Electric machine, method for producing a mechanical magnetic-field-attenuating mechanism, mechanical magnetic-field-attenuating mechanism, and kit of parts

Abstract

The invention relates to an electric machine (1), in particular for use within the powertrain of a hybrid or fully electrically driven motor vehicle, comprising a stator (2) and a rotor (4) which is separated from the stator (2) by an air gap (3), wherein the rotor (4) has at least one first rotor body (5) with a first group of permanent magnets (6) and a second rotor body (7) with a second group of permanent magnets (8). The first rotor body (5) and the second rotor body (7) can be rotated relative to each other about a common rotational axis (10) against the effect of a first rotational stiffness (9) by means of a mechanical field-attenuating mechanism (11), and at least one first spring leg (17) of the first leg spring (13) is held in a first receiving shoe (30), which is received in a first receiving pocket (31) of the first rotor body (5) and is fixed to the first rotor body (5) such that the first spring leg (17) of the first leg spring (13) is coupled to the first rotor body in a play-free manner in the axial direction as well as in the circumferential direction relative to the first rotor body (5).

Description

[0001] ELECTRICAL MACHINE, METHOD FOR MANUFACTURING A MECHANICAL MAGNETIC FIELD WEAKENING MECHANISM, MECHANICAL MAGNETIC FIELD WEAKENING MECHANISM, AND KIT OF PARTS

[0002] The present invention relates to an electric machine, in particular for use within a drive train of a hybrid- or fully electric-powered motor vehicle, comprising a stator and a rotor separated from the stator by an air gap, wherein the rotor has at least a first rotor body with a first group of permanent magnets and a second rotor body with a second group of permanent magnets, wherein the first rotor body and the second rotor body are rotatable relative to one another against the effect of a first torsional stiffness about a common axis of rotation by means of a mechanical field weakening mechanism. The invention further relates to a method for producing a mechanical field weakening mechanism, a mechanical field weakening mechanism, and a kit of parts.

[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 includes an electric motor arranged coaxially with a bevel gear differential. Such drive units are also referred to as e-axles or electrically operated drive trains. During operation, electric machines are subject to losses due to magnetization reversal, which are summarized as iron losses and reduce the machine efficiency. In mobile applications, a low efficiency of the electric machine means a reduced range of the vehicle and increased demand for battery capacity.It is therefore a constant goal, especially in mobile applications with purely electric drive, to minimize the iron losses described.

[0005] An example of such an electrical machine with iron losses, which can be used within the drivetrain of a hybrid or fully electric motor vehicle, is the so-called permanent-magnet synchronous machine. Due to its high power density compared to other machine types, it is particularly popular in the field of electromobility, where the available installation space is often a limiting factor. The machine's excitation field is usually generated by permanent magnets arranged in the machine's rotor. Slip ring contact, which is necessary in electrically excited synchronous machines to supply current to an excitation coil arranged on the rotor, can be dispensed with in the permanent-magnet synchronous machine.

[0006] A disadvantage of permanent magnet excitation, however, is that the excitation field cannot be easily modified. In principle, a synchronous machine can be operated beyond its rated speed by controlling the so-called field weakening range. In this range, the machine operates at its maximum rated power, with the torque output by the machine reducing as the speed increases. Electrically excited synchronous machines can be operated very easily in the field weakening range by reducing the excitation current. Even with permanent magnet machines, there are known ways of generating an air gap field component by applying a suitable current to the stator of the machine. This air gap field component counteracts the excitation field generated by the permanent magnets and thus weakens it.However, this type of control of the machine results in increased losses, meaning the machine can only be operated at reduced efficiency in this range. An effective method for reducing iron losses in electrical machines is the targeted weakening of the magnetic field between the stator and rotor at high-speed operating points, since losses due to high-frequency remagnetization are lower in a weaker magnetic field. In addition to electrical methods, there are also mechanical approaches for targeted field weakening.Patents US58211710, FR2831345, EP1085644, EP11867030, DE1012011708670, DE1012016103470, CN104600929, and CN 105449969 disclose a rotor of a radial flux machine divided perpendicular to the rotation axis into several rotor disks equipped with permanent magnets that can be rotated relative to one another. Depending on the relative rotation between the rotor disks, the rotor provides the full magnetic field in a position with the magnetic poles aligned in the axial direction and a weakened magnetic field in a position rotated relative to the rotor disk. Active or passive mechanisms are described that claim to be able to switch between these two positions depending on the rotor speed or torque, thus enabling more efficient operation of the electric machine across the entire motor characteristic map.

[0007] DE 10 12021 101 898 describes an arrangement in which the rotor of a radial flux machine is divided into two sub-rotors, whose individual rotor disks alternate in the axial direction. One sub-rotor is connected directly to the rotor shaft, while the other sub-rotor is connected to the rotor shaft in a torque-transmitting manner via a torsional stiffness. The torsional stiffness is selected such that at low torques, the sub-rotors are in a torsional position with a weakened magnetic field, and at high torques, the sub-rotors are in a torsional position with a full magnetic field. DE 10 12021 101 904 claims a structurally designed mechanical module that can be inserted into the interior of the permanent-magnet-equipped rotor disks, establishes the described connections between the sub-rotors and the rotor shaft, and allows an adjustment characteristic to be defined via the torsional stiffness, which is implemented using springs and roller-equipped cam gears.All of the previously mentioned passive solutions, which use a torque as a sensor variable to trigger a relative rotation between two partial rotors against a torsional stiffness, assume that the total electromagnetic torque generated by the stator current in the case of the initially field-weakened position with non-aligned magnetic poles is simply distributed between the two partial rotors, roughly according to their share of the total length and their respective phase position to the stator field, regardless of the presence of the other partial rotor. Only then could a partial torque proportional to the total torque be readily directed against a torsional stiffness between the partial rotors or one of the partial rotors and the rotor shaft, and cause the desired rotation with increasing torque into the position with full magnetic field with aligned magnetic poles.However, tests and modelling by the applicant have shown that the actual circumstances are far more complicated.

[0008] Even in the de-energized state, interactions occur between the rotor disks of the two sub-rotors in the form of magnetic repulsion moments. The position with the full magnetic field and aligned magnetic poles represents a fragile equilibrium with a vanishing repulsion moment. As rotation begins from this equilibrium position, a repulsion moment arises that increases with increasing rotation until it reaches a maximum, before then decreasing again with further rotation. The progression of the repulsion moment over the angle of rotation within an electrical period, the height of the maximum, and the angle of rotation at which it occurs depend heavily on the chosen arrangement of the permanent magnets within the rotor disks. The progression over an electrical period is fundamentally non-linear.

[0009] In the case of the desired efficient stator current supply for different speeds, these magnetic repulsion moments increase in different ways, sometimes several times over, depending on the speed. Overall, the resulting partial moments are in no way suitable for simply counteracting the torsional rigidity between the partial rotors or one of the partial rotors and the rotor shaft, causing the partial rotors to rotate into the position with full magnetic field, since they are not directed in the correct direction due to the high proportion of magnetic repulsion moments.

[0010] For reliable adjustment behavior, it is necessary, among other things, that the adjustment characteristic of the mechanical field weakening neither changes undesirably nor exhibits excessive hysteresis over the engine map. However, at the speeds of today's traction motors in the automotive sector, centrifugal forces, particularly on the existing torsional stiffnesses, which can be designed as compression springs, cause an undesirably large shift in the adjustment characteristic toward higher torques. Increasing friction on guide elements of the torsional stiffnesses can also lead to excessive hysteresis in the adjustment characteristic.

[0011] In order to provide a functional arrangement in the sense of the aforementioned passive solutions for torque-adaptive field weakening of the rotor of an electrical machine, the object of the present invention is to provide an electrical machine with improved mechanical field weakening. Furthermore, the object is to implement an optimized method for producing a field weakening mechanism and an improved mechanical field weakening mechanism. The object of the invention is also to provide a kit of parts for producing a mechanical field weakening mechanism for a rotor of an electrical machine.

[0012] This object is achieved by an electric 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 rotor has at least a first rotor body with a first group of permanent magnets and a second rotor body with a second group of permanent magnets, wherein the first rotor body and the second rotor body are rotatable relative to one another against the effect of a first torsional stiffness about a common axis of rotation by means of a mechanical field weakening mechanism, wherein the first torsional stiffness is designed as a first leg spring arrangement with a first leg spring, which is arranged coaxially to the axis of rotation and thus between the first rotor body and the second rotor body or between one of the rotor bodies and a rotor shaft,that the rotation of one of the rotor bodies which occurs during the adjustment of the field weakening mechanism causes an opening or closing actuation of the first leg spring, wherein at least one first spring leg of the first leg spring is held in a first receiving shoe, which in turn is received in a first receiving pocket of the first rotor body and is fixed to the first rotor body in such a way that the first spring leg of the first leg spring is coupled to the first rotor body in both the axial and circumferential directions without play relative to the first rotor body.

[0013] This provides the advantage of creating an electric machine with a purely mechanical field weakening device that reliably and cost-effectively adjusts the positions of permanent magnets within the rotor required for field weakening as required, depending on the operating conditions of torque and speed. The invention thus fundamentally eliminates the need for actuators that intervene externally on or in the rotor.

[0014] The formation of a torsional stiffness as a leg spring arrangement to define an adjustment characteristic to weaken the magnetic field by a relative rotation of the rotor bodies allows in particular the reduction of the centrifugal force influence on the adjustment characteristic and its hysteresis.

[0015] The play-free arrangement of a spring leg in a receiving shoe enables a very precise positioning of the spring leg in the corresponding receiving pocket, which also contributes to a play-free arrangement of the spring leg relative to the rotor body and to a corresponding tolerance compensation between the joined components.

[0016] This connection also allows the center of gravity of the torsion spring to be precisely adjusted to the rotational axis of the rotor, which is particularly important with regard to imbalance at high rotor speeds above 15,000 rpm.

[0017] A receiving shoe is preferably configured so that it can transmit both a moment and forces that may, for example, arise from the reaction forces of the leg springs.

[0018] It is further preferred that the contact points between a spring leg and a spring shoe, and possibly a wall of a receiving pocket, lie on different radii, which allows for forces to be introduced into the leg spring without transverse forces. This can, among other things, contribute to a particularly firm and secure clamping of a spring leg.

[0019] The electric machine can, in particular, be designed as a rotary machine. In the case of electric machines designed as rotary machines, a distinction is made in particular between radial flux machines and axial flux machines. A radial flux machine is characterized by the fact that the magnetic field lines in the air gap formed between the rotor and stator extend in the radial direction, whereas in the case of an axial flux machine, the magnetic field lines in the air gap formed between the rotor and stator extend in the axial direction. In the context of this invention, it is possible for the electric machine to be configured as a radial flux machine or an axial flux machine.

[0020] A rotor is the rotating part of an electrical machine. The rotor comprises, in particular, a rotor shaft and one or more rotor bodies formed from rotor cores, arranged in a rotationally fixed manner on the rotor shaft. The rotor shaft can be hollow, which not only reduces weight but also allows the supply of lubricant or coolant to the rotor body.

[0021] For the purposes of the invention, a rotor body is understood to mean the rotor without the rotor shaft. The rotor body is therefore composed, in particular, of a rotor core and the permanent magnets incorporated into the pockets of the rotor core or fixed circumferentially to the rotor core, as well as any axial cover parts for closing the pockets.

[0022] The permanent magnets can preferably be incorporated into the pockets of the rotor core. A single larger rotor magnet designed as a bar magnet or several smaller permanent magnet elements can be provided per pocket.

[0023] The rotor has a plurality of rotor bodies. Particularly preferably, the rotor bodies are formed from substantially the same parts, in particular substantially identical. It is most preferred for the rotor bodies to be formed from substantially the same parts, in particular substantially identical rotor laminations. The rotor bodies are therefore particularly preferably formed from a rotor lamination stack, which is composed of a plurality of laminated individual laminations or rotor laminations, generally made of electrical steel sheet, which are layered and stacked one on top of the other to form a stack, the so-called rotor lamination stack. The individual laminations can be held together in the rotor lamination stack by gluing, welding, or screwing. A rotor lamination stack can, in particular, also have permanent magnets introduced into the pockets of the rotor lamination stack or fixed circumferentially to the rotor lamination stack.

[0024] Mechanical field weakening mechanisms are generally known from the prior art. Particularly preferred mechanical field weakening mechanisms in connection with this invention are described in the as yet unpublished DE102022106944 and DE102022106945, as well as in the patent publications DE102021101904B3, DE102021101898A1, and DE102021101900A1, and are hereby incorporated by reference into the disclosure of this application.

[0025] According to an advantageous embodiment of the invention, the first leg spring arrangement can have a second leg spring which is arranged coaxially to the axis of rotation of the rotor and between the first rotor body and the second rotor body, or between one of the rotor bodies and the rotor shaft, such that the rotation of one of the rotor bodies that occurs when the field weakening mechanism is adjusted causes the second leg spring to open or close. The advantage of this embodiment is that a second leg spring makes the adjustment characteristic particularly easy to model and precisely adjustable. The leg springs can be designed to be essentially identical or different from one another, depending on which application-specific requirements must be implemented by the desired adjustment characteristic. The leg springs can be connected in series or in parallel.

[0026] According to a further preferred development of the invention, it can also be provided that the first leg spring has a first spring leg extending radially into the first rotor body and / or a second spring leg extending radially into the second rotor body, and / or the first leg spring has a first spring leg extending axially into the first rotor body and / or a second spring leg extending axially into the second rotor body, and / or the second leg spring has a first spring leg extending radially into the first rotor body and / or a second spring leg extending radially into the second rotor body, and / or the second leg spring has a first spring leg extending axially into the first rotor body and / or a second spring leg extending axially into the second rotor body.This makes it possible to achieve particularly compact torsional rigidities radially or axially, depending on the given installation space situation.

[0027] Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the first leg spring and the second leg spring are made essentially of the same part and are arranged rotated by approximately 180° about the axis of rotation, so that the first spring leg and the second spring leg of the first leg spring point in a common radial and / or axial direction and the first spring leg and the second spring leg of the second leg spring are oriented in an opposite radial and / or axial direction. The advantageous effect of this embodiment is that transverse forces which occur when the leg springs are actuated and a structural imbalance in the rotating rotor can be avoided or at least reduced. For example, a package of two identical opening and closing springs can then be arranged.Closing leg springs are formed by screwing the first and second leg springs together, enabled by a corresponding coil spacing, and then arranging them rotated 180° relative to each other. For this purpose, the leg springs preferably have a coil spacing that is slightly larger than the wire thickness of the leg springs in the axial direction.

[0028] In a likewise preferred embodiment of the invention, it can also be provided that at least one, preferably all, leg springs are wound from a spring wire with a substantially rectangular cross-section. This can increase the energy content of the leg springs in their installation space and facilitate the bending moment-transmitting and transverse force-free suspension of the spring ends designed as legs in recesses of discs, which form a structural unit with the partial rotors or the rotor shaft for torque transmission.

[0029] It may also be advantageous to further develop the invention in such a way that at least one, preferably all, leg springs are preloaded. The advantage of this is that a moment can be defined at which the adjustment process should begin. For this purpose, the leg springs in the arrangement can then be preloaded, for example, by a specific angle of rotation.

[0030] According to an advantageous embodiment of the invention, it can be provided that the first receiving shoe can be inserted into the first receiving pocket with some play. The advantage of this embodiment is that the position of the first spring leg of the first leg spring can be slightly changed and thus adjusted without impairing the coupling between the first spring leg and the first rotor body.

[0031] According to a further preferred development of the invention, the first receiving shoe can also have a first receiving groove in which the first spring leg of the first leg spring is arranged without play. This allows for precise adjustment of the adjustment characteristic of the leg spring arrangement. A further advantage is that it reduces friction between the components and thus increases the service life of the leg spring arrangement.

[0032] Furthermore, according to a similarly advantageous embodiment of the invention, it can be provided that the first spring leg of the first leg spring protrudes from the first receiving groove, with the portion protruding from the first receiving groove resting against a wall of the first receiving pocket. The advantageous effect of this embodiment is that it allows some of the mechanical loads during operation of the rotor to be absorbed by the corresponding rotor body.

[0033] According to another particularly preferred embodiment of the invention, the wall of the first receiving pocket may have a convex contour extending into the first receiving pocket. This allows, in particular, the effect of extensive adjustability of the positioning of the spring leg relative to the receiving pocket.

[0034] Furthermore, the invention can also be further developed in such a way that the first receiving shoe has a first opening through which a first fastening means passes, by means of which the first receiving shoe is fixed to the first rotor body. The advantage of this embodiment is that it can provide a particularly assembly-friendly adjustability of the freedom of play between the receiving shoe and the receiving pocket. In a likewise preferred embodiment of the invention, it can also be provided that the first leg spring arrangement has a second leg spring, which is arranged coaxially to the axis of rotation of the rotor and between the first rotor body and the second rotor body or between one of the rotor bodies and the rotor shaft, such that the rotation of one of the rotor bodies that occurs during the adjustment of the field weakening mechanism,causes an opening or closing actuation of the second leg spring, and the first leg spring and the second leg spring are designed essentially in the same part and are arranged rotated by approximately 180° about the axis of rotation, so that the first spring leg and a second spring leg of the first leg spring point in a common radial and / or axial direction and a first spring leg and a second spring leg of the second leg spring are oriented in an opposite radial and / or axial direction.

[0035] It may also be advantageous to further develop the invention in such a way that the second spring leg of the first leg spring is held in a second receiving shoe, which in turn is received in a second receiving pocket of the second rotor body and fixed to the first rotor body in such a way that the second spring leg of the first leg spring is coupled to the second rotor body in both the axial and circumferential directions without play, and / or the first spring leg of the second leg spring is held in a third receiving shoe, which in turn is received in a third receiving pocket of the first rotor body and fixed to the first rotor body in such a way that the first spring leg of the second leg spring is coupled to the first rotor body in both the axial and circumferential directions without play, and / or the second spring leg of the second leg spring is held in a fourth receiving shoe,which, in turn, is received in a fourth receiving pocket of the second rotor body and fixed to the second rotor body in such a way that the second spring leg of the second leg spring is coupled to the second rotor body without play in both the axial and circumferential directions. The advantage that can be realized in this way is that the adjustability of the adjustment characteristic can be improved accordingly. According to a further preferred embodiment of the subject matter of the invention, it can be provided that the first receiving shoe, the second receiving shoe, the third receiving shoe, and the fourth receiving shoe are formed from the same parts. This can achieve a reduction in the manufacturing costs for the receiving shoes due to the increased degree of uniformity.

[0036] The object of the invention can also be achieved by a method for producing a mechanical field weakening mechanism, comprising the following steps:

[0037] • Providing a first rotor body with a first receiving pocket and a second rotor body,

[0038] • Providing a first torsional stiffness, which is designed as a first leg spring arrangement with a first leg spring, which has a first spring leg and a second spring leg,

[0039] • Provision of a first receiving shoe,

[0040] • Play-free fixing of the first receiving shoe to the first spring leg,

[0041] • Playful insertion of the first receiving shoe into the first receiving pocket and

[0042] • Fixing the receiving shoe to the first rotor body so that the first spring leg of the first leg spring is coupled to the first rotor body without play in the axial and circumferential directions, • Coupling the second spring leg to the second rotor body or a rotor shaft,

[0043] • so that the first rotor body and the second rotor body are rotatable relative to one another about a common axis of rotation against the effect of the first torsional rigidity, so that when the field weakening mechanism is adjusted, rotation of one of the rotor bodies can cause an opening or closing actuation of the first leg spring.

[0044] The object of the invention can also be achieved by a mechanical field weakening mechanism for a rotor of an electrical machine, in particular for use within a drive train of a hybrid or fully electric motor vehicle, wherein the rotor has at least a first rotor body and a second rotor body, wherein the first rotor body and the second rotor body are rotatable relative to one another against the effect of a first torsional stiffness about a common axis of rotation, wherein the first torsional stiffness is designed as a first leg spring arrangement with a first leg spring, which is coaxial to the axis of rotation and arranged between the first rotor body and the second rotor body or between one of the rotor bodies and a rotor shaft, that the rotation of one of the rotor bodies which begins during the adjustment of the field weakening mechanism,causes an opening or closing actuation of the first leg spring, wherein at least one first spring leg of the first leg spring is held in a first receiving shoe, which in turn is received in a first receiving pocket of the first rotor body and fixed to the first rotor body in such a way that the first spring leg of the first leg spring is coupled to the first rotor body in both the axial and circumferential directions without play relative to the first rotor body.

[0045] Furthermore, the object of the invention can also be achieved by a kit of parts for producing a mechanical field weakening mechanism for a rotor of an electric machine, in particular for use within a drive train of a hybrid or fully electric motor vehicle, comprising

[0046] • a first rotor body with a first receiving pocket and a second rotor body, wherein the first rotor body and the second rotor body are rotatable relative to each other about a common axis of rotation against the effect of a first torsional stiffness,

[0047] • a first torsional stiffness, which is designed as a first leg spring arrangement with a first leg spring, which is coaxial to the axis of rotation and can be positioned between the first rotor body and the second rotor body or between one of the rotor bodies and a rotor shaft, such that the rotation of one of the rotor bodies which begins when the field weakening mechanism is adjusted, an opening or closing actuation of the first leg spring can be effected, and the first leg spring has at least one first spring leg,

[0048] • a first receiving shoe in which the first spring leg can be positioned and the receiving shoe can in turn be received in the first receiving pocket of the first rotor body and can be fixed to the first rotor body in such a way that the first spring leg of the first leg spring can be coupled to the first rotor body in the axial and circumferential directions without play relative to the first rotor body.

[0049] One advantage of the kit of parts is that it provides a simple and flexible solution for the manufacture and assembly of a mechanical

[0050] Field weakening mechanism. The use of preconfigured and pre-assembled parts makes installation and maintenance easier and faster. The kit of parts is also more flexible and adaptable for different applications and vehicle types. It can also reduce costs by simplifying the supply chain and reducing inventory levels. The kit of parts can, for example, be a single packaging unit. Furthermore, it is possible to design the kit of parts as a collection of separate storage containers for storing the individual components or the respective component groups of the kit of parts.

[0051] The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

[0052] It shows:

[0053] Figure 1 shows an electrical machine in a cross-sectional view,

[0054] Figure 2 is a schematic block diagram of a rotor with a mechanical field weakening mechanism,

[0055] Figure 3 shows a first embodiment of a leg spring arrangement with two rotor bodies in a perspective exploded view,

[0056] Figure 4 shows a first embodiment of a leg spring arrangement with two rotor bodies in an assembled state in a perspective view,

[0057] Figure 5 shows a rotor body with a first embodiment of a leg spring arrangement fixed to it in a perspective view,

[0058] Figure 6 shows a rotor body with a first embodiment of a leg spring arrangement fixed to it in a cross-sectional view,

[0059] Figure 7 shows a rotor body with a first embodiment of a leg spring arrangement fixed to it in a detailed enlarged section,

[0060] Figure 8 shows a rotor body with a first embodiment of a leg spring arrangement fixed to it in an axial sectional view, Figure 9 shows a first embodiment of a leg spring arrangement in a perspective view,

[0061] Figure 10 shows three embodiments of a receiving shoe for a spring leg, each in a perspective view,

[0062] Figure 11 shows a fourth embodiment of a receiving shoe with a leg spring arrangement in a perspective view,

[0063] Figure 12 shows a rotor body with a leg spring arrangement fixed to it in a perspective view,

[0064] Figure 13 shows a rotor body with a further embodiment of a leg spring arrangement fixed to it in a perspective view,

[0065] Figure 14 shows a kit of parts for producing a mechanical field weakening mechanism for a rotor of an electrical machine,

[0066] Figure 15 shows a rotor in a cross-sectional view,

[0067] Figure 16 shows a detailed view of the rotor in a cross-sectional view.

[0068] Figure 1 shows an electric machine 1, in particular for use within a drive train of a hybrid or fully electric motor vehicle. The electric machine 1, configured as a radial flux machine, comprises a stator 2 and a rotor 4 separated from the stator 2 by an air gap 3, wherein the rotor 4 has at least a first rotor body 5 with a first group of permanent magnets 6 and a second rotor body 7 with a second group of permanent magnets 8, which can be clearly seen from the combination of Figure 1 and Figure 2. The first rotor body 5 and the second rotor body 7 can be rotated relative to one another about a common axis of rotation 10 by means of a mechanical field weakening mechanism 11, counter to the effect of a first torsional stiffness 9.The two rotor bodies 5,7 are essentially formed from identical rotor laminations, wherein the position and number of the permanent magnets 6 of the first group and the number of permanent magnets 8 of the second group in the rotor bodies 5,7 are identical.

[0069] The field weakening mechanism 11 shown as an example in Figure 2 comprises a lever element (not further identified) that can be pivoted about a pivot point, wherein the first rotor body 5 can be coupled to a first lever section and the second rotor body 7 can be coupled to a second lever section of the lever element. The first lever section and the second lever section are arranged on opposite sides of the lever, so that the first rotor body 5 and the second rotor body 7 can be rotated relative to one another by tilting the lever element for a desired adjustment of the mechanical field weakening mechanism 11. This field weakening mechanism 11 is described in detail in DE102022106944 and DE102022106945, so that reference is made here to these documents to avoid repetition.

[0070] As can be seen from Figure 3, the first torsional stiffness 9 is designed as a first leg spring arrangement 12 with a first leg spring 13, which is arranged coaxially to the axis of rotation 10 and between the first rotor body 5 and the second rotor body 7 in such a way that the rotation of one of the rotor bodies 5, 7 that occurs during the adjustment of the field weakening mechanism 11 causes an opening or closing actuation of the first leg spring 13. Even if it is not shown in the figures, it is nevertheless possible for the first leg spring 13 to be arranged between one of the rotor bodies 5, 7 and the rotor shaft 16 in a torque-transmitting manner.

[0071] The first leg spring arrangement 12 has a second leg spring 14 which is arranged coaxially to the axis of rotation 10 of the rotor 4 and between the first rotor body 5 and the second rotor body 7 in such a way that the rotation of one of the rotor bodies 5, 7 which occurs during the adjustment of the field weakening mechanism 11 causes an opening or closing actuation of the second leg spring 14. As shown in Figure 3, the first leg spring 13 and the second leg spring 14 are designed essentially in the same part and are arranged rotated by approximately 180° about the axis of rotation 10 relative to one another, so that the first spring leg 17 and the second spring leg 18 of the first leg spring 13 point radially outwards offset by 90° in the circumferential direction and the first spring leg 19 and the second spring leg 20 of the second leg spring 14 are also oriented radially outwards offset by 90° in the circumferential direction.

[0072] Here, the first leg spring 13 has a first spring leg 17 extending radially into the first rotor body 5 and a second spring leg 18 extending radially into the second rotor body 7. Analogously, the second leg spring 14 also has a first spring leg 19 extending radially into the first rotor body 5 and a second spring leg 20 extending radially into the second rotor body 7.

[0073] The first spring leg 17 of the first leg spring 13 is held in a first receiving shoe 30, which in turn is received in a first receiving pocket 31 of the first rotor body 5 and fixed to the first rotor body 5 such that the first spring leg 17 of the first leg spring 13 is coupled to the first rotor body 5 without play in both the axial and circumferential directions. The first receiving shoe 30 can be inserted into the first receiving pocket 31 with some play, which can also be clearly seen in Figure 7, where the gap between the receiving shoe 41 and the receiving pocket 42 is clearly visible.

[0074] Figure 3 further shows that the first receiving shoe 30 has a first receiving groove 32, in which the first spring leg 17 of the first leg spring 13 is arranged without play, for example by a press fit. Figure 10 shows various embodiments of these receiving grooves 32. The first spring leg 17 of the first leg spring 13 protrudes from the first receiving groove 32, with the section 33 protruding from the first receiving groove 32 resting against a wall 34 of the first receiving pocket 31. In this way, part of the shoe load can be absorbed by the rotor body 5. The wall 34 of the first receiving pocket 31 has a convex contour protruding into the first receiving pocket 31, which can also be clearly seen from the detailed illustration in Figure ?. This can ensure, for example, that the position of the spring leg 17 can also be adjusted in the direction of rotation.

[0075] Figure 3 further shows that the first receiving shoe 30 has a first opening 35 through which a first fastening means 36 passes, by means of which the first receiving shoe 30 is fixed to the first rotor body 5.

[0076] Figure 3 also shows that the second spring leg 18 of the first leg spring 13 is held in a second receiving shoe 37, which in turn is received in a second receiving pocket 38 of the second rotor body 7 and is fixed to the first rotor body 7 in such a way that the second spring leg 18 of the first leg spring 13 is coupled to the second rotor body 7 without play in the axial and circumferential directions.

[0077] The first spring leg 19 of the second leg spring 14 is also held in an analogous manner in a third receiving shoe 39, which in turn is received in a third receiving pocket 40 of the first rotor body 5 and is fixed to the first rotor body 5 in such a way that the first spring leg 19 of the second leg spring 14 is coupled to the first rotor body 5 without play in the axial and circumferential directions.

[0078] Finally, the second spring leg 20 of the second leg spring 14 is also held in a fourth receiving shoe 41, which in turn is received in a fourth receiving pocket 42 of the second rotor body 7 and is fixed to the second rotor body 7 in such a way that the second spring leg 20 of the second leg spring 14 is coupled to the second rotor body 7 without play in the axial and circumferential directions.

[0079] It is also clear from Figure 3 that the first receiving shoe 30, the second receiving shoe 37, the third receiving shoe 39 and the fourth receiving shoe 41 are of identical design.

[0080] By means of the receiving shoes 30, 37, 39, 41, elements whose position can be adjusted and fixed within a receiving pocket 31, 38, 40, 42 are arranged between the spring legs 17, 18, 19, 20 and the rotor bodies 5. The receiving shoes 30, 37, 39, 41 are pressed onto the spring legs 17, 18, 19, 20, for example, by means of a corresponding oversize, so that they are fixed to one another without play. The spring legs 17, 18, 19, 20 with the pre-assembled receiving shoes 30, 37, 39, 41 can be positioned in the rotor bodies 5, 7 using an assembly tool (not shown). Since a gap is formed between the receiving pockets 31, 38, 42 and the receiving shoes 30, 37, 39, 41, and the receiving shoes 30, 37, 39, 41 therefore engage in the receiving pockets 31, 38, 42 with some play, the location or position of the receiving shoes 30, 37, 39, 41 in the receiving pockets 31, 38, 42 is adjustable.The receiving shoes 30, 37, 39, 41, positioned in the receiving pockets 31, 38, 42, can then be secured by the fastening means 36. These are shown as screws in the figures. However, they can also be designed as rivets, or the fastening means 36 can be a soldered or welded joint.

[0081] Figure 4 shows the arrangement known from Figure 3 in an assembled state. To manufacture or assemble the mechanical field weakening mechanism 11, the procedure can be as follows, for example. First, a first rotor body 5 with a first receiving pocket 31 and a second rotor body 7 are provided, as well as a first torsional stiffness 9, which is designed as a first leg spring arrangement 12 with a first leg spring 13, which has a first spring leg 17 and a second spring leg 18. Furthermore, a first receiving shoe 30 is also provided. The first receiving shoe 30 is then fixed to the first spring leg 17 without play, for example by a press fit. This is followed by an insertion of the first receiving shoe 30, with the first spring leg 17 fixed therein, into the first receiving pocket 31 with some play.In this assembly position, the receiving shoe 30 is then fixed to the first rotor body 5, so that the first spring leg 17 of the first leg spring 13 is coupled to the first rotor body 5 without play in both the axial and circumferential directions. To complete the first torsional stiffness 9, the second spring leg 18 is then coupled to the second rotor body 7 or a rotor shaft 16.

[0082] As a result, the first rotor body 5 and the second rotor body 7 can then be rotated relative to one another about a common axis of rotation 10 against the effect of the first torsional stiffness 9, so that when the field weakening mechanism 11 is adjusted, the rotation of one of the rotor bodies 5, 7 can cause an opening or closing actuation of the first leg spring 13.

[0083] Figures 5-8 show the leg spring arrangement 12 in a partially assembled state on the first rotor body 5 in different views.

[0084] Figure 9 shows the leg spring assembly 12 in a cut-out, perspective view. It can be clearly seen, among other things, that the leg springs 13, 14 are formed from a spring wire with a substantially rectangular cross-section, with the short edges of the leg springs 13, 14, which have a rectangular cross-section, extending in the axial direction, while the long sides are oriented in the circumferential direction.

[0085] Figure 3 shows three different embodiments of a receiving shoe 30. In the upper variant, designated with a, the receiving groove 32 is open radially inwards and in the circumferential direction, but closed in the radial direction outwards, so that a spring leg 17 received in the receiving groove 32 can also be arranged in the receiving groove 32 without play in the radial direction outwards. In principle, it would also be conceivable to design the receiving groove 32 in a channel-like manner, so that a spring leg 17 can be inserted into the receiving groove 32 from the radial inside to the outside and fixed there without play. This variant is shown in figure b of figure 10. Furthermore, the receiving groove 32 can also be open in a radial, circumferential and axial direction, as can be seen in figure c of figure 10.

[0086] Figure 11 shows a further embodiment of a receiving shoe 30 which is shaped like a ring segment and has an opening 35 at each of its circumferential ends for receiving a fastening means 36.

[0087] Figure 12 shows a further embodiment of a leg spring arrangement 12 in which the spring leg 20 is axially prestressed by a spring element 44.

[0088] Figures 15 and 16 show an embodiment in which the inner annular disc 28 and the outer annular disc 29 are positively connected to one another in a torque-transmitting manner. For this purpose, the inner annular disc 28 has an external toothing 51 on its outer circumferential surface 50, which engages with a corresponding internal toothing 52 on an inner circumferential surface 53 of the outer annular disc 29. In this exemplary embodiment, the external toothing 51 and the internal toothing 52 are designed as plug-in toothing. To facilitate the joining of this plug-in toothing, the external toothing 51 and / or the internal toothing 52 can have a chamfer.

[0089] From the detailed illustration in Figure 16, it can be seen that the teeth 54 of the external toothing 51 each have a first undercut 55. The teeth 56 of the internal toothing 52 also have a second undercut 57, wherein the first undercut 55 and the second undercut 57 are designed such that a force can be transmitted in the radial direction between the meshing internal toothing 52 and external toothing 51. To achieve this, the teeth 54 of the external toothing 51 and the teeth 56 of the internal toothing 52 have a dovetail shape in cross-section. The two annular disks 28, 29 only touch on the oblique flanks of the dovetail-shaped teeth 54, 56. The high accuracy of the tooth shape for a positive connection is therefore limited to the oblique flanks. In addition, larger radii can be used in the tooth base of the ring disks 28,29.This reduces local stresses and enables faster, more cost-effective production of the gears 51, 52, e.g., by selecting a milling cutter with a larger diameter. The undercut 55, 57 is thus created by the inclined lateral flanks of the teeth 54, 56. With this shape, the openings of the tooth gaps in the annular discs 28, 29 are wider, which enables simpler and more cost-effective production of the gears, e.g., by broaching, shaping, or milling.

[0090] The external toothing 51 further comprises, between each two circumferentially adjacent teeth 54, a groove 58 having a groove base 59 into which a tooth 56 of the internal toothing 52 engages with a tooth tip 60, wherein the tooth tip 60 has a clearance relative to the groove base 59, which can be clearly seen from the gap shown in Figure 4. With this design, an overlap can be deliberately provided in the tooth flanks of the meshing teeth 54, 56, which, during assembly, leads to an inward preload of the inner annular disc 28 with the outer annular disc 29 and thus further reduces the stresses in the annular discs 28, 29 under rotational speed.

[0091] The permanent magnets 6, 8 are arranged in pairs in a V-shape in cross-section distributed over the circumference of an outer annular disk 29, wherein the free legs 61 of the V-shaped arrangement extend radially inward, and the V-shaped arrangement has a radially extending mirror axis 62 which runs coaxially to a radially extending mirror axis 63 of a tooth 54, 56 of the internal toothing 52 or external toothing 51. At the same time, between two circumferentially adjacent V-shaped arrangements, a radially extending mirror axis 64 is defined, which runs coaxially to a radially extending mirror axis 65 of a tooth 56 of the internal toothing 52 or external toothing 51. In this context, it can also be clearly seen from Figure 4 that the meshing teeth 54, 56, through which the mirror axes 62, 63 run, are wider in the circumferential direction than the circumferentially adjacent teeth 54, 56.The same applies to the meshing teeth 54,56 through which the mirror axes 64,65 pass.

[0092] Figure 14 shows a kit of parts 43 for producing a mechanical field weakening mechanism 11 for a rotor 4 of an electric machine 1, in particular for use within a drive train of a hybrid or fully electric motor vehicle, comprising

[0093] • a first rotor body 5 with a first receiving pocket 31 and a second rotor body 7, wherein the first rotor body 5 and the second rotor body 7 are rotatable relative to each other against the effect of a first torsional stiffness 9 about a common axis of rotation 10,

[0094] • a first torsional stiffness 9, which is designed as a first leg spring arrangement 12 with a first leg spring 13, which is coaxial to the axis of rotation 10 and can be positioned between the first rotor body 5 and the second rotor body 7 or between one of the rotor bodies 5, 7 and a rotor shaft 16, such that the rotation of one of the rotor bodies 5, 7 that occurs during the adjustment of the field weakening mechanism 11 can cause an opening or closing actuation of the first leg spring 13, and the first leg spring 13 has at least one first spring leg 17,

[0095] • a first receiving shoe 30 in which the first spring leg 17 can be positioned and the receiving shoe 30 can in turn be received in the first receiving pocket 31 of the first rotor body 5 and can be fixed to the first rotor body 5 in such a way that the first spring leg 17 of the first leg spring 13 can be coupled to the first rotor body 5 without play in the axial and circumferential directions.

[0096] As shown, the kit of parts 43 can provide a receiving shoe 30, 37, 39, 41 for all spring legs 17, 18, 19, 20 of the leg spring arrangement 12, wherein these receiving shoes 30, 37, 39, 41 are essentially identical. The invention is not limited to the embodiments illustrated in the figures. The above description is therefore not to be regarded as limiting, but rather as explanatory. The following patent claims are to be understood in such a way that a named feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. If the patent claims and the above description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a priority.

[0097] List of reference symbols

[0098] 1 electric machine

[0099] 2 Stator

[0100] 3 Air gap

[0101] 4 Rotor

[0102] 5 rotor bodies

[0103] 6 permanent magnets

[0104] 7 Rotor body

[0105] 8 permanent magnets

[0106] 9 Torsional rigidity

[0107] 10 axis of rotation

[0108] 11 Field weakening mechanism

[0109] 12 Leg spring arrangement

[0110] 13 torsion spring

[0111] 14 torsion spring

[0112] 16 Rotor shaft

[0113] 17 spring legs

[0114] 18 spring legs

[0115] 19 spring legs

[0116] 20 spring legs

[0117] 28 Ring disc

[0118] 29 Ring disc

[0119] 30 Mounting shoe

[0120] 31 Recording pocket

[0121] 32 mounting groove

[0122] Section 33

[0123] 34 wall

[0124] 35 Opening

[0125] 36 fasteners

[0126] 37 Mounting shoe

[0127] 38 Recording pocket 39 Recording shoe

[0128] 40 Recording pocket

[0129] 41 Mounting shoe

[0130] 42 Recording pocket

[0131] 43 kit of parts

[0132] 44 spring element

[0133] 50 lateral surface

[0134] 51 external gearing

[0135] 52 internal gearing

[0136] 53 lateral surface

[0137] 54 teeth

[0138] 55 undercut

[0139] 56 teeth

[0140] 57 undercut

[0141] 58 grooves

[0142] 59 groove base

[0143] 60 tooth head

[0144] 61 legs

[0145] 62 Mirror axis

[0146] 63 Mirror axis

[0147] 64 Mirror axis

[0148] 65 Mirror axis

Claims

Claims 1. An electric machine (1), in particular 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), wherein the rotor (4) has at least a first rotor body (5) with a first group of permanent magnets (6) and a second rotor body (7) with a second group of permanent magnets (8), wherein the first rotor body (5) and the second rotor body (7) are rotatable relative to one another against the effect of a first torsional stiffness (9) about a common axis of rotation (10) by means of a mechanical field weakening mechanism (11), characterized in that the first torsional stiffness (9) is designed as a first leg spring arrangement (12) with a first leg spring (13) which is coaxial with the axis of rotation (10) and is arranged between the first rotor body (5) and the second rotor body (7) or between one of the rotor bodies (5, 7) and a rotor shaft (16) in such a way that the field weakening mechanism (11) incipient rotation of one of the rotor bodies (5, 7) causes an opening or closing actuation of the first leg spring (13), wherein at least one first spring leg (17) of the first leg spring (13) is held in a first receiving shoe (30), which in turn is received in a first receiving pocket (31) of the first rotor body (5) and is fixed to the first rotor body (5) in such a way that the first spring leg (17) of the first leg spring (13) is coupled to the first rotor body (5) in an axial and circumferential direction without play relative to the latter.

2. Electrical machine (1) according to claim 1, characterized in that the first receiving shoe (30) can be inserted into the first receiving pocket (31) with some play.

3. Electrical machine (1) according to claim 1 or 2, characterized in that the first receiving shoe (30) has a first receiving groove (32) in which the first spring leg (17) of the first leg spring (13) is arranged without play.

4. Electrical machine (1) according to claim 3, characterized in that the first spring leg (17) of the first leg spring (13) protrudes from the first receiving groove (32), wherein the section (33) protruding from the first receiving groove (32) bears against a wall (34) of the first receiving pocket (31).

5. Electrical machine (1) according to claim 4, characterized in that the wall (34) of the first receiving pocket (31) has a convex contour projecting into the first receiving pocket (31).

6. Electrical machine (1) according to one of the preceding claims, characterized in that the first receiving shoe (30) has a first opening (35) through which a first fastening means (36) passes, by means of which the first receiving shoe (30) is fixed to the first rotor body (5).

7. Electrical machine (1) according to one of the preceding claims, characterized in that the first leg spring arrangement (12) has a second leg spring (14) which is arranged coaxially to the axis of rotation (10) of the rotor (4) and between the first rotor body (5) and the second rotor body (7) or between one of the rotor bodies (5, 7) and the rotor shaft (16) in such a way that the rotation of one of the rotor bodies (5, 7) which begins during the adjustment of the field weakening mechanism (11) causes an opening or closing actuation of the second leg spring (14), and the first The leg spring (13) and the second leg spring (14) are designed to be essentially identical and are arranged rotated relative to one another about the axis of rotation (10), so that the first spring leg (17) and a second spring leg (18) of the first leg spring (13) point in a common radial and / or axial direction and a first spring leg (19) and a second spring leg (20) of the second leg spring (14) are oriented in a radial and / or axial direction opposite thereto.

8. Electrical machine (1) according to claim 7, characterized in that the second spring leg (18) of the first leg spring (13) is held in a second receiving shoe (37), which in turn is received in a second receiving pocket (38) of the second rotor body (7) and fixed to the first rotor body (7) in such a way that the second spring leg (18) of the first leg spring (13) is coupled to the second rotor body (7) in an axial and circumferential direction without play and / or the first spring leg (19) of the second leg spring (14) is held in a third receiving shoe (39), which in turn is received in a third receiving pocket (40) of the first rotor body (5) and fixed to the first rotor body (5) in such a way that the first spring leg (19) of the second leg spring (14) is coupled to the second rotor body (7) in an axial,is coupled to the first rotor body (5) without play in the circumferential direction and / or the second spring leg (20) of the second leg spring (14) is held in a fourth receiving shoe (41), which in turn is received in a fourth receiving pocket (42) of the second rotor body (7) and fixed to the second rotor body (7) in such a way that the second spring leg (20) of the second leg spring (14) is coupled to the second rotor body (7) without play in the axial and circumferential directions.

9. Electrical machine (1) according to claim 8, characterized in that the first receiving shoe (30), the second receiving shoe (37), the third receiving shoe (39) and the fourth receiving shoe (41) are of identical design.

10. A method for producing a mechanical field weakening mechanism (11), comprising the following steps: • Providing a first rotor body (5) with a first receiving pocket (31) and a second rotor body (7), • Providing a first torsional stiffness (9) which is designed as a first leg spring arrangement (12) with a first leg spring (13) which has a first spring leg (17) and a second spring leg (18), • Provision of a first receiving shoe (30), • Play-free fixing of the first receiving shoe (30) to the first spring leg (17), • Inserting the first receiving shoe (30) into the first receiving pocket (31) with some play and • Fixing the receiving shoe (30) to the first rotor body (5) so that the first spring leg (17) of the first leg spring (13) is coupled to the first rotor body (5) without play in the axial and circumferential directions, • Coupling the second spring leg (18) to the second rotor body (7) or a rotor shaft (16), • so that the first rotor body (5) and the second rotor body (7) are rotatable relative to each other about a common axis of rotation (10) against the effect of the first torsional stiffness (9), so that at a Adjustment of the field weakening mechanism (11 ) Rotation of one of the rotor bodies (5,7) can cause an opening or closing actuation of the first leg spring (13).

11. Mechanical field weakening mechanism (11) for a rotor (4) of an electrical machine (1), in particular for use within a drive train of a hybrid or fully electric motor vehicle, wherein the rotor (4) has at least a first rotor body (5) and a second rotor body (7), wherein the first rotor body (5) and the second rotor body (7) are rotatable relative to one another about a common axis of rotation (10) against the effect of a first torsional stiffness (9), characterized in that the first torsional stiffness (9) is designed as a first leg spring arrangement (12) with a first leg spring (13) which is coaxial with the axis of rotation (10) and is arranged between the first rotor body (5) and the second rotor body (7) or between one of the rotor bodies (5, 7) and a rotor shaft (16) in such a way that the field weakening mechanism (11) incipient rotation of one of the rotor bodies (5, 7) causes an opening or closing actuation of the first leg spring (13), wherein at least one first spring leg (17) of the first leg spring (13) is held in a first receiving shoe (30), which in turn is received in a first receiving pocket (31) of the first rotor body (5) and is fixed to the first rotor body (5) in such a way that the first spring leg (17) of the first leg spring (13) is coupled to the first rotor body (5) in an axial and circumferential direction without play relative to the latter.

12. Kit-of-parts (43) for producing a mechanical field weakening mechanism (11) for a rotor (4) of an electric machine (1), in particular for use within a drive train of a hybrid or fully electric motor vehicle, comprising • a first rotor body (5) with a first receiving pocket (31) and a second rotor body (7), wherein the first rotor body (5) and the second rotor body (7) are rotatable relative to one another about a common axis of rotation (10) against the effect of a first torsional stiffness (9), • a first torsional stiffness (9), which is designed as a first leg spring arrangement (12) with a first leg spring (13) which is coaxial with the axis of rotation (10) and can be positioned between the first rotor body (5) and the second rotor body (7) or between one of the rotor bodies (5, 7) and a rotor shaft (16) such that the rotation of one of the rotor bodies (5, 7) which begins when the field weakening mechanism (11) is adjusted can cause an opening or closing actuation of the first leg spring (13), and the first leg spring (13) has at least one first spring leg (17), • a first receiving shoe (30) in which the first spring leg (17) can be positioned and the receiving shoe (30) can in turn be received in the first receiving pocket (31) of the first rotor body (5) and can be fixed to the first rotor body (5) in such a way that the first spring leg (17) of the first leg spring (13) can be coupled to the first rotor body (5) in an axial and circumferential direction without play.

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