JP6316601B2 - Rotor and permanent magnet motor - Google Patents

Description

  The present invention relates to a rotor provided with a permanent magnet and a permanent magnet motor provided with a rotor provided with a permanent magnet, and in particular, to improve the efficiency of the permanent magnet motor while using a ferrite magnet as the permanent magnet. It relates to the technology that can.

As a permanent magnet provided in a rotor of a permanent magnet motor, a rare earth magnet such as a neodymium magnet having a high residual magnetic flux density is used. However, rare earth magnets are expensive. For this reason, the use of a ferrite magnet or the like that is less expensive than a rare earth magnet is desired.
As a permanent magnet motor including a rotor using a ferrite magnet, for example, a permanent magnet motor disclosed in Patent Document 1 is known. The permanent magnet motor disclosed in Patent Document 1 uses a rotor having a rotor core 600 shown in FIG. FIG. 10 is a cross-sectional view of the rotor core 600 viewed from a direction perpendicular to the axial direction. The rotor core 600 shown in FIG. 10 has a plurality of magnet insertion holes 611 extending linearly along the q axis from the rotation center O of the rotor core 600 along the circumferential direction. A permanent magnet 621 extending linearly is inserted into the magnet insertion hole 611. A ferrite magnet is used as the permanent magnet 621. The magnet insertion hole 611 and the permanent magnet 621 have a quadrangular cross section.

JP 2010-4722 A

Ferrite magnets have a lower residual magnetic flux density than rare earth magnets. Here, the amount of magnetic flux generated from the permanent magnet depends on the residual magnetic flux density of the permanent magnet. Further, when the amount of magnetic flux generated from the permanent magnet decreases, it is necessary to increase the current (stator current) that flows through the stator winding, and the efficiency of the permanent magnet motor decreases. For this reason, when using a ferrite magnet instead of a rare earth magnet, a ferrite magnet having as high a residual magnetic flux density as possible is used.
On the other hand, a ferrite magnet having a high residual magnetic flux density has a low coercive force, and thus is easily demagnetized. Therefore, when a ferrite magnet having a high residual magnetic flux density is used, it is necessary to increase the thickness of the ferrite magnet (interval between the N pole surface and the S pole surface) in order to increase the holding force.
However, if the thickness of the ferrite magnet is increased without changing the size (diameter) of the rotor core, the magnet surface area (N pole and S pole magnetic pole surface areas) decreases, and the amount of magnetic flux decreases.
For this reason, it has been considered difficult to achieve the same efficiency using a ferrite magnet as when a rare earth magnet is used.
The inventors pay attention to the squareness of the ferrite magnet (ratio [Hk / Hcj] of the magnetic field Hk corresponding to 90% of the residual magnetic flux density Br and the holding force Hcj in the JH demagnetization curve) It was found that the efficiency of a permanent magnet motor using a magnet affects the squareness of the ferrite magnet.
Therefore, an object of the present invention is to provide a technique capable of improving the efficiency of a permanent magnet motor using a ferrite magnet as a permanent magnet.

The present invention can be configured as follows. In the following, the term “parallel” is used to include “an aspect that is substantially parallel”.
One invention relates to a rotor.
The rotor of this invention has the rotor core in which the several magnet insertion hole was formed, and the several permanent magnet inserted in the several magnet insertion hole. The rotor core is typically formed by laminating electromagnetic steel sheets. A plurality of permanent magnets define a d-axis (the direction of the main magnetic flux) and a q-axis (a direction perpendicular to the d-axis). The permanent magnet is magnetized so that the N-pole main pole and the S-pole main pole are alternately arranged along the circumferential direction.
The plurality of magnet insertion holes are seen in a cross section perpendicular to the axial direction, and are arranged in one direction side (for example, clockwise direction side) and the other direction side (for example, counterclockwise direction side) along the circumferential direction with respect to the q axis. ) And is configured by a first magnet insertion hole and a second magnet insertion hole that extend linearly along the q-axis. The first magnet insertion hole is disposed on one side and the other side along the circumferential direction, and extends in parallel to the q axis, and on the outer circumferential side along the radial direction. And an outer peripheral wall and an inner peripheral wall which are arranged on the inner peripheral side and extend along the circumferential direction, and a first side wall and a first oblique wall connected to the inner peripheral wall. The second magnet insertion hole is disposed on one side and the other side along the circumferential direction, and extends in parallel to the q axis, and on the outer circumferential side along the radial direction. And an outer peripheral wall and an inner peripheral wall which are arranged on the inner peripheral side and extend along the circumferential direction, and a second side wall and a second inclined wall connected to the inner peripheral wall.
The plurality of permanent magnets includes a first permanent magnet inserted into the first magnet insertion hole and a second permanent magnet inserted into the second magnet insertion hole.
A first slant wall of the first magnet insertion hole and a second slant wall (d of the second magnet insertion hole disposed on one side along the circumferential direction with respect to the first magnet insertion hole (d The first slant wall of the first magnet insertion hole and the second slant wall of the second magnet insertion hole, which are arranged on both sides of the shaft, are inserted into the first magnet insertion hole. Extending in parallel with the d-axis defined by the permanent magnet and the second permanent magnet inserted into the second magnet insertion hole, and the first inclined wall and the second inclined wall An inner peripheral bridge portion extending linearly along the d-axis is formed. In addition, the second side wall of the first magnet insertion hole and the first side wall (q of the second magnet insertion hole disposed on the other direction side in the circumferential direction with respect to the first magnet insertion hole) An inter-electrode bridge portion is formed by the second side wall of the first magnet insertion hole and the first side wall of the second magnet insertion hole, which are arranged on both sides of the shaft.
The outer peripheral surface of the rotor core is formed by alternately connecting a first curved portion intersecting with the d axis and a second curved portion intersecting with the q axis when viewed in a cross section perpendicular to the axial direction. . The first curved portion is formed in an arc shape having a center of curvature on the d-axis, and the second curved portion has a center of curvature on the q-axis and is larger than the radius of curvature of the first curved portion. It is formed in the circular arc shape which has. Preferably, the center of curvature of the second curved portion is set at a position along the q axis in a direction away from the second curved portion from the rotational center of the rotor core. A portion between the magnet insertion hole and the outer peripheral surface (second curved portion) of the rotor core acts as an outer peripheral bridge portion that prevents a short circuit of the magnetic flux.
In the present invention, as the first permanent magnet and the second permanent magnet, the magnetic field Hk corresponding to 90% of the residual magnetic flux density Br and the holding force Hcj in the JH demagnetization curve (J: magnetization, H: magnetic field). The ratio (Hk / Hcj) to the ferrite magnet satisfying [0.8 ≦ (Hk / Hcj) ≦ 0.85] is used.
The ratio [Hk / Hcj] is also called “squareness”. The JH demagnetization curve is a curve in the second quadrant of the JH curve. The residual magnetic flux density Br is equal to the magnetization (residual magnetization Jr) when the magnetic field (external magnetic field) H in the JH demagnetization curve is zero. The holding force Hcj is equal to the magnetic field when the magnetization J in the JH demagnetization curve is zero.
In the present invention, a first magnet insertion hole and a second magnet insertion hole are provided that extend linearly along the q axis. Thereby, a magnet surface area can be enlarged. An inner peripheral bridge portion is formed between the first magnet insertion hole and the second magnet insertion hole that are adjacent to each other with the d-axis interposed therebetween, and the first magnet insertion hole that is adjacent to the q-axis is Since the inter-electrode bridge portion is formed between the second magnet insertion holes, the strength of the rotor core against centrifugal force can be effectively increased. Thereby, the space | interval between the 1st magnet insertion hole adjacent on both sides of d axis | shaft and a 2nd magnet insertion hole can be made small, and the 1st magnet insertion hole adjacent on both sides of d axis | shaft and 2nd It is possible to prevent the magnetic flux from being short-circuited between the magnet insertion holes. Further, since the first slant wall of the first magnet insertion hole and the second slant wall of the second magnet insertion hole forming the inner peripheral bridge portion extend in parallel to the d-axis (radial direction), the centrifugal The strength of the rotor core against force can be effectively increased. Further, since the outer peripheral surface of the rotor is formed by alternately connecting arc-shaped first curved portions and second curved portions having different radii of curvature, the first magnet insertion hole and the second curved portion are formed. The space | interval of the part between a magnet insertion hole and the outer peripheral surface (2nd curve part) of a rotor core becomes substantially equal along the circumferential direction. As a result, the width (length along the radial direction) of the outer bridge portion can be reduced while suppressing a decrease in the strength of the rotor core against centrifugal force, and the first magnet insertion hole and the second magnet insertion It is possible to prevent the magnetic flux from being short-circuited through a portion between the hole and the outer peripheral surface of the rotor core. Further, as a permanent magnet, the ratio (Hk / Hcj) of the magnetic field Hk and the coercive force Hcj corresponding to 90% of the residual magnetic flux density Br in the JH demagnetization curve is [0.8 ≦ (Hk / Hcj) ≦. 0.85] is used. Thereby, a residual magnetic flux density can be raised, suppressing the fall of holding force. Therefore, the efficiency of the permanent magnet motor can be improved.

In a different form of one invention, the first permanent magnet is disposed on one side and the other side along the circumferential direction, and extends in parallel with the q-axis, and the second side surface; An outer peripheral surface and an inner peripheral surface that are arranged on the outer peripheral side and the inner peripheral side along the radial direction and extend along the circumferential direction, and a first side surface and a first inclined surface connected to the inner peripheral surface The second permanent magnet is formed on the one side and the other side along the circumferential direction, and extends in the radial direction with the first side surface and the second side surface extending parallel to the q axis. The outer peripheral surface and the inner peripheral surface are arranged along the outer peripheral side and the inner peripheral side along the circumferential direction, and are formed by the second side surface and the second inclined surface connected to the inner peripheral surface. Yes.

In another different form of one invention, the corners of the first permanent magnet and the second permanent magnet are linear or arcuate.

Another invention relates to a permanent magnet electric motor including a stator and a rotor supported rotatably with respect to the stator. The stator has a stator core and a stator winding. The rotor has a rotor core formed with a plurality of magnet insertion holes and a plurality of permanent magnets inserted into the plurality of magnet insertion holes. In the present invention, any of the rotors described above is used as the rotor.
The present invention has the same effect as each rotor described above.

  By using the rotor and permanent magnet motor of the present invention, the efficiency of the permanent magnet motor can be improved while using a ferrite magnet as the permanent magnet.

It is a figure which shows schematic structure of the permanent magnet electric motor of 1st Embodiment. It is sectional drawing of the rotor core of the rotor used with the permanent magnet electric motor of 1st Embodiment. FIG. 3 is a partially enlarged view of FIG. 2. It is the elements on larger scale of sectional drawing of the rotor core of the rotor used with the permanent magnet electric motor of 2nd Embodiment. It is the elements on larger scale of sectional drawing of the rotor core of the rotor used with the permanent magnet electric motor of 3rd Embodiment. It is the elements on larger scale of sectional drawing of the rotor core of the rotor used with the permanent magnet electric motor of 4th Embodiment. It is sectional drawing of the rotor core of the rotor used with the permanent magnet electric motor of 5th Embodiment. It is a figure explaining the squareness of a permanent magnet. It is a figure which shows the relationship between the squareness of a permanent magnet, residual magnetic flux density, and coercive force (demagnetizing current). It is sectional drawing of the rotor core of the rotor used with the conventional permanent magnet electric motor.

Embodiments of the present invention will be described below with reference to the drawings.
In the present specification, the “axial direction” indicates the direction of the rotation center line passing through the rotation center O of the rotor in a state where the rotor is rotatably supported with respect to the stator. The “circumferential direction” is a circle centered on the rotation center O when viewed in a cross section perpendicular to the axial direction (direction of the rotation center line) in a state where the rotor is rotatably supported with respect to the stator. The circumferential direction is shown. The “radial direction” indicates a direction passing through the rotation center O when viewed in a cross section perpendicular to the axial direction in a state where the rotor is rotatably supported with respect to the stator.
The “d-axis” is a direction (main magnetic pole) in which the main magnetic flux of the main magnetic pole (N pole, S pole) formed by the permanent magnet inserted in the magnet insertion hole flows when viewed in a cross section perpendicular to the axial direction. The “q-axis” indicates a direction that is electrically perpendicular to the “d-axis” (an electrical angle of 90 degrees).
Further, the description “parallel” is used to include an aspect of “substantially parallel”.
In addition, the descriptions “one direction along the circumferential direction” and “the other direction along the circumferential direction” refer to “clockwise direction (clockwise direction)” and “counterclockwise direction” when viewed in a cross section perpendicular to the axial direction. Direction (counterclockwise direction) ". Of course, conversely, it can also be used to indicate “counterclockwise direction (counterclockwise direction)” and “clockwise direction side (clockwise direction side)”.

A first embodiment of the permanent magnet motor of the present invention is shown in FIGS. FIG. 1 is a diagram illustrating a schematic configuration of the permanent magnet motor 10 according to the first embodiment. 2 is a cross-sectional view of the rotor core 100 used in the permanent magnet motor 10 of the first embodiment as viewed from a direction perpendicular to the axial direction. FIG. 3 is a partially enlarged view of FIG. FIG.
The permanent magnet motor 10 according to the first embodiment includes a stator 20 and a rotor 50 that is rotatably supported with respect to the stator 20.
The stator 20 includes a stator core 30 and a stator winding 40. The stator core 30 is formed by stacking electromagnetic steel plates. The stator core 30 includes a yoke extending along the circumferential direction when viewed in a cross section perpendicular to the axial direction, and a plurality of teeth extending from the yoke along the radial direction toward the rotation center of the rotor 50; It has a slot formed by teeth adjacent in the circumferential direction. The stator winding 40 is inserted into the slot.

The rotor 50 includes a rotor core 100 in which a magnet insertion hole into which a permanent magnet is inserted is formed, and a rotating shaft 60.
The rotor core 100 is formed by laminating electromagnetic steel plates.
A main magnetic pole (N pole, S pole) is formed by a permanent magnet inserted into the magnet insertion hole, and a main magnetic flux is generated by the main magnetic pole.
In the present embodiment, as a permanent magnet to be inserted into the magnet insertion hole, a ferrite magnet having a residual magnetic flux density lower than that of a rare earth magnet but being inexpensive is used.

In the present embodiment, the outer peripheral surface 101 of the rotor core 100 is formed by alternately arranging the first curved portions 101A and the second curved portions 101B when viewed in a cross section perpendicular to the axial direction.
101 A of 1st curve parts are formed in the 1st curve shape which cross | intersects d-axis and protrudes in the outer peripheral direction of the rotor core 100. As shown in FIG. The second curved portion 101B is formed in a second curved shape that intersects the q axis and protrudes in the outer circumferential direction of the rotor core 100. The first curved shape is an arc shape having a radius R1 with the center of curvature at the rotation center O on the d-axis. The second curved line shape is an arc shape having a radius R2 (> R1) having a center of curvature at a point P on the q axis that is away from the rotation center O in the direction opposite to the second curved line portion 101B.

The rotor core 100 is formed with a plurality of magnet insertion holes extending in the circumferential direction along the circumferential direction when viewed in a cross section perpendicular to the axial direction.
In the present embodiment, the magnet insertion hole is disposed on one side (clockwise direction side) along the circumferential direction with respect to the q axis, and is a first magnet insertion that extends linearly along the q axis. And a second magnet insertion hole 112 that is disposed on the other direction side (counterclockwise direction side) along the circumferential direction with respect to the q axis and extends linearly along the q axis. Yes. A magnet insertion hole group is configured by the first magnet insertion hole 111 arranged on one side along the circumferential direction with respect to the q axis and the second magnet insertion hole 112 arranged on the other direction side, A plurality of magnet insertion hole groups are arranged along the circumferential direction.
The first magnet insertion hole 111 is formed by an outer peripheral wall 111a, a first side wall 111b, a second side wall 111c, and an inner peripheral wall 111d. The outer peripheral wall 111a and the inner peripheral wall 111d are arranged on the outer peripheral side (the outer peripheral surface 101 side) and the inner peripheral side (the rotation center O side) along the radial direction (q axis), and extend linearly along the circumferential direction. Yes. The first side wall 111b and the second side wall 111c are arranged on one side (clockwise direction side) and the other direction side (counterclockwise direction side) along the circumferential direction, and are linearly parallel to the q axis. It extends.
Similar to the first magnet insertion hole 111, the second magnet insertion hole 112 is formed by an outer peripheral wall 112a, a first side wall 112b, a second side wall 112c, and an inner peripheral wall 112d.

A first permanent magnet 121 that extends linearly along the q axis is inserted into the first magnet insertion hole 111, and a linear extension extends along the q axis into the second magnet insertion hole 112. The second permanent magnet 122 is inserted.
The first permanent magnet 121 is formed by an outer peripheral surface 121a, a first side surface 121b, a second side surface 121c, and an inner peripheral surface 121d. The outer peripheral surface 121a and the inner peripheral surface 121d are disposed on the outer peripheral side and the inner peripheral side along the radial direction (q-axis), and extend linearly along the circumferential direction. The first side surface 121b and the second side surface 121c are arranged on one side and the other side along the circumferential direction, and extend linearly in parallel to the q axis. The outer peripheral surface 121a, the first side surface 121b, the second side surface 121c, and the inner peripheral surface 121d of the first permanent magnet 121 are the outer peripheral wall 111a, the first side wall 111b, the second peripheral surface 121d of the first magnet insertion hole 111. It arrange | positions in the position which opposes the side wall 111c and the internal peripheral wall 111d.
Similar to the first permanent magnet 121, the second permanent magnet 122 is formed by an outer peripheral surface 122a, a first side surface 122b, a second side surface 122c, and an inner peripheral surface 122d. The outer peripheral surface 122a, the first side surface 122b, the second side surface 122c, and the inner peripheral surface 122d of the second permanent magnet 122 are the outer peripheral wall 112a, the first side wall 112b, and the second inner surface 122d of the second magnet insertion hole 112. It arrange | positions in the position which opposes the side wall 112c and the internal peripheral wall 112d.
A first permanent magnet 121 and a second permanent magnet 122 arranged on both sides of the q axis constitute a permanent magnet group.

The first permanent magnet 121 and the second permanent magnet 122 are magnetized (magnetized) so that adjacent main magnetic poles have different polarities.
In the present embodiment, the first permanent magnet 121 and the second permanent magnet 122 are magnetized along the circumferential direction. For example, as shown in FIG. 3, the first magnet insertion hole 111 and the second magnet insertion hole 112 that constitute the same magnet insertion hole group (arranged on both sides of the q axis). The first permanent magnet 121 and the second permanent magnet 122 inserted into the magnet are magnetized so as to have the same polarity along the circumferential direction. For example, the first side surface 121b of the first permanent magnet 121 and the first side surface 122b of the second permanent magnet 122 constituting the same permanent magnet group become N poles, and the second side of the first permanent magnet 121 The side surface 121c of the second permanent magnet 122 and the second side surface 122c of the second permanent magnet 122 are magnetized so as to have an S pole. That is, one side of the side surfaces of the first permanent magnet 121 and the second permanent magnet 122 constituting the same group of permanent magnets (disposed on both sides of the q axis) along the circumferential direction. The side surfaces 121b and 122b disposed on the side are magnetized so as to have one polarity (S pole or N pole) and the side surfaces 121c and 122c disposed on the other direction side have the other polarity (N pole or S pole). The
Moreover, the 2nd permanent magnet 122 which comprises the permanent magnet group arrange | positioned by the one direction side among the permanent magnet groups adjacent to the circumferential direction and the permanent magnet group which comprises the other direction side are comprised. For one permanent magnet 121, a surface facing along the circumferential direction (the second side surface 122 c of the second permanent magnet 122 disposed on the one direction side along the circumferential direction with respect to the d axis and the other direction side) Are magnetized so that the first side surfaces 121b) of the first permanent magnets 121 arranged at the same polarity have the same polarity. That is, among the permanent magnet groups adjacent in the circumferential direction, the second side surface 122c of the second permanent magnet 122 of the permanent magnet group arranged on one side and the first of the permanent magnet group arranged on the other side. The permanent magnet 121 is magnetized so that the first side surface 121b has the same polarity.
As a method of magnetizing the permanent magnet, a parallel magnetization method of magnetizing in parallel or a radial magnetization method of magnetizing in the radial direction from the center point can be used.

In the present embodiment, a first outer bridge portion 105a is formed between the outer peripheral wall 111a of the first magnet insertion hole 111 and the outer peripheral surface 101 (second curved portion 101B) of the rotor core 100, and the second A second outer peripheral bridge portion 105 b is formed between the outer peripheral wall 112 a of the magnet insertion hole 112 and the outer peripheral surface 101 (second curved portion 101 B) of the rotor core 100.
By the first outer peripheral bridge portion 105a and the second outer peripheral bridge portion 105b, the first magnet insertion hole 111, the second magnet insertion hole 112, and the outer peripheral surface 101 of the rotor core 100 (second curved portion 101B). It is possible to suppress a short circuit of the magnetic flux through the portion between the two.
The first outer peripheral bridge portion 105a and the second outer peripheral bridge portion 105b correspond to the “third bridge portion” of the present invention.

An inner peripheral bridge portion 106 is formed between the magnet insertion hole groups adjacent in the circumferential direction. That is, the second side wall 112c of the second magnet insertion hole 112 constituting the magnet insertion hole group arranged on one side among the magnet insertion hole groups adjacent in the circumferential direction, and the magnet arranged on the other direction side Between the first side walls 111b of the first magnet insertion holes 111 constituting the insertion hole group (the second side wall 112c of the second magnet insertion hole 112 arranged on one side with respect to the d axis and the other direction) An inner peripheral bridge portion 106 is formed between the first side walls 111b of the first magnet insertion hole 111 disposed on the side.
By this inner peripheral bridge portion 106, between the magnet insertion hole groups adjacent in the circumferential direction (the second magnet insertion hole arranged on one side with respect to the d axis and the first magnet arranged on the other direction side) It is possible to prevent the magnetic flux from being short-circuited through the portion between the insertion holes).
Preferably, the minimum value of the width (length along the circumferential direction) T of the inner peripheral bridge portion 106 is set in a range of 0.35 mm to 0.5 mm.
The inner bridge 106 corresponds to the “first bridge” of the present invention.

Further, an inter-electrode bridge portion 107 is formed between the first magnet insertion hole 111 and the second magnet insertion hole 112 constituting the same magnet insertion hole group. That is, between the second side wall 111c of the first magnet insertion hole 111 and the first side wall 112b of the second magnet insertion hole 112 constituting the same magnet insertion hole group (arranged on one side with respect to the q axis). Between the second side wall 111c of the first magnet insertion hole 111 and the first side wall 112b) of the second magnet insertion hole 112 disposed on the other direction side). ing.
Since the inter-electrode bridge portion 107 extends linearly along the radial direction (q-axis), the strength against centrifugal force increases.
It is possible to prevent the magnetic flux from being short-circuited through the portion between the first magnet insertion hole 111 and the second magnet insertion hole 112 constituting the same magnet insertion hole group by the inter-electrode bridge portion 107.
Preferably, the width (length along the circumferential direction) E of the inter-electrode bridge portion 107 is set within a range of 0.35 mm to 0.5 mm.
The inter-electrode bridge portion 107 corresponds to the “second bridge portion” of the present invention.

  In the present embodiment, since the permanent magnets (first permanent magnet 112 and second permanent magnet 122) are arranged so as to extend along the radial direction (q-axis), the magnet surface area of the permanent magnet is increased. be able to. Thereby, the amount of magnetic flux generated from the permanent magnet can be increased.

In the conventional rotor core 600, as indicated by a broken line arrow in FIG. 10, the magnetic flux is short-circuited through a portion between the magnet housing hole 611 and the inner peripheral surface 602 of the rotor core 600. As a method for suppressing the short circuit of the magnetic flux, it is conceivable to reduce the interval between the magnet insertion holes 611 adjacent in the circumferential direction, particularly the interval W on the inner peripheral surface 602 side. On the other hand, when the interval W is reduced, the strength of the rotor core 600 against centrifugal force is reduced. For this reason, there is a limit in reducing the interval W, and the short circuit of the magnetic flux cannot be sufficiently suppressed.
In the present embodiment, between the magnet insertion hole groups adjacent in the circumferential direction (the second magnet insertion hole 112 arranged on one side along the circumferential direction with respect to the d axis and the other direction side. An inner peripheral bridge portion 106 is formed between the first magnet insertion holes 111). Moreover, between the 1st magnet insertion hole 111 and the 2nd magnet insertion hole 112 which comprise the same magnet insertion hole group (the 1st magnet insertion hole 111 arrange | positioned at one direction side with respect to q axis | shaft, and the other direction) An inter-electrode bridge portion 107 is formed between the second magnet insertion holes 112 disposed on the side. The inner bridge portion 106 and the inter-electrode bridge portion 107 can increase the strength of the rotor core 100 against centrifugal force. In particular, the second side wall 111c of the first magnet insertion hole 111 and the first side wall 112b of the second magnet insertion hole 112 forming the inter-electrode bridge portion 107 are linearly parallel to the q axis (radial direction). Since it extends, the intensity | strength with respect to a centrifugal force can be raised more. In this case, since the space | interval of the inner periphery bridge | bridging part 106 can be made small, between the adjacent magnet insertion hole groups (The 1st magnet insertion hole 111 and 2nd magnet insertion hole which are arrange | positioned on both sides on both sides of d axis | shaft) 112), the magnetic flux can be further prevented from being short-circuited.

  Therefore, even when a ferrite magnet, which has a lower magnetic flux density than a rare earth magnet but is inexpensive, is used as a permanent magnet, the magnet surface area can be increased while suppressing a decrease in strength against centrifugal force and a short circuit of the magnetic flux. A sufficient amount of magnetic flux can be secured.

In the present embodiment, the connecting portion (switching portion) 101a between the first curved portion 101A and the second curved portion 101B that forms the outer peripheral surface 101 of the rotor core 100 is located where the stator teeth are opposed to each other. A rapid change in the amount of magnetic flux flowing through the teeth when passing can be suppressed. As a result, it is possible to prevent an increase in harmonic components contained in the waveform of the induced voltage induced in the stator winding due to a sudden change in the amount of magnetic flux flowing through the teeth. Based on this, the inverter can be accurately controlled.
Moreover, the space | interval between the outer peripheral wall 111a of the 1st magnet insertion hole 111 and the 2nd curve part 101B of the outer peripheral surface 101 of the rotor core 100 becomes substantially equal along the circumferential direction. Thereby, the space | interval between the outer peripheral wall 111a and the 2nd curve part 101B can be made small, and the outer peripheral wall 111a of the 1st magnet insertion hole 111 and the outer peripheral surface 101 (2nd curve part) of the rotor core 100 are obtained. 101B) can prevent the magnetic flux from being short-circuited through the portion between the two.

Next, the squareness of the permanent magnet will be described.
As a magnetization curve representing the magnetic characteristics of the permanent magnet, a JH curve representing a change in the magnetization J of the permanent magnet with respect to the magnetic field (external magnetic field) H as shown in FIG. 8 is used. In FIG. 8, the horizontal axis represents the magnetic field (external magnetic field) H (Oe), and the vertical axis represents the magnetization J (G).
Of the JH curve shown in FIG. 8, the portion in the second quadrant is called a JH demagnetization curve, and is used to represent the performance of the magnet. In the JH demagnetization curve, the magnetic field H is gradually reduced with the permanent magnets magnetized, and the magnetization J when the magnetic field H becomes 0 is called residual magnetization Jr. This residual magnetization Jr is equal to the residual magnetic flux density Br of the permanent magnet. When the magnetic field H is further applied in the opposite (minus) direction and the magnetization J becomes 0, the magnetic field H is called a holding force Hcj. The holding force Hcj can also be expressed as a demagnetizing current for applying the magnetic field H in the reverse direction so that the magnetization J becomes zero.
Here, in the JH demagnetization curve shown in FIG. 8, the magnetic field H corresponding to 90% (= 0.9Br) of the residual persistent density Br (= residual magnetization Jr) is defined as Hk. The ratio (Hk / Hcj) between the magnetic field Hk and the holding force Hcj is called the squareness of the permanent magnet.

FIG. 9 shows the results of measuring the relationship between the squareness (Hk / Hcj), the residual magnetic flux density Br, and the coercive force Hcj (or demagnetizing current) for the ferrite magnet. In FIG. 9, the horizontal axis indicates squareness (Hk / Hcj) (%), one vertical axis indicates the residual magnetic flux density Br (G), and the other vertical axis indicates the holding force Hcj (Oe) or the demagnetizing current. (A) is shown. The solid line indicates the residual magnetic flux density Br, and the broken line indicates the holding force Hcj or the demagnetizing current.
From FIG. 9, it can be seen that the residual magnetic flux density Br maintains a high state when the squareness is 85% or less, but decreases when it exceeds 85%. As described above, when the residual magnetic flux density Br is high, the amount of magnetic flux increases.
Further, it can be seen that the holding force Hcj or the demagnetizing current is kept high when the squareness is 80% or more, but becomes low when the squareness becomes smaller than 80%. As described above, when the holding force Hcj or the demagnetizing current is low, demagnetization is likely to occur. Therefore, it is necessary to increase the thickness of the ferrite magnet. In this case, it is difficult to increase the amount of magnetic flux.
From the above points, while using a ferrite magnet having squareness (Hk / Hcj) that satisfies [0.8 ≦ squareness (Hk / Hcj) ≦ 0.85], it is possible to suppress a decrease in holding force Hcj. It can be seen that the residual magnetic flux density Br can be increased.
Therefore, in the present embodiment, as the first permanent magnet 121 and the second permanent magnet 122, the squareness (Hk / Hcj) satisfying [0.8 ≦ squareness (Hk / Hcj) ≦ 0.85]. The ferrite magnet which has is used.

Next, another embodiment of the present invention will be described.
In each of the following embodiments, since the configuration of the stator is the same as that of the first embodiment, only the configuration of the rotor will be described.
Moreover, the component to which the reference numeral attached | subjected to each component of 1st Embodiment is attached | subjected with the same reference numeral except the 3rd digit represents the same thing.
Further, as the permanent magnet, the same ferrite magnet as that in the first embodiment is used.

A rotor core 200 of the rotor used in the permanent magnet motor according to the second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a partially enlarged view of a cross-sectional view of the rotor core 200 viewed from a direction perpendicular to the axial direction.
As in the first embodiment, the outer peripheral surface 201 of the rotor core 200 is a second curve that intersects the first curve portion 201A that intersects the d-axis and the q-axis when viewed in a cross section perpendicular to the axial direction. The curved portions 201B are alternately connected.
As in the first embodiment, the rotor core 200 is disposed on one side and the other side along the circumferential direction with respect to the q axis, as viewed in a cross section perpendicular to the axial direction, and the q axis A first magnet insertion hole 211 and a second magnet insertion hole 212 extending in a straight line are formed. A first magnet insertion hole 211 and a second magnet insertion hole 222 arranged on both sides of the q axis constitute a magnet insertion hole group.
In the first magnet insertion hole 211 and the second magnet insertion hole 212, as in the first embodiment, the first permanent magnet 221 and the second permanent are extended linearly along the q axis. A magnet 222 is inserted.
The first permanent magnet 221 and the second permanent magnet 222 are magnetized along the circumferential direction, as in the first embodiment.

In the present embodiment, the shapes of the first permanent magnet 221 and the second permanent magnet 222 are different from those of the first embodiment.
In the present embodiment, the corners of the permanent magnet are formed in an R shape (arc shape). That is, when viewed in a cross section perpendicular to the axial direction, an R surface (arc-shaped surface) 221e is formed at the corner of the first permanent magnet 221 and an R surface 222e is formed at the corner of the second permanent magnet 222. Has been. The corners forming the R plane can be selected as appropriate.

A rotor core 300 of the rotor used in the permanent magnet motor according to the third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a partially enlarged view of a cross-sectional view of the rotor core 300 viewed from a direction perpendicular to the axial direction.
As in the first embodiment, the outer peripheral surface 301 of the rotor core 300 is formed by alternately connecting the first curved portion 301A that intersects the d axis and the second curved portion 301B that intersects the q axis. Is formed.
As in the first embodiment, the rotor core 300 is disposed on one side and the other side along the circumferential direction with respect to the q axis, as viewed in a cross section perpendicular to the axial direction, and the q axis A first magnet insertion hole 311 and a second magnet insertion hole 312 that extend linearly along are formed. A first magnet insertion hole 311 and a second magnet insertion hole 312 arranged on both sides of the q axis constitute a magnet insertion hole group.
In the first magnet insertion hole 311 and the second magnet insertion hole 312, as in the first embodiment, the first permanent magnet 321 and the second permanent are extended linearly along the q axis. A magnet 322 is inserted.
Similar to the first embodiment, the first permanent magnet 321 and the second permanent magnet 322 are magnetized along the circumferential direction.

In the present embodiment, the shapes of the first permanent magnet 321 and the second permanent magnet 322 are different from those of the first embodiment.
In the present embodiment, the corners of the permanent magnet are tapered (straight). That is, tapered surfaces (linear surfaces) 321 f are formed at the corners of the first permanent magnet 321, and tapered surfaces 322 f are formed at the corners of the second permanent magnet 322. The corners forming the tapered surface can be selected as appropriate.

A rotor core 400 of the rotor used in the permanent magnet motor according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a partially enlarged view of a cross-sectional view of the rotor core 400 viewed from a direction perpendicular to the axial direction.
As in the first embodiment, the outer peripheral surface 401 of the rotor core 400 is formed by alternately connecting a first curved portion 401A that intersects the d axis and a second curved portion 401B that intersects the q axis. Is formed.

The rotor core 400 is disposed in one direction side and the other direction side along the circumferential direction with respect to the q axis when viewed in a cross section perpendicular to the axial direction, and extends linearly along the q axis. One magnet insertion hole 411 and a second magnet insertion hole 412 are formed. A first magnet insertion hole 411 and a second magnet insertion hole 412 arranged on both sides of the q axis constitute a magnet insertion hole group.
The first magnet insertion hole 411 is formed by an outer peripheral wall 411a, a first side wall 411b, a second side wall 411c, an inner peripheral wall 411d, and a first inclined wall 411g. The outer peripheral wall 411a and the inner peripheral wall 411d are arranged on the outer peripheral side and the inner peripheral side along the radial direction (q-axis), and extend linearly along the circumferential direction. The first side wall 411b and the second side wall 411c are arranged on one side and the other side along the circumferential direction, and extend linearly in parallel to the q axis. The first inclined wall 411g is connected to the first side wall 411b and the inner peripheral wall 411d and extends linearly.
The second magnet insertion hole 412 is formed by an outer peripheral wall 412a, a first side wall 412b, a second side wall 412c, an inner peripheral wall 412d, and a second inclined wall 412h. The outer peripheral wall 412a and the inner peripheral wall 412d are disposed on the outer peripheral side and the inner peripheral side along the radial direction (q-axis), and extend linearly along the circumferential direction. The first side wall 412b and the second side wall 412c are arranged on one side and the other side along the circumferential direction, and extend linearly in parallel to the q axis. The second inclined wall 412h is connected to the second side wall 412c and the inner peripheral wall 412d, and extends linearly.
The second slant wall 412h of the second magnet insertion hole 412 constituting the magnet insertion hole group arranged on one direction side among the permanent magnet groups adjacent along the circumferential direction and the magnet insertion arranged on the other direction side. The first slant wall 411g of the first magnet insertion hole 411 constituting the hole group (the second slant wall 412h of the second magnet insertion hole 412 disposed on the one direction side with respect to the d axis and the other direction side) The first slant wall 411g) of the first magnet insertion hole 411 disposed in the second magnet insertion hole 412 and the first permanent magnet 422 inserted into the first magnet insertion hole 411 and the first It extends linearly in parallel with the d axis defined by the permanent magnet 421.

The first permanent magnet 421 inserted into the first magnet insertion hole 411 is formed by an outer peripheral surface 421a, a first side surface 421b, a second side surface 421c, an inner peripheral surface 421d, and a first inclined surface 421g. . The outer peripheral surface 421a and the inner peripheral surface 421c are arranged on the outer peripheral side and the inner peripheral side along the radial direction, and extend linearly along the circumferential direction. The first side surface 421b and the second side surface 421c are arranged on one side and the other side along the circumferential direction, and extend linearly in parallel to the q axis. The first inclined surface 421g is connected to the first side surface 421b and the inner peripheral surface 421d, and extends linearly.
The second permanent magnet 422 is formed by an outer peripheral surface 422a, a first side surface 422b, a second side surface 422c, an inner peripheral surface 422d, and a second inclined surface 422h. The outer peripheral surface 422a and the inner peripheral surface 422d are arranged on the outer peripheral side and the inner peripheral side along the radial direction, and extend linearly along the circumferential direction. The first side surface 422b and the second side surface 422c are arranged on one side and the other side along the circumferential direction, and extend linearly in parallel to the q axis. The second inclined surface 422h is connected to the second side surface 422c and the inner peripheral surface 422d, and extends linearly.
The first permanent magnet 421 and the second permanent magnet 422 are magnetized along the circumferential direction as in the first embodiment.

In the present embodiment, a first outer bridge portion 405a is formed between the first magnet insertion hole 411 (outer peripheral wall 411a) and the outer peripheral surface 401 (second curved portion 401B) of the rotor core 400. A second outer peripheral bridge portion 405b is formed between the second magnet insertion hole 412 (outer peripheral wall 412a) and the outer peripheral surface 401 (second curved portion 401B) of the rotor core 400.
Further, the inner peripheral bridge portion 406 is located between the magnet insertion hole groups adjacent in the circumferential direction (between the first magnet insertion hole 411 and the second magnet insertion hole 412 arranged on both sides of the d axis). Is formed.
Also, between the first magnet insertion hole 411 and the second magnet insertion hole 412 constituting the same magnet insertion hole group (the first magnet insertion hole 411 and the second magnet arranged on both sides across the q axis) An inter-electrode bridge portion 407 is formed between the insertion holes 412).
In particular, in the present embodiment, the inner peripheral bridge portion 406 has a second magnet insertion hole 412 constituting a magnet insertion hole group arranged on one side of the magnet insertion hole groups adjacent in the circumferential direction. Between the two slant walls 412h and the first slant wall 411g of the first magnet insertion hole 411 constituting the magnet insertion hole group disposed on the other direction side (first disposed on both sides of the d-axis). The first slant wall 411g of the second magnet insertion hole 411 and the second slant wall 412h of the second magnet insertion hole 412) are formed.
Preferably, the inner bridge portion 406 has a width (length along the circumferential direction) T set in a range of 0.35 mm to 0.5 mm, and a length (length along the radial direction) L. It is set to 1.5 mm or more.

In the present embodiment, the second inclined wall 412h of the second magnet insertion hole 412 constituting the magnet insertion hole group arranged on one side among the magnet insertion hole groups adjacent in the circumferential direction, and the other direction side The first slant wall 411g of the first magnet insertion hole 411 constituting the magnet insertion hole group disposed on the first slant wall 411g and the second slant wall 412h disposed on both sides across the d axis. Since the inner circumferential bridge portion 406 is formed by this, it is possible to prevent the magnetic flux from being short-circuited through the portion between the magnet insertion hole groups adjacent in the circumferential direction. Further, the first slant wall 411g of the first magnet insertion hole 411 and the second slant wall 412h of the second magnet insertion hole 412 forming the inner peripheral bridge portion 406 extend linearly in parallel with the d axis. Therefore, the strength of the rotor core 400 against centrifugal force can be further increased. Therefore, the width T of the inner peripheral bridge portion 406 can be further reduced, and the magnetic flux can be further prevented from being short-circuited through the portion between the magnet insertion hole groups adjacent in the circumferential direction.
Note that the cross-sectional shape of the first permanent magnet 421 may not include the first inclined surface 411g. For example, a quadrangular cross-sectional shape formed by the outer peripheral surface 421a, the first side surface 421b, the second side surface 421c, and the inner peripheral surface 421d may be used. The cross-sectional shape of the second permanent magnet 422 may not include the second inclined surface 422h. For example, a quadrangular cross-sectional shape formed by the outer peripheral surface 422a, the first side surface 422b, the second side surface 422c, and the inner peripheral surface 422d may be used.

In the first to fourth embodiments, the outer peripheral surface of the rotor core is formed by the first curved portion and the second curved portion having different radii of curvature, but it may be formed in a circular shape.
A rotor core 500 of a rotor used in a permanent magnet motor according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view of the rotor core 500 viewed from a direction perpendicular to the axial direction. In the present embodiment, the outer peripheral surface of the rotor core 100 of the first embodiment is formed in an arc shape.
The outer peripheral surface 501 of the rotor core 500 has a circular shape when viewed in a cross section perpendicular to the axial direction.
As in the first embodiment, the rotor core 500 is disposed on one side and the other side along the circumferential direction with respect to the q axis, as viewed in a cross section perpendicular to the axial direction, and the q axis A first magnet insertion hole 511 and a second magnet insertion hole 512 that extend linearly along are formed. A first magnet insertion hole 511 and a second magnet insertion hole 512 arranged on both sides of the q axis constitute a magnet insertion hole group.
Similar to the first embodiment, the first magnet insertion hole 511 and the second magnet insertion hole 512 have a first permanent magnet 521 and a second permanent permanent extending linearly along the q axis. A magnet 522 is inserted.
The first permanent magnet 521 and the second permanent magnet 522 are magnetized along the circumferential direction, as in the first embodiment.

The present invention is not limited to the configuration described in the embodiment, and various changes, additions, and deletions are possible.
Each structure described in the embodiment can be used alone, or can be appropriately selected and used in combination.
The rotor core preferably has an outer peripheral surface formed by a first curved portion and a second curved portion having different radii of curvature when viewed in a cross section perpendicular to the axial direction, but has a circular outer peripheral surface. It may be.
The shape of the magnet insertion hole and the permanent magnet is not limited to the shape described in the embodiment, and can be set to various shapes.
In a state where the permanent magnet is inserted in the magnet insertion hole, a configuration having a gap on the outer peripheral surface side from the permanent magnet, a configuration having a gap on the inner peripheral surface side from the permanent magnet, or an outer peripheral side and an inner periphery from the permanent magnet The structure which has a space | gap on the side, ie, the structure which has a space | gap on at least one of an outer peripheral side and an inner peripheral side from a permanent magnet can also be used. By providing a gap on the inner peripheral surface side, it is possible to suppress the magnetic flux from being short-circuited via the portion on the inner peripheral side from the magnet insertion hole. In addition, by providing a gap on the outer peripheral side, it is possible to suppress the magnetic flux from being short-circuited through a portion on the outer peripheral side from the magnet insertion hole.
By using a ferrite magnet having a squareness (Hk / Hcj) satisfying [0.8 ≦ (Hk / Hcj) ≦ 0.85], the residual magnetic flux density is increased and the amount of magnetic flux is reduced while suppressing the decrease in holding force. It is preferable to use a combination of a configuration for increasing and a configuration for increasing the amount of magnetic flux by increasing the surface area of the magnet, but only one of the configurations can be used.
For example, “having a rotor core formed with a plurality of magnet insertion holes and a plurality of permanent magnets inserted into the plurality of magnet insertion holes, the d-axis and the q-axis are defined by the plurality of permanent magnets. The rotor is a rotor, and the plurality of magnet insertion holes are arranged on one side and the other side along the circumferential direction with respect to the q axis when viewed in a cross section perpendicular to the axial direction, and along the q axis. It is comprised by the 1st magnet insertion hole and 2nd magnet insertion hole which are extended in a straight line, and these permanent magnets are the 1st permanent magnet inserted in the 1st magnet insertion hole, and the above-mentioned It is comprised by the 2nd permanent magnet inserted in a 2nd magnet insertion hole, The said 1st magnet insertion hole and the said 2nd magnet insertion hole are the said one direction side and said other along a circumferential direction Having a first side wall and a second side wall arranged on the direction side; An inner bridge formed by the first side wall of the first magnet insertion hole and the second side wall of the second magnet insertion hole disposed on the one direction side with respect to the first magnet insertion hole. And the first side of the second magnet insertion hole arranged on the other direction side with respect to the first magnet insertion hole. A rotor characterized in that an inter-electrode bridge portion is formed by a side wall. ”

The present invention can also be configured as follows.
(Aspect 1)
“A rotor having a rotor core in which a plurality of magnet insertion holes are formed and a plurality of permanent magnets inserted in the plurality of magnet insertion holes, the d axis and the q axis being defined by the plurality of permanent magnets The plurality of magnet insertion holes are arranged on one side and the other side along the circumferential direction with respect to the q axis when viewed in a cross section perpendicular to the axial direction, and are linear along the q axis. The first magnet insertion hole and the second magnet insertion hole extending to the first magnet insertion hole, the plurality of permanent magnets being inserted into the first magnet insertion hole and the second magnet. The first permanent magnet insertion hole and the second permanent magnet insertion hole are arranged in the one direction side and the other direction side along a circumferential direction. Having a first side wall and a second side wall arranged on the first side, An inner peripheral bridge portion is formed by the first side wall of the magnet insertion hole and the second side wall of the second magnet insertion hole arranged on the one direction side with respect to the first magnet insertion hole. The gap between the second side wall of the first magnet insertion hole and the first side wall of the second magnet insertion hole disposed on the other direction side with respect to the first magnet insertion hole. A bridge portion is formed, and a ferrite magnet is used as the first permanent magnet and the second permanent magnet, and the ferrite magnet is 90% of the residual magnetic flux density Br in the JH demagnetization curve. The ratio (Hk / Hcj) of the magnetic field Hk and the holding force Hcj corresponding to the above is [0.8 ≦ (Hk / Hcj) ≦ 0.85]. ”
(Aspect 2)
“The rotor according to aspect 1, wherein the first magnet insertion hole is disposed on the one direction side and the other direction side along the circumferential direction, and extends in parallel with the q axis. And the second side wall, disposed on the outer peripheral side and the inner peripheral side along the radial direction and extending along the circumferential direction, and connected to the first side wall and the inner peripheral wall. The first slant wall is formed, and the second magnet insertion hole is disposed on the one direction side and the other direction side along the circumferential direction, and extends in parallel with the q axis. A side wall and the second side wall are arranged on the outer peripheral side and the inner peripheral side along the radial direction, and are connected to the outer peripheral wall and the inner peripheral wall extending along the circumferential direction, and connected to the second side wall and the inner peripheral wall. Formed by the second inclined wall, and the first magnet insertion hole has the first The wall and the second oblique wall of the second magnet insertion hole arranged on the one direction side along the circumferential direction with respect to the first magnet insertion hole are formed in the first magnet insertion hole. It extends in parallel with the d axis defined by the first permanent magnet to be inserted and the second permanent magnet to be inserted into the second magnet insertion hole, and forms the inner peripheral bridge portion. Rotor characterized by. "
(Aspect 3)
“The rotor according to aspect 1 or 2, wherein the outer peripheral surface of the rotor core is a first curved portion intersecting with the d axis and a second intersecting with the q axis when viewed in a cross section perpendicular to the axial direction. The first curved portion is formed in an arc shape having a center of curvature on the d-axis, and the second curved portion is a center of curvature on the q-axis. And a rotor having a radius of curvature larger than that of the first curved portion.
(Aspect 4)
“A stator and a rotor supported to be rotatable with respect to the stator, the stator having a stator core and a stator winding, and the rotor having a plurality of magnet insertion holes. And a permanent magnet motor having a plurality of permanent magnets inserted into the plurality of magnet insertion holes, wherein the rotor according to any one of aspects 1 to 3 is used as the rotor. Permanent magnet motor characterized by being used. "

DESCRIPTION OF SYMBOLS 10 Permanent magnet motor 20 Stator 30 Stator core 40 Stator winding 50 Rotor 60 Rotating shaft 100, 200, 300, 400, 500, 600 Rotor core 101, 201, 301, 401, 501, 601 Outer peripheral surface 101A , 201A, 301A, 401A First curve portions 101B, 201B, 301B, 401B Second curve portions 101a, 201a, 301a. 401a Connection point 102, 202, 302, 402, 502, 602 Inner peripheral surface 105a, 105b, 205a, 205b, 305a, 305b, 405a, 405b, 505a, 505b Outer peripheral bridge part 106, 206, 306, 406, 506, 606 Inner bridge portions 107, 207, 307, 407, 507 Inter-electrode bridge portions 111, 112, 211, 212, 311, 312, 411, 412, 511, 512, 611 Magnet insertion holes 111a, 112a, 211a, 212a, 311a 312a, 411a, 412a
Peripheral walls 111b, 111c, 112b, 112c, 211b, 211c, 212b, 212c, 311b, 311c, 312b, 312c, 411b, 411c, 412b, 412c
Side walls 111d, 112d, 211d, 212d, 311d, 312d, 411d, 412d
Inner peripheral walls 121, 122, 221, 222, 321, 322, 421, 422, 521, 522, 621 Permanent magnets 121a, 122a, 221a, 222a, 321a, 322a, 421a, 422a
Outer peripheral surfaces 121b, 121c, 122b, 122c, 221b, 221c, 222b, 222c, 321b, 321c, 322b, 322c, 421b, 421c, 422b, 422c
Side surface 121d, 122d, 221d, 222d, 321d, 322d, 421d, 422d
Inner peripheral surfaces 221e, 222e R surfaces 321f, 322f Tapered surfaces 411g, 412h Slope walls 421g, 422h Slope

Claims (4)

A rotor having a rotor core formed with a plurality of magnet insertion holes and a plurality of permanent magnets inserted into the plurality of magnet insertion holes, wherein a d-axis and a q-axis are defined by the plurality of permanent magnets. There,
The plurality of magnet insertion holes are disposed on one side and the other side along the circumferential direction with respect to the q axis when viewed in a cross section perpendicular to the axial direction, and extend linearly along the q axis. It is composed of a first magnet insertion hole and a second magnet insertion hole,
The plurality of permanent magnets are composed of a first permanent magnet inserted into the first magnet insertion hole and a second permanent magnet inserted into the second magnet insertion hole,
The first magnet insertion hole is disposed on the one direction side and the other direction side along the circumferential direction, and extends in a radial direction with a first side wall and a second side wall extending parallel to the q axis. The outer peripheral wall and the inner peripheral wall are arranged on the outer peripheral side and the inner peripheral side, and extend along the circumferential direction, and are formed by the first side wall and the first oblique wall connected to the inner peripheral wall. And
The second magnet insertion hole is disposed on the one direction side and the other direction side along the circumferential direction, and extends in a radial direction with a first side wall and a second side wall extending parallel to the q axis. The outer peripheral wall and the inner peripheral wall are arranged on the outer peripheral side and the inner peripheral side and extend along the circumferential direction, and are formed by the second side wall and the second inclined wall connected to the inner peripheral wall. And
The first inclined wall of the first magnet insertion hole and the second of the second magnet insertion hole disposed on the one direction side along the circumferential direction with respect to the first magnet insertion hole. The slant wall extends in parallel with the d-axis defined by the first permanent magnet inserted into the first magnet insertion hole and the second permanent magnet inserted into the second magnet insertion hole. In addition, an inner peripheral bridge portion extending linearly along the d-axis is formed by the first and second inclined walls,
The second side wall of the first magnet insertion hole and the first side of the second magnet insertion hole disposed on the other direction side along the circumferential direction with respect to the first magnet insertion hole. The inter-electrode bridge is formed by the side wall,
The outer peripheral surface of the rotor core is formed by alternately connecting a first curved portion intersecting the d axis and a second curved portion intersecting the q axis when viewed in a cross section perpendicular to the axial direction. The first curved portion is formed in an arc shape having a center of curvature on the d-axis, the second curved portion has a center of curvature on the q-axis, and the curvature of the first curved portion is It is formed in an arc shape having a radius of curvature greater than the radius,
Ferrite magnets are used as the first permanent magnet and the second permanent magnet ,
The ferrite magnet has a ratio (Hk / Hcj) of the magnetic field Hk and the coercive force Hcj corresponding to 90% of the residual magnetic flux density Br in the JH demagnetization curve [0.8 ≦ (Hk / Hcj) ≦ 0. . 85]. The rotor according to claim 1,
The first permanent magnet is disposed on the one direction side and the other direction side along the circumferential direction, and extends along the radial direction with a first side surface and a second side surface extending parallel to the q axis. An outer peripheral surface and an inner peripheral surface which are arranged on the outer peripheral side and the inner peripheral side and extend along the circumferential direction, and are formed by the first side surface and the first inclined surface connected to the inner peripheral surface. And
The second permanent magnets are arranged on the one direction side and the other direction side along the circumferential direction, and extend along the radial direction with a first side surface and a second side surface extending parallel to the q axis. An outer peripheral surface and an inner peripheral surface which are disposed on the outer peripheral side and the inner peripheral side and extend along the circumferential direction, and are formed by the second side surface and the second inclined surface connected to the inner peripheral surface. A rotor characterized by having The rotor according to claim 2, wherein
A corner of each of the first permanent magnet and the second permanent magnet is formed in a linear shape or an arc shape. A stator and a rotor supported rotatably with respect to the stator, the stator having a stator core and a stator winding, the rotor having a plurality of magnet insertion holes; 4. A permanent magnet motor having a formed rotor core and a plurality of permanent magnets inserted into the plurality of magnet insertion holes, wherein the rotor is according to claim 1. A permanent magnet electric motor characterized by using a rotor.

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