Contactless energy transmission device and method for producing a contactless energy transmission device

Abstract

The invention relates to a contactless energy transmission device (1) for a rotor (2) of an electric machine (3), in particular a separately excited synchronous machine within the powertrain of a motor vehicle, comprising an inductive transformer (4), which has a primary winding (5) that can be supplied with a current and a secondary winding (6) situated coaxially and at a distance thereto, said secondary winding being electrically conductively coupleable to a winding (7) of the rotor (2). The primary winding (5) and the secondary winding (6) are each designed as a foil winding; the primary winding (5) has a first annular primary insulation element (9) at a first end face (8) of the energy transmission device (1) and a second annular primary insulation element (11) at a second end face (10) of the energy transmission device (1), said primary insulation elements being configured such that the primary winding (5) is insulated from primary flux-conducting elements (12) by means of the primary insulation elements (9, 11); and the secondary winding (6) has a first annular secondary insulation element (13) at the first end face (8) of the energy transmission device (1) and a second annular secondary insulation element (14) at the second end face (10) of the energy transmission device (1), said secondary insulation elements being configured such that the secondary winding (6) is insulated from secondary flux-conducting elements (15) by means of the secondary insulation elements (13, 14).

Description

[0001] Contactless energy transfer device and method for manufacturing a contactless energy transfer device

[0002] The present invention relates to a contactless energy transmission device for a rotor of an electric machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising an inductive transformer having a currentable primary winding and a spaced-apart and coaxially arranged secondary winding, which in turn can be electrically coupled to a winding of the rotor, wherein the primary winding and the secondary winding are each designed as foil windings. The invention further relates to a method for manufacturing a contactless energy transmission device.

[0003] 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.

[0004] In addition to purely electric powertrains, hybrid powertrains are also known. Such powertrains in hybrid vehicles typically comprise a combination of an internal combustion engine and an electric motor, enabling – for example, in urban areas – purely electric operation while simultaneously providing sufficient range and availability, especially on long-distance journeys. Furthermore, it is possible to use both the internal combustion engine and the electric motor simultaneously in certain operating situations.

[0005] In the development of electric machines intended for e-axles or hybrid modules, there is a continuing need to increase their power density and efficiency while simultaneously reducing manufacturing costs, as the vehicle's cost and weight are largely determined by the battery size. In this context, it is also known to design the electric machines as separately excited synchronous machines (FSMs). Here, electrical power must be transferred to the rotor of a separately excited synchronous machine to excite the rotor windings. For traction machines, a contact-based transformer is typically used for this purpose. When these windings are energized, a magnetic field is generated, which, in combination with the stator's magnetic field, produces a torque. The strength of the rotor field can be adjusted by varying the current applied.This allows the machine's behavior to be continuously adapted to the respective driving situation in an efficiency-optimized manner.

[0006] The disadvantages of such a contact-based transmitter include mechanical and electrical losses in the contact between stationary and rotating components. Further disadvantages are the wear of the rubbing components and the associated contamination from abrasion, as well as the comparatively large installation space requirement.

[0007] As an alternative to such contact-based transformers, contactless inductive transformers are also known. An inductive transformer is typically a rotationally symmetrical transformer with an air gap, consisting of a primary and a secondary winding. An inductive transformer usually also has a core, for example made of ferrite. Such a core can be made of one or more parts.

[0008] For example, all parts of the core can be attached to the stationary side of an electric machine, with the secondary winding rotating within the core. Alternatively, core parts can be attached to the rotating part of the machine. In this case, the primary and secondary core parts are separated by an air gap. This gap must be large enough to ensure that the core parts do not touch, taking all tolerances and operating conditions into account. The rotating transformer parts are often fitted with a bandage or integrated into another component to support them at higher speeds. An example of such a design can be found in DE 10 2017 214 776 A1 or in DE201210201826 A1.The object of the invention is to avoid the disadvantages known from the prior art and to provide an optimized contactless energy transfer device for a rotor of an electric machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle. It is also an object of the invention to implement an improved method for manufacturing a contactless energy transfer device.

[0009] This problem is solved by a contactless energy transmission device for a rotor of an electric machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising an inductive transformer which has a currentable primary winding and a spaced-apart and coaxially arranged secondary winding which in turn can be electrically coupled to a winding of the rotor, wherein the primary winding and the secondary winding are each designed as foil windings, wherein the primary winding has a first annular primary insulating element at a first end face of the energy transmission device and a second annular primary insulating element at a second end face of the energy transmission device, which are configured such that the primary winding is insulated from primary flux guide elements by means of the primary insulating elements.and the secondary winding has a first annular secondary insulating element at the first end face of the energy transmission device and a second annular secondary insulating element at the second end face of the energy transmission device, which are configured such that the secondary winding is insulated from secondary flux-guiding elements by means of the secondary insulating elements.

[0010] This power transmission device offers the advantage that the primary and secondary windings are insulated by ring-shaped insulating elements at the end faces of the device. This significantly improves the high-voltage insulation between the windings and the flux guide elements. Furthermore, the coaxial arrangement and the foil winding enhance the mechanical support of the windings, increasing the overall stability and strength of the power transmission device. This is particularly important for reliable operation in a motor vehicle powertrain.

[0011] The use of foil windings in conjunction with the ring-shaped insulating elements on both end faces provides improved mechanical support. This contributes to the structural integrity of the windings by stabilizing their position and reducing vibrations. A stable winding is less susceptible to mechanical damage and deformation, which extends the service life and reliability of the power transmission device.

[0012] The coaxial arrangement of the primary and secondary windings as foil windings also enables effective heat dissipation. The large surface area of ​​the foil windings promotes the release of heat generated by the energy transfer process. The ring-shaped insulation elements also contribute to heat dissipation by acting as heat sinks. This prevents overheating of the windings and improves the thermal stability of the device, which in turn contributes to higher efficiency and a longer service life.

[0013] The precise positioning of the windings by the insulating elements also helps to minimize electromagnetic interference. The ring-shaped insulation shields the windings from external electromagnetic influences, thus reducing unwanted interference. This is particularly important in electric machines and vehicle drive trains, where interference-free power transmission is crucial for the performance and reliability of the overall system.

[0014] For the purposes of this patent application, an energy transfer device is an assembly that serves to transfer electrical energy contactlessly from a stationary part to a rotating part of an electric machine and / or vice versa. This device is particularly suitable for use in a separately excited synchronous machine within the drive train of a motor vehicle.

[0015] The function of the energy transmission device is to ensure the efficient and reliable transfer of electrical energy without a direct electrical connection between the static and rotating components. This is achieved through induction between the primary and secondary windings. For example, the primary winding can be supplied with alternating current, generating an alternating magnetic field that induces a voltage in the coaxially arranged secondary winding. This voltage is then used to supply the rotor winding of the electric machine.

[0016] The structure of the energy transmission device preferably comprises several components, such as the inductive transformer, insulating elements, flux guide elements and / or a potting compound.

[0017] The inductive transformer consists of a primary winding and a coaxially arranged secondary winding. Both windings are foil windings, which allows for a compact design and effective heat dissipation. The primary winding is, for example, electrically connected to an AC power source, while the secondary winding is coupled to the rotor winding.

[0018] A first and a second annular primary insulation element are arranged at the end faces of the primary winding. These elements insulate the primary winding from the primary flux-conducting elements and ensure reliable high-voltage insulation. The insulation elements are configured to preferably enclose at least part of the primary winding and provide mechanical stabilization.

[0019] Similar to the primary winding, a first and a second annular secondary insulation element are arranged at the ends of the secondary winding. These elements insulate the secondary winding from the secondary flux-conducting elements and ensure safe and efficient energy transmission. The secondary insulation elements also contribute to mechanical stability and protect the winding from external influences.

[0020] The primary and secondary flux guide elements are designed to optimally guide and concentrate the magnetic flux. Advantageously, these flux guide elements are made of ferrite, a material with excellent magnetic properties. The primary flux guide elements incorporate at least some of the primary insulation elements, while the secondary flux guide elements incorporate the secondary insulation elements. This improves energy transfer efficiency and reduces losses.

[0021] For additional fixing and insulation, the primary and secondary windings are preferably fixed to their respective insulating elements using a potting compound. This potting compound offers improved mechanical stability, protects the windings from vibrations and mechanical damage, and prevents the ingress of moisture and dirt.

[0022] Inductive transformer

[0023] For the purposes of this patent application, an inductive transformer is a device used for the contactless transmission of electrical energy by induction between two spatially separated windings. This transformer is particularly useful in electrical machines, such as separately excited synchronous machines within the drivetrain of motor vehicles, to enable energy transfer from the stationary part to the rotating part.

[0024] The function of the inductive transformer is to generate a magnetic field through induction, which induces a voltage in a spatially separated winding. This enables contactless energy transfer, minimizing wear and maintenance and increasing the reliability of the entire device. Insulation elements

[0025] For the purposes of this patent application, an insulating element is a component that serves to electrically insulate electrical windings from adjacent components while simultaneously ensuring mechanical stability.

[0026] Insulating elements play a crucial role in the high-voltage insulation and mechanical integrity of power transmission equipment. Their function is to electrically isolate the primary and secondary windings from the primary and secondary flux-conducting elements. This minimizes the risk of electrical flashovers and improves the safety and reliability of the power transmission equipment. Simultaneously, the insulating elements contribute to mechanical stability by holding the windings firmly in place and protecting them from vibration and mechanical stress.

[0027] The insulating elements are advantageously designed in a ring shape to completely enclose the windings and ensure effective insulation at the end faces of the power transmission device. This structure allows for a uniform distribution of mechanical forces and consistent electrical insulation.

[0028] Insulating elements can be made from various materials that possess insulating electrical properties. Materials such as ceramics, glass fiber reinforced plastics, or high-temperature-resistant polymers are preferred. These materials offer high dielectric strength and mechanical stability, even under the demanding conditions of a motor vehicle powertrain.

[0029] The insulation elements can have various cross-sectional profiles to optimize their functionality. C-shaped cross-sectional profiles are preferred, as they offer improved mechanical support and more effective insulation in the area of ​​contact with the windings. This specific shape allows for better adaptation to the windings and prevents their displacement. For additional fixation and insulation, the insulation elements can be coated with a potting compound. This compound is applied between the windings and the insulation elements and hardens, creating a strong and permanent bond. The potting compound protects the windings from vibration, moisture, and mechanical damage, thus contributing to increased service life and reliability of the power transmission device.

[0030] Flow guiding elements

[0031] For the purposes of this patent application, a flux guide element is a component that serves to guide and concentrate the magnetic flux within a power transmission device to ensure efficient and low-loss power transmission. The function of the flux guide element is therefore to guide the magnetic flux generated by the primary winding and concentrate it onto the secondary winding. By selectively controlling the magnetic flux, induction is maximized, resulting in efficient electrical energy transmission. Furthermore, flux guide elements contribute to minimizing stray losses and increasing the overall performance of the power transmission device.

[0032] Flux guide elements are preferably made from materials with high magnetic permeability, such as ferrite or soft magnetic metals. These materials offer excellent magnetic properties by effectively guiding and concentrating the magnetic flux. Ferrite is particularly advantageous due to its low losses and high efficiency at high frequencies.

[0033] The flux guide elements can have different shapes and structures to optimally control the magnetic flux. U-shaped cross-sections that at least partially encompass the insulating elements are preferred. This shape allows for effective concentration of the magnetic flux and improves the mechanical stability of the entire assembly. The flux guide elements can also form a ring shape to ensure uniform magnetic flux distribution around the circumference of the power transmission device. The primary and secondary flux guide elements are preferably designed to at least partially encompass the respective insulating elements. This contributes to mechanical stability and efficient magnetic coupling. The close interlocking with the insulating elements achieves precise alignment and fixation of the windings, which optimizes the performance of the power transmission device.

[0034] The flux guide elements are preferably arranged coaxially to the primary and secondary windings to direct the magnetic flux directly through the windings. This arrangement maximizes the induced voltage in the secondary winding and improves energy transfer efficiency. The precise placement of the flux guide elements also contributes to reducing stray losses.

[0035] Advantageously, the flux guide elements can also be joined to form a one-piece ring. Such a one-piece ring ensures uniform and efficient guidance of the magnetic flux around the entire primary or secondary winding. This improves magnetic coupling and further reduces stray losses, thus increasing energy transfer efficiency. Furthermore, a one-piece ring offers increased mechanical stability and facilitates the assembly and alignment of the flux guide elements within the device.

[0036] Advantageous embodiments of the invention

[0037] According to an advantageous embodiment of the invention, the primary winding and / or the secondary winding can be provided with insulation on their radially outer surface. The additional insulation on the radially outer surface of the primary and / or secondary winding offers the advantage of further improved high-voltage insulation. This insulation protects the windings even better against external influences and mechanical damage, thus increasing the service life and reliability of the power transmission device. Furthermore, it can further minimize the risk of voltage breakdown. For the purposes of this patent application, insulation is therefore a component or layer that serves to electrically isolate electrical conductors or components from one another in order to ensure the safe and reliable operation of the electrical device.This insulation plays a crucial role in high-voltage insulation and the prevention of electrical flashovers, particularly in power transmission devices for electric machines. The insulation can be made of various materials that exhibit electrically insulating properties. Materials such as polyimide films, glass fiber reinforced plastics, or high-temperature-resistant polymers are preferred. These materials offer high dielectric strength and mechanical robustness, making them ideal for use in high-voltage applications.

[0038] The structure and thickness of the insulation can vary to meet the specific requirements of the application. A single- or multi-layer structure is preferred, in which several layers of insulating material are stacked on top of each other to achieve higher dielectric strength and mechanical stability. The insulation thickness is selected to provide sufficient dielectric strength while remaining compact to minimize the device's size. Advantageously, the insulation is fixed using a potting compound, which provides additional mechanical stability and protection against vibration. The potting compound hardens and forms a solid, insulating layer that protects the windings from external influences.

[0039] The insulation can advantageously be designed as an insulating foil wrapped around the winding. This insulating foil is tightly wrapped around the winding to create a uniform and continuous insulating layer. This ensures high dielectric strength and effectively protects the winding from mechanical damage and external influences. The use of insulating foil allows for simple and cost-effective manufacturing of insulated windings.

[0040] According to a further preferred embodiment of the invention, the primary winding can also be wound on a primary support ring and / or the secondary winding on a secondary support ring. Winding the primary and / or secondary winding on a support ring offers the advantage of ensuring mechanical stability and precise positioning of the windings. The support ring provides firm and uniform support for the windings, which better withstands vibrations and mechanical stresses. This contributes to the longevity and reliability of the power transmission device and also facilitates assembly and maintenance.

[0041] For the purposes of this patent application, a support ring is therefore a structural component that serves to mechanically support and precisely position the windings of a power transmission device. The support ring ensures the stable and correct arrangement of the windings within the device and contributes to the overall stability of the power transmission device. This ensures that the windings remain stable during operation of the electric machine and are not displaced by vibrations or mechanical loads. The support ring also promotes the even distribution of mechanical forces and contributes to improving the mechanical integrity and longevity of the device.

[0042] The support ring can be made of various materials that offer high mechanical strength and stability. Materials such as glass fiber reinforced plastics, metal alloys, or high-strength polymers are preferred. The support ring is preferably designed as an annular structure. This annular design ensures a consistent distribution of mechanical loads and minimizes the risk of deformation or damage to the windings. The support ring can also be equipped with specific recesses or fastening elements to facilitate the assembly and fixation of the windings. The windings are advantageously wound directly onto the support ring. This allows for precise positioning and secure fixation of the windings. The direct connection of the windings to the support ring achieves high mechanical stability, which improves the efficiency and reliability of the power transmission device.Furthermore, according to another advantageous embodiment of the invention, the first primary insulation element may have a C-shaped cross-sectional profile in the area of ​​contact with the primary winding, and / or the second primary insulation element may have a C-shaped cross-sectional profile in the area of ​​contact with the primary winding, and / or the first secondary insulation element may have a C-shaped cross-sectional profile in the area of ​​contact with the secondary winding, and / or the second secondary insulation element may have a C-shaped cross-sectional profile in the area of ​​contact with the secondary winding. The C-shaped cross-sectional profiles of the insulation elements in the area of ​​contact with the windings offer the advantage of improved mechanical support and optimized high-voltage insulation. The special shape of the insulation elements allows for better adaptation to the windings and prevents their displacement.This results in increased mechanical strength and reduces the risk of electrical flashovers.

[0043] According to a further particularly preferred embodiment of the invention, the primary flux guide elements may have a U-shaped cross-section and at least partially encompass the primary insulating elements, and / or the secondary flux guide elements may have a U-shaped cross-section and at least partially encompass the secondary insulating elements. The U-shaped cross-section of the flux guide elements and their partial enclosure of the insulating elements offer the advantage of optimizing magnetic flux guidance. This improves energy transfer efficiency and reduces losses. Simultaneously, the shape increases the mechanical stability of the entire arrangement because the flux guide elements and insulating elements are better interlocked.

[0044] Furthermore, the invention can also be further developed such that the first primary insulation element or the second primary insulation element has a connecting element that projects axially from the primary insulation element and through which the primary winding can be electrically connected to an electrical power source. The presence of a connecting element that projects axially from the primary insulation element and enables an electrical connection to the power source offers the advantage of a simple and secure connection of the primary winding to the power source. This facilitates the installation and replacement of the power transmission device and contributes to a secure and stable electrical connection.

[0045] In a further preferred embodiment of the invention, the primary winding may also be fixed to the first primary insulation element and / or the second primary insulation element by means of a potting compound, and / or the secondary winding may be fixed to the first secondary insulation element and / or the second secondary insulation element by means of a potting compound. Fixing the primary and / or secondary winding by means of a potting compound offers the advantage of improved mechanical stability and increased high-voltage insulation. The potting compound protects the windings from vibrations and mechanical damage and prevents the ingress of moisture and dirt.

[0046] This significantly increases the lifespan and reliability of the energy transmission device.

[0047] Thus, for the purposes of this patent application, a casting compound is a liquid or pasty material that is poured into a mold or cavity to form a solid, protective layer or structure after hardening.

[0048] Potting compounds are used to mechanically fix, insulate, and protect electrical components, such as windings and insulating elements, from environmental influences. The function of the potting compound is therefore to increase the mechanical stability of the components within the power transmission device, improve electrical insulation, and protect the components from vibration, moisture, dust, and other harmful influences. Through curing, the potting compound forms a strong and permanent bond between the insulated components, significantly improving the durability and reliability of the device. Potting compounds can be made from various materials, each offering specific properties for the application. Materials such as epoxy resins, polyurethanes, or silicones are preferred.These materials offer high mechanical strength, excellent electrical insulation properties, and resistance to temperature and humidity. Epoxy resins are particularly advantageous due to their high strength and chemical resistance, while polyurethanes impress with their flexibility and abrasion resistance. Silicones are ideal for applications requiring high temperature resistance.

[0049] The potting compound, in liquid or paste form, is applied to the components to be protected, filling all gaps. After application, the potting compound hardens, forming a solid, protective layer. Hardening can occur through chemical reactions or external influences such as heat. Advantageously, the potting compound hardens at room temperature to ensure ease of application.

[0050] It can also be advantageous to further develop the invention such that the primary flux guide elements form a ring shape and / or the secondary flux guide elements form a ring shape. The ring shape of the primary and / or secondary flux guide elements offers the advantage of uniform and effective magnetic flux guidance. This improves the efficiency of energy transfer and reduces losses. The ring structure also ensures a stable mechanical construction that can withstand the stresses encountered during operation.

[0051] Furthermore, it is advantageous that the primary and / or secondary flux guide elements are made of ferrite. The use of ferrite for the primary and / or secondary flux guide elements offers the benefit of excellent magnetic properties. Ferrite has high magnetic permeability and low losses, which further improves energy transfer efficiency. Moreover, ferrite is a robust and durable material that withstands the mechanical and thermal stresses encountered during operation.

[0052] The object of the invention can also be achieved by a method for manufacturing a contactless energy transmission device for a rotor of an electric machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising the following steps:

[0053] • Provision of a primary winding and a secondary winding, each designed as a foil winding;

[0054] • Provision of a first ring-shaped primary insulation element and a second ring-shaped primary insulation element;

[0055] • Provision of a first annular secondary insulation element and a second annular secondary insulation element;

[0056] • Provision of primary and secondary flow control elements;

[0057] • Arrangement of the first ring-shaped primary insulation element on a first end face of the primary winding and the second ring-shaped primary insulation element on a second end face of the primary winding;

[0058] • Arrangement of the first ring-shaped secondary insulation element on a first end face of the secondary winding and the second ring-shaped secondary insulation element on the second end face of the secondary winding;

[0059] • Arrangement of the primary flux guide elements on the first primary insulation element and / or on the second primary insulation element, such that the primary winding is insulated from the primary flux guide elements by means of the primary insulation elements;

[0060] • The secondary flux guide elements are arranged on the first secondary insulating element and / or the second secondary insulating element, such that the secondary winding is insulated from the secondary flux guide elements by means of these elements. The method for manufacturing the contactless energy transfer device offers the advantage of a systematic and efficient production process. The precise arrangement of the insulating and flux guide elements ensures optimal high-voltage insulation and mechanical stability. This results in a high-quality and reliable energy transfer device that meets the requirements of automotive operation.

[0061] The clear separation of the primary and secondary windings by the insulating elements also simplifies the assembly of the power transmission device. The insulating elements serve as fixed reference points, which facilitates the alignment and fastening of the windings. Furthermore, this structure simplifies maintenance, as individual components can be easily identified and replaced without having to disassemble the entire device.

[0062] The described manufacturing process also allows for flexible adaptation of the energy transmission device to various requirements and specifications. The coaxial arrangement and the modular nature of the ring-shaped insulation elements enable easy scaling of the device for different power requirements and applications.

[0063] Finally, the invention can also advantageously be implemented such that a potting compound is introduced at least partially between the primary winding and the first primary insulating element and / or the second primary insulating element and fixed by means of the potting compound, and / or a potting compound is introduced at least partially between the secondary winding and the first secondary insulating element and / or the second secondary insulating element and fixed by means of the potting compound. Introducing the potting compound between the windings and the insulating elements offers the advantage of additional mechanical fixation and improved high-voltage insulation. The potting compound protects the windings from vibrations and mechanical influences and prevents the ingress of moisture. This contributes to increasing the reliability and service life of the power transmission device.The invention will now be explained in more detail with reference to figures, without limiting the general concept of the invention.

[0064] It shows:

[0065] Figure 1 shows an electric machine with a separately excited rotor in a schematic axial sectional view.

[0066] Figure 2 shows a separately excited rotor with a contactless energy transfer device in an exploded axial section view.

[0067] Figure 3 shows a contactless energy transfer device in an axial section view.

[0068] Figure 4 shows the primary-side components of the energy transmission device in an exploded view.

[0069] Figure 5 shows the secondary-side components of the energy transfer device in an exploded view.

[0070] Figure 1 shows a contactless energy transfer device 1 for a rotor 2 of an electric machine 3, in particular a separately excited synchronous machine within a drive train of a motor vehicle. The rotor 2 is configured as an internal rotor and rotates within the hollow cylindrical stator 25.

[0071] For power supply, the rotor 2 has an inductive transformer 4, which has a primary winding 5 capable of conducting current and a secondary winding 6 spaced apart from it and arranged coaxially, which in turn can be electrically coupled to a winding 7 of the rotor 2. In the illustrated embodiment, the primary winding 5 is stationary, while the secondary winding 6 rotates with the rotor 2. The secondary winding 6 is coupled to the rotor 2 via the housing 26.

[0072] On the secondary side, the secondary winding 6 is connected to the winding 7 of the rotor 2 via an intermediate rectifier electronics 23, which is designed in a ring-shaped disk form and arranged coaxially to the rotor axis of rotation, as can be clearly seen in Figure 2.

[0073] As shown in Figure 3, the primary winding 5 and the secondary winding 6 are each designed as foil windings. The primary winding 5 has a first annular primary insulating element 9 at a first end face 8 of the energy transmission device 1 and a second annular primary insulating element 11 at a second end face 10 of the energy transmission device 1, which are configured such that the primary winding 5 is insulated from the primary flux guide elements 12 by means of the primary insulating elements 9, 11.

[0074] Similarly, the secondary winding 6 also has a first annular secondary insulation element 13 at the first end face 8 of the energy transmission device 1 and a second annular secondary insulation element 14 at the second end face 10 of the energy transmission device 1, which are also configured such that the secondary winding 6 is insulated from secondary flux guide elements 15 by means of the secondary insulation elements 13, 14.

[0075] Figure 3 further shows that the primary winding 5 has insulation 16 on its radially outer surface and the secondary winding 6 has insulation 17 on its radially outer surface. The primary winding 5 is wound on a primary support ring 18 and the secondary winding 6 on a secondary support ring 19.

[0076] As shown in Figure 3, both the first primary insulation element 9 and the second primary insulation element 11 have a C-shaped cross-sectional profile in the area of ​​contact with the primary winding 5. Similarly, the first secondary insulation element 13 and the second secondary insulation element 14 each have a C-shaped cross-sectional profile in the area of ​​contact with the secondary winding 6.

[0077] Figure 3 further shows that the primary flow-guiding elements 12 have a U-shaped cross-section and encompass the primary insulation elements 9, 11 at least partially. The secondary flow-guiding elements 15 also have a U-shaped cross-section and encompass the secondary insulation elements 13, 14 at least partially.

[0078] Figure 3 further shows that the second primary insulation element 11 has a connecting element 20 which projects axially from the primary insulation element 9, 11 and through which the primary winding 5 can be electrically connected to an electrical power source. The connecting element 20 has an axially extending channel 24 through which, for example, a connecting cable for the primary winding 5 runs, although this is not shown in Figure 3.

[0079] As can also be seen from Figure 3, the primary winding 5 is fixed to the first primary insulation element 9 and the second primary insulation element 11 by means of a potting compound 21. The secondary winding 6 is also fixed to the first secondary insulation element 13 and the second secondary insulation element 14 by means of a potting compound 22. The potting compounds 21 and 22 can be identical or different.

[0080] A review of Figures 3-5 shows that both the primary flux-guiding elements 12 and the secondary flux-guiding elements 15 are ring-shaped. In the embodiment shown, the primary flux-guiding elements 12 and the secondary flux-guiding elements 15 are made of ferrite. A method for manufacturing the contactless energy transmission device 1 can comprise the following steps: First, a primary winding 5 and a secondary winding 6, each configured as a foil winding, are provided, along with a first ring-shaped primary insulating element 9, a second ring-shaped primary insulating element 11, a first ring-shaped secondary insulating element 13, and a second ring-shaped secondary insulating element 14. Primary flux-guiding elements 12 and secondary flux-guiding elements 15 are also provided.

[0081] Subsequently, the first annular primary insulation element 9 is arranged on a first end face 8 of the primary winding 5 and the second annular primary insulation element 11 on a second end face 10 of the primary winding 5, followed by the arrangement of the first annular secondary insulation element 13 on a first end face 8 of the secondary winding 6 and the second annular secondary insulation element 14 on the second end face 10 of the secondary winding 6.

[0082] The primary flux-guiding elements 12 are then arranged on the first primary insulation element 9 and on the second primary insulation element 11, so that the primary winding 5 is insulated from the primary flux-guiding elements 12 by means of the primary insulation elements 9 and 11. The secondary flux-guiding elements 15 are arranged analogously on the first secondary insulation element 13 and / or on the second secondary insulation element 14, so that the secondary winding 6 is also insulated from the secondary flux-guiding elements 15 by means of the secondary insulation elements 13 and 14.

[0083] Then, a potting compound 21 is introduced, at least section by section, between the primary winding 5 and the first primary insulation element 9 and the second primary insulation element 11, and fixed in place by means of the potting compound 21. Similarly, a potting compound 22 is also introduced, at least section by section, between the secondary winding 6 and the first secondary insulation element 13 and the second secondary insulation element 14, and fixed in place by means of the potting compound 22. The invention is not limited to the embodiments shown 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.If the patent claims and the preceding description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a hierarchy.

[0084] List of reference signs

[0085] 1 Energy transmission device

[0086] 2 Rotor

[0087] 3 electric machine

[0088] 4 transformers

[0089] 5 Primary winding

[0090] 6 Secondary winding

[0091] 7 windings

[0092] 8 Front

[0093] 9 Primary insulation element

[0094] 10 Front

[0095] 11 Primary insulation element

[0096] 12 flow guide elements

[0097] 13 Secondary insulation element

[0098] 14 Secondary insulation element

[0099] 15 flow guide elements

[0100] 16 Insulation

[0101] 17 Insulation

[0102] 18 Primary carriers

[0103] 19 Secondary carrier ring

[0104] 20 connecting element

[0105] 21 Potting compound

[0106] 22 Potting compound

[0107] 23 Rectifier electronics

[0108] 24-channel

[0109] 25 Stator

[0110] 26 cases

Claims

Claims 1. Contactless energy transmission device (1) for a rotor (2) of an electric machine (3), in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising an inductive transformer (4) which has a currentable primary winding (5) and a secondary winding spaced apart and arranged coaxially therefrom (6) which in turn can be electrically coupled to a winding (7) of the rotor (2), wherein the primary winding (5) and the secondary winding (6) are each designed as foil windings, characterized in that the primary winding (5) has a first annular primary insulating element (9) on a first end face (8) of the energy transmission device (1) and a second annular primary insulating element (11) on a second end face (10) of the energy transmission device (1), which are configured such that the primary winding (5) is insulated from primary flux guide elements (12) by means of the primary insulating elements (9, 11), and the secondary winding (6) has a first annular secondary insulating element (13) on the first end face (8) of the energy transmission device (1) and a second annular secondary insulating element (14) on the second end face (10) of the energy transmission device (1),which are configured such that the secondary winding (6) is insulated from secondary flux-guiding elements (15) by means of the secondary insulation elements (13, 14).

2. Energy transmission device (1) according to claim 1, characterized in that the primary winding (5) has insulation (16) on its radially outer surface and / or the secondary winding (6) has insulation (17) on its radially outer surface.

3. Energy transmission device (1) according to claim 1 or 2, characterized in that the primary winding (5) is wound on a primary support ring (18) and / or the secondary winding (6) is wound on a secondary support ring (19).

4. Energy transmission device (1) according to one of the preceding claims, characterized in that the first primary insulation element (9) is in the engagement area with the primary winding (5) has a C-shaped cross-sectional profile and / or the second primary insulation element (11) in the engagement area with the The primary winding (5) has a C-shaped cross-sectional profile and / or the first secondary insulation element (13) is in the engagement area with the The secondary winding (6) has a C-shaped cross-sectional profile and / or the second secondary insulation element (14) has a C-shaped cross-sectional profile in the area of ​​engagement with the secondary winding (6).

5. Energy transmission device (1) according to one of the preceding claims, characterized in that the primary flow guide elements (12) have a U-shaped cross-section and comprise the primary insulation elements (9, 11) at least sectionally and / or the secondary flow guiding elements (15) are U-shaped in cross-section and include the secondary insulation elements (13,14) at least in sections.

6. Energy transmission device (1 ) according to one of the preceding claims, characterized in that the first primary insulation element (9) or the second primary insulation element (11 ) has a connecting element (20) which projects axially out of the primary insulation element (9, 11 ) and via which the primary winding (5) can be electrically connected to an electrical energy source.

7. Energy transmission device (1) according to one of the preceding claims, characterized in that the primary winding (5) is fixed relative to the first primary insulation element (9) and / or the second primary insulation element (11) by means of a potting compound (21) and / or the secondary winding (6) is fixed relative to the first secondary insulation element (13) and / or the second secondary insulation element (14) by means of a potting compound (22).

8. Energy transmission device (1) according to one of the preceding claims, characterized in that the primary flow guide elements (12) form a ring shape and / or the secondary flow guide elements (15) form a ring shape.

9. Energy transmission device (1) according to one of the preceding claims, characterized in that the primary flow guide elements (12) are made of ferrite and / or the secondary flow guide elements (15) are made of ferrite.

10. Method for manufacturing a contactless energy transmission device (1 ) for a rotor (2) of an electric machine (3), in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising the following steps: • Provision of a primary winding (5) and a secondary winding (6), each designed as a foil winding; • Provision of a first ring-shaped primary insulation element (9) and a second ring-shaped primary insulation element (11); • Provision of a first annular secondary insulation element (13) and a second annular secondary insulation element (14); • Provision of primary flow guide elements (12) and secondary flow guide elements (15); • Arrangement of the first ring-shaped primary insulating element (9) on a first end face (8) of the primary winding (5) and of the second ring-shaped primary insulating element (11) on a second end face (10) of the primary winding (5); • Arrangement of the first annular secondary insulation element (13) on a first end face (8) of the secondary winding (6) and of the second annular secondary insulation element (14) on the second end face (10) of the secondary winding (6); • Arrangement of the primary flux guide elements (12) on the first primary insulation element (9) and / or on the second primary insulation element (11) such that the primary winding (5) is insulated from the primary flux guide elements (12) by means of the primary insulation elements (9, 11); • Arrangement of the secondary flux guide elements (15) on the first secondary insulation element (13) and / or on the second secondary insulation element (14) such that the secondary winding (6) is insulated from the secondary flux guide elements (15) by means of the secondary insulation elements (13,14).

11. Method according to claim 10, characterized in that a potting compound (21) is introduced at least sectionally between the primary winding (5) and the first primary insulating element (9) and / or the second primary insulating element (11) and is fixed by means of the potting compound (21) and / or a potting compound (22) is introduced at least sectionally between the secondary winding (6) and the first secondary insulating element (13) and / or the second secondary insulating element (14) and is fixed by means of the potting compound (22).

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