JP2010279184A - Rotor for axial gap type rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-efficient and inexpensive rotor for axial gap type rotary electric machines. <P>SOLUTION: The rotor 10 for axial gap type rotary electric machines includes a frame 1 capable of rotating with the axis of rotation as the center, and a plurality of field sections 2 that are arranged around a rotation axis center C of the frame 1 and include a magnetic pole surface on an axial end face. At each field section 2, a plurality of permanent magnet pieces 211, 212 including rectangular magnetic pole surfaces are arranged so that width W1 at the outer-periphery side of the frame 1 becomes larger than that W2 at the side of the rotation axis center C. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rotor for an axial gap type rotating electrical machine.

  An axial gap type rotating electrical machine is a rotating electrical machine including a rotor that is arranged to be rotatable about a rotation axis and a stator that is arranged with a gap in the direction of the rotation axis of the rotor. An axial gap type rotating electrical machine is preferable to rotating electrical machines of other structures in that the structure can be reduced in thickness and the magnetic pole area can be increased to improve the torque density.

  Patent Document 1 below describes that a rare earth sintered magnet formed by a vertical magnetic field press is used as a permanent magnet constituting a field part of a rotor of an axial gap type rotating electrical machine. The vertical magnetic field press is a method of press-molding magnet powder by applying a magnetic field in a direction perpendicular to the press direction, and can reduce disturbance in the orientation of the magnet powder compared to a parallel magnetic field press in which a magnetic field is applied parallel to the press direction. A permanent magnet having excellent magnetic properties can be obtained.

JP 2009-33946 A, paragraph “0019”

  However, the permanent magnet formed by the vertical magnetic field press is formed into a rectangular parallelepiped shape because of applying a magnetic field in a direction perpendicular to the press direction, and the magnetic pole surface has a rectangular shape. Therefore, in order to maximize the magnetic pole area of the rotor of the axial gap type rotating electric machine, it is necessary to make the magnetic pole surface of each field part substantially fan-shaped. When a magnet is used, the rectangular parallelepiped permanent magnet must be cut into a substantially fan shape, which wastes magnet material and increases the manufacturing cost of the rotor.

  The present invention has been made in view of the above-mentioned drawbacks in a conventional axial gap type rotating electrical machine rotor using a permanent magnet formed by a vertical magnetic field press, and is a highly efficient and inexpensive axial gap. It aims at providing the rotor for type | mold rotary electric machines.

The present invention relates to an axial gap type rotation including a frame rotatable around a rotation axis, and a plurality of field portions disposed around the rotation axis of the frame and having a magnetic pole surface on an axial end surface. An electric rotor,
Each of the field portions is configured by arranging a plurality of permanent magnet pieces having rectangular magnetic pole surfaces so that the width on the outer peripheral side of the frame is larger than the width on the rotation axis side. .

  In addition, in this application, a rectangle means a rectangle or a square. In addition, minute chamfering and rounding of the corners are arbitrary.

  Further, the present invention is characterized in that each of the field portions includes a substantially fan-shaped magnetic core superimposed on the magnetic pole surfaces of the plurality of permanent magnet pieces.

  Further, the present invention is characterized in that a concave portion or a convex portion for positioning the permanent magnet piece is provided on a surface of the magnetic core that contacts the permanent magnet piece.

  Further, the present invention is characterized in that magnetic poles are disposed between the plurality of field portions at predetermined intervals along the side edge shape of each field portion.

  In addition, the present invention is characterized in that each of the field magnet portions includes a magnetic core having substantially the same shape as the overall shape of the plurality of permanent magnet pieces, which is superimposed on the plurality of permanent magnet pieces.

  Further, the present invention is characterized in that the permanent magnet pieces are arranged in a circumferential direction of the frame.

  Further, according to the present invention, three or more of the permanent magnet pieces are arranged in the circumferential direction of the frame, and the residual magnetic flux density of the permanent magnet pieces on both outer sides in the circumferential direction of the frame is set on the inner side in the circumferential direction of the frame. It is characterized by being smaller than the residual magnetic flux density of the permanent magnet piece.

  Further, according to the present invention, three or more of the permanent magnet pieces are arranged in the circumferential direction of the frame, and the coercive force of the permanent magnet pieces on both outer sides in the circumferential direction of the frame It is characterized by being larger than the coercive force of the magnet piece.

  Further, the present invention is characterized in that the coercive force of the permanent magnet piece on the reverse side in the rotational direction of the frame is larger than the coercive force of the permanent magnet piece on the forward side in the rotational direction of the frame.

  Further, the present invention is characterized in that the permanent magnet pieces are arranged in the radial direction of the frame.

  Further, the present invention is characterized in that the residual magnetic flux density of the permanent magnet piece on the outer peripheral side of the frame is larger than the residual magnetic flux density of the permanent magnet piece on the rotational axis side of the frame.

  Further, the present invention is characterized in that the coercive force of the permanent magnet piece on the rotation axis side of the frame is larger than the coercive force of the permanent magnet piece on the outer peripheral side of the frame.

  Further, the present invention is characterized in that the permanent magnet piece is an Nd—Fe—B based sintered magnet.

  In the rotor for an axial gap type rotating electrical machine according to the present invention, a plurality of permanent magnet pieces each having a plurality of field portions each having a rectangular magnetic pole surface, the width on the outer peripheral side of the frame is larger than the width on the rotation axis side. The permanent magnets that are formed by vertical magnetic field press to form a rectangular parallelepiped shape can be used without cutting into a substantially fan shape, for example, so that the axial shaft is highly efficient and inexpensive. A rotor for a gap type rotating electrical machine can be provided.

  In addition, since each field portion is configured by arranging a plurality of permanent magnet pieces, for example, a plurality of permanent magnet pieces having different characteristics such as residual magnetic flux density and coercive force can be easily combined as necessary. In addition, a more efficient axial gap type rotating electrical machine rotor can be provided.

It is a schematic sectional drawing of the axial gap type rotary electric machine provided with the rotor of this embodiment. It is a perspective view of the decomposition | disassembly state of the rotor of this embodiment. It is a top view of the assembly state of the rotor of this embodiment. It is principal part sectional drawing explaining the arrangement | sequence state of the several permanent magnet piece in the rotor of this embodiment. It is explanatory drawing of the arrangement state of the several permanent magnet piece in the modification of the rotor which concerns on this invention. It is explanatory drawing of the arrangement state of the several permanent magnet piece in the other modification of the rotor which concerns on this invention. It is explanatory drawing of the arrangement state of the several permanent magnet piece in the further another modification of the rotor which concerns on this invention. It is explanatory drawing which shows the shape of the magnetic body magnetic pole in the further another modification of the rotor which concerns on this invention. It is a principal part perspective view which shows the convex part and the recessed part for positioning the permanent magnet piece in the further another modification of the rotor which concerns on this invention.

  The rotor according to the present invention is used for an axial gap type rotating electrical machine. As shown in the schematic diagram of FIG. 1, the axial gap type rotating electrical machine 100 includes a rotor 10 disposed so as to be rotatable about a rotating shaft 40 (rotating axis C), and both sides of the rotor 10 in the rotating shaft direction. The first stator 20 and the second stator 30 are provided with a predetermined gap therebetween. The first stator 20 includes a back yoke 201, a tooth 202 erected on the back yoke 201, and a coil 203 wound around the tooth 202, and the second stator 30 includes a back yoke 301. Has been. The first stator 20 and the second stator 30 are fixed to a container (not shown), and the rotation shaft 40 penetrates through the rotation shaft 40 in a rotatable manner.

  As shown in FIGS. 1 to 3, the rotor 10 of the present embodiment is fixed to a rotary shaft 40 and is composed of a frame 1 made of a nonmagnetic material that can rotate around a rotary axis C, and a rotary shaft of the frame 1. A plurality of field portions 2 having a magnetic pole face at the axial end face, a plurality of magnetic poles 3 similarly arranged around the rotation axis C, and the plurality of field magnets. It comprises a pressing member 4 that fixes the portion 2 and the magnetic pole 3 to the frame 1.

  As shown in the exploded perspective view of FIG. 2, the frame 1 projects radially from an inner peripheral portion 12 having a shaft hole 11 into which a rotary shaft 40 (not shown) can be inserted, and an outer surface of the inner peripheral portion 12. Spoke portion 13 and an outer peripheral portion 14 provided at the tip of the spoke portion 13. The outer surface of the inner peripheral portion 12, the side surface of each spoke portion 13, and the inner periphery of the outer peripheral portion 14 There are a total of six field part holding holes 15 partitioned by the side surface. Each spoke portion 13 is formed with a magnetic pole holding hole 16 for holding the plate-like magnetic magnetic pole 3.

  As shown in FIG. 2, the field portion 2 is superposed on the permanent magnet portion 21 held in the field portion holding hole 15 of the frame 1 and the permanent magnet portion 21, and the same field portion holding hole 15. And a substantially fan-shaped magnetic core 22 held inside. As shown in FIG. 4, the permanent magnet portion 21 rotates a plurality of permanent magnet pieces 211 and 212 having rectangular magnetic pole surfaces with a circumferential width W1 on the outer peripheral side (outer peripheral portion 14 side) of the frame 1. They are arranged side by side so as to be larger than the circumferential width W2 on the axis C side (inner peripheral part 12 side). Here, the magnetic body of the magnetic body core 22 refers to a soft magnetic body such as iron.

  These permanent magnet pieces 211 and 212 are made of Nd—Fe—B (neodymium / iron / boron) sintered magnets formed by a vertical magnetic field press, and are formed in a rectangular parallelepiped shape. This rare earth sintered magnet has high electrical conductivity, and eddy current loss is likely to occur due to the rotating magnetic field generated from the first stator 20. For this reason, the magnetic core 22 is made of a magnetic material having a lower electrical conductivity than that of the rare earth magnet, and the eddy current loss can be reduced by disposing the permanent magnet portion 21 on the first stator 20 side. In particular, when PWM control is performed, eddy current loss due to a change in high-frequency magnetic flux of the carrier component can be reduced. Further, if the magnetic core 22 is composed of a magnetic core having magnetic isotropy, eddy current loss can be hardly caused in the magnetic core 22. Further, since most of the field magnetic flux generated by the permanent magnet portion 21 on the first stator 20 side passes through the magnetic core 22, the surface on the first stator 20 side of the substantially fan-shaped magnetic core 22 is substantially Thus, it functions as a polar magnetic surface of the field part 2.

  Further, in the present embodiment, as shown in FIG. 4, each permanent magnet portion 21 is configured by arranging two large and small permanent magnet pieces 211 and 212 in the radial direction of the frame 1. Then, the residual magnetic flux density (Br) of the permanent magnet piece 211 on the outer peripheral side (outer peripheral portion 14 side) of the frame 1 is set to the residual magnetic flux of the permanent magnet piece 212 on the rotational axis C side (inner peripheral portion 12 side) of the frame 1. It is larger than the density. This is because the circumferential width of the teeth 202 of the first stator 20 becomes smaller toward the rotation axis C side of the frame 1 (the teeth are smaller than the ratio of the width of the outer circumference and the inner circumference of the magnet due to the winding). This is because the ratio of the width of the outer periphery and the inner periphery of 202 is larger), and magnetic saturation is likely to occur, while the larger the diameter is on the outer periphery side of the frame 1, the greater the torque.

  In the present embodiment, the coercive force (Hc) of the permanent magnet piece 212 on the rotation axis C side (inner peripheral portion 12 side) of the frame 1 is used as the permanent magnet piece on the outer peripheral side (outer peripheral portion 14 side) of the frame 1. It is larger than the coercive force of 211. As a result, the magnetic path is shorter and more easily demagnetized toward the rotation axis C of the frame 1, and this can be dealt with.

  As shown in FIG. 4, the magnetic pole 3 is accommodated in a magnetic pole holding hole 16 formed in each spoke portion 13 of the frame 1. The magnetic pole 3 is made of a soft magnetic material, and increases the reluctance torque generated due to the difference between the q-axis inductance and the d-axis inductance by increasing the so-called q-axis inductance.

  As shown in FIGS. 1 and 2, the holding member 4 is held in the field portions 2 held in the plurality of field portion holding holes 15 of the frame 1 and in the plurality of magnetic pole holding holes 16, respectively. The magnetic pole 3 is fixed to the frame 1. In the present embodiment, the plurality of field portions 2 and the magnetic poles 3 are fixed by laser welding the pressing members 4 on both sides of the frame 1 in the direction of the rotation axis C.

  In the present embodiment, the holding member 4 that fixes the field portion 2 and the magnetic pole 3 on the first stator 20 side of the frame 1 is formed of a small-diameter ring component 41 and a large-diameter ring component 42. A pressing member 4 that fixes the field portion 2 and the magnetic pole 3 on the second stator 30 side of the frame 1 is formed from a disk component 43. As shown in FIG. 1, a small-diameter ring component 41 is laser welded to the frame 1 in a state where a part of the inner edge of the magnetic pole surface on the first stator 20 side of the field magnet portion 2 is pressed. 42 is laser welded to the frame 1 in a state where a part of the outer edge of the magnetic pole surface of the field portion 2 on the first stator 20 side is pressed. The disk component 43 is laser welded to the frame 1 in a state where the entire magnetic pole surface on the second stator 30 side of the field part 2 is pressed. The joining means is not limited to laser welding, and different means such as fastening with rivets may be used.

  The disk component 43 is formed of a soft magnetic electromagnetic steel plate and has a function of partially short-circuiting the magnetic flux on the second stator 30 side of the field part 2. With this function, when the magnetic attractive force acting between the second stator 30 and the rotor 10 is stronger than the magnetic attractive force acting between the first stator 20 and the rotor 10, the second stator 30 and the rotor 10 The magnetic attractive force acting during If this function is unnecessary, a ring component may be used instead of the disk component 43.

  Magnetization of the permanent magnet portion 21 of the field magnet portion 2 may be performed after the field magnet portion 2 is fixed to the frame 1 by the pressing member 4 or may be performed before the magnet is fixed. Magnetization is preferable in terms of handling the permanent magnet pieces 211 and 212. This is because, since repulsive forces act on each other, it is difficult to arrange the permanent magnet pieces 211 and 212 after magnetization.

  As described above, in the rotor 10 for an axial gap type rotating electrical machine of the present embodiment, the plurality of field magnet portions 2 each have a plurality of permanent magnet pieces 211 and 212 each having a rectangular magnetic pole surface. Because it is arranged side by side so that it is larger than the width on the rotation axis side, permanent magnets that are formed with a vertical magnetic field press and have a rectangular parallelepiped shape do not cut into a substantially fan shape, for example. However, it is possible to provide a highly efficient and inexpensive rotor for an axial gap type rotating electrical machine.

  Moreover, since each field portion 2 is configured by arranging a plurality of permanent magnet pieces, a plurality of permanent magnet pieces having different characteristics such as residual magnetic flux density and coercive force can be easily combined as necessary. Thus, it is possible to provide a highly efficient rotor for an axial gap type rotating electrical machine.

  The axial gap type rotor for the rotating electrical machine according to the present embodiment has been described above, but the present invention can be implemented in other forms.

  For example, in the above embodiment, the large and small permanent magnet pieces 211 and 212 are arranged in the radial direction of the frame in each field part holding hole 15 of the frame 1, but the present invention is of course not limited thereto. As shown in FIG. 5A, the field portion may be configured by arranging three permanent magnet pieces 213A, 213B, and 213C of equal width in the field portion holding hole 15 in the radial direction of the frame. Further, as shown in FIG. 5B, the field portion may be configured by arranging six permanent magnet pieces 214 </ b> A to 214 </ b> F of equal width in the field direction holding hole 15 in the radial direction of the frame. . These equal-width permanent magnet pieces having different lengths can be obtained by dividing the rectangular parallelepiped permanent magnet pieces as they are or in the longitudinal direction thereof, so that the rotor can be manufactured at a lower cost.

  Further, as shown in FIG. 6, for example, three permanent magnet pieces 215 </ b> A to 215 </ b> C may be arranged in the circumferential direction of the frame in the field holding hole 15 of the frame to constitute the field portion. Thus, when arranging a plurality of permanent magnet pieces having rectangular (rectangular and square) magnetic pole faces in the circumferential direction of the frame, the residual magnetic flux density of the permanent magnet pieces 215A and 215C on both outer sides in the circumferential direction of the frame is It is preferable to make it smaller than the residual magnetic flux density of the permanent magnet piece 215B on the inner side in the circumferential direction of the frame. Thus, the air gap magnetic flux density can be distributed close to a sine wave, and the induced voltage can be converted to a sine wave to reduce torque ripple.

  Further, it is preferable that the coercive force of the permanent magnet pieces 215A and 215C on both outer sides in the circumferential direction of the frame is larger than the coercive force of the permanent magnet piece 215B on the inner side in the circumferential direction of the frame. Thus, the permanent magnet pieces on both outer sides in the circumferential direction of the frame are more easily demagnetized, and this can be dealt with.

  Further, it is preferable that the coercive force of the permanent magnet piece 215C on the reverse side in the rotational direction of the frame is larger than the coercive force of the permanent magnet piece 215A on the forward side in the rotational direction of the frame. As a result, the permanent magnet piece on the reverse side in the rotational direction of the frame has a large reverse magnetic field at the time of driving and can be easily demagnetized.

  Further, as shown in FIG. 7, for example, three permanent magnet pieces 216 </ b> A to 216 </ b> C may be arranged in an oblique direction with respect to the radial direction of the frame in the field holding hole 15 of the frame to constitute the field portion. good. As described above, the number of permanent magnet pieces constituting the rotor field portion, the arrangement direction, the size of each permanent magnet piece, the combination of magnetic characteristics, etc., the performance required for the axial gap type rotating electrical machine, etc. Various design changes are possible depending on the situation.

  In addition, as shown in FIG. 8, magnetic poles 6 may be disposed between the plurality of field portions 2 at a predetermined interval along the side edge shape of each field portion 2. That is, the rotor frame 5 of the modified example shown in FIG. 8 includes an inner peripheral portion 52 having a shaft hole 51, sawtooth-shaped spoke portions 53 projecting radially from the outer surface of the inner peripheral portion 52, and The outer peripheral portion 54 provided at the tip of the spoke portion 53 is composed of a total of 6 divided by the outer surface of the inner peripheral portion 52, the side surface of each spoke portion 53, and the inner side surface of the outer peripheral portion 54. Two convex field part holding holes 55 are provided. Each spoke portion 53 is formed with a sawtooth-shaped magnetic pole holding hole 56 through a wall portion having a constant thickness. Large and small permanent magnet pieces 211 and 212 are accommodated side by side in the field portion holding hole 55 of the frame 5 with almost no gap, and the sawtooth magnetic pole 6 is accommodated in the magnetic pole holding hole 56 with almost no gap. Has been. This makes it possible to use the reluctance torque more efficiently. In this case, each field part 2 may include a magnetic core having substantially the same shape as the overall shape (convex shape) of the plurality of permanent magnet pieces 211 and 212 superimposed on the plurality of permanent magnet pieces 211 and 212. good.

  In addition, as shown in FIG. 9, in each field portion, a concave or convex portion for positioning the permanent magnet pieces 211 and 212 may be provided on the surface where the plurality of permanent magnet pieces 211 and 212 of the magnetic core 22 are in contact. good. That is, as shown in FIG. 9A, a recess 221 is formed in the magnetic core 22, and a plurality of permanent magnet pieces 211 and 212 are fitted into the recess 221 to position the permanent magnet pieces 211 and 212. Alternatively, as shown in FIG. 9B, a plurality of convex portions 222 are formed on the magnetic core 22, and a plurality of permanent magnet pieces 211 and 212 are fitted between the convex portions 222 for positioning. You may do. Thus, a plurality of permanent magnet pieces can be combined and fixed to the frame more stably and reliably. In FIG. 9, the magnetic core 22 is greatly deformed and drawn with respect to the permanent magnet pieces 211 and 212, but in reality, it is sufficient that the permanent magnet pieces 211 and 212 are circumscribed.

  Moreover, in the said embodiment, although the several permanent magnet pieces 211 and 212 are accommodated in the field part holding hole 5 of the flame | frame 1, and it fixes with the pressing member 4, this invention is not limited to this. For example, a plurality of permanent magnet pieces may be fixed to a disk-shaped frame using an adhesive.

  In addition, the present invention can be carried out in a mode in which various improvements, modifications and variations are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It may be implemented in a form in which any invention specific matter is replaced with another technology within a range where the same action or effect occurs, or the invention specific matter configured integrally may be constituted by a plurality of members. In addition, the invention specific items constituted by a plurality of members may be implemented in an integrated configuration.

DESCRIPTION OF SYMBOLS 100: Axial gap type rotary electric machine 10: Rotor 1: Frame 2: Field part 21: Permanent magnet part 211, 212, 213A-213C, 214A-214F, 215A-215C, 216A-216C: Permanent magnet piece 22: Magnetic body Core 221: Concave portion 222: Convex portion 3: Magnetic pole 4: Pressing member 20: First stator 30: Second stator 40: Rotating shaft C: Rotating shaft center W1: Width W2 on the outer periphery side of the field portion at the frame The width of the magnetic part on the frame rotation axis side

Claims (13)

A rotor for an axial gap type rotating electrical machine, comprising: a frame rotatable around a rotation axis; and a plurality of field portions disposed around an axis of rotation of the frame and having a magnetic pole surface on an axial end surface. There,
Each of the field portions is configured by arranging a plurality of permanent magnet pieces having rectangular magnetic pole faces toward the axial end face so that the width on the outer peripheral side of the frame is larger than the width on the rotation axis side. A rotor for an axial gap type rotating electrical machine.   2. The rotor for an axial gap type rotating electrical machine according to claim 1, wherein each field portion includes a substantially fan-shaped magnetic core superimposed on the plurality of permanent magnet pieces.   3. The rotor for an axial gap type rotating electrical machine according to claim 2, wherein a concave portion or a convex portion for positioning the permanent magnet piece is provided on a surface of the magnetic core that contacts the permanent magnet piece.   2. The rotor for an axial gap type rotating electrical machine according to claim 1, wherein magnetic poles are disposed between the plurality of field portions at predetermined intervals along a side edge shape of each field portion.   5. The axial gap type rotating electrical machine according to claim 4, wherein each of the field portions includes a magnetic core that is overlapped with the plurality of permanent magnet pieces and has substantially the same shape as the overall shape of the plurality of permanent magnet pieces. Rotor.   The rotor for an axial gap type rotating electrical machine according to any one of claims 1 to 5, wherein the permanent magnet pieces are arranged in a circumferential direction of the frame. Three or more permanent magnet pieces are arranged in the circumferential direction of the frame;
The rotor for an axial gap type rotating electrical machine according to claim 6, wherein the residual magnetic flux density of the permanent magnet pieces on both outer sides in the circumferential direction of the frame is smaller than the residual magnetic flux density of the permanent magnet pieces on the inner side in the circumferential direction of the frame. Three or more permanent magnet pieces are arranged in the circumferential direction of the frame;
The rotor for an axial gap type rotating electrical machine according to claim 6, wherein the coercive force of the permanent magnet pieces on both outer sides in the circumferential direction of the frame is larger than the coercive force of the permanent magnet pieces on the inner side in the circumferential direction of the frame.   The rotor for an axial gap type rotating electrical machine according to claim 6, wherein the coercive force of the permanent magnet piece on the reverse side in the rotational direction of the frame is larger than the coercive force of the permanent magnet piece on the forward side in the rotational direction of the frame.   The rotor for an axial gap type rotating electrical machine according to any one of claims 1 to 5, wherein the permanent magnet pieces are arranged in a radial direction of the frame.   The rotor for an axial gap type rotating electrical machine according to claim 10, wherein the residual magnetic flux density of the permanent magnet piece on the outer peripheral side of the frame is larger than the residual magnetic flux density of the permanent magnet piece on the rotational axis side of the frame.   The rotor for an axial gap type rotating electrical machine according to claim 10, wherein the coercive force of the permanent magnet piece on the rotation axis side of the frame is larger than the coercive force of the permanent magnet piece on the outer peripheral side of the frame.   The rotor for an axial gap type rotating electrical machine according to any one of claims 1 to 12, wherein the permanent magnet piece is an Nd-Fe-B sintered magnet.

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