Rotor

Abstract

To improve the output torque and the resistance to centrifugal force of an IMP motor.SOLUTION: A rotor core 21 is formed of a stainless steel magnet instead of electromagnetic steel sheet to increase the magnetomotive force. At the same time, ribs 231 to 236 that divide bonded magnets 221 to 226 of the rotor core, as well as the outer peripheral end portions of both the rotor core and the bonded magnets in the pole and interpole outer peripheral regions, are made of non-magnetic stainless steel. This configuration prevents magnetic flux leakage from the bonded magnets to the ribs, bridges and the like, thereby increasing the effective magnetic flux and improving torque. Also, the strength of the ribs and the resistance to centrifugal force are improved so that rapid rotations are enabled.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a rotor for an IPM motor. [Background technology]

[0002] The rotor described in Patent Document 1 includes a cylindrical rotor core, multiple magnet rows formed for each magnetic pole, and ribs. Each of the multiple magnet rows is formed in an arc shape with the same center point that opens toward the outside in the radial direction of the rotor core, and includes multiple bonded magnets. The ribs are arranged between adjacent bonded magnets in each of the multiple magnet rows.

[0003] The rotor described in Patent Document 2 includes a rotor core, two bonded magnet rows, and a rib. Each of the two bonded magnet rows is formed in an arc shape that opens outward in the radial direction of the rotor core. The rib is disposed between adjacent bonded magnets in each of the two bonded magnet rows. The one first rib of the first magnet row is narrower in width than each of the three second ribs of the second magnet row.

[0004] [Patent Document 1] JP 2017-192211 A [Patent Document 2] JP 2023-098697 A [Patent Document 3] JP 2023-087317 A [Patent Document 4] WO2022 / 004672 publication [Patent Document 5] JP 2023-13775 A [Patent Document 6] Patent No. 6868174 [Patent Document 7] Patent No. 7125686 Summary of the Invention [Problem to be solved by the invention]

[0005] The ribs described in Patent Document 1 reduce stress caused by centrifugal force when the rotor rotates, preventing damage to the rotor. By providing the ribs, the strength of the rotor is improved, but the magnetic flux entering the rotor from the outside flows through the ribs. This reduces the magnetic flux contributing to the reluctance torque, lowering the reluctance torque. This in turn reduces the efficiency of the motor to which the rotor is applied.

[0006] The rib described in Patent Document 2 ensures resistance to centrifugal force while suppressing a decrease in total torque. Although the flow of magnetic flux to the first rib is suppressed by narrowing the width of the first rib relative to the width of the second rib, the flow of magnetic flux still occurs.

[0007] Patent documents 3 to 5 describe a method of demagnetizing the ribs to prevent the flow of magnetic flux to the ribs. In all cases, alloy elements are added to the electromagnetic steel sheet and the material is modified by melting with a laser. In this method, the modified area is very uneven and the shape changes, so post-modification processing such as surface grinding and shape correction is complicated and not practical.

[0008] The present invention has been made in view of the above circumstances, and is directed to a rotor core made of magnetic steel sheet. The magnet is changed from a stainless steel magnet made of a two-phase structure of martensite and austenite (silicon steel plate) to a stainless steel magnet made of a two-phase structure of martensite and austenite, and the magnetic steel plate is changed to a non-magnetic part in order to improve the strength of the rib and to block leakage of magnetic flux from the rib, that is, the rib is made non-magnetic stainless steel by making it non-magnetic, and the purpose is to improve the torque. At the same time, the non-magnetic modification is made possible by a simple process. [Means for solving the problem]

[0009] The inventors disclosed the invention of a stainless steel magnet in 2021 (Patent Document 6). Furthermore, as shown in Patent Document 7, based on the experience of changing the plate components of a magnetic denture attachment from a magnetic material to a stainless steel magnet and increasing the adhesive force by 50%, and noting that the resistivity of a stainless steel magnet is 72 μΩcm, more than twice that of the 32 μΩcm of the 3% silicon steel plate used as the magnetic material of an IPM motor, the inventors considered changing the magnetic material of the rotor of an IPM motor to a stainless steel magnet.

[0010] After much trial and error, it was discovered that by changing the structure of Cr-Ni stainless steel from 100% austenite to one with 80% or more martensite to create a semi-hard magnetic material, and by adopting a stainless steel magnet with a saturation magnetization of 12,000 to 16,000 G, a coercive force of 80 to 300 Oe, a residual magnetism Br of 6,000 to 8,000 G, and a maximum energy product of 0.2 to 4 MGOe at room temperature, and by making specific areas of the rotor core non-magnetic through modification, it was possible to increase the motor torque by 30% or more compared to a rotor whose main body material has not been modified to be non-magnetic with a magnetic material. Moreover, it was confirmed that by heating the non-magnetic areas to 900°C or more using a laser or high-frequency heating method, the austenite phase is restored and the magnet is modified to be non-magnetic without changing the shape of the outer periphery. The same effect was also confirmed in non-magnetic Fe-Mn alloys.

[0011] <Motor rotor> (1) The rotor of the motor of the present invention includes a rotor core, a plurality of permanent magnets formed for each magnetic pole, a rib, and a specific outer periphery. The rotor body material consisting of the rotor core, ribs and specific outer periphery is made by changing the structure of Cr-Ni stainless steel from 100% austenite to a structure containing 80% or more martensite to make a semi-hard magnetic material (0.1 to 1.0 mm thin plate), and after punching out the rotor core including multiple slots (magnet holes) to be filled with bonded magnets, the ribs and specific outer periphery are converted from martensite to austenite by high-frequency heating or local heating with a laser to form non-magnetic parts. This rotor core blank is laminated, and the bonded magnets are injected into the slots (magnet holes) through oriented magnetic field molding during the injection molding process, and the semi-hard magnetic material is saturated to become a permanent magnet to form a stainless steel magnet. As a result, the rotor core is made of a saturated magnetized stainless steel magnet, and the ribs and the specific outer peripheral portion are made of non-magnetic stainless steel that has been modified to be non-magnetic.

[0012] Here, the rib refers to a portion that is arranged between the slots formed by dividing the slot into multiple parts to prevent a decrease in strength of the rotor core due to the formation of a roughly U-shaped (arc-shaped) slot (a magnet hole in which the bonded magnet is molded integrally) (Fig. 5: 1310, 1320, Fig. 14: 6310-6340). That is, in one magnet row (called a single-layer type) or in each of multiple magnet rows (called a multi-layer type), a rib is arranged between adjacent bonded magnets. The specific outer periphery is A) Magnet end regions (1410, 1420 in Fig. 5, 6310 to 6340 in Fig. 14) consisting of connection parts from the outer peripheral ends of the bonded magnets (permanent magnets) to the outer peripheral ends of the rotor core, a) In the single-layer type, a magnet end outer region consisting of one magnet end region (1410 in Fig. 5) consisting of a connection portion extending from the outer peripheral end of one permanent magnet to the outer peripheral end of the rotor core, another magnet end region (1420 in Fig. 5) consisting of a portion extending from the outer peripheral end of the permanent magnet of another adjacent magnetic pole to the outer peripheral end of the rotor core, and a connecting portion (1510 in Fig. 5) connecting the one magnet end region to the other magnet end region; c) In the multi-layer type, the magnet end regions of all magnet rows, which are made up of connecting parts that run from the outer end of the permanent magnet in one magnetic pole to the outer end of the rotor core, and the inner and outer circumferential regions of the magnetic pole, which are made up of connecting parts that connect the magnet end regions of all magnet rows (35 in Figure 7, 57 in Figure 11), d) In the multi-layer type, the inner and outer regions of one magnetic pole, the inner and outer regions of another adjacent magnetic pole, and the outer region between the magnetic poles consisting of the connecting parts that connect the two (Figure 7: 46, Figure 11: 68), This refers collectively to the following four types:

[0013] Furthermore, compared to rotor cores made of conventional electromagnetic steel plates (silicon steel plates), rotor cores made of stainless steel magnets with a two-phase structure of martensite and austenite structures of Cr-Ni stainless steel have greater strength; furthermore, compared to ribs made of electromagnetic steel plates, the austenite structure of non-magnetically modified Cr-Ni stainless steel has greater strength and ductility, thereby enhancing the function of the ribs as strength components. In addition, for non-magnetic Fe-Mn alloys, a thin plate of semi-hard magnetic material is formed, and a rotor core blank having a plurality of magnet holes is stamped out. Using the same process as for the above-mentioned Cr-Ni stainless steel, a rotor core made of Fe-Mn alloy and the ribs and specific outer periphery are formed as non-magnetic portions.

[0014] Next, the configuration (arrangement) of the rotor core, the plurality of permanent magnets, the ribs and the specific outer periphery is as follows. The rotor core is made of Cr-Ni stainless steel magnets or Fe-Mn alloy magnets (referred to as stainless steel magnets), and the multiple permanent magnets are made of rare earth anisotropic bonded magnets (hereafter referred to as bonded magnets) built into the rotor core. The permanent magnets are arranged in an arc that extends along the rotation axis of the rotor core and opens outward in the radial direction of the rotor core when viewed from the direction of the rotation axis. The permanent magnets arranged in an arc shape are arranged in a single layer in the radial direction or in a multi-layered manner consisting of multiple layers.

[0015] Further, the plurality of permanent magnets have a first bonded magnet and a second bonded magnet adjacent to each other and are arranged in a slit extending along the rotation axis of the rotor core. Further, the rotor core has ribs arranged between the first bonded magnet and the second bonded magnet, and the ribs are made of a non-magnetic portion (non-magnetic stainless steel).

[0016] (2) The rotor of the present invention is composed of a stainless steel magnet portion that is efficiently magnetized in the same manner as the rare earth bonded magnet that is efficiently oriented, and contributes to the high performance of the motor. The reason is considered as follows.

[0017] First, in the rotor of the present invention, the ribs and the specific outer peripheral portion are non-magnetic portions (non-magnetic stainless steel). When a highly anisotropic orientation magnetic field is applied during injection molding into a slit with such non-magnetic portions, the highly anisotropic orientation magnetic field flows from the inner magnetic pole portion to the outer magnetic pole portion of the permanent magnet, and then continues to flow from the adjacent outer magnetic pole portion to the inner magnetic pole portion. However, if the non-magnetic portions of the ribs and the specific outer peripheral portion do not exist at this time, there will be a large leakage magnetic flux that directly flows from the inner magnetic pole to the outer magnetic pole of the permanent magnet powder that does not contribute to the orientation of the rare earth anisotropic magnet powder, and the highly anisotropic orientation magnetic field will be weakened. Conversely, if non-magnetic portions exist in the ribs and the specific outer peripheral portion, the leakage magnetic flux will be drastically reduced, and the highly anisotropic orientation magnetic field will be strengthened.

[0018] Conversely, the highly anisotropic orientation magnetic field applied to the rotor from the outside during injection molding becomes densely distributed in the slit of the rotor and the stainless steel magnet portion, and the effective magnetic flux contributing to the orientation of the rare earth anisotropic magnet powder is greatly increased. Therefore, the rare earth anisotropic bonded magnet according to the present invention is injection molded in a state where the highly anisotropic orientation magnetic field acts efficiently, resulting in a high orientation.

[0019] Also, depending on the strength of the polar anisotropic alignment magnetic field applied, the rare earth anisotropic bonded magnet is molded with a strong external magnetic field applied, so it exhibits high magnetic flux density after injection molding is completed, and magnetization after injection molding (post-magnetization) may not be necessary. This is effective in the case of rare earth anisotropic bonded magnets made of rare earth anisotropic magnet powder (for example, Nd-Fe-B magnet powder, etc.), which is a magnet powder that is difficult to align.

[0020] At the same time, the stainless steel magnet is also oriented and magnetized by the polar anisotropic oriented magnetic field that faces from the north pole to the south pole of the rare earth magnet, and the magnetic flux emitted from the rotor's magnetic poles increases by about 10% by changing the rotor's main body material from a magnetic material to a stainless steel magnet, in other words, by adding the magnetomotive force of the stainless steel magnet. This increases the motor torque by about 10%.

[0021] Needless to say, in the present invention, the permanent magnets contained in the rotor are bonded magnets, which has many advantages over embedding sintered magnets. For example, it is possible to reduce the use of rare and expensive rare earths. Also, when using sintered magnets, it is necessary to machine them into a tile shape, but this processing is unnecessary. In addition, no processing waste is generated, so rare and expensive rare earths are not wasted.

[0022] Furthermore, when using sintered magnets, there are problems such as breakage when inserting them into the slot, gaps between the magnet and the slot, and the need for adhesive to secure the magnet in the slot. Because the adhesive is non-magnetic, it creates gaps that increase magnetic resistance and reduce magnetic flux, which is problematic. However, bonded magnets, which are integrally molded within the slots, are naturally firmly and tightly fixed within the slots, and do not have the drawbacks of sintered magnets.

[0023] Furthermore, during the operation of the motor, large iron losses (eddy current losses and hysteresis losses) can occur in the sintered magnet. However, since each magnet particle of the bonded magnet is insulated by a binder resin that is an insulator, the resulting iron losses are extremely small. Particularly in the case of high-speed rotation, a significant effect is achieved. Therefore, a synchronous machine composed of a rotor incorporating the bonded magnet is suppressed in heat generation and becomes efficient. Also, since each magnet particle of the bonded magnet is coated with a binder resin, it has high oxidizability without the need for surface treatment or the like.

[0024] <Motor (Embedded Magnet Type (Inner-Embedded Magnet Type) Synchronous Machine)> The present invention can be understood not only as the above-described rotor but also as a motor (embedded magnet type (inner-embedded magnet type) synchronous machine) using the rotor. That is, the present invention may be a motor including the above-described rotor, a stator having coils evenly disposed around the outer periphery of the rotor, and a yoke that forms a magnetic circuit on the outer peripheral side of the coils. Note that, as appropriate, the yoke includes teeth within the coils.

[0025] Basically, a motor generates a rotational force (magnet torque) based on the attractive and repulsive forces generated between the magnetic poles formed by the permanent magnets provided on the rotor and the rotating magnetic field formed around the outer periphery of the rotor by the stator. However, in the case of a rotor that is an embedded magnet type (inner-embedded magnet type) synchronous machine, different from a surface magnet type synchronous machine, a difference between the inductance (Ld) generated in the magnetic poles and the inductance (Lq) generated between the magnetic poles is likely to occur. Therefore, a reluctance torque based on the attractive force often occurs in the rotor. Particularly when Ld < Lq, the reluctance torque and the magnet torque are in the same direction, and the output torque can increase.

[0026] Therefore, it is preferable that the rotor according to the present invention also has salient poles that adjust the shape, arrangement, etc. of the permanent magnets in the rotor to generate a reluctance torque that acts in the same direction as the magnet torque generated by the magnetic poles, for example, between adjacent magnetic poles formed by the permanent magnets.

[0027] <Manufacturing Method of Rotor> The rotor is manufactured according to the following steps. (1) Base material forming process A Cr-Ni non-magnetic steel sheet or an Fe-Mn non-magnetic steel sheet is cold-rolled into a thin sheet of 0.1 to 1.0 mm, and then subjected to a low-temperature cooling treatment at -70°C or below to form a base material of a semi-hard magnetic material consisting of 80% or more of a martensite structure. (2) Punching process A rotor core blank having a plurality of arc-shaped slots (magnet holes) is punched out from a base material made of a semi-hard magnetic material. (3)Heating process The rib sandwiched between the two slots and a specific outer peripheral portion between the outer peripheral edge of the rotor core and the magnet hole at the extreme end forming the arc are locally heated to 900 to 950°C using a heating device such as a laser to make them nonmagnetic, thereby forming a rotor preform consisting of a nonmagnetic portion. (4) Rotor blank forming process The process consists of an insulating coating forming process in which an insulating resin coating is applied to the rotor blank, and a lamination process in which the insulating coated rotor blanks are laminated. In the lamination process, the rotor plates are laminated so that the anisotropy of the stainless steel magnets is radially anisotropic. (5) Injection molding process Using a magnetic injection molding machine, rare earth anisotropic bonded magnets are polar anisotropically oriented magnetic field molded in a magnetic field of 0.5 to 2 T into the slots (magnet holes) of the laminated rotor blanks, and the magnet holes are filled. (6) Inspection process The magnetization distribution on the outer periphery of the rotor core is inspected to confirm that the rare earth bonded anisotropic magnets and stainless steel magnets are saturated with magnetization. Effect of the Invention

[0028] The present invention improves the strength of the ribs and blocks leakage of magnetic flux from the ribs, thereby improving the effective magnetic flux and torque. In addition, it blocks leakage of magnetic flux from the non-magnetic specific outer periphery, thereby improving the effective magnetic flux and torque. Furthermore, the ribs and the specific outer peripheral portion can be easily demagnetized by a simple process. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a front view of a motor according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of a rotor according to the first embodiment. [Diagram 3] FIG. 4 is a front view of a motor according to a second embodiment. [Figure 4] FIG. 11 is a cross-sectional view of a rotor according to a second embodiment. [Diagram 5] 1A and 1B are diagrams showing a portion of a rotor in the first and second embodiments, showing (a) a punched material with a slot formed therein, (b) a non-magnetic portion in the magnet end region, and (c) a non-magnetic portion in the outer peripheral region between the magnetic poles. [Figure 6] FIG. 11 is a front view of a motor according to a third embodiment. [Figure 7] FIG. 11 is a partially enlarged view of a rotor in a third embodiment. [Figure 8] FIG. 13 is a front view of a motor according to a fourth embodiment. [Figure 9] FIG. 11 is a partially enlarged view of a rotor in a fourth embodiment. [Figure 10] FIG. 13 is a front view of a motor according to a fifth embodiment. [Figure 11] FIG. 13 is a partially enlarged view of a rotor in a fifth embodiment. [Figure 12] FIG. 13 is a front view of a motor according to a sixth embodiment. [Figure 13] FIG. 13 is a partial enlarged view of a rotor in a sixth embodiment. [Figure 14] FIG. 13(a) is a diagram showing a punched material in which a slot is formed in a part of a rotor in the fifth and sixth embodiments. BEST MODE FOR CARRYING OUT THEINVENTION

[0030] [First embodiment] The first embodiment of the rotor of the IPM motor of the present invention is as follows: A rotor for an IPM motor, comprising: a rotor core made of stainless steel magnets and having an even number of slots each having an air gap arranged symmetrically around a central axis of rotation; ribs provided between the slots; and an even number of permanent magnets formed in the slots, The rotor core is made of Cr-Ni stainless steel magnet. The slot is of a single layer type, The rib is made of a non-magnetic portion having the same composition as the Cr-Ni stainless steel magnet, The permanent magnet is a rare earth anisotropic bonded magnet injection molded in the slot to which a polar anisotropic aligning magnetic field is applied; The magnet end region from the outer circumferential end of the permanent magnet to the outer circumferential end of the rotor core is characterized by being made of a non-magnetic portion.

[0031] The rotor of the first embodiment of the present invention has six magnetic poles, each of which has a single row of single-layer bonded magnets and one rib sandwiched between the bonded magnets. The outer periphery of the rotor is made up of a magnet end region that extends from the outer periphery end of one bond magnet to the outer periphery end of the rotor core. A detailed explanation will be given below with reference to FIG. 1, FIG. 2 and FIG.

[0032] 1 is a front view of the motor M1. As shown in FIG 1, the motor M1 includes an annular stator 50 and a rotor 1 disposed inside the stator 50. The rotor 1 is an interior permanent magnet (IPM) type rotor, and includes a rotor core 11 and a plurality of magnetic pole portions. In this embodiment, the rotor 1 includes six magnetic pole portions. 2 is a cross-sectional view of rotor 1 in this embodiment. Rotor 1 comprises rotor core 11, single-layer bonded magnets 121-126, ribs 131-136 made of non-magnetic portions sandwiched between divided bonded magnets, and magnet end regions 141a·141b-146a·146b of non-magnetic portions at both ends of the bonded magnets.

[0033] The rotor core 11 is made of a stainless steel magnet. A thin plate of 18Cr-8Ni stainless steel, a semi-hard magnetic material that is in a non-magnetic austenite phase at room temperature and becomes a magnetic martensite phase after cold working, is punched out, forming a single layer of slots (single row of first magnet holes) in the radial direction, and then the ribs and the areas corresponding to the magnet end regions are modified to form non-magnetic 18Cr-8Ni stainless steel (non-magnetic portion). This formed rotor blank is then insulated and laminated to form the rotor core 11. Thereafter, in the polar anisotropic oriented magnetic field of the bonded magnet, the rotor blank is magnetized from the semi-hard magnetic material to oriented saturation, becoming a stainless steel magnet, which is a permanent magnet. Its magnetic properties are as follows: saturation magnetization of 15,000 G, coercivity of 120 Oe, residual magnetization Br of 7,000 G, and maximum energy product of 2.0 MGOe at room temperature.

[0034] FIG. 5 is a partial view of a rotor core showing (a) a punched material with slots formed therein, (b) a nonmagnetic portion in the magnet end region of embodiment 1, and (c) a nonmagnetic portion in the outer peripheral region between the magnetic poles of embodiment 2. (a) Slotted stamping shows slots 1210, 1220 separated by ribs 1310, 1320 and magnet bore (magnet) end regions 1410, 1420 between the slots and the outer periphery of the rotor core (periphery edge). The punched material was modified by local heating the areas corresponding to the ribs and magnet end regions (magnet hole end regions) to 900°C with a laser. This resulted in a non-magnetic area with a magnetic permeability of 1.2 or less. Furthermore, since the heating temperature was just enough to return the martensite structure to the austenite phase, no deformation or distortion occurred in the thin plates, allowing them to be easily stacked.

[0035] When viewed in the axial direction of the rotor shaft, rotor core 11 is formed in an arc shape that opens radially outward, and is made up of magnet holes in which bonded magnets are embedded. Hereinafter, the direction of the rotation axis of rotor core 11 will be referred to as the axial direction, the radial direction of rotor core 11, and the circumferential direction of rotor core 11 as the circumferential direction.

[0036] The first magnetic path is provided radially outward from the magnet hole (bonded magnet 121). That is, the first magnetic path is provided between the magnet hole and the outer peripheral edge (not shown) of rotor core 11. The second magnetic path is provided radially inward from the magnet hole (bonded magnet 121).

[0037] The first and second magnetic paths are formed on rotor core 11 made of stainless steel magnet. This stainless steel magnet has magnetomotive force, so it reinforces the magnetic flux from the bonded magnet, and a stronger torque can be obtained compared to bonded magnet 12 alone.

[0038] Rib 13 extends along the magnetic pole center line extending in the radial direction, and blocks the first magnetic path and the second magnetic path, while rib 13 also blocks leakage of magnetic flux from bond magnet 12 in the magnet hole. The rib 13 divides the magnet hole into two magnet holes along the circumferential direction.

[0039] Since the ribs 13 are made of the original 18Cr-8Ni non-magnetic stainless steel, the magnetic flux is blocked and the magnetic flux from the bonded magnet combines with the magnetomotive force of the stainless steel magnet to contribute to the formation of a large amount of magnetic flux. In addition, since it has superior toughness compared to electromagnetic steel sheets (silicon steel sheets), it has improved centrifugal resistance and enables the motor to rotate at a higher speed.

[0040] Magnet end region 14 (141-146) is a connection portion (connection area) that extends from the outer peripheral end of the magnet hole in which the bonded magnet is embedded to the outer peripheral end of rotor core 11, and is formed as part of the outer periphery of rotor core 11. Magnet end region 14 is made of 18Cr-8Ni nonmagnetic stainless steel, and its nonmagnetic nature uniformly induces a strong polar anisotropic aligning magnetic field into the magnet hole where the bonded magnet is injection molded. That is, in the flow of the polar anisotropic aligning magnetic field applied from the outside of rotor core 11, the leakage magnetic flux that flows directly from the inner magnetic pole side to the outer magnetic pole side via a specific part of the outer peripheral region of the end can be drastically reduced, thereby strengthening the polar anisotropic aligning magnetic field that contributes to the orientation.

[0041] In addition, since the magnet end region 14 is made of the same 18Cr-8Ni non-magnetic stainless steel as the above-described rib 13, leakage of magnetic flux from the end of the bonded magnet 12 is avoided, and an effective amount of magnetic flux is ensured. Furthermore, since it is 18Cr-8Ni non-magnetic stainless steel, it has excellent mechanical properties and has only been modified by local heating, so the accuracy during the production of the rotor 1 is maintained as it is, which is optimal for the high-speed rotation of the rotor 1.

[0042] The bonded magnet 12 is composed of Nd-Fe-B rare earth magnet powder and a binder resin. In this embodiment, Nd-Fe-B magnet powder is used, but Sm-Co magnet powder or Sm-Fe-N magnet powder may also be used. Also, these rare earth anisotropic magnet powders may consist of not only one kind but also a plurality of kinds.

[0043] For the binder resin, a polyamideimide-based thermoplastic resin was used. Note that known materials such as thermoplastic resins such as polyethylene and thermosetting resins such as melamine resin can be appropriately used.

[0044] The bonded magnet 12 consists of two divided magnets, which are respectively filled in the divided magnet holes 12.

[0045] In this embodiment, a pole anisotropic magnetic field was applied to the slot 12 from the start of filling to the end of filling of the molten mixture in injection molding. At this time, the pole anisotropic magnetic field was 0.7 T, the temperature of the molten mixture was 300 °C, the injection pressure was 100 MPa, and the injection speed was 80 mm / sec.

[0046] As a result, the magnet particles in the permanent magnet not only orient during injection molding in a magnetic field but are also magnetized simultaneously, and the permanent magnet is already in a state of exhibiting a high magnetic flux density. Therefore, in this embodiment, there was no need to perform post-magnetization.

[0047] [Second Embodiment] The second embodiment of the rotor of the IPM motor of the present invention is A rotor for an IPM motor, comprising: a rotor core made of stainless steel magnets and having an even number of slots each having an air gap arranged axially symmetrically around a central axis of rotation; ribs provided between the slots; and an even number of permanent magnets formed in the slots, The rotor core is made of Cr-Ni stainless steel magnet. The slot is of a single layer type, The rib is made of a non-magnetic portion having the same composition as the Cr-Ni stainless steel magnet, The permanent magnet is a rare earth anisotropic bonded magnet injection molded in the slot to which a polar anisotropic aligning magnetic field is applied; The magnet end outer circumferential region, which is composed of a magnet end region extending from the outer circumferential end of the permanent magnet to the outer circumferential end of the rotor core, a magnet end region extending from the outer circumferential end of another permanent magnet adjacent to the permanent magnet to the outer circumferential end of the rotor core, and a connecting portion connecting the magnet end regions, is made of a non-magnetic portion.

[0048] The rotor according to the second embodiment of the present invention is In the first embodiment, in addition to magnet end region 14 of each bonded magnet 12, magnet end outer peripheral region 25 including the connection portion between the magnet end region of another adjacent magnetic pole portion is formed in the non-magnetic portion. The following description will be given with reference to FIG. 3, FIG. 4 and FIG.

[0049] 3 is a front view of the motor M2. As shown in FIG. 3, the motor M2 includes an annular stator 50 and a rotor 2 disposed inside the stator 50. The rotor 2 is an interior permanent magnet (IPM) type rotor, and includes a rotor core 21 and a plurality of magnetic pole portions. In this embodiment, the rotor 2 includes six magnetic pole portions. 4 is a cross-sectional view of rotor 2 in this embodiment. Rotor 2 includes rotor core 21, which includes single-layer bonded magnets 221-226, ribs 231-236 made of nonmagnetic portions sandwiched between divided bonded magnets, and magnet end outer circumferential regions 251-256 of the nonmagnetic portions including connecting portions at both ends of the bonded magnets.

[0050] The rotor core 11 is made of a stainless magnet. The manufacturing method and magnetization are the same as those in the first embodiment. Also, the bonded magnet 22 and its manufacturing method are the same as those in the first embodiment.

[0051] Regarding the magnet performance, in addition to the first embodiment, by forming a connecting portion of a non-magnetic portion at both ends of the bonded magnet, the leakage of magnetic flux between magnetic poles, between 141b and 142a in Embodiment 1, is blocked by the non-magnetic portion 251 in Embodiment 2. Thereby, a more effective magnetic flux amount is further ensured.

[0052] [Third Embodiment] The third embodiment of the rotor of the IPM motor of the present invention is a rotor of an IPM motor including a rotor core made of a stainless steel magnet and having an even number of slots formed by axially symmetrically arranged voids around the rotation center axis, ribs provided between the slots, and an even number of permanent magnets formed in the slots, wherein the rotor core is made of a Cr-Ni series stainless magnet, the slots are of a multilayer type, the ribs are made of a non-magnetic portion having the same composition as the Cr-Ni series stainless magnet, the permanent magnets are made of rare earth anisotropic bonded magnets injection-molded in the slots with a pole anisotropic magnetic field applied, and in one magnetic pole, a magnetic pole inner and outer peripheral region (between the same magnetic poles) composed of a magnetic pole end region extending from the outer peripheral side end of the permanent magnet to the outer peripheral side end of the rotor core, a magnetic pole end region extending from the other end of another permanent magnet adjacent to the permanent magnet to the outer peripheral end of the rotor core, and a connecting portion connecting the magnetic pole end regions is made of a non-magnetic portion.

[0053] [Fourth Embodiment] The fourth embodiment of the rotor of the IPM motor of the present invention is A rotor for an IPM motor, comprising: a rotor core made of stainless steel magnets and having an even number of slots each having an air gap arranged axially symmetrically around a central axis of rotation; ribs provided between the slots; and an even number of permanent magnets formed in the slots, The rotor core is made of Cr-Ni stainless steel magnet. The slot is of a multi-layer type, The rib is made of a non-magnetic portion having the same composition as the Cr-Ni stainless steel magnet, The permanent magnet is a rare earth anisotropic bonded magnet injection molded in the slot to which a polar anisotropic aligning magnetic field is applied; The magnetic pole inner / outer circumference region within one magnetic pole, the magnetic pole inner / outer circumference region within another adjacent magnetic pole, and the magnet end outer circumference region (between adjacent magnetic poles), which consists of a connecting portion connecting the two, are characterized by being made of non-magnetic parts.

[0054] The third and fourth embodiments are embodiments in which the single-layer slot in the first and second embodiments is changed to a multi-layer slot. Examples of the multi-layer type include a two-layer bonded magnet with two rows of magnets in an eight-pole magnetic pole section, and a four-layer bonded magnet with four rows of magnets and multiple ribs sandwiched between the bonded magnets. In addition, on the outer periphery of the rotor, within one magnetic pole, there is a magnetic pole inner / outer periphery side region (between the same magnetic poles) consisting of a magnet end region that extends from the outer periphery end of the permanent magnet to the outer periphery end of the rotor core, a magnet end region that extends from the other end of another permanent magnet adjacent to the permanent magnet to the outer periphery end of the rotor core, and a connecting portion that connects the magnet end regions. The magnetic pole inner and outer periphery side region in one magnetic pole, the magnetic pole inner and outer periphery side region in another adjacent magnetic pole, and a connecting portion connecting both (the magnetic pole inner and outer periphery side regions of the adjacent magnetic poles) are formed. Four types of rotors combining two-layer and four-layer slots, inner and outer periphery regions of magnetic poles (between the same magnetic poles), and outer periphery regions between magnetic poles (between adjacent magnetic poles) will be described in detail below with reference to FIGS. 6 to 14.

[0055] [2-layer type-A] A two-layer rotor having inner and outer circumferential regions (between the same magnetic poles) will be described with reference to FIGS. 6 and 7. FIG. Fig. 6 is a front view of the motor M2. As shown in Fig. 6, the motor M2 includes an annular stator 60 and a rotor 3 disposed inside the stator 60. The rotor 3 is an interior permanent magnet type (IPM) and includes a rotor core 31 and an eight-pole magnetic pole portion 36. 7 is a cross-sectional view of magnetic pole portion 36 of rotor 3 in this embodiment. Magnetic pole portion 36 is two-layered in rotor core 31, and includes first bonded magnet 321M in the first layer, second bonded magnet 322M in the second layer, first rib 33, and second ribs 34A, 34B, and 34C. In addition, along the outer peripheral end (outer peripheral edge) of rotor core 31, there is provided a non-magnetic inner / outer peripheral region (between the same magnetic poles) 35 consisting of the magnet end region of first bond magnet 321M, the magnet end region of second bond magnet 322M, and a connecting portion connecting the outer peripheral ends of both.

[0056] The rotor core 31 is made of a stainless steel magnet. The manufacturing method, magnetization and magnetic performance are the same as those in the first embodiment. Furthermore, the method of forming the nonmagnetic ribs 33, 34A, 34B, and 34C by modification and the magnetic pole inner and outer periphery side regions (between the same magnetic poles) 35 is the same as in the first embodiment.

[0057] First bond magnet 321M is formed in an arc shape that opens outward in the radial direction of rotor core 31 when viewed in the axial direction of the rotation shaft of rotor core 31. Hereinafter, the direction of the rotation axis of rotor core 31 will be referred to as the axial direction, the radial direction of rotor core 31, and the circumferential direction of rotor core 31 as the circumferential direction. Second bond magnet 322M is provided radially inward of first bond magnet 321M when viewed in the axial direction. Second bond magnet 321M is formed in an arc shape that opens radially outward.

[0058] First magnetic path 171 is provided radially outward from first bond magnet 321M. That is, first magnetic path 171 is provided between first bond magnet 321M and outer peripheral edge 311 of rotor core 31. Second magnetic path 172 is provided radially inward from first bond magnet 321M and radially outward from second bond magnet 322M. Third magnetic path 173 is provided radially inward from second bond magnet 322M.

[0059] First magnetic path 171 to third magnetic path 173 are formed on rotor core 31 made of a stainless steel magnet. This stainless steel magnet has a magnetomotive force, so it reinforces the magnetic flux from the bonded magnet, and a stronger torque can be obtained compared to using only the bonded magnet.

[0060] First rib 33 extends along the magnetic pole center line and blocks first magnetic path 171 and second magnetic path 172, and also blocks leakage of magnetic flux from first bonded magnet 321M. The first rib 13 divides the first magnet hole 321 into two magnet holes along the circumferential direction.

[0061] Second ribs 34 are made up of three ribs 34A, 34B, and 34C, which block second magnetic path 172 and third magnetic path 173, and divide second magnet hole 322 into three magnet holes. The second rib 34A extends along the magnetic pole center line. The second rib 34B and the second rib 34C are provided on either side of the second rib 34A.

[0062] Second rib 34 blocks second magnetic path 172 and third magnetic path 173, and also blocks leakage of magnetic flux from second bond magnet 322M in second magnet hole 322.

[0063] Since the first rib 33 and the second rib 34 are made of the original 18Cr-8Ni non-magnetic stainless steel, the magnetic flux is blocked and the magnetic flux from the bonded magnet combines with the magnetomotive force of the stainless steel magnet to contribute to the formation of a large amount of magnetic flux. In addition, since it has superior toughness compared to electromagnetic steel sheets (silicon steel sheets), it has improved centrifugal resistance and enables the rotation speed of the motor to be increased.

[0064] There are two magnetic pole inner and outer periphery side regions (between the same magnetic poles) 35, which are composed of a magnet end region of first bond magnet 321M, a magnet end region of second bond magnet 322M, and a connecting portion that connects the outer periphery ends of both magnets. It is formed along the outer circumferential side (outer circumferential edge) 311 of the rotor core 31 . Furthermore, since the inner and outer circumferential regions (between the same magnetic poles) 35 are made of the same 18Cr-8Ni nonmagnetic stainless steel as the above-mentioned ribs, leakage of magnetic flux from the end of first bonded magnet 321M on the outer circumferential edge 311 side and the end of second bonded magnet 322M on the outer circumferential edge 311 side is prevented, and an effective amount of magnetic flux is ensured.

[0065] First bonded magnet 321M and second bonded magnet 322M are made of Nd-Fe-B rare earth magnet powder and binder resin. First bond magnet 321M is made up of two divided magnets, which are filled into first magnet holes 121, respectively. Second bond magnet 322M is made up of three divided magnets, which are filled into second magnet holes 122, respectively.

[0066] In this embodiment, a polar anisotropic aligning magnetic field was applied to the slot 12 from the start of filling the molten mixture to the end of filling during injection molding. At this time, the polar anisotropic aligning magnetic field was 0.7 T, the temperature of the molten mixture was 300° C., the injection pressure was 100 MPa, and the injection speed was 80 mm / sec.

[0067] As a result, the magnetic particles in the permanent magnet M1 are not only oriented during injection molding in a magnetic field, but are also simultaneously magnetized, so that the permanent magnet M1 already has a high magnetic flux density. For this reason, in this embodiment, there was no need to perform post-magnetization.

[0068] 6, the magnetization vectors of first bonded magnet 321M and second bonded magnet 322M face from the inside to the outside in the radial direction. In another magnetic pole portion 36 (not shown) adjacent to this magnetic pole portion 36, the magnetization vectors of first bonded magnet 321M and second bonded magnet 322M face from the outside to the inside in the radial direction.

[0069] [2-layer type-B] A two-layer rotor consisting of an inter-pole outer peripheral region (between adjacent poles) will be described with reference to Figures 8 and 9. The two-layer type-B is obtained by adding a connecting portion between the magnetic poles to the two-layer type-A. Fig. 8 is a front view of the motor M2. As shown in Fig. 8, the motor M2 includes an annular stator 60 and a rotor 4 disposed inside the stator 60. The rotor 4 is an interior permanent magnet type (IPM) and includes a rotor core 41 and an eight-pole magnetic pole portion 47. 9 is an enlarged cross-sectional view of magnetic pole portion 47 of rotor 4 in this embodiment. Magnetic pole portion 47 is two-layered in rotor core 41, and includes first bonded magnet 421M in the first layer, second bonded magnet 422M in the second layer, first rib 43, and second ribs 44A, 44B, and 44C. In addition, along the outer periphery (outer edge) of rotor core 41, there is provided a non-magnetic inter-pole outer periphery side region (between adjacent magnetic poles) 46 consisting of the magnet end region of first bond magnet 421M, the magnet end region of second bond magnet 422M, and a connecting portion connecting the outer periphery ends of both.

[0070] This two-layer type-B can prevent leakage of magnetic flux from between the magnetic poles, thereby ensuring an even greater amount of effective magnetic flux.

[0071] The rotor core 41 is made of a stainless steel magnet. The manufacturing method, magnetization, and magnetic performance are the same as those in the first embodiment. Furthermore, the method of forming the non-magnetic ribs 43, 44A, 44B, and 44C by modification and the inter-pole outer periphery side region (between adjacent magnetic poles) 35 is the same as in the first embodiment. In addition, the formation of the magnetic path is almost the same as the two-layer type-A.

[0072] [4-layer type-A] A four-layer rotor having inner and outer circumferential regions (between the same magnetic poles) will be described with reference to Figs. Fig. 10 is a front view of the motor M3. As shown in Fig. 10, the motor M3 includes an annular stator 70 and a rotor 5 disposed inside the stator 70. The rotor 5 is an interior permanent magnet type (IPM) and includes a rotor core 51 and an eight-pole magnetic pole portion. 10 is a cross-sectional view of the magnetic pole portion of rotor 5 in this embodiment. The magnetic pole portion is made of four layers in rotor core 51, and includes first bond magnet 521 in the first layer to fourth bond magnet 524 in the fourth layer, and first rib 531 to fourth rib 534. The magnet row of bonded magnets in the first layer to the magnet row of bonded magnets in the fourth layer are formed in a U-shaped arc, and share the same center point. There are two first bond magnets 521, four second bond magnets 522, five third bond magnets 523, and seven fourth bond magnets 524. Hereinafter, bond magnets 521 to 524 will be abbreviated as bond magnets 52. There is one first rib 531, three second ribs 532, four third ribs 533, and six fourth ribs. Hereinafter, the ribs 531 to 534 are abbreviated to ribs 53.

[0073] Moreover, magnetic pole inner / outer periphery side region (between the same magnetic poles) 57 is formed along outer periphery side (outer periphery edge) 511 of rotor core 51, and is composed of four magnet end regions and three connecting parts. The connecting part connects the magnet end region of first bond magnet 521 and the magnet end region of second bond magnet 522 to their outer periphery ends, the connecting part connects the magnet end region of second bond magnet 522 and the magnet end region of third bond magnet 523 to their outer periphery ends, and the connecting part connects the magnet end region of third bond magnet 523 and the magnet end region of fourth bond magnet 524 to their outer periphery ends.

[0074] Compared to the two-layer bonded magnets (magnet arrays) of [2-layer type-A] and [2-layer type-B], a more multi-layered bonded magnet (magnet array) can obtain greater output torque, making it possible to use a large IPM.

[0075] Ribs 53 are made of non-magnetic stainless steel by modification, and are disposed between the divided bonded magnets of bonded magnets 521 to 524. The method of forming ribs 53 is the same as in the first embodiment. The ribs 53 made of non-magnetic stainless steel block leakage of magnetic flux from the bonded magnet formed in the magnet hole, so that the magnetic flux of the bonded magnet combines with the electromotive force of the stainless steel magnet to indirectly contribute to the formation of a large amount of magnetic flux. In addition, since it has superior toughness compared to electromagnetic steel sheets, it has improved centrifugal resistance and can increase the rotation speed of the motor.

[0076] The inner and outer periphery regions (between the same magnetic poles) 57 are made of 18Cr-8Ni non-magnetic stainless steel, and due to this non-magnetic property, a strong polar anisotropic aligning magnetic field is uniformly induced into the magnet holes where the bonded magnets are injection molded. That is, in the flow of the polar anisotropic aligning magnetic field applied from the outside of rotor core 51, the leakage magnetic flux that flows directly from the inner magnetic pole side to the outer magnetic pole side via a specific part of the outer periphery region at the end is drastically reduced, thereby strengthening the polar anisotropic aligning magnetic field that contributes to the orientation.

[0077] Furthermore, since the inner and outer periphery region 57 of the magnetic pole (between the same magnetic poles) is made of the same 18Cr-8Ni nonmagnetic stainless steel as the ribs described above, leakage of magnetic flux from the end on the outer periphery of the bonded magnet is prevented and an effective amount of magnetic flux is ensured. Furthermore, since it is 18Cr-8Ni non-magnetic stainless steel, it has excellent mechanical properties, and since it is merely modified by localized heating, the precision at the time of rotor 5's manufacture is maintained, making rotor 5 ideal for high-speed rotation.

[0078] The bond magnet 52 is made of Nd-Fe-B rare earth magnet powder and binder resin. The magnet powder and binder resin of this embodiment are the same as those of the first embodiment. Bonded magnet 32 ​​is made up of two divided magnets, each of which is filled into a divided magnet hole. In this embodiment, a polar anisotropic aligning magnetic field was applied to the slit 12 from the start of filling the molten mixture to the end of filling during injection molding. At this time, the polar anisotropic aligning magnetic field was 0.7 T, the temperature of the molten mixture was 300° C., the injection pressure was 120 MPa, and the injection speed was 80 mm / sec.

[0079] [4 layer type-B] A four-layer rotor consisting of an inter-pole outer peripheral region (between adjacent magnetic poles) will be described with reference to Figures 12 to 14. The four-layer type-B is obtained by adding a connection between the magnetic poles to the four-layer type-A. Fig. 12 is a front view of the motor M3. As shown in Fig. 12, the motor M3 includes an annular stator 60 and a rotor 6 disposed inside the stator 60. The rotor 6 is an interior permanent magnet type (IPM) and includes a rotor core 61 and an eight-pole magnetic pole portion. 13 is an enlarged cross-sectional view of one magnetic pole portion of rotor 6 in this embodiment. The magnetic pole portion is made up of four layers in rotor core 61, bonded magnet 62 made up of first bonded magnet 621 in the first layer, second bonded magnet 622 in the second layer, third bonded magnet 623 in the third layer, and fourth bonded magnet 624 in the fourth layer, and rib 63 made up of first rib 631, second rib 632, third rib 633, and fourth rib 634. In addition, the inter-pole outer peripheral region (between adjacent magnetic poles) 68 is formed along the outer peripheral side (outer peripheral edge) of the rotor core 61, and is made up of four magnet end regions and three connecting portions that connect the magnetic pole inner / outer peripheral region (between the same magnetic poles) of an adjacent magnetic pole to the magnetic pole inner / outer peripheral region (between the same magnetic poles) of the adjacent magnetic pole.

[0080] In addition to the four-layer type A, the four-layer type B can prevent leakage of magnetic flux from between the magnetic poles, thereby ensuring an even greater amount of effective magnetic flux.

[0081] Here, the rotor core blank obtained by punching out a four-layer rotor core (representative of type B) will be described with reference to FIG. Rotor core blank 600 is made of a semi-hard magnetic material, and rotor core 610 is formed by punching out four magnet hole rows in an arc shape, from first magnet hole 6210 to fourth magnet hole 6240. Each magnet hole is divided, and first ribs 6310 to fourth ribs 6340 are formed between the magnet holes. In this example, there is one first rib 6310 and two first magnet holes 6210. There are three second ribs 6320 and four second magnet holes 6220. There are four third ribs 6330 and five third magnet holes 6230. There are six fourth ribs 6340 and seven fourth magnet holes 6240.

[0082] The region (magnet hole end region) corresponding to the magnet end region in rotor core 610 is between outer circumferential edge portion (outer circumferential side end portion) 611 and the magnet holes of rotor core 610. Between first magnet hole 6210 and outer circumferential edge 611 is magnet hole end region 641, hereafter referred to as magnet hole end regions 642 to 644. The portions connecting each magnet hole end region are referred to as connecting portions.

[0083] The four magnet hole end regions and three connecting parts mentioned above are all located on the outer periphery of the same magnetic pole, and are therefore collectively referred to as the inner and outer periphery regions of the magnetic pole (within the same magnetic pole). This corresponds to the two-layer and four-layer A types.

[0084] Furthermore, a connection is provided between the inner and outer periphery regions of one magnetic pole and the inner and outer periphery regions of another adjacent magnetic pole, and these are collectively called the inter-pole outer periphery region (between adjacent magnetic poles). This corresponds to the two-layer and four-layer B types.

[0085] [Fifth embodiment] The fifth embodiment of the present invention relates to a manufacturing method and a manufactured rotor using non-magnetic Fe-Mn steel plate (SMn45), which is made of the same single-layered bonded magnet as the second embodiment, and has one rib sandwiched between the bonded magnets, a magnet end region extending from the outer periphery of one bonded magnet to the outer periphery of the rotor core, a magnet end region extending from the outer periphery of another bonded magnet adjacent to one bonded magnet to the outer periphery of the rotor core, and a connecting portion connecting the magnet end regions. For the figure, refer to FIG. 4.

[0086] The process is as follows. (1) Base material molding process A 2.0 mm thick SMn45 non-magnetic steel plate is cold-rolled to a 0.5 mm thin plate, which is then subjected to a low-temperature cooling treatment at -70°C for 30 minutes to form a base material of semi-hard magnetic material consisting of 85% martensite structure. (2) Punching process A base material made of a semi-hard magnetic material is punched out to form a rotor core blank having 12 arc-shaped magnet holes (slots). (3)Heating process The six ribs sandwiched between the two magnet holes and the six outer peripheral ends between the outer peripheral edge of the rotor core and the outermost magnet hole that forms an arc are locally heated to 920°C with a laser to demagnetize them, forming a rotor preform consisting of nonmagnetic portions.

[0087] (4) Rotor blank forming process An organic resin-based insulating resin coating is applied to the rotor blank to form an insulating film, and then the insulating coated rotor blank is stacked. In the stacking process, the rotor plates are stacked so that the anisotropy of the stainless steel magnets is radial anisotropy. If the rotor plates have uniaxial anisotropy, they are stacked with the orientation rotated according to the number of magnetic poles so that the stack as a whole has radial anisotropy. (5) Injection molding process Using an injection molding machine in a magnetic field, rare earth anisotropic bonded magnets are filled into the magnet holes (slots) of the laminated rotor blanks. Bonded magnets consist of Nd-Fe-B rare earth magnet powder and binder resin. The magnet powder and binder resin of this embodiment are the same as those of the first embodiment. The bonded magnet consists of two divided magnets, each of which is filled into a divided magnet hole. In this embodiment, a polar anisotropic aligning magnetic field was applied to the slot from the start of filling the molten mixture to the end of filling during injection molding. At this time, the polar anisotropic aligning magnetic field was 0.7 T, the temperature of the molten mixture was 300°C, the injection pressure was 80 MPa, and the injection speed was 80 mm / sec. By polar anisotropic alignment, the semi-hard magnetic material was saturation magnetized to a manganese magnet, and at the same time, the rare earth anisotropic bonded magnet was saturation magnetized.

[0088] (6) Inspection process The magnetic field emitted from each magnetic pole of the rotor is measured to check whether the rare earth anisotropic bonded magnets and manganese magnets are saturated. The rotor is rotated and the magnetic field distribution in the circumferential direction is measured to confirm that the magnetic field distribution is a sine wave. (7) Rotor Through the above steps, a rotor is obtained. [Industrial Applicability]

[0089] The motors can be widely used as vehicle drive motors used in electric vehicles, hybrid vehicles, railroad cars, etc., home appliance motors used in air conditioners, refrigerators, washing machines, etc., and drive motors for various robot devices. [Explanation of symbols]

[0090] M1: Motor (IPM (internal magnet synchronous machine)) 1: Rotor 11: rotor core, 12: Bonded magnets (121-126) 13: Rib (131-136) 14: Magnet end area (141a・141b~146a・146b) 15: Center hole (shaft hole) 50:Stator

[0091] M1: Motor (IPM (internal magnet synchronous machine)) 2: Rotor 21:Rotor core 22: Bonded magnets (221-226) 23: Rib (231-236) 25: Outer area between magnetic poles (251~256) 50:Stator

[0092] 30: Rotor core material (punched product) 110:Rotor core 110e: Rotor core outer periphery (outer periphery) 1210, 1220: Magnet hole 1310, 1320: Ribs 1310: magnet end region (between 1210 and 110e) 1320: magnet end region (between 1220 and 110e) 30A: Non-magnetic portion of the magnet end region (part of embodiment 1) 121, 122: Bonded magnets 131, 132: Ribs 141a, 141b: non-magnetic parts of magnet end regions 142a, 142b: non-magnetic parts of magnet end regions 30B: Non-magnetic portion of the outer peripheral region between the magnetic poles (part of embodiment 2) 221, 222: Bonded magnets 231, 232: Ribs 251, 252: Non-magnetic parts of the outer periphery area between the magnetic poles

[0093] M2: Motor (IPM (internal magnet synchronous machine)) 3: Rotor 31: Rotor core 311: Outer periphery end (outer periphery) 321M: 1st bonded magnet 322M: Second bonded magnet 33: First Rib 34A, 34B, 34C: Second rib 35:Magnetic pole inner and outer peripheral areas 36: Magnetic pole (magnetic pole part) 60:Stator

[0094] M2: Motor (IPM (internal magnet synchronous machine)) 4: Rotor 41: Rotor core 411: Outer periphery end (outer periphery) 421M: 1st bonded magnet 422M: Second bonded magnet 43: First Rib 44A, 44B, 44C: Second rib 46: Outer area between magnetic poles 47: Magnetic pole (magnetic pole part) 60:Stator

[0095] M3: Motor (IPM (internal magnet synchronous machine)) 5: Rotor 51: Rotor core 511: Outer periphery end (outer periphery) 521: First bonded magnet 522: Second bonded magnet 523: 3rd bond magnet 524: 4th bonded magnet 531: First Rib 532: 2nd Rib 533: 3rd Rib 534: 4th Rib 57:Magnetic pole inner and outer peripheral areas 70:Stator

[0096] M3: Motor (IPM (internal magnet synchronous machine)) 6: Rotor 61: Rotor core 611: Outer periphery end (outer periphery) 621: First bonded magnet 622: Second bonded magnet 623: 3rd bonded magnet 624: 4th bonded magnet 631: First Rib 632: 2nd Rib 633: 3rd Rib 634: 4th Rib 68: Outer area between magnetic poles 70:Stator

[0097] 600: Rotor core material 610: Rotor core 611: Outer periphery end (outer periphery) 6210: First magnet hole 6220: Second magnet hole 6230: 3rd magnet hole 6240: 4th magnet hole 6310: First Rib 6320: 2nd rib 6330: 3rd rib 6340: 4th Rib

Claims

1. A rotor for an IPM motor, comprising: a rotor core having an even number of slots each having an air gap symmetrically arranged around a central axis of rotation; a rib provided between the slots; and an even number of permanent magnets formed in the slots, The rotor core is made of a Cr-Ni stainless steel magnet. The slot is of a single layer type, The rib is made of a non-magnetic portion having the same composition as the Cr-Ni stainless steel magnet, The permanent magnet is a rare earth anisotropic bonded magnet injection molded in the slot to which an aligning magnetic field is applied polar anisotropically; a magnet end region extending from the outer peripheral end of the permanent magnet to the outer peripheral end of the rotor core is made of a non-magnetic portion obtained by non-magnetically modifying a Cr-Ni stainless steel magnet; The rotor of an IPM motor is characterized in that the rare earth anisotropic bonded magnet is polar anisotropically magnetized.

2. A rotor for an IPM motor, comprising: a rotor core having an even number of slots each having an air gap symmetrically arranged around a central axis of rotation; a rib provided between the slots; and an even number of permanent magnets formed in the slots, The rotor core is made of a Cr-Ni stainless steel magnet. The slot is of a single layer type, The rib is made of a non-magnetic portion having the same composition as the Cr-Ni stainless steel magnet, The permanent magnet is a rare earth anisotropic bonded magnet injection molded in the slot to which an aligning magnetic field is applied polar anisotropically; an inter-pole outer circumferential region consisting of a magnet end region extending from the outer circumferential end of said permanent magnet to the outer circumferential end of said rotor core, a magnet end region extending from the outer circumferential end of another permanent magnet adjacent to said permanent magnet to the outer circumferential end of said rotor core, and a connection portion connecting said magnet end regions, is made of a non-magnetic portion having the same composition as a Cr-Ni stainless steel magnet, The rotor of an IPM motor is characterized in that the rare earth anisotropic bonded magnet is polar anisotropically magnetized.

3. A rotor for an IPM motor, comprising: a rotor core having an even number of slots each having an air gap symmetrically arranged around a central axis of rotation; a rib provided between the slots; and an even number of permanent magnets formed in the slots, The rotor core is made of a Cr-Ni stainless steel magnet. The slot is of a multi-layer type, The rib is made of a non-magnetic portion having the same composition as the Cr-Ni stainless steel magnet, The permanent magnet is a rare earth anisotropic bonded magnet injection molded in the slot to which an aligning magnetic field is applied polar anisotropically; a magnet end region extending from the outer peripheral end of the permanent magnet to the outer peripheral end of the rotor core is made of a non-magnetic portion having the same composition as the Cr-Ni stainless steel magnet; The rotor of an IPM motor is characterized in that the rare earth anisotropic bonded magnet is polar anisotropically magnetized.

4. A rotor for an IPM motor, comprising: a rotor core having an even number of slots each having an air gap symmetrically arranged around a central axis of rotation; a rib provided between the slots; and an even number of permanent magnets formed in the slots, The rotor core is made of a Cr-Ni stainless steel magnet. The slot is of a multi-layer type, The rib is made of a non-magnetic portion having the same composition as the Cr-Ni stainless steel magnet, The permanent magnet is a rare earth anisotropic bonded magnet injection molded in the slot to which an aligning magnetic field is applied polar anisotropically; an inter-pole outer circumferential region consisting of a magnet end region extending from the outer circumferential end of said permanent magnet to the outer circumferential end of said rotor core, a magnet end region extending from the outer circumferential end of another permanent magnet adjacent to said permanent magnet to the outer circumferential end of said rotor core, and a connection portion connecting said magnet end regions, is made of a non-magnetic portion having the same composition as a Cr-Ni stainless steel magnet, The rotor of an IPM motor is characterized in that the rare earth anisotropic bonded magnet is polar anisotropically magnetized.

5. In any one of claims 1 to 4, A rotor for an IPM motor, characterized in that the rotor core is made of an Fe-Mn alloy magnet, and the non-magnetic portion has the same composition as the Fe-Mn alloy magnet.

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