Rotor of an electric machine

Abstract

A rotor (1) of an electric machine comprising a rotor carrier (3), a rotor body (4) disposed on the rotor carrier (3), and a rotor sleeve (5) surrounding the rotor body (4), wherein the rotor body (4) has an internal passage (6) for passing through the rotor carrier (3) and a plurality of rotor poles (7), at least one of the rotor poles (7) has a magnet position (8) for a plurality of magnets (9), each rotor pole (7) is divided into an inner pole segment (10) and an outer pole segment (11) in the radial direction by the magnet position (8), in each rotor pole (7), a magnet pocket (12) is formed between the outer pole segment (11) and the inner pole segment (10), the magnet pocket (12) is provided for accommodating the magnet (9) at the magnet position (8), has a central region (12.1), the central region (12.1) is configured without a bridge web, each magnet pocket (12) has two pocket legs (12.2), axial cooling channels (15) are provided at the pole edge portions (7.2) of the rotor poles (7), the axial cooling channels (15) are disposed between the two pocket legs (12.2) of two adjacent magnet pockets (12), the rotor body (4) has a hub section (4.2) radially inside the cooling channels (15), the rotor sleeve (5) has a prestress, in the rotor (1), the hub section (4.2) has a plurality of radial blocking slots (16) along its circumferential extension, the blocking slots (16) each open into one of the cooling channels (15), and the prestress of the rotor sleeve (5) is generated or increased by the tension of the inner pole segment (10) against the rotor sleeve (5) acting radially outward.

Description

Technical Field

[0001] The present invention is based on a rotor of an electric machine as set forth in the preamble of the independent claim.

Background Art

[0002] From International Publication No. WO 2021 / 225902 A1, there is known an electric machine rotor comprising a rotor shaft rotatable about a rotor axis, a rotor body arranged on the rotor shaft, in particular a rotor laminated core, and a rotor sleeve surrounding the rotor body, wherein the rotor body has an internal passage for passing the rotor shaft and a plurality of rotor poles each having a pole center, and for all the rotor poles, two magnets, in particular V-shaped magnet positions for permanent magnets, are configured, and each rotor pole is divided, depending on the magnet position, into an inner pole segment and an outer pole segment radially with respect to the rotor axis, and in each rotor pole, a magnet pocket is formed between the outer pole segment and the inner pole segment, the magnet pocket being provided for accommodating the magnet at the magnet position, having a central region, the central region being located in particular in the region of the pole center and being configured without a bridge web, each magnet pocket having two pocket legs each, the pocket legs being provided for accommodating the magnet and being arranged on sides facing each other with respect to the pole center, and axial cooling channels are provided at the pole edges of the rotor poles, the axial cooling channels being arranged between two pocket legs of two adjacent magnet pockets, the rotor body having a ring-shaped hub section radially inside the cooling channels, the hub section being provided for mechanical coupling with a rotor carrier, and the rotor sleeve having a prestress for clamping the magnets in the magnet pockets. The rotor sleeve is a wound fiber composite sleeve which is wound directly onto the rotor body or joined to the rotor body as a prefabricated rotor sleeve. In the case of a directly wound fiber composite sleeve, the fibers of the fiber composite sleeve are wound directly onto the rotor body in a winding process under tensile stress. The disadvantage of a directly wound fiber composite sleeve is that since the composite material of the fiber composite sleeve has not yet been cured during the winding process, the prestress of the rotor sleeve has to be applied only by the fibers of the fiber composite sleeve. Therefore, the prestress that can be generated with a directly wound fiber composite sleeve is limited, and the fiber composite sleeve has to be designed relatively thick. This results in a relatively large gap between the rotor and the stator and a reduction in the maximum torque.

[0003] A prefabricated rotor sleeve having a cured composite material requires machining of the laminated rotor body with a relatively uneven outer circumference as preparation for joining the rotor sleeve to the rotor body, which increases the manufacturing cost. SUMMARY OF THE INVENTION

[0004] Thus, the electric machine rotor according to the invention with the features in the characterizing part of the independent claims has the advantage that the pre-tension in the rotor sleeve, and thus the tension of the magnets in the magnet pockets, can be generated more easily and at lower cost.

[0005] According to the invention, this is achieved in that the hub section has a plurality of radial cut-off slots along its extension in the circumferential direction, and the cut-off slots each open into one of the cooling channels. Furthermore, the pre-tension of the rotor sleeve is generated or increased by the tension of the inner pole segments against the rotor sleeve acting radially outwards, in particular by press-fitting the rotor carrier into the internal passage of the rotor body. The cut-off slots according to the invention mechanically separate the inner pole segments from each other in the radially inner region, thereby enabling the tension of the inner pole segments against the rotor sleeve acting from the radially inner side to the radially outer side.

[0006] According to the invention, the fibers of the cured fiber composite material can have higher resistance than the fibers of the uncured fiber composite material of the prior art, so that the pre-tension of the rotor sleeve can be made higher than in the prior art. This enables the rotor sleeve to be designed thinner in the radial direction, and thus the maximum torque of the electric machine can be increased. Press-fitting the rotor carrier into the rotor carrier to generate the pre-tension of the rotor sleeve can be done in a shorter time during manufacturing than the winding and curing of the rotor sleeve directly onto the rotor body in the prior art. Thus, the manufacturing cost can be significantly reduced.

[0007] By means of the means described in the dependent claims, advantageous developments and improvements of the rotor of the electric machine described in the independent claims are possible. Each cooling channel is designed such that, with respect to the radial position and / or the cross-section and / or the cross-sectional shape, two rotor spokes are formed between the two pocket legs of the magnet pocket adjacent to the cooling channel, and the longitudinal extension of the rotor spoke is greater, in particular several times greater, than the width of the rotor spoke across the longitudinal extension, and it is particularly advantageous that it can flex to clamp the magnet. In this way, a high pre-tension can be generated in the rotor sleeve, thereby enabling high rotational speed stability of the rotor and good clamping of the magnet.

[0008] It is further advantageous if each cooling channel has a radially outermost extension that reaches or extends beyond the radially innermost end of the magnet of the adjacent magnet pocket in the radial direction. In this way, rotor spokes with large longitudinal extensions are created, and thus a large lever arm for generating mechanical pre-tension is realized. This flexible structure allows for large deformations and thus large mechanical pre-tensions to be generated.

[0009] It is further advantageous if the central region of each magnet pocket has a pocket bulge, and the pocket bulge bends from the pocket leg of each magnet pocket and extends radially inward. In this way, rotor spokes with large longitudinal extensions are created, and thus a large lever arm for generating mechanical pre-tension is realized.

[0010] In particular, by configuring the cross-section of the cooling channel to be triangular, V-shaped, trapezoidal, or bell-shaped, it is highly advantageous that the circumferential extension of each cooling channel widens towards the radially inner side. In this way, a sufficiently flexible rotor spoke is realized. For example, the rotor spoke can be made thinner towards the radially inner side.

[0011] Also, a press fit is provided between the internal passage of the rotor body and the rotor carrier, and the internal passage of the rotor body is widened during the assembly of the rotor carrier, so that the inner pole segment is radially tensioned against the magnet and the rotor sleeve under deformation of the rotor spoke, especially bending, and / or under radial displacement of the inner pole segment. This way, the pre-tension in the rotor sleeve can be generated later by the rotor carrier, for example by axially pressing the rotor carrier. The hardened composite material allows the rotor sleeve to be designed thinner, thus increasing the maximum torque of the electromechanical machine. The joint connection between the rotor carrier and the rotor body includes two steel parts as mating partners and does not include two different mating partners, especially does not include a fiber composite material as a mating partner, so it can be manufactured more easily than the joint connection between a prefabricated fiber composite sleeve and the rotor body in the prior art. The high pre-tension in the rotor sleeve results in the outer pole segment being in close contact with each inner pole segment, and the voids present in the magnet pocket becoming very small. This can further increase the maximum torque of the electromechanical machine.

[0012] Advantageously, the rotor body may each have a flat portion on the outer periphery within the region of the pole insulation before the assembly of the rotor carrier, and the flat portion abuts against the inner periphery of the rotor sleeve respectively by the assembly of the rotor carrier. This way, a substantially cylindrical outer periphery of the rotor body in the formed state can be created, and thus a uniform stress distribution in the rotor sleeve is achieved. This enables an improvement in the strength of the rotor and thus an increase in the maximum rotational speed.

[0013] It is further advantageous if each cooling channel is arranged within one rotor pole in a partial cross-section and within the adjacent rotor poles in the remaining partial cross-sections respectively. This way, a sufficiently flexible rotor spoke is realized.

[0014] According to an advantageous form, each outer pole segment may be connected to the inner pole segment of the same rotor pole by a bridge web located on the outer circumference of the rotor body, or may be designed as a separate pole body.

[0015] It is further advantageous if the rotor carrier is a rotor shaft, the rotor shaft is a hollow shaft including a shaft cooling channel, and each cooling channel of the rotor body is in fluid communication with the shaft cooling channel via each blocking slot and radial opening of the rotor shaft. In this way, the blocking slots further form fluid communication to the shaft cooling channel, so that a cooling medium, such as oil, can be guided through the shaft cooling channel, the radial openings, and the blocking slots to the cooling channels of the rotor for cooling the rotor.

[0016] According to an advantageous form, the rotor sleeve includes in particular a fiber winding made of glass fiber or carbon fiber and a cured composite material for embedding the fiber winding. The fiber composite sleeve can be, for example, prefabricated and in a cured state, and can be installed without bonding force, in particular without axial pressing against the rotor body. In the case of a prefabricated rotor sleeve, unlike the prior art, the outer circumference of the rotor body does not need to be mechanically processed as a preparation for joining the rotor sleeve. This is because pressure is generated by press-fitting the rotor carrier onto the rotor body after joining the rotor sleeve and the rotor body without applying force. Alternatively, the fiber winding of the fiber composite sleeve can be directly wound around the rotor body with a very low pre-tension, the attached composite material can be cured on the rotor body, and later, the pre-tension of the rotor sleeve can be generated by axially press-fitting the rotor carrier.

[0017] The invention further relates to an electromechanical machine comprising a rotor according to the invention. Exemplary embodiments of the invention are shown schematically in the drawings and will be described in more detail in the following description.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

DETAILED DESCRIPTION OF THE INVENTION

[0019] FIG. 1 shows a partial cross-sectional view of the rotor of an electric machine according to the present invention. The rotor 1 of the electric machine according to the present invention includes a rotor carrier 3 rotatable about a rotor shaft 2, particularly a rotor shaft, a rotor body 4 disposed on the rotor carrier 3, particularly a rotor laminated core, and a rotor sleeve 5 surrounding the rotor body 4 at an outer periphery 4.1, particularly a fiber composite sleeve. The rotor body 4 has an internal passage 6 for passing through the rotor carrier 3 and a plurality of rotor poles 7 each having a pole center 7.1. A plurality of magnet positions 8, particularly V-shaped, C-shaped, or arc-shaped magnet positions for permanent magnets, are formed in at least one, particularly all, of the rotor poles 7. Each rotor pole 7 is divided by each magnet position 8 into an inner pole segment 10 and an outer pole segment 11 in a radial direction with respect to the rotor shaft 2. In each rotor pole 7, a magnet pocket 12 is formed between each outer pole segment 10 and each inner pole segment 11, and the magnet pocket 12 is provided for accommodating the magnet 9 at the magnet position 8 and has a central region 12.1, and the central region 12.1 is particularly located in the region of the pole center 7.1 and is configured without a bridge web. The term "without a bridge web" means that no bridge web is designed in the central region 12.1 to bridge the magnet pocket 12 or to connect the outer pole segment 10 and the inner pole segment 11 of each rotor pole 7. 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 insulator. Alternatively or additionally, separate insulators 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, respectively.

[0020] Each outer pole segment 11 may be connected to the inner pole segment 10 of the same rotor pole 7 by a bridge web 13 located on the outer periphery 4.1 of the rotor body 4. Alternatively, by omitting the bridge web 13, the outer pole segment 11 may be designed as a separate pole body. The outer pole segment 11 may have at least one additional magnet pocket (not shown) for accommodating at least one additional magnet.

[0021] Each magnet pocket 12 has two pocket legs 12.2, respectively, and the pocket legs 12.2 are provided for accommodating the magnet 9 and are arranged on the sides facing each other with respect to the pole center 7.1, particularly symmetrically with respect to the pole center 7.1 in a mirror image manner.

[0022] The rotor poles 7 are formed circumferentially with respect to the rotor axis 2 between two pole edges 7.2, respectively. The pole edges 7.2 are also called the q-axis. Axial cooling channels 15 are provided in the pole edges 7.2 of the rotor poles 7, respectively. The axial cooling channels 15 are arranged between the two pocket legs 12.2 of two adjacent magnet pockets 12 and extend axially with respect to the rotor axis 2 through at least part of the rotor body 4. Each cooling channel 15 is arranged within one rotor pole 7 in one partial cross-section and within the adjacent rotor poles 7 in the remaining partial cross-sections, respectively.

[0023] The rotor body 4 has a hub section 4.2 radially inside the cooling channels 15, and the hub section 4.2 is configured for mechanical coupling with the rotor carrier 3, i.e., for torque transmission.

[0024] The rotor sleeve 5 has a mechanical pre-tension, particularly for clamping the magnet 9 within the magnet pocket 12, or for minimizing or making as small as possible the air gap within the magnet pocket 12 in the direction of the magnetic flux.

[0025] According to the present invention, the hub section 4.2 has a plurality of radial blocking slots 16 along its circumferential extension, and the blocking slots 16 are intended to extend radially from the inner circumference of the hub section 4.2 facing the rotor carrier 3 and open or communicate with one of the cooling channels 15 respectively. Further, according to the present invention, the pre-tension of the rotor sleeve 5 is intended to be generated or increased by the tension of the inner pole segment 10 on the rotor sleeve 5 acting radially outward, in particular by press-fitting the rotor carrier 3 into the internal passage 6 of the rotor body 4. The hub section 4.2 of the rotor body 4 is divided or separated into a ring section 17 by the blocking slots 16. The blocking slots 16 are located, for example, at or near one of the pole edges 7.2 of each rotor pole 7 respectively.

[0026] Each cooling channel 15 is designed such that two rotor spokes 18 are formed between the cooling channel 15 and two pocket legs 12.2 of the adjacent magnet pocket 12 with respect to the radial position and / or cross-section and / or cross-sectional shape, and the longitudinal extension L of the rotor spoke 18 is greater than the width B of the rotor spoke 18 across the longitudinal extension L, particularly several times larger, and can be bent to clamp the magnet 9. For example, the sides of the cross-section of each cooling channel 15 facing each rotor spoke 18 form the length of each rotor spoke 18.

[0027] Each cooling channel 15 may have a radially outermost extension that reaches or extends beyond the radially innermost end of the magnet 9 in the adjacent magnet pocket 12 in the radial direction. Further, the central region 12.1 of the magnetic pocket 12 may have a pocket bulge 12.3 respectively, and the pocket bulge 12.3 bends from the pocket leg 12.2 of each magnetic pocket 12 and extends radially inward.

[0028] For example, by configuring the cross-section of the cooling channel 15 to be triangular, V-shaped, trapezoidal, or bell-shaped and aligning it accordingly, the circumferential extension of each cooling channel 15 can be widened radially inward.

[0029] A press fit is provided between the internal passage 6 of the rotor body 4 and the rotor carrier 3. When the rotor carrier 3 is assembled, the internal passage 6 of the rotor body 4 is expanded, so that the inner pole segment 10 is radially tensioned against the magnet 9 and the rotor sleeve 5 under the deformation of the rotor spoke 18, particularly bending, and / or under the radial displacement of the inner pole segment 10. For example, the rotor carrier 3 is press-fitted axially into the internal passage 6 of the rotor body 4. In addition to the press-fit connection between the rotor body 4 and the rotor carrier 3, a fitting joint can also be provided.

[0030] The rotor sleeve 5 is, for example, a fiber composite sleeve including a fiber winding made particularly of glass fiber or carbon fiber and a cured composite material for embedding the fiber winding. The rotor shaft 3 may be a hollow shaft including a shaft cooling channel 20. Each cooling channel 15 of the rotor body 4 is in fluid communication with the shaft cooling channel 20 through each blocking slot 16 and the radial opening 21 of the rotor shaft 3.

[0031] After the press fit of the rotor carrier 3 and the pre-tensioning of the rotor sleeve 5, optionally, a casting compound can be further filled into the magnet pocket 12. FIG. 2 shows a detailed view of a special design of the rotor body according to FIG. 1 before the assembly of the rotor carrier.

[0032] Before the assembly of the rotor carrier 3, the rotor body 4 may each have a flat portion 22 on the outer periphery 4.1 in the region of the pole insulation 7.3. This flat portion 22 abuts against the inner periphery of the rotor sleeve 5 by the assembly of the rotor carrier 3 under the deformation of the bridge web 13 and the radial displacement of each inner pole segment 10.

Claims

1. An electric machine rotor (1) comprising a rotor carrier (3) rotatable about a rotor shaft (2), in particular a rotor shaft, a rotor body (4) arranged on the rotor carrier (3), in particular a rotor laminated core, and a rotor sleeve (5) surrounding the rotor body (4), in particular a fiber composite sleeve, wherein the rotor body (4) has an internal passage (6) for passing through the rotor carrier (3) and a plurality of rotor poles (7) each having a pole center (7.1), and at least one, in particular all, of the rotor poles (7) are configured with a plurality of magnet positions (8) for magnets (9), in particular V-shaped, C-shaped, or arcuate magnet positions for permanent magnets, and each of the rotor poles (7) is divided by the magnet position (8) into an inner pole segment (10) and an outer pole segment (11) radially inward with respect to the rotor shaft (2), and in each of the rotor poles (7), a magnet pocket (12) is formed between the outer pole segment (11) and the inner pole segment (10), the magnet pocket (12) being provided for accommodating the magnet (9) at the magnet position (8), having a central region (12.1), the central region (12.1) being located particularly in the region of the pole center (7.1) and being configured without a bridge web, each of the magnet pockets (12) having two pocket legs (12.2), the pocket legs (12.2) being arranged on opposite sides with respect to the pole center (7.1), and axial cooling channels (15) are provided at the pole edges (7.2) of the rotor poles (7), the axial cooling channels (15) being arranged between two pocket legs (12.2) of two adjacent magnet pockets (12), the rotor body (4) having a hub section (4.2) radially inside the cooling channels (15), the hub section (4.2) being provided for mechanical coupling with the rotor carrier (3), and the rotor sleeve (5) having a prestress, in particular for clamping the magnet (9) in the magnet pocket (12), in the rotor (1), the hub section (4.2) has a plurality of radial blocking slots (16) along its circumferential extension, and the blocking slots (16) each open into one of the cooling channels (15), The pre-tension of the rotor sleeve (5) is generated or increased by the tension of the inner pole segment (10) on the rotor sleeve (5) acting radially outwards, in particular by press-fitting the rotor carrier (3) into the internal passage (6) of the rotor body (4). Rotor (1), characterized in that. [

2. ] [

1. ] The rotor according to claim 1, characterized in that each of the cooling channels (15) is designed such that two rotor spokes (18) are formed between the cooling channel (15) and the two pocket legs (12.2) of the adjacent magnet pocket (12) with respect to the radial position, and / or the cross-section and / or the cross-sectional shape, and the longitudinal extension (L) of the rotor spoke (18) is greater than, in particular several times greater than, the width (B) of the rotor spoke (18) across the longitudinal extension (L), and can be deflected to clamp the magnet (9). [

3. ] [[Claim 1 or 2]] The rotor according to claim 1 or 2, characterized in that each of the cooling channels (15) has a radially outermost extension that reaches or extends beyond the radially innermost end of the magnet (9) of the adjacent magnet pocket (12) in the radial direction. [

4. ] [[Claim 1 to 3]] The rotor according to any one of claims 1 to 3, characterized in that the central region (12.1) of each of the magnet pockets (12) has a pocket bulge (12.3), and the pocket bulge (12.3) bends from the pocket leg (12.2) of the magnet pocket (12) and extends radially inwards. [

5. ] [[Claim 1 to 4]] The rotor according to any one of claims 1 to 4, characterized in that, in particular, the cross-section of the cooling channel (15) is configured in a triangular, V-shaped, trapezoidal or bell-shaped manner, such that the extension of each of the cooling channels (15) in the circumferential direction widens towards the radially inner side. [

6. ] A press fit is provided between the internal passage (6) of the rotor body (4) and the rotor carrier (3), and the internal passage (6) of the rotor body (4) is expanded during the assembly of the rotor carrier (3), so that, under deformation, in particular bending, of the rotor spokes (18) and / or under radial displacement of the inner pole segments (10), the inner pole segments (10) are radially tensioned against the magnets (9) and the rotor sleeve (5). The rotor according to any one of claims 1 to 5, characterized in that.

7. Before the assembly of the rotor carrier (3), the rotor body (4) has flat portions (22) on the outer periphery (4.1) within the region of the pole edges (7.2), and the flat portions (22) abut against the inner periphery of the rotor sleeve (5) by the assembly of the rotor carrier (3). The rotor according to any one of claims 1 to 6, characterized in that.

8. Each of the cooling channels (15) is arranged within one rotor pole (7) in a partial cross-section and within adjacent rotor poles (7) in the remaining partial cross-sections. The rotor according to any one of claims 1 to 7, characterized in that.

9. Each of the outer pole segments (11) is connected to the inner pole segment (10) of the same rotor pole (7) by a bridge web (13) located on the outer periphery (4.1) of the rotor body (4), or is designed as a separate pole body. The rotor according to any one of claims 1 to 8, characterized in that.

10. The rotor carrier (3) is a rotor shaft, the rotor shaft (3) is a hollow shaft including a shaft cooling channel (20), and each of the cooling channels (15) of the rotor body (4) is in fluid communication with the shaft cooling channel (20) through each of the blocking slots (16) and radial openings (21) of the rotor shaft (3). The rotor according to any one of claims 1 to 9, characterized in that.

11. The rotor sleeve (5) includes, in particular, a fiber winding made of glass fiber or carbon fiber and a cured composite material for embedding the fiber winding. The rotor according to any one of claims 1 to 10, characterized in that.

12. An electromechanical machine comprising a rotor (1) according to any one of claims 1 to 11.

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