Electrical machine arrangement

Abstract

Electrical machine arrangement (1) comprising • an electric axial flux machine (2) for driving an electrically powered motor vehicle, comprising a stator (3) and a rotor (4), further comprising • a component (6) supporting the stator (3), as well as • a driven element (100) in rotationally fixed contact with the rotor (4), wherein the rotor (4) is rotatably mounted within the electrical machine arrangement (1) via at least one bearing point (61, 611, 612; 62, 621, 622), wherein a shaft grounding element (11) and a rotor position sensor (12) are arranged in a spatial area, in the radial direction between the rotor shaft (W) and the stator (3) and in the axial direction within the axial extent (X) of the stator (3), • characterized in that a bearing (61) is formed between stator (3) and rotor (4), wherein the bearing (61) has a first bearing point (611) and a second bearing point (612) axially spaced from the first bearing point (611), wherein the shaft grounding element (11) and the rotor position sensor (12) are arranged between the first bearing point (611) and the second bearing point (612).

Description

[0001] The present invention relates to an electrical machine arrangement comprising an electric axial flux machine with a stator and a rotor, a component supporting the stator and an output element in rotationally fixed contact with the rotor, wherein the rotor is rotatably mounted within the electrical machine arrangement via at least one bearing point.

[0002] In electric motors, the position of the parts through which the magnetic field flows is crucial. This applies both to the mechanical structure of the electric motor, which positions the parts relative to each other, and to precise knowledge of the angular position of the rotating parts, which determines the exact current position of the rotor relative to the stator. A precise, rigid mechanical structure is essential because even slight positional deviations between the parts can significantly affect the magnetic flux (for example, due to changes in air gaps). Furthermore, precise knowledge of the rotor's current position is also critical, as the constantly changing position (angular position) of the magnets integrated into the rotating rotor relative to the magnets integrated into the stator must always be known exactly in order to control the electric motor correctly.Therefore, it is important to integrate a rotor position sensor into the mechanical structure of the electric motor in such a way that the sensor can accurately detect the relative position of the magnetically relevant parts, i.e., with the lowest possible tolerance influence. At the same time, the sensor's size and installation conditions must not negatively affect the mechanical structure of the electric motor, ensuring that all parts and assemblies can be designed with sufficient robustness and dimensional accuracy, as well as precisely aligned during assembly.

[0003] In addition to the rotor position sensor, most electric motors also require the integration of elements for grounding the rotor or rotor shaft, as well as elements that electrically insulate the rotor relative to the stator. These grounding and / or insulation elements prevent the electrical voltage induced in the mechanical structural elements of the electric motor from discharging through the bearings or being transferred to adjacent components of the electric motor.

[0004] US 2003 / 0184173A1 discloses an assembly comprising an electric motor in an electric motor housing and a drive support. The electric motor includes at least one stator and one rotor. The rotor is connected to a rotor shaft. The vehicle support includes a hub rotatably mounted to a housing via a bearing block. The electric motor housing is attached to the housing and supports the stator. The rotor shaft is attached to the hub and is supported solely by the housing bearing of the drive support. A shoulder portion of the rotor shaft rests against one end of the hub, thus maintaining a desired air gap between the rotor and the stator.

[0005] US 2009 / 0315544A1 discloses a rotation detection device comprising a plurality of ring-shaped magnetic encoders arranged coaxially and having a different number of magnetic poles, a plurality of magnetic sensors, each operable to detect the magnetic field of the corresponding magnetic encoder and capable of detecting position information within a single magnetic pole of the corresponding magnetic encoder, a phase difference detector for determining the phase difference of magnetic field signals detected by the magnetic sensors, and an angle calculator for calculating an absolute rotation angle of the magnetic encoders based on the detected phase difference.

[0006] DE 10 2018 117 315 ​​A1 relates to a rolling bearing comprising a first bearing ring and a second bearing ring rotatable about a common axis. The two bearing rings are arranged coaxially. The rolling bearing also includes a sensor unit for angular position detection, comprising a rotary encoder arranged on an axial side surface of the first bearing ring and at least one sensor opposite the rotary encoder. The sensor is arranged on the second bearing ring. Furthermore, the rolling bearing includes an electrical discharge element arranged between the two bearing rings to dissipate parasitic currents.

[0007] The present invention is based on the objective of providing a machine arrangement with an electric axial flux machine in which a shaft grounding element and / or a rotor position sensor are integrated into the axial flux machine in such a way that it is optimized with regard to the smallest possible installation space. Advantageously, the optimized installation space should also ensure that the mechanical structure of the axial flux machine is not negatively affected with regard to the introduction of flux into the structure.

[0008] This problem is solved by an electrical machine arrangement with the features of claim 1. An electrical machine arrangement according to the invention comprises an electric axial flux machine for driving an electrically powered motor vehicle, with a stator and a rotor, further comprising a component supporting the stator and an output element in rotationally fixed contact with the rotor. The rotor is rotatably mounted within the electrical machine arrangement via at least one bearing. According to the invention, a shaft grounding element and a rotor position sensor are arranged in a spatial area, in the radial direction between the rotor shaft W and the stator and in the axial direction within the axial extent of the stator.This offers the advantage of providing a machine arrangement with an axial flux machine that, together with an integrated rotor position sensor and an integrated shaft grounding element, occupies a very small installation space. Furthermore, the proposed design does not negatively affect the stability of the axial flux machine's structure. The need for a particularly rigid electric motor structure, high-precision manufacturing of all components, and complex alignment during assembly often conflicts with the requirements of compact design, low weight, high power density, mass production-ready manufacturing processes, and low costs in automotive electric motors.

[0009] With regard to the sensors and the shaft grounding and / or insulating elements, this means that they must be integrated into the electric motor in such a way that they exhibit minimal tolerance influence in two respects. On the one hand, their measurement accuracy and functional reliability must not be unduly affected by tolerances, and on the other hand, the sensors and the shaft grounding and / or insulating elements must not unduly increase the tolerances and elasticities of the electric motor's mechanical structure. The positions proposed within the scope of the invention for a shaft grounding element and / or a rotor position sensor enable high measurement accuracy for the sensors. Furthermore, this ensures high functional reliability for the sensors, the shaft grounding and / or insulating elements, and minimizes their negative influence on the tolerances, stiffness, and installation space requirements of the electric motor.

[0010] Further advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined in a technologically meaningful manner and can define further embodiments of the invention. Furthermore, the features specified in the claims are specified and explained in more detail in the description, which also presents further preferred embodiments of the invention.

[0011] 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 or according to their relevance with regard to the invention, and subsequently particularly preferred embodiments of the subject matter of the invention are described.

[0012] Electrical machines are used to convert electrical energy into mechanical energy and / or vice versa, and usually comprise a stationary part called a stator, armature or rotor, and a part called a rotor or runner which is arranged to be movable relative to the stationary part.

[0013] In the case of electrical machines designed as rotary machines, a distinction is made in particular between radial flux machines and axial flux machines. A radial flux machine is characterized by the fact that the magnetic field lines in the air gap between the rotor and stator extend in a radial direction, while in the case of an axial flux machine, the magnetic field lines in the air gap between the rotor and stator extend in an axial direction.

[0014] The housing encloses the electric machine. It can also contain the control and power electronics. Furthermore, the housing can be part of a cooling system for the electric machine and be designed so that cooling fluid can be supplied to the electric machine via the housing and / or heat can be dissipated to the outside via the housing surfaces. In addition, the housing protects the electric machine and any electronics it may contain from external influences.

[0015] The stator of a radial flux machine is typically cylindrical and generally consists of electrically insulated, layered electrical steel sheets stacked into laminations. This design minimizes eddy currents in the stator caused by the stator field. Slots or fully enclosed recesses are cut into the electrical steel sheet around its circumference, parallel to the rotor shaft, to accommodate the stator winding or parts thereof. Depending on the design, the slots may be closed with locking elements such as wedges or covers to prevent the stator winding from being removed.

[0016] A rotor is the rotating part of an electric machine. The term "rotor" is specifically used when a stator is also present. The rotor typically comprises a rotor shaft and one or more rotor bodies fixed to the shaft. The rotor shaft can also be hollow, which reduces weight and allows lubricant or coolant to reach the rotor bodies. If the rotor shaft is hollow, components such as shafts from adjacent units can extend into or through the rotor without negatively impacting the machine's operation.

[0017] The air gap is the space between the rotor and the stator. In a radial flux machine, this is an axially extending, annular gap with a radial width corresponding to the distance between the rotor and stator bodies. The magnetic flux in an axial flux machine, such as an electric motor in a motor vehicle, is directed axially in the air gap between the stator and rotor, parallel to the axis of rotation of the machine. The air gap in an axial flux machine is therefore essentially annular in shape.

[0018] The magnetic flux in an electric axial flux machine, such as an electric drive motor in a motor vehicle designed as an axial flux machine, is directed axially in the air gap between the stator and rotor, parallel to the axis of rotation of the electric machine. Axial flux machines are distinguished, among other things, by their design: I-arrangement and H-arrangement. An I-arrangement axial flux machine is an electric machine in which a single rotor disk is arranged between two stator halves and is subjected to a rotating electromagnetic field.An axial flux machine in an H-arrangement is an electric machine in which two rotor disks of the electric machine enclose a stator of the electric machine in the annular space axially between them. The two rotor disks can be subjected to a rotating electromagnetic field via the stator. The two rotor disks of an H-arrangement electric machine are mechanically connected to each other. This is usually achieved via a shaft or shaft-like connecting element that projects radially inwards (radially inside the magnets of the electric machine) through the stator and connects the two rotor disks radially inwards. A special form of the H-arrangement is represented by electric machines in which the two rotor disks are connected radially outwards (radially outside the magnets of the electric machine).The stator of this electric machine is then attached radially inwards (usually on one side) to a component that supports the electric machine. This special form of the H-arrangement is also called a J-arrangement.

[0019] A bearing is formed between the stator and rotor. The advantage of this design is that it achieves improved tilting stability of the machine assembly and its components relative to each other.

[0020] According to the invention, the bearing arrangement comprises a first bearing point and a second bearing point axially spaced from the first bearing point. This provides not only a further improvement in tilting stability but also additional protected installation space for accommodating a shaft grounding element 11 and a rotor position sensor.

[0021] Furthermore, according to the invention, the shaft grounding element and / or the rotor position sensor are arranged between the first and second bearing points. The advantage of this design lies in the fact that, within the available axial installation space of the electric machine, the two bearing points can be arranged with the greatest possible axial distance from each other, thereby creating a robust and tilt-resistant bearing base for supporting the rotor and / or connecting the rotor and stator. Moreover, by arranging the shaft grounding element and the rotor position sensor between the first and second bearing points, a compact and reliable arrangement of the components can be achieved.

[0022] According to a further particularly preferred embodiment of the invention, the rotor can be supported by at least one bearing via at least a first bearing point relative to the component supporting the stator. By supporting the rotor against a component supporting the stator and not connecting it directly to the stator via a bearing point, the mechanical stresses acting on the stator structure are reduced. This enables a more cost-effective stator design or allows the stator design to be further optimized with regard to the magnetic properties of the electric machine and its efficiency.

[0023] Furthermore, the invention can also be further developed such that the shaft grounding element and the rotor position sensor are arranged on axially opposite sides of the rotor. If the shaft grounding element and the rotor position sensor are arranged on axially opposite sides of the rotor and occupy approximately the same amount of installation space, this allows for a relatively symmetrical design of the rotor, the rotor shaft, and / or the rotor bearings. This is advantageous with regard to robustness, bearing accuracy, and material utilization of the individual components.

[0024] In a further preferred embodiment of the invention, the shaft grounding element and the rotor position sensor can also be arranged axially on the same side of the rotor. This allows the design of the axial flux machine to be well adapted to asymmetrical installation space conditions, as is the case, for example, with a single-sided bearing of the rotor shaft or when external forces acting asymmetrically on the electric machine necessitate bearings of different dimensions and thus requiring different amounts of installation space. If the shaft grounding element and the rotor position sensor need to be protected from external influences, such as cooling or lubricating media, it can also be advantageous to arrange the shaft grounding element and the rotor position sensor axially on the same side of the rotor in order to house them in the same space that is shielded (or sealed) from external influences.

[0025] It can also be advantageous to further develop the invention such that the shaft grounding element and / or the rotor position sensor is / are arranged outside the axial area formed between the first and second bearing points, adjacent to the first or second bearing point. The advantage of this is that the shaft grounding element and / or the rotor position sensor are more easily accessible from the outside after the electric machine has been assembled. This makes it easier, for example, to readjust the rotor position sensor after the electric machine has been assembled. If the shaft grounding element is easily accessible from the outside, worn shaft grounding elements can also be easily replaced with new ones without having to completely disassemble the electric machine.

[0026] According to a further preferred embodiment of the invention, the shaft grounding element and / or the rotor position sensor can be integrated into a bearing designed as a rolling bearing. Integrating the shaft grounding element and / or the rotor position sensor into a bearing designed as a rolling bearing allows for a particularly compact and space-saving arrangement. The shaft grounding system and the rotor position detection system always have components attached to the two units, which rotate at a relative speed to each other. The shortest possible tolerance chain between the two rotatable units is achieved when the components of the shaft grounding system and / or the rotor position detection system are attached directly to the bearing rings (for example, the inner and outer rings) of the same rolling bearing.Since the geometric deviation that the rotor position sensor or the shaft grounding element then has to compensate for is very small, the rotor position sensor and the shaft grounding element can be made particularly small and compact when they are integrated into a bearing point.

[0027] Finally, the invention can also be advantageously implemented such that the shaft grounding element and / or the rotor position sensor are arranged in a dry chamber formed around them. Protecting the shaft grounding element and / or the rotor position sensor from external influences, for example by a dry chamber, results in particularly high operational reliability, accuracy, and service life. A dry chamber also allows the use of shaft grounding elements optimized for dry environments in electrical machines where a cooling or lubricating fluid can penetrate between the rotor and the stator.

[0028] The invention and its technical context are explained in more detail below with reference to the figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the situations explained in the figures and combine them with other elements and findings from the present description and / or figures. It should be emphasized that the figures, and especially the depicted dimensions, are only schematic. The same reference numerals denote the same objects, so that explanations from other figures may be consulted as needed.

[0029] They show: Fig. 1 an axial flux motor in I-arrangement with shaft grounding ring and rotor position sensor, arranged between two axially spaced bearing points of a bearing between rotor and stator, in an axial section in schematic representation, Fig. 2 a detailed section according to Fig. 1, showing an electrical line connection to the rotor position sensor, Fig. 3 Another example of an axial flux machine in an I-arrangement with another possible arrangement of shaft grounding ring and rotor position sensor, in an axial section in schematic representation, Fig. 4 another example of an axial flux machine in I-arrangement, wherein, in contrast to the embodiment according to Fig. 2 the shaft grounding ring is protected from unwanted external influences by axially arranged sealing elements on both sides, also shown in a schematic axial section, Fig. 5 an embodiment analogous to Fig. 4, wherein the shaft grounding element is integrated into a rolling bearing and protected by means of axially arranged sealing elements on both sides, Fig. 6 Another possible arrangement of shaft grounding ring and rotor position sensor, wherein these are arranged side by side at an axial end region of the rotor shaft, Fig. 7 Another possible arrangement of shaft grounding ring and rotor position sensor, wherein the stator of the axial flux machine is supported in the housing via a flexible torque support, Fig. 8 An axial flux machine in an H-arrangement, with shaft grounding ring and rotor position sensor, arranged between two axially spaced bearing points of a bearing between rotor and stator, in an axial section in schematic representation, Fig. 9 Another example of an axial flux machine in an I-arrangement with a further possibility of arranging the shaft grounding ring and rotor position sensor, in an axial section in schematic representation, wherein the stator is arranged in the housing in a rotationally and displacement-fixed manner and wherein the rotor is supported by a single bearing point in a side wall of the housing, and Fig. 10 an example of an axial flux machine in I-arrangement analogous to the design according to Fig. 9, wherein the stator is arranged in the housing in a rotationally and displacement-resistant manner and wherein the rotor is supported by two axially spaced bearing points in opposite side walls of the housing.

[0030] Fig. Figure 1 shows an electrical machine arrangement 1 comprising an I-configuration axial flux machine 2 for driving an electrically powered vehicle, a housing 7 component 6 supporting the stator 3, and an output element 100 designed as an output shaft and in rotationally fixed contact with the rotor 4. The axial flux machine 2 has a stator 3 and a rotor 4. The rotor 4 is rotatably mounted within the electrical machine arrangement 1 via two axially spaced bearing points 611, 612. Additionally, the output element 100, designed as an output shaft, is supported in the side wall of a housing 7 of the axial flux machine 2 via a further bearing point 622.It is clearly visible that a shaft grounding element 11 and a rotor position sensor 12 are arranged in a spatial area in the form of an annular gap in the radial direction between the rotor shaft W and the stator 3 and in the axial direction within the axial extent X of the stator 3. The rotor shaft W is connected to an external toothing of the output shaft via an internal toothing, the output shaft meshing with the gear of a gear stage 22 via a further external toothing outside the housing 7.

[0031] On the left side of the axial flux machine 2, a bearing point 611 designed as a rolling bearing with an integrated rotor position sensor 12 is shown. The inner and outer bearing rings both have a connection contour next to the raceway for the rolling elements, to which the rotor position sensor 12 is attached. In the Fig. Figure 1 shows the cross-sectional area between the inner and outer rings, available for the rotor position sensor 12, as a cross-hatched area. Parts of the rotor position sensor 12 are connected to the inner bearing ring, and other parts are connected to the outer bearing ring. The rotor position sensor 12 detects the angular position of the sensor parts that are rotationally fixed to the electromagnets of the stator 3 via the outer bearing ring, relative to the parts of the rotor position sensor 12 that are rotationally fixed to the permanent magnets of the rotor 4 via the inner bearing ring. The rotor position sensor 12 thus continuously detects the angular position of the permanent magnets relative to the electromagnets. This information is necessary for the correct control of the electromagnets of the axial flux machine 2.

[0032] Fig. Figure 2 shows a more detailed sectional view of the bearing 611 with an integrated rotor position sensor 12. A component is attached to the inner bearing ring, which has a cylindrical surface and / or an end face as a measuring reference. The circumferential position of these surfaces can be detected by the part of the rotor position sensor 12 attached to the outer bearing ring. The active sensor part attached to the outer ring is connected to a cable. Depending on the design, this part can measure radially against the cylindrical reference surface or axially against the end face oriented orthogonally to the axis of rotation. To enable the circumferential position of the reference surface to be detected, the reference surfaces can have raised areas, recesses, or notches, or consist of areas with different material properties. For example, different materials can be arranged one behind the other in the circumferential direction, or areas can be magnetized differently.

[0033] The Fig. 1 and Fig. Figure 2 shows that in this embodiment, a sleeve H is pressed in between the outer bearing ring and the housing of the stator 3. This sleeve H can be made of electrically non-conductive material to prevent the voltages induced in the rotor 4 or stator 3 by the magnetic fields from discharging through the bearing 611. Current flowing through the rolling contacts of the bearing 611 can damage the bearing. This sleeve H can also be used to provide simple and reliable cable routing for the rotor position sensor 12. As the Fig. As shown in Figure 2, this sleeve H is partially slotted, allowing one or more leads L of the rotor position sensor 12 to pass through the slot or through multiple slots. This makes it possible to connect the rotor position sensor 12 to the outer bearing ring, lay the leads L of the rotor position sensor 12 over the outer bearing ring, and then slide the sleeve H over the outer bearing ring in such a way that the leads L are positioned in the slots and are not damaged by the sleeve H. The bearing 611, rotor position sensor 12, and sleeve H then form a testable unit that can subsequently be pressed into the housing of the stator 3. The radial and / or axial force transmission between the bearing 611 and the housing then occurs via the sleeve H. The sleeve H only needs to have one slot or other shaped recess on its circumference through which all leads L of the rotor position sensor 12 can pass.To ensure that the sleeve H supports the bearing ring as evenly as possible around its circumference and also exhibits the most uniform stiffness possible, it is usually more practical to route several cables L through several slots distributed around the circumference, each slot being only as large as necessary for the respective cable L. To achieve the most uniform stiffness of the sleeve H, it can also be advantageous to provide significantly more slots or differently shaped recesses in the sleeve H than there are sensor cables, and to arrange these identically shaped slots evenly around the circumference of the sleeve H. Once the rolling bearing of bearing point 611 has been pressed into the stator 3 together with the sleeve H, the sensor cable or cable L can be routed radially outwards and attached to the outside of the stator housing.

[0034] It is particularly space-saving if the line L can be laid in existing recesses in the stator housing.

[0035] As an alternative to using a slotted sleeve H, the outer bearing ring or the bearing seat of the stator housing can also be partially slotted in order to route the line L of the rotor position sensor 12 in an axial direction.

[0036] On the right side of the in the Fig. Figure 1 of the axial flux motor shows a rolling bearing at bearing point 612 with an integrated shaft grounding element 11. This rolling bearing has a connection contour on both the inner and outer rings, to which the shaft grounding element 11 and the component forming the contact surface for the shaft grounding element 11 can be attached. In this embodiment, the shaft grounding element 11 is attached to the stationary outer bearing ring and establishes the electrical connection between the outer bearing ring and the contact surface on the inner bearing ring. For this purpose, the shaft grounding element 11 is electrically conductive and always makes contact with the contact surface with a slight contact force. Because the shaft grounding element 11 slides on the circumference of the reference surface, rotational movement between the inner and outer bearing rings is possible without interrupting the electrical conductivity.In this embodiment, the contact surface for the shaft grounding element 11 is not formed directly by the inner bearing ring, but by a separate component. This allows the material and surface treatment of the contact surface to be optimized independently of the material, heat treatment, and surface treatment of the inner bearing ring. For applications where the surface properties of the inner bearing ring are sufficient for shaft grounding, the shaft grounding element 11 can also directly contact the inner bearing ring. Alternatively, the shaft grounding element 11 can also slide on a component mounted on the rotor shaft W or directly on the rotor shaft W, provided its properties are suitable.

[0037] Both rotor bearings (bearing positions 611, 612) of the in the Fig. In the embodiment shown in Figure 1, angular contact ball bearings are arranged in an O-arrangement relative to each other. Of course, rotor position sensors 12 and shaft grounding elements 11 can also be integrated into or attached to bearings of other designs. The shape of the rolling element raceway and the rolling elements themselves, which determine the bearing type, have only a minor influence on the function of the rotor position sensor 12 and the grounding element 11. However, it is important for the rotor position sensor 12 that the bearing rings to which the rotor position sensor 12 or the component forming the reference surface is attached cannot rotate relative to the magnets of the electric motor to which they are assigned. Since even small positional errors of the rotor position sensor 12 can lead to relevant measurement errors and errors in motor control, unwanted movement of the bearing rings on their bearing seat must be prevented in all bearings with an integrated rotor position sensor 12.This can best be prevented by a positive locking mechanism acting in the circumferential direction.

[0038] For the shaft grounding element 11, it is crucial that the bearing rings to which the shaft grounding element 11 is connected are always conductively connected to their neighboring components and that the conductivity between the bearing rings and their bearing seat is not impaired.

[0039] At the in Fig. In the embodiment shown in Figure 1, the rotor bearings (bearing points 611, 612) are arranged at the opposite end regions of the rotor shaft and are thus located radially within the axial end regions of the two stator halves. This arrangement results in the greatest possible bearing spacing within the axial length of the axial flux machine 2, and thus in the largest possible rigid bearing base. In order to position the bearing points 611, 612 so far apart, the rotor position sensor 12 and the shaft grounding element 11 were arranged axially within the two rolling element raceways. In this embodiment, the complex cable routing to the rotor position sensor 12 was accepted in favor of the strip rotor bearing arrangement.

[0040] To simplify cable routing, the bearing of bearing point 611 with integrated rotor position sensor 12 can alternatively be arranged in reverse, so that the rotor position sensor 12 faces away from the rotor 4 and is located near the axial end region of the stator 3. The cable L can then be routed relatively easily along the outside of the stator 3. The bearing point 612 with the shaft grounding element 11 can, of course, also be designed such that the shaft grounding element 11 faces away from the rotor 4 axially and is located near the axial end region of the stator 3.

[0041] Fig. Figure 3 shows another example of an axial flux machine 2 in an I-configuration with a further possible arrangement of the shaft grounding element 11 and the rotor position sensor 12, in a schematic axial section. In this embodiment, the rotor position sensor 12 and the shaft grounding element 11 are not directly connected to the rotor bearings or integrated into the bearing points 611, 612. Rather, they are arranged as separate assemblies near the bearings 611, 612. The rotor position sensor 12 is again arranged on the left side of the rotor 4 of the axial flux machine 2 between the left rotor bearing, which forms the left bearing point 611, and the rotor 4. The active part of the rotor position sensor 12 is again shown as a closely cross-hatched cross-section, which is mechanically and electrically connected to the stator 3 via a mounting plate and a connecting element.The conductors L (not shown in the figure) or other electrical conductors connecting the rotor position sensor 12 to the motor control unit (not shown) can be routed through the connection element and the interior of the stator 3 to the point where the stator 3 is electrically connected to the motor control unit. From an assembly perspective, it may be advantageous to provide a plug and / or connector connection between the connection element of the rotor position sensor 12 and the stator 3. This allows the electrical conductors L required for connecting the rotor position sensor 12 to be installed inside the stator 3 early in the assembly process or even integrated into the plastic parts there (e.g., by casting or overmolding) and only connected to these conductors L later in the assembly process.

[0042] In the rotor position sensor 12 shown in this embodiment, the reference surface, whose bearing is detected by the active sensor elements of the rotor position sensor 12, is formed directly by the rotor base formed from the rotor shaft W. The figure shows one of the recesses distributed around the circumference and integrated into the end face of the rotor base. By directly using the contour of a rotor component that is required anyway as the measurement reference, no installation space is needed for additional components forming the measurement reference, and the tolerance chain between the permanent magnets integrated into the rotor 4 and the measurement reference is also reduced.

[0043] On the right side of rotor 4, the shaft grounding element 11 is visible between the right rotor bearing or the right bearing point 612 and rotor 4. The shaft grounding element 11 is mechanically attached directly to the housing of the stator 3 and electrically connected. Additionally, the shaft grounding element 11 contacts the rotor shaft W and slides on the contact surface formed by the rotor shaft W as the rotor 4 rotates, ensuring a permanently electrically conductive connection between stator 3 and rotor 4. To further ensure that no electrical current can flow through the rotor bearings, the bearing rings can be electrically insulated from the electric motor components to which they are connected (e.g., the stator housing or the rotor shaft W). This can be achieved, for example, by applying non-conductive coatings to the contact surfaces.Alternatively, non-conductive materials can be used for the existing bearing or adjacent components, or for additional components arranged between the bearings and their adjacent components.

[0044] For example, it is possible to use bearings with ceramic components to prevent current flow through the bearings.

[0045] Fig. Figure 4 shows another example of an axial flux machine 2 in an I-arrangement, wherein, in contrast to the embodiment according to Fig. 3 The shaft grounding element 11 is protected from unwanted external influences by axially arranged sealing elements 14 on both sides. The illustrated arrangement is useful, for example, for axial flux machines 2 that have an open cooling concept in which the cooling medium (e.g., oil or a coolant) not only flows through the stator 3 in sealed channels, but can also enter the gap between the stator 3 and rotor 4 and / or the housing 7. The sliding contact between the shaft grounding element 11 and its contact surface must then be protected from the cooling medium (or from lubricants and dirt particles), as this would otherwise impair the conductivity between the two components. In the illustrated embodiment, the sealing elements 14 arranged axially on both sides next to the grounding element 11 are designed as shaft seals. However, other types of seals can also be used.For high-speed electric motors, non-contact seals such as gap seals or labyrinth seals are particularly well-suited. Since almost all seal types exhibit a slight leakage, a drain channel K is provided in this embodiment. This channel allows any fluid that has penetrated the seal to drain out of the dry chamber 13, which is intended for the shaft grounding element 11, at its lowest point. The drain channel K serves both to drain leakage fluid and to allow pressure equalization between the sealed dry chamber 13 and its immediate surroundings. Pressure differences, such as those caused by thermal expansion or changes in atmospheric pressure, could otherwise force fluid through the otherwise sealed sealing elements 14. The drain channel K must terminate at a point where it can be ruled out that fluid is forced into the drain channel K under high pressure.At the same time, the channel cross-section must be large enough to prevent any fluid from rising into the drain channel K by capillary action. The unwanted ingress and ascent of fluid droplets or fluid mist into the channel can also be prevented by filter membranes or other fabric inserts within the channel. In the illustrated embodiment, a bore is present at the lowest point of the cylindrical section of the stator housing into which the shaft grounding element 11 is pressed. This bore allows the leakage fluid to enter a channel located inside the stator 3. To ensure that the leakage fluid, which can collect on both the right and left sides of the shaft grounding element 11, flows into the same bore, the shaft grounding element 11 has a recess in its outer contour in the area of ​​the bore, allowing the fluid to flow into the bore from both sides.The leakage fluid is directed through the channel in the stator to a lateral bore in the stator housing, through which the leakage fluid can flow into the housing 7 of the axial flux machine 2.

[0046] Fig. Figure 5 shows an embodiment analogous to Fig. 4, wherein the shaft grounding element 11 is integrated into a rolling bearing and protected by axially arranged sealing elements 14 on both sides. In this variant, the grounding element 11 is integrated into the rotor bearing or the bearing point 612 of the bearing assembly 61 between rotor 4 and stator 3. A dry space 13 is formed between the outer and inner bearing rings by two sealing elements 14, designed as sealing discs or cover plates, which are attached to the outer bearing ring and seal against the inner bearing ring. The shaft grounding element 11 is located in this dry space. The seal can be provided by contacting seals or non-contacting seals (e.g., gap seals).To allow any leakage fluid that has penetrated to drain away, a radial bore (or other type of recess) is provided in the outer bearing ring at the lowest point of its circumference, to the right and left of the grounding element 11, through which the leakage fluid can flow into a drain channel K in stator 3. The leakage fluid is then discharged via the channel in stator 3.

[0047] Fig. Figure 6 shows another possible arrangement of the shaft grounding element 11 and the rotor position sensor 12, in which they are arranged side by side at an axial end region of the rotor shaft W. An embodiment is shown in which the rotor position sensor 12 and the grounding element 11 are arranged side by side at an axial end region of the rotor shaft W. The rotor position sensor 12 and the grounding element 11 are mounted in a cover-shaped carrier T, through which they can be connected to the stator 3 as a pre-assembled unit. A dry space 13 for the grounding element 11 and the rotor position sensor 12 is created by the cover-shaped carrier T, a cover D in the hollow rotor shaft W, and a sealing element 14 designed as a shaft seal between the cover-shaped carrier T and the rotor shaft W.By sealing the end of the axial flux machine 2 opposite the output shaft with the lid-shaped support T and the lid D, the drying chamber 13 can, in this embodiment, be sealed with a single seal at which differential rotational speed occurs. A channel for draining any leakage fluid that may have entered this drying chamber 13 can also be provided at its lowest point.

[0048] In this embodiment, the rotor position sensor 12 is positioned so that it can detect the end face of the rotor shaft W as a reference surface. The cables or other electrical conductors for connecting the rotor position sensor 12 to the motor control unit can be routed to the outside through the cover-shaped support T (sealed feedthrough) and then along the outside of the stator housing towards the motor control unit. The elements that protect and seal the conductors at the feedthrough point can also form a circumferentially effective positive connection with the stator 3 and thus serve as an anti-rotation device for the rotor position sensor 12. The illustration also shows an alternative bearing arrangement for the rotor 4. The rotor shaft W is supported on each side by a bearing point 611, 612 designed as a deep groove ball bearing on the respective stator half. One side is designed as a fixed bearing and the other side as a floating bearing.

[0049] Fig. Figure 7 shows another possible arrangement of shaft grounding element 11 and rotor position sensor 12, wherein the stator 3 is supported in the housing 7 via a flexible torque support in the form of a so-called length compensation element 8. Fig. Figure 7 is intended to illustrate that the possibilities presented here for functionally arranging the rotor position sensor 12 and / or the shaft grounding elements 11 in a functionally efficient manner within a very small installation space can be combined with very different rotor bearing concepts. In this embodiment, the rotor shaft W is supported by a bearing 62 via two bearing points 621, 622 in opposite side walls of a housing 7 of the axial flux machine 2, and the stator 3 of the axial flux machine 2 is in turn supported on the rotor shaft W by a further bearing 61 via two axially spaced bearing points 611, 612 and additionally secured against unintentional rotation relative to the housing 7 by a torque support 8.

[0050] Fig. Figure 8 shows an axial flux machine 2 in an H-arrangement, with shaft grounding element 11 and rotor position sensor 12, arranged between two axially spaced bearing points 611, 612 of a bearing 61 between rotor 4 and stator 3. Fig. Figure 8 shows an axial flux motor in an H-arrangement, in which the rotor shaft W is supported by a bearing 62 via two bearing points 621, 622 in opposite side walls of a housing 7 of the axial flux machine 2, and in which the stator 3 is supported on the rotor 4 or the rotor shaft W. This is achieved via two axially spaced bearing points 611, 612, designed as rolling bearings. The rotor position sensor 12 is integrated into one of the rolling bearings, and the grounding element 11 is arranged between the two bearings. The figure is intended to illustrate that the possibilities presented here for functionally arranging the rotor position sensor 12 and / or the shaft grounding elements 11 in a very compact installation space can be combined with axial flux machines 2 of different designs. The concepts presented in this invention disclosure are particularly well suited for axial flux motors in I-arrangements, H-arrangements, and J-arrangements.

[0051] Fig. Figure 9 shows another example of an axial flux machine in an I-configuration with a further possible arrangement of the shaft grounding element 11 and the rotor position sensor 12, in a schematic axial section. The stator 3 is arranged in the housing 7 in a rotationally and displacement-resistant manner, while the rotor 4 is supported in a side wall of the housing 7 via a single bearing point 622. The rotor position sensor 12 is arranged axially on one side of the rotor 4 and the shaft grounding element 11 on the other side.

[0052] Fig. Figure 10 shows an example of an axial flux machine in an I-arrangement analogous to the design according to Fig. 9, wherein the stator 3 is also arranged in the housing 7 in a rotationally and displacement-resistant manner and wherein the rotor 4 is supported by two axially spaced bearing points 621, 622 in opposite side walls of the housing 7.

[0053] When the invention refers to a bearing arrangement of the rotor 4 on or opposite the stator 3, it means embodiments in which the stator 3 is fixed in the housing 7 or on the component 6 supporting the stator 3 in a rotationally and laterally fixed manner, and in which the rotor 4 is then supported on the stator 3 by one or more bearing points. A bearing arrangement of the stator 3 on the rotor 4 is defined as when the stator 3 is arranged within the housing 7 – i.e., with a small degree of movement within the housing 7 – via an axially elastic length compensation element 8 and is supported on the rotor 4 by one or more bearing points (embodiments of the Fig. 7 and Fig. 8).

[0054] 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 Electrical machine arrangement 2 Axial flux machine 3 Stator 31 abutments 4 Rotor 41 abutments 6. Component supporting the stator 7 cases 8 Length compensation element 9 Supply line 11 Wave grounding ring 12 Rotor position sensor 13 Drying room 14 Sealing element 22 gear stages 61 Bearing (between rotor and stator) 611 first storage site 612 second storage site 62 Bearing point (between rotor and housing) 621 first storage site 622 second storage site 100 output element L electrical connection cable X axial extent (of the stator) W Rotor shaft H sleeve (for cable routing) K Drainage channel (for liquid) T-beam D lid

Claims

[1] Electrical machine arrangement (1) comprising • an electric axial flux machine (2) for driving an electrically powered motor vehicle, comprising a stator (3) and a rotor (4), further comprising • a component (6) supporting the stator (3), as well as • a driven element (100) in rotationally fixed contact with the rotor (4), wherein the rotor (4) is rotatably mounted within the electrical machine arrangement (1) via at least one bearing point (61, 611, 612; 62, 621, 622), wherein a shaft grounding element (11) and a rotor position sensor (12) are arranged in a spatial area, in the radial direction between the rotor shaft (W) and the stator (3) and in the axial direction within the axial extent (X) of the stator (3), • characterized by, that a bearing (61) is formed between stator (3) and rotor (4), wherein the bearing (61) has a first bearing point (611) and a second bearing point (612) axially spaced from the first bearing point (611), wherein the shaft grounding element (11) and the rotor position sensor (12) are arranged between the first bearing point (611) and the second bearing point (612). [2] Electrical machine arrangement (1) according to claim 1, characterized by , that the rotor (4) is supported by at least one bearing (62) by means of at least one first bearing point (621) relative to the component (6) supporting the stator (3). [3] Electrical machine arrangement (1) according to one of the preceding claims, characterized by , that the shaft grounding element (11) and the rotor position sensor (12) are arranged on axially opposite sides of the rotor (4). [4] Electrical machine arrangement (1) according to one of the preceding claims 1 or 2, characterized by, that the shaft grounding element (11) and the rotor position sensor (12) are arranged axially on the same side of the rotor (4). [5] Electrical machine arrangement (1) according to any one of the preceding claims 1 to 4, characterized by , that the shaft grounding element (11) and / or the rotor position sensor (12) is / are arranged outside the axial area formed between the first bearing point (611) and the second bearing point (612), adjacent to the first bearing point (611) or adjacent to the second bearing point (612). [6] Electrical machine arrangement (1) according to one of the preceding claims, characterized by , that the shaft grounding element (11) and / or the rotor position sensor (12) are integrated into a bearing point (611, 612) designed as a rolling bearing. [7] Electrical machine arrangement (1) according to one of the preceding claims, characterized by, that the shaft grounding element (11) and / or the rotor position sensor (12) are arranged in a dry space (13) formed around them. [8] Electrical machine arrangement (1) according to claim 7, characterized by , that the dry room (13) is sealed by at least one sealing element (14), wherein the at least one sealing element (14) is integrated into or attached to a bearing point (611, 612) designed as a rolling bearing or is arranged spaced apart immediately adjacent to the bearing point (611, 612).

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