Power transmission assembly for transmitting power to a rotor assembly of an externally excited electric machine, method for installing a power transmission assembly, rotor assembly comprising the power transmission assembly, and externally excited electric machine having the rotor assembly

Abstract

The invention relates to a power transmission assembly (10), in particular an inductive power transmission assembly (10), and to a rotary transformer for transmitting power to a rotor assembly of an externally excited electric machine (100), comprising a hollow rotor shaft (7), a primary assembly (1), a secondary assembly (2), and a securing element (4) which fixes the secondary assembly (2) in a cylindrical part (7a) of the hollow rotor shaft (7).

Description

[0001] Power transmission arrangement for power transmission to a rotor arrangement of an externally excited electrical machine, method for assembling a power transmission arrangement, rotor arrangement with the power transmission arrangement and externally excited electrical machine with the rotor arrangement

[0002] In the field of separately excited electric motors, power transmission arrangements are playing an increasingly important role as exciters, as they make permanent magnets or rare earths unnecessary.

[0003] In separately excited electric motors, the magnetic rotor field is generated by a current flowing through coils in the moving rotor. In commonly used drives, the electrical energy is transferred from the stationary to the rotating system using conductive slip rings.

[0004] An alternative to conductive energy transfer is offered by separately excited electric motors, where energy transfer occurs inductively. This eliminates the need for both permanent magnets and sliding contacts.

[0005] The current is transferred to the rotor via an inductive transformer. The transformer is powered by an alternating voltage from the stator. The alternating voltage is converted to direct voltage on the rotor side via a rectifier for the rotor's magnetic coils. The magnetic coils then induce a rotor magnetic field, which interacts with the stator magnetic field. This allows the motor to generate torque. The magnetic coils replace the permanent magnets. The system consisting of the inductive transformer and rectifier can also be referred to as an inductive exciter.

[0006] Electric motors are often subject to strict space constraints. However, the design of inductive exciters is limited because all moving components in the exciter must have very high speed stability. The speeds in the exciter can range from 18,000 to 24,000 revolutions per minute. Ferrite, a brittle material, is often used in exciters for the cores of the magnetic coils. This, in particular, results in significant limitations in design freedom with regard to speed stability.

[0007] When using primary and secondary ferrites for inductive excitation of a synchronous motor, a defined air gap often has to be set on the electric motor. This ensures that the ferrites do not touch each other, as this could cause damage. On the other hand, for high-power electric motors, it may be necessary to ensure a defined distance between the primary and secondary arrangements in order to transfer the desired currents to the rotor.

[0008] Furthermore, for the space-neutral integration of an inductively excited SESM rotor, for example, into the system installation space of a permanent-magnet machine, the transformer, i.e., the inductive exciter, must be arranged within the hollow rotor shaft, which can be composed of several parts. The rotor shaft consists of a central part and a side part, which contains the bearing seat for the rotor shaft. It may be desirable to retain the rotor bearing in terms of bearing type, bearing size, and bearing spacing, for example, to maintain modular compatibility with permanent-magnet rotors.

[0009] To ensure the required transmission of inductive currents, a certain minimum diameter of the transformer may be necessary. This diameter then determines the inner diameter of the central part of the rotor hollow shaft in the axial area below the stator's laminated core.

[0010] However, the inner diameters of the specified rotor bearings may be smaller than the inner diameter of the hollow shaft in the central area, which is why the transformer or the secondary side must be mounted into the rotor shaft before a multi-part rotor shaft can be assembled or the side part of the hollow rotor shaft can be mounted. This also applies to the primary side of the inductive rotary transformer if it has a larger diameter in the area below the rotor bearing on the side where the transformer is located than a possible inner diameter of the rotor shaft or a side part of the rotor shaft, which could be a bearing end and tapers accordingly.

[0011] Accordingly, the stator-fixed, non-rotating primary side of the transformer must be inserted into the rotor before joining, finishing and completing it, since it will no longer fit through the lateral opening of the hollow shaft later.

[0012] Furthermore, it must be ensured that the primary side of the inductive transformer is held securely enough to prevent it from being damaged during motor manufacturing, for example, when inserted into the hollow rotor shaft, or damaging another part. Furthermore, it must be ensured that the primary side of the transformer is positioned sufficiently precisely relative to the secondary side during operation to maintain the previously defined air gap and prevent contact between the primary and secondary ferrites, as this could cause damage to the primary and secondary ferrites, or even damage the rotor bearing.

[0013] Previous arrangements and assembly methods are unable to secure the primary side to the stator before joining a bearing end or side part of a rotor shaft, or to position and secure the primary side relative to the rotor-side components, such as the secondary side, which is non-rotatably connected to the rotor. As a result, the primary side sits loosely in the hollow shaft and can thus be damaged. "Stator-secure" here means, for example, that the primary side of the transformer does not rotate with it.

[0014] The object of the present invention is therefore to provide a power transmission arrangement, a rotor arrangement, and a separately excited electrical machine in which the above-mentioned disadvantages are at least partially reduced. This object is achieved by a power transmission arrangement according to claim 1, a method for mounting a power transmission arrangement in a hollow rotor shaft according to claim 10, a rotor arrangement according to claim 11, a separately excited electrical machine according to claim 12, and a motor vehicle according to claim 13.

[0015] Further aspects and features of the present invention emerge from the dependent claims, the accompanying drawings and the following description of embodiments.

[0016] According to a first aspect, the present invention provides a power transmission arrangement, in particular an inductive power transmission arrangement, for transmitting power to a rotor arrangement of a separately excited electrical machine, comprising:

[0017] - a hollow rotor shaft;

[0018] - a primary arrangement;

[0019] - a secondary arrangement; and

[0020] - a locking element which fixes the secondary arrangement in a cylindrical part of the hollow rotor shaft.

[0021] The term "power transmission arrangement" describes an exciter or exciter of an electrical machine. The power transmission arrangement generally serves to induce electrical energy from power electronics into the rotor winding. The power transmission arrangement can be an exciter, for example, an inductive exciter, and is designed to transmit power to a rotor assembly of a separately excited electrical machine. The separately excited electrical machine can be an electric motor.

[0022] According to the invention, the power transmission arrangement initially comprises a hollow rotor shaft. The hollow shaft can, for example, be provided without a tapered end or bearing end, for example as a cylindrical hollow shaft. The cylindrical hollow shaft can be surrounded by a stator-side laminated core with stator-side windings or the stator. Furthermore, a primary arrangement is provided. The primary arrangement can be the primary side of an inductive transformer and can comprise a primary winding and a primary ferrite. The primary winding can be arranged rotationally fixed around the primary ferrite. The primary ferrite can be cylindrical. The primary ferrite can have a T-shaped cross-section.

[0023] Furthermore, the power transmission arrangement according to the invention has a secondary arrangement. The secondary arrangement can be the secondary side of an inductive transformer and can comprise a secondary winding and a secondary ferrite. The secondary arrangement can be cylindrical. The secondary arrangement can have a U-shaped cross-section.

[0024] According to the invention, the power transmission arrangement comprises a securing element which, among other things, can be configured to fix the secondary arrangement in a cylindrical part of the hollow rotor shaft or a cylindrical hollow shaft. The securing element can, for example, be cylindrically shaped and have a T-shaped cross-section, as well as an external thread on its outer diameter. An internal thread can be present on the inner circumference of the cylindrical hollow shaft in the area between the axially outer end of the hollow shaft and the desired position of the secondary side. By screwing the securing element into the hollow shaft, a secondary arrangement can, for example, be fixed in a functional position in the hollow rotor shaft.

[0025] The locking element can also be designed as a locking ring that is fitted into a groove on the inner circumference of the hollow shaft.

[0026] The secondary arrangement can be directly adjacent to the securing element according to the invention or it can be spaced from it by a separating element, for example a separating ring.

[0027] In one embodiment of the present invention, the power transmission assembly further comprises a support lance that is rotationally fixedly connected to the primary assembly. The support lance can be in the form of a bolt and can have a diameter of 3 to 15 mm. The length of the support lance can depend on the installation space of the electric machine and / or the length of the secondary assembly. In one embodiment, the support lance can be designed such that it is not connected to a machine housing.

[0028] The carrier lance can further be designed so that it has different diameters in longitudinal sections.

[0029] The primary assembly can be connected to the support lance. For example, the primary assembly can be secured to the support lance by a retaining ring. The retaining ring can be a nut. The connection can also be made by gluing or the like. There can be more than one connection and / or connection type between the primary assembly and the support unit.

[0030] In a further embodiment of the power transmission arrangement according to the invention, the support lance connected to the primary arrangement is connected to a bearing end of the hollow rotor shaft. A bearing end is, for example, a non-disposed side part of the hollow rotor shaft. The bearing end can be tapered and, for example, have a funnel-shaped cross-section. The bearing end can be made of the same material as the cylindrical hollow shaft / hollow rotor shaft.

[0031] The bearing end can be the side part of a hollow rotor shaft, with the bearing end tapering to provide space for the rotor bearing.

[0032] The connection between the support lance, which is connected to the primary assembly, and the bearing end can be created, for example, by a connecting element. Several different connecting elements can be present. The connecting element can be a bearing and a locking element, for example, a nut.

[0033] In a further embodiment, the support lance, which is connected to the primary assembly, is mounted inside the bearing end. The bearing end can provide a flat surface inside, which can represent a receiving or connecting plane to a part of the bearing that supports the support lance. The connection between the bearing and the bearing end can be an adhesive connection, a press connection, or the like. The connection between the bearing and the support lance can be an adhesive connection, a press connection, an axial clamp connection, or the like.

[0034] The bearing can be a roller bearing. The bearing can be a ball bearing. By mounting the support lance in the bearing end, the primary assembly, which is later fixed in the hollow rotor shaft, is protected from tilting, for example.

[0035] In a further embodiment, the support lance has a recess for routing cables. The recess can be configured, for example, as a groove or a bore through which the connections and / or cables can be routed.

[0036] In a further embodiment, the primary assembly is fixed in alignment with the secondary assembly. The primary assembly can be pushed into the secondary assembly using the support lance, so that the primary assembly and the secondary assembly are in their functional position. A functional position can, for example, be a defined air gap of 1 mm for the inductive transformer. The primary and secondary assemblies can be fixed in the desired alignment at another location in the power transmission assembly.

[0037] For example, according to another embodiment, fixing in such an aligned position can be achieved by connecting the bearing end to the cylindrical part of the hollow rotor shaft. This connection can be, for example, a press fit, a welded joint, or the like.

[0038] In a further embodiment, the securing element further fixes a rectifier unit in the cylindrical part of the hollow rotor shaft. The rectifier unit can be in contact with a protective circuit, which is also held in the hollow rotor shaft by means of the securing element according to the invention. In a further embodiment of the power transmission arrangement according to the invention, the hollow rotor shaft has a further securing element in a central section of the cylindrical part. The further securing element can serve, for example, to fix components of the power transmission arrangement integrated, mounted or fastened in the hollow rotor shaft on a side opposite the first, or the one, securing element. This opposite side can be located in a central section of the hollow rotor shaft. The central section is, for example, a middle section of the hollow rotor shaft.

[0039] The additional securing element can be in the form of a retaining ring. The additional securing element can be made of a flexible material, for example, an elastomeric plastic. The securing element can be made of a rigid material, for example, a metal, a metal alloy, carbon, a nanomaterial, a composite material, and the like.

[0040] Preferably, the additional securing element is made of steel. The additional securing element can also be designed in the form of an axial shoulder in an inner part of the hollow rotor shaft, which can serve as a stop.

[0041] In a further aspect, the present invention provides a method of assembling a power transmission assembly comprising:

[0042] - Providing the hollow rotor shaft;

[0043] - Attaching the second securing element in the central portion of the cylindrical area of ​​the hollow rotor shaft;

[0044] - Attaching the rectifier unit to the second fuse element;

[0045] - Attaching the secondary assembly to the rectifier assembly;

[0046] - Attaching the first securing element to an outer end of the cylindrical part of the hollow rotor shaft;

[0047] - Connecting the support lance to the primary assembly; - Connecting the support lance to the bearing end of the hollow rotor shaft, the connection between the support lance and the bearing end being mounted inside the bearing end;

[0048] - Joining the bearing end and the cylindrical part of the hollow rotor shaft; and

[0049] - Connecting the bearing end and the cylindrical part of the rotor hollow shaft.

[0050] In the method according to the invention, a hollow rotor shaft, for example, a cylindrical hollow rotor shaft, can first be provided. In an inner, central section, a second securing element, for example, in the form of a retaining ring, is first attached to this hollow rotor shaft, which secures the power transmission arrangement inside the hollow rotor shaft, for example, in a central section.

[0051] In a further process step, the rectifier unit can be attached to the second fuse element. This can also be provided with a protective arrangement and other isolating devices before the secondary arrangement is attached in the process step.

[0052] In the method according to the invention, the secondary arrangement is connected in a rotationally fixed manner to the cylindrical hollow rotor shaft, for example by inserting the first securing element into the cylindrical part of the hollow rotor shaft, wherein the securing element can be designed in such a way that no axial movement of the secondary arrangement is permitted.

[0053] In a further process step, the support lance can be connected to the primary assembly. The connection can be made using a retaining ring, such as a nut or the like, or it can be an adhesive or welded connection. The connection can be a non-rotatable connection.

[0054] In a further step of the method according to the invention, the support lance is connected to the bearing end. For example, the connection can be designed such that the support lance is fixed to the bearing assembly by means of a nut, with the bearing assembly being connected to the bearing end, thereby holding the support lance in the bearing end.

[0055] In a further step, the primary assembly and the secondary assembly of the power transmission assembly according to the invention can be brought together and aligned with each other. Alignment here means, for example, ensuring that the primary assembly and the secondary assembly are radially correctly aligned with each other, for example, to prevent the components from colliding during final assembly.

[0056] Axial displacement is eliminated by the design according to the invention, since the primary arrangement and the secondary arrangement can be fixed independently of each other in the rotor shaft.

[0057] Furthermore, the bearing arrangement provides effective protection of the primary arrangement against tilting of the primary arrangement during assembly, wherein the support lance does not have to be fixed, for example, to a housing of an electrical machine which has the power transmission arrangement according to the invention.

[0058] In a final process step, the primary assembly and the secondary assembly are connected, for example, in a functional layer. A functional layer can be a layer in which the primary assembly and the secondary assembly in the power transmission arrangement have a defined air gap between them.

[0059] The primary arrangement and the secondary arrangement can be preassembled independently of each other in the method according to the invention.

[0060] By fixing the secondary arrangement in the cylindrical part of a hollow rotor shaft and fixing the primary arrangement in the bearing end of the hollow rotor shaft according to the invention, a functional position, such as an air gap, can be preset, which does not change even during subsequent assembly in an electrical machine, whereby the components of the electrical machine are not damaged and low wear of the electrical machine can be ensured.

[0061] The (pre-)assembly of the secondary assembly and the (pre-)assembly of the primary assembly can be performed as parallel process steps. However, the process can also be designed so that the process steps are carried out sequentially, without requiring a specific sequence.

[0062] The primary and secondary assemblies can be pre-assembled or partially pre-assembled. Pre-assembled here means, on the one hand, the presence of a ferrite and winding, as well as a pre-assembly with other functional units of the power transmission assembly described herein.

[0063] In a further aspect, the present invention provides a rotor assembly comprising the power transmission assembly according to the invention.

[0064] In a further aspect, the present invention provides a separately excited electrical machine comprising the rotor arrangement.

[0065] In a further aspect, the present invention provides a vehicle comprising the separately excited electric machine.

[0066] By means of such a designed rotor and its assembly concept, as well as the method for assembling the power transmission arrangement presented here, it can be ensured that the primary side is held securely enough so that it is not damaged or damaged by any other part during handling and the manufacturing processes between insertion into the rotor shaft and installation of the rotor in the housing.

[0067] Furthermore, a rotor designed in this way and its assembly concept can ensure that the primary side of the transformer is positioned with sufficient accuracy relative to the secondary side during operation. Embodiments of the invention will now be described by way of example and with reference to the accompanying drawing, in which:

[0068] Fig. 1 schematically shows an embodiment of the power transmission arrangement according to the invention;

[0069] Fig. 2 schematically shows a further embodiment of the power transmission arrangement according to the invention;

[0070] Fig. 3 shows a cross section of an embodiment of the retaining ring according to the invention;

[0071] Fig. 4 schematically shows a further embodiment of the power arrangement according to the invention;

[0072] Fig. 5 schematically shows a rotor arrangement according to the invention; and Fig. 6 shows a block diagram of the method according to the invention.

[0073] Before referring to the embodiments in the figures, general statements are made about the power transmission arrangement according to the invention.

[0074] In inductive power transmission, as in the power transmission arrangement described here, an alternating current provided by the power electronics is transmitted contactlessly through an inductive (current / rotary) transmission device. Such an inductive transmission device can be a (e.g. rotationally symmetrical) transformer which comprises a primary arrangement and a secondary arrangement, wherein the primary arrangement comprises a primary ferrite core with associated primary windings and the secondary arrangement comprises a secondary ferrite core with associated secondary windings. The primary winding (coil) generates a magnetic field which is bundled by the ferrite core(s). The primary ferrite core and the secondary ferrite core are separated from one another by an air gap. As a rule, the primary arrangement is fixed in place in the electrical machine, e.g. on the housing, and the secondary arrangement, on the other hand, is rotatable, e.g.through a rotationally fixed connection to the rotor. The inductive transmission device allows an alternating current to be transmitted contactlessly from the primary winding of the primary assembly to the secondary winding of the secondary assembly. A rectifier board connected to the secondary winding taps the transmitted alternating current and converts it into direct current to power the rotor winding.

[0075] The power transmission unit typically comprises a primary assembly and a secondary assembly that are rotatable relative to one another. Both the primary assembly and the secondary assembly each comprise a ferrite and a magnetic coil arranged around it. A design that has proven successful so far is one in which the cylindrical primary assembly is aligned axially within the cylindrical secondary assembly. The two magnetic coils are arranged overlapping between them. The primary assembly is firmly connected to the housing, and the secondary assembly is non-rotatably connected to the rotor. The circumferential air gap between the ferrite of the primary assembly and the ferrite of the secondary assembly forms the transmission surface and is crucial for efficient power transmission.

[0076] The air gap is formed at each end section, and the overlapping coils are arranged in the center section. The air gap should be as small as possible in the radial direction, for example, less than 1 mm. However, the air gap is limited downwards, taking into account tolerances and play. For the best possible efficiency, the primary and secondary arrangements must be aligned as precisely as possible in the axial direction.

[0077] Returning to the embodiments of the present invention, Fig. 1 shows an embodiment of the power transmission arrangement (10) according to the invention. A first securing element (4) is mounted in a hollow rotor shaft (7a), which, for example, has a T-shaped cross-section, as can be seen in Fig. 3. The securing element (4) fixes a secondary arrangement (2), consisting of a secondary ferrite (2a) and secondary windings (2b). The secondary arrangement (2) according to the embodiment of Fig. 1 is followed by a rectifier unit (9), which can further be spaced from the secondary arrangement by a separating element (not shown here). A further securing element (8) fixes the power transmission arrangement in the direction of the interior of the hollow shaft.

[0078] Figure 2 shows a further embodiment of the power transmission arrangement (10) according to the invention. Here, a primary arrangement (1) comprising a primary ferrite (1a) and primary windings (1b) is connected to a carrier lance (3). The connection can be established, for example, by a nut (5), which securely fastens the primary arrangement (1) to the carrier lance (3).

[0079] Figure 2 shows a further embodiment in which the support lance (3), which is connected to the primary assembly (1), is connected to a bearing end (7b) via a bearing assembly (6). The support lance (3) can be axially attached to the bearing assembly (6). This protects it from tilting during the subsequent assembly of a rotor or the power transmission assembly (10) of a rotor of an electrical machine (100).

[0080] Fig. 4 shows a further embodiment of the power transmission arrangement (10) according to the invention, in which the bearing end (7b), which is connected to the support lance (3), which in turn is connected to the primary arrangement (1), is aligned on the cylindrical hollow rotor shaft (7a), wherein the alignment can take place in such a way that, for example, in an alignment area (16), the primary arrangement (1) is brought towards the secondary arrangement (2) and positioned in the radial direction (arrow directions), before it is positioned axially in a functional position, e.g. in a position in which the primary (1) and secondary arrangement (2) have a previously defined air gap from one another.

[0081] Such a functional position is depicted in the exemplary embodiment of Fig. 5, which schematically shows an electrical machine (100) having the power transmission arrangement (10). In the line arrangement (10) of Fig. 5, the primary arrangement (1) and the secondary arrangement (2) are fixed or mounted by connecting the cylindrical hollow shaft (7a) to the bearing end (7b) in a position in which an air gap (15) is maintained between the primary (1) and secondary arrangements (2).

[0082] The air gap (15) shown in Fig. 5 can be adjusted in the power transmission arrangement (10) before assembly in an electrical machine (100), since the secondary arrangement (2) and the primary arrangement (1) are each fixed independently of one another in the power transmission arrangement (10).

[0083] This also provides the possibility of pre-assembling the primary assembly (1) and the secondary assembly (2) with corresponding rotor components.

[0084] In addition, the primary arrangement (1) is supported by the bearing arrangement (6) independently of the rotor wall of the hollow rotor shaft (7), which can be composed of the cylindrical part (7a) and the bearing end (7b) and which is connected to the secondary arrangement (2).

[0085] Since the secondary arrangement (2) is held individually by the primary arrangement (1) in the rotor shaft by the securing element (4), the air gap (15) can be maintained even with axial play.

[0086] The support lance (3) does not have to be connected to the housing of an electrical machine (100). The electrical machine (100) can further comprise an outer bearing arrangement (13) at the bearing end (7b) of the power transmission arrangement (10) for supporting the latter in the electrical machine. The power transmission arrangement (10) is surrounded here by a stator arrangement (11) comprising a stator core with a winding (12). The arrangement thus designed in Fig. 5 is further surrounded by a housing (14).

[0087] Fig. 6 shows a block diagram of the method according to the invention for assembling a power transmission arrangement (10).

[0088] In method step S1, a hollow rotor shaft, for example, a cylindrical hollow rotor shaft (7a), is first provided. A second securing element (8) is mounted in an inner, central section, which is intended to secure the power transmission arrangement (10) inside the hollow rotor shaft (7a), for example, in a central section (S1).

[0089] In process step S3, the rectifier unit (9) is attached to the fuse element (8). This unit can also be provided with a protective arrangement and other isolating arrangements (not shown) before the secondary arrangement (2) is attached in process step S4.

[0090] In method step S5, the secondary arrangement (2) is connected in a rotationally fixed manner to the cylindrical hollow rotor shaft (7a) by inserting the first securing element (4) into the cylindrical part of the hollow rotor shaft (7a), wherein the securing element (4) is designed in such a way that no axial movement of the secondary arrangement (2) is permitted.

[0091] In a further process step S6, the support lance (3) is connected to the primary assembly (1). The connection can be made by a retaining ring such as a nut (5), or it can be an adhesive or welded connection. The connection is a rotationally fixed connection.

[0092] In method step S7, the support lance (3) is connected to the bearing end (7b). For example, the connection can be designed such that the support lance is fixed to a bearing assembly (6) by means of a nut (5), the bearing assembly (6) being connected to the bearing end (7b), thereby holding the support lance (3) in the bearing end (7a).

[0093] In method step S8, the primary arrangement (1) and the secondary arrangement (2) of the power transmission arrangement are brought together and aligned with one another. In this case, it is ensured in an alignment region (16), for example, that the primary arrangement (1) and the secondary arrangement (2) are radially correctly positioned relative to one another (arrow directions in Fig. 4) in order to prevent the components from striking one another during final assembly. In a final method step S9, the primary arrangement (1) and the secondary arrangement (2) are connected in a functional position. A functional position can be a position in which the primary arrangement (1) and the secondary arrangement (2) in the power transmission arrangement have the air gap (15).

[0094] The primary assembly (1) can be preassembled independently of the secondary assembly (2). By fixing the secondary assembly (2) in the cylindrical part (7a) of a hollow rotor shaft (7) and fixing the primary assembly (1) in the bearing end (7a) of the hollow rotor shaft according to the invention, a functional position, such as an air gap (15), can be preset. This air gap does not change even during subsequent integration into an electrical machine (100), thus preventing damage to the components of the electrical machine and ensuring low wear of the electrical machine.

[0095] In Fig. 6, process steps S1 to S5 of the (pre-)assembly of the secondary assembly (2) and process steps S6 and S7 of the (pre-)assembly of the primary assembly (1) are shown as parallel process steps. However, the process can also be designed so that the process steps are carried out sequentially, without requiring a specific sequence.

[0096] Reference symbol

[0097] Primary arrangement a primary ferrite b primary windings

[0098] Secondary arrangement a Secondary ferrite b Secondary windings

[0099] Carrier lance

[0100] securing element

[0101] Nut / lock washer

[0102] Bearing arrangement

[0103] Hollow rotor shaft a cylindrical part (of the hollow rotor shaft) b bearing end inner / further / second securing element

[0104] Rectifier unit 0 Power transmission arrangement 1 Stator 2 Laminated core with windings (stator side) 3 Rotor bearing 4 Housing 5 Air gap 6 Alignment area 00 Electrical machine

Claims

Patent claims 1. Power transmission arrangement (10), in particular an inductive power transmission arrangement (10), for transmitting power to a rotor arrangement of a separately excited electrical machine (100), comprising: - a hollow rotor shaft (7); - a primary arrangement (1); - a secondary arrangement (2); and - a securing element (4) which fixes the secondary arrangement (2) in a cylindrical part (7a) of the hollow rotor shaft (7).

2. Power transmission arrangement (10) according to claim 1, further comprising a support lance (3) connected to the primary arrangement (1).

3. Power transmission arrangement (10) according to claim 2, wherein the support lance (3) connected to the primary arrangement (1) is connected to a bearing end (7b) of the hollow rotor shaft (7).

4. Power transmission arrangement (10) according to claim 3, wherein the support lance (3) is mounted inside the bearing end (7b).

5. Power transmission arrangement (10) according to one of claims 2 to 4, wherein the support lance (3) has a recess for cable routing.

6. Power transmission arrangement (10) according to one of the preceding claims, wherein the primary arrangement (1) is fixed in alignment with the secondary arrangement (2).

7. Power transmission arrangement (10) according to one of the preceding claims, wherein the bearing end (7a) is connected to the cylindrical part (7b) of the hollow rotor shaft (7).

8. Power transmission arrangement (10) according to claim 1, wherein the securing element (4) further fixes a rectifier unit (9) in the cylindrical part (7a) of the hollow rotor shaft (7).

9. Power transmission arrangement (10) according to one of the preceding claims, wherein the hollow rotor shaft (7) has a further securing element (8) in a central portion of the cylindrical part (7a).

10. A method for assembling a power transmission arrangement (10) according to any one of the preceding claims, comprising: - Providing the hollow rotor shaft (7); - attaching the second securing element (8) in the central portion of the cylindrical region (7a) of the hollow rotor shaft (7); - Attaching the rectifier unit (9) to the second fuse element (8); - Attaching the secondary assembly (2) to the rectifier unit (9); - attaching the first securing element (4) to an outer end of the cylindrical part (7a) of the hollow rotor shaft (7); - connecting the carrier lance (3) to the primary assembly (1); - connecting the support lance (3) to the bearing end (7b) of the hollow rotor shaft (7), wherein the connection between the support lance (3) and the bearing end (7b) is mounted inside the bearing end (7b); - Bringing the bearing end (7b) and the cylindrical part (7a) of the hollow rotor shaft (7) together in a functional position; and - Connecting the bearing end (7b) and the cylindrical part (7a) of the hollow rotor shaft (7).

11. Rotor assembly comprising the power transmission assembly (10) according to one of claims 1 to 9.

12. A separately excited electrical machine (100) comprising the rotor assembly according to claim 11.

13. A vehicle comprising the separately excited electric machine (100) according to claim 12.

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