Rotor assembly, and method for mounting the rotor assembly of a separately excited electric machine of a vehicle

Abstract

The invention relates to a rotor assembly having a rotor shaft (1), which is in the form of a hollow shaft, for a separately excited electric machine (2), wherein an axially insertable inductive transmission device (4) can be arranged inside the rotor shaft (1), and at least one rotor winding can be arranged on the outer circumference of the rotor shaft (1), wherein a contacting arrangement is provided for electrically connecting the inductive transmission device (4) and the rotor winding, wherein the contacting arrangement is formed by a contact element (5, 5A) fastened in a radial shaft through-passage of the rotor shaft (1), and wherein the contact element (5, 5A) has, at an end near the transmission device (8), a first axially oriented contact region (6) for electrical connection to the transmission device (8) and, at an end near the outer circumference of the rotor shaft (1), a second contact region (7) for electrical connection to the rotor winding. The invention also relates to a separately excited electric machine (2) comprising a rotor assembly and to a vehicle (3) comprising at least one separately excited electric machine (2).

Description

[0001] ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12

[0002] Rotor arrangement and method for mounting the rotor arrangement of a separately excited electric machine of a vehicle

[0003] The present invention relates to a rotor arrangement with a rotor shaft designed as a hollow shaft for a separately excited electric machine according to the type defined in more detail in the preamble of claim 1. The invention further relates to a method for assembling a rotor arrangement, a separately excited electric machine with a rotor arrangement, and a vehicle with a separately excited electric machine.

[0004] For example, a rotor arrangement for a separately excited synchronous machine is known from publication DE 102022207340 B3. The known rotor arrangement comprises a rotor shaft designed as a hollow shaft, which carries at least one excitation winding or rotor winding on its outer circumference by means of a rotor lamination stack. Inside the hollow rotor shaft, an inductive transmission device is arranged for the contactless inductive transmission of a current required for generating a rotor field to the at least one rotor winding. In order to electrically connect the rotor winding to the transmission device arranged inside the rotor shaft, a terminal socket is provided on the transmission device.The transmission device is arranged inside the rotor shaft such that the connection socket is oriented radially outwards in order to electrically connect the rotor windings to be subsequently mounted with the transmission device already arranged inside. For this purpose, the rotor winding connection is connected to the radially outward-projecting connection socket of the transmission device to establish an electrical connection between the transmission unit and the rotor winding.

[0005] However, it has been shown that during the assembly or insertion of the rotor winding, very high temperatures occur due to the hardening of the potting compound, which can damage the electronic components of the transmission device located inside the rotor shaft. Furthermore, the radially outward protruding position of the connection socket results in undesirable limitations regarding the ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12

[0006] Positioning the rotor winding to electrically connect it to the connection socket of the transmission device.

[0007] The present invention is based on the objective of proposing a rotor arrangement and a method for mounting the rotor arrangement, as well as a separately excited electric machine with the rotor arrangement and a vehicle with the separately excited electric machine, in which an improved, more variable electrical connection between the transmission unit and the rotor winding is realized.

[0008] This problem is solved according to the invention by the features of the subject matter of claims 1, 12, 13, and 14. Advantageous and claimed further developments are described in the dependent claims, the description, and the drawings.

[0009] The problem underlying the invention is solved by a rotor arrangement with a rotor shaft designed as a hollow shaft for a separately excited electric machine, wherein an axially insertable inductive transmission device and at least one rotor winding can be arranged inside the rotor shaft, and wherein a contact is provided for electrically connecting the inductive transmission device and the rotor windings. To establish the electrical connection, orTo further improve and make the contacting more variable, it is provided that at least one contacting element is provided as contacting, fixed in a radial shaft passage or the like of the rotor shaft, wherein the contacting element has at one end facing the transmission device a first contact area axially aligned with respect to the rotor shaft for electrical connection with the transmission device and at one end facing the outer circumference of the rotor shaft or the rotor winding a second contact area for electrical connection with the rotor winding.

[0010] In this way, the intended contacting element in the proposed rotor arrangement achieves a particularly simple and variable electrical connection between the transmission device and the rotor windings, because ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12

[0011] Contacting is possible, for example, independently of the assembly sequence. Due to the axial orientation of the first contact area facing the transmission device, blind joining is advantageously enabled when the transmission unit is axially inserted into the interior of the rotor shaft, even if the rotor winding is already mounted and potted on the rotor shaft. Because of the contact element provided in a shaft passage of the rotor shaft, the mounted rotor winding can be variably connected to the second contact area of ​​the contact element without any further process – e.g., by welding, soldering, crimping, or similar methods.

[0012] To maintain the necessary insulation distances at the contacting element in the proposed rotor arrangement, the contacting element is designed as a stamped grid with a plastic overmolding or similar coating. In this way, the electrical conductivity can be achieved through the stamped grid in a design-flexible and cost-effective manner, while the plastic overmolding provides the necessary air and creepage distances.

[0013] Within the scope of the present invention, it can be provided, for example, that the stamped grid has an L-shape or the like, wherein the first contact area is assigned to one end of the shorter section of the L-shape and the second contact area to one end of the longer section of the L-shape. Due to the selected L-shape, the axial alignment of the first contact area is easily achieved with the possibility of tolerance compensation for sufficient contact overlap, and a radial alignment of the second contact area is created, for example, to also provide variable contact for the rotor winding. Furthermore, the individually alignable contact areas are easily electrically interconnected via the stamped grid.

[0014] A further possible embodiment of the present invention can be realized by having the stamped grid have an L-shape only in sections, wherein the first contact area is assigned to the end of the shorter section of the L-shape, and wherein at least one [ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12]

[0015] An angled additional section is connected, with the axially aligned second contact area being provided at the end of the last additional section. In this way, both the first and second contact areas can be axially aligned to create a particularly flexible connection area for the electrical connection of the rotor winding. Thus, by using additional sections as needed, any desired position on the rotor shaft can be achieved for connecting the intended rotor windings to the transmission device. For example, it is also conceivable that two additional sections extending in opposite directions could be connected to the long end of the L-shape, allowing rotor windings to be connected on both sides.It is also conceivable to have several additional sections in succession in order to connect a winding connection that is axially further away to the transmission device via the contacting element.

[0016] In order to provide guidance and mechanical stabilization of the contacting element in the proposed rotor arrangement, at least one or more of the additional sections can be supported, at least section by section, in an axially running groove of the rotor shaft.

[0017] To ensure sufficient attachment of the contact element to the radial shaft passage of the rotor shaft, the outer shape of the plastic overmolding of the contact element is designed to form a circumferential flange collar or similar feature for radial force support in the area of ​​the shaft passage. This provides a structurally simple way to support the contact element against the centrifugal forces acting on the rotor shaft.

[0018] The plastic overmolding of the contact element of the proposed rotor arrangement and the shaft feedthrough have corresponding reference surfaces for the angular alignment of the contact element on the rotor shaft. The reference surfaces formed by the appropriately shaped plastic overmolding enable blind insertion or blind joining of the transmission device mounted after the rotor winding has been installed, since the position of the connection socket of the transmission device in relation to the first contact area of ​​the contact element is

[0019] This is ensured during the axial insertion of the transmission unit. The reference surfaces thus guarantee that the transmission device is mounted only in a predetermined angular position, so that the electrical connection between the transmission device and the contacting element is virtually automatically ensured.

[0020] To ensure sufficient insulation of the contact element from the metallic rotor shaft, the dimensions of the plastic indentation are selected to meet the required clearance and creepage distances. The clearance is defined as the shortest distance in air between two conductive parts. The creepage distance is defined as the shortest distance along the surface of an insulating material between two conductive parts.

[0021] Preferably, the first axially aligned contact area and / or the second contact area of ​​the contacting element of the proposed rotor arrangement are each designed as a detachable plug connection or the like. This not only provides a variable, simple electrical connection between the rotor winding and the transmission unit, but also makes this electrical connection detachable, thus enabling the transmission unit to be replaced very easily.

[0022] For example, the connector can be designed as a flat plug, contact blade, or similar device projecting axially from the contacting element at the first contact area. The axial length of the flat plug can compensate for corresponding axial tolerances, ensuring a reliable contact between the contacting element and, for example, a socket on the transmission device.

[0023] To ensure a blind connection between the contacting device and the first contact area of ​​the contacting element during axial insertion of the transmission device, the contact area of ​​the contacting element, which may be designed as a flat connector, for example, can have an insertion chamfer or corresponding insertion radii or the like. ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12

[0024] To adequately support the insertion forces that occur when electrically connecting the transmission device to the first contact area, it is particularly advantageous if the contacting element is reinforced, at least in the area of ​​the end facing the inductive transmission device. This ensures a reliable electrical connection even when blindly mating during subsequent installation of the transmission device on the contacting element.

[0025] The problem underlying the invention is also solved by a method for assembling a previously described rotor arrangement, in which the rotor windings are applied to the outer circumference of the rotor shaft by means of a laminated core arrangement and connected to the second contact area of ​​the contacting element, and in which the inductive transmission device is then axially inserted into the interior of the rotor shaft and electrically connected to the first contact area of ​​the contacting element by blind insertion or blind joining. This results in the advantages already described and further advantages.

[0026] The problem underlying the invention is also solved by a separately excited electric machine with the rotor arrangement described above. This results in the advantages already described and further advantages.

[0027] Furthermore, the problem underlying the invention is also solved by a vehicle with at least one externally excited electric motor. This results in the advantages already described and further advantages.

[0028] The present invention will be further explained with reference to the drawings.

[0029] They show:

[0030] Figure 1 shows a schematic three-dimensional view of a first embodiment of a rotor arrangement according to the invention; ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12

[0031] Figure 2 shows a schematic three-dimensional view of a second embodiment of the rotor arrangement according to the invention;

[0032] Figure 3 shows a schematic three-dimensional view of a contacting element as a stamped grid with plastic overmolding of the rotor arrangement according to Figure 1;

[0033] Figure 4 shows a partially cutaway view of the contact element as a stamped grid with plastic overmolding of the rotor arrangement according to Figure 1;

[0034] Figure 5 shows a schematic three-dimensional view of a contacting element as a stamped grid without plastic overmolding of the rotor arrangement according to Figure 2; and

[0035] Figure 6 shows a schematic three-dimensional view of the contacting element as a stamped grid with plastic overmolding of the rotor arrangement according to Figure 2.

[0036] Figures 1 to 6 illustrate various embodiments of a rotor arrangement with a hollow rotor shaft 1, using a separately excited electric machine 2 in a vehicle 3 as an example, from different perspectives. The separately excited electric machine 2 and the vehicle 3 are only schematically indicated in Figures 1 and 2.

[0037] Regardless of the specific design variant, an axially insertable inductive transmission device 4 with several electronic components, such as a transformer 15 with a secondary ferrite core and secondary coil, a rectifier board 16, and heat sinks 17, is provided inside the rotor shaft 1. Several rotor windings (not shown) are provided on the outer circumference of the rotor shaft 1 by means of a laminated core and are electrically connected to the transmission device 4. A contact point is provided for the electrical connection between the inductive transmission device 4 and the rotor windings. ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12

[0038] A contacting element 5, 5A, fixed in a radial shaft passage of the rotor shaft 1, is provided for contacting. The contacting element 5, 5A has a first axially aligned contact area 6 at one end facing the transmission device 4 for electrical connection to the transmission device 4 and a second contact area 7 at one end facing the rotor winding or the outer circumference of the rotor shaft for electrical connection to the rotor windings.

[0039] The contact element 5, 5A is designed as a metallic stamped grid with a plastic overmolding. The contact element 5, 5A is thus implemented as a component which, in addition to its function as a current conductor, also serves as an interface for connecting the rotor windings or rotor coils and as an interface for connecting the inductive transmission device in the form of an axially aligned plug-in connection for blind insertion, so that the transmission device can be inserted into the rotor shaft even after the rotor winding has been mounted. For this purpose, the contact in the area of ​​the first contact area 6 is designed, for example, as a plug connection, whereby the axial length 13 of the plug connection is dimensioned such that the axial tolerances and the required overlap with the connection socket on the transmission device 4 are ensured.

[0040] In the first embodiment of the rotor arrangement shown in Figures 1, 3, and 4, the stamped grid of the contacting element 5 has an L-shape, with the first contact area 6 being assigned to the shorter end of the L-shape and the second contact area 7 to the longer end. As can be seen particularly clearly in Figures 3 and 4, the shorter section of the L-shape with the first contact area 6 is axially aligned with the rotor shaft 1, while the second contact area 7 projects radially from the outer circumference of the rotor shaft 1 on the longer section of the L-shape. The plastic overmolding of the contacting element 5 has a flange collar 11, which enables centrifugal force support of the contacting element 5 on the rotor shaft 1 in the area of ​​the shaft passage. Furthermore, the end of the contacting element 5 facing the transmission device 4 is ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12

[0041] reinforced design to be able to absorb the axial insertion forces accordingly.

[0042] In the second embodiment of the rotor arrangement shown in Figures 2, 5, and 6, the stamped grid of the contacting element 5A has an L-shape only in sections. The first contact area 6 is assigned to the shorter end of the L-shape, while a first angled extension section 8 is attached to the longer end of the L-shape, followed by a further angled extension section 9. As is particularly evident from Figures 5 and 6, the shorter section of the L-shape is axially aligned with the first contact area 6 relative to the rotor shaft 1, while the second, also axially aligned, contact area 7 is located at the end of the further extension section 9. The extension sections 8 and 9 can bridge gaps between the contacting element 5A, which is attached to the transmission device 4, and the terminals of the rotor winding, if necessary.The first additional section 8 can be supported in an externally accessible axial groove of the rotor shaft 1. In the completed state of the rotor, particularly when the rotor lamination stack with the rotor windings has been slid onto the rotor shaft 1, the placement of the second contact area 8, e.g., below the lamination stack, simultaneously ensures good support of the contacting element 5A against centrifugal force. The additional sections 8 and 9 can, in principle, extend in both axial directions. The choice of orientation is determined by the position of the rotor coil contacting, the position of the transmission device 4, and the integration into the vehicle's drive system.

[0043] Regardless of the specific design variant, the first contact area 6, designed as a flat connector, has insertion chamfers 10 on both sides to facilitate blind insertion between the flat connector and the connection socket of the transmission device 4. The plastic overmolding of the stamped grid is shaped such that it provides reference surfaces 14 for, e.g., the angular alignment of the transmission device 4 to be mounted later, thus ensuring the correct positioning of the flat connector and socket when the transmission device 4 is inserted into the rotor shaft 1. The reference surfaces 14 can be located differently on the contacting element 5, 5A and on the shaft passage of the rotor shaft 1. ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12

[0044] The component is designed so that assembly is only possible in a precisely predetermined angular position. Furthermore, the plastic overmolding is shaped such that crimping or scraping ribs are arranged in the area of ​​the passage on the rotor shaft 1, ensuring that the contacting element 5, 5A is securely aligned and firmly seated within the rotor shaft 1 without play. If this is insufficient and, for example, high forces are expected to act on the component during rotor contacting, both components can be secured, clamped, and held in place by an additional mounting clip inserted into the rotor shaft 1.

[0045] The plastic overmolding of the contacting element 5, 5A is shaped in the area of ​​the shaft passage such that the clearance 12 is maintained. The creepage distance 12 can be adjusted, if necessary, by modifying the height of the circumferential flange collar. In the case of space constraints, the stamped grid can also be locally isolated in the critical area by painting and / or coating.

[0046] The prescribed rotor arrangement offers the further advantage that the transmission unit 4 can be disassembled / replaced, since the connection to the rotor can be relatively easily disconnected by loosening the plug connection, unlike soldered or welded connections. ZF Friedrichshafen AG File 304252

[0047] Friedrichshafen 2024-11-12

[0048] BezuQzeichen

[0049] 1 rotor shaft

[0050] 2 separately excited electric machine

[0051] 3 vehicles

[0052] 4 inductive transmission device

[0053] 5.5A contact element

[0054] 6 first contact area

[0055] 7 second contact area

[0056] 8 Additional Section

[0057] 9 further additional section

[0058] 10 Introduction phase

[0059] 11 Flange collars

[0060] 12 Air distance and creepage distances

[0061] 13 axial length or contact length

[0062] 14 reference areas

[0063] 15 Transformer with secondary ferrite core with secondary track 16 Rectifier board

[0064] 17 heat sinks

Claims

ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12 Patent claims 1. Rotor arrangement with a rotor shaft (1) designed as a hollow shaft for a separately excited electric machine (2), wherein an axially insertable inductive transmission device (4) and at least one rotor winding can be arranged inside the rotor shaft (1), and wherein a contact is provided for electrically connecting the inductive transmission device (4) and the rotor winding, characterized in that at least one contacting element (5, 5A) fixed in a radial shaft passage of the rotor shaft (1) is provided as contacting, wherein the contacting element (5, 5A) has a first axially oriented contact area (6) for electrical connection with the transmission device (8) at one end facing the transmission device (8) and a second contact area (7) for electrical connection with the rotor winding at one end facing the outer circumference of the rotor shaft (1).

2. Rotor arrangement according to claim 1, characterized in that the contacting element (5, 5A) is designed as a stamped grid having a plastic overmolding.

3. Rotor arrangement according to claim 2, characterized in that the stamped grid has an L-shape, wherein the first contact area (6) is assigned to one end of the shorter section of the L-shape and the second contact area (7) is assigned to one end of the longer section of the L-shape.

4. Rotor arrangement according to claim 2, characterized in that the stamped grid has an L-shape only in sections, wherein the first contact area (6) is assigned to one end of the shorter section of the L-shape, wherein at least one angled additional section (8) adjoins one end of the longer section of the L-shape, and wherein the axially aligned second contact area (7) is provided at one end of the last additional section (9). ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12 5. Rotor arrangement according to claim 4, characterized in that at least one of the additional sections (8, 9) is supported at least partially in an axially extending groove of the rotor shaft (1 ).

6. Rotor arrangement according to one of claims 2 to 5, characterized in that the outer shape of the plastic overmolding of the contacting element (5, 5A) forms a circumferential flange collar (11) for radially lateral force support in the area of ​​the shaft passage.

7. Rotor arrangement according to one of claims 2 to 6, characterized in that the plastic overmolding and the shaft passage have corresponding reference surfaces (14) for angular alignment of the contacting element (5, 5A) on the rotor shaft (1).

8. Rotor arrangement according to one of claims 2 to 7, characterized in that the dimensions of the plastic overmolding are selected such that the required air and creepage distances (12) are maintained.

9. Rotor arrangement according to one of the preceding claims, characterized in that the first axially aligned contact area (6) and / or the second contact area (7) is each designed as a detachable connector.

10. Rotor arrangement according to claim 9, characterized in that the connector is designed as a flat plug projecting axially from the contacting element (5, 5A) with at least one insertion phase for blind insertion.

11. Rotor arrangement according to claim 9 or 10, characterized in that the contacting element (5, 5A) is reinforced in the area of ​​the end (4) facing the inductive transmission device for plugging force support.

12. Method for mounting a rotor assembly according to one of the preceding claims, characterized in that rotor windings are applied to an outer circumference of a rotor shaft (1) by means of a lamination stack arrangement. ZF Friedrichshafen AG File 304252 Friedrichshafen 2024-11-12 and are connected to a second contact area of ​​a contacting element (5, 5A) of the rotor arrangement, and that subsequently an inductive transmission device (8) of the rotor arrangement is inserted axially into the rotor shaft (1) designed as a hollow shaft and is electrically connected by blind insertion to an axially aligned first contact area (6) of the contacting element (5, 5A).

13. Externally excited electrical machine (2) with a rotor arrangement according to one of claims 1 to 11.

14. Vehicle (3) with at least one externally excited electric machine (2) according to claim 13.

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