Rotor for a separately excited electric machine and method for manufacturing a rotor

Abstract

Rotor (1) for a separately excited electric machine (2), comprising a rotor body (4) formed from a plurality of stacked rotor laminations (3), which forms several axially extending grooves (5) for receiving a winding (6), and the rotor laminations (3) having a first group of radially extending polars (9) which are monolithically formed with the rotor laminations (3), wherein the rotor body (4) further comprises a second group of radially extending polars (10) which are positively connected and / or force-fit and / or materially bonded to the rotor body (4) and the winding (6) is designed as a ring which is inserted into the slots (5) in a meandering manner, forming winding heads (20a,20b) that project axially from the rotor body (4) and partially encloses the polars (9) of the first group and the polars (10) of the second group, so that each of the polars (9,10) has only one winding head (20a,20b), wherein when current is applied to the windings (6) rotor poles (7) are formed, wherein the winding (6) is penetrated by a plurality of cooling tubes (11) extending axially through the winding (6), the cooling tubes (11) being hydraulically coupled to a balancing disk (12) at the winding heads (20a, 20b), so that during operation of the rotor (1) cooling fluid (13) exiting axially from the cooling tubes (11) can exit radially outwards from the balancing disk (12) via a fluid guidance structure (14) formed in the balancing disk (12).

Description

[0001] The present invention relates to a rotor for a separately excited electric machine, comprising a rotor body formed from a plurality of stacked rotor laminations, which forms several axially extending grooves for receiving a winding, and the rotor laminations having a first group of radially extending polars which are monolithically formed with the rotor laminations, wherein the rotor body further comprises a second group of radially extending polars which are positively and / or frictionally and / or materially bonded to the rotor body, and the winding is formed as a ring which is inserted into the grooves in a meandering manner, forming winding heads projecting axially from the rotor body, and which sectionally encloses the polars of the first group and the polars of the second group, such that each of the polars has only one winding head.wherein rotor poles are formed when the windings are energized. The invention further relates to a method for manufacturing a rotor.

[0002] Electric motors are increasingly being used for propulsion in motor vehicles to create alternatives to combustion engines that require fossil fuels. Considerable efforts have already been made to improve the everyday usability of electric drives and to offer users the familiar driving comfort.

[0003] In the development of electric machines, particularly those intended for e-axles or hybrid modules, there is a persistent need to increase their power density and efficiency while simultaneously reducing manufacturing costs. In this context, it is also known to design these electric machines as separately excited synchronous machines (FSMs). A separately excited synchronous machine is a special type of synchronous machine in which the magnetic field in the rotor is generated not by permanent magnets, but by energized coils. These coils are often also referred to as field coils or excitation coils. To energize the coils in the rotating rotor, the current must be supplied via suitable transformers.

[0004] German patent application DE 10 2021 133 566 A1 describes a rotor for an electric machine, consisting of a rotor shaft and a laminated core mounted on it, formed from stacked electrical steel sheets. This laminated core has radially outward-projecting projections. End plates are arranged at the axial ends of the laminated core, which also have radially outward-projecting projections. The rotor windings are wound around these projections and extend axially between the end plate projections. The rotor also includes a cup-shaped end cap on each axial side, which covers the end plates, and a tubular cooling channel that runs axially between the rotor windings and carries a coolant.

[0005] WO 2023 / 232445 A1 describes a rotor for an electrically excited synchronous machine, which has a rotor shaft rotatable about a rotor axis. The rotor comprises a plurality of legs arranged along a circumferential direction of the rotor, with pole slots for receiving electrical conductors of a rotor winding formed between these legs. The legs have pole shoes at their radially outer ends. An essential feature of the described rotor is the formation of at least one cooling path for a cooling medium, which extends from a shaft channel of the rotor shaft via at least one slot supply channel into one of the pole slots and is offset axially by at least one slot section of the pole slot.Within the respective pole groove, the cooling path comprises a collecting channel in the outer groove area for the axial discharge of the cooling medium, as well as at least one radial groove path that runs from the groove base in a radial direction into the collecting channel.

[0006] German patent DE 10 2021 213 810 A1 describes a rotor for an electric machine consisting of a laminated core mounted on a rotor shaft, formed from stacked electrical steel sheets. End plates with radial projections are arranged at the axial ends of the laminated core. These projections serve to receive rotor windings wound around the projections of the end plates. The rotor also includes a cooling system comprising a central cooling channel in the rotor shaft and a peripheral cooling channel in the first end plate, extending outwards from the central cooling channel.

[0007] With rotors of this type for separately excited electric machines, a particular technical challenge arises during the rotor winding process. FSM rotor packages manufactured using a full-cutting technique and featuring small slot openings generally cannot be wound using the highly economical (short cycle time) flyer winding method.

[0008] The flyer winding process is a prior art method for manufacturing coils for the rotors of electrical machines. In this process, a flyer, a rotating tool, is used to wind the wire precisely and evenly around the rotor. The rotor is clamped in a device that controls its rotation during the winding process. The wire is fed from a supply spool and guided through the flyer, which rotates around the component being wound. This method is particularly effective for mass production because it offers an automated and rapid winding method. For example, US 6,419,181 B1 describes a method for winding a core with slots of varying angular spacing and / or different shapes using a flyer winder.This method uses different wing winders for slots with equal spacing, and it includes support links to distribute the wire evenly during winding.

[0009] When winding FSM rotor packages manufactured using full-cutting techniques, a needle winding process is typically employed, which results in a significantly longer cycle time and consequently higher process costs compared to a flyer winding process. Furthermore, this process requires a considerable amount of clearance within the rotor for the needle itself, which negatively impacts the copper fill factor in the rotor winding windows and, consequently, the overall motor efficiency via the rotor winding resistance.

[0010] Winding directly onto a tooth also presents the challenge of requiring significant tension on the wire to limit bulging within the active length. This leads to wire narrowing and increases winding resistance, which in turn negatively impacts the overall motor efficiency.

[0011] Although there are cost-effective and efficient winding methods using linear winding techniques, for example for pre-winding coils, the common, full-cut rotor packages are not suitable for such coils pre-wound by linear winding.

[0012] Furthermore, recycling is more difficult with current rotor designs because the copper can only be separated from the rest of the rotor with great difficulty. Either the entire winding head has to be cut through or the winding unwound backwards, which makes the recycling process complicated and time-consuming.

[0013] Another key technical problem lies in the ohmic losses within the rotor winding. These losses represent a large proportion of the total rotor loss and negatively impact the motor's continuous power output and efficiency. Ohmic losses arise from the electrical resistance of the winding, with a significant portion of the supplied energy being lost as heat. This not only reduces the motor's efficiency but also leads to increased heat generation, which must be dissipated. In many applications, winding cooling represents the bottleneck in terms of the continuous power output of a separately excited synchronous machine (FSM). The heat generated by ohmic losses must be efficiently dissipated to prevent overheating and resulting damage. In practice, it is often difficult to sufficiently minimize the thermal resistance between the conductor sections and the coolant.High thermal resistances mean that heat cannot be effectively dissipated, which increases the temperature of the winding and impairs the continuous performance and lifespan of the machine.

[0014] It is therefore an object of the invention to provide a rotor for a separately excited electric machine and a method for manufacturing a rotor for a separately excited electric machine that avoids or at least reduces the problems known from the prior art. It is also an object of the invention to implement an optimized method for disassembling and recycling a rotor. Furthermore, it is an object of the invention to find solutions that allow a larger copper fill factor in the winding windows of the rotor in order to reduce the resistance of the rotor winding, decrease copper losses, reduce cooling requirements, and thus increase efficiency. At the same time, a means should be provided to minimize the thermal resistances between the conductor sections and the coolant in order to improve cooling performance and increase the continuous power output of the machine.

[0015] This problem is solved by a rotor for a separately excited electric machine, comprising a rotor body formed from a plurality of stacked rotor laminations, which forms several axially extending slots for receiving a winding, and the rotor laminations having a first group of radially extending polars that are monolithically formed with the rotor laminations, wherein the rotor body further comprises a second group of radially extending polars that are positively and / or frictionally and / or materially bonded to the rotor body, and the winding is formed as a ring that is inserted into the slots in a meandering fashion, forming axially projecting winding heads from the rotor body, and sectionally enclosing the polars of the first group and the polars of the second group, so that each of the polars has only one winding head.wherein rotor poles are formed when the windings are energized and wherein the winding is penetrated by a plurality of cooling tubes extending axially through the winding, wherein the cooling tubes are hydraulically coupled to a balancing disc at the winding ends, so that during operation of the rotor, cooling fluid exiting axially from the cooling tubes can exit radially outwards from the balancing disc via a fluid guidance structure formed in the balancing disc.

[0016] This combination of features offers the advantage of significantly improving the cooling of the windings in the rotor of a separately excited electric machine. The integration of the cooling tubes through the winding and their hydraulic coupling to the balancing disc enables efficient heat dissipation from the rotor. The cooling fluid exiting the tubes can be directed radially outwards through the fluid guidance structure of the balancing disc. This reduces the temperature in the rotor, leading to improved performance and service life of the electric machine. Additionally, the cooling results in a more uniform temperature distribution within the rotor, reducing mechanical stresses and potential deformations.

[0017] According to an advantageous embodiment of the invention, the number of polaria in the first group can correspond to the number of polaria in the second group. If the number of polaria in both groups is the same, a symmetrical magnetic field is generated, which can contribute to more uniform torque production and avoid or reduce imbalances that could lead to vibrations or inefficient operation of the electric machine.

[0018] According to a further preferred embodiment of the invention, the polars of the first group and the polars of the second group can also be arranged alternately in the circumferential direction of the rotor body. An alternating arrangement of the two groups of polars can lead to a more uniform torque curve, since the magnetic forces act more evenly on the rotor, which contributes to a reduction in vibrations and an increase in the smooth running of the electric machine.

[0019] Furthermore, according to another advantageous embodiment of the invention, the second group of polars may be formed from a plurality of stacked electrical steel sheets. The stacking of the electrical steel sheets reduces the eddy current losses in the second group of polars.

[0020] In principle, it would be possible that the polars of the second group are formed from a material that differs from the material of the first group and is adapted to the specific function of the second group of polars.

[0021] According to a further particularly preferred embodiment of the invention, the first group of polar elements and the second group of polar elements can be formed from a sheet of identical material thickness and composition. This allows, in particular, the effect that the basic structure and the second group of polar elements are manufactured from an identical sheet, thus enabling correspondingly economical production of the rotor body.

[0022] It can also be advantageous to further develop the invention such that the rotor laminations and the second group of polars are formed from a single sheet, thereby achieving particular cost savings, since on the one hand there is less material waste and on the other hand the complexity in the semi-finished product logistics for manufacturing the rotor body is reduced. The second group of polars can preferably be cut from a sheet or coil, preferably by stamping. Furthermore, it can also be preferred that the second group of polars is manufactured from a grain-oriented sheet.

[0023] It is further preferred that the second group of polars has a tooth width that is smaller than the tooth width of the first group of polars, which can contribute to higher fill levels in the rotor slots. In particular, the second group of polars can have narrower polars if it is stamped from a material with a higher saturation flux density, such as a grain-oriented sheet.

[0024] According to a further preferred embodiment of the invention, the longitudinal extent of the second group of polars can be oriented parallel to the rolling direction of the sheet from which the second group of polars is formed. Since the rotor laminations and the second group of polars can be punched individually, they can be positioned in the rolling direction when punched out of the sheet. This makes it possible to realize further advantages by using grain-oriented sheet, such as lower iron losses in the second group of polars and / or higher saturation flux densities. Due to a higher saturation flux density, the polars of the second group can also be narrower in the circumferential direction than the polars of the first group. Mechanically, this creates an asymmetry between the polars (depending on the current direction, e.g.,All north poles are part of the basic framework, all south poles are in the second group of polars, but not in the magnetic circuit itself. If the polars of the second group are made narrower than those of the first group, this can contribute to a lower weight for the polars of the second group, thereby reducing the centrifugal force caused by their own weight and the associated material stress. Furthermore, narrower polars in the second group can also provide a larger winding window, which in turn optimizes the winding process and the achievable fill factor.

[0025] Finally, the invention can also be advantageously implemented such that, after connecting the polars of the second group to the rotor laminations, a bandage is arranged on the outer shell of the rotor. This allows for increased rotational speed stability of the rotor. The bandage also contributes to the safe operation of the rotor at particularly high speeds. A primary function of such a bandage is therefore to mechanically stabilize the rotor windings. At high speeds, centrifugal forces can exert considerable stress on the windings. The bandage absorbs these forces and prevents the windings from coming loose or slipping. Furthermore, a bandage also protects the rotor windings from external influences such as dust, moisture, or mechanical damage.A bandage is preferably made of a high-strength material, in particular selected from the group of fiber-reinforced composites, glass fiber materials, carbon fiber materials, or special metal alloys. These materials offer high tensile strength while remaining lightweight to avoid negatively impacting rotor dynamics. Preferably, the bandage is designed in the form of a ring or several nested rings that encircle the outer shell of the rotor. An insulating layer can be placed between the rotor and the bandage to provide electrical insulation and compensate for differences in thermal expansion.

[0026] Furthermore, depending on the specific geometry and mechanical utilization (stresses in the sheet metal), it may also be advantageous to switch from a copper winding to an aluminum winding, which can also contribute to the realization of a cost-optimized rotor.

[0027] For the purposes of this patent application, a winding is to be understood as an arrangement of electrically conductive material that is systematically inserted into slots of the rotor in such a way that, when current is applied, a magnetic field is induced within the separately excited electric machine to generate torque. This winding serves to create rotor poles which, through interaction with an external magnetic field, enable the conversion of electrical energy into mechanical rotational motion.

[0028] The winding consists of a deformable electrical conductor, shaped as a ring and laid in a meandering pattern within the slots of the rotor body to form a closed loop. This arrangement creates winding heads that protrude axially from the rotor body, resulting in effective and spatially well-defined field generation. The winding is designed to sectionally enclose the polars of the first and second groups, allowing magnetic poles to form when these groups are energized.

[0029] The winding can be made from various electrically conductive materials. Copper is preferred due to its excellent electrical conductivity and thermal resistance. Furthermore, the winding can be designed in various cross-sectional shapes, such as round, rectangular, or as stranded wire bundles, which allows for optimization of the copper fill factor and thus tailoring it to the specific requirements regarding electrical resistance and heat distribution within the rotor. Preferably, the winding is surrounded by an insulating material to ensure the electrical insulation of the individual turns and to prevent short circuits that could be caused by contact between adjacent turns. In addition to copper, alternative conductor materials such as aluminum or conductive composites could also be used.

[0030] The winding of a ring-shaped coil can be achieved, for example, using established winding techniques such as linear winding or flyer winding. In these processes, the coil is precisely manufactured on an external tool outside the rotor. The calculation of the number of turns for this separately manufactured coil can be based on the total number of turns of the FSM rotor to be produced, divided by the number of pole pairs. This allows for efficient mass production, especially since various winding processes can be carried out simultaneously on a single rotating unit, bringing several copper windings to the intended winding diameter at the same time.Specifically, significant cost savings can be achieved by harmonizing winding production and supply processes, as a wire supplier, for example, can deliver pre-prepared coils directly to the required specifications, considerably reducing the additional effort compared to the conventional winding and rewinding process. Such predefined windings minimize the number of manufacturing steps, as they eliminate the process of rewinding from a standard supplier coil to a diameter specified for the FSM rotor.

[0031] The winding, which follows a similar configuration to that of stator windings with pull-in windings, is then precisely inserted into the rotor body, which is preferably equipped with winding head carriers. During this process, the insertion preferably takes place in an axial direction, with the winding heads located on the side opposite the joining process – for example, the lower ones – still floating freely at this point. Finally, the rotor poles of the second group are attached to the rotor body, so that the winding then meanders around the rotor poles of the first and second groups.

[0032] The winding is preferably pre-wound and then wound on a tool outside the rotor. This is preferably done either by a linear winding process or a flyer winding process. In the linear winding process, the wire is wound linearly onto a tool located outside the future rotor. This method is particularly suitable for applications requiring high precision and uniform winding distribution. In the flyer winding process, the wire is wound onto the tool by a rotating flyer unit. This method offers the advantage of fast and uniform winding, especially with long wire lengths and high production volumes.

[0033] The number of turns in the externally manufactured winding is advantageously calculated by dividing the total number of turns in the separately excited synchronous machine (FSM) rotor to be manufactured by the number of pole pairs. This calculation ensures that the winding is precisely tailored to the rotor's requirements and fulfills the necessary electrical properties.

[0034] Another advantage of external winding on a tool is the ability to run multiple winding operations in parallel. A single rotary unit can unwind several copper coils simultaneously, significantly reducing production time and increasing efficiency. Due to the simplicity of this winding method, there is considerable potential for cost savings. It is possible to order pre-wound coils from the wire supplier, eliminating the need for additional winding processes in the manufacturer's own production. The wire supplier has to wind the wire anyway, and winding it to a defined diameter and regularly cutting it off represents only a minor additional effort. Without this optimization, the supplier would have to wind the wire, and the motor manufacturer would then have to rewind it, incurring additional costs and time.

[0035] The winding preferably includes contacts at its beginning and end. These contacts are preferably made of conductive materials such as copper or a copper alloy, which exhibit high electrical conductivity and low resistance losses. To ensure mechanical stability and durability, the contacts can additionally be provided with a protective coating to prevent corrosion and wear.

[0036] The initial contact is the point where the electric current enters the winding. Technically, this contact consists, for example, of a terminal bolt or clamp that is firmly attached to the beginning of the winding. The initial contact is designed to provide a secure and reliable connection to the external power source. To optimize current transfer, the initial contact can be gold-plated or coated with another conductive layer to minimize contact resistance.

[0037] The end contact is the point where the electric current leaves the winding. Similar to the starting contact, the end contact preferably consists of a terminal bolt or clamp that is firmly connected to the end of the winding. The end contact ensures that the electric current is conducted back to the external power source or to the next winding. Here, too, a conductive coating can be used to reduce contact resistance and ensure efficient current transfer.

[0038] The connection between the contacts and the external power source is typically made via cables or wires that are permanently attached to the terminal bolts or clamps. Several contact designs are possible. One option is screw terminals, which offer a simple and secure way to connect the winding ends to the external power source. They provide a secure connection and can be easily loosened and tightened. Another option is soldered connections, which offer a permanent and reliable electrical connection. Soldered connections are particularly advantageous when a secure and stable connection is required that does not need to be frequently disconnected. Finally, plug connectors can also be used, allowing for quick and easy connection and disconnection of the winding ends.Plug connectors are particularly useful in applications where the winding needs to be frequently assembled and disassembled.

[0039] According to an advantageous embodiment of the invention, a first winding head support rests against a first end face of the rotor body. This support has bearing surfaces aligned with the first group of polars, each supporting a winding head located on the first end face. At the radial ends of these bearing surfaces, an axially extending winding shield is arranged, against which the corresponding winding head is radially supported. The aligned bearing surfaces, which provide axial support for the winding heads, ensure precise alignment of the winding heads. The radial winding shields enhance the protection of the winding heads against mechanical damage and reduce vibrations during operation. This results in improved noise reduction and increased operational reliability.Furthermore, the clear positioning of the winding heads facilitates rotor assembly, which reduces manufacturing costs and can increase production yield.

[0040] According to a further preferred embodiment of the invention, a second winding head support rests against the polars of the second group on a second end face of the rotor body. This support has a bearing surface aligned with the polar, providing a bearing surface for each winding head located on the second end face. At the radial ends of these bearing surfaces, an axially extending winding shield is arranged, against which the corresponding winding head is radially supported. This design simplifies assembly and eliminates the need for complex adjustments. The additional use of the winding shields further stabilizes the winding head connection point, thus improving the mechanical integrity of the rotor during operation.

[0041] Furthermore, according to another advantageous embodiment of the invention, the first winding head support and / or the second winding head supports may be made of a plastic. The use of plastic for manufacturing the winding head supports translates into economic advantages through the reduction of production costs. Plastic offers the possibility of manufacturing by injection molding, which promotes efficient and cost-effective mass production. The reduced weight of the plastic components decreases the overall mass of the rotor, resulting in a lower moment of inertia and thus enabling more dynamic start-up and braking processes. At the same time, the insulating properties of the plastic material allow for improved electrical insulation of the winding heads, which increases the electrical safety of the rotor.

[0042] According to a further particularly preferred embodiment of the invention, the rotor body may have a plurality of circumferentially distributed dovetail grooves extending axially through it, into which a corresponding dovetail contour at the base of a second-group polar element engages, so that a second-group polar element is axially displaceable and radially secured within a dovetail groove. The implementation of dovetail grooves for radially securing the second-group polar elements creates a high-strength, positive-locking connection exhibiting high pull-out strength and vibration resistance. This design also enables non-destructive disassembly of the polar elements, which increases maintenance and repair efficiency and simplifies the recycling process.The use of dovetail joints instead of conventional fasteners such as screws or adhesives speeds up manufacturing and allows for simplified adjustment during assembly. Furthermore, the vibration-resistant anchoring of the polars minimizes the risk of operational disruptions caused by loosening connections.

[0043] Furthermore, the object of the invention can also be achieved by a method for manufacturing a rotor for a separately excited electric machine, comprising the following steps: - Provision of a rotor body formed from a plurality of stacked rotor laminations, which forms several axially extending grooves for receiving a winding, wherein the rotor laminations have a first group of radially extending polars which are monolithically formed with the rotor laminations; - Provision of a second group of polars which can be connected to the rotor body in a form-fitting and / or force-fitting and / or material-fitting manner and wherein the polars of the first group and the polars of the second group can be positioned alternately in the circumferential direction of the rotor body; - Provision of a winding designed as a ring; - Winding the first group of polars by inserting the winding, which is designed as a ring, into the slots from a first axial direction, so that the winding runs meanderingly in the slots, forming winding heads that protrude axially from the rotor body, and partially enclosing the polars of the first group; - Connecting the polars of the second group to the rotor body, so that the winding partially encloses the polars of the second group.

[0044] The manufacturing process according to the invention contributes to reducing process costs by enabling efficient and reproducible assembly of the rotor body and the second group of polars. Winding the first group of polars with a ring winding optimizes the process by, for example, eliminating the need for complex and time-consuming needle winding processes. This reduced cycle time results in increased production speed and, consequently, improved manufacturing efficiency.

[0045] In a further preferred embodiment of the invention, the rotor body may also have a plurality of circumferentially distributed dovetail grooves extending axially through it, and a corresponding dovetail contour is formed at the base of each polar element of the second group, wherein a polar element of the second group is axially inserted into a dovetail groove and is thereby radially secured to the rotor body. The specified use of dovetail grooves in the manufacturing process leads to increased precision and simplified assembly of the rotor. This embodiment emphasizes the modularity of the rotor and simultaneously simplifies the scalability of the production process for different rotor types and sizes. The precise fit and high reliability of the dovetail connections avoid the risk of manufacturing defects that could lead to production rejects.Furthermore, the process supports sustainability by enabling easier separation and recycling of the materials used later, thus improving the technical and economic life cycle of the rotor.

[0046] It can also be advantageous to further develop the invention such that the winding and subsequently the polars of the second group are inserted from a common axial direction, which can improve the ergonomics of both assembly and disassembly. The use and adaptation of automated assembly processes can also be optimized or even enabled in this way. This process optimization results in improved handling and reduces the need for complex assembly systems. Furthermore, the unidirectional assembly creates clear and traceable process sequences, which simplify quality control and process documentation.

[0047] According to a further preferred embodiment of the invention, it may be provided that a) the winding is first placed around the polars of the first group and subsequently the polars of the second group are connected to the rotor body by positive locking and / or force locking and / or material locking or b) the winding is first placed around the polars of the second group and subsequently the polars of the second group are connected to the rotor body by positive locking and / or force locking and / or material locking.

[0048] Finally, the problem of the invention can also be solved by a method for dismantling and recycling a rotor for a separately excited electric machine, comprising the following steps: - Provision of a rotor according to one of claims 1-4; - Separation of the polars of the second group from the rotor laminations of the rotor body; - Removal of the winding from the rotor.

[0049] The process for disassembling and recycling the rotor is thus particularly well-suited to meeting the increasing demands for the environmental compatibility and economic efficiency of electric motors. The systematic and non-destructive separation of the polars from the rotor body, followed by the simple – and also non-destructive – removal of the winding, facilitates the effective recovery of valuable materials such as copper. This approach reduces disassembly times and maximizes the material recycling rate, leading to a reduction in waste and costs in the recycling process. Furthermore, the simplified separation of components improves material separation and sorting, resulting in direct economic benefits for material recovery and contributing to lower disposal costs.

[0050] In this process, for example, the polars of the second group can be pressed out of the rotor body again, in the opposite direction to their insertion. Then, also in the opposite direction to their insertion, the winding is removed from the rotor body. After disassembly, the rotor body, the winding, the second group of polars, and, if applicable, a winding head carrier are separated and can be sent for separate recycling. Cooling tubes

[0051] For the purposes of this patent application, a cooling tube is a tubular component that is passed through the winding of the rotor and serves to supply and remove cooling fluid in order to dissipate heat from the rotor.

[0052] The cooling tube's primary function is to guide cooling fluid through the rotor, thereby efficiently dissipating the generated heat. It extends axially through the rotor winding and is hydraulically coupled to a balancing disc at the winding ends. During rotor operation, the cooling fluid preferentially exits the cooling tube axially and is guided radially outwards via a fluid guidance structure formed in the balancing disc. This effectively dissipates heat from the rotor area. The radially propelled cooling fluid also effectively cools the stator.

[0053] The cooling tube preferably has a cylindrical shape with through openings for the cooling fluid. It is made of a material that can withstand the thermal and mechanical stresses in the rotor. Connections at the ends of the cooling tube allow it to be connected to the mounting points of the balancing disc.

[0054] One possible embodiment is metallic cooling tubes made of metals such as copper, aluminum, or stainless steel. Copper is preferred due to its excellent thermal properties. Alternatively, cooling tubes can be made of high-temperature-resistant plastics such as PEEK (polyetheretherketone) or PTFE (polytetrafluoroethylene), which are lighter and more corrosion-resistant than metallic versions.

[0055] In terms of design, the cooling tube can be a simple tubular shape, which is a cost-effective solution. Another embodiment is a ribbed or finned structure, which increases the surface area of ​​the cooling tube and thus improves heat dissipation. This ribbing or finning can be spiral or longitudinal. Finally, the cooling tube can also be a multi-layered construction, consisting of several layers of different materials that offer an optimized combination of thermal conductivity, mechanical strength, and corrosion resistance. Balancing disc

[0056] For the purposes of this patent application, a balancing disc is a component that is attached to the winding heads of the rotor and serves both for the hydraulic coupling of the cooling tubes and for the distribution of the cooling fluid.

[0057] The balancing disc's primary function is to distribute the cooling fluid exiting the cooling tubes, ensuring uniform cooling of the rotor. It also contributes to rotor balancing and prevents imbalances during operation. The balancing disc is hydraulically connected to the cooling tubes, allowing the cooling fluid to exit preferentially axially and be guided radially outwards by a fluid guide structure integrated into the balancing disc. This results in effective heat dissipation and improved thermal stability of the rotor.

[0058] The balancing disc preferably has a cylindrical shape with a plurality of fluid channels, preferably arranged radially. These channels are positioned to efficiently guide the cooling fluid from the cooling tubes to the fluid outlet openings. The balancing disc can be made of a material that withstands the mechanical and thermal demands of rotor operation. Preferred materials are metals such as aluminum or stainless steel, which offer high strength and thermal conductivity. Alternatively, synthetic or composite materials can be used, which ensure high stability at a low weight.

[0059] One possible embodiment involves the use of straight, radially extending channels, which allow for simple and direct distribution of the cooling fluid. Another embodiment includes a spiral arrangement of the channels, which ensures uniform distribution of the fluid across the entire surface of the balancing disc. In addition, the balancing disc can be provided with a separate cylindrical cover. cover

[0060] For the purposes of this patent application, a cover is a component that surrounds the balancing disc at least partially and serves both to protect the balancing disc and to channel away the cooling fluid in a targeted manner.

[0061] The cover's primary function is to protect the balancing disc and the underlying fluid channels from dirt, damage, and external influences. Furthermore, it facilitates the controlled drainage of the cooling fluid by partially or completely covering the balancing disc's fluid outlet openings and channeling the fluid through designated openings. Additionally, by defining hydraulic pathways, the cover can also prevent hydraulic short circuits in the rotor's fluid system.

[0062] This targeted drainage of the cooling fluid improves the efficiency of the cooling and ensures a uniform heat distribution in the rotor.

[0063] The cover preferably comprises a cylindrical shape with a plurality of through-holes that can be arranged in alignment with the fluid outlet openings of the balancing disc. This configuration enables optimal guidance of the cooling fluid out of the balancing disc.

[0064] The cover can be made of materials that withstand both mechanical stress and thermal influences. Metals such as aluminum or stainless steel are preferred, as they offer high strength and corrosion resistance. Alternatively, heat-resistant plastics or composite materials can be used, combining low weight with high stability.

[0065] One possible embodiment of the cover comprises a one-piece, cylindrical cover that completely encloses the balancing disc and has precisely arranged flow openings. These openings can be of different shapes and sizes to optimally control the fluid flow. Another embodiment comprises a multi-part cover consisting of several segments, allowing for flexible adaptation to different sizes and geometries of the balancing disc. This segmented design can facilitate the installation and maintenance of the cover. Cooling fluid

[0066] For the purposes of this patent application, a cooling fluid is a liquid or gas that is passed through the rotor to dissipate the heat generated and thus regulate the temperature of the rotor.

[0067] The cooling fluid's primary function is to absorb and dissipate the heat generated during rotor operation, preventing overheating of the winding and other components. This targeted cooling ensures the rotor's thermal stability, resulting in improved performance and extended lifespan of the electric machine. The cooling fluid is circulated through cooling tubes and exits at the winding ends, where it is guided radially outwards via a fluid guide structure within the balancing disc.

[0068] Several options are conceivable regarding the embodiment of the cooling fluid. One possible embodiment is the use of water as the cooling fluid, since water has high thermal conductivity and heat capacity. Preferably, the water can be mixed with corrosion inhibitors or antifreeze to increase the service life of the system and to enable its use under different temperature conditions.

[0069] Another embodiment involves the use of special glycol-based coolants, which offer higher temperature resistance and improved lubrication. These coolants are particularly advantageous in applications where extreme temperatures may occur.

[0070] Furthermore, synthetic oils or heat transfer fluids can also be used, which exhibit high thermal stability and good heat transfer efficiency. These fluids are particularly suitable for applications requiring long-lasting and stable cooling.

[0071] For certain applications, the use of gases such as air or inert gases as a cooling fluid can also be considered. These gases offer the advantage of ease of handling and can be used in systems where liquid coolants are unsuitable. Fluid guide structure

[0072] For the purposes of this patent application, a fluid guidance structure is a structural arrangement within the balancing disc that serves to guide and distribute the cooling fluid exiting the cooling tubes in a targeted manner.

[0073] The fluid guide structure's primary function is to efficiently transport the cooling fluid from the cooling tubes to the fluid outlet openings, ensuring a uniform distribution of the fluid. This contributes to effective rotor cooling by dissipating heat evenly. The fluid guide structure ensures that the cooling fluid is preferentially directed radially outwards, thus guaranteeing optimal heat dissipation from the rotor area.

[0074] The fluid flow structure preferably comprises a plurality of channels or lines, which preferably extend radially within the balancing disc. These channels are hydraulically connected to the connection points of the cooling tubes and direct the cooling fluid to the outlet openings. The arrangement and dimensions of the channels are designed to ensure a uniform distribution of the fluid flow and efficient heat transfer. One possible embodiment consists of straight, radially extending channels, which allow for simple and direct flow of the cooling fluid. This embodiment is structurally simple and enables efficient manufacturing. Another preferred embodiment is the use of spiral channels, which ensure a more uniform distribution of the cooling fluid across the entire surface of the balancing disc.This structure can improve cooling performance by maximizing the contact between the cooling fluid and the surfaces to be cooled. Connection points

[0075] For the purposes of this patent application, a connection point is a specially designed connecting device on the balancing disc, which serves to receive and securely fasten the cooling tubes and ensures hydraulic coupling for the flow of the cooling fluid. The primary function of the connection points is to securely and preferably tightly connect the cooling tubes to the balancing disc, so that the cooling fluid is effectively transferred from the cooling tubes into the fluid guide structure of the balancing disc. This enables seamless and loss-free cooling of the rotor. The connection points ensure that the cooling tubes are firmly seated and that the cooling fluid is advantageously guided through the designated channels without leakage.

[0076] The connection points preferably comprise a cylindrical or conical opening in the balancing disc, precisely matched to the dimensions of the cooling tubes. The connection points are preferably designed to enable a positive-locking and / or force-locking connection. They preferably feature seals or O-rings that ensure a hydraulic seal and prevent the cooling fluid from escaping.

[0077] One possible embodiment of the connection points involves the use of simple push-fit connections, where the cooling tubes are inserted directly into the connection points and held in place by friction. This design is advantageous for quick and easy assembly. Another preferred embodiment is the use of screw connections or clamping devices, which provide a tighter and more stable connection. Screw connections can be equipped with additional seals to ensure greater tightness and safety. Clamping devices allow for flexible adjustment to different diameters of the cooling tubes and offer easy maintenance and disassembly. Furthermore, connection points can also be equipped with quick-release couplings, enabling fast and tool-free connection of the cooling tubes.These are particularly advantageous in applications where frequent assembly and disassembly processes are required. cover

[0078] For the purposes of this patent application, a cover is a component that surrounds the balancing disc, at least partially, and supports both the protection of the balancing disc and the targeted drainage of the cooling fluid. The cover's primary function is to protect the balancing disc and the underlying fluid channels from dirt, damage, and external influences. Furthermore, it contributes to the targeted drainage of the cooling fluid by partially or completely covering the fluid outlet openings of the balancing disc and directing the cooling fluid through designated openings. This targeted drainage of the cooling fluid improves cooling efficiency and ensures a uniform heat distribution within the rotor.

[0079] The cover preferably comprises a cylindrical shape with a plurality of through-holes arranged in alignment with the fluid outlet openings of the balancing disc. This configuration ensures optimal flow of the cooling fluid out of the balancing disc. The cover can be made of materials that withstand both mechanical stresses and thermal influences. Metals such as aluminum or stainless steel, which offer high strength and corrosion resistance, are preferred. Alternatively, heat-resistant plastics or composite materials, which combine low weight with high stability, can also be used.

[0080] In one possible embodiment, the cover is designed as a one-piece, cylindrical cover that completely encloses the balancing disc and has precisely arranged flow openings. These openings can be of different shapes and sizes to optimally control the fluid flow. Another embodiment comprises a multi-part cover consisting of several segments, allowing for flexible adaptation to different sizes and geometries of the balancing disc. This segmented design can facilitate the installation and maintenance of the cover. Forming tools

[0081] For the purposes of this patent application, a forming tool is a special tool used for the plastic deformation of the winding to create its final shape and structure. The primary function of the forming tool is to deform the winding so that it conforms to the desired geometric and mechanical properties required for the optimal function of the rotor. The forming tool plastically deforms the winding, thereby precisely adapting its structure and shape.

[0082] The forming tool preferably comprises a robust and precisely manufactured die tailored to the specific requirements of the winding. It is constructed from high-strength materials capable of withstanding the forming forces, such as hardened steel or a special alloy metal. The forming tool may consist of several parts that work together to shape the winding as desired. In particular, the tool's surface has suitable tribological properties to prevent damage to the insulation layers of the individual conductors and, if necessary, to allow relative movement between the tool and the winding.

[0083] Several variations are conceivable regarding the embodiment of the forming tool. One possible embodiment is a forming tool with fixed, non-moving parts designed such that the winding is deformed by simple mechanical pressure. This type of tool is advantageous for simple forming processes where no complex movements are required. Another preferred embodiment is a forming tool with moving parts that enable precise and controlled deformation of the winding. These tools can be hydraulically, pneumatically, or mechanically driven and allow for more precise adjustment of the deformation forces and movements. They are particularly advantageous for complex forming processes where different parts of the winding need to be deformed to varying degrees.

[0084] Additionally, forming tools can be equipped with integrated sensors that monitor and control the deformation in real time. These sensors enable precise control of the forming process and ensure that the winding exhibits exactly the desired properties. This type of tool is particularly suitable for high-precision applications where maximum accuracy and repeatability are required. Spreading tool

[0085] For the purposes of this patent application, a spreading tool is a special tool used for the controlled spreading of the winding in the axially extending section of the winding to form a channel for the insertion of cooling tubes. The primary function of the spreading tool is to temporarily force the winding apart, creating a channel extending axially through the winding. This allows for the easy insertion of cooling tubes into the winding. After the cooling tubes have been inserted, the spreading tool is released, allowing the winding to return to its original shape and firmly enclose the cooling tubes.

[0086] The spreading tool preferably comprises movable arms or spreading elements that can be actuated hydraulically, pneumatically, or mechanically. These elements are designed to spread the winding apart evenly and in a controlled manner without damaging it. The spreading tool is made of robust materials such as hardened steel or special alloy metals that can withstand the forces of spreading.

[0087] One possible embodiment is a mechanical spreading tool in which the arms are actuated manually or by means of screw mechanisms. This design is simple and cost-effective and is advantageously suited for applications where precise, but not automated, control of the spreading action is sufficient. Another preferred embodiment is a hydraulically or pneumatically operated spreading tool, which enables precise and uniform control of the spreading elements. These tools offer the advantage that the spreading action can be powerful and uniform, which is particularly important for larger or tougher windings. Furthermore, these tools can be equipped with sensors that monitor the spreading process in real time and ensure that the winding is not subjected to excessive stress.

[0088] Furthermore, spreading tools can also be modular in design, allowing them to be adapted to different sizes and shapes of windings. This modular design enables flexible application in various manufacturing processes and increases the tool's versatility. Radial press tools

[0089] For the purposes of this patent application, a radial pressing tool is a special tool used for the plastic deformation of the winding in a radial direction to create its shape and structure for optimal use in the rotor. The primary function of the radial pressing tool is to compress the winding radially to densify it and improve its mechanical and electrical properties. This radial compression increases the density of the winding, resulting in better heat dissipation and increased stability. Simultaneously, it improves the geometric accuracy of the winding, thereby increasing the efficiency and reliability of the rotor.

[0090] The radial pressing tool preferably comprises several pressure elements evenly spaced around the winding and acting radially upon it. These pressure elements can be actuated hydraulically, pneumatically, or mechanically to ensure uniform and controlled crimping. The tool is made of high-strength materials such as hardened steel or special alloy metals that withstand the crimping forces and ensure a long tool life.

[0091] One possible embodiment is a hydraulically operated radial pressing tool, which enables precise and powerful crimping. These tools offer the advantage that the pressing force can be precisely controlled, ensuring uniform deformation of the winding. Hydraulic radial pressing tools are particularly advantageous for applications requiring high pressing forces. Another preferred embodiment is a pneumatically operated radial pressing tool driven by compressed air. These tools are lighter and more flexible than hydraulic versions and are advantageously suited for applications requiring quick and easy adjustment of the pressing elements. Pneumatic tools also offer the advantage of a fast response time and easy integration into automated manufacturing processes.Furthermore, mechanical radial press tools can be used, in which the pressing elements are actuated manually or by mechanical drives. These tools are simple and robust and are advantageously suited for applications where high pressing forces are not required and manual control is sufficient. Axial press tools

[0092] For the purposes of this patent application, an axial pressing tool is a special tool used for the plastic deformation of the winding in the axial direction in order to create its shape and structure for optimal use in the rotor. The primary function of the axial pressing tool is to compress the winding in the axial direction to densify it and improve its mechanical and electrical properties. die

[0093] For the purposes of this patent application, a die is a forming tool used to plastically deform a winding into a predetermined geometric shape by acting as a die in a forming process. The die's primary function is to bring the winding into the desired final shape through plastic deformation. It acts as a forming element, forcing the winding into a specific shape, thereby optimizing the winding's mechanical and electrical properties. The use of the die ensures high precision and repeatability in the forming process, leading to consistent and high-quality results.

[0094] The die assembly preferably comprises a hollow or negative mold that precisely corresponds to the desired final shape of the winding. It is made of high-strength materials such as hardened steel or special alloy metals that can withstand the high forces and stresses encountered during the forming process. The die can be manufactured from a single piece or consist of several parts that work together to create the desired shape.

[0095] Several die designs are conceivable. One possible design is a one-piece die with a fixed shape, suitable for simple, less complex forming processes. This design offers the advantage of high stability and durability, as there are no moving parts subject to wear. Another preferred design is a multi-piece die in which several segments or inserts interact to create the final shape. This modular design allows for greater flexibility in adapting the die to different shapes and sizes of windings. Furthermore, a multi-piece die is easier to maintain and repair, as individual parts can be replaced if worn or damaged. In addition, dies can also be equipped with integrated cooling channels or heating systems to optimize the forming process.These additional functions enable precise control of the temperature during deformation, which positively influences the material properties of the winding and makes the forming process more efficient. Swivel tool

[0096] For the purposes of this patent application, a pivoting tool is a special tool used for the targeted plastic deformation of the winding by pivoting movements, in order to deform specific parts of the winding out of their original plane. The pivoting tool has the primary function of moving the winding heads into a predetermined position by pivoting these parts of the winding out of their plane. This movement brings the winding into the desired geometric shape, which improves the mechanical and electrical properties of the winding and optimizes it for use in the rotor. The pivoting movement enables precise and controlled deformation of the winding heads, ensuring the production of a uniform and structurally stable winding.

[0097] The swivel tool assembly preferably comprises a frame or holder that keeps the tool in the correct position, as well as one or more swivel arms that move the winding heads. These swivel arms can be actuated hydraulically, pneumatically, or mechanically to enable precise and controlled movement. The swivel tool is made of high-strength materials such as hardened steel or special alloy metals that withstand the forces and stresses during the swiveling process. Advantageous embodiments of the invention

[0098] According to an advantageous embodiment of the invention, the cooling tubes can protrude axially from the winding heads and engage in corresponding connection points of the balancing disc. This enables a stable and precise connection of the cooling tubes to the balancing disc, which improves fluid flow and prevents leakage.

[0099] According to a further preferred embodiment of the invention, the fluid guide structure can also be provided with a plurality of radially extending fluid channels, wherein the fluid guide channels are hydraulically connected to the connection points and each has a radially extending fluid outlet opening. The fluid guide structure with a plurality of radially extending fluid channels offers the advantage of efficient distribution of the cooling fluid from the connection points to the radially extending fluid outlet openings. This ensures uniform cooling of the winding and the rotor laminations, which increases the thermal stability and performance of the rotor. Furthermore, this structure enables targeted coolant control and contributes to the reduction of hotspots in the rotor.

[0100] Furthermore, according to another advantageous embodiment of the invention, the balancing disc can be at least partially enclosed by a cylindrical cover with a plurality of through-openings, wherein the cover is configured such that a plurality of the fluid outlet openings of the balancing disc are aligned with the through-openings of the cover and a plurality of the fluid outlet openings are at least partially, preferably completely, covered by the cover. The arrangement of the balancing disc within a cylindrical cover with through-openings offers several advantages. On the one hand, the cover protects the balancing disc and the underlying fluid channels from dirt and damage. On the other hand, the alignment of the fluid outlet openings with the through-openings ensures efficient drainage of the cooling fluid from the rotor.This improves the overall cooling performance and contributes to the machine's longevity and reliability.

[0101] The advantage of this design lies in the fact that it enables a cost-effective and easy-to-install connection of the cooling tubes, which can also be adapted as the same component for different sizes. Furthermore, the risk of insulation damage during assembly is low, as the tubes protrude above the winding.

[0102] According to a further particularly preferred embodiment of the invention, methods for manufacturing a rotor for a separately excited electric machine may comprise the following steps: - Provision of a winding designed as a ring; - Shaping the winding using forming tools, wherein the forming tools plastically deform the winding alternately radially inwards and radially outwards distributed over the circumference; - Inserting an axially extending winding section of the manufactured rotor into a spreading tool, which in a first operating position causes the winding to spread and in a second operating position causes the winding to release; - Spreading the winding in the area of ​​the axially extending winding section, so that a channel extending axially through the winding section is formed; - Inserting a cooling tube into the channel; - Releasing the expansion of the winding using the expanding tool;

[0103] This method for manufacturing a rotor for a separately excited electric machine offers the advantage of precise and controlled winding shaping. Forming with special tools achieves uniform plastic deformation of the winding, which is crucial for the subsequent integration of the cooling tubes and the formation of the winding ends. This results in high manufacturing quality and reduces the likelihood of production defects.

[0104] The present invention relates to the manufacture of a rotor for a separately excited electric machine, which is particularly aimed at reducing the ohmic losses in the rotor winding and improving the cooling performance. The solution according to the invention is based on several innovative concepts and methods that are combined to increase the efficiency and continuous power output of the rotor.

[0105] A preferred feature of the invention in this context is the compression of the winding before it is inserted into the rotor core. This compression is carried out using special tool components that bring the winding into a compact and dense shape. The compression increases the copper fill factor in the winding windows, resulting in lower electrical resistance of the winding. This reduces ohmic losses and improves the efficiency of the rotor. Before the compression process begins, cooling tubes are inserted into the winding. These cooling tubes serve to effectively dissipate heat during rotor operation. To ensure that the cooling tubes are not undesirably deformed during the compression process, tool components (e.g., pins) can advantageously be inserted through the cooling tubes.These pins stabilize the tubes and prevent deformation, ensuring the cooling channels remain intact and their function is not impaired. This significantly improves the rotor's cooling performance by minimizing thermal resistance between the conductor sections and the coolant.

[0106] Another important aspect of the invention is the preferred integration of the coolant routing and distribution function into the rotor's balancing discs. The balancing discs are equipped with a fluid guide structure that selectively distributes the coolant exiting the cooling tubes and directs it radially outwards. This fluid guide structure ensures that the coolant is distributed efficiently and uniformly, which improves heat dissipation and increases the rotor's thermal stability. Integrating this function into the balancing discs helps to reduce the rotor's complexity and maximize cooling efficiency.

[0107] The rotor winding is preferably based on a classic round wire wave winding concept, supplemented by additional steps for shaping the cross-section of the winding strand. These additional steps include the plastic deformation of the round wire into an optimized cross-sectional shape, which further increases the copper fill factor and reduces ohmic losses. The combination of this shaping with the compression of the winding before insertion into the core ensures a particularly dense and efficient winding structure.

[0108] Furthermore, the invention can also be further developed such that, after releasing the winding's expansion, the winding is plastically deformed in the axial direction to form axially alternating winding heads. After releasing the winding's expansion, plastic deformation in the axial direction occurs to form the winding heads. This method offers the advantage that the winding heads are formed precisely and consistently, which improves the mechanical integrity and electrical properties of the winding. The axial deformation also ensures a compact and space-saving rotor design.

[0109] In a further preferred embodiment of the invention, it can also be provided that, after deformation in the axial direction, at least partial plastic deformation of the winding is carried out in the radial direction using radial pressing tools. This additional plastic deformation of the winding in the radial direction using radial pressing tools enables further optimization of the winding structure. This improves the density and strength of the winding, resulting in higher mechanical stability and better electrical conductivity. This deformation contributes to the overall performance and efficiency of the electric machine.

[0110] It can also be advantageous to further develop the invention such that, after deformation in the axial direction or after deformation in the radial direction, at least partial plastic deformation of the winding in the axial direction is carried out using axial pressing tools. The partial plastic deformation of the winding in the axial direction after initial deformation allows for a finer adjustment of the winding geometry. The use of axial pressing tools further compacts and shapes the winding, which improves heat dissipation and mechanical strength. This additional processing step increases the precision and quality of the finished rotor. According to a further preferred embodiment of the

[0111] The invention may involve axial deformation by means of a drawing process in a die. Axial deformation by means of a drawing process in a die offers the advantage of controlled and uniform shaping of the winding. This process enables high precision and repeatability in manufacturing, leading to improved production consistency and reduced manufacturing costs. The die ensures a defined shape of the winding heads, which improves winding efficiency and the overall performance of the machine.

[0112] Finally, the invention can also be advantageously implemented such that the axial deformation is carried out using pivoting tools that engage the future winding heads on an axial side of the rotor and pivot them out of the plane of the winding. Deformation of the winding in the axial direction using pivoting tools offers an innovative method for forming the winding heads. This technique enables precise and controlled deformation, resulting in a uniform distribution of the winding heads. This contributes to the mechanical stability and electrical efficiency of the winding. The targeted pivoting optimally shapes the winding into its final form, reducing the overall costs and effort involved in rotor manufacturing.

[0113] The advantage that results from this is, in particular, that it allows for a winding shape that is as gentle as possible on the winding insulation.

[0114] The invention will now be explained in more detail with reference to figures, without limiting the general concept of the invention.

[0115] It shows: Fig. 1. A separately excited electrical machine in a schematic axial section view, Fig. 2 the second group of polars in an assembled and an unassembled state, each in a cross-sectional view, Fig. 3. A rotor in its first assembly state in a perspective view, Fig. 4. A rotor in a second assembly state in a perspective view, Fig. 5. A rotor in a third assembly state in a perspective view, Fig. 6 a rotor in a third assembly state in a cross-sectional view, Fig. 7 a freestanding first winding head support in a perspective view, Fig. 8 a winding in a ring-shaped and a meander-shaped assembly state, each in a perspective view, Fig. 9 a winding in a ring-shaped and a first deformation state in a schematic representation, Fig. 10 a winding section in a spreading tool in a first unspread state, a spread state and with an inserted cooling tube, each in a schematic representation, Fig. 11 a winding with inserted cooling tube in a die in a first assembly state, Fig. 12 of them Fig. 11 known windings in the forming process on the die using radial pressing tools, Fig. 13 who are from the Fig. 11 known windings in the forming process on the die using axial press tools, Fig. 14 a reshaping of the winding using swivel tools, Fig. 15 a rotor with an inserted winding from which the cooling tubes protrude in a perspective view, Fig. 16 the from the Fig. 15 known rotors with a balancing disc and cover on each end face in a perspective view, Fig. 17 of them Fig. 16 known balancing discs in a top view, in a sectional view and in a side view, Fig. 18 who are from the Fig. 16 known covers in a perspective view.

[0116] The Fig. Figure 1 shows a current-carrying rotor 1, which is rotatably mounted in a hollow cylindrical stator 41 of the separately excited electric machine 2. The hatching clearly shows that the rotor body 4 of the rotor is formed from a plurality of stacked rotor laminations 3.

[0117] In the Fig. Figures 4-7 clearly show that the rotor body 4 has several circumferentially distributed and axially extending grooves 5 for receiving the winding 6. When the winding 6 is energized, the rotor poles 7 are formed, which are positioned radially between each pair of the grooves 5. These are labeled N and S in the figures for magnetic north and south poles. The rotor laminations 3 have a first group of radially extending polars 9, which are monolithically formed with the rotor laminations 3. The rotor laminations 3 also have the annular yoke.

[0118] The rotor laminations 3 also have a second group of radially extending polars 10, which are positively connected to the rotor laminations 3 via the yoke. Fig. It is also clearly evident from Figures 4-7 that the polar elements 9 of the first group and the polar elements 10 of the second group are arranged alternately in the circumferential direction of the rotor body 4. In the illustrated embodiment, the number of polar elements 9 of the first group corresponds to the number of polar elements 10 of the second group.

[0119] The second group of Polarmen 10 is also formed from a plurality of stacked electrical steel sheets, wherein the first group of Polarmen 9 and the second group of Polarmen 10 are formed from a sheet with identical material thickness and material composition.

[0120] In the exemplary embodiments, the polar elements 10 of the second group are joined by means of a positive-locking connection, which has a dovetail groove 44 in the rotor sheet. The dovetail contour 46, which is formed at the radially inner end of the polar elements 10 of the second group, can engage positively in this groove. The positive lock can be achieved by axially inserting the second group of polar elements 10 into the respective dovetail grooves 44, which is particularly well illustrated by the Fig. 2 can be seen. The second group of polar men 10 has a tooth width X that can be smaller than the tooth width Y of the first group of polar men 9, which can create additional space for winding material in the slots 5.

[0121] As from the Fig. As can be seen in Figure 3, the rotor laminations 3 and the second group of polars 10 can be formed from a common sheet. It can also be advantageous if the longitudinal extent of the second group of polars 10 is oriented parallel to the rolling direction of the sheet from which the second group of polars 10 is formed.

[0122] The winding 6 of the rotor 1 is designed as a ring, which is inserted into the slots 5 in a meandering pattern, forming winding heads 20a, 20b projecting axially from the rotor body 4. It sectionally encloses the poles 9 of the first group and the poles 10 of the second group, so that when the windings 6 are energized, rotor poles 7 are formed. The ring-shaped design and the meandering form of the winding can be particularly well illustrated by the Fig. 9. From the overall view of the Fig. Figures 6-7 show that each pole has a winding head 20a,20b on only one side. This distinguishes this winding 6 from a concentrated winding of every second tooth, where every second tooth has no winding head at all, but every second tooth has a winding head on both end faces.

[0123] A first winding head carrier 22 rests against the first end face 21 of the rotor body 4. This carrier has support surfaces 23 aligned with the first group of polars 9, each for a winding head 20a of the winding 6 located on the first end face 21. At the radial ends 24 of the support surfaces 23, an axially extending winding shield 25 is arranged, against which the corresponding winding head 20a is radially supported. As can be seen from the Fig. As can be clearly seen in Figure 8, the first winding head support 22 has a cross-like design with a central circular opening, the bearing surfaces 23 being designed so that they lie fully on the front surface of the first group of polars 9, which is particularly evident from the Fig. 4 can be seen. In this case, the number of contact surfaces 23 corresponds to the number of polars 9 of the first group.

[0124] On the second end face 26 of the rotor body 4, a second winding head support 27 is located on each of the polars 10 of the second group. This support has a bearing surface 28 aligned with the polar 10 for each winding head 20b of the winding 6 located on the second end face 26. At the radial ends 29 of the bearing surfaces 28, an axially extending winding shield is arranged, against which the corresponding winding head 20b is radially supported. A second winding head support 27 is located in the Fig. Figure 11 shows that each of the winding head supports 27 must be mounted on one of the polars 10 of the second group, whereas the first winding head support 22 covers all polars 9 of the second group. In the illustrated embodiment, the first winding head support 22 and the second winding head supports 27 are molded from a plastic.

[0125] How to also get good results from the overall view of the Fig. 2 with the Fig. As can be seen from 4-7, the rotor body 4 has a plurality of dovetail grooves 44 distributed circumferentially and extending axially through it, into which a corresponding dovetail contour 46 engages at the base 51 of a polar element 10 of the second group, so that a polar element 10 of the second group is axially displaceable and radially secured in a dovetail groove 44.

[0126] With this configuration, the rotor 1 can be manufactured as follows. First, a rotor body 4, formed from a plurality of stacked rotor laminations 3, is provided. This rotor body has several axially extending grooves 5 for receiving a winding 6. The rotor laminations 3 have a first group of radially extending polars 9, which are monolithically formed with the rotor laminations 3. Furthermore, a second group of polars 10 is provided, which can be connected to the rotor body 4 by positive locking, frictional locking, and / or material bonding. The polars 9 of the first group and the polars 10 of the second group can be positioned alternately around the circumference of the rotor body 4. Finally, a winding 6, configured as a ring, is provided.

[0127] The first winding head carrier 22 is then mounted onto the rotor body 4, so that the one in the Fig. The assembly state shown in Figure 4 results in the following. The first group of polars 9 is then wound by inserting the ring-shaped winding 6 into the slots 5 from a first axial direction, so that the winding 6 runs meanderingly in the slots 5, forming winding heads 20 that project axially from the rotor body 4, and sectionally encloses the polars 9 of the first group. This assembly state is shown in the Fig. 5 shown.

[0128] The one in Fig. The assembly state shown in Figure 5 is thus achieved by first placing the winding 6 around the poles 9 of the first group and subsequently connecting the poles 10 of the second group to the rotor body (4) in a form-fit and / or force-fit and / or material-fit manner, as shown in the following Fig. 6 can be seen. Although not shown in the figures, the winding 6 can alternatively be first placed around the polars 10 of the second group, and subsequently the polars 10 of the second group can be connected to the rotor body 4 by a positive fit, force fit, and / or material bond. The individual polars 10 of the second group are positioned using tools, and then the winding 6 is placed around these polars 10. Only as the last part does the rotor body 4 come into play, which is then pushed into the pre-positioned polars 10, including the winding 6 located therein.

[0129] Now the polars 10 of the second group are connected to the rotor body 4, so that the winding 6 partially encloses the polars 10 of the second group, which in the Fig. Figure 6 shows that the rotor body 4 has a plurality of dovetail grooves 44 distributed circumferentially and extending axially through it, and a corresponding dovetail contour 46 is formed at the base 51 of each pole 10 of the second group, wherein a pole 10 of the second group is axially inserted into a dovetail groove 44 and is thereby radially secured to the rotor body 4. The winding 6 and subsequently the poles 10 of the second group are inserted from a common axial direction.

[0130] Based on the Fig. 10. The procedure for dismantling and recycling the rotor 1 for a separately excited electric machine 2 can be briefly explained. First, the polars 10 of the second group are separated from the rotor laminations 3 of the rotor body 4 from the Fig. 6-7 known, assembled rotor 1. This is achieved by axially pushing the polars 10 of the second group out of the rotor body 4 in the opposite direction to their original assembly direction (indicated by the upward-pointing arrow). The winding 6 can then be removed from the rotor 1. Thus, the components of the rotor 1 can be disassembled simply and non-destructively, leading to simple and effective material recycling. With the rotor body 4 stationary, the polars 10 of the second group are pressed out of the assembly towards the end face without the winding head. This allows them to be pressed out without necessarily damaging or cutting the winding 6.

[0131] The Fig. Figure 15 shows that the winding 6 is designed as a ring which is inserted into the slots 5 in a meandering shape, forming winding heads 20a, 20b projecting axially from the rotor body 4, and which sectionally encloses the polars 9 of the first group and the polars 10 of the second group, so that each of the polars 9, 10 has only one winding head 20a, 20b, wherein the winding 6 is penetrated by a plurality of cooling tubes 11 extending axially through the winding 6, wherein the cooling tubes 11 are hydraulically coupled to a balancing disk 12 at the winding heads 20a, 20b, so that during operation of the rotor 1, cooling fluid 13 exiting axially from the cooling tubes 11 can exit radially outwards from the balancing disk 12 via a fluid guide structure 14 formed in the balancing disk 12, which in the Fig. 16 can be seen.

[0132] From the overall view of Fig. Figures 15-18 further show that the cooling tubes 11 protrude axially from the winding heads 20a, 20b and engage in corresponding connection points 15 of the balancing disc 12. The fluid guide structure 14 has a plurality of radially extending fluid channels 16, wherein the fluid guide channels 16 are hydraulically connected to the connection points 15 and each has a radially directed fluid outlet opening 17.

[0133] In the illustrated embodiment, the balancing disc 12 is at least partially enclosed by a cylindrical cover 18 with a plurality of through-openings 19. The cover 18 is configured such that a plurality of the fluid outlet openings 17 of the balancing disc 12 are aligned with the through-openings 19 of the cover 18, and a plurality of the fluid outlet openings 17 are completely covered by the cover 18 to prevent a hydraulic short circuit in the rotor 1. For this purpose, some of the fluid outlet openings 17 are covered by closures 40. In the assembled state, the cover 18 assumes the function of the closures 40.

[0134] Based on the Fig. In sections 9-14, possible methods for manufacturing a rotor 1 for a separately excited electric machine 2 can be explained in more detail. As in the Fig. As shown in Figure 9, a winding 6 shaped as a ring is first provided (Figure a). Then, as shown in Figure b, the winding 6 is shaped using forming tools 30, whereby the forming tools 30 plastically deform the winding 6 alternately radially inwards and radially outwards across its circumference, so that a star-shaped contour of the winding 6 is created. This produces a first group of winding heads 20a at the radially outer ends and a second group of winding heads 20b at the radially inner ends.

[0135] The star-shaped plastically deformed winding 6 is then inserted, with its axially extending winding section 31 in the manufactured rotor 1, into a spreading tool 32, which in a first operating position causes the winding 6 to spread and in a second operating position causes the spreading of the winding 6 to release, which in the Fig. Figure 10 shows that each of the winding sections 31 can be inserted into a corresponding spreading tool 32, but this has not been shown in the figures for the sake of clarity.

[0136] How to use the Fig. the Fig. As can be seen in Figure 10, the winding 6 is then spread in the area of ​​the axially extending winding section 31, so that a channel 33 extending axially through the winding section 31 is formed. A cooling tube 11 is then inserted into the channel 33, as shown in Figure e of the Fig. 10 can be seen. Finally, the spreading of the winding 6 is released by the spreading tool 32, so that the cooling tube 11 is then fixed in the winding section 31 of the winding 6.

[0137] After releasing the expansion of the winding 6, the winding 6 is plastically deformed in the axial direction so that axially alternating winding heads 20a, 20b are formed around its circumference, as is the case, for example, in the Fig. 8 can be seen.

[0138] The deformation in the axial direction can, for example, be carried out by means of a drawing process in a die 36, which is described in the Fig. Figure 11 shows that the die 36 is cylindrical and has a plurality of axial grooves 39 distributed equidistantly around its circumference, into which the winding sections 31 are drawn or inserted. The axial grooves 39 have a trapezoidal cross-sectional contour. The winding heads 20a are each held by the winding head receptacles 38.

[0139] After deformation in the axial direction, at least partial plastic deformation of the winding 6 is then carried out in the radial direction using radial pressing tools 34, which in the Fig. Figure 12 shows that the winding 6 in the winding section 31 is inserted into a corresponding axial groove 39 and then pressed into the axial groove using a suitable radial pressing tool 34, as can be clearly seen in the lower figure. Fig. 12 can be seen. Here, the cooling tubes 11 ensure that a flow cross-section for the cooling fluid 13 is maintained even during and after the radial crimping of the winding 6. The radial crimping plastically deforms the individual conductor cross-sections of the winding 6 in the area of ​​the winding section 31, so that preferably no air gaps – apart from the cooling tubes – remain between the individual conductor cross-sections after crimping.

[0140] After deformation in the axial direction or after deformation in the radial direction, it is also possible to carry out at least partial plastic deformation of the winding 6 in the axial direction using axial pressing tools 35, which is described in the Fig. Figure 13 is sketched. Here too, the individual conductor cross-sections of the winding 6 can be crimped in the areas of the winding heads 20.

[0141] The deformation of winding 6 from Fig. 9 in the axial direction can alternatively be achieved using pivoting tools 37 instead of the die 36. These tools engage the future winding heads 20a, 20b on an axial side of the rotor and pivot them out of the plane of the winding 6. This is described in the Fig. 14 shown.

[0142] The invention is not limited to the embodiments illustrated in the figures. The foregoing description is therefore not to be considered limiting, but rather explanatory. The following claims are to be understood as meaning that a named feature is present in at least one embodiment of the invention. This does not preclude the presence of further features. Insofar as the claims and the foregoing description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing any hierarchy. Reference symbol list 1 Rotor 2 electric machine 3 rotor laminations 4 rotor bodies 5 grooves 6 windings 7 rotor poles 9 Polar Seas 10 Polar Seas 11 cooling tubes 12 Balancing disc 13 Cooling fluid 14 Fluid flow structure 15 connection points 16 fluid channels 17 Fluid outlet opening 18 Cover 19 passage openings 20 winding heads 21 Front 22 winding head carriers 23 Contact area 24 ends 25 Wrapping shield 26 Front 27 winding head carriers 28 contact surfaces 29 ends 30 forming tools 31 Winding section 32 Spreader tool Channel 33 34 radial press tools 35 axial press tools 36 die 37 swivel tools 38 Winding head attachment 39 axial grooves 40 closure 41 Stator 44 dovetail grooves 46 Dovetail contour 51 feet

Claims

Rotor (1) for a separately excited electric machine (2), comprising a rotor body (4) formed from a plurality of stacked rotor laminations (3), which forms several axially extending slots (5) for receiving a winding (6), and the rotor laminations (3) having a first group of radially extending polars (9) which are monolithically formed with the rotor laminations (3), wherein the rotor body (4) further comprises a second group of radially extending polars (10) which are positively and / or frictionally and / or materially bonded to the rotor body (4), and the winding (6) is formed as a ring which is inserted into the slots (5) in a meandering manner, forming axially projecting winding heads (20a, 20b) from the rotor body (4), and the polars (9) of the first group and the polars (10) of the second group are sectionally surrounds, so that each of the polar seas (9,10) each has only one winding head (20a, 20b), wherein rotor poles (7) are formed when the windings (6) are energized, wherein the winding (6) is penetrated by a plurality of cooling tubes (11) extending axially through the winding (6), wherein the cooling tubes (11) are hydraulically coupled to a balancing disk (12) at the winding heads (20a, 20b), so that during operation of the rotor (1) cooling fluid (13) exiting axially from the cooling tubes (11) can exit radially outwards from the balancing disk (12) via a fluid guide structure (14) formed in the balancing disk (12). Rotor (1) according to claim 1, wherein the cooling tubes (11) extend axially out of the winding heads (20a, 20b) and engage in corresponding connection points (15) of the balancing disc (12). Rotor (1) according to claim 1 or 2, wherein the fluid guide structure (14) has a plurality of radially extending fluid channels (16), wherein the fluid guide channels (16) are hydraulically connected to the connection points (15) and each has a radially extending fluid outlet opening (17). Rotor (1) according to one of the preceding claims, wherein the balancing disk (12) is at least partially enclosed by a cylindrical cover (18) with a plurality of through-holes (19), wherein the cover (18) is configured such that a plurality of the fluid outlet openings (17) of the balancing disk (12) are aligned with the through-holes (19) of the cover (18) and a plurality of the fluid outlet openings (17) are at least partially, preferably completely, covered by the cover (18). Methods for manufacturing a rotor (1) for a separately excited electric machine (2) comprise the following steps: - providing a winding (6) shaped as a ring; - shaping the winding (6) using forming tools (30), wherein the forming tools (30) plastically deform the winding (6) alternately radially inwards and radially outwards distributed over its circumference; - inserting an axially extending winding section (31) of the winding (6) in the manufactured rotor (1) into a spreading tool (32), which in a first operating position causes the winding (6) to be spread and in a second operating position causes the winding (6) to be released; - spreading the winding (6) in the region of the axially extending winding section (31) so that a channel (33) extending axially through the winding section (31) is formed; - inserting a cooling tube (11) into the channel (33); - releasing the Spreading of the winding (6) by the spreading tool (32). Method according to claim 5, wherein after releasing the spreading of the winding (6) the winding (6) is plastically deformed in the axial direction so that axially alternating winding heads (20a,20b) are formed around the circumference. Method according to claim 6, wherein after deformation in the axial direction, at least partial plastic deformation of the winding (6) is carried out in the radial direction by means of radial pressing tools (34). Method according to claim 5 or 6, wherein after deformation in the axial direction or after deformation in the radial direction, at least partial plastic deformation of the winding (6) in the axial direction is carried out by means of axial pressing tools (35). Method according to claim 6, wherein the deformation in the axial direction is carried out by means of a drawing process in a die (36). Method according to claim 6, wherein the deformation in axial direction is carried out by means of pivoting tools (37) which engage the subsequent winding heads (20a, 20b) of an axial side of the rotor and pivot them out of the plane of the winding (6).

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