Rotor of an electric machine

Abstract

Disclosed is a rotor (1) of an electric machine, having a rotor carrier (3), having a rotor body (4) arranged on the rotor carrier (3), and having a rotor sleeve (5) surrounding the rotor body (4), the rotor body (4) comprising an inner passage (6) for the leadthrough of the rotor carrier (3) and comprising multiple rotor poles (7), a magnet layer (8) composed of multiple magnets (9) being arranged in at least one of the rotor poles (7), each rotor pole (7) being divided in the radial direction into a pole inner segment (10) and a pole outer segment (11) by the magnet layer (8), a magnet pocket (12) being formed in each case between the pole outer segment (11) and the pole inner segment (10) in each rotor pole (7), said magnet pocket being provided for receiving the magnets (9) of the magnet layer (8) and comprising a central region (12.1) that is formed without a bridging strut, each magnet pocket (12) having two pocket legs (12.2), an axial cooling channel (15) being provided in each case at pole margins (7.2) of the rotor poles (7) and being arranged between two pocket legs (12.2) of two adjacent magnet pockets (12), the rotor body (4) having a hub portion (4.2) radially within the cooling channels (15), the rotor sleeve (5) being preloaded, characterized in that the hub portion (4.2) has, along its extent in the circumferential direction, multiple radial interruption slots (16) which each open into one of the cooling channels (15), and in that the preload of the rotor sleeve (5) is generated or increased by virtue of the pole inner segments (10) being radially outwardly braced against the rotor sleeve (5).

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 WO21225902 A1, comprising a rotor shaft rotatable about a rotor axis, a rotor body, in particular a rotor core, arranged on the rotor shaft, and a rotor sleeve enclosing the rotor body, wherein the rotor body has an inner passage for the passage of the rotor shaft and a plurality of rotor poles, each with a pole center, wherein a V-shaped magnetic layer of two magnets, in particular permanent magnets, is formed in all rotor poles, wherein the respective rotor pole is divided by the magnetic layer in the radial direction with respect to the rotor axis into an inner pole segment and an outer pole segment, wherein in the respective rotor pole, between the outer pole segment and the inner pole segment, a magnetic pocket is formed, which is provided for receiving the magnets of the magnetic layer and has a central region, which is located in particular in the region of the pole center and is designed without a bridge web,wherein each magnet pocket has two pocket legs, 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 edges of the rotor poles, which is arranged between two pocket legs of two adjacent magnet pockets, wherein the rotor body has an annular hub section radially within the cooling channels, which is provided for mechanical coupling to 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 either 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 the directly wound fiber composite sleeve is that the preload 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 cured during the winding process. The preload that can be generated with the directly wound fiber composite sleeve is therefore limited, so the fiber composite sleeve must be comparatively thick. This leads to a comparatively large air gap between the rotor and stator and to a reduction in the maximum torque.

[0007] The prefabricated rotor sleeve with cured composite material requires mechanical machining of the laminated rotor body on the comparatively uneven outer circumference in preparation for joining the rotor sleeve to the rotor body, which increases the manufacturing costs.

[0008] Advantages of the invention

[0009] The rotor of an electrical machine according to the invention with the characterizing features of the main claim has the advantage that the prestress in the rotor sleeve and consequently the bracing of the magnets in the magnet pockets can be produced more easily and cost-effectively.

[0010] This is achieved according to the invention in that the hub section has a plurality of radial interrupter slots along its circumferential extension, each of which opens into one of the cooling channels. Furthermore, the preload of the rotor sleeve is generated or increased by a radially outward-acting bracing of the inner pole segments against the rotor sleeve, in particular by pressing the rotor carrier into the inner passage of the rotor body. The interrupter slots according to the invention mechanically decouple the inner pole segments from one another in the radially inner region and thereby enable the bracing of the inner pole segments against the rotor sleeve from the radially inside to the radially outward.

[0011] According to the invention, a higher preload of the rotor sleeve can be generated than in the prior art, since the fibers in the cured fiber composite can be subjected to higher loads than the fibers in the uncured fiber composite of the prior art. This allows the rotor sleeve to be made thinner in the radial direction, so that the maximum torque of the electric machine can be increased. Pressing the rotor arm into the rotor arm to generate the preload of the rotor sleeve can be completed in a shorter time during production than the winding and curing of the rotor sleeve directly on the rotor body in the prior art. Manufacturing costs can thus be significantly reduced.

[0012] The measures listed in the subclaims enable advantageous further developments and improvements of the rotor of the electric machine specified in the main claim.

[0013] It is particularly advantageous if the respective cooling channel is designed with regard to its radial position and / or cross-section and / or cross-sectional shape such that two rotor spokes are formed between the cooling channel and the two pocket legs of the adjacent magnet pockets, the longitudinal extent of which is each greater, in particular several times greater, than their width transverse to the longitudinal extent and which are bendable to clamp the magnets. In this way, a high preload can be generated in the rotor sleeve, thereby achieving high speed stability of the rotor and good clamping of the magnets.

[0014] It is also advantageous if the respective cooling channel has a radially outermost extension that extends radially to or beyond the radially innermost edges of the magnets of the adjacent magnet pockets. This creates rotor spokes with a large longitudinal extension, resulting in a large lever arm for generating the mechanical preload. This flexible design allows for significant deformation and thus a large mechanical preload.

[0015] It is also advantageous if the central area of ​​each magnetic pocket has a pocket bulge that bends off from the pocket legs of the respective magnetic pocket and extends radially inward. This creates rotor spokes with a large longitudinal extension, resulting in a large lever arm for generating the mechanical preload.

[0016] It is very advantageous if the circumferential extent of the respective cooling channel widens radially inwards, in particular if the cross-section of the cooling channel is triangular, V-shaped, trapezoidal, or bell-shaped. This results in sufficiently flexible rotor spokes. For example, the rotor spokes can become narrower radially inwards. It is also advantageous if a press fit is provided between the inner passage of the rotor body and the rotor carrier, so that the inner passage of the rotor body is widened when the rotor carrier is assembled, whereby the inner pole segments are clamped against the magnets and against the rotor sleeve by deformation, in particular bending, of the rotor spokes and / or by radial displacement of the inner pole segments in the radial direction. In this way, the preload in the rotor sleeve can be subsequently generated by the rotor carrier, for example by axially pressing in the rotor carrier.The cured composite material allows the rotor sleeve to be made thinner, thus increasing the maximum torque of the electric machine. The joint between the rotor carrier and the rotor body can be manufactured more easily than a joint between a prefabricated fiber composite sleeve and a rotor body in the prior art, as it involves two steel components as joining partners and not two different joining partners, and in particular, no fiber composite as the joining partner. The high preload in the rotor sleeve ensures that the outer pole segments fit tightly against the respective inner pole segments, resulting in very small air gaps in the magnet pockets. This further increases the maximum torque of the electric machine.

[0017] Advantageously, the rotor body can have a flattened portion on the outer circumference in the area of ​​the pole edges prior to assembly of the rotor carrier. These flattened portions are then pressed against the inner circumference of the rotor sleeve upon assembly of the rotor carrier. This allows for a nearly cylindrical outer circumference of the rotor body in the formed state, achieving a homogeneous stress distribution in the rotor sleeve. This enables greater rotor strength and thus a higher maximum speed.

[0018] It is also advantageous if each cooling channel is arranged with a partial cross-section in one rotor pole and the remaining partial cross-section in the adjacent rotor pole. This results in sufficiently flexible rotor spokes.

[0019] 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 bridge webs located on the outer circumference of the rotor body or can be designed as a separate pole body.

[0020] It is also advantageous if the rotor carrier is the rotor shaft, wherein the rotor shaft is a hollow shaft comprising a shaft cooling channel, wherein the respective cooling channel of the rotor body is fluidly connected to the shaft cooling channel via the respective interrupter slot and a radial opening of the rotor shaft. In this way, the interrupter slot additionally forms a flow connection to the shaft cooling channel, so that a cooling medium, for example, oil, can be directed into the cooling channels of the rotor via the shaft cooling channel, the radial openings, and the interrupter slots to cool the rotor.

[0021] According to an advantageous embodiment, the rotor sleeve comprises a fiber winding, in particular made of glass fiber or carbon fiber, and a cured composite material for embedding the fiber winding. The fiber composite sleeve can, for example, be prefabricated and mounted in the cured state on the rotor body without joining forces, in particular without being pressed onto it in the axial direction. In the case of a prefabricated rotor sleeve, the outer circumference of the rotor body does not need to be mechanically machined in preparation for joining the rotor sleeve, in contrast to the prior art, since the pressing is only created after the rotor sleeve and rotor body have been joined without applying force, by pressing the rotor carrier into the rotor body.Alternatively, the fiber winding of the fiber composite sleeve can be wound directly onto the rotor body with very low preload, the applied composite material can be cured on the rotor body, and the preload in the rotor sleeve can be subsequently generated by axially pressing in the rotor carrier.

[0022] The invention further relates to an electrical machine with a rotor according to the invention.

[0023] drawing

[0024] An embodiment of the invention is shown in simplified form in the drawing and explained in more detail in the following description. Fig. 1 shows a partial sectional view of a rotor according to the invention of an electrical machine and

[0025] Fig.2 a detailed view of a special design of the rotor body according to Fig.l before assembly of the rotor carrier.

[0026] Description of the embodiment

[0027] Fig.l shows a partial sectional view of a rotor of an electrical machine according to the invention.

[0028] The rotor 1 of an electric machine according to the invention has a rotor carrier 3, in particular a rotor shaft, which is rotatable about a rotor axis 2, a rotor body 4, in particular a rotor laminated core, arranged on the rotor carrier 3, and a rotor sleeve 5, in particular a fiber composite sleeve, surrounding the rotor body 4 on the outer circumference 4.1. The rotor body 4 has an inner passage 6 for the passage of the rotor carrier 3 and a plurality of rotor poles 7, each with a pole center 7.1. In at least one, in particular all, of the rotor poles 7, a V-shaped, C-shaped, or arc-shaped magnetic layer 8 of a plurality of magnets 9, in particular permanent magnets, is formed. The respective rotor pole 7 is divided by the respective magnetic layer 8 in the radial direction with respect to the rotor axis 2 into an inner pole segment 10 and an outer pole segment 11.In the respective rotor pole 7, between the respective outer pole segment 10 and the respective inner pole segment 11, a magnetic pocket 12 is formed. This magnetic pocket is provided for receiving the magnets 9 of the magnetic layer 8 and has a central region 12.1, which is located in particular in the region of the pole center 7.1 and is designed without a bridge web. The term “bridge webless” is to be understood as meaning that in the central region 12.1 there is no bridge web for bridging the magnetic pocket 12 or for connecting the outer pole segment 10 to the inner pole segment 11 of the respective rotor pole 7. The central region 12.1 is formed, for example, between two magnets 9 facing the pole center 7.1. The magnets 9 can be coated with insulation. Alternatively or additionally, separate insulation can be provided between magnet 9 and inner pole segment 10 and / or between magnet 9 and outer pole segment 11.

[0029] The respective outer pole segment 11 can be connected to the inner pole segment 10 of the same

[0030] The rotor pole 7 can be connected by means of bridge webs 13 located on the outer circumference 4.1 of the rotor body 4. Alternatively, the outer pole segments 11 can be designed as separate pole bodies by omitting the bridge webs 13. The outer pole segments 11 can have an additional magnet pocket (not shown) for accommodating at least one additional magnet.

[0031] The respective magnet pocket 12 has two pocket legs 12.2, which are provided for receiving the magnets 9 and are arranged on opposite sides with respect to the pole center 7.1, in particular mirror-symmetrically with respect to the pole center 7.1.

[0032] The rotor poles 7 are formed in the circumferential direction relative to the rotor axis 2 between two pole edges 7.2. The pole edges 7.2 are also referred to as the q-axis.

[0033] At the pole edges 7.2 of each rotor pole 7, an axial cooling channel 15 is provided, which is arranged between two pocket limbs 12.2 of two adjacent magnet pockets 12 and extends at least partially through the rotor body 4 in the axial direction relative to the rotor axis 2. The respective cooling channel 15 is arranged with a partial cross-section in one rotor pole 7 and with the remaining partial cross-section in the respective adjacent rotor pole 7.

[0034] The rotor body 4 has a hub section 4.2 radially inside the cooling channels 15, which is designed for mechanical coupling, i.e. for torque transmission, with the rotor carrier 3.

[0035] The rotor sleeve 5 has a mechanical prestress, 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.

[0036] According to the invention, the hub section 4.2 has a plurality of radial interrupter slots 16 along its circumferential extension, which extend radially from an inner circumference of the hub section 4.2 facing the rotor carrier 3 and each open or lead into one of the cooling channels 15. Furthermore, the invention provides that the preload of the rotor sleeve 5 is generated or increased by a radially outward-acting bracing of the inner pole segments 10 against the rotor sleeve 5, in particular by pressing the rotor carrier 3 into the inner passage 6 of the rotor body 4. The hub section 4.2 of the rotor body 4 is divided or separated into annular sections 17 by the interrupter slots 16. The interrupter slots 16 are each located, for example, on or near one of the pole edges 7.2 of the rotor poles 7.

[0037] The respective cooling channel 15 is designed with regard to its radial position and / or cross-section and / or cross-sectional shape such that two rotor spokes 18 are formed between the cooling channel 15 and the two pocket legs 12.2 of the adjacent magnet pockets 12, the longitudinal extent L of which is each greater, in particular several times greater, than the width B transverse to the longitudinal extent L and which are bendable to clamp the magnets 9. For example, a cross-sectional side of the respective cooling channel 15 facing the respective rotor spoke 18 forms the length of the respective rotor spoke 18.

[0038] The respective cooling channel 15 can have a radially outermost extension that extends radially up to or beyond the radially innermost edges of the magnets 9 of the respective adjacent magnetic pockets 12. Furthermore, the central region 12.1 of the magnetic pockets 12 can each have a pocket bulge 12.3 that bends from the pocket legs 12.2 of the respective magnetic pocket 12 and extends radially inward.

[0039] The extent of the respective cooling channel 15 in the circumferential direction can widen radially inward, for example by the cross section of the cooling channel 15 being triangular, V-shaped, trapezoidal or bell-shaped and aligned accordingly.

[0040] 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 widened during assembly of the rotor carrier 3, whereby the inner pole segments 10 are clamped against the magnets 9 and against the rotor sleeve 5 by deformation, in particular bending, of the rotor spokes 18 and / or by radial displacement of the inner pole segments 10 in the radial direction. For example, the rotor carrier 3 is pressed into the inner passage 6 of the rotor body 4 in the axial direction. In addition to the press connection between the rotor body 4 and the rotor carrier 3, a positive joint connection can be provided. 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.

[0041] The rotor shaft 3 can be a hollow shaft comprising a shaft cooling channel 20, wherein the respective cooling channel 15 of the rotor body 4 is fluidly connected to the shaft cooling channel 20 via the respective interrupter slot 16 and a radial opening 21 in the rotor shaft 3.

[0042] After pressing in the rotor carrier 3 and pre-tensioning the rotor sleeve 5, a potting compound can optionally be additionally filled into the magnet pockets 12.

[0043] Fig.2 shows a detailed view of a special design of the rotor body according to Fig.l before assembly of the rotor carrier.

[0044] The rotor body 4 can have a flattening 22 on the outer circumference 4.1 in the area of ​​the pole edges 7.3 before the assembly of the rotor carrier 3, which flattening is applied to the inner circumference of the rotor sleeve 5 by the assembly of the rotor carrier 3 with deformation of the bridge webs 13 and with radial displacement of the respective pole inner segment 10.

Claims

Claims 1. Rotor (1) of an electrical machine, with a rotor carrier (3) which can be rotated about a rotor axis (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) enclosing the rotor body (4), in particular a fiber composite sleeve, wherein the rotor body (4) has an inner passage (6) for the passage of the rotor carrier (3) and a plurality of rotor poles (7), each with a pole center (7.1), wherein in at least one, in particular all, of the rotor poles (7) a V-shaped, C-shaped or arc-shaped magnetic layer (8) of several magnets (9), in particular permanent magnets, is formed, wherein the respective rotor pole (7) is divided by the magnetic layer (8) in the radial direction with respect to the rotor axis (2) into an inner pole segment (10) and an outer pole segment (11), wherein in the respective rotor pole (7) between the outer pole segment (11) and the inner pole segment (10) a magnetic pocket (12) is formed which is provided for receiving the magnets (9) of the magnetic layer (8) and has a central region (12.1) which is located in particular in the region of the pole center (7.1) and is designed without bridge webs, wherein the respective magnetic pocket (12) has in each case two pocket legs (12.2) which are arranged on opposite sides with respect to the pole center (7.1), wherein at pole edges (7.2) an axial cooling channel (15) is provided for each of the rotor poles (7), which is arranged between two pocket legs (12.2) of two adjacent magnet pockets (12), wherein the rotor body (4) has a hub section (4.2) radially inside the cooling channels (15) which is provided for mechanical coupling to the rotor carrier (3), wherein the rotor sleeve (5) has a prestress, in particular for clamping the magnets (9) in the magnet pockets (12), characterized in that. - the hub section (4.2) has a plurality of radial interrupter slots (16) along its circumferential extension, each of which opens into one of the cooling channels (15), - the preload of the rotor sleeve (5) by a radially outward acting Tension of the inner pole segments (10) against the rotor sleeve (5) is generated or increased, in particular by pressing the rotor carrier (3) into the inner passage (6) of the rotor body (4). Rotor according to claim 1, characterized in that the respective cooling channel (15) is designed with regard to the radial position and / or the cross-section and / or the cross-sectional shape such that two rotor spokes (18) are formed between the cooling channel (15) and the two pocket legs (12.2) of the adjacent magnet pockets (12), the longitudinal extent (L) of which is each greater, in particular several times greater, than the width (B) thereof transversely to the longitudinal extent (L) and which are bendable for clamping the magnets (9). Rotor according to one of the preceding claims, characterized in that the respective cooling channel (15) has a radially outermost extent which extends in the radial direction to the radially innermost edges of the magnets (9) of the respectively adjacent magnet pockets (12) or beyond. Rotor according to one of the preceding claims, characterized in that the central region (12.1) of the magnet pockets (12) each has a pocket bulge (12.3) which bends away from the pocket legs (12.2) of the magnet pocket (12) and extends radially inward. Rotor according to one of the preceding claims, characterized in that the extent of the respective cooling channel (15) widens radially inward in the circumferential direction, in particular in that the cross-section of the cooling channel (15) is triangular, V-shaped, trapezoidal, or bell-shaped. Rotor according to one of the preceding claims, characterized in that 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 widened upon assembly of the rotor carrier (3), whereby the inner pole segments (10) are clamped against the magnets (9) and against the rotor sleeve (5) by deformation, in particular bending, of the rotor spokes (18) and / or by radial displacement of the inner pole segments (10) in the radial direction.Rotor according to one of the preceding claims, characterized in that the rotor body (4) has on the outer circumference (4.1) in the region of the pole edges (7.2) before the assembly of the rotor carrier (3) a flattened portion (22) which, as a result of the assembly of the rotor carrier (3), rests against the inner circumference of the rotor sleeve (5). Rotor according to one of the preceding claims, characterized in that the respective cooling channel (15) is arranged with a partial cross-section in one rotor pole (7) and with the remaining partial cross-section in the respectively adjacent rotor pole (7). Rotor according to one of the preceding claims, characterized in that the respective outer pole segment (11) is connected to the inner pole segment (10) of the same rotor pole (7) by means of bridging webs (13) located on the outer circumference (4.1) of the rotor body (4), or is each designed as a separate pole body. Rotor according to one of the preceding claims, characterized in that the rotor carrier (3) is the rotor shaft, wherein the rotor shaft (3) is a hollow shaft comprising a shaft cooling channel (20), wherein the respective cooling channel (15) of the rotor body (4) is fluidly connected to the shaft cooling channel (20) via the respective interrupter slot (16) and a radial opening (21) of the rotor shaft (3).Rotor according to one of the preceding claims, characterized in that the rotor sleeve (5) comprises a fiber winding, in particular made of glass fiber or carbon fiber, and a cured composite material for embedding the fiber winding. An electrical machine with a rotor (1) according to one of the preceding claims.

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