Permanent magnet motor

Abstract

To provide a permanent magnet motor including a rotor having main magnets and auxiliary magnets whose magnetic orientations are different from each other.SOLUTION: A permanent magnet motor according to the present embodiment includes: a rotor including a magnet, the magnet being constituted of a plurality of main magnets and a plurality of auxiliary magnets, the main magnets being magnetically oriented in a first direction, the auxiliary magnets being magnetically oriented in a second direction different from the first direction, the auxiliary magnets being disposed respectively between the main magnets; a stator; and a magnetic sensor of which a position is fixed with respect to the stator. In the rotor, it is arranged so that one end of a side where the main magnets face the stator is engaged with a position facing the magnetic sensor and one end of a side where the auxiliary magnets face the stator is not engaged with the position.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] Embodiments of the present invention relate to a permanent magnet motor including a rotor having a main magnet and an auxiliary magnet with different magnetic orientations respectively.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a Halbach array magnet as follows. A plurality of first magnets magnetized in the radial direction are arranged at predetermined intervals in a ring-shaped space to form a plurality of second cavities in which circumferential wall surfaces are formed by the first magnets. When the second cavities are filled with a molten resin for magnet manufacturing, the filled molten resin is magnetized in the circumferential direction by a second magnetizing portion disposed in the vicinity of the second cavities, and the first magnet and the second magnet are taken out from the ring-shaped space. Thereby, the Halbach array magnet is resin-molded.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, a fixed mold and a movable mold are used for the above manufacturing, and the second magnetizing portion for magnetizing the second magnet in the circumferential direction is disposed in the movable mold. This second magnetizing portion has a complicated structure as described in paragraph

[0044] of Patent Document 1, and it is very difficult to magnetize in the circumferential direction when filling the second cavity with the molten resin using such a second magnetizing portion.

[0005] Therefore, a permanent magnet motor including a rotor that can more easily manufacture a rotor magnet including a main magnet and an auxiliary magnet with different magnetic orientations respectively is provided.

Means for Solving the Problems

[0006] The permanent magnet motor of this embodiment includes a plurality of main magnets magnetically oriented in a first direction, and the first direction and orthogonal Magnetically oriented in a second direction, between the main magnets alternately every other one A rotor including magnets composed of a plurality of auxiliary magnets arranged therein, A stator, A magnetic sensor whose position is fixed with respect to this stator, and has The first direction is the direction in which the magnetic sensor is located at its extension end, In the rotor, one end portion of the main magnet in the direction facing the stator is engaged with a position facing the magnetic sensor, and one end portion of the auxiliary magnet in the direction facing the stator is not engaged with this position.

Brief Description of the Drawings

[0007]

Figure 1

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Figure 5

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Figure 12

Mode for Carrying Out the Invention

[0008] (First Embodiment) FIG. 1 shows a divided resin molded part 1 of a rotor magnet provided with a Halbach array magnet according to this embodiment. The divided resin molded part 1 is molded by resin 4 with eight main magnets 2 and auxiliary magnets 3 arranged alternately, forming an arc shape with a central angle of 60 degrees. The main magnet 2 has longitudinal × transverse dimensions of 30 × 10.42 [mm], and the auxiliary magnet 3 has longitudinal × transverse dimensions of 30 × 5.25 [mm]. The thickness dimension of the auxiliary magnet 3 is set to be slightly thinner than that of the main magnet 2. The height dimension of the divided resin molded part 1 is 38 mm, and in the upper part in the figure, a step is formed so that the upper surface of the auxiliary magnet 3 is 2 mm higher than that of the main magnet 2. In this embodiment, the longitudinal direction of the magnets 2 and 3 is the axial direction, that is, the above-mentioned vertical direction. The lateral width dimension of the divided resin molded part 1 is 104.37 mm, and the vertical width dimension is 70.76 mm.

[0009] FIG. 2 is an image of the case of resin molding the divided resin molded part 1. At this stage, the main magnet 2 is not magnetized, and the auxiliary magnet 3 is magnetized in the circumferential direction. The main magnet 2 and the auxiliary magnet 3 are alternately arranged and accommodated in the cores 5 and the cavity 6, which are molds. Positioning bushings 7, magnet protruding pins 8, and resin part protruding pins 9 are arranged below the core 5 in the figure. On the other hand, magnet holding pins 10 and resin filling gates 11 are arranged on the cavity 6 side in the upper part in the figure. Resin 4 is filled from the resin filling gate 11 for molding.

[0010] Figure 3 is a flowchart showing the manufacturing process of the rotor. The unmagnetized main magnet 2 and the magnetized auxiliary magnet 3 are respectively inserted into the resin mold (S1, S2), and the two magnets 2 and 3 are alternately arranged in an arc shape (S3). Then, the two magnets 2 and 3 are fixed by the magnet protruding pins 8 (S4), and the resin 4 is filled from a plurality of gates 11 (S5). When the molded split resin molded part 1 is taken out (S6), it is inserted into the magnetization device (S7) and the main magnet 2 is magnetized (S8). At this point, the split resin molded part 1 is completed (S9). When six split resin molded parts 1 are assembled in a ring shape to form a circumference (S10), they are inserted into the inner peripheral side of the rotor yoke 12 shown in Figure 4 (S11), and the rotor 13 is completed (S12).

[0011] Figures 5 and 6 show an example in which a magnetic sensor such as a hall sensor is arranged to detect the rotational position of the rotor 13. Also, in these figures, a part of the stator 23 including the stator yoke 21 and the coil 22 is also shown. In the figure, the lower end face of the auxiliary magnet 3 that is on top is at a position equivalent to the lower end face of the rotor yoke 12 or slightly lower than the lower end face. In contrast, the lower end face of the main magnet 2 is higher than the lower end face of the rotor yoke 12. That is, the lower end faces of the two magnets 2 and 3 are arranged so as to form a step, that is, unevenness.

[0012] And, for example, three magnetic sensors 24 are supported by a support member (not shown) with a slight gap from the lower end face of the rotor yoke 12 as shown in Figure 6. Thus, when the rotor 13 rotates, the magnetic sensor 24 is at a position where the recess in the above-described uneven arrangement of the lower end faces is engaged. Note that the rotor 13, the stator 23, and the magnetic sensor 24 constitute a radial gap type permanent magnet motor 25.

[0013] FIG. 7 shows the waveform of the signal output by the magnetic sensor when the magnetic sensor is arranged as shown in FIGS. 5 and 6 and the rotor 13 is rotating. FIG. 8 shows the same waveform when there is no step in the axial arrangement of the main magnet 2 and the auxiliary magnet 3. By providing a step, the leakage magnetic flux is suppressed, there is no dropout or variation in the output signal of the magnetic sensor, and the magnetic pole discrimination can be stably performed.

[0014] In addition, in the present embodiment, since the vertical dimensions of the main magnet 2 and the auxiliary magnet 3 are equal, a step is provided on the lower end surface side on the side where the magnetic sensor 24 is arranged, so that a step is also formed on the upper end surface side. Instead of this, by making the vertical dimensions of the main magnet 2 and the auxiliary magnet 3 different, the upper end surface side can also have a structure without a step.

[0015] As described above, according to the present embodiment, when manufacturing a Halbach array magnet including a plurality of main magnets 2 magnetically oriented in the radial direction and a plurality of auxiliary magnets 3 magnetically oriented in the circumferential direction and arranged between the main magnets 2 as a rotor magnet, the non-magnetized main magnet 2 and the circumferentially magnetized auxiliary magnet 3 are resin-molded in a state where they are arranged in an arc shape obtained by dividing the circumference into a plurality of parts to generate a divided resin-molded part 1. Then, the main magnet 2 of each divided resin-molded part 1 is magnetized in the radial direction, and the plurality of divided resin-molded parts 1 are connected in a circumferential shape. Thereby, the assemblability of the rotor magnet having a Halbach array magnet can be simplified. Further, since the plurality of divided resin-molded parts 1 are connected after magnetizing the magnets 2 and 3, the magnetization of each of the magnets 2 and 3 can be easily performed.

[0016] In this case, by setting the radial thickness dimension of the auxiliary magnet 3 to be thinner than that of the main magnet 2, the rigidity of the divided resin-molded part 1 can be improved. Further, by providing a step on the end surface side where the main magnet 2 and the auxiliary magnet 3 face the magnetic sensor, the rigidity of the divided resin-molded part 1 can be improved, and it becomes possible to stably perform magnetic pole discrimination by the magnetic sensor.

[0017] (Second Embodiment) Hereinafter, the same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted, and different parts will be described. In the second embodiment, the manufacturing process of the rotor is slightly different. As shown in FIG. 9, when the process up to step S7 is executed, steps S10 and S11 are executed without magnetizing the main magnet 2. Then, with the ring-shaped split resin molding portion 1 inserted on the inner peripheral side of the rotor frame 12, the main magnet 2 is magnetized by a magnetizing device (S13). Thereby, the rotor 13 is completed (S14). According to such a second embodiment, since the main magnet 2 is magnetized with the ring-shaped split resin molding portion 1 inserted in the rotor frame 12, the magnetic repulsive force and attractive force of the magnets 2 and 3 do not act during assembly, and assembly can be easily performed.

[0018] (Third and Fourth Embodiments) FIGS. 10 and 11 show the third and fourth embodiments, respectively, and illustrate other configuration examples of the split resin portion. In the third embodiment shown in FIG. 10, the thickness dimension of the auxiliary magnet 14 is made the same as that of the main magnet 2, and the split resin portion 15 is configured without providing a step as in the first embodiment, and is a configuration corresponding to the signal waveform of the magnetic sensor shown in FIG. 8.

[0019] In the fourth embodiment shown in FIG. 11, in the configuration of the third embodiment, the thickness of the auxiliary magnet 16 is made thinner than that of the main magnet 2 as in the first embodiment to form the split resin portion 16.

[0020] (Fifth Embodiment) FIG. 12 shows a fifth embodiment applied to an axial gap type permanent magnet motor 31. In this motor 31, a rotor 32 is located above in the figure, and a stator 33 is located below in the figure. The rotor yoke 34 shown in a transparent state in the figure is composed of a ring-shaped flat plate, and the main magnet 35 and the auxiliary magnet 36 are arranged on the lower surface side of the rotor yoke 34. The main magnet 35 is magnetically oriented in the upward direction from the bottom, that is, in the axial direction. The auxiliary magnet 36 is magnetically oriented in the circumferential direction as in the first embodiment and the like.

[0021] The radial length in the longitudinal direction of the main magnet 35 is set to be longer than the radial length of the auxiliary magnet 36. The radial ends of the main magnet 35 protrude outward beyond the outer edge of the rotor yoke 34. The radial end face of the auxiliary magnet 36 is positioned to be equal to the outer edge of the rotor yoke 34 or slightly inside the outer edge. That is, the tip faces of both magnets 35 and 36 are arranged so as to form steps, i.e., unevenness, in the circumferential direction. The magnets 35 and 36 are resin-molded by the same manufacturing method as in the first embodiment.

[0022] And the magnetic sensor 24 is supported by a support member (not shown) with a slight gap from the outer edge of the rotor yoke 34. Thus, when the rotor 32 rotates, the magnetic sensor 24 is positioned at a position where the recess in the above-described arrangement with uneven tip faces is engaged.

[0023] In this embodiment, by making the radial dimensions of the main magnet 35 and the auxiliary magnet 36 different, a step is provided on the outer peripheral side where the magnetic sensor 24 is arranged, and no step is provided on the central axis side. Alternatively, a structure having a step on the central axis side can also be achieved by making the radial dimensions of the main magnet 35 and the auxiliary magnet 36 equal. As described above, according to the fifth embodiment, the present invention can also be applied to the axial gap type permanent magnet motor 31.

[0024] (Other Embodiments) The split resin part is not limited to dividing the ring into six parts, and it may be divided into four parts, eight parts, etc. The dimensions of each part may be appropriately changed according to individual designs. Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0025] In the drawings, 1 is a split resin molding part, 2 is a main magnet, 3 is an auxiliary magnet, 4 is a resin, 12 is a rotor frame, 13 is a rotor, 14 is an auxiliary magnet, and 15 and 16 indicate split resin molding parts.

Claims

1. A rotor comprising a plurality of main magnets magnetically oriented in a first direction, and a plurality of auxiliary magnets magnetically oriented in a second direction orthogonal to the first direction and alternately arranged one by one between the main magnets; A stator; A magnetic sensor whose position is fixed with respect to the stator, and having, The first direction is a direction in which the magnetic sensor is located at its extension end, In the rotor, one end of the main magnet in the direction facing the stator is engaged with a position facing the magnetic sensor, and one end of the auxiliary magnet in the direction facing the stator is arranged so as not to engage with the position. A permanent magnet motor.

2. The permanent magnet motor according to claim 1, wherein the radial thickness of the auxiliary magnet is set to be thinner than that of the main magnet.

3. The permanent magnet motor according to claim 1, wherein the main magnet and the auxiliary magnet are arranged so as to provide a step on the end face side facing the magnetic sensor.

4. It is a radial gap type in which the longitudinal directions of the main magnet and the auxiliary magnet coincide with the axial direction, The permanent magnet motor according to claim 1, wherein one end face in the axial direction of the auxiliary magnet is arranged in a state recessed in the axial direction from one end face in the axial direction of the main magnet.

5. It is an axial gap type in which the longitudinal directions of the main magnet and the auxiliary magnet coincide with the radial direction, The permanent magnet motor according to claim 1, wherein one end face in the radial direction of the auxiliary magnet is arranged in a state recessed in the radial direction from one end face in the radial direction of the main magnet.

6. The permanent magnet motor according to any one of claims 1 to 5, wherein the rotor has a structure in which a plurality of divided resin molded parts resin molded in an arc shape with the circumference divided into a plurality are connected in a circumferential shape.

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