Rotor comprising an end winding support formed integrally with the rotor shaft

Abstract

The present invention relates to a rotor (105) for an electric motor (102), in particular for a separately excited synchronous motor, comprising a rotor shaft (107) able to be rotated about an axis of rotation of the electric motor (102); a rotor core (115) which is arranged for conjoint rotation with the rotor shaft (107) and in which a plurality of electromagnets having associated windings are fastened; a first end winding support (111) and a second end winding support (117) that are attached to two axially opposite end sides (119, 120) of the rotor core (115) in order to fasten rotor windings (143); wherein the first end winding support (111) and a first axial shaft end section (107A) of the rotor shaft (107) are formed integrally, and / or wherein the second end winding support (117) and a second axial shaft end section, opposite the first axial shaft end section (107A), are formed integrally. The present invention furthermore relates to an electric motor (102) having such a rotor (105), to an electric axle drive having such an electric motor (102), and to an at least partially electrified vehicle (100) having such an electric axle drive.

Description

[0001] Rotor comprising a winding head carrier integrally formed with the rotor shaft

[0002] The present invention relates to a rotor for an electric motor, preferably a separately excited synchronous motor or an electrically excited synchronous motor. In particular, the present invention relates to a rotor comprising a winding head carrier that is integrally formed with the rotor shaft. Furthermore, the present invention relates to an electric motor comprising such a rotor, an electric axle drive with such an electric motor, and an at least partially electrified vehicle with such an electric axle drive.

[0003] Electric axle drives for purely electric vehicles and hybrid electric vehicles are well known from the prior art. Such drive systems generally comprise an electric motor with a stator and a rotor rotatably mounted in the stator. The stator has several stator windings, known as phase strands, each of which is supplied with a corresponding phase current during operation. The phase currents are phase-shifted from one another, such that the energizing of the stator windings produces a rotating magnetic field. The rotor has a rotor shaft and a rotor core fixed to the rotor shaft, in which several magnets are mounted. The magnetic interaction between the rotor magnets on the one hand and the rotating field on the stator side on the other generates a torque that sets the rotor in motion.

[0004] The rotor magnets used are typically permanent magnets or electromagnets integrated into the rotor core. In the former case, the electric motor is a permanent magnet synchronous motor (PSM), while in the latter case, it is a separately excited or electrically excited synchronous motor (FESM or EESM). In the FESM or EESM, the rotor core contains several electromagnets, which are implemented as windings of copper wire. During operation, these rotor windings are energized with a direct current to generate the rotor magnetic field. To ensure the functionality of the electric axle drive, it is essential that the transmission of torque from the rotor core to the rotor shaft occurs reliably over a wide temperature and speed range. It is known from the prior art to achieve this by means of an interference fit between the rotor core and the rotor shaft in the area of ​​the outer surface.However, such measures have disadvantages. In particular, the manufacturing processes used to provide the interference fit or press fit, such as joining techniques, create high mechanical stresses on the inside of the rotor core. This increases the risk of deformation of the rotor core and the rotor shaft. Furthermore, these manufacturing processes, which are also costly, can damage the components used in the rotor core, such as the electromagnets, in the case of FESM and EESM. Additionally, the installation space inside the rotor core is further limited by the electromagnetic design of the rotor and the wall thickness required for mechanical and thermal stability, especially at high speeds and operating temperatures.This makes it difficult to accommodate additional components, such as the device for generating the excitation current for the rotor windings. Furthermore, effective cooling of the rotor core is not possible or only possible to a limited extent with known drive systems, since the inside of the rotor core cannot be directly exposed to coolant, thus preventing direct cooling of the rotor core.

[0005] In view of the aforementioned disadvantages, the object of the present invention is to provide a rotor for an electric motor, in particular an FESM or EESM, in which the aforementioned disadvantages are at least partially overcome.

[0006] According to the invention, the aforementioned problem is solved by the rotor, the electric motor, the electric axle drive, and the vehicle as defined in the independent claims. Advantageous embodiments and further developments of the invention are described in the dependent claims. A rotor for an electric motor is proposed according to a first aspect of the present invention. The electric motor is specifically a separately excited synchronous motor (PESM) or an electrically excited synchronous motor (FESM). The electric motor comprises a stator and the rotor rotatably mounted in the stator. The stator has several stator windings that form phase strands of the multiphase electric motor. During operation, each stator winding is supplied with a corresponding phase current, which is phase-shifted from one another. In this way, the current supplied to the stator windings produces a rotating magnetic field.The phase currents are typically generated by a DC / AC inverter, which converts a DC input voltage provided by a DC power supply (e.g., a battery) into an AC output voltage. The DC / AC inverter comprises several semiconductor-based power switches connected as half-bridges, which are opened and closed according to a predefined duty cycle.

[0007] The rotor has a rotor shaft that can rotate about an axis of rotation and a rotor core that is fixed to the rotor shaft. The rotor shaft extends axially and has a first axial end section and / or a second axial end section located axially opposite the first axial end section. Several magnets are arranged in the rotor core. The magnetic interaction between the rotor magnets on the one hand and the rotating magnetic field on the stator side on the other generates a torque that sets the rotor in motion. In the case of an electric motor that is a FESM or EESM, the rotor core comprises several electromagnets, each formed by winding a corresponding copper wire around a longitudinally extended metal core (in particular, an iron core). During operation, these rotor windings are supplied with a direct current as an excitation current to generate a constant magnetic field.The direct current is typically generated by a DC / DC converter, which converts a DC input voltage generated by a DC power supply (e.g., a battery) into a DC output voltage adapted to the rotor or the desired rotor magnetic field. To secure the rotor windings, the rotor has a first winding head support and a second winding head support. The first winding head support is attached to a first axial end face of the rotor core. The second winding head support is attached to a second axial end face of the rotor core opposite the first axial end face. The first and second winding head supports can be attached directly to the first and second axial end faces of the rotor core, for example, by means of screws, so that the respective winding head support is in direct contact with the corresponding axial end face of the rotor core.Alternatively, a further coating, for example for fastening the winding head carrier, in particular an adhesive layer, can be provided between the respective winding head carrier and the associated axial end side of the rotor core.

[0008] The first winding head support and / or the second winding head support can preferably have a star-shaped cross-section with a base body preferably centered with respect to the axis of rotation of the electric motor and several radial sections projecting from the base body. The base body is preferably axially symmetrical with respect to the axis of rotation of the electric motor, which promotes a uniform force and torque distribution in the rotor in the circumferential direction. For example, the base body can have a circular, hexagonal, or octahedral cross-section. The radial sections serve for attaching the copper wires and are preferably each designed for winding around an associated copper wire to provide the electromagnets housed in the rotor core.In the exemplary and preferred case where both the first and second winding head supports have a star-shaped cross-section and the same number of radial sections, a first radial section of the first winding head support and a second radial section of the second winding head support, axially opposite the first radial section and preferably axially aligned with the latter, preferably form a pair of radial sections around which at least one associated copper wire is wound. This results in a corresponding electromagnet. The radial sections are further preferably provided with an outer boundary, for example in the form of an arc element arranged on a radial outer edge of the respective radial section, and / or with an inner boundary, for example in the form of a radial outer wall of the base body.This limits the copper wires wound around the respective radial sections in the radial direction, so that a fixed arrangement of the electromagnets can be achieved in a simple and safe way.

[0009] According to the invention, the first winding head support and the first axial shaft end section of the rotor shaft are integrally formed. Alternatively or additionally, the second winding head support and the second axial shaft end section are integrally formed.

[0010] Thus, at least one of the two winding head supports is integrally formed with the associated axial shaft end section of the rotor shaft (i.e., located on the same axial end face of the rotor core). Within the scope of the present invention, "integral design" encompasses various implementation methods. For example, the first and / or second winding head support and the associated axial shaft end section can be formed as a single piece (or as a one-piece component). Preferably, the first and / or second winding head support and the associated axial shaft end section are formed from the same starting workpiece, more preferably in a single manufacturing step.Alternatively, the first and / or second winding head support, on the one hand, and the associated axial shaft end section, on the other, can initially exist as separate components, which are subsequently joined together in such a way that, after assembly, both components form a single unit. The respective winding head support can be integrated into the associated axial shaft end section, or vice versa. If both the first and second winding head supports are integrally formed with the respective axial shaft end section, the same design (i.e., as a single component or as a joined unit) or a combination of both designs can be chosen for both.The integral combination of the first and / or second winding head support on the one hand and the first and / or second axial shaft end section on the other, in particular the one-piece component or the unified assembly, can be attached to the first or second axial end face of the rotor core. In this way, a reliable connection between the rotor shaft and the rotor core is achieved according to the invention at the first axial end face and / or the second axial end face of the rotor core, preferably as the only mechanical connection between the rotor shaft and the rotor core. An interference fit between the rotor core and the rotor shaft in the area of ​​their outer surfaces can therefore be completely eliminated. This effectively reduces or even eliminates the mechanical stresses on the inside of the rotor core and thus the risk of deformation of the rotor core and also of the rotor shaft.The manufacturing complexity and the associated production costs of the rotor, and thus also of the entire electric motor, are advantageously reduced.

[0011] The first and / or second winding head support can preferably be made of a metallic material, in particular steel, and more preferably a non-magnetic or austenitic steel. In the case of the aforementioned one-piece construction, the first and / or second axial shaft end section is consequently also made of the same metallic material, in particular steel, such as non-magnetic or austenitic steel.

[0012] According to one embodiment of the present invention, the first winding head support is designed to provide a bearing seat. Alternatively or additionally, the second winding head support is designed to provide a bearing seat. In particular, if only one of the two winding head supports is integrally formed with the associated axial shaft end section (regardless of whether it is a one-piece component or a single assembly), the other winding head support can instead be integrally formed with the bearing seat. Specifically, the winding head support and the bearing seat can be manufactured as a single piece from one workpiece or, alternatively, by joining two separate components. In this way, the bearing seat is integrated into the winding head support (or vice versa), thus eliminating the need for a separate bearing seat.This further reduces the manufacturing effort of the rotor according to the invention.

[0013] According to a further embodiment, the rotor shaft and rotor core are axially aligned without overlap over the entire length of the rotor core. The rotor shaft thus does not extend into the area of ​​an axially extending cavity inside the rotor core. This measure provides a larger installation space inside the rotor core for accommodating additional components, such as the excitation current transmission device. Furthermore, more effective cooling of the rotor core is enabled, since, unlike in prior art drive systems, the inner surface (inner surface) of the rotor core can be directly exposed to the coolant due to the absence of the rotor shaft, thus achieving direct cooling of the rotor core.Alternatively, the rotor shaft can be designed to be axially overlap-free with the rotor core over a partial length of the rotor core, for example by extending the rotor shaft into the inner cavity of the rotor core in the area of ​​the first and / or the second axial end side of the rotor core.

[0014] According to a further embodiment, the first axial shaft end section extends axially from the first winding head support in a first axial direction away from the rotor core. Alternatively or additionally, the second axial shaft end section extends axially from the second winding head support in a second axial direction opposite to the first axial direction. This means that the integral combination of at least one of the two axial shaft end sections and at least one of the two winding head supports has a substantially T-shaped cross-section with respect to an axial sectioning plane.

[0015] According to a further embodiment, the first winding head support and / or the second winding head support comprise a balancing element. The first and / or the second winding head support are fixedly connected to an associated balancing element on one side and on the other. For example, the balancing element can be a balancing ring, attached to the associated winding head support by means of fastening points such as screws distributed along the circumference of the balancing ring.

[0016] According to a further embodiment, the first and second winding head supports are positively connected to each other and / or axially aligned. The positive connection ensures that both winding head supports are rotationally fixed relative to each other, so that the rotor windings remain aligned even at high speeds. This guarantees reliable and low-loss torque transmission between the rotor core and the winding head support with integrated shaft over a wide operating range of the electric motor. Preferably, the positive connection is achieved using dowel pins, heavy-duty clamping pins, screws, and / or clamping sleeves.

[0017] According to a further embodiment, the rotor core is guided by means of one or more bearings attached to the first winding head support and / or the second winding head support. In this way, the rotor core is attached to the rotor shaft, which is integrally formed with the first winding head support and / or the second winding head support, with increased positional stability.

[0018] According to a further embodiment, the first winding head support and / or the second winding head support are positively fixed to the rotor core by means of axial clamping or compression. This measure additionally ensures the alignment of both winding head supports relative to each other and the torque transmission between the rotor core and the rotor shaft. Preferably, the axial clamping or compression is provided by means of screws and / or tie rods.

[0019] According to a further embodiment, the rotor also includes a seal for the rotor core to enable rotor cooling. The seal is preferably formed by overmolding a surface of the rotor core. This results in a high degree of sealing tightness with lower or at least comparable manufacturing effort for the rotor cooling system.

[0020] According to a further embodiment, the overmolding of the rotor core surface is carried out in a single process step to provide injection-molded slot insulation. Preferably, axially extending slots between adjacent poles in the rotor core are overmolded with an injection molding material, parallel to the overmolding of the surface or the inner wall surface of the rotor core. This measure makes it possible to realize the sealing and the slot insulation in a single operation, which increases manufacturing efficiency.

[0021] Furthermore, the winding head support can be designed with channels that allow the cooling fluid to flow within the rotor. Preferably, such channels are formed by a groove in the winding head support that forms a closed channel through axial connection with the rotor core. According to another embodiment, the rotor core comprises an arrangement of axially laminated, electrically insulated sheet metal parts (lamellae), for example, steel sheet metal parts. This creates a laminated laminated core for the rotor core. This design of the rotor core reduces eddy current losses that arise in solid metal parts due to alternating magnetic fields. By using electrically insulated lamellae, the path for such eddy currents is interrupted, which significantly reduces the losses. This also allows for improved heat dissipation from the rotor core, which increases the service life of the electric motor.Preferably, the rotor core has a star-shaped cross-section with several wings for winding copper wires around it, corresponding to the first and / or second winding head support.

[0022] According to a further embodiment, channels for guiding a cooling fluid for rotor cooling can be provided in the winding head supports. Preferably, these channels are designed as grooves open towards the rotor core, which form closed channels when connected to the rotor core.

[0023] According to a further aspect of the present invention, an electric motor, in particular a separately excited synchronous motor, is proposed, comprising a stator and a rotor according to one of the embodiments described in this disclosure. According to yet another aspect of the present invention, an electric axle drive for an at least partially electrified vehicle is proposed, comprising such an electric motor and an inverter for supplying power to the electric motor. According to yet another aspect of the present invention, a vehicle with such an electric axle drive is proposed.

[0024] This results in the same advantages already described in connection with the rotor according to the invention also for the electric motor according to the invention, the electric axle drive according to the invention and the vehicle according to the invention.

[0025] The features of the claims and the features described above and below with reference to the drawings complement each other. Features that become apparent in the exemplary embodiments, both individually and in each combination of features, advantageously further develop the subject matter of the claims and also the embodiments described above.

[0026] The invention is explained below by way of example with reference to embodiments shown in the figures. The figures show:

[0027] Fig. 1 shows a schematic representation of a vehicle comprising an electric axle drive;

[0028] Fig. 2 shows a schematic representation of an electric motor in the electric axle drive with a stator and a rotor;

[0029] Fig. 3 shows a schematic representation of the rotor according to one embodiment in a side sectional view;

[0030] Fig. 4 shows a perspective view of a first winding head support for the rotor according to a further embodiment;

[0031] Fig. 5 shows a perspective view of a second winding head support for the rotor according to the further embodiment;

[0032] Fig. 6 shows a representation of the rotor according to the further embodiment in a side sectional view;

[0033] Fig. 7 shows a representation of the rotor according to the further embodiment in a first perspective view;

[0034] Fig. 8 shows a representation of the rotor according to the further embodiment in a second perspective view.

[0035] Identical objects, functional units, and comparable components are designated by the same reference numerals across all figures. These objects, functional units, and comparable components are identical with respect to their technical characteristics, unless explicitly or implicitly stated otherwise in the description. Fig. 1 shows a schematic representation of a vehicle 100 that is at least partially electrified. The vehicle 100 can be a purely electric vehicle or a hybrid vehicle. The vehicle 100 is equipped with an electric axle drive comprising an electric motor 102, a DC / AC inverter 106, and a gearbox 112. The inverter 106 is arranged or connected between the traction battery 106 and the electric motor 102 for the purpose of converting a DC input voltage provided by a traction battery 104 into an AC output voltage for feeding into the electric motor 102.For this purpose, the inverter 106 has a plurality of power switches (not shown in detail here) that form a bridge circuit with several half-bridges and are controlled by control signals from a control unit 108 in order to generate multiple phase currents for the phase strands of a stator 103 (see Fig. 2) of the electric motor 102 by opening and closing the power switches. The control signals are preferably configured to switch the power switches of the inverter 106 according to pulse width modulation (PWM). The phase currents cause a rotating magnetic field in the region of the stator, which interacts with the magnetic field of a rotor 105 (see Fig. 2) of the electric motor 102, thereby generating a torque.The transmission 112, which preferably has a speed-reducing transmission, is designed to transmit the torque of the electric motor 102 to an axle 110, which here is by way of example a rear axle of the vehicle 100, and finally to wheels 114, here by way of example rear wheels.

[0036] The electric motor 102 is designed, in particular, as a separately excited synchronous machine (FESM), preferably as an electrically excited (or inductively electrically excited) synchronous machine (EESM or IEESM). For this purpose, the rotor 105 uses an arrangement of electromagnets with rotor windings, which are supplied with a DC excitation current of suitable magnitude. The DC excitation current can preferably be provided by means of a DC / DC converter, not shown in detail here, which converts a DC input voltage, for example, supplied by the drive battery 104, into a DC output voltage adapted to the desired rotor magnetic field. As shown schematically in Fig. 2, the rotor 105, which is rotatably mounted about a rotational axis 109 in the electric motor 102, in particular in the stator 103, has a rotor shaft 107. Furthermore, the rotor 105 has, as shown in Fig.Figure 3, according to an exemplary embodiment shown purely schematically, comprises a rotor core 115 which is rotationally fixed to the rotor shaft 107. The rotor core 115 extends between a first axial end face 119 and a second axial end face 120 opposite the first axial end face 119. Furthermore, the rotor core 115 defines a radially inner cavity 124, which can, for example, serve to accommodate other components, such as the transformer for providing the DC excitation current for the rotor magnets.

[0037] A first winding head support 111 is attached to the first axial end face 119 of the rotor core 115. A second winding head support 117 is also attached to the second axial end face 120 of the rotor core 115. Both the first winding head support 111 and the second winding head support 117 are designed for attaching copper wires from which rotor windings 143 (see Figs. 7-8) are formed for the electromagnets of the electric motor 100, which is configured as an externally excited or electrically excited synchronous machine. The first winding head support 111 is integrally formed with a first axial shaft end section 107A of the rotor shaft 107. Preferably, the first winding head support 111 and the first axial shaft end section 107A are formed as a single piece. This results in a one-piece component 113, which can be attached as an independent component to the first axial end face 119 of the rotor core 115. The one-piece component 113 has, as shown in Fig.Figure 3 shows, by way of example, a T-shaped cross-section, which, however, is not limiting for the present invention. The integral design of the first winding head support 111 with the first axial shaft end section 107A is not limited to a one-piece design. Alternatively, the first winding head support 111 and the first axial shaft end section 107A can initially be provided as separate components and then joined together to form a unified assembly 113, which can then be attached to the first axial end face 119 of the rotor core 115. A first bearing 122, which is preferably designed as a radial bearing in this case, is attached to the first axial shaft end section 107A of the rotor shaft 107. The second winding head support 117 is, as shown in Fig.Figure 3 shows, purely by way of example, a bearing seat (not shown in detail here) for mounting a second bearing 123, which is also preferably designed as a radial bearing, integrally formed. However, this is not limiting for the present invention. It is conceivable, analogous to the integral combination of the first winding head support 111 and the first axial shaft end section 107A, to form the second winding head support 117 and a second axial shaft end section (not shown here) opposite the first axial shaft end section 107A integrally, in particular as a single piece.

[0038] The first and / or second winding head support 111, 117 can preferably be made of a metallic material, in particular steel, more preferably a non-magnetic or austenitic steel. In the preferably shown case of the one-piece construction, the first axial shaft end section 107A is made of the same metallic material, in particular steel, such as non-magnetic or austenitic steel.

[0039] As can be seen schematically and purely by way of example in Fig. 3, the rotor shaft 107 preferably does not extend into the radially inner cavity 124 of the rotor core 115. This means that the rotor shaft 107 is axially free of overlap with the rotor core 115 over its entire length. This advantageously provides additional installation space in the radially inner cavity 124 for accommodating components. Furthermore, the rotor core 115 can be directly supplied with a coolant, thus enabling direct rotor cooling. However, this is not a limitation for the present invention. Alternatively, the rotor shaft 107 can be axially free of overlap with the rotor core 115 over a partial length of the rotor core 115.This can be achieved, for example, by extending the first axial shaft end section 107A beyond the first axial end face 119 of the rotor core 115 along an inner wall surface of the rotor core 115 further into the interior of the cavity 124. This can also apply, correspondingly, to the second axial shaft end section in the case (not shown in detail here) where the second axial shaft end section is located at the second axial end face 120 of the rotor core 115, with respect to the second axial end face 120. The first winding head support 111 and the second winding head support 117 are positively connected to each other. The positive connection 121 between the two winding head supports 111 and 117, shown purely schematically and by way of example in Fig. 3, ensures that both winding head supports 111 and 117 are arranged in a rotationally fixed manner relative to each other. This ensures that the rotor windings remain aligned with each other even at high speeds.This ensures reliable and low-loss torque transmission between the rotor core 115 and the rotor shaft 107 over a wide operating range of the electric motor 100. Preferably, the positive locking is achieved using dowel pins, heavy-duty clamping pins, screws and / or clamping sleeves.

[0040] Furthermore, the first winding head support 111 and the second winding head support 117 are fixed to the rotor core 115 by axial clamping. This measure additionally ensures the alignment of both winding head supports 111 and 117 relative to each other and the torque transmission between the rotor core 115 and the rotor shaft 107. Preferably, the axial clamping is provided by means of screws and / or tie rods.

[0041] Figures 4 and 5 show the first winding head support 111 and the second winding head support 117, respectively, according to a further embodiment. Both winding head supports 111 and 117 have a star-shaped cross-section and each has a base body 125, 131 and several (here, for example, six) extensions of the base body.

[0042] The radial sections 126 and 132 protrude from the 125 and 131. The radial sections 126 and 132 are evenly distributed in the circumferential direction, such that adjacent radial sections

[0043] The radial sections 126, 132 enclose the same angle. Each radial section is bounded radially on both its inner and outer sides. On the inner side, each radial section 126, 132 is bounded by an outer wall 127, 133 of the associated base body 125, 131, while on the outer side, each is bounded by an inner wall of an arc element 128, 134 arranged at a radial outer edge of the respective radial section. This bounds the copper wires wound around the respective radial sections 126, 132 radially, thus enabling a simple and safe fixed arrangement of the electromagnets. The first axial shaft end section 107A, which in this example is formed in one piece with the first winding head carrier 111, extends centrally perpendicularly from a side facing away from the rotor core 115 to the base body 125 associated with the first winding head carrier 111.The base body 131 associated with the second winding head support 117 has a centrally arranged opening 137 in which the bearing seat, in particular a radial bearing seat, is formed. Thus, in Figures 4 and 5, a single component 113 is shown, consisting of the respective winding head support 111, 117 on the one hand, and the first axial shaft end section 107A or the bearing seat on the other. Both the first winding head support 111 and the second winding head support 117 have several screw openings 129, 130, 135, 136, which are provided in the base body 125 and in the arc elements 128, 134, respectively.

[0044] In Fig. 6, the rotor 105 according to a further embodiment is shown in a side sectional view, in which both uniform components from Figs. 4 and 5 are axially attached to the rotor core 115 at its ends. Figs. 7-8 show the rotor 105 from Fig. 6 in two different perspective views. Here, the rotor core 115 preferably has a plurality of axially laminated sheet metal parts 125a, 125b, 125c, 125d, 125e (see Fig. 8) and thus a laminated sheet metal stack. Corresponding to the winding head supports 111, 117, the sheet metal parts 125a, 125b, 125c, 125d, 125e are each also provided with a star-shaped cross-section. Each sheet metal part 125a, 125b, 125c, 125d, 125e thus has a plurality of (here, for example, six) radial elements, which are not shown in detail here. Radially oriented radial elements form a wing of the laminated sheet metal stack.Copper wires are wound around each blade and around the radially aligned radial sections of both winding head supports 111, 117 to provide the rotor windings 143 and, consequently, the electromagnets for the electric motor 100, which here is a separately excited synchronous machine. Electrical insulation 142 is arranged between adjacent blades of the laminated core. The non-overlapping arrangement between the rotor core 115 and the rotor shaft 107 provides better protection for the electrical insulation 142 against damage.

[0045] The axial compression between the respective winding head carrier 111, 117 and the rotor core 115 or its end faces 119, 120 is achieved, for example, by means of the screws 138, 139 received in the screw openings 129, 130, 135, 136. Additionally, the positive-locking connection 121 between the two winding head carriers 111, 117 is preferably realized in the form of screw connections. Furthermore, a balancing element 140, 141, preferably in the form of a balancing ring, is attached to both the first axial end face 119 and the second axial end face 120 of the rotor core 115 by means of the screws 138, 139.

[0046] Reference symbol list

[0047] vehicle

[0048] electric motor

[0049] stator

[0050] drive battery

[0051] rotor

[0052] DC / AC inverter

[0053] Rotor shaft A first axial shaft end section

[0054] Control unit

[0055] axis of rotation

[0056] Axle / Rear axle first winding head carrier

[0057] transmission

[0058] Wheels

[0059] Rotor core, second winding head support, first axial end face, second axial end face, positive locking connection, first bearing, second bearing, radial inner cavity

[0060] Base body a laminated sheet metal part b laminated sheet metal part c laminated sheet metal part d laminated sheet metal part e laminated sheet metal part

[0061] radial section

[0062] Outer wall, curved element, screw opening, screw opening, base body, radial section, outer wall, curved element, screw opening, screw opening, central opening, screw, screw, balancing part / balancing ring, balancing part / balancing ring, electrical insulation, rotor winding

Claims

Patent claims 1. Rotor (105) for an electric motor (102), in particular for a separately excited synchronous motor, comprising: - a rotor shaft (107) which is rotatable about an axis of rotation of the electric motor (102); - a rotor core (115) which is arranged in a rotationally fixed manner relative to the rotor shaft (107) and in which several electromagnets with associated windings are attached; - a first winding head support (111 ) and a second winding head support (117) which are attached for fastening rotor windings (143) to two axially opposite end faces (119, 120) of the rotor core (115); wherein the first winding head support (111 ) and a first axial shaft end section (107A) of the rotor shaft (107) are integrally formed, and / or wherein the second winding head support (117) and a second axial shaft end section opposite the first axial shaft end section (107A) are integrally formed.

2. Rotor (105) according to claim 1, wherein the first and / or second winding head carrier (111, 117) are formed in one piece with the first and / or second axial shaft end section (107A).

3. Rotor (105) according to claim 1 or 2, wherein the first and / or second winding head carrier (117) provides a bearing seat.

4. Rotor (105) according to one of the preceding claims, wherein the rotor shaft (107) is formed axially without overlap with the rotor core (115) over a total length or a partial length of the rotor core (115).

5. Rotor (105) according to claim 4, wherein the first axial shaft end section (107A) extends axially from the first winding head support (111) in a direction away from the rotor core (115), and / or wherein the second axial shaft end section extends axially from the second winding head support (117) in a further direction away from the rotor core (115).

6. Rotor (105) according to one of the preceding claims, wherein the first winding head carrier (111) and / or the second winding head carrier (117) is a balancing element. (140, 141) include or are fixedly connected to a balancing element (140, 141).

7. Rotor (105) according to one of the preceding claims, wherein the first winding head carrier (111 ) and the second winding head carrier (117) are positively connected to each other and / or rotationally aligned to each other, wherein the positive connection is preferably provided by dowel pins, heavy-duty clamping pins, screws and / or clamping sleeves.

8. Rotor (105) according to one of the preceding claims, wherein the rotor core (115) is guided by means of one or more bearings (123) attached to the first winding head support (111) and / or to the second winding head support (117).

9. Rotor (105) according to one of the preceding claims, wherein the first winding head support (111 ) and the second winding head support (117) are connected to each other in a positionally fixed manner and / or aligned to each other by axial clamping or compression, wherein the axial clamping or compression is preferably provided by means of screws and / or tie rods.

10. Rotor (105) according to one of the preceding claims, further comprising a seal of the rotor core (115), which is preferably formed by overmolding a surface of the rotor core (115) which comprises at least an inner wall surface of the rotor core (115).

11. Rotor (105) according to claim 10, wherein the overmolding of the surface of the rotor core (115) is carried out in a common process step to provide injection-molded slot insulations.

12. Rotor (105) according to one of the preceding claims, wherein the rotor core (115) comprises an arrangement of sheet metal parts (125a-e) laminated in an axial direction, preferably wherein the rotor core (115) has a star-shaped cross-section with several vanes for winding copper wires around it.

13. Electric motor (102) for an at least partially electrified vehicle (100), in particular a separately excited synchronous motor, comprising a rotor (105) according to one of claims 1 to 12, and a stator (103).

14. Electric axle drive for an at least partially electrified vehicle (100), comprising an electric motor (102) according to claim 13 and an inverter (106) for powering the electric motor (102).

15. Vehicle (100) comprising an electric axle drive according to claim 14.

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