ROTOR FOR A ROTATING ELECTRIC MACHINE, ELECTRIC MACHINE

Description

[0001] The invention relates to a rotor for a rotating electric machine of a motor vehicle or an electrically powered aircraft, which is at least partially electrically powered. The rotor has a plurality of pole teeth on which a rotor winding capable of being energized by an external current is arranged, the rotor winding being secured and / or fixed in position on the pole teeth by a keyway. The invention also relates to an electric machine with the rotor according to the invention.

[0002] Electric motors are increasingly being installed in modern vehicles. They are used particularly as fully integrated drive motors within the powertrain or in hybrid applications, for example as starter generators or axle motors. These applications sometimes utilize separately excited synchronous machines, which have a rotor consisting of a laminated core equipped with an excitation winding and / or a rotor winding. In such rotors, slots are formed between the wound pole teeth.

[0003] During operation, both internal and external rotor motors experience high centrifugal forces that can pull the excitation winding out of the slots. These centrifugal forces depend on the rotational speed and the weight of the slot components. Therefore, especially in high-speed machines, the winding is additionally secured after assembly. Various binding agents are known for this purpose, used as impregnating resins or potting compounds.

[0004] Additionally, slot stops or wedges can be used to prevent the winding from being pulled out of the slot. A slot stop is known, for example, from German patent application DE 28 17 951 A1. For rotors designed for high-speed electric motors (10,000 revolutions per minute and more), it would be advantageous to secure the internal slot components, especially the excitation winding, even more effectively against centrifugal forces occurring during operation.

[0005] EP 1 494 335 A1 describes a rotor arrangement with a multi-part slotted wedge, the clamping elements of which are held in position by a ring applied at the end.

[0006] US 2020 177 046 A1 describes a one-piece formed slot wedge.

[0007] The object of the invention is to provide a rotor for a rotating electrical machine whose rotor winding is arranged securely on the pole teeth even at high rotational speeds.

[0008] This problem is solved by the subject matter of the independent claim. Preferred embodiments of the invention are specified in the dependent claims and the following description, each feature being able to represent an aspect of the invention both individually and in combination. According to the invention, a rotor for an electric machine of an at least partially electrically powered motor vehicle is provided, comprising a rotor disk rotatable about a rotor axis with at least two pole teeth directed radially outwards in the direction of the rotor disk and spaced apart from each other in the circumferential direction of the rotor disk, each pole tooth having a pole neck and a pole shoe adjoining the pole neck, and a currentable rotor winding arranged on each pole neck, wherein a groove is formed between the rotor winding of the two pole teeth spaced apart from each other.a multi-part, self-locking slot wedge engaging in the slot and supporting against the pole shoe, wherein, as a result of rotation of the rotor about its rotor axis under centrifugal force, the slot wedge exerts a contact force in the tangential direction on the respective rotor winding bearing against the slot wedge and secures and / or fixes it in its position on the pole neck.

[0009] In other words, one aspect of the present invention is the provision of a rotor for an electric machine. The electric machine is preferably used in the drive train of a motor vehicle that is at least partially electrically powered. However, it is also conceivable that the electric machine could be used in the propulsion system of an electrically powered aircraft, for example, a drone.

[0010] The rotor has a rotor axis around which it is rotatably arranged and / or mounted. Furthermore, the rotor has a rotor disk, which can also be referred to as a laminated core. The rotor disk is preferably formed from a plurality of laminated sheets arranged one behind the other.

[0011] However, it is also conceivable that the rotor disk and / or the lamination stack are formed from a single piece. The rotor disk is preferably annular and has at least two pole teeth spaced apart from each other in the circumferential direction of the rotor on its radially outward-facing outer surface. Typically, the rotor has more than two pole teeth, which are spaced apart from each other at regular intervals in the circumferential direction of the rotor on the outer surface of the annular rotor disk.

[0012] Each pole tooth has a pole neck adjacent to the outer surface and a pole shoe adjacent to the pole neck. The pole neck can also be called the pole shaft. In other words, the pole neck is formed between the outer surface of the annular rotor disk and the pole shoe. The pole tooth is typically hammer-shaped. In other words, the cross-section of the pole shoe adjacent to the pole neck is larger than the cross-section of the pole neck. A current-carrying rotor winding is arranged on the pole neck. A rotor winding is also known as an excitation winding.

[0013] A groove is formed between the rotor windings of the two spaced-apart pole teeth. The groove can have a V-shaped configuration and preferably extends between the pole teeth to the outer surface of the annular rotor disk. A multi-part, self-locking wedge is arranged in the groove. As the rotor rotates around its axis under centrifugal force, the wedge exerts a clamping force on the respective rotor winding bearing against it, fixing and / or positioning it on the pole neck. Self-locking means that the wedge clamps itself into the groove under centrifugal force as the rotor rotates around its axis, or that the clamping force of the wedge in the groove is increased, thus ensuring that the wedge is securely positioned in the groove.Since the contact force of the slot wedge on the rotor winding is exerted during a rotation of the rotor around its rotor axis, and this force is increased at high speeds, a secure positioning of the rotor winding on the pole teeth can be achieved even at high rotor speeds, preferably greater than 10,000 rpm.

[0014] An advantageous embodiment of the invention lies in the fact that the pole shoe has a bearing surface on one side facing the rotor axis, and the slot wedge is supported at least partially against this bearing surface. The bearing surface faces the rotor axis and / or the outer surface of the rotor disk and extends from a distal end formed in the tangential direction of the pole shoe to the rotor winding arranged on the pole neck. By supporting the slot wedge against the bearing surface, the slot wedge can be securely fixed in the groove in the radial direction.

[0015] In a preferred embodiment of the invention, the slot wedge comprises a V-shaped first wedge with a tip and two webs, and a second wedge with a wedge tip arranged at least partially between the two webs, wherein the tip of the V-shaped first wedge is directed inwards in the radial direction of the rotor disk, and the wedge tip of the second wedge points outwards in the radial direction of the rotor disk, and the second wedge is arranged to be displaceable at least partially in the radial direction of the rotor disk, the two webs of the V-shaped first wedge bear against the rotor winding with their outer sides, and a distal end of the webs of the first wedge is supported against the bearing surface in a radial direction outwards, wherein the second wedge is guided between the inner sides of the webs.and under the influence of centrifugal force, the second wedge undergoes a displacement in the radial direction of the rotor disk outwards, thereby acting against the inner sides of the webs of the first wedge and exerting a contact force on the rotor winding via the outer sides of the webs of the V-shaped first wedge.

[0016] The first wedge is V-shaped and has two webs that intersect at a single point, or converge at that point. The point where the two webs converge forms the apex of the V-shaped first wedge, which points inwards in the radial direction of the rotor disk. Each web has a distal end facing away from the apex. The distal end of the webs rests, at least partially, against the bearing surface of the pole shoe. In this way, the first wedge is securely positioned in the groove with respect to the radial direction of the rotor disk. Each web has an outer surface that faces the rotor winding located on the pole tooth and rests against it. Furthermore, each web has an inner surface. The inner surfaces of the webs face each other. The second wedge is arranged between the inner surfaces of the two webs so that it can be moved radially along the rotor disk.The tip of the second wedge points radially outwards. The first and second wedges are operatively connected, so that when the rotor rotates around its axis, the second wedge is displaced radially along the rotor disk. The second wedge acts against the inner side of the webs, slightly spreading the V-shaped first wedge, and the outer side of the webs exerts a clamping force on the rotor winding to secure it in position on the pole neck.

[0017] According to the invention, the contact force acts on the rotor winding in a tangential direction of the rotor winding, with reference to a symmetry axis of a pole tooth formed in the radial direction of the rotor disk.

[0018] In this context, an advantageous further development of the invention lies in the fact that, with respect to the cross-section of the slot wedge, the web has a section whose wall thickness increases along the longitudinal direction of the web towards the distal end, and an outer surface of the second wedge, under the influence of centrifugal force, bears against and acts upon this section, at least partially. In other words, a gap in the first wedge between the inner surfaces of the webs can have a shape that tapers radially towards the rotor disk. In this way, a contact surface is formed on the inner surface of the webs against which the second wedge acts when the rotor rotates about its axis, in order to exert a contact force on the rotor winding via the webs.

[0019] Furthermore, it is advantageously provided that a cross-sectional expansion is formed adjacent to the radially outward-projecting wedge tip of the second wedge, which rests at least partially on the distal ends of the webs. The cross-sectional expansion thus does not engage in the gap between the inner surfaces of the webs, but rather rests at least partially on the distal ends of the webs. The cross-sectional expansion allows the second wedge to be given a certain direction and / or position within the gap, so that it acts precisely on the corresponding contact points on the inner surface of the webs when the rotor rotates.

[0020] It is further advantageous that the distance between the ribs in the region of the distal ends is smaller than the maximum width of a region of the second wedge located within the gap. This prevents the second wedge from sliding out of the gap of the first wedge under the influence of centrifugal force.

[0021] A further advantageous embodiment of the invention lies in the fact that the width of the cross-sectional expansion of the second wedge, which does not project into the interior of the first wedge, is greater than the distance between the webs in the region of the distal ends. This ensures that the cross-sectional expansion of the second wedge does not enter the gap, but rather aligns the area of ​​the second wedge within the gap accordingly.

[0022] In principle, the first wedge and the second wedge can be made of different materials. It is also conceivable that the first wedge and the second wedge can be made of the same material. Preferably, the first wedge and the second wedge are made of a plastic and / or at least partially or partially comprise a plastic. The plastic allows, for example, the first wedge to deform, in particular to spread, so that it can exert a contact force on the rotor winding. The plastic is preferably a thermosetting plastic. Thermosetting plastics have increased temperature resistance. This can be advantageous for use in stators, as these can reach high temperatures during operation. As an alternative to the design of a slotted wedge with a first wedge and a second wedge, an advantageous further development of the invention consists in...that the slotted wedge comprises a first pressure element, a second pressure element, and a wedge element, wherein the first pressure element and the second pressure element are designed to be displaceable in the tangential direction of the rotor disk, and the wedge element is arranged to be displaceable in the radial direction, the wedge element being in operative contact with the first pressure element and the second pressure element, such that by a rotation of the rotor about the rotor axis, the wedge element is displaced outwards in the radial direction of the rotor disk and acts against the first pressure element and the second pressure element, thereby moving them away from each other in the tangential direction of the rotor disk and exerting a pressure force on the rotor winding in order to position and / or fix it securely on the respective pole tooth.

[0023] In other words, the alternative embodiment provides that the slot wedge is formed in at least three parts and comprises a first pressure element, a second pressure element, and a wedge element. The first and second pressure elements are arranged in the groove so as to be displaceable relative to each other in the tangential direction of the rotor disk, with each of the two pressure elements having an outer surface facing away from each other and towards the respective rotor winding. The wedge element is arranged between an outer surface of the rotor disk and the two pressure elements, with a wedge tip of the wedge element pointing outwards in the radial direction of the rotor disk and acting between the first and second pressure elements when the rotor rotates about its rotor axis.This causes the two wedge elements to be displaced in a tangential direction to the rotor disk and exerts a pressing force on the rotor winding via the outside to secure it in its position on the pole tooth.

[0024] In this context, an advantageous further development of the invention lies in the fact that the first pressure element and the second pressure element interlock at least partially. In other words, the first pressure element and the second pressure element can, for example, be connected to each other via a tongue-and-groove connection, which allows the two pressure elements to be displaced in the tangential direction of the rotor disk.

[0025] It is further advantageous that the first and second pressure elements form a wedge recess on one side facing the rotor axis, and that the wedge element has a wedge tip that is directed outwards in the radial direction of the rotor disk and engages at least partially in the wedge recess. The wedge recess thus forms a kind of guide for the wedge element, so that when displaced radially along the rotor disk, it acts effectively and precisely against the two pressure elements to displace them tangentially along the rotor disk, thereby exerting a corresponding pressure force on the rotor winding via the pressure elements and their respective outer surfaces.

[0026] In a preferred embodiment of the invention, the first pressure element and / or the second pressure element are supported at least partially on the bearing surface of the pole tooth. In this way, the pressure elements can be arranged in a positionally secure manner with respect to their position in the radial direction of the rotor disk within the groove.

[0027] In principle, the rotor can be designed to have only one rotor disk. An advantageous embodiment of the invention lies in the fact that the rotor has a plurality of rotor disks arranged one behind the other in the axial direction of the rotor without any inclination.

[0028] The invention also relates to an electric machine with the rotor according to the invention. The electric machine is preferably a drive unit or a generator. It is particularly advantageous for the electric machine to be arranged in a drive train of a motor vehicle that is at least partially electrically powered. However, it is also conceivable that the electric machine could be used in a drive unit of an electrically powered aircraft, for example, a drone.

[0029] Further features and advantages of the present invention will become apparent from the dependent claims and the following exemplary embodiments.

[0030] The exemplary embodiments are not limiting but rather intended to be illustrative. They are meant to enable a person skilled in the art to carry out the invention. The applicant reserves the right to make one or more of the features disclosed in the exemplary embodiments the subject of patent claims or to include such features in existing patent claims. The exemplary embodiments are explained in more detail with reference to the drawings.

[0031] In show these: Fig. 1 a three-dimensional view of a rotor according to an embodiment of the invention; Fig. 2 a cross-section through the rotor according to a preferred embodiment of the invention; Fig. 3 a detailed view of a slot wedge in a first preferred embodiment of the invention; Fig. 4 a detailed view of a slot wedge in a second preferred embodiment of the invention.

[0032] In Fig. 1 A three-dimensional view of a rotor 10 for an electric machine is shown. The electric machine is preferably used in a drive train of a motor vehicle that is at least partially electrically powered. Fig. 2 A cross-section through rotor 10 is shown.

[0033] The following refers to the Fig. 1 und 2 Reference is made simultaneously to the following: The rotor 10 has a rotor shaft 14 that can be rotated about a rotor axis 12. At least one rotor disk 16 is arranged on the rotor shaft 14 in a rotationally fixed manner. Rotationally fixed means that, during rotation of the rotor 10 about the rotor axis 12, the rotor disk 16 does not undergo any relative rotation in the circumferential direction of the rotor 10 with respect to the rotor shaft 14.

[0034] The rotor disk 16 can also be referred to as a laminated core. The rotor disk 16 typically comprises a plurality of laminated sheets arranged one behind the other. The rotor disk 16 is annular in shape and has at least two pole teeth 20 spaced apart from each other on its radially outward-facing outer surface 18, arranged circumferentially around the rotor 10. As a rule, the rotor 10, as also in Fig. 1 shown, more than two pole teeth 20 are formed on the outer side 18 of the annular rotor disk 16, spaced at regular intervals from each other in the circumferential direction of the rotor 10.

[0035] Preferably, the rotor disk 16 and the pole teeth 20 are formed in one piece. This means that a sheet metal part has a ring-shaped configuration and the pole teeth 20 are arranged on it. For example, such a sheet metal part with the pole teeth 20 is produced by a stamping process.

[0036] Each pole tooth 20 has a pole neck 22 adjacent to the outer surface 18 and a pole shoe 24 adjacent to the pole neck 22. In other words, the pole neck 22 is formed between the outer surface 18 of the annular rotor disk 16 and the pole shoe 24. The pole tooth 20 is hammer-shaped. Thus, the cross-section of the pole shoe 24 adjacent to the pole neck 22 is larger than the cross-section of the pole neck 22. A current-carrying rotor winding 26 is arranged and / or wound on the pole neck 22.

[0037] A groove 28 is formed between the rotor winding 26 of the two spaced-apart pole teeth 30. The groove 28 has a V-shaped configuration and extends between the pole teeth 20 to the outer surface 18 of the annular rotor disk 16. A multi-part, self-locking wedge 30 is arranged at least partially in the groove 28, wherein, as a result of rotation of the rotor 10 about its rotor axis 12 under the influence of centrifugal force 31, the wedge 30 exerts a contact force 48 on the respective rotor winding 26 bearing against the wedge 30 and fixes it in its position on the pole neck 22. Since the contact force 48 of the slot wedge 30 is exerted on the rotor winding 26 during a rotation of the rotor 10 about its rotor axis 12, and this force is increased at high speeds, a secure positioning of the rotor winding 26 on the pole teeth 20 can be made possible even at high speeds of the rotor 10, preferably greater than 10,000 rpm.

[0038] In Fig. 3 Figure 1 shows a detailed view of the rotor disk 16 in the area of ​​the groove 28 or the groove wedge 30. The groove wedge 30 is shown in a first preferred embodiment. Accordingly, the groove wedge 30 has a first V-shaped wedge 32. The first wedge 32 is formed by two webs 34 that intersect at a point, or converge at that point. The point at which the two webs 34 converge forms the tip 36 of the V-shaped first wedge 32. The tip 36 is directed inwards in the radial direction of the rotor disk 16. The webs 34 each have a distal end 38 that faces away from the tip 36. The distal end 38 of the webs 34 rests, at least partially, against a bearing surface 40 of the pole shoe 24.The bearing surface 40 is formed on one side of the pole shoe 24 facing the rotor axis 12 and extends from a distal end of the pole shoe 24, relative to a tangential direction of the rotor disk 16, to the rotor winding 26 arranged on the pole neck 22. In this way, the first wedge 32 is securely seated in the groove 28. Each web 34 has an outer surface 42 that faces the rotor winding 26 arranged on the pole tooth 20 and bears against the rotor winding 26. Furthermore, each web 34 has an inner surface 44. The inner surfaces 44 of the webs 34 face each other. The second wedge 46 is arranged to be displaceable in the radial direction of the rotor disk 16 between the inner surfaces 44 of the two webs 34. The wedge tip 49 of the second wedge 46 is directed radially outwards.The first wedge 32 and the second wedge 46 are operatively connected to each other, such that when the rotor 10 rotates about its rotor axis 12, the second wedge 46 is displaced radially along the rotor disk 16. The second wedge 46 acts, at least partially, against the inner surface 44 of the webs 34, spreading the webs 34 so that the outer surface 42 of the webs 34 exerts a contact force 48 on the rotor winding 26, fixing it in position on the pole neck 22.

[0039] With respect to the cross-section of the slot wedge 30, the webs 34 each have a section 50 whose wall thickness increases along the longitudinal direction of the web 34 towards the distal end 38, and an outer wedge surface 52 of the second wedge 46, under the influence of centrifugal force 31, bears against and acts upon the section 50, at least partially. In other words, a gap 54 of the first wedge 32 between the inner surfaces 44 of the webs 34 can have a tapered shape, relative to a radial direction of the rotor disk 16, which is directed outwards. In this way, a contact surface is formed on the inner surface 44 of the webs 34 against which the second wedge 46 acts when the rotor 10 rotates about its rotor axis 12, in order to exert the contact force 48 on the rotor winding 26 via the webs 34.

[0040] The radially outward-facing wedge tip 49 of the second wedge 46 has a cross-sectional expansion 56, which rests at least partially on the distal ends 38 of the webs 34. The cross-sectional expansion 56 thus does not engage in the space 54 between the inner surfaces 44 of the webs 34, but rather rests at least partially on the distal ends 38 of the webs 34. The cross-sectional expansion 56 allows the second wedge 46 to be guided in a certain direction and / or position within the space 54, so that when the rotor 10 rotates, it acts precisely on the corresponding contact points on the inner surface 44 of the webs 34.

[0041] In Fig. 4A detailed view of the rotor disk 16 in the area of ​​the groove 28 or the groove wedge 30 is shown. The groove wedge 30 is shown in a second preferred embodiment. The groove wedge 30 has a first pressure element 58, a second pressure element 60, and a wedge element 62. The first pressure element 58 and the second pressure element 60 are designed to be displaceable in the tangential direction of the rotor disk 16.The wedge element 62 is arranged to be displaceable in the radial direction of the rotor disk 16, wherein the wedge element 62 is in operative connection with the first pressure element 58 and the second pressure element 60, so that by a rotation of the rotor 10 about the rotor axis 12 the wedge element 62 is displaced outwards in the radial direction of the rotor disk 16 and acts against the first pressure element 58 and the second pressure element 60, whereby these are moved away from each other in the tangential direction of the rotor disk 16 and exert a pressure force 48 on the rotor winding 26 in order to secure it in its position on the pole tooth.

[0042] The first pressure element 58 and the second pressure element 60 interlock at least partially. For example, the first pressure element 58 and the second pressure element 60 are connected to each other via a tongue-and-groove connection 64, which allows the two pressure elements 58, 60 to be displaced in the tangential direction of the rotor disk 16.

[0043] Furthermore, it is provided that the first pressure element 58 and the second pressure element 60 form a wedge recess 66 on one side facing the rotor axis 12, and that the wedge element 62 has a wedge tip 68 which is directed outwards in the radial direction of the rotor disk 16 and engages at least partially in the wedge recess 66. The wedge recess 66 thus forms a kind of guide for the wedge element 62, so that when it is displaced in the radial direction of the rotor disk 16, it acts effectively and precisely against the two pressure elements 58, 60 in order to displace them in the tangential direction of the rotor disk 16 or to exert a corresponding pressure force 48 on the rotor winding 26 via the pressure elements 58, 60.

Claims

1. Rotor (10) for an electric machine of an at least partially electrically driven motor vehicle, having a rotor disc (16) which can be rotated about a rotor axis (12) and has at least two pole teeth (20) which are directed outwards in the radial direction of the rotor disc (16) and spaced apart from each other in the circumferential direction of the rotor disc (16), wherein each pole tooth (20) has a pole neck (22) and a pole shoe (24) adjoining the pole neck (22), an energizable rotor winding (26) arranged on each pole neck (22), wherein a groove (28) is formed between the rotor winding (26) of the two pole teeth (20) arranged spaced apart from each other, a multipart and self-locking groove wedge (30) engaging in the groove (28) and supported against the pole shoe (24), wherein the groove wedge (30), as a result of rotation of the rotor (10) about its rotor axis (12) under the influence of centrifugal force (31), exerts a contact-pressure force (48) in the tangential direction onto the respective rotor winding (26) bearing against the groove wedge (30) and secures and / or fixes the rotor winding in its position on the pole neck (22).

2. Rotor according to Claim 1, characterized in that the pole shoe (24) has a bearing surface (40) on a side facing the rotor axis (12), and the groove wedge (30) is supported against this bearing surface (40) at least in sections.

3. Rotor according to Claim 1 or 2, characterized in that the groove wedge (30) has a V-shaped first wedge (32) having a tip (36) and two webs (34) and a second wedge (46) arranged at least partially between the two webs (34) and having a wedge tip (49), wherein the tip (36) of the V-shaped first wedge (32) is directed inwards in the radial direction of the rotor disc (16), and the wedge tip (49) of the second wedge (46) faces outward in the radial direction of the rotor disc (16), and the second wedge (46) is arranged at least partially displaceably in the radial direction of the rotor disc (16), the two webs (34) of the V-shaped first wedge (32) bear against the rotor winding (26) by way of their outer side (42), and a distal end (38) of the webs (34) of the first wedge (32) is supported against the bearing surface (40) outwards in the radial direction, wherein the second wedge (46) is guided between the inner sides (44) of the webs (34), and under the influence of centrifugal force (31) the second wedge (46) is displaced outwards in the radial direction of the rotor disc (16) and in so doing acts against the inner sides (44) of the webs of the first wedge (32) and exerts a contact-pressure force (48) onto the rotor winding (26) via the outer sides (42) of the webs (34) of the V-shaped first wedge (32).

4. Rotor according to Claim 3, characterized in that, based on the cross section of the groove wedge (30), the web (34) has a section (50), the wall thickness of which is designed to increase over the longitudinal direction of the web (34) in the direction of the distal end (38), and a wedge outer surface (52) of the second wedge (46) bears against the section (50) under the influence of centrifugal force (31) at least in sections and acts against the section.

5. Rotor according to either of Claims 3 or 4, characterized in that a cross-sectional widened portion (56), which sits on the distal ends (38) of the webs (34) at least in sections, is formed adjoining the wedge tip (49) of the second wedge (46) formed outwards in the radial direction.

6. Rotor according to Claim 1 or 2, characterized in that the groove wedge (30) has a first contact-pressure element (58), a second contact-pressure element (60) and a wedge element (62), wherein the first contact-pressure element (58) and the second contact-pressure element (60) are arranged displaceably in the tangential direction of the rotor disc (16), and the wedge element (62) is arranged displaceably in the radial direction, the wedge element (62) is operatively connected to the first contact-pressure element (58) and the second contact-pressure element (60), so that, owing to rotation of the rotor (10) about the rotor axis (12), the wedge element (62) is displaced outwards in the radial direction of the rotor disc (16) and acts against the first contact-pressure element (58) and the second contact-pressure element (60), as a result of which the first and the second contact-pressure element are moved away from each other in the tangential direction of the rotor disc (16) and exert a contact-pressure force (48) onto the rotor winding (26) in order to secure the rotor winding on the respective pole tooth (20) in its position.

7. Rotor according to Claim 6, characterized in that the first contact-pressure element (58) and the second contact-pressure element (60) interengage at least in sections.

8. Rotor according to Claim 6 or 7, characterized in that the first contact-pressure element (58) and the second contact-pressure element (60) form a wedge receptacle (66) on a side facing the rotor axis (12), and the wedge element (62) has a wedge tip (68) which is directed outwards in the radial direction of the rotor disc (16), and engages into the wedge receptacle (66) at least in sections.

9. Rotor according to any of Claims 6 to 8, characterized in that the first contact-pressure element (58) and / or the second contact-pressure element (60) are / is supported on the bearing surface (40) of the pole shoe (24) at least in sections.

10. Rotor according to any of the preceding claims, characterized in that the rotor (10) has a plurality of rotor discs (16), which are arranged in succession in the axial direction of the rotor (10) without skewing.

11. Electric machine with a rotor (10) according to one of the preceding claims.