Stator arrangement and method for manufacturing a stator mount

Abstract

The invention relates to a stator arrangement (1) for an 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, wherein 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 a radial direction via the fastening means (8).

Description

[0001] The present invention relates to a stator assembly for an electric axial flux machine, comprising a stator and a stator receptacle connected to the stator. The stator has a disk-shaped stator yoke from which a plurality of stator teeth extend axially, the stator teeth supporting a stator winding. The present invention further relates to a method for producing a stator receptacle.

[0002] Electric motors are increasingly being used to power motor vehicles, creating alternatives to combustion engines that require fossil fuels. Considerable efforts have already been made to improve the everyday suitability of electric drives and also to provide users with the same level of driving comfort they are accustomed to.

[0003] A detailed description of an electric drive can be found in an article in the magazine ATZ, Volume 113, May 2011, pages 360-365, by Erik Schneider, Frank Fickl, Bernd Cebulski, and Jens Liebold, entitled "Highly Integrative 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. A switchable 2-speed planetary gear set is arranged in the power train between the electric motor and the bevel gear differential, 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 climbing ability, acceleration, and energy consumption.Such drive units are also referred to as e-axles or electrically operated drive trains.

[0004] Axial flux machines are also increasingly being used in such electric axles. An axial flux machine is a dynamoelectric machine in which the magnetic flux between the rotor and stator runs parallel to the rotor's axis of rotation. Both the stator and rotor are often largely disc-shaped. Axial flux machines are particularly advantageous when the axial space available is limited in a given application. This is often the case, for example, with the electric drive systems for electric vehicles described above. In addition to the shortened axial length, another 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.

[0005] 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.

[0006] This object is achieved by a stator arrangement for an electrical 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, wherein the stator receptacle has at least one first fastening means which is formed integrally with the stator receptacle, wherein the stator yoke is fixed to the stator receptacle in the radial direction via the fastening means.

[0007] This provides the advantage of enabling simple and efficient assembly thanks to the integrally formed fastening element. The radial fixation of the stator yoke ensures precise alignment of the stator teeth and also facilitates transport and handling of a wound stator during the manufacturing process of the axial flux machine.

[0008] Depending on the application, it may 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. The axial flux machine according to the invention is preferably configured in an I-arrangement.

[0009] In principle, it is also conceivable that the axial flux machine consists of exactly one stator and exactly one rotor.

[0010] In principle, it is also possible for a plurality of I-type and / or H-type rotor-stator configurations to be arranged axially adjacent to one another. In this context, it would also be possible to arrange several I-type rotor-stator configurations axially adjacent to one another. 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 multiple rotor shafts.

[0011] The stator of the electric axial flux machine according to the invention preferably has a stator body with a plurality of stator windings arranged in the circumferential direction. The stator body can be formed as a single piece or segmented in the circumferential direction. The stator body can be formed from a stator core with a plurality of laminated layers of electrical steel. Alternatively, the stator body can also be formed from a pressed soft magnetic material, such as the so-called SMC (Soft Magnetic Compound).

[0012] The rotor of an electric axial flux machine can be designed, at least in part, as a laminated rotor. A laminated rotor is designed with layers in the radial direction. Alternatively, the rotor of an axial flux machine can also have a rotor carrier, which is equipped with magnetic sheets and / or SMC material and with magnetic elements designed as permanent magnets. Preferably, the rotor does not contain any other magnetically conductive materials besides the permanent magnets. In particular, the permanent magnets can also be accommodated in a rotor molded entirely or partially from a plastic.

[0013] A rotor shaft is a rotatably mounted shaft of an electrical machine to which the rotor or rotor body is non-rotatably coupled.

[0014] The electric axial flux machine may 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 electric axial flux machine.

[0015] A control device preferably has a wired or wireless signal input for receiving electrical signals, such as sensor signals. Furthermore, a control device preferably also has a wired or wireless signal output for transmitting electrical signals, in particular.

[0016] Control and / or regulation operations can be performed within the control device. It is particularly preferred that the control device comprises hardware configured to execute software. The control device preferably comprises at least one electronic processor for executing program sequences defined in the software.

[0017] The control device may further comprise 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 may comprise one or more electronic memories in which data can be stored in a modifiable and / or non-modifiable manner.

[0018] A control device can comprise a plurality of control units, which are arranged, in particular, spatially separated 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 performing computing operations for processing data, particularly preferably using software. The control units can preferably be networked with one another, enabling wired and / or wireless data exchange between control units. In particular, it is also possible to network the control units with one another via bus systems present in the motor vehicle, such as the CAN bus or LIN bus.

[0019] Most 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.

[0020] 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.

[0021] 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 greater than 50 km / h, preferably greater than 80 km / h, and in particular greater than 100 km / h can be achieved. The electric motor particularly preferably has an output 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 greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, and most particularly preferably greater than 12,500 rpm. Most preferably, the electric machine has operating speeds between 5,000 and 15,000 rpm, and most preferably between 7,500 and 13,000 rpm.

[0022] 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 electric axle.

[0023] 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 powertrain can be spatially and / or structurally combined and preconfigured, allowing a hybrid module to be integrated into a motor vehicle's powertrain in a particularly simple manner. In particular, an axial flux machine and a clutch system can be present.

[0024] The stator mount can be plate-like, at least in sections. Particularly preferably, the stator mount is designed as a shell, in which a plate-like base is enclosed by a rim extending from it. Most preferably, the stator mount is formed from a sheet metal. In principle, it would also be possible to form the stator mount from a plastic material.

[0025] According to an advantageous embodiment of the invention, the first fastening means can be 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 design 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.

[0026] 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. Preferably, the hook element 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 positive-locking element of the stator yoke. The positive-locking element can be, for example, a groove, a recess, or a ramp element.

[0027] 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.

[0028] 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 element to the inner surface of the annular stator yoke further ensures a secure and stable connection between the stator and the stator mount. The bolt is preferably formed using a forming process and is accordingly hollow-cylindrical.

[0029] Furthermore, the invention can also be further developed such that a second fastening means is designed as a hook element extending axially from the stator receptacle and formed integrally with the stator receptacle, wherein the second fastening means is coupled to the inner circumferential surface of the annular stator yoke. The coupling of the second fastening means to the inner 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. Preferably, the hook element 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 positive-locking element of the stator yoke. The positive-locking element can be, for example, a groove, a recess, or a ramp element.

[0030] In a likewise preferred embodiment variant 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.

[0031] It may also be advantageous to further develop the invention in such a way that a plurality of first fastening means are distributed over the circumference of the outer surface and / or a plurality of second fastening means are distributed over the circumference of the inner 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 holder. The distribution of the fastening means over the circumference ensures a uniform distribution of forces and loads, which leads to a higher load-bearing capacity and robustness of the axial flux machine.

[0032] 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 are formed on the stator holder by means of a forming process. This allows for a high degree of precision and accuracy in the formation of the fastening means to be achieved through the use of forming processes. Furthermore, production by forming processes can be carried out efficiently and cost-effectively.

[0033] 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 disc-shaped stator yoke from which a plurality of stator teeth extend axially, • Provision of a stator winding for winding the stator • Providing a stator holder with at least one first fastening means which is formed integrally with the stator holder and is configured to fix the stator yoke in the radial direction, • Winding the stator with the stator winding • Place the stator holder on the wound stator so that the stator is fixed to the stator holder in the radial direction via the stator yoke.

[0034] The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

[0035] It shows: Fig. 1 an axial flow machine in a schematic axial section, Fig. 2 a stator arrangement of an axial flux machine in an exploded view, Fig. 3 a stator arrangement of an axial flux machine in a perspective view, Fig. 4 a perspective detailed view of a fastening means of the stator holder on the outer surface of the stator yoke, Fig. 5 three embodiments of fastening means, each in a schematic axial sectional view, Fig. 6 three embodiments of fastening means with adapter elements, each in a schematic axial section, Fig. 7 a motor vehicle with an electric drive train in a schematic representation.

[0036] Fig. 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 holder 4, which is part of a motor housing of the axial flux machine 2. As shown in the Fig. As outlined in Figure 7, such an axial flow machine 2 can be installed in a drive train 43 of a motor vehicle 44.

[0037] The Fig. 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.

[0038] 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 from 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.

[0039] The first fastening means 8 is in the embodiments of the Fig. 2-3 and the Fig. 5, Figures a, b, is designed as a bolt 9 extending axially from 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 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. 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 makes it possible, in particular, to handle the stator assembly 1 safely during assembly of the axial flux machine 2. The two bolts 9, 14 lie on a common radial plane, i.e., they are arranged radially aligned with each other.

[0040] As in the Fig. the Fig. 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. In the Fig. 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.

[0041] The fastening means 8, 13 can be formed monolithically with the stator holder 4, in particular by means of a forming process, for example by deep drawing or caulking. Such fastening means 8, 13 are shown in Figures a, b of the Fig. 5 can be seen.

[0042] As shown in Figure ac in the Fig. 6, a first adapter element 12 can also be 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. 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.

[0043] In the embodiments of Figures a,b of the Fig. 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, thus securing the stator 3 radially and axially relative to the stator receptacle 4.

[0044] The Fig. the Fig. 6 shows a further design alternative in which the fastening means 8,13 are each designed as a welded connection.

[0045] Even if it is not explicitly shown in the figures, it is nevertheless possible that a plurality of first fastening means 8 are arranged distributed over the circumference of the outer lateral surface 10 and / or a plurality of second fastening means 13 are arranged distributed over the circumference of the inner lateral surface 15.

[0046] The stator arrangement 1 can be manufactured, for example, as follows: 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 is provided for winding the stator 3. Furthermore, a stator receptacle 4 with at least one first fastening means 8 is provided, which is formed integrally with the stator receptacle 4 and configured to fix the stator yoke 5 in the radial direction.

[0047] Then, first, the stator 3 is wound with the stator winding and subsequently, the stator holder 4 is placed on the wound stator 3 so that the stator 3 is fixed to the stator holder 4 in the radial direction via the stator yoke 5.

[0048] The invention is not limited to the embodiments illustrated in the figures. The above description is therefore not to be considered restrictive, but rather explanatory. The following claims are to be understood in such a way 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. List of reference symbols 1 Stator arrangement 2 axial flux machine 3 Stator 4 Stator holder 5 Stator yoke 6 stator teeth 8 fasteners 9 bolts 10 Shell surface 11 Hook element 12 adapter element 13 Fasteners 14 bolts 15 Shell surface 16 Hook element 17 Adapter element 18 grooves 19 grooves 20 Stator slot 41 Rotor 42 Rotor shaft 43 Drivetrain 44 Motor vehicle QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] ATZ magazine, 113th year, 05 / 2011, pages 360-365 by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold with the title: Highly integrated and flexible electric drive unit for electric vehicles, which probably represents the closest state of the art

[0003]

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 disc-shaped stator yoke (5) from which a plurality of stator teeth (6) extend axially, wherein the stator teeth (6) carry a stator winding, characterized by 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 bythat 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 by 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 bythat 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 by that a second fastening means (13) is designed as a bolt (14) extending axially out of 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). [6] Stator arrangement (1) according to one of claims 2-4, characterized bythat 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 by 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 bythat a plurality of first fastening means (8) are arranged distributed over the circumference of the outer lateral surface (10) and / or a plurality of second fastening means (13) are arranged distributed over the circumference of the inner lateral surface (15). [9] Stator arrangement (1) according to claim 8, characterized by that the plurality of first fastening means (8) and / or the plurality of second fastening means (13) were formed on the stator holder (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 disc-shaped stator yoke (5) from which a plurality of stator teeth (6) extend axially, • Provision of a stator winding for winding the stator (3) • Providing a stator holder (4) with at least one first fastening means (8) which is formed integrally with the stator holder (4) and is configured to fix the stator yoke (5) in the radial direction, • Winding the stator (3) with the stator winding () • Place the stator holder (4) on the wound stator (3) so that the stator (3) is fixed to the stator holder (4) in the radial direction via the stator yoke (5).

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