JP7700722B2 - Rotor and method for manufacturing the rotor - Google Patents

Description

This disclosure relates to a rotor having a permanent magnet and a method for manufacturing the rotor.

A motor rotor is known that is configured with multiple permanent magnets arranged on the side of the rotor base as the magnetic pole portion. One example of the permanent magnet is a Halbach array magnet (see, for example, Patent Document 1). The use of a Halbach array magnet is expected to improve the performance of the motor.

JP 2020-137387 A

A Halbach array magnet is a magnet in which d-axis magnet parts, in which the magnetic flux is mainly oriented in the radial direction, and q-axis magnet parts, in which the magnetic flux is mainly oriented in the circumferential direction, are arranged alternately in the circumferential direction. Due to the configuration of this magnet, it is difficult to magnetize the unmagnetized magnet material after it is attached to the rotor base. Therefore, when using a Halbach array magnet in a rotor, it is common to magnetize each of the magnet materials that will become the d-axis magnet parts and the q-axis magnet parts in advance, and then attach each of the magnetized magnet materials to the rotor base.

However, when attaching the magnetized magnet materials of the d-axis magnet section and the q-axis magnet section to the rotor base, for example, an attractive force acts between the magnet material of the d-axis magnet section that is attached later and the magnet material of the q-axis magnet section that is attached first. In other words, when attaching the magnet materials, the magnet materials are in a situation where they may come into contact with each other due to the effect of their mutual attractive forces. For this reason, there was a concern that the magnetic materials could be damaged if the magnetic materials came into strong contact with each other. In other words, it was necessary to perform careful and complicated attachment work to prevent the magnetic materials from coming into strong contact with each other.

The objective of this disclosure is to provide a rotor and a method for manufacturing the rotor that can be easily installed while preventing damage to the magnetic material that constitutes the Halbach array magnet.

The rotor that solves the above problem is a rotor (12) that includes a rotor base (21) and a plurality of permanent magnets (22) arranged in the circumferential direction on the side surface (21a) of the rotor base, the permanent magnets being configured as Halbach array magnets, and the permanent magnets are integrally configured as a single magnetic material with d-axis magnet sections (22dn, 22ds) on both sides in the circumferential direction, whose magnetic flux is mainly oriented in the radial direction, and a q-axis magnet section (22q) in the circumferential center, whose magnetic flux is mainly oriented in the circumferential direction, and the d-axis magnet sections of the permanent magnets that are adjacent in the circumferential direction and have the same polarity are arranged in a row.

The manufacturing method of a rotor that solves the above problem is a manufacturing method of a rotor (12) that includes a rotor base (21) and a plurality of permanent magnets (22) arranged in the circumferential direction on the side surface (21a) of the rotor base, the permanent magnets being composed of Halbach array magnets, and the permanent magnets are integrally constructed as a single magnetic material with d-axis magnet sections (22dn, 22ds) on both sides in the circumferential direction, whose magnetic flux is mainly oriented in the radial direction, and a q-axis magnet section (22q) in the circumferential center, whose magnetic flux is mainly oriented in the circumferential direction, and the permanent magnets are attached to the side surface of the rotor base alternately in the circumferential direction over the entire circumference or over a part of the circumferential direction, and then the next permanent magnet is inserted and attached between the previously attached permanent magnets from the radial direction, so that the d-axis magnet sections of the same polarity of the permanent magnets adjacent in the circumferential direction are arranged consecutively.

According to the rotor and rotor manufacturing method described above, the permanent magnet of the rotor is made of a d-axis magnet part on both sides in the circumferential direction, in which the magnetic flux is mainly oriented in the radial direction, and a q-axis magnet part in the circumferential center, in which the magnetic flux is mainly oriented in the circumferential direction, which are integrally configured as a single magnet material. The d-axis magnet parts of the same polarity of the permanent magnets adjacent to each other in the circumferential direction of the rotor are arranged in a continuous line. In a rotor using a Halbach array magnet, magnetized magnet material is attached, but by configuring and arranging each permanent magnet as described above, the magnetic force generated between the first permanent magnet attached and the second permanent magnet attached is a repulsive force rather than an attractive force. In other words, since the first permanent magnet attached and the second permanent magnet attached are attached using a repulsive force, the occurrence of the event in which the first permanent magnet and the second permanent magnet strongly come into contact with each other due to the attractive force is suppressed, and the occurrence of damage to the permanent magnet due to this is suppressed. In other words, strong contact due to the attraction between the permanent magnets during installation is unlikely to occur, and the installation work of the permanent magnets is expected to be easier.

FIG. 1 is a configuration diagram of a motor having a rotor according to an embodiment. FIG. 2 is a perspective view of a rotor in the embodiment. FIG. 2 is a partially enlarged view of the rotor in the embodiment. 5A to 5C are explanatory diagrams showing a manufacturing process of the rotor in the embodiment.

An embodiment of a rotor and a method for manufacturing the rotor will now be described.
(Configuration of Motor 10)
As shown in Fig. 1, the motor 10 of this embodiment includes a stator 11 and a rotor 12. The stator 11 is configured in a substantially annular shape. The stator 11 has, for example, 24 coil magnetic pole portions (not shown) in the circumferential direction. The rotor 12 is rotatably arranged inside the stator 11. The stator 11 generates a rotating magnetic field for driving the rotor 12 to rotate based on the passage of electricity through its own coil magnetic pole portions. The motor 10 of this embodiment is intended to be applied to a motor with high speed rotation specifications, for example, a maximum operating speed of 12,000 rpm or more.

(Configuration of rotor 12)
As shown in FIGS. 1 and 2 , the rotor 12 of this embodiment includes a rotor base 21 , a permanent magnet 22 , and a shatterproof member 23 .

The rotor base 21 is generally cylindrical. The rotor base 21 has a hollow structure that takes weight reduction into consideration. The axial end of the rotor base 21 is integrally formed as the output shaft 21x. For example, 20 permanent magnets 22 are arranged in the circumferential direction on the outer surface 21a of the axial center of the rotor base 21. In this embodiment, the outer surface 21a of the rotor base 21 has 20 flat surfaces corresponding to each permanent magnet 22 (see FIG. 3). The rotor 12 has 20 magnetic poles in the circumferential direction.

The permanent magnet 22 has a substantially rectangular shape. The inner surface 22a of the permanent magnet 22, which is the inner diameter side of the rotor 12, abuts against the outer surface 21a of the rotor base 21. The inner surface 22a of the permanent magnet 22 is a flat surface and abuts against the outer surface 21a of the rotor base 21 with the flat surfaces. The outer surface 22b of the permanent magnet 22, which is the outer diameter side of the rotor 12, constitutes a uniform outer peripheral surface of the rotor 12 with the entire permanent magnet 22 in the circumferential direction. The side end surfaces 22c on both sides of the permanent magnet 22 in the circumferential direction of the rotor 12 are flat surfaces along the radial direction of the rotor 12. In order to abut its inner surface 22a against the rotor base 21, the permanent magnet 22 has a gap at each of the side end surfaces 22c on both sides of the permanent magnet 22 on both sides in the circumferential direction, or only the side end surface 22c on one side is abutted. In each figure, the permanent magnets 22 are depicted as abutting against each other.

As shown in FIG. 3, the permanent magnet 22 is configured as a Halbach array magnet in this embodiment. Specifically, the permanent magnet 22 is divided into three parts with different magnetization patterns in the circumferential direction. The circumferential sides of the permanent magnet 22 are d-axis magnet parts 22dn, 22ds in which the magnetic flux is mainly oriented in the radial direction. The circumferential center part of the permanent magnet 22 is a q-axis magnet part 22q in which the magnetic flux is mainly oriented in the circumferential direction and faces the d-axis magnet parts 22dn, 22ds on both sides of the permanent magnet 22. A more specific configuration of the permanent magnet 22 and a method of mounting it to the rotor base 21 will be described later.

As shown in FIG. 2, the shatterproof member 23 is attached in a manner that it encircles the rotor 12 along the outer surfaces 22b of the multiple permanent magnets 22 in the circumferential direction. The shatterproof member 23 is provided, for example, in a cylindrical shape so as to completely cover the permanent magnets 22. The shatterproof member 23 is made of, for example, carbon fiber reinforced plastic (CFRP). A ribbon-shaped material (not shown) of CFRP is wound around the permanent magnets 22 of the rotor 12 several times, and is wound in one or multiple layers. It is then heated and hardened to produce a cylindrical shatterproof member 23 that fixes the permanent magnets 22 and prevents them from scattering.

(Specific Configuration and Mounting Method of Permanent Magnet 22)
As shown in Fig. 3, in the permanent magnet 22 of this embodiment, the d-axis magnet portions 22dn, 22ds and the q-axis magnet portion 22q are integrally formed as a single magnet material. The d-axis magnet portions 22dn, 22ds are provided on both circumferential sides of the permanent magnet 22, and the q-axis magnet portion 22q is provided in the circumferential center. The d-axis magnet portion 22dn on one circumferential side has an N pole on the outer surface 22b of the permanent magnet 22, and the d-axis magnet portion 22ds on the other circumferential side has an S pole on the outer surface 22b of the permanent magnet 22. The circumferential arrangement of each permanent magnet 22 in the rotor 12 is such that the d-axis magnet portions 22dn and d-axis magnet portions 22ds of the same pole of each circumferentially adjacent permanent magnet 22 are aligned consecutively. In other words, in this embodiment, the d-axis magnet portions 22dn and the d-axis magnet portions 22ds of the same polarity of adjacent permanent magnets 22 cooperate with each other to form magnet pole portions of the same polarity.

In addition, in this embodiment, the permanent magnets 22 are attached every other one around the entire circumference of the rotor base 21 to the outer surface 21a of the rotor base 21, and then every other remaining permanent magnet 22 is attached to fill the gaps between the previously attached permanent magnets 22. Note that a permanent magnet 22 may be attached with a gap of one magnet, and then the next permanent magnet 22 may be attached to fill the gaps between the permanent magnets 22, and this may be repeated around the entire circumference of the rotor base 21. In any case, the permanent magnet 22 to be attached later is attached in such a way that it is inserted from the outside to the inside in the radial direction between the previously attached permanent magnets 22 with a gap of one magnet.

Taking into consideration such mounting aspects, the radially inner portion 22e of each permanent magnet 22 is configured so that the corners of each d-axis magnet portion 22dn, 22ds that are continuous with the inner surface 22a are inclined surfaces 22f, and the shape tapers radially inward. In other words, in this embodiment, in which the permanent magnet 22 is inserted between previously installed permanent magnets 22, the radially inner portion 22e, which is the tip of the insertion side of the permanent magnet 22, is tapered. Therefore, the permanent magnet 22 to be installed later is less likely to come into contact with the previously installed permanent magnets 22 on both sides in the circumferential direction, which is expected to make it easier to install the permanent magnets 22.

In addition, since each permanent magnet 22 has d-axis magnet parts 22dn, 22ds on both sides and q-axis magnet part 22q in the center, the internal magnetic flux tends to be directed toward the center as it moves radially inward. In other words, the radially inner corners that are omitted by providing inclined surfaces 22f that make the radially inner part 22e of the permanent magnet 22 have a tapered shape are originally parts with little internal magnetic flux, so the impact on the performance of the permanent magnet 22 is sufficiently small. In this embodiment, the flow of internal magnetic flux of the permanent magnet 22 is further taken into consideration, and the magnetization of the d-axis magnet parts 22dn, 22ds itself is inclined to be magnetized along the inclined surfaces 22f. In other words, the d-axis center line Ld is set to have a predetermined inclination angle θ1 with respect to the q-axis center line Lq, which is also the circumferential center line of the permanent magnet 22. In this embodiment, in which 20 permanent magnets 22 are used, the inclination angle θ1 of the d-axis center line Ld is set to 30° to 40° as an example. Combined with the inclined magnetization of the d-axis magnet sections 22dn and 22ds, the impact on the performance of the permanent magnet 22 is sufficiently small, making the permanent magnet 22 of this embodiment a rational configuration.

(Operation of this embodiment)
The operation of this embodiment will be described.
In the manufacture of the rotor 12 of this embodiment, the permanent magnets 22 are configured as Halbach array magnets, so that a plurality of pre-magnetized permanent magnets 22 are attached.

First, the permanent magnets 22 are attached to the outer surface 21a of the rotor base 21, one every other magnet, all around the circumference. The outer surface 21a of the rotor base 21 and the inner surface 22a of each permanent magnet 22 are in contact with each other flat surfaces. Next, the remaining permanent magnets 22 are inserted radially from the outside toward the inside between the previously attached permanent magnets 22 that are alternately attached in the circumferential direction. In this case, the d-axis magnet portions 22dn, 22ds on both sides of the later-attached permanent magnet 22 to be inserted and the d-axis magnet portions 22dn, 22ds of the previously-attached permanent magnets 22 on both sides are arranged to have the same polarity.

Therefore, as shown in FIG. 4, the rear-attached permanent magnet 22 receives an equal repulsive force F1 from the front-attached permanent magnets 22 on both sides. This prevents the occurrence of a conventional concern in which the front-attached permanent magnet 22 and the rear-attached permanent magnet 22 come into strong contact with each other due to the attractive force acting between them. In other words, the occurrence of damage due to strong contact between the permanent magnets 22 during installation due to the action of the attractive force of the permanent magnets 22 is prevented. In other words, since strong contact due to the attraction between the permanent magnets 22 does not occur, the installation work of the permanent magnets 22 can be made relatively easy.

In addition, the radially inner portion 22e, which is the insertion end of each permanent magnet 22, is provided with an inclined surface 22f to form a tapered shape, which makes it easier to insert the later-attached permanent magnet 22 between the previously-attached permanent magnets 22. In other words, this is also expected to facilitate the installation work of the permanent magnets 22.

The permanent magnets 22 attached in this manner also have their own inner surface 22a and the outer surface 21a of the rotor base 21 abutting on each other in a flat manner. Therefore, all of the permanent magnets 22 are attached to the rotor base 21 in a state where they are prevented from rotating around the entire circumference. After that, anti-scattering members 23 are attached so as to cover each permanent magnet 22, and each permanent magnet 22 is more securely fixed, completing the rotor 12.

(Effects of this embodiment)
The effects of this embodiment will be described.
(1) The permanent magnet 22 of the rotor 12 is formed by integrating the d-axis magnet parts 22dn, 22ds, whose magnetic flux is mainly oriented in the radial direction, on both sides in the circumferential direction, and the q-axis magnet part 22q, whose magnetic flux is mainly oriented in the circumferential direction, in the circumferential center part, into one magnet material. The d-axis magnet parts 22dn, 22ds of the same polarity of the permanent magnets 22 adjacent to each other in the circumferential direction of the rotor 12 are arranged in a continuous line. Here, in the rotor 12 of this embodiment using the Halbach array magnet, the magnet material is already magnetized. However, by configuring and arranging each permanent magnet 22 as described above, the magnetic force generated between the first permanent magnet 22 and the later permanent magnet 22 is a repulsive force F1, not an attractive force. In other words, since the first permanent magnet 22 and the later permanent magnet 22 are attached using the repulsive force F1, the occurrence of the event in which the two come into strong contact with each other due to the attractive force is suppressed, and the occurrence of damage to the permanent magnet 22 due to this can be suppressed. In other words, strong contact due to attraction between the permanent magnets 22 during installation is unlikely to occur, and therefore it is expected that the installation work of the permanent magnets 22 will be made easier.

(2) The permanent magnets 22 are arranged with their flat surfaces abutting against the outer surface 21a of the rotor base 21. In other words, the permanent magnets 22 are attached to the rotor base 21 in a state where they are prevented from rotating, which contributes to improving the fixing strength of the permanent magnets 22 in the direction of rotation of the rotor 12.

(3) The radially inner portion 22e of the permanent magnet 22, which faces the outer surface 21a of the rotor base 21, has a tapered shape. In other words, when the permanent magnet 22 to be installed later is inserted into the permanent magnets 22 previously installed on both sides in the circumferential direction, contact is unlikely to occur, and it is expected that the installation of the permanent magnets 22 will be made easier.

(4) The permanent magnet 22 is provided with an inclined surface 22f for tapering the radially inner portion 22e. The d-axis magnet portions 22dn and 22ds of the permanent magnet 22 where the inclined surface 22f is located are magnetized with an inclination along the inclined surface 22f, so that the effect on the performance of the permanent magnet 22 can be kept sufficiently small.

(Example of change)
This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

The various numerical values described above are examples and may be changed as appropriate.
Although the shatterproof member 23 is provided to cover the entire permanent magnet 22, the permanent magnet 22 may be partially exposed. Also, the shatterproof member 23 may be omitted.

The shape of the permanent magnet 22 is an example and may be changed as appropriate. For example, the permanent magnet 22 does not need to have an inclined surface 22f. The inner surface 22a of the permanent magnet 22 may be a circumferential surface. In this case, the shape of the outer surface 21a of the rotor base 21 is also changed accordingly.

The configuration of the rotor 12 may be changed as appropriate.
Although the present invention is applied to an inner rotor type in which the rotor 12 is located radially inside the stator 11, the present invention may be applied to an outer rotor type in which the rotor 12 is located radially outside the stator 11.

Although the present invention is applied to a radial type in which the rotor 12 and the stator 11 face each other in the radial direction, it may be applied to an axial type in which the rotor and the stator face each other in the axial direction.
(Additional Note)
The technical ideas that can be understood from the above-described embodiment and modified examples will be described.

(A) a rotor (12) including a rotor base (21) and a plurality of permanent magnets (22) arranged in the circumferential direction of a side surface (21a) of the rotor base, the permanent magnets being configured as Halbach array magnets;
A motor (10) comprising a stator (11) that generates a rotating magnetic field for driving the rotor,
The permanent magnet of the rotor is integrally formed as a single magnet material, with d-axis magnet sections (22dn, 22ds) at both circumferential sides, in which the magnetic flux is mainly oriented in the radial direction, and a q-axis magnet section (22q) at the circumferential center, in which the magnetic flux is mainly oriented in the circumferential direction,
The d-axis magnet portions of the permanent magnets having the same polarity and adjacent to each other in the circumferential direction are arranged in a continuous line.
Motor.

12 rotor, 21 rotor base, 21a outer surface (side), 22 permanent magnet, 22dn, 22ds d-axis magnet section, 22q q-axis magnet section

Claims (5)

A rotor base (21);
a plurality of permanent magnets (22) arranged in a circumferential direction on a side surface (21a) of the rotor base,
The rotor (12) is configured with a Halbach array magnet,
The permanent magnet is integrally formed as a single magnet material including d-axis magnet sections (22dn, 22ds) at both circumferential sides, in which the magnetic flux is mainly oriented in the radial direction, and a q-axis magnet section (22q) at the circumferential center, in which the magnetic flux is mainly oriented in the circumferential direction,
The d-axis magnet portions of the permanent magnets having the same polarity and adjacent to each other in the circumferential direction are arranged in a continuous line,
A circumferential side end surface (22c) of the permanent magnet forms a flat surface along the radial direction of the rotor,
A portion (22e) of the permanent magnet facing the side surface of the rotor base has an inclined surface (22f) for forming a tapered shape,
The inclined surface is formed so as to be continuous with the side end surface (22c) and the radial inner surface (22a) of the permanent magnet,
In the permanent magnet, the side end surface and the inclined surface continuing radially inward from the side end surface are inclined with respect to the side end surface along the radial direction of the rotor.
Rotor. The permanent magnets are arranged such that their flat surfaces abut against each other on the side surface of the rotor base.
The rotor of claim 1 . In the permanent magnets adjacent in the circumferential direction, the inclined surfaces adjacent in the circumferential direction are not in contact with each other and have a gap between the inclined surfaces.
The rotor of claim 1 . The d-axis magnet portion is magnetized with an inclination along the inclined surface.
The rotor of claim 1 . A rotor base (21);
a plurality of permanent magnets (22) arranged in a circumferential direction on a side surface (21a) of the rotor base,
A method for manufacturing a rotor (12) in which the permanent magnet is a Halbach array magnet, comprising:
The permanent magnet is formed integrally as a single magnet member, with d-axis magnet sections (22dn, 22ds) on both circumferential sides, the magnetic flux of which is mainly oriented in the radial direction, and a q-axis magnet section (22q) in the circumferential center, the magnetic flux of which is mainly oriented in the circumferential direction,
The permanent magnets are attached to the side surface of the rotor base at every other magnet in the circumferential direction over the entire circumference or over a part of the circumferential direction, and then the next permanent magnet is inserted between the previously attached permanent magnets from the radial direction and attached so that the d-axis magnet portions of the same polarity of the permanent magnets adjacent in the circumferential direction are arranged consecutively.
A method for manufacturing a rotor.

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