Electric axial flux machine

Abstract

Electric axial flux machine (1) comprising: a stator (2), a disk-shaped first stator body (5) and a disk-shaped second stator body (6) axially spaced from it, and a rotor (3) rotatable relative to the stator (2) with a disk-shaped rotor body (35) arranged non-rotatably on a rotor shaft (4), which is arranged axially between the first stator body (5) and the second stator body (6), wherein a mechanical air gap adjustment (7) is provided in a torque flow between the first stator body (5) and a stator flange (40) and / or between the second stator body (6) and the stator flange (40), to displace the first stator body (5) and / or the second stator body (6) in the axial direction to adjust at least one air gap (L1, L2) between one of the stator bodies (5,6) and the rotor body (35), In the torque flow between the first stator body (5) and the stator flange (40) a first spring element (8) is arranged, which has a first connection section (9) through which the first spring element (8) is coupled in a tensile force-transmitting manner to a first intermediate ring (10) which is rotationally fixed to the stator flange (40), while a second connection section (33) of the first spring element (8) is connected in a tensile force-transmitting manner to the first stator body (5), and the first spring element (8) is configured such that a change in the axial extension (11) of the first spring element (8) can be effected by a tensile force load. In the torque flow between the first stator body (5) and the stator flange (40), a second spring element (12) is arranged, which has a first connection section (13) through which the second spring element (12) is coupled in a tensile force-transmitting manner to a second intermediate ring (14) which is rotationally fixed to the stator flange (40), while a second connection section (15) of the second spring element (12) is connected in a tensile force-transmitting manner to the first stator body (5), and the second spring element (12) is configured such that a change in the axial extension (16) of the second spring element (12) can be effected by a tensile force load, and the first intermediate ring (10) and the second intermediate ring (14) are configured such that in a first torque direction of the first stator body (5) a torque can only be transmitted from the first stator body (5) via the first intermediate ring (10) to the stator flange (40), while in a second torque direction of the first stator body (5) a torque can only be transmitted from the first stator body (5) via the second intermediate ring (14) to the stator flange (40).

Description

[0001] The present invention relates to an electric axial flux machine, comprising a stator and a rotor rotatable relative to the stator, with a disk-shaped rotor body arranged non-rotatably on a rotor shaft, and with a disk-shaped first stator body and a disk-shaped second stator body axially spaced therefrom, wherein the rotor body is arranged axially between the first stator body and the second stator body, wherein in the torque flux between the first stator body and a stator flange and / or between the second stator body and the stator flange, a mechanical air gap adjustment is set up to displace the first stator body and / or the second stator body in the axial direction to adjust at least one air gap between one of the stator bodies and the rotor body.

[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] Axial flux machines are already well known in the state of the art.

[0006] EP 2 985 893 A1 discloses an electric axial flux machine with a stator and a rotor, wherein the stator comprises at least two stator segments, and wherein the rotor is connected to a rotor shaft. The rotor and / or the rotor shaft are rotatably mounted in a bearing, and the stator segments are arranged immovably relative to the bearing in the direction of rotation of the rotor. At least one of the stator segments is arranged movable relative to the bearing in the axial or radial direction in order to adjust the width of the air gap between the rotor and the stator segments.

[0007] Furthermore, DE 10 2019 131 198 A1 describes a modular axial flux motor for automated guided vehicles, comprising at least one disc-shaped stator and at least one disc-shaped rotor rotatable relative to the stator. The rotor and stator are arranged axially adjacent to one another. The stator comprises electrical coils. The rotor has at least one permanent magnet with alternating poles. The rotor shaft is mounted in a conventional manner in housing side walls or the like via rolling bearings. The rolling bearings are usually preloaded in the axial direction by spring means so that the rolling element balls roll under force and in contact with one another in the raceways between the inner ring and outer ring.

[0008] DE 10 2020 114 855 B3 further discloses an electrical machine designed as a permanent-magnet synchronous machine, comprising a rotor with at least one rotor body arranged on a rotor shaft and a stator, as well as an adjusting device designed to generate the axial relative movement between the at least one rotor body and the stator in the direction of the stator as a function of a torque occurring between the rotor shaft and the at least one rotor body. The at least one adjusting device has a first adjusting element, a second adjusting element, and at least one rolling element arranged between the first adjusting element and the second adjusting element. The first adjusting element is arranged so as to be axially displaceable and rotatable to a limited extent on the axially immovable rotor shaft, and the second adjusting element is connected to the rotor shaft so as to be rotationally and non-displaceably fixed.The adjusting elements are designed in such a way that in the event of a rotation of the first adjusting element against the second adjusting element or vice versa, the at least one rotor body is displaced axially on the rotor shaft against the spring force.

[0009] An electric machine with air gap adjustment is also described in US 2009 / 0134723 A1. This electric motor device comprises a first drive element having a plurality of permanent magnets; a second drive element having a plurality of electromagnetic coils; and a distance controller that displaces at least one of the first drive element and the second drive element, thereby changing the size of a gap formed between the first drive element and the second drive element.

[0010] From US 2011 / 0 074 238 A1, an electric axial flux machine is known which has a stator, a disk-shaped first stator body, and a rotor rotatable relative to the stator, with a disk-shaped rotor body arranged non-rotatably on a rotor shaft. In a torque flow between the first stator body and a stator flange, a mechanical air gap adjustment is configured to displace the first stator body in the axial direction to adjust at least one air gap between the first stator body and the rotor body. A first spring element is arranged in the torque flow between the rotor body and the stator flange, which is configured such that a change in the axial extent of the first spring element can be effected by a tensile force load.

[0011] It is an object of the present invention to provide an axial flux machine in I-arrangement which is improved with regard to torque-dependent field amplification.

[0012] This object is achieved by an electric axial flux machine, comprising a stator and a rotor rotatable relative to the stator, with a disk-shaped rotor body arranged non-rotatably on a rotor shaft, and with a disk-shaped first stator body and a disk-shaped second stator body axially spaced therefrom, wherein the rotor body is arranged axially between the first stator body and the second stator body, wherein in the torque flow between the first stator body and a stator flange and / or between the second stator body and the stator flange, a mechanical air gap adjustment is arranged to displace the first stator body and / or the second stator body in the axial direction to adjust at least one air gap between one of the stator bodies and the rotor body, wherein a first spring element is arranged in the torque flow between the first stator body and the stator flange,wherein the first spring element has a first connection section, through which the first spring element is coupled to a first intermediate ring, which is connected in a rotationally fixed manner to the stator flange, in a tensile force-transmitting manner, while a second connection section of the first spring element is connected to the first stator body in a tensile force-transmitting manner, and the first spring element is configured such that a change in the axial extent of the first spring element can be effected by a tensile force load, and a second spring element is arranged in the torque flow between the first stator body and the stator flange, wherein the second spring element has a first connection section, through which the second spring element is coupled to a second intermediate ring, which is connected in a rotationally fixed manner to the stator flange, in a tensile force-transmitting manner, while a second connection section of the second spring element is connected to the first stator body in a tensile force-transmitting manner,and the second spring element is configured such that a change in the axial extent of the second spring element can be effected by a tensile force load, and the first intermediate ring and the second intermediate ring are configured such that in a first torque direction of the first stator body, a torque can only be transmitted from the first stator body via the first intermediate ring to the stator flange, while in a second torque direction of the first stator body, a torque can only be transmitted from the first stator body via the second intermediate ring to the stator flange.

[0013] This provides the advantage of a structurally simple and cost-effective air gap adjustment for an axial flux machine. Furthermore, the use of spring elements instead of rolling elements, for example, ensures high wear resistance and a long service life for the air gap adjustment.

[0014] 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.

[0015] 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.

[0016] 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 configured in an I-arrangement.

[0017] 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.

[0018] 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).

[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 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The control unit can particularly preferably comprise a power electronics module for supplying current to the stator or rotor. A power electronics module 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 module contains power electronics or 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 are preferably designed to control or regulate a power with a peak power, preferably continuous power, of at least 10 W, preferably at least 100 W, particularly preferably at least 1000 W per phase.

[0028] The electric 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 rotational speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, and most particularly preferably greater than 12,500 rpm.

[0029] The electric axial flux machine can 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.

[0030] The electric axial flux machine can particularly preferably also be provided for use in a hybrid module. In a hybrid module, components and functional elements of a hybridized drive train can be spatially and / or structurally combined and preconfigured, so that a hybrid module can be integrated into a motor vehicle's drive train in a particularly simple manner. In particular, an axial flux machine and a clutch system, in particular with a separating clutch for coupling the axial flux machine into and / or disengaging the axial flux machine from the drive train, can be present in a hybrid module.

[0031] Advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically expedient manner and can define further embodiments of the invention. Furthermore, the features specified in the claims are further specified and explained in the description, where further preferred embodiments of the invention are presented.

[0032] According to an advantageous embodiment of the invention, it can be provided that a third spring element is arranged in the torque flow between the second stator body and the stator flange, wherein the third spring element has a first connection section through which the third spring element is coupled to a third intermediate ring, which is connected in a rotationally fixed manner to the stator flange, in a tensile force-transmitting manner, while a second connection section of the third spring element is connected to the second stator body in a tensile force-transmitting manner, and the third spring element is configured such that a change in the axial extent of the third spring element can be effected by a tensile force load, and a fourth spring element is arranged in the torque flow between the second stator body and the stator flange, wherein the fourth spring element has a first connection section through which the fourth spring element is coupled to a fourth intermediate ring,which is connected in a rotationally fixed manner to the stator flange, while a second connection section of the fourth spring element is connected to the second stator body in a tensile force-transmitting manner, and the fourth spring element is configured such that a change in the axial extent of the fourth spring element can be effected by a tensile force load, and the third intermediate ring and the fourth intermediate ring are configured such that in a first torque direction of the second stator body, a torque can only be transmitted from the second stator body via the third intermediate ring to the stator flange, while in a second torque direction of the second stator body, a torque can only be transmitted from the second stator body via the fourth intermediate ring to the stator flange.

[0033] The advantage of this design is that in the I-arrangement of the axial flux machine both stator bodies can be mechanically adjusted axially against the rotor, which enables improved control of the operating states of the corresponding axial flux machine.

[0034] According to a further preferred development of the invention, it can also be provided that the first spring element and / or the second spring element and / or the third spring element and / or the fourth spring element comprise / comprise at least one leaf spring. Leaf springs have proven particularly advantageous in connection with the invention, as they operate wear- and friction-free and do not allow tilting.

[0035] Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the first spring element and / or the second spring element and / or the third spring element and / or the fourth spring element comprise / comprises a plurality of leaf springs, which are arranged circumferentially distributed between the corresponding intermediate rings and stator bodies. The advantageous effect of this embodiment is based on the fact that a uniform air gap adjustment can be achieved over the circumference, even without the risk of the corresponding stator body tilting.

[0036] According to another particularly preferred embodiment of the invention, the first spring element, the second spring element, the third spring element, and the fourth spring element can be constructed from essentially identical parts, thereby reducing the corresponding component variance and complexity in the axial flux machine and thus lowering manufacturing costs. Furthermore, assembly reliability is increased because inadvertent interchange of different spring elements is impossible.

[0037] Furthermore, the invention can also be further developed in such a way that the first spring element has a spring constant different from the second spring element and / or the third spring element has a spring constant different from the fourth spring element.

[0038] The angle of attack of the first spring element may also be different from the angle of attack of the second spring element and / or the angle of attack of the third spring element may be different from the angle of attack of the fourth spring element.

[0039] For example, the air gap adjustment can exhibit different operating behavior with regard to the adjustment of one or both air gaps in motor operation of the axial flux machine than in generator operation. The different adjustment torques prevent the machine from switching to the small air gap too early in an active short circuit and thus braking very sharply. A further advantage of this design can be that the air gap adjustment of the axial flux machine can exhibit different operating behavior when adjusting the air gap for different directions of rotation of the rotor. For example, the air gap adjustment can exhibit different operating behavior with regard to the adjustment of one or both air gaps in motor operation of the axial flux machine than in generator operation.

[0040] In a likewise preferred embodiment of the invention, it can also be provided that the spring constant of the first spring element substantially corresponds to the spring constant of the third spring element and / or the spring constant of the second spring element substantially corresponds to the spring constant of the fourth spring element. This makes it possible to achieve a substantially identical operating behavior of the air gap adjustment at both air gaps for both generator and motor operation of the axial flux machine.

[0041] The angle of attack of the first spring element and the angle of attack of the second spring element can also be substantially identical, and / or the angle of attack of the third spring element and the angle of attack of the fourth spring element can be substantially identical. This also makes it possible to achieve a substantially identical operating behavior of the air gap adjustment at both air gaps for both generator and motor operation of the axial flux machine.

[0042] It may also be advantageous to further develop the invention such that a first compensation spring element applies a spring force directed axially toward the rotor to the first stator body and / or a second compensation spring element applies a spring force directed axially toward the rotor to the second stator body. The advantage of this is that the spring force required to actuate the air gap adjustment can be reduced and the corresponding spring elements in the air gap adjustment can be dimensioned more compactly. If no compensation is present, the angle of attack of the spring elements designed as leaf springs would have to be very steep so that a large amount of axial force can be generated from the low torque.

[0043] According to a further preferred embodiment of the subject matter of the invention, it can be provided that the axial movement of the first stator body toward the rotor is limited by a mechanical stop and / or the axial movement of the second stator body toward the rotor is limited by a mechanical stop. This can ensure that the rotor is mechanically prevented from inadvertently contacting the stator during operation of the electric axial flux machine.

[0044] Finally, the invention can also be advantageously designed such that the first intermediate ring and the second intermediate ring are arranged in a common radial plane and / or the third intermediate ring and the fourth intermediate ring are arranged in a common radial plane.

[0045] The advantage that results from this is that the air gap adjustment in the axial direction can be designed to be particularly compact

[0046] The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

[0047] It shows: Fig. 1 an embodiment of an axial flow machine according to the invention in an axial sectional view, Fig. 2 an air gap adjustment of the axial flow machine in a schematic axial sectional view and in two different perspective views, each in a non-torqued operating state, Fig. 3 an air gap adjustment of the axial flow machine in a schematic axial sectional view and in two different perspective views, each in an operating state subjected to torque in a first direction, Fig. 4 an air gap adjustment of the axial flow machine in a schematic axial sectional view and in two different perspective views, each in an operating state subjected to torque in a second direction, Fig. 5 an axial force-air gap width diagram with an axial flow machine shown in axial section in a first operating state, and Fig. 6 an axial force-air gap width diagram with an axial flux machine shown in axial section in a second operating state.

[0048] The Fig. 1 shows an electric axial flux machine 1, comprising a stator 2 and a rotor 3 rotatable relative to the stator 2, with a disk-shaped rotor body 35 arranged non-rotatably on a rotor shaft 4. The stator 2 has a disk-shaped first stator body 5 and a disk-shaped second stator body 6 axially spaced therefrom, wherein the rotor body 35 is arranged axially between the first stator body 5 and the second stator body 6. The axial flux machine 1 shown is thus designed in an I-arrangement.

[0049] In the torque flow between the first stator body 5 and a stator flange 40 and between the second stator body 6 and the stator flange 40, a mechanical air gap adjustment 7 is configured to displace the first stator body 5 and the second stator body 6 in the axial direction to adjust at least one air gap L1, L2 between one of the stator bodies 5, 6 and the rotor body 35.

[0050] The corresponding mechanical mechanism is determined by the Fig. 2-4 will now be explained in more detail. A first spring element 8 is arranged in the torque flow between the first stator body 5 and the stator flange 40. The first spring element 8 has a first connection section 9, through which the first spring element 8 is coupled to a first intermediate ring 10, which is connected in a rotationally fixed manner to the stator flange 40, in a tensile force-transmitting manner, while a second connection section 33 of the first spring element 8 is connected to the first stator body 5 in a tensile force-transmitting manner. The first spring element 8 is configured such that a change in the axial extent 11 of the first spring element 8 can be effected by a tensile force load.

[0051] Furthermore, a second spring element 12 is arranged in the torque flow between the first stator body 5 and the stator flange 40. The second spring element 12 has a first connection section 13 through which the second spring element 12 is coupled to a second intermediate ring 14, which is connected in a rotationally fixed manner to the stator flange 40, in a tensile force-transmitting manner, while a second connection section 15 of the second spring element 12 is connected to the first stator body 5 in a tensile force-transmitting manner. Here, too, the second spring element 12 is configured such that a change in the axial extent 16 of the second spring element 12 can be effected by a tensile force load.

[0052] In order to always only allow a tensile load in a defined direction of rotation, the first intermediate ring 10 and the second intermediate ring 14 are configured such that in a first torque direction of the first stator body 5, a torque can only be transmitted from the first stator body 5 via the first intermediate ring 10 to the stator flange 40, while in a second torque direction of the first stator body 5, a torque can only be transmitted from the first stator body 5 via the second intermediate ring 14 to the stator flange 40.

[0053] From the Fig. 2 further shows that a third spring element 17 is arranged in the torque flow between the second stator body 6 and the stator flange 40. The third spring element 17 has a first connection section 18 through which the third spring element 17 is coupled to a third intermediate ring 19, which is connected in a rotationally fixed manner to the stator flange 40, in a tensile force-transmitting manner, while a second connection section 20 of the third spring element 17 is connected to the second stator body 6 in a tensile force-transmitting manner. The third spring element 17 is also configured such that a change in the axial extent 21 of the third spring element 17 can be effected by a tensile force load.

[0054] Finally, a fourth spring element 22 is also arranged in the torque flow between the second stator body 6 and the stator flange 40. The fourth spring element 22 has a first connection section 23 through which the fourth spring element 22 is coupled to a fourth intermediate ring 24, which is connected in a rotationally fixed manner to the stator flange 40, in a tensile force-transmitting manner, while a second connection section 25 of the fourth spring element 22 is connected to the second stator body 6 in a tensile force-transmitting manner. The fourth spring element 22 is again configured such that a change in the axial extent 26 of the fourth spring element 22 can be effected by a tensile force load.

[0055] The third intermediate ring 19 and the fourth intermediate ring 24 are configured such that in a first torque direction of the second stator body 6, a torque can only be transmitted from the second stator body 6 via the third intermediate ring 19 to the stator flange 40, while in a second torque direction of the second stator body 6, a torque can only be transmitted from the second stator body 6 via the fourth intermediate ring 24 to the stator flange 40.

[0056] In the embodiment shown, the Fig. 1-6, the first spring element 8, the second spring element 12, the third spring element 17 and the fourth spring element 22 are each designed as a plurality of circumferentially distributed leaf springs arranged between the corresponding intermediate rings 10, 14, 19, 24 and the rotor shaft 4.

[0057] The first spring element 8, the second spring element 12, the third spring element 17 and the fourth spring element 22 are formed essentially in the same part according to the embodiment shown.

[0058] Finally, the Fig. 2-4 also that the first intermediate ring 10 and the second intermediate ring 14 are arranged in a common radial plane 31 and the third intermediate ring 19 and the fourth intermediate ring 24 are arranged in a common radial plane 32.

[0059] Also in the Fig. 1, Fig. 5 and Fig. 6 shows that a first compensation spring element 27 applies a spring force directed axially toward the rotor 3 to the first stator body 5 and a second compensation spring element 28 applies a spring force directed axially toward the rotor 3 to the second stator body 6.

[0060] The force in the circumferential direction or the torque from the stator bodies 5,6, which is in the Fig. 3-4 is indicated by the arrows, in this design acts on the spring elements 8, 12, 17, 22, which are designed as leaf springs, each in the direction of tension. Depending on the angle of the leaf springs, these generate an additional axial force, which displaces the stator bodies 5, 6 axially towards the rotor 3. However, since the angle changes during adjustment, the resulting force also changes. For this reason, the compensation spring elements 27, 28 are designed so that the force that the leaf springs have to overcome is adapted to the change in angle. In concrete terms, this means that at the beginning of the adjustment, when the leaf springs are steep, a high differential force can be present, and at the end of the adjustment, when the leaf springs are flatter, a low differential force should be present, as can be seen in the diagrams of the Fig. 5-6 is illustrated.

[0061] In this design, the compensation force is generated by compensation spring elements 27, 28 designed as leaf springs, which are subjected to tensile stress. These compensation spring elements 27, 28, designed as leaf springs, are supported on the rotor shaft 4 by means of needle bearings (not further specified), as can be seen from the Fig. 1. However, if one wishes to utilize the frictional influence of the compensation spring elements 27, 28 designed as leaf springs, which varies greatly depending on the direction, the needle bearing can be omitted.

[0062] As can be seen from the axial force-air gap width diagrams of the Fig. As can be seen in Figures 5-6, the magnetic force varies depending on the size of the air gaps L1, L2, so the spring force must also change along the adjustment path. To keep the force acting on the air gap adjustment 7 as small as possible, the force difference between the two characteristic curves must be kept as small as possible.

[0063] However, it is important to ensure that the spring force is always greater than the magnetic force so that a preload remains on the air gap adjustment 7. The adjustment is achieved by the applied torque in the axial flux machine, which generates an additional axial force via the described leaf spring mechanism, which leads to the axial adjustment of the first stator body 5 and the second stator body 6 relative to the rotor 3.

[0064] It is also clear from the figure that the axial movement of the first stator body 5 towards the rotor 3 is limited by a mechanical stop and / or the axial movement of the second stator body 6 towards the rotor 3 is limited by a mechanical stop.

[0065] 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 axial flux machine 2 Stator 3 Rotor 4 Rotor shaft 5 Stator body 6 Stator body 7 Air gap adjustment 8 spring element 9 Connection section 10 intermediate ring 11 Extension 12 spring element 13 connecting section 14 intermediate ring 15 connecting section 16 Extension 17 Spring element 18 connecting section 19 intermediate ring 20 connection section 21 Extension 22 Spring element 23 connecting section 24 intermediate ring 25 connecting section 26 Extension 27 Compensation spring element 28 Compensation spring element 31 Level 32 levels 33 connecting section 35 rotor body 40 Stator flange

Claims

[1] Electric axial flux machine (1) comprising: a stator (2), a disk-shaped first stator body (5) and a disk-shaped second stator body (6) axially spaced from it, and a rotor (3) rotatable relative to the stator (2) with a disk-shaped rotor body (35) arranged non-rotatably on a rotor shaft (4), which is arranged axially between the first stator body (5) and the second stator body (6), wherein a mechanical air gap adjustment (7) is provided in a torque flow between the first stator body (5) and a stator flange (40) and / or between the second stator body (6) and the stator flange (40), to displace the first stator body (5) and / or the second stator body (6) in the axial direction to adjust at least one air gap (L1, L2) between one of the stator bodies (5,6) and the rotor body (35), In the torque flow between the first stator body (5) and the stator flange (40) a first spring element (8) is arranged, which has a first connection section (9) through which the first spring element (8) is coupled in a tensile force-transmitting manner to a first intermediate ring (10) which is rotationally fixed to the stator flange (40), while a second connection section (33) of the first spring element (8) is connected in a tensile force-transmitting manner to the first stator body (5), and the first spring element (8) is configured such that a change in the axial extension (11) of the first spring element (8) can be effected by a tensile force load. In the torque flow between the first stator body (5) and the stator flange (40), a second spring element (12) is arranged, which has a first connection section (13) through which the second spring element (12) is coupled in a tensile force-transmitting manner to a second intermediate ring (14) which is rotationally fixed to the stator flange (40), while a second connection section (15) of the second spring element (12) is connected in a tensile force-transmitting manner to the first stator body (5), and the second spring element (12) is configured such that a change in the axial extension (16) of the second spring element (12) can be effected by a tensile force load, and the first intermediate ring (10) and the second intermediate ring (14) are configured such that in a first torque direction of the first stator body (5) a torque can only be transmitted from the first stator body (5) via the first intermediate ring (10) to the stator flange (40), while in a second torque direction of the first stator body (5) a torque can only be transmitted from the first stator body (5) via the second intermediate ring (14) to the stator flange (40). [2] Axial flux machine (1) according to claim 1, characterized by , that a third spring element (17) is arranged in a torque flow between the second stator body (6) and the stator flange (40), which has a first connection section (18) through which the third spring element (17) is coupled to a third intermediate ring (19) which is rotationally fixed to the stator flange (40) in a tensile force transmission, while a second connection section (20) of the third spring element (17) is connected to the second stator body (6) in a tensile force transmission, and the third spring element (17) is configured such that a change in the axial extension (21) of the third spring element (17) can be effected by a tensile force load, In the torque flow between the second stator body (6) and the stator flange (40), a fourth spring element (22) is arranged, which has a first connection section (23) through which the fourth spring element (22) is coupled to a fourth intermediate ring (24) which is rotationally fixed to the stator flange (40) in a tensile force-transmitting manner, while a second connection section (25) of the fourth spring element (22) is connected to the second stator body (6) in a tensile force-transmitting manner, and the fourth spring element (22) is configured such that a change in the axial extension (26) of the fourth spring element (22) can be effected by a tensile force load, and the third intermediate ring (19) and the fourth intermediate ring (24) are configured such that in a first torque direction of the second stator body (6) a torque can only be transmitted from the second stator body (6) via the third intermediate ring (19) to the stator flange (40), while in a second torque direction of the second stator body (6) a torque can only be transmitted from the second stator body (6) via the fourth intermediate ring (24) to the stator flange (40). [3] Axial flux machine (1) according to any one of the preceding claims, characterized by , that the first spring element (8) and / or the second spring element (12) and / or the third spring element (17) and / or the fourth spring element (22) comprise at least one leaf spring. [4] Axial flux machine (1) according to any one of the preceding claims, characterized by, that the first spring element (8) and / or the second spring element (12) and / or the third spring element (17) and / or the fourth spring element (22) comprise a plurality of leaf springs arranged circumferentially distributed between the corresponding intermediate rings (10,14,19,24) and stator bodies (5,6). [5] Axial flux machine (1) according to any one of the preceding claims, characterized by , that the first spring element (8), the second spring element (12), the third spring element (17) and the fourth spring element (22) are essentially identical in design. [6] Axial flux machine (1) according to any one of the preceding claims, characterized by , that the first spring element (8) has a spring constant different from the second spring element (12) and / or the third spring element (17) has a spring constant different from the fourth spring element (22). [7] Axial flux machine (1) according to any one of the preceding claims, characterized by, that the spring constant of the first spring element (8) is essentially equal to the spring constant of the third spring element (17) and / or the spring constant of the second spring element (12) is essentially equal to the spring constant of the fourth spring element (22). [8] Axial flux machine (1) according to any one of the preceding claims, characterized by , that a first compensation spring element (27) applies a spring force to the first stator body (5) directed axially towards the rotor (3) and / or a second compensation spring element (28) applies a spring force to the second stator body (6) directed axially towards the rotor (3). [9] Axial flux machine (1) according to any one of the preceding claims, characterized by, that the axial movement of the first stator body (5) towards the rotor (3) is limited by a mechanical stop and / or the axial movement of the second stator body (6) towards the rotor (3) is limited by a mechanical stop. [10] Axial flux machine (1) according to any one of the preceding claims, characterized by , that the first intermediate ring (10) and the second intermediate ring (14) are arranged in a common radial plane (31) and / or the third intermediate ring (19) and the fourth intermediate ring (24) are arranged in a common radial plane (32).

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