a high magnetic force, so that the magnetic flux density of the rotor is higher than when other magnets are used, and the influence of the slit is increased.

  For this reason, the use of a sintered rare earth magnet for the rotor can provide more effects.

  Further, by mounting the permanent magnet embedded motors 100 and 200 of the present embodiment on a compressor such as a refrigeration cycle apparatus or a blower such as an air conditioner, a highly efficient, low-cost, long-life compressor, A blower is obtained.

  100 permanent magnet embedded motor, 110 stator, 111 stator core, 112 teeth, 113 slots, 114 windings, 115 core back, 120 rotor, 121 rotor core, 121a outer periphery, 122 permanent magnet insertion hole, 123 permanent magnet, 124 permanent magnet end gap, 124a permanent magnet end thin portion, 125a slit, 125b slit, 125c slit, 125d slit, 125e slit, 126a slit thin portion, 126b slit thin portion, 126c slit thin portion, 126d Slit thin part, 126e Slit thin part, 200 Permanent magnet embedded motor, 210 Stator, 211 Stator core, 212 teeth, 213 slots, 214 windings, 215 core back, 220 rotor, 221 rotor core 221a outer periphery, 222 permanent magnet insertion hole, 223 permanent magnet, 224 permanent magnet end gap, 224a permanent magnet end thin part, 225a slit, 225b slit, 225c slit, 225d slit, 225e slit, 226a slit thin part, 226b Slit thin section, 226c Slit thin section, 226d Slit thin section, 226e Slit thin section, 500 Permanent magnet embedded motor, 510 Stator, 511 Stator iron core, 512 teeth, 513 slots, 514 winding, 515 core back, 520 Rotor, 521 Rotor core, 522 Permanent magnet insertion hole, 523 Permanent magnet, 524 Permanent magnet end gap, 600 Permanent magnet embedded motor, 610 Stator, 611 Stator core, 612 teeth, 613 slots 614 winding, 615 core back, 620 rotor, 621 rotor core, 622 permanent magnet insertion hole, 623 permanent magnet, 624 a permanent magnet end gap, 625 slit, 626 slit the thin portion.

Claims (9)

A rotor core formed by laminating a predetermined number of electromagnetic steel sheets punched into a predetermined shape;
A plurality of permanent magnet insertion holes formed along the outer periphery of the rotor core;
Permanent magnet end gaps provided at both ends of the permanent magnet insertion hole;
A permanent magnet inserted into the permanent magnet insertion hole;
A plurality of slits formed in the iron core outside the permanent magnet insertion hole;
The radial dimension of the slit thin portion between each of the plurality of slits and the outer periphery of the rotor core is the same as the thickness of the permanent magnet end thin portion between the permanent magnet end gap and the outer periphery of the rotor core. A rotor of an embedded permanent magnet motor, wherein the rotor is larger than the radial dimension of the motor.   The radial dimension of the slit thin part of the plurality of slits gradually increases from the gap toward the magnetic pole center, and the radial dimension of the slit thin part of the slit closest to the magnetic pole center is: The rotor of a permanent magnet embedded motor according to claim 1, wherein the size is smaller than the dimension in the radial direction of the thin slit portion of the other slit.   3. The rotor of a permanent magnet embedded motor according to claim 1, wherein the slit in which the permanent magnet does not exist on an extension line parallel to the magnetic pole center is connected to the permanent magnet insertion hole. .   The rotor of a permanent magnet embedded motor according to any one of claims 1 to 3, wherein the plurality of slits are arranged substantially perpendicular to the permanent magnet insertion hole.   The radial dimension of the slit thin portion between each of the plurality of slits and the outer periphery of the rotor core is the same as the thickness of the permanent magnet end thin portion between the permanent magnet end gap and the outer periphery of the rotor core. The rotor of an embedded permanent magnet motor according to any one of claims 1 to 4, wherein the rotor is smaller than six times the radial dimension.   The radial dimension of the slit thin part between each of the plurality of slits and the outer periphery of the rotor core is smaller than the radial dimension of each of the plurality of slits. A rotor of a permanent magnet embedded motor according to any one of claims 1 to 5.   The rotor of a permanent magnet embedded motor according to claim 1, wherein a rare earth magnet is used as the permanent magnet.   A blower comprising the rotor of a permanent magnet embedded motor according to any one of claims 1 to 7.   A compressor comprising the rotor of the permanent magnet embedded motor according to any one of claims 1 to 7.

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