Rotor of an electric machine, and electric machine

Abstract

The present invention relates to a rotor (1) of an electric machine (10), wherein the rotor (1) is designed to rotate about a rotor axis (100), the rotor (1) having a rotor main body (2) with a plurality of pole recesses (3) pointing radially outwards with respect to the rotor axis (100), and a plurality of separate pole segment bodies (4) for axial insertion into the pole recesses (3), wherein the pole segment bodies (4) each comprise: a flux-conducting body (5), a V-shaped magnetic layer which is arranged radially inside the flux-conducting body (5) and comprises at least two permanent magnets (6), and a potting compound (7) which connects the flux-conducting body (5) and the magnetic layer to form a component, and is in particular made of plastic, characterized in that the pole segment body (4) has a form-fitting contour (8) which is provided for interlockingly interacting with a mating contour (9) of the pole recesses (3) and is formed at least in sections by the potting compound (7).

Description

[0001] R.415164

[0002] Description

[0003] title

[0004] Rotor of an electric machine and electric machine

[0005] State of the art

[0006] The present invention relates to a rotor of an electric machine. The invention also relates to an electric machine with such a rotor. The rotor, in particular, comprises separate pole segment bodies that can be inserted into a rotor base body.

[0007] Prior art reveals methods for preventing magnetic flux losses. For example, document US 2023 / 0179045 A1 discloses an electric motor with a rotor mounted coaxially on a shaft. The rotor comprises a central laminated core with recesses along its outer circumference in which separate pole pieces are arranged. The pole pieces are attached to several magnets. The magnets can be positioned between the pole pieces and the laminated core. The described rotor components are encased in a wound fiber sheath. By eliminating metal connections between the pole pieces and the laminated core, magnetic leakage fluxes are minimized.

[0008] Disclosure of the invention

[0009] The rotor of an electric machine according to the invention has, on the one hand, an optimized magnetic flux, and on the other hand, the rotor is stably designed and simple and inexpensive to manufacture. This is achieved in particular by the construction of pole segment bodies that can be inserted into pole recesses of a rotor base body. R.415164

[0010] - 2 -

[0011] The rotor of an electric machine is designed to rotate a rotor axis. The rotor comprises a rotor body and a plurality of separate pole segment bodies. The rotor body is designed with several pole recesses extending radially outwards with respect to the rotor axis. The pole recesses are thus open outwards in the radial direction with respect to the rotor axis. The plurality of separate pole segment bodies are designed for axial insertion into the pole recesses, i.e., for insertion in the axial direction with respect to the rotor axis. It is provided that each pole segment body can be inserted into a single pole recess.

[0012] Each pole segment body comprises a flux guide, which is designed in particular as an insert. Furthermore, each pole segment body includes a radially arranged V-shaped magnet layer within the flux guide, comprising at least two permanent magnets. Each pole segment body also features a potting compound, made of plastic, which bonds the flux guide and the magnet layer into a single component. Thus, the pole segment body can be handled as a unit and, in particular, inserted into the rotor body as a single part. The pole segment body can therefore be inserted into the respective pole recess easily and with minimal effort.

[0013] It is also provided that the pole segment body has a positive-locking contour. This positive-locking contour serves to engage positively with a mating contour of the pole recesses. In particular, the positive-locking contour serves to engage positively with the pole recess into which the pole segment body is inserted. The positive-locking contour is preferably formed, at least partially, by the casting compound.

[0014] The positive locking mechanism between the pole recess and the pole segment body acts particularly in the radial direction with respect to the rotor axis. This results in a reliable retention of the pole segment bodies on the rotor base body. A metallic connection between the pole segment body and the rotor base body is preferably avoided, which is advantageous with regard to the magnetic flux in an electric machine with the described rotor. R.415164

[0015] - 3 -

[0016] The dependent claims describe preferred embodiments of the invention.

[0017] Preferably, the pole recesses each have V-shaped base surfaces for interaction with a V-shaped underside of the respective pole segment body. Thus, the shape of the pole recesses follows the shape of the magnet layer. This advantageously achieves an optimal separation of the rotor into a magnetically active section and a purely power transmission and support section. Furthermore, the connection between the pole recesses and the pole segment bodies is optimally designed.

[0018] The positive-locking contour of the pole segment body preferably has at least one projection. This projection engages in a recess of the pole recess to form the positive lock. In this case, the recess is the mating contour. Alternatively or additionally, the positive-locking contour of the pole segment body preferably has at least one recess. This recess engages in a projection of the pole recess to form the positive lock. In this case, the projection is the mating contour. Thus, a positive lock is formed in a simple manner, enabling force transmission in the radial direction with respect to the rotor axis. This ensures that the respective pole segment body is reliably held within the pole recess, even when the rotor is rotating during operation of the electric machine.

[0019] The flux guide is preferably a laminated core made of stacked laminations. Alternatively or additionally, the flux guide is preferably a component made of soft magnetic composite, abbreviated SMC, so that the component is also called an SMC component. This ensures optimal magnetic flux within the flux guide. An electric machine with the described rotor can therefore be used effectively.

[0020] Preferably, the flux guide body has at least one positioning projection. Particularly advantageously, the flux guide body has several positioning projections. The at least one positioning projection is designed to engage with the at least two permanent magnets of the pole segment body. This positions the at least two permanent magnets relative to the flux guide body. The permanent magnets can thus be optimally aligned and arranged. R.415164

[0021] - 4 -

[0022] The rotor body preferably has radially extending web areas between the pole recesses. A radial outer surface of the web areas, together with the respective radial outer surfaces of the pole segment bodies, defines a radial outer contour of the rotor. The pole segment bodies are therefore optimally held in the rotor body. The rotor body, together with the web areas, preferably forms a separation between the individual rotor poles.

[0023] The rotor body and the pole segment bodies are preferably surrounded circumferentially with respect to the rotor axis by a bandage. The bandage is preferably a fiber wrapping, for example based on carbon fibers. The fibers are particularly embedded in a matrix such as a polymer matrix. The bandage improves the rotor's strength, especially at high rotational speeds.

[0024] Preferably, the rotor body has layers of sheet metal stacked one above the other in the axial direction. These layers are formed by several sheet metal lamellae or by at least one sheet metal strip wound helically around the rotor axis. Using a helically wound sheet metal strip simplifies the manufacture of the rotor body. For example, only one such strip needs to be produced by stamping and wound, which results in particularly low scrap costs for the stamping process. The sheet metal lamellae or the wound sheet metal strip preferably has recesses that, after stacking the lamellae or winding the sheet metal strip, form the pole recesses.

[0025] The rotor body has through-holes in the axial direction with respect to the rotor axis. Fasteners for axially holding the sheet metal layers together and / or for attaching a cover plate to the rotor body are arranged in these through-holes. These fasteners include, for example, rivets and / or screws and / or tie rods. The use of a cover plate reduces the amount of material required for the rotor body, as it no longer needs to extend to the rotor shaft. Furthermore, the material of the cover plate and the rotor body can be optimally designed for the specific application. This results in, among other things, a

[0026] -5 -

[0027] The durability of the rotor is improved, while the rotor can be manufactured cost-effectively.

[0028] The cover plate is particularly advantageously arranged at the end face of the rotor body and designed to transmit torque to a rotor shaft. The cover plate thus serves to transmit power between the permanent magnets in the pole segment bodies and the rotor shaft. Since the cover plate plays only a minor role in the magnetic flux, it can be designed primarily for the purpose of pure power transmission.

[0029] The cover plate preferably has a shaft opening for connection to a rotor shaft. The shaft opening serves in particular to accommodate a rotor shaft that can be inserted into the cover plate. The shaft opening preferably forms a shaft-hub connection. The shaft opening can, for example, have teeth or similar features to create a positive fit and / or be designed to create a press fit. Alternatively, the shaft opening can also be designed for a material-bonded connection with the rotor shaft.

[0030] The cover plate also preferably has a circumferential contour facing away from the rotor shaft, which is particularly wave-shaped or tooth-shaped. This circumferential contour extends radially, in particular, within the magnet layers. In other words, the circumferential contour does not extend radially into the magnet layers with respect to the rotor axis, so that the magnetic flux is not, or at least only minimally, affected by the cover plate. The wave-shaped or tooth-shaped circumferential contour particularly allows the cover plate to be fastened between adjacent pole segment bodies.

[0031] Preferably, through-holes in the rotor body are arranged circumferentially with respect to the rotor axis, each between two adjacent pole recesses. This is where the greatest material accumulation of the rotor body is located, thus ensuring reliable retention of the sheet metal layers of the rotor body and reliable retention of the cover plate on the rotor body. R.415164

[0032] - 6 -

[0033] In particular, multiple alternating connecting elements are arranged circumferentially, serving solely to axially hold the sheet metal layers together, while second connecting elements are used to attach the cover plate. This allows the sheet metal layers to be connected independently of the cover plate, simplifying the handling of the rotor body during rotor assembly. The rotor body can thus be pre-assembled as a whole, with the cover plate being attached in a subsequent step. Preferably, shorter first connecting elements are provided for holding the sheet metal layers together; these do not protrude beyond the sheet metal layers in the axial direction with respect to the rotor axis. The second connecting elements are longer to protrude beyond the sheet metal layers in the axial direction with respect to the rotor axis for attachment to the cover plate.

[0034] In an alternative embodiment, all connecting elements are designed to attach the cover plate. This improves the hold of the cover plate to the rotor body.

[0035] Preferably, at least one cooling channel is formed between the pole segment body and the pole recesses. The cooling channel extends axially through the rotor. To form the cooling channel, the potting compound and / or the rotor base body have a groove-shaped recess. When the rotor base body and the pole segment body are in contact with each other, these recesses form the cooling channel. This provides a simple and reliable way to cool the permanent magnets.

[0036] The invention also relates to an electric machine. The electric machine is, for example, a permanent magnet synchronous machine. The electric machine has a rotor as described above. Furthermore, the electric machine has a stator. The stator is designed to drive the rotor and preferably has an electrical winding. R.415164

[0037] - 7 -

[0038] Further preferred

[0039] Brief description of the drawings

[0040] Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawings. The drawing shows:

[0041] Figure 1 is a schematic illustration of an electrical machine according to an embodiment of the invention,

[0042] Figure 2 is a schematic illustration of part of a rotor of the electric machine according to the exemplary embodiment.

[0043] Figure 3 shows a schematic view of a rotor body of the rotor of the electric machine according to the exemplary embodiment.

[0044] Figure 4 shows a schematic view of a pole segment body of the electric machine according to the exemplary embodiment.

[0045] Figure 5 shows a schematic view of an alternative shaft mounting of the rotor of the electric machine according to the exemplary embodiment, and

[0046] Figure 6 shows a schematic view of the rotor of the electric machine according to the embodiment with a bandage.

[0047] Embodiments of the invention

[0048] Preferably, all identical components, elements and / or units in all figures are provided with the same reference numerals.

[0049] Figure 1 schematically shows an electric machine 10 according to an embodiment of the invention. The electric machine 10 has a rotor 1 and a stator 11, wherein the rotor 1 can be driven by the stator 11. The rotor 1 is formed around a rotor axis 100, wherein the rotor axis 100 is a central axis and axis of rotation of the rotor 1 as well as a central axis of the stator 11. The electric machine 10 is R.415164

[0050] - 8 -

[0051] For example, a permanent magnet synchronous machine. Along the rotor axis 100, an axial direction 300 is defined, and perpendicular to this, a radial direction 200 is defined.

[0052] The rotor 1 has a rotor base 2 that can be connected to a rotor shaft 17, into which a plurality of pole segment bodies 4 are inserted. Each pole segment body 4 has permanent magnets 6 connected to a flux guide 5. By using the rotor base 2 on the one hand and the pole segment bodies 4 on the other, the components relevant for the magnetic flux can be separated from those solely responsible for supporting the magnets and transmitting power to the rotor shaft 17, and thus designed separately. This allows for optimal design of the corresponding components of the rotor 1, while also enabling the rotor 1 to be manufactured simply and cost-effectively. The exact construction is described with reference to the following figures.

[0053] Figure 2 schematically shows a detailed view of part of the rotor 1 of the electric machine 10 according to the embodiment of the invention. As previously described, the rotor 1 has a rotor base body 2, which is shown schematically in Figure 3. The rotor base body 2 has several pole recesses 3 extending radially outwards with respect to the rotor axis 100. The pole recesses 3 are thus open outwards in the radial direction 200. Separate pole segment bodies 4 are inserted into the pole recesses 3. The separate pole segment bodies 4 are inserted in the axial direction 300, with the pole segment bodies 4 preferably having a positive fit with the pole recesses 3 in the radial direction 200. The pole segment bodies 4 are shown schematically in Figure 4. Figures 2, 3, and 4 are described together below.

[0054] The pole segment bodies 4, which can be inserted into the pole recesses 3, each comprise a flux guide body 5, a magnet layer and a potting compound 7. The flux guide body 5 is, for example, a laminated stack of stacked sheet metal lamellae and / or a component made of soft magnetic composite.

[0055] In this embodiment, the magnet layer is V-shaped and arranged radially within the pole segment body. The magnet layer comprises, in particular, two V-shaped permanent magnets 6. R.415164

[0056] - 9 -

[0057] The potting compound 7 is designed to bond the flux guide 5 and the permanent magnets 6 of the magnet layer into a single component. The potting compound 7 is primarily made of plastic. Each pole segment body 4 can thus be handled as a unit, simplifying the assembly of the rotor 1. The respective pole segment bodies 4 can be easily inserted into the pole recesses 3. The pole recesses 3 each have V-shaped base surfaces for interaction with a V-shaped underside of the respective pole segment body 4.

[0058] To hold the pole segment bodies 4 in the pole recesses 3, each pole segment body 4 has a positive-locking contour 8. The positive-locking contour 8 serves for positive interaction with a counter contour 9 of the pole recesses 3 and is formed, at least partially, by the potting compound 7. By forming the positive-locking contour 8 with the potting compound 7, the latter can be produced simply and cost-effectively. In the illustrated embodiment, the positive-locking contour 8 of the pole segment body 4 has at least one projection that engages in a recess of the pole recess 3 to form the positive lock. In this case, the recess is the counter contour 9.

[0059] The flux guide body 5 has several positioning projections 12. The positioning projections are designed to engage with the permanent magnets 6 of the pole segment body 4. In this way, the permanent magnets 6 can be positioned relative to the flux guide body 5. Precise and reliable orientation of the permanent magnets 6 during operation of the electric machine 10 is achieved.

[0060] The rotor body 2 has radially extending web areas 13 between the pole recesses 3. A radial outer surface 13a of the web areas 13, together with the respective radial outer surfaces 4a of the pole segment bodies, defines a radial outer contour of the rotor 1. Additionally, a bandage may be provided, as will be explained later.

[0061] The rotor 1 can have cooling channels 18 (see Figure 6) extending axially 300 through the rotor 1. Figure 2 does not show any cooling channels, while Figures 3 and 4 show groove-shaped recesses 18a, 18b in the potting compound 7 and the rotor body 2. These groove-shaped

[0062] - 10 -

[0063] Recesses 18a, 18b work together when the pole segment bodies 4 are inserted to form said cooling channels 18.

[0064] The rotor body 2 has 200 stacked sheet metal layers in the axial direction. The sheet metal layers are formed by several sheet metal lamellae or by at least one sheet metal strip wound helically around the rotor axis 100. A cover plate 16 is provided to couple the rotor body 2 to the rotor shaft 17.

[0065] The rotor body 2 also has through-openings 14 in the axial direction 300 with respect to the rotor axis 100, in which first connecting elements 15a for axially holding the sheet metal layers together and second connecting elements 15b for attaching the cover plate 16 to the rotor body 2 are arranged. In the illustrated embodiment, the connecting elements 15a, 15b are rivets, but these can also be screws and / or tie rods or similar.

[0066] The through-holes 14 are arranged in the rotor body 2 in the circumferential direction 400, each between two adjacent pole recesses 3. In the illustrated embodiment, first connecting elements 15a and second connecting elements 15b are arranged in multiple alternating positions in the circumferential direction 400. Thus, the axial holding of the sheet metal layers and the fastening of the cover plate 16 are performed in multiple alternating positions. This design allows the rotor body to be handled as a unit, since the sheet metal layers are held together by the first connecting elements 15a. This simplifies the assembly of the cover plate 16. The use of the second connecting elements 15b not only holds the sheet metal layers of the rotor body 2 together, but also fastens the cover plate 16 to the rotor body 2. The second connecting elements 15b are therefore longer than the first connecting elements 15a.Alternatively, all connecting elements 15a, 15b could also be designed to fasten the cover plate 16.

[0067] The cover disk 16 has a circumferential contour facing away from the rotor shaft, which in the illustrated embodiment is shaped like a wave. The circumferential contour extends in the radial direction 200 within the magnet layers and therefore does not reach the R.415164 in the radial direction 200.

[0068] - 11 -

[0069] Permanent magnets 6 are attached. As a result, the magnetic properties of the rotor 1 are not, or only minimally, affected by the cover plate 16. The cover plate 16 is therefore designed solely as a power transmission element.

[0070] The cover plate 16 is arranged on the end face of the rotor body 2 and is designed to transmit torque to the rotor shaft 17. For connection to the rotor shaft 17, the cover plate 16 has a shaft opening 17a, 17b. The shaft opening 17a, 17b can be configured differently. For example, Figure 2 shows a first shaft opening 17a, which can create a positive-locking connection with the rotor shaft 17. An alternative is shown in Figure 5. Here, the cover plate 16 has a second shaft opening 17b, which is designed for a material-locking connection with a rotor shaft 17 and / or for creating a press fit with the rotor shaft 17. The advantage of using the cover plate 16 is that it is easily replaceable and therefore independent of the rotor body 2. This allows the rotor 1 to be optimally adapted to a required shaft-hub connection.

[0071] Figure 6 schematically shows a portion of the rotor 1 of the electric machine according to an embodiment of the invention, wherein a bandage 12 is provided. The bandage extends circumferentially 400 around the rotor axis 100, such that the rotor body 2 and the pole segment bodies 4 are surrounded by the bandage 12 in the circumferential direction 400. The bandage is, in particular, a fiber-reinforced composite material based on carbon fibers, which is wound around the rotor body 2 with the inserted pole segment bodies 4. The bandage increases the rotational speed stability of the rotor 1.

[0072] Figure 6 also shows the cooling channels 18, which are formed by the groove-shaped recesses 18a and 18b. The cooling channels 18 extend between the permanent magnets 6 in the axial direction 300 through the rotor 1. The cooling channels 18 are formed between the respective pole segment body 4 and the respective pole recesses 3. Effective cooling of the permanent magnets 6 is thus achieved.

Claims

R.415164 - 12 - Claims 1. Rotor (1) of an electric machine (10), wherein the rotor (1) is configured to rotate about a rotor axis (100), the rotor (1) having • a rotor body (2) with several pole recesses (3) pointing radially outwards with respect to the rotor axis (100), and • a plurality of separate pole segment bodies (4) for axial insertion into the pole recesses (3), wherein the polar segment bodies (4) each comprise: • a flow guide (5), • a V-shaped magnet layer arranged radially within the flux guide body (5), comprising at least two permanent magnets (6), and • a potting compound (7) that joins the flux guide body (5) and the magnet layer to form a component and is in particular made of plastic, characterized in that the pole segment body (4) has a form-fitting contour (8) which is provided for form-fitting interaction with a counter contour (9) of the pole recesses (3) and is formed at least partially by the casting compound (7).

2. Rotor (1) according to claim 1, characterized in that the pole recesses (3) each have V-shaped base surfaces for interaction with a V-shaped underside of the respective pole segment body (4).

3. Rotor (1) according to one of the preceding claims, characterized in that the positive locking contour (8) of the pole segment body (4) has at least one projection which engages in a recess of the pole recess (3), which is the counter contour (9), to form the positive locking, and / or the positive locking contour (8) of the pole segment body (4) has at least one recess into which a projection of the pole recess (3), which is the counter contour (9), engages to form the positive locking. R.415164 - 13 - 4. Rotor (1) according to one of the preceding claims, characterized in that the flux guide body (5) is a laminated core made of stacked laminated sheets and / or a component made of soft magnetic composite.

5. Rotor (1) according to one of the preceding claims, characterized in that the flux guide body (5) has at least one positioning projection (12), in particular several positioning projections (12), which is designed to be positioned against the at least two permanent magnets (6) of the pole segment body (4) in order to position the at least two permanent magnets (6) relative to the flux guide body (5).

6. Rotor (1) according to one of the preceding claims, characterized in that the rotor base body (2) has web areas (13) extending radially (200) between the pole recesses (3), wherein a radial outer surface (13a) of the web areas (13) together with respective radial outer surfaces (4a) of the pole segment bodies (4) defines a radial outer contour of the rotor (1).

7. Rotor (1) according to one of the preceding claims, characterized in that the rotor base body (2) and the pole segment bodies (4) are surrounded in the circumferential direction (400) with respect to the rotor axis (100) by a bandage (12).

8. Rotor (1) according to one of the preceding claims, characterized in that the rotor base body (2) has sheet metal layers arranged one above the other in the axial direction (200), wherein the sheet metal layers are formed by several sheet metal lamellae or by at least one sheet metal strip wound helically around the rotor axis (100).

9. Rotor (1) according to one of the preceding claims, characterized in that the rotor base body (2) has through openings (14) in the axial direction (300) with respect to the rotor axis (100), in which connecting elements (15a, 15b), in particular rivets and / or screws and / or tie rods, are arranged for axially holding the sheet layers together and / or for attaching a cover plate (16) to the rotor base body (2). R.415164 - 14 - 10. Rotor (1) according to claim 9, characterized in that the cover disk (16) is arranged at the end face of the rotor base body (2) and is designed for transmitting torque to a rotor shaft.

11. Rotor (1) according to claim 9 or 10, characterized in that the cover disk (16) has a shaft opening (17a, 17b) for connection to a rotor shaft.

12. Rotor (1 ) according to one of claims 9 to 11 , characterized in that the cover disk (16) has a circumferential contour facing away from the rotor shaft, which is in particular shaped in a wave-like or tooth-like manner and extends in a radial direction (200) in particular within the magnet layers.

13. Rotor (1) according to one of claims 9 to 12, characterized in that the through-openings (14) in the rotor base body (2) are arranged in the circumferential direction (400) with respect to the rotor axis (100) between two adjacent pole recesses (3).

14. Rotor (1) according to one of claims 9 to 13, characterized in that first connecting elements (15a) are arranged in a multiple alternating circumferential direction (400) solely for axially holding together the sheet layers and second connecting elements (15b) for fastening the cover plate (16).

15. Rotor (1) according to one of claims 9 to 13, characterized in that all connecting elements (15a, 15b) are designed to fasten the cover plate (16).

16. Rotor (1) according to one of the preceding claims, characterized in that at least one cooling channel (18) is formed between the pole segment body (4) and the pole recesses (3), which extends in the axial direction (400) through the rotor (1), wherein in particular the potting compound (7) and / or the rotor base body (2) have a groove-shaped recess (18a, 18b) for forming the cooling channel (18). R.415164 - 15 - 17. Electric machine (10) comprising a rotor (1) according to one of the preceding claims and a stator (11) designed to drive the rotor (1).

Images