Rotor for an electric machine of a motor vehicle, and motor vehicle

Abstract

The invention relates to a rotor (1) for an electric machine of a motor vehicle, having at least one excitation winding, having at least one slip ring (5), and having at least one conductor (7) electrically connected to the slip ring (5) and to a contact element (9) which is formed separately from the conductor (7) and which is electrically connected to the excitation winding and via which the conductor (7) is electrically connected to the excitation winding, wherein the contact element (9) itself has no surface extending in a plane running perpendicular to the axial direction (12) of the rotor (1) and has no surface tangent to a plane running perpendicular to the axial direction (12) of the rotor (1).

Description

[0001] Rotor for an electric machine of a motor vehicle and motor vehicle

[0002] The invention relates to a rotor for an electric machine of a motor vehicle, in particular a motor vehicle, according to the preamble of patent claim 1. Furthermore, the invention relates to a motor vehicle, in particular a motor vehicle, with at least one such rotor.

[0003] DE 102005 031 535 B4 discloses a slip ring assembly for a rotor of an electrical machine, comprising at least one first slip ring. At least one first connecting conductor is held in sections within an insulating material of the slip ring assembly, which is electrically conductively connected to the at least one first slip ring. Also provided is an end of the connecting conductor facing away from the first slip ring, the end of which is provided for electrical connection to a field winding. Furthermore, JP 5705238 B2 discloses an electrical machine comprising a housing and a rotor.

[0004] The object of the present invention is to provide a rotor for an electric machine and a motor vehicle with at least one such rotor, so that a particularly advantageous production of the electric machine can be realized.

[0005] This object is achieved according to the invention by a rotor having the features of patent claim 1 and by a motor vehicle having the features of patent claim 10. Advantageous embodiments of the invention are the subject of the dependent claims.

[0006] A first aspect of the invention relates to a rotor for an electric machine of a motor vehicle, also simply referred to as a vehicle. This means that the motor vehicle, preferably designed as a motor vehicle, in particular as a passenger car, in its fully manufactured state has the electric machine and thus the rotor and can be driven by means of the electric machine, in particular purely electrically. In its fully manufactured state, the electric machine has the rotor and a stator, by means of which the rotor can be driven and can therefore be rotated about a machine axis of rotation relative to the stator. In particular, the electric machine can provide drive torques for driving the motor vehicle via its rotor.Very preferably, the electrical machine is a high-voltage component whose electrical voltage, in particular electrical operating or nominal voltage, is preferably greater than 50 volts, in particular greater than 60 volts, and very preferably amounts to several hundred volts. The rotor has at least one excitation winding, which is also simply referred to as a winding or rotor winding. For example, the rotor has a laminated core through which the excitation winding is carried. Furthermore, it is provided, for example, that the rotor has a rotor shaft. In particular, the laminated core is formed separately from the rotor shaft and is connected to the rotor shaft in a rotationally fixed manner, wherein, for example, the laminated core is arranged on the rotor shaft. In particular, the electrical machine can provide the drive torques via the rotor shaft.

[0007] The rotor also has at least one slip ring. Preferably, the slip ring is formed separately from the rotor shaft and arranged on the rotor shaft. In particular, the slip ring is provided in addition to the laminated core and is preferably formed separately from the laminated core. For example, the slip ring can be part of a slip ring assembly, which is also referred to as a slip ring module (SRM). The rotor also has at least one conductor, which is formed, for example, from an electrically conductive, metallic material such as copper. For example, the conductor is formed as a wire, which is also referred to as a conductor wire or connecting wire. The conductor is electrically, i.e. electrically conductively, connected to the slip ring, such that an electrical current can be transmitted from the conductor to the slip ring and / or vice versa.For example, the conductor is formed separately from the slip ring and electrically connected to the slip ring. Also provided is a contact element formed separately from the conductor and, for example, separately from the slip ring and preferably also separately from the excitation winding, which is electrically connected to the excitation winding so that an electrical current can be transmitted from the excitation winding to the contact element and / or vice versa. Thus, the conductor is electrically connected to the excitation winding via the contact element. Overall, it can be seen that the slip ring, the conductor, the contact element, and the excitation winding are electrically connected to one another so that an electrical current can be transmitted between them.In particular, for example, an electrical current can be transmitted from the stator to the slip ring and from the slip ring via the conductor and the contact element to or onto the excitation winding, in order to supply the excitation winding with the electrical current. Conversely, it is conceivable that an electrical current can be transmitted from the excitation winding via the contact element and the conductor to or onto the slip ring and from the slip ring to the stator, as a result of which the electrical current can be discharged from the excitation winding. In particular, in the fully manufactured state of the electrical machine, for example, the slip ring, which is rotatable about the machine axis of rotation relative to the stator, is in direct contact with at least one corresponding component of the stator, as a result of which a sliding contact, also referred to as a sliding contact, and thus an electrical connection, is formed between the component and the slip ring.Thus, the aforementioned electrical current can be transmitted, for example, from the component to the slip ring and / or vice versa via the sliding contact. The component is, for example, a brush, particularly designed as a carbon brush. When the rotor and thus the slip ring rotate about the machine's rotational axis relative to the stator and thus relative to the component, the slip ring slides, particularly directly, against the component. During this sliding movement, electrical current is or can be transmitted between the component and the slip ring via the sliding contact.

[0008] In order to be able to realize a particularly advantageous, in particular a particularly time- and cost-effective, manufacture of the rotor and thus of the electrical machine as a whole, it is provided according to the invention that the contact element per se, that is, considered on its own, is free of a surface extending in a plane perpendicular to the axial direction of the rotor and free of a surface tangent to a plane perpendicular to the axial direction of the rotor. In other words, the contact element neither has a surface extending in a plane perpendicular to the axial direction of the rotor, nor does the contact element have a surface tangent to a plane perpendicular to the axial direction of the rotor. The axial direction of the rotor, whose radial direction is perpendicular to the axial direction of the rotor, coincides with the machine's axis of rotation. When reference is made above and below to the axial direction,Unless otherwise stated, this refers to the axial direction of the rotor, and when reference is made below and above to the radial direction, this refers, unless otherwise stated, to the radial direction of the rotor. Since the contact element has neither a surface extending in a plane perpendicular to the axial direction of the rotor nor a surface tangent to a plane perpendicular to the axial direction of the rotor, the contact element per se, i.e. considered on its own, is free of a surface in the axial direction of the rotor delimiting a contacting area in which the conductor, particularly during manufacture and thus during assembly of the rotor and thus of the electrical machine, can be brought into direct contact with a contact surface of the contact element and thus electrically connected to the contact element, whereby,In particular during the manufacture or assembly of the rotor and thus of the electrical machine, several different contacting positions of the conductor are permitted, i.e. possible, in the axial direction of the rotor, which, in particular during the manufacture or assembly of the rotor and thus of the electrical machine, can be moved into the contacting positions relative to the contact element and, in the contacting positions, can be brought into direct contact with the contact surface and can thus be electrically connected to the contact element. Thus, the conductor can be moved into the contacting positions, in particular during the assembly or manufacture of the rotor and thus of the electrical machine, wherein the conductor, when it is in a respective one of the contacting positions,is in direct contact with the contact surface and is thereby electrically contacted with the contact element. In particular, it is provided, for example, that when the conductor is in, in particular exactly, one of the contacting positions, the conductor is locked relative to the contact element, so that relative movements between the conductor and the contact element are prevented. For example, the conductor is locked relative to the contact element in such a way that the conductor is integrally connected to the contact element, in particular soldered to the contact element. Thus, for example, in the rotor according to the invention, it is provided that the conductor is locked relative to the contact element, in particular by the conductor being integrally connected to the contact element, in particular soldered to the contact element. The invention thus allows a simple,axial tolerance compensation of the conductor to the contact element, also simply referred to as a contact, which is, for example, a contact element of a rotor star disk. Such a star disk is disclosed, for example, in DE 102018 128 521 A1.

[0009] In the following and previously, the term “axial” means the axial direction of the rotor, and the term “radial” means the radial direction of the rotor.

[0010] The invention is based in particular on the following findings and considerations: In principle, it would be conceivable for the contact element to be fork-shaped and, for example, designed as a so-called crimping fork, in which case, however, the contact element itself would have a surface that delimits the contacting area in the axial direction and extends in a plane running perpendicular to the axial direction of the rotor or is tangent to a plane running perpendicular to the axial direction of the rotor. In order to advantageously connect the conductor electrically and mechanically to the crimping fork, so that relative movements between the conductor and the crimping fork are prevented, the conductor must be pushed to a base of the crimping fork, so that the conductor directly touches the base of the crimping fork. As a result, a crimping process in which the crimping fork is crimped in order to thereby lock the conductor relative to the crimping fork,as desired. The base of the crimp fork forms the previously mentioned surface that limits the contact area in the axial direction. However, if an axial tolerance occurs between the base of the crimp fork and the conductor, whereby such axial tolerances are technically determined and thus unavoidable, these axial tolerances should be compensated for. For this purpose, for example, the crimp fork, also referred to as the contact bridge, is connected to a separate switching ring. During the manufacture of the rotor, the switching ring is axially displaced, in particular together with the conductor, in order to compensate for axial tolerances, so that the conductor then rests against a base, also referred to as the crimp fork base. However, a winding wire that was previously electrically contacted with the switching ring, for example by crimping, and from which at least a portion of the excitation winding is formed,be further deformed and, for example, bent. This can cause additional residual stresses in the winding wire, and in particular in a crimping area in which the winding wire is crimped to the switching ring, whereby these residual stresses increase the risk of subsequent wire breaks and / or wire tears in the winding wire during operation of the electrical machine. The aforementioned problems and disadvantages can now be avoided by the invention. In the invention, the contact element acting or designed as an electrical contact for the conductor is designed with regard to its geometry, in particular on the outer circumference, such that during the manufacture of the rotor and, for example, during a connection process by which or during which the conductor is connected to the contact element electrically and, for example, also mechanically, for example by soldering and / or crimping,so that, as a result, relative movements between the conductor and the contact element are prevented, an axial displacement, i.e. an axial positioning of the conductor relative to the contact element, in particular over several millimeters, is permitted, i.e., enabled. This means, as previously described, that the conductor can fundamentally be electrically contacted, i.e., electrically connected, to the contact element in each of the contacting positions mentioned, which are successive in the axial direction and thus different from one another. This means that the conductor can be positioned in the axial direction relative to the contact element as required and can be locked, i.e., fixed, in, in particular, precisely one of the contacting positions relative to the contact element and electrically connected to the contact element. As a result, in the connection process, also referred to as the contacting process,in which or by which the conductor is electrically and preferably also mechanically connected to the contact element, an axial tolerance compensation is carried out in order to be able to compensate for axial tolerances between the conductor and the contact element as required. The contact element, which is referred to as a contact bridge or designed as a contact bridge, can be firmly integrated, for example, into the insulation of a star disk of the rotor, such a star disk being disclosed, for example, in DE 102018 128 521 A1. Thus, for example, in comparison to conventional solutions, at least one additional component can be omitted, whereby the number of parts, the costs, the weight and the installation space requirement of the rotor can be kept particularly low. Likewise, for example, contacting of a connecting wire of the excitation winding is carried out at fixed connection points in particular. The invention can prevent excessive,additional deformation of the winding wire can be avoided, so that the risk of damage or destruction, such as wire tears or wire breaks of the field winding wire, can be kept particularly low. In other words, the fact that the contact element is free of a surface that delimits the contacting area in the axial direction and extends in a plane perpendicular to the axial direction of the rotor or is tangent to a plane perpendicular to the axial direction of the rotor allows for a very extensive mobility, i.e., over a very large distance in the axial direction, and thus positioning of the conductor relative to the contact element, so that a multitude of successive contacting positions in the axial direction,into which the conductor could be moved relative to the contact element in the axial direction and in which the conductor could be brought into direct contact with the contact element and thereby electrically connected to the contact element, so that axial tolerances between the conductor and the contact element can be easily and as needed compensated without excessive deformation of the conductor or the winding wire occurring. The conductor can thus be selectively brought into one of the contacting positions and, in this one contacting position, electrically and preferably also mechanically connected to the contact element, so that a particularly advantageous axial tolerance compensation can be achieved. In order to be able to manufacture the rotor and thus the electrical machine particularly simply and thus in a time- and cost-effective manner, one embodiment of the invention providesthat the conductor is in direct contact with the contact surface of the contact element, whereby the conductor is electrically connected to the contact element.

[0011] In order to achieve a particularly simple and, in particular, time- and cost-effective production of the rotor and thus of the electrical machine, it has proven particularly advantageous if the contact surface extends, in particular exclusively, in a plane which runs parallel to the axial direction of the rotor.

[0012] This allows for particularly extensive and needs-based axial tolerance compensation to be created.

[0013] A further embodiment is characterized in that the contact surface extends in the axial direction of the rotor over more than two millimeters, in particular over more than three millimeters, and most preferably over more than four millimeters. This allows for a particularly extensive positioning of the conductor relative to the contact element, i.e., over a particularly large distance, so that particularly good axial tolerance compensation can be achieved. This allows the electrical machine to be manufactured particularly quickly and cost-effectively.

[0014] In a further, particularly advantageous embodiment of the invention, it is provided that the conductor has a first longitudinal region and a second longitudinal region which runs obliquely or perpendicular to the first longitudinal region and in particular directly adjoins the first longitudinal region and ends at a free end of the conductor. In particular, for example, the second longitudinal region runs parallel to the axial direction of the rotor, wherein alternatively or additionally, for example, the first longitudinal region runs in the radial direction of the rotor. The longitudinal regions can create a particularly advantageous and simple axial tolerance compensation between the conductor and the contact element, so that the rotor and thus the electrical machine can be manufactured particularly quickly and cost-effectively.

[0015] In order to be able to manufacture the rotor and thus the electrical machine in a particularly time- and cost-effective manner, a further embodiment of the invention provides that the second length region is electrically connected to the contact element, such that the conductor is electrically connected to the contact element via the second length region. In order to compensate for axial tolerances in a particularly advantageous manner and thus to be able to manufacture the rotor in a particularly time- and cost-effective manner, a further embodiment of the invention provides that the second length region of the conductor is in direct contact with the contact surface of the contact element, in particular with regard to the first length region and the second length region exclusively, as a result of which the second length region and thus the conductor is electrically connected to the contact element.

[0016] In a further, particularly advantageous embodiment of the invention, the contact element has a C-shaped or U-shaped receptacle which is open in a first direction running in the radial direction of the rotor and pointing away from the rotor shaft, is delimited on both sides, in particular directly, by the contact element in the circumferential direction of the rotor running around the axial direction and thus around the machine rotation axis, and is delimited, in particular directly, by the contact element in a second direction running in the radial direction of the rotor and opposite the first direction and pointing towards the rotor shaft, in which receptacle the second longitudinal region is arranged. On the one hand, this enables a particularly advantageous and easy-to-implement axial tolerance compensation between the conductor and the contact element to be achieved.On the other hand, this ensures precise positioning of the conductor relative to the contact element, so that the rotor and thus the electrical machine can be manufactured particularly easily and thus particularly time- and cost-effectively.

[0017] Finally, it has proven particularly advantageous for the realisation of a particularly simple and thus time- and cost-effective production of the rotor and thus of the electrical machine if the conductor has a circular cross-section.

[0018] A second aspect of the invention relates to a motor vehicle, also simply referred to as a vehicle, which is preferably designed as a motor vehicle, in particular as a passenger car. The motor vehicle has at least one electric machine, by means of which the motor vehicle can be driven, in particular purely electrically. The electric machine has a stator and a rotor according to the first aspect of the invention. The rotor can be driven by the stator and is rotatable about a machine rotation axis relative to the stator. Advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention, and vice versa. Further details of the invention emerge from the following description of preferred embodiments with the associated drawings.

[0019] Fig. 1 shows a schematic and partially sectioned

[0020] Perspective view of a rotor for an electric machine of a motor vehicle;

[0021] Fig. 2 is a schematic perspective view of a slip ring module of the

[0022] Rotors;

[0023] Fig. 3 shows a partial schematic perspective view of a first

[0024] Design of the rotor; and

[0025] Fig. 4 shows a partial schematic perspective view of a second

[0026] Design of the rotor.

[0027] In the figures, identical or functionally identical elements are provided with the same reference numerals.

[0028] Fig. 1 shows a detail in a schematic and partially sectioned perspective view of a rotor 1 for an electric machine of a motor vehicle, also simply referred to as a vehicle. This means that the motor vehicle, which is preferably designed as a motor vehicle, in particular as a passenger car, in its fully manufactured state has the electric machine and can be driven by means of the electric machine, in particular purely electrically. In its fully manufactured state, the electric machine has the rotor 1 and a stator, by means of which the rotor 1 can be driven and can therefore be rotated about a machine axis of rotation relative to the stator. The electric machine can provide drive torques for driving the motor vehicle via the rotor 1.

[0029] The rotor 1 has a rotor shaft 2 and a laminated core 3 which is formed separately from the rotor shaft 2 and connected to the rotor shaft 2 in a rotationally fixed manner and is arranged in particular along a length of the rotor shaft 2 and thus on the rotor shaft 2. Furthermore, the rotor 1 has at least one excitation winding (not shown in the figures), which is also referred to as a winding or rotor winding. The excitation winding is carried by the laminated core 3. In conjunction with Fig. 2, it can be seen that the rotor 1 has a slip ring module 4 which is formed in particular separately from the rotor shaft 2 and connected to the rotor shaft 2 in a rotationally fixed manner, and which has at least two slip rings, namely a first slip ring 5 and a second slip ring 6. Furthermore, the slip ring module 4 has a first conductor 7 which is assigned, for example, to the slip ring 5, and a second conductor 8 which is assigned, for example, to the slip ring 6.The respective conductor 7, 8 is also referred to as a wire or connecting wire or is designed as a wire or as a connecting wire. In the embodiment shown in the figures, the respective conductor 7, 8 is formed from an electrically conductive, metallic material such as copper. For example, the conductors 7 and 8 are formed separately from one another. For example, the respective conductor 7, 8 is formed separately from the slip rings 5 ​​and 6. For example, the conductor 7 is electrically connected to the slip ring 5, and for example, the conductor 8 is electrically connected to the slip ring 6. The conductors 7 and 8 are also formed separately from the excitation winding.

[0030] From Fig. 1 it can be seen that a first contact element 9 is assigned to the conductor 7, and a second contact element 10 is assigned to the conductor s. The respective contact element 9, 10 is formed separately from the conductors 7 and 8. The conductor 7 is electrically connected to the contact element 9, which is electrically connected to the excitation winding. The conductor 8 is electrically connected to the contact element 10, which is electrically connected to the excitation winding. Thus, the conductor

[0031] 7 is electrically connected to the excitation winding via the contact element 9, and the conductor

[0032] 8 is electrically connected to the excitation winding via the contact element 10. The respective contact element 9, 10 is formed separately from the respective conductor 7, 8. For example, the conductor 7 is also mechanically connected to the contact element 9, thus preventing relative movements between the conductor 7 and the contact element 9. For example, the conductor 8 is also mechanically connected to the contact element 10, thereby preventing relative movements between the conductor 8 and the contact element 10.

[0033] In the embodiment shown in the figures, the rotor 1 also has a star disk 11, which for example, in particular directly, rests against an axial end face 22 of the laminated core 3. In this case, the contact elements 9 and 10, for example, are contact elements of the star disk 11. The slip ring 5, for example, directly touches a corresponding, first component of the stator, as a result of which the slip ring 5 forms a sliding contact, also referred to as a sliding contact, with the first component of the stator. As a result, the slip ring 5 is electrically contacted with the first component. Accordingly, the slip ring 6, for example, directly touches a corresponding, second component of the stator, as a result of which the slip ring 6 forms a second sliding contact, also referred to as a second sliding contact, with the second component. As a result, the second slip ring 6 is electrically contacted with the second component.Thus, for example, the following can be provided: An electrical current can be transmitted, for example, from the first component via the first sliding contact to the first slip ring 5. From the first slip ring 5, the electrical current can be transmitted to or onto the conductor 7, from which the electrical current can be transmitted to the contact element 9. From the contact element 9, the electrical current can be transmitted to or onto the excitation winding and thus subsequently flow through the excitation winding in order to drive the rotor 1, for example. From the excitation winding, the electrical current can be transmitted, for example, to the contact element 10 and via this to the conductor 8, from which, for example, the electrical current can be transmitted to the second slip ring 6.For example, the electrical current can be transmitted from the second slip ring 6 to the second component via the second sliding contact, thereby closing or potentially closing an electrical circuit. Thus, for example, the excitation winding can be supplied with electrical current via the contact element 9, the conductor 7, and the slip ring 5, and the electrical current can be discharged from the excitation winding via the contact element 10, the conductor 8, and the slip ring 6.

[0034] The slip ring module 4 is, for example, rotationally fixedly connected to the rotor shaft 2. It is conceivable that the slip ring module 4 is arranged along a wider length of the rotor shaft 2.

[0035] Fig. 3 shows a detail in a schematic perspective view of a first embodiment of the rotor 1. In Fig. 3, the conductor 7 and the corresponding contact element 9 are shown as examples, whereby the previous and following explanations regarding the conductor 7 and the contact element 9 can easily be applied to the conductor 8 and the contact element 10 and vice versa. In order to be able to manufacture the rotor 1 and thus the electrical machine as a whole particularly simply and thus particularly time- and cost-effectively, the contact element 9 itself, that is to say viewed on its own, is free of a surface extending in a plane running perpendicular to the axial direction of the rotor 1 and free of a surface tangent to a plane running perpendicular to the axial direction of the rotor 1. The axial direction of the rotor 1 and thus of the electrical machine as a whole, which coincides with the machine axis of rotation, is shown in Fig.3 by a double arrow 12. The conductor 7 is in direct contact with a contact surface 13 of the contact element 9, whereby the conductor 7 is electrically connected to the contact element 9. The conductor 7 is also mechanically connected to the contact element 9, whereby relative movements between the conductor 7 and the contact element 9 are prevented. For example, the conductor 7 is integrally connected and thus mechanically connected to the contact element 9, wherein, for example, the conductor 7 is soldered to the contact element 9 and thus integrally connected. Alternatively or additionally, for example, the conductor 7 is crimped to the contact element 9, thus mechanically connected to the contact element 9 by crimping.

[0036] In the first embodiment shown in Fig. 3, the contact surface 13 extends exclusively in a plane which runs parallel to the axial direction of the rotor 1. It is preferably provided that the contact surface 13 extends in the axial direction of the rotor 1 over more than two millimeters, in particular over more than three millimeters and very preferably over more than four millimeters. As a result, a particularly extensive axial tolerance compensation can be created between the conductor 7 and the contact element 9, viewed in the axial direction of the rotor 1, so that axial tolerances can be advantageously compensated without excessive, undesirable deformation of the conductor 7 or of a winding wire of the excitation winding forming at least part of the excitation winding.

[0037] The conductor 7 has a first longitudinal region L1 and a second longitudinal region L2, which in this case runs perpendicular to the first longitudinal region L1 and directly adjoins the longitudinal region L1. The longitudinal regions L1 and L2 are preferably formed integrally with one another, thus consisting of a single piece. This means that the longitudinal regions L1 and L2 are not formed separately from one another and connected to one another, but rather the longitudinal regions L1 and L2 are formed from a single piece, thus forming a monoblock formed from a single piece and thus formed in one piece and thus manufactured integrally. In the present case, the longitudinal region L2 extends parallel to the axial direction of the rotor 1, with the longitudinal region L1 extending in the radial direction of the rotor 1, the radial direction of which runs perpendicular to the axial direction of the rotor 1 and is illustrated by a double arrow 14.The second length range L2 is electrically connected to the contact element 9, in this case such that, with respect to the length ranges L1 and L2, only the length range L2 is in direct contact with the contact surface 13. It can also be seen that the length range L2 has a free end E of the conductor 7 and ends at the free end E, at which the conductor 7 ends. In particular, for example, the end E is an end opposite a second end of the conductor 7, wherein the conductor 7 can be electrically connected to the slip ring 5 at its second end.

[0038] Fig. 4 shows a detail in a schematic perspective view of a second embodiment of the rotor 1. In the second embodiment, the contact element 9 has a U-shaped receptacle 15, which is U-shaped when viewed in a plane running perpendicular to the axial direction of the rotor 1. The receptacle 15 is open in a first direction running in the radial direction of the rotor 1, pointing away from the rotor shaft 2 and illustrated by an arrow 16. In the circumferential direction of the rotor 1 running around the axial direction of the rotor 1 and thus around the machine axis of rotation, the circumferential direction of which is illustrated by a double arrow 17, the receptacle 15 is delimited on both sides by the contact element 9, in particular directly.In a second direction running in the radial direction of the rotor 1, opposite the first direction, pointing towards the rotor shaft 2 and illustrated by an arrow 18, the receptacle 15 is delimited, in particular directly, by the contact element 9. The second longitudinal region L2 is arranged in the receptacle 15, in this case such that the longitudinal region L2 completely penetrates the receptacle 15. In both the first embodiment and the second embodiment, axial tolerances between the conductor 7 and the contact element 9 can be compensated for advantageously and as required, whereby the rotor 1 and thus the electrical machine can be manufactured in a time- and cost-effective manner. In the first embodiment and the second embodiment, the conductor 7 has a circular cross-section, although it is of course possible for the conductor 7 to have a cross-section other than a circular cross-section.

[0039] In the second embodiment, the contact element 9 is designed, for example, as a crimping fork having prongs 19 and 20 that protrude from a base region 21 of the crimping fork, in this case such that the prongs 19 and 20 protrude from the base region 21 in the radial direction of the rotor 1 and, in this case, in the first direction (arrow 16). The base region 21 is or forms a base of the crimping fork, wherein the receptacle 15 is delimited in the second direction by the base, thus by the base region 21. In the circumferential direction of the rotor 1, the receptacle 15 is delimited on both sides by the prongs 19 and 20. In the second embodiment, the conductor 7 is or is mechanically connected to the contact element 9 by crimping, in particular by or in such a way that the crimping fork is crimped.

[0040] List of reference symbols

[0041] 1 rotor

[0042] 2 rotor shaft

[0043] 3 sheet packages

[0044] 4 slip ring module

[0045] 5 Slip ring

[0046] 6 slip ring

[0047] 7 ladders

[0048] 8 conductors

[0049] 9 Contact element

[0050] 10 Contact element

[0051] 11 Star disc

[0052] 12 double arrow

[0053] 13 Contact surface

[0054] 14 Double arrow

[0055] 15 recording

[0056] 16 Arrow

[0057] 17 Double arrow

[0058] 18 Arrow

[0059] 19 prongs

[0060] 20 tines

[0061] 21 Basic area

[0062] 22 axial front side

[0063] E free end

[0064] L1 first length range

[0065] L2 second length range

Claims

Patent claims 1. Rotor (1) for an electrical machine of a motor vehicle, with at least one excitation winding, with at least one slip ring (5), and with at least one conductor (7) which is electrically connected to the slip ring (5) and which is electrically connected to a contact element (9) which is formed separately from the conductor (7) and electrically connected to the excitation winding and via which the conductor (7) is electrically connected to the excitation winding, characterized in that the contact element (9) is free of a surface extending in a plane running perpendicular to the axial direction (12) of the rotor (1) and free of a surface tangent to a plane running perpendicular to the axial direction (12) of the rotor (1).

2. Rotor (1) according to claim 1, characterized in that the conductor (7) is in direct contact with a contact surface (13) of the contact element (9), whereby the conductor (7) is electrically connected to the contact element (9).

3. Rotor (1) according to claim 2, characterized in that the contact surface (13) extends in a plane which runs parallel to the axial direction (12) of the rotor (1).

4. Rotor (1) according to claim 2 or 3, characterized in that the contact surface (13) extends in the axial direction (12) of the rotor (1) over more than two millimeters, in particular over more than three millimeters, very preferably over more than four millimeters.

5. Rotor (1) according to one of the preceding claims, characterized in that the conductor (7) has a first length region (L1) and a second length region (L2) which runs obliquely or perpendicularly to the first length region (L1) and ends at a free end (E) of the conductor (7), which ends at the free end (E).

6. Rotor (1) according to claim 5, characterized in that the second length region (L2) is electrically connected to the contact element (9).

7. Rotor (1) according to claim 6 in its reference back via claim 5 to one of claims 2 to 4, characterized in that the second length region (L2) of the conductor (7) is in direct contact with the contact surface (13) of the contact element (9), whereby the conductor (7) is electrically connected to the contact element (9).

8. Rotor (1) according to claim 6, characterized in that the contact element (9) has a C-shaped or U-shaped receptacle (15) which is open in a first direction (16) running in the radial direction (14) of the rotor (1) and pointing away from a rotor shaft (2) of the rotor (1), is delimited on both sides in the circumferential direction (17) of the rotor (1) by the contact element (9) and is delimited by the contact element (9) in a second direction (18) running in the radial direction (14) of the rotor (1) and opposite the first direction (16) and pointing towards the rotor shaft (2), in which receptacle the second length region (L2) is arranged.

9. Rotor (1) according to one of the preceding claims, characterized in that the conductor (7) has a circular cross-section.

10. Motor vehicle, with at least one electric machine by means of which the motor vehicle can be driven, wherein the electric machine has a stator and a rotor (1) according to one of the preceding claims.

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