Rotor of an electric machine
Patent Information
- Application Number
- EP2023709962
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-03-30
- Filing Date
- 2023-03-06
- Publication Date
- 2025-02-05
AI Technical Summary
The existing rotor designs for electrical machines require high-strength, expensive fibers for magnet fixation, which are not yet firmly connected by a plastic matrix, leading to high production costs and time-consuming processes due to separate winding for each rotor, and result in less resilient clamping and potential magnet damage.
The rotor design features multiple base bodies arranged circumferentially with radial separation to allow for magnet clamping between the rotor carrier and sleeve, using an oversize rotor carrier or tensioned winding to generate preload, reducing manufacturing costs and preventing magnet damage, while enabling higher speeds and torque transmission.
This design simplifies magnet clamping, achieves higher preloads, reduces deformations, and allows for higher speeds, lower manufacturing costs, and improved magnet cooling, while maintaining or reducing magnetic flux resistance and increasing torque capacity.
Smart Images
Figure 1.1
Abstract
Description
[0001] Description
[0002] title
[0003] Rotor of an electrical machine
[0004] State of the art
[0005] The invention is based on a rotor of an electrical machine according to the preamble of the main claim.
[0006] A rotor of an electrical machine is already known from WO 2021 / 225902 A1, comprising a rotor carrier rotatable about a rotor axis, in particular a rotor shaft, a rotor sleeve designed as a fiber composite sleeve and a rotor body arranged between the rotor carrier and the rotor sleeve, which rotor body comprises a plurality of rotor poles and at least one magnet pocket per rotor pole for receiving magnets, in particular permanent magnets, wherein the rotor body has a base body supported on the rotor carrier radially inside the magnet pockets with respect to the rotor axis and outer segment bodies radially outside the magnet pockets.
[0007] The magnets located in the magnet pockets can be clamped radially between the respective outer segment body and the base body for fixation by winding the fibers of the fiber composite sleeve onto the rotor body under tensile stress. This process requires comparatively high-strength fibers, which are comparatively expensive because the fibers are not yet firmly bonded by a plastic matrix during winding and are therefore less resilient. Furthermore, the production of such a fiber composite sleeve is comparatively time-consuming and expensive, since the winding is done separately for each rotor.
[0008] Advantages of the invention
[0009] The rotor of an electric machine according to the invention with the characterizing features of the main claim has the advantage that the clamping of the magnets in the magnet pockets is simplified in terms of manufacturing technology. A further advantage is that higher preloads can be achieved in the rotor sleeve, which results in less deformation on the outer circumference of the rotor under high-speed load, thus enabling higher rotor speeds.
[0010] These advantages can be achieved according to the invention by providing a plurality of base bodies arranged one behind the other in the circumferential direction, by forming a radial separation that is continuous in the radial direction between adjacent base bodies in the region radially inside the respective magnet pocket to enable radial displacement of the base bodies, and by clamping the base bodies between the rotor carrier and the rotor sleeve in order to clamp the magnets in the magnet pockets, in particular by means of an oversize of the rotor carrier according to a first embodiment variant or by winding the rotor sleeve under tensile stress according to a second embodiment variant.
[0011] According to the first embodiment, when the rotor carrier is inserted into the rotor body, the base bodies are displaced radially toward the rotor sleeve due to an excess of the rotor carrier, so that a deformation of the rotor sleeve creates a preload in the rotor sleeve, which leads to clamping of the magnets in the magnet pockets. Since the clamping of the magnets in the magnet pockets takes place subsequently after the magnets have been inserted into the magnet pockets, damage to the magnets, in particular to a coating of the magnets, is avoided when the magnets are inserted into the magnet pockets. Furthermore, according to the invention, very small air gaps can be achieved between the respective magnet pocket of the rotor body and the respective magnet.
[0012] The measures listed in the subclaims enable advantageous further developments and improvements of the rotor of an electrical machine specified in the main claim.
[0013] According to the advantageous first embodiment, the rotor carrier is inserted into the rotor with axial compression such that the base bodies are each displaced radially while widening the radial separations, thereby achieving preload in the rotor sleeve and consequently clamping the magnets in the magnet pockets. In this way, the rotor sleeve can be a prefabricated fiber composite sleeve into which the base bodies, the outer segment bodies, and the magnets can be inserted with a clearance fit and in which preload can be subsequently generated by means of the rotor carrier. A rotor sleeve prefabricated independently of the individual rotor has the advantage that it can be manufactured with a length many times that of the rotor and subsequently divided into several rotor sleeves. This can reduce the manufacturing costs of the rotor.
[0014] It is particularly advantageous if adjacent base bodies, according to a first embodiment, each have flat, spaced-apart separating surfaces to form the respective radial separation. In this way, a continuous separating slot in the axial and radial directions is formed between adjacent base bodies in the region radially inside the respective magnetic pocket. The first embodiment has the advantage that the rotor is easy to manufacture. Furthermore, the first embodiment has the minor disadvantage that the radial separation slightly increases the magnetic flux resistance in the respective rotor pole.
[0015] It is further advantageous if, according to a second embodiment, adjacent base bodies each have a separation interface to form the respective radial separation, wherein the respective separation interface is formed by the adjacent base bodies interlocking with each other by overlapping sheet metal segments. The second embodiment has the advantage that the disadvantageous increase in the magnetic flux resistance in the respective rotor pole is at least reduced by axially bridging the respective radial separation of the base bodies.
[0016] It is very advantageous if at least one, in particular each, of the base bodies has a shaped contour on its inner circumference for transmitting torque, in particular a projection or a recess, which interacts, in particular in a form-fitting manner, with a corresponding counter-shaped contour of the rotor carrier. In this way, the rotor can transmit a higher maximum torque, especially at high speeds.
[0017] It is also advantageous if a magnetic cooling channel is provided in each of the magnet pockets to cool the magnets. This channel is fluidly connected to a cooling channel formed in the rotor carrier via a separating slot formed by the respective radial separation. This improves the cooling of the magnets located in the magnetic pockets.
[0018] It is also advantageous if the outer segment bodies and the base bodies are connected to each other by means of bridge webs located on the outer circumference of the rotor body, or if they are each designed as separate laminated cores. Connecting the outer segment bodies and the base bodies via the bridge webs facilitates rotor production, as assembly work is reduced. The bridge webs are deformed when the base bodies are radially displaced.
[0019] Furthermore, it is advantageous if the rotor body according to a first embodiment is formed by a package of circular sheet metal laminations, wherein the sheet metal laminations each have slots for producing the radial separation of the base bodies.
[0020] It is advantageous if the rotor body according to a second embodiment is formed by a flat package of contoured sheet metal strips, wherein the contoured sheet metal strips each comprise first sheet metal segments for forming the outer segment bodies and second sheet metal segments for forming the base bodies, wherein the sheet metal segments of the respective contoured sheet metal strip are connected to one another by means of the bridge webs, wherein the flat package is bent around the rotor carrier, wherein the ends of the flat package of contoured sheet metal strips lie adjacent to one another in the circumferential direction. In this way, the manufacturing costs can be reduced, since the sheet metal waste when cutting out the contoured sheet metal strips can be significantly reduced, especially if the stator is manufactured in a similar linearly developed manner.
[0021] It is also advantageous if the rotor body according to a third embodiment is formed by spirally or helically rolling a contoured sheet metal strip edgewise around the rotor carrier, wherein the contoured sheet metal strip comprises first sheet metal segments for forming the outer segment bodies and second sheet metal segments for forming the base bodies, wherein the sheet metal segments of the contoured sheet metal strip are connected to one another by means of the bridge webs. In this way, manufacturing costs can be reduced, since the sheet metal waste when cutting out the contoured sheet metal strips can be significantly reduced.
[0022] It is further advantageous if the rotor sleeve is a fiber composite sleeve comprising a fiber winding, particularly made of glass fiber or carbon fiber, and a cured composite material for embedding the fiber winding. In this way, high preloads can be generated or absorbed with the rotor sleeve, since the fibers are embedded in the cured composite material and thus have a higher load-bearing capacity.
[0023] Advantageously, the magnetic pockets can be U-shaped, V-shaped, or C-shaped, and each can have two, in particular mirror-symmetrical, pocket legs, with each pocket leg being designed to accommodate at least one of the magnets. In this way, the maximum torque that can be generated by the electric machine can be increased.
[0024] The invention further relates to an electrical machine with a rotor according to the invention.
[0025] drawing
[0026] Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description.
[0027] Fig.l shows an inventive
[0028] Rotor of an electrical machine,
[0029] Fig.2 is a sectional view of the rotor according to the invention according to Fig.l,
[0030] Fig.3 is a view from the radial inside of a part of one of the rotor poles of the rotor body according to the invention according to Fig.1 and Fig.2 according to a first embodiment,
[0031] Fig. 4 is a view from the radial inside of a part of one of the rotor poles of the rotor body according to the invention according to Fig. 1 and Fig. 2 according to a second embodiment, Fig. 5 is one of the rotor poles of the rotor according to the invention according to Fig. 1 to Fig. 3 according to the first embodiment,
[0032] Fig.6 two contoured sheet metal strips for
[0033] Production of the rotor according to the invention,
[0034] Fig.7 a bending of a contoured
[0035] Sheet metal strip around a rotor carrier according to Fig.l and Fig.2 for producing the rotor according to the invention,
[0036] Fig.8 shows the rotor according to Fig.2 according to the second embodiment according to Fig.4.
[0037] Description of the embodiments
[0038] Fig.l shows a rotor of an electrical machine according to the invention.
[0039] The rotor 2 according to the invention of an electric machine 1 comprises a rotor carrier 4, in particular a rotor shaft, rotatable about a rotor axis 3, a rotor sleeve 5, and a rotor body 6 arranged between the rotor carrier 4 and the rotor sleeve 5. The rotor body 6 has a plurality of rotor poles 7 and at least one magnetic pocket 8 per rotor pole 7 for receiving magnets 9, in particular permanent magnets. With respect to the rotor axis 3, the rotor body 6 has at least one base body 10 supported on the rotor carrier 4 radially inside the magnetic pockets 8 and outer segment bodies 11 radially outside the magnetic pockets 8.
[0040] The outer segment bodies 11 thus extend in the radial direction from the rotor sleeve 5 to the respective magnet pocket 8. The base bodies 10 extend in the radial direction from the rotor sleeve 5 to the rotor carrier 4.
[0041] The base bodies 10 and / or the outer segment bodies 11 are each formed from a laminated core of laminated core segments 12. The laminated core segments 12 of each laminated core are joined together, for example, by stamping, bonding, or welding.
[0042] The rotor sleeve 5 is, for example, a fiber composite sleeve comprising a fiber winding, in particular made of glass fiber or carbon fiber, and a cured composite material for embedding the fiber winding. The rotor sleeve can be a prefabricated fiber composite sleeve or a fiber composite sleeve wound onto the rotor body 6. For a fiber composite sleeve wound onto the rotor body 6, a fiber winding is first wound, and then the composite material is applied in liquid form.
[0043] The magnetic pockets 8 can, for example, be U-shaped, V-shaped, or C-shaped, and each have two, in particular mirror-symmetrical, pocket legs 8.1. Each of the pocket legs 8.1 is provided for accommodating at least one of the magnets 9.
[0044] Fig.2 shows a sectional view of the rotor according to the invention according to Fig.l.
[0045] According to the invention, a plurality of base bodies 10 are provided, arranged one behind the other in the circumferential direction with respect to the rotor axis 3. Furthermore, according to the invention, a radial separation 14 is formed between adjacent base bodies 10 in the region radially inside the respective magnet pocket 8, which is continuous in the radial direction with respect to the rotor axis 3, to enable radial displacement of the base bodies 10. Furthermore, the base bodies 10 can be clamped between the rotor carrier 4 and the rotor sleeve 5 to clamp the magnets 9 in the magnet pockets 8, for example by means of an oversize of the rotor carrier 4 or by winding the rotor sleeve 5 under tensile stress.
[0046] The radial separation 14 ensures that, viewed in the circumferential direction with respect to the rotor axis 3, each outer segment body 11 has two adjacent base bodies 10 and vice versa.
[0047] The base bodies 10 widen radially inward towards the rotor carrier 4 in the circumferential direction and can, for example, be in the shape of an isosceles trapezoid, T-shaped, mushroom-shaped, umbrella-shaped, wedge-shaped or fir-tree-shaped.
[0048] The outer segment bodies 11 are, for example, circular sector-shaped in cross-section. Furthermore, at least one additional magnet pocket 18 can be provided in each of the outer segment bodies 11 to accommodate one of the magnets 8.
[0049] The radial separation 14 can be located in the region of a pole center 7.1 of the respective rotor pole 7, in particular in the pole center 7.1. The rotor poles 7 are formed in the circumferential direction between two pole edges, wherein a central axis 10.1 of the respective base body 10 forms, for example, one of the two pole edges of one of the rotor poles 7 and, for example, the central axes 10.1 of adjacent base bodies 10 each delimit one of the rotor poles 7 in the circumferential direction.
[0050] According to a first embodiment variant, the rotor carrier 4 can be inserted into the rotor 2 with a pressure generated by the excess in the axial direction in such a way that the base bodies 10 are each displaced in the radial direction while widening the radial separations 14, whereby a prestress in the rotor sleeve 5 and consequently the clamping of the magnets 9 in the magnet pockets 8 can be achieved.
[0051] At least one, in particular each, of the base bodies 10 has, on its inner circumference facing the rotor carrier 4, a shaped contour 20 for transmitting torque, in particular a projection or a recess, which interacts, in particular in a form-fitting manner, with a corresponding counter-shaped contour 21 of the rotor carrier 4. According to Fig. 2, the shaped contour 20 is designed, for example, as a recess, and the counter-shaped contour 21 of the rotor carrier 4 is designed, for example, as a tooth-shaped projection. The shaped contour 20 and the counter-shaped contour 21 are designed, for example, without undercuts, viewed in the radial direction.
[0052] The outer segment bodies 11 and the base bodies 10 can be connected to one another by means of bridge webs 25, which are located on an outer circumference of the rotor body 6 facing the rotor sleeve 5, or can each be provided as separate laminated cores.
[0053] According to a first embodiment, the rotor body 6 can be formed by a package of circular sheet metal laminations, wherein the circular sheet metal laminations each have sheet metal slots 13 for producing the radial separation 14 of the base bodies 10.
[0054] Alternatively, according to a second embodiment, the rotor body 6 can be formed by a so-called flat pack of contoured sheet metal strips 26. The contoured sheet metal strips 26 each comprise first sheet metal segments 27 for forming the outer segment bodies 11 and second sheet metal segments 28 for forming the base bodies 10. The sheet metal segments 27, 28 of the respective contoured sheet metal strip 26 are connected to one another by means of the bridging webs 25, so that the contoured sheet metal strip 26 forms a segment chain. Fig. 6 shows two nested segment chains that can be punched or cut out of a straight sheet metal strip with little sheet metal waste and then stacked with further segment chains to form the flat pack. According to the second embodiment, the flat pack 6 is bent around the rotor carrier 4, with the ends of the flat pack 6 of contoured sheet metal strips 26 lying next to one another in the circumferential direction.The contoured sheet metal strips 25 according to the second embodiment therefore have a length corresponding to the circumference of the rotor body 6.
[0055] According to a third embodiment, the rotor body 6 can also be formed by spiral or helical winding, i.e., so-called edgewise rolling, of a contoured sheet metal strip 26 according to Fig. 6 or Fig. 7 around the rotor carrier 4. As in the second embodiment, the contoured sheet metal strip 26 has first sheet metal segments 27 for forming the outer segment bodies 11 and second sheet metal segments 28 for forming the base bodies 10, wherein the sheet metal segments 27, 28 of the contoured sheet metal strip 26 are also connected to one another by means of the bridge webs 25. Due to the helical winding, the contoured sheet metal strip 25 according to the third embodiment has a length corresponding to a multiple of the circumference of the rotor body 6.
[0056] Fig.3 shows a view from the radial inside of a part of one of the rotor poles of the rotor body according to the invention according to Fig.1 and Fig.2 according to a first embodiment.
[0057] According to the first embodiment, adjacent base bodies 10 each have flat and spaced-apart separating surfaces 15 to form the respective radial separation 14. In this way, a separating slot 16 which is continuous in the axial and radial direction is formed between adjacent base bodies 10 in the region radially inside the respective magnetic pocket 8.
[0058] Fig.4 shows a view from the radial inside of a part of one of the rotor poles of the rotor body according to the invention according to Fig.1 and Fig.2 according to a second embodiment.
[0059] According to the second embodiment, adjacent base bodies 10 each have a separation interface 17 for forming the respective radial separation 14, wherein the respective separation interface 17 is formed by adjacent base bodies 10 engaging with each other by overlapping sheet metal segments 12.
[0060] Fig.5 shows one of the rotor poles of the rotor according to the invention according to Fig.1 to Fig.3 according to the first embodiment.
[0061] In the magnet pockets 8 of the rotor 2, a magnet cooling channel 22 for cooling the magnets 9 can be provided, which is fluidly connected via the respective separating slot 16 to a cooling channel 23 formed in the rotor carrier 4.
[0062] Fig.8 shows the rotor according to Fig.2 according to the second embodiment according to Fig.4.
[0063] The separation interfaces 17 can be formed for a rotor body 6, for example, in that the radial separation 14 with the sheet metal slot 13 is provided alternately off-pole center on the right or off-pole center on the left, viewed in the circumferential direction of the rotor 2 from the rotor pole 7 to the next rotor pole 7.
Claims
Claims 1. Rotor (2) of an electric machine (1), comprising a rotor carrier (4) rotatable about a rotor axis (3), in particular a rotor shaft, a rotor sleeve (5), in particular a composite fiber sleeve, and a rotor body (6) arranged between the rotor carrier (4) and the rotor sleeve (5), which comprises several rotor poles (7) and at least one magnet pocket (8) per rotor pole (7) for receiving magnets (9), in particular permanent magnets, wherein the rotor body (6) has, with respect to the rotor axis (3), at least one base body (10) supported on the rotor carrier (4) radially within the magnet pockets (8) and outer segment bodies (11) radially outside the magnet pockets (8), characterized in that - several base bodies (10) arranged one behind the other in the circumferential direction are provided, - a radially continuous radial separation (14) is formed between adjacent base bodies (10) in the area radially within the respective magnetic pocket (8) to allow a radial displacement of the base bodies (10), - the base bodies (10) for clamping the magnets (9) in the magnet pockets (8) between rotor carrier (4) and rotor sleeve (5) can be clamped, in particular by means of an excess of the rotor carrier (4) or by winding the rotor sleeve (5) under tensile tension.
2. Rotor according to claim 1, characterized in that the rotor carrier (4) is inserted into the rotor (2) with a compression in the axial direction such that the base bodies (10) are each displaced in the radial direction under an expansion of the radial separations (14), whereby a preload in the rotor sleeve (5) and consequently the clamping of the magnets (9) in the magnet pockets (8) can be achieved.
3. Rotor according to one of the preceding claims, characterized in that a. adjacent base bodies (10) each have planar, mutually spaced separating surfaces (15) to form the respective radial separation (14), or b. adjacent base bodies (10) each have a separation interface (17) to form the respective radial separation (14), wherein the respective separation interface (17) is formed by the adjacent base bodies (10) interlocking through overlapping sheet metal segments (12).
4. Rotor according to one of the preceding claims, characterized in that at least one, in particular each, of the base body (10) has on its inner circumference a shaped contour (20) for transmitting torque, in particular a projection or a recess, which interacts with a corresponding counter-shaped contour (21) of the rotor carrier (4), in particular in a form-fitting manner.
5. Rotor according to one of the preceding claims, characterized in that a magnetic cooling channel (22) for cooling the magnets (9) is provided in each of the magnet pockets (8), which is flow-connected via a separation slot (16) formed by the respective radial separation (14) to a cooling channel (23) formed in the rotor carrier (4).
6. Rotor according to one of the preceding claims, characterized in that the outer segment bodies (11) and the base bodies (10) are connected to each other by means of bridge webs (25) located on the outer circumference of the rotor body (6) or are each designed as separate laminated stacks.
7. Rotor according to claim 6, characterized in that the rotor body (6) is formed by a package of circular sheet metal lamellae, wherein the sheet metal lamellae each have sheet metal slots for generating the radial separation (14) of the base bodies (10).
8. Rotor according to claim 6, characterized in that the rotor body (6) is formed by a flat stack of contoured sheet metal strips (26), wherein the contoured sheet metal strips (26) each comprise first sheet metal segments (27) for forming the outer segment bodies (11) and second sheet metal segments (28) for forming the base bodies (10), wherein the sheet metal segments (27, 28) of the respective contoured sheet metal strip (26) are connected to each other by means of the bridge webs (25), wherein the flat stack is bent around the rotor carrier (4). is, wherein the ends of the flat package of contoured sheet metal strips (26) lie next to each other in the circumferential direction.
9. Rotor according to claim 6, characterized in that the rotor body (6) is formed by spirally or helically rolling a contoured sheet metal strip (26) upright around the rotor carrier (4), wherein the contoured sheet metal strip (26) comprises first sheet metal segments (27) for forming the outer segment bodies (11) and second sheet metal segments (28) for forming the base bodies (10), wherein the sheet metal segments (27, 28) of the contoured sheet metal strip (26) are connected to each other by means of the bridge webs (25).
10. Rotor according to one of the preceding claims, characterized in that the rotor sleeve (5) is a fiber composite sleeve comprising a fiber winding, in particular made of glass fiber or carbon fiber, and a cured composite material for embedding the fiber winding.
11. Rotor according to one of the preceding claims, characterized in that the magnet pockets (8) are each U-shaped, V-shaped, C-shaped and each have two pocket legs (8.1) that are in particular mirror-symmetrical, wherein each of the pocket legs (8.1) is designed to receive at least one of the magnets (9).
12. Electric machine with a rotor (2) according to one of the preceding claims.