JP2017070039A - Rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor which can reduce a torque ripple as compared with conventional ones while suppressing reduction in amount of linkage flux of a magnet as much as possible.SOLUTION: A rotor 10 comprises: a rotor core 12 that includes a plurality of magnet holes 14, is formed by laminating a plurality of core sheets made of a magnetic steel sheet, and has a cylindrical shape; and a bond magnet 16 that is filled to each of the magnet holes 14. An end part 16B close to a peripheral surface of the rotor core 12 positioned on a q-axial side of each of the bond magnets 16 is magnetized to a direction obliquely crossing to a tangent line TL at an intersection point I of the q axis with the peripheral surface. With no or little deterioration of the amount of linkage flux of the bond magnet 16 in a magnetic pole MP, a steep change in gap magnetic flux density between adjacent magnetic poles MP is moderated, and a torque ripple is reduced.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rotor used in a radial gap type rotating electrical machine, and more particularly to a rotor for an embedded magnet type rotating electrical machine.

  A radial gap type rotating electrical machine is a rotating electrical machine including a rotor disposed to be rotatable about a rotation axis and a stator disposed with a gap in the radial direction of the rotor. There exists what is called an interior permanent magnet (Interior Permanent Magnet) type | mold (henceforth "IPM type | mold") in this kind of rotary electric machine.

  As shown in FIG. 6A, a general rotor 100 for an IPM type rotating electrical machine includes a cylindrical rotor core 102 in which a plurality of core sheets (not shown) made of electromagnetic steel plates are laminated. Yes. In the rotor core 102, a plurality of (four in this example) magnet holes 104 penetrating in the axial direction are provided at equal pitches in the circumferential direction. A magnet 106 is embedded in each of the magnet holes 104. In this example, a bonded magnet that is magnetized and cured by filling a corresponding magnet hole 104 with a magnet material containing magnetic powder and a resin binder by injection molding is employed as the magnet 106.

  Each of the magnets 106 has a main body portion 106A having a flat plate shape, and an end portion 106B bent from the side end of the main body portion 106A toward the outer peripheral surface of the rotor core 102. The magnetic pole surfaces 106N, 106S on the outer peripheral surface side of the main body portion 106A are magnetized so as to have different polarities (N pole, S pole) between the magnets 106 adjacent in the circumferential direction. A four-pole magnetic pole MP in which N poles and S poles are alternately arranged in the circumferential direction is formed on the outer peripheral portion of the rotor core 102 magnetized by each of the magnets 106 and facing the magnetic pole faces 106N and 106S. Yes. In the rotor 100, the line connecting the center of each magnetic pole MP and the axis of the rotor core 102 is the d-axis, and the line connecting the midpoint between the centers of the adjacent magnetic poles MP and the axis is the q-axis.

  In the rotor 100 having the above-described configuration, as shown in FIG. 6B, among the magnetic fields formed by each of the magnets 106, the magnetic fields in the respective end portions 106 </ b> B are generally oriented in the circumferential direction of the rotor core 102. Is magnetized. As a result, the magnetic flux leakage from the magnet 106 is reduced, and a decrease in the amount of interlinkage magnetic flux of the magnet 106 can be suppressed as much as possible (for example, paragraphs [0006] and [0027] of Patent Document 1; FIG. etc).

  However, when each end portion 106B of the magnet 106 is magnetically oriented in the circumferential direction, the magnetic flux density of the radial component in the gap between the rotor 100 and the stator (not shown) is increased by the adjacent magnetic pole MP. The tendency to change sharply between the two becomes stronger, leading to an increase in torque ripple. Torque ripple is a cause of noise and vibration of the IPM type rotating electrical machine, and it is desirable that the torque ripple can be reduced as much as possible.

Japanese Patent Application Laid-Open No. 2014-082927

  In view of the above problems, an object of the present invention is to provide a rotor capable of reducing torque ripple as compared with the conventional one while suppressing a decrease in the amount of flux linkage of a magnet as much as possible.

  In order to achieve the above object, a rotor according to the present invention includes a cylindrical rotor core having a plurality of magnet holes and a plurality of core sheets made of electromagnetic steel plates, and filling each of the magnet holes. An end portion of each of the bonded magnets adjacent to the circumferential surface of the rotor core located on the q-axis side is tangent to an intersection of the q-axis and the circumferential surface, respectively. It is characterized by being magnetized in an oblique direction.

  In the rotor configured as described above, the bond magnet has a magnetic pole surface at a position closer to the d-axis than each of the end portions, and an average magnetic flux density of a radial direction component of the rotor core in the end portion is the magnetic pole. It may be characterized by being lower than the average magnetic flux density of the radial component on the surface.

  Further, when the average magnetic flux density at the magnetic pole surface is B1 and the average magnetic flux density at the end portion is B2, B1: B2 is 1: 0.5. .

  Further, the end portion may be characterized in that the width in the circumferential direction of the rotor core gradually increases as approaching the end surface closest to the peripheral surface of the end portion.

  Furthermore, the rotor core may have a bridge portion between the peripheral surface and an end surface closest to the peripheral surface of the end portion.

  According to the rotor of the present invention, each of the end portions of the magnet is magnetized in a direction oblique to the tangent at the intersection of the q axis and the peripheral surface of the rotor core, so that there is a gap between adjacent magnetic poles. A steep change in magnetic flux density can be mitigated, and torque ripple can be reduced as compared with the conventional case. Even if the end portion is magnetized in the direction, the gap magnetic flux density in the magnetic pole is almost the same as that in the conventional case, so that the amount of magnetic flux linkage of the magnet is not greatly reduced (almost) Not drop).

It is the front view which contains the rotor which concerns on embodiment (a) top view, and (b) AA line partial cut surface. It is the figure which expanded a part enclosed with the circular broken line of Fig.1 (a) partially. It is the graph which removed the slot harmonic for comparing the change of the gap magnetic flux density between the adjacent magnetic poles of the rotor and the conventional rotor. It is the elements on larger scale which show the (a) 1st modification of the edge part part of a bonded magnet, and (b) the 2nd modification. It is the (a) top view which shows the rotor which concerns on other embodiment, and the figure which expanded partially the part enclosed by the circular broken line of (b) (a). (A) The top view which shows the rotor for general IPM type | mold rotary electric machines, (b) It is the figure which expanded partially the part enclosed by the circular broken line of (a).

  Hereinafter, embodiments of a rotor according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the rotor 10 according to the embodiment includes a cylindrical rotor core 12. The rotor core 12 is provided with four magnet holes 14 penetrating in the axial direction. Each of the magnet holes 14 is filled with a bonded magnet (hereinafter simply referred to as “magnet”) 16. A hollow portion surrounded by the inner peripheral surface of the rotor core 12 is a shaft hole 18, and a rotation shaft RS is fitted into the shaft hole 18 so as to be coaxial with the rotor core 12. The rotor 10 which is a component of the IPM type rotating electrical machine (not shown) is disposed so as to face the stator (not shown) with a gap in the radial direction.

  The rotor core 12 is a laminated body in which a plurality of core sheets S are laminated. The core sheet S is made of an electromagnetic steel sheet in which a soft magnetic material is rolled into a thin plate shape having a thickness of about 0.2 to 1 mm (preferably about 0.3 to 0.5 mm) and the surface thereof is subjected to an insulation treatment. Each of the core sheets S has a hollow disk shape having a circular hole S8 at the center thereof. Each of the core sheets S is provided with four through holes S4 having the same shape in the circumferential direction at an equal pitch (at an interval of 90 degrees in mechanical angle). Each of the through holes S4 includes a strip-shaped long hole portion S41, and bent end portions S42 and S42 bent toward the outer peripheral portion side of the core sheet S from both longitudinal end portions of the long hole portion S41. In FIG. 1A, a through hole S4 (long hole portion S41, bent end portion S42) of the core sheet S located at the uppermost portion of the rotor core 12 is formed in the magnet hole 14 portion where the cross section appears in FIG. , S42).

  In the rotor core 12, the core sheets S are laminated so that the positions of the through holes S4 of the core sheets S adjacent in the axial direction are aligned, that is, the long hole portions S41 and the bent end portions S42 overlap each other. Has been. As a result, in the rotor core 12, one magnet hole 14 is formed by each of the through holes S4 that are communicated in the axial direction, and similarly configured magnet holes 14 are provided in the circumferential direction and the like. A total of four pieces are formed at a pitch (90-degree mechanical angle interval). Similarly, a shaft hole 18 is formed in the rotor core 12 by each of the circular holes S8 that are communicated in the axial direction.

  Each of the magnets 16 is obtained by filling a corresponding magnet hole 14 with a magnet material containing magnetic powder and a resin binder by injection molding, and magnetizing and curing the magnet material. Therefore, each of the magnets 16 has substantially the same shape as the corresponding magnet hole 14. Each of the magnets 16 has a flat plate-like main body portion 16A, and end portions 16B and 16B that are bent from both side ends of the main body portion 16A toward the outer peripheral surface of the rotor core 12, respectively. The main body portion 16A is a portion corresponding to the long hole portion S41 of each through hole S4 communicating in the axial direction. The end portion 16B is a portion corresponding to the bent end portion S42 of each through hole S4 communicating in the axial direction.

  Each of the magnets 16 is magnetized so that the magnetic pole surfaces 16N, 16S on the outer peripheral surface side of the main body portion 16A have different polarities (N pole, S pole) between the magnets 16 adjacent in the circumferential direction, It is composed of an anisotropic bonded magnet having a strong magnetic force in a direction perpendicular to the magnetic pole surfaces 16N and 16S. For the anisotropic bonded magnet, a magnet material having excellent magnetic properties mainly composed of neodymium (Nd), iron (Fe), and boron (B) is used. Each of the magnets 16 serves as a magnetomotive force source, and the rotor core 12 is magnetized. A four-pole magnetic pole MP in which N poles and S poles are alternately arranged in the circumferential direction is formed on the outer peripheral portion of the magnetized rotor core 12 facing the magnetic pole faces 16N and 16S.

  In the rotor 10, as shown in FIG. 1A, a line connecting the center of the magnetic pole MP and the axis of the rotor core 12 becomes the d axis, and connects the midpoint between the centers of the adjacent magnetic poles MP and the axis. The line is the q axis. In terms of the relationship with the magnet 16, the vertical bisector of the long side of the main body portion 16A becomes the d-axis, and the line connecting the midpoint between the adjacent end portions 16B of the adjacent magnets 16 and the axis. Becomes the q-axis. Therefore, the adjacent d-axes are offset by 90 degrees in mechanical angle and 180 degrees in electrical angle. Further, the adjacent d-axis and q-axis are shifted by 45 degrees in mechanical angle and 90 degrees in electrical angle. In FIG. 1A, the d-axis and the q-axis are indicated by a one-dot chain line and a two-dot chain line, respectively, and only the d-axis and q-axis necessary for the above description are shown.

  Each of the magnets 16 has magnetic pole surfaces 16N and 16S at positions closer to the d-axis than the respective end portions 16B. Each end portion 16 </ b> B of the magnet 16 is located on the q-axis side and is close to the outer peripheral surface of the rotor core 12. Each of the end portions 16B has a shape in which the width in the circumferential direction of the rotor core 12 is gradually increased (tapered) as it approaches the end surface EF (FIG. 2) closest to the outer peripheral surface. The width w of the end surface EF of the end portion 16B is larger than the width t of the main body portion 16A.

  Further, in this example, the rotor core 12 has a bridge portion 12B between the outer peripheral surface and each end surface EF of the end portion 16B. A portion (outer core) on the outer peripheral surface side and a portion (inner core) on the inner peripheral surface side are connected via the bridge portions 12B via the magnet 16 of the rotor core 12. Each of the bridge portions 12 </ b> B has a laminated structure in which thin electromagnetic steel plates that are part of the core sheet S are laminated in the axial direction, and constitutes part of the outer peripheral surface of the rotor core 12.

  In the rotor 10 having the above-described configuration, as shown in FIG. 2, each of the end portions 16 </ b> B that are adjacent to each other with the q-axis between the adjacent magnets 16 between the q-axis and the outer peripheral surface of the rotor core 12. It is magnetized in a direction oblique to the tangent TL at the intersection I (in this example, the direction in which the oblique angle θ with respect to the tangent TL is approximately 30 degrees). The oblique direction (arrow direction shown in FIG. 2) is hereinafter referred to as “magnetization direction”. The magnetic field in the end portion 16B is oriented in the magnetization direction of the end portion 16B. Of the bridge portion 12B facing the end surface EF of the end portion 16B by the orientation magnetic field formed by the end portion 16B, a portion corresponding to about half of the width w of the end surface EF from the magnetic pole MP side (hatched in FIG. 2) The portion shown is magnetized. The magnetized portion of the bridge portion 12B is hereinafter referred to as a “magnetized portion” and is denoted by a reference numeral “12BM”.

  Although not shown, in the rotor 10, the magnetization direction is also applied to each of the end portions 16B other than the portion shown in FIG. 2 (the portion surrounded by the circular broken line in FIG. 1A). In the same direction, that is, in a direction oblique to a tangent (not shown) at the intersection (not shown) of the q axis (not shown) nearest to the end portion 16B and the outer peripheral surface of the rotor core 12. Has been. The same applies to the oblique angle θ of the magnetization direction and each magnetization portion 12BM of the bridge portion 12B.

  In the rotor 10, between the magnetic pole surfaces 16N and 16S of the magnet 16 and the magnetic pole MP facing the magnetic pole surfaces 16N and 16S (portion corresponding to the outer core), magnet magnetic fluxes in the direction along the corresponding d-axis. The magnetic field which generate | occur | produces is formed. Magnet torque is generated by an attractive force / repulsive force acting between the magnetic field and a rotating magnetic field formed on the stator (not shown) side. In the case of the IPM type rotating electrical machine, reluctance torque is generated in addition to the magnet torque, so that a combined torque of each torque is output. At this time, as the magnetic flux density of the radial component in the gap between the rotor 10 and the stator (not shown) facing the rotor 10 (hereinafter referred to as “gap magnetic flux density”) is higher, the teeth (not shown) facing the magnetic pole MP are higher. The amount of interlinkage magnetic flux of the magnet 16 interlinking with the figure) also increases. On the other hand, as described above in the background art, if the gap magnetic flux density between adjacent magnetic poles MP tends to change sharply, torque ripple will increase.

  In this respect, in the rotor 10, as described above, a part of the magnet magnetic flux generated in the end portion 16B is bridged because the end portion 16B of the magnet 16 is magnetized in a direction oblique to the tangent line TL. Through the magnetized portion 12BM of the portion 12B, the teeth are linked to teeth (not shown) facing the main body portion 16A. Since the interlinkage magnetic flux via the magnetized portion 12BM is added, the gap magnetic flux density in each of the bridge portions 12B and 12B between the adjacent magnetic poles MP is increased, so that there is a steep change in the gap magnetic flux density between the adjacent magnetic poles MP. It is suppressed. In other words, the rotor 10 is configured such that the magnetized portion 12BM of the bridge portion 12B functions as a “second magnetic pole” having a magnetic force weaker than that of the magnetic pole MP.

  A change in the gap magnetic flux density of the conventional rotor 100 (FIG. 6) exemplified in the background art will be described with reference to FIG. 3, and the rotor 10 according to the embodiment (FIG. 1) looks like a comparison with the conventional rotor 100. And the characteristic regarding the change of the gap magnetic flux density of FIG. 2) is demonstrated.

  In the graph shown in FIG. 3, the change in the gap magnetic flux density per electrical angular period is indicated by a broken line in the conventional rotor 100 and a solid line in the rotor 10 of the embodiment. The position of the electrical angle of 180 degrees on the horizontal axis of the graph corresponds to the d-axis of N pole, and the position of electrical angle of 0 degrees and 360 degrees corresponds to the d-axis (not shown) of S pole. Further, the positions of the electrical angle of 90 degrees and 270 degrees correspond to the q axis between the adjacent magnetic poles MP (between the N pole and the S pole). In the graph, slot harmonics are removed.

  Here, for convenience of explanation, the horizontal axis (electrical angle 0 to 360 degrees) of the graph corresponding to one electrical angle period is divided into five sections from A section to E section shown on the upper side of the graph. Taking the conventional rotor 100 as an example, these five sections correspond to sections sectioned along the circumferential direction by double-ended arrows shown in FIG. Specifically, from the d-axis of the S pole to the circumferential and clockwise bridge portion 102B, the A section, from the terminal end of the A section to the N pole magnetic pole MP, the B section, and the N pole magnetic pole The entire MP section is the C section, the section from the terminal section of the C section to the magnetic pole MP of the S pole is the D section, and the d pole of the S pole that is different from the terminal section of the D section to the starting end section of the A section (S pole d axis). Up to the axis (not shown) is the E section. In addition, also in the rotor 10 of the embodiment, the sections A to E are the same as the sections described above, and therefore, the sections are not shown in FIG.

  Returning to FIG. 3, the change in the gap magnetic flux density of the conventional rotor 100 will be described first. In the conventional rotor 100, the gap magnetic flux density does not change in the A section, the C section, and the E section, and shows a constant value. Since the A section and the E section are the S poles and the C section is the N poles, the absolute values of the gap magnetic flux density are almost equal although the values of the gap magnetic flux density are different signs.

  On the other hand, in the B section and D section between adjacent magnetic poles MP, the gap magnetic flux density changes in a cubic function. For example, in the B section, the gap magnetic flux density changes steeply on the start end side, but the change becomes more gradual as the electrical angle advances and approaches the q-axis side. When the electrical angle further advances after the gap magnetic flux density becomes zero on the q axis, the change in the gap magnetic flux density is moderate, but the change becomes steeper as it approaches the terminal end side of the B section. Also, in the D section, like the B section, the gap magnetic flux density changes steeply on the start end side, but the change becomes more gradual as the electrical angle advances and approaches the q-axis side. When the electrical angle further advances after the gap magnetic flux density becomes zero on the q axis, the change in the gap magnetic flux density is moderate, but the change becomes steeper as it approaches the terminal end side of the D section.

  As described above, in the conventional rotor 100, in the B section and D section between adjacent magnetic poles MP, particularly at the start end side and the end end side where the polarity of the magnetic pole MP (N pole and S pole) changes. The gap magnetic flux density changes abruptly. This sharp change in the gap magnetic flux density contributes to an increase in torque ripple.

  Next, changes in the gap magnetic flux density of the rotor 10 according to the embodiment will be described in comparison with the conventional rotor 100. In the rotor 10 of the embodiment, although the value of the gap magnetic flux density in the A section, the C section, and the E section is slightly lower than that of the conventional rotor 100, the gap magnetic flux density in each section is the same as in the conventional rotor 100. It does not change and shows a constant value almost equivalent to the conventional one. That is, in the A section, the C section, and the E section, the gap magnetic flux density in each section can be regarded as having almost no difference between the rotor 10 of the embodiment and the conventional rotor 100.

  On the other hand, in the B section and the D section, there is a clear difference between the rotor 10 of the embodiment and the conventional rotor 100 regarding the change tendency of the gap magnetic flux density in each section. Specifically, the gap magnetic flux density in the B section and the D section changes in a cubic function in the conventional rotor 100, but in a linear function in the rotor 10 of the embodiment. That is, in the B section and the D section, the gap magnetic flux density changes almost uniformly (linearly) from the start end to the end. This change is due to the fact that the gap magnetic flux density in the bridge portions 12B and 12B between the adjacent magnetic poles MP is appropriately increased by the interlinkage magnetic flux through the magnetized portion 12BM.

  In the rotor 10 of the embodiment, the gap magnetic flux density is moderately increased at the bridge portions 12B and 12B between the adjacent magnetic poles MP because the end portion 16B of the magnet 16 is magnetized in the magnetization direction. As described above, the end portion 16B of the magnet 16 is magnetized in an oblique direction at an oblique angle θ of about 30 degrees with respect to the circumferential direction (tangential TL direction) between the adjacent magnetic poles MP (q axis). Yes. Therefore, based on the average magnetic flux density of the magnetization direction component of the end portion 16B, the average magnetic flux density of the radial direction (q-axis direction) component in the end portion 16B is about half of the magnetization direction component. On the other hand, the main body portion 16A of the magnet 16 is magnetized in the d-axis direction. Therefore, the average magnetic flux density of the radial direction (d-axis direction) component on the magnetic pole surfaces 16N and 16S of the main body portion 16A is substantially equal to the average magnetic flux density of the magnetization direction component serving as a reference. Looking at the magnet 16 as a whole, when the average magnetic flux density at the magnetic pole faces 16N and 16S is B1, and the average magnetic flux density at the end portion 16B is B2, the ratio B1: B2 of the average magnetic flux densities B1 and B2 is approximately: 1: 0.5.

  Thus, in the rotor 10 of the embodiment, the average magnetic flux density B2 of the end portion 16B is about half of the average magnetic flux density B1 of the magnetic pole surfaces 16N and 16S, and thus the bridge portion facing the end portion 16B. On average, the gap magnetic flux density at 12B can be set to about half the gap magnetic flux density at the magnetic pole MP facing the magnetic pole surfaces 16N and 16S. Thereby, the change of the gap magnetic flux density between the adjacent magnetic poles MP (B section and D section) becomes almost uniform, and the gap magnetic flux density distribution can be made close to a sine wave shape.

  In order to magnetize the end portion 16B of the magnet 16 in the above-described manner, for example, when the magnet 16 is injection-molded into each magnet hole 14 of the rotor core 12 using a known injection molding machine, a known magnetic field orientation mold is used. Is applied to the magnet 16 in a state where it is opposed to the region indicated by the circular arc arrow in FIG. 1 (a), that is, about half of the end face EF (FIG. 2) of the main body portion 16A and the end portions 16B and 16B. Can be magnetized.

  According to the rotor 10 of the above embodiment, each end portion 16B of the magnet 16 is magnetized in a direction oblique to the tangent TL at the intersection I between the q axis and the outer peripheral surface of the rotor core 12. A steep change in gap magnetic flux density between adjacent magnetic poles MP can be mitigated. Thereby, torque ripple can be reduced as compared with the conventional rotor 100. Even if the end portion 16B is magnetized in the above-described direction, the gap magnetic flux density in the magnetic pole MP is almost the same as that of the conventional rotor 100, so that the amount of interlinkage magnetic flux of the magnet 16 is greatly reduced. There is nothing (almost no decrease).

  In particular, if the end portion 16B of the magnet 16 is magnetized in a direction in which the oblique angle θ with respect to the tangent TL is approximately 30 degrees, the gap magnetic flux density distribution can be made closer to a sine wave. As a result, the effect of reducing torque ripple is further enhanced, and noise and vibration during driving of the IPM type rotating electrical machine can be effectively reduced.

  Further, since the width of the end portion 16B in the circumferential direction of the rotor core 12 gradually increases as it approaches the end surface EF of the end portion 16B, the magnetic field orientation mold for magnetizing the magnet 16 for production efficiency. This is advantageous in that it is easy to position.

  While the rotor 10 according to the embodiment has been described above, the present invention can be implemented in other forms. In the following description, components that are basically the same as those in the above embodiment are denoted by the same reference numerals or the same last digit, and a description of matters common to the above embodiments is simplified. We will stop referring to them or omit them as appropriate.

[First Modification]
The rotor 10 of the above embodiment is configured to have a bridge portion 12B between the outer peripheral surface of the rotor core 12 and each end surface EF of the end portion 16B. However, as shown in FIG. The end surface EF of the 16 end portions 16B may be a part of the outer peripheral surface of the rotor. Even in such a configuration, if the end portion 16B is magnetized in the same direction as the rotor 10 described above, the change in the gap magnetic flux density will show the same change as the graph shown in FIG.

[Second Modification]
In the rotor 10 of the above embodiment, the width of the end portion 16B in the circumferential direction of the rotor core 12 gradually increases as it approaches the end surface EF of the end portion 16B, but as shown in FIG. The portion 16B may have a uniform width. In short, the end portion 16B only needs to be magnetized in a direction oblique to the tangent TL at the intersection I between the q axis and the outer peripheral surface of the rotor core 12.

[Other Embodiments]
The rotor 10 of the above embodiment has four magnets 16 as magnetomotive force sources, and a total of four magnetic poles MP in which N poles and S poles are alternately arranged in the circumferential direction of the rotor core 12 are formed. The number of poles of the magnetic pole MP is not particularly limited as long as it is an even number. For example, as shown in FIG. 5, a rotor 20 having six magnets 26 and a total of six magnetic poles MP in which N poles and S poles are alternately arranged in the circumferential direction of the rotor core 22 is formed. You may implement with a form.

  In the rotor 20 according to another embodiment, adjacent d-axes are offset by 60 degrees in mechanical angle and 180 degrees in electrical angle, and the adjacent d-axis and q-axis are 30 degrees in mechanical angle and electrical angle. Will be shifted by 90 degrees. Further, each section partitioned along the circumferential direction by double-ended arrows shown in FIG. 5 corresponds to A to E sections corresponding to one electrical angle cycle of the rotor 20. Although the number of poles of the magnetic pole MP is different between the rotor 20 and the rotor 10 described above, the deviation of the electrical angle between the adjacent d-axes and between the d-axis and the q-axis is the same. Therefore, the change in the gap magnetic flux density per electrical angular period of the rotor 20 is the direction in which each end portion 26B of the magnet 26 obliquely intersects the tangent TL at the intersection I between the q axis and the outer peripheral surface of the rotor core 22 ( If it is magnetized in the direction of the arrow shown in FIG. 5B, the same change as the rotor 10, that is, the same change as the graph shown in FIG.

[Other variations]
(1) The shape of the magnet body portion is not limited to the above-described embodiments, that is, the “flat plate shape” of the body portion 16A of the magnet 16 and the “V shape” of the body portion 26 of the magnet 26. Other shapes such as “arc” and “W” may be used. Further, the end portion of the magnet does not have to be bent from one end of the main body portion, and may be a form (consisting of one end portion of the main body portion) that is remarkably integrated with the main body portion. . Further, the end portions adjacent to each other across the q axis of adjacent magnets are arranged such that the distance from the q axis gradually decreases toward the peripheral surface side of the rotor core (FIG. 2), parallel (parallel) to the q axis. Not only the extending form (FIG. 4), but also a form related to these combinations, that is, a form that extends in parallel (parallel) to the q axis after the distance from the q axis gradually decreases. It doesn't matter.

  (2) In each of the embodiments and the modifications described above, one magnetic pole is formed for one magnet, but one magnetic pole is formed by two or more magnets. It does not matter. Even in the rotor having the configuration, each of the plurality of magnets is located on the q-axis side, and the end portion adjacent to the outer peripheral surface of the rotor core is at the intersection of the q-axis and the outer peripheral surface of the rotor core, respectively. If magnetized in a direction oblique to the tangent, the change in the gap magnetic flux density will show the same change as the graph shown in FIG.

  (3) In each of the above-described embodiments and modifications, a neodymium-based magnet (mainly composed of neodymium (Nd), iron (Fe), boron (B)) as a magnet material for forming a magnet (bonded magnet) ( Nd-Fe-B magnets) are used, but magnets made of other magnet materials may be used. Other magnet materials include samarium-based magnets (Sm-Fe-N-based magnets), mainly composed of samarium (Sm), iron (Fe), and nitrogen (N), and composite materials of neodymium-based magnets and samarium-based magnets. Etc.

  (4) Each of the above-described embodiments and modification examples illustrate the inner rotor disposed on the inner peripheral side of the stator, but the present invention is applied to the outer rotor disposed on the outer peripheral side of the stator. Of course, it is also possible. In this case, each of the plurality of magnets, which are located on the q-axis side and close to the inner peripheral surface of the rotor core, respectively obliquely intersect with a tangent at the intersection of the q-axis and the inner peripheral surface. It will be magnetized in the direction.

  The present invention can be implemented in a mode in which various improvements, modifications, or variations are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention. Moreover, you may implement with the form which substituted any invention specific matter to the other technique within the range which the same effect | action or effect produces.

10, 20 Rotor 12, 22 Rotor core 14 Magnet hole 16, 26 Magnet 16B, 26B End portion I Intersection TL Tangent

Claims (5)

A cylindrical rotor core having a plurality of magnet holes and a plurality of core sheets made of electromagnetic steel plates are laminated;
A bonded magnet filled in each of the magnet holes;
With
Each of the bonded magnets is magnetized in an oblique direction with respect to a tangent line at the intersection of the q axis and the peripheral surface, in the vicinity of the peripheral surface of the rotor core located on the q axis side. Rotor characterized by being. The bond magnet has a magnetic pole surface at a position closer to the d-axis than the respective end portions;
The rotor according to claim 1, wherein an average magnetic flux density of a radial component of the rotor core at the end portion is lower than an average magnetic flux density of the radial component at the magnetic pole surface.   The rotor according to claim 2, wherein B1: B2 is 1: 0.5, where B1 is the average magnetic flux density at the magnetic pole surface and B2 is the average magnetic flux density at the end portion.   The width of the end portion in the circumferential direction of the rotor core gradually increases as the end portion approaches the end surface closest to the peripheral surface of the end portion. The rotor according to item.   The rotor according to any one of claims 1 to 4, wherein the rotor core includes a bridge portion between the peripheral surface and an end surface of the end portion that is closest to the peripheral surface. .

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