Magnetic field generating device and rotating electric machine

Abstract

A magnet holder provided in a magnet portion of an electric motor is formed of a non-magnetic material, and a plurality of spacers are arranged at a prescribed interval in a circumferential direction between an inner wall and an outer wall each formed in a cylindrical shape in the magnet holder. In the magnet holder, sockets into which permanent magnets are to be fitted are formed between the spacers, and a plurality of the sockets are formed in the circumferential direction. Thus, by fitting the permanent magnets into the sockets, respectively, the assembly of the permanent magnets, which are arranged with the direction of magnetization changed in sequence by an angle obtained by dividing one period of an electric angle by a division number n of any one of an integer of 3 or more, is facilitated.

Description

Technical Field

[0001] This invention relates to magnetic field generating devices and rotating electric machines. Background Technology

[0002] In electric motors, generators, and the like, magnets with alternating N and S poles of permanent magnets are used (NS array magnets). In a magnet, the magnetic field is used on one side (radially inside or outside) of the arranged permanent magnets. However, in an NS array magnet, the magnetic field is generated on both sides of the arranged permanent magnets, thus not effectively utilizing the magnetic field (the magnetic energy generated by the permanent magnets).

[0003] On the other hand, among magnets that arrange permanent magnets, there are, for example, Halbach array magnets in which multiple permanent magnets are arranged sequentially with their magnetic poles (magnetization directions) rotated by 90°. In this Halbach array magnet, one side of the arranged permanent magnets can generate a stronger magnetic field than the other side, thus effectively utilizing the magnetic field generated by the permanent magnets.

[0004] Japanese Patent Application Publication Nos. 2009-201343 and 2010-154688 disclose a magnet (double Helbeck array magnet) that utilizes the magnetic field generated by a permanent magnet more effectively by arranging two sets of Helbeck magnet arrays facing each other so that their magnetic fields reinforce each other. Summary of the Invention

[0005] The problem the invention aims to solve

[0006] However, in Hellbeck array magnets used in electric motors, numerous permanent magnets are arranged circumferentially, one after another (without gaps). Furthermore, the magnetization directions of adjacent permanent magnets are not 0° (magnetization directions are the same) or 180° (magnetization directions are opposite), but rather angles corresponding to the number of divisions (e.g., 90°, 72°, 45°, etc.). Therefore, in Hellbeck array magnets, strong repulsive or attractive forces are generated between adjacent permanent magnets in unexpected directions, requiring time and skill to assemble, thus improving operability is desirable.

[0007] The present invention was made in view of the above facts, and its object is to provide a magnetic field generating device and a rotary motor that can improve assembly operability.

[0008] Solution for solving the problem

[0009] A magnetic field generating device according to a first embodiment for achieving the above-mentioned objective includes: a magnet section, wherein a plurality of permanent magnets are arranged circumferentially, with any integer n (3 or more) as a division number, and the magnetization direction is sequentially changed by the division number n to obtain an angle obtained by dividing the electrical angle by one period; and a holding member, which is made of a non-magnetic material and has: an annular outer peripheral wall, wherein the outer peripheral surface of each of the permanent magnets abuts against the inner peripheral surface of the outer peripheral wall; and a plurality of partitions, which are respectively provided to protrude radially inward from the inner surface of the outer peripheral wall in the circumferential direction, and the permanent magnets are respectively embedded between adjacent partitions.

[0010] In the magnetic field generating device of the first type, any integer greater than 3 is used as the division number n. Multiple permanent magnets are arranged circumferentially by sequentially changing the magnetization direction according to the angle obtained by dividing one period of the electrical angle by the division number n, thereby forming a magnet section. Furthermore, a holding member made of a non-magnetic material such as a non-magnetic body or synthetic resin is provided in the magnet section, and the multiple permanent magnets are held in the magnet section by the holding member.

[0011] Here, the retaining member has multiple partitions, and the outer peripheral surface of each permanent magnet abuts against the inner peripheral surface of the annular outer peripheral wall. Each partition protrudes radially inward from the inner surface of the annular outer peripheral wall in the circumferential direction, and permanent magnets are embedded between adjacent partitions. Thus, the permanent magnets are held and assembled into the magnet section by the retaining member through their embedded arrangement between the circumferentially separated partitions, thereby improving the assemblability of the permanent magnets into the magnet section.

[0012] In the second type of magnetic field generating device, in the first type, the holding member includes an inner peripheral wall, the inner peripheral surface of each of the permanent magnets abuts against the outer peripheral surface of the inner peripheral wall, and the radially inner end of each of the partitions is connected to the outer peripheral surface of the inner peripheral wall.

[0013] In the second type of magnetic field generating device, an inner peripheral wall is provided in the holding member, and permanent magnets are respectively disposed between the inner peripheral wall and the outer peripheral wall. Therefore, it is easier to assemble the permanent magnets into the holding member, which can further improve the assemblability of the magnet part and increase the productivity of the magnet part.

[0014] In the third type of magnetic field generating device, in the first or second type, the thickness d of the partition is set based on the length lm of one side along the arrangement direction of the permanent magnet, which is a predetermined reference in the cross-section of the permanent magnet along the magnetization direction, and the number of divisions n. In this case, permanent magnets arranged in a straight line are applied to the permanent magnets, which serve as the reference for the length lm.

[0015] In the magnetic field generating device of the fourth mode, in the third mode, the thickness dimension d of the partition plate satisfies: 0 < d ≤ lm × 1 / (n + 1) × 1.5. In addition, in the magnetic field generating device of the fifth mode, in the third or fourth mode, the thickness dimension d of the partition plate satisfies: d = lm / (n + 1).

[0016] In the magnetic field generating device of the sixth mode, in any one of the first to fifth modes, it includes a ferromagnetic body, which is formed in an annular shape facing each of the permanent magnets of the magnet part, and is arranged to be relatively rotatable with respect to the magnet part, and a magnetic field is formed between the ferromagnetic body and the magnet part by the magnetic force of the magnet part.

[0017] In the magnetic field generating device of the sixth mode, the ferromagnetic body is arranged to be relatively rotatable with respect to the magnet part. Thereby, an effective magnetic field can be formed between the permanent magnet of the magnet part and the ferromagnetic body.

[0018] In the magnetic field generating device of the seventh mode, in any one of the first to fifth modes, the magnet part includes: a first magnet part, in which the plurality of permanent magnets are arranged in the circumferential direction; and a second magnet part, which is arranged on the radially outer side of the first magnet part, and in which the plurality of permanent magnets are arranged in the circumferential direction and can rotate integrally with the first magnet part. The holding member includes: a first holding member, which holds the plurality of permanent magnets of the first magnet part respectively; and a second holding member, which holds the plurality of permanent magnets of the second magnet part respectively.

[0019] In the magnetic field generating device of the seventh mode, the first magnet part and the second magnet part are provided in pairs, and the first magnet part and the second magnet part respectively have the first holding member and the second holding member. Thereby, when the first magnet part and the second magnet part are arranged in pairs, the assembly of the permanent magnets to the first magnet part and the second magnet part becomes easy, and the productivity can be improved.

[0020] The rotating electric machine of the eighth mode includes: a magnet part, using any integer of 3 or more as the division number n, arranging a plurality of permanent magnets in the circumferential direction by changing the magnetization direction in sequence at an angle obtained by dividing one cycle in electrical angle by the division number n; a holding member, which uses a non-magnetic material and has: an annular outer peripheral wall, the outer peripheral surface of each permanent magnet abuts against the inner peripheral surface of the outer peripheral wall; and a plurality of partition plates, which are respectively protruded from the inner surface of the outer peripheral wall in the circumferential direction of the outer peripheral wall toward the radial inner side, and the permanent magnets are respectively embedded between adjacent partition plates; and an armature, which is arranged to be relatively rotatable with respect to the magnet part in which each permanent magnet is held by the holding member.

[0021] In the eighth type of rotary motor, the magnet section and the armature rotate relative to each other. In the magnet section, any integer of 3 or higher is used as the division number n. Multiple permanent magnets are arranged circumferentially by changing the magnetization direction sequentially by the angle obtained by dividing the electrical angle by the division number n over one cycle. In addition, a holding member is provided in the magnet section to hold the multiple permanent magnets.

[0022] Here, a non-magnetic material is used for the retaining member. Furthermore, the retaining member has: an annular outer peripheral wall, with the outer peripheral surface of each permanent magnet abutting against the inner peripheral surface of the annular wall; and a plurality of partitions that protrude radially inward from the inner surface of the outer peripheral wall in the circumferential direction, with permanent magnets embedded between adjacent partitions. Thus, by embedding the permanent magnets between the circumferentially separated partitions of the outer peripheral wall, the permanent magnets can be assembled to the retaining member, facilitating the assembly of the permanent magnets to the magnet section and thus improving the assemblability of the magnet section.

[0023] The ninth type of rotary motor, in the eighth type, includes: a ferromagnetic body formed in an annular shape facing each of the permanent magnets of the magnet part, and configured to be rotatable relative to the magnet part, wherein three-phase coils of the armature are arranged circumferentially on the surface of the magnet part.

[0024] In the tenth embodiment of the rotary motor, in the eighth embodiment, the magnet section includes: a first magnet section having the plurality of permanent magnets arranged circumferentially; and a second magnet section disposed radially outside the first magnet section, having the plurality of permanent magnets arranged circumferentially, and capable of rotating integrally with the first magnet section; the retaining member includes: a first retaining member that retains the plurality of permanent magnets of the first magnet section; and a second retaining member that retains the plurality of permanent magnets of the second magnet section; and the armature having a three-phase coil arranged circumferentially between the first magnet section and the second magnet section.

[0025] In the eleventh type of rotary motor, in any one of the eighth to tenth types, the retaining member includes an inner peripheral wall, the inner peripheral surfaces of each of the permanent magnets abut against the outer peripheral surface of the inner peripheral wall, and the radially inner ends of each of the partitions are connected to the outer peripheral surface of the inner peripheral wall.

[0026] In any of the eighth to eleventh embodiments of the rotary motor, the thickness d of the partition is set based on the length lm of one side of the permanent magnet along the arrangement direction, which is a predetermined reference in the cross-section of the permanent magnet along the magnetization direction, and the number of divisions n. In this case, permanent magnets arranged in a straight line are applied to the permanent magnets, which serve as the reference for the length lm.

[0027] Here, in the twelfth mode of the rotating electric machine of this mode, regarding the circumferential length dimension Lf on the magnet part side of the ferromagnetic body and the number of magnetic poles P of the magnet part, the length dimension lm satisfies the relationship Lf = lm × n × P.

[0028] In addition, in the twelfth mode of the rotating electric machine of this mode, regarding the circumferential length dimension Lg of the center Gc of the gap between the first magnet part and the second magnet part and the number of magnetic poles P of the magnet part, the length dimension lm satisfies the relationship Lg = lm × n × P.

[0029] In the magnetic field generating device of the thirteenth mode in the twelfth embodiment, the thickness dimension d of the partition plate satisfies: 0 < d ≤ lm × 1 / (n + 1) × 1.5. In addition, in the magnetic field generating device of the fourteenth mode in the twelfth or thirteenth embodiment, the thickness dimension d of the partition plate satisfies: d = lm / (n + 1).

[0030] Advantages of the Invention

[0031] As described above, according to the magnetic field generating device and the rotating electric machine of the present invention, since in the magnet part in which a plurality of permanent magnets are arranged in the circumferential direction by changing the magnetization direction in sequence at angles obtained by dividing one electrical angle cycle by the division number n, where n is any integer of 3 or more, it is possible to easily assemble a plurality of permanent magnets, an effect of improving the productivity of the device can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram showing the main part of the motor according to this embodiment.

[0033] Figure 2 It is a schematic diagram showing a Halbach magnet array.

[0034] Figure 3A It is a schematic structural diagram showing a magnetic field generating part in which one Halbach magnet array is replaced with a ferromagnetic body in the magnetic field generating part where two Halbach magnet arrays face each other.

[0035] Figure 3B It is a schematic structural diagram showing a magnetic field generating part where two Halbach magnet arrays face each other.

[0036] Figure 4A It shows Figure 3A A schematic structural diagram of the deformed magnetic field generating part.

[0037] Figure 4B It shows Figure 3B A schematic structural diagram of the deformed magnetic field generating part.

[0038] Figure 5 This is a perspective view showing the magnet holder according to this embodiment.

[0039] Figure 6 This is a perspective view showing the main parts of the magnet section involved in this embodiment.

[0040] Figure 7A It is a graph showing the change in the volume ratio relative to the spacing size of the permanent magnet and the change in the amplitude of the fundamental wave when n=4.

[0041] Figure 7B It is a graph showing the change in the amplitude ratio of the fifth higher harmonic component to the fundamental component relative to the spacing size of the permanent magnet when n=4.

[0042] Figure 8A It is a graph showing the change in the volume ratio relative to the spacing size of the permanent magnet and the change in the amplitude of the fundamental wave when n=8.

[0043] Figure 8B It is a graph showing the change in the amplitude ratio of the fifth higher harmonic component to the fundamental component relative to the spacing size of the permanent magnet when n=8.

[0044] Figure 9 This is a schematic diagram showing the main parts of the electric motor involved in the variation example. Detailed Implementation

[0045] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0046] exist Figure 1 In the figure, a top view taken along the axis shows the general structure of the main part of the three-phase AC motor (hereinafter referred to as the motor) 10, which is a rotating electric motor according to an embodiment of the present invention.

[0047] like Figure 1 As shown, the electric motor 10 has a rotor 12 that is generally cylindrical in shape and serves as a rotating component, and a stator 14 that is generally annular (or possibly cylindrical) in shape and serves as a stationary component. In the electric motor 10, the central axis of the rotor 12 coincides with the central axis of the stator 14, and the rotor 12 is housed inside the stator 14 in a manner that allows for relative rotation.

[0048] A ring-shaped (or cylindrical) magnet portion 16 is provided on the outer periphery of the rotor 12. Furthermore, a ring-shaped (or cylindrical) outer cylinder portion 18, which serves as a ferromagnetic material, and an armature 20 are provided in the stator 14. The armature 20 is arranged circumferentially on the inner peripheral surface of the outer cylinder portion 18. Thus, in the motor 10, the armature 20 faces the radially outer side of the magnet portion 16 of the rotor 12, and the armature 20 can rotate relative to the magnet portion 16 as a single unit.

[0049] In the electric motor 10, a plurality of permanent magnets 22 are arranged circumferentially on the outer periphery of the magnet section 16. The magnetic field generating section 24, which serves as a magnetic field generating device, is composed of the magnet section 16 of the rotor 12 and the outer cylinder section 18 of the stator 14. The magnetic field generating section 24 forms a magnetic field between the magnet section 16 and the outer cylinder section 18.

[0050] The armature 20 of the motor 10 is provided with multiple coils, including a U-phase coil 20U, a V-phase coil 20V, and a W-phase coil 20W. Coils 20U, 20V, and 20W (coils 20U to 20W) are each wound with stranded wire. Furthermore, coils 20U to 20W are air-core coils, and are formed by being wound together.

[0051] In the armature 20, the three-phase coils 20U, 20V, and 20W are grouped together, and multiple groups of coils 20U to 20W are arranged in a predetermined order along the circumferential direction on the inner circumferential surface of the outer cylinder 18. In the motor 10, as an example, six groups of coils 20U to 20W are used, and the number of slots S of the motor 10 is set to 18. In the motor 10, the six groups of coils 20U to 20W are connected in series according to phase, for example, arranged in the circumferential direction of the outer cylinder 18 in the order of coils 20U, 20V, 20W, 20U, 20V, 20W, ... Alternatively, in the motor 10, coils 20U to 20W and coils 20U', 20V', and 20W' that are reverse-wound from coils 20U to 20W can also be used. In this case, in the motor 10, the coils are arranged circumferentially in the outer cylinder 18 in the order of coils 20U', 20U, 20U', 20V', 20V, 20V', 20W', 20W, 20W', 20U', 20U, ...

[0052] In the motor 10, three-phase (U-phase, V-phase, W-phase) alternating currents with a predetermined frequency, staggered by 120° from each other within one electrical angle cycle, are supplied to the coils 20U, 20V, and 20W respectively. As a result, in the motor 10, the rotor 12 rotates at a speed corresponding to the frequency of the three-phase alternating current supplied to the armature 20 (each of the multiple sets of coils 20U to 20W), and the output shaft 12A is driven to rotate integrally with the rotor 12.

[0053] Here, the magnet part 16 of the rotor 12, which forms the magnetic field generating part 24 in the electric motor 10, and the outer cylinder part 18 of the stator 14 will be described.

[0054] A Hellbeck magnet array is applied in the magnet section 16 of the magnetic field generating section 24. Figure 2The diagram shows a top view of a single Hellbeck array magnet (hereinafter referred to as a Hellbeck array magnet) 26 that incorporates a Hellbeck magnet array. Furthermore, in... Figure 3A and Figure 3B The top views show the general outlines of the magnetic field generating units 28A and 28B, which utilize the Hellbeck magnet array.

[0055] Furthermore, in the accompanying drawings, in the permanent magnet 22, the N-pole side is indicated by the symbol N, and the S-pole side is indicated by the symbol S. In the following description, the magnetization direction of the permanent magnet 22 is indicated by a solid arrow pointing from the S-pole side to the N-pole side, and magnetic field lines are indicated by dashed arrows pointing from the N-pole side to the S-pole side (within the permanent magnet 22, from the S-pole side to the N-pole side). Additionally, in the accompanying drawings, arrow x indicates one direction of the arrangement of the permanent magnets 22, and arrow y indicates the direction of the magnetic field lines that contribute to torque generation in the Hellbeck magnet array.

[0056] like Figure 2 As shown, in the Hellbeck magnet array, permanent magnets 22 with a roughly rectangular cross-section (roughly square, roughly cuboid in solid form) along the magnetization direction are used. Furthermore, in the Hellbeck magnet array, a division number n and an angle θ based on the division number n (illustration omitted) are set. The magnetization direction changes according to the predetermined angle θ, and n permanent magnets 22 corresponding to the division number n are arranged sequentially in a predetermined direction (arrow x direction). This forms a single Hellbeck array magnet 26 (hereinafter referred to as Hellbeck array magnet 26). Additionally, the angle θ is set as the angle between the magnetization directions of two adjacent permanent magnets 22 (illustration omitted).

[0057] In a Hellbeck magnet array, the division number n is an integer greater than or equal to 3, and the angle θ is the angle obtained by dividing one period of the electrical angle (2π = 360°) by the division number n (an integer greater than or equal to 3). In the Hellbeck array magnet 26, as an example, the division number n = 4 and the angle θ = 90° (θ = 360° / 4 = 90°).

[0058] In this Hellbeck array magnet 26, permanent magnets 22A, 22B, 22C, and 22D with magnetization directions changing at 90° are arranged sequentially (the arrangement of permanent magnets 22A to 22D is repeated). The magnetization directions of permanent magnets 22B and 22D on both sides of permanent magnet 22A are towards the side of permanent magnet 22A. As a result, in the Hellbeck array magnet 26, the magnetic field on the side intersecting the arrangement direction (the side with the magnetization direction of permanent magnet 22A) is enhanced, while the strength of the magnetic field on the other side (the side opposite to the magnetization direction of permanent magnet 22A) is suppressed.

[0059] like Figure 3BAs shown, the magnetic field generating unit 28B uses a double Helbeck array magnet with a pair of Helbeck array magnets 26 (26A, 26B). In the magnetic field generating unit 28B, the two sets of Helbeck array magnets 26A, 26B are separated by a predetermined interval (gap length 2G) and face each other.

[0060] Specifically, the magnetic field generating unit 28B is configured such that the stronger sides of the magnetic fields in the Halebeck array magnets 26A and 26B face each other. At this time, in the magnetic field generating unit 28B, the permanent magnet 22A of one of the Halebeck array magnets 26A and 26B (e.g., Halebeck array magnet 26A) faces the permanent magnet 22C of the other (e.g., Halebeck array magnet 26B) which has the same magnetization direction.

[0061] That is, the Hellbeck array magnets 26A and 26B are positioned such that the permanent magnets 22A (or 22C) are aligned with the same magnetization direction, and the permanent magnets 22B and 22D on either side of the permanent magnet 22A are interchanged in the Hellbeck array magnet 26B. Therefore, in the magnetic field generating unit 28B, a stronger magnetic field is formed between the paired Hellbeck array magnets 26A and 26B than when using a single Hellbeck array magnet 26.

[0062] On the other hand, the method of images (electrostatic method) is known in electric fields (electrostatic field). Although the illustration is omitted, in the method of images, the electric field lines between positive and negative point charges +q and -q, separated by a predetermined distance (interval dimension) 2g, are symmetrical about the plane of symmetry with respect to the midpoint between point charges +q and -q, i.e., the position at a distance g. In this state, if one of the point charges +q and -q (e.g., point charge -q) is replaced with a conductor (ideal conductor), and the face of the conductor on the side of point charge +q is positioned at a distance g (the midpoint between point charges +q and -q), then in the method of images, the electric field lines between point charge +q and the conductor, and the midpoint between point charges +q and -q (the position of the plane of symmetry) are the same as the electric field lines between point charges +q.

[0063] This mirror method works in a magnetic field by using a ferromagnetic material (ferromagnet) instead of a conductor. Therefore, as... Figure 3A As shown, in the magnetic field generating section 28A, a ferromagnetic body 30 made of ferromagnetic material is disposed, replacing the Hellbeck array magnet 26B in the magnetic field generating section 28B. The surface of the ferromagnetic body 30 on the Hellbeck array magnet 26A side is disposed at the gap center Gc, which is the middle position of the Hellbeck array magnets 26A and 26B in the magnetic field generating section 28B.

[0064] Therefore, in the magnetic field generating section 28A, the gap length G between the Hellbeck array magnet 26A and the ferromagnetic material 30 is relative to the gap length 2G, which is the spacing dimension between the Hellbeck array magnets 26A and 26B in the magnetic field generating section 28B. Thus, in the magnetic field generating section 28A, the magnetic flux distribution between the Hellbeck array magnet 26A and the ferromagnetic material 30 is the same as the magnetic flux distribution between the gap center Gc and the Hellbeck array magnet 26A in the magnetic field generating section 28A (double Hellbeck array magnet). In the electric motor 10 and the magnetic field generating section 24 according to this embodiment, the arrangement of the permanent magnets 22 in the magnetic field generating sections 28A and 28B is used as a reference.

[0065] On the other hand, in the dual Helbeck magnet array, by deforming each permanent magnet 22 in a manner that satisfies specified conditions, the magnetic field generating parts 28A and 28B are formed into a ring shape, thereby achieving the same effect as that produced by the dual Helbeck magnet array.

[0066] like Figure 1 As shown, in the magnetic field generating section 24 of the electric motor 10, k sets (number of sets k) of permanent magnets 22A to 22D are used, and a Heilbeck magnet array in which permanent magnets 22A to 22D are arranged in circumferentially forms the magnet section 16. In the electric motor 10, as an example, the magnet section 16 uses permanent magnets 22A to 22D with a number of sets k of 8 (8 sets, k = 8).

[0067] exist Figure 4A and Figure 4B In the diagram, a top view taken along the axial direction shows the magnetic field generating section (magnet) where permanent magnets 22 are arranged in a ring. Additionally, in... Figure 4A The diagram shows a magnetic field generator 32A corresponding to a magnetic field generator 28A that uses a set of Heilbeck magnet arrays. Figure 4B The diagram shows the magnetic field generating section 32B, which corresponds to the magnetic field generating section 28B that uses two sets of Hellbeck magnet arrays (double Hellbeck magnet array). Furthermore, for the sake of simplicity, the deformed permanent magnet is labeled with the same markings as the original permanent magnet 22.

[0068] In the Hellbeck magnet array, n permanent magnets 22 corresponding to the division number n are grouped together. In the Hellbeck magnet array, the arrangement of the n permanent magnets 22 corresponds to the two poles of N pole / S pole, and the number of magnetic poles P is equivalent to two poles. Therefore, in the magnet section 16 of the motor 10, the total number M of the number of permanent magnets 22 in one revolution consisting of 8 groups of permanent magnets 22A to 22D is 32 (M = n × k = 32) permanent magnets 22, and the number of magnetic poles P in the motor 10 is 16 poles.

[0069] like Figure 2 , Figure 3A and Figure 3B As shown, the pole pitch τ in the Hellbeck array magnets 26 (26A, 26B) is set as the length along the arrangement direction of the range of magnetization direction reversal (range of 180°). With the permanent magnets 22 arranged in close contact, the pole pitch τ is τ = (n × lm) / 2, based on the number of divisions n and the length (length dimension) lm of one side of the permanent magnet 22 along the arrangement direction. In the magnetic field generating section 28B, the gap length 2G, which yields the maximum number of magnetic flux turns at the gap center Gc, is set to a range of 0.5 to 2.0 times the pole pitch τ (0.5τ ≤ 2G ≤ 2.0τ). Furthermore, the length dimension lm of the permanent magnet 22 is a pre-set reference length dimension, applicable to the length of the armature 20 side of the permanent magnet 22 in the Hellbeck array magnets 26 (26A, 26B) that generates the magnetic field.

[0070] Therefore, in the magnetic field generating section 28A, the gap length G, which serves as the distance between the outer peripheral surface of the Helbeck array magnet 26A (the outer peripheral surface of the permanent magnet 22) and the surface of the ferromagnetic body 30, is set to be in the range of 0.25 to 1.0 times the pole pitch τ (0.25τ≤G≤1.0τ). Furthermore, the gap length G relative to the number of divisions n is within the range of (0.25×n×lm×1 / 2) to (1.0×n×lm×1 / 2) times the length dimension lm of the permanent magnet 22 (i.e., (0.125×n×lm)≤G≤(0.5×n×lm)). Thus, when the number of divisions n=4, the gap length G is within the range of 0.5 to 2.0 times the length dimension lm of the permanent magnet 22 ((0.5×lm)≤G≤(2.0×lm)).

[0071] When the Hellbeck array magnets 26A and 26B in the magnetic field generating section 28B are arranged with k groups of permanent magnets 22 with a division number of n, the length dimension of the gap center Gc along the arrangement direction is k×n×lm=2×k×τ.

[0072] exist Figure 4B In the magnetic field generating unit 32B shown, the Hellbeck array magnets 26A and 26B in the magnetic field generating unit 28B are deformed in a manner that meets specified conditions, thereby forming Hellbeck array magnets 34A and 34B. In the magnetic field generating unit 32B, the gap center Gc is used as a reference circle, and the Hellbeck array magnets 34A and 34B are arranged with the gap center Gc between them. In the magnetic field generating unit 32B, the Hellbeck array magnets 34A and 34B face each other with the gap 36 between them. Furthermore, the Hellbeck array magnets 34A and 34B are formed as follows: the permanent magnets 22 in the Hellbeck array magnets 26A and 26B are used as references, and the permanent magnets 22 are deformed into fan-shaped rings (partial rings) and arranged in the circumferential direction.

[0073] Here, the length (circumference) of the gap center Gc of the magnetic field generating unit 32B and the magnetic field generating unit 28B is the same. In addition, in the magnetic field generating unit 32B, the interval (gap length) between the Hellbeck array magnets 34A and 34B is set to be the same as the gap length 2G in the magnetic field generating unit 28B, and the interval between each of the Hellbeck array magnets 34A and 34B and the gap center Gc is set to the gap length G.

[0074] Furthermore, in the magnetic field generating unit 32B, regarding the cross-sectional area of ​​the radial section, the ratio of the cross-sectional area between the gap center Gc in the gap 36 and the Hellbeck array magnet 34A to the cross-sectional area between the gap center Gc and the Hellbeck array magnet 34B is set to be the same as the ratio of the cross-sectional area of ​​the Hellbeck array magnet 34A to the cross-sectional area of ​​the Hellbeck array magnet 34B.

[0075] That is, in the radial cross-section of the magnetic field generating unit 32B, the cross-sectional area between the gap center Gc and the Hellbeck array magnet 34B is designated as area S1, the cross-sectional area between the gap center Gc and the Hellbeck array magnet 34A is designated as area S2, the cross-sectional area of ​​the Hellbeck array magnet 34B is designated as area S3, and the cross-sectional area of ​​the Hellbeck array magnet 34A is designated as area S4. In the magnetic field generating unit 32B, the relationship S2:S1=S4:S3 is satisfied (S1 / S2=S3 / S4).

[0076] Furthermore, in the magnetic field generating unit 32B, regarding the specified angle... The range (for example, the range of a group of permanent magnets 22A to 22D, in) Figure 4B Within the radial cross-section (represented by the double-dotted line), the cross-sectional area between the gap center Gc and the Hellbeck array magnet 34B is defined as area Sgo, the cross-sectional area between the gap center Gc and the Hellbeck array magnet 34A is defined as area Sgi, the cross-sectional area of ​​the Hellbeck array magnet 34B is defined as area Smo, and the cross-sectional area of ​​the Hellbeck array magnet 34A is defined as Smi. In the magnetic field generating unit 32B, the relationship Sgi:Sgo = Smi:Smo is satisfied (Smi / Smo = Sgi / Sgo. Furthermore, Smo / Smi = Sgo / Sgi is also satisfied).

[0077] In the magnetic field generating section 32B formed in this way, the inner diameter of the Hellbeck array magnet 34A, the outer diameter of the Hellbeck array magnet 34A (the inner diameter of the gap 36), the radius of the gap center Gc, the inner diameter of the Hellbeck array magnet 34B (the outer diameter of the gap 36), and the outer diameter of the Hellbeck array magnet 34B are respectively set as Rh, Ri, Rco, Rg, and Ro. In this case, the relationships Ri = (Rco - G) and Rg = (Rco + G) are obtained.

[0078] At this point, the areas Sgo, Sgi, Smo, and Smi are represented by the following formulas.

[0079] Sgo=(Rg 2 -Rco 2 )×π×φ / 360

[0080] Sgi=(Rco 2 -Ri2)×π×φ / 360

[0081] Smo = (Ro 2 -Rg 2 )×π×φ / 360

[0082] Smi=(Ri 2 -Rh 2 )×π×φ / 360

[0083] Furthermore, in the Hellbeck array magnets 34A and 34B, the permanent magnets 22, which are identical to those in the Hellbeck array magnets 26A and 26B, are formed with a fan-shaped ring (partial ring) with a cross-section approximately rectangular (or square) along the magnetization direction. In the magnetic field generating section 32B, the reference permanent magnets 22 are deformed and arranged in a manner that satisfies these conditions, thereby achieving the same effect produced by the Hellbeck magnet array as in the magnetic field generating section 28B.

[0084] According to the above-described method of modification, the length dimension lm of the permanent magnet 22 along the arrangement direction is expressed as follows, depending on the type (combination) of the magnet (magnet part 16) and the armature (armature 20).

[0085] In the magnetic field generating unit 28B employing a dual Hellbeck magnet array, when the permanent magnets 22 are in close contact with each other, the length of the gap center Gc corresponding to a set of permanent magnets 22 is 2×τ=n×lm. Furthermore, in the magnetic field generating units 28A and 28B, the length lm of the permanent magnet 22 is expressed as lm=2×τ×1 / n (τ=n×lm / 2). At this time, the length lm of the permanent magnet 22 is the same as the length of the permanent magnet 22 (the permanent magnet 22 before deformation) in the Hellbeck array magnets 26A and 26B.

[0086] On the other hand, in the magnetic field generating unit 32B that uses a dual Hellbeck magnet array, the range (angle) of a set of permanent magnets 22 The circumferential length Lc of the gap center Gc within the range is Here, when the pole distance at the gap center Gc is set to τ, Lc = 2 × τ. When the length of the permanent magnet 22 at the gap center Gc along the arrangement direction is set to the length dimension lm, Lc = n × lm. Therefore, in the magnetic field generating unit 32B, the length dimension lm at the gap center Gc corresponds to Lc / n. Furthermore, when the length dimension of the entire circumference of the gap center Gc in the magnetic field generating unit 32B is set to Lg, the length dimension Lg, the number of magnetic poles P, the number of divisions n, and the length dimension lm satisfy the relationship Lg = lm × n × P.

[0087] Furthermore, in the Hellbeck array magnet 34B of the magnetic field generating unit 32B, the circumferential length Lo of the surface on the side of the gap 36 is... In the Hellbeck array magnet 34B, when the pole distance of the face on the gap 36 side is set to τ, Lo = 2 × τ. With the permanent magnets 22 in close contact with each other, when the length of the permanent magnets 22 on the gap 36 side (magnetic field side) of the Hellbeck array magnet 34B along the arrangement direction (circumferential direction) is set to lm', Lo = n × lm'. Therefore, the corresponding length of the permanent magnets 22 on the gap 36 side of the Hellbeck array magnet 34B is lm' = Lo / n.

[0088] Furthermore, in the Hellbeck array magnet 34A of the magnetic field generating unit 32B, the circumferential length dimension Li of the surface on the gap 36 side (magnetic field side) is... In the Hellbeck array magnet 34A, when the pole pitch in the face on the gap 36 side is set to τ, Li = 2 × τ. With the permanent magnets 22 in close contact with each other, when the length of the permanent magnets 22 on the gap 36 side of the Hellbeck array magnet 34A along the arrangement direction is lm”, Li = n × lm”. Therefore, the corresponding length of the permanent magnets 22 on the gap 36 side of the Hellbeck array magnet 34A, lm” = Li / n.

[0089] Here, in Figure 4A In the magnetic field generating section 32A shown, the Hellbeck array magnet 34B in the magnetic field generating section 32B is replaced with a ferromagnetic material 30A. The ferromagnetic material 30A is formed into a ring shape with an inner diameter equal to the radius of the gap center Gc, and the inner circumference (inner circumferential surface) of the ferromagnetic material 30A is set at the position of the gap center Gc. Thus, the magnetic field generating section 32A is the same as the case where the magnetic field generating section 28A is transformed into a ring shape, and the magnetic field generating section 32A has the same effect as the magnetic field generating section 28A generated by a double Hellbeck magnet array.

[0090] Furthermore, in the Hellbeck array magnet 34A of the magnetic field generating unit 32A, the circumferential length dimension of the surface on the gap 36 side of the ferromagnetic body 30A is the same as the length dimension Lc. Therefore, in the magnetic field generating unit 32A, when the full circumference length dimension of the gap 36 side of the ferromagnetic body 30A is set as Lf, the length dimension Lf, the number of magnetic poles P, the number of divisions n, and the length dimension lm satisfy the relationship Lf = lm × n × P.

[0091] Furthermore, in the magnetic field generating unit 32A, the circumferential length of the surface on the gap 36 side of the Hellbeck array magnet 34A is Li = 2 × τ. When the permanent magnets 22 are close to each other, the length of the permanent magnets 22 on the gap 36 side of the Hellbeck array magnet 34A along the arrangement direction is lm” = Li / n. Furthermore, the pole pitch τ is set to the range of magnetization direction reversal in a group of permanent magnets 22 (22A~22D) (a range of 180° change). Therefore, when there is a gap between the permanent magnets 22, the pole pitch τ can also be said to include the range of that gap.

[0092] Furthermore, in the magnetic field generating section 32A, the gap length G satisfies the range of 0.25 times to 1.0 times the pole pitch τ (0.25τ≤G≤1.0τ), and the gap length G relative to the number of divisions n has a relationship of (0.125×n×lm) times to (0.5×n×lm) times the length dimension lm of the permanent magnet 22 along the arrangement direction ((0.125×n×lm)≤G≤(0.5×n×lm)).

[0093] like Figure 1 As shown, the same structure as the magnetic field generating section 32A is used in the magnetic field generating section 24 of the electric motor 10. In the magnet section 16 of the magnetic field generating section 24, a Hellbeck array magnet 34A in which permanent magnets 22 are arranged in a ring is used, and a ferromagnetic material is used for the outer cylinder section 18 of the stator 14 surrounding the magnet section 16 (the outer cylinder section 18 corresponds to the ferromagnetic material 30). Thus, in the electric motor 10, the magnetic flux distribution between the magnet section 16 and the outer cylinder section 18 is the same as the magnetic flux distribution between the Hellbeck array magnet 34A and the gap center Gc in the magnetic field generating section 32B.

[0094] In this magnetic field generating section 24, any size can be applied to the thickness dimension ly of the outer cylinder section 18 along the radial direction. By reducing the thickness dimension ly of the outer cylinder section 18, it is possible to suppress the increase in the outer diameter of the motor 10, thereby increasing the output density of the motor 10. At this time, in the motor 10, torque fluctuations are prone to occur due to magnetic saturation generated by the outer cylinder section 18. However, by applying the Halebeck array magnet 26A in the magnet section 16, the effect of generating a Halebeck magnet array that can suppress torque fluctuations is obtained.

[0095] Furthermore, by increasing the thickness dimension ly of the outer cylinder 18, although it is difficult to suppress the increase in the outer diameter of the motor 10, it is possible to suppress magnetic saturation of the outer cylinder 18 and effectively suppress torque fluctuations.

[0096] Therefore, the thickness dimension ly of the outer cylinder 18 is preferably the maximum dimension at which magnetic saturation occurs (or the minimum dimension at which magnetic saturation does not occur). This prevents the outer diameter of the motor 10 from increasing, thereby increasing the output density and effectively suppressing torque fluctuations.

[0097] However, a magnet retainer 40, serving as a retaining member, is provided in the rotor 12 of the electric motor 10. Figure 5 The schematic structure of the magnet holder 40 is shown in a three-dimensional diagram. Figure 6 The main part of the magnet section 16 is shown in a three-dimensional diagram.

[0098] The magnet holder 40 is made of a non-magnetic material. This non-magnetic material can be paramagnetic, diamagnetic, or various resin materials (synthetic resins). Aluminum, various transition metals, and various synthetic resins can be used for the magnet holder 40. In this embodiment, from the viewpoint of achieving both high strength and toughness while also being lightweight, carbon fiber reinforced plastic (CFRP) is used for the magnet holder 40.

[0099] like Figure 5 As shown, the magnet holder 40 has an inner wall 42, which is formed as an inner peripheral wall, and an outer wall 44, which is formed as an outer peripheral wall and is approximately cylindrical in shape with a predetermined thickness. In the magnet holder 40, the outer diameter of the inner wall 42 is smaller than the inner diameter of the outer wall 44. In the magnet holder 40, the central axis of the inner wall 42 coincides with the central axis of the outer wall 44, and the inner wall 42 is coaxially disposed within the outer wall 44. Furthermore, in this embodiment, the axial dimension of the magnet holder 40 is set to be the same as the dimension of the permanent magnet 22 in the direction intersecting the magnetization direction.

[0100] Furthermore, in the magnet holder 40, the distance between the outer peripheral surface of the inner wall 42 and the inner peripheral surface of the outer wall 44 is the same as the radial dimension of the deformed permanent magnet 22. Thus, the magnet holder 40 is generally cylindrical in shape, the inner peripheral surface of the inner wall 42 is fixed (bonded) to the output shaft 12A of the rotor 12, and the magnet holder 40 is arranged on the rotor 12 in a manner that allows it to rotate integrally.

[0101] like Figure 1 , Figure 5 ,as well as Figure 6As shown, in the magnet holder 40, a plurality of spacers 46 serving as partitions are provided between the inner wall 42 and the outer wall 44. The magnet holder 40 is integrally formed of the inner wall 42, the outer wall 44, and the spacers 46 by resin molding. The spacers 46 are arranged at predetermined intervals along the radial direction of the magnet holder 40.

[0102] In the magnet holder 40, spacers are respectively disposed between adjacent permanent magnets 22, and the spacing between each spacer 46 is approximately the same as the circumferential length of the permanent magnet 22. For example, the circumferential spacing dimension on the outer wall 44 side of each spacer 46 is the same as the circumferential dimension of the outer peripheral surface of the permanent magnet 22 in the magnet section 16. Furthermore, the circumferential spacing dimension on the inner wall 42 side of each spacer 46 is the same as the circumferential length dimension of the inner peripheral surface of the permanent magnet 22 in the magnet section 16.

[0103] Therefore, 32 (k×n) spacers 46 are formed in the magnet holder 40, and between adjacent spacers 46, insertion slots 48 for embedding permanent magnets 22 are formed, corresponding to the number of permanent magnets 22. Each insertion slot 48 is configured such that the shape of its opening cross-section in the direction intersecting the axial direction of the magnet holder 40 (radial direction) is the same as the cross-sectional shape of the permanent magnet 22 along the magnetization direction.

[0104] In the rotor 12 of the motor 10, permanent magnets 22 are embedded in each socket 48 of the magnet holder 40. The peripheral surfaces of the embedded permanent magnets are joined to the outer peripheral surface of the inner wall 42, the inner peripheral surface of the outer wall 44, and the inner surface of each spacer 46 (the inner surface of the socket 48) of the magnet holder 40 by means of bonding or the like.

[0105] On the other hand, in the Heilbeck magnet array, the spacing of the permanent magnets 22 affects the magnetic field. In the magnetic field generating section 24, the circumferential dimension, i.e., the thickness dimension d, of the spacers 46 in the magnet holder 40 affects the magnetic field formed by the magnet section 16.

[0106] Here, in the magnet holder 40, the thickness d (mm) of the spacer 46 is set according to the length lm (mm) of the permanent magnet 22 along the arrangement direction and the number of divisions n. The thickness d of the spacer 46 of the magnet holder 40 is set according to the length lm (mm) of the permanent magnet 22 along the arrangement direction and the number of divisions n, and in a manner that satisfies formula (1).

[0107] 0 < d ≤ Im × 1 / (n + 1) × 1.5

[0108] ···(1)

[0109] Additionally, lm×1 / (n+1)×1.5=1m×1.5 / (n+1). Furthermore, in the magnet holder 40 formed of non-magnetic material, the outer wall 44 of the magnetic field generating part 24, which becomes the outer side of the permanent magnet 22, is included in area S2, and the spacer 46 between the permanent magnets 22 is included in area S4.

[0110] In the electric motor 10 configured in this way, a magnetic field generating section 24 is formed by the magnet section 16 of the rotor 12 and the outer cylinder section 18 of the stator 14, and an armature 20 (coils 20U to 20W) is disposed in the magnetic field generating section 24. Therefore, in the electric motor 10, by supplying three-phase alternating current of a specified voltage to the coils 20U to 20W respectively, the rotor 12 rotates, and the output shaft 12A is driven to rotate. Furthermore, the output shaft 12A of the electric motor 10 is driven to rotate at a speed corresponding to the frequency of the three-phase alternating current supplied to the coils 20U to 20W respectively.

[0111] In the magnetic field generating section 24 of the electric motor 10, the magnet section 16 is surrounded by the outer cylinder section 18, and the outer cylinder section 18 faces each of the permanent magnets 22 of the magnet section 16. In the magnet section 16, a Hellbeck array magnet 34A is formed by a plurality of permanent magnets 22. Furthermore, in the magnetic field generating section 24, the outer cylinder section 18 is positioned relative to the magnet section 16 at a position corresponding to the gap center Gc of the Hellbeck array magnets 34A and 34B in the double Hellbeck magnet array, and the outer cylinder section 18 is made of a ferromagnetic material. As a result, in the magnetic field generating section 24, the same magnetic field (approximate magnetic field) as when the double Hellbeck magnet array is applied is formed between the magnet section 16 and the outer cylinder section 18.

[0112] Therefore, appropriately reproducing the effect of a dual Hellbeck magnet array in the electric motor 10 can suppress torque ripples. Thus, in the electric motor 10, using a single Hellbeck array magnet 34A can achieve the same effect as using a dual Hellbeck array magnet 34A and 34B, thereby suppressing the generation of torque ripples in the electric motor 10.

[0113] Furthermore, in the motor 10, an outer cylinder portion 18 is fixedly arranged radially outward of the magnet portion 16, thus enabling the outer cylinder portion 18 to function as a housing. As a result, the motor 10 can be miniaturized and the number of parts reduced, achieving cost reduction and increasing output density. Moreover, since a Hellbeck magnet array is used in the motor 10, the number of permanent magnets 22 can be reduced compared to the case of using a dual Hellbeck magnet array, further achieving weight reduction and cost reduction, and effectively increasing output density.

[0114] Generally, among motors with similar radial cross-sectional shapes and the same axial length, the output (rotational angular velocity × torque) can be increased proportionally to the cube of a similar ratio. In motor 10, the radial size is more generous than in the case of using a dual Hellbeck array magnet, thus there is a possibility of increasing the output. Therefore, in motor 10, a larger output density (output / volume ratio) can be expected compared to the case of using a dual Hellbeck array magnet.

[0115] Furthermore, in the motor 10, coils 20U to 20W are air-core coils, and stranded wire is used for coils 20U to 20W. By making coils 20U to 20W air-core coils in the motor 10, the generation of back electromotive force is suppressed, thereby suppressing the heating of switching elements in the inverter circuit during inverter control. Furthermore, by using stranded wire for the winding of coils 20U to 20W, inductance is reduced, effectively suppressing heating and the back electromotive force generated in each coil 20U to 20W. Therefore, the rated speed of the motor 10 can be increased, achieving high rotational speed.

[0116] Furthermore, in the electric motor 10, since the outer cylinder 18, in which the armature 20 (coils 20U to 20W) is mounted, does not rotate, cooling units such as cooling plates and cooling pipes can be used to cool the outer cylinder 18, and the armature 20 inside the outer cylinder 18 can also be cooled together with the outer cylinder 18. As a result, the electric motor 10 can effectively suppress heat generation and can output a large torque in a short time.

[0117] Next, the assembly of the permanent magnet 22 in the magnet section 16 of the magnetic field generating section 24 will be described.

[0118] In the magnet section 16 of the magnetic field generating section 24, a plurality of permanent magnets 22 are arranged in the circumferential direction, and the magnetization direction of adjacent permanent magnets 22 is changed by an angle θ.

[0119] Here, a magnet holder 40 is used in the magnet section 16 of the magnetic field generating section 24. Multiple spacers 46 are provided between the inner wall 42 and the outer wall 44 of the magnet holder 40, forming multiple slots 48 for embedding permanent magnets 22. The number of slots 48 corresponds to the number of permanent magnets 22 used in the magnet section 16, and the slots 48 are arranged circumferentially on the magnet holder 40. Therefore, multiple permanent magnets 22 are sequentially embedded into the slots 48 of the magnet holder 40 by changing their magnetization direction at a predetermined angle θ, thereby assembling them in the magnet section 16.

[0120] On the other hand, attractive and repulsive forces act between adjacent permanent magnets 22. Furthermore, the magnetization directions of the permanent magnets 22 are offset by a predetermined angle θ, and adjacent permanent magnets 22 are extremely close. Therefore, when the permanent magnets 22 are arranged sequentially in the circumferential direction, large attractive and repulsive forces sometimes act between adjacent permanent magnets 22 in the direction that causes the permanent magnets 22 to rotate.

[0121] The permanent magnets 22 used in the magnet section 16 have identical cross-sectional shapes along the magnetization direction, and a number of slots 48 corresponding to the number of permanent magnets 22 are formed in the magnet holder 40. Therefore, in the magnet holder 40, the magnetization direction of the permanent magnets 22 inserted into one slot 48 is determined, thereby determining the magnetization direction of all permanent magnets 22 inserted into all slots 48. Furthermore, in each slot 48, the movement of the permanent magnet 22 is restricted by the inner wall 42, the outer wall 44, and the spacer 46. Consequently, the attractive and repulsive forces acting between the permanent magnets 22 weaken as the distance between them increases.

[0122] Thus, in the magnet holder 40, the permanent magnet 22 is inserted into the socket 48 by leaving one or more (one or a predetermined number) gaps, thereby facilitating the assembly of the permanent magnet 22. For example, as Figure 6 As shown, in the magnet holder 40, permanent magnets 22A, 22C, ... are inserted into their corresponding slots 48 in the order of 22A, 22C, ... and then permanent magnets 22B, 22D, ... are inserted into the empty slots 48 between permanent magnets 22A, 22C, ... . Thus, even if there are strong attractive or repulsive forces between the permanent magnets 22, multiple permanent magnets 22 can be easily assembled in a circumferential arrangement.

[0123] Furthermore, the magnet holder 40 utilizes the inner wall 42, outer wall 44, and spacer 46 to restrict the movement of the permanent magnet 22 embedded in the socket 48. Therefore, the magnet holder 40 can prevent the permanent magnet 22 already embedded in the socket 48 from moving due to the magnetic force of a newly embedded permanent magnet 22. Thus, the magnet holder 40 effectively assists in the assembly of the permanent magnet 22.

[0124] Therefore, even when the multiple permanent magnets 22 are arranged close to each other, the magnet holder 40 can easily assemble the multiple permanent magnets 22 individually, and can easily assemble the magnet section 16 in which the multiple permanent magnets 22 are arranged in the circumferential direction.

[0125] Furthermore, a carbon fiber reinforced plastic (CFRP) is used for the magnet holder 40. Therefore, when assembling the permanent magnets 22, even if attractive and repulsive forces act between the adjacent permanent magnets 22, the magnet holder 40 will not deform (skew of the socket 48) on the inner wall 42, outer wall 44, and spacer 46. Thus, the magnet holder 40 can hold the multiple permanent magnets 22 in fixed positions.

[0126] In addition, the permanent magnet 22 inserted into the socket 48 of the magnet holder 40 is fixed by bonding to the inner peripheral surface (each surface of the inner wall 42, outer wall 44, and spacer 46) of the socket 48 of the magnet holder 40. Thus, the permanent magnet 22 is reliably fixed to the rotor 12 by the magnet holder 40.

[0127] In addition, in the motor 10, as the rotor 12 rotates, a centrifugal force acts on the permanent magnets 22 in the magnet portion 16. Therefore, by increasing the rotational speed of the motor 10, the centrifugal force acting on the permanent magnets 22 increases. At this time, an outer wall 44 is formed on the radially outer side of the magnet holder 40, and in the magnet holder 40, the outer wall 44 is connected to the inner wall 42 by a plurality of spacers 46. Thus, in the magnet holder 40, even if a large centrifugal force acts on the permanent magnets 22 due to the rotation of the rotor 12, the movement of the outer wall 44 to the radially outer side of the permanent magnets 22 can be effectively restricted, and the permanent magnets 22 can be properly held. Thus, in the motor 10, by providing the magnet holder 40, stable high-speed rotation can be performed. Moreover, since a carbon fiber reinforced plastic with high strength and toughness is used for the magnet holder 40, the deviation of the permanent magnets 22 due to the centrifugal force can be reliably restricted, and the stable high-speed rotation of the motor 10 can be maintained.

[0128] On the other hand, in the Halbach magnet array, the interval between the adjacent permanent magnets 22 has a great influence on the magnetic field formed by the permanent magnets 22 (magnet portion 16). In the motor 10, the interval between the adjacent permanent magnets 22 is slightly separated by the spacer 46 of the magnet holder 40, and the interval between the adjacent permanent magnets 22 is determined. In addition, in the magnet holder 40, with respect to the reference length dimension lm, the thickness dimension d of the spacer 46 is in the range of 0 < d ≤ (lm × 1 / (n + 1)) × 1.5, and the interval dimension w between the adjacent permanent magnets 22 is 0 < w ≤ lm × 1 / (n + 1) × 1.5.

[0129] Generally, in the Halbach magnet array, the magnetic flux density at a position away from the arranged permanent magnets 22 by a specified distance affects the interval (interval dimension w) between the adjacent permanent magnets 22. When the interval between the adjacent permanent magnets 22 becomes wider, leakage magnetic flux occurs, resulting in a decrease in the magnetic flux density. This decrease in the magnetic flux density causes a decrease in the output torque of the motor 10.

[0130] Here, in the Heilbeck magnet array, when the angle θ = 360° / n (n is the number of divisions) and the spacing w between adjacent permanent magnets 22 is 1 / (n+1) of the length lm of the permanent magnet 22 along the arrangement direction (w = lm × 1 / (n+1)), the spatial higher harmonic components of the magnetic flux density distribution relative to a specified position of the permanent magnet 22 are approximately 0. For example, when the number of divisions n = 4, the spacing w = lm / 5, and the spatial higher harmonic components of the magnetic flux density distribution at a specified position of the permanent magnet 22 are approximately 0.

[0131] exist Figure 7A The diagram shows the ratio (%) of the fundamental component amplitude of the spatial magnetic flux density distribution relative to the gap center Gc of the double Helbeck magnet array with a spacing size w of the permanent magnet 22, when the magnetization direction angle θ = 90° (angle θ when the number of segments n = 4), and the ratio (%) of the volume of the permanent magnet 22. Furthermore, in... Figure 7B The figure shows the amplitude ratio (amplitude ratio %) of the 5th ((n+1)th) higher harmonic component relative to the fundamental component of the spatial magnetic flux density distribution corresponding to the spacing size w of the permanent magnet 22 at the gap center Gc with angle θ = 90°.

[0132] Furthermore, the ratio of the amplitude to the volume of the fundamental component of the spatial magnetic flux density distribution is set with the interval size w = 0 as a reference. Relative to the ratio of the amplitude to the volume of the fundamental component when the interval size w = 0, as the interval size w increases, the volume of the permanent magnet 22 decreases. In addition, in Figure 7A and Figure 7B In this process, the length dimension (radial length dimension) lm of the permanent magnet 22 on the armature 20 side along the arrangement direction is set to 10 mm, and the gap length 2G is set to 1.5 times the length dimension lm (2G = 15 mm).

[0133] like Figure 7A As shown, the volume ratio of permanent magnet 22 is approximately proportional to the amplitude of the fundamental wave relative to the spacing size w of permanent magnet 22. As the spacing size w of permanent magnet 22 increases, the volume ratio of permanent magnet 22 and the amplitude ratio of the fundamental wave component decrease.

[0134] In a dual Hellbeck magnet array, it is known that at an angle θ = 90°, a higher harmonic component of order (n+1) is generated in the magnetic field (within the gap). For example... Figure 7BAs shown, when the interval dimension w is 2 mm (= lm × 1 / (n + 1)), the ratio (amplitude ratio) of the amplitude of the fifth-order harmonic component to the amplitude of the fundamental wave component is minimized (roughly 0). Thus, it can be regarded that the fifth-order harmonic component disappears when the number of divisions n = 4 and the interval dimension w = 2 (mm).

[0135] The interval dimension w = 2 (mm) is 1 / 5 (equivalent to 1 / (n + 1)) with respect to the length dimension lm (mm) of the permanent magnet 22 when the number of divisions n = 4. In addition, as Figure 7A shown, when the interval dimension w = 2 mm, the amplitude of the fundamental wave decreases by approximately 20%.

[0136] In addition, as Figure 7B shown, within the range where the interval dimension w of the permanent magnet 22 does not exceed 3 mm (0 < w ≤ 3), the fifth-order harmonic component becomes the same ratio as the fifth-order harmonic component when w = 0, and no increase in the fifth-order harmonic component with respect to the fundamental wave component is found.

[0137] In Figure 8A it shows the fundamental wave amplitude ratio (%) of the spatial magnetic flux density distribution at the gap center of the double Halbach magnet array with respect to the interval dimension w of the permanent magnet 22, and the ratio (%) of the volume of the permanent magnet 22, in the case where the angle θ of the magnetization direction of the permanent magnet 22 is 45° (angle θ with respect to the number of divisions n = 8). In addition, in Figure 8B it shows the amplitude ratio (amplitude ratio %) of the ninth-order ((n + 1)-order) harmonic component of the spatial magnetic flux density distribution corresponding to the change in the interval dimension w of the permanent magnet २२ with respect to the fundamental wave component in the case where the angle θ = 45°. <000-0345>As Figure 8A shown, even in the case where the angle θ = 45°, the ratio of the volume of the permanent magnet 22 and the ratio of the fundamental wave amplitude are approximately proportional to the interval dimension w of the permanent magnet 22. As the interval dimension w of the permanent magnet 22 increases, the ratio of the volume of the permanent magnet 22 and the ratio of the fundamental wave amplitude decrease.

[0139] In addition, as Figure 8B shown, in the case where the angle θ = 45°, when the interval dimension w is approximately 1 mm (equivalent to lm × 1 / 9), the amplitude ratio is minimized (roughly 0), and it can be regarded that at this interval dimension w ≈ 1 (mm), the ninth-order harmonic component approximately disappears.

[0140] In addition, in the interval dimension w where the ninth-order harmonic component is regarded as disappearing, the amplitude of the fundamental wave decreases by approximately 10% (refer to <00-0352>)。The ratio of the amplitude of this fundamental wave is the same as the ratio when the interval size w = 0, and it becomes the interval size w = 1.7 (mm) (equivalent to w = lm × 1 / 9 × 1.5). Therefore, it is considered that within the range of the interval size w where 0 ≤ w ≤ 1.7, no increase in the 9th harmonic component with respect to the fundamental wave is found. This range of the interval size w is within the range not exceeding 1 / 9 of the length size lm along the arrangement direction of the permanent magnet 22 when the angle θ = 45° (the number of divisions n = 8) (= 1 / (n + 1)).

[0141] Therefore, it is preferable that the interval size w of the permanent magnet 22 in the Halbach magnet array is 0 ≤ w ≤ lm × 1 / (n + 1) × 1.5. Thus, in the Halbach magnet array (single Halbach magnet array and double Halbach magnet array), by setting the interval size w of the adjacent permanent magnets 22 within the range of 0 ≤ w ≤ lm × 1 / (n + 1) × 1.5 (where n is the number of divisions and lm is the length size along the arrangement direction on the armature 20 side of the permanent magnet 22), the increase in the harmonic component caused by the interval size w of the adjacent permanent magnets 22 can be suppressed. In addition, by setting the interval size w = lm × 1 / (n + 1), the harmonic component can be effectively suppressed.

[0142] In addition, if the thickness d of the spacer 46 provided in the magnet holder 40 is a size of lm × 1 / (n + 1) × 1.5 (mm) or less (0 < d ≤ lm × 1 / (n + 1) × 1.5), the increase in the harmonic component caused by the provision of the spacer 46 can be suppressed. In particular, by setting the thickness size d of the spacer of the magnet holder 40 = lm × 1 / (n + 1), the harmonic component can be effectively suppressed. Therefore, the magnet holder 40 only needs to adopt a size and material of the thickness size d of the spacer 46 within the above range and capable of obtaining the desired strength.

[0143] Therefore, the magnet holder 40 only needs to be formed with a thickness size d that satisfies the above conditions. In addition, the magnet holder 40 only needs to be formed in the following manner: regarding the cross-sectional area of the radial cross-section in the double Halbach magnet array, the ratio of the cross-sectional area between the gap center Gc and the inner Halbach magnet array to the cross-sectional area between the gap center Gc and the outer Halbach magnet array, and the ratio of the cross-sectional area of the inner Halbach magnet array to the cross-sectional area of the outer Halbach magnet array are the same. At this time, the magnet holder 40 only needs to be formed to include the spacer 46 in the area S4 of the inner Halbach magnet array corresponding to the magnet portion 16, and the magnet holder 40 only needs to be set so that the thickness size d of the spacer 46 includes the pole pitch τ and the length size lm of the permanent magnet 22 along the arrangement direction.

[0144] Furthermore, in the embodiment described above, a magnet holder 40 having an inner wall 42, an outer wall 44, and spacers 46 corresponding to the number of permanent magnets 22 was used as an example. However, the retaining member only needs to have at least an outer peripheral wall and spacers, and the inner peripheral wall can be omitted. In such a case, it is also possible to use a rotating shaft, such as the output shaft of a rotor, as the inner peripheral wall of the retaining member, and to install the permanent magnets by embedding them between the spacers of the retaining member while the retaining member is mounted on the rotating shaft.

[0145] Furthermore, the retaining member can also be structured such that an inner peripheral wall is used during the assembly of the permanent magnet, and then removed after assembly. Moreover, the retaining member only needs to be able to restrict the movement of the permanent magnet using an outer peripheral wall and a partition, or an outer peripheral wall, an inner peripheral wall, and a partition. The outer peripheral wall, inner peripheral wall, and partition can also be shaped to form an opening in a lattice or similar structure.

[0146] Furthermore, in this embodiment, the outer Hellbeck array magnet 34A in the magnetic field generating unit 32B is replaced with a ferromagnetic material 30A. However, the magnetic field generating unit may also be a structure in which the radially inner Hellbeck array magnet is replaced with a ferromagnetic material.

[0147] On the other hand, in this embodiment, a magnetic field generator 32A is used in the magnetic field generating section 24 of the electric motor 10, but a magnetic field generator 32B can also be used in the magnetic field generating section 24. That is, a dual Heilbeck magnet array can also be used in the rotating electric motor. Figure 9 In the figure, a top view is used to show the general structure of the electric motor 50 involved in the modified example.

[0148] like Figure 9 As shown, the magnetic field generating section 52 of the electric motor 50 uses a magnet section 54A as a first magnet section employing a Hellbeck array magnet 26A, and a magnet section 54B as a second magnet section employing a Hellbeck array magnet 26B. The magnet sections 54A and 54B are approximately annular, and the magnet section 54A is coaxially arranged within the magnet section 54B with a gap length of 2G, allowing it to rotate as a single unit. Furthermore, in the electric motor 50, an armature 20 is disposed between the magnet sections 54A and 54B, and the armature 20 is rotatable relative to the magnet sections 54A and 54B.

[0149] Thus, in the motor 50, by supplying three-phase alternating current to the coils 20U to 20W of the armature 20, the magnet parts 54A and 54B rotate relative to the armature 20 as a whole, and the output shaft 12A is driven to rotate.

[0150] Here, in magnet section 54A and magnet section 54B, a magnet retainer 56 as a first retaining member and a magnet retainer 58 as a second retaining member are used respectively. The basic structure of each of the magnet retainers 56 and 58 is the same as that of the magnet retainer 40. That is, the magnet retainer 56 is the same as the magnet retainer 40. In addition, in the magnet retainer 58, an inner wall 42A corresponding to the inner wall 42 and an outer wall 44A corresponding to the outer wall 44 are provided. A spacer 46 is arranged between the inner wall 42A and the outer wall 44A, and a socket 48A corresponding to the socket 48 is formed.

[0151] In the electric motor 50 configured in this way, by using magnet holders 56 and 58, the positions of each permanent magnet 22 (22A to 22D) can be restricted in the magnet sections 54A and 54B respectively, making the assembly of the permanent magnets 22 easier. As a result, even in the electric motor 50, it can be manufactured as easily as in the electric motor 10.

[0152] Furthermore, in the embodiments and variations described above, the example of a division number n = 4 was mainly used. However, any integer greater than 3 can be used for the division number n. Moreover, in motors driven by three-phase AC power, from the viewpoint of further controlling torque fluctuations with higher precision, n = 3·k + 2 (where k is a positive integer) is preferably chosen as the division number n. This effectively suppresses torque fluctuations generated by power supplies using three-phase AC power.

[0153] Furthermore, in this embodiment and its variations, electric motors 10 and 50 are used as examples for explanation. However, the rotating electric motor can also be a generator that produces three-phase alternating current through rotation. By using a generator as a rotating electric motor, the output density of the generator can be increased.

[0154] Furthermore, in this embodiment and its variations, electric motors 10 and 50 will be used as examples for explanation. However, the rotary motor can be used in a vehicle as a drive source in traction mode and as a regenerative generator in deceleration mode (regenerative mode). In this case, even if the direction of the current reverses when switching between traction and regenerative modes, the magnetic energy stored in the armature can be suppressed (reduced). Therefore, in the rotary motor, the induced voltage generated during current switching can be reduced, thus suppressing damage to the drive circuit that drives the rotary motor. Moreover, the rotary motor can provide responsive operating characteristics in a vehicle.

[0155] The entire contents disclosed in Japanese Patent Application 2019-17162 are incorporated herein by reference.

[0156] All documents, patent applications and technical standards described in this specification are incorporated herein by reference to each other to the same extent as the specific and individually described cases.

Claims

1. A magnetic field generating device comprising: a magnet portion in which a plurality of permanent magnets are arranged in a circumferential direction with their magnetization directions sequentially changed at angles obtained by dividing one cycle of electrical angle by a division number n of any one of an integer of three or more, and a holding member that uses a non-magnetic material and has an outer peripheral wall in a circular ring shape against which outer peripheral surfaces of the permanent magnets abut against inner peripheral surfaces thereof, and a plurality of partitions that are respectively provided in a protruding manner from inner surfaces of the outer peripheral wall to an inner side in a radial direction in the circumferential direction of the outer peripheral wall, in which the permanent magnets are respectively embedded between adjacent ones of the partitions, a thickness dimension d of the partitions is set in accordance with a length dimension lm of one side in a direction of arrangement in a cross section of the permanent magnet in a magnetization direction, which is set as a reference in advance, and the division number n, the thickness dimension d of the partitions satisfies: 0 < d ≤ lm x 1 / (n+1) x 1.

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2. A magnetic field generating device comprising: a magnet portion in which a plurality of permanent magnets are arranged in a circumferential direction with their magnetization directions sequentially changed at angles obtained by dividing one cycle of electrical angle by a division number n of any one of an integer of three or more, and a holding member that uses a non-magnetic material and has an outer peripheral wall in a circular ring shape against which outer peripheral surfaces of the permanent magnets abut against inner peripheral surfaces thereof, and a plurality of partitions that are respectively provided in a protruding manner from inner surfaces of the outer peripheral wall to an inner side in a radial direction in the circumferential direction of the outer peripheral wall, in which the permanent magnets are respectively embedded between adjacent ones of the partitions, a thickness dimension d of the partitions is set in accordance with a length dimension lm of one side in a direction of arrangement in a cross section of the permanent magnet in a magnetization direction, which is set as a reference in advance, and the division number n, the thickness dimension d of the partitions satisfies: d = lm / (n+1).

3. The magnetic field generating device according to claim 1 or 2, wherein the holding member includes an inner peripheral wall against which inner peripheral surfaces of the permanent magnets abut against an outer peripheral surface thereof, and radially inner side ends of the partitions are joined to the outer peripheral surface of the inner peripheral wall.

4. The magnetic field generating device according to claim 1 or 2, wherein the magnetic field generating device includes a ferromagnetic body that is formed in a circular ring shape facing the permanent magnets of the magnet portion and is disposed so as to be relatively rotatable with respect to the magnet portion, and a magnetic field is formed between the ferromagnetic body and the magnet portion by a magnetic force of the magnet portion.

5. The magnetic field generating device according to claim 1 or 2, wherein the magnet portion includes a first magnet portion in which the plurality of permanent magnets are arranged in a circumferential direction, and a second magnet portion that is disposed on a radially outer side of the first magnet portion and in which the plurality of permanent magnets are arranged in a circumferential direction, and is integrally rotatable with the first magnet portion, the holding member includes a first holding member that respectively holds the plurality of permanent magnets of the first magnet portion, and a second holding member that respectively holds the plurality of permanent magnets of the second magnet portion.

6. A rotary electric machine comprising: the magnet portion, a plurality of permanent magnets are arranged in a circumferential direction with a magnetization direction being changed in order at an angle obtained by dividing one cycle of electrical angle by a division number n of any one of an integer of three or more, a holding member that uses a non-magnetic material and has a circular ring-shaped outer peripheral wall against which an outer peripheral surface of each of the permanent magnets abuts on an inner peripheral surface of the outer peripheral wall, and a plurality of partitions that are respectively provided projecting from an inner surface of the outer peripheral wall to an inner side in a radial direction in the circumferential direction of the outer peripheral wall, and in which the permanent magnets are respectively embedded between adjacent ones of the partitions, and an armature that is arranged so as to be relatively rotatable with respect to the magnet portion in which each of the permanent magnets is held by the holding member, a thickness dimension d of the partition is set in accordance with a length dimension lm of one side in a direction of arrangement in a cross section of the permanent magnet in a magnetization direction that is set in advance as a reference, and the division number n, the thickness dimension d of the partition satisfies: 0 < d ≤ lm x 1 / (n+1) x 1.

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7. A rotary electric machine comprising: the magnet portion, a plurality of permanent magnets are arranged in a circumferential direction with a magnetization direction being changed in order at an angle obtained by dividing one cycle of electrical angle by a division number n of any one of an integer of three or more, a holding member that uses a non-magnetic material and has a circular ring-shaped outer peripheral wall against which an outer peripheral surface of each of the permanent magnets abuts on an inner peripheral surface of the outer peripheral wall, and a plurality of partitions that are respectively provided projecting from an inner surface of the outer peripheral wall to an inner side in a radial direction in the circumferential direction of the outer peripheral wall, and in which the permanent magnets are respectively embedded between adjacent ones of the partitions, and an armature that is arranged so as to be relatively rotatable with respect to the magnet portion in which each of the permanent magnets is held by the holding member, a thickness dimension d of the partition is set in accordance with a length dimension lm of one side in a direction of arrangement in a cross section of the permanent magnet in a magnetization direction that is set in advance as a reference, and the division number n, the thickness dimension d of the partition satisfies: d = lm / (n+1).

8. The rotary electric machine according to claim 6 or 7, wherein the rotary electric machine includes a ferromagnetic body that is formed in a circular ring shape facing each of the permanent magnets of the magnet portion, and is arranged so as to be relatively rotatable with respect to the magnet portion, and a three-phase coil of the armature is arranged in a circumferential direction on a surface on the magnet portion side.

9. The rotary electric machine according to claim 6 or 7, wherein the magnet portion includes a first magnet portion in which the plurality of permanent magnets are arranged in a circumferential direction, and a second magnet portion that is arranged on a radially outer side of the first magnet portion, in which the plurality of permanent magnets are arranged in a circumferential direction, and that is integrally rotatable with the first magnet portion, the holding member includes a first holding member that holds the plurality of permanent magnets of the first magnet portion, and a second holding member that holds the plurality of permanent magnets of the second magnet portion, the armature has a three-phase coil arranged in a circumferential direction between the first magnet portion and the second magnet portion.

10. The rotary electric machine according to claim 6 or 7, wherein The holding member includes an inner peripheral wall, and an inner peripheral surface of each of the permanent magnets abuts against an outer peripheral surface of the inner peripheral wall, and a radially inner side end of each of the partition plates is joined to the outer peripheral surface of the inner peripheral wall.

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