Permanent magnet rotor
The laminated core with protruding permanent magnets and fluid passages in the permanent magnet rotor addresses structural and heat dissipation issues, enhancing magnetic flux and fluid circulation, thereby improving motor performance and efficiency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-03-06
- Publication Date
- 2026-04-14
AI Technical Summary
Existing permanent magnet rotors face challenges such as reduced magnetic flux due to manufacturing tolerances, restricted structural configurations, and inadequate heat dissipation, especially in high-frequency brushless BLDC motors used for fluid pumps, where the magnets fall back behind the laminated core and lack optimal fluid flow mechanisms.
The design includes a laminated core formed from two sub-cores with magnet housing pockets, allowing permanent magnets to protrude axially, enhancing magnetic flux and fluid circulation, and incorporating fluid passages for improved heat dissipation, with adaptable configurations for different motor requirements.
This design increases magnetic flux density, enhances motor output, and efficiently dissipates heat while optimizing fluid flow, addressing structural limitations and improving motor performance without increasing dimensions.
Smart Images
Figure 2026511688000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a permanent magnet rotor according to claim 1.
Background Art
[0002] Permanent magnet rotors are used as important components, for example, in electric motors that can drive fluid pumps. Sometimes, in this type of application area, brushless BLDC motors are increasingly being used with very high frequencies. The use of permanent magnet rotors is known, in which pockets are provided inside a sheet pack stack (consisting of individually punched sheets) for accommodating and fixing the permanent magnets. Usually, the permanent magnets are arranged in these pockets such that their axial length is adapted to or shorter than the axial length of the sheet pack of the permanent magnet rotor (hereinafter referred to as the laminated core) in the axial direction, and they are arranged to fall back behind the laminated core.
[0003] Due to manufacturing technology reasons, the laminated core always has a much larger tolerance range than the permanent magnets. The permanent magnets that fall back behind the laminated core cause a reduction in magnetic flux. Known permanent magnet rotors are further restricted in their structure, especially with respect to the desired shape of the laminated core, which makes individual assembly configurations difficult. Furthermore, when an electric motor is provided to drive a fluid pump into which a medium is injected inside the motor, there is a lack of means for optimally or desirably flowing through the components. Usually, there is no means for optimally or desirably dissipating heat from the motor components.
Summary of the Invention
Problems to be Solved by the Invention
[0004] The object of the present invention is to overcome the above-mentioned drawbacks, and in particular to provide an improved permanent magnet rotor that enables an individually configurable structure and improves the way magnetic flux acts. Furthermore, it aims to efficiently dissipate heat through a medium. [Means for solving the problem]
[0005] This problem is solved by the features of claim 1.
[0006] The permanent magnet rotor has at least one laminated core, which is formed from at least two sub-cores, the laminated core having magnet housing pockets in which permanent magnets are housed, the laminated core having a housing portion in its center for a motor shaft, each sub-core being formed by stacking individual sheets, and the permanent magnets protruding from the magnet housing pockets in at least one axial direction.
[0007] The forceful flow and swirling of a medium within the motor is generated by at least one permanent magnet protruding (or projecting, or moving away from) the end face of the permanent magnet rotor in at least one axial direction (and therefore to one or both sides) from the magnet housing pocket. The protruding permanent magnet acts like an impeller in the permanent magnet rotor, resulting in the flow and swirling of the medium. This produces a defined swirling and circulating effect, similar to that of an impeller pump. This swirling effect is enhanced by the presence of passages through which the rotor laminate core passes. It is also possible for the permanent magnets to protrude on both sides. In known permanent magnet rotors where the permanent magnets terminate flush with the laminate core, the circulating effect is not possible.
[0008] Furthermore, forming fluid passages within the stator increases the fluid flow. In a wet rotor motor, it is effective to circulate the fluid surrounding the permanent magnet rotor as desired to ensure good heat dissipation from the stator and, if applicable, electrical equipment.
[0009] Preferably, all permanent magnets protrude axially on a common (radial) plane. The height to which the permanent magnets protrude or extend can be individually adapted to the assembled size of the laminate core or two sub-cores according to the desired parameters of the motor. The permanent magnet rotor can be formed as an I-rotor, T-rotor, or V-rotor, often as an IPM (Internal Permanent Magnet) rotor, or as an SPM (Surface Permanent Magnet) rotor.
[0010] The motor's back electromotive force (EMF) constant can be increased by extending the permanent magnet rotor relative to the stator length, thereby increasing the magnetic flux density and improving motor output without increasing the overall dimensions of the motor itself. Since rotor packs are often punched out together with stator packs, it is beneficial for the permanent magnet rotor and stator to have the same length (and therefore a uniform number of individual sheets within the laminate core). If the permanent magnet rotor is longer than the stator, the stator sheet will be left over and become waste during the punching process.
[0011] Nevertheless, in order to increase the magnetic flux density, in the spirit of this invention, only the magnets are formed to be longer than the laminate core. The laminate core can capture and utilize the magnetic flux of the protruding magnets. This makes it possible to increase the motor's back EMF constant while keeping the length of the laminate core of the permanent magnet rotor the same.
[0012] The motor shaft is press-fitted into the housing at the center of the laminated core after the two partial cores are joined together. The laminated core can be sprayed with plastic before or after the motor shaft is press-fitted. The plastic spraying is used to protect the laminated core from corrosion in the medium. Alternatively, the laminated core can be provided with a corrosion-resistant coating.
[0013] In the development, the individual sheet according to the first embodiment has at least one magnet housing pocket and at least one clamping tongue within the housing. The at least one clamping tongue can be flexibly oriented axially upward or downward when inserting the permanent magnet. Furthermore, the at least one clamping tongue allows the permanent magnet to be fixed in the magnet housing pocket by friction and shape coupling. For example, the permanent magnet may have grooves for shape coupling. Preferably, this fixing eliminates the need for additional substances such as adhesives. Furthermore, preferably, the cover on the axial end face of the laminate core can also be omitted, because the permanent magnet cannot fall out due to the clamping tongue. Spraying around the laminate core after insertion of the permanent magnet can also be omitted.
[0014] Particularly preferably, at least one fluid passage (and / or fluid hole) is formed within the individual sheet. The fluid passage assists the flow of the medium through the permanent magnet rotor, in which case at least one fluid passage is located away from (e.g., concentrically) the motor shaft housing and forms an axial passage within the laminate core. Additionally, at least one fluid passage is formed by the permanent magnet clearance design and at least one clamping tongue within the magnet housing pocket. Through the fluid passage and at least one fluid hole, and through the air gap between the permanent magnet rotor and the stator, the medium circulates.
[0015] In one embodiment, the individual sheet according to the second embodiment forms an uninterrupted housing at its periphery. This means that the housing does not have clamping tabs, interruptions, or protrusions. As a result, the housing of the individual sheet according to the second embodiment does not come into contact with the diameter of the shaft at its periphery. In a laminate core formed from individual sheets according to the second embodiment, the laminate core is sprayed with plastic around it after the shaft is press-fitted. Alternatively, the shaft can be fixed within the laminate core using a bonding means (e.g., adhesive).
[0016] According to other embodiments, the individual sheets according to the third embodiment form a housing having a larger radial diameter than those according to the second embodiment. This allows for the formation of certain notches within the laminate core, for example, in which a thrust disc or an additional bearing sheet can be housed.
[0017] According to the embodiment, each subcore is formed equally. Each subcore has an equal number of individual sheets based on the respective (first, second, or third) embodiment. However, instead, each subcore may have a different number of individual sheets having different embodiments.
[0018] In another preferred embodiment, each partial core is formed from a number of individual sheets based on the first embodiment.
[0019] However, it is also conceivable that each subcore be formed from a number of individual sheets based on the second embodiment.
[0020] Furthermore, it is conceivable that each subcore be formed from a number of individual sheets based on the third embodiment.
[0021] Furthermore, each partial core can be formed from a number of individual sheets based on the first and / or second and / or third embodiments.
[0022] The embodiments described above allow for the individual construction of partial cores by various combinations of individual sheets based on embodiments that can be combined as desired. This makes the laminate core individually adaptable to specific motor requirements.
[0023] In an alternative embodiment, at least one individual sheet has at least one sheet flap on at least one axial end face of the laminate core, which extends axially from the laminate core. Within the framework of this example, forced media flow and media swirling are also provided by the protruding sheet flap instead of the protruding permanent magnet, the sheet flap being formed, for example, from or to the first individual sheet during punching. One(s) sheet flaps may be provided in addition to the protruding permanent magnet, allowing for additional fixation of the protruding permanent magnet. The uppermost individual sheet may be different from the punching of the other individual sheets.
[0024] In a preferred embodiment of the present invention, a portion of the permanent magnet can be housed in a first partial core, and another portion of the permanent magnet can be housed in a second partial core, and the first and second partial cores can be combined into one or more common laminate cores. In this case, a portion of the permanent magnet is inserted into the magnet housing pocket in the punching direction of the individual sheet. This prevents the upper surface of the magnet from being damaged by the clamping tabs in the magnet housing pocket 5. When combining the partial cores, the second partial core is mounted on top of the first partial core in the punching direction, thereby avoiding damage to the permanent magnet. Another advantage of dividing the permanent magnet into two partial cores is that magnetization of the permanent magnet in each partial core is simpler. In other embodiments, it is also possible to mount all the permanent magnets in the first or second partial core and then place the other partial core on top of the magnet.
[0025] Particularly preferably, a thrust disc is mounted on the motor shaft. This thrust disc enables frictionless starting of the permanent magnet rotor and limits its axial play. In its radial dimensions, the thrust disc corresponds to (or is smaller than) the radially increasing diameter of the third embodiment already described.
[0026] In particular, this permanent magnet rotor can be applied within an electric motor. Preferably, this is a BLDC motor. However, the present invention is not limited thereto in this regard and covers all possible types of motors that can be used.
[0027] Particularly preferably, this permanent magnet rotor is applied within a fluid pump. It is also conceivable to use this permanent magnet rotor within an electric drive for a fluid pump or an actuator or a servo motor.
[0028] When the magnets are arranged in a T-shape or a V-shape, a space that is not utilized towards the center axis is created, and that space consists only of unusable sheet material. In order to reduce the component weight and improve the space utilization, cutouts can be provided at both ends of the rotor at this location. This provides space for arranging the bearing location, and a part of that bearing location protrudes into the permanent magnet rotor.
[0029] Hereinafter, the present invention will be described in detail using embodiments while referring to the attached schematic drawings. In that regard:
Brief Description of the Drawings
[0030] [Figure 1] FIG. 1 shows an electromagnetic rotor according to an embodiment in a perspective view. [Figure 2] FIG. 2 shows the electromagnetic rotor shown in FIG. 1 in a cross-section. [Figure 3] FIG. 3 shows another cross-section of the electromagnetic rotor shown in FIG. 1. [Figure 4a] FIG. 4a shows the details of an individual sheet according to the first embodiment. [Figure 4b] FIG. 4b shows the details of an individual sheet according to the second embodiment. [Figure 4c] FIG. 4c shows the details of an individual sheet according to the third embodiment. [Figure 5] FIG. 5 shows a permanent magnet rotor according to another embodiment in a perspective view. [Modes for carrying out the invention]
[0031] Figure 1 shows a perspective view of a permanent magnet rotor 1 based on one embodiment. This permanent magnet rotor 1 has at least one sheet pack (laminated core) 2, which is formed from at least two sub-packs (sub-cores) 3, 4. The laminate core 2 has magnet housing pockets 5, in which permanent magnets 6 are housed. The laminate core 2 has a housing section 7 in its center for housing a motor shaft 8. Each sub-core 3, 4 is formed by stacking individual sheets 9, and at least one permanent magnet 6 protrudes from the magnet housing pocket 5 in at least one axial direction. Each sub-core 3, 4 is formed equally. However, alternatively, each sub-core can be formed differently. A thrust disk 12 is mounted on the motor shaft 8. Alternatively, additional bearings can be mounted on the motor shaft 8.
[0032] Figure 2 shows a cross-sectional view of the permanent magnet rotor 1 shown in Figure 1. This permanent magnet rotor 1 has at least one laminate core 2, which is formed from at least two sub-cores 3, 4. The laminate core 2 has a magnet housing pocket 5, in which a permanent magnet 6 is housed. The laminate core 2 has a housing portion 7 in its center for a motor shaft 8. Each sub-core 3, 4 is formed by stacking individual sheets 9, and at least one permanent magnet 6 protrudes from the magnet housing pocket 5 in at least one axial direction. Each sub-core 3, 4 is formed equally. However, it is also possible to form each sub-core differently. A thrust disk 12 is mounted on the motor shaft 8. Alternatively, additional bearings may be mounted on the motor shaft 8. Each sub-core 3, 4 is formed from a number of individual sheets 9 according to the first (A), second (B), and third (C) embodiments. Alternatively, at least one partial core 3, 4 can be formed from a number of individual sheets (9) according to the first (A) embodiment, or according to the second (B) embodiment, or according to the third (C) embodiment. In the alternative, at least one partial core 3, 4 can be formed from a number of individual sheets 9 according to the first (A) embodiment and / or the second (B) embodiment and / or the third (C) embodiment. Thus, all conceivable combinations of the individual sheet embodiments (A to C) to form at least one partial core 3, 4 are possible. An individual sheet 9 according to the first embodiment (A) has at least one clamping tongue 10a, 10b within at least one magnet housing pocket 5 and housing section 7. At least one clamping tongue 10b clamps onto the motor shaft 8, and at least one clamping tongue 10a secures the permanent magnet 6 in the magnet housing pocket 5 by friction coupling. An individual sheet 9 according to the second (B) embodiment forms an uninterrupted housing section 7 at its periphery U. The individual sheet 9 according to the third (C) embodiment forms a housing portion 7 with a larger radial diameter than that in the second (B) embodiment.
[0033] Figure 3 shows another cross-section of the permanent magnet rotor 1 shown in Figure 1. The laminate core 2 is formed from two equally formed partial cores 3 and 4. Each partial core 3 and 4 is formed from a number of individual sheets 9 based on the first (A), second (B), and third (C) embodiments. Alternatively, at least one partial core 3 or 4 can be formed from a number of individual sheets 9 based on the first (A), second (B), or third (C) embodiment. In the alternative, at least one partial core 3 or 4 can be formed from a number of individual sheets 9 based on the first (A) and / or second (B) and / or third (C) embodiments. Thus, all conceivable combinations of embodiments (A to C) of the individual sheets 9 combined into at least one partial core 3 or 4 are possible. A portion of the permanent magnet 6 is housed in the first partial core 3, and a portion of the permanent magnet 6 is housed in the second partial core 4. The first partial core 3 and the second partial core 4 are combined into one laminate core 2. Alternatively, all permanent magnets 6 can be housed within a first or second partial core 3, 4, in which case the second partial core 4 or the first partial core 3 is slidably or press-fitted onto all the permanent magnets 6 to form a single laminate core 2.
[0034] Figures 4a–c show individual sheets 9 based on the first (A), second (B), or third (C) embodiment.
[0035] Figure 4a shows an individual sheet 9 according to the first embodiment (A), which has a housing 7 in the center for a motor shaft 8 (not shown). At least one clamping tongue 10b is formed within the housing 7, and when the motor shaft 8 is press-fitted, the clamping tongue grips the motor shaft, fixing the motor shaft 8 within the laminate core 2 (not shown) by friction and shape coupling. For example, a permanent magnet may have a groove for shape coupling. The individual sheet 9 has magnet housing pockets 5, in which a permanent magnet 6 is fixed. At least one clamping tongue 10a is provided in at least one magnet housing pocket 5, which holds the permanent magnet 6 within the magnet housing pocket 5. Within the individual sheet 9, at least one fluid passage 11 is formed in at least one magnet housing pocket 5. The individual sheet 9 shown herein is formed for a T-rotor. Alternatively, the individual sheet 9 may be formed for a V-rotor or an I-rotor, and preferably for an SPM-rotor or an IPM-rotor. In other alternatives, the individual sheet 9 itself may have at least one fluid passage 11 (not shown).
[0036] Figure 4b shows an individual sheet 9 according to a second embodiment (B), which has a housing 7 in the center for a motor shaft 8 (not shown). This housing 7 is formed without interruption at its periphery U. The individual sheet 9 has magnet housing pockets 5 in which permanent magnets 6 are fixed. At least one clamping tongue 10a is provided in at least one magnet housing pocket 5, which holds the permanent magnet 6 in the magnet housing pocket 5. At least one fluid passage 11 is formed in at least one magnet housing pocket 5 within the individual sheet 9. The individual sheet 9 shown herein is formed for a T-rotor. Alternatively, the individual sheet 9 can be formed for a V-rotor or an I-rotor, and preferably for an SPM-rotor or an IPM-rotor.
[0037] Figure 4c shows an individual sheet 9 according to the third embodiment (C), which has a central housing 7 for a motor shaft 8 (not shown). This housing 7 is formed to be larger in axial diameter than in the second embodiment (B). Also, this housing 7 is formed without interruption at its periphery (U). The larger radial diameter of the housing 7 allows for the formation of certain notches within the laminate core, for example, to accommodate a thrust disk 12 or an additional bearing sheet within these notches. Within the individual sheet 9, at least one fluid passage 11 is formed within at least one magnet housing pocket 5.
[0038] Figure 5 shows a perspective view of a permanent magnet rotor according to another embodiment. This permanent magnet rotor 1 has at least one laminate core 2, which is formed from at least two partial cores 3, 4, as in the prior example. The laminate core 2 has magnet housing pockets 5, in which permanent magnets 6 are housed. In an extension of the present invention, at least one individual sheet 9 has at least one sheet flap 13 on at least one axial front side of the laminate core 2, which extends axially from the laminate core 2. In other words, a portion of the individual sheet 9 is folded up by 90° after the die-cutting process. This sheet flap 13 can be located immediately next to the magnet housing pocket 5. There may be only one sheet flap 13, but there may be multiple sheet flaps 13 extending along the entire periphery. In the example of Figure 5, each magnet housing pocket 5 has a sheet flap on the individual sheet 9. It is conceivable to have axially projecting sheet flaps 13 on both axial end faces of the permanent magnet rotor 1. The fixing of the protruding permanent magnets and the forced flow and swirling of the media are preferably further improved. [Explanation of Symbols]
[0039] 1 Permanent magnet rotor 2. Laminated core (sheet pack) 3 partial cores 4 partial cores 5 magnetic storage pockets 6 Permanent Magnets 7. Storage area 8 motor shafts 9 individual sheets 10a Clamp tongue 10b Clamp tongue 11 Fluid hole 12 Thrust Disks 13 Seat flaps 14 End face A. First Embodiment B. Second Embodiment C Third Embodiment U-shaped periphery
Claims
1. A permanent magnet rotor (1) having at least one laminated core (2) formed from at least two partial cores (3, 4), The laminate core (2) has a magnet housing pocket (5), and a permanent magnet (6) is housed therein. The laminate core (2) has a housing portion (7) for the motor shaft (8) in its center. Each subcore (3, 4) is formed by stacking individual sheets (9), and At least one permanent magnet (6) protrudes from the magnet housing pocket (5) in at least one axial direction. Permanent magnet rotor.
2. The permanent magnet rotor according to claim 1, wherein the individual sheet (9) has at least one clamping tongue (10a, 10b) in at least one magnet housing pocket (5) and in the housing portion (7) according to the first embodiment (A).
3. The permanent magnet rotor according to claim 2, wherein at least one fluid passage (11) is formed in at least one magnet housing pocket (5) within the individual sheet (9).
4. The permanent magnet rotor according to any one of claims 1 to 3, wherein the individual sheet (9) forms the housing portion (7) on its periphery (U) without interruption based on the second embodiment (B).
5. The permanent magnet rotor according to any one of claims 1 to 4, wherein the individual sheet (9) forms the housing portion (7) with a radial diameter larger than that in the second embodiment (B), based on the third embodiment (C).
6. A permanent magnet rotor according to any one of claims 1 to 5, wherein each of the partial cores (3, 4) is equally formed.
7. A permanent magnet rotor according to any one of claims 1 to 6, wherein each partial core (3, 4) is formed from a number of individual sheets (9) according to the first embodiment (A).
8. A permanent magnet rotor according to any one of claims 1 to 7, wherein each partial core (3, 4) is formed from a number of individual sheets (9) according to the second embodiment (B).
9. A permanent magnet rotor according to any one of claims 1 to 8, wherein each partial core (3, 4) is formed from a number of individual sheets (9) according to the third embodiment (C).
10. A permanent magnet rotor according to any one of claims 1 to 9, wherein each partial core (3, 4) is formed from a number of individual sheets (9) according to the first (A) and / or second (B) and / or third (C) embodiment.
11. A permanent magnet rotor according to any one of claims 1 to 10, wherein at least one individual sheet (9) has at least one sheet flap (13) on at least one axial end face (14) of the laminate core (2) and extends axially from the laminate core (2).
12. A permanent magnet rotor according to any one of claims 1 to 11, wherein a portion of the permanent magnet (6) is housed in a first partial core (3), and a portion of the permanent magnet (6) is housed in a second partial core (4), and the first partial core (3) and the second partial core (4) are joined together as a single laminate core (2).
13. A permanent magnet rotor according to any one of claims 1 to 12, wherein a thrust disc (12) is mounted on the motor shaft (8).
14. The permanent magnet rotor (1) according to any one of claims 1 to 13, wherein the permanent magnet rotor (1) is used in an electric motor.
15. The permanent magnet rotor (1) according to any one of claims 1 to 14, wherein the permanent magnet rotor (1) is used in a fluid pump.