Rotor having an end face cover

Abstract

The invention relates to a rotor for an electric machine, wherein the rotor comprises a rotor body, which has a first end face, and a first star disk, which lies against the first end face of the rotor body, wherein the first star disk has N threaded bores, where N≥2. The rotor also comprises electrically conductive windings, which form a first winding head on the first star disk, and a first end face cover for covering the first winding head, wherein the first end face cover has N bores for N screws for axially fixing the first end face cover to the first star disk. The first end face cover has a cover element which extends in the radial direction from a yoke region to an outer edge. The rotor also comprises an outer contact surface for the outer edge of the cover element of the first end face cover and N screw-connection contact surfaces for the N screws. The rotor is designed such that, when the first end face cover is in a stress-free state, a gap is present in the axial direction between the N screw-connection contact surfaces and the cover element of the first end face cover when the outer edge of the cover element of the first end face cover lies against the outer contact surface.

Description

[0001] 24-1452

[0002] Rotor with a front cover

[0003] The invention relates to an electric machine, such as a (current-excited) synchronous machine. In particular, the invention relates to a rotor of an electric machine having an end cap.

[0004] A vehicle powered at least partially by electricity comprises an electric machine for propelling the vehicle. The electric machine includes a stator that encloses a rotor of the electric machine, wherein a current-excited rotor has a rotor body with rotor heads in which electrically conductive windings are arranged to generate a magnetic field. The windings of the rotor form a winding head at each end face of the rotor, the windings being supported by a support disk arranged at each end face. An end cover can be attached to each support disk to cover the respective winding head. 24-1452

[0005] - 2 -

[0006] This document addresses the technical challenge of achieving a particularly reliable and robust fastening of a faceplate cover to an end face of a rotor.

[0007] The problem is solved by the independent claim. Advantageous embodiments are described, inter alia, in the dependent claims. It should be noted that additional features of a claim dependent on an independent claim, without the features of the independent claim itself or only in combination with a subset of the features of the independent claim, can constitute a separate invention independent of the combination of all features of the independent claim, which can be made the subject of an independent claim, a divisional application, or a subsequent application. This applies equally to technical teachings described in the description, which can constitute an invention independent of the features of the independent claims.

[0008] According to one aspect, a rotor for an electric machine, in particular for a (current-excited) synchronous machine, is described. The rotor comprises a rotor body, which typically has a plurality of rotor slots, each extending axially from a first end face to an opposite second end face of the rotor body. The rotor body may, for example, have 4 or more, or 6 or more rotor slots. The individual rotor slots may each be arranged between two salient poles of the rotor body. The individual salient poles may extend radially from the yoke of the rotor body away from the yoke. A central recess for the rotor shaft may be arranged in the yoke of the rotor body. The rotor shaft extends axially. 24-1452

[0009] - 3 -

[0010] The rotor comprises a first star disk abutting the first end face, wherein the first star disk has N threaded bores, with N > 2, in particular N > 3 or N > 6. The first star disk may have a yoke region abutting the yoke of the rotor body. Furthermore, the first star disk may have a leg region for each of the individual limb poles of the rotor body, the leg regions extending radially away from the yoke region of the star disk.

[0011] The rotor further comprises electrically conductive windings, typically arranged in the rotor slots, which form a first winding head on the first star disk. The rotor also includes a first end cover for covering the first winding head, the first end cover having N holes for N screws for axially fixing the first end cover to the first star disk.

[0012] The first stem disc can have a support element on each leg section (at the end furthest from the yoke area), which serves as a support for the first winding head (for centrifugal forces acting in a radial direction). The support elements of the leg sections can also serve as bearing surfaces for the first end cap, in particular for the edge element of the first end cap, on the first end face of the rotor body.

[0013] The rotor can have a first sleeve carrier arranged between the first end cover and the first stem plate, which has N sleeves for axially guiding the corresponding N screws from the corresponding N bores in the first cover to the corresponding N threaded bores in the first star plate. Each sleeve can have an axially extending bore through which a screw can be guided. The individual sleeves can each be tubular. 24-1452

[0014] - 4 -

[0015] The first sleeve carrier can be designed as a sealing element for sealing the rotor with potting compound, whereby the potting compound is introduced into the cavity between the first end cover and the first star disk (in order to support and / or fix the windings and / or the first winding head after the potting compound has hardened). This ensures efficient and reliable manufacturing of the rotor.

[0016] The N sleeves (of the first sleeve carrier) and the N threaded holes of the first star disk are preferably arranged rotationally symmetrically around the rotor shaft of the rotor. Alternatively or additionally, the N sleeves (of the first sleeve carrier) and the N threaded holes of the first star disk can each be arranged radially aligned with a corresponding rotomut of the plurality of rotomuts of the rotor body. Alternatively or additionally, the N sleeves (of the first sleeve carrier) and the N threaded holes of the first star disk can be arranged axially aligned with the yoke of the rotor body. In a preferred example, the number N of sleeves (of the first sleeve carrier) and / or the number N of threaded holes of the first star disk and the number of rotor slots of the rotor body are equal. Such a rotor design can provide a particularly stable rotor.

[0017] As previously explained, the first stem disk can have a plurality of leg sections extending radially away from the yoke area of ​​the first stem disk. The first end cover can be configured to cover the first winding head. In particular, the first end cover can have an edge element that circumferentially surrounds the first winding head and rests on the plurality of leg sections (especially on the support elements of the leg sections) of the first stem disk. This allows for the provision of a particularly robust rotor. 24-1452

[0018] - 5 -

[0019] The first end face cover comprises a cover element extending radially from the yoke area of ​​the cover element to its outer edge. The cover element may be oriented substantially perpendicular to the axial direction. The edge element of the first end face cover may extend radially from the cover element, particularly from its outer edge, towards the first end face.

[0020] The N bores in the cover element can be arranged in the yoke area of ​​the cover element of the first side cover. The yoke area of ​​the cover element can be aligned axially with the yoke of the rotor body.

[0021] The rotor includes an outer contact surface for the outer edge of the cover element of the first side cover. Furthermore, the rotor includes N screw contact surfaces for the N screws.

[0022] As previously explained, the rotor can have N sleeves for the corresponding N screws, with each individual sleeve extending axially from the cover element of the first end cap to the first star disk. The N sleeves can be arranged on the first sleeve carrier. The N contact surfaces for the N screws can be efficiently and reliably formed by the N sleeves, in particular by the end faces of the N sleeves.

[0023] The rotor is designed such that, in a stress-free state of the first end cover, a gap exists in the axial direction between the N screw contact surfaces and the cover element of the first end cover when the outer edge of the cover element of the first end cover (in particular, fully and / or completely) rests against the outer contact surface. 24-1452

[0024] - 6 -

[0025] The gap preferably has a gap width in the axial direction of

[0026] • 1% or more, in particular 2% or more, of the length of the individual screws; and / or

[0027] • 1% or more, in particular 2% or more, of the thickness of the cover element of the first stiction side cover; and / or

[0028] • 1% or more, in particular 2% or more, of the outer diameter of the cover element of the first Stimseitedeckel in the radial direction.

[0029] By providing a gap between the cover element, in particular between the back of the cover element, the first end cover and the N screw mounting surfaces, a particularly reliable axial fixation of the first end cover to the rotor can be achieved (even during operation of the electric machine).

[0030] The rotor is preferably designed such that the N screws can be screwed (or are screwed) so far into the corresponding N threaded bores of the star disk that

[0031] • the cover element, in particular the rear side of the cover element facing the first end face of the rotor body, of the first end face cover, rests against the N screw contact surfaces for the N screws; and

[0032] • Due to the (axial) tension of the cover element of the first timbral side cover, the outer edge of the cover element of the first timbral side cover is pressed axially against the outer contact surface with a specific stress (or pressure) value. The specific stress (or pressure) value is preferably 5 N / m². 2 or more.

[0033] This ensures a particularly reliable fixation of the first end cover to the rotor. 24-1452

[0034] - 7 -

[0035] As previously explained, the first end cap typically has a rim element at the outer edge of the cover element that circumferentially surrounds the first winding head and extends axially from the cover element towards the first end face of the rotor body. The rotor may also include a bandage enclosing the rim element. This bandage can provide particularly reliable fixation of the first end cap (in the radial direction).

[0036] The contact surface for the outer edge of the cover element of the first side cover can be efficiently formed by the bandage, in particular by an edge of the bandage (circumferentially).

[0037] The edge element of the first end face cover can be arranged, in particular clamped, between the support elements of the first star disc and the bandage. This ensures a particularly reliable fixation of the first end face cover.

[0038] The cover element of the first end cap can include one or more openings for introducing potting compound into the cavity formed between the first stem disc and the first end cap. This enables efficient manufacturing of the rotor.

[0039] The rotor body has a second end face arranged axially opposite the first end face. The rotor can be configured at the second end face analogously to the first end face. In particular, the rotor can include a second star disk abutting the second end face of the rotor body, the second star disk having N threaded holes. The electrically conductive windings can form a second winding head on the second star disk. The rotor can include a second end cover for covering the second winding head, the second star cover having N holes for N screws for axially fixing the second end cover to the second star disk. The second end cover can have a cover element extending radially from the yoke region of the cover element to the outer edge of the cover element.

[0040] The rotor can include an outer contact surface for the outer edge of the cover element of the second end cover. Furthermore, the rotor can include N screw contact surfaces for the N screws. Additionally, the rotor can be designed such that, in a stress-free state of the second end cover, a gap exists in the axial direction between the N screw contact surfaces and the cover element of the second end cover when the outer edge of the cover element of the second end cover rests against the outer contact surface.

[0041] According to another aspect, an electrical machine, in particular a (current-excited) synchronous machine, is described, which includes the rotor described in this document. Furthermore, the electrical machine typically includes a stator.

[0042] According to another aspect, a (road) motor vehicle (in particular a passenger car or a truck or a bus or a motorcycle) is described that includes the electric machine described in this document for propelling the vehicle.

[0043] It should be noted that the devices and systems described in this document can be used both alone and in combination with other devices and systems described in this document. Furthermore, any aspect of the devices and systems described in this document (24-1452)

[0044] - 9 - The devices and systems described can be combined with one another in a variety of ways. In particular, the features of the claims can be combined with one another in a variety of ways. Furthermore, features listed in parentheses are to be understood as optional features.

[0045] The invention will now be described in more detail using exemplary embodiments.

[0046] Figure a is an exemplary electrical machine;

[0047] Figure 1b shows a perspective view of an exemplary rotor body;

[0048] Figure 1c shows a perspective view of an exemplary slotted locking wedge;

[0049] Figure 2a shows a perspective view of an exemplary rotor with rotor windings;

[0050] Figure 2b shows an example of a front cover;

[0051] Figure 3a shows an end face of a rotor with an end face cover;

[0052] Figure 3b shows a sectional view through an end cap;

[0053] Figure 3c shows a gap at the front between a screw sleeve and the cover element of the side cover; and

[0054] Figure 3d shows a section of a bandage and a frontal cover.

[0055] As stated at the outset, this document deals with the efficient and reliable fastening of an end cap to an end face of the rotor of an electric machine. In this context, Fig. 1a shows an exemplary electric machine 100 in a view perpendicular to the shaft 101 of the electric machine 100. The shaft 101 of the electric machine 100 can correspond to the longitudinal axis of the stator 110 and / or the axis of rotation of the rotor 120 of the electric machine 100. Furthermore, the shaft 101 can run along the z-axis of the Cartesian coordinate system shown.

[0056] The electric machine 100 comprises a stator 110 with several

[0057] Stator windings 111, located at different angular positions around 24-1452

[0058] - 10 -

[0059] The rotor 120 is arranged around its axis of rotation and is configured to generate a rotating electromagnetic field. The stator 110 is surrounded by a housing 135 of the electric machine 100.

[0060] Furthermore, the electric machine 100 comprises the rotor 120, which is driven by the rotating magnetic field generated by the stator 110. The rotor 120 is rigidly connected to the shaft 101 driven by the electric machine 100 (which may be connected to the rotor shaft of the rotor 120 or may be identical to the rotor shaft of the rotor 120). The rotor 120 comprises a rotor body 122.

[0061] The rotor 120 of an electric machine 100 can have a laminated iron core (e.g., composed of mutually insulating sheets) as its rotor body 122. Fig. 1b shows an exemplary rotor body 122 of a rotor 120 in a perspective view. The rotor body 122 extends along the axis of rotation or the longitudinal axis of the rotor 120 (i.e., in the axial direction) from a first end face 128 to an opposite second end face 129. In the illustrated example, the rotor body 122 has different salient poles 124 arranged at different angular positions around the axis of rotation of the rotor 120. The salient poles 124 can be evenly distributed around the axis of rotation. Electrically conductive windings can be arranged around each salient pole 124, generating a magnetic field. The individual salient poles 124 can thus form magnetic poles of the rotor 120.

[0062] The rotor body 122 has a central opening 123, in particular a bore, into which the rotor shaft of the rotor 120 can be inserted. The rotor shaft can be rotatably mounted on the end faces of the rotor body 122 via respective bearing surfaces to allow rotation of the rotor 120. 24-1452

[0063] - 11 -

[0064] Between each pair of directly adjacent salient poles 124 of the rotor body 122, a rotomut 125 is formed, in which the windings of the adjacent salient poles 124 are arranged. A rotomut 125 extends along the longitudinal and / or rotational axis from the first end face 128 to the opposite second end face 129 of the rotor body 122.

[0065] The rotomut 125 between two directly adjacent (circumferentially) salient poles 124 has an opening 126 on the outer surface of the rotor body 122 facing away from the rotor shaft, the opening 126 extending along the longitudinal axis from the first end face 128 to the second end face 129 of the rotor body 122. In the direction perpendicular to the longitudinal axis, the opening 126 is bounded by (mutually facing) legs 131 of the pole shoes 130 of the two directly adjacent salient poles 124.

[0066] To manufacture a rotor 120, electrically conductive windings can be wound around the salient poles 124, such that windings of the two directly adjacent salient poles 124 are arranged in each rotor slot 125. After arranging the windings, the openings 126 of the individual rotor slots 125 can each be covered with a slot closure wedge 180 (see Fig. 1c). A slot closure wedge 180 can be inserted from an end face 128 between the legs 131 of the pole shoes 130 of the two directly adjacent salient poles 124 to cover the opening 126.

[0067] Fig. 2a shows a perspective view of a rotor 120 with a rotor body 122, wherein a rotor shaft 202 is arranged in the central opening 123 of the rotor body 122. Furthermore, rotor windings 201 are arranged around each of the individual salient poles 124. The rotor windings 201 form a winding head 206 on each of the two end faces 128, 129 of the rotor body 122. The openings 126 of the individual rotor slots 125, which are to be covered, can be seen between the pole shoes 130 of the individual salient poles 124. 24-1452

[0068] - 12 -

[0069] During operation of the electric machine 100, centrifugal forces in a radial direction act on the rotor 120, in particular on the winding heads 206 at the two end faces 128, 129 of the rotor body 122. These forces could damage the electric machine 100, especially the windings 201. To absorb the forces acting on the winding heads 206, a cup-shaped end cap 210 can be arranged on each end face of the rotor 120 (see Fig. 2b). The end cap 210 has a cover element 212 extending substantially parallel to the respective end face, which covers the respective end face in the axial direction. The cover element 212 has a central, circular recess 216 through which the shaft 202 of the rotor 120 passes.

[0070] The end cap 210 further comprises an annular edge element 213 that extends axially from the outer edge of the cover element 212 (in particular from the outer edge of the cover element 212) towards the rotor body 122. The edge element 213 has an inner surface 214 which, in the installed state of the end cap 210, can, for example, rest on bearing areas (in particular on support elements) of the star disk 250 of the rotor 120 (in order to fix the end cap 210 to the rotor body 122). The star disk 250 can bear against the end face 128, 129 of the rotor body 122. The individual bearing areas can be formed by the lateral surface of the star disk 250 (in particular by support elements of the star disk 250).

[0071] During assembly, a faceplate cover 210 can be slid axially onto the support areas of the respective stem disk 250 on both end faces of the rotor 120, so that the winding heads 206 on both end faces of the rotor 120 are covered by a faceplate cover 210 (both axially and radially). 24-1452

[0072] - 13 -

[0073] The fixation of an end cover 210 can be achieved by an interference fit between the end cover 210 and the star disk 250, in particular between the edge element 213 of the end cover 210 and the cylindrical surface (especially the support elements) of the star disk 250. To also ensure axial fixation, the end cover 210 can be screwed to the support disk 250. For this purpose, the end cover 210, in particular the cover element 212 of the end cover 210, can have one or more bores 217 through which a screw can be passed to fix the end cover 210 to the star disk 250.

[0074] The star disk 250 itself can be fixed to the rotor body 112 via the respective winding head 206 and / or via an interference fit between the star disk 250 and the rotor shaft 202.

[0075] As shown by way of example in Fig. 3a, the rotor 120 can, in addition to the end cap 210 with the cover element 212 and the edge element 213, have a bandage 313 to fix the end cap 210 to an end face 128, 129 of the rotor body 122, in particular to a stem disk 250. The bandage 313 can be arranged around the edge element 213 of the end cap 210.

[0076] As shown in Fig. 3a, screws 301 can be arranged in the individual bores 217 of the cover element 212 of the end cover 210, with which the end cover 210 is attached in an axial direction to the end face 128, 129 of the rotor body 122, in particular to a star disk 250, in particular screwed on.

[0077] Fig. 3b shows a sectional view of the components arranged on an end face 128, 129 of the rotor body 122. In particular, Fig. 3b shows the thrust washer 250 abutting the end face 128, 129, which has N threaded bores 302 for corresponding N screws 301, e.g. with N>2, in particular N>3 or - 14 -

[0078] N>6. The individual screws 301 can each be arranged in a sleeve 321, the individual sleeves 321 each extending axially from the cover element 212 of the end cover 210 to the star washer 250, in particular to a threaded bore 302 of the star washer 250. The N sleeves 321 for the corresponding N screws 301 can be arranged on a sleeve carrier 320, so that the N sleeves 321 can be efficiently provided by a single component.

[0079] The star disk 250 can have a yoke area in which the N threaded bores 302 are arranged. The yoke area can abut the yoke of the rotor body 122. Furthermore, the star disk 250 can have leg areas for the corresponding salient poles 124 of the rotor body 122. Each leg area can extend radially away from the yoke area. The individual leg areas of the star disk 250 can each abut the corresponding salient pole 124 of the rotor body 122.

[0080] At the ends of the leg sections of the stem disk 250 facing away from the yoke area, a support element 304 can be arranged, which is designed to support the winding head 206 arranged on the respective end face 128, 129 in a radial direction (when centrifugal forces act on the winding head 206). The individual support elements 304 can each extend axially away from the respective end face 128, 129. The individual support elements 304 (on the outer side facing away from the rotor shaft 202) can each be designed as a bearing surface for the end cover 210, in particular for the edge element 213 of the end cover 210.

[0081] Fig. 3b shows how the edge element 213 of the end cap 210 rests on the outside of the support element 304 of a leg area of ​​the thrust washer 250. Furthermore, Fig. 3b shows how the bandage 313 - 15 -

[0082] The edge element 213 of the end cover 210 surrounds the edge element 213 of the end cover 210, so that the edge element 213 of the end cover 210 is arranged, in particular clamped, between the bandage 313 and the outside of the support elements 304 of the leg areas of the star disk 250.

[0083] During operation of the electric machine 100, despite the screw fastening via the N screws 301, the edge element 213 of the end cover 210 can be driven axially away from the respective end face 128, 129 and out of the space between the support elements 304 of the thrust washer 250 and the bandage 313. The cover element 212 of the end cover 210 can then warp away from the respective end face 128, 129 at its (circular) outer edge. Such deformation of the rotor 120 can impair the operation of the electric machine 100. In particular, the deformation can cause an imbalance.

[0084] The rotor 120 can have a screw contact surface 315 for each of the N screws 301 on the rear side of the cover element 212 of the end cover 210 facing the end face 128, 129 of the rotor body 122 (see Figures 3b to 3e). The individual screws 301 can be screwed into the corresponding threaded bores 302 of the stem plate 250 to such a depth that the rear side of the cover element 212 of the end cover 210 rests on the screw contact surfaces 315 for the individual screws 301. The screw contact surfaces 315 can be formed by the end faces of the sleeves 321 for the individual screws 301 and / or by the sleeve carrier 320.

[0085] The rotor 120 is preferably designed such that when the cover element 212 of the end cover 210 (without tension) rests in the axial direction against the bandage 313 and / or against the support elements 304 of the star disk 250, between the back of the cover element 212 of the end cover 210 and 24-1452

[0086] - 16 - a gap 305 is formed in the axial direction between the N screw contact surfaces 315. The gap 305 can have a gap width in the axial direction of

[0087] • 1% or more, in particular 2% or more, of the length of the individual screws 301; and / or

[0088] • 1% or more, in particular 2% or more, of the thickness of the cover element 212 of the end cover 210; and / or

[0089] • 1% or more, in particular 2% or more, of the diameter of the cover element 212 of the end cover 210 (in the radial direction).

[0090] During the manufacture of the rotor 120, the N screws 301 can be screwed into the corresponding N threaded bores 302 to such a great extent and / or tightly that the rear side of the cover element 212 of the end cover 210 rests on the screw contact surfaces 315 for the N screws 301. As a result, a preload is generated, which presses the outer edge of the cover element 212 of the end cover 210 axially against the bandage 313 and / or against the support elements 304 of the star disk 250. This preload efficiently and reliably prevents the outer edge of the cover element 212 of the end cover 210 from moving axially away from the respective end face 128, 129 of the rotor body 122 during operation of the electric machine 100, and thereby impairing the operation of the electric machine 100 (especially by means of an imbalance).

[0091] This allows the two end caps 210 to be screwed to the thrust washers 250 with screws 301, which bear against the end faces 128, 129 of the rotor body 122. This enables a backlash-free and easy-to-manufacture fastening of the end caps 210.

[0092] Especially when the end caps 210 are designed as heat sinks, the highest possible contact pressure of the end caps 210 against the respective 24-1452 is required.

[0093] - 17 -

[0094] Bandage 313 is advantageous. This can be achieved by pre-tensioning the individual end caps 210. When an end cap 210 is placed (without tension) against the corresponding bandage 313, a gap 305 can be maintained in the area of ​​the screw connection (i.e., in the yoke area) to the screw contact surface 315 of the screw connection. The screw connection axially tensions the end cap 210, resulting in a higher contact pressure of the end cap 210 (in the axial direction) against the bandage 313. The end cap 210 can be screwed to the star washer 250 with N screws 301, which are arranged in corresponding N spacers 321. The gap 305 for the pre-tensioning can be formed between the end cap 210 and the N spacers 321. The present invention is not limited to the embodiments shown.It should be noted in particular that the description and the figures are only intended to illustrate the principle of the proposed devices and systems by way of example.

Claims

Claims 1) Rotor (120) for an electric machine (100), wherein the rotor (120) comprises, - a rotor body (122) with a first end face (128); - a first star disk (250) abutting the first end face (128) of the rotor body (122), wherein the first star disk (250) has N threaded bores (303), with N>2; - electrically conductive windings (201) which form a first winding head (206) on the first star disk (250); - a first end cover (210) for covering the first winding head (206), wherein the first end cover (210) has N bores (217) for N screws (301) for axially fixing the first end cover (210) to the first star disk (250); wherein the first end cover (210) has a cover element (212) extending radially from a yoke area to an outer edge; - an outer contact surface for the outer edge of the cover element (212) of the first side cover s (210); and - N screw contact surfaces (315) for the N screws (301); wherein the rotor (120) is designed such that in a stress-free state of the first end cover (210) there is a gap (305) in the axial direction between the N screw contact surfaces (315) and the cover element (212) of the first end cover (210) when the outer edge of the cover element (212) of the first end cover (210) rests against the outer contact surface. 2) Rotor (120) according to claim 1, wherein the rotor (120) is designed such that the N screws (301) are screwed into the corresponding N threaded bores (302) of the star disk (250) to such an extent that 24-1452 - 19 - - the cover element (212), in particular the rear side of the cover element (212) facing the first end face (128, 129) of the rotor body (122), of the first end face cover (210) rests against the N screw contact surfaces (215) for the N screws (301); and - due to tension of the cover element (212) of the first end cover (210), the outer edge of the cover element (212) of the first end cover (210) is pressed in an axial direction with a certain stress value against the outer contact surface. 3) Rotor (120) according to claim 2, wherein the determined voltage value is 5 N / m 2 or more. 4) Rotor (120) according to one of the preceding claims, wherein the gap (305) has a gap width in the axial direction of - 1% or more, in particular 2% or more, of the length of the individual screws (301); and / or - 1% or more, in particular 2% or more, of the thickness of the cover element (212) of the first end cover (210); and / or - 1% or more, in particular 2% or more, of an outer diameter of the cover element (212) of the first Stimseitedeckel (210) in the radial direction. 5) Rotor (120) according to one of the preceding claims, wherein - the N bores (217) are arranged in the yoke area of ​​the cover element (212) of the first end cover (210); and - the yoke area of ​​the cover element (212) is aligned in the axial direction with the yoke of the rotor body (122). 24-1452 - 20 - 6) Rotor (120) according to one of the preceding claims, wherein - the first end face cover (210) has an edge element (213) on the outer edge of the cover element (212) that surrounds the first winding head (206) in the circumferential direction and extends in the axial direction away from the cover element (212) to the first end face (128, 129) of the rotor body (122); - the rotor (120) comprises a bandage (313) enclosing the edge element (213); and - the contact surface for the outer edge of the cover element (212) of the first end cover (210) is formed by the bandage (313), in particular by an edge of the bandage (313). 7) Rotor (120) according to claim 6, wherein - the first stem disk (250) has a plurality of leg regions that extend radially away from a yoke region of the first star disk (250); - each leg section has a support element (304) at one end facing away from the yoke section for supporting the first winding head (206) in a radial direction; and - the edge element (213) of the first end face cover (210) is arranged, in particular clamped, between the support elements (304) of the first support disc (250) and the bandage (313). 8) Rotor (120) according to one of the preceding claims, wherein - the rotor (120) has N sleeves (321) for the corresponding N screws (301); - the individual sleeves (321) each extend in an axial direction from the cover element (212) of the first end cover (210) to the first stem plate (250); and - the N contact surfaces (315) for the N screws (301) by the N sleeves (321), in particular by end faces of the N sleeves (321), 24-1452 - 21 - are formed. 9) Rotor (120) according to claim 8, wherein the N sleeves are arranged on a first sleeve carrier (320). 10) Rotor (120) according to one of the preceding claims, wherein the cover element (212) of the first end cover (210) comprises one or more openings (215) for introducing potting compound into a cavity formed between the first star disk (250) and the first end cover (210). 11) Rotor (120) according to one of the preceding claims, wherein - the rotor body (122) has a second end face (129) which is arranged in the axial direction opposite the first end face (128); - the rotor (120) comprises a second stem disk (250) abutting the second end face (129) of the rotor body (122), wherein the second stem disk (250) has N threaded bores (303), with N>2; - the electrically conductive windings (201) on the second stem disk (250) form a second winding head (206); - the rotor (120) comprises a second end cover (210) for covering the second winding head (206), wherein the second end cover (210) has bores (217) for screws (301) for axially fixing the second end cover (210) to the second stem disk (250); wherein the second end cover (210) has a cover element (212) extending radially from a yoke area to an outer edge; - the rotor (120) comprises an outer contact surface for the outer edge of the cover element (212) of the second end cover (210); and 24-1452 - 22 - - the rotor (120) comprises N screw contact surfaces (315) for the N screws (301); wherein the rotor (120) is designed such that in a stress-free state of the second end cover (210) there is a gap (305) in the axial direction between the N screw contact surfaces (315) and the cover element (212) of the second end cover (210) when the outer edge of the cover element (212) of the second end cover (210) rests against the outer contact surface.

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