JP5228316B2 - Rotating electric machine rotor and rotating electric machine - Google Patents

Description

  The present invention relates to a rotor of a rotating electrical machine and a rotating electrical machine, and more particularly to a rotor of a rotating electrical machine having a permanent magnet embedded therein and the rotating electrical machine.

An embedded magnet type synchronous motor (so-called IPM motor) in which a permanent magnet is embedded in the core (iron core) of a rotor (rotor) can utilize reluctance torque by controlling the current phase, and control the current phase. By doing so, the maximum torque can be controlled. Conventionally, a structure for preventing irreversible demagnetization of a permanent magnet in an IPM motor has been disclosed (see Patent Document 1). In Patent Document 1, as shown in FIGS. 4 (a) and 4 (b), air is positioned so as to be located in the vicinity of the permanent magnets 52 </ b> A and 52 </ b> B arranged in a V shape that spreads toward the outer peripheral side of the rotor core 51. It is disclosed that holes 53A and 53B are formed to have a function of preventing irreversible demagnetization. The air holes 53A and 53B are formed so as to be located at the corners located on the d-axis side and on the outer peripheral side of the rotor core 51 of the permanent magnets 52A and 52B. Between the air holes 53A and 53B, the rotor core outer peripheral surfaces 53A-1 and 53B-1 are positioned between the magnet cores 54A and 54B and the rotor core outer peripheral surfaces 54A-1 and 54B-1 between the permanent magnets 52A and 52B. Of the permanent magnets 52A and 52B and the surfaces 52A-1 and 52B-1 on the outer periphery side of the rotor core. With this configuration, the magnetic flux that is short-circuited in the rotor core 51a between the permanent magnets 52A and 52B can be kept away from the corners b and c of the permanent magnets 52A and 52B, and acts on the corners b and c of the permanent magnets 52A and 52B. Since the local demagnetizing field is reduced, local irreversible demagnetization of the permanent magnets 52A and 52B can be prevented.
JP 2003-143788 A

  When considering the field-weakening control, which is an advantage of a so-called IPM motor in which a magnet is embedded in the rotor, the portion near the outer periphery of the rotor where the demagnetizing field applied to the magnet increases, that is, the portion corresponding to the q axis is irreversible It is necessary to consider demagnetization. However, Patent Document 1 considers only irreversible demagnetization of the portion corresponding to the d-axis.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a rotor for a rotating electrical machine and a rotating electrical machine capable of suppressing irreversible demagnetization of a permanent magnet in a portion near the outer periphery of the rotor. Is to provide.

In order to achieve the above object, according to the first aspect of the present invention, a plurality of permanent magnets are embedded in a rotor core of a rotor, and a flux barrier is continuously formed at an end of the permanent magnet on the q-axis side. The flux barrier is provided with an outer peripheral proximity portion that is closer to the outer periphery of the rotor than a portion of the permanent magnet that is closest to the outer periphery of the rotor, and the rotor core includes the permanent magnet from the outer peripheral proximity portion of the flux barrier. most whole to the part close to the rotor outer peripheral convex portion is formed so as to protrude toward the inner circumferential side rotor than extension from the rotor outer circumferential side of the outer portion of the permanent magnet, the convex The tip of the part is separated from the end of the permanent magnet on the q-axis side .

If the shape of the flux barrier formed continuously at the end on the q-axis side of the permanent magnet is such that there is no portion closer to the rotor outer periphery than the portion closest to the rotor outer periphery of the permanent magnet, the q-axis of the permanent magnet The magnetic flux traveling toward the flux barrier from the end on the side is bent so as to move away from the outer periphery of the rotor. For this reason, the magnetic flux proceeds in a direction in which the arrangement direction of the magnetic dipoles of the permanent magnet is disturbed, and irreversible demagnetization is likely to occur. However, in this invention, the flux barrier has an outer peripheral proximity portion closer to the rotor outer periphery than a portion of the permanent magnet closest to the rotor outer periphery, and the rotor core has the outer peripheral proximity portion of the flux barrier and the permanent magnet most rotated. A convex portion is formed between the portion close to the outer periphery of the rotor and projecting from the outer periphery of the rotor toward the inner periphery of the rotor rather than the extended line of the outer portion of the permanent magnet . Therefore, the magnetic flux traveling toward the flux barrier from the end on the q-axis side of the permanent magnet enters the convex portion of the rotor core from the flux barrier, and then proceeds between the outer peripheral proximity portion and the outer periphery of the rotor. . As a result, the magnetic flux is prevented from traveling in the direction in which the arrangement direction of the magnetic dipoles of the permanent magnet is disturbed, and irreversible demagnetization is unlikely to occur.

  The invention according to claim 2 is the invention according to claim 1, wherein the permanent magnet is formed in a flat plate shape and is magnetized in the thickness direction, and two pieces are provided per pole, and They are V-shaped and expand toward the outer peripheral side of the rotor, and are arranged so that the same side (for example, the outer peripheral side of the rotor) has the same polarity. In the present invention, the reluctance torque can be efficiently used as compared with a configuration in which the permanent magnet is arranged so as to extend in a direction orthogonal to the radial direction of the rotor.

  The invention according to claim 3 is the invention according to claim 1, wherein the permanent magnet is formed in a flat plate shape and magnetized in the thickness direction, one per pole, and It arrange | positions in the state extended in the direction orthogonal to the radial direction of a rotor. In the present invention, if the number of poles is the same, the number of permanent magnets is reduced compared to the V-shaped arrangement, and the assembly of the rotor is facilitated.

The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the outer peripheral proximity portion of the flux barrier is formed so as to be a curved surface convex outward , The portion of the flux barrier closest to the outer peripheral surface of the rotor is disposed on the extended line of the outer portion of the permanent magnet . In the present invention, the stress concentration is reduced as compared with the case where the outer peripheral proximity portion is not a curved surface.

  A rotating electrical machine according to a fifth aspect of the invention includes the rotor according to any one of the first to fourth aspects. The rotating electrical machine according to the present invention exhibits the effects and advantages of the invention according to any one of claims 1 to 5.

  ADVANTAGE OF THE INVENTION According to this invention, the rotor of a rotary electric machine and rotary electric machine which can suppress the irreversible demagnetization of the permanent magnet in the part close | similar to the outer periphery of a rotor can be provided.

(First embodiment)
Hereinafter, an embodiment in which the present invention is embodied in an electric motor will be described with reference to FIG. Fig.1 (a) is a schematic diagram corresponding to the half part of the whole rotor (rotor) and stator (stator) of an electric motor.

  As shown to Fig.1 (a), the stator 11 is cylindrical and the some teeth 12 are provided in the inner space at equal intervals. A coil (winding) 13 is wound around the tooth 12. The winding method of the coil 13 may be distributed winding or concentrated winding.

  A rotor is disposed inside the stator 11. The rotor 14 includes a rotor core 15 in which a plurality of disk-shaped electromagnetic steel plates (for example, several tens) are stacked, and a rotor shaft (rotating shaft) 16 inserted through the center of the rotor core 15. The rotor 14 is rotatably supported by a bearing of a housing (not shown) via a rotor shaft 16 with the outer peripheral surface of the rotor core 15 spaced apart from the teeth 12.

  As shown in FIGS. 1A and 1B, a plurality of permanent magnets 17 are embedded in the rotor core 15. The permanent magnet 17 is arranged in each virtual region obtained by equally dividing the rotor core 15 in the circumferential direction at an electrical angle of 360 °. In this embodiment, each permanent magnet 17 is formed in a flat plate shape having a rectangular cross section, and is magnetized so that the magnetization direction is the thickness direction. In addition, two permanent magnets 17 are provided for each pole, and the same side (for example, the outer peripheral side of the rotor 14) is widened toward the outer peripheral side of the rotor 14 so as to have the same polarity. Has been placed. Moreover, the permanent magnet 17 arrange | positioned at the adjacent virtual area | region is arrange | positioned so that the outer peripheral side of the rotor 14 may become a different pole. For example, when a set of V-shaped permanent magnets 17 are arranged so that the teeth 12 side is the S pole, the permanent magnets 17 arranged in the adjacent virtual region are arranged so that the teeth 12 side is the N pole. Placed in.

  The rotor 14 (rotor core 15) is provided with a flux barrier (hole) 18 that is continuous with the end of the permanent magnet 17 on the q-axis side. The flux barrier 18 has an outer peripheral proximity portion 18a closer to the rotor outer periphery than a portion 17a closest to the rotor outer periphery of the permanent magnet 17, and an outer peripheral proximity portion 18a and a portion 17a closest to the rotor outer periphery of the permanent magnet 17; In the meantime, it is formed in a shape having a portion 18b whose distance from the outer periphery of the rotor is longer on the inner peripheral side of the rotor than the extension line L of the outer portion of the permanent magnet 17. In this embodiment, the outer peripheral proximity portion 18 a is formed so as to exist on the extension line L of the outer portion of the permanent magnet 17.

  The flux barrier 18 does not face the entire surface of the end portion on the q-axis side of the permanent magnet 17 but does not face the end portion of the permanent magnet 17 closer to the inner side of the rotor 14. Further, the flux barrier 18 is formed so that the portion closest to the outer peripheral surface of the rotor 14, in this embodiment, the outer peripheral proximity portion 18 a is a curved surface convex outward. Adjacent permanent magnets 17 and flux barriers 18 are provided symmetrically with respect to a virtual plane including the center of the rotor 14.

  In the figure, the ratio of the sizes of the stator 11 and the rotor 14, the ratio of the sizes of the permanent magnet 17 and the flux barrier 18, the arrangement angle of the permanent magnet 17 and the like are different from the actual for convenience of illustration. .

  Next, the operation of the electric motor configured as described above will be described with reference to FIGS. FIG. 1C schematically shows the magnetic flux of the permanent magnet around the flux barrier 18 of the present embodiment, and FIG. 1D schematically shows the comparative example.

  When the motor is driven in a loaded state, the coil 13 of the stator 11 is energized and a rotating magnetic field acts on the rotor 14. As shown in FIGS. 1C and 1D, the rotor core 15 is in a state where magnetic flux (shown by a broken line) flows through the rotor outer peripheral portion of the permanent magnet 17. Since the amount of this magnetic flux is large, the magnetic flux generated from the permanent magnet 17 and going toward the outer periphery of the rotor is affected by the magnetic flux caused by energization of the coil 13. And as shown in FIG.1 (d), when the shape of the flux barrier 18 is a shape which leaves | separates from a rotor outer periphery rather than the part 17a nearest to a rotor outer periphery of the edge part of the permanent magnet 17, the permanent magnet 17 After the magnetic flux flowing through the rotor outer peripheral portion passes through the portion corresponding to the portion 17a, the magnetic flux spreads. As a result, the path of a part of the magnetic flux that is going to advance from the end of the permanent magnet 17 toward the outer periphery of the rotor is greatly bent so as to move away from the outer periphery of the rotor. For this reason, the magnetic flux proceeds in a direction in which the arrangement direction of the magnetic dipoles at the end on the q-axis side of the permanent magnet 17 is disturbed, and irreversible demagnetization is likely to occur.

  However, since the flux barrier 18 of this embodiment has the outer peripheral proximity portion 18a closer to the rotor outer periphery than the portion 17a closest to the rotor outer periphery of the permanent magnet 17, as shown in FIG. The magnetic flux flowing through the outer peripheral portion of the rotor 17 is in a state of flowing between the outer peripheral proximity portion 18a of the flux barrier 18 and the outer periphery of the rotor. Therefore, it is avoided that the path of a part of the magnetic flux to be advanced from the end on the q-axis side of the permanent magnet toward the outer periphery of the rotor is greatly bent so as to be separated (away from) the outer periphery of the rotor. Further, the flux barrier 18 is arranged between the outer peripheral proximity portion 18 a and the portion 17 a closest to the rotor outer periphery of the permanent magnet 17, and the rotor on the rotor inner peripheral side with respect to the extension line L of the outer portion of the permanent magnet 17. Since it is formed in a shape having a portion 18b that is far from the outer periphery, there is a convex portion in which a part of the rotor core 15 projects into the flux barrier 18 from the outer periphery of the rotor. Therefore, as shown in FIG. 1C, the magnetic flux traveling from the end on the q-axis side of the permanent magnet 17 toward the flux barrier 18 enters the convex portion of the rotor core 15 from the flux barrier 18, and then the outer peripheral proximity portion. It progresses toward between 18a and a rotor outer periphery. As a result, the magnetic flux is prevented from traveling in the direction in which the arrangement direction of the magnetic dipoles at the end on the q-axis side of the permanent magnet 17 is disturbed, and irreversible demagnetization is less likely to occur.

According to this embodiment, the following effects can be obtained.
(1) A plurality of permanent magnets 17 are embedded in the rotor 14, and a flux barrier 18 is provided in a state of being continuous with the end of the permanent magnet 17 on the q-axis side. The flux barrier 18 has an outer peripheral proximity portion 18a closer to the rotor outer periphery than a portion 17a closest to the rotor outer periphery of the permanent magnet 17, and a portion 17a closest to the rotor outer periphery of the outer peripheral proximity portion 18a and the permanent magnet 17 Are formed in a shape having a portion 18b whose distance from the outer periphery of the rotor is longer on the inner peripheral side of the rotor than the extension line L of the outer portion of the permanent magnet 17. Therefore, only by devising the shape of the flux barrier 18, it is possible to suppress the magnetic flux from traveling in a direction in which the arrangement direction of the magnetic dipoles is disturbed in the portion near the outer periphery of the rotor 14 of the permanent magnet 17, and irreversible demagnetization is prevented. It becomes difficult to occur, and irreversible demagnetization of the permanent magnet 17 in a portion close to the outer periphery of the rotor 14 can be suppressed.

  (2) The permanent magnet 17 is formed in a flat plate shape, and two magnets magnetized in the thickness direction are provided for each pole, and the V shape is the same as the V shape that expands toward the outer peripheral side of the rotor 14. It arrange | positions so that the side may become the same pole. Therefore, the reluctance torque can be efficiently used as compared with a configuration in which the permanent magnet 17 is arranged so as to extend in a direction orthogonal to the radial direction of the rotor 14.

  (3) The flux barrier 18 is formed such that the outer peripheral proximity portion 18a closest to the outer peripheral surface of the rotor 14 has a curved surface protruding outward. Therefore, when the rotor 14 is assembled and used in an electric motor, stress concentration caused by centrifugal force is alleviated when the rotor 14 rotates compared to when the outer peripheral proximity portion 18a is not a curved surface.

(4) Since the permanent magnet 17 is formed in a flat plate shape having a rectangular cross section, the manufacture is easy.
The embodiment is not limited to the above, and may be embodied as follows, for example.
If the flux barrier 18 is provided in a state of being continuous with the end of the permanent magnet 17 on the q-axis side, the arrangement of the permanent magnet 17 is not limited to the V shape. For example, as shown in FIGS. 2A and 2B, the permanent magnet 17 is formed in a flat plate shape and magnetized in the thickness direction, one piece per pole, and the rotor. The structure arrange | positioned in the state extended in the direction orthogonal to 14 radial directions may be sufficient. In this case, if the number of poles is the same, the number of permanent magnets 17 is reduced as compared with the V-shaped arrangement, and the assembly of the rotor 14 is facilitated.

  The permanent magnet 17 is not limited to a flat plate shape, and may be a plate shape curved in an arc shape in the thickness direction. For example, as shown in FIGS. 3A and 3B, one permanent magnet 17 per pole may be provided in a state where the outer peripheral side of the rotor is concave. In this case, compared with the case where two flat permanent magnets 17 are arranged in a V shape, it is preferable for the flow of magnetic flux, but from the viewpoint of ease of manufacturing and handling of the permanent magnet 17, The V-shaped arrangement of the flat permanent magnets 17 is preferable.

  In the case where one flat permanent magnet 17 is provided per pole, the permanent magnet 17 is not necessarily limited to the configuration arranged in a state orthogonal to the radial direction, and may be arranged in a slightly inclined state.

  The outer peripheral proximity portion 18a does not need to be formed on the extension line L of the outer portion of the permanent magnet 17, and is closer to the rotor outer periphery than the portion 17a of the permanent magnet 17 closest to the rotor outer periphery. If so, the extension line L may be closer to the outer periphery of the rotor or the extension line L may be further to the outer periphery of the rotor.

The permanent magnet 17 is not limited to a rectangular cross section, and may have a shape in which semicircles are continuous at both ends of the rectangle or a shape in which triangles are continuous at both ends of the rectangle.
○ Among the flux barriers 18, only the flux barrier 18 formed at a position corresponding to the end on the q-axis side of the permanent magnet 17 arranged so that the N pole is on the rotor outer peripheral side, the outer peripheral proximity portion 18a and the permanent You may form in the shape which has the part 18b in which the distance from a rotor outer periphery becomes far in the rotor inner peripheral side with respect to the extension line L of the outer side part of the magnet 17. FIG. In the case of the permanent magnet 17 arranged so that the south pole is on the rotor outer peripheral side, since there is no magnetic flux traveling from the end of the permanent magnet on the q-axis side toward the rotor outer periphery, the outer peripheral proximity portion 18a and the portion 18b are provided. The flux barrier 18 having a shape as shown in FIG. However, since the labor for forming the rotor core 15 is hardly changed, the flux barrier 18 provided at a position corresponding to the end on the q-axis side of the permanent magnet 17 is not limited to the magnetization direction of the permanent magnet 17, and the outer peripheral proximity portion 18 a and The formation of the shape having the portion 18b reduces the labor for assembling the permanent magnet 17 to the rotor core 15.

The flux barrier 18 is not limited to holes (voids) but may be filled with resin.
○ The number of poles of the electric motor is not limited to eight but may be an even number, but four or more are preferable.
○ It may be applied not only to motors but also to generators.

The following technical idea (invention) can be understood from the embodiment.
(1) In the invention according to any one of claims 1 to 5, the flux barrier includes an end on the q-axis side of a permanent magnet arranged so that the north pole is on the rotor outer peripheral side. It is provided only at the corresponding position.

(A) is the partial schematic diagram which shows the relationship between the rotor and stator of one Embodiment, (b) is the elements on larger scale of (a), (c) is a schematic diagram explaining an effect | action, (d) is an effect | action of a comparative example. FIG. (A) is the partial schematic diagram which shows the relationship between the rotor and stator of another embodiment, (b) is the elements on larger scale of (a). (A) is the partial schematic diagram which shows the relationship between the rotor and stator of another embodiment, (b) is the elements on larger scale of (a). (A) is a schematic diagram of the core of a prior art, (b) is the elements on larger scale of (a).

Explanation of symbols

  L ... extension line, 14 ... rotor, 17 ... permanent magnet, 17a, 18b ... part, 18 ... flux barrier, 18a ... outer peripheral proximity part.

Claims (5)

A plurality of permanent magnets are embedded in the rotor core of the rotor, and a flux barrier is provided in a state of being continuous with the q-axis end of the permanent magnet, and the flux barrier is disposed on the outermost rotor periphery of the permanent magnet. It has an outer peripheral proximity part that is closer to the outer periphery of the rotor than a close part,
In the rotor core, the entire area from the outer peripheral proximity portion of the flux barrier to the portion closest to the outer periphery of the permanent magnet is closer to the rotor inner peripheral side than the extension line of the outer portion of the permanent magnet from the rotor outer peripheral side. The rotor of the rotating electrical machine is characterized in that a protrusion is formed so as to protrude toward the end, and the tip of the protrusion is separated from the end on the q-axis side of the permanent magnet .   The permanent magnet is formed in a flat plate shape and is magnetized in the thickness direction, and two magnets are provided per pole. The permanent magnet is V-shaped and expands toward the outer peripheral side of the rotor. The rotor of the rotating electrical machine according to claim 1, wherein the rotor is arranged to be.   The permanent magnet is formed in a flat plate shape and magnetized in the thickness direction, one per magnet is provided, and is disposed in a state extending in a direction perpendicular to the radial direction of the rotor. Item 2. A rotating electrical machine rotor according to Item 1. The outer peripheral proximity portion of the flux barrier is formed so as to have a convex curved surface outward, and the portion closest to the outer peripheral surface of the rotor of the flux barrier is disposed on an extension line of the outer portion of the permanent magnet. the rotor of a rotary electric machine according to any one of claims 1 to 3 which are.   The rotary electric machine provided with the rotor as described in any one of Claims 1-4.

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