Motor component and motor

Abstract

A motor component comprising an insulating composite member comprising a soft magnetic material and a non-magnetic ceramic.

Description

Motor parts and motors

[0001] The present invention relates to a motor component and a motor.

[0002] BACKGROUND ART Motor components used in motors have been known for some time (for example, see Patent Documents 1 and 2).

[0003] JP 2016-40996 A International Publication No. 2018 / 147052

[0004] However, even with the prior art such as Patent Documents 1 and 2, there is still room for improvement in the technology for improving motor efficiency in motor components.

[0005] An object of the present invention is to provide a technology for improving motor efficiency in motor components.

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following aspects.

[0007] (1) According to one aspect of the present invention, there is provided a motor component for use in a motor, the motor component comprising a composite member that includes a soft magnetic material and a non-magnetic ceramic, and that has insulating properties.

[0008] According to this configuration, the motor component used in the motor includes a composite material that contains a soft magnetic material and a non-magnetic ceramic and has insulating properties. By adjusting the combination of the soft magnetic material and the non-magnetic ceramic contained in the composite material, such a composite material can reduce leakage magnetic flux in the motor while maintaining insulating properties, thereby improving motor efficiency.

[0009] (2) In the motor component of the above aspect, the composite member may have a soft magnetic portion made of a soft magnetic material and a non-magnetic portion made of a non-magnetic ceramic, the non-magnetic portion having insulating properties and covering at least a portion of the soft magnetic portion. According to this configuration, the soft magnetic portion made of the soft magnetic material is at least partially covered by the non-magnetic portion made of the non-magnetic ceramic, which has insulating properties. This makes it difficult for a conductive path to be formed through the soft magnetic portion, thereby further improving motor efficiency.

[0010] (3) In the motor component of the above embodiment, the soft magnetic portion may have a particle shape, a plate shape, or a columnar shape. According to this configuration, the soft magnetic portion of the composite member has a particle shape, a plate shape, or a columnar shape. Because the composite member can include soft magnetic portions formed of a soft magnetic material in these shapes, there is a high degree of freedom in the magnetic design to reduce leakage magnetic flux in the motor. Therefore, motor efficiency can be further improved.

[0011] (4) According to another aspect of the present invention, there is provided a motor. This motor includes the motor component described above. With this configuration, the motor component included in the motor can reduce leakage magnetic flux in the motor while maintaining insulation, resulting in a motor with improved motor efficiency.

[0012] The present invention can be realized in various forms, such as a method for manufacturing motor components, an apparatus equipped with motor components, a method for manufacturing a motor or an apparatus equipped with motor components, or a computer program that causes a computer to execute the manufacture of motor components.

[0013] 1 is a cross-sectional view of a motor including the motor component of the first embodiment. FIG. 1 is a cross-sectional view taken along line A-A in FIG. 1. FIG. 2 is an enlarged view of part B in FIG. 2. FIG. 3 is a cross-sectional view taken along line C-C in FIG. 3. FIG. 4 is a cross-sectional view illustrating a first modified example of a rotor core portion of the first embodiment. FIG. 5 is a cross-sectional view illustrating a second modified example of a rotor core portion of the first embodiment. FIG. 6 is a cross-sectional view illustrating a first modified example of a stator core portion of the first embodiment. FIG. 7 is a cross-sectional view illustrating a second modified example of a stator core portion of the first embodiment. FIG. 8 is a cross-sectional view illustrating a third modified example of a stator core portion of the first embodiment. FIG. 9 is a cross-sectional view illustrating a fourth modified example of a stator core portion of the first embodiment. FIG. 10 is a first view illustrating an evaluation result of the motor component of the first embodiment. FIG. 11 is a second view illustrating an evaluation result of the motor component of the first embodiment. FIG. 12 is a cross-sectional view of a motor of a comparative example. FIG. 13 is a cross-sectional view illustrating a first modified example of the motor of the first embodiment. FIG. 14 is a cross-sectional view illustrating a second modified example of the motor of the first embodiment.

[0014] 1 is a cross-sectional view of a motor including motor components according to a first embodiment. A rotor core 110 and a stator core 210, which are "motor components" according to this embodiment, are components used in a motor 1 that outputs rotational torque when power is supplied. The motor 1 includes a rotor 10 having the rotor core 110, a stator 20 having the stator core 210, and a motor case 30.

[0015] The rotor 10 includes a rotor core 110, magnets 120, and a shaft 130. The rotor core 110 of this embodiment is a composite member containing a soft magnetic material and a non-magnetic ceramic, and has insulating properties. In this embodiment, the rotor core 110 and the shaft 130 are integrally formed. For convenience, the rotor core 110 and the shaft 130 are referred to as a rotor member 100. The rotor 10 is provided in the motor 1 so as to be rotatable about a central axis C1 of the motor 1 as a rotation axis.

[0016] The rotor core 110 has a generally cylindrical shape and includes a soft magnetic portion 111 made of a soft magnetic material and a non-magnetic portion 112 made of a non-magnetic ceramic. The non-magnetic portion 112 is insulating and is formed to cover a portion of the soft magnetic portion 111.

[0017] FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1 , perpendicular to the central axis C1 of the motor 1. As shown in FIG. 2 , the rotor core 110 of this embodiment has multiple soft magnetic portions 111. The soft magnetic portions 111 of this embodiment are formed of ferrite. Each soft magnetic portion 111 has a substantially cylindrical shape and is disposed inside the rotor core 110 so that its longitudinal direction is aligned with the central axis C1 of the motor 1. Details of the positions of the multiple soft magnetic portions 111 inside the rotor core 110 will be described later. Note that the material forming the soft magnetic portions 111 is not limited to ferrite, and may be any soft magnetic material such as a soft magnetic metal or soft magnetic ceramic. The soft magnetic portions 111 may be, for example, nanocrystalline, amorphous, or pure iron.

[0018] The non-magnetic portion 112 has a generally cylindrical shape and is the same size as the rotor core portion 110. The non-magnetic portion 112 includes a retaining portion 112a that retains each of the soft magnetic portions 111 and a retaining portion 112b that retains a magnet 120 (described later) (see FIG. 1). The retaining portion 112a is a hole into which the soft magnetic portion 111 can be inserted, and the retaining portion 112b is a hole into which the magnet 120 can be inserted. The non-magnetic portion 112 is formed of ceramics containing silicon nitride and titanium nitride. Note that the material for the non-magnetic portion 112 is not limited to ceramics containing silicon nitride and titanium nitride, and may be any non-magnetic ceramic. The non-magnetic portion 112 may be, for example, aluminum nitride, ceramics containing alumina and zirconia, or ceramics containing zirconia and titanium nitride.

[0019] The magnets 120 are held by holding portions 112b of the non-magnetic portion 112 of the rotor core portion 110. As shown in Fig. 2, the motor 1 of this embodiment is a so-called IPM motor in which 16 magnets 120 are mounted inside the rotor core portion 110. The magnets 120 may be fixed to the non-magnetic portion 112 with an adhesive (resin), or may be fixed directly to the non-magnetic portion 112 (for example, by welding) without using an adhesive.

[0020] The rotor 10 of this embodiment includes eight magnet pairs P120, each consisting of two plate-shaped magnets 120. In each magnet pair P120, the two magnets 120 are arranged in a generally V-shape that opens outward from the motor 1, as shown in FIG. 2 . In the motor 1 of this embodiment, eight magnet pairs P120 are arranged to surround the central axis C1 of the motor 1. Among the eight magnet pairs P120, one magnet pair P120A, consisting of two magnets 120a and 120b, has a north pole on the outer side of the motor 1, and a south pole on the inner side of the motor 1, for example. Furthermore, in magnet pairs P120B and P121C adjacent to magnet pair P120A, the magnets 120c and 120d have a south pole on the outer side of the motor 1, and a north pole on the inner side of the motor 1, for example.

[0021] In this embodiment, among the multiple soft magnetic portions 111 included in the rotor core portion 110, the soft magnetic portion 111a is disposed between adjacent magnet pairs P120 on the inside of the eight magnet pairs P120 arranged to surround the central axis C1 of the motor 1. Among the multiple soft magnetic portions 111 included in the rotor core portion 110, the soft magnetic portion 111b is disposed between the two magnets 120 included in one magnet pair P120 on the outside of the eight magnet pairs P120 arranged to surround the central axis C1 of the motor 1. In the rotor core portion 110 of this embodiment, the shape, number, and position of the soft magnetic portions 111 formed of a soft magnetic material and disposed inside the nonmagnetic portion 112 formed of nonmagnetic ceramics can be freely changed, thereby improving the degree of freedom in magnetic design to reduce leakage magnetic flux in the motor 1. Note that the soft magnetic portion 111 may be fixed to the nonmagnetic portion 112 with an adhesive (resin) or may be directly fixed to the nonmagnetic portion 112 (e.g., by welding) without using an adhesive. Modified examples of the rotor core portion of this embodiment will be described later.

[0022] The shaft portion 130 has two shaft portions 131 and 132. Each of the two shaft portions 131 and 132 is formed so as to protrude from each of two end faces 113 and 114 of the rotor core portion 110, which has a substantially cylindrical shape (see FIG. 1 ). Each of the shaft portions 131 and 132 has a substantially rod shape with its longitudinal direction aligned with the central axis C1 of the motor 1. The outer diameter of each of the shaft portions 131 and 132 is smaller than the outer diameter of the rotor core portion 110. The end of each of the shaft portions 131 and 132 opposite to the end connected to the rotor core portion 110 is exposed to the outside of the motor case 30.

[0023] The stator 20 has a stator core portion 210 and a winding 220 (see FIG. 1 ). The stator 20 is disposed outside the rotor core portion 110 and is fixed to the motor case 30 (described later) inside the motor case 30.

[0024] The stator core 210 is formed in a generally cylindrical shape, i.e., a shape excluding the central portion of a cylinder. The stator core 210 has multiple protrusions 211 and an outer circumferential portion 212 (see FIG. 2). The outer circumferential portion 212 has a generally cylindrical shape, with its outer portion fixed to the motor case 30 and its inner portion supporting the multiple protrusions 211. The windings 220 are conductor wires coated with an insulator and wound around each of the multiple protrusions 211. When electricity supplied from outside the motor 1 flows through the windings 220, a magnetic field is generated.

[0025] FIG. 3 is an enlarged view of portion B in FIG. 2 , and is an enlarged cross-sectional view including one of the protrusions 211 of the stator core 210. The stator core 210 has a soft magnetic portion 210a made of a soft magnetic material and a non-magnetic portion 210b made of a non-magnetic ceramic. Specifically, as shown in FIG. 3 , the interiors (soft magnetic portion 210a) of the protrusion 211 and the outer peripheral portion 212 are made of a soft magnetic material, while the surface portions (non-magnetic portion 210b) of the protrusion 211 and the outer peripheral portion 212 are made of a non-magnetic ceramic. More specifically, a non-magnetic portion 210b is formed on each of the outer surface 212a of the outer peripheral portion 212 that contacts the motor case 30 and the surface 211a of the protrusion 211 that contacts the winding 220. On the other hand, the non-magnetic portion 210b is not formed on the surface 211b at the tip of the protrusion 211. In the stator core portion 210 of this embodiment, the soft magnetic portion 210a is made of pure iron, and the non-magnetic portion 210b is made of ceramics consisting of alumina and zirconia.

[0026] 4 is a cross-sectional view taken along line CC in FIG. 3, and is a schematic cross-sectional view of the protrusion 211 in a direction parallel to the central axis C1 of the motor 1. As shown in FIG. 4, the protrusion 211 has a substantially rectangular cross-sectional shape, and each of its four corners 211c is formed to have an R-shape. As described above, the protrusion 211 of the stator core 210 of this embodiment has a soft magnetic portion 210a provided therein. The non-magnetic portion 210b of the protrusion 211 is formed so as to cover at least a portion of the soft magnetic portion 210a, specifically, the surface of the portion of the protrusion 211 around which the winding 220 (shown by the two-dot chain line in FIG. 4) is wound. As a result, the insulation resistance value of the protrusion 211 is 1×10 －６ Since the resistance is Ω cm or more, it is difficult for a conductive path to be generated inside the protrusion 211. Therefore, by adjusting the combination of the soft magnetic portion 210a made of a soft magnetic material and the non-magnetic portion 210b made of a non-magnetic ceramic, the stator core 210 of this embodiment can maintain insulation while reducing leakage magnetic flux in the motor 1. Modifications of the stator core of this embodiment will be described later.

[0027] The motor case 30 is a hollow member that houses the rotor 10 and the stator 20. Two bearings 310, 320 are provided in the motor case 30. The bearings 310, 320 are provided on two opposing bracket portions 301, 302 of the motor case 30. One of the two shaft portions 131, 132, the shaft portion 131, is inserted through the bearing 310, and the other of the two shaft portions 131, 132, the shaft portion 132, is inserted through the bearing 320. As a result, the rotor 10 is rotatably supported by the motor case 30.

[0028] Next, an example of a manufacturing method for the rotor 10 and stator 20 of this embodiment will be described. In the manufacturing method for the rotor 10, first, predetermined amounts of silicon nitride particles, titanium nitride particles, and a sintering aid are weighed as main raw materials. Next, the weighed materials are placed in a ball mill together with ethanol and milled and mixed for a predetermined time to prepare a slurry. Next, the prepared slurry is extruded to form an extruded body having a generally cylindrical shape. Next, the extruded body is processed to form a portion that will become the shaft portion 130, portions that will become the retaining portions 112a and 112b, and the like, to prepare a processed body having a shape that combines the nonmagnetic portion 112 of the rotor core 110 with the shaft portion 130. Next, the processed body is fired by heating under predetermined conditions to prepare a fired body. Next, the soft magnetic portion 111 is fixed to the retaining portion 112a formed in the fired body to prepare the rotor member 100. Finally, the magnets 120 are fixed to the holding portions 112b of the rotor member 100 to complete the rotor 10. Note that the manufacturing method of the rotor member 100 and the rotor 10 shown here is an example, and the manufacturing method is not limited to this.

[0029] In the manufacturing method of the stator 20, first, multiple plate-shaped members made of pure iron are stacked to form the soft magnetic portion 210a. Next, a slurry containing alumina particles, zirconia particles, and a sintering aid is applied to the surface of the soft magnetic portion 210a, specifically, the outer surface of the portion that will become the outer periphery 212 of the stator core portion 210 and the surface of the portion that will become the protrusion 211 and contact the winding 220, respectively, to shape the portion that will become the nonmagnetic portion 210b. Next, the soft magnetic portion 210a to which the slurry has been applied is fired by heating under predetermined conditions, thereby producing the stator core portion 210. Finally, the winding 220 is wound around each of the multiple protrusions 211 of the manufactured stator core portion 210, thereby producing the stator 20. Note that the manufacturing method of the stator core portion 210 and the stator 20 shown here is merely an example and is not limited to this manufacturing method.

[0030] Figure 5 is a cross-sectional view illustrating a first modified example of the rotor core portion of the first embodiment. Figure 5 is a cross-sectional view corresponding to Figure 2, showing a cross-sectional view of a motor 2 including a rotor 40 having a structure different from that of the rotor 10 shown in Figure 2. The motor 2 includes the rotor 40, a stator 20 having a stator core portion 210, and a motor case 30. The rotor 40 includes a rotor core portion 410, a magnet 120, and a shaft portion 130. The rotor core portion 410 of this embodiment is a composite member including a soft magnetic material and a non-magnetic ceramic, and has insulating properties.

[0031] The rotor core 410 has a plurality of soft magnetic portions 411 made of a soft magnetic material and a non-magnetic portion 412 made of a non-magnetic ceramic. The non-magnetic portion 412 has insulating properties and is formed so as to cover at least a portion of the soft magnetic portion 411.

[0032] Each of the soft magnetic portions 411 is made of ferrite. The soft magnetic portions 411 have a generally flat plate shape and are disposed inside the rotor core portion 410 with their longitudinal direction aligned with the central axis C2 of the motor 2. As shown in FIG. 5 , each of the soft magnetic portions 411 is disposed between adjacent magnet pairs P120 on the inner side of the eight magnet pairs P120. In this embodiment, the thickness of the soft magnetic portion 411 shown in FIG. 5 is approximately 1 mm. However, the thickness of the soft magnetic portion 411 is not limited to this and may be approximately several tens of micrometers to several hundreds of micrometers, and may be a so-called foil-shaped soft magnetic portion 411.

[0033] The non-magnetic portion 412 has a substantially cylindrical shape and is the same size as the rotor core portion 410. The non-magnetic portion 412 holds each of the soft magnetic portions 411 and the magnet 120. The non-magnetic portion 412 is made of silicon nitride and titanium nitride. The manufacturing method of the rotor core portion 410 is the same as the manufacturing method of the rotor core portion 110, which is included in the manufacturing method of the rotor 10.

[0034] Figure 6 is a cross-sectional view illustrating a second modified example of the rotor core portion of the first embodiment. Figure 6 is a cross-sectional view corresponding to the cross-sectional view of the motor 1 shown in Figure 2, and shows a cross-sectional view of a motor 3 including a rotor 50 having a structure different from that of the rotor 10 shown in Figure 2. The motor 3 includes the rotor 50, a stator 20 having a stator core portion 210, and a motor case 30. The rotor 50 includes a rotor core portion 510, a magnet 120, and a shaft portion 130. The rotor core portion 510 of this embodiment is a composite member including a soft magnetic material and a non-magnetic ceramic, and has insulating properties.

[0035] The rotor core 510 has a plurality of soft magnetic portions 511 made of a soft magnetic material and a non-magnetic portion 512 made of a non-magnetic ceramic. The non-magnetic portion 512 has insulating properties and is formed to cover at least a portion of the soft magnetic portion 511.

[0036] Each of the soft magnetic portions 511 is made of ferrite. The cross section of the soft magnetic portion 511 shown in FIG. 6 has a generally U-shaped plate shape, and the soft magnetic portion 511 is disposed inside the rotor core portion 510 with its longitudinal direction aligned with the central axis C3 of the motor 3. Of the soft magnetic portions 511, the soft magnetic portion 511a is disposed inside the eight magnet pairs P120 so as to straddle the two magnets 120 of one magnet pair P120. Of the soft magnetic portions 511, the soft magnetic portion 511b is disposed inside the eight magnet pairs P120 between adjacent magnet pairs P120. Of the soft magnetic portions 511, the soft magnetic portion 511c is disposed outside the eight magnet pairs P120 between the two magnets 120 of one magnet pair P120. The shape of the soft magnetic portion 511 is not limited to a generally U-shape, and various shapes can be selected.

[0037] The non-magnetic portion 512 has a substantially cylindrical shape and is the same size as the rotor core portion 510. The non-magnetic portion 512 holds each of the soft magnetic portions 511 and the magnet 120. The non-magnetic portion 512 is made of silicon nitride and titanium nitride. The manufacturing method of the rotor core portion 510 is the same as the manufacturing method of the rotor core portion 110, which is included in the manufacturing method of the rotor 10.

[0038] The rotor cores 410 and 510 of the motors 2 and 3 are made of insulating composite materials containing soft magnetic material and non-magnetic ceramics. By adjusting the combination of the soft magnetic material and non-magnetic ceramics contained in the composite material in the rotor cores 410 and 510, the leakage magnetic flux in the motors 2 and 3 can be reduced while maintaining insulation.

[0039] Figure 7 is a cross-sectional view illustrating a first modified example of the stator core portion of this embodiment. Figure 7 is a cross-sectional view corresponding to Figure 3, and shows a cross-sectional view of a motor 4 including a stator 60 having a structure different from that of the stator 20 shown in Figure 3. The motor 4 includes a rotor 10, a stator 60, and a motor case 30. The stator 60 has a stator core portion 610 and a winding 220. The stator 60 is disposed outside the rotor core portion 110 and is fixed to the motor case 30 on the inside of the motor case 30.

[0040] The stator core 610 is formed to have a substantially cylindrical shape. The stator core 610 has a plurality of protrusions 611 and an outer circumferential portion 612. The outer circumferential portion 612 has a substantially cylindrical shape, and an outer portion thereof is fixed to the motor case 30, while an inner portion thereof supports the plurality of protrusions 611. The windings 220 are wound around each of the plurality of protrusions 611.

[0041] The stator core 610 has a soft magnetic portion 610a made of a soft magnetic material and a non-magnetic portion 610b made of a non-magnetic ceramic. In the stator core 610, the soft magnetic portion 610a is, for example, pure iron having a particle shape with a particle size of 30 μm, and is dispersed within the non-magnetic portion 610b made of insulating silicon nitride. In the stator core 610, at least a portion of the multiple soft magnetic portions 610a is completely covered by the non-magnetic portion 610b, forming a composite of soft magnetic metal particles and non-magnetic ceramic. Note that, for convenience of explanation, in FIG. 7, the soft magnetic portion 610a is shown larger than the non-magnetic portion 610b.

[0042] Here, a method for manufacturing the stator core 610 will be described. To manufacture the stator core 610, first, predetermined amounts of pure iron particles for the soft magnetic portion 610a, silicon nitride particles for the nonmagnetic portion 610b, and a sintering aid are weighed out. Next, the weighed materials are placed in a ball mill together with ethanol and milled and mixed for a predetermined time to produce a slurry. The produced slurry is then extruded to form an extruded body having a substantially cylindrical shape. Next, the extruded body is processed to form portions where the windings 220 to be wound around the protrusions 611 are located, producing a processed body. Finally, the processed body is fired by heating under predetermined conditions to produce the stator core 610. The stator 60 is produced by winding the windings 220 around each of the multiple protrusions 611 of the produced stator core 610. Note that the manufacturing method for the stator core 610 and the stator 60 shown here is merely an example and is not limited to this manufacturing method.

[0043] Figure 8 is a cross-sectional view illustrating a second modified example of the stator core portion of this embodiment. Figure 8 is a cross-sectional view corresponding to Figure 3, and shows a cross-sectional view of a motor 5 including a stator 70 having a structure different from that of the stator 20 shown in Figure 3. The motor 5 includes a rotor 10, a stator 70, and a motor case 30. The stator 70 has a stator core portion 710 and a winding 220. The stator 70 is disposed outside the rotor core portion 110 and is fixed to the motor case 30 on the inside of the motor case 30.

[0044] The stator core portion 710 is formed to have a substantially cylindrical shape. The stator core portion 710 has a plurality of protrusions 711 and an outer peripheral portion 712. The outer peripheral portion 712 has a substantially cylindrical shape, and while an outer portion thereof is fixed to the motor case 30, an inner portion thereof supports the plurality of protrusions 711. The windings 220 are wound around each of the plurality of protrusions 711.

[0045] The stator core 710 has a soft magnetic portion 710a made of a soft magnetic material and a non-magnetic portion 710b made of a non-magnetic ceramic. In the stator core 710, the soft magnetic portion 710a is made of pure iron and has a columnar shape with a substantially rectangular cross section, as shown in FIG. 8 . The soft magnetic portion 710a is arranged so that its longitudinal direction is aligned with the center of rotation of the motor 5. In the stator core 710, the soft magnetic portion 710a is partially covered by the non-magnetic portion 710b, forming a composite of the soft magnetic metal and the non-magnetic ceramic. Note that the size relationship between the soft magnetic portion 710a and the non-magnetic portion 710b shown in FIG. 8 is not limited to this.

[0046] Here, a method for manufacturing the stator core portion 710 will be described. The stator core portion 710 can be manufactured by a method similar to the method for manufacturing the rotor core portion 110, which is included in the manufacturing method of the rotor 10 of this embodiment. Specifically, first, predetermined amounts of nonmagnetic ceramics as main raw materials and a sintering aid are weighed. Next, the weighed materials are charged into a ball mill together with ethanol and pulverized and mixed for a predetermined time to prepare a slurry. Next, the prepared slurry is extrusion-molded to form an extruded body having a substantially cylindrical shape. Next, spaces for winding the winding 220, holes for inserting the soft magnetic portions 710a, and the like are machined into the extruded body to prepare a machined body. Next, the machined body is fired by heating under predetermined conditions, and the soft magnetic portions 710a are inserted and fixed into the holes to prepare the stator core portion 710. The stator 70 is manufactured by winding the winding 220 into the spaces of the manufactured stator core portion 710. The manufacturing method of the stator core portion 710 and the stator 70 shown here is an example, and the manufacturing method is not limited to this.

[0047] Figure 9 is a cross-sectional view illustrating a third modified example of the stator core portion of this embodiment. Figure 9 is a cross-sectional view corresponding to Figure 3, showing a motor 6 equipped with a stator 80 having a structure different from that of the stator 20 shown in Figure 3. The motor 6 includes a rotor 10, a stator 80, and a motor case 30. The stator 80 has a stator core portion 810 and a winding 220. The stator 80 is disposed outside the rotor core portion 110 and is fixed to the motor case 30 on the inside of the motor case 30.

[0048] The stator core portion 810 is formed to have a substantially cylindrical shape. The stator core portion 810 has a plurality of protrusions 811 and an outer circumferential portion 812. The outer circumferential portion 812 has a substantially cylindrical shape, and an outer portion thereof is fixed to the motor case 30, while an inner portion thereof supports the plurality of protrusions 811. The windings 220 are conductor wires coated with an insulator, and are wound around each of the plurality of protrusions 811.

[0049] The stator core 810 includes a soft magnetic portion 810a made of a soft magnetic material and a nonmagnetic portion 810b made of a nonmagnetic ceramic. In the stator core 810, the soft magnetic portion 810a is a flat plate of pure iron with a substantially rectangular cross section, as shown in FIG. 9 . The soft magnetic portion 810a is arranged such that its longitudinal direction is aligned with the center of rotation of the motor 6. In this embodiment, three soft magnetic portions 810a are arranged side by side along the circumferential direction of the motor 6. In the stator core 810, the soft magnetic portion 810a is partially covered by the nonmagnetic portion 810b, resulting in a composite of soft magnetic metal and nonmagnetic ceramic. The manufacturing method of the stator core 810 is similar to the manufacturing method of the stator core 710 described above, except for the shape and number of holes formed in the extrusion molded body into which the soft magnetic portion 810a is inserted. Note that the size relationship between the soft magnetic portion 810a and the nonmagnetic portion 810b shown in FIG. 9 is not limited to this.

[0050] Figure 10 is a cross-sectional view illustrating a fourth modified example of the stator core portion of this embodiment. Figure 10 is a cross-sectional view corresponding to Figure 3 and shows a cross-sectional view of a motor 7 including a stator 90 having a structure different from that of the stator 20 shown in Figure 3. The motor 7 includes a rotor 10, a stator 90, and a motor case 30. The stator 90 has a stator core portion 910 and a winding 220. The stator 90 is disposed outside the rotor core portion 110 and is fixed to the motor case 30 on the inside of the motor case 30.

[0051] The stator core portion 910 is formed to have a substantially cylindrical shape. The stator core portion 910 has a plurality of protrusions 911 and an outer circumferential portion 912. The outer circumferential portion 912 has a substantially cylindrical shape, and an outer portion thereof is fixed to the motor case 30, while an inner portion thereof supports the plurality of protrusions 911. The windings 220 are wound around each of the plurality of protrusions 911.

[0052] The stator core 910 includes a soft magnetic portion 910a made of a soft magnetic material and a nonmagnetic portion 910b made of a nonmagnetic ceramic. In the stator core 910, the soft magnetic portion 910a is a flat plate of pure iron with a substantially rectangular cross section, as shown in FIG. 10 . The soft magnetic portion 910a is arranged such that its longitudinal direction is aligned with the center of rotation of the motor 7. In this embodiment, three soft magnetic portions 910a are arranged side by side along the radial direction of the motor 7. In the stator core 910, the soft magnetic portion 910a is covered by the nonmagnetic portion 910b, resulting in a composite of soft magnetic metal and nonmagnetic ceramic. The manufacturing method of the stator core 910 is similar to the manufacturing method of the stator core 710 described above, except for the shape and number of holes formed in the extrusion molded body into which the soft magnetic portion 910a is inserted. Note that the size relationship between the soft magnetic portion 910a and the nonmagnetic portion 910b shown in FIG. 10 is not limited to this.

[0053] In the stator core portions 610, 710, 810, and 910 provided in the motors 4, 5, 6, and 7, the soft magnetic portions 610a, 710a, 810a, and 910a are covered with the nonmagnetic portions 610b, 710b, 810b, and 910b. As a result, even when the windings 220 are wound around the stator core portions 610, 710, 810, and 910, no conductive paths are formed inside the stator core portions 610, 710, 810, and 910, and insulation can be maintained. In this way, each of the stator core portions 610, 710, 810, and 910 is an insulating composite member that includes a soft magnetic material and a nonmagnetic ceramic. Thus, by adjusting the combination of the soft magnetic material and non-magnetic ceramics contained in the composite material in the stator core portions 610, 710, 810, and 910, it is possible to reduce leakage magnetic flux in the motors 4, 5, 6, and 7 while providing insulation.

[0054] Next, an evaluation test of the motor component of this embodiment will be described. In this evaluation test, motor components (hereinafter simply referred to as "samples") were fabricated for each of the rotor core and stator core used in an IPM motor, with different materials for the soft magnetic portions, different shapes of the soft magnetic portions, or different materials for the non-magnetic portions, and 13 types of samples were evaluated for "insulation," "strength," and "motor efficiency."

[0055] FIG. 11 is a first diagram illustrating the evaluation results of the motor component of this embodiment. In this evaluation test, seven types of samples were prepared as rotor core portions. Of the seven samples, Samples 1 to 5 were fabricated using a method similar to the manufacturing method of the rotor core portion 110 included in the manufacturing method of the rotor 10 of this embodiment. Sample 6 was fabricated using a method similar to the manufacturing method of the rotor core portion 110 included in the manufacturing method of the rotor 10 of this embodiment, excluding the machining process of the retaining portion 112a that holds the soft magnetic portion 111 and the fixing process of the soft magnetic portion 111. Sample 7 was fabricated by stacking multiple electromagnetic steel sheets. In this evaluation test, a motor including each of Samples 1 to 7 refers to a motor that combines a rotor including each of Samples 1 to 7 as a rotor core portion with a stator including a stator core portion made only of electromagnetic steel sheets.

[0056] FIG. 12 is a second diagram illustrating the evaluation results of the motor component of this embodiment. In this evaluation test, six types of samples were prepared as stator cores. Of the six samples, Samples 8 to 10 were manufactured using the same manufacturing method as the stator core 610, which is a method conforming to the manufacturing method of the rotor core 110 included in the manufacturing method of the rotor 10 of this embodiment. Specifically, to prepare the slurry used to mold the extrusion-molded body, particles formed from a soft magnetic material, particles formed from a nonmagnetic ceramic, and a sintering aid were used. Sample 11 was manufactured using a method conforming to the manufacturing method of the stator core 710. Sample 12 was manufactured using a method conforming to the manufacturing method of the stator core 810. Sample 13 was manufactured by extrusion molding a mixture of epoxy resin pellets and pure iron particles, which was heated and melted. In this evaluation test, a motor equipped with each of Samples 8 to 13 refers to a motor that combines a rotor having a rotor core portion made only of electromagnetic steel sheets and a stator having each of Samples 8 to 13 as a stator core portion.

[0057] Among the items shown in Figures 11 and 12, the "shape" of the soft magnetic portion indicates the shape of the soft magnetic portion that is at least partially covered by the non-magnetic portion. Regarding the "shape" of the soft magnetic portion of the rotor core portion shown in Figure 11, the sample described as "columnar shape" has a soft magnetic portion with the shape shown in Figure 2, and the sample described as "plate shape" has a soft magnetic portion with the shape shown in Figure 5. Regarding the "shape" of the soft magnetic portion of the stator core portion shown in Figure 12, the sample described as "particle shape" has a soft magnetic portion with the shape shown in Figure 7, the sample described as "columnar shape" has a soft magnetic portion with the shape shown in Figure 8, and the sample described as "plate shape" has a soft magnetic portion with the shape shown in Figure 9 or Figure 10.

[0058] FIG. 13 is a cross-sectional view of a comparative motor. In this evaluation test, the "motor efficiency" shown in FIGS. 11 and 12 indicates the results of a comparison with a comparative motor Mc (hereinafter simply referred to as the "comparative motor") equipped with a comparative rotor 10c and a comparative stator 20c. The comparative rotor 10c is a rotor equipped with a rotor core portion (sample 7 shown in FIG. 11) made only of electromagnetic steel sheets, and the comparative stator 20c is a stator equipped with a stator core portion made only of electromagnetic steel sheets. As shown in FIG. 13, the comparative rotor 10c is provided with multiple magnets 120, similar to the rotor 10 of this embodiment. As shown in FIG. 13, the comparative stator 20c is wound with a winding 220, similar to the stator 20 of this embodiment.

[0059] 11 and 12, the electrical resistance values ​​of Samples 1 to 13 were measured using the four-terminal method. The measured electrical resistance values ​​were classified into the following symbols, A and B. A: 1×10 －６ Ω・cm or more B: 1×10 －６ Less than Ω cm

[0060] "Strength" shown in Figures 11 and 12 indicates the durability of motor parts against centrifugal force and stress acting during rotation. "Strength" was measured by the following method. First, the rotation speed of motors equipped with each of Samples 1 to 13 was gradually increased, and the rotation speed at which the motor parts broke was measured. Next, the magnitude of the rotation speed was taken as "strength" and classified into the following symbols A, B, and C. A: The rotation speed at which the parts broke was 15,000 rpm or more. B: The rotation speed at which the parts broke was 10,000 rpm or more but less than 15,000 rpm. C: The rotation speed at which the parts broke was less than 10,000 rpm.

[0061] The "motor efficiency" shown in Figures 11 and 12 indicates the ratio of output to input in the motor. To measure "motor efficiency," first, the output of the motors equipped with each of Samples 1 to 13 and the motor of the comparative example was measured when rotated at a predetermined rotation speed. The degree of the magnitude of the output measured for the motors equipped with each of Samples 1 to 13 relative to the output measured for the motor of the comparative example was taken as "motor efficiency" and classified into the following symbols A, B, and C. A: There is a rotation speed at which the efficiency is improved by 2% or more compared to the motor of the comparative example. B: There is a rotation speed at which the efficiency is improved by 1% or more compared to the motor of the comparative example. C: About the same as the motor of the comparative example.

[0062] The results of the evaluation test on the rotor core portion shown in Figure 11 confirmed that, in terms of "insulation," Samples 1 to 6, which include a non-magnetic portion, are superior to Sample 7, which is formed from electromagnetic steel sheets. In terms of "motor efficiency," Samples 1 to 6, which are composite members including a soft magnetic material and a non-magnetic ceramic, are superior to Sample 6, which does not include a soft magnetic portion, and Sample 7, which is formed from electromagnetic steel sheets. Therefore, it became clear that by providing the rotor core portion with a composite member including a soft magnetic material and a non-magnetic ceramic, it is possible to improve motor efficiency while maintaining the insulation properties of the rotor core portion.

[0063] The results of the evaluation test on the stator core shown in Figure 12 confirmed that Samples 8 to 12, whose non-magnetic portions are made of non-magnetic ceramics, have similar insulation performance to Sample 13, whose non-magnetic portions are made of epoxy resin. Samples 8 to 12 were also found to be superior to Sample 13 in terms of strength and motor efficiency. Therefore, it became clear that providing the stator core with a composite member containing a soft magnetic material and non-magnetic ceramics can improve the strength and motor efficiency while maintaining the insulation properties of the stator core. Sample 13 received a "C" rating for motor efficiency because it has poor thermal conductivity and tends to accumulate heat.

[0064] According to the rotor core portion 110, 410, 510 of the present embodiment described above, the rotor core portion 110, 410, 510 is provided with an insulating composite material containing a soft magnetic material and a non-magnetic ceramic. By adjusting the combination of the soft magnetic material and the non-magnetic ceramic, the rotor core portion 110, 410, 510 can reduce leakage magnetic flux in the motor while maintaining insulation. This can improve the motor efficiency of each of the motors 1, 2, 3.

[0065] Furthermore, according to the stator core portions 210, 610, 710, 810, and 910 of the present embodiment, the stator core portions 210, 610, 710, 810, and 910 are made of a composite material containing a soft magnetic material and a non-magnetic ceramic, and have insulating properties. By adjusting the combination of the soft magnetic material and the non-magnetic ceramic, the stator core portions 210, 610, 710, 810, and 910 can reduce leakage flux in the motor while also providing insulating properties. This can improve the motor efficiency of each of the motors 1, 4, 5, 6, and 7.

[0066] Furthermore, in the stator core portions 210, 610, 710, 810, and 910 of this embodiment, the soft magnetic portions 210a, 610a, 710a, 810a, and 910a made of a soft magnetic material are at least partially covered by the nonmagnetic portions 210b, 610b, 710b, 810b, and 910b made of a nonmagnetic ceramic and therefore having insulating properties. This makes it difficult for a conductive path to be formed through the soft magnetic portions 210a, 610a, 710a, 810a, and 910a in the stator core portions 210, 610, 710, 810, and 910, thereby further improving the motor efficiency of each of the motors 1, 4, 5, 6, and 7.

[0067] Furthermore, in the rotor core 110 of this embodiment, the soft magnetic portion 111 has a columnar shape. In the rotor cores 410 and 510, the soft magnetic portions 411 and 511 have a plate shape. In the stator core 610, the soft magnetic portion 610a has a particle shape. In the stator core 710, the soft magnetic portion 710a has a columnar shape. In the stator cores 810 and 910, the soft magnetic portions 810a and 910a have a plate shape. As such, in each of the motors 1, 2, 3, 4, 5, 6, and 7, at least one of the rotor core and the stator core can include a soft magnetic portion formed of a soft magnetic material in these shapes, providing greater freedom in magnetic design to reduce leakage flux in the motor. This further improves the motor efficiency of the motors 1, 2, 3, 4, 5, 6, and 7.

[0068] Furthermore, the motors 1, 2, 3, 4, 5, 6, and 7 of this embodiment include a rotor core 110, 410, or 510, or a stator core 210, 610, 710, 810, or 910, which includes a composite member containing a soft magnetic material and a non-magnetic ceramic and has insulating properties. These motor components can reduce leakage magnetic flux in the motor while maintaining insulation properties. This improves the motor efficiency of the motors 1, 2, 3, 4, 5, 6, and 7.

[0069] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the present invention. For example, the following modifications are also possible.

[0070] [Variation 1] In the above-described embodiment, each of motors 1, 2, 3, 4, 5, 6, and 7 includes at least one of rotor core 110, 410, and 510 and stator core 210, 610, 710, 810, and 910 as a motor component including a composite member having insulating properties, including a soft magnetic material and a non-magnetic ceramic. However, the motor components constituting the motor are not limited to this. The shaft portion and the motor case may also be motor components having insulating properties, including a soft magnetic material and a non-magnetic ceramic.

[0071] [Modification 2] In the above-described embodiment, each of the rotor core portions 110, 410, and 510 includes a soft magnetic portion 111, 411, or 511 made of a soft magnetic material and a nonmagnetic portion 112, 412, or 512 made of a nonmagnetic ceramic. Each of the stator core portions 210, 610, 710, 810, and 910 includes a soft magnetic portion 210a, 610a, 710a, 810a, or 910a made of a soft magnetic material and a nonmagnetic portion 210b, 610b, 710b, 810b, or 910b made of a nonmagnetic ceramic. That is, in the above-described embodiment, the soft magnetic material content in the portion made of the soft magnetic material is approximately 100%, and the nonmagnetic ceramic content in the portion made of the nonmagnetic ceramic is approximately 100%, but the relationship between the soft magnetic material and the nonmagnetic ceramic contained in the motor component is not limited to this. For example, it may be made by mixing a soft magnetic material and a non-magnetic ceramic, so that the soft magnetic portion formed from the soft magnetic material and the non-magnetic portion formed from the non-magnetic ceramic cannot be clearly distinguished.

[0072] [Modification 3] In the above-described embodiment, the non-magnetic portion in the rotor core portion is formed to cover at least a portion of the soft magnetic portion. In the stator core portion, except for stator core portion 610 shown in Fig. 7, the non-magnetic portion is formed to cover at least a portion of the soft magnetic portion. In both the rotor core portion and the stator core portion, the non-magnetic portion may be formed to cover the entire soft magnetic portion.

[0073] [Modification 4] In the above-described embodiment, the soft magnetic portions of the rotor core are made of ferrite, and the soft magnetic portions of the stator core are made of pure iron. However, the material for the soft magnetic portions is not limited to this. They may be made of any soft magnetic material, such as a soft magnetic metal or soft magnetic ceramic, or may be a mixture of a soft magnetic metal and a soft magnetic ceramic.

[0074] [Variation 5] In the above-described embodiment, the soft magnetic portion 111 of the rotor core portion 110 has a columnar shape, and the soft magnetic portions 411, 511 of the rotor core portions 410, 510 have a plate shape. The soft magnetic portion 610a of the stator core portion 610 has a particle shape, the soft magnetic portion 710a of the stator core portion 710 has a columnar shape, and the soft magnetic portions 810a, 910a of the stator core portions 810, 910 have a plate shape. The shapes of the soft magnetic portions are not limited to these. By adjusting the position, shape, and number of the soft magnetic portions relative to the non-magnetic portions, it is possible to freely design the insulation properties as a "motor component" and the magnetic design within the motor.

[0075] [Variation 6] In the above-described embodiment, the rotor core portion 110 and the shaft portion 130 are described as being an integrally formed composite member. However, the relationship between the rotor core portion and the shaft portion is not limited to this. The rotor core portion and the shaft portion may be separate members.

[0076] Figure 14 is a cross-sectional view illustrating a first modified example of the motor of the first embodiment. The rotor 10 shown in Figure 14 includes a rotor core 110, a magnet 120, and two shaft portions 131 and 132. The shaft portion 131 is bonded to an end surface 113 of the rotor core 110 with an adhesive or the like. The shaft portion 132 is bonded to an end surface 114 of the rotor core 110 with an adhesive or the like. Even with this configuration, the rotor 10 of the motor 1 can improve motor efficiency if the rotor core 110 is an insulating composite member that includes a soft magnetic material and a non-magnetic ceramic.

[0077] Fig. 15 is a cross-sectional view illustrating a second modified example of the motor of the first embodiment. The rotor 10 shown in Fig. 15 includes a rotor core 110, a magnet 120, and one shaft 130. The longitudinal length of the shaft 130 is longer than the longitudinal length of the rotor core 110. The shaft 130 is inserted into a through hole 115 formed in the rotor core 110 and fixed to the rotor core 110. Even with this configuration, the rotor 10 of the motor 1 can improve motor efficiency if the rotor core 110 is an insulating composite member containing a soft magnetic material and a non-magnetic ceramic.

[0078] This aspect has been described above based on embodiments and modifications. However, the above-described embodiments are intended to facilitate understanding of this aspect and are not intended to limit this aspect. This aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in this aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0079] <Application Example 1> A motor component, comprising a composite member including a soft magnetic material and a non-magnetic ceramic, the composite member having insulating properties. <Application Example 2> The motor component according to Application Example 1, wherein the composite member has: a soft magnetic portion formed from a soft magnetic material; and a non-magnetic portion formed from a non-magnetic ceramic, the non-magnetic portion having insulating properties and covering at least a portion of the soft magnetic portion. <Application Example 3> The motor component according to Application Example 1 or Application Example 2, wherein the soft magnetic portion has a particle shape, a plate shape, or a columnar shape. <Application Example 4> A motor, comprising the motor component according to any one of Application Examples 1 to 3.

[0080] 1, 2, 3, 4, 5, 6, 7... Motor 110, 410, 510... Rotor core portion 210, 610, 710, 810, 910... Stator core portion 111, 210a, 411, 511, 610a, 710a, 810a, 910a... Soft magnetic portion 112, 210b, 412, 512, 610b, 710b, 810b, 910b... Non-magnetic portion

Claims

1. A motor component, comprising a composite member containing a soft magnetic material and a non-magnetic ceramic, the composite member having insulating properties.

2. A motor component according to claim 1, characterized in that the composite member has: a soft magnetic portion made of a soft magnetic material; and a non-magnetic portion made of a non-magnetic ceramic, which has insulating properties and covers at least a portion of the soft magnetic portion.

3. A motor component according to claim 2, characterized in that the soft magnetic portion has a particle shape, a plate shape, or a columnar shape.

4. A motor comprising the motor component according to claim 1 or 2.

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