Electric machine

Abstract

The invention relates to an electric machine (1) comprising a machine housing (2) and power electronics (4) housed in an inverter housing (3), wherein the inverter housing (3) is connected to the machine housing (2) and an interface (5) is formed between the inverter housing (3) and the machine housing (2), through which at least one electrical conductor (6) is passed and the power electronics (4) is thus electrically connected to a winding (7) of the electric machine (1), wherein the interface (5) is formed by a first housing opening (8) in the machine housing (2) and by a second housing opening (9) in the inverter housing (3), wherein an EMC ring (10) formed from an electrically conductive material is arranged between the machine housing (2) and the inverter housing (3), which surrounds the at least one electrical conductor (6) without contact.

Description

[0001] The present invention relates to an electric machine comprising a machine housing and power electronics housed in an inverter housing, wherein the inverter housing is connected to the machine housing and an interface is formed between the inverter housing and the machine housing, through which at least one electrical conductor is passed and the power electronics are thus electrically connected to a winding of the electric machine, wherein the interface is formed by a first housing opening in the machine housing and by a second housing opening in the inverter housing.

[0002] In the field of electric machines, particularly in vehicle drive trains, the power electronics (PE) housing is often directly attached to the main housing of the electric machine (machine housing) using screws. The electric machine is then typically powered by two sets of three busbars each, which are routed through the housing openings. These busbars carry the necessary electrical currents, but also generate parasitic currents that produce unwanted electromagnetic fields.

[0003] To seal the busbars against external environmental influences, an elastomeric environmental seal is typically used, supplemented by a labyrinth geometry in both housings (LE and machine housing). This labyrinth structure is intended to dampen electromagnetic waves and improve the sealing of the interface. However, it has been shown that the damping of electromagnetic waves by this labyrinth structure is often insufficient.

[0004] Another problem is that the mounting points of the power electronics are too far from the busbars, resulting in an excessively long return path for parasitic currents. This degrades electromagnetic compatibility (EMC) and increases the susceptibility of the electrical machine to interference.

[0005] The described state-of-the-art solutions therefore exhibit several disadvantages and problems. Firstly, the attenuation of electromagnetic waves by the labyrinth geometry is insufficient, leading to inadequate EMC. Secondly, the large distances between the mounting points and the busbars cause long return paths for parasitic currents, impairing the efficiency of the electrical connection and generating additional electromagnetic interference.

[0006] The object of the present invention is therefore to provide an electric machine with improved electromagnetic compatibility at the interface between the inverter housing and the machine housing.

[0007] This problem is solved by an electric machine comprising a machine housing and power electronics housed in an inverter housing, wherein the inverter housing is connected to the machine housing and an interface is formed between the inverter housing and the machine housing, through which at least one electrical conductor is passed and the power electronics are thus electrically connected to a winding of the electric machine, wherein the interface is formed by a first housing opening in the machine housing and by a second housing opening in the inverter housing, wherein an EMC ring formed from an electrically conductive material is arranged between the machine housing and the inverter housing, which surrounds the at least one electrical conductor without contact.

[0008] This combination of features offers the advantage that effective electromagnetic compatibility (EMC) is achieved by arranging an EMC ring made of an electrically conductive material between the machine housing and the inverter housing. The EMC ring surrounds at least one electrical conductor without contact, reducing interference from electromagnetic fields and increasing the reliability of the electrical connection. This ensures a secure and interference-free connection between the power electronics and the winding of the electric machine.

[0009] First, the individual elements of the claimed subject matter of the invention are explained in the order in which they are mentioned in the claim set, and subsequently, particularly preferred embodiments of the subject matter of the invention are described. Machine housing

[0010] For the purposes of this patent application, a machine housing is a structure that encloses and protects the internal components of an electrical machine. The machine housing forms the outer shell of the electrical machine and provides mechanical protection as well as a base for mounting and fixing various components. Furthermore, it protects the internal electrical and mechanical components from external influences such as dust, moisture, and mechanical damage. Additionally, the machine housing provides a stable platform for mounting components such as windings, the rotor, the stator, and other internal parts, thereby ensuring precise alignment and proper functioning of the machine.

[0011] The machine housing is preferably made of a robust and durable material such as metal, especially aluminum or steel. It is also conceivable, in principle, to construct the machine housing from a plastic, particularly a fiber-reinforced plastic. These materials offer the necessary strength and stability to withstand the mechanical and thermal stresses during machine operation. Furthermore, certain areas of the machine housing can be provided with additional coatings to offer corrosion protection or additional insulation.

[0012] The machine housing preferably comprises several components that are connected to form a closed structure. These include, for example, side panels, end caps, and base plates or shell elements.

[0013] A key component of the machine housing is the integration of openings and interfaces through which electrical conductors and other connecting elements pass. These openings are designed to provide an effective seal to prevent the ingress of dirt and moisture, while simultaneously ensuring a safe and reliable electrical connection. Inverter housing

[0014] For the purposes of this patent application, an inverter housing is a structure that encloses and protects the power electronics of an electric machine. The inverter housing forms the outer casing of the inverter and provides mechanical protection as well as a base for mounting and fixing the electronic components.

[0015] The inverter housing is preferably made of a robust and lightweight material such as plastic, in particular polyetheretherketone (PEEK) or polyethylene (PEU). These materials offer the necessary strength and stability to withstand the mechanical and thermal stresses during inverter operation, while maintaining a low weight, which improves the overall efficiency of the electrical machine. Furthermore, certain areas of the inverter housing can be coated with additional layers to provide better protection against electromagnetic interference or thermal effects.

[0016] The inverter housing can consist of several components that are connected to form a closed structure. These include, for example, side panels, covers, and base plates.

[0017] A key feature of the inverter housing is the integration of openings and interfaces through which electrical conductors and other connecting elements pass. These openings are designed to provide an effective seal to prevent the ingress of dirt and moisture, while simultaneously ensuring a safe and reliable electrical connection. interface

[0018] For the purposes of this patent application, an interface is a transition zone between the machine housing and the inverter housing, through which electrical conductors are passed to establish an electrical connection between the power electronics in the inverter housing and the winding of the electric machine in the machine housing.

[0019] The interface enables the safe and efficient transmission of electrical signals and power from the power electronics to the winding of the electric machine. Furthermore, the interface ensures that the electrical connection is protected against external influences such as dust, moisture, and electromagnetic interference. The interface design comprises a first opening in the machine housing and a second opening in the inverter housing. These openings are preferably aligned to ensure precise and stable routing of the electrical conductors. The contours of the two openings are essentially identical and conform to the shape of the EMC ring that surrounds the interface and performs additional functions.

[0020] According to the invention, the interface is equipped with an EMC ring made of an electrically conductive material, which surrounds the at least one electrical conductor without contact. This ensures effective electromagnetic compatibility by shielding electromagnetic interference. The EMC ring also provides a stable mechanical connection between the machine housing and the inverter housing. Case opening

[0021] For the purposes of this patent application, a housing opening is a specially designed opening in a housing which serves to guide at least one electrical conductor or other connecting elements through it and at the same time to ensure a seal against external influences.

[0022] The housing opening allows electrical conductors or other connecting elements to pass from one housing area to another, thus establishing a necessary connection between different components of the electrical machine.

[0023] The housing opening is designed with a precisely shaped contour, preferably adapted to the shape and size of the elements to be inserted through it. The housing opening can also be equipped with additional sealing elements to ensure effective sealing against environmental influences. Preferably, the contour of the housing opening corresponds to the contour of the relevant interface, thus enabling optimal adaptation and integration into the overall system.

[0024] Advantageously, the housing openings are arranged so that they are aligned when the machine housing and the inverter housing are connected. This simplifies assembly and ensures a precise and stable connection. The aligned arrangement also ensures that the EMC ring or other shielding elements can optimally perform their function by increasing electromagnetic compatibility and the mechanical stability of the connection. EMC ring

[0025] For the purposes of this patent application, an EMC ring is a component made of electrically conductive material that serves to shield against electromagnetic interference and is integrated into the interface between the machine housing and the inverter housing of an electric machine. The EMC ring provides effective shielding against electromagnetic interference by dissipating it and thus improving the electromagnetic compatibility (EMC) of the electric machine. The structure of the EMC ring comprises a preferably fully enclosed, ring-shaped structure, preferably made of a metal sheet. This ring has an opening contour that advantageously adapts to the contours of the housing openings of the machine housing and the inverter housing.The EMC ring surrounds the at least one electrical conductor that passes through the interface without contact, thus ensuring that electromagnetic shielding is achieved without direct contact with the conductors. Electrical conductor

[0026] The electrical conductor is preferably configured as a busbar. It is further preferred that a plurality of electrical conductors, preferably configured as busbars, are guided through the interface.

[0027] For the purposes of this patent application, a busbar is an electrically conductive, but unlike a cable, rigid component used to transmit and distribute electrical current between the power electronics and the winding of the electric machine. Busbars are used in particular for connecting the stator windings to the inverter. They enable a direct and robust electrical connection and are designed to handle high currents. The busbar structure preferably comprises one or more metallic conductors mounted on substrates or embedded in insulating materials to ensure electrical insulation. This design ensures high conductivity and mechanical stability, and allows for a compact construction to be optimally accommodated within the limited space available in an electric machine.Preferred embodiments of the busbar can, for example, be designed as flat busbars made of copper or aluminum, which are preferred due to their outstanding electrical conductivity and good heat transfer properties. These can be manufactured in various geometries and cross-sectional areas, depending on the application, to meet specific current capacities and cooling requirements. It is also conceivable to provide multilayer busbars consisting of several layers with alternating conductive and insulating layers. This structure increases electrical safety and offers improved protection against mechanical damage or environmental influences. Furthermore, it can be advantageous to use flexible busbars, made, for example, of conductive films or fabrics, which can be adapted for installations where spatial flexibility is required.This type of busbar is particularly useful for meeting complex geometric requirements in electrical machines. Preferred materials for busbars include copper, due to its excellent conductivity, and aluminum, which offers the advantage of lower weight while still maintaining very good conductivity. In specific applications, alloy metals or composite materials can also be used to achieve an optimal balance between conductivity, mechanical strength, weight, and cost. The busbars preferably have a substantially rectangular cross-section. Advantageously, the surface of the busbar is treated or coated to ensure corrosion resistance and maintain electrical conductivity over a long period.The usual finishing processes can include tinning or the application of silver or nickel layers, which possess both protective and conductivity-enhancing properties. The design of the busbar preferably also takes into account the requirements for simple and secure installation by precisely defining the contact areas for connection with other components. This can be achieved through special shaping or by adding mounting holes and slots to ensure a firm and durable mechanical connection. Advantageous embodiments of the invention

[0028] According to an advantageous embodiment of the invention, the EMC ring can be arranged to contact the machine housing via a first line contact and / or to contact the inverter housing via a second line contact. This ensures a stable mechanical connection and reliable electrical contact, further optimizing electromagnetic shielding.

[0029] According to a further preferred embodiment of the invention, the first housing opening may also have a first opening contour and the second housing opening has a second opening contour, wherein the first housing opening is aligned with the second housing opening and the first opening contour essentially corresponds to the second opening contour, and the EMC ring itself has an opening contour that essentially corresponds to the second opening contour. This achieves precise alignment of the housing openings, which facilitates the assembly of the EMC ring and improves the sealing of the interface. The EMC ring also has a corresponding opening contour, which enables optimal adaptation and integration into the electric machine.

[0030] Furthermore, according to another advantageous embodiment of the invention, the EMC ring can be arranged between the machine housing and the inverter housing in a force-fit and / or form-fit manner. This ensures a firm and secure connection that guarantees both mechanical stability and effective electromagnetic shielding. This arrangement prevents the EMC ring from slipping and ensures reliable, long-term operation.

[0031] According to a further particularly preferred embodiment of the invention, the EMC ring can be formed from a sheet metal part and have the shape of an annular disk. This enables simple and cost-effective manufacturing of the EMC ring as well as easy integration into the electrical machine. The annular disk shape provides a uniform contact surface, which optimizes electromagnetic shielding and increases mechanical stability.

[0032] Furthermore, the invention can also be further developed such that the EMC ring has spring elasticity, so that the EMC ring exerts a spring force against the machine housing and the inverter housing when installed. This ensures constant contact pressure and improves electrical contact as well as mechanical stability. In addition, the spring elasticity can absorb vibrations and mechanical stresses.

[0033] In a further preferred embodiment of the invention, the EMC ring may also have a plurality of slots. These slots increase the flexibility of the EMC ring and facilitate its adaptation to different tolerances and manufacturing variations. Furthermore, the slots can improve heat dissipation and thus reduce the thermal load on the electrical machine.

[0034] It can also be advantageous to further develop the invention such that the EMC ring has at least one positive locking element by means of which the EMC ring is centered on the machine housing and / or the inverter housing. This ensures precise positioning and prevents the EMC ring from slipping, which further improves the electromagnetic shielding.

[0035] According to a further preferred embodiment of the invention, a sealing ring can be arranged on the EMC ring. This offers the advantage of additionally sealing the interface between the machine housing and the inverter housing. This prevents the ingress of dust, moisture, and other contaminants, thereby increasing the service life and reliability of the electric machine.

[0036] For the purposes of this patent application, a sealing ring is an elastic, ring-shaped component that is integrated into an interface to provide a seal against external influences such as moisture, dust and dirt.

[0037] The sealing ring comprises a ring-shaped structure made of an elastic material, preferably rubber or another suitable polymer. This material offers the necessary flexibility and resistance to ensure a durable and effective seal. The sealing ring is preferably designed to fit closely to the contours of the housing openings and the EMC ring to achieve a complete seal.

[0038] Advantageously, the sealing ring is dimensioned to experience slight compression when the machine housing and inverter housing are joined. This compression ensures a reliable seal by firmly conforming the sealing ring to the adjacent surfaces. Furthermore, the sealing ring can be provided with additional properties, such as oil or chemical resistance, to guarantee its functionality in various operating environments.

[0039] Finally, the invention can also be advantageously implemented such that the inverter housing is formed at least partially from a PEU and the EMC ring is in contact with the PEU-formed section of the inverter housing, at least partially. This enables a cost-effective and lightweight design of the inverter housing, while simultaneously ensuring electromagnetic shielding by the EMC ring. The combination of PEU and EMC ring offers an optimal balance between mechanical stability and electromagnetic compatibility.

[0040] The invention will now be explained in more detail with reference to figures, without limiting the general concept of the invention.

[0041] It shows: Fig. 1. An electrical machine in a schematic axial section view, Fig. 2 a motor housing with an EMC ring in a perspective view, Fig. 3 A detailed view of the interface of the electrical machine in an axial section view.

[0042] The Fig. Figure 1 shows an electric machine 1 comprising a machine housing 2 and power electronics 4 housed in an inverter housing 3. The stator 17 with the rotor 16, which is rotatable relative to the stator 17, is arranged in the machine housing 2. The inverter housing 3 is connected to the machine housing 2, and an interface 5 is formed between the inverter housing 3 and the machine housing 2, through which at least one electrical conductor 6 passes and the power electronics 4 is thus electrically connected to a winding 7 of the electric machine 1.

[0043] The interface 5 is formed by a first housing opening 8 in the machine housing 2 and by a second housing opening 9 in the inverter housing 3.

[0044] How to learn from the Fig. As can be seen in Figures 2-3, an EMC ring 10, formed from an electrically conductive material, is arranged between the machine housing 2 and the inverter housing 3. This ring 10 surrounds the at least one electrical conductor 6 without contact. The EMC ring 10 rests against the machine housing 2, forming a first line contact, and against the inverter housing 3, forming a second line contact.

[0045] The overview of Fig. 2 and Fig. Figure 3 also clearly shows that the first housing opening 8 has a first opening contour 11 and the second housing opening 9 has a second opening contour 12, wherein the first housing opening 8 is aligned with the second housing opening 9 and the first opening contour 11 essentially corresponds to the second opening contour 12, the EMC ring 10 in turn having an opening contour 13 that essentially corresponds to the second opening contour 12. As can be clearly seen, the opening contours 11, 12, 13 are triangular with rounded corners.

[0046] The EMC ring 10 is arranged in a force-fit configuration between the machine housing 2 and the inverter housing 3. The EMC ring 10 is formed from a sheet metal part and has the shape of a ring disc. The EMC ring 10 has a spring elasticity, so that when installed, it exerts a spring force against the machine housing 2 and the inverter housing 3. The inverter housing 3 is formed from a PEU (polyelectrical electrical unit), and the EMC ring 10 rests against the PEU section of the inverter housing 3.

[0047] From the Fig. 2-3 further shows that a sealing ring 15 is arranged on the EMC ring 10.

[0048] The illustrated embodiment of the invention thus consists of an EMC ring 10, which has the same shape as the interface 5 between the power electronics 4 and the machine housing 2. In the illustrated embodiment, this interface 5 has a triangular shape, but it can also assume other shapes to adapt to different geometric requirements and installation space limitations.

[0049] The EMC ring 10 is designed to rest on both the inverter housing 3 and the machine housing 2, as is the case, for example, in the Fig.Figure 3 shows this. This is achieved through a precise design of the distance between the two housings, which creates a clamping effect that ensures a stable and secure connection. This clamping effect can alternatively or additionally be achieved through the geometry of the EMC ring 10 itself. For example, the EMC ring 10 could have a special profile whose shape creates a spring effect, thus improving the mechanical stability and electrical conductivity of the connection, although this is not shown in the figures.

[0050] To center the EMC ring 10, molded hooks or edges on the machine housing 2 and / or the inverter housing 3 can be used. These elements ensure that the EMC ring 10 remains precisely positioned and does not slip during operation. This is particularly important to guarantee continuous and reliable electromagnetic shielding.

[0051] The EMC ring 10, in the illustrated design, is flat, which allows for simple and cost-effective manufacturing. A flat EMC ring 10 can, for example, be manufactured by stamping from a sheet of metal. This offers an economical solution but may require a more complex housing design to ensure the necessary clamping and stability. Alternatively, the EMC ring 10 can have a three-dimensional, spring-like geometry. This design increases mechanical strength and adaptability to different installation situations and contributes to improved electromagnetic shielding.

[0052] The EMC ring 10 is preferably manufactured from conductive materials such as steel, aluminum alloys, copper, or brass. These materials offer the necessary electrical conductivity and mechanical stability to ensure effective shielding and a durable connection. Depending on the application and specific requirements, other conductive materials can also be used.

[0053] In a preferred embodiment, the interface 5 can additionally include a separate elastomeric environmental seal. This seal protects against water, salt, and other environmental influences, thus contributing to the longevity of the electrical machine. This seal can be injection-molded as a sealing ring 15 beneath the EMC ring 10, so that only one component is required. This simplifies assembly and reduces the number of individual parts needed. The elastomeric seal, as sealing ring 15, provides additional sealing of the interface, preventing the ingress of moisture and dirt and thus increasing the reliability and service life of the electrical machine.

[0054] In summary, the EMC ring 10 offers an effective solution for improving the electromagnetic compatibility and mechanical stability of the connection between the inverter housing 3 and the machine housing 2. Its design and choice of materials ensure reliable shielding against electromagnetic interference and a durable mechanical connection, while the optional environmental seal provides additional protection against external influences.

[0055] 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 electric machine 2 machine housings 3 Inverter housings 4 Power Electronics 5 Interface 6 ladders 7 windings 8 Housing opening 9 Case opening 10 EMC ring 11 Opening contour 12 Opening contour 13 Opening contour 14 slots 15 sealing rings 16 Rotor 17 Stator

Claims

[1] Electric machine (1) comprising • a machine housing (2) and • power electronics (4) housed in an inverter enclosure (3), • wherein the inverter housing (3) is connected to the machine housing (2) and an interface (5) is formed between the inverter housing (3) and the machine housing (2), through which at least one electrical conductor (6) is passed and the power electronics (4) is thus electrically connected to a winding (7) of the electric machine (1), • wherein the interface (5) is formed by a first housing opening (8) in the machine housing (2) and by a second housing opening (9) in the inverter housing (3), characterized by , that • an EMC ring (10) formed from an electrically conductive material is arranged between the machine housing (2) and the inverter housing (3), which surrounds the at least one electrical conductor (6) without contact. [2] Electric machine (1) according to claim 1, characterized by , that the EMC ring (10) is in contact with the machine housing (2) forming a first line contact and / or is in contact with the inverter housing (3) forming a second line contact. [3] Electric machine (1) according to any one of the preceding claims, characterized by , that the first housing opening (8) has a first opening contour (11) and the second housing opening (9) has a second opening contour (12), wherein the first housing opening (8) is aligned with the second housing opening (9) and the first opening contour (11) substantially corresponds to the second opening contour (12), wherein the EMC ring (10) in turn has an opening contour (13) substantially corresponding to the second opening contour (12). [4] Electric machine (1) according to any one of the preceding claims, characterized by, that the EMC ring (10) is arranged force-fit and / or form-fit between the machine housing (2) and the inverter housing (3). [5] Electric machine (1) according to any one of the preceding claims, characterized by , that the EMC ring (10) is formed from a sheet and has the shape of a ring disc. [6] Electric machine (1) according to any one of the preceding claims, characterized by , that the EMC ring (10) has a spring elasticity, so that the EMC ring (10) exerts a spring force acting against the machine housing (2) and the inverter housing (3) when installed. [7] Electric machine (1) according to any one of the preceding claims, characterized by , that the EMC ring (10) has a plurality of slots (14). [8] Electric machine (1) according to any one of the preceding claims, characterized by, that the EMC ring (10) has at least one positive locking element by means of which the EMC ring (10) is centered on the machine housing (2) and / or the inverter housing (3). [9] Electric machine (1) according to any one of the preceding claims, characterized by , that a sealing ring (15) is arranged on the EMC ring (10). [10] Electric machine (1) according to any one of the preceding claims, characterized by , that the inverter housing (3) is formed at least partially from a PEU and the EMC ring (10) is in contact at least partially with the section of the inverter housing (3) formed from PEU.

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