Rotor lamination, rotor with such a rotor lamination and method for its manufacture, traction motor with such a rotor, and rail vehicle with such a traction motor

Abstract

The invention relates to a single rotor lamination (19) for a rotor (16) of a traction motor (8), which is designed as a two-component electrical steel sheet (20) produced by an additive forming process and subsequent sintering. The electrical steel sheet (20) comprises an active part (21) made of a magnetically conductive material component and designed to be rotationally symmetrical with respect to an axis of rotation (18). The active part (21) has a circular recess (22) centrally arranged with respect to the axis of rotation (18) for receiving a motor shaft (11) and several concave recesses (23) with respect to the axis of rotation (18). The electrical steel sheet (20) further comprises a support structure (24) extending within the concave recesses (23) made of a magnetically non-conductive material component.According to the invention, the electrical steel sheet (20) has a first sheet area (20A) with a first sheet thickness (S1) and a second sheet area (20B) with a second sheet thickness (S2), wherein the first sheet thickness (S1) is greater than the second sheet thickness (S2) by a predefinable minimum difference (Δs). This reduces disadvantages in the stacking of a rotor lamination stack (17) that result from variations in sheet thickness due to additive forming processes.

Description

[0001] The invention relates to a single rotor lamination according to the preamble of claim 1.

[0002] Such a single rotor lamination is intended for the rotor of a traction motor for a rail vehicle and is designed as a two-component electrical steel sheet. The electrical steel sheet comprises an active part, rotationally symmetrical with respect to an axis of rotation, made of a magnetically conductive material. The active part has a circular recess, centrally located with respect to the axis of rotation, for receiving a motor shaft, as well as several concave recesses with respect to the axis of rotation. The electrical steel sheet includes a support structure extending within the concave recesses, made of a magnetically non-conductive material.

[0003] A rotor for a reluctance motor is known from publication EP 2 790 296 A1. The rotor has a laminated core consisting of several electrically insulated layers extending radially away from a rotational axis of the rotor. Each layer has at least one magnetically conductive rotor lamination. Within each layer, the at least one rotor lamination forms several curved, strip-shaped flux guide sections, each separated from the others by a non-magnetic flux barrier. The flux guide sections extend transversely to a q-axis of the rotor in their longitudinal direction. Webs and an outer ring are provided for mechanically connecting the flux guide sections.Corresponding non-magnetic flux barriers of different layers are arranged relative to each other such that they form at least one shaft within the laminated core, extending along the axis of rotation and delimited by the flux-guiding sections of the layers. Each shaft contains a non-magnetic support element designed to prevent radially outward displacement of the respective, radially inner flux-guiding section adjacent to the shaft. The support elements comprise a casting compound, such as a polymer or a non-magnetic metal alloy, with which the shafts are filled.

[0004] Conventional rotor laminations are typically manufactured from rolled electrical steel by punching or laser cutting the desired sheet shape. Such rotor laminations can be produced with tight tolerances in sheet thickness and surface flatness. In contrast, individual rotor laminations can also be manufactured using an additive manufacturing process followed by sintering.

[0005] Publication EP 3 932 591 A1 describes a two-component magnetic sheet for the rotor of an electric machine, which has an outer contour of a six-pointed star. Between the points of the star, the outer contour corresponds to segments of circular arcs. Along the outer contour, the magnetic sheet has first components formed with magnetic material, which are shaped as segments of circular rings. In planar extensions of the magnetic sheet, located inwards with respect to the first components, the magnetic sheet has a second component formed with non-magnetic material. The first and second components form an interface along which they abut each other. The magnetic sheet, together with the first and second components, forms a sintered part or a stencil-printed sintered green part, which is sintered to form the final magnetic sheet.In order to reduce the mechanical stresses resulting from different sintering shrinkage of the first and second components, recesses in the form of a group of several slots are incorporated into the second component of the magnetic sheet and filled with a metal, a polymer or a ceramic, which form mechanical stress buffers of the magnetic sheet.

[0006] However, individual rotor laminations produced by an additive manufacturing process followed by sintering can exhibit increased variations in their thickness, resulting in uneven lamination surfaces. This, in turn, can lead to undesirable waviness, air inclusions, and voids within the rotor lamination stack when these laminations are stacked. The increased air content within the rotor lamination stack affects the magnetic flux lines, potentially leading to higher magnetic resistance in the rotor, which in turn reduces the motor torque density of a traction motor with such a rotor. While increasing the stacking pressure and subsequent machining of the rotor lamination stack, such as turning, has been shown to reduce waviness, it cannot eliminate it completely.

[0007] The invention is therefore based on the objective of providing a single rotor lamination for a rotor of a traction motor for a rail vehicle, which at least partially overcomes the aforementioned disadvantages. The invention is further based on the objective of providing a method for manufacturing a rotor with such single rotor laminations.

[0008] The problem relating to the rotor single sheet is solved by a generic rotor single sheet with the features specified in the characterizing part of claim 1.

[0009] The invention therefore relates to a single rotor lamination for the rotor of a traction motor, which can, for example, be designed as an electric synchronous machine. The single rotor lamination is designed as a two-component electrical steel sheet produced by an additive forming process followed by sintering. The additive forming process can include screen printing or other slip-based processes, such as film casting, film drawing, gel casting, freeze casting, and the like. The electrical steel sheet comprises an active part made of a magnetically conductive material component, which is rotationally symmetrical with respect to an axis of rotation. The active part has a circular recess, centrally located with respect to the axis of rotation, for receiving a motor shaft. The active part also has several recesses that are concave with respect to the axis of rotation.The electrical steel sheet also includes a support structure extending within the concave recesses, made of a magnetically non-conductive material component. The contour and arrangement of the concave recesses made of the magnetically non-conductive material component within the electrical steel sheet, which contains the magnetically conductive material component, create a difference between the magnetic conductivity along so-called d-axes and the magnetic conductivity along so-called q-axes, an axis system well-known in the engineering of electrical machines, which will be discussed in more detail below. This difference—also called magnetic reluctance—is used, for example, by a synchronous machine designed as a traction motor to drive a rotor using the rotating magnetic field generated by the stator of the synchronous machine.

[0010] According to the invention, the electrical steel sheet comprises a first sheet section with a first sheet thickness and a second sheet section with a second sheet thickness, wherein the first sheet thickness is greater than the second sheet thickness by a predefinable minimum difference. Due to the smaller second sheet thickness, the second sheet section can bulge more easily during the stacking process than the first sheet section. This results in fewer wavinesses and voids in the second sheet section. In the first sheet section of the electrical steel sheet, this leads to a more uniform pressure distribution of the stacking pressure across the entire surface. The more homogeneous pressure distribution improves the mechanical strength of the rotor lamination stack and the rotor itself. Furthermore, the smaller second sheet thickness of the second sheet section allows for significant material savings in the rotor, resulting in weight and cost reductions.When dividing the electrical steel sheet into first and second sections, symmetry considerations can be taken into account to, for example, avoid rotor imbalances. The first and second sections do not necessarily have to be contiguous. Manufacturing considerations can also be incorporated into the division, so that either the first or second section extends over portions of the sheet with a uniform material composition. In any case, a minimum thickness difference is maintained, by which the first section is thicker than the second, to ensure that the second section deforms or bulges relative to the first when the stacking pressure is applied.

[0011] In an advantageous embodiment of the rotor lamination according to the invention, the first lamination thickness is greater than the second lamination thickness by a predefinable maximum difference. By adhering to a predefinable maximum difference by which the first lamination thickness may be greater than the second lamination thickness, it is avoided that undesirable voids or material damage in the second lamination area may occur during the stacking process.

[0012] In a further advantageous embodiment of the rotor lamination according to the invention, the minimum difference is 1 µm and the maximum difference is 50 µm. Preferably, the minimum difference is 10 µm and the maximum difference is 40 µm. Particularly preferably, the minimum difference is 20 µm and the maximum difference is 30 µm.

[0013] In a further advantageous embodiment of the rotor lamination according to the invention, the first lamination area extends over the active part of the electrical steel sheet, and the second lamination area extends over the support structure of the electrical steel sheet. During the stacking process, only the active part, with its greater first lamination thickness, is compressed, resulting in improved pressure distribution during stacking. This eliminates the need for mechanical post-processing such as turning the rotor lamination stack, leading to further cost savings. Furthermore, tighter tolerances can be maintained in the rotor lamination stack in this way. The more precise manufacturing allows for a more uniform pressure distribution across the electrical steel sheet, enabling higher torque densities of the rotor.

[0014] Alternatively, in a further advantageous embodiment of the rotor single lamination according to the invention, the first lamination area can extend over the support structure of the electrical steel sheet and the second lamination area can extend over the active part of the electrical steel sheet. As already mentioned above, it is also conceivable if both the first lamination area with the first lamination thickness and the second lamination area with the second lamination thickness extend partly over the active part and partly over the support structure.

[0015] In a further advantageous embodiment of the rotor lamination according to the invention, the electrical steel sheet has a number of poles arranged in a ring between each pair of adjacent d-axes corresponding to a number of pole pairs on d-axes. For example, two d-axes can form two magnetic pole pairs with four pole segments, three d-axes can form three magnetic pole pairs with six pole segments, and so on. Each pole segment has several concave recesses within which the support structure extends to form magnetic flux barriers. The multiple concave recesses of a pole segment are arranged such that concave flux guide sections of the active part extend between adjacent concave recesses, and that radially outwardly tapering flux guide sections of the active part extend along the d-axes.The d-axes can divide the electrical steel sheet into equally sized pole segments, such that the angle between adjacent d-axes is always the same, namely 360° divided by the number of poles. The d-axes can intersect the axis of rotation at right angles. The concave recesses are filled with a non-magnetic material that forms the support structure. The concave recesses can be arranged symmetrically with respect to a q-axis that bisects the respective pole segment. The concave recesses can be formed as U-shaped strips with a central section oriented perpendicular to the q-axis, with two side sections adjoining the ends of the central section. These side sections are each oriented parallel to the nearest d-axis and extend radially outward from the central section, and each side section has an arc-shaped transition.The width of the concave recesses can be constant or vary across the central and lateral sections. The concave recesses can also be shaped like bananas, beans, or troughs, with the width tapering towards the recess ends. The precise contour of the concave recesses can be determined through an optimization process. The concave recesses of a polar segment can form a series of radially successive stripes, the size or length of which decreases successively as the stripe moves further radially outwards.

[0016] The invention also relates to a rotor for a traction motor. This rotor comprises a lamination stack made of individual rotor laminations according to the invention, stacked congruently along the axis of rotation. Such a rotor can be used for a pure reluctance synchronous machine. However, concave recesses in the lamination stack can also form magnet pockets within which permanent magnets are arranged, extending parallel to the axis of rotation and symmetrically to the q-axis of the pole segment. The arrangement of the permanent magnets can be in a radial row along the q-axis or in two or more radial rows on both sides of the q-axis. Such a rotor with additional permanent magnets can also be used for a reluctance synchronous machine. The permanent magnets can be enclosed by a magnetically non-conductive filler material cast into the concave recesses.

[0017] The problem relating to the manufacturing process is solved by a method for manufacturing a rotor according to the invention with the features specified in claim 10.

[0018] In a first step, individual rotor laminations are produced by additively forming a green part for an electrical steel sheet with a central cutout and concave cutouts from a magnetically conductive material component. Using screen printing or another slip-based forming process, the green parts are formed from a pasty material containing the magnetically conductive material component. In this additive manufacturing process, the material can contain the magnetically conductive material component in the form of a metal powder, in addition to solvents and / or binders. The formed green parts are then sintered to form electrical steel sheets. In the sintering process, the green parts are densified and hardened at higher temperatures. This can be preceded by a thermal treatment in which the green parts are debound, i.e., the binders are removed from them catalytically or thermally.Simultaneously or sequentially, the support structure in the concave recesses is additively formed and sintered from a material containing the magnetically non-conductive component. Material for the green part is added to the first and second sheet sections in such a way that, after sintering and cooling, the electrical steel sheet has a first sheet thickness in the first section and a second sheet thickness in the second section, which is at least slightly less than the first sheet thickness. Finally, the manufactured rotor sheet can be coated with an electrically insulating layer.

[0019] In a second step, a plurality of manufactured rotor laminations are stacked congruently along the axis of rotation, so that the circular and concave recesses align with each other in the direction of the axis of rotation.

[0020] In a third step, the congruently stacked rotor laminations are pressed together by applying a packing pressure acting in the direction of the axis of rotation, whereby the packing pressure is distributed evenly over the first lamination area with the larger, first lamination thickness.

[0021] In a fourth step, the compressed individual rotor laminations are fixed to form a rotor lamination package, for example by attaching clamps that span the entire package.

[0022] Optionally, in a fifth step, permanent magnets are arranged in magnet pockets of the rotor lamination stack, which are formed by aligned concave recesses. The permanent magnets extend parallel to the axis of rotation and are arranged symmetrically to the q-axis of a pole segment. The permanent magnets can be arranged in a radial row along the q-axis or in two or more radial rows on either side of the q-axis.

[0023] In a sixth step, the permanent magnets arranged in the magnetic pockets are then enclosed in the concave recesses by potting a magnetically non-conductive filler material.

[0024] The invention also relates to a traction motor for driving a rail vehicle, for example, a multiple unit train. The traction motor comprises a rotor according to the invention. It includes a motor shaft rotatably mounted about the axis of rotation in a motor housing, which penetrates the rotor lamination stack through the central cutouts of the individual rotor laminations. The rotor lamination stack is either fixed to the motor shaft or can be coupled to it via a clutch in a rotationally fixed manner. The traction motor comprises a stator with a hollow cylindrical stator lamination stack and a stator winding laid in stator slots of the stator lamination stack. The stator lamination stack is fixed to the motor housing in a rotationally fixed manner. The rotor lamination stack is rotatably located within the stator lamination stack, so that a rotating magnetic field of the stator, through electromagnetic interaction with the magnetic pole segments of the rotor lamination stack, sets the rotor into rotation about the axis of rotation.

[0025] The invention relates to a rail vehicle, for example, a railcar. The rail vehicle comprises a car body and at least one powered bogie, on which the car body is resiliently supported. The powered bogie has a bogie frame and at least one driven wheelset with two wheel discs connected non-rotatably via a wheelset axle. A traction motor according to the invention is supported at least partially on the bogie frame. The motor shaft of the traction motor is coupled to the wheelset axle for the transmission of motor torque. The transmission of the motor torque can be effected, for example, via a gearbox and optionally a cardan-type coupling.

[0026] Further features and advantages of the invention will become apparent from the following description of an exemplary embodiment with reference to the drawings, in which Fig. 1 a rail vehicle according to the invention in side view, Fig. 2 a drive motor according to the invention in half-section, Fig. 3 a section of a cross-section through the drive motor Fig. 2, Fig. 4 a section of a first embodiment of a rotor according to the invention in perspective view, Fig. 5 a section of the rotor cutout from Fig. 4 in side view, Fig. 6 a section of a second embodiment of a rotor according to the invention in perspective view, Fig. 7 a section of the rotor cutout from Fig. 6 in side view and Fig. 8 a flowchart of a manufacturing process according to the invention for a single rotor lamination according to the invention are illustrated schematically.

[0027] According to Fig. 1 comprises a rail vehicle 1 according to the invention, for example an end car of a multiple unit train, a car body 2 which is resiliently supported on a powered bogie 3 and on a non-powered running bogie 4. The powered bogie 3 has a bogie frame 5 which is resiliently supported on two driven wheelsets 6 via axle bearings (not shown in detail). Each wheelset 6 comprises – also not shown in detail – two wheel discs connected non-rotatably via an axle axle, which roll on rails of a track 7 traversed by the rail vehicle 1. At least one [missing information] is also mounted on the bogie frame 5. Fig. 2 and Fig. 3 shown, the traction motor 8 according to the invention is supported, which is supplied with electrical traction energy via a pantograph 10 contacting an overhead line system 9 on the trackside to generate motor torque. A Fig. The motor shaft 11 of the traction motor 8 shown in Figure 2 is coupled to the wheelset shaft of a driven wheelset 6 via a coupling and / or a gearbox (not shown) to transmit the motor torque.

[0028] According to Fig. 2 and Fig. 3 The traction motor 8 comprises a stator 12 with a hollow cylindrical stator lamination stack 13 and a stator winding 15 laid in stator slots 14 of the stator lamination stack 13. The stator lamination stack 13 is fixedly mounted in a motor housing (not shown) in which the motor shaft 11 of the traction motor 8 is rotatably mounted. The traction motor 8 further comprises a rotor 16 according to the invention with a rotor lamination stack 17, which is supported on the motor shaft 11 and can rotate with it about a rotation axis 18. The rotor lamination stack 17 comprises a plurality of rotor individual laminations 19 according to the invention, arranged transversely to the axis of rotation 18 and stacked congruently along the axis of rotation 18. The rotor lamination stack 17 lies within the stator lamination stack 13 in such a way that a rotating field generated by the stator 12 can cause the rotor 16 and thus the motor shaft 11 to rotate about the axis of rotation 18 by electromagnetic interaction with magnetic pole segments 22 of the rotor lamination stack 17.The traction motor 8 is designed as an electric synchronous machine, in particular as a reluctance synchronous machine.

[0029] According to Fig. In section 3, the rotor sheet 19 is designed as a two-component electrical steel sheet 20 produced by an additive forming process followed by sintering. The additive forming process can include screen printing or other slip-based processes, such as film casting, film drawing, gel casting, freeze casting, and the like. The electrical steel sheet 20 comprises an active part 21 made of a magnetically conductive material component, which is rotationally symmetrical with respect to the axis of rotation 18. The active part 21 has a circular recess 22 centrally located with respect to the axis of rotation 18 for receiving the motor shaft 11. The active part 21 also has several concave recesses 23 with respect to the axis of rotation 18. Furthermore, the electrical steel sheet 20 includes a support structure 24 made of a magnetically non-conductive material component, which extends within the concave recesses 23.The contour and arrangement of the concave recesses 23, and thus the support structure 24 arranged therein, made of the magnetically non-conductive material component within the electrical steel sheet 20 made of the magnetically conductive material component, creates a difference between the magnetic conductivity along so-called d-axes d1, d2 and the magnetic conductivity along so-called q-axes q1. This magnetic reluctance is used by a reluctance synchronous machine designed as a traction motor 8 to drive the rotor 16 by the rotating field generated by the stator 12.

[0030] According to Fig. 3. The electrical steel sheet 20 can have a number of poles 2p arranged in a ring between each pair of adjacent d-axes d1, d2 of a number of pole pairs p on d-axes. In the illustrated embodiment of a synchronous machine with 2p = 6 poles, there are p = 3 magnetic pole pairs, i.e., six pole segments 25. Each of the pole segments 25 has several strip-shaped recesses 23, concavely curved with respect to the axis of rotation 18, through which magnetic flux barriers are formed. The several concave recesses 23 of a pole segment 25 are arranged such that concave flux guide sections 26 of the active part 21 extend between adjacent concave recesses 23, and that flux guide sections 27 of the active part 21 extend radially outwardly tapering along the d-axes d1, d2.The d-axes d1, d2 can divide the electrical steel sheet 20 into pole segments 25 of equal size, such that the angle α between adjacent d-axes d1, d2 is always the same, namely 360° divided by the number of poles 2p. The d-axes d1, d2 can each intersect the axis of rotation 18 at a right angle. The concave recesses 23 are filled with a magnetically non-conductive material component, which forms the support structure 24. The concave recesses 23 can be arranged symmetrically with respect to a q-axis q1 that bisects the respective pole segment 25.The concave recesses 23 can be formed as U-shaped strips with a central section oriented perpendicular to the q-axis q1, with two adjoining side sections at the ends of the central section, each side section being oriented parallel to the nearest d-axis d1, d2 and extending radially outwards from the central section, and each side section having an arc segment as a transition from the central section to the respective side section. The strip width of the concave recesses 23 can be constant across the central and side sections or vary. The concave recesses 23 can also be formed as banana-, bean-, or trough-shaped strips, with the strip width potentially tapering towards the ends of the recesses. The precise contour of the concave recesses 23 can be determined by an optimization procedure.The concave recesses 23 of a pole segment 25 can form a series of radially successive strips, the size or length of which decreases successively as the strip is located further radially outwards.

[0031] However, concave recesses 23 in the rotor lamination stack 17 can also be used according to Fig. 2 and Fig. Three magnetic pockets 28 are formed, within which permanent magnets 29 are arranged parallel to the axis of rotation 18 and symmetrically to the q-axis q1 of the pole segment 25 in a pole segment 25. The arrangement of the permanent magnets 29 can be in a radial row along the q-axis q1 or, not shown here, in two or more radial rows on both sides of the q-axis q1. Such a rotor 16 with additional permanent magnets 29 can also be used for a reluctance synchronous machine. The permanent magnets 29 can be enclosed by a magnetically non-conductive filler material cast into the concave recesses 23.

[0032] According to the invention, the electrical steel sheet 20 has the following features: Fig. 4 to Fig. Figure 8 shows a first sheet metal section 20A with a first sheet thickness S1 and a second sheet metal section 20B with a second sheet thickness S2, wherein the first sheet thickness S1 is greater than the second sheet thickness S2 by a predefinable minimum difference Δs. Due to the smaller second sheet thickness S2, the second sheet metal section 20B can bulge more easily during the stacking process than the first sheet metal section 20A. This results in fewer waviness and voids in the first sheet metal section 20A. In the first sheet metal section 20A of the electrical steel 20, this leads to a more uniform pressure distribution of the stacking pressure over the entire surface. The more homogeneous pressure distribution improves the mechanical strength of the rotor lamination stack 17 and the rotor 16. Furthermore, the smaller second sheet thickness S2 of the second sheet metal section 20B allows for significant material savings in the rotor 16, resulting in weight and cost reductions.When dividing the electrical steel sheet 20 into the first sheet section 20A and the second sheet section 20B, symmetry considerations can be taken into account, for example, to avoid rotor imbalances. The first sheet section 20A and the second sheet section 20B do not necessarily have to be contiguous. Manufacturing considerations can also be taken into account when dividing the electrical steel sheet 20 into the first sheet section 20A and the second sheet section 20B, so that the first or the second sheet section 20A or 20B extends over parts of the electrical steel sheet 20 with a uniform material composition.

[0033] In any case, a minimum difference Δs is maintained, by which the first sheet thickness S1 is greater than the second sheet thickness S2, to ensure compensatory deformation or bulging of the second sheet area 20B relative to the first sheet area 20A when the stacking pressure is applied. Furthermore, it can be provided that the first sheet thickness S1 is greater than the second sheet thickness S2 by a predefinable maximum difference ΔS. By maintaining a predefinable maximum difference ΔS, by which the first sheet thickness S1 may be greater than the second sheet thickness S2, it is prevented that undesirable voids or material damage in the second sheet area 20B are caused during stacking. The minimum difference Δs is, for example, 1 µm and the maximum difference ΔS is 50 µm. Preferably, however, the minimum difference Δs is 10 µm and the maximum difference ΔS is 40 µm.Particularly preferred are the minimum difference Δs of 20 µm and the maximum difference ΔS of 30 µm.

[0034] In Fig. 4 and Fig. Figure 6 shows a half section of a pole segment 25 of a rotor lamination stack 17 of a rotor 16 according to the invention, wherein the motor shaft 11 is omitted from the central recess 22 and the permanent magnets 29 are omitted from the magnet pockets 28. Fig. 5 and Fig. Figures 7 each show a lower part of the cut rotor lamination stack 17. Fig. 4 or Fig. 6 in a side view, that is, looking at the cut surface.

[0035] According to Fig. 4 and Fig. In section 5, the first sheet metal section 20A extends over the active part 21 of the electrical steel sheet 20, and the second sheet metal section 20B extends over the support structure 24 of the electrical steel sheet 20. During the stacking process, only the active part 21 with the larger, first sheet thickness S1 of the electrical steel sheet 20 is compressed, resulting in improved pressure distribution of the stacking pressure. This eliminates the need for mechanical post-processing such as turning the rotor lamination stack 17, leading to further cost savings. Furthermore, tighter tolerances can be maintained for the rotor lamination stack 17 in this way. The more precise manufacturing allows for a more uniform pressure distribution across the electrical steel sheet 20, enabling higher torque densities of the rotor 16.

[0036] Alternatively, according to Fig. 6 and Fig. 7 The first sheet metal section 20A extends over the support structure 24 of the electrical steel sheet 20, and the second sheet metal section 20B extends over the active part 21 of the electrical steel sheet 20. As mentioned above, it is also conceivable that both the first sheet metal section 20A with the first sheet thickness S1 and the second sheet metal section 20B with the second sheet thickness S2, which is not shown here, extend partly over the active part 21 and partly over the support structure 24.

[0037] According to Fig. Figure 8 shows a flowchart 30 of the manufacturing process according to the invention of a rotor 16 comprising several process steps.

[0038] In a first step 31, individual rotor laminations 19 are produced by additively forming a green part for an electrical steel sheet 20 with a central recess 22 and concave recesses 23 from a magnetically conductive material component. The green parts are formed from a pasty material containing the magnetically conductive material component using screen printing or another slip-based forming process. In this additive manufacturing process, the material can contain the magnetically conductive material component in the form of a metal powder, in addition to solvents and / or binders. The formed green parts are then sintered to form electrical steel sheets 20. In the sintering process, the green parts are densified and hardened at higher temperatures. This can be preceded by a thermal treatment in which the green parts are debound, i.e., the binders are removed from them catalytically or thermally.Simultaneously or sequentially, the support structure 24 is additively formed and sintered in the concave recesses 23 from a material containing the magnetically non-conductive material component. Material for the green part is added to the first sheet areas 20A and the second sheet areas 20B such that, after sintering and cooling, the electrical steel sheet 20 has a first sheet thickness S1 in the first sheet area 20A and a second sheet thickness S2 in the second sheet area 20B, which is less than the first sheet thickness S1 by a minimum difference Δs. Finally, the manufactured rotor sheet 19 can be provided with an electrically insulating coating.

[0039] In a second step 32, a plurality of manufactured rotor individual laminations 19 are stacked congruently along the axis of rotation 18, so that the circular recesses 22 and the concave recesses 23 are aligned in the direction of the axis of rotation 18.

[0040] In a third step 33, the congruently stacked rotor individual laminations 19 are pressed together by applying a packing pressure acting in the direction of the axis of rotation 18, whereby the packing pressure is evenly distributed over the first lamination area 20A with the larger, first lamination thickness S1.

[0041] In a fourth step 34, the compressed rotor laminations 19 are fixed to form a rotor lamination stack 17, for example by attaching clamps spanning the stack 17.

[0042] Optionally, in a fifth step, 35 permanent magnets 29 are arranged in magnet pockets 28 of the rotor lamination stack 17, which are formed by aligned concave recesses 23. The permanent magnets 29 extend parallel to the axis of rotation 18 and are arranged symmetrically with respect to the q-axis q1 of a pole segment 25. The permanent magnets 29 can be arranged in a radial row along the q-axis q1 or in two or more radial rows on both sides of the q-axis q1.

[0043] In a sixth step 36, the permanent magnets 29 arranged in the magnetic pockets 28 can then be enclosed in the concave recesses 23 by potting a magnetically non-conductive filler material. Reference symbol list 1 rail vehicle 2 car bodies 3 Drive bogie 4 bogie 5 bogie frames 6 wheelset 7 Track 8 Drive motor 9 Overhead line system 10 current collectors 11 Motor shaft 12 Stator 13 Stator lamination stack 14 Stator slot 15 Stator winding 16 Rotor 17 Rotor lamination package 18 Rotation axis 19 rotor single sheet 20 electrical steel sheets 21 Active part 22 Circular recess 23 Concave recess 24 Support structure 25 pole segment 26 River channel section, concave 27 Flow channel section, radial, tapering outwards 28 magnetic pockets 29 Permanent magnet 2p pole count p number of pole pairs d1 d-axis d2 d-axis q1 q-axis 20A sheet metal area, first S1 sheet thickness, first 20B Sheet metal area, second S2 sheet thickness, second Δs minimum difference ΔS Maximum Difference 30 Flowchart of the rotor manufacturing process Step 31: Screen printing and sintering of individual rotor sheets Step 32: Stacking a plurality of individual rotor laminations Step 33: Pressing together the stacked rotor laminations Step 34: Fixing the compressed individual rotor laminations to form the rotor lamination stack Step 35: Inserting permanent magnets into magnetic pockets Step 36: Enclosing the permanent magnets by potting them with filler material QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] EP 2 790 296 A1

[0003] EP 3 932 591 A1

[0005]

Claims

[1] Rotor sheet (19) for a rotor (16) of a traction motor (8), - which is designed as a two-component electrical steel sheet (20) produced by an additive forming process and subsequent sintering, - wherein the electrical steel sheet (20) comprises an active part (21) formed rotationally symmetrically with respect to an axis of rotation (18) made of a magnetically conductive material component, - wherein the active part (21) has a circular recess (22) arranged centrally with respect to the axis of rotation (18) for receiving a motor shaft (11) and several recesses (23) concave with respect to the axis of rotation (18), - wherein the electrical sheet (20) comprises a support structure (24) extending within the concave recesses (23) made of a magnetically non-conductive material component, characterized by , - that the electrical sheet (20) has a first sheet area (20A) with a first sheet thickness (S1) and a second sheet area (20B) with a second sheet thickness (S2), - where the first sheet thickness (S1) is greater than the second sheet thickness (S2) by a predefinable minimum difference (Δs). [2] Rotor single sheet (19) according to claim 1, - where the first sheet thickness (S1) is greater than the second sheet thickness (S2) by a predefinable maximum difference (ΔS). [3] Rotor single sheet (19) according to claim 2, - wherein the minimum difference (Δs) and the maximum difference (ΔS) are at 1 µm and 50 µm, preferably at 10 µm and 40 µm, particularly preferably at 20 µm and 30 µm. [4] Rotor single sheet (19) according to one of claims 1 to 3, - wherein the first sheet metal area (20A) extends over the active part (21) of the electrical sheet metal (20) and the second sheet metal area (20B) extends over the support structure (24) of the electrical sheet metal (20). [5] Rotor single sheet (19) according to one of claims 1 to 3, - wherein the first sheet metal area (20A) extends over the support structure (24) of the electrical sheet metal (20) and the second sheet metal area (20B) extends over the active part (21) of the electrical sheet metal (20). [6] Rotor single sheet (19) according to one of the preceding claims, - wherein the electrical steel sheet (20) has a number of poles (2p) on pole segments (25) arranged in a ring shape between each of two adjacent d-axes (d1, d2) of a number of pole pairs (p) on d-axes (d1, d2), - wherein each of the pole segments (25) has several concave recesses (23) within which the support structure (24) extends to form magnetic flux barriers, - wherein the multiple concave recesses (23) of a pole segment (25) are arranged such that concave flow guide sections (26) of the active part (21) extend between adjacent concave recesses (23) and that radially outwardly tapering flow guide sections (27) of the active part (21) extend along the d-axes (d1, d2). [7] Rotor (16) for a traction motor (8), - comprising a rotor lamination package (17) made of individual rotor laminations (19) stacked congruently along the axis of rotation (18) according to one of claims 1 to 6. [8] Rotor (16) according to claim 7, - wherein concave recesses (23) of the rotor lamination stack (17) form magnet pockets (28) within which permanent magnets (29) are arranged extending parallel to the axis of rotation (18) and symmetrically to the q-axis (q1) of the pole segment (25) in a pole segment (25). [9] Rotor (16) according to claim 8, - wherein the permanent magnets (29) are enclosed by a filler material poured into the concave recesses (23). [10] Method for manufacturing a rotor (16) according to any one of claims 7 to 9, comprising the steps - Manufacturing of rotor individual laminations (19) according to one of claims 1 to 6, - congruent stacking of a plurality of rotor individual laminations (19) along the axis of rotation (18), - Compressing the stacked rotor laminations (19) in the direction of the axis of rotation (18), - Fixing the compressed rotor laminations (19) to form a rotor lamination stack (17), - if necessary, inserting permanent magnets (29) into aligned concave recesses (23) and - if necessary, enclosing the inserted permanent magnets (29) by pouring filler material into the concave recesses (23). [11] Traction motor (8) for propelling a rail vehicle (1), comprising - a rotor (16) according to one of claims 7 to 9, - a motor shaft (11) rotatably mounted in a motor housing about the axis of rotation (18), which penetrates the rotor lamination stack (17) through the central cutouts (22) of the individual rotor laminations (19), and - a stator (12) with a hollow cylindrical stator lamination stack (13) and a stator winding (15) laid in stator slots (14) of the stator lamination stack (13), - wherein the stator lamination stack (13) is fixed in the motor housing in a rotationally fixed manner, and - wherein the rotor lamination stack (17) is rotatably located within the stator lamination stack (13). [12] Railway vehicle (1) comprising - a wagon body (2), - at least one powered bogie (3) on which the car body (2) is sprung, - wherein the driving bogie (3) has a bogie frame (5) and at least one driven wheelset (6) with two wheel discs connected non-rotatably via a wheelset axle, and - a traction motor (8) according to claim 11, the motor shaft (11) of which is coupled to the wheelset shaft for the transmission of a motor torque.

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