JP2011097754A - Permanent magnet embedded motor and blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet embedded motor of high efficiency, low cost, and high-speed rotation which assures a strength against a centrifugal force at high speed rotation and can be controlled by a position sensorless 120° electrification method, along with a blower using the same. <P>SOLUTION: In the permanent magnet embedded motor 100, a rotor 90 includes a rotor core 4 in which a plurality of thin electromagnetic steel plates are laminated, a plurality of magnet insert holes 5 each of which is provided along the outer peripheral edge of the rotator core 4 and has an arc-like non-magnetic material 9 with both ends in circumferential direction being bent inward wherein the entire almost U-shaped, a plurality of permanent magnets 6 embedded in the magnet insert holes 5, and a slit 7 which is provided at part of the rotor core 4 arranged on the outer peripheral side of the permanent magnets 6, comprising an air layer. The non-magnetic material 9 is arranged further inside the outer peripheral side surface of the permanent magnet 6 to extend toward the inside diameter side beyond the inner peripheral side surface of the permanent magnet 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a permanent magnet embedded type electric motor that is mainly used for a blower or the like and performs high-speed rotation. The present invention also relates to a blower equipped with the permanent magnet embedded motor.

  In the permanent magnet embedded type electric motor, a design method for narrowing the magnetic path of the outer peripheral portion between the magnetic poles of the rotor has been conventionally used in order to reduce the leakage magnetic flux between the magnetic poles. At this time, in an electric motor that rotates at high speed, mechanical strength due to centrifugal force becomes a problem.

  Conventionally, the permanent magnet reluctance type rotating electrical machine can be easily inserted into the permanent magnet during assembly, and the mechanization of the manufacturing can be facilitated. Even when the adhesive for fixing the permanent magnet is deteriorated, In order to eliminate the possibility of breakage of the rotor and to achieve high output, high efficiency, high speed, and high reliability, a permanent magnet positioning projection is provided in the permanent magnet embedding hole so that the permanent magnet is supported. did. In addition, by optimizing the shape of the thin part in the rotor core, a permanent magnet reluctance type rotating electrical machine that reduces the leakage of magnetic flux generated from the permanent magnet and ensures the strength of the thin part where stress is concentrated has been proposed. (For example, refer to Patent Document 1).

  Further, in order to ensure both the mechanical strength of the rotor (rotor) and the suppression of leakage magnetic flux, the rotor has a plurality of magnetic poles, and a yoke in which a slot is formed at a position corresponding to each magnetic pole, The yoke has a bridge at both ends of the slot, and the thickness of the bridge decreases continuously or stepwise from the rotation center side of the rotor toward the outer periphery. A motor (electric motor) is proposed (see, for example, Patent Document 2).

JP 2001-339919 A JP-A-9-224338

  However, the permanent magnet type reluctance type rotating electrical machine disclosed in Patent Document 1 has a large stress concentration in the thin portion between the air hole on the outer periphery of the permanent magnet and the outer periphery of the rotor core during high speed rotation. Therefore, there is a problem that the magnetic flux leakage between the poles increases and the characteristics of the rotating electrical machine deteriorate.

  In addition, in the motor of Patent Document 2, sufficient mechanical strength may not be obtained at a high speed rotation in which the rotation speed of the rotor exceeds 10,000 rpm per minute (number of rotations / minute).

  The present invention has been made to solve the above-described problems, and ensures high strength against centrifugal force during high-speed rotation, and can be controlled by a position sensorless 120-degree energization method, with high efficiency, low cost, and high-speed rotation. Provided are a permanent magnet embedded type electric motor capable of achieving the above and a blower using the permanent magnet embedded type electric motor.

In the embedded permanent magnet electric motor according to the present invention, the rotor is disposed inside the stator with the stator core wound with a gap, and the position sensorless 120 does not detect the rotational position of the rotor with the position sensor. In the permanent magnet embedded type motor controlled by the power supply method,
The rotor is
A rotor core constructed by laminating a plurality of thin electromagnetic steel sheets;
A plurality of magnet insertion holes provided along the outer peripheral edge of the rotor core, and having an arcuate non-magnetic body part that is substantially U-shaped as a whole and whose circumferential ends are bent inward;
A plurality of permanent magnets embedded in the magnet insertion hole;
Provided in a part of the rotor core disposed on the outer peripheral side of the permanent magnet, and comprising a slit made of a nonmagnetic layer,
The non-magnetic part is configured to be arranged on the inner side of the outer peripheral surface of the permanent magnet, and is formed to extend to the inner diameter side of the inner peripheral surface of the permanent magnet.

  The embedded permanent magnet electric motor according to the present invention has a configuration in which the magnet insertion hole has a substantially U-shape as a whole and has an arc-shaped non-magnetic body portion whose inner ends are bent inward, and the outer periphery of the permanent magnet By arranging a slit made of a non-magnetic layer on the side, it is possible to relieve stress against centrifugal force during high-speed rotation and to realize high-speed operation with a position sensorless 120-degree energization method.

FIG. 3 shows the first embodiment and is a cross-sectional view of the permanent magnet embedded motor 100. FIG. The elements on larger scale of FIG. FIG. 5 shows the first embodiment, and is a cross-sectional view of a stator 80. FIG. 3 shows the first embodiment and is a plan view of the stator core 1. The elements on larger scale of FIG. FIG. 5 shows the first embodiment, and is a cross-sectional view of a rotor 90. FIG. 5 shows the first embodiment and is a plan view of the rotor core 4. FIG. 5 shows the first embodiment, and is an enlarged view of the vicinity of the interpolar portion of the rotor core 4. The elements on larger scale of FIG. FIG. 5 shows the first embodiment, and is a cross-sectional view of a permanent magnet embedded electric motor 200 of a first modification. FIG. 5 shows the first embodiment, and is a cross-sectional view of a rotor 190 of a first modification. FIG. 5 shows the first embodiment, and is a plan view of a rotor core 104 of a first modification. The elements on larger scale of FIG. FIG. 5 shows the first embodiment, and is an enlarged view of the vicinity of the interpolar part of the rotor core 104. FIG. FIG. 5 shows the first embodiment, and is a cross-sectional view of a permanent magnet embedded type electric motor 300 according to a second modification. The elements on larger scale of FIG. FIG. 5 shows the first embodiment and is a cross-sectional view of a rotor 290 of a second modification. FIG. 5 shows the first embodiment and is a plan view of a rotor core 204 of a second modification. FIG. 5 shows the first embodiment, and is an enlarged view of the vicinity of the interpolar portion of the rotor core 204. FIG. FIG. 5 shows the first embodiment, and is a transverse cross-sectional view of a permanent magnet embedded electric motor 400 according to Modification 3. FIG. 5 shows the first embodiment and is a cross-sectional view of a rotor 390 of a third modification. FIG. 5 shows the first embodiment and is a plan view of a rotor core 304 of a third modification. FIG. 5 shows the first embodiment, and is an enlarged view of the vicinity of the slit 307 of the rotor core 304. The enlarged view of FIG. FIG. 5 shows the first embodiment and is an enlarged view of a slit 307; FIG. 5 shows the first embodiment, and is an enlarged view of the vicinity of the interpolar portion of the rotor core 304. It is a figure shown for a comparison, and is an enlarged view of the vicinity of the interpolar part of the rotor core 404 in which the radius of the fourth arc portion 454 is increased.

Embodiment 1 FIG.
1 to 26 show the first embodiment. FIG. 1 is a cross-sectional view of a permanent magnet embedded motor 100, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 4 is a plan view of the stator core 1, FIG. 5 is a partially enlarged view of FIG. 4, FIG. 6 is a cross-sectional view of the rotor 90, FIG. 7 is a plan view of the rotor core 4, and FIG. 9 is an enlarged view of the vicinity of the inter-electrode portion, FIG. 9 is a partially enlarged view of FIG. 6, FIG. 10 is a cross-sectional view of the permanent magnet embedded electric motor 200 of Modification 1, and FIG. FIG. 12 is a plan view of the rotor core 104 of the first modification, FIG. 13 is a partially enlarged view of FIG. 12, FIG. 14 is an enlarged view of the vicinity of the interpole portion of the rotor core 104, and FIG. FIG. 16 is a partially enlarged view of FIG. 15, FIG. 17 is a cross-sectional view of a rotor 290 of a second modification, and FIG. 18 is a second modification. 19 is a plan view of the rotor core 204, FIG. 19 is an enlarged view of the vicinity of the inter-pole portion of the rotor core 204, FIG. 20 is a transverse cross-sectional view of the permanent magnet embedded type electric motor 400 of Modification 3, and FIG. 22 is a cross-sectional view of the rotor 390, FIG. 22 is a plan view of the rotor core 304 of Modification 3, FIG. 23 is an enlarged view of the vicinity of the slit 307 of the rotor core 304, FIG. 24 is an enlarged view of FIG. 26 is an enlarged view of the slit 307, and FIG.

  FIG. 27 is a view for comparison, and is an enlarged view of the vicinity of the inter-pole portion of the rotor core 404 in which the radius of the fourth arc portion 454 is increased.

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

  As shown in FIG. 1, the embedded permanent magnet electric motor 100 includes at least a stator 80 and a rotor 90.

  Hereinafter, the permanent magnet embedded type electric motor 100 may be simply referred to as a motor or an electric motor.

  As shown in FIG. 3, the stator 80 includes at least the stator core 1, the winding 3, and an insulating material (slot cell or the like) (not shown).

  The stator core 1 has a donut-like overall cross-sectional shape, and a core back 23 having a ring-like cross-sectional shape is formed on the outer peripheral side. From the core back 23, twelve tooth portions 21 are radially provided on the inner side at substantially equal intervals in the circumferential direction (see FIG. 4).

  The circumferential width of the tooth portion 21 is substantially uniform in the radial direction. That is, the tooth portion 21 has a substantially parallel shape toward the inner peripheral side of the stator core 1. The tip portion 21a on the inner diameter side of the tooth portion 21 has an arc shape in which both sides spread in the circumferential direction (see FIGS. 4 and 5). However, it does not have to be arcuate, and may be linear, for example.

  A space surrounded by two adjacent tooth portions 21 and a part of the core back 23 is referred to as a slot 22. Since the number of the tooth portions 21 is twelve, the number of the slots 22 is twelve.

  Since the circumferential width of the tooth portion 21 is substantially uniform in the radial direction, the circumferential width of the slot 22 gradually increases from the inside toward the outside (see FIGS. 4 and 5).

  The inner peripheral side (rotor 90 side) of the slot 22 is open. The open portion of the slot 22 on the inner peripheral side (rotor 90 side) is referred to as a slot opening 22a (see FIG. 5).

  The winding 3 is inserted into the slot 22 through the slot opening 22a.

  Each slot 22 is provided with a winding 3 wound in a three-phase four-pole distributed winding method via an insulating material (not shown) such as a slot cell. For the winding 3, a magnet wire or the like in which an insulating film is applied to the outside of the copper wire is used.

  The stator core 1 is a thin electromagnetic steel sheet (for example, a non-oriented electrical steel sheet having a thickness of about 0.1 to 1.0 mm (the crystal axis direction of each crystal so as not to be biased toward a specific direction of the steel sheet and exhibit magnetic properties). Are randomly arranged as much as possible))) in a predetermined shape with a mold, and a predetermined number (multiple) is laminated.

  The rotor 90 disposed on the inner diameter side of the stator 80 via the gap 25 (see FIG. 2) includes at least the rotor core 4, the permanent magnet 6, and the output shaft 60. The four permanent magnets 6 are arranged so that the polarities in the circumferential direction are alternately different to constitute a four-pole rotor 90 (see FIG. 6).

  Similarly to the stator core 1, the rotor core 4 is also formed by punching a thin electromagnetic steel sheet (for example, a non-oriented electrical steel sheet having a thickness of about 0.1 to 1.0 mm) into a predetermined shape with a die, and a predetermined number of sheets. (Multiple sheets) are configured by stacking.

  For the rotor core 4, an electromagnetic steel plate made of the same material as the stator core 1 may be used, or an electromagnetic steel plate made of another material may be used. For example, the thickness of the electromagnetic steel plate of the stator core 1 may be set to a material thinner than the thickness of the electromagnetic steel plate of the rotor core 4. Thereby, the iron loss of the stator core 1 can be reduced, and the highly efficient embedded permanent magnet electric motor 100 can be obtained.

  The rotor core 4 is provided with four magnet insertion holes 5 at substantially equal intervals in the circumferential direction along the outer peripheral edge (see FIG. 7). Four permanent magnets 6 in the form of flat plates are inserted into the four magnet insertion holes 5 so that the polarities are alternately reversed to constitute a four-pole rotor 90 (see FIG. 6).

  The gap 25 between the stator 80 and the rotor 90 has, for example, a radial dimension of about 0.2 to 2.0 mm (see FIG. 2).

  6 to 8, the rotor 90 and the rotor core 4 of the embedded permanent magnet electric motor 100 will be described in more detail.

  The rotor core 4 is provided with magnet insertion holes 5 for embedding the plate-like permanent magnets 6 at substantially equal intervals in the circumferential direction along the outer peripheral edge (see FIG. 7).

  Further, a shaft hole 10 into which the output shaft 60 is fitted is formed in a substantially central portion of the rotor core 4 (see FIG. 7).

  In this embodiment, four flat permanent magnets 6 are inserted into four magnet insertion holes 5 (see FIG. 6). The permanent magnet 6 is preferably a neodymium rare earth permanent magnet, but may be a permanent magnet 6 made of another material (for example, ferrite).

  The position of the permanent magnet 6 in the circumferential direction is determined by a permanent magnet stopper 51 formed near both ends of the magnet insertion hole 5 (see FIG. 8).

  About the lamination | stacking method of the thin electromagnetic steel plate which comprises the rotor core 4, you may fix with a crimping | crimping or a rivet, and you may fix using an adhesive agent.

  The entire magnet insertion hole 5 is substantially U-shaped, and both ends of the magnet insertion hole 5 are bent toward the output shaft 60 side. The permanent magnet 6 does not exist in the bent portions at both ends, and constitutes a nonmagnetic body portion 9 such as an air layer (see FIG. 6).

  The non-magnetic body portion 9 formed adjacent to the circumferential end portion of the permanent magnet 6 has a lower magnetic permeability than the electromagnetic steel plate constituting the rotor core 4, so that it is difficult for the magnetic flux to pass therethrough and the magnetic path through which the magnetic flux passes. It has a role of controlling (leakage magnetic flux).

  When the leakage magnetic flux between the adjacent permanent magnets 6 increases, the magnetic flux of the rotor 90 becomes difficult to flow to the stator 80, and the characteristics of the permanent magnet embedded electric motor 100 may be deteriorated. That is, as the leakage magnetic flux increases, it is necessary to increase the current flowing through the motor. As a result, there is a problem that the loss of the motor increases and the efficiency decreases.

  In the present embodiment, the rotor 90 is a permanent magnet embedded type, and the end shape of the nonmagnetic body portion 9 formed at the circumferential end portion of the magnet insertion hole 5 is the third arc portion 53 (see FIG. 8). ). The 3rd circular arc part 53 is a part of contact circle 11 which contact | connects the linear part 5a of the outer peripheral side end surface of the magnet insertion hole 5 (refer FIG. 8).

  The non-magnetic body portion 9 is disposed so as to be bent toward the output shaft 60 from the outer peripheral surface of the permanent magnet 6 and is disposed so as to be bent toward the output shaft 60 from the inner peripheral surface of the permanent magnet 6. (See FIG. 6).

  If the length of the linear portion 5a on the outer peripheral side end face of the magnet insertion hole 5 is constant and the radius of the third arc portion 53 is changed, the adjacent magnet insertion hole 5 increases as the radius of the third arc portion 53 increases. The circumferential width of the inter-electrode thin portion 12 (see FIG. 8) between the two becomes narrow.

  As will be described later, the strength against the centrifugal force is improved by increasing the radius of the third arc portion 53, but it is set in a range in which the circumferential width of the inter-wall thin portion 12 between the minimum magnet insertion holes 5 is ensured. There is a need to.

  The minimum circumferential width of the thin interelectrode portion 12 between the magnet insertion holes 5 is generally the thickness of one electromagnetic steel sheet (about 0.1 to 1.0 mm) constituting the rotor core 4. is there. When the rotor 90 rotates at a high speed, a centrifugal force acting on the iron core outside the permanent magnet 6 and the magnet insertion hole 5 (a part of the rotor core 4) is also applied to the above-described thin interelectrode portion 12. It is necessary to ensure the strength to withstand.

  Here, the case where the nonmagnetic body portion 9 is an air layer has been described. However, by adopting a method of fixing the permanent magnet 6 by putting an adhesive into the nonmagnetic body portion 9 or a method of injecting (filling) resin. The strength against centrifugal force can be improved, and a highly reliable permanent magnet embedded electric motor 100 can be obtained.

  Moreover, in this Embodiment, as shown in FIG. 8, the circular arc-shaped notch part 8 is provided in a part of q-axis vicinity in the outer periphery shape of the rotor core 4. As shown in FIG. That is, with respect to the first arc portion 41 constituting the outermost peripheral portion of the rotor core 4, the second arc portion 42 having the same center as the center of the first arc portion 41 (coincident with the center of the output shaft 60), A notch 8 is formed.

  The center line (radial direction) of the arc-shaped cutout 8 is substantially coincident with the center line between the poles or the q axis.

  The radius of the second arc portion 42 is smaller than the radius of the first arc portion 41.

  By providing the notch 8, the leakage magnetic flux between the adjacent permanent magnets 6 can be suppressed, so that a highly efficient embedded permanent magnet motor 100 with reduced loss of the motor can be obtained.

  In the present embodiment, the slits 7 are provided in the rotor core 4 disposed outside the outer peripheral surface of the permanent magnet 6. The inside of the slit 7 is a nonmagnetic layer such as a space (air layer) (see FIGS. 7 and 8).

  The slits 7 are provided in the vicinity of the circumferential end surface 6 a of the permanent magnet 6. Between the slit 7 and the magnet insertion hole 5, a slit inner peripheral thin portion 13 (a part of the rotor core 4) is formed. Further, a thin slit outer peripheral portion 73 (see FIG. 9) is formed between the slit 7 and the first arc portion 41.

  By providing the slits 7 in the vicinity of each of the circumferential end surfaces 6a of the permanent magnet 6 on the outer peripheral side of the permanent magnet 6, the leakage magnetic flux between the adjacent permanent magnets 6 is further reduced. Therefore, compared with the case where there is no slit 7, the magnetic flux linked to the stator 80 among the magnetic flux generated by the permanent magnet 6 is increased, so that a more efficient embedded permanent magnet electric motor 100 is obtained. Can do.

The position of the notch 8 will be described with reference to FIG. Points A1, A2, and B1 are defined as follows.
(1) A1 that is on the line of the first arc portion 41 and has the shortest distance (the closest point) between the first arc portion 41 and the magnet insertion hole 5 (third arc portion 53);
(2) The closest point of contact between the first arc portion 41 and the third arc portion 53 is A2;
(3) The intersection of the notch part 8 and the 1st circular arc part 41 is B1.

  In this case, the notch 8 is provided so that B1 is closer to the q-axis side than A1.

  As described above, by providing the third arc portion 53 (see FIG. 8) at the end of the magnet insertion hole 5, the strength of the rotor 90 rotating at high speed against the centrifugal force is ensured. The stress acting on the rotor core 4 due to high-speed rotation tends to be greatest near A1 and A2.

  In the present embodiment, B1 is arranged on the q-axis side with respect to A1, so that it is possible to obtain a highly reliable embedded permanent magnet electric motor 100 that ensures the strength against centrifugal force.

  Here, in FIG. 8, the end of the notch 8 is an edge (corner), but when punching with a mold, an appropriate arc shape (rounding) is provided to reduce the deterioration of the mold. The permanent magnet embedded type electric motor 100 that can be suppressed and has high reliability can be obtained.

  Further, another effect of the notch 8 and the slit 7 will be described. As shown in FIGS. 1 and 6, the direction perpendicular to the permanent magnet 6 (direction in which the magnetic flux flows) is generally defined as the d axis. A position deviated by 90 degrees in electrical angle from the d-axis (that is, a position deviated by 45 degrees in mechanical angle because it has four poles in the present embodiment) is defined as the q-axis.

  By providing the slit 7, the magnetic resistance in the q-axis direction can be increased, and the q-axis inductance can be reduced. Further, by providing the notch portion 8 in the vicinity of the q-axis, the gap 25 between the rotor 90 and the stator 80 is increased in the notch portion 8, so that the q-axis inductance can be reduced.

  The permanent magnet embedded type electric motor 100 of the present embodiment is controlled by a position sensorless 120-degree energization method in which the rotational position of the rotor 90 is not detected by the position sensor. When controlling by the position sensorless 120-degree energization method, the position of the rotor 90 is detected by detecting the voltage (induced voltage) induced in the winding 3 of the stator 80 as the rotor 90 rotates. . That is, an induced voltage appears between terminals of the winding 3 in a non-energized section of 30 degrees with respect to a 120-degree energized section, and the rotational position of the rotor 90 can be detected from the zero cross point of the induced voltage. .

  In the 120-degree energization section, a current flows from the drive circuit (inverter, not shown) to the winding 3 of the stator 80, and it is necessary to commutate the current in the 30-degree non-energization section.

  If the q-axis inductance is large, the current flowing through the winding 3 cannot be reduced quickly, and commutation may not be possible in the 30-degree non-energized section, and the zero cross point of the induced voltage cannot be detected, and the rotational position May not be detected.

  A method for reducing the q-axis inductance can be realized by reducing the number of turns of the winding 3, but if the number of turns of the winding 3 is reduced, when the same torque is output, the current passed through the winding 3 is reduced. Need to be larger.

  Since the copper loss generated in the winding 3 is proportional to the product of the resistance of the winding 3 and the square of the flowing current, when the current increases, the copper loss increases, the motor efficiency decreases and the drive circuit loss decreases. There are increasing challenges.

  In the present embodiment, by providing the notch portion 8 and the slit 7, the q-axis inductance can be reduced without increasing the current flowing through the winding 3. It is possible to obtain a highly efficient embedded permanent magnet motor 100 that can be commutated and can be stably controlled even by a position sensorless 120-degree energization method.

  In general, a position sensorless 120-degree energization driving circuit can be configured at a relatively low cost, so that an inexpensive control device can be obtained.

  Next, a permanent magnet embedded type electric motor 200 of Modification 1 will be described with reference to FIGS. 10 to 14.

  The embedded permanent magnet electric motor 200 of Modification 1 shown in FIG. 10 differs from the embedded permanent magnet electric motor 100 shown in FIG. Since the stator 80 is common, description thereof is omitted.

  11 differs from the rotor 90 of FIG. 6 in the configuration of the slit 107. As shown in FIG. 11, the rotor 190 of Modification 1 has five slits 107 per pole on the outer peripheral side of the permanent magnet 106.

  That is, one slit 107a positioned substantially on the magnetic pole center line, two slits 107b disposed on both sides of the slit 107a, and two slits 107c disposed on the q-axis side of each of the two slits 107b constitute one magnetic pole. Provided.

  One slit 107 a, two slits 107 b, and two slits 107 c have two slits 107 b, so that their extension lines to the outside of the rotor 190 intersect at a point X outside the rotor 190. The two slits 107c are inclined toward the magnetic pole center line. The point X outside the rotor 190 is located, for example, substantially on the magnetic pole center line (see FIG. 12).

  The slit outer peripheral thin part 173 between the slit 107a, the slit 107b, and the slit 107c and the outer periphery (first arc portion 141) of the rotor core 104 is substantially uniform (see FIG. 13).

  The slit inner circumferential thin portion 113 between the slit 107a, the slit 107b, and the slit 107c and the linear portion 105a on the outer peripheral side end surface of the magnet insertion hole 105 is substantially uniform.

  However, the slit outer peripheral thin part 173 and the slit inner peripheral thin part 113 may not be uniform.

  Therefore, the lengths of the slits 107a, 107b, and 107c (substantially in the radial direction) are slit 107a> slit 107b> slit 107c.

  However, the length (substantially in the radial direction) of each slit 107a, slit 107b, and slit 107c does not necessarily satisfy the relationship of slit 107a> slit 107b> slit 107c.

  Compared with the rotor 90 of FIG. 6, the number of slits 107 is increased, and the inside of the slit 107 is a cavity (air layer). Therefore, the weight of the rotor core 104 arranged on the outer peripheral side of the permanent magnet 106 is reduced. When the rotor core 104 disposed on the outer peripheral side of the permanent magnet 106 becomes lighter, when the rotor 190 is operated at the same rotational speed, the centrifugal force is reduced and the stress against the centrifugal force is also reduced (FIG. 11). reference).

  Since the stress with respect to the centrifugal force is low, even if the radius of the third arc portion 153 (see FIG. 14) is increased and the radial dimension of the thin interelectrode portion 112 (see FIG. 14) is reduced, the stress with respect to the centrifugal force is increased. Can be secured. By reducing the radial dimension of the inter-electrode thin portion 112 (see FIG. 14), the leakage magnetic flux can be reduced, and a more efficient embedded permanent magnet electric motor 200 can be obtained.

  On the other hand, when the thickness dimension of the thin electrode portion 112 (see FIG. 14) is set to be the same as that of the rotor 90 of FIG. 6, the rotor 190 with the increased number of slits is compared with the rotor 90 with a smaller number of slits. Thus, since the rotor core 104 disposed on the outer peripheral side of the permanent magnet 106 becomes lighter, the stress against the centrifugal force becomes the same even when the rotor is operated at a higher rotational speed.

  A high rotational speed means that the output of the electric motor becomes high, and a high output embedded permanent magnet electric motor 200 can be obtained. Moreover, when this electric motor is used for a blower, since a high rotation blower can be obtained, a blower with a high air volume can be obtained.

  The notch 108, the nonmagnetic member 109, and the shaft hole 110 of the rotor core 104 of the rotor 190 of the first modification are the notch 8 and nonmagnetic member 9 of the rotor core 4 of the rotor 90. This is the same as the shaft hole 10.

  Next, a permanent magnet embedded type electric motor 300 of Modification 2 will be described with reference to FIGS. 15 to 19.

  15 is different from the embedded permanent magnet motor 100 shown in FIG. 1 in the rotor 290. Since the stator 80 is common, description thereof is omitted.

  The rotor 290 of the second modification shown in FIG. 17 is different in the rotor core 204 from the rotor 90 shown in FIG.

  The rotor core 204 of the modification 2 shown in FIG. 18 differs in the structure of the notch part 208 compared with the rotor core 4 shown in FIG.

  As shown in FIGS. 18 and 19, in the rotor core 204 of Modification 2 shown in FIG. 18, the notch portion 208 has an inner diameter side (shaft hole 210) with respect to the first arc portion 241 that is the outer periphery of the rotor core 204. Side) is configured to have a convex shape (three steps in FIGS. 18 and 19). The three-stage cutout 208 in FIGS. 18 and 19 is an example, and may have any number of stages.

  The stress against the centrifugal force of the outer peripheral thin wall portion between the poles becomes the largest near the point where the third arc portion 253 and the first arc portion 241 are closest (nearest point, point A1 and point A2 in FIG. 19), and the q axis The stress tends to decrease as the value approaches. That is, in the vicinity of the q-axis, the stress against the centrifugal force does not change even if the notch 208 is enlarged toward the inner diameter side.

  On the other hand, from the viewpoint of the q-axis inductance, the gap 225 (see FIG. 16) between the stator 80 and the rotor 290 on the q-axis is widened, so that the q-axis inductance can be further reduced. By reducing the q-axis inductance, stable control can be performed even when control is performed using the position sensorless 120-degree energization method.

  In addition, the magnet insertion hole 205, the permanent magnet 206, the slit 207, the nonmagnetic body portion 209, the inter-electrode thin portion 212, and the output shaft 260 of the rotor core 204 of the rotor 290 of the modified example 2 are rotated by the rotor 90. This is the same as the magnet insertion hole 5, the permanent magnet 6, the slit 7, the nonmagnetic part 9, the inter-electrode thin part 12, and the output shaft 60 of the core 4.

  Next, an embedded permanent magnet electric motor 400 according to Modification 3 will be described with reference to FIGS.

  A permanent magnet embedded type electric motor 400 of Modification 3 shown in FIG. 20 is different in a rotor 390 from the permanent magnet embedded type electric motor 100 shown in FIG. Since the stator 80 is common, description thereof is omitted.

  The rotor 390 of the modification 3 shown in FIG. 21 differs in the rotor core 304 compared with the rotor 90 shown in FIG.

  22 is different from the rotor core 4 shown in FIG. 7 in the configuration of the slits 307.

  The slit 307 of the rotor core 304 of the modification 3 is a side closer to the d axis in the radial width dimension of the slit outer peripheral thin portion 373 that is the thin portion of the rotor core 304 configured on the outer peripheral portion of the slit 307 in the radial direction. In contrast, the width closer to the q-axis is increased.

  As shown in FIGS. 23 and 24, the radial width dimension of the slit outer peripheral thin portion 373 formed in the radial outer peripheral portion of the slit 307 is larger on the q-axis side than on the d-axis side.

That is, the radial width dimension on the side close to the d-axis side between the outer periphery (first arc portion 341) and the slit 307 of the rotor core 304 is Wd, and the outer periphery (first arc portion 341) and the slit 307 of the rotor core 304 are. If the radial width dimension on the side close to the q-axis side is Wq,
Wq> Wd
There is a relationship.

  Centrifugal force due to high-speed rotation of the rotor core 304 generates a large stress in the slit outer peripheral thin portion 373 on the side close to the q axis.

  Although it is possible to suppress stress against centrifugal force by uniformly increasing the radial width dimension of the slit outer peripheral thin portion 373, the q-axis inductance increases, so that the position sensorless 120 degree energization method is stable. It becomes difficult to control.

  Here, the increase in the q-axis inductance can be suppressed by making the radial width dimension Wd closer to the d-axis smaller than the radial width dimension Wq closer to the q-axis. Thereby, the permanent magnet embedded type electric motor 400 that can be stably controlled even by the position sensorless 120-degree energization method can be obtained.

  When the slit 307 is punched with a mold, it is necessary to provide appropriate rounding (R shape) at each vertex of the slit 307 in order to suppress deterioration of the mold. In the present embodiment, the radius R2 of the rounding 372 closer to the q axis is set larger than the radius R1 of the rounding 371 closer to the d axis at the outer peripheral apex of the slit 307 (see FIG. 25).

  As described above, the stress acting on the slit outer peripheral thin portion 373 due to the centrifugal force is larger on the side closer to the q axis (the rounding 372 side), but in this embodiment, the radius R2 of the rounding 372 is set to the rounding 371. By making it larger than the radius R1, it is possible to obtain a highly reliable embedded permanent magnet electric motor 400 in which stress against centrifugal force is suppressed.

  Further, in the enlarged view of the vicinity of the inter-pole portion (q-axis) of the rotor core 304 in FIG. 26, the radially outer peripheral side of the magnet insertion hole 305 is composed of a straight portion 305a and a third arc portion 353, These are part of the tangent circle 311 in contact with the straight line portion 305a, and each point is an intersection.

  Since the third arc portion 353 is a tangent circle of the straight portion 305a, each is smoothly connected (connected), and therefore stress against centrifugal force can be suppressed.

  The third arc portion 353 is in contact with the fourth arc portion 354 at the point D, and the point D is an intersection. When the point where the distance between adjacent magnet insertion holes 305 is closest (the closest point) is point C, the point D is configured to approach the shaft hole 310 with respect to the point C (see FIG. 11).

  When the rotor 390 rotates at a high speed, stress against centrifugal force is generated in the inter-electrode thin portion 312 formed between the adjacent magnet insertion holes 305, and the circumferential width dimension of the inter-electrode thin portion 312 is too small. In the worst case, the rotor 390 may break during high-speed rotation.

  Further, when the intersection D of the third arc portion 353 and the fourth arc portion 354 is brought close to the outer peripheral side of the rotor core 304, a large stress is generated at the point D (see the comparative example of FIG. 27). In the embodiment, by providing the point D on the inner diameter side (side closer to the shaft hole 310) with respect to the point C (inter-electrode thin portion 412), the stress with respect to centrifugal force is relieved, and a highly reliable permanent magnet embedded A built-in electric motor 400 can be obtained.

  In addition, the permanent magnet 306, the notch 308, and the non-magnetic part 309 of the rotor core 304 of the rotor 390 of the modification 3 are the permanent magnet 6, the notch 8, and the non-magnetic part 309 of the rotor core 4 of the rotor 90. This is the same as the magnetic part 9.

  Further, the magnet insertion hole 405, the straight portion 405 a, the slit 407, the inter-electrode thin portion 412, and the third arc portion 453 of the rotor core 404 of the comparative example are the same as the magnet insertion hole 5 of the rotor core 4 of the rotor 90. These are the same as the straight line part 5 a, the slit 7, the inter-electrode thin part 12, and the third arc part 53.

  In the above-described embodiment, for example, the embedded permanent magnet electric motor 100 has been shown in which the rotor core 4 disposed outside the outer peripheral surface of the permanent magnet 6 is provided with the slit 7, but there is no slit 7. May be. The same applies to other modified examples.

  A high performance blower can be obtained by mounting the permanent magnet embedded motors 100 to 400 of the present embodiment on the blower. In that case, the blades of the blower are fixed to the rotors of the permanent magnet embedded motors 100 to 400.

  As an application example of the present invention, there is an embedded permanent magnet electric motor used for a blower.

  DESCRIPTION OF SYMBOLS 1 Stator iron core, 3 windings, 4 Rotor iron core, 5 Magnet insertion hole, 5a Linear part, 6 Permanent magnet, 6a Circumferential end surface, 7 Slit, 8 Notch part, 9 Nonmagnetic part, 10 Axis hole, 11 Tangent circle, 12 pole thin part, 13 slit inner thin part, 21 tooth part, 21a tip part, 22 slot, 22a slot opening part, 23 core back, 25 gap, 41 first arc part, 42 second arc part , 51 Permanent magnet retaining part, 53 Third arc part, 60 Output shaft, 73 Slit outer peripheral thin part, 80 Stator, 90 Rotor, 100 Permanent magnet embedded motor, 104 Rotor core, 105 Magnet insertion hole, 105a Straight part, 106 permanent magnet, 107 slit, 107a slit, 107b slit, 107c slit, 108 notch part, 109 non-magnetic part, 110 axial hole, 1 2 Thin part between electrodes, 113 Thin part inside slit, 141 First arc part, 153 Third arc part, 160 Output shaft, 173 Thin part around slit outer circumference, 190 rotor, 200 embedded permanent magnet electric motor, 204 rotor Iron core, 205 Magnet insertion hole, 206 Permanent magnet, 207 Slit, 208 Notch, 209 Non-magnetic part, 210 Shaft hole, 212 Thin part between the poles, 225 Air gap, 241 First arc part, 253 Third arc part, 260 Output shaft, 290 rotor, 300 permanent magnet embedded motor, 304 rotor core, 305 magnet insertion hole, 305a linear portion, 306 permanent magnet, 307 slit, 308 notch, 309 non-magnetic body portion, 310 shaft hole, 311 tangent circle, 312 thin portion between poles, 353 third arc portion, 354 fourth arc portion, 360 output shaft, 371 rounding, 372 Rounding, 373 Slit outer peripheral thin part, 390 Rotor, 400 Permanent magnet embedded motor, 404 Rotor core, 405 Magnet insertion hole, 405a Linear part, 407 Slit, 412 Thin part between poles, 453 Third arc part, 454 Fourth arc portion.

Claims (7)

A permanent magnet embedded controlled by a position sensorless 120-degree energization method in which a rotor is disposed through a gap inside a stator in which a winding is wound on a stator core, and the rotational position of the rotor is not detected by a position sensor. Type motor,
The rotor is
A rotor core constructed by laminating a plurality of thin electromagnetic steel sheets;
A plurality of magnet insertion holes that are provided along the outer peripheral edge of the rotor core and that have a substantially U-shape as a whole and have arc-shaped non-magnetic parts bent at both ends in the circumferential direction;
A plurality of permanent magnets embedded in the magnet insertion hole;
Provided in a part of the rotor core disposed on the outer peripheral side of the permanent magnet, and comprising a slit made of a non-magnetic layer,
The non-magnetic body portion is configured to be arranged on the inner side of the outer peripheral side surface of the permanent magnet, and is formed to extend to the inner diameter side of the inner peripheral side surface of the permanent magnet. Permanent magnet embedded motor.   2. The embedded permanent magnet electric motor according to claim 1, wherein the slit is provided at least in the vicinity of both end portions of the permanent magnet.   The radial width dimension of the thin slit outer peripheral portion of the rotor core formed on the outer peripheral side of the slit is larger in the radial width dimension on the q-axis side than the radial width dimension on the d-axis side. The embedded permanent magnet electric motor according to claim 1 or 2. A permanent magnet embedded controlled by a position sensorless 120-degree energization method in which a rotor is disposed through a gap inside a stator in which a winding is wound on a stator core, and the rotational position of the rotor is not detected by a position sensor. Type motor,
The rotor is
A rotor core constructed by laminating a plurality of thin electromagnetic steel sheets;
A plurality of magnet insertion holes that are provided along the outer peripheral edge of the rotor core and that have a substantially U-shape as a whole and have arc-shaped non-magnetic parts bent at both ends in the circumferential direction;
A plurality of permanent magnets embedded in the magnet insertion hole,
The non-magnetic body portion is configured to be arranged on the inner side of the outer peripheral side surface of the permanent magnet, and is formed to extend to the inner diameter side of the inner peripheral side surface of the permanent magnet. Permanent magnet embedded motor.   The embedded permanent magnet electric motor according to any one of claims 1 to 4, wherein a convex cutout portion is provided on an outer peripheral edge in the vicinity of the q-axis of the rotor core.   6. The embedded permanent magnet electric motor according to claim 5, wherein the notch is provided so as to have a most convex shape inward on the q axis.   A blower comprising: the embedded permanent magnet electric motor according to any one of claims 1 to 6; and a blade fixed to the rotor of the embedded permanent magnet electric motor.

Images