Stator assembly and method for producing a stator receiving area

Abstract

The invention relates to a stator assembly (1) for an electric axial flux machine (2), comprising a stator (3) and a stator receiving area (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 axially, wherein the stator receiving area (4) has contact elements (7) which are monolithically formed together with the stator receiving area (4) and which protrude axially therefrom and against which the stator yoke (5) rests axially, wherein each of the contact elements (7) has a first contact section (8) and a second contact section (9) arranged at a distance thereto, said contact sections (8, 9) resting against the stator yoke (5).

Description

[0001] Stator arrangement and method for producing a stator holder

[0002] 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, wherein the stator has a disk-shaped stator yoke from which a plurality of stator teeth extend axially. The invention further relates to a method for producing a stator receptacle.

[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 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 arguably represents the closest state of the art. This article describes a drive unit for one axle of a vehicle which comprises an electric motor which is arranged concentrically and coaxially to a bevel gear differential, with a switchable 2-speed planetary gear set being arranged in the power train between the electric motor and bevel gear differential, which is also positioned coaxially to 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.

[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] 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.

[0007] This object is achieved by 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 receptacle has contact elements formed monolithically with the stator receptacle, axially protruding therefrom, against which the stator yoke bears axially, wherein the contact elements each have a first contact section and a second contact section spaced therefrom, wherein the contact sections bear against the stator yoke.

[0008] One advantage of this stator assembly is that the stator mount with its monolithically formed contact elements enables very stable and precise stator mounting. Furthermore, the monolithic design of the contact elements simplifies the manufacturing of the stator assembly, enabling greater precision and cost efficiency.

[0009] 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 F-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.

[0010] In principle, it is also conceivable that the axial flux machine consists of exactly one stator and exactly one rotor.

[0011] 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.

[0012] 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).

[0013] 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.

[0014] A rotor shaft is a rotatably mounted shaft of an electrical machine to which the rotor or rotor body is rotationally fixedly coupled.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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 that 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 electronic components that are designed to control or regulate a current. This particularly preferably involves one or more power switches, e.g.

[0022] Power transistors. The power electronics particularly preferably have more than two, particularly preferably three, separate phases or current paths, each with at least one dedicated power electronics component. The power electronics are preferably designed to control or regulate a power 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] The stator receptacle can be plate-shaped, at least in sections. Particularly preferably, the stator receptacle is designed as a shell, in which a plate-shaped base is enclosed by a rim extending from it. Most preferably, the stator receptacle is formed from a sheet metal. In principle, it would also be possible to form the stator receptacle from a plastic material. Advantageous embodiments of the invention

[0027] According to an advantageous embodiment of the invention, the contact elements can be provided so that they extend radially along the stator receptacle, spaced apart in the circumferential direction. The advantage of this embodiment is that it allows for a particularly mechanically stable contact between the contact elements and the stator yoke.

[0028] Particularly preferably, the contact elements are arranged equidistantly in the circumferential direction. Furthermore, it may be preferable for the number of contact elements to correspond to the number of stator teeth. In this context, it is further preferable for each stator tooth to be assigned a contact element.

[0029] According to a further preferred development of the invention, it can also be provided that the contact elements are arranged radially aligned with one another. In this case, several separate contact elements are aligned radially aligned and spaced radially from one another. This allows the contact area between the contact elements and the stator yoke to be reduced, which in turn allows, for example, a larger area of ​​the stator yoke to be overflown by a cooling fluid. This allows stator cooling to be optimized.

[0030] Furthermore, according to a similarly advantageous embodiment of the invention, it can be provided that a plurality of the contact elements are arranged on a common pitch circle. The advantageous effect of this embodiment is that it allows for a more uniform contact of the stator yoke with the contact elements.

[0031] According to a further particularly preferred embodiment of the invention, it can be provided that the contact sections of a contact element are spaced from one another by a concave or convex contour. Furthermore, the invention can also be further developed such that openings extending into the stator yoke in the axial direction are provided, wherein the contact sections each extend into a corresponding opening and bear against the corresponding opening in the circumferential direction and / or axial direction. The advantage of this embodiment is that it allows both a radial and circumferential fixing of the stator yoke relative to the stator receptacle. It is also conceivable for the stator receptacle to be fixed axially relative to the stator yoke, for example by the contact sections abutting axially in the corresponding opening.

[0032] In a likewise preferred embodiment of the invention, it can also be provided that a channel through which a fluid can flow is formed between the stator yoke and one of the contact elements, which can improve the cooling of the stator.

[0033] It may also be advantageous to further develop the invention in such a way that the convex contour of the contact element engages in an opening assigned to it.

[0034] The object of the invention can also be achieved by a method for producing a stator holder comprising the following steps:

[0035] • Providing a die having a convex section extending in cross-section between two parallel grooves,

[0036] • Providing a punch with a concave section which runs in cross-section between two parallel webs,

[0037] • Provision of a stator holder formed from a sheet metal

[0038] Inserting the stator holder between the die and the punch,

[0039] Moving the punch against the die or vice versa. Finally, the object of the invention can also be achieved by a method for producing a stator holder comprising the following steps:

[0040] • Providing a die with a groove having a shoulder on each of its side walls along its longitudinal extent,

[0041] • Provision of a stamp,

[0042] • Provision of a stator holder formed from a sheet metal

[0043] • Inserting the stator holder between the die and the punch,

[0044] • Moving the punch against the die or vice versa.

[0045] The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

[0046] It shows:

[0047] Figure 1 shows an axial flow machine in a schematic axial section,

[0048] Figure 2 shows a stator arrangement of an axial flow machine in an exploded view,

[0049] Figure 3 shows a stator arrangement of an axial flux machine in a perspective view,

[0050] Figure 4 shows three different embodiments of a stator holder in a perspective view,

[0051] Figure 5 shows a stator arrangement in a schematic sectional view, Figure 6 shows five different embodiments of stator arrangements, each in a schematic sectional view,

[0052] Figure 7 shows an embodiment of a stator holder in a perspective view,

[0053] Figure 8 shows a stator arrangement with the stator holder known from Figure 7 in a perspective axial section,

[0054] Figure 9 shows a detailed view of a contact element of the stator holder known from Figure 7,

[0055] Figure 10 shows two embodiments of dies and punches for forming a stator holder in two schematic sectional views each,

[0056] Figure 11 shows a motor vehicle with an electric drive train in a schematic representation.

[0057] Figure 1 shows an axial flux machine 2 in an 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 outlined in Figure 11, such an axial flux machine 2 can be installed in a drive train 43 of a motor vehicle 44.

[0058] Figures 2-3 show 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. The stator receptacle 4 has contact elements 7 which are formed monolithically with the stator receptacle 4 and project axially therefrom, and against which the stator yoke 5 axially rests. The contact elements 7 each have a first contact section 8 and a second contact section 9 spaced therefrom, wherein the contact sections 8, 9 rest against the stator yoke 5, which can be clearly seen when viewed in conjunction with Figure 5. In the example shown, the stator receptacle 4 is formed from sheet metal. In principle, it would also be possible to form the stator receptacle 4 from a plastic.The contact elements 7 themselves are formed by means of a forming process in such a way that they are manufactured very precisely in the area of ​​the contact sections 8,9.

[0059] As can be seen from illustration a of Figure 4, the contact elements 7 extend circumferentially spaced in the radial direction on the stator holder 4. The contact elements 7 are therefore essentially rod-shaped.

[0060] The radial alignment of the support elements 7 allows the stator 3 to be supported in its radial extension. It is also possible to interrupt this radial extension of the support elements 7 in order to reduce the forming volume. At least three support elements 7 should be molded in, distributed around the circumference, for supporting the stator yoke 5.

[0061] Figure b of Figure 4 shows a correspondingly alternative embodiment of the contact elements 7, in which a plurality of the contact elements 7 are arranged radially aligned with one another and arranged on two pitch circles 11. Figure c of Figure 4 shows a further embodiment of the stator holder 4, in which the contact elements 7 are positioned on a total of three concentrically extending pitch circles 11.

[0062] The illustrations ae of Figure 6 further show that the contact sections 8,9 of a contact element 7 are spaced from each other by a concave or convex contour 10.

[0063] As can be seen in Figures a, b, d, and e, openings 12 extending axially into the stator yoke 5 are provided in the stator yoke 5, with the contact sections 8, 9 each extending into a corresponding opening 12 and resting in the circumferential direction and / or axial direction in the corresponding opening 12. Thus, a channel 13 through which a fluid can flow can be formed between the stator yoke 5 and one of the contact elements 7.

[0064] In the embodiments of Figures d, e, the convex contour 10 of the contact element 7 engages in an opening 12 assigned to it.

[0065] Figures 7-9 show an embodiment of the stator arrangement 1 in which the stator receptacle 4, shaped as a housing cover, was embossed / pushed through on the back with a flat punch 23, thus forming the contact elements 7. In this case, the stator yoke 5 serves as a die 20 for forming the contact elements 7 in a corresponding forming process. In the area of ​​the opening 12 on the stator yoke 5, which is designed as a cooling channel, the material of the stator receptacle 4 is pushed on during forming in order to achieve corresponding volume compensation. The opening 12 has a shoulder 15 on both sides in the circumferential direction. The stator 3 will later sit on the precise lateral flanks of the contact sections 8, 9. The back of the stator receptacle 4, shaped as a housing cover, could be completely turned over in order to reduce the axial height of the axial flux machine.

[0066] The volume defined by contour 10 in the central region of the contact element 7 is thus located in the area of ​​the opening 12 of the stator 3, which is designed as a cooling channel, and can be used as a compensation area during forming, for example, by stamping the contact elements 7. This reduces the force during forming and, as a result, results in improvements in the overall flatness of the formed sheet metal component. Figure 8 also shows the stator teeth 6 wound with the stator winding 14.

[0067] With reference to illustration a of Figure 10, a first possible method for producing a stator holder 4 can now be explained in more detail, comprising the following steps: First, a die 20 is provided, with a convex section 21 which runs in cross section between two parallel grooves 22, and a punch 23 is provided with a concave section 24 which runs in cross section between two parallel webs 25.

[0068] Then, the stator holder 4 formed from a sheet metal is placed between the die 20 and the punch 23 and the punch 23 is displaced against the die 20 or vice versa.

[0069] In illustration b of Figure 10, a further method for producing a stator holder 4 is shown, which is designed as follows.

[0070] First, a die 20 with a groove 26, which has a shoulder 28 on each of its side walls 27 along its longitudinal extent, and a punch 23 is provided.

[0071] Then, the stator holder 4 formed from a sheet metal is positioned between the die 20 and the punch 23 and subsequently the punch 23 is offset against the die 20 or vice versa.

[0072] In both versions, the punch 23 is shaped so that it precisely pushes or stamps the material against the die 20 on the lateral flanks. The central recessed area (section 24 in Figure a, groove 26 in Figure 1) serves as a compensating area during stamping. Excess material can flow into the central area (section 24 in Figure a, groove 26 in Figure 1).

[0073] 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.

[0074] List of reference symbols

[0075] 1 Stator arrangement

[0076] 2 axial flux machine

[0077] 3 Stator

[0078] 4 Stator holder

[0079] 5 Stator yoke

[0080] 6 stator teeth

[0081] 7 investment elements

[0082] 8 Plant section

[0083] 9 Plant section

[0084] 10 Contour

[0085] 11 pitch circle

[0086] 12 openings

[0087] 13 Channel

[0088] 14 Stator winding

[0089] 15 paragraph

[0090] 20 die

[0091] Section 21

[0092] 22 grooves

[0093] 23 stamps

[0094] Section 24

[0095] 25 bridges

[0096] 26 grooves

[0097] 27 side walls

[0098] 28 paragraph

[0099] 41 Rotor

[0100] 42 Rotor shaft

[0101] 43 Drivetrain

[0102] 44 Motor vehicle

Claims

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, characterized in that the stator receptacle (4) has contact elements (7) which are formed monolithically with the stator receptacle (4) and project axially therefrom, against which the stator yoke (5) bears axially, wherein the contact elements (7) each have a first contact section (8) and a second contact section (9) spaced therefrom, wherein the contact sections (8, 9) bear against the stator yoke (5).

2. Stator arrangement (1) according to claim 1, characterized in that the contact elements (7) extend in the circumferential direction at a distance from one another in the radial direction on the stator holder (4).

3. Stator arrangement (1) according to claim 1 or 2, characterized in that the contact elements (7) are arranged in alignment with one another in the radial direction.

4. Stator arrangement (1) according to claim 3, characterized in that a plurality of the contact elements (7) are arranged on a common partial circle (11).

5. Stator arrangement (1) according to one of the preceding claims, characterized in that the contact sections (8, 9) of a contact element (7) are spaced from one another by a concave or convex contour (10).

6. Stator arrangement (1) according to one of the preceding claims, characterized in that openings (12) extending in the axial direction into the stator yoke (5) are provided in the stator yoke (5), wherein the contact sections (8, 9) each extend into a corresponding opening (12) and bear against the corresponding opening (12) in the circumferential direction and / or axial direction.

7. Stator arrangement (1) according to one of the preceding claims, characterized in that a channel (13) through which a fluid can flow is formed between the stator yoke (5) and one of the contact elements (7).

8. Stator arrangement (1) according to one of the preceding claims 6-7, characterized in that the convex contour (10) of the contact element (7) engages in an opening (12) assigned to it.

9. Method for producing a stator holder (4) comprising the following steps: Providing a die (20) having a convex portion (21) extending in cross-section between two parallel grooves (22), Providing a punch (23) with a concave section (24) which runs in cross section between two parallel webs (25), • Provision of a stator holder formed from a sheet metal (4) • Insert the stator holder between the die (20) and the punch (23), • Moving the punch (23) against the die (20) or vice versa.

10. Method for producing a stator holder (4) comprising the following steps: • Providing a die (20) with a groove (26) which has a shoulder (28) along its longitudinal extent on its side walls (27), • Provision of a stamp (23), • Provision of a stator holder formed from a sheet metal (4) • Insert the stator holder between the die (20) and the punch (23), Moving the punch (23) against the die (20) or vice versa.

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