Rotor for an electric machine and electric machine

Abstract

A rotor (100) for an electric machine (200) comprising a hollow rotor shaft (10) and a laminated core (11) arranged on the rotor shaft (10), wherein the laminated core (11) comprises at least a first coolant guide arrangement (12), wherein the first coolant guide arrangement (12) comprises at least a first coolant guide arrangement (13) and a second coolant guide arrangement (14), wherein the first coolant guide arrangement (13) has a plurality of first coolant channels (17) extending through the laminated core (11) from a first end face (15) of the laminated core (11) to a second end face (16) of the laminated core (11) at a first radius (19), and wherein the second coolant guide arrangement (14) has a plurality of second coolant channels (18) extending through the laminated core (11) from the second end face (16) of the laminated core (11) to the first end face (15) of the laminated core (11) at a second radius (21) features, characterized bythat the first coolant guide arrangement (13) comprises a first coolant collection device (28) arranged at the first end side (15) at the first radius (19), wherein the first coolant collection device (28) is arranged and configured such that coolant collected by the first coolant collection device (28) can flow into the first coolant channels (17), and that the second coolant guide arrangement (14) comprises a second coolant collection device (30) arranged at the second end side (16) at the second radius (21), wherein the second coolant collection device (30) is arranged and configured such that coolant collected by the second coolant collection device (30) can flow into the second coolant channels (18).

Description

[0001] The present invention relates to a rotor for an electrical machine comprising a hollow rotor shaft and a laminated core arranged on the rotor shaft, wherein the laminated core comprises at least one first coolant guide arrangement, wherein the first coolant guide arrangement comprises at least one first coolant guide arrangement and a second coolant guide arrangement, wherein the first coolant guide arrangement has a plurality of first coolant channels running through the laminated core from a first end side of the laminated core to a second end side of the laminated core at a first radius, and wherein the second coolant guide arrangement has a plurality of second coolant channels running through the laminated core from the second end side of the laminated core to the first end side of the laminated core at a second radius.

[0002] Furthermore, the present invention relates to an electric machine with a rotor and a motor vehicle comprising an electric machine.

[0003] Electromagnetic conversion losses occur in electrical machines during operation. Magnetization losses in the rotor heat the laminated core. Furthermore, electrical conduction losses occur in the current-carrying conductors of the rotor or stator coils. These electromagnetic conversion losses increase the rotor temperature in the form of heat loss. The increase in rotor temperature ceases when the heat loss equals the heat dissipated in thermodynamic equilibrium.

[0004] In the prior art, it is known to provide coolant channels in the rotor's laminated core for cooling the rotor of an electrical machine. A coolant, such as oil, flows through the coolant channels. The oil flowing through the coolant channels absorbs the lost heat, thereby cooling the rotor. Heat transfer from the rotor to the coolant is limited by the small surface area of ​​the cooling channels and the inadequate connection to the heat sources. Furthermore, interfering contours or materials with a low thermal conductivity coefficient can lead to insufficient heat transfer of the lost heat from the rotor to the oil.

[0005] An electric machine with rotor cooling is known from DE 10 2021 204 671 A1. The electric machine comprises a stator and a rotor, wherein the rotor has rotor laminations mounted on a shaft. The shaft includes an oil channel, and the rotor laminations have channels parallel to the axis of the shaft and cover plates at their ends. The oil channel has transverse bores arranged on the front side of the electric machine in axially spaced planes.

[0006] JP 2019-187063 A discloses an electric machine comprising a first flow path provided in a shaft, second and third flow paths formed in a rotor core, a fourth flow path formed in the rotor core, a fifth flow path formed in a first end plate and connecting the first flow path and the second flow path, and a U-shaped channel formed on a second end plate and connecting the third flow path and the fourth flow path. The first end plate is formed with a first outlet port for discharging refrigerant or coolant passed through the fourth flow path to the outside of the rotor, and the second end plate is formed with a second outlet port for discharging the coolant passed through the second flow path to the outside of the rotor.

[0007] From DE 10 2019 217 510 A, a rotor for an electric machine is known, comprising a rotor longitudinal axis, a rotor base body extending along the rotor longitudinal axis, at least one first balancing disk arranged in the axial direction next to a first base body side of the rotor base body, wherein a coolant cavity for conducting coolant along the rotor longitudinal axis is formed in the rotor base body, wherein the coolant cavity has a coolant inlet for introducing the coolant into the coolant cavity and a coolant outlet for discharging the coolant from the coolant cavity.

[0008] Furthermore, DE 10 2019 124 209 discloses a cooling system for an electric motor comprising a stator with winding heads and a rotor with a rotor shaft, wherein the rotor has at least one end plate, wherein the at least one end plate has a first section, wherein the at least one end plate is conically formed around the rotor shaft in the first section, wherein the rotor comprises a laminated core and the at least one end plate has at least one outlet opening which is configured to discharge a coolant from the laminated core of the rotor, wherein the at least one outlet opening is configured to specifically fan out and atomize the outflowing coolant, wherein the at least one end plate is designed such that the discharge of a jet of coolant leads to an axial fanning out of the jet and a radial inner side of the winding heads of the stator is uniformly wetted and cooled.

[0009] The present invention is based on the object of providing a rotor for an electrical machine which can be effectively cooled in order to generate a homogeneous temperature field in the rotor.

[0010] To achieve the object underlying the invention, a rotor for an electrical machine is proposed, comprising a hollow rotor shaft and a laminated core arranged on the rotor shaft, wherein the laminated core comprises at least one first coolant guide arrangement, wherein the first coolant guide arrangement comprises at least one first coolant guide arrangement and a second coolant guide arrangement, wherein the first coolant guide arrangement has a plurality of first coolant channels running through the laminated core from a first end side of the laminated core to a second end side of the laminated core at a first radius, and wherein the second coolant guide arrangement has a plurality of second coolant channels running through the laminated core from the second end side of the laminated core to the first end side of the laminated core at a second radius, wherein it is further providedthat the first coolant guide arrangement comprises a first coolant collecting device arranged on the first end side at the first radius, wherein the first coolant collecting device is arranged and designed such that a coolant collected by the first coolant collecting device can flow into the first coolant channels, and that the second coolant guide arrangement comprises a second coolant collecting device arranged on the second end side at the second radius, wherein the second coolant collecting device is arranged and designed such that a coolant collected by the second coolant collecting device can flow into the second coolant channels.,

[0011] The first coolant guide arrangement thus comprises at least a first coolant guide arrangement and a second coolant guide arrangement. Each of the coolant guide arrangements comprises a plurality of coolant channels running through the laminated core. The first coolant channels of the first coolant guide arrangement run through the laminated core from a first end side to a second end side of the laminated core and are arranged at or on a first radius of the rotor. The second coolant guide arrangement comprises a plurality of second coolant channels running through the laminated core from the second end side of the laminated core to the first end side and are arranged at or on a second radius. The first radius and the second radius are measured radially outwards from a rotational axis of the rotor.

[0012] The first coolant channels of the first coolant guide arrangement can be arranged on the first radius, distributed uniformly in a circumferential direction or over the circumference of the rotor, in particular of the laminated core. This means that, when viewed from the first end side or the second end side along the rotational axis of the rotor, the first coolant channels are arranged essentially on a circle with the first radius. Accordingly, the second coolant channels of the second coolant guide arrangement can also be arranged on the second radius, distributed uniformly over the circumference of the rotor.

[0013] The first coolant guide arrangement comprises a first coolant collecting device, and the second coolant guide arrangement comprises a second coolant collecting device. The first coolant collecting device, like the first coolant channels, is also arranged on or at the first radius. The second coolant collecting device is arranged on or at the second radius, corresponding to the second coolant channels.

[0014] The first coolant collecting device is arranged and configured such that a coolant collected by the first coolant collecting device can flow into the first coolant channels. This means that the first coolant collecting device is fluidically connected to the first coolant channels. Similarly, the second coolant collecting device is arranged and configured such that a coolant collected by the second coolant collecting device can flow into the second coolant channels. This means that the second coolant collecting device is fluidically connected to the second coolant channels.

[0015] It is preferably provided that the first coolant collecting device is arranged and configured to collect a coolant during operation of an electrical machine provided with the rotor and to introduce it into the first coolant channels. Accordingly, the second coolant collecting device is arranged and configured to collect a coolant during operation of an electrical machine provided with the rotor and to introduce it into the second coolant channels.

[0016] Since the first coolant collecting device is arranged on the first end side of the laminated core, a coolant collected by the first coolant collecting device flows from the first end side of the laminated core through the first coolant channels to the second end side during operation of an electrical machine provided with the rotor. A coolant collected by the second coolant collecting device during operation of the electrical machine flows correspondingly through the second coolant channels from the second end side of the laminated core to the first end side. The coolant thus flows through the laminated core in at least two different directions.

[0017] The first coolant guide arrangement forms a first cooling stage. The second coolant guide arrangement forms a second cooling stage.

[0018] Preferably, the second radius is larger than the first radius.

[0019] In other words, the first coolant channels of the first coolant guide arrangement are located closer to the rotor's rotational axis than the second coolant channels of the second coolant guide arrangement. Thus, during operation of an electric machine equipped with the rotor, the coolant flows through the laminated core at multiple radii. This allows the coolant to effectively absorb heat loss and establish a homogeneous temperature field within the rotor.

[0020] It is preferably provided that the first coolant channels each have an inlet opening in the first end side of the laminated core and an outlet opening in the second end side of the laminated core, and that the second coolant channels each have an inlet opening in the second end side of the laminated core and an outlet opening in the first end side of the laminated core.

[0021] Thus, it is further preferably provided that the first coolant collecting device is fluidically connected to the inlet openings of the first coolant channels in the first end side of the laminated core, and that the second coolant collecting device is fluidically connected to the inlet openings of the second coolant channels in the second end side of the laminated core. A coolant introduced into the first coolant channels via the first coolant collecting device through the inlet openings of the first coolant channels then exits from the outlet openings of the first coolant channels after flowing through the laminated core. Correspondingly, a coolant collected by the second coolant collecting device exits through the inlet openings of the second coolant channels, and after flowing through the laminated core, the coolant exits from the outlet openings of the second coolant channels.

[0022] It is particularly preferably provided that the hollow rotor shaft has substantially radially aligned coolant outlet openings, and that the first coolant collecting device of the first coolant guide arrangement is arranged and designed to collect a coolant emerging from the coolant outlet openings of the rotor shaft, and / or that the second coolant collecting device is arranged and designed to collect a coolant emerging from the first coolant channels of the first coolant guide arrangement at the second end side.

[0023] Preferably, the substantially radially aligned coolant outlet openings of the rotor shaft are located axially relative to the rotational axis of the rotor approximately at the first end side of the laminated core. During operation of an electrical machine equipped with the rotor, a coolant, for example oil, is introduced into the hollow rotor shaft to cool the rotor. Due to the centrifugal forces occurring during operation of the electrical machine, the coolant emerges radially from the coolant outlet openings of the hollow rotor shaft and is thrown outwards in the radial direction. The coolant emerging from the coolant outlet openings of the rotor shaft strikes the first coolant collecting device of the first coolant guide arrangement, is collected by it and is introduced into the first coolant channels, preferably through the inlet openings of the first coolant channels.The coolant flowing from the first end side to the second end side through the first coolant channels of the laminated core then exits at the second end side, preferably through the outlet openings of the first coolant channels. Due to the centrifugal forces acting on the coolant exiting from the first coolant channels, the coolant is thrown radially outwards after exiting the first coolant channels and is then collected by the second coolant collecting device of the second coolant conducting device and introduced into the second coolant channels by the second coolant collecting device, preferably through the inlet openings. The coolant thus introduced into the second coolant channels then flows through the laminated core from the second end side to the first end side and subsequently exits at the first end side of the laminated core, preferably from the outlet openings of the second coolant channels.Due to the continuing centrifugal forces, the coolant escaping from the second coolant channels is again thrown radially outward. The coolant thus first flows through the hollow rotor shaft, then through the first coolant channels at the first radius, and then through the second coolant channels at the second radius. By flowing through the rotor's laminated core several times, the coolant can absorb a greater amount of heat, enabling effective cooling of the rotor.

[0024] The first coolant channels and / or the second coolant channels have a flow resistance. The centrifugal forces imposed on the coolant by the rotation of the rotor in the electric machine cause a centrifugal pressure, which overcomes the flow resistance and thus pushes the coolant collected by the first coolant collection device into the first coolant channels or pushes the coolant collected by the second coolant collection device into the second coolant channels.

[0025] It is further provided that the first coolant guide arrangement has a first coolant discharge device arranged on the second end side at the first radius, which is designed to deflect a coolant emerging from the first coolant channels radially outwards, and that the second coolant guide arrangement has a second coolant discharge device arranged on the first end side at the second radius, which is designed to deflect a coolant emerging from the second coolant channels radially outwards.

[0026] The first coolant dispensing device, like the first coolant channels and the first coolant collecting device, is located on or at the first radius. This first coolant dispensing device is fluidly connected to the first coolant channels, preferably to the outlet openings of the first coolant channels, such that a coolant flowing from the first end side to the second end side flows from the outlet openings of the first coolant channels into the first coolant dispensing device and is deflected outward by the first coolant dispensing device. The second coolant dispensing device, like the second coolant channels and the second coolant collecting device, is located on or at the second radius.The second coolant dispensing device is fluidically connected to the second coolant channels, preferably to the outlet openings of the second coolant channels, so that a coolant flowing from the second end side to the first end side flows from the outlet openings of the second coolant channels into the second coolant dispensing device and is deflected outwards by the second coolant dispensing device.

[0027] The first coolant dispensing device serves, in particular, to deflect the coolant emerging from the first coolant channels radially outward by 90°. Due to the deflection of the coolant, in particular by 90°, by means of the first coolant dispensing device, the coolant emerging from the first coolant channels is specifically directed toward the second coolant collecting device, where it can be collected and subsequently introduced into the second coolant channels.

[0028] It is therefore preferably provided that the first coolant dispensing device and the second coolant collecting device are arranged relative to one another in such a way that a coolant deflected radially outward by the first coolant dispensing device is collected by the second coolant collecting device.

[0029] It is further advantageously provided that the first coolant collecting device and / or the second coolant collecting device is designed as a groove or channel running in a circumferential direction of the laminated core and opening radially inwards.

[0030] The first coolant collecting device thus revolves around the rotational axis of the rotor on the first radius or at a distance of the first radius and is designed as a groove or channel arranged on the first end side of the laminated core. The groove or channel is open radially inwards. As a result, coolant escaping through the coolant outlet openings of the hollow rotor shaft can be collected by the first coolant collecting device designed as a channel or groove. During operation of an electrical machine equipped with the rotor, the coolant collected by the channel or groove is distributed evenly in the groove or channel due to centrifugal forces and is introduced into the first coolant channels.

[0031] The second coolant collecting device revolves around the rotor's rotational axis on the second radius or at a distance of the second radius and is designed as a groove or channel arranged on the second end side of the laminated core. The groove or channel is open radially inward. This allows coolant escaping from the first coolant channels to be collected by the second coolant collecting device designed as a channel or groove. During operation of an electrical machine equipped with the rotor, the coolant collected by the channel or groove is evenly distributed in the groove or channel due to centrifugal forces and is fed into the second coolant channels.

[0032] It is advantageously provided that the first coolant collecting device and / or the second coolant collecting device, in particular the groove or channel, have guide devices, in particular guide vanes.

[0033] By arranging guide devices, particularly designed as guide vanes, in the groove or channel, the coolant collected by the groove or channel can be introduced in a targeted manner, preferably through the inlet openings, into the first coolant channels or the second coolant channels.

[0034] It is preferably provided that the first coolant dispensing device and / or the second coolant dispensing device comprises radially outwardly directed, preferably angled, tubes or pipes, wherein a respective tube or pipe of the first coolant dispensing device is fluidically connected to one of the first coolant channels, and wherein a respective tube or pipe of the second coolant dispensing device is fluidically connected to one of the second coolant channels.

[0035] The tubes or pipes of the first coolant dispensing device and the second coolant dispensing device are each fluidically connected to a first coolant channel or second coolant channel associated with the respective tube or pipe. This means that the respective tube or pipe is fluidically connected, in particular, to the outlet openings of the first coolant channels or the second coolant channels or is arranged on them. The tubes or pipes of the first coolant dispensing device and / or the second coolant dispensing device can be formed in material projections on the first end side or the second end side of the laminated core.The tubes or pipes are in particular bent or angled by 90°, so that coolant emerging axially from the first coolant channels or the second coolant channels flows into the respective tubes or pipes and is deflected outwards by 90° in the radial direction.

[0036] Further preferably, the tube or pipe fluidically connected to one of the first coolant channels comprises a first tube or pipe section aligned substantially axially and in alignment with the first coolant channel and a second tube or pipe section aligned substantially radially outward, in particular angled by 90° to the first tube or pipe section.

[0037] Accordingly, the tube or pipe fluidically connected to one of the second coolant channels comprises a first tube or pipe section aligned substantially axially and in alignment with the second coolant channel and a second tube or pipe section aligned substantially radially outward, in particular angled by 90° to the first tube or pipe section.

[0038] It can further be provided that the second pipe or tube section of the pipe or tube fluidically connected to one of the first coolant channels opens into the second coolant collecting device of the second coolant guide arrangement.

[0039] If, as explained further below, the first coolant guide arrangement has a third coolant guide arrangement, it can be provided accordingly that the second pipe or tube section of the pipe or tube fluidically connected to one of the second coolant channels opens into a third coolant collecting device of the third coolant guide arrangement.

[0040] Furthermore, it can preferably be provided that the respective second pipe or tube sections are arranged running in a closure or balancing disk.

[0041] The arrangement of the second tube or pipe sections in a cover or balancing disc can be particularly advantageous in a rotor for a separately excited synchronous machine (FSM). In an FSM machine, the rotor has excitation windings that can protrude axially beyond the end faces of the laminated core. The excitation windings protruding beyond the end faces of the laminated core can hinder the transfer of coolant from the coolant discharge devices to the coolant collection devices. In this case, the second tube or pipe sections can be arranged in a cover or balancing disc so that the excitation windings do not impede the transfer of coolant from the coolant discharge devices to the coolant collection devices.

[0042] If the second pipe or tube sections are arranged in a closure or balancing disc, it is further advantageous to provide, in particular, axial pressure equalization channels, which open into the pipe or tube at a suitable location, in particular into the second pipe or tube section. The pressure equalization channels serve to equalize the atmospheric pressure of the otherwise closed pipes or tubes, especially if they run in the closure or balancing disc.

[0043] The laminated core is preferably subjected to axial compression on both sides. The axial compression forces the individual laminations of the laminated core together, reducing or preventing leaks from the first coolant channels and / or the second coolant channels.

[0044] Furthermore, it can be provided that the first coolant guide arrangement comprises a third coolant guide arrangement, wherein the third coolant guide arrangement has a plurality of third coolant channels passing through the laminated core from the first end side of the laminated core to the second end side of the laminated core at a third radius, wherein preferably the first coolant guide arrangement comprises a fourth coolant guide arrangement, wherein the fourth coolant guide arrangement has a plurality of fourth coolant channels passing through the laminated core from the second end side of the laminated core to the first end side of the laminated core at a fourth radius, wherein further preferably the first coolant guide arrangement comprises a fifth coolant guide arrangement,wherein the fifth coolant guide arrangement has a plurality of fifth coolant channels passing through the laminated core from the first end side of the laminated core to the second end side of the laminated core at a fifth radius.

[0045] In other words, in addition to the first cooling stage formed by the first coolant guide arrangement and the second cooling stage formed by the second coolant guide arrangement, further cooling stages can be provided, which are formed by the third coolant guide arrangement, the fourth coolant guide arrangement, or the fifth coolant guide arrangement, respectively. In particular, it is provided that the third radius is larger than the second radius, that the fourth radius is larger than the third radius, and that the fifth radius is larger than the fourth radius. In principle, however, more than five cooling stages can be provided.

[0046] Depending on how many cooling stages or coolant guide arrangements the rotor has, one of the coolant guide arrangements, for example the second, third, fourth or fifth coolant guide arrangement, forms a final cooling stage viewed in a radially outward direction. The coolant escaping from the corresponding coolant channels of this final cooling stage or coolant guide arrangement can be fed to a coolant sump after escaping during operation of the electric machine. In addition, however, it is also possible that the coolant escaping from the coolant channels of the final coolant guide arrangement or cooling stage is thrown radially outwards onto the winding overhangs of a stator of the electric machine due to centrifugal forces and can thus also cool the winding overhangs of the stator.

[0047] Each of the further coolant guide arrangements can have coolant collecting devices and coolant dispensing devices analogous to the first and / or second coolant guide arrangement, so that a coolant flows successively through the coolant channels of the coolant guide arrangements alternately from the first end side to the second end side and from the second end side to the first end side of the laminated core.

[0048] It is preferably provided that the laminated core comprises at least one second coolant guide arrangement, wherein the second coolant guide arrangement is formed as a mirror image of the first coolant guide arrangement with respect to a center plane of the laminated core running perpendicular to a rotational axis of the rotor and is arranged offset by an angle with respect to the rotational axis.

[0049] The second coolant guide arrangement is structurally identical to the first coolant guide arrangement, but is arranged in a mirror image in the laminated core of the rotor. The second coolant guide arrangement accordingly also comprises a first coolant guide arrangement and a second coolant guide arrangement at a first radius and a second radius. The first coolant guide arrangement of the second coolant guide arrangement has a plurality of first coolant channels running through the laminated core from the second end side of the laminated core to the first end side of the laminated core, and the second coolant guide arrangement of the second coolant guide arrangement has a plurality of second coolant channels running through the laminated core from the first end side of the laminated core to the second end side of the laminated core.Thus, while with respect to the first coolant guide arrangement the coolant flows in the first coolant channels of the first coolant guide arrangement from the first end side to the second end side, with respect to the second coolant guide arrangement the coolant flows in the first coolant channels of the first coolant guide arrangement from the second end side to the first end side.

[0050] It can be provided that the first radius of the first coolant guide arrangement of the first coolant guide arrangement and the first radius of the first coolant guide arrangement of the second coolant guide arrangement are identical and / or that the second radius of the second coolant guide arrangement of the first coolant guide arrangement and the second radius of the second coolant guide arrangement of the second coolant guide arrangement are identical.

[0051] In other words, the first coolant channels of the first coolant guide arrangement of the first coolant guide arrangement and the first coolant channels of the first coolant guide arrangement of the second coolant guide arrangement are located at the same distance from the axis of rotation. In this case, it is therefore provided that the first coolant guide arrangement and the second coolant guide arrangement are arranged offset from one another by an angle with respect to the axis of rotation of the rotor. In a plan view of the laminated core along the axis of rotation, the first coolant channels of the first coolant guide arrangement of the first coolant guide arrangement and the first coolant channels of the first coolant guide arrangement of the second coolant guide arrangement are thus arranged on the same radius and alternately with one another in the circumferential direction.The same applies to the coolant channels of the second, third and further coolant guide arrangements of the first and second coolant guide arrangements.

[0052] If a second coolant guide arrangement is provided, it is also provided, in particular, that the hollow rotor shaft has substantially radially aligned coolant outlet openings, which are preferably arranged in the region of the second end side of the laminated core. Furthermore, the coolant guide arrangements of the second coolant guide arrangement are configured identically to the coolant guide arrangements of the first coolant guide arrangement. This means that the coolant guide arrangements of the second coolant guide arrangement also each comprise coolant collection devices and coolant discharge devices.

[0053] It is preferably provided that the coolant collecting devices of the first coolant guide arrangement and the second coolant guide arrangement, in particular the grooves or channels, each have a partition wall that is substantially wave-shaped in a circumferential direction, wherein the partition wall separates the respective coolant collecting device from the coolant discharge devices of the respective other second coolant guide arrangement or first coolant guide arrangement.

[0054] If a first coolant guide arrangement and a second coolant guide arrangement are provided, with the respective coolant guide arrangements being arranged at the same radii, the outlet openings, for example, of the first coolant channels of the first coolant arrangement of the second coolant guide arrangement are located on the same radius as the inlet openings of the first coolant channels of the first coolant guide arrangement of the first coolant guide arrangement. Accordingly, the coolant discharge devices and the coolant collection devices of the first coolant guide arrangement and the second coolant guide arrangement are also arranged at the same radii.In order to prevent mixing of the coolant entering and exiting from the coolant channels, a partition wall is provided in each of the coolant collecting devices of the first coolant guide arrangement and the second coolant guide arrangement, which partition wall separates the respective coolant collecting device from the coolant discharge devices of the respective other second coolant guide arrangement or first coolant guide arrangement.

[0055] A further solution to the problem underlying the invention consists in an electrical machine with a stator and a rotor as described above.

[0056] It is preferably provided that the rotor is arranged in the stator in such a way that a coolant emerging from at least one coolant guide channel, in particular from a coolant dispensing device, is thrown onto a winding head of the stator during operation of the electrical machine.

[0057] A further solution to the problem underlying the invention consists in a motor vehicle comprising an electrical machine as described above.

[0058] All functions, features and configurations explained with regard to the rotor can also be transferred in an analogous manner to the electric machine or to the electric machine of the motor vehicle.

[0059] The invention is explained in more detail below with reference to the attached figures.

[0060] It shows Fig. 1 a rotor for an electrical machine, Fig. 2 an axial view of a laminated core of the rotor, Fig. 3a a development of the rotor, Fig. 3b a first detailed section of the rotor, Fig. 3c a second detailed section of the rotor, Fig. 4 a section of an electrical machine with the rotor, Fig. 5 a motor vehicle with an electric machine, and Fig. 6 a rotor for a separately excited synchronous machine.

[0061] In the figures, identical or corresponding components are marked with the same reference numerals.

[0062] Fig. 1 shows a rotor 100 for a Fig. 4 shows an electric machine 200. The rotor 100 comprises a hollow rotor shaft 10 on which a laminated core 11 is arranged. The laminated core 11 comprises a first coolant guide arrangement 12 for guiding a coolant for cooling the rotor 100 or the laminated core 11. The first coolant guide arrangement 12 comprises a first coolant guide arrangement 13 and a second coolant guide arrangement 14. The first coolant guide arrangement 13 comprises a plurality of first coolant channels 17 passing through the laminated core 11 from a first end side 15 of the laminated core 11 to a second end side 16 of the laminated core 11, wherein in the sectional view according to Fig. 1 only one of the first coolant channels 17 is shown. The second coolant guide arrangement 14 comprises a plurality of second coolant channels 18 passing through the laminated core 11 from the second end side 16 of the laminated core 11 to the first end side 15 of the laminated core 11, wherein likewise only one of the second coolant channels 18 is shown in the sectional view according to Fig. 1. The first coolant channels 17 of the first coolant guide arrangement 13 are arranged at a first radius 19 with respect to a rotational axis 20 of the rotor 100. The second coolant channels 18 of the second coolant guide arrangement 14 are arranged at a second radius 21 with respect to the rotational axis 20 of the rotor 100. The second radius 21 is larger than the first radius 19. The first coolant guide arrangement 13 can be regarded as a first cooling stage, and the second coolant guide arrangement 14 can be regarded as a second cooling stage.In addition, the first coolant guide arrangement 12 comprises a third coolant guide arrangement 22 comprising a plurality of third coolant channels 23 which run through the laminated core 11 from the first end side 15 of the laminated core 11 to the second end side 16 of the laminated core 11, and a fourth coolant guide arrangement 24 comprising a plurality of fourth coolant channels 25 which run through the laminated core 11 from the second end side 16 to the first end side 15. The third coolant channels 23 are located on a third radius 26, and the fourth coolant channels 25 are arranged at a fourth radius 27, wherein the third radius 26 is greater than the second radius 21 and the fourth radius 27 is greater than the third radius 26.

[0063] A first coolant collecting device 28 of the first coolant guide arrangement 13 is arranged on the first end side 15. The first coolant collecting device 28 is arranged and designed such that, during operation of an electric machine 200 equipped with the rotor 100, coolant escaping from radial coolant outlet openings 29 of the hollow rotor shaft 10 is collected by the latter and introduced into the first coolant channels 17. The second coolant guide arrangement 14 comprises a second coolant collecting device 30 arranged on the second end side 16, which is designed and arranged to collect coolant escaping from the first coolant channels 17 of the first coolant guide arrangement 13 at the second end side 16 and to introduce it into the second coolant channels 18 of the second coolant guide arrangement 14.Accordingly, the third coolant guide arrangement 22 and the fourth coolant guide arrangement 24 also have coolant collecting devices. The first coolant collecting device 28 of the first coolant guide arrangement 13 is arranged at inlet openings 31 of the first coolant channels 17. The second coolant collecting device 30 of the second coolant guide arrangement 14 is arranged at inlet openings 32 of the second coolant channels 18 of the second coolant guide arrangement 14.

[0064] Furthermore, the first coolant guide arrangement 13 has a coolant discharge device 33, which is arranged on the second end side 16. The first coolant discharge device 33 is designed to deflect coolant emerging from outlet openings 34 of the first coolant channels 17 on the second end side 16 radially outward by 90°. Likewise, the second coolant guide arrangement 14 comprises a second coolant discharge device 35, which is arranged at outlet openings 36 of the second coolant channels 18 on the first end side 15 of the laminated core 11. The second coolant discharge device 35 is designed to deflect coolant emerging from the outlet openings 36 of the second coolant channels 18 radially outward by 90°. The same applies to the third coolant guide arrangement 22 and the fourth coolant guide arrangement 24.

[0065] During operation of an electric machine 200 equipped with the rotor 100, a coolant introduced into the hollow rotor shaft 10 is propelled outwardly from the substantially radially aligned coolant outlet openings 29 due to the centrifugal forces that occur. The outwardly propelled coolant is collected by the first coolant collection device 28 of the first coolant guide arrangement 13, introduced into the first coolant channels 17, and flows through the laminated core 11 of the rotor 100 from the first end side 15 to the second end side 16. At the second end side 16, the coolant exits the first coolant guide channels 17, is deflected radially outward by 90° by the first coolant discharge device 33, and is propelled outwardly due to the acting centrifugal forces.The coolant is then collected by the second coolant collection device 30 of the second coolant guide arrangement 14 and introduced into the second coolant channels 18 of the second coolant guide arrangement 14. The coolant then flows through the laminated core from the second end 16 to the first end 15 and exits from the outlet openings 36 of the second coolant channels 18. It is deflected outward by 90° by the second coolant discharge device 35 of the second coolant guide arrangement 14 and is propelled outward due to the centrifugal forces acting thereon. In the same way, the coolant then passes through the coolant channels of the third coolant guide arrangement 22 and the fourth coolant guide arrangement 24. The coolant thus passes through the laminated core 11 several times and can consequently effectively absorb heat from the laminated core 11.

[0066] The laminated core 11 further comprises a second coolant guide arrangement 37. The second coolant guide arrangement 37 is mirror-inverted to the first coolant guide arrangement 12 with respect to a center plane 38 of the laminated core 11 extending perpendicular to the rotational axis 20 of the rotor 100. Accordingly, the second coolant guide arrangement 37 also comprises a first coolant guide arrangement 39 with a plurality of first coolant channels 40, a second coolant guide arrangement 41 with a plurality of second coolant channels 42, as well as a third coolant guide arrangement 43 and a fourth coolant guide arrangement 44. Furthermore, the operation of the second coolant guide arrangement 37 is identical to that of the first coolant guide arrangement 12.

[0067] Fig. 2 shows a plan view of the first end side 15 of the laminated core 11 along the rotational axis 20 of the rotor 100. Since the coolant channels 17, 18, 40, 42 of the first coolant guide arrangement 12 and the second coolant guide arrangement 37 are each located on the same radii, the first coolant guide arrangement 12 and the second coolant guide arrangement 37 are offset from one another by an angle 45 with respect to the rotational axis 20. Viewed in a circumferential direction 46, the coolant channels 17, 18 of the first coolant guide arrangement 12 alternate with the coolant channels 40, 42 of the second coolant guide arrangement 37.

[0068] Fig. 3a shows a development over the circumference of the rotor 100 according to Fig. 1 at the first radius 19, on which the first coolant channels 17 of the first coolant guide arrangement 13 of the first coolant guide arrangement 12 and the first coolant channels 40 of the first coolant guide arrangement 39 of the second coolant guide arrangement 37 are arranged. Fig. Figure 3b shows a sectional view along AA. Fig. 3c shows a sectional view along BB.

[0069] The first coolant collecting device 28 of the first coolant guide arrangement 13 of the first coolant guide arrangement 12 is designed in the form of a groove 47 surrounding the rotor 100 on the end side 15. Analogously, the first coolant collecting device 48 of the first coolant guide arrangement 39 of the second coolant guide arrangement 37 is also designed as a groove 47 surrounding the rotor 100 on the second end side 16. Guide devices 49, in particular guide vanes 50, can be arranged in the grooves 47. The first coolant discharge device 33 of the first coolant guide arrangement 13 of the first coolant guide arrangement 12 and the first coolant discharge device 51 of the first coolant guide arrangement 39 of the second coolant guide arrangement 37 comprise tubes or pipes 53 formed in material formations 52 and angled by 90°, as shown in Fig. 3c in cross-sectional view. Substantially wave-shaped partition walls 54 are provided between the first coolant collection device 28 of the first coolant guide arrangement 13 of the first coolant guide arrangement 12 and the first coolant discharge device 51 of the first coolant guide arrangement 39 of the second coolant guide arrangement 37, or between the first coolant collection device 48 of the first coolant guide arrangement 39 of the second coolant guide arrangement 37 and the first coolant discharge device 33 of the first coolant guide arrangement 13 of the first coolant guide arrangement 12, to separate the coolant flows.

[0070] Fig. 4 shows a section of an electrical machine 200 with a rotor 100 according to the Fig. 1 to 3c. In addition to the rotor 100, the electric machine 200 has a stator 55 with winding heads 56. Coolant end collecting devices 57 are arranged on the radially outer region of the laminated core 11. These devices collect the cooling fluid escaping from the fourth coolant guide assemblies 24, 44 of the first and second coolant guide assemblies 12, 37. The coolant end collecting devices 57 have discharge openings 58 through which, during operation of the electric machine 200, the coolant can escape due to the centrifugal forces acting on it and be thrown onto the winding heads 56. This also allows the winding heads 56 to be cooled.

[0071] Fig. 5 shows a motor vehicle 300 with an electric machine 200 according to Fig. 4.

[0072] Fig. 6 shows another rotor 100. The rotor 100 of the Fig.6 is designed for a separately excited synchronous machine and comprises excitation windings 59 which project beyond the end sides 15, 16 of the laminated core 11.

[0073] The laminated core 11 has a first coolant guide arrangement 12 with a first coolant conducting arrangement 13 and a second coolant conducting arrangement 14, wherein the first coolant conducting arrangement 13 comprises a plurality of first coolant channels 17 running through the laminated core 11 from the first end side 15 of the laminated core 11 to the second end side 16 of the laminated core 11. The second coolant conducting arrangement 14 comprises a plurality of second coolant channels 18 running through the laminated core 11 from the second end side 16 of the laminated core 11 to the first end side 15 of the laminated core 11. A first coolant collecting device 28 of the first coolant conducting arrangement 13 is arranged on the first end side 15.The first coolant collecting device 28 is arranged and designed such that, during operation of an electric machine equipped with the rotor 100, coolant escaping from radial coolant outlet openings 29 of the hollow rotor shaft 10 is collected by the latter and introduced into the first coolant channels 17. The second coolant guide arrangement 14 comprises a second coolant collecting device 30 arranged on the second end side 16, which is designed and arranged to collect coolant escaping from the first coolant channels 17 of the first coolant guide arrangement 13 at the second end side 16 and to introduce it into the second coolant channels 18 of the second coolant guide arrangement 14. Furthermore, the first coolant guide arrangement 13 has a coolant discharge device 33 arranged on the second end side 16.The first coolant discharge device 33 is designed to deflect a coolant exiting the first coolant channels 17 at the second end 16 radially outward by 90°. Likewise, the second coolant guide arrangement 14 comprises a second coolant discharge device 35, which is arranged on the first end 15 of the laminated core 11. The second coolant discharge device 35 is designed to deflect a coolant exiting the second coolant channels 18 radially outward by 90°.

[0074] The first coolant discharge device 33 of the first coolant guide arrangement 13 and the second coolant discharge device 35 of the second coolant guide arrangement are designed as tubes or pipes 53 angled by 90°, which extend in a balancing disk 62. Each of the tubes or pipes 53 comprises a first, substantially axially aligned, first tube or pipe section 60 and a second, substantially radially outwardly aligned, first tube or pipe section 61, which is angled in particular by 90° to the first tube or pipe section 60. The second tube or pipe section 61 of the first coolant discharge device 33 opens into the second coolant collection device 30 of the second coolant guide arrangement 14. As a result, the transfer of the coolant from the first coolant discharge device 33 to the second coolant collection device 30 is not impeded by the excitation windings 59.Axial pressure equalization channels 63 are also provided for atmospheric pressure equalization. List of reference symbols 100 rotors 200 Electric Machine 300 motor vehicles 10 Rotor shaft 11 sheet package 12 First coolant guide arrangement 13 First coolant guide arrangement 14 Second coolant guide arrangement 15 First end page 16 Second end page 17 First coolant channel 18 Second coolant channel 19 First radius 20 Rotation axis 21 Second radius 22 Third coolant guide arrangement 23 Third coolant channel 24 Fourth coolant guide arrangement 25 Fourth coolant channel 26 Third radius 27 Fourth radius 28 First coolant collecting device 29 Coolant outlet opening 30 Second coolant collecting device 31 Inlet opening 32 Inlet opening 33 First coolant dispensing device 34 Outlet opening 35 Second coolant dispenser 36 Outlet opening 37 Second coolant guide arrangement 38 Middle Level 39 First coolant guide arrangement 40 First coolant channel 41 Second coolant guide arrangement 42 Second coolant channel 43 Third coolant guide arrangement 44 Fourth coolant guide arrangement 45 angle 46 Circumferential direction 47 gutter 48 First coolant collecting device 49 Guidance device 50 guide vanes 51 First coolant dispensing device 52 Material forming 53 tubes 54 Partition wall 55 Stator 56 winding head 57 Coolant end collection device 58 Discharge opening 59 Excitation winding 60 First tube section 61 Second tube section 62 balancing disc 63 Pressure equalization channel QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 204 671 A1

[0005] JP 2019-187063 A

[0006] DE 10 2019 217 510 A

[0007] DE 10 2019 124 209

[0008]

Claims

[1] Rotor (100) for an electrical machine (200) comprising a hollow rotor shaft (10) and a laminated core (11) arranged on the rotor shaft (10), wherein the laminated core (11) comprises at least one first coolant guide arrangement (12), wherein the first coolant guide arrangement (12) comprises at least one first coolant guide arrangement (13) and a second coolant guide arrangement (14), wherein the first coolant guide arrangement (13) has a plurality of first coolant channels (17) passing through the laminated core (11) from a first end side (15) of the laminated core (11) to a second end side (16) of the laminated core (11) at a first radius (19), and wherein the second coolant guide arrangement (14) has a plurality of second coolant channels (18) passing through the laminated core (11) from the second end side (16) of the laminated core (11) to the first end side (15) of the laminated core (11) at a second radius (21), characterized byin that the first coolant guide arrangement (13) comprises a first coolant collecting device (28) arranged on the first end side (15) at the first radius (19), wherein the first coolant collecting device (28) is arranged and designed such that a coolant collected by the first coolant collecting device (28) can flow into the first coolant channels (17), and in that the second coolant guide arrangement (14) comprises a second coolant collecting device (30) arranged on the second end side (16) at the second radius (21), wherein the second coolant collecting device (30) is arranged and designed such that a coolant collected by the second coolant collecting device (30) can flow into the second coolant channels (18). [2] Rotor (100) according to claim 1, characterized bythat the second radius (21) is greater than the first radius (19), and / or that the hollow rotor shaft (10) has substantially radially aligned coolant outlet openings (29), and that the first coolant collecting device (28) of the first coolant guide arrangement (13) is arranged and designed to collect a coolant emerging from the coolant outlet openings (29) of the rotor shaft (10), and / or that the second coolant collecting device (30) is arranged and designed to collect a coolant emerging from the first coolant channels (17) of the first coolant guide arrangement (13) at the second end side (16). [3] Rotor (100) according to claim 1 or 2, characterized bythat the first coolant guide arrangement (13) has a first coolant discharge device (33) arranged on the second end side (16) at the first radius (19), which is designed to deflect a coolant emerging from the first coolant channels (17) radially outwards, and that the second coolant guide arrangement (14) has a second coolant discharge device (35) arranged on the first end side (15) at the second radius (21), which is designed to deflect a coolant emerging from the second coolant channels (18) radially outwards. [4] Rotor (100) according to claim 3, characterized by that the first coolant discharge device (33) and the second coolant collection device (30) are arranged relative to one another in such a way that a coolant deflected radially outwards by the first coolant discharge device (33) is collected by the second coolant collection device (30). [5] Rotor (100) according to one of the preceding claims, characterized by that the first coolant collecting device (28) and / or the second coolant collecting device (30) is designed as a groove or channel (47) running in a circumferential direction (46) of the laminated core (11) and open radially inwards, and / or that the first coolant collecting device (28) and / or the second coolant collecting device (30), in particular the groove or channel (47), has guide devices (49), in particular guide vanes (50). [6] Rotor (100) according to one of claims 3 to 5, characterized byin that the first coolant dispensing device (33) and / or the second coolant dispensing device (35) comprises radially outwardly directed, preferably angled, tubes or pipes (53), wherein a respective tube or pipe (53) of the first coolant dispensing device (33) is fluidically connected to one of the first coolant channels (17), and wherein a respective tube or pipe (53) of the second coolant dispensing device (35) is fluidically connected to one of the second coolant channels (18). [7] Rotor (100) according to one of the preceding claims, characterized byin that the laminated core (11) comprises at least one second coolant guide arrangement (37), wherein the second coolant guide arrangement (37) is formed as a mirror image of the first coolant guide arrangement (12) with respect to a center plane (38) of the laminated core (11) running perpendicular to a rotational axis (20) of the rotor (100) and is arranged offset by an angle (45) with respect to the rotational axis (20). [8] Rotor (100) according to claim 7, characterized byin that the coolant collecting devices (28, 30, 48) of the first coolant guide arrangement (12) and the second coolant guide arrangement (37), in particular the grooves or channels (47), each have a partition wall (54) which is substantially wave-shaped in a circumferential direction (46), wherein the partition wall (54) separates the respective coolant collecting device (28, 30, 48) from the coolant discharge devices (33, 35, 51) of the respective other second coolant guide arrangement (37) or first coolant guide arrangement (12). [9] Electrical machine (200) with a stator (55) and a rotor (100) according to one of the preceding claims. [10] Motor vehicle (300) comprising an electric machine (200) according to claim 9.

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