Stator assembly and method for producing a stator retainer

Abstract

The invention relates to a stator assembly (1) for an electric axial flux machine (2), comprising a stator (3) and a stator retainer (4) which is connected to the stator (3). The stator (3) has a disc-shaped stator yoke (5), from which a plurality of stator teeth (6) extend in an axial direction, wherein the stator teeth (6) support a stator winding, and the stator retainer (4) has at least one first securing means (8) that is integrally formed together with the stator retainer (4). The stator yoke (5) is secured to the stator retainer (4) in the radial direction via the securing means (8).

Description

[0001] P222035 - 1 - Stator arrangement and method for producing a stator receptacle The present invention relates to a stator arrangement for an electric axial flux machine, comprising a stator and a stator receptacle connected to the stator, wherein the stator has a disk-shaped stator yoke from which a plurality of stator teeth extend axially, wherein the stator teeth carry a stator winding. The present invention further relates to a method for producing a stator receptacle. Electric motors are increasingly being used for propulsion in motor vehicles in order to create alternatives to internal combustion engines that require fossil fuels. Considerable efforts have already been made to improve the everyday suitability of electric drives and also to offer users the usual driving comfort. A detailed description of an electric drive can be found in an article in the magazine ATZ 113.Year, 05 / 2011, pages 360-365 by Erik Schneider, Frank Fickl, Bernd Cebulski, and Jens Liebold, titled: Highly Integrated and Flexible Electric Drive Unit for E-Vehicles, which arguably represents the closest state of the art. This article describes a drive unit for one axle of a vehicle. This drive unit comprises an electric motor arranged concentrically and coaxially with a bevel gear differential. In the power train between the electric motor and bevel gear differential, a switchable 2-speed planetary gear set is arranged, which is also positioned coaxially with the electric motor or the bevel gear differential or spur gear differential. The drive unit is very compact and, thanks to the switchable 2-speed planetary gear set, allows a good compromise between gradeability, acceleration, and energy consumption. Such drive units are also referred to as e-axles or electrically operated drive trains.Axial flux machines are also increasingly being used in such electric axles. An axial flux machine is a dynamo-electric machine in which the magnetic flux between the rotor and stator runs parallel to the rotor's axis of rotation P222035 - 2 -. Both the stator and rotor are often largely disc-shaped. Axial flux machines are particularly advantageous when the axially available installation space is limited in a given application. This is often the case, for example, in the electric drive systems for electric vehicles described above. In addition to the shortened axial length, a further advantage of the axial flux machine is its comparatively high torque density. The reason for this is the larger air gap area available in a given installation space compared to radial flux machines.Furthermore, a smaller iron volume is required compared to conventional machines, which has a positive effect on the efficiency of the machine. The object of the invention is to realize a simple and secure fastening of a stator of an axial flux machine to a stator holder. This object is achieved by a stator arrangement for an electrical axial flux machine comprising a stator and a stator holder connected to the stator, wherein the stator has a disk-shaped stator yoke from which a plurality of stator teeth extend axially, wherein the stator teeth carry a stator winding, wherein the stator holder has at least one first fastening means which is formed integrally with the stator holder, wherein the stator yoke is fixed to the stator holder in the radial direction via the fastening means.This has the advantage that the one-piece fastening means enables simple and efficient assembly. The radial fixing of the stator yoke ensures precise alignment of the stator teeth and also transport and handling of a wound stator during the manufacturing process of the axial flux machine. Depending on the area of ​​application, it can be advantageous to design an axial flux machine in an I arrangement or an H arrangement. In an I arrangement, the rotor is arranged axially next to a stator or between two stators. In an H arrangement, two rotors are arranged on opposite axial sides of a stator P222035 - 3 -. The axial flux machine according to the invention is preferably configured in an I arrangement. In principle, it is also conceivable for the axial flux machine to consist of exactly one stator and exactly one rotor.In principle, it is also possible for a plurality of I-type and / or H-type rotor-stator configurations to be arranged axially next to one another. In this context, it would also be possible to arrange several I-type rotor-stator configurations next to one another in the axial direction. In particular, it is also preferable for the H-type and / or I-type rotor-stator configurations to be essentially identical in design, so that they can be combined in a modular manner to form an overall configuration. Such rotor-stator configurations can, in particular, be arranged coaxially to one another and connected to a common rotor shaft or to several rotor shafts. The stator of the electrical axial flux machine according to the invention preferably has a stator body with several stator windings arranged in the circumferential direction. The stator body can be designed as a single piece or in segments when viewed in the circumferential direction.The stator body can be formed from a stator lamination stack with multiple laminated electrical steel layers. Alternatively, the stator body can also be formed from a pressed soft magnetic material, such as the so-called SMC material (Soft Magnetic Compound). The rotor of an electric axial flux machine can be designed at least in part as a laminated rotor. A laminated rotor is layered in the radial direction. Alternatively, the rotor of an axial flux machine can also have a rotor carrier that is correspondingly equipped with magnetic laminations and / or SMC material and with magnetic elements designed as permanent magnets. Preferably, the rotor does not have any other magnetically conductive materials besides the permanent magnets. In particular, the P222035 - 4 - permanent magnets can also be accommodated in a rotor that is completely or partially molded from a plastic.A rotor shaft is a rotatably mounted shaft of an electrical machine to which the rotor or rotor body is rotationally fixedly coupled. The electrical axial flux machine can further comprise a control device. A control device, as can be used in the present invention, serves in particular for the electronic control and / or regulation of one or more technical systems of the electrical axial flux machine. A control device has in particular a wired or wireless signal input for receiving in particular electrical signals, such as sensor signals. Furthermore, a control device likewise preferably has a wired or wireless signal output for transmitting in particular electrical signals. Control operations and / or regulation operations can be carried out within the control device.It is particularly preferred that the control device comprises hardware that is designed to execute software. The control device preferably comprises at least one electronic processor for executing program sequences defined in software. The control device can furthermore have one or more electronic memories in which the data contained in the signals transmitted to the control device can be stored and read out again. Furthermore, the control device can have one or more electronic memories in which data can be stored in a changeable and / or unchangeable manner. A control device can comprise a plurality of control units, which are arranged in particular spatially separate from one another in the motor vehicle.Control units are also referred to as Electronic Control Units (ECUs) or Electronic Control Modules (ECMs) and preferably have electronic microcontrollers for P222035 - 5 - carrying out computing operations for processing data, particularly preferably by means of software. The control units can preferably be networked with one another, so that a wired and / or wireless data exchange between control units is possible. In particular, it is also possible to network the control units with one another via bus systems present in the motor vehicle, such as a CAN bus or LIN bus. Very particularly preferably, the control device has at least one processor and at least one memory, which in particular contains a computer program code, wherein the memory and the computer program code are configured, with the processor, to cause the control device to execute the computer program code.The control unit can particularly preferably comprise power electronics for supplying current to the stator or rotor. Power electronics is preferably a combination of various components which control or regulate a current to the electrical machine, preferably including the peripheral components required for this purpose, such as cooling elements or power supplies. In particular, the power electronics contains one or more power electronics components which are designed to control or regulate a current. These are particularly preferably one or more power switches, e.g. power transistors. The power electronics particularly preferably has more than two, particularly preferably three separate phases or current paths, each with at least one separate power electronics component. The power electronics is preferably designed to provide a power output per phase with a peak power, preferably continuous power, of at least 1,000 W, preferably at least 10.000 W, particularly preferably at least 100,000 W. The electric axial flux machine is intended in particular for use within a drive train of a hybrid or fully electric motor vehicle. In particular, the electric machine is dimensioned such that vehicle speeds of greater than 50 km / h, preferably greater than 80 km / h and in particular greater than 100 km / h can be achieved. Particularly P222035 - 6 - preferably the electric motor has an output of greater than 50 kW, preferably greater than 100 kW and in particular greater than 250 kW. It is further preferred that the electric machine provides operating speeds of greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, most particularly preferably greater than 12,500 rpm. Most preferably, the electric machine has operating speeds between 5,000-15,000 rpm, most preferably between 7,500-13,000 rpm.The electric axial flux machine can preferably also be installed in an electrically operated axle drive train. An electric axle drive train of a motor vehicle comprises an electric axial flux machine and a transmission, wherein the electric axial flux machine and the transmission form a structural unit. In particular, it can be provided that the electric axial flux machine and the transmission are arranged in a common drive train housing. Alternatively, it would of course also be possible for the electric axial flux machine to have a motor housing and the transmission to have a transmission housing, wherein the structural unit can then be effected by fixing the transmission relative to the electric axial flux machine. This structural unit is occasionally also referred to as an e-axle. The electric axial flux machine can particularly preferably also be intended for use in a hybrid module.In a hybrid module, components and functional elements of a hybridized drive train can be spatially and / or structurally combined and preconfigured, allowing a hybrid module to be particularly easily integrated into a motor vehicle drive train. In particular, an axial flux machine and a clutch system can be present. The stator receptacle can be plate-shaped, at least in sections; particularly preferably, the stator receptacle is designed as a shell, with a plate-shaped base enclosed by a rim extending from the base. Most preferably, the stator receptacle is formed from sheet metal. In principle, it would also be possible to form the stator receptacle from a plastic.P222035 - 7 - According to an advantageous embodiment of the invention, it can be provided that the first fastening means is designed as a bolt extending axially out of the stator receptacle and monolithically formed with the stator receptacle, wherein the first fastening means is coupled to the outer circumferential surface of the annular stator yoke. The advantage of this embodiment of the first fastening means is that the monolithically formed bolt allows for greater stability and rigidity, both of the stator receptacle and of the joined stator arrangement. The axial alignment of the bolt enables simple assembly and reliable fastening of the stator yoke to the stator receptacle by axially inserting or plugging in the stator. The coupling of the fastening means to the outer circumferential surface of the annular stator yoke further ensures a secure and stable connection between the stator and the stator receptacle.Preferably, the bolt is formed by means of a forming process and is accordingly designed as a hollow cylinder. According to a further preferred development of the invention, it can also be provided that the first fastening means is designed as a hook element extending axially out of the stator receptacle and formed integrally with the stator receptacle, wherein the first fastening means is coupled to the outer circumferential surface of the annular stator yoke. The coupling of the fastening means to the outer circumferential surface of the annular stator yoke ensures a reliable and stable connection between the stator and the stator receptacle. The orientation of the hook element also enables easy assembly and disassembly of the stator from the axial direction, which can facilitate maintenance and repair of the axial flux machine.The hook element preferably has a spring elasticity acting in the radial direction, which can contribute to realizing an assembly-friendly snap connection between the stator receptacle and the stator. The hook element has a radially inward-facing hook that can engage and lock into a corresponding form-fitting element of the stator yoke. The form-fitting element can be, for example, a groove, a recess, or a P222035 - 8 - ramp element. Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that a first adapter element is arranged between the first fastening means and the stator yoke and via which the stator yoke is positioned on the first fastening means, wherein the first adapter element is coupled to the outer circumferential surface of the annular stator yoke.According to another particularly preferred embodiment of the invention, a second fastening means can be designed as a bolt extending axially from the stator receptacle and monolithically formed with the stator receptacle, wherein the second fastening means is coupled to the inner circumferential surface of the annular stator yoke. The advantage of this design of the second fastening means is that the monolithically formed bolt allows for greater stability and rigidity, both of the stator receptacle and of the joined stator arrangement. The axial alignment of the bolt enables simple assembly and reliable fastening of the stator yoke to the stator receptacle by axially inserting or plugging in the stator.The coupling of the fastening means to the inner surface of the annular stator yoke further ensures a secure and stable connection between the stator and the stator receptacle. The bolt is preferably formed by means of a forming process and is accordingly designed as a hollow cylinder. Furthermore, the invention can also be further developed such that a second fastening means is designed as a hook element extending axially out of the stator receptacle and formed integrally with the stator receptacle, wherein the second fastening means is coupled to the inner surface of the annular stator yoke. The coupling of the second fastening means to the inner surface of the annular stator yoke ensures a reliable and stable connection between the stator and the stator receptacle.The orientation of the hook element also enables easy assembly and disassembly of the stator from the axial direction, which can facilitate maintenance and repair of the P222035 - 9 - axial flux machine. The hook element preferably has a spring elasticity acting in the radial direction, which can contribute to creating an assembly-friendly snap connection between the stator mount and the stator. The hook element has a radially inward-facing hook that can engage and lock into a corresponding positive-locking element of the stator yoke. The positive-locking element can be, for example, a groove, a recess, or a ramp element.In a likewise preferred embodiment of the invention, it can also be provided that a second adapter element is arranged between the second fastening means and the stator yoke and via which the stator yoke is positioned on the second fastening means, wherein the second adapter element is coupled to the inner circumferential surface of the annular stator yoke. It can also be advantageous to further develop the invention such that a plurality of first fastening means are arranged distributed over the circumference of the outer circumferential surface and / or a plurality of second fastening means are arranged distributed over the circumference of the inner circumferential surface. The advantage that can be realized in this way is that a uniform and stable connection is achieved between the stator and the stator receptacle.The distribution of the fastening means over the circumference ensures a uniform distribution of forces and loads, which leads to greater load-bearing capacity and robustness of the axial flux machine. According to a further preferred embodiment of the subject matter of the invention, it can be provided that the plurality of first fastening means and / or the plurality of second fastening means were formed on the stator holder by means of a forming process. This can achieve a high level of precision and accuracy in the formation of the fastening means through the use of forming processes. Furthermore, production by forming processes can be carried out efficiently and cost-effectively.P222035 - 10 - Finally, the object of the invention can also be achieved by a method for producing a stator arrangement comprising the following steps: ^ Providing a stator with a disk-shaped stator yoke from which a plurality of stator teeth extend axially, ^ Providing a stator winding for winding the stator ^ Providing a stator receptacle with at least one first fastening means which is formed integrally with the stator receptacle and is configured to fix the stator yoke in the radial direction, ^ Winding the stator with the stator winding ^ Placing the stator receptacle on the wound stator so that the stator is fixed to the stator receptacle in the radial direction via the stator yoke. The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.It shows: Figure 1 an axial flux machine in a schematic axial sectional view, Figure 2 a stator arrangement of an axial flux machine in an exploded view, Figure 3 a stator arrangement of an axial flux machine in a perspective view, Figure 4 a perspective detailed view of a fastening means of the stator receptacle on the outer surface of the stator yoke, P222035 - 11 - Figure 5 three embodiments of fastening means, each in a schematic axial sectional view, Figure 6 three embodiments of fastening means with adapter elements, each in a schematic axial sectional view, Figure 7 a motor vehicle with an electric drive train in a schematic view. Figure 1 shows an axial flux machine 2 in I-configuration with two axially spaced disc-shaped stators 3, between which the disc-shaped rotor 41 is rotatably mounted on the rotor shaft 42.The stators 3 are fixed to a stator receptacle 4, which is part of a motor housing of the axial flux machine 2. As sketched in Figure 7, such an axial flux machine 2 can be installed in a drive train 43 of a motor vehicle 44. Figures 2-3 show a stator arrangement 1 for the electric axial flux machine 2 comprising a stator 3 and a stator receptacle 4 connected to the stator 3, wherein the stator 3 has a disk-shaped stator yoke 5, from which a plurality of stator teeth 6 extend axially, wherein the stator teeth 6 carry a stator winding, not shown. The stator receptacle 4 has a first fastening means 8, which is formed integrally with the stator receptacle 4, wherein the stator yoke 5 is fixed to the stator receptacle 4 in the radial direction via the fastening means 8.The stator receptacle 4 is bowl-shaped, with a substantially flat base and a border extending axially out of the base at the edge of the stator receptacle 4. In the illustrated embodiments, the stator receptacle 4 is made of sheet metal or plastic. P222035 - 12 - In the embodiments of Figures 2-3 and Figure 5, illustrations a, b, the first fastening means 8 is designed as a bolt 9 extending axially out of the stator receptacle 4 and monolithically formed with the stator receptacle 4, wherein the first fastening means 8, i.e. the bolt 9, is coupled to the outer circumferential surface 10 of the annular stator yoke 5.Furthermore, a second fastening means 13 is provided as a bolt 14 extending axially from the stator receptacle 4 and formed monolithically with the stator receptacle 4, wherein the second fastening means 13 is coupled to the inner circumferential surface 15 of the annular stator yoke 5. As a result, the annular stator yoke 5 is fixed in the radial direction to the stator receptacle via the bolts 9, 14. The bolts 9, 14 are arranged and designed such that they form a slight press fit with the stator yoke 5, so that the stator yoke is also fixed in the axial direction to the stator receptacle 4. This enables, in particular, the stator arrangement 1 to be handled safely during assembly of the axial flow machine 2.The two bolts 9, 14 lie on a common radial plane, i.e. are arranged radially aligned with one another. As can be seen in illustration c of Figure 5, the first fastening means 8 can also be designed as a hook element 11 extending axially out of the stator receptacle 4 and formed integrally with the stator receptacle 4, wherein the first fastening means 8 is coupled to the outer circumferential surface 10 of the annular stator yoke 5. For this purpose, the stator yoke 5 has corresponding grooves 18, 19 into which the respective hook of the hook elements 11, 16 engages in a form-fitting manner, so that the stator 3 is secured radially and axially to the stator receptacle 4.Figure 5 further shows that a second fastening means 13 is designed as a hook element 16 extending axially out of the stator receptacle 4 and formed integrally with the stator receptacle 4, wherein the second fastening means 13 is coupled to the inner circumferential surface 15 of the annular stator yoke 5. The hook elements 11, 16 can be formed monolithically with the stator receptacle 4 or as a separate component that is then fixed to the stator receptacle 4. P222035 - 13 - The fastening means 8, 13 can be formed monolithically with the stator receptacle 4, in particular by means of forming processes, for example by deep drawing or caulking. Such fastening means 8, 13 can be seen in Figures a, b of Figure 5.As shown in Figures 6 a-c, a first adapter element 12 can also be arranged between the first fastening means 8 and the stator yoke 5, via which the stator yoke 5 is positioned on the first fastening means 8, wherein the first adapter element 12 is coupled to the outer circumferential surface 10 of the annular stator yoke 5. Furthermore, a second adapter element 17 is arranged between the second fastening means 13 and the stator yoke 5, and via which the stator yoke 5 is positioned on the second fastening means 13, wherein the second adapter element 17 is coupled to the inner circumferential surface 15 of the annular stator yoke 5. In the embodiments of Figures a, b of Figure 6, the adapter elements 12, 17 are fixed to fastening means 8, 13, which each form a riveted connection with the adapter elements 12, 17.In the embodiment shown in Figure a, the adapter elements 12, 17 engage in grooves 18, 19 formed on the stator yoke 5, while in the embodiment shown in Figure b they engage in a stator groove 20 between two stator teeth 6 and thus fix the stator 3 radially and axially relative to the stator receptacle 4. Figure c of Figure 6 shows a further embodiment alternative in which the fastening means 8, 13 are each designed as a welded connection. Even if not explicitly shown in the figures, it is nevertheless possible for a plurality of first fastening means 8 to be distributed over the circumference of the outer circumferential surface 10 and / or for a plurality of second fastening means 13 to be distributed over the circumference of the inner circumferential surface 15.The stator arrangement 1 can be manufactured, for example, as follows: P222035 - 14 - First, a stator 3 with a disk-shaped stator yoke 5, from which a plurality of stator teeth 6 extend axially, can be provided. Furthermore, a stator winding for winding the stator 3 is provided. Furthermore, a stator receptacle 4 with at least one first fastening means 8 is also provided, which is formed integrally with the stator receptacle 4 and is configured to fix the stator yoke 5 in the radial direction. Then, the stator 3 is first wound with the stator winding and subsequently the stator receptacle 4 is placed onto the wound stator 3, so that the stator 3 is fixed to the stator receptacle 4 in the radial direction via the stator yoke 5. The invention is not limited to the embodiments illustrated in the figures.The above description is therefore not to be considered limiting, but rather explanatory. The following claims are to be understood as meaning that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. Where the claims and the above description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a priority.

[0002] P222035 - 15 - List of reference symbols 1 Stator arrangement 2 Axial flux machine 3 Stator 4 Stator holder 5 Stator yoke 6 Stator teeth 8 Fastening means 9 Bolt 10 Shell surface 11 Hook element 12 Adapter element 13 Fastening means 14 Bolt 15 Shell surface 16 Hook element 17 Adapter element 18 Groove 19 Groove 20 Stator groove 41 Rotor 42 Rotor shaft 43 Drive train 44 Motor vehicle

Claims

P222035 - 16 - Claims 1. Stator arrangement (1) for an electrical axial flux machine (2) comprising a stator (3) and a stator receptacle (4) connected to the stator (3), wherein the stator (3) has a disk-shaped stator yoke (5) from which a plurality of stator teeth (6) extend axially, wherein the stator teeth (6) carry a stator winding, characterized in that the stator receptacle (4) has at least one first fastening means (8) which is formed integrally with the stator receptacle (4), wherein the stator yoke (5) is fixed to the stator receptacle (4) in the radial direction via the fastening means (8). 2.Stator arrangement (1) according to claim 1, characterized in that the first fastening means (8) is designed as a bolt (9) extending axially out of the stator receptacle (4) and formed monolithically with the stator receptacle (4), wherein the first fastening means (8) is coupled to the outer circumferential surface (10) of the annular stator yoke (5).

3. Stator arrangement (1) according to claim 1, characterized in that the first fastening means (8) is designed as a hook element (11) extending axially out of the stator receptacle (4) and formed integrally with the stator receptacle (4), wherein the first fastening means (8) is coupled to the outer circumferential surface (10) of the annular stator yoke (5).

4. Stator arrangement (1) according to claim 1, characterized in that P222035 - 17 - a first adapter element (12) is arranged between the first fastening means (8) and the stator yoke (5), and via which the stator yoke (5) is positioned on the first fastening means (8), wherein the first adapter element (12) is coupled to the outer circumferential surface (10) of the annular stator yoke (5).

5. Stator arrangement (1) according to one of claims 2-4, characterized in that a second fastening means (13) is designed as a bolt (14) extending axially out of the stator receptacle (4) and monolithically formed with the stator receptacle (4), wherein the second fastening means (13) is coupled to the inner circumferential surface (15) of the annular stator yoke (5). 6.Stator arrangement (1) according to one of claims 2-4, characterized in that a second fastening means (13) is designed as a hook element (16) extending axially out of the stator receptacle (4) and formed integrally with the stator receptacle (4), wherein the second fastening means (13) is coupled to the inner circumferential surface (15) of the annular stator yoke (5).

7. Stator arrangement (1) according to one of claims 2-4, characterized in that a second adapter element (17) is arranged between the second fastening means (13) and the stator yoke (5) and via which the stator yoke (5) is positioned on the second fastening means (13), wherein the second adapter element (17) is coupled to the inner circumferential surface (15) of the annular stator yoke (5).

8. Stator arrangement (1) according to one of the preceding claims, characterized in that. P222035 - 18 - a plurality of first fastening means (8) are arranged distributed over the circumference of the outer surface (10) and / or a plurality of second fastening means (13) are arranged distributed over the circumference of the inner surface (15).

9. Stator arrangement (1) according to claim 8, characterized in that the plurality of first fastening means (8) and / or the plurality of second fastening means (13) were formed on the stator receptacle (4) by means of a forming process. 10.Method for producing a stator arrangement (1) comprising the following steps: ^ Providing a stator (3) with a disk-shaped stator yoke (5) from which a plurality of stator teeth (6) extend axially, ^ Providing a stator winding for winding the stator (3) ^ Providing a stator receptacle (4) with at least one first fastening means (8) which is formed integrally with the stator receptacle (4) and is configured to fix the stator yoke (5) in the radial direction, ^ Winding the stator (3) with the stator winding () ^ Placing the stator receptacle (4) on the wound stator (3) so that the stator (3) is fixed to the stator receptacle (4) in the radial direction via the stator yoke (5).

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