Rotor arrangement and method for manufacturing a rotor arrangement

Abstract

A rotor assembly for a current-excited synchronous machine and a method for manufacturing a rotor assembly are provided. The rotor assembly comprises a plurality of rotor windings arranged around a rotor core, wherein two adjacent rotor windings form a rotor gap. Furthermore, it comprises a first rotor gap closing element, wherein the first rotor gap closing element bridges the rotor gap between two adjacent rotor windings, and a second rotor gap closing element, wherein the second rotor gap closing element is formed in the rotor gap between two adjacent rotor windings. The rotor assembly is characterized in that the first rotor gap closing element and the second rotor gap closing element extend over the entire longitudinal extent of the rotor assembly.

Description

[0001] The present disclosure relates to a rotor assembly for a current-excited synchronous machine and / or a method for manufacturing the rotor assembly for a current-excited synchronous machine. Additionally or alternatively, a current-excited synchronous machine with a rotor assembly according to the disclosure and / or a motor vehicle with the current-excited synchronous machine according to the disclosure is provided.

[0002] Electric drive systems are increasingly being installed in modern motor vehicles, especially automobiles. These motors convert electrical energy into kinetic energy. Many synchronous motors currently used in electric cars operate with a permanent magnet in the rotor, the production of which requires rare earth elements. A current-excited synchronous motor can minimize the use of rare earth elements. Furthermore, controllability is improved because the rotor magnetic field is not permanent but depends on the applied voltage, and the torque drops less quickly and sharply at higher speeds. The rotor assembly (rotor) for current-excited synchronous motors is formed from a cast mold. Traditionally, a rotor gap closing element (cover slide or slot closure wedge) is located in the cast rotors, and this rotor gap closing element has a short, axially pronounced fin on one side of the rotor assembly.The presence of a fin and / or a contour is conventionally necessary in cast rotor arrangements for targeted control of crack initiation and crack propagation.

[0003] Longer paths and / or sections in the casting without targeted control of crack initiation and crack propagation by a rotor gap closure element or a fin can increase the risk of uncontrolled and unwanted crack initiation and crack propagation, which can cause damage to the winding (interturn short circuits). Known fin designs of the rotor assembly are disadvantageous and less efficient in this regard.

[0004] Against the background of this prior art, an object of the present disclosure can be seen in specifying a rotor arrangement and / or a method for producing the rotor arrangement which is suitable for enriching the prior art.

[0005] The problem is solved by the features of the independent claim. The subordinate claims and the dependent claims each contain optional developments of the disclosure.

[0006] According to this, the object is achieved by a rotor arrangement for a current-excited synchronous machine, wherein the rotor arrangement has a plurality of rotor windings arranged around a rotor core, and wherein two adjacent rotor windings form a rotor gap. Furthermore, the rotor arrangement has a first rotor gap closing element, wherein the first rotor gap closing element bridges the rotor gap between two adjacently arranged rotor windings, and a second rotor gap closing element is also provided, wherein the second rotor gap closing element is formed in the rotor gap between two adjacently arranged rotor windings. The first rotor gap closing element and the second rotor gap closing element are formed over the entire longitudinal extent of the rotor arrangement.

[0007] According to the disclosure, a first rotor gap closing element and a second rotor gap closing element can be provided between two adjacent rotor windings forming a rotor gap. Both rotor gap closing elements can have the same length.

[0008] The device described above offers a number of advantages. Among other things, the fact that the second rotor gap closure element, unlike the fin, extends over the entire axial length of the cast rotor allows for targeted crack initiation and propagation over the entire axial length of the cast rotor and simultaneously improves the process. Furthermore, the use of a second rotor gap closure element can save casting volume and facilitate both assembly and disassembly. This can lead to a reduction in both process costs (reduction in casting volume) and process times (shorter curing time for the smaller casting volume).Likewise, a simpler and faster disassembly of the rotor assembly and a pure separation of materials and recovery of raw materials in the sense of sustainable circular economy (Design for Circularity) can be made possible at the end of life (Eol - End of Lifetime).

[0009] Possible further developments of the device described above are explained in detail below.

[0010] The rotor assembly can be designed as a fully encapsulated housing. The windings of the rotor assembly can be encased in a potting compound. The term "fully encapsulated housing" can be understood to mean that the current-carrying components of the rotor and / or other components forming the rotor are completely encapsulated or encased in a potting compound, optionally an insulating material.

[0011] It can be provided that the second rotor gap closing element is positioned below or radially inside the first rotor gap closing element or radially further inside than the first rotor gap closing element. By introducing the second rotor gap closing element, which extends the same length as the first rotor gap closing element, the targeted crack initiation and crack propagation can be implemented over the entire axial length of the rotor arrangement. Furthermore, the distance between the second rotor gap closing element and the first rotor gap closing element can be kept to a minimum, which in turn serves to reduce crack formation. This results in only very short distances and minimal opportunities for uncontrolled crack initiation and crack propagation, whereby the crack initiation and crack propagation are largely predetermined and thus predictable over the entire axial length.

[0012] It can be provided that the first rotor gap closing element and the second rotor gap closing element have a tapered outer contour on both sides. This can achieve improved anchoring of the first rotor gap closing element and the second rotor gap closing element in the solid casting. The term "contour" can refer to an outer contour of the respective rotor gap closing element in cross-section in a plane to which a longitudinal axis of the rotor is perpendicular.

[0013] It can be provided that the first rotor gap closing element and the second rotor gap closing element (optionally in the cross-section, see above) are designed symmetrically (optionally axisymmetrically). The first rotor gap closing element can be designed in the form of a mandrel. The first rotor gap closing element and the second rotor gap closing element can thus be installed in any orientation with respect to an A-side or B-side installation position (where the A-side corresponds to a first axial end of the rotor and the B-side corresponds to the second axial end opposite the first axial end). This can reduce the effort and thus costs during assembly. The mandrel can be used to optimize the filling of the space between the adjacent rotor windings.

[0014] The second rotor gap closing element can be designed as a hollow profile. The hollow profile allows for weight reduction. The second rotor gap closing element can be designed as a thin-walled hollow profile provided as an extruded profile. The hollow profile allows for radial and axial positioning of the rotor gap closing element, particularly with respect to a support ring of the rotor.

[0015] It can be provided that the rotor arrangement has a support ring, and the support ring comprises retaining elements with a counter-contour for receiving and fixing the second rotor gap closing element. A counter-contour can be formed in the support ring as a retaining element, by means of which the second rotor gap closing element is held. The counter-contour can be formed as a protruding retaining element that can be received by the inner contour of the hollow profile. This allows for radial and axial fixation of the second rotor gap closing element in the rotor arrangement. The support ring can be attached to or on the rotor arrangement.

[0016] The above description can be summarized in other words and in a possible more concrete embodiment of the disclosure as described below, whereby the following description is not to be interpreted as limiting the disclosure.

[0017] It is conceivable that a fully cast SSM rotor is provided. A second rotor gap closure element (so-called cover slide) can be used as an inner cover slide on a smaller reference diameter, which can greatly reduce the challenges and resulting consequences of uncontrolled crack formation in the fully cast rotor.

[0018] Traditionally, the installed cover vane includes a so-called fin, which can be used for targeted crack initiation and propagation in the full encapsulation, thus preventing damage to the winding (interturn short circuits) due to uncontrolled crack formation. The fin of a conventional cover vane does not extend across the entire axial length of the rotor, but only over a short axial length on one axial end of the rotor.

[0019] In the disclosed concept, this fin can be omitted from the outer cover slide, and instead, a second, inner cover slide can be provided along the entire axial length. The second cover slide thus replaces the conventionally provided fin, so that, according to the disclosure, this fin in the form of this second cover slide can extend over the entire axial length of the rotor. Thus, targeted crack initiation and propagation can be achieved along the entire axial length of the rotor.

[0020] The inner cover slide can, optionally for weight reasons, be designed as a thin-walled hollow profile, e.g. as an extruded profile. The inner cover slide can be positioned radially and axially in the rotor via a contour and a corresponding counter-contour in another component of the rotor (in the disclosed concept the counter-contour can be located in the support rings). Because the original fin in the outer cover slide is omitted, both cover slides can have a symmetrical design and can therefore be installed in any orientation. No A- or B-side installation position needs to be taken into account for installation. This can save assembly costs for implementing poka-yoke. In the new concept, both cover slides can be located very close to one another, resulting in very short distances and minimal opportunities for uncontrolled crack initiation and crack propagation.This means that crack initiation and propagation can be largely predetermined and thus easily predictable over the entire axial length. The two cover slides of the new concept can be geometrically designed so that their outer contours are optimized for targeted crack initiation and propagation. In addition, their outer contours can have undercuts or a bilateral taper in the outer contour for secure anchoring in the full potting. The full potting can pose certain challenges to the assembly process and is difficult to separate from the other components during disassembly and can only be recycled mechanically or thermally. In the concept presented here, the use of a second cover slide can save potting volume and simplify both assembly and disassembly.This allows for a reduction in both process costs (reduction in potting volume) and process times (shorter curing time for the smaller potting volume). It also enables simpler and faster disassembly of the rotor assembly, as well as the separation of materials and the recovery of raw materials in line with a sustainable circular economy (Design for Circularity).

[0021] Furthermore, a current-excited synchronous machine with a stator arrangement and the rotor arrangement described above is provided. The above description with reference to the rotor arrangement also applies analogously to the current-excited synchronous machine, and vice versa.

[0022] Furthermore, a motor vehicle with the current-excited synchronous machine described above is provided. The motor vehicle can be a passenger car, in particular an automobile, or a commercial vehicle, such as a truck. The current-excited synchronous machine can serve as the primary and / or secondary drive for the motor vehicle. The above description with reference to the rotor arrangement and the synchronous machine also applies analogously to the motor vehicle, and vice versa.

[0023] Furthermore, a method for producing a rotor arrangement for a current-excited synchronous machine is provided. The rotor arrangement comprises a plurality of rotor windings arranged around a rotor core, wherein two adjacent rotor windings form a rotor gap, a first rotor gap closing element, wherein the first rotor gap closing element bridges the rotor gap between two adjacently arranged rotor windings, and a second rotor gap closing element, wherein the second rotor gap closing element is formed in the rotor gap between two adjacently arranged rotor windings. The first rotor gap closing element and the second rotor gap closing element are provided such that they are each formed over the entire longitudinal extent of the rotor arrangement.

[0024] What has been described above with reference to the rotor arrangement, the synchronous machine and the motor vehicle also applies analogously to the process and vice versa.

[0025] Below is an optional embodiment with reference to Fig. 1 to 6. Fig. 1 shows schematically a motor vehicle with a current-excited synchronous machine according to the disclosure, Fig. 2 shows schematically a rotor arrangement according to the disclosure in a perspective view, Fig. 3 shows schematically a cross-sectional view of a rotor arrangement according to the disclosure or a cross-section through a radially outer part of the rotor arrangement shown in Fig. 2 shown rotor arrangement according to the disclosure, Fig. 4 shows schematically the first and second rotor gap closing element from Fig. 3 in unique position, Fig. 5 shows schematically the second rotor gap closing element from Fig. 3 and Fig. 4 in unique position in a Fig. 2 corresponding perspective view, and Fig. 6 shows schematically a support ring of the rotor arrangement according to the disclosure Fig. 2 in unique position in a Fig. 2 and Fig. 5 corresponding perspective view.

[0026] The Fig. 1, the motor vehicle 1 shown only schematically has the disclosed synchronous machine 3 for driving the motor vehicle 1. In Fig. 1 only shows one synchronous machine 3, which does not preclude the possibility that one or more separate synchronous machines 3 may be provided to drive a front axle and / or a rear axle of the motor vehicle. Furthermore, a separate synchronous machine 3 may be provided to drive each wheel of the motor vehicle 1.

[0027] As from Fig. As can be seen in Figure 2, the synchronous machine 3 has the rotor assembly 2 according to the disclosure. The rotor assembly 2 is formed from a solid cast material. The synchronous machine 3 is designed as a current-excited synchronous machine. Alternatively, other technical implementations of the synchronous machine can be provided.

[0028] As from Fig. 3, the rotor assembly 2 has a plurality of rotor windings 4, 4', which are arranged around a rotor core. In the sectional view of the rotor assembly 2 of Fig. 3, only two rotor windings 4, 4' are shown for schematic clarity. The two adjacent rotor windings 4, 4' form a rotor gap 12. A first rotor gap closing element 5, 5' is introduced into the rotor gap 12, wherein the first rotor gap closing element 5, 5' bridges the rotor gap 12 between the two adjacently arranged rotor windings 4, 4'. In the context of the present disclosure, the reference symbol 5' stands for the further first rotor gap closing elements of the rotor arrangement 2, which are not shown in the figures. Furthermore, a second (inner) rotor gap closing element 6, 6' is provided, wherein the second rotor gap closing element 6, 6' is also formed in the rotor gap 12 between the two adjacently arranged rotor windings 4, 4'. In the context of the present disclosure, the reference symbol 6' stands for the further second rotor gap closing elements of the rotor arrangement 2, which are not shown in the figures.The second rotor gap closing element 6, 6' is positioned radially further inward than the first rotor gap closing element 5, 5'. A resulting distance 7 between the first rotor gap closing element 5, 5' and the rotor gap closing element 5, 5' is defined. Fig. 3 or 4 positioned under the first rotor gap closing element 5, 5', the second rotor gap closing element 6, 6' is designed to be as small as possible to reduce crack formation. This results in only very short paths and minimal opportunities for uncontrolled crack initiation and crack propagation. The first rotor gap closing element 5, 5' and the second rotor gap closing element 6, 6' are formed over the entire longitudinal extent of the rotor arrangement 2. The longitudinal extent corresponds to the entire longitudinal axis of the rotor arrangement 2, wherein the longitudinal axis in Fig. 3 and Fig. 4 runs perpendicular to the blade plane. This extension along the entire longitudinal axis allows for targeted crack initiation and propagation in the full encapsulation, thus preventing damage to the winding (interturn shortcuts) due to uncontrolled crack formation.

[0029] As from Fig. 4, the first rotor gap closing element 5, 5' and the second rotor gap closing element 6, 6' each have a double-sided taper in their outer contour 8. This outer contour 8 can be used to securely anchor the first rotor gap closing element 5, 5' and the second rotor gap closing element 6, 6' in the full casting. The outer contour 8 can be designed as an undercut or a double-sided taper. An undercut, or undercut, is a shape in which the inner side of the first rotor gap closing element 5, 5' and the second rotor gap closing element 6, 6' extends further inwards than the adjacent outer side. This creates the inward-facing cutout and / or the recess, which also enable secure anchoring.Furthermore, it can be provided that the first rotor gap closing element 5, 5' and the second rotor gap closing element 6, 6' are designed symmetrically, and the first rotor gap closing element 5, 5' is designed in the shape of a mandrel in order to optimally fill the rotor gap 12. Furthermore, the second rotor gap closing element 6, 6' can be designed as a thin-walled hollow profile, whereby the mass of the rotor assembly 2 can be reduced and thus optimized. The hollow profile can have an inner contour 9 for fastening.

[0030] In the Fig. 5 and Fig. 6 shows the second rotor gap closing element 6, 6' and the support ring 10 of the rotor assembly 2. As can be seen from Fig. 6, the support ring 10 has retaining elements 11. The retaining elements 11 have an outer contour which is designed to be inserted into the inner contour 9 of the second Fig.5. This plug-in connection allows for secure retention of the second rotor gap closing element 6, 6' and axial and radial positioning in the rotor assembly 2. The rotor assembly 2 can be manufactured using the method according to the disclosure. List of reference symbols 1 motor vehicle 2 Rotor arrangement 3 Synchronous machine 4, 4' rotor winding 5, 5' first rotor gap closing element 6, 6' second rotor gap closing element 7 Distance 8 Outer contour 9 Inner contour 10 support ring 11 holding elements 12 Rotor gap

Claims

[1] Rotor arrangement (2) for a current-excited synchronous machine (3), the rotor arrangement (2) comprising: - a plurality of rotor windings (4, 4') arranged around a rotor core, two adjacent rotor windings (4, 4') forming a rotor gap (12); - a first rotor gap closing element (5, 5'), wherein the first rotor gap closing element (5, 5') bridges the rotor gap (12) between two adjacently arranged rotor windings (4, 4'), and - a second rotor gap closing element (6, 6'), wherein the second rotor gap closing element (6, 6') is formed in the rotor gap (12) between two adjacently arranged rotor windings (4, 4'), characterized by , that - the first rotor gap closing element (5, 5') and the second rotor gap closing element (6, 6') are formed over the entire longitudinal extent of the rotor arrangement (2). [2] Rotor arrangement (2) according to claim 1, characterized bythat the rotor arrangement (2) is designed as a full cast housing. [3] Rotor arrangement (2) according to at least one of the preceding claims, characterized by that the second rotor gap closing element (6, 6') is positioned radially inside the first rotor gap closing element (5, 5'). [4] Rotor arrangement (2) according to at least one of the preceding claims, characterized by that the first rotor gap closing element (5, 5') and the second rotor gap closing element (6, 6') have a taper on both sides in their outer contour (8). [5] Rotor arrangement (2) according to at least one of the preceding claims, characterized by that the first rotor gap closing element (5, 5') and the second rotor gap closing element (6, 6') are designed symmetrically, and wherein the first rotor gap closing element (5, 5') is designed in the form of a mandrel. [6] Rotor arrangement (2) according to at least one of the preceding claims, characterized bythat the second rotor gap closing element (6, 6') is designed as a hollow profile, and the hollow profile has an inner contour (9) for fastening. [7] Rotor arrangement (2) according to at least one of the preceding claims, characterized by that the rotor arrangement (2) has a support ring (10) and the support ring (10) comprises holding elements (11) with a counter contour for receiving and fixing the second rotor gap closing element (6, 6'). [8] Current-excited synchronous machine (3) with a stator arrangement and a rotor arrangement (2) according to at least one of the preceding claims. [9] Motor vehicle (1), characterized by that the motor vehicle (1) comprises the current-excited synchronous machine (3) according to claim 8. [10] Method for producing a rotor arrangement (2) for a current-excited synchronous machine (3), comprising: a plurality of rotor windings (4, 4') arranged around a rotor core, wherein two adjacent rotor windings (4, 4') form a rotor gap; a first rotor gap closing element (5, 5'), wherein the first rotor gap closing element (5, 5') bridges the rotor gap (12) between two adjacently arranged rotor windings (4, 4'), and a second rotor gap closing element (6, 6'), wherein the second rotor gap closing element (6, 6') is formed in the rotor gap (12) between two adjacently arranged rotor windings (4, 4'), and wherein the method characterized by is that the first rotor gap closing element (5, 5') and the second rotor gap closing element (6, 6') are provided such that they extend over the entire longitudinal extent of the rotor arrangement (2).

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