JP2010284035A - Permanent magnet rotating electrical machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet rotating electrical machine for increasing the torque/mass ratio, while suppressing torque pulsation. <P>SOLUTION: The rotating electrical machine includes a stator having armature windings; and a rotor which is rotatably supported with respect to the stator, and has an outside permanent magnet train and an inside permanent magnet train arranged in a Halbach array from a rotary shaft to a circumferential direction, and in which the armature windings are disposed between the outside permanent magnet train and the inside permanent magnet train in the circumferential direction, and the magnetic poles of outside permanent magnets and the magnetic poles of inside permanent magnets are directed in the same direction as to the direction of magnetic poles in the radial direction and directed in the reverse direction as to the direction of magnetic poles in the circumferential direction. The energy product of the cross section in the radial direction of the outside permanent magnet train is same as that of the cross section of the radial direction of the inside permanent magnet train, and the lengths of the outside permanent magnet train and the inside permanent magnet train are same in the rotary shaft direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a permanent magnet rotating electric machine having permanent magnets arranged in a Halbach array on a rotor rotatably supported by a stator having an electronic winding.

  A permanent magnet rotating electrical machine in which permanent magnets are arranged in Halbach is a main magnetic pole magnet in which N poles and S poles are alternately arranged in the radial direction, and magnetized in a direction other than the radial direction (for example, in the circumferential direction) The auxiliary magnet is provided (see, for example, Patent Documents 1 and 2). The main magnetic pole magnet and the auxiliary magnet of the permanent magnet rotating electrical machine in which the permanent magnets are arranged in the Halbach array are substantially cylindrical as a whole. When the permanent magnets are arranged in the Halbach array, the magnetic force in a specific direction can be increased. The rotating electrical machine having the permanent magnets arranged in the Halbach arrangement can achieve high output without increasing the size.

  In a conventional rotary electric machine having a permanent magnet array arranged in Halbach, an armature winding is wound around a yoke core, and a magnetic flux is formed between the permanent magnet, the armature winding, and the yoke core.

JP 2006-320109 A (FIG. 1) JP 2004-350427 A (FIGS. 1 and 2)

  However, since the rotating electrical machines described in Patent Document 1 and Patent Document 2 use iron cores for the stator and the rotor, torque pulsation increases. In addition, since the rotating electrical machines described in Patent Document 1 and Patent Document 2 use an iron core for the stator and the rotor, magnetic saturation of the iron core occurs, and even if a magnet that generates a strong magnetic field is used, torque can be reduced. There are limits to improvement.

  An object of the present invention is to provide a permanent magnet rotating electric machine that increases a torque mass ratio while suppressing torque pulsation.

  A permanent magnet rotating electric machine according to the present invention includes a stator having armature windings, an outer permanent magnet row and an inner permanent magnet row that are rotatably supported with respect to the stator and are arranged in a Halbach array in the circumferential direction from the rotating shaft. And the armature winding is disposed in the circumferential direction between the outer permanent magnet row and the inner permanent magnet row, and the magnetic pole direction of the outer permanent magnet and the magnetic pole direction of the inner permanent magnet However, the radial magnetic pole direction is the same direction, and the circumferential magnetic pole direction is the opposite direction of the rotor, and the energy product of the radial section of the outer permanent magnet row and the inner permanent magnet row The energy product of the radial cross section of the outer permanent magnet array is the same, and the outer permanent magnet array and the inner permanent magnet array have the same length in the rotational axis direction.

  ADVANTAGE OF THE INVENTION According to this invention, the permanent magnet rotary electric machine which enlarges a torque mass ratio can be provided, suppressing the pulsation of a torque.

FIG. 3 is a cross-sectional view in the direction of the rotation axis of the permanent magnet rotating electric machine according to the first embodiment of the present invention. The perspective view of the stator which concerns on the 1st Embodiment of this invention. The radial direction sectional view of the permanent magnet rotating electrical machine concerning a 1st embodiment of the present invention. The magnetic force line distribution figure which shows an example of the magnetic force line distribution of the permanent magnet rotary electric machine which concerns on the 1st Embodiment of this invention. The rotating shaft direction sectional drawing of the permanent magnet rotary electric machine which concerns on the 2nd Embodiment of this invention. The rotating shaft direction sectional drawing which shows the other example of the permanent magnet rotary electric machine which concerns on the 2nd Embodiment of this invention. The graph which shows the characteristic of the permanent magnet rotary electric machine which concerns on the 2nd Embodiment of this invention. The radial direction sectional view of the permanent magnet rotating electrical machine concerning a 3rd embodiment of the present invention. The graph which shows the torque pulsation rate in the permanent magnet rotary electric machine which concerns on the 3rd Embodiment of this invention. Radial direction sectional drawing which shows the other example of the permanent magnet rotary electric machine which concerns on the 3rd Embodiment of this invention. The rotating shaft direction sectional drawing of the permanent magnet rotary electric machine which concerns on the 4th Embodiment of this invention. The rotating shaft direction sectional drawing which shows the other example of the permanent magnet rotary electric machine which concerns on the 4th Embodiment of this invention.

  FIG. 1 is an axial cross-sectional view of a permanent magnet rotating electrical machine 1 according to the first embodiment. The permanent magnet rotating electrical machine 1 is configured such that an armature winding 4 and a shaft 7 are formed on a stator 6, and a permanent magnet row (outside) 2, a permanent magnet row (inside) 3 and a bearing 9 are formed on a rotor 5. Is done.

  Here, FIG. 2 is a perspective view of the stator 6 in which the armature winding 4 and the shaft 7 are formed. A shaft 7 is formed at the center of the stator 6. For example, when three-phase alternating current is used, the armature winding 4 is wound in the order of U phase-V phase-W phase. The armature winding 4 is formed of concentrated winding. The armature winding 4 is formed by a coil 42 in which a winding is wound around a bobbin 41. A plurality of armature windings 4 are arranged in the circumferential direction around a shaft 7 that is a rotating shaft. When the U-phase, V-phase, and W-phase are each constituted by a plurality of adjacent armature windings 4, the armature windings 4 that constitute each phase are connected by a coil connecting wire 8.

  A bearing 9 is disposed between the stator 6 and the rotor 5, and the rotor 5 is configured to rotate on the stator 6. The rotor 5 is provided with two substantially cylindrical permanent magnet rows (outer side) 2 and permanent magnet row (inner side) 3 configured in a Halbach array in the circumferential direction from the rotation axis.

  The rotor 5 has two rows of convex portions on the side facing the stator 6. The permanent magnet 16 of the permanent magnet row (outside) 2 is attached to the rotor 5 on the outer convex portion of the rotor 5 by, for example, adhesion. Furthermore, the permanent magnet 16 of the permanent magnet row | line | column (inner side) 3 is attached to the rotor 5 at the convex part inside the rotor 5. The rotor 5 is configured to dispose the armature winding 4 between the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3.

  FIG. 3 is a radial cross-sectional view of the permanent magnet rotating electrical machine 1 according to the first embodiment. In the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 attached to the rotor 5, the arrows shown in FIG. 3 indicate the magnetic pole directions. The armature winding 4 is wound in the circumferential direction in the order of U phase-V phase-W phase. The U-phase winding 10, the V-phase winding 11, and the W-phase winding 12 are each composed of two adjacent armature windings 4.

  In the permanent magnet row (outer side) 2, every other permanent magnet 16 magnetized in the radial direction is arranged along the circumferential direction so that the magnetic pole directions are alternately arranged in the radial direction. Further, the permanent magnet row (outside) 2 is arranged with every other permanent magnet 16 magnetized in the circumferential direction so that the magnetic pole directions are alternately arranged in the circumferential direction. That is, the permanent magnet row (outside) 2 has permanent magnets 16 magnetized in four different directions in the circumferential direction arranged at equal intervals. The permanent magnet row (inner side) 3 is the same as the arrangement order of the permanent magnets 16 in the permanent magnet row (outer side) 2. The permanent magnet 16 magnetized in the radial direction is configured such that the magnetic poles of the permanent magnet row (outer side) 2 and the magnetic poles of the permanent magnet row (inner side) 3 are in the same direction. Regarding the circumferentially magnetized permanent magnets 16 disposed between the radially magnetized permanent magnets 16, the magnetic poles of the permanent magnet row (outer side) 2 and the magnetic poles of the permanent magnet row (inner side) 3 Are configured in the opposite direction.

  Next, FIG. 4 is a magnetic force line distribution diagram showing an example of the magnetic force line distribution of the permanent magnet rotating electrical machine 1 according to the first embodiment. Magnetic fluxes of the permanent magnet row (outside) 2 and the permanent magnet row (inner side) 3 link the armature windings 4. The rotor 5 is rotated by passing, for example, a three-phase alternating current through the armature winding 4.

  As shown in FIG. 4, it can be seen that a large amount of magnetic flux is generated in the permanent magnet 16 magnetized in the radial direction. That is, the permanent magnet rotating electrical machine 1 can obtain a large torque by the magnetic flux interlinking with the armature winding 4. The magnetic fluxes of the permanent magnets 16 magnetized in the circumferential direction are opposite in the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 and function to cancel each other's magnetic flux.

  Next, the shapes of the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 constituting the permanent magnet rotating electrical machine 1 according to the first embodiment will be described. The permanent magnet 16 of the permanent magnet row (outer side) 2 and the permanent magnet 16 of the permanent magnet row (inner side) 3 that are opposed in the radial direction are the energy product and permanent of the radial section of the permanent magnet 16 of the permanent magnet row (outer side) 2. It arrange | positions so that the energy product of the radial direction cross section of the permanent magnet 16 of the magnet row | line | column (outside) 3 may become equal.

  If the material characteristics of the permanent magnet 16 constituting the permanent magnet row (outside) 2 and the permanent magnet 16 constituting the permanent magnet row (inside) 3 are the same, the permanent magnet row (outside) 2 is formed. The cross-sectional areas of the permanent magnet 16 and the permanent magnet 16 constituting the permanent magnet row (inner side) 3 are equal.

  Further, as shown in FIG. 1, the length (rotation) of the shaft 7 between the permanent magnet 16 in the permanent magnet row (outer side) 2 and the permanent magnet 16 in the permanent magnet row (inner side) 3 facing in the radial direction. The length in the rotation axis direction from the surface of the child 5 on which the permanent magnet 16 is joined is equal. If the material characteristics of the permanent magnet 16 constituting the permanent magnet row (outside) 2 and the permanent magnet 16 constituting the permanent magnet row (inside) 3 are the same, the permanent magnet row (outside) 2 is formed. The volumes of the permanent magnets 16 constituting the permanent magnet 16 and the permanent magnet row (inner side) 3 are equal.

  As described above, the permanent magnet 16 constituting the permanent magnet row (outer side) 2 and the permanent magnet 16 constituting the permanent magnet row (inner side) 3 in the radial direction have the same energy product in the radial cross section, and have a rotational axis. It arrange | positions so that the length of a direction may become equal.

  With this arrangement, the magnetomotive forces generated in the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 are equal. Therefore, the magnetic flux leaking to the outer side in the radial direction of the permanent magnet row (outer side) 2 and the magnetic flux leaking to the inner side in the radial direction of the permanent magnet row (inner side) 3 are reduced. The magnetic flux density between the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 becomes the maximum as compared with the case where the energy product in the radial cross section and the length in the rotation axis direction are made different. As a result, the torque generated by the permanent magnet rotating electrical machine 1 is also maximized.

  Next, a second embodiment will be described. FIG. 5 is a sectional view in the direction of the rotation axis of the permanent magnet rotating electrical machine 1 according to the second embodiment. FIG. 6 is a sectional view in the rotation axis direction showing another example of the permanent magnet rotating electrical machine 1 according to the second embodiment. The description of the same reference numerals as in the first embodiment is omitted. The second embodiment has the same shape as the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 described in the first embodiment.

  The permanent magnet rotating electrical machine 1 shown in FIGS. 5 and 6 includes a volume energy product of the permanent magnet 16 in the permanent magnet row (outer) 2 and a volume energy product of the permanent magnet 16 in the permanent magnet row (inner) 3 (permanent magnet). If the material characteristics of the permanent magnets 16 constituting the row (outside) 2 and the permanent magnet row (inside) 3 are the same, the volume is constant, and the inner diameter of the permanent magnet row (outside) 2 and the permanent magnet row (inside) 3 are constant. This is an example in which the outer diameter of each is fixed and the length in the rotation axis direction is changed. Here, a case will be described in which the permanent magnets 16 constituting the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 have the same volume.

  When the permanent magnet row (outside) 2 and the permanent magnet row (inner side) 3 are elongated in the rotation axis direction, the volume and the inner diameter of the permanent magnet row (outer side) 2 and the outer diameter of the permanent magnet row (inner side) 3 do not change. The outer diameter of the permanent magnet row (outer side) 2 is reduced, and the inner diameter of the permanent magnet row (inner side) 3 is increased.

  On the contrary, when the permanent magnet row (outside) 2 and the permanent magnet row (inside) 3 are shortened in the rotation axis direction, the volume and the inner diameter of the permanent magnet row (outside) 2 and the permanent magnet row (inside) 3 Since the outer diameter does not change, the outer diameter of the permanent magnet array (outer side) 2 is increased, and the inner diameter of the permanent magnet array (inner side) 3 is decreased.

  Here, as shown in FIG. 5 and FIG. 6, the outer diameter of the permanent magnet row (outer side) 2 is a, the length of the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 is b in the rotational axis direction. And FIG. 7 shows that the number of magnetic poles facing the radial direction in the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 constituting the permanent magnet rotating electrical machine 1 is constant, 6 is a graph obtained by measuring a ratio of mass to torque generated in the permanent magnet rotating electrical machine 1 (torque mass ratio) when the outer diameter of the accompanying permanent magnet row (outside) 2 is changed. The horizontal axis represents the ratio (%) of the length b in the rotation axis direction to the outer diameter a of the permanent magnet row (outer side) 2, and the vertical axis represents the ratio (%) to the maximum torque mass ratio.

  As shown in the graph of FIG. 5, when the lengths of the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 in the rotation axis direction are changed, there is a point where the torque mass ratio becomes maximum. If the length b in the rotation axis direction of the permanent magnet row (outside) 2 is in a range from 1/2 to 5 times the outer diameter a, the torque mass ratio of the permanent magnet rotating electrical machine 1 can be increased.

  When the length b in the rotation axis direction of the permanent magnet row (outside) 2 is smaller than ½ times the outer diameter a, the torque mass ratio of the permanent magnet rotating electrical machine 1 is rapidly reduced. When the length b in the rotation axis direction of the permanent magnet row (outer side) 2 becomes larger than 5 times the outer diameter a, the torque mass ratio of the permanent magnet rotating electrical machine 1 decreases.

  Therefore, by arranging the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 in the permanent magnet rotating electric machine 1 within a range that satisfies the above conditions, the permanent magnet rotating electric machine 1 can achieve high torque. Since the length b of the permanent magnet row (outer side) 2 in the direction of the rotation axis can be as wide as 1/2 to 5 times the outer diameter a, the permanent magnet rotating electrical machine 1 is longer in the direction of the rotation axis and in the radial direction. The shape can be changed according to the application, such as a very thin shape, a thin shape in the rotation axis direction and a thick shape in the radial direction.

  FIG. 8 is a radial cross-sectional view of the permanent magnet rotating electrical machine 1 according to the third embodiment. FIG. 10 is a radial cross-sectional view showing another example of the permanent magnet rotating electrical machine 1 according to the third embodiment. The description of the same reference numerals as in the first embodiment is omitted. The third embodiment is similar in shape to the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 described in the first embodiment or the second embodiment.

  As shown in FIG. 8, six armature windings 4 are arranged in the permanent magnet rotating electric machine 1. The permanent magnet rotating electrical machine 1 has a total of 3 sets of U-phase winding 10, V-phase winding 11 and W-phase winding 12 each consisting of two adjacent armature windings 4 as one set. Has been placed. The number of magnetic poles facing the radial direction of the permanent magnet array (outside) 2 and the permanent magnet array (inside) 3 is four.

  Here, FIG. 9 shows the number of magnetic poles in the radial direction of the permanent magnet row (outside) 2 and the permanent magnet row (inside) 3 and the total number of windings constituting the U phase, V phase, and W phase (number of slots). It is the graph which showed the result measured by changing. The horizontal axis represents the ratio of the length b in the rotation axis direction to the outer diameter a of the permanent magnet row (outer side) 2. The vertical axis represents the torque pulsation rate (%) in the permanent magnet rotating electrical machine 1.

  FIG. 9 shows the number of magnetic poles in the radial direction of the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 and the total number of sets (number of slots) of windings constituting the U phase, V phase, and W phase. As shown in FIG. 8, the ratio is 4: 3, and the ratio is 2: 3 as a comparative example. For example, 2P3S in the graph means that the number of magnetic poles in the radial direction is 2 and the number of slots is 2 slots. Assuming that the ratio of the number of magnetic poles in the radial direction to the number of slots is 2: 3, measurement is performed on 2P3S, 4P6S, 8P12S,..., 32P48S. Assuming that the ratio of the number of magnetic poles in the radial direction to the number of slots is 4: 3, measurement is performed on 4P3S, 8P6S, 12P9S,..., 32P24S.

  When the ratio of the number of magnetic poles in the radial direction to the number of slots is 2: 3 and the case of 4: 3, the ratio of the length b in the rotation axis direction to the outer diameter a of the permanent magnet array (outer) 2 is the same. It can be seen that the torque pulsation is smaller when the ratio of the number of magnetic poles in the radial direction and the number of slots is 4: 3 than when the ratio is 2: 3.

  Therefore, as shown in FIG. 8, when the ratio of the number of magnetic poles and the number of slots in the radial direction is 4: 3, the permanent magnet rotating electrical machine 1 has a different ratio (4P6S in the example of FIG. 9). Torque pulsation that occurs can be suppressed.

  The same applies to the example shown in FIG. The permanent magnet rotating electrical machine 1 is provided with 48 armature windings 4. The permanent magnet rotating electrical machine 1 includes eight sets of U-phase winding 10, V-phase winding 11, and W-phase winding 12 each composed of two adjacent armature windings 4 as a set, for a total of 24 sets. Has been placed. The number of magnetic poles in the radial direction of the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 is 32. The ratio of the number of magnetic poles in the radial direction to the number of slots is 4: 3. By configuring the permanent magnet rotating electrical machine 1 with the number of magnetic poles and the number of slots in such a radial direction, torque pulsation can be suppressed as compared with the case where the ratio is configured to be other ratio (32P48S in the example of FIG. 9). .

  FIG. 11 is a cross-sectional view in the rotation axis direction of the permanent magnet rotating electrical machine 1 according to the fourth embodiment. The description of the same reference numerals as in the first embodiment is omitted. The fourth embodiment is similar to the shapes of the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 described in the first to third embodiments.

  In the fourth embodiment, the armature winding 4 does not have the bobbin 41. The armature winding 4 is formed only by a coil 42 wound with a flat wire. Copper wire is used as the flat wire. Since the armature winding 4 is formed of a rectangular wire, the wire cross-sectional area becomes large. Therefore, heat generation by the armature winding 4 can be suppressed. Since the armature winding 4 is formed of a flat wire, it can be easily formed without the bobbin 41. Therefore, the armature winding 4 can improve the torque (electromotive force) to be generated by making maximum use of the space between the permanent magnet row (outer side) 2 and the permanent magnet row (inner side) 3 with the wire. it can. As described above, the permanent magnet rotating electrical machine 1 can generate a large torque and suppress the amount of heat generated by the armature winding 4.

  FIG. 12 is a sectional view in the rotation axis direction showing another example of the permanent magnet rotating electrical machine 1 according to the fourth embodiment. A printed circuit board 14 is arranged in the circumferential direction on the stator 6. The armature winding 4 is disposed on the printed board 14. As shown in FIG. 3, when the U-phase winding 10, the V-phase winding 11, and the W-phase winding 12 are each composed of two adjacent armature windings 4, depending on the connection pattern on the printed circuit board 14. The armature windings 4 are connected to each other. In the fourth embodiment, the connection pattern of the armature winding 4 is provided in advance on the printed circuit board 14, and the armature winding 4 is arranged on the printed circuit board 14, so that it is used in the first embodiment. The coil connecting wire 8 shown in FIG. 1 can be omitted.

  The coil connecting wire 8 must be disposed between the rotor 5 and the armature winding 4 in the rotation axis direction and above the armature winding 4. Therefore, in the permanent magnet rotating electrical machine 1 of the first embodiment, a space for passing the coil connecting wire 8 is required between the rotor 5 and the armature winding 4. By disposing the printed circuit board 14 on the permanent magnet rotating electric machine 1, the coil connecting wire 8 can be omitted, so that the permanent magnet rotating electric machine 1 can be reduced in size.

  According to the first to fourth embodiments, the permanent magnet rotating electrical machine 1 can be reduced in size, weight, and torque. It is more effective to appropriately combine the first to fourth embodiments.

DESCRIPTION OF SYMBOLS 1 ... Permanent magnet rotary electric machine, 2 ... Permanent magnet row | line | column (outside), 3 ... Permanent magnet row | line | column (inner side), 4 ... Armature winding, 5 ... Rotor, 6 ... Stator, 7 ... Shaft, 8 ... Coil crossing Wire, 9 ... bearing, 14 ... printed circuit board, 16 ... permanent magnet, 41 ... bobbin, 42 ... coil.

Claims (5)

A stator having armature windings;
The outer permanent magnet row and the inner permanent magnet row, which are rotatably supported with respect to the stator and are arranged in a Halbach array in the circumferential direction from the rotation axis, are arranged between the outer permanent magnet row and the inner permanent magnet row. The armature winding is arranged in the circumferential direction, and the direction of the magnetic pole of the outer permanent magnet and the direction of the magnetic pole of the inner permanent magnet are the same in the radial direction and the direction of the circumferential magnetic pole Is the rotor facing the opposite direction,
In a permanent magnet rotating electric machine having
The energy product of the radial cross section of the outer permanent magnet row and the energy product of the radial cross section of the inner permanent magnet row are the same, and the length of the outer permanent magnet row and the inner permanent magnet row in the rotational axis direction is the same. A permanent magnet rotating electrical machine characterized by the same.   2. The permanent magnet according to claim 1, wherein a length of the outer permanent magnet array and the inner permanent magnet array in the rotation axis direction is 1/2 to 5 times an outer diameter of the outer permanent magnet array. Rotating electric machine.   The ratio of the number of the magnetic poles in the radial direction in the outer permanent magnet row and the inner permanent magnet row to the number of phases constituted by the armature winding is 4: 3. The permanent magnet rotating electrical machine according to any one of 2.   4. The permanent magnet rotating electric machine according to claim 1, wherein the armature winding does not have a coil bobbin and is formed of a rectangular wire. 5.   The armature winding is arranged on a printed circuit board provided on the stator, and the armature windings are connected to each other by a pattern on the printed circuit board. The permanent magnet rotating electrical machine according to claim 1.

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