Electric axial flux machine

Abstract

The invention relates to an electric axial flux machine (1), in particular for use in the drivetrain of a hybrid-driven motor vehicle or a fully electric-driven motor vehicle, comprising a stator (2) and a rotor (4) separated from the stator (2) by an air gap (3), the stator (2) is accommodated in a pot-shaped annular housing (5) having a housing base (6) extending in a radial direction, the housing base (6) extending through the air gap (3) between the stator (2) and the rotor (4) and the housing (5) being closed on the side axially opposite the housing base (6) by a housing cover (7), the housing cover (7) has at least one first positioning device (8) protruding in the axial direction out of the housing cover (7) or in the axial direction into the housing cover (7), which first positioning device co-operates with a corresponding second positioning device (9) on the stator (2) such that the position of the stator (2) relative to the housing cover (7) is fixed.

Description

Technical Field

[0001] The present invention relates to an electric axial flux machine, in particular an electric axial flux machine for use in a driveline for hybrid or fully electric drive of a motor vehicle, the electric axial flux machine comprising a stator and a rotor separated from the stator by an air gap. Background Art

[0002] Electric motors are increasingly being used to drive motor vehicles to provide an alternative to combustion engines that require fossil fuels. Considerable efforts have been made to improve the suitability of electric drive units for everyday use and to also be able to provide the user with normal driving comfort.

[0003] A detailed description of an electric drive unit can be found in the article titled: Hochintegrativ und Flexibel Elektrische Antriebseinheit für E-Fahrzeuge [Highly integrative and flexible electric drive unit for electric vehicles] by Erik Schneider, Frank Fickl, Bernd Cebulski, and Jens Liebold, published in the magazine ATZ, Volume 113, pages 360 - 365, May 2011. This article may be the latest state of the art. The article describes a drive unit for a vehicle axle that includes an electric motor arranged coaxially with a bevel gear differential. Such a drive unit is also known as an electric axle or an electrically operable driveline.

[0004] Axial flux machines are also increasingly being used in such electric axles. An axial flux machine is an electric machine in which the magnetic flux between the rotor and the stator extends parallel to the axis of rotation of the rotor. Both the stator and the rotor are typically substantially disc-shaped. Axial flux machines are particularly advantageous when the available axial mounting space in a given application is limited. This is typically the case, for example, for the two electric drive systems for the above-mentioned electric vehicles. In addition to the reduced axial length, another advantage of axial flux machines is their relatively high torque density. This is because the available air gap area is larger in a given installation space compared to radial flow machines. Furthermore, a smaller iron volume is required compared to conventional machines, which has a positive effect on the efficiency of the machine.

[0005] Due to its disc-shaped main components, axial flux machines are particularly suitable for applications where a very short overall length of the electric motor is required and a relatively large motor diameter is still acceptable. Thus, when developing a corresponding axial flux machine, it is generally advisable to aim for the shortest possible design, where, however, the outer diameter of the axial flux machine should not be greater than absolutely necessary. In the case of axial flux machines for motor vehicles, there are always additional requirements for low weight, high power density and low cost. Summary of the Invention

[0006] Accordingly, it is an object of the present invention to provide an electric axial flux machine that is inexpensive to manufacture and easy to install.

[0007] This object is achieved by an electric axial flux machine, in particular an electric axial flux machine for use in a driveline of a hybrid-electrically or fully-electrically driven motor vehicle, the electric axial flux machine comprising a stator and a rotor separated from the stator by an air gap, wherein the stator is received in a can-shaped annular housing having a housing base extending in a radial direction, wherein the housing base extends through the air gap between the stator and the rotor and the housing is closed on a side axially opposite to the housing base by a housing cover, wherein the housing cover has at least one first positioning device protruding axially out of the housing cover or at least one first positioning device protruding axially into the housing cover, the first positioning device cooperating with a corresponding second positioning device on the stator such that the position of the stator relative to the housing cover is fixed, and / or the housing cover has at least one third positioning device protruding axially out of the housing cover or at least one third positioning device protruding axially into the housing cover, the third positioning device interacting with a corresponding fourth positioning device on the housing such that the position of the housing relative to the housing cover is fixed.

[0008] This has the advantage that the components of the axial flux machine can be directly positioned relative to each other via these components themselves, which in particular enables a shorter tolerance chain and thus more efficient use of the installation space. For this purpose, the stator and the housing are directly positioned via corresponding positioning devices, which are designed, for example, as moldings or protrusions on the housing cover. The tolerance chains between the stator and the housing cover and between the housing and the stator or the housing cover can be kept as short as possible by this measure. No other assembly aids are required in the tool, which also has a positive effect on the simplicity of assembly and the manufacturing cost.

[0009] First, the individual elements of the subject matter claimed in the present invention are described in the order in which they are mentioned in the grouped claims, and then particularly preferred embodiments of the subject matter of the present invention are described.

[0010] In an electric axial flux machine (AFM), such as an electric drive machine designed as an axial flux machine for a motor vehicle, the magnetic flux between the stator and the rotor is axially directed in the air gap in the direction of rotation of the rotor of the axial flux machine.

[0011] Depending on the application, it may be advantageous to design the axial flux machine in an I-configuration or an H-configuration. In the I-configuration, the rotor is arranged axially adjacent to the stator or between two stators. In the H-configuration, two rotors are arranged on opposite axial sides of the stator. The axial flux machine according to the invention is preferably constructed in an I-configuration.

[0012] In principle, multiple rotor-stator configurations can also be arranged adjacent to each other axially in an I-configuration and / or an H-configuration. In this context, a number of adjacent I-rotor-stator configurations can also be arranged in the axial direction. In particular, it may also be preferred that the H-configuration and / or the I-configuration of the rotor-stator configurations are substantially the same in each case, such that they can be connected together in a modular manner to form an overall configuration. Such rotor-stator configurations can in particular be arranged coaxially with each other and connected to a common rotor shaft or a number of rotor shafts.

[0013] The stator of the electric axial flux machine according to the invention preferably has a stator body which has a number of stator windings arranged in the circumferential direction. When viewed in the circumferential direction, the stator body can be integral or segmented. The stator body can be formed by a stator lamination core having a number of laminated electrical steel sheets. Alternatively, the stator body can also be made of a compressed soft magnetic material, such as so-called SMC (soft magnetic composite) material.

[0014] The stator is accommodated in a housing. The housing can be designed in one or more parts. The housing is preferably made of plastic. The housing can be closed on all sides. Openings can also be provided in the housing, for example to reduce weight or to access components.

[0015] The rotor of the electric axial flux machine can be at least partially designed as a laminated rotor. The laminated rotor is layered in the axial direction. Alternatively, the rotor of the axial flux machine can also have a rotor carrier which is equipped with magnetic sheets and / or SMC material and equipped with magnetic elements designed as permanent magnets.

[0016] The permanent magnets can preferably be inserted into recesses in the laminated rotor core. A single larger rotor magnet or a number of smaller rotor magnets designed as bar magnets can be provided for each recess.

[0017] The rotor preferably has a plurality of rotor bodies. Particularly preferably, the rotor bodies are substantially identical, especially substantially congruent. It is highly preferable that the rotor bodies are formed from identical, especially substantially congruent, rotor laminations. Thus, the rotor bodies are preferably formed from a laminated rotor core which comprises a plurality of laminated individual cover layers or rotor laminations, which individual cover layers or rotor laminations are generally made of electrical steel sheet and which are stacked and encapsulated one on top of the other to form a stack which is referred to as a laminated rotor core. The individual sheets can be held together in the laminated rotor core by gluing, welding or screwing. In particular, the laminated rotor core can also have permanent magnets which are inserted into cavities of the laminated rotor core or fixed around the circumference of the laminated rotor core.

[0018] The rotor shaft is a shaft of the electric machine which is rotatably mounted, to which the rotor or the rotor body is coupled in a rotationally fixed manner.

[0019] The electric axial flux machine can also have control means. The control means, such as the control means which can be used in the present invention, are in particular used for electronically controlling and / or regulating one or more technical systems of the electric axial flux machine.

[0020] The electric axial flux type machine is in particular intended for use in the driveline of a hybrid-electrically driven motor vehicle or a fully electric motor vehicle. In particular, the electric motor is dimensioned such that a vehicle speed of greater than 50 km / h, preferably greater than 80 km / h and in particular greater than 100 km / h can be achieved. It is particularly preferable that the electric motor has an output of greater than 30 kW, preferably greater than 50 kW and in particular greater than 70 kW. It is particularly preferable that the electric axial flux type machine provides a speed of greater than 5000 rpm, particularly preferably greater than 10,000 rpm and very preferably greater than 12,500 rpm.

[0021] The electric axial flux type machine can also preferably be installed in an electrically operable axle driveline. The electric axle driveline of a motor vehicle comprises an electric axial flux type machine and a transmission, wherein the electric axial flux type machine and the transmission form a structural unit. In particular, it can be provided that the electric axial flux type machine and the gearbox are arranged in a common driveline housing. In particular, this driveline housing can also preferably form a connection structure for the axial flux type machine. Alternatively, the electric axial flux type machine can of course also have a motor housing and the gearbox can of course also have a gearbox housing, wherein the structural unit can then be achieved by fixing the gearbox relative to the electric axial flux type machine. This structural unit is sometimes also referred to as an electric axle.

[0022] According to an advantageous embodiment of the invention, it can be provided that the first positioning device and / or the third positioning device are integrally formed, in particular monolithically formed, with the housing cover. The advantage of this design is that the manufacturing costs can be further reduced and the ease of assembly can be further increased.

[0023] According to a further preferred refinement of the invention, it can also be provided that the first positioning device and / or the third positioning device are each designed as a component separate from the housing cover plate. For example, such a separate component can be a guide key.

[0024] Furthermore, according to an equally advantageous embodiment of the invention, it can be provided that the separate component has a feedthrough for at least one electrical conductor from the housing. The advantage of this design is that a higher degree of system integration can be achieved by integrating another function in the separate component, which can also contribute to simplified assembly and reduced manufacturing costs.

[0025] According to another particularly preferred embodiment of the invention, it can be provided that the first positioning device and the third positioning device are designed as a single piece, which can also have a positive impact on the manufacturing costs.

[0026] In addition, the invention can be further developed such that the second positioning device is designed as a recess axially extending into the stator. The advantage of this design is that such a recess can be relatively easily implemented in the stator, which can again contribute to the cost-effective production of the axial flux type machine.

[0027] In an equally preferred embodiment of the invention, it can also be provided that the housing cover has a cylindrical annular section extending axially towards the rotor, on which at least one fifth positioning device projecting radially into the cylindrical annular section or extending out of the cylindrical annular section is provided, and the fifth positioning device interacts with a corresponding sixth positioning device on the housing such that the position of the housing relative to the housing cover is fixed. This can also provide an advantageous variant for the positioning of the components relative to each other in terms of production technology.

[0028] It can also be advantageous to further develop the invention such that the fifth positioning device is formed as a single piece, in particular monolithically formed, with the cylindrical annular section, which can again provide production-related advantages. However, according to another preferred embodiment of the object of the invention, it can also be provided that the fifth positioning device is designed as a component separate from the cylindrical annular section, for example as a guide key.

[0029] Finally, the invention can also be advantageously implemented such that the axial flux type machine is configured in an I-shaped arrangement. Description of the Drawings

[0030] In the following, the present invention will be described in more detail with reference to the accompanying drawings without limiting the general concept of the present invention.

[0031] In the accompanying drawings:

[0032] Figure 1 A schematic axial cross-sectional view of an electric axial flux type machine is shown,

[0033] Figure 2 A first embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view,

[0034] Figure 3 A second embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view,

[0035] Figure 4 A third embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view,

[0036] Figure 5 A fourth embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view,

[0037] Figure 6 A fifth embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view,

[0038] Figure 7 A sixth embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view,

[0039] Figure 8 A seventh embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view and the stator body is shown in a perspective view,

[0040] Figure 9 An eighth embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view,

[0041] Figure 10 A ninth embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view and a cross-sectional view,

[0042] Figure 11 A tenth embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view and a cross-sectional view,

[0043] Figure 12 An eleventh embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-sectional view,

[0044] Figure 13The twelfth embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-section.

[0045] Figure 14 The thirteenth embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-section.

[0046] Figure 15 The fourteenth embodiment of the stator of an electric axial flux type machine is shown in a schematic axial cross-section. Detailed Embodiment

[0047] Figure 1 An electric axial flux type machine 1 is shown, in particular an electric axial flux type machine for use in a driveline of a hybrid or fully electric motor vehicle. The electric axial flux type machine includes a stator 2 having a stator winding 23 and a rotor 4 separated from the stator 2 by an air gap 3. The axial flux type machine 1 is configured in an I-shaped arrangement such that the axial flux type machine 1 is a mirror image of the radial plane of the rotor 4. For clarity, the right stator is not labeled with a reference numeral. However, it should be understood that this is essentially a mirror image of the left stator 2.

[0048] The stator 2 is received in a can-shaped annular housing 5 having a housing base 6 extending in the radial direction, wherein the housing base 6 extends through the air gap 3 between the stator 2 and the rotor 4, and the housing 5 is closed on the side axially opposite the housing base 6 by a housing cover 7. Thus, the housing 5 resembles the shape of a doughnut.

[0049] The housing 5 is sealed against the housing cover 7 by a sealing ring 28 and axially fixed by a fixing ring 29.

[0050] The housing cover 7 has at least one first positioning device 8 protruding axially out of the housing cover 7 or axially into the housing cover 7, and the first positioning device interacts with a corresponding second positioning device 9 on the stator 2 such that the position of the stator 2 relative to the housing cover 7 is fixed. In addition, the housing cover 7 may have at least one third positioning device 10 protruding axially out of the housing cover 7 or axially into the housing cover 7, and the third positioning device interacts with a corresponding fourth positioning device 9 on the housing 5 such that the position of the housing 5 relative to the housing cover 7 is fixed. This results in many configuration options, which will be described in detail below using Figures 2 to 11 to elaborate on these configuration options.

[0051] Figure 2There is shown an embodiment in which the first positioning device 8 and the third positioning device 10 are each formed as a single piece with the housing cover 7, in particular integrally formed and protruding axially from the housing cover 7. For example, the positioning devices 8, 10 can be formed by riveting. Accordingly, the positioning devices 8, 10 have a pin-shaped design, wherein the first positioning device 8 engages in a corresponding recess (second positioning device 9) of the stator 2, and the second positioning device 10 engages in a corresponding recess (fourth positioning device 19) formed on the radially inner circumference of the housing 5 of the housing 5. Also in order to achieve the centering of the components relative to each other, it is proposed to form at least three pin-shaped positioning devices 8, 10 on the circumference of the housing cover 7. If there is centering, for example via a centering diameter, the pin-shaped positioning devices 8, 10 are sufficient for the circumferential positioning of the corresponding components.

[0052] Figure 3 There is shown Figure 2 a slightly modified embodiment in which the first positioning device 8 and the third positioning device 10 are designed as a single piece and are located in the radially inner circumferential region of the housing 5. The one-piece positioning devices 8, 10 are also integrally formed by the housing cover 7 by means of riveting.

[0053] In Figure 4 there is shown a modification of a solution known from Figure 3 In this case, the first positioning device 8 and the third positioning device 10 are designed together, but as a component 12 separate from the housing cover 7. The separate component 12 is a guide key and is located in the radially inner region of the housing 5. As shown in Figure 6 it is also possible to perform the positioning in the radially outer region of the housing 5.

[0054] As can be seen in Figure 7 this embodiment, the separate component 12 has a feedthrough 14 for at least one electrical conductor 13 from the housing 5, wherein the electrical conductor 13 is provided for supplying power to the stator winding 23.

[0055] Figure 5 There is shown Figure 2 a slight modification of an embodiment already known from

[0056] Figure 8An alternative design is shown in which the second positioning device 9 is designed to extend axially into a recess 11 in the stator 2. On the side of the stator 2 facing the housing cover 7, a large number of such recesses 11 can extend radially through the annular disk-shaped stator yoke 21 of the stator body 20, and these recesses serve as cooling channels 24. The stator body 20 also has stator teeth 22 extending axially out of the stator yoke 21. Thus, the cooling channels 24 can now be used to provide recesses 11 in the stator 2, into which the first positioning device 8 engages. Then, the recesses 11 form the second positioning device 9. In the case where the stator 2 is wound from metal strips, it makes sense to support the position between the housing cover plate 7 and the stator 2 as radially inwards as possible, because the wound stator 2 has the highest precision in this area.

[0057] Thus, the cooling fluid 25 can be fed through the housing cover 7 via the cooling fluid inlet 26 and supplied to the cooling channels 24. Then, the cooling fluid 25 leaves the stator area again through the outlet 27 in the upper radial region of the housing 5.

[0058] Figure 9 The embodiment in Figure 8 is basically corresponding to the embodiment in

[0059] Figures 10 to 11 Two embodiments are shown in which the housing cover 7 has a cylindrical annular section 15 extending axially towards the rotor 4, on which at least one fifth positioning device 16 protruding radially into or extending out of the cylindrical annular section 15 is formed, and the fifth positioning device interacts with a corresponding sixth positioning device 17 on the housing 5 such that the position of the housing 5 relative to the housing cover 7 is fixed. Figure 10 An embodiment is shown in which the fifth positioning device 16 is formed as one piece, in particular integrally, with the cylindrical annular section 15. Thus, the positioning of the housing 5 can be carried out, for example, via plug-in teeth (form fit) on the cylindrical annular section 15. As can be seen from the figure, in the shown embodiment, the axial flux type machine 1 has a housing cover 7 and a hub connected to the housing cover 7 via a welded joint, and the hub forms the cylindrical annular section 15. If the housing cover 7 is centered in diameter, the toothed positioning device 16 is sufficient to maintain the circumferential position, as shown in Figure 10 . Otherwise, at least three toothed positioning devices 16 are required to additionally center the housing 5.

[0060] InFigure 11 In the embodiment shown, the fifth positioning device 16 is designed as a component 18 separated from the cylindrical annular section 15, for example, designed as a guide key.

[0061] Figures 12 to 15 Other embodiments of the present invention are shown, in which the housing base 6 and / or the housing cover 7 are also positioned above the stator 2. In other respects, these embodiments correspond to those Figures 2 to 7 known from

[0062] The present invention is not limited to the embodiments shown in the drawings. Therefore, the above description should be regarded as explanatory rather than restrictive. The following claims should be understood to mean that the described features exist in at least one embodiment of the present invention. This does not exclude the existence of other features. Where the patent claims and the above description define a "first" feature and a "second" feature, such naming is used to distinguish between two similar features and does not establish a priority order.

[0063] List of reference numerals

[0064] 1 Axial flux type machine

[0065] 2 Stator

[0066] 3 Air gap

[0067] 4 Rotor

[0068] 5 Housing

[0069] 6 Housing base

[0070] 7 Housing cover

[0071] 8 Positioning device

[0072] 9 Positioning device

[0073] 10 Positioning device

[0074] 11 Recess

[0075] 12 Component

[0076] 13 Conductor

[0077] 14 Feedthrough

[0078] 15 Cylindrical annular section

[0079] 16 Positioning device

[0080] 17 Positioning device

[0081] 18 Component

[0082] 19 Positioning device

[0083] 20 Stator body

[0084] 21 Stator yoke

[0085] 22 Stator teeth

[0086] 23 Stator winding

[0087] 24 Cooling channel

[0088] 25 Cooling fluid

[0089] 26 Cooling fluid inlet

[0090] 27 Cooling fluid outlet

[0091] 28 Sealing ring

[0092] 29 Fixed ring

Claims

1. An electric axial flux machine (1), in particular an electric axial flux machine for use in a driveline of a hybrid-electrically driven motor vehicle or a fully electric motor vehicle, the electric axial flux machine comprising a stator (2) and a rotor (4) separated from the stator (2) by an air gap (3), characterized in that, the stator (2) is received in a can-shaped annular housing (5) having a housing base (6) extending in a radial direction, wherein the housing base (6) extends through the air gap (3) between the stator (2) and the rotor (4), and the housing (5) is closed on a side axially opposite to the housing base (6) by a housing cover (7), wherein, the housing cover (7) has at least one first positioning device (8) protruding axially out of the housing cover (7) or protruding axially into the housing cover (7), the first positioning device interacting with a corresponding second positioning device (9) on the stator (2) such that the position of the stator (2) relative to the housing cover (7) is fixed, and / or the housing cover (7) has at least one third positioning device (10) protruding axially out of the housing cover (7) or protruding axially into the housing cover (7), the third positioning device cooperating with a corresponding fourth positioning device (19) on the housing (5) such that the position of the housing (5) relative to the housing cover (7) is fixed.

2. The axial flux machine (1) according to claim 1, characterized in that, the first positioning device (8) and / or the third positioning device (10) is / are formed integrally with the housing cover (7), in particular integrally formed.

3. The axial flux machine (1) according to claim 1 or 2, characterized in that, the first positioning device (8) and / or the third positioning device (10) are each designed as a component (12) separate from the housing cover (7).

4. The axial flux machine (1) according to claim 3, characterized in that, the separate component (12) has a feedthrough (14) for at least one electrical conductor (13) from the housing (5).

5. The axial flux machine (1) according to any one of the preceding claims, characterized in that, the first positioning device (8) and the third positioning device (10) are designed as a single piece.

6. The axial flux machine (1) according to any one of the preceding claims, characterized in that, the second positioning device (9) is designed as a recess (11) extending axially into the stator (2).

7. The axial flux machine (1) according to any one of the preceding claims, characterized in that, The housing covering (7) has a cylindrical annular section (15) that extends in the axial direction towards the rotor (4), and on the cylindrical annular section, at least one fifth positioning device (16) projects into or extends out of the cylindrical annular section (15) in the radial direction, and the fifth positioning device interacts with a corresponding sixth positioning device (17) on the housing (5) such that the position of the housing (5) relative to the housing covering (7) is fixed.

8. The axial flux machine (1) according to claim 7, characterized in that the fifth positioning device (16) is formed as a single piece, in particular integrally, with the cylindrical annular section (15).

9. The axial flux machine (1) according to claim 7, characterized in that the fifth positioning device (16) is designed as a component (18) separate from the cylindrical annular section (15).

10. The axial flux machine (1) according to any one of the preceding claims, characterized in that the axial flux machine (1) is configured in an I-shaped arrangement.

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