Rotor of electric machine

Abstract

The invention relates to a rotor (1) of an electric machine, comprising a rotor carrier (3), a rotor body (4) arranged on the rotor carrier (3) and a rotor sleeve (5) surrounding the rotor body (4), the rotor body (4) having an inner passage (6) for guiding the rotor carrier (3) through and a plurality of rotor poles (7), a magnet position (8) of a plurality of magnets (9) being formed in at least one of the rotor poles (7), the respective rotor pole (7) is divided in the radial direction by means of a magnet location (8) into a pole inner section (10) and a pole outer section (11), a magnet pocket (12) is formed in the respective rotor pole (7) between the pole outer section (11) and the pole inner section (10), which magnet pocket is provided for receiving a magnet (9) of the magnet location (8) and has a central region (12.1), which central region is formed in a bridgeless manner, each magnet pocket (12) has two pocket arms (12.2), an axial cooling channel (15) is provided on a pole edge (7.2) of the rotor pole (7), which cooling channel is arranged between the two pocket arms (12.2) of two adjacent magnet pockets (12), the rotor body (4) has a hub section (4.2) in the radial direction within the cooling channel (15), and the rotor sleeve (5) has a preload force, the invention is characterized in that the hub section (4.2) has a plurality of radial interruption slots (16) in the extension thereof in the circumferential direction, each of which opens into one of the cooling channels (15), and that the preload of the rotor sleeve (5) is generated or increased by the radially outwardly acting tensioning of the pole inner section (10) towards the rotor sleeve (5).

Description

Technical Field

[0001] The invention relates to a rotor for an electric machine according to the generic type of the independent claim. Background Art

[0002] WO21225902 A1 discloses a motor rotor, which comprises: a rotor shaft rotatable about a rotor axis; a rotor body, in particular a rotor laminated stack, arranged on the rotor shaft; and a rotor sleeve surrounding the rotor body, wherein the rotor body comprises an inner through-hole for guiding the rotor shaft through and a plurality of rotor poles, each with a pole center, wherein V-shaped magnet positions with two magnets, in particular permanent magnets, are constructed in all rotor poles, wherein the corresponding rotor poles are divided into an inner pole section and an outer pole section by the magnet positions in a radial direction with respect to the rotor axis, wherein magnet pockets are respectively formed in the corresponding rotor poles between the outer pole section and the inner pole section, and the magnet pockets are provided for accommodating the magnet positions. The invention relates to a rotor having a magnet and having a central area, which is particularly located in the area of ​​the pole center and is constructed without bridges, wherein the corresponding magnet pockets each have two pocket arms, which are provided for receiving the magnets and are arranged on opposite sides with respect to the pole center, wherein an axial cooling channel is provided at the pole edge of the rotor pole, which is arranged between the two pocket arms of two adjacent magnet pockets, wherein the rotor body has an annular hub section radially in the cooling channel, which is provided for mechanical coupling with the rotor carrier, wherein the rotor sleeve has a preload for clamping the magnets in the magnet pockets. The rotor sleeve is a wound fiber composite sleeve, which is directly wound onto the rotor body or is joined to the rotor body as a pre-processed rotor sleeve. In the case of a directly wound fiber composite sleeve, the fibers of the fiber composite sleeve are directly wound onto the rotor body under tensile stress during the winding process. A disadvantage of directly wound fiber composite sleeves is that the preload force of the rotor sleeve must be applied solely by the fibers of the fiber composite sleeve, since the composite material of the fiber composite sleeve has not yet hardened during the winding process. Therefore, the preload force that can be generated with a directly wound fiber composite sleeve is limited, so the fiber composite sleeve must be designed to be relatively thick. This leads to a relatively large air gap between the rotor and the stator and to a reduction in the maximum torque.

[0003] The pre-machined rotor sleeve with hardened composite material requires machining of the laminated rotor body at the relatively uneven outer circumference in preparation for joining the rotor sleeve to the rotor body, which increases the machining costs. Summary of the invention

[0004] Advantages of the present invention:

[0005] In contrast, the rotor according to the invention of an electric machine having the characterizing features of the independent claim has the advantage that the preload in the rotor sleeve and thus the tensioning of the magnets in the magnet pockets can be produced more easily and more cost-effectively.

[0006] This is achieved according to the invention in that the hub segment has a plurality of radial interruption slots along its extension in the circumferential direction, each of which opens into one of the cooling channels. In addition, the preload of the rotor sleeve is generated or increased by tensioning the innermost segment against the rotor sleeve in a radially outward direction, in particular by pressing the rotor carrier into the inner through-hole of the rotor body. The interruption slots according to the invention mechanically decouple the innermost segments from one another in the radially inner region and thus enable tensioning of the innermost segment against the rotor sleeve from the radially inner side to the radially outer side.

[0007] According to the present invention, a higher rotor sleeve preload can be generated than in the prior art, because the fibers in the hardened fiber composite can bear a higher load than the fibers in the unhardened fiber composite of the prior art. This makes it possible to implement the rotor sleeve thinner in the radial direction, so that the maximum torque of the electric machine can be increased. In order to generate the preload of the rotor sleeve, the rotor carrier can be pressed into the rotor carrier in a shorter time during processing than in the prior art, when the rotor sleeve is directly wound and hardened on the rotor body. As a result, the processing costs can be significantly reduced.

[0008] Advantageous developments and improvements of the rotor of the electric machine specified in the independent claim are made possible by the measures listed in the dependent claims.

[0009] It is particularly advantageous if the respective cooling channel is designed with regard to the radial position and / or the cross section and / or the cross-sectional shape such that between the cooling channel and the two pocket arms of the adjacent magnet pocket two rotor spokes are formed, the longitudinal extension of the two rotor spokes being respectively greater, in particular several times greater, than their width transversely to the longitudinal extension and being bendable for clamping the magnets. In this way, a high preload can be generated in the rotor sleeve, thereby achieving a high rotational speed stability of the rotor and good clamping of the magnets.

[0010] It is also advantageous if the respective cooling channel has a radially outermost extension which extends in the radial direction up to or beyond the radially innermost edge of the magnets of the respective adjacent magnet pocket. In this way, a rotor spoke with a large longitudinal extension is produced, resulting in a large lever arm for generating the mechanical preload. This flexibly flexible design allows large deformations and thus large mechanical preloads to be generated.

[0011] It is also advantageous that the central region of the magnet pockets each has a pocket bulge, which is bent from the pocket arm of the corresponding magnet pocket and extends radially inwards. In this way, a rotor spoke with a large longitudinal extension is produced, thereby obtaining a large lever arm for generating a mechanical preload.

[0012] It is very advantageous if the circumferential extension of the respective cooling channel widens radially inwards, in particular in that the cross section of the cooling channel is designed triangularly, V-shaped, trapezoidally, or bell-shaped. In this way, a sufficiently flexible rotor spoke is obtained. The rotor spoke can, for example, taper radially inwards.

[0013] It is also advantageous that a press fit is provided between the inner through-hole of the rotor body and the rotor carrier, so that the inner through-hole of the rotor body is expanded when the rotor carrier is assembled, whereby the inner pole segment is tensioned when the rotor spoke is deformed, especially bent, and / or when the inner pole segment is radially displaced in the radial direction toward the magnet and toward the rotor sleeve. In this way, the preload in the rotor sleeve can then be generated by the rotor carrier, for example, by axially pressing the rotor carrier. The rotor sleeve can be implemented thinner by a hardened composite material, so that the maximum torque of the motor can be increased. Compared with the joint connection between the pre-processed fiber composite sleeve and the rotor body in the prior art, the joint connection between the rotor carrier and the rotor body can be established more easily because it includes two steel components as joint partners instead of two different joint partners, especially not fiber composites as joint partners. The high preload in the rotor sleeve ensures that the outer pole segment is tightly abutted at the corresponding inner pole segment, so that there is a very small air gap in the magnet pocket. The maximum torque of the motor can be further increased thereby.

[0014] Advantageously, the rotor body can have a truncated portion at the outer circumference in the region of the pole edge before the rotor carrier is mounted, which truncated portion is brought into contact with the inner circumference of the rotor sleeve by mounting the rotor carrier. In this way, an almost cylindrical outer circumference of the rotor body can be produced in the deformed state, so that a uniform stress distribution is achieved in the rotor sleeve. This can achieve a higher rotor strength and thus a higher maximum rotational speed.

[0015] Furthermore, it is advantageous if the respective cooling duct is arranged with a partial cross section in each rotor pole and with a remaining partial cross section in the respectively adjacent rotor pole. In this way, a sufficiently flexible rotor spoke is obtained.

[0016] According to an advantageous embodiment, the respective outer pole segment can be connected to the inner pole segment of the same rotor pole by means of webs located at the outer circumference of the rotor body or can each be designed as a separate pole body.

[0017] It is also advantageous if the rotor carrier is a rotor shaft, wherein the rotor shaft is a hollow shaft comprising shaft cooling channels, wherein the corresponding cooling channels of the rotor body are flow-connected to the shaft cooling channels via corresponding interruption slots and radial openings of the rotor shaft. In this way, the interruption slots additionally form flow connections for the shaft cooling channels, so that a cooling medium, for example oil, can be conducted through the shaft cooling channels, the radial openings and the interruption slots into the cooling channels of the rotor for cooling the rotor.

[0018] According to an advantageous embodiment, the rotor sleeve comprises a fiber winding, in particular made of glass fibers or carbon fibers, and a hardened composite material for embedding the fiber winding. The fiber composite sleeve can, for example, be pre-machined and assembled in the hardened state without joining forces, in particular without pressing onto the rotor body in the axial direction. In contrast to the prior art, in the case of a pre-machined rotor sleeve, the outer circumference of the rotor body does not have to be machined in preparation for joining the rotor sleeve, since the pressing is only produced by pressing the rotor carrier into the rotor body after the rotor sleeve and the rotor body have been joined without force. Alternatively, the fiber winding of the fiber composite sleeve can be wound directly onto the rotor body with very little preload, the composite material applied to the rotor body hardens, and the preload in the rotor sleeve is subsequently produced by pressing the rotor carrier axially into the rotor sleeve.

[0019] Furthermore, the invention relates to an electric machine having a rotor according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Exemplary embodiments of the invention are shown in simplified form in the drawings and are explained in more detail in the following description.

[0021] Figure 1 A partial view of a rotor according to the invention of an electric machine is shown in section, and

[0022] Figure 2 Shown according to Figure 1 Detailed view of a special embodiment of a rotor body before the rotor carrier is assembled. DETAILED DESCRIPTION

[0023] Figure 1 A partial view of a rotor according to the invention of an electric machine is shown in section.

[0024] The rotor 1 of the electric machine according to the invention comprises a rotor carrier 3, in particular a rotor shaft, which can rotate about a rotor axis 2; a rotor body 4, in particular a rotor laminated core, which is arranged on the rotor carrier 3; and a rotor sleeve 5, in particular a fiber composite sleeve, which surrounds the rotor body 4 at the outer circumference 4.1. The rotor body 4 has an inner passage 6 for guiding the rotor carrier 3 through and a plurality of rotor poles 7, each with a pole center 7.1. In at least one of the rotor poles 7, in particular in all of the rotor poles, a V-shaped, C-shaped or arc-shaped magnet position 8 of a plurality of magnets 9, in particular permanent magnets, is formed. The respective rotor pole 7 is divided by the respective magnet position 8 in the radial direction with respect to the rotor axis 2 into an inner pole section 10 and an outer pole section 11. In the respective rotor pole 7, between the respective outer pole segment 10 and the respective inner pole segment 11, a magnet pocket 12 is formed, which is provided for receiving the magnet 9 of the magnet position 8 and has a central region 12.1, which is located in particular in the region of the pole center 7.1 and is constructed without a bridge. The term "without a bridge" can be understood as meaning that in the central region 12.1, no bridge is implemented, which is used to bridge the magnet pocket 12 or to connect the outer pole segment 10 of the respective rotor pole 7 with the inner pole segment 11. The central region 12.1 is formed, for example, between two magnets 9 facing the pole center 7.1. The magnet 9 can be coated with an insulating portion. As an alternative or in addition, an independent insulating portion can be provided between the magnet 9 and the inner pole segment 10 and / or between the magnet 9 and the outer pole segment 11.

[0025] The respective outer pole segment 11 can be connected to the inner pole segment 10 of the same rotor pole 7 via a bridge 13 located at the outer circumference 4.1 of the rotor body 4. Alternatively, the outer pole segment 11 can be designed as an independent pole body by omitting the bridge 13. The outer pole segment 11 can have a further magnet pocket (not shown) for accommodating at least one further magnet.

[0026] The respective magnet pocket 12 has two pocket arms 12 . 2 , which are provided for receiving a magnet 9 and are arranged on opposite sides with respect to the pole center 7 . 1 , in particular in a mirror-symmetrical manner with respect to the pole center 7 . 1 .

[0027] The rotor poles 7 are each formed between two pole edges 7.2 in the circumferential direction with respect to the rotor axis 2. The pole edges 7.2 are also referred to as q-axes.

[0028] An axial cooling channel 15 is provided at each pole edge 7.2 of the rotor pole 7, which is arranged between two pocket arms 12.2 of two adjacent magnet pockets 12 and extends at least partially through the rotor body 4 in the axial direction with respect to the rotor axis 2. The respective cooling channel 15 is arranged in each case with a partial cross section in the rotor pole 7 and with the remaining partial cross section in the respective adjacent rotor pole 7.

[0029] The rotor body 4 has a hub section 4 . 2 radially within the cooling channel 15 , which is designed for mechanical coupling to the rotor carrier 3 , ie for transmitting torque.

[0030] The rotor sleeve 5 has a mechanical preload, in particular for clamping the magnets 9 in the magnet pockets 12 or in order to have as few or as few air gaps as possible in the magnet pockets 12 in the direction of the magnetic flux.

[0031] According to the invention, the hub segment 4.2 has a plurality of radial interruption slots 16 along its extension in the circumferential direction, which extend in the radial direction from the inner circumference of the hub segment 4.2 facing the rotor carrier 3 and each open into or lead into one of the cooling channels 15. According to the invention, the prestressing of the rotor sleeve 5 is generated or increased by tensioning the inner pole segment 10 in the radial direction toward the rotor sleeve 5, in particular by pressing the rotor carrier 3 into the inner passage 6 of the rotor body 4. The hub segment 4.2 of the rotor body 4 is divided or separated into annular segments 17 by the interruption slots 16. The interruption slots 16 are, for example, each located on or near one of the pole edges 7.2 of the rotor pole 7.

[0032] The respective cooling channel 15 is designed with respect to the radial position and / or the cross section and / or the cross-sectional shape in such a way that two rotor spokes 18 are formed between the cooling channel 15 and the two bag arms 12.2 of the adjacent magnet pocket 12, the longitudinal extension L of which is respectively greater, in particular multiple greater, than its width B transversely to the longitudinal extension L and which can be bent for clamping the magnets 9. The cross-sectional side of the respective cooling channel 15 facing the respective rotor spoke 18 forms, for example, the length of the respective rotor spoke 18.

[0033] The respective cooling channel 15 can have a radially outermost extension which extends in the radial direction up to or beyond the radially innermost edge of the magnet 9 of the respective adjacent magnet pocket 12. In addition, the central region 12.1 of the magnet pocket 12 can each have a pocket bulge 12.3 which is bent from the pocket arm 12.2 of the respective magnet pocket 12 and extends radially inwardly.

[0034] The extension of the respective cooling channel 15 in the circumferential direction can widen radially inwards, for example by virtue of the cross section of the cooling channel 15 being of triangular, V-shaped, trapezoidal or bell-shaped design and oriented accordingly.

[0035] A press fit is provided between the inner passage 6 of the rotor body 4 and the rotor carrier 3, so that the inner passage 6 of the rotor body 4 is expanded when the rotor carrier 3 is mounted, whereby the inner pole segment 10 is tensioned when the rotor spokes 18 are deformed, in particular bent, and / or when the inner pole segment 10 is radially displaced in the radial direction toward the magnets 9 and toward the rotor sleeve 5. The rotor carrier 3 is pressed into the inner passage 6 of the rotor body 4, for example, in the axial direction. In addition to the press connection between the rotor body 4 and the rotor carrier 3, a form-locking joint connection can also be provided.

[0036] The rotor sleeve 5 is, for example, a fiber composite sleeve which comprises a fiber winding, in particular made of glass fibers or carbon fibers, and a hardened composite material for embedding the fiber winding.

[0037] The rotor shaft 3 can be a hollow shaft comprising a shaft cooling channel 20 , wherein the corresponding cooling channel 15 of the rotor body 4 is in flow connection with the shaft cooling channel 20 via corresponding interruption slots 16 and radial openings 21 in the rotor shaft 3

[0038] Optionally, after the rotor carrier 3 has been pressed in and the rotor sleeve 5 has been preloaded, a filler material can also be additionally injected into the magnet pockets 12 .

[0039] Figure 2 Shown according to Figure 1 Detailed view of a special embodiment of a rotor body before the rotor carrier is assembled.

[0040] Before the rotor carrier 3 is mounted, the rotor body 4 can have, at the outer circumference 4 . 1 in the region of the pole edge 7 . 3 , respectively, a flattened portion 22 which, by mounting the rotor carrier 3 , comes into contact with the inner circumference of the rotor sleeve 5 by deformation of the webs 13 and radial displacement of the respective inner pole segment 10 .

Claims

1. A rotor (1) of an electric motor, the rotor comprising: A rotor carrier (3), in particular a rotor shaft, rotatable about a rotor axis (2); a rotor body (4), in particular a rotor lamination stack, arranged on the rotor carrier (3); and a rotor sleeve (5), in particular a fiber composite sleeve, surrounding the rotor body (4), in, The rotor body (4) has an inner through-hole (6) for guiding the rotor carrier (3) through, and a plurality of rotor poles (7), each of which has a pole center (7.1), wherein a plurality of magnets (9), in particular permanent magnets, are configured in at least one of the rotor poles (7), in particular all of the rotor poles, wherein the respective rotor pole (7) is divided into an inner pole section (10) and an outer pole section (11) by the magnet section (8) in a radial direction with respect to the rotor axis (2), wherein a magnet pocket (12) is formed in each case between the outer pole section (11) and the inner pole section (10) in the respective rotor pole (7), the magnet pocket being configured to receive the magnets (9) of the magnet section (8) and having a central region (12.1) having a central region (12.2) and a central region (12.3) having a central region (12.4) and a central region (12.5) having a central region (12.6) and a central region (12.7) having a central region (12.8) and a central region (12.9) having a central region (12.1) and a central region (12.1) having a central region (12.1) and a central region (12.1) thereof. The region is particularly located in the region of the pole center (7.1) and is constructed in a bridge-free manner, wherein the corresponding magnet pockets (12) each have two pocket arms (12.2), which are arranged on opposite sides with respect to the pole center (7.1), wherein an axial cooling channel (15) is respectively provided at the pole edge (7.2) of the rotor pole (7), and the axial cooling channel is arranged between the two pocket arms (12.2) of two adjacent magnet pockets (12), wherein the rotor body (4) has a hub section (4.2) radially in the cooling channel (15), which hub section is provided for mechanical coupling with the rotor carrier (3), wherein the rotor sleeve (5) has a preload, in particular for clamping the magnet (9) into the magnet pocket (12), characterized in that - the hub section (4.2) has, along its extension in the circumferential direction, a plurality of radial interruption slots (16), each of which opens into one of the cooling channels (15), The preload of the rotor sleeve (5) is generated or increased by tensioning the inner pole segment (10) in the radially outward direction toward the rotor sleeve (5), in particular by pressing the rotor carrier (3) into an inner passage (6) of the rotor body (4).

2. The rotor according to claim 1, characterized in that The corresponding cooling channel (15) is implemented in such a way with respect to the radial position and / or the cross-section and / or the cross-sectional shape that two rotor spokes (18) are formed between the cooling channel (15) and the two bag arms (12.2) of the adjacent magnet bag (12), the longitudinal extension (L) of the two rotor spokes being respectively greater, in particular several times greater, than their width (B) transverse to the longitudinal extension (L), and the two rotor spokes being bendable for clamping the magnet (9).

3. A rotor according to any one of the preceding claims, characterised in that The respective cooling channel (15) has a radially outermost extension which extends in the radial direction to or beyond the radially innermost edge of the magnet (9) of the respective adjacent magnet pocket (12).

4. A rotor according to any one of the preceding claims, characterised in that The central area (12.1) of the magnet pocket (12) has a pocket bulge (12.3) which is bent from a pocket arm (12.2) of the magnet pocket (12) and extends radially inward.

5. A rotor according to any one of the preceding claims, characterised in that The extension of the respective cooling channel (15) in the circumferential direction widens radially inwards, in particular in that the cross section of the cooling channel (15) is designed to be triangular, V-shaped, trapezoidal or bell-shaped.

6. A rotor according to any one of the preceding claims, characterised in that A press fit is provided between the inner through-hole (6) of the rotor body (4) and the rotor carrier (3), so that the inner through-hole (6) of the rotor body (4) is expanded when the rotor carrier (3) is assembled, thereby tensioning the inner pole segment (10) when the rotor spokes (18) are deformed, in particular bent, and / or when the inner pole segment (10) is radially displaced in a radial direction toward the magnet (9) and toward the rotor sleeve (5).

7. A rotor according to any one of the preceding claims, characterised in that The rotor body (4) has a flattened portion (22) at the outer circumference (4.1) in the region of the pole edge (7.2) before the rotor carrier (3) is mounted, which flattened portion comes into contact with the inner circumference of the rotor sleeve (5) when the rotor carrier (3) is mounted.

8. A rotor according to any one of the preceding claims, characterised in that The respective cooling duct (15) is arranged in each case with a partial cross section in a rotor pole (7) and with a remaining partial cross section in a respectively adjacent rotor pole (7).

9. A rotor according to any one of the preceding claims, characterised in that The corresponding outer pole segment (11) is connected to the inner pole segment (10) of the same rotor pole (7) by means of a bridge (13) located at the outer circumference (4.1) of the rotor body (4) or is respectively implemented as an independent pole body.

10. A rotor according to any one of the preceding claims, characterised in that The rotor carrier (3) is a rotor shaft, wherein the rotor shaft (3) is a hollow shaft comprising a shaft cooling channel (20), wherein corresponding cooling channels (15) of the rotor body (4) are fluidically connected to the shaft cooling channel (20) via corresponding interruption gaps (16) and radial openings (21) of the rotor shaft (3).

11. A rotor according to any one of the preceding claims, characterised in that The rotor sleeve (5) comprises a fiber winding, in particular composed of glass fibers or carbon fibers, and a hardened composite material for embedding the fiber winding.

12. An electric machine having a rotor (1) according to any one of the preceding claims.

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