Rotor and motor
By setting axially extending permanent magnets on the rotor, the ohmic loss problem in the winding head area is solved, the magnetic flux and torque are increased, and the efficiency and torque density of the motor are improved.
Patent Information
- Application Number
- CN202510775340.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-06-19
- Filing Date
- 2025-06-11
- Publication Date
- 2025-12-19
Smart Images
Figure CN121173019A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present invention relates to a rotor for an electric machine and to an electric machine comprising a rotor and a stator. BACKGROUND
[0002] Electric machines have been of great importance since the industrial revolution and their role has been increasing in today's society. Electric machines play a vital role in everyday life, for example in the field of household appliances, robotics, automotive industry, aerospace, wind turbines, etc. Compared to internal combustion engines, electric machines are more efficient, less costly and simpler in design.
[0003] The two main components of an electric machine are a stator and a rotor which is mounted so as to be movable relative to the stator.
[0004] The stator and the rotor usually comprise a magnetic material. There is an air gap between the stator and the rotor. The stator usually has slots facing the air gap and distributed along a circumference. Coils of a winding are inserted into these slots. The windings are of two types, namely concentrated windings and distributed windings.
[0005] Distributed windings comprise coils which are wound around at least two teeth, respectively, and which are superimposed on each other in a winding head.
[0006] The part of the winding which protrudes in axial direction beyond the stator slots is called winding head. For concentrated windings, the coils are not superimposed in the area of the winding head, so that the structure is more compact.
[0007] In electric machines, torque is generated only in the area of the stator core, i.e. in the area of the axial length of the stator core. This axial length is therefore often referred to as the effective length of the stator. Since the winding head is located outside this effective length, this part of the winding does not contribute to the generation of torque.
[0008] On the contrary, Ohmic losses occur in the area of the winding head, which negatively affect the efficiency of the electric machine. The shorter the axial length of the electric machine due to space limitations in the application, for example, the more pronounced the above-mentioned disadvantages caused by the winding head. SUMMARY
[0009] It is therefore an object to provide a rotor and an electric machine with improved performance.
[0010] This object is achieved by the subject matter of the independent claims. Further improvements and advantageous designs are given in the dependent claims.
[0011] In one embodiment, a rotor for an electric machine is provided, the rotor comprising a rotor core and a rotor shaft. Furthermore, at least one permanent magnet is provided, which extends further in axial direction than the rotor core at least on one side.
[0012] Generally, the torque is generated only in the area of the air gap between the rotor and the stator, i.e. in the area of the effective length of the stator. However, due to the proposed principle, at least one permanent magnet extends in axial direction beyond the rotor core, so that otherwise unused space is utilized, thereby making an additional contribution to the generation of torque, thus increasing the available torque.
[0013] The portion of the stator core of the rotor which is axially located outside the stator core in the area of the winding head is no longer left unused.
[0014] The at least one permanent magnet can comprise one or more of the following types: tangential magnet, V-shaped magnet, spoke magnet.
[0015] The several permanent magnets in the rotor can be alternately magnetized to north or south poles along the circumferential portion.
[0016] In one embodiment, the at least one permanent magnet is magnetized along an axis perpendicular to the rotor axis.
[0017] In one embodiment, the at least one permanent magnet is mounted in the rotor core.
[0018] In one embodiment, the at least one permanent magnet is arranged in a magnet module, respectively. The magnet module has a greater axial length compared to the rotor core.
[0019] The magnet module increases the magnetic flux by guiding the magnetic flux from the part of the magnet outside the effective length into the area of the effective length. This further increases the torque.
[0020] In one embodiment, the axial length of the magnet module is greater than the axial length of the permanent magnet.
[0021] In one embodiment, the magnet module axially covers the permanent magnet in a plane perpendicular to the direction of magnetization.
[0022] In one embodiment, the rotor core comprises a magnetic material.
[0023] In one embodiment, the magnet module comprises a magnetic material, respectively.
[0024] The rotor core can comprise at least one of the following types: laminated core, soft magnetic composite, solid steel.
[0025] The axial length of the magnet module can be greater than or equal to the axial length of the magnet.
[0026] In one embodiment, an electric machine having a rotor and a stator as described above is disclosed.
[0027] In the proposed electric machine, the space required for the winding head of the stator in axial direction can also be utilized in the area of the stator, i.e. the torque of the electric machine is increased.
[0028] In one embodiment, the stator has slots into which coils of the electrical winding are inserted.
[0029] For example, the axial length of the at least one permanent magnet can be less than or equal to the axial length of the stator including the winding heads.
[0030] In one embodiment, the axial length of the at least one rotor module is less than or equal to the axial length of the stator including the winding heads.
[0031] The axial length of the stator and the rotor at the air gap can be the same.
[0032] The application is explained more fully with reference to the drawings, wherein several exemplary embodiments are shown. BRIEF DESCRIPTION OF DRAWINGS
[0033] In the drawings:
[0034] Figure 1 Exemplary embodiments of an electric machine according to the proposed principles are shown;
[0035] Figures 2 to 6 Exemplary embodiments of a magnet module according to the proposed principles are shown;
[0036] Figures 7 to 11 Exemplary embodiments of a rotor with tangential permanent magnets according to the proposed principles are shown;
[0037] Figure 12 Exemplary embodiments of a rotor according to the proposed principles are shown;
[0038] Figure 13 Exemplary embodiments of an electric machine according to the proposed principles are shown;
[0039] Figures 14 to 19 Exemplary embodiments of an electric machine with V-shaped magnets according to the proposed principles are shown;
[0040] Figures 20 to 23 Exemplary embodiments of an electric machine with spoke magnets according to the proposed principles are shown; and
[0041] Figures 24 to 27 Exemplary embodiments of a magnet module according to the proposed principles are shown. DETAILED DESCRIPTION
[0042] Figure 1 Exemplary embodiments of an electric machine according to the proposed principles are shown based on a cross-sectional view of a cross-section.
[0043] The motor includes a rotor 1 and a stator 2. The rotor 1 is mounted to rotate about an axis 3. Below the axis, that is, below the axis of symmetry, there is a symmetrical portion of the rotor 1 and the stator 2, but it is not shown.
[0044] The stator 2 includes a winding (not visible) that is inserted into a slot in the stator. However, the winding head 9 is visible, which is located at the end face of the stator and protrudes axially beyond the stator core 4.
[0045] The rotor 1 includes a permanent magnet 5, which extends parallel to the shaft 3 in its main direction. It can be seen that the permanent magnet 5 is longer than the rotor core 6 in the axial direction.
[0046] The permanent magnet 5 is installed in the magnet module 7, which surrounds the permanent magnet 5 in the radial and axial directions.
[0047] The stator core 4 and the rotor core 6 have the same axial length and are separated from each other by an air gap 8.
[0048] Normally, torque is generated only in the region of the air gap 8 between the rotor 1 and the stator 2, that is, in the region of the stator core 4. However, since at least one permanent magnet 5 extends beyond the rotor core 6 in the axial direction according to the proposed principle, that is, beyond the effective length of the rotor, the previously unused space is utilized, thereby making an additional contribution to the generation of torque and thus increasing the available torque.
[0049] The portion located in the region of the winding head 9, which is axially positioned outside the stator core 4 of the rotor, is no longer idle.
[0050] Magnet module 7 increases the magnetic flux by directing the magnetic flux from the portion outside the effective length of magnet 5 to the portion within the effective length. This further increases the torque.
[0051] Figure 2 An exemplary embodiment of the magnet module 7 is shown, wherein the permanent magnet 5 has not yet been inserted into the magnet module 7. It can be seen that the permanent magnet 5 has a flat, cubic geometry and is reliably fitted into the magnet module 5, which is also cubic inside and out. The arrows at the permanent magnet 5 indicate the direction of magnetization with north and south poles.
[0052] Figure 3 This shows the permanent magnet 5 after it has been inserted into the magnet module 7. Figure 2 An exemplary embodiment is provided. In this example, the magnet module includes SMC, i.e., soft magnetic composite material, or solid iron or solid steel.
[0053] Alternatively, such as Figure 4 As shown, the magnet module 71 includes laminated iron or laminated steel. Here, the laminations are oriented along the circumferential direction of the motor.
[0054] In another alternative embodiment related to Figure 3 a sandwich structure is shown instead of a cuboid magnet module, which sandwich structure comprises two flats of the magnet module 72 between which the permanent magnets 5 are located.
[0055] Figure 6 A combination of the designs of Figure 3 and Figure 5 is shown, i.e. a sandwich structure of the magnet module 73, which here comprises laminated iron.
[0056] Various exemplary embodiments of permanent magnets in the form of tangential magnets, V-shaped magnets or spoke magnets will be explained below.
[0057] Figure 7 An exemplary embodiment of permanent magnets 5 as tangential magnets in a sector of the rotor 1 is shown. Here only one rotor pole is shown. In this example, the permanent magnets 5 are surrounded by magnet modules 7, as explained by means of Figure 3 and shown in Figure 9 . For a better understanding, Figure 8 a sector of the rotor 1 in Figure 7 is shown, but without permanent magnets and magnet modules.
[0058] Figure 10 Another exemplary embodiment of permanent magnets 5 as tangential magnets in a sector of the rotor is shown. This is a variation of the design in Figure 7 but in which both the rotor core 11 and the magnet module 71 are implemented in laminated iron. Figure 11 A magnet module 71 in Figure 10 is shown, in which the tangential permanent magnets 5 have not yet been inserted, which are shown next to the magnet module 71 in the figure.
[0059] Figure 12 A perspective view of a complete rotor 1 is shown, in which the permanent magnets 5 are designed as tangential magnets based on the exemplary embodiment as described above with reference to Figures 7 to 9 . Each permanent magnet 5 is mounted in a magnet module. A total of 10 permanent magnets 5 are distributed along the circumference. It can be seen that all permanent magnets and their associated magnet modules have the same geometry and that each permanent magnet protrudes in the axial direction beyond the rotor core at both end faces of the rotor 1. The rotor 1 is also suitable for the corresponding magnet modules 7.
[0060] Figure 13 An exemplary embodiment of an electric machine according to the proposed principle is shown. In addition to the Figure 12In addition to the rotor 1, a stator 2 is also provided, which has a plurality of parallel slots distributed along the circumference, into each of which a conductor of a coil of an electrical winding is inserted. On both end faces of the stator, winding heads are clearly visible, which protrude in the axial direction beyond the stator core.
[0061] Figures 14 to 16 An exemplary embodiment of a rotor 12 with V-shaped permanent magnets 51 is shown, each of which is inserted into a magnet module 74.
[0062] Figure 14 A sector of the rotor 12 is shown. It can be seen that, as in the example described above, each permanent magnet protrudes clearly in the axial direction beyond the rotor core.
[0063] Figure 15 A sector of the rotor 12 is shown, in which the magnet modules 74 with permanent magnets 51 have not yet been inserted.
[0064] Figure 16 A sector of the rotor 12 is shown, in which the magnet modules 74 with permanent magnets 51 have been inserted into two openings of the rotor 12, respectively. Figure 15
[0065] Also, in the exemplary embodiment according to Figures 14 to 16 , the magnet modules with permanent magnets protruding in the axial length of the stator core lead to an increase in the flux density in the air gap, so that more torque is obtained.
[0066] Figure 17 and Figure 18 Another exemplary embodiment is shown, which largely corresponds to the exemplary embodiment according to Figures 14 to 16 , which is not described again here.
[0067] However, the difference is that neither the rotor 13 nor the magnet modules 75 are made of SMC or solid iron material, but rather of laminated iron. It is emphasized that the direction of the laminations of the magnet modules 75 is different from the direction of the laminations of the stator 13.
[0068] Figure 18 A magnet module 75 is shown, which is inserted into the rotor 13 in Figure 17
[0069] Figure 19 A part of the electric machine with the stator 2 and the rotor 13 as described above is shown. Also in this case, it can be seen that the magnet modules 75, which extend in the axial direction, are arranged below the winding heads 9. Here, too, the effect of an additional magnetic flux is produced, so that the torque and the torque density are higher compared to a conventional electric machine without extended magnets and without magnet modules.
[0070] Figure 20 An exemplary embodiment of an electric motor having a stator 2 and a rotor 14 is shown, which are located in a sector. This exemplary embodiment largely corresponds to... Figure 19 The embodiment differs from the one provided in that it does not provide a V-shaped magnet, but instead uses a spoke magnet 52, each spoke magnet 52 having an associated magnet module 76.
[0071] It can be seen that the proposed principle and its advantages are also applicable to spoke magnets in rotors.
[0072] Figure 21 The rotor 14 is shown relative to Figure 20 In another embodiment, the rotor 14 is designed here as a rotor 15 with laminated iron. The magnet module 77 of the spoke magnet 52 is also made of laminated iron.
[0073] Figure 20 and Figure 21 Parts of rotors 14 and 15 with spoked magnets, based on the proposed principle, are shown respectively. Figure 22 and Figure 23 Exemplary embodiments of a rotor 14 with six magnet modules 76 and a rotor 15 with six magnet modules 77 are shown, each of the six magnet modules 76 and 77 having a spoke magnet.
[0074] Figure 24 An exemplary embodiment of the magnet module 7 is shown, wherein the permanent magnet 52 has not yet been inserted into the magnet module 7. It can be seen that, as according to... Figure 2 In the example, permanent magnet 52 has a flat, cubic geometry and is reliably assembled into magnet module 7, which is also cubic inside and out. Arrows at permanent magnet 52 indicate the direction of magnetization with north and south poles. (Compared to...) Figure 2 Compared to other designs, the permanent magnet comprises several partial magnets made of different materials. In the central region, the permanent magnet 52 includes a cubic partial magnet 53 made of a first material such as NdFeB, i.e., neodymium iron boron. In each axial direction, a partial magnet 54 made of a second material, which in this example is ferrite, adjoins the face of the central region 53. All regions together form the permanent magnet 52.
[0075] Figure 25 This shows the permanent magnet 52 after it has been inserted into the magnet module 7. Figure 24 An exemplary embodiment of the invention.
[0076] Figure 26 An exemplary embodiment of the magnet module 7 is shown, wherein the permanent magnet 55 has not yet been inserted into the magnet module 7. It can be seen that, as according to... Figure 2In the example of Fig. 5, the permanent magnet 55 has a flat cuboid geometry and fits reliably into the magnet module 7, which is also cuboid. The arrow at the permanent magnet 55 indicates the direction of magnetization with north and south poles. In contrast to the design according to Figure 2 The permanent magnet comprises several partial magnets with different materials, the permanent magnet 55 having two cuboid portions, the faces of which adjoin one another in the axial direction. One half of the permanent magnet 55 comprises a first magnetic material, which is NdFeB here, and forms a first partial magnet 56, while the other half of the permanent magnet comprises a second material, which is a ferrite magnet here, and forms a second partial magnet 57.
[0077] Figure 27 Fig. 5 shows the permanent magnet 55 after insertion into the magnet module 7 in an exemplary embodiment of the application. Figure 25
[0078] List of reference signs
[0079] 1 rotor
[0080] 2 stator
[0081] 3 axis
[0082] 4 stator core
[0083] 5 permanent magnet
[0084] 51 permanent magnet
[0085] 52 permanent magnet
[0086] 6 rotor core
[0087] 7 magnet module
[0088] 8 air gap
[0089] 9 winding head
[0090] 11 rotor
[0091] 12 rotor
[0092] 13 rotor
[0093] 14 rotor
[0094] 15 rotor
[0095] 51 permanent magnet
[0096] 52 permanent magnet
[0097] 53 partial magnet
[0098] 54 partial magnet
[0099] 55 permanent magnet
[0100] 56 partial magnet
[0101] 57 partial magnet
[0102] 71 magnet module
[0103] 72 magnet module
[0104] 73 magnet module
[0105] 74 magnet module
[0106] 75 magnet module
[0107] 76 magnet module
[0108] 77 magnet module
Claims
1. A rotor (1) for an electric motor, the rotor (1) comprising: - Rotor core (6) and rotor shaft (3); as well as - At least one permanent magnet (5), wherein the at least one permanent magnet (5) extends along the main axial direction, and the axial length of the at least one permanent magnet (5) is greater than the axial length of the rotor core (6). - wherein at least one permanent magnet (5) is respectively disposed in the magnet module (7); and - Compared to the rotor core (6), the magnet module (7) has a larger axial length.
2. The rotor according to claim 1, wherein, The rotor core (6) and / or the magnet module (7) comprise magnetic materials.
3. The rotor according to claim 1, wherein, The at least one permanent magnet (5) includes one of the following types: tangential magnet, V-shaped magnet (51), and spoke magnet (52).
4. The rotor according to claim 1, wherein, The rotor core (6) and / or the magnet module (7) include at least one of the following types: laminated iron core, soft magnetic composite material, and solid steel.
5. The rotor according to claim 1, wherein, The magnet module (71) includes laminated iron, the lamination direction of which is perpendicular to the magnetization direction of the magnet (5) and perpendicular to the lamination direction of the rotor core (11).
6. The rotor according to claim 1, wherein, The permanent magnet (52) includes several partial magnets (53, 54) made of different materials.
7. An electric motor comprising a rotor (1) and a stator (2) according to any one of the preceding claims.
8. The motor according to claim 7, wherein, The stator includes slots into which the coils of the electrical windings are inserted. The stator includes a winding head (9) on each end face. The axial length of the permanent magnet (5) or the axial length of the magnet module (7) corresponds to the axial length of the stator with the winding head (9).