Power transmission arrangement for transmitting power to a rotor arrangement of a separately excited electrical machine, method for installing a power transmission arrangement, rotor arrangement comprising the power transmission arrangement, and separately excited electrical machine comprising the rotor arrangement

Abstract

The present invention relates to a power transmission arrangement (10), in particular an inductive power transmission arrangement (10), and to a rotary transformer, for transmitting power to a rotor arrangement of a separately excited electrical machine (20), comprising a hollow rotor shaft (11), a primary arrangement (1), a carrier lance (3) connected to the primary arrangement (1), and a bearing arrangement (4) that mounts the carrier lance (3) connected to the primary arrangement (1) in a cylindrical part of the hollow shaft (11).

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 preassembling a power transmission arrangement according to claim 7, a method for preassembling a rotor arrangement according to claim 8, a method for assembling a separately excited electrical machine according to claim 9, and a motor vehicle according to claim 11.

[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 carrier lance connected to the primary assembly; and

[0020] - a bearing arrangement that supports the carrier lance connected to the primary assembly in a cylindrical part of the hollow 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] A hollow rotor shaft here refers, for example, to a cylindrically shaped part of a hollow shaft without a bearing end, into which the inductive transformer or power transmission assembly can be inserted. The power transmission assembly according to the invention initially comprises a support lance connected to a primary assembly. The connection is a rotationally fixed connection. The support lance can be in the form of a bolt and can have a diameter of 3 to 15 mm.

[0023] The carrier lance can further be designed so that it has different diameters in longitudinal sections.

[0024] The length of the support lance can depend on the installation space of the electric machine and / or the length of the primary assembly. The support lance can be designed so that it can be connected to a machine housing of the electric machine.

[0025] 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, welding, and the like. There can be more than one connection and / or connection type between the primary assembly and the support unit.

[0026] 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 in a rotationally fixed manner around the primary ferrite. The primary ferrite can be cylindrical. The primary ferrite can have a T-shaped cross-section.

[0027] The power transmission arrangement according to the invention further comprises a bearing arrangement which is connected to the support lance. The bearing arrangement is designed, for example, such that an inner region of the bearing arrangement is connected to the support lance and an outer region is connected to an inner diameter of a section of the cylindrical part of the hollow rotor shaft. The connection can be direct, for example by gluing, but a further element can also be arranged between the inner diameter of the hollow shaft and the outer region of the bearing arrangement and connected to each other. In one exemplary embodiment, the bearing arrangement comprises two ball bearings positioned against one another. The bearing arrangement can be designed such that a preloaded O-arrangement is formed from the two ball bearings by virtue of the fact that a preloaded O-arrangement is formed between the segments of the outer region of the bearing arrangement, orA spacer is located between the outer rings of the ball bearings, while the inner area of ​​the bearing assembly, or the inner rings of the ball bearings, is / are connected to the support lance, whereby the inner rings are pressed together under preload. This can, for example, result in a particularly compact design and high flexural rigidity of the bearing assembly. In this way, a preassembled bearing cartridge can be produced, for example, by fitting the bearing assembly into a sleeve.

[0028] A preloaded bearing as described above has greater tilt stability than a single ball bearing, which, in this embodiment of the invention, ensures that the primary assembly and the secondary assembly do not touch each other, thus preventing damage. Furthermore, the bearing assembly according to the invention can ensure extremely smooth running during operation.

[0029] As already described above, in one embodiment, the ball bearings are separated by a spacer washer mounted between the outer rings of the ball bearings. The spacer can contribute to increasing the flexural rigidity of the bearing assembly.

[0030] In a further embodiment, the carrier lance is connected to an inner ring of the bearing arrangement.

[0031] According to a further embodiment, the support lance can have 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 are routed. In a further embodiment, the power transmission arrangement can have a spring, wherein the spring is attached to the bearing arrangement. Depending on the design of the bearing arrangement, the spring can be attached to an axially left or axially right end of the bearing arrangement.

[0032] In a further embodiment, the power transmission arrangement has a sleeve that is attached to the bearing arrangement. The sleeve can, for example, space the bearing arrangement from the inner diameter of the hollow rotor shaft. Furthermore, the sleeve can be designed such that it spaces the bearing arrangement from the secondary arrangement. This allows, for example, smaller bearings to be used that are better suited to the design of the rotor or the desired speeds. Furthermore, the assembly of the power transmission arrangement can be made easier. Furthermore, a pre-assembled bearing cartridge as described above can be obtained by fitting the preloaded bearing arrangement into the sleeve described here.

[0033] For example, the carrier lance can be inserted into a pre-assembled bearing cartridge that includes the sleeve and the ball bearings. The pre-assembled bearing cartridge can be pre-mounted on the carrier lance together with the primary ferrite core. According to one embodiment, the inner rings can be pressed against each other via a wave spring acting as a bearing spring between a retaining ring and one of the inner rings, thus elastically adjusting or pre-tensioning them in an O-arrangement.

[0034] In a further embodiment, the carrier lance is preassembled with the primary assembly and the bearing assembly. This can be done, for example, in a manner described above.

[0035] In a further embodiment, the power transmission arrangement further comprises a secondary arrangement and a rectifier unit. The secondary arrangement can be the secondary side of the inductive transformer or the power transmission arrangement 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. The rectifier unit can be in contact with a protection circuit.

[0036] In another aspect, the present invention provides methods of assembling a power transmission assembly comprising:

[0037] - Providing a storage end;

[0038] - Providing the hollow shaft;

[0039] - Providing the support lance, wherein the support lance is connected to the primary assembly and the bearing assembly;

[0040] - Fitting a retaining ring inside the cylindrical part of the hollow shaft;

[0041] - Attaching the rectifier unit to the retaining ring

[0042] - Attaching the secondary assembly to the rectifier unit;

[0043] - Attaching the spring to the secondary assembly;

[0044] - Attaching the provided support lance with primary assembly and bearing assembly to the spring;

[0045] - Attaching a retaining ring to an outer end of the cylindrical part of the hollow shaft; and

[0046] - Joining the hollow shaft to the bearing end, with one end of the support lance protruding from the bearing end.

[0047] Instead of a retaining ring, a shoulder can also be provided on the inner diameter of the hollow shaft as an axial reduction.

[0048] A bearing end is, for example, a side part of the hollow rotor shaft that is not or not yet provided.

[0049] In a further aspect, the present invention provides a rotor assembly comprising a power transmission assembly according to the invention.

[0050] By means of the power transmission arrangement according to the invention, all electronic components of a rotor arrangement, such as the rectifier unit of an inductively excited rotor as well as the primary arrangement and the secondary arrangement of the inductive transformer, can be pre-assembled in a cylindrical part of the hollow rotor shaft before the hollow rotor shaft is provided with, for example, a funnel-shaped bearing end.

[0051] The primary assembly is mounted in the cylindrical part of the hollow rotor shaft by the bearing assembly, ensuring zero play. In one embodiment of the present invention, the primary assembly of the power transmission assembly can be provided as a preassembled component. The preassembled component can comprise a support lance connected to the primary assembly and a bearing assembly.

[0052] In a further aspect, the present invention provides an electric machine comprising the rotor arrangement according to the invention. The electric machine is, for example, a separately excited electric machine.

[0053] When mounting the rotor assembly in the housing of an electric machine, the support lance, which is connected to the primary assembly, can be connected to the housing of the electric machine in such a way that a defined, tangential relative movement of the support lance is permitted. The permitted relative movement is a maximum of +1-2 degrees.

[0054] The permitted relative rotational movement of the support lance relative to the housing of the electric machine can be achieved, for example, by making the support lance semicircular rather than round at the housing end, and by providing the housing with the corresponding negative contour, which secures the support lance with minimal play. By allowing minimal play, static overdetermination of the power transmission arrangement can be avoided.

[0055] Since the power transmission arrangement according to the invention is mounted on the primary side (i.e. its primary arrangement) by means of the bearing arrangement in the rotor shaft, it is in principle possible to use any coupling known from the prior art for connecting the support lance to the machine housing, wherein the coupling method can allow compensation of axial misalignments, angular errors and axial movements in order to avoid a rigid coupling with the machine housing and thus a static overdetermination.

[0056] In one embodiment, the support lance of the power transmission assembly can be integrated into the equipotential bonding system of the electrical machine. Furthermore, when installed in the system housing of an electrical machine, the power transmission assembly can have a sealant at the connection point to the electrical machine, as well as integration into the equipotential bonding system. This can, for example, prevent a current flow in the bearing assembly of the power transmission assembly of the inductive exciter.

[0057] In a further aspect, the present invention comprises a vehicle having the electric machine according to the invention.

[0058] By means of a rotor arrangement according to the invention and the method presented here for assembling the power transmission arrangement for a rotor arrangement for an electrical machine, it can be ensured that the primary side is held securely enough so that it is not damaged or damages another part during handling and the manufacturing processes between insertion into the rotor shaft and installation of the rotor in the housing.

[0059] 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.

[0060] Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0061] Fig. 1 schematically shows an embodiment of the power transmission arrangement according to the invention;

[0062] Fig. 2 schematically shows a further embodiment of the power transmission arrangement according to the invention;

[0063] Fig. 3 shows schematically an electrical machine according to the invention; Fig. 4 shows schematically a further embodiment of the power transmission arrangement according to the invention; and

[0064] Fig. 5 shows a block diagram of the method according to the invention.

[0065] Before referring to the embodiments in the figures, general statements are made about the power transmission arrangement according to the invention.

[0066] 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 non-rotatable connection with the rotor.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] Returning to the embodiments of the present invention, Fig. 1 shows an embodiment of the power transmission arrangement (10) according to the invention. A retaining ring (12) is attached to an outer end of the cylindrical part of a hollow rotor shaft (11). A primary arrangement (1) is connected to a support lance (3). The connection can be made by clamping with a nut (5). The support lance (3) is further connected to a bearing arrangement (4). The bearing arrangement in Fig. 1 consists of two ball bearings (4a, 4b) which form a preloaded O-arrangement as a bearing area (6) for the support lance (3). In the bearing area (6), a spacer washer (7) can be located between the outer rings (41a, 41b) of the ball bearings (4a, 4b). The inner rings (42a, 42b) of the ball bearings (4a, 4b) are connected to the support lance (3) in a rotationally fixed manner, for example by gluing.

[0071] The outer rings (41a, 41b) of the ball bearings (4a, 4b) can be connected in a rotationally fixed manner to the inner wall of the cylindrical part of the hollow rotor shaft (11), for example by gluing. Alternatively, this can be achieved by a press fit between the aforementioned parts. The bonding of the components of the bearing area (6), in particular the inner rings (42a, 42b) on the support lance (3), can be carried out under preload, which can result in a compact design of the bearing area that simultaneously exhibits high flexural rigidity. Alternatively, the inner rings (42a, 42b) can be axially clamped between, for example, an axial stop on the support lance (3) and a retaining ring (26) by means of a bearing spring (27), and the spring force can be applied as preload.

[0072] The power transmission arrangement (10) of Fig. 1 further comprises a spring (8) which is mounted between the second ball bearing (4b) and the secondary arrangement (2). The spring (8) is located between the outer ring (41b) of the ball bearing (4b) and the secondary ferrite (2a) of the secondary arrangement (2). The spring (8) is designed, for example, to compensate for component tolerances in the axial direction. In the embodiment of Fig. 1, the secondary arrangement (2) is followed by a rectifier unit (9). By means of a further retaining ring (12), the components of the power transmission arrangement (10) described in the embodiment of Fig. 1 are fixed in the cylindrical part of the hollow rotor shaft (11).

[0073] In Fig. 1, a bore (13) is also shown on the support lance (3), with which the support lance (3) is provided for cable guidance.

[0074] The embodiment of the power transmission assembly (10) depicted in Fig. 2 is connected to a bearing end (14) of the hollow rotor shaft in addition to the embodiment depicted in Fig. 1. The connection may be a welded joint.

[0075] The support lance (3) in Fig. 2 is designed such that it protrudes from the bearing end (14). The protruding end of the support lance (3) is provided with a protective cap (15) to protect it from damage during further production steps, which can protrude into the interior of the bearing end (14). There are also embodiments (not shown) in which the protective cap (15) protrudes beyond the end of the bearing end (14). Fig. 3 shows an electrical machine (20) according to the invention, in which the power transmission arrangement (10) is installed. The cylindrical part of the hollow rotor shaft (11) is surrounded by a stator (16) and the stator-side laminated core with winding (17). The rotor arrangement with the power transmission arrangement (10) is mounted in the housing (18) of the electrical machine (20) by the rotor bearing (19). The housing (18) of the electrical machine (20) has an opening (21) through which the carrier lance (3) is guided.The opening (21) can be a negative contour of the support lance (3). The support lance (3) can have a semicircular shape. The opening is provided with a seal (22). The housing (18) has a cable opening (23) through which the cables of the power transmission arrangement (10) are routed. The support lance (3) and the housing (18) are integrated into a potential equalization system (24).

[0076] Fig. 4 shows a further embodiment of the power transmission arrangement (10) according to the invention. Here, the primary arrangement (1) is pre-assembled together with the bearing arrangement (4) on the support lance (3) before the latter is mounted in the hollow rotor shaft (11). A sleeve (25) is attached to the bearing arrangement (4), which is glued, for example, to the outer rings (41a, 41b) of the bearing arrangement. On the side of the bearing arrangement (4) on which the primary arrangement is located, the sleeve (25) has a projection that partially encloses the outer ring (41b). In this way, the spring (8) can be omitted for spacing and tolerance compensation of the bearing arrangement (4) to the secondary ferrite (2b).

[0077] In the embodiment shown here, a retaining ring (26) is also attached to the support lance. A bearing spring (27) is mounted between the retaining ring (26) and the inner ring (42a) to compensate for tolerances and elastically adjust the two bearings in an O-arrangement.

[0078] If the power transmission assembly (10) shown in Fig. 4 is installed in a hollow rotor shaft (11), the spring (8) is located on the side of the bearing end (14) on the bearing assembly (4) (not shown). Fig. 5 shows the inventive method for assembling the power transmission assembly (10) in the form of a block diagram.

[0079] The method according to the invention can be characterized in that all components of the power transmission arrangement are mounted in the cylindrical part of the hollow shaft (11) before it is provided with a bearing end (14).

[0080] In the method according to the invention, in step S1 the support lance (3) is first connected to the primary assembly (1) and the bearing assembly (4). In a further step S2, a hollow rotor shaft (11) or its cylindrical part is provided. A retaining ring (12) is mounted in this on an inner central section (S3). The rectifier unit is attached to the retaining ring (12) before the secondary assembly (2) is inserted into the hollow shaft in method step S4. The support lance (3) from method step S1 is attached to the secondary assembly (2) (S5), wherein a spring (8) is attached to the bearing assembly (4), for example between the bearing assembly (4) and the secondary assembly, in order to protect the primary assembly from striking the secondary assembly (2) or to space it from the bearing assembly with installation space tolerance.In process step S6, the components in the hollow rotor shaft (11) are secured to an outer end of the cylindrical part using another retaining ring (12). In process step S8, the hollow rotor shaft from process step S6 is joined to the bearing end (14) provided in S7, e.g., by welding.

[0081] Reference symbol

[0082] Primary arrangement

[0083] Secondary arrangement a secondary ferrite

[0084] Carrier lance

[0085] Bearing arrangement a, 4b ball bearings

[0086] Mother

[0087] storage area

[0088] spacer

[0089] Feather

[0090] Rectifier unit 0 Power transmission arrangement 1 Hollow rotor shaft (cylindrical part) 2 Retaining ring 3 Groove 4 Bearing end 5 Protective cap 6 Stator 7 Stator-side laminated core with winding 8 Housing 9 Rotor bearing 0 Electrical machine 1 Opening 2 Seal 3 Cable opening 4 Potential equalization 5 Sleeve 6 Retaining ring 7 Bearing spring 1a, 41b Outer ring ball bearing 2a, 42b Inner ring ball bearing

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 (20), comprising: - a hollow rotor shaft (11); - a primary arrangement (1); - a carrier lance (3) connected to the primary assembly (1); and - a bearing arrangement (4) which supports the carrier lance (3) connected to the primary arrangement (1) in a cylindrical part of the hollow shaft (11).

2. Power transmission arrangement (10) according to claim 1, wherein the bearing arrangement (4) comprises two ball bearings (4a, 4b) positioned against one another.

3. Power transmission arrangement (10) according to claim 2, wherein the ball bearings (4a, 4b) are separated by a spacer disc (7) which is attached to an outer ring (41a, 41b) of the ball bearings (4a, 4b).

4. Power transmission arrangement (10) according to one of the preceding claims, wherein the carrier lance (3) is connected to an inner ring (42a, 42b) of the bearing arrangement (4).

5. Power transmission arrangement (10) according to one of the preceding claims, wherein the support lance (3) has a bore or recess (13) for cable routing.

6. Power transmission arrangement (10) according to one of the preceding claims, further comprising a spring (8), wherein the spring (8) is attached to the bearing arrangement (4).

7. Power transmission assembly (10) according to any one of the preceding claims, further comprising a sleeve (25) attached to the bearing assembly (4).

8. Power transmission arrangement (10) according to one of the preceding claims, wherein the support lance (3) is pre-assembled with the primary arrangement (1) and the bearing arrangement (4).

9. Power transmission arrangement (10) according to one of the preceding claims, further comprising: - a secondary arrangement (2); and - a rectifier unit (9).

10. A method for assembling a power transmission arrangement (10) according to one of claims 1 to 9, comprising: - Providing a storage end; - Providing the hollow shaft; - Providing the support lance, wherein the support lance is connected to the primary assembly and the bearing assembly; - Fitting a retaining ring inside the cylindrical part of the hollow shaft; - Attaching the rectifier unit to the retaining ring - Attaching the secondary assembly to the rectifier unit; - Attaching the spring to the secondary assembly; - Attaching the provided support lance with primary assembly and bearing assembly to the spring; - Attaching a retaining ring to an outer end of the cylindrical part of the hollow shaft; and - Joining the hollow shaft to the bearing end, with one end of the support lance protruding from the bearing end.

11. Rotor comprising a power transmission arrangement (10) according to one of the preceding claims.

12. An electric machine (20) comprising the rotor according to claim 11.

13. Electrical machine (20) according to claim 12, wherein the carrier lance (3) is integrated into the potential equalization (24) of the electrical machine (20).

14. A vehicle comprising the electric machine (20) according to one of claims 12 and 13.

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