Electric axial flux machine

Abstract

The invention relates to an electric axial flux machine (1), in particular for use within a drive train of a hybrid or fully electrically driven motor vehicle, comprising a stator (2) and a rotor (4) separated from the stator (2) by an air gap (3), wherein the stator (2) is accommodated in a pot-like 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 by a housing cover (7) on the side axially opposite the housing base (6), wherein the housing cover (7) has at least one first positioning means (8) projecting in the axial direction out of the housing cover (7) or projecting in the axial direction into the housing cover (7), which first positioning means co-operates with a corresponding second positioning means (9) on the stator (2) in such a way that the position of the stator (2) is fixed relative to the housing cover (7).

Description

[0001] Electric axial flux machine

[0002] The present invention relates to an electric axial flux machine, in particular for use within a drive train of a hybrid or fully electric motor vehicle, comprising a stator and a rotor separated from the stator by an air gap.

[0003] 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.

[0004] 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 a vehicle axle that includes an electric motor arranged coaxially with a bevel gear differential. Such drive units are also referred to as e-axles or electrically driven drivetrains.

[0005] 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.

[0006] Due to its disc-shaped main components, an axial flux machine is particularly well-suited for applications where a very short electric motor length is essential and where a relatively large motor diameter is still acceptable. When developing such axial flux machines, it is therefore generally advisable to strive for the shortest possible design, while keeping the outer diameter of the axial flux machine no larger than absolutely necessary. Axial flux machines for automotive applications also always have to meet the requirements of low weight, high power density, and low cost.

[0007] It is therefore the object of the invention to provide an electric axial flux machine that is inexpensive to manufacture and easy to assemble.

[0008] This object is achieved by an electric axial flux machine, in particular for use within a drive train of a hybrid or fully electric motor vehicle, comprising a stator and a rotor separated from the stator by an air gap, wherein the stator is accommodated in a pot-like annular housing with a housing base extending in the radial direction, wherein the housing base extends through the air gap between stator and rotor and the housing is closed on the side axially opposite the housing base by a housing cover, wherein the housing cover has at least one first positioning means projecting in the axial direction from the housing cover or at least one first positioning means projecting in the axial direction into the housing cover, which cooperates with a corresponding second positioning means on the stator in such a way thatthat the position of the stator is fixed relative to the housing cover, and / or the housing cover has at least one third positioning means projecting axially from the housing cover or at least one third positioning means projecting axially into the housing cover, which cooperates with a corresponding fourth positioning means on the housing such that the position of the housing relative to the housing cover is fixed.

[0009] This has the advantage that components of the axial flux machine can be positioned directly relative to one another via these components themselves, which allows for shorter tolerance chains and, consequently, more efficient use of installation space. For this purpose, the stator and housing are positioned directly via the corresponding positioning elements, which are designed, for example, as recesses or protrusions on the housing cover. The tolerance chains between the stator and housing cover, as well as between the housing and the stator or housing cover, can be kept as short as possible thanks to this measure. Furthermore, no additional assembly aids are required in the tool, which can also positively impact ease of assembly and manufacturing costs.

[0010] First, the individual elements of the claimed subject matter of the invention are explained in the order in which they appear in the set of claims, and subsequently particularly preferred embodiments of the subject matter of the invention are described.

[0011] The magnetic flux in an electric axial flux machine (AFM), such as an electric drive machine of a motor vehicle designed as an axial flux machine, is directed axially to a direction of rotation of the rotor of the axial flux machine in the air gap between stator and rotor.

[0012] 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.

[0013] In principle, it is also possible that a plurality of rotor-stator

[0014] I-type and / or H-type configurations are 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, 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 with one another and connected to a common rotor shaft or to multiple rotor shafts.

[0015] 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 electrical sheets. Alternatively, the stator body can also be formed from a pressed soft magnetic material, such as the so-called SMC material (Soft Magnetic Compound).

[0016] The stator is housed in a housing. The housing can be a single-piece or multi-piece construction. The housing is particularly preferably made of plastic. The housing can be closed on all sides. It is also possible to provide openings in the housing, for example, to reduce weight or to provide access to a component.

[0017] 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 axial direction. Alternatively, the rotor of an axial flux machine can also have a rotor carrier, which is equipped with magnetic laminations and / or SMC material and with magnetic elements designed as permanent magnets.

[0018] The permanent magnets can preferably be incorporated into the pockets of the rotor laminated core. In this case, a single larger rotor magnet designed as a bar magnet or several smaller permanent magnet elements designed as rotor magnets can be provided per pocket. The rotor preferably has a plurality of rotor bodies. Particularly preferably, the rotor bodies are formed from essentially the same parts, in particular essentially identical. It is most preferred for the rotor bodies to be formed from identical, in particular essentially identical rotor laminations. The rotor bodies are therefore particularly preferably formed from a rotor laminated core, which is composed of a plurality of laminated individual laminations or rotor laminations, generally made of electrical steel sheet, which are layered and packaged one above the other to form a stack, the so-called rotor laminated core.The individual laminations can be held together in the rotor core by gluing, welding, or screwing. A rotor core can also, in particular, contain permanent magnets embedded in the pockets of the rotor core or fixed circumferentially to the rotor core.

[0019] A rotor shaft is a rotatably mounted shaft of an electrical machine to which the rotor or rotor body is non-rotatably coupled.

[0020] 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.

[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 30 kW, preferably greater than 50 kW, and in particular greater than 70 kW. It is further preferred that the electric machine provides speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, and most preferably greater than 12,500 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. It can be provided, in particular, that the electric axial flux machine and the transmission are arranged in a common drive train housing. Particularly preferably, such a drive train housing can also form a connecting structure for the axial flux machine. 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.

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

[0023] According to a further preferred development of the invention, it can also be provided that the first positioning means and / or the third positioning means are each formed as a separate component from the housing cover. Such a separate component can be, for example, a feather key.

[0024] Furthermore, according to a likewise 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 advantageous effect of this embodiment is based on the fact that by integrating a further function into the separate component, a higher degree of system integration can be achieved, which can also contribute to simplified assembly and reduced manufacturing costs. According to another particularly preferred embodiment of the invention, it can be provided that the first positioning means and the third positioning means are designed as a single piece, which can also have a positive impact on manufacturing costs.

[0025] Furthermore, the invention can also be further developed such that the second positioning means is designed as a recess extending axially into the stator. The advantage of this design is that such a recess can be implemented relatively easily in a stator, which can again contribute to cost-effective production of the axial flux machine.

[0026] In a likewise preferred embodiment of the invention, it can also be provided that the housing cover has a cylindrical ring section extending in the axial direction toward the rotor, on which at least one fifth positioning means is located, projecting radially into or out of the cylindrical ring section. This fifth positioning means interacts with a corresponding sixth positioning means on the housing such that the position of the housing relative to the housing cover is fixed. This also provides a manufacturing-technically advantageous variant for positioning the components relative to one another.

[0027] It may also be advantageous to further develop the invention such that the fifth positioning means is formed integrally, in particular monolithically, with the cylinder ring section, which can again provide manufacturing advantages. According to a further preferred embodiment of the subject matter of the invention, however, it may also be provided that the fifth positioning means is formed as a separate component from the cylinder ring section, for example, as a feather key.

[0028] Finally, the invention can also be advantageously implemented in such a way that the axial flux machine is configured in an I-arrangement. The invention will be explained in more detail below with reference to figures, without limiting the general inventive concept.

[0029] It shows:

[0030] Figure 1 shows an electrical axial flux machine in a schematic axial section,

[0031] Figure 2 shows a first embodiment of a stator of an electric axial flux machine in a schematic axial sectional view,

[0032] Figure 3 shows a second embodiment of a stator of an electric axial flux machine in a schematic axial sectional view,

[0033] Figure 4 shows a third embodiment of a stator of an electric axial flux machine in a schematic axial sectional view,

[0034] Figure 5 shows a fourth embodiment of a stator of an electric axial flux machine in a schematic axial sectional view,

[0035] Figure 6 shows a fifth embodiment of a stator of an electric axial flux machine in a schematic axial sectional view,

[0036] Figure 7 shows a sixth embodiment of a stator of an electric axial flux machine in a schematic axial sectional view,

[0037] Figure 8 shows a seventh embodiment of a stator of an electric axial flux machine in a schematic axial sectional view and a stator body in a perspective view,

[0038] Figure 9 shows an eighth embodiment of a stator of an electrical axial flux machine in a schematic axial sectional view, Figure 10 shows a ninth embodiment of a stator of an electrical axial flux machine in a schematic axial sectional and a cross-sectional view,

[0039] Figure 11 shows a tenth embodiment of a stator of an electric axial flux machine in a schematic axial section and a cross-sectional view,

[0040] Figure 12 shows an eleventh embodiment of a stator of an electric axial flux machine in a schematic axial sectional view,

[0041] Figure 13 shows a twelfth embodiment of a stator of an electric axial flux machine in a schematic axial sectional view,

[0042] Figure 14 shows a thirteenth embodiment of a stator of an electric axial flux machine in a schematic axial sectional view,

[0043] Figure 15 shows a fourteenth embodiment of a stator of an electric axial flux machine in a schematic axial sectional view.

[0044] Figure 1 shows an electric axial flux machine 1, in particular for use within a drive train of a hybrid or fully electric motor vehicle, comprising a stator 2 with a stator winding 23 and a rotor 4 separated from the stator 2 by an air gap 3. The axial flux machine 1 is configured in an I arrangement, resulting in a structure of the axial flux machine 1 that is a mirror image of the radial plane of the rotor 4. For reasons of clarity, reference numerals have therefore been omitted for the right-hand stator. It is understood, however, that this is essentially a mirror image of the left-hand stator 2.

[0045] The stator 2 is housed in a pot-shaped annular housing 5 with a

[0046] Radially extending housing base 6, wherein the

[0047] The housing base 6 extends through the air gap 3 between the stator 2 and the rotor 4, and the housing 5 is closed by a housing cover 7 on the side axially opposite the housing base 6. The housing 5 is thus reminiscent of the shape of a donut.

[0048] The housing 5 is sealed against the housing cover 7 via the seal 28 and is axially secured by means of the retaining ring 29.

[0049] The housing cover 7 has at least one first positioning means 8 protruding in the axial direction from the housing cover 7 or at least one first positioning means 8 protruding in the axial direction into the housing cover 7, which cooperates with a corresponding second positioning means 9 on the stator 2 such that the position of the stator 2 relative to the housing cover 7 is fixed. Furthermore, the housing cover 7 can have at least one third positioning means 10 protruding in the axial direction from the housing cover 7 or at least one third positioning means 10 protruding in the axial direction into the housing cover 7, which cooperates with a corresponding fourth positioning means 9 on the housing 5 such that the position of the housing 5 relative to the housing cover 7 is fixed. This results in a series of configuration options, which are explained in more detail below with reference to Figures 2-11.

[0050] Figure 2 shows an embodiment in which the first positioning means 8 and the third positioning means 10 are each formed integrally, in particular monolithically, with the housing cover 7 and protrude axially from the housing cover 7. The positioning means 8, 10 can be formed, for example, by means of caulking. As a result, the positioning means 8, 10 have a pin-like design, wherein the first positioning means 8 engages in a corresponding recess (second positioning means 9) of the stator 2 and the second positioning means 10 engages in a corresponding recess (fourth positioning means 19) of the housing 5 formed on the radially inner circumference of the housing 5. In order to also achieve centering of the components relative to one another, it is recommended to form at least three pin-like positioning means 8, 10 on the circumference of the housing cover 7. If centering is required, for example,over a hundredweight diameter, a pin-like positioning device 8,10 is sufficient for the circumferential positioning of the corresponding component.

[0051] Figure 3 shows an embodiment slightly modified from Figure 2, in which the first positioning means 8 and the third positioning means 10 are designed as a single piece and positioned in the radially inner circumferential region of the housing 5. The single-piece positioning means 8, 10 is also formed monolithically from the housing cover 7 by means of caulking.

[0052] A modification of the solution known from Figure 3 is shown in Figure 4. Here, the first positioning means 8 and the third positioning means 10 are formed together, but as a separate component 12 from the housing cover 7. The separate component 12 is a key and is positioned in the radially inner region of the housing 5. Positioning in the radially outer region of the housing 5 is also possible, as shown in Figure 6.

[0053] As can be seen in Figure 7, in 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 current to the stator winding 23.

[0054] Figure 5 shows a slight modification of the embodiment already known from Figure 2. Here, however, the third positioning means 10 is designed as a recess into which a separate component 12 designed as a key engages and effects the positioning of the housing 5 relative to the housing cover 7. It is of course also possible for the separate component 12 to be formed integrally with the housing 5 and then engage as a pin-like positioning means 19 into the corresponding recess of the housing cover 7.

[0055] Figure 8 shows an alternative design in which the second positioning means 9 is designed as a recess 11 extending axially into the stator 2. On the side of the stator 2 facing the housing cover 7, a plurality of such recesses 11 can extend radially through the annular disk-like stator yoke 21 of the stator body 20, which function as cooling channels 24. The stator body 20 also has stator teeth 22 extending axially from the stator yoke 21. The cooling channels 24 can therefore now be used to provide a recess 11 in the stator 2, into which the first positioning means 8 engages. The recess 11 then forms the second positioning means 9.In the case of a stator 2 wound from a sheet metal strip, it makes sense to compensate for the position between the housing cover 7 and the stator 2 as far radially inward as possible, since the wound stator 2 has the highest accuracy in this area.

[0056] Through a cooling fluid inlet 26, the cooling fluid 25 can be passed through the housing cover 7 and supplied to the cooling channels 24. The cooling fluid 25 then leaves the stator area again through the outlet opening 27 in the radially upper area of ​​the housing 5.

[0057] The embodiment of Figure 9 essentially corresponds to that of Figure 8, except that here the cooling channel is molded into the housing cover 7. A pin-like positioning means 9 for positioning is then provided on the stator 2, which engages in the cooling channel of the housing cover 7. The cooling channel 24 thus represents the first positioning means 8 of the housing cover 7.

[0058] Figures 10-11 show two embodiments in which the housing cover 7 has a cylindrical ring section 15 extending in the axial direction towards the rotor 4, on which at least one fifth positioning means 16 is formed, projecting in the radial direction into the cylindrical ring section 15 or extending out of the cylindrical ring section 15, which cooperates with a corresponding sixth positioning means 17 on the housing 5 such that the position of the housing 5 relative to the housing cover 7 is fixed. Figure 10 shows an embodiment in which the fifth positioning means 16 is formed integrally, in particular monolithically, with the cylindrical ring section 15. The positioning of the housing 5 can therefore take place, for example, via a spline (positive fit) on the cylindrical ring section 15.As can be seen from the figures, the axial flow machine 1 in the embodiment shown has a housing cover 7 and a hub connected to the housing cover 7 via a welded joint, which forms the cylindrical ring section 15. If the housing cover 7 is centered over a diameter, one tooth-like positioning means 16 is sufficient to maintain the circumferential position, as shown in Figure 10. Otherwise, at least three tooth-like positioning means 16 are required to additionally center the housing 5.

[0059] In the embodiment of Figure 11, the fifth positioning means 16 is designed as a component 18 separate from the cylinder ring section 15, for example as a feather key.

[0060] Figures 12-15 show further embodiments of the invention in which the housing base 6 and / or the housing cover 7 are also positioned above the stator 2. Otherwise, these embodiments correspond to those known from Figures 2-7.

[0061] 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.

[0062] List of reference symbols

[0063] 1 axial flux machine

[0064] 2 Stator

[0065] 3 Air gap

[0066] 4 Rotor

[0067] 5 housings

[0068] 6 Case back

[0069] 7 Housing cover

[0070] 8 positioning aids

[0071] 9 Positioning tools

[0072] 10 positioning tools

[0073] 11 Deepening

[0074] 12 components

[0075] 13 ladders

[0076] 14 Implementation

[0077] 15 Cylinder ring section

[0078] 16 positioning devices

[0079] 17 Positioning devices

[0080] 18 component

[0081] 19 positioning aids

[0082] 20 stator bodies

[0083] 21 Stator yoke

[0084] 22 stator teeth

[0085] 23 Stator winding

[0086] 24 cooling channels

[0087] 25 Cooling fluid

[0088] 26 Cooling fluid inlet

[0089] 27 Cooling fluid outlet

[0090] 28 Sealing ring

[0091] 29 Retaining ring

Claims

Claims 1. An electric axial flux machine (1), particularly for use within a drive train of a hybrid or fully electric motor vehicle, 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 accommodated in a pot-shaped, annular housing (5) with 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 by a housing cover (7) on the side axially opposite the housing base (6), wherein the housing cover (7) has at least one first positioning means (8) projecting axially out of the housing cover (7) or at least one first positioning means (8) projecting axially into the housing cover (7).which cooperates with a corresponding second positioning means (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 means (10) projecting axially out of the housing cover (7) or at least one third positioning means (10) projecting axially into the housing cover (7), which cooperates with a corresponding fourth positioning means (19) on the housing (5) such that the position of the housing (5) relative to the housing cover (7) is fixed.

2. Axial flow machine (1) according to claim 1, characterized in that the first positioning means (8) and / or the third positioning means (10) is formed integrally, in particular monolithically, with the housing cover (7).

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

4. 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. Axial flow machine (1) according to one of the preceding claims, characterized in that the first positioning means (8) and the third positioning means (10) are designed in one piece.

6. Axial flow machine (1) according to one of the preceding claims, characterized in that the second positioning means (9) is designed as a recess (11) extending axially into the stator (2).

7. Axial flow machine (1) according to one of the preceding claims, characterized in that the housing cover (7) has a cylindrical ring section (15) extending in the axial direction towards the rotor (4), on which at least one fifth positioning means (16) protruding in the radial direction into the cylindrical ring section (15) or extending out of the cylindrical ring section (15) is provided, which cooperates with a corresponding sixth positioning means (17) on the housing (5) in such a way that the position of the housing (5) relative to the housing cover (7) is fixed.

8. Axial flow machine (1) according to claim 7, characterized in that the fifth positioning means (16) is formed integrally, in particular monolithically, with the cylinder ring section (15).

9. Axial flow machine (1) according to claim 7, characterized in that the fifth positioning means (16) is designed as a component (18) separate from the cylinder ring section (15).

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

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