Rotor assembly with coolant guide

Abstract

The invention relates to a rotor assembly with coolant guide and one axis of rotation for a motor vehicle, comprising at least the following components: - a sheet metal package containing multiple diaper bags and pole shoes; - one star disk at each axial end of the sheet metal stack; - at least one end plate adjacent to the respective star plate at an axial end of the sheet metal stack; - secondary insulation in the diaper bags; - forming a rotor winding, a corresponding number of rotor coils in the winding pockets; and - Each rotor assembly comprises a displacer body positioned between adjacent rotor coils in a respective winding pocket, with at least one of the displacer bodies including a coolant line for conveying a coolant. The rotor assembly is characterized primarily by the fact that at least one of the displacer bodies is formed by plastic casting. With the rotor assembly proposed here and the corresponding manufacturing process, an electric traction machine for high-performance applications can be manufactured cost-effectively in series production.

Description

[0001] The invention relates to a rotor assembly with coolant guide, as well as a manufacturing method with such a rotor assembly for a rotor assembly.

[0002] With the advancing electrification of motor vehicles, increasingly powerful and cost-effective electric traction motors are in demand on the market. Conventional electric traction motors usually feature indirect cooling. This means that the stator is usually cooled from the side facing away from the machine. Most of the waste heat within an electric traction motor is generated in the stator winding and, in the case of a separately excited synchronous motor (FSM), also in the rotor winding. Solutions are now known for the rotor or rotor assembly in which a cooling medium is passed centrally through the rotor shaft. However, the distance between the loss source and the cooling system, and thus the thermal resistance, is still very large. The lost energy converted in the rotor can therefore only be absorbed to a limited extent by the thermal mass of the rotor and then only slowly dissipated.

[0003] A more efficient approach is to place a cooling line in the area of ​​the rotor winding. This shortens the heat path and improves the thermal connection of the rotor's critical components. However, implementing such a cooling technology economically is challenging.

[0004] Based on this, the present invention is based on the object of at least partially overcoming the disadvantages known from the prior art. The features of the invention are derived from the independent claims, for which advantageous embodiments are presented in the dependent claims. The features of the claims can be combined in any technically reasonable manner, whereby the explanations from the following description as well as features from the figures, which comprise additional embodiments of the invention, can also be consulted for this purpose.

[0005] The invention relates to a rotor assembly with coolant guide and a rotation axis for a motor vehicle, comprising at least the following components: - a laminated core with a plurality of winding pockets and pole pieces; - one star disk at each axial end of the laminated core; - at least one cover plate adjacent to the respective star plate at one axial end of the laminated core; - secondary insulation in the diaper bags; - a rotor winding forming a corresponding number of rotor coils in the winding pockets; and - one displacer body each between adjacent rotor coils in a respective winding pocket, wherein at least one of the displacer bodies comprises a coolant line for conducting a coolant.

[0006] The rotor assembly is primarily characterized in that at least one of the displacer bodies is formed by plastic molding.

[0007] In the following, reference is made to the specified axis of rotation whenever, without explicit indication to the contrary, the axial direction, radial direction, or the direction of rotation and corresponding terms are used. Ordinal numbers used in the preceding and following descriptions serve only to clearly distinguish them and do not reflect the order or ranking of the designated components. An ordinal number greater than one does not necessarily imply that another such component must be present.

[0008] Here, a rotor assembly is proposed which enables efficient dissipation of waste heat from the rotor winding. In this case, a laminated core of the rotor assembly, for example, a large number of individual ferromagnetic sheets (for example produced by stamping), which are magnetically insulated from one another, are joined together to form a stack or package of sheets. A so-called baked enamel is used for this purpose. The laminated core has a plurality of winding pockets and pole shoes arranged between them. The rotor winding is formed from a number of rotor coils corresponding to the number of pole shoes (and winding pockets). This is carried out conventionally, for example, preferably by so-called needle winding or flyer winding.For one rotor assembly design, especially for a so-called separately excited synchronous machine (SSM), a displacer is provided to prevent the rotor winding from slipping or breaking under the high speed-related and / or torque-induced loads. Such a displacer is known for its function and is necessary for a SSM.

[0009] The rotor winding is made up of one or more electrically insulated (copper) wires. In the following, we will refer to wires in the plural because the sections overlap multiple times, even when wound as a single piece, giving the appearance of multiple wires. From an electrical engineering perspective, it is usually a single wire, i.e. a single electrical conductor. However, an approval requirement requires that an additional layer of electrical insulation, known as secondary insulation, be provided between the rotor coil and the laminated core. For example, a layer of slotted base paper is used in the winding pockets for this purpose; however, the insulation layer can also be applied using a transfer molding process. In addition to the electrical insulation, the secondary insulation is preferably also thermally conductive.

[0010] The two star disks at the axial ends of the laminated core are primarily intended to impose a defined radius on the wires when turning into the opposite winding pocket around the pole piece, or at least to limit this radius to a defined minimum radius, and to prevent kinks or breakage. Such a star disk is preferably made of an electrically insulating material.

[0011] The cover plate is axially and rotationally fixed to the rotor shaft. In one embodiment, the cover plate serves as a balancing plate, intended solely for (dynamic) balancing of the rotor assembly. Alternatively or additionally, the cover plate is designed to axially secure the laminated core and the rotor winding.

[0012] The idea here is to facilitate the dissipation of waste heat from the rotor winding by having the displacer body incorporate one or more coolant lines. This minimizes the distance between the current-carrying wires in the winding pocket and the coolant line. The improved heat transfer into the cooling medium is further enhanced by reducing the heat-insulating air gap, thus creating a direct and individually molded fit for the displacer body. During plastic molding, the rotor coils themselves form the (lost) mold for the displacer body to be formed. Using a negative mold with at least one coolant line, coolant can flow through in close proximity with low thermal conduction resistance. Due to the high demands placed on the plastic, transfer molding is preferred.In one embodiment, the plastic used is provided with additives that improve its thermal conductivity, for example ceramic particles.

[0013] In one embodiment, the stability or strength and contact surface of the displacer formed by plastic molding on the pole pieces are sufficient for the operating conditions (maximum speed and / or torque surges) to hold the displacer in the desired position over the desired service life. Alternatively, or as a precaution, a cover slide is used, for example, made of a fiber-reinforced plastic, which forms a contact surface for the displacer on the radially outer side (as seen from the displacer) in radially inner contact with the pole pieces.

[0014] It should be noted that in an advantageous embodiment, all displacement bodies are formed identically, or at least all displacement bodies or a majority of the displacement bodies comprise at least one coolant line. In one embodiment, a coolant line is formed that mechanically weakens the displacement body as little as possible while simultaneously enabling a high volume flow for a coolant. For example, such a coolant line is dumbbell-shaped in cross-section (at least in one section), i.e., with two flared ends and a narrower connecting channel, while simultaneously achieving a large surface area effective for the transfer of thermal energy.

[0015] It is further proposed in an advantageous embodiment of the rotor assembly that at least one of the secondary insulations and / or the star disk of the rotor are formed by means of injection molding, are preferably produced in one piece.

[0016] Here, injection molding is proposed as a manufacturing process for the secondary insulation and / or the star disk, preferably as a one-piece construction or cast in a single batch. This has the advantage of achieving a secure connection to the laminated core, a low wall thickness, an electrically insulating material, and (under certain circumstances) a process identical to that used for forming the displacer.

[0017] It is further proposed in an advantageous embodiment of the rotor assembly that, during plastic casting, the at least one respective displacement body is formed integrally with an end plate (for example, balancing disc), wherein the end plate is formed axially adjacent to the respective star disc, wherein a defined round outer surface is preferably formed radially outward.

[0018] The end plate, which preferably also or exclusively serves as a balancing disk, is formed in one embodiment such that the end portions of the rotor winding, i.e., where the wires are wrapped over the respective star disk, are completely covered. This securely encloses the winding heads at the ends. In one embodiment, the end plate comprises a section of the respective coolant line(s). In one embodiment, a uniform outer surface, for example, rotationally symmetrical and / or with a defined roundness, is formed radially on the outside (for example, for good balancing).

[0019] It is further proposed in an advantageous embodiment of the rotor assembly that a reinforcement ring is clamped around the displacer bodies adjacent to the laminated core, wherein the reinforcement ring is preferably clamped exclusively around the defined round outer surface of an end plate according to an embodiment according to the above description.

[0020] The reinforcement ring is a component of the rotor assembly by means of which mechanical reinforcement against the applied loads can be achieved. For example, such a reinforcement ring is made of metal or of a tensile-resistant plastic, preferably with a circumferential fabric or scrim as a reinforcing insert in the plastic. For example, such a reinforcement ring is thermally shrunk on. In an advantageous embodiment, the reinforcement ring is clamped exclusively around the defined, round outer surface of the end plate described above. This ensures that no jump in diameter and / or stiffness (due to different clamped materials) occurs in the clamped section. The reinforcement ring is thus securely clamped around the respective outer surface over its desired service life, and a uniform force transmission between the reinforcement ring and the respective outer surface is achieved.

[0021] It should be noted that in conventional rotor assemblies, instead of a reinforcement ring, a reinforcement cap with a flange portion with a large-area radial extension is used. The reinforcement ring preferably has a purely axial extension, alternatively at least one stiffening element with a radial extension, wherein the radial extension is significantly smaller than the axial extension, preferably less than twice or even less than the wall thickness of the main extension section. In a preferred embodiment, the reinforcement ring does not have an element with a radially inward extension.

[0022] It is further proposed in an advantageous embodiment of the rotor assembly that a radial distributor is formed from the cover plate for a coolant to the at least one coolant line in the respective displacement body, wherein an axially compressed sealing system is preferably arranged between the cover plate and the displacement bodies.

[0023] In this embodiment, an axial gap is formed between the cover plate and the rest of the rotor assembly, which is configured to conduct a coolant with a suitably low flow resistance into the respective coolant line(s) of the displacement body(s). In one embodiment, a circular gap is formed. In one embodiment, a star-shaped channel system is formed.

[0024] In an advantageous embodiment, a sealing system is formed by a circumferential sealing ring being axially and / or radially compressed between the cover plate and the displacement body(s), preferably the end plate as described above. The sealing ring is preferably a simple static seal, for example, in the manner of an O-ring.

[0025] It is further proposed in an advantageous embodiment of the rotor assembly that the at least one coolant line is arranged on the outlet side, the guided coolant: - to be thrown radially outwards; - to the radial center, preferably via at least one return line; and / or - into a cooling circuit, preferably via a collecting device.

[0026] Because the coolant, especially in a liquid form, is conducted through a rotating assembly and no rotating parts are to be tempered during most of the operation, a transition is necessary for the return to a cooling circuit. In one embodiment, the coolant is centrifuged radially outside the rotor shaft through radially outwardly open or axially aligned openings. This has the advantage of a suction effect. Furthermore, the centrifuged coolant can be used to cool the winding head(s) of a stator winding by centrifuging the coolant onto this winding head.

[0027] A return to the radial center allows for a dry design of the machine, but then the fluid friction in the cooling system must be overcome without the aforementioned suction effect. This return must therefore be implemented actively.

[0028] A collection device is possible for both variants. It allows for the low-energy collection of the coolant that is thrown onto non-rotating components and then flows off (primarily due to gravity). With active recirculation, the pressure can be returned to the remaining operating pressure in the cooling circuit, for example, initially to atmospheric pressure. In addition to these aspects, an advantageous embodiment provides for filtration so that any particles that may be collected are separated in the area of ​​the rotor assembly and are not passed into the rest of the cooling circuit or through the rotor assembly again.

[0029] According to a further aspect, an electric drive machine for a motor vehicle is proposed, comprising an electric traction machine with at least the following components: - a rotor assembly according to an embodiment as described above; - a stator with a stator winding, preferably a hairpin winding; - a rotor shaft to which the rotor assembly is torque-fixed; and - a coolant connection for connecting the at least one coolant line of the rotor assembly, and preferably a coolant guide of the stator, to a cooling circuit.

[0030] The motor vehicle is intended for transporting at least one passenger and / or transported goods and for this purpose has a passenger cell and / or a cargo cell. The motor vehicle is driven via at least one drive wheel by means of the torque of at least one of the electric traction machines. This electric traction machine comprises a rotor or a rotor assembly, as described above, on a rotor shaft and a stator, which are equipped with a correspondingly controlled electrical voltage supply or power supply for outputting a torque to the rotor shaft. For example, the electric traction machine is configured as a FSM. For example, the electric traction machine is used on a second (additional) drive axle of the motor vehicle, while another (electric and / or combustion engine) traction machine is used as the main drive for the motor vehicle.Alternatively or additionally, the electric traction machine described herein (equipped with the rotor assembly as described herein) is configured as the main drive, wherein the cooling of the rotor assembly is designed for high-load continuous operation. The cooling circuit, via which the rotor assembly (and preferably also the stator or its stator winding) is connected for cooling, is preferably configured for cooling or temperature control of a large number of other units in the motor vehicle, such as the pulse-controlled inverter, the high-voltage battery, the on-board charger, the DC-DC converter, but also the passenger compartment and other comfort-related or payload-related areas. It should be noted that the coolant in the rotor assembly can be used to warm up the rotor assembly under certain circumstances (for example, extreme cold in winter).

[0031] According to a further aspect, a manufacturing method for a rotor assembly according to an embodiment as described above is proposed, comprising at least the following steps in the order mentioned: a. Providing the laminated core, preferably on a rotor shaft, b. Insertion of the secondary insulation and a star washer at each axial end of the laminated core; c. Forming the rotor winding; d. Inserting a negative lead into the respective diaper bag; e. Forming the at least one displacement body with coolant line, and preferably the end plate, by means of transfer molding between the line negative and the laminated core; and f. Applying at least one cover plate adjacent to the respective star plate at one axial end of the laminated core.

[0032] In this method, the steps mentioned above are proposed for manufacturing a rotor assembly. These allow for an efficient process, especially when integrated into a production line with upstream and / or downstream steps. For an explanation of the steps, reference is made, at least in addition or alternatively, to the preceding and following descriptions of the rotor assembly.

[0033] In an advantageous embodiment of the manufacturing method, it is further proposed that b1. inserting an insulation negative into the respective changing pockets; b2. Forming the respective secondary insulation, and preferably the star disk, by means of plastic casting between the insulation negative and the laminated core; and b3. Removing the isolation negative.

[0034] In a particularly preferred embodiment, the secondary insulation and / or the star disk, preferably both in a single process, are produced by injection molding. A single injection molding process occurs between the (liquid) injection of the plastic and the curing and removal of the negative mold. Forming the secondary insulation and the star disk in a single process thus reduces both the equipment and time required.

[0035] It is further proposed in an advantageous embodiment of the manufacturing method that in a further step, for example, a reinforcement ring according to an embodiment as described above is clamped around the displacement bodies, preferably exclusively around the defined round outer surface of an end plate according to an embodiment as described above, preferably by means of thermal shrinking.

[0036] The step proposed here increases the safety and / or the maximum permissible speed of the rotor assembly. During thermal shrink-fitting, the rotor assembly is preferably not heated below room temperature, but rather only the reinforcement ring is heated. Alternatively, or additionally, only the defined, round outer surface is cooled below room temperature.

[0037] It is further proposed in an advantageous embodiment of the manufacturing method that in step f. the cover plate is formed according to an embodiment according to the above description, preferably following a step z. according to an embodiment according to the above description, and the cover plate is pressed axially against the displacement bodies, or preferably against the respective end plate according to an embodiment according to the above description, to form its sealing system, preferably by thermal shrinking onto a rotor shaft belonging to the rotor assembly.

[0038] It should be noted that step z. can be performed both before and after step f. When thermally shrinking the cover plate, it is preferable not to heat the rotor assembly or the rotor shaft below room temperature, but rather to heat only the cover plate.

[0039] The invention described above will be explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way limited by the purely schematic drawings, whereby it should be noted that the drawings are not to scale and are not suitable for defining proportions. It is shown in Fig. 1 a rotor assembly within a stator in a cross-section; Fig. 2 Flowchart of a manufacturing process for a rotor assembly; Fig. 3 a laminated core with secondary insulation for a rotor assembly in a cross-section; Fig. 4 the laminated core with secondary insulation and star washer according to Fig. 3 for a rotor assembly in an axial quarter section; Fig. 5 a laminated core with secondary insulation and rotor winding for a rotor assembly in a cross-section; Fig. 6 a laminated core with star disk and rotor winding for a rotor assembly according to Fig. 5 in an axial quarter section; Fig. 7 a laminated core with secondary insulation, rotor winding and displacer with cooling channels for a rotor assembly in a cross-section; Fig. 8 a laminated core with secondary insulation, rotor winding and displacer with at least one cooling channel for a rotor assembly according to Fig. 6 in an axial quarter section (rotor winding not visible in sectional view); Fig. 9 a laminated core with secondary insulation, rotor winding and displacer with at least one cooling channel and reinforcement ring for a rotor assembly according to Fig. 8 in an axial quarter section (rotor winding not visible in sectional view); Fig. 10 a rotor assembly according to Fig. 9 in an axial quarter section with mounted balancing disc and inserted sealing element; Fig. 11 a cooling circuit with coolant lines within the rotor assembly of an electric traction machine; and Fig. 12 a motor vehicle with electric traction machines.

[0040] In Fig. 1 shows a rotor assembly 1 within a stator 27 in a cross-section in a schematic representation. For better clarity, here and in the following, identical components are each provided with only one reference numeral. In this exemplary embodiment, a rotor shaft 24 is arranged so as to be centrally rotatable about a rotation axis 2 and is connected to the laminated core 4 in a torque-resistant manner (for example by pressing or shrinking). The laminated core 4 forms both the majority of the pole shoes 6 (here six) and the corresponding number of winding pockets 5. The rotor winding 11 is wound around the pole shoes 6, with a rotor coil 12 being wound around each pole shoe 6, which together form the rotor winding 11. Thus, approximately half the wires of two rotor coils 12 are arranged in each winding pocket 5.To prevent the rotor winding 11 from slipping in the winding pockets 5, a displacer body 13 is arranged in each case. Here, these displacer bodies 13 are designed with coolant lines 14. The coolant lines 14 have (here purely optionally all) a dumbbell-shaped cross-section. In the sectional plane shown, or as a purely functional representation, the coolant lines 14 are brought together in the center 20, namely in the rotor shaft 24, via connecting lines 31 in a supply line 32. These connecting lines 31 are preferably connected by means of the end plate 9 (for example a balancing plate, not visible here, compare . Fig. 10). In one embodiment, this (star-shaped) arrangement of the connection of the coolant line 14 is arranged exclusively at an inlet-side end 8 of the rotor assembly 1 according to the flow direction of the coolant.

[0041] The rotor assembly 1 is arranged within the stator 27 with the stator winding 30 and is configured for rotation about the rotation axis 2. Together with the stator 27 and corresponding power electronics, the rotor assembly 1 forms an electric traction machine 39 (or a traction drive).

[0042] In Fig. 2 shows a flow chart of a manufacturing process for a rotor assembly 1. Here, the final result is compared to the Fig. 1 and / or on the Fig. 7 to Fig. 11, and especially for the individual steps, for example, on the Fig. 3 to Fig. 10. Reference is made to the respective description for any additional details.

[0043] In step a., a laminated core 4 is provided, for example similar to that shown schematically in Fig. 4 (but still without secondary insulation 10).

[0044] In step b. (purely optional with the sub-steps b1. to b3.) the secondary insulation 10 and the two star disks 7 are inserted at the axial ends 8 (compare Fig. 4 and Fig. 3). The secondary insulation 10 is an approval requirement to ensure electrical insulation between a rotor coil 12 and the laminated core 4 while maintaining the prescribed and necessary clearances and creepage distances.

[0045] In sub-step b1, a (possibly multi-part) insulation negative 26 and, if applicable, further molded parts are introduced into the laminated core 4 for the secondary insulation 10. The insulation negative 26 is required for plastic molding, preferably injection molding, of the plastic to form the secondary insulation 10 (and preferably also the star disks 7), so that in the subsequent sub-step b2, the secondary insulation 10 is introduced with a predefined thickness into the winding pockets 5 of the laminated core 4 using the introduced plastic. In the final sub-step b3 of step b, the insulation negative 26 and any further molded parts inserted are removed from the rotor assembly 1.

[0046] In step c., the rotor winding 11 is formed, i.e. (for example, a copper wire) is wound into the winding pockets 5 or around the pole shoes 6. This is shown schematically in Fig. 6 and Fig. 5. The rotor winding 11 is inserted, for example, using a conventional needle winding process. The rotor winding 11 then forms the rotor coil 12 of the rotor assembly 1. The winding pockets 5 are irregularly occupied due to the rotor winding 11 and / or differently depending on the respective desired winding result (for example, depending on the desired motor power). A displacement body 13 is required to fix the rotor winding 11 in its position and to protect it against displacement due to mechanical loads (high speed, torque shocks, or vibrations) encountered during operation.

[0047] In a subsequent step d., a line negative 25 is inserted into the respective winding pockets 5, so that in the subsequent step e., the coolant line 14 is formed in a displacement body 13. This is shown schematically in Fig. 8 and Fig. 7. In step e., the rotor winding 11 is enclosed by the introduced plastic by means of plastic molding, preferably injection molding, in such a way that the plastic rests almost seamlessly against the rotor winding 11. This forms a displacer body 13 which comprises a coolant line 14 and at the same time forms a very good thermal connection between the wire of the rotor winding 11 and the respective coolant line 14 in the displacer body 13. In this embodiment, therefore (apart from technically induced tolerances), no or a negligible air gap is provided between the rotor winding 11 and the displacer body 13. In an advantageous embodiment, in the same process by means of plastic molding in step e., the end plates 15 are formed at the axial ends 8 of the rotor assembly 1 at the same time.Alternatively, the end plates 15 or one of the end plates 15 are manufactured in a separate step or subsequent to the formation of the displacer body 13. The displacer body 13 can also be inserted axially into the winding pockets 5 as a component manufactured outside the rotor assembly 1. In doing so, it compresses the winding and thus ensures its stability during machine operation. The end plates 15 have a defined, round outer surface 16. Preferably, the end plate 15 completely encloses or conceals the star disk 7 (and, if applicable, the secondary insulation 10 protruding axially from the winding pockets 5) at the end of the laminated core 4.

[0048] In step z., in the embodiment shown here, purely optionally before step f., a reinforcement ring 17 surrounds the defined, round outer surface 16 of the end plate 15. The reinforcement ring 17 increases the safety and / or the maximum permissible speed of the rotor assembly 1. For example, the reinforcement ring 17 is applied by thermal shrinking. During thermal shrinking, the rotor assembly 1 is preferably not kept below room temperature; instead, only the reinforcement ring 17 is heated.

[0049] In step f (which is purely optional here), at least one cover plate 9 (for example a balancing plate) is applied adjacent to the respective star plate 7 at an axial end 8 of the laminated core 4. In this embodiment (see Fig. 10), an axial gap is formed between the cover plate 9 and the rest of the rotor assembly 1, which is configured to conduct the coolant with a suitably low flow resistance into the respective coolant line 14 of the displacement body(s) 13. In addition, a sealing system 19 is formed by a circumferential sealing ring 29 being axially and / or radially compressed between the cover plate 9 and the end plate 15. For example, the sealing ring 29 is a simple static seal in the manner of an O-ring.

[0050] In Fig. 3 shows a schematic cross-section of a laminated core 4 with secondary insulation 10 for a rotor assembly 1, for example in the state after step b of the previously described manufacturing method. The laminated core 4 is made from a plurality of individual ferromagnetic sheets (for example produced by stamping), which are electrically insulated from one another and joined together to form a stack or package of sheets. For this purpose, a so-called baked enamel is used, for example. It comprises a plurality of winding pockets 5 and a corresponding number of pole shoes 6. The winding pockets 5 are designed to accommodate the rotor winding 11. The rotor winding 11 is formed from one or a plurality of electrically stripped (copper) wires, such that the wires each form a rotor coil 12 around a pole shoe 6.In addition, however, it is an approval requirement and necessary to ensure functionality over the entire service life that electrical insulation, the so-called secondary insulation 10, is provided between a rotor coil 12 and the laminated core 4, whereby the primary insulation refers to the varnish layer on the copper wire. The secondary insulation 10 is preferably introduced into the winding pockets 5 by means of transfer molding, while an insulation negative 26 is inserted therein, which corresponds to the illustrated free space in the winding pocket 5. The star disks 7 are preferably formed in a single process and / or in one piece. The secondary insulation 10 is formed, for example, from a thermally highly conductive, but electrically insulating (duromer) plastic. Alternatively, the secondary insulation 10, displacement body 13, and star disk 7 can also be designed and assembled as individual parts.

[0051] In Fig. 4 is a laminated core 4 with secondary insulation 10 according to Fig. 3 for a rotor assembly 1 in an axial quarter section. The star disk 7 shown here is arranged (as well as at the opposite axial end 8 not shown here) at the axial end 8 of the rotor assembly 1. This is designed to accommodate the rotor winding 11, with the task of imposing a defined radius on the wires around the pole piece 6 when turning into the opposite winding pocket 5, or at least limiting it to a defined minimum radius and preventing kinks or even breakage. For example, such a star disk 7 is formed from an electrically insulating material and is integrally formed with a secondary insulation 10 (cf. Fig. 3). In one embodiment, at least one of the star disks 7 comprises at least a part of the connecting lines 31 and / or the supply line 32 (see Fig. 1).

[0052] In Fig. 5 is a laminated core 4 according to Fig. 3 and Fig. 4 with secondary insulation 10 and also with rotor winding 11 for a rotor assembly 1, shown schematically in a cross-section, for example in the state after step c of the previously described manufacturing method. A rotor coil 12 is wound around each pole piece 6, with all rotor coils 12 collectively forming the rotor winding 11 of the rotor assembly 1.

[0053] In Fig. 6 is a laminated core 4 with rotor winding 11 for a rotor assembly 1 according to Fig. 5 is shown schematically in an axial quarter section. In comparison to the illustration in Fig. 4 shows that the wires of the rotor coil 12 are wound over the star disk 7 and are thus deflected by it in a defined manner. Due to the secondary insulation 10, electrical contact between the laminated core 4 and the rotor winding 11 is prevented (even in the event of a fault in the wire insulation).

[0054] In Fig. 7 is a laminated core 4 according to Fig. 5 and Fig. 6 with rotor winding 11 and also with displacement bodies 13 for a rotor assembly 1, shown schematically in a cross-section, for example in the state after step e. of the previously described manufacturing process. A displacement body 13 with a coolant line 14 (shown here as circular) is inserted into each winding pocket 5. To form the coolant line 14, a line negative 25 was introduced during plastic molding, which corresponds to the shape of the coolant line 14 left free in the displacement body 13. Thus, the distance between the wires in the winding pocket 5 with the coolant lines 14 in the displacement bodies 13 and the corresponding rotor coils 12 is very small.The improved heat transfer is further enhanced by avoiding or reducing the need for a heat-insulating gap by creating a direct and individually molded contact between the displacer bodies 13 and the irregular rotor windings 11. During plastic molding, the rotor coils 12 themselves form the (lost) mold for the displacer body 13 to be formed. Furthermore, the stability or strength and contact surface on the pole pieces 6 of the displacer body 13 formed by plastic molding are preferably sufficient for the operating conditions (maximum speed and / or torque surges) to hold the displacer body 13 in the desired position over the desired service life.

[0055] The coolant lines 14 are overmolded using a line negative 25, allowing heat dissipation in close proximity to the rotor winding 11 and with low thermal conduction resistance. Due to the high demands placed on the plastic, transfer molding is preferred.

[0056] In Fig. 8 is a laminated core 4 with rotor winding 11 for a rotor assembly 1 according to Fig. 6 is shown schematically in an axial quarter section. Here, it can be seen that an end plate 15 is formed at the axial ends 8 of the rotor assembly 1, wherein the end plate 15 in this embodiment is formed integrally (preferably in a single section) with the displacer body 13. In this embodiment, the end plate 15 is formed such that the end portions of the rotor winding 11, i.e. where the wires are wrapped over the respective star disk 7, are completely covered. This securely encloses the wires at the ends. In this embodiment, the end plate 15 comprises a section of the respective coolant line 14, which in the illustration continues uninterrupted through the displacer body 13. The end plate 15 also forms a defined, round outer surface 16, which axially adjoins the pole piece 6 directly.In this embodiment, the star disk 7 is also enclosed axially and radially outwardly at its end. In a preferred embodiment of the method, the end plate 15 is manufactured by completely encapsulating the rotor assembly 1 in plastic.

[0057] In Fig. 9 is a laminated core 4 with reinforcement ring 17 for a rotor assembly 1 according to Fig. 8 is shown schematically in an axial quarter section. The state after step z. and before step f. is shown here. The reinforcement ring 17 is a component by means of which mechanical reinforcement against the applied loads can be achieved. For example, such a reinforcement ring 17 is made of metal or of a tensile-resistant plastic, here with a circumferential fabric or scrim as a reinforcing insert in the plastic. In this exemplary embodiment, the reinforcement ring 17 is clamped exclusively around the defined, round outer surface 16 of the end plate 15 described above. This ensures that no jump in diameter and / or stiffness (due to different clamped materials) occurs in the respectively clamped section.

[0058] In Fig. 10 is a rotor assembly 1 according to Fig. 9 is shown schematically in an axial quarter section. Here, in addition, according to the state after step f. (and optionally after step z.), a cover plate 9 is arranged at the axial end 8 shown. Preferably, the cover plate 9 is also a balancing plate 33 for balancing the rotor assembly 1. In this exemplary embodiment, an axial gap is formed between the cover plate 9 and the rest of the rotor assembly 1, in which a connecting line 31 is provided for conducting a coolant with a suitably low flow resistance into the respective coolant line 14 along the coolant flow direction 35 of the displacement body(s) 13. For a plurality of coolant lines 14 or such displacement bodies 13, the gap shown is a radial distributor 18 with a plurality of connecting lines 31, for example as in Fig. 1. In this exemplary embodiment, a sealing system 19 is formed by a circumferential sealing ring 29 being axially and / or radially compressed between the cover plate 9 and the end plate 15.

[0059] In Fig. Figure 11 shows a schematic sectional view of a cooling circuit 22 with coolant lines 14 within the rotor assembly 1 of an electric traction machine 39. This electric traction machine 39 comprises a rotor assembly 1 on a rotor shaft 24 and a stator 27, which are equipped with a correspondingly controlled electrical voltage supply for delivering torque to the rotor shaft 24. For example, the electric traction machine 39 is configured as an FSM.

[0060] The cooling circuit 22, to which the rotor assembly 1 is connected for cooling via its coolant connection 28, is designed for cooling or tempering a plurality of other units in a motor vehicle 3. For this purpose, the cooling circuit 22 comprises a heat exchanger 37, which, for example, uses the waste heat to heat a passenger cabin. Furthermore, it is shown here that the cooling circuit 22 comprises a pump 34, a filter 36, and a collecting device 23. In this exemplary embodiment, the coolant is guided to the center 20 via a return line 21 and, after leaving the rotor shaft 24, is directed into the collecting device 23.

[0061] In Fig.Figure 12 shows a schematic plan view of a motor vehicle 3 with electric traction motors 39. The motor vehicle 3 optionally comprises two electric traction motors 39, each comprising a rotor assembly 1 and a stator 27. In this exemplary embodiment, only the rear electric traction motor 39 is detailed. Here, torque can be transmitted to a drive wheel 38 by means of a differential 41 and a transmission 40.

[0062] The motor vehicle 3 is intended for transporting at least one passenger and / or transported goods and, for this purpose, has a passenger compartment 42 and / or a cargo compartment. The motor vehicle 3 is driven via at least one drive wheel 38 by means of the torque of at least one of the electric traction machines 39. This electric traction machine 39 comprises a rotor or a rotor assembly 1, as described above, on a rotor shaft 24 and a stator 27, which are equipped with a correspondingly controlled electrical voltage supply for delivering a torque to the rotor shaft 24. For example, the electric traction machine 39 is configured as an FSM.

[0063] With the rotor assembly proposed here and the corresponding manufacturing process, an electric traction machine for high-performance applications can be manufactured cost-effectively in series. List of reference symbols 1 rotor assembly 2 rotation axis 3 Motor vehicle 4 sheet package 5 diaper bag 6 Pole piece 7 star disc 8 axial end 9 Cover lens 10 Secondary insulation 11 Rotor winding 12 rotor coil 13 Displacer 14 Coolant line 15 End plate 16 defined-round outer surface 17 Reinforcing ring 18 radial distributors 19 Sealing system 20 Center 21 Return line 22 Cooling circuit 23 Collection device 24 Rotor shaft 25 Line negative 26 Isolation negative 27 Stator 28 Coolant connection 29 Sealing ring 30 Stator winding 31 connecting line 32 supply line 33 Balancing disc 34 Pump 35 Coolant flow direction 36 filters 37 heat exchangers 38 Drive wheel 39 traction machine 40 gearboxes 41 Differential 42 Passenger compartment

Claims

[1] Rotor assembly (1) with coolant guide with a rotation axis (2) for a motor vehicle (3), comprising at least the following components: - a laminated core (4) with a plurality of winding pockets (5) and pole pieces (6); - one star disk (7) at each axial end (8) of the laminated core (4); - at least one cover plate (9) adjacent to the respective star plate (7) at an axial end (8) of the laminated core (4); - a secondary insulation (10) in the changing bags (5); - a rotor winding (11) forming a corresponding number of rotor coils (12) in the winding pockets (5); and - one displacement body (13) between adjacent rotor coils (12) in a respective winding pocket (5), wherein at least one of the displacement bodies (13) comprises a coolant line (14) for conducting a coolant, characterized by , that at least one of the displacement bodies (13) is formed by means of plastic casting. [2] Rotor assembly (1) according to claim 1, wherein at least one of the secondary insulations (10) and / or the star disk (7) of the rotor are formed by injection molding, are preferably produced in one piece. [3] Rotor assembly (1) according to claim 1 or claim 2, wherein during plastics casting, the at least one respective displacement body (13) is formed integrally with an end plate (15), wherein the end plate (15) is formed axially adjacent to the respective star disk (7), wherein a defined round outer surface (16) is preferably formed radially outward. [4] Rotor assembly (1) according to one of the preceding claims, wherein a reinforcement ring (17) is clamped around the displacement bodies (13) adjacent to the laminated core (4), wherein the reinforcement ring (17) is preferably clamped exclusively around the defined round outer surface (16) of an end plate (15) according to claim 3. [5] Rotor assembly (1) according to one of the preceding claims, wherein a radial distributor (18) to the at least one coolant line (14) in the respective displacement body (13) is formed from the cover plate (9) for a coolant, wherein preferably an axially pressed sealing system (19) is arranged between the cover plate (9) and the displacement bodies (13). [6] Rotor assembly (1) according to one of the preceding claims, wherein the at least one coolant line (14) is arranged on the outlet side, the guided coolant: - to be thrown radially outwards; - to the radial center (20), preferably via at least one return line (21); and / or - into a cooling circuit (22), preferably via a collecting device (23). [7] Manufacturing method for a rotor assembly (1) according to one of the preceding claims, comprising at least the following steps in the order mentioned: a. Providing the laminated core (4), preferably on a rotor shaft (24); b. Inserting the secondary insulation (10) and a star washer (7) at each axial end (8) of the laminated core (4); c. forming the rotor winding (11); d. Inserting a negative lead (25) into the respective winding pocket (5); e. Forming the at least one displacement body (13) with coolant line (14), and preferably the end plate (15), by means of transfer molding between the line negative (25) and the laminated core (4); and f. Applying the at least one cover plate (9) adjacent to the respective star plate (7) at an axial end (8) of the laminated core (4). [8] Manufacturing method according to claim 7, wherein step b. comprises at least the following substeps: b1. Inserting an insulation negative (26) into the respective changing pockets (5); b2. Forming the respective secondary insulation (10), and preferably the star disk (7), by means of plastic casting between the insulation negative (26) and the laminated core (4); and b3. Remove the isolation negative (26). [9] Manufacturing method according to claim 7 or claim 8, wherein in a further step, for example, a reinforcement ring (17) according to claim 4 is clamped around the displacement bodies (13), preferably exclusively around the defined round outer surface (16) of an end plate (15) according to claim 3, preferably by means of thermal shrinking. [10] Manufacturing method according to claim 7 or claim 8, wherein in step f. the cover plate (9) is formed according to claim 4, preferably following a step z. according to claim 9, and the cover plate (9) is pressed axially against the displacement bodies (13), or preferably against the respective end plate (15) according to claim 3, to form its sealing system (19), preferably by means of thermal shrinking onto a rotor shaft (24) belonging to the rotor assembly (1).

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