Rotor of an electric motor

Abstract

The invention relates to a rotor (1) of an electric motor, wherein the rotor (1) comprises a rotor assembly (2) and the rotor assembly (2) comprises a rotor yoke (3) and a plurality of rotor teeth (4), each rotor tooth (4) also carrying an excitation winding (5). The rotor assembly (2) here comprises an inner rotor assembly (6) designed as a single, continuous component and an outer rotor assembly (7) designed as a single, continuous component, wherein the inner rotor assembly (6) comprises at least the rotor yoke (3) of the rotor assembly (2) and the outer rotor assembly (7) comprises at least the tooth tips (9) of the rotor teeth (4). The inner rotor assembly (6) and the outer rotor assembly (7) are also connected to each other at least by a force-fit and / or positive-locking connection, which comprises at least one force-fit and / or positive-locking individual connection per rotor tooth (4).The individual connection of at least one rotor tooth (4) is designed as a head connection (13) between the tooth head (9) and a tooth shank (14) of the rotor tooth (4) and the individual connection of at least one rotor tooth (4) is designed as a yoke connection (15) between the rotor yoke (3) and a tooth shank (14) of the rotor tooth (4), wherein the individual connections of the rotor teeth (4) that are successive in the circumferential direction (11) are alternately designed as a head connection (13) or a yoke connection (15).

Description

[0001] The invention relates to a rotor of an electric motor, wherein the rotor comprises a rotor assembly and the rotor assembly comprises a rotor yoke and a plurality of rotor teeth, each rotor tooth also carrying an excitation winding. The rotor assembly further comprises an inner rotor assembly and an outer rotor assembly, both designed as a single, continuous component, wherein the inner rotor assembly comprises at least the rotor yoke of the rotor assembly and the outer rotor assembly comprises at least the tooth tips of the rotor teeth. Furthermore, the inner rotor assembly and the outer rotor assembly are connected to each other at least by a force-fit and / or positive-locking connection, which comprises at least one force-fit and / or positive-locking individual connection per rotor tooth. Here, the individual connection of at least one rotor tooth is designed as a head connection between the tooth tip and a tooth shank of the rotor tooth.

[0002] Externally excited synchronous machines are valued in many industrial applications for their precise controllability and high efficiency. A special variant of these machines is the salient-pole machine, distinguished by its characteristic design. However, this design also presents specific challenges, particularly regarding manufacturing and the mechanical strength of the rotor.

[0003] Externally excited synchronous machines, especially those with salient poles, require a significantly complex rotor design. Due to the high mechanical stresses and the associated need for high speed stability, the coil windings are wound using needle winding technology on a rotor core consisting of single-piece laminations. Despite these measures, the winding often remains the limiting factor in terms of speed stability. To overcome this challenge, the rotor slots are frequently sealed and potted in a complex process to increase stability and strength.

[0004] Another disadvantage of this design is the inhomogeneous air gap created by the slot openings and the contours of the pole shoes. This uneven air gap leads to increased air friction losses, which significantly reduces the machine's efficiency compared to machine types with a purely cylindrical rotor. These design features make salient-pole machines more complex and less efficient in certain operating ranges.

[0005] To address these problems, solutions are already known from the state of the art.

[0006] DE 10 2020 105 588 A1 refers to a rotor for a separately excited synchronous machine with permanent magnets, consisting of a rotor body constructed, in particular, from stacked, one-piece rotor laminations, a rotor winding, and several permanent magnets. The rotor body is formed by stacking or packing the rotor laminations. The rotor body also has several longitudinal grooves extending radially to the outer circumferential surface, in which both the rotor winding and the permanent magnets are arranged. The permanent magnets are positioned so that they form part of the outer circumferential surface. To fix the permanent magnets and secure them against radial centrifugal displacement during rotor rotation, a bandage made of fiber-reinforced plastic is applied to the outer circumferential surface. The bandage can be applied in such a way that it rests directly against the permanent magnets.However, it is also possible to have at least one intermediate layer between the bandage and the permanent magnets, made of a non-magnetic material, e.g., a plastic, in particular a synthetic resin. The bandage is applied by wrapping the rotor body, which is equipped with the rotor winding and the permanent magnets, with a fiber tape, possibly only after the intermediate layer has been applied.

[0007] DE 10 2016 222 481 A1 further describes a rotor for an electric machine comprising electrical coil assemblies, winding carriers that mechanically support the respective coil assembly and at least partially surround it on its radially outer side, and a central support element. The respective winding carrier is mechanically connected to the central support element via an anchoring element, in particular a tongue-and-groove system, which is positively embedded in the support element. The rotor also has a band made of glass- or carbon-fiber-reinforced plastic, by means of which the winding carrier is fixed in the rotor and thus, in particular, additionally supported. The band is arranged radially outside the at least one winding carrier. It is formed from a strip-shaped element and can be wound around the circumference of the rotor in the form of a spiral winding.As an alternative to the ribbon-like winding, such a bandage can also be formed by a cylinder that is shrunk onto the inner elements of the rotor, for example, a metallic cylinder, particularly made of a titanium alloy. Furthermore, internal cavities are provided by areas located circumferentially between the individual anchoring elements, through which coolant can flow to the respective coil assemblies. These individual internal cavities are fluidically connected to each other to form a larger coolant chamber. They are also connected to a tube interior of the central support element. Both the anchoring elements and the support element have openings for this purpose.

[0008] Furthermore, the generic patent DE 10 2020 107 830 A1 describes a rotor for a separately excited synchronous machine, wherein the rotor comprises a cylindrical base body with several axially extending connecting grooves. Several rotor teeth made of a magnetic material, arranged radially on the base body, are inserted into the connecting grooves, forming an annular shape in the radial direction. An electrical winding is applied around each rotor tooth. The winding can be applied to the rotor teeth before the rotor teeth are joined to the base body. This allows for a higher copper fill factor in the rotor, since, due to the lack of a provision for a needle or tool, the winding area of ​​each rotor tooth can be completely filled with wire. In addition, adjacent rotor teeth can be bonded together using a baking varnish, in particular by full-surface bonding.In the radial direction, a sleeve made of a non-magnetic material, in particular a carbon fiber reinforced plastic, is arranged around the rotor teeth. The sleeve can be applied to the ring-shaped end cap, thus holding the rotor teeth to the base body and absorbing centrifugal forces acting on the base body and the rotor teeth at high rotational speeds.

[0009] However, a significant disadvantage of the aforementioned solution is that the large number of rotor parts results in a very high assembly effort and makes the rotor susceptible to tolerance differences, which can negatively affect the efficiency and smooth running of an electric motor containing the rotor.

[0010] German patent DE 10 2011 121 793 A1 describes an electric motor with a simple, easy-to-manufacture rotor design. The rotor lamination stack is star-shaped with radial sections onto which prefabricated individual windings, including a hollow winding carrier, are slid from the outside. At the outer end, each radial section has a dovetail-like contour into which pole heads engage in a form-fitting manner and are heat-shrinkable if necessary, thus radially limiting the windings and ensuring mechanical rigidity. Between adjacent pole heads are cover plates made of non-magnetic material, featuring an inwardly projecting blade for electrical isolation of the individual windings and cover wings that prevent the winding wires from migrating out and, together with the pole heads, form a container for potting compound.End caps close off the rotor on both sides; they are cylindrical on the outside and polygonally contoured on the inside, supporting the flat outer surfaces of the winding carriers and providing filling openings for the potting compound. The potting compound encases the windings and carriers, increasing mechanical stability, damping vibrations, and improving heat dissipation. Overall, the modular design with slide-on windings, pole heads, cover slides, and end caps allows for easy assembly while ensuring secure guidance and cooling of the windings.

[0011] DE 10 2019 218 603 A1 discloses a rotor with a rotor shell that is at least partially form-fitting and remains permanently on the rotor as a lost intermediate mold. During the casting of the rotor winding with low-viscosity thermoset resins, the shell seals the mold and protects it from contamination. The rotor winding is essentially completely infiltrated with cured plastic, which increases its centrifugal strength and heat dissipation. The rotor shell consists of a pot-shaped section and a lid-like section, has a cylindrical outer surface with optional radially inward-facing indentations in the pole gaps, can have integrated cooling channels with sealing edges, and is preferably made of filled PPS or thin-walled stainless steel. Ring-shaped reinforcing elements at the rotor ends increase mechanical strength, and a circumferential thickening facilitates easy balancing.Also described are seals on the shaft, feeders for resin injection, and a manufacturing process with the steps of applying the shell, inserting it into the mold, infiltrating and curing, and then demolding.

[0012] JP 2015-167432 A discloses an integral machine core, in particular a stator, with a cylindrical core body and alternating first and second teeth onto which coils are pushed from the inside. The first coil has circumferentially extending metallic extensions that bear against the inner surfaces of adjacent teeth and engage via claws in corresponding recesses, thus enabling more turns and a smaller coil spacing. Assembly is carried out first with the second coils and then with the first coils, thereby avoiding interference fits in the core. The result is a higher magnetic flux density and reduced losses.

[0013] JP 2020 - 188 637 A describes a rotor for a separately excited synchronous machine. The rotor lamination stack is formed as a ring with radially inward-projecting teeth, all made from a single piece. Integrated drivers at the tooth ends engage in longitudinal slots on the rotor shaft. The field windings are conveniently applied to the teeth from the radial inner side, and the core is then simply fitted onto the shaft, significantly simplifying assembly and reducing costs. The outer ring securely holds the windings in place at high speeds. In one embodiment, the shaft features an axial cooling channel with radial branches that direct coolant directly into the slots leading to the windings, thus improving cooling along the entire length of the rotor.

[0014] JP 2001-69705 A discloses a motor armature core in which a laminated toothed ring is first wound openly and then inserted into a cylindrical shell, thus increasing the winding fill factor and reliably holding the conductors in the slots. The shell is optionally made of sintered Fe-Si or a pressed, resin-bonded soft magnetic material and features slot areas with increased magnetic reluctance, which guides the flux, increases efficiency, and reduces cogging torque. Variants described include separate locking pieces at the tooth tips instead of the shell, different slot geometries (including inclined or through slots), and shells with greater axial length to further increase flux and torque and reduce eddy current losses.

[0015] DE 10 2020 111 542 A1 describes a method for potting an FSM rotor by injection molding a heated potting compound into the rotor winding while it is vertically oriented between two mold plates. Radial sealing on the rotor side is achieved by a sleeve or bandage made of fiber-reinforced plastic, either slipped onto the rotor or by displacement elements inserted into the rotor slots. The end faces are sealed with sealing caps. A low-viscosity, fast-curing, and preferably highly filled resin compound penetrates even narrow gaps in orthocyclic windings and can be introduced via multi-point injection. The cavityless injection mold reduces complexity and allows for short cycle times. The potted rotor achieves high mechanical stability and can optionally be oven-cured. With a suitable design, the sleeve can be removed.

[0016] The KR 10 2017 0 060 501 A is a rotor for a separately excited machine with a two-part core consisting of an inner core with teeth and an outer core that encircles the rotor. Pre-assembled coils are inserted from the outside into the toothed windows of the inner core, and the outer core is then axially pressed on, thus completely enclosing the coils and preventing leakage at high speeds. The outer core has alternating thick and thin sections, which increases the pole arc, improves torque, and reduces torque ripple. Assembly simply involves inserting the coils and press-fitting the outer core. This increases the fill factor and allows for a smaller rotor design. Variants include ferritic permanent magnets in the teeth to increase flux, as well as zigzag-shaped leakage-stop grooves in the thin-walled sections of the outer core to minimize leakage.

[0017] DE 10 2016 223 509 A1 further discloses a rotor with a two-part laminated core, in which an inner cylindrical core has radially outwardly open grooves for the windings, and an outer bushing-shaped core closes these grooves. Both parts are positively connected via a dovetail joint or force-fit via an interference fit and can be designed as baked-on lacquer or stamped stacks. The outer core can have circular, rectangular, or sinusoidal pole contours and can optionally extend to the star disks, thereby supporting the winding heads and eliminating the need for solid support rings.

[0018] DE 10 2021 119 140 A1 describes a rotor for a separately excited electric machine with a yoke formed from laminated cores and pole shafts onto which pre-wound windings are mounted transversely to the axis of rotation, and subsequently, separate pole shoes are attached by positive locking, force locking, or material locking. Gaps between adjacent pole shoes are closed axially, at least partially, by webs and / or a circumferentially mounted tube, preferably made of non-conductive fiber-reinforced material, to stabilize the pole shoe ends under centrifugal force and to keep the air gap small. An asymmetrically provided flux barrier with a closed opening, located only on one side of the pole tooth in the pole shoe, reduces harmonics and improves machine performance. The manufacturing process comprises punching and stacking the laminations, pre-winding and mounting the windings, and attaching the pole shoes and web or tube.

[0019] Furthermore, DE 10 2019 218 628 A1 discloses a rotor for an electric machine with a rotor shaft and several rotor legs, each of which has an excitation coil attached. Each rotor leg is assigned a pole shoe, and the pole shoes are connected to form a pole shoe unit. The pole shoes are preferably constructed as laminated stacks, with annular or segmented laminations connected or separated by connecting areas or gaps. These connecting areas can be demagnetized by remelting. Gaps between pole shoes can be closed by slot closure elements or plastic overmolding, enabling a stable, easy-to-assemble, and component-optimized design. The connection between the pole shoes and rotor legs is preferably positive-locking or force-locking, for example, by press fits or dovetail profiles.The manufacturing process involves connecting the rotor shaft to the rotor legs, fitting excitation coils, and pressing the pole shoe unit onto the legs.

[0020] Against this background, the invention is based on the objective of designing the rotor of the type mentioned above in such a way that the assembly effort for the rotor and its susceptibility to tolerance differences are minimized.

[0021] This problem is solved with a rotor according to the features of claim 1. The dependent claims relate to particularly advantageous further developments of the invention.

[0022] According to the invention, a rotor of an electric motor, in particular of a separately excited synchronous machine, is provided, wherein the rotor comprises a rotor assembly and the rotor assembly a rotor yoke, as well as a plurality of rotor teeth extending radially outwards, in particular from the rotor yoke, and / or in particular spaced uniformly apart from one another in the circumferential direction of the rotor. Each rotor tooth carries an excitation winding and / or an excitation coil.

[0023] Furthermore, according to the invention, the rotor assembly comprises an inner rotor assembly, in particular radially inner, designed as a continuous, e.g., one-piece and / or integral component, and an outer rotor assembly, in particular radially outer, arranged on and / or on the inner rotor assembly, designed as a continuous, e.g., one-piece and / or integral component. The outer rotor assembly thus surrounds the inner rotor assembly, in particular radially and / or circumferentially, at least partially.

[0024] The inner rotor assembly comprises at least one rotor yoke, and the outer rotor assembly comprises at least the tooth tips or pole shoes of the rotor teeth. Furthermore, the inner and outer rotor assemblies are connected to each other at least by one, preferably exclusively force-fit and / or form-fit connection. This overall connection includes at least one, in particular exclusively force-fit and / or form-fit, individual connection per rotor tooth.

[0025] Because the rotor package consists of only two components, namely the outer rotor package and the inner rotor package, assembly is significantly simplified, especially compared to rotors where the rotor package consists of more than two, especially a large number of, components or overall components.

[0026] While it would be conceivable in principle for the inner rotor stack and / or the outer rotor stack to be formed in one piece, i.e., from a single body rather than from several interconnected or joined individual components, preferably the rotor stack, and / or the outer rotor stack, consist of individual components connected to one another, in particular by force-fit, form-fit, and / or material-fit connections. These individual components are rotor lamellae and / or partial rotor lamellae joined together, in particular by stacking, e.g., stamping stacking and / or adhesive stacking, to form the inner rotor stack and / or the outer rotor stack. Furthermore, it is conceivable that at least one cooling channel, extending axially (i.e., in the longitudinal direction of the rotor), is formed in the inner rotor stack, particularly in the rotor yoke, and / or in the outer rotor stack.

[0027] In a particularly advantageous embodiment of the invention, the rotor also features a casing that rests against the rotor assembly, which is preferably made of a magnetic, and preferably a soft magnetic, material, and / or radially encloses the rotor teeth at least partially. The casing preferably consists of a non-magnetic and / or non-ferromagnetic material, such as a fiber-reinforced composite material, for example, glass fiber-reinforced or carbon fiber-reinforced plastic. The casing can be designed as a bandage wrapped around the rotor assembly, for example, from rovings or fiber loops of fiber-reinforced composite material, preferably impregnated with epoxy resin. However, it is preferred that the casing be designed as a sleeve. This increases the reproducibility of the joining process between the sleeve-designed casing and the rotor assembly, particularly compared to a manually applied bandage.Furthermore, the use of a sleeve allows for simplified automation of the joining process. Another advantage is the homogeneous air gap of the rotor-bearing electric motor, which is provided by the casing. This uniform air gap leads to reduced air friction losses, making the efficiency of the electric motor comparable to machine types with a purely cylindrical rotor.

[0028] This further development incorporates a transition fit between the sleeve-shaped casing and the rotor assembly. This offers the advantage of ensuring a secure connection between the rotor assembly and the sleeve-shaped casing without causing damage during assembly. The connection between the rotor assembly and the sleeve should be designed to prevent any relative movement between the two components after assembly, particularly during subsequent manufacturing steps. A final bond between the rotor assembly and the sleeve could be achieved by injecting potting compound into the rotor assembly.

[0029] An embodiment of the invention is further considered advantageous if the outer rotor assembly is axially divisible and / or subdivided into longitudinal segments, wherein the tooth heads, preferably exclusively in one, and in particular a first, subset of these longitudinal segments, are integrally and / or materially bonded to one another at least in the circumferential direction via connecting webs extending in the circumferential direction. An integral design of the tooth heads and connecting webs is preferred. Thus, the tooth heads would be separated from one another, preferably exclusively in a further, and in particular a second, subset of these longitudinal segments, particularly only in the circumferential direction. Each tooth head of a rotor tooth would, of course, still always be axially connected.

[0030] This results in a rotor assembly in which the tooth heads and / or rotor teeth are axially connected to each other in the circumferential direction via the connecting webs. Longitudinal segments in which the tooth heads are connected to each other in the circumferential direction and longitudinal segments in which the tooth heads are separated from each other in the circumferential direction could alternate axially.

[0031] Although the connecting webs create a magnetic short circuit between the rotor teeth in the relevant longitudinal segments or subsets thereof, this advantageously allows for the provision of a rotor outer assembly designed as a single, continuous, and in particular one-piece, component, in which the tooth tips and / or the rotor teeth are held together by the connecting webs. This significantly reduces assembly effort and / or simplifies, in particular, an automated assembly process for the rotor assembly and / or the rotor.

[0032] Preferably, as already explained, the rotor assembly is formed from rotor lamellae and / or partial rotor lamellae, wherein each longitudinal segment would be formed from at least one rotor lamella and / or partial rotor lamella. The first subset of longitudinal segments, in particular, which have connecting webs between the tooth tips, would thus be formed from one-piece rotor lamellae, i.e., not assembled from individual components, which, as is common in the prior art, would be formed, in particular by stamping, as a blank from an electrical steel sheet. These rotor lamellae would have sections forming at least the tooth tips, and optionally also the entire rotor tooth, as well as sections forming the connecting webs.The further, and in particular the second, subset of longitudinal segments, in which the tooth tips of the rotor teeth are separated from one another, would be formed by partial rotor lamellae, wherein a partial rotor lamella comprises at least one tooth tip of a rotor tooth, and optionally also an entire rotor tooth, forming a section. Several such partial rotor lamellae lying in a cross-sectional plane or position of the rotor stack, and not joined or connected to one another, would form a – hypothetical – rotor lamella of the outer rotor stack. Each partial rotor lamella would again be formed in one piece, i.e., not assembled from individual components. As is common in the prior art, this would be formed, in particular, by stamping as a blank from an electrical steel sheet.

[0033] The proportion of the first subset of longitudinal segments in the rotor assembly would be at most 30%, preferably at most 20%, and particularly preferably at most 10%. This proportion would be, in particular, a proportion of the number of rotor blades in the first subset relative to their total number and / or a length proportion relative to the total length of the rotor assembly.

[0034] According to the invention, the individual connection of at least one rotor tooth is also designed as a head connection between the tooth head and a tooth shank of the rotor tooth. A tooth shank of the respective rotor tooth would belong to the inner rotor assembly and preferably form a continuous, in particular one-piece, component with the rotor yoke. In principle, according to the invention, the individual connection of not every rotor tooth could be designed as a head connection, or the individual connections of several rotor teeth could be designed as a head connection. In particular, if not every individual connection were designed as a head connection according to the invention, the outer rotor assembly would be shaped as a kind of head ring, which essentially comprises the tooth heads.This would be advantageous in that it would result in a rotor outer package with a low mass, especially in relation to the rotor inner package, and / or simplified handling, thus reducing the assembly effort for the rotor and / or the rotor package during assembly, for example on a stationary rotor inner package.

[0035] Furthermore, according to the invention, the individual connection of at least one rotor tooth is designed as a yoke connection between the rotor yoke and a tooth shank of the rotor tooth. A tooth shank of the respective rotor tooth would belong to the outer rotor assembly and preferably, together with the associated tooth head, form a continuous, in particular one-piece, overall component with the outer rotor assembly. In principle, according to the invention, the individual connection of not every rotor tooth could be designed as a yoke connection, or the individual connections of several rotor teeth could be designed as a yoke connection. In particular, if not every individual connection were designed as a yoke connection according to the invention, the inner rotor assembly would be shaped like a hollow cylinder and / or would essentially comprise the rotor yoke.This would prove advantageous, as it would result in an inner rotor assembly with a lower mass, especially compared to the outer rotor assembly. This would simplify handling, which in turn would significantly reduce assembly effort, particularly when installing it on a stationary outer rotor assembly.

[0036] The design of the rotor package, which is separated via the inner rotor package and the outer rotor package, and in particular the design of the individual connection of at least one rotor tooth as a head connection and / or a yoke connection, also offers the advantage that the application of the excitation winding to the respective rotor tooth, in particular the tooth shank of the rotor tooth, is significantly simplified.

[0037] In one embodiment of the invention, it is advantageously designed that each of the excitation windings is configured as a pre-formed plug-in coil, which is pushed onto the toothed shank of a rotor tooth. This makes it possible to significantly minimize the manufacturing time for the excitation windings, since they can thus be manufactured on simple, high-speed coil winding machines, especially compared to needle winding machines.

[0038] Furthermore, it is generally possible to increase the copper fill factor of the rotor, since a partial space of the gap, in particular the slot openings between the rotor teeth, which must be kept free for a needle winding process, can also be filled with correspondingly additional windings of the excitation windings.

[0039] Based on the design of individual connections as head connections or yoke connections, the invention provides that the individual connections of the rotor teeth, corresponding to two successive and / or adjacent rotor teeth in the circumferential direction, are alternately designed as head connections or yoke connections. In this way, a tooth shank of these rotor teeth belongs alternately to the outer rotor stack and the inner rotor stack in the circumferential direction, whereby the excitation windings can be and / or are applied to the tooth shanks of the outer rotor stack and the inner rotor stack during the assembly of the rotor, which in particular involves axial joining, preferably axial sliding of the outer rotor stack and the inner rotor stack.In this process, the excitation windings, designed as plug-in coils, are pushed or plugged onto the toothed shafts of the inner rotor stack, particularly from the outside towards the rotor yoke, and onto the toothed shafts of the outer rotor stack, particularly from the inside towards the tooth tips. This makes it possible, in particular, to achieve a maximum copper fill factor even with the same radially shaped cross-section of the plug-in coils.

[0040] It is also advantageous if, in a further development of the invention, a cross-section formed radially, i.e., perpendicular to a longitudinal axis of the rotor, is shaped differently from each other, particularly with regard to area and / or shape, corresponding to two successive and / or adjacent excitation windings in the circumferential direction. In this way, a high or maximum copper fill factor can be achieved even in a rotor design where the tooth shanks of the rotor teeth belong entirely or to a large extent to either the inner or outer rotor stack. The cross-sections of the excitation windings, which are particularly designed as plug-in coils, are designed such that they do not interfere with or block each other when applied, particularly when plugged onto the tooth shanks.

[0041] An embodiment of the invention is further considered advantageous if at least one area of ​​the rotor, preferably bounded radially at least by the casing and / or connecting webs, is filled, and preferably encased, with a potting compound, particularly via at least one flux channel formed in the rotor. This advantageously increases both the mechanical stability of the rotor and provides improved smooth running and optimized thermal behavior of the rotor, particularly due to the improved thermal connection of the excitation windings via the potting compound. In addition to the casing and / or the connecting webs, the excitation windings and / or the rotor teeth can also bound the area filled with potting compound. The aforementioned flux channel would preferably be formed extending at least axially within the rotor.The area or areas are filled with the potting compound by potting in a potting process, in particular injection molding or injection compression molding, which is also known as transfer molding.

[0042] A further advantage arises from the embodiment of the invention if at least one balancing disc is provided at each axial and / or end face of the rotor assembly, wherein at least one, preferably one, of the balancing discs is designed as a cast balancing disc made of a potting compound and integrally molded onto the rotor assembly and / or the casing. This advantageously leads to a reduction in the number of rotor components, which in turn results in cost optimization. Furthermore, the manufacturing process of the rotor can be made more efficient, since integrating the molding of the cast balancing discs into the potting process of the area or areas eliminates several manufacturing steps. This not only saves time but also reduces assembly effort and minimizes potential sources of error, ultimately leading to higher production quality and reliability of the rotor.

[0043] A further advantageous embodiment of the invention is characterized by the fact that at least one balancing disc, made of a metal, for example aluminum, is provided at each longitudinal and / or end face of the rotor assembly, wherein at least one, preferably one, of the balancing discs has at least one sprue opening and / or at least one vent opening. With such a design, filling, in particular potting, the areas could be carried out essentially without the use of a mold. The partial retention of the potting compound in the sprue and / or vent opening further contributes to increased mechanical stability, improved smooth running, and optimized thermal behavior.

[0044] The invention allows for numerous embodiments. To further illustrate its basic principle, some of these are shown in the drawing and described below. The drawing shows in Fig. 1, Fig. 2 a first embodiment of the rotor in two axially different sections; Fig. 3 a second embodiment of the rotor in section with yoke and head connections between rotor inner and rotor outer package; Fig. 4 a schematic top view of an outer rotor package of the rotor with longitudinal segments; Fig. 5 showing a schematic longitudinal section of a rotor with end balancing discs, sprue and vent openings; Fig. 6 a schematic longitudinal section of a rotor with potting balancing discs.

[0045] From the Fig. 1 and Fig. Figure 2 shows a schematic half-representation of a radial section through an electric motor 26, which includes the stator 32 and an embodiment of the rotor 1 according to the invention arranged within the stator 32.

[0046] The rotor 1 comprises the rotor assembly 2, and this assembly comprises the inner rotor assembly 6 and the outer rotor assembly 7 arranged on and / or attached to the inner rotor assembly 6. In this embodiment of the rotor 1, the inner rotor assembly 6 essentially comprises the rotor yoke 3, and the outer rotor assembly 7 essentially comprises the rotor teeth 4 of the rotor assembly 2 and / or the rotor 1, each consisting of the tooth head 9 and the tooth shank 14.

[0047] Both the inner rotor assembly 6 and the outer rotor assembly 7 are designed as separate, yet interconnected, components and are joined together by a force-fit and / or form-fit connection. This connection, in turn, comprises a force-fit and / or form-fit individual connection for each rotor tooth 4. The individual connection of each rotor tooth 4, designed in detail as a dovetail joint, is implemented as a yoke connection 15 between the rotor yoke 3 and the tooth shank 14 of the rotor tooth 4.

[0048] The inner rotor stack 6 is composed of axially arranged rotor lamellae 28, and the outer rotor stack 7 is composed of axially arranged rotor lamellae 28 and axially arranged partial rotor lamellae 27, which are joined together in particular by stamping and / or adhesive bonding, e.g. by means of a baking varnish. From the two in the Fig. 1 and Fig. The two sections shown each depict a layer of rotor blades 28 and / or partial rotor blades 27 within the rotor assembly 2. The Fig. 1 and Fig. 2, that the inner rotor assembly 6, which essentially comprises the rotor yoke 3, is formed from identically shaped, one-piece rotor lamellae 28, i.e., not assembled from individual components, which, as is customary in the prior art, are formed in particular by stamping as a blank from an electrical steel sheet. The outer rotor assembly 7, which essentially comprises the rotor teeth 4, is formed, on the other hand, from one-piece rotor lamellae 28 and several, each also one-piece, partial rotor lamellae 27, which, however, are separated from one another within a layer and are uniformly spaced from one another in the circumferential direction 11. Thus, the partial rotor lamellae 27 of one layer form an imaginary rotor lamella 28. In addition, the partial rotor lamellae 27 are axially aligned with the partial rotor lamellae 27 and the sections of the rotor lamellae 28 forming the rotor teeth 4 of the other layers of the outer rotor assembly 7, so that these accordingly form the rotor teeth 4.To ensure that the rotor outer package 7 is designed as a coherent overall component, the rotor outer package 7 is axially in, in the . Fig. 4 longitudinal segments shown in more detail, 8 subdividable and / or subdivided, wherein, as the Fig. 2 and Fig. As can be seen from Figure 4, the tooth heads 9 in a subset of these longitudinal segments 8 are connected to each other via the connecting webs 12 extending in the circumferential direction 11. Through this connection and the axial connection of the rotor lamellae 28 and partial rotor lamellae 27, the outer rotor assembly 7 is formed as a single, coherent component, which is particularly easy to handle, for example, for the assembly of the rotor 1 and / or the rotor assembly 2, especially by machine.

[0049] Each rotor tooth 4, specifically the tooth shank 14 of the rotor tooth 4, carries the excitation winding 5, wherein each of the excitation windings 5 ​​in this embodiment of the rotor 1 is designed as a plug-in coil 16 and is pushed onto the tooth shank 14 of the rotor tooth 4. In particular, during the assembly of the rotor 1, all the plug-in coils 16 are pushed or plugged onto the tooth shanks 14 of the rotor teeth 4 from the inside, i.e., towards the tooth tips 9. In order to achieve the highest possible copper fill factor in the rotor 1, the cross-sections 17 of the excitation windings 5, which are arranged successively in the circumferential direction 11 and are designed here as plug-in coils 16, differ from one another in terms of their area and shape. In this way, they do not interfere with or block each other during application, i.e., sliding or plugging onto the tooth shanks 14. It should be mentioned here that the Fig. 1 and Fig. The two cross-sections 17 shown are to be understood as essentially exemplary. In particular, cross-sections 17 were chosen here through which the same excitation and / or the same magnetic flux would be generated for each rotor tooth 4.

[0050] To ensure high mechanical stability of the rotor 1, particularly against the centrifugal forces acting on it during operation of the electric motor 26, the rotor 1 also features a sleeve-like casing 10 that rests against the rotor assembly 2 and / or radially surrounds the rotor teeth 4. Furthermore, the areas 18 of the rotor 1, especially the groove openings between the rotor teeth 4, which are bounded by the casing 10 and the connecting webs 12, and in this embodiment also by the excitation windings 5, are filled with the potting compound 20. This further increases the mechanical stability of the rotor 1, resulting in particularly high final stability. The thermal connection of the excitation windings 5 ​​is also improved, thus increasing heat dissipation from the interior of the rotor 1.To fill the areas 18, an axially extending flow channel 19 is also formed radially below the casing 10 in each area 18 of the rotor 1.

[0051] To cool the in the Fig. 1 and Fig. In addition, in the rotor 1 shown in Figure 2, a cooling channel 29 is formed in the rotor inner package 6 for each excitation winding 5, in particular for each plug-in coil 16, which extends at least partially axially through the rotor inner package 6.

[0052] The Fig. Figure 3 shows a further embodiment of the rotor 1 in a radial section, schematically divided into two parts. This embodiment differs from the preceding embodiment essentially in that the individual connections of the successive rotor teeth 4 in the circumferential direction 11 are alternately designed as head connections 13 or yoke connections 15. In this further development, the head connections 13 are specifically designed as T-connections or hammerhead connections. This means that the tooth shanks 14 of the rotor teeth 4 also alternately belong to the inner rotor stack 6 or the outer rotor stack 7. This advantageously allows the excitation windings 5, designed as plug-in coils 16, to be slid or plugged onto the tooth shanks 14 of the inner rotor stack 6 either from the outside, i.e., towards the rotor yoke 3, or from the inside, i.e., towards the tooth heads 9, onto the tooth shanks 14 of the outer rotor stack 7.Thus, even with the same radially shaped cross-section 17 of the plug-in coils 16, a maximum copper fill factor can be achieved. The additional partial space 30 between the rotor teeth 4, which can be filled with windings and would otherwise have to be kept free for a needle winding process, is shown here with a dashed line.

[0053] As previously explained, the Fig. 4 the axial subdivision of the rotor outer assembly 7 into longitudinal segments 8, wherein the tooth tips 9 of the rotor teeth 4 are connected to each other in a subset of these longitudinal segments 8 via the connecting webs 12 extending in the circumferential direction 11. Furthermore, the structure of the rotor outer assembly 7 from rotor lamellae 28 and partial rotor lamellae 27 is illustrated again.

[0054] The embodiment of rotor 1 of the Fig. 5 has a conventionally designed balancing disc 22 at each axial end 21 of the rotor assembly 2, wherein the gate openings 24 are formed in one of the balancing discs 22 and the vent openings 25 are formed in the other balancing disc 22, which is arranged at the axially opposite end 21. The gate openings 24 are used to transfer the material, which is particularly important in the Fig. 1 and Fig. The areas 18 shown above are potted with the potting compound 20, so that the rotor 1 has a high mechanical stability, especially via the casing 10 and the areas 18 filled with potting compound 20.

[0055] In a further embodiment of rotor 1 of the Fig.A balancing disc 22 is also arranged at each axial end 21 of the rotor assembly 3. However, one of the balancing discs 22 is formed as a cast balancing disc 23 from the casting compound 20, which is integrally molded onto the rotor assembly 2 and the casing 10. This formation occurs simultaneously with the casting of the areas 18 with the casting compound 20. The mold 31 is used for casting the areas 18 and for forming the cast balancing discs 23, with the casing 10 of the rotor 1 forming part of the mold 31. Reference symbol list 1 Rotor 2 rotor package 3 Rotor yoke 4 rotor teeth 5 Excitation development 6 Rotor inner package 7 Rotor outer package 8 Longitudinal segment 9 Tooth head 10 Sheathing 11 Circumferential direction 12 Connecting bridge 13 Head connection 14 Tooth shaft 15 yoke connection 16 Plug-in coil 17 Cross section Area 18 19 River canal 20 potting compound 21 End 22 Balancing disc 23 Potting balancing disc 24 Gate opening 25 vent opening 26 Electric motor 27 partial rotor blades 28 rotor blades 29 Cooling channel 30 sub-rooms 31 mold 32 Stator

Claims

[1] Rotor (1) of an electric motor, wherein the rotor (1) comprises a rotor assembly (2) and the rotor assembly (2) comprises a rotor yoke (3) and a plurality of rotor teeth (4), wherein each rotor tooth (4) carries an excitation winding (5) and the rotor assembly (2) comprises an inner rotor assembly (6) designed as a single, continuous component and an outer rotor assembly (7) designed as a single, continuous component, wherein the inner rotor assembly (6) comprises at least the rotor yoke (3) of the rotor assembly (2) and the outer rotor assembly (7) comprises at least the tooth tips (9) of the rotor teeth (4), wherein the inner rotor assembly (6) and the outer rotor assembly (7) are connected to each other at least by a force-fit and / or form-fit connection, which comprises at least one force-fit and / or form-fit individual connection per rotor tooth (4) and the individual connection of at least one rotor tooth (4) is a head connection (13) between the tooth tip (9) and a tooth shank (14) of the rotor tooth (4) is designed,characterized by , that the individual connection of at least one rotor tooth (4) is designed as a yoke connection (15) between the rotor yoke (3) and a tooth shank (14) of the rotor tooth (4), wherein the individual connections of the rotor teeth (4) that are successive in the circumferential direction (11) are alternately designed as a head connection (13) or yoke connection (15). [2] Rotor (1) according to claim 1, characterized by , that the rotor (1) has a casing (10) that abuts the rotor pack (2) and / or radially at least partially encloses the rotor teeth (4), wherein a transition fit is formed between the casing (10), which is designed as a sleeve, and the rotor pack (2). [3] Rotor (1) according to claim 1 or 2, characterized by, that the rotor outer package (7) is axially divisible and / or subdivided into longitudinal segments (8), wherein the tooth heads (9) in a subset of these longitudinal segments (8) are connected to each other via connecting webs (12) extending in the circumferential direction (11). [4] Rotor (1) according to at least one of the preceding claims, characterized by , that each of the excitation windings (5) is designed as a plug-in coil (16) which is pushed onto a toothed shaft (14) of a rotor tooth (4). [5] Rotor (1) according to at least one of the preceding claims, characterized by , that a cross-section (17) of each successive excitation winding (5) is shaped differently in the circumferential direction (11). [6] Rotor (1) according to at least one of the preceding claims, characterized by, that at least one area (18) of the rotor (1) bounded by the casing (10) and / or connecting webs (12), in particular via at least one flow channel (19) formed in the rotor (1), is filled with a potting compound (20). [7] Rotor (1) according to at least one of the preceding claims, characterized by , that at least one balancing disc (22) is provided at each axial end (21) of the rotor package (2), wherein at least one, preferably one of the balancing discs (22) is formed as a potting balancing disc (23) formed on the rotor package (2) and / or the casing (10) from a potting compound (20). [8] Rotor (1) according to at least one of the preceding claims, characterized by , that at least one balancing disk (22) is provided at each axial end (21) of the rotor package (2), wherein at least one of the balancing disks (22) has at least one gate opening (24) and / or at least one vent opening (25).

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