JP2012139068A - Rotor for embedded magnet type motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor of an embedded magnet type motor that can improve reluctance torque at the time of weak field operation in a high speed area and that is strong in demagnetization.SOLUTION: In the rotor of an embedded magnet type motor, a permanent magnet is embedded in a rotor core. The rotor core includes a plurality of magnet insertion holes formed along the outer circumference edge and magnet insertion parts that are formed in almost central parts of the respective magnet insertion holes, into each of which a permanent magnet is inserted with a predetermined gap. The cross section shape of the permanent magnet and magnet insertion part has a configuration as follows: a. the cross section of the rotor core outer circumference part side of the permanent magnet and magnet insertion part is a shape whose central part is inwardly recessed and the recess is formed into an almost rectangular shape; and b. the cross section of the opposite side to the rotor core outer circumference part of the permanent magnet and magnet insertion part is almost linear.

Description

  The present invention relates to a rotor of an embedded magnet type motor.

  When a terminal voltage is applied to an embedded magnet type motor (IPM), a current corresponding to the difference voltage between the terminal voltage and an induced voltage (Vf) generated by the interlinkage magnetic flux of the permanent magnet embedded in the rotor flows at a low speed. Can generate large torque. However, since this induced voltage (Vf) increases in proportion to the rotation speed, when the applied terminal voltage is constant, Vf increases as the number of rotations is increased, and Vf eventually becomes almost equal to the terminal voltage. If they are equal, current will not flow, and the motor will not be able to run any further (voltage saturation).

The terms used in this specification are defined.
(1) Embedded magnet type motor: Sometimes referred to simply as a motor.
(2) Stator: Also called a stator.
(3) Core: Also called iron core.
(4) Rotor: Also called rotor.
(5) Magnet: Also called a permanent magnet.

  The motor output P is obtained from the rotational speed ω, torque τ, and electrical frequency f as follows.

If the current stops flowing due to voltage saturation, the torque τ generated by the motor becomes small, and the constant output cannot be maintained. To solve this problem, there are the following methods.
(1) Increase the terminal voltage applied to the motor.
(2) Lower the induced voltage (Vf).

  Among these, as a method for lowering the latter (2) induced voltage (Vf), for example, the following magnetic synchronous machine has been proposed. In order to provide a magnet type synchronous machine with improved flux-weakening control capability during high-speed rotation, this magnetic type synchronous machine has a rotor in which a permanent magnet is fixed to the peripheral surface of a soft magnetic rotor core, and the peripheral surface of the rotor. A permanent magnet, which is magnetized in the radial direction as rotor magnetic poles and alternately arranged in the circumferential direction as a rotor magnetic pole. The machine has a soft magnetic salient pole portion that is located in the circumferential central portion of the permanent magnet constituting one rotor magnetic pole and projects from the circumferential surface of the rotor core toward the gap.

  According to this magnet type synchronous machine, the salient pole part protruding toward the stator core side through the thinned permanent magnet forming one rotor magnetic pole increases the d-axis inductance Ld. At the time, the -d-axis current Id is energized to increase the -d-axis current magnetic flux Φid, and the weak magnetic flux control to reduce the combined d-axis magnetic flux (the sum of the magnet magnetic flux Φm and the d-axis current magnetic flux Φid). It can be realized with a small amount of d-axis current (see, for example, Patent Document 1).

JP 2009-1331070 A

  In Patent Document 1, salient pole portions extending in the axial direction are provided between the magnetic poles of a plurality of magnets arranged on the rotor surface. With this configuration, the reluctance torque in the field weakening is improved by making the d-axis inductance Ld larger than the q-axis inductance Lq. However, since the torque generated by the surface magnet type motor is a magnet torque, it can be said that the effect of improving the reluctance torque by installing the salient pole portion is small.

  The present invention has been made to solve the above-described problems, and can improve the reluctance torque during field-weakening operation at high speeds while expanding the motor operating range, and is also resistant to demagnetization. Provided is a rotor for an embedded magnet type motor.

The rotor of the embedded magnet type motor according to the present invention is a rotor of an embedded magnet type motor in which a permanent magnet is embedded inside the rotor core,
The rotor core includes a plurality of magnet insertion holes formed along the outer peripheral edge,
A magnet insertion part formed at a substantially central part of the magnet insertion hole, into which a permanent magnet is inserted with a predetermined gap,
The permanent magnet and the magnet insertion portion are characterized in that the cross-sectional shape is as follows.
a. The cross section of the permanent magnet and the magnet insertion part on the outer side of the outer periphery of the rotor core has a shape in which a central part is recessed inward, and the recessed part is formed in a substantially rectangular shape;
b. The cross section of the permanent magnet and the magnet insertion part on the opposite side of the outer periphery of the rotor core is substantially straight.

  The rotor of the embedded magnet type motor according to the present invention has an operation limit speed at which the d-axis inductance Ld and the q-axis inductance Lq are improved and the motor can be operated with respect to a generally used flat magnet by the above configuration. This improves the reluctance torque during field-weakening operation and improves the motor output. Further, since the width of the magnet end is increased, the local demagnetization resistance can be improved.

It is a figure shown for a comparison and sectional drawing of the rotor 500 of a general embedded magnet type | mold motor. It is a figure shown for a comparison and sectional drawing of the rotor core 510 of the rotor 500 of a general embedded magnet type | mold motor. It is a figure shown for a comparison and the enlarged view of the magnet insertion hole 511. FIG. The figure shown for a comparison, The figure which shows the state which generates the magnetic flux which generate | occur | produces from a stator in the direction which negates the magnetic flux of the permanent magnet 512 by advancing the phase of the electric current which flows into a stator. It is a figure shown for a comparison and is a fragmentary sectional view which shows the d-axis direction and the q-axis direction of the rotor 500. The elements on larger scale of FIG. FIG. 3 shows the first embodiment and is a cross-sectional view of the rotor 100 of the embedded magnet type motor. FIG. 3 shows the first embodiment, and is a cross-sectional view of a rotor core 110 of a rotor 100 of an embedded magnet type motor. FIG. 5 shows the first embodiment and is an enlarged view of a magnet insertion hole 111. The elements on larger scale of FIG. FIG. 5 is a partial cross-sectional view showing the first embodiment and showing a d-axis direction and a q-axis direction of the rotor 100. FIG. 5 shows the first embodiment and shows a d-axis inductance (comparative example, this embodiment) obtained by the Dalton-Cameron method. The figure which shows Embodiment 1 and shows the q-axis inductance (comparative example, this Embodiment) calculated | required by the Dalton-Cameron method. FIG. 5 shows the first embodiment, and shows a voltage between terminals when a phase is advanced. FIG. 5 shows the first embodiment, and is a cross-sectional view of a rotor 200 of a first modification. FIG. 5 shows the first embodiment, and is a cross-sectional view of a rotor core 210 of a rotor 200 of a first modification. FIG. 5 shows the first embodiment and is an enlarged view of a magnet insertion hole 211. FIG. 5 shows the first embodiment and is a cross-sectional view of a rotor 300 of a second modification. FIG. 5 shows the first embodiment, and is a cross-sectional view of a rotor core 310 of a rotor 300 of a second modification. FIG. 5 shows the first embodiment and is an enlarged view of a magnet insertion hole 311.

Embodiment 1 FIG.
FIG. 1 is a view for comparison, and is a cross-sectional view of a rotor 500 of a general embedded magnet type motor. Before describing the rotor of the embedded magnet type motor according to the present embodiment, a general rotor 500 of the embedded magnet type motor will be described. The embedded magnet type motor is a so-called brushless DC motor.

  As shown in FIG. 1, a rotor 500 of a general embedded magnet type motor has a rotor core 510 and a plurality of (here, 6) embedded in predetermined locations (magnet insertion holes 511) of the rotor core 510. ) Permanent magnets 512. Adjacent permanent magnets 512 have opposite magnetization directions.

  The rotor 500 is disposed inside a stator (not shown) via a gap having a predetermined radial dimension. When an alternating current is passed through the coil wound around the teeth portion of the stator, a rotating magnetic field is generated in the stator, thereby generating torque and rotating the rotor 500.

  The rotor 500 constitutes a six-pole rotor by six permanent magnets 512.

  FIG. 2 is a view for comparison, and is a cross-sectional view of a rotor core 510 of a rotor 500 of a general embedded magnet type motor. The rotor core 510 is manufactured by punching out electromagnetic steel sheets having a thickness of about 0.1 to 1.5 mm into a predetermined shape, stacking a predetermined number of sheets in the axial direction, and fixing by punching or welding. The entire rotor core 510 is substantially cylindrical, and a plurality (six in this case) of magnet insertion holes 511 are formed along the outer peripheral edge so as to form a substantially hexagonal shape. A shaft hole 513 (having a circular cross section) is formed in the center portion of the rotor core 510 into which a rotation shaft (not shown) is inserted.

  FIG. 3 is a view for comparison, and is an enlarged view of the magnet insertion hole 511. The magnet insertion hole 511 has a substantially rectangular cross section. The central part of the magnet insertion hole 511 is a magnet insertion part 511a for inserting the permanent magnet 512, and both sides of the magnet insertion part 511a are magnetic flux leakage suppression parts 511b. The magnetic flux leakage suppression unit 511b is a space.

  The voltage equation of the motor can be expressed as follows:

  Thus, the voltage generated by the motor is determined by the winding resistance, inductance, and induced voltage (Vf) due to the flux linkage. When the rotational speed is increased, the induced voltage rises, eventually the difference between the terminal voltage and the induced voltage disappears, and the rotational speed cannot be increased any more (voltage saturation). Therefore, in order to rotate at a higher speed, it is necessary to increase the voltage between terminals or decrease the induced voltage.

  FIG. 4 is a diagram for comparison, and shows a state in which the magnetic flux generated from the stator is generated in the direction to cancel the magnetic flux of the permanent magnet 512 by advancing the phase of the current flowing through the stator. A field weakening is a general method for suppressing the voltage saturation and lowering the latter induced voltage. By advancing the phase of the current flowing through the stator, the magnetic flux generated from the stator is generated in a direction that cancels the magnetic flux of the permanent magnet 512, thereby reducing the induced voltage and suppressing voltage saturation (FIG. 4).

Assuming that the current flowing through the motor is _Ia , Equations (3) to (5) are established, and when this is substituted into Equation (2), Equation (6) is obtained.

By advancing the phase in this way, ωL _d I _a sin β increases to minus, and the voltage between terminals decreases, so that high output can be achieved.

  Next, the equations for generated torque and limit operating speed are shown below.

From the equation (7), the torque generated in the motor has a term Ψ _a i _q caused by magnet torque and a term (L _q −L _d ) i _d i _q caused by reluctance torque. While the reluctance torque is determined by the difference between the inductance (Lq-Ld), (8 ) To increase the operating limit speed omega _c of flux-weakening control than expression, or to reduce the [psi _a, it is either increased Ld.

[Psi _a is to affect the magnet torque, it is undesirable to reduce the [psi _a. Therefore, it is necessary to increase Ld. However, since the reluctance torque determined by the difference in inductance (Ld−Lq) decreases, it is desirable to increase Lq while increasing Ld.

  FIG. 5 is a view for comparison, and is a partial cross-sectional view showing the d-axis direction and the q-axis direction of the rotor 500. As shown in FIG. 5, the inductance includes an inductance in the d-axis direction, which is the pole center of the rotor 500, and an inductance in the q-axis direction, which is at a position shifted from the d-axis by 90 degrees in the circumferential direction by an electrical angle. . Ld and Lq indicate the ease of passage of magnetic flux in the d-axis direction and the q-axis direction, respectively.

  When the magnetic flux passes through the magnetic steel sheet having a high magnetic permeability, the inductance L increases, and conversely, in the insulating portion having a low magnetic permeability such as air, the magnetic flux does not easily pass through and the inductance L becomes small.

FIG. 6 is a partially enlarged view of FIG. As shown in FIG. 6, the dimension of each part is defined as follows.
(1) The radial width of the magnet insertion hole 511 (permanent magnet 512) is T;
(2) The distance between the magnet insertion hole 511 (permanent magnet 512) and the outer periphery of the rotor core 510 on the pole center line is h;
(3) The width in the circumferential direction of the magnet insertion portion 511a (permanent magnet 512) is W.

  To increase Ld, the radial width T of the magnet insertion hole 511 (permanent magnet 512) is reduced, and to increase Lq, the magnet insertion hole 511 (permanent magnet 512) and the rotor core on the pole center line are increased. It is desirable to increase the distance h from the outer periphery of 510 (see FIG. 6).

  If the cross-sectional area of the permanent magnet 512 is S, S can be represented by T × W.

  FIG. 7 shows the first embodiment, and is a cross-sectional view of the rotor 100 of the embedded magnet type motor. The rotor 100 shown in FIG. 7 is characterized in that both the d-axis inductance Ld and the q-axis inductance Lq are increased. There is a feature in the cross-sectional shape of the magnet insertion hole 111 (permanent magnet 112).

  As with the rotor 500 of the comparative example, the rotor 100 of the embedded magnet type motor has a rotor core 110 and a plurality of (here, six) cores embedded in predetermined locations (magnet insertion holes 111) of the rotor core 110. ) Permanent magnet 112. Adjacent permanent magnets 112 have opposite magnetization directions.

  The rotor 100 is disposed inside a stator (not shown) via a gap having a predetermined radial dimension. When an alternating current is passed through a coil wound around the teeth portion of the stator, a rotating magnetic field is generated in the stator, thereby generating torque and rotating the rotor 100.

  The rotor 100 includes a six-pole rotor by six permanent magnets 112.

  FIG. 8 shows the first embodiment and is a cross-sectional view of the rotor core 110 of the rotor 100 of the embedded magnet type motor. The rotor core 110 is manufactured by punching a magnetic steel sheet having a thickness of about 0.1 to 1.5 mm into a predetermined shape, laminating a predetermined number of sheets in the axial direction, and fixing by punching or welding. The entire rotor core 110 is substantially cylindrical, and a plurality (six in this case) of magnet insertion holes 111 are formed in a substantially hexagonal shape along the outer peripheral edge. A shaft hole 113 (having a circular cross section) is formed in the center of the rotor core 110 into which a rotation shaft (not shown) is inserted.

  FIG. 9 shows the first embodiment and is an enlarged view of the magnet insertion hole 111. The magnet insertion hole 111 has a substantially rectangular cross section. A central portion of the magnet insertion hole 111 is a magnet insertion portion 111 a into which the permanent magnet 112 is inserted. The cross section of the magnet insertion part 111a has a shape in which the outer peripheral part of the rotor is recessed inward. The shape of the recess is substantially rectangular and is symmetric with respect to the pole center. The rotor inner peripheral part side of the cross section of the magnet insertion part 111a is substantially linear.

  Both sides of the magnet insertion portion 111a are magnetic flux leakage suppression portions 111b. The magnetic flux leakage suppression unit 111b is a space.

FIG. 10 is a partially enlarged view of FIG. Here, the dimension of each part of the permanent magnet 112 is defined.
(1) The thickness of the central portion of the permanent magnet 112 is T1;
(2) The thickness of both ends of the permanent magnet 112 is T2;
(3) The circumferential length T3 of the central portion of the permanent magnet 112;
(4) The circumferential length T4 (= W) of the permanent magnet 112 (magnet insertion portion 111a).

  The sectional area S1 of the permanent magnet 112 is made equal to the sectional area S of the permanent magnet 512 of the comparative example. The cross-sectional area S1 of the permanent magnet 112 can be expressed by the following equation (9).

  The thickness T2 of the both ends of the permanent magnet 112 is larger than the radial width T of the magnet insertion hole 511 (permanent magnet 512) of the comparative example (T2> T). The permanent magnet 112 is characterized in that the thickness T1 at the center is smaller than the thickness T2 at both ends. And the rotor outer peripheral side of the permanent magnet 112 becomes concave inside, and the cross section inside the permanent magnet 112 is a straight line.

  FIG. 11 shows the first embodiment and is a partial cross-sectional view showing the d-axis direction and the q-axis direction of the rotor 100. By making the shape of the permanent magnet 112 as described above, the radial width T1 of the permanent magnet 112 (magnet insertion hole 111) in the d-axis direction is smaller than T in the comparative example, as shown in FIG. As a result, the d-axis inductance Ld increases. In the q-axis direction, a magnetic path on the outer periphery of the rotor is secured, and the q-axis inductance Lq is also increased.

  FIGS. 12 and 13 are diagrams showing the first embodiment, FIG. 12 is a diagram showing d-axis inductance (comparative example, this embodiment) obtained by the Dalton-Cameron method, and FIG. 13 is obtained by the Dalton-Cameron method. It is a figure which shows q-axis inductance (a comparative example, this Embodiment).

  The inductances of the rotor 500 in FIG. 1 and the rotor 100 in FIG. 7 were obtained by analysis by the Dalton-Cameron method. The results are shown in FIGS. For comparison, both induced voltages Vf are analyzed under the same conditions. From this, it can be confirmed that the rotor 100 of the present embodiment is improved in both the d-axis inductance Ld and the q-axis inductance Lq with respect to the rotor 500 (basic shape).

  FIG. 14 is a diagram illustrating the first embodiment, and is a diagram illustrating a voltage between terminals when the phase is advanced. FIG. 14 shows the relationship between the terminal voltage and the current phase under the same conditions. By improving the d-axis inductance Ld, it can be confirmed that the voltage between the terminals of the rotor 100 of the present embodiment is reduced with respect to the rotor 500 (basic shape) of FIG. Further, since the q-axis inductance Lq is also improved, it can be seen from the equation (7) that the reduction of the reluctance torque due to the increase of the d-axis inductance Ld can be suppressed.

  From the above results, the permanent magnet 112 inserted into the rotor 100 has a thickness T1 at the central portion smaller than the thickness T2 at both ends, and the outer peripheral side of the rotor of the permanent magnet 112 is recessed inward, so that the permanent magnet 112 By adopting a configuration in which the cross section is a straight line, the d-axis inductance Ld and the q-axis inductance Lq are improved, and the reduction of the reluctance torque due to the increase of the d-axis inductance Ld can be suppressed.

  In the above-described weak magnetic flux control, the magnetic phase of the permanent magnet is canceled by advancing the current phase to lower the terminal voltage and achieve high speed and high torque. At this time, if the current flowing through the stator winding is large, the permanent magnet There is a risk of demagnetization. Therefore, a structure that does not demagnetize the permanent magnet in the field weakening is important.

  In the embedded magnet type motor, the permanent magnet is embedded in the rotor core, so that the demagnetization resistance is relatively large. However, when concentrated winding is used for the stator, the adjacent teeth of the stator are located at different locations, so that a magnetic circuit with a high magnetic flux density is formed at the tip of the stator teeth, resulting in local reduction. Magnetism easily occurs. In particular, local demagnetization may occur in a portion near the rotor surface of the permanent magnet.

  In order to increase the demagnetization resistance, there are methods of using a permanent magnet having a high holding force, moving the permanent magnet position from the vicinity of the outer periphery of the rotor to the inner periphery, or increasing the magnet thickness. However, if a permanent magnet having a high holding force is used, the cost is increased or the residual magnetic flux density is lowered, and if the permanent magnet is moved toward the inner periphery of the rotor, the magnetic force of the rotor is lowered.

  Therefore, as shown in FIG. 10, by making the thickness T2 of the end portion of the permanent magnet 112 larger than the thickness T1 of the center portion of the permanent magnet 112, local demagnetization that occurs at the end portion of the permanent magnet 112 is suppressed. can do.

  FIG. 15 is a diagram illustrating the first embodiment, and is a cross-sectional view of the rotor 200 of the first modification. The feature of the rotor 200 of Modification 1 is that the permanent magnet 212 has a cross-sectional shape in which the magnet thickness gradually decreases from the magnet end toward the center.

  As in the case of the rotor 100, the rotor 200 according to the first modified example has a rotor core 210 and a plurality (six in this case) of permanent magnets embedded in predetermined locations (magnet insertion holes 211) of the rotor core 210. 212. Adjacent permanent magnets 212 have opposite magnetization directions.

  The rotor 200 is disposed inside a stator (not shown) via a gap having a predetermined radial dimension. When an alternating current is passed through a coil wound around the teeth portion of the stator, a rotating magnetic field is generated in the stator, thereby generating torque and rotating the rotor 200.

  The rotor 200 constitutes a six-pole rotor by six permanent magnets 212.

  FIG. 16 is a diagram showing the first embodiment, and is a cross-sectional view of the rotor core 210 of the rotor 200 of the first modification. The rotor core 210 is manufactured by punching a magnetic steel sheet having a thickness of about 0.1 to 1.5 mm into a predetermined shape, then stacking a predetermined number of sheets in the axial direction, and fixing by punching or welding. The entire rotor core 210 is substantially cylindrical, and a plurality of (here, six) magnet insertion holes 211 are formed in a substantially hexagonal shape along the outer peripheral edge. A shaft hole 213 (a cross section is circular) into which a rotation shaft (not shown) is inserted is formed at the center of the rotor core 210.

  FIG. 17 shows the first embodiment and is an enlarged view of the magnet insertion hole 211. The magnet insertion hole 211 has a substantially bathtub-shaped cross section. A central portion of the magnet insertion hole 211 is a magnet insertion portion 211 a into which the permanent magnet 212 is inserted. The cross section of the magnet insertion portion 211a has a shape in which the rotor outer peripheral side is concave inward. The shape of the concave portion is a substantially triangular shape having the polar center as a vertex, and is symmetric with respect to the polar center. The rotor inner peripheral part side of the cross section of the magnet insertion part 211a is substantially linear.

  Both sides of the magnet insertion portion 211a are magnetic flux leakage suppression portions 211b. The magnetic flux leakage suppression unit 211b is a space.

  FIG. 18 is a diagram illustrating the first embodiment, and is a cross-sectional view of a rotor 300 of a second modification. The feature of the rotor 300 of the second modification is that the cross-sectional shape of the permanent magnet 312 gradually decreases from the end of the magnet (between the poles) toward the center of the pole, and the permanent magnet 312 is further reduced at the center of the pole. The point is that it is divided.

  Similar to the rotor 100, the rotor 300 according to the second modified example includes a rotor core 310 and a plurality of (here, 12) permanent magnets embedded in predetermined locations (magnet insertion holes 311) of the rotor core 310. 312. The pair of adjacent permanent magnets 312 have opposite magnetization directions.

  The rotor 300 is disposed inside a stator (not shown) via a gap having a predetermined radial dimension. When an alternating current is passed through the coil wound around the teeth portion of the stator, a rotating magnetic field is generated in the stator, thereby generating torque and rotating the rotor 300.

  The rotor 300 constitutes a six-pole rotor by twelve permanent magnets 312.

  FIG. 19 shows the first embodiment, and is a cross-sectional view of the rotor core 310 of the rotor 300 of the second modification. The rotor core 310 is manufactured by punching a magnetic steel sheet having a thickness of about 0.1 to 1.5 mm into a predetermined shape, then laminating a predetermined number of sheets in the axial direction, and fixing by punching or welding. The entire rotor core 310 is substantially cylindrical, and a plurality of (here, 12) magnet insertion holes 311 are formed along the outer peripheral edge so as to form a substantially hexagonal shape. A shaft hole 313 (having a circular cross section) into which a rotation shaft (not shown) is inserted is formed at the center of the rotor core 310.

  FIG. 20 shows the first embodiment and is an enlarged view of the magnet insertion hole 311. Two magnet insertion holes 311 are arranged symmetrically with respect to one magnetic pole. Each of the magnet insertion holes 311 has a magnet insertion portion 311a for inserting the permanent magnet 312 on the pole center side and a magnetic flux leakage suppression portion 311b on the interpolar side. The magnetic flux leakage suppression unit 311b is a space.

  The magnet insertion portion 311a has a cross-sectional shape in which the radial width gradually decreases from the gap to the pole center. The magnet insertion portion 311a includes two magnet insertion holes 311 that are arranged symmetrically with respect to one magnetic pole. A recess is formed on the side. The rotor inner peripheral side of the two magnet insertion holes 311 arranged symmetrically with respect to one magnetic pole has a substantially linear cross section.

  The rotor 200 of the first modification example and the rotor 300 of the second modification example have the same effects as the rotor 100.

  DESCRIPTION OF SYMBOLS 100 Rotor, 110 Rotor core, 111 Magnet insertion hole, 111a Magnet insertion part, 111b Magnetic flux leak suppression part, 112 Permanent magnet, 113 axial hole, 200 Rotor, 210 Rotor core, 211 Magnet insertion hole, 211a Magnet insertion Part 211b magnetic flux leakage suppression part 212 permanent magnet 213 shaft hole 300 rotor rotor 310 rotor core 311 magnet insertion hole 311a magnet insertion part 311b magnetic flux leakage suppression part 312 permanent magnet 313 shaft hole 500 Rotor, 510 Rotor core, 511 Magnet insertion hole, 511a Magnet insertion part, 511b Magnetic flux leakage suppression part, 512 Permanent magnet, 513 Shaft hole.

Claims (2)

A rotor of an embedded magnet type motor in which a permanent magnet is embedded inside the rotor core,
The rotor core includes a plurality of magnet insertion holes formed along the outer periphery,
A magnet insertion part formed at a substantially central part of the magnet insertion hole, into which the permanent magnet is inserted with a predetermined gap,
The permanent magnet and the magnet insertion part have a cross-sectional shape configured as shown below, and a rotor of an embedded magnet type motor,
a. The cross section of the permanent magnet and the magnet insertion part on the outer side of the outer periphery of the rotor core has a shape in which a central part is recessed inward, and the recessed part is formed in a substantially rectangular shape;
b. The cross section of the permanent magnet and the magnet insertion part on the opposite side of the outer periphery of the rotor core is substantially straight.   The rotor of an embedded magnet type motor according to claim 1, wherein the magnet insertion hole includes a magnetic flux leakage suppression portion on both sides of the magnet insertion portion.

Images