Stator unit, comprising an electrical guide device for reducing eddy currents, method for producing the stator unit, and electrical rotary machine

Abstract

The present invention relates to a stator unit, comprising an electrical guide device for reducing eddy currents, to a method for producing the stator unit, and to an electrical rotary machine which comprises the stator unit. The stator unit (10) comprises a stator body (11), a housing (3) and an electrical guide device (30), wherein the stator body (11) comprises stator laminations (16) arranged in stacked form along a series arrangement and the electrical guide device (30) forms at least one electrically conductive connection (31) between at least one part of the stator laminations (16) along the direction of the series arrangement for the purpose of guiding common-mode current via the electrically conductive connection (31) and at least one of the stator laminations (30) to the housing (3) of the stator unit (10), wherein the electrically conductive connection (31) is arranged within the stator body (11) or on a side of the stator body facing a rotor (20) of an electrical rotary machine (1), which can comprise the stator unit (10). The proposed stator unit, the electrical rotary machine and the method for producing the stator unit provide solutions for designing the electrical rotary machine which allow efficient operation of an electrical rotary machine in a simple, installation-space-saving and long-lasting manner.

Description

[0001] Stator unit comprising an electrical conducting device for reducing circular currents, a method for manufacturing the stator unit, and an electric rotary machine

[0002] The present invention relates to a stator unit comprising an electrical conducting device for reducing circular currents, a method for manufacturing the stator unit and an electric rotary machine comprising the stator unit.

[0003] Electric rotary machines play a central role in a wide range of applications and are subject to dynamic development. With the increasing focus on climate-friendly drive technologies and the resulting shift in mobility, electromobility is coming ever more into focus. The challenges are not limited to the further development of battery technologies; the demands on the performance and efficiency of electric rotary machines are also increasing – especially in the automotive industry. Electric rotary machines must meet a number of demanding criteria. In particular, they should operate efficiently and reliably over a long service life while requiring minimal installation space.

[0004] To ensure a long service life for the electric rotary machine, it is necessary that the rotary bearings encompassed by the electric rotary machine exhibit a low tendency to wear.

[0005] In electric rotary machines, switching an inverter between the motor terminals of the electric rotary machine and the battery voltage poles can create a voltage within the electric machine that drives a so-called common-mode current (CM current). The typical path of this common-mode current runs through the parasitic motor capacitance between the stator windings and the stator laminations, through the housing, and back to the inverter.

[0006] Figure 1 shows a schematically illustrated sectional view of a conventional electric rotary machine 1 and a typical common-mode current path 40. The radial flux machine 2 comprises two main elements: a rotor 20 and a stator unit 10. The rotor has a rotor body 23 and a rotor shaft 21. The rotor axis 22 and two bearings 4 for supporting the rotor shaft 21 are also shown. The stator unit 10 comprises a housing 3 and a stator body 11. The common-mode current flows along the common-mode current path 40 through stator windings 13 into the stator body 11, where it is transferred to the stator laminations of the stator body 11, possibly via a parasitic capacitor effect. From there, the common-mode current continues along the common-mode current path 40, with the housing 3 serving as a return path 41.

[0007] One effect of the described common-mode current path, due to the principle of inductive coupling, is the generation of a wave voltage and a so-called circular current, which flows, among other things, through the shaft of an electric rotating machine. Because of this circular current through the shaft, locally high currents can arise in the bearings, which can lead to surface damage of the bearing surfaces and consequently to a reduced bearing lifespan.

[0008] It is known from the prior art that conventional electric rotary machines typically incorporate electrically insulating bearings or bearing points to reduce circular currents and thus prevent damaging currents and consequently damage to the rotary bearings. Alternatively or additionally, the use of a shaft leakage element to keep the shaft voltage as low as possible is also known.

[0009] However, the known solutions are expensive to manufacture and maintain.

[0010] In conventional designs of electric rotary machines, the impedance of the return path after the parasitic capacitance is as low as possible in order to achieve sufficiently good electromagnetic compatibility of the system.

[0011] Based on this, the invention aims to provide a stator unit for an electric rotary machine, a method for manufacturing the stator unit, and an electric rotary machine comprising the stator unit, which enable the efficient operation of an electric rotary machine in a simple, space-saving, and durable manner.

[0012] This problem is solved by the stator unit according to claim 1, by the method for manufacturing the stator unit according to claim 9, and by the electric rotary machine according to claim 10. Advantageous embodiments of the stator unit are specified in dependent claims 2 to 8.

[0013] The features of the claims can be combined in any technically meaningful way, taking into account the explanations from the following description as well as features from the figures, which include supplementary embodiments of the invention.

[0014] The invention relates to a stator unit of an electric rotary machine, comprising a stator body, a housing, and an electrical conducting device, wherein the stator body comprises stator laminations arranged in a series in a stacked manner, and the electrical conducting device provides at least one electrically conductive connection between at least a portion of the stator laminations along the direction of the series arrangement for the purpose of guiding common-mode current via the electrically conductive connection and at least one of the stator laminations to the housing of the stator unit. The electrically conductive connection is arranged within the stator body or on a side of the stator body facing a rotor of an electric rotary machine, which may include the stator unit.Guiding the common-mode currents through the electrically conductive connection can in turn reduce or prevent inductively coupled circular currents, since this eliminates or reduces the rotational magnetic field generated by the common-mode current.

[0015] In a stator unit of a radial flux machine, the stator body can comprise at least one laminated core with several stator laminations, the stator laminations being stacked in an axially parallel direction. The electrically conductive connection can also be implemented in an axially parallel direction, for example, on the radial inner side of the stator body, within the stator body, and / or in a yoke formed by the stator body. In a stator unit of an axial flux machine, the series arrangement can be implemented by a wound laminated core, i.e., a spiral strip of sheet metal with stator lamination segments stacked one above the other at specific angular positions. The electrically conductive connection can connect the stator lamination segments in a radial direction, for example, on the axial side of the stator body facing the rotor, within the stator body, and / or in a yoke formed by the stator body.

[0016] The stator laminations of the stator body can be electrical steel sheets. Furthermore, the stator laminations can be coated on one or both sides with an electrically insulating coating.

[0017] In an advantageous embodiment, the electrical conducting device comprises several electrically conductive connections which electrically connect the stator laminations along their row arrangement at different angular positions.

[0018] An electric rotary machine can comprise the stator unit, power electronics, and a rotor with a rotor shaft. The power electronics can include electronic components such as frequency converters and / or inverters, where common-mode current can be generated by their switching operations. It can be a multi-point inverter, such as a three-phase inverter, whose switching operations generate electromagnetic interference and a common-mode voltage, which in turn leads to a common-mode current.

[0019] At least some of the common-mode current can flow through the stator windings to the stator core, where, due to a parasitic capacitor effect, it can transfer into the stator laminations. From there, the common-mode current can be conducted along the series arrangement of the stator laminations via the electrically conductive connection and, for example, through an end plate located at the end of the series arrangement into the housing. Optionally, the common-mode current can flow from the housing back to an inverter.

[0020] The common-mode current can be a high-frequency current with a frequency range of, for example, 100 kHz to 50 MHz. An electrical insulator can be arranged between the stator windings and the stator body, whereby the high-frequency common-mode current can also flow through the insulator due to the capacitor effect.

[0021] Due to the electrical conductivity, the common-mode current can be returned near the stator windings. This means that, during operation, the common-mode current flows through the individual stator laminations into the housing at a different location than in the prior art, from where it returns to the power electronics. Consequently, inductive coupling between the common-mode current path and at least one circular current path can be reduced, which can lead to a reduction in the rotor shaft voltage and thus a reduction in circular currents. The individual stator laminations can still be electrically connected to the housing.

[0022] Circular currents can refer to parasitic currents caused by a shaft voltage. The path of a circular current can form a circuit that runs through the rotor shaft and a first rotor shaft bearing, via the housing and a second rotor shaft bearing, back to the rotor shaft. Reducing circular currents can significantly increase the efficiency and thus the lifespan of an electric rotary machine, because by changing the common-mode current path, the rotor shaft voltage and therefore the circular current can be reduced, resulting in fewer spark discharges in the rotor shaft bearings.

[0023] The stator unit can comprise an electrical conductor with several electrically conductive connections arranged at different angular positions along a circumference and extending along the direction of the series arrangement, wherein the stator laminations of the stator body are electrically connected to each other by at least one electrically conductive connection.

[0024] In this embodiment, adjacent electrically conductive connections can be arranged at equal intervals along one circumferential direction of the stator body. The electrically conductive connections can also be evenly distributed along this circumferential direction. In this embodiment, the electrically conductive connection connects all stator laminations, including the end laminations of the row arrangement. In one embodiment, the stator body has eight electrically conductive connections, which are evenly distributed along one circumferential direction of the stator body.

[0025] In an advantageous embodiment, the number of winding slots arranged along a circumference and extending along the row is an integer multiple of the number of electrically conductive connections, wherein the electrically conductive connections are arranged at equal angles to each other along the circumferential direction. As a result of this arrangement, the positions of individual electrically conductive connections are assigned to specific winding slots. The angular position of an electrically conductive connection need not correspond exactly to the angular position of a winding slot, but can also be offset along a circumferential direction. Stator windings can run or be inserted in the winding slots. The winding slots can, for example, run along the side of the stator body facing a rotor of an electric rotary machine, which may include the stator unit.

[0026] The arrangement and number of electrically conductive connections can be coordinated such that the desired rotating magnetic field induces no or only negligible circular currents in the stator body during operation. The targeted arrangement of the electrically conductive connections in relation to the winding slots can be described as pole symmetry, whereby the stator windings form electromagnetic poles during operation. The electrically conductive connections can be arranged so that, during operation of the rotating electric motor, the angular positions of the electrically conductive connections correspond to poles of the same type, i.e., the same polarity, at any given time. This can mean, for example, that during operation the angular distance between adjacent electrically conductive connections is identical to the angular distance between adjacent poles of the same polarity.

[0027] If the polarity changes dynamically in the direction of the electric rotary machine during operation, the corresponding polarities with respect to the electrically conductive connections may also change, but the polarity symmetry of the electrically conductive connections remains with respect to the new polarity.

[0028] In one embodiment, north-polarized and south-polarized poles alternate along a circumferential direction of the stator body at every point during operation. For example, in stator units designed for three-phase current, three adjacent winding slots, and thus three stator winding positions, can form one pole. Electrically conductive connections can be arranged, for example, every six winding slots.

[0029] As a consequence of a polarity-symmetrical arrangement, the induced common-mode voltage in the electrically conductive connections can be essentially identical during operation. This can at least partially prevent new eddy current loops within the electrically conductive connections.

[0030] One embodiment of the stator unit provides that the electrically conductive connection between the stator laminations is realized by an electrical conducting element, wherein the electrical conducting element is arranged in the stator body in a cavity that is at least partially bounded by the stator laminations.

[0031] For this purpose, the electrical conductor can be inserted into a cavity in the stator body along the direction of the series arrangement. The cavity can be formed by the stacked stator laminations. The cavity is bounded by the stator laminations on at least three sides. In one embodiment, the cavity is open on the side of the stator body facing a rotor of an electric rotary machine, which may include the stator unit, and thus forms, for example, a groove.

[0032] The electrical conductor can be, for example, a flat bar, round bar, or sheet metal made of an electrically conductive material. The electrical conductor can have a cross-section that corresponds to the cross-section of the cavity in the stator body.

[0033] Electrical conductivity can be achieved through direct contact between the electrical conductor and individual stator laminations. Alternatively, the electrical conductor can be welded to the stator laminations of the stator body. In another embodiment, the stator laminations are designed to establish electrical conductivity with the electrical conductor, for example, by locally removing an insulating coating.

[0034] Furthermore, the stator laminations of the stator body can be welded together, and the electrically conductive connection between the stator laminations can be established through the weld seam and / or weld points.

[0035] In one embodiment, the stator laminations are electrically connected to one another by a weld along the direction of the series arrangement on the side of the stator body facing the rotor of an electric rotary machine, which the stator unit may include. The weld may also be located on a wall of the winding slots.

[0036] In another embodiment, the stator laminations are connected to each other by spot welds, which connect adjacent stator laminations along the row arrangement.

[0037] Adjacent stator laminations can be electrically isolated from each other in certain areas by at least one insulating layer, and in one embodiment the electrically conductive connection between adjacent stator laminations can be realized in uninsulated areas.

[0038] The insulating layer can be a so-called back-applied lacquer coating, which can be applied to both sides of a stator lamination in the direction of the row arrangement. The coating can, for example, be locally removed or omitted at the same position on two adjacent stator laminations to create an electrically conductive connection. The uninsulated area can be located in close proximity to the winding slots to establish an electrically conductive connection at that point.

[0039] It may be provided that the electrically conductive connection between the stator laminations has, at least in some areas, an elongated cross-section in a plane transverse to the row arrangement.

[0040] In one embodiment, the electrically conductive connection is configured such that it has an elongated cross-section in a plane transverse to the row arrangement, with wider side surfaces of the electrically conductive connection being aligned parallel to the rotor axis of a rotor of an electric rotary machine comprising the stator unit. Narrower side surfaces of the electrically conductive connection run perpendicular to the rotor axis.

[0041] An elongated cross-section of the electrically conductive connection also has a first extension and a second extension, the first extension being longer than the second extension. In radial flux machines, the first extension can be arranged radially perpendicular to the direction of the series arrangement, and in axial flux machines, the first extension can be arranged axially perpendicular to the direction of the series arrangement.

[0042] An electrically conductive connection, which is at least partially elongated in its cross-section, can be used to create a connection that, during the operation of the electric rotary machine, has as little influence as possible on the magnetic field lines of stator windings, which may be arranged in the winding slots of the stator body.

[0043] In one embodiment, the electrically conductive connection is designed as an electrical conductor element in the form of a flat bar or sheet, which may have a rectangular cross-section and is inserted into a slot-shaped cavity of the stator body in the direction of the row arrangement. If the slot-shaped cavity forms a groove, the electrical conductor element may be inserted into the groove of the stator body with its first extension.

[0044] In another embodiment, the stator laminations are welded linearly to adjacent stator laminations one behind the other, with the weld seam between each pair of stator laminations having an elongated shape.

[0045] In addition, an insulating layer may be removed or not applied in certain areas of adjacent stator laminations, with the uninsulated area having an elongated shape.

[0046] In another embodiment, the stator unit comprises a stator body which forms teeth on a side facing a rotor of an electric rotary machine which the stator unit may comprise, and in which the electrically conductive connection is made in or on the tooth.

[0047] The extension of the teeth in the direction of the stator laminations can be formed by stacked stator laminations, with each individual stator lamination already encompassing the tooth shapes. The slots bounded by the teeth are designed to accommodate stator windings. The electrically conductive connection in or on the tooth is located in the immediate vicinity of the winding slots, which, during operation, enables efficient return of common-mode current near the stator windings and can be advantageous in reducing the shaft voltage and thus the circulating currents.

[0048] In one embodiment, the electrically conductive connection is arranged on the side of the teeth facing the rotor of an electric rotary machine, which may include the stator unit. Alternatively, the electrically conductive connection is realized centrally within the tooth.

[0049] In another embodiment, the stator body forms teeth on its side facing a rotor of an electric rotary machine, which may include the stator unit, and also has a yoke, wherein the electrically conductive connection is carried out in the direction of the series arrangement in the yoke of the stator body.

[0050] In radial flux machines, the electrically conductive connection can be located in the area between the teeth and the radial outer surface of the yoke. In axial flux machines, the electrically conductive connection can be formed axially between the teeth and an axial side of the stator body facing away from the rotor. In this case, there may be a bore in the yoke of the stator body in the direction of the row arrangement, into which, for example, a round rod or cylindrical pin is inserted as an electrical conductor.

[0051] The invention further relates to a method for manufacturing a stator unit of an electric rotary machine, in which several stator laminations and a housing are provided, a stator body is produced by stacking the stator laminations along a row arrangement in at least one packing process, and the electrical conducting device is produced in at least one lamination stack during or after the packing process, for producing an electrically conductive connection between at least a part of the stator laminations along the direction of the row arrangement for the purpose of guiding common-mode current via the electrically conductive connection and at least one of the stator laminations to the housing of the stator unit.Insofar as the electrical conducting device for forming an electrically conductive connection between the stator laminations includes at least one electrical conducting element designed as an electrical conducting device, this element can be introduced into the lamination stack(s) during the stacking process, or subsequently introduced by inserting it into the lamination stack(s).

[0052] Insofar as the electrical conducting device for forming an electrically conductive connection between the stator laminations is realized by creating in-isolated areas of the stator laminations, this electrical conducting device is generated during the packaging process.

[0053] The method for manufacturing a stator unit of an electric rotary machine can be applied to a stator unit of a radial or axial flux machine. For example, after the stacking process, a cavity can be formed in the direction of the stacking sequence by a subtractive process such as drilling to accommodate the electrical conductor. An electrical conductor can then be inserted into this cavity. Alternatively, the cavity can be created by corresponding recesses in the stator laminations during stacking, whereby the electrical conductor is inserted during the stacking process and / or the stator laminations with their recesses are stacked onto the conductor.

[0054] In another method, the stator laminations are welded together during or after the packaging process, whereby adjacent stator laminations can be welded individually or several stator laminations can be welded together by a common weld seam.

[0055] In another method, the electrical conductor is implemented by selectively removing an insulating layer between the stator laminations, thus creating an electrically conductive connection between the stator laminations during the stacking process. Alternatively, the insulating layer can be partially omitted from the stator laminations prior to the stacking process, allowing the electrically conductive connection to be established via these uninsulated areas during stacking. A further aspect of the present invention is an electric rotary machine comprising a described stator unit and / or a stator unit manufactured according to the method for manufacturing a stator unit of an electric rotary machine.

[0056] The electric rotary machine can be a radial flux or axial flux machine. Furthermore, the electric rotary machine can be a component of a so-called e-axle, i.e., an electric drive on an axle of a motor vehicle.

[0057] The invention described above is 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, and it should be noted that the embodiments shown in the drawings are not limited to the dimensions depicted. It is illustrated in

[0058] Fig. 1 : a sectional view of a conventional electric rotary machine with the common-mode current path shown;

[0059] Fig. 2: a first axial view of a stator unit according to the invention, comprising a first, second, third and fourth embodiment of the electrical conducting device; Fig. 3: a second axial view of a stator unit according to the invention, comprising the first embodiment of the electrical conducting device with polarities shown;

[0060] Fig. 4: a perspective view of the first embodiment of the electrical conducting device;

[0061] Fig. 5: a perspective view of the second embodiment of the electrical conducting device;

[0062] Fig. 6: a perspective view of the third embodiment of the electrical conducting device;

[0063] Fig. 7: a perspective view of the fourth embodiment of the electrical conducting device; and Fig. 8: a sectional view of an electric rotary machine with electrical conducting device and resulting common-mode current path.

[0064] Reference has already been made to Figure 1 to explain the state of the art.

[0065] The invention is first explained with reference to the embodiments shown in Figure 2: The stator unit 10 of a radial flux machine, schematically illustrated here, comprises a housing 3 and a stator body 11, with a portion of the end stator lamination 16 of the stator body 11 visible in the axial view. The end stator lamination 16 shown is the outermost axial stator lamination of a stack of laminations comprising several stator laminations. Furthermore, the stator body 11 has teeth 14 on its radial inner surface, each of which is delimited from the others by winding slots 12, in which stator windings 13 are positioned. Figure 2 shows four different embodiments of electrically conductive connections 31, the embodiments being shown in the same figure for illustrative purposes only, but which can also be used independently of one another.The first embodiment shows three electrically conductive connections 31, each configured as an electrical conductor 32 in the form of a round bar 33. The round bars 33 are axially inserted into the yoke 15 of the stator body 11 approximately midway between teeth 14 and the radial outer surface of the stator body 11, with the round bars 33 arranged at equal intervals along a circumference. The second embodiment shows three electrically conductive connections 31, each of which has an electrical conductor 32 that is a sheet 34 arranged radially centrally in the tooth 14. The sheets 34 arranged centrally in the tooth 14 have an elongated cross-section 38 in a plane transverse to the row arrangement of the stator laminations 16 and are arranged in every third tooth 14.The third embodiment shows three electrically conductive connections 31, each of which has an electrical conducting element 32 that is a sheet 35 arranged on the radial inner side of the tooth 14. The sheets 35 arranged on the radial inner side of the tooth 14 also have an elongated cross-section 38 and are arranged on every third tooth 14. In the fourth embodiment, the electrically conductive connections 31 are realized by welds 36 on the radial inner side of the stator body 11, which electrically connect the stator laminations 16 to each other on every third tooth 14. Furthermore, the elliptical phase magnetic fields of the common-mode current 50 of the stator windings 13 are shown for each of the three middle stator windings 13, with the three phase magnetic fields of the common-mode current 50 acting as a resultant magnetic field 51.The second, third, and fourth embodiments of the electrically conductive connections 31 are located on the elliptical magnetic field lines of the phase magnetic fields of the common-mode current 50, wherein, in particular, the sheet 34 arranged centrally in the tooth 14 and the sheet 35 arranged on the radial inner side of the tooth 14, with their elongated cross-sections 38, are oriented substantially tangentially to the phase magnetic fields of the common-mode current 50. Figure 3 shows a second axial view of a stator unit 10 according to the invention, comprising the first embodiment of the electrically conductive connections 31 with the polarities indicated. The basic structure of the stator unit 10 is identical to that of the stator unit 10 of Figure 2, so that the description of Figure 2, and in particular the description of the first embodiment of the electrically conductive connections 31, also applies here essentially.In contrast to Figure 2, Figure 3 shows only two round bars 33, which are arranged at a distance of six winding slots 12 from each other along a circumference in the yoke 15 of the stator body 11. In the state shown, three stator windings 13 each form a current pole, with north pole 52 and south pole 53 alternating along the circumferential direction. The round bars 33 are thus arranged symmetrically with respect to their angular positions and, in the state shown, each is assigned to a pole with south pole 53.

[0066] Figure 4 shows a detailed perspective view of the first embodiment of the electrical conducting device. It can be seen that teeth 14 are arranged on the radial inner surface of the stator body 11, each delimited from one another by winding slots 12 with inserted stator windings 13. Figure 4 also shows that the electrically conductive connection 31, which is designed as an electrical conducting element 32 in the form of a round bar 33, is inserted into a cavity 37 of the stator body 11, with the round bar 33 projecting axially from the axially end-arranged stator lamination 16 of the stator body 11. Figure 5 shows a detailed perspective view of the second embodiment of the electrical conducting device. It can be seen that teeth 14 are arranged on the radial inner surface of the stator body 11, each delimited from one another by winding slots 12 with inserted stator windings 13. Figure 5 also shows...

[0067] 5, that the electrically conductive connection 31 is designed as an electrical conducting element 32 in the form of a sheet 34 with an elongated cross-section 38 arranged radially centrally in the tooth 14, which is inserted into a cavity 37 of the stator body 11. The sheet 38 arranged centrally in the tooth 14 projects axially out of the stator sheet 16 arranged axially at the end of the stator body 11.

[0068] Figure 6 shows a detailed perspective view of the third embodiment of the electrical conducting device. It can be seen that teeth 14 are arranged on the radial inner side of the stator body 11, each of which is delimited from one another by winding slots 12 with inserted stator windings 13. Figure 6 also shows...

[0069] 6, that the electrically conductive connection 31 is designed as an electrical conducting element 32 in the form of a sheet 35 with an elongated cross-section 38 arranged on the radial inner side of the tooth 14, which is inserted into a cavity 37 of the stator body 11. The cavity 37 is open on the radial inner side of the stator body 11 and forms a groove 39 there. The sheet 35 arranged on the radial inner side of the tooth 14 projects axially out of the axially end-arranged stator sheet 16 of the stator body 11.

[0070] Figure 7 shows a detailed perspective view of the fourth embodiment of the electrical conducting device. It can be seen that teeth 14 are arranged on the radial inner side of the stator body 11, each of which is delimited from one another by winding slots 12 with inserted stator windings 13. Figure 7 also shows...

[0071] 7, that the electrically conductive connection 31 is designed as a weld 36 on the radial inside of the tooth 14 and electrically connects the stator laminations 16 to each other.

[0072] Figure 8 shows a schematically illustrated sectional view of an electric rotary machine 1 with an electrical conductor 30 and a resulting common-mode current path 40. The radial flux machine 2 shown comprises two main elements: a rotor 20 and a stator unit 10 according to the invention. The rotor has a rotor body 23 and a rotor shaft 21. The rotor axis 22 and two bearings 4 for supporting the rotor shaft 21 are also shown. The stator unit 10 comprises a housing 3, a stator body 11, and the electrical conductor 30. The common-mode current flows along the common-mode current path 40 through stator windings 13 into the stator body 11, where it enters the stator laminations of the stator body 11.The electrical conducting device 30 allows the common-mode current to be bundled close to the winding and returned along the return path 41, whereby the common-mode current enters the housing 3 via an axial end-side stator lamination of the stator body 11 and continues to flow along the common-mode current path 40.

[0073] The modified DC path prevents or reduces inductive coupling and induces a lower shaft voltage in the rotor shaft. This results in fewer circulating currents and a lower risk of spark discharges in the rotor shaft bearings, which in turn extends the service life of the electric rotary machine.

[0074] The proposed stator unit, the electric rotary machine and the method for manufacturing the stator unit provide solutions for the design of the electric rotary machine that enable the efficient operation of an electric rotary machine in a simple, space-saving and durable manner.

[0075] List of reference signs

[0076] Electric rotary machine

[0077] Radial flux machine

[0078] Housing

[0079] Storage

[0080] Stator unit

[0081] Stator body

[0082] winding groove

[0083] Stator winding

[0084] Tooth

[0085] yoke

[0086] Stator lamination

[0087] rotor

[0088] Rotor shaft

[0089] Rotor axis

[0090] rotor body

[0091] Electrical conductor

[0092] Electrically conductive connection

[0093] Electrical conductor

[0094] Round rod

[0095] Sheet metal positioned in the center of the tooth

[0096] Sheet metal arranged on the radial inner side of the tooth

[0097] weld

[0098] cavity

[0099] Elongated cross-section

[0100] Nut

[0101] Common-mode current path

[0102] Return

[0103] Phase magnetic field of the common-mode current

[0104] Resulting magnetic field

[0105] North Pole

[0106] South polarity

Claims

Patent claims 1. Stator unit (10) of an electric rotary machine (1), comprising a stator body (11), a housing (3) and an electrical conducting device (30), wherein the stator body (11) comprises stator laminations (16) arranged in a series along a series arrangement and the electrical conducting device (30) provides at least one electrically conductive connection (31) between at least a portion of the stator laminations (16) along the direction of the series arrangement for the purpose of conducting common-mode current via the electrically conductive connection (31) and at least one of the stator laminations (30) to the housing (3) of the stator unit. (10) wherein the electrically conductive connection (31) is located within the stator body (11) or is arranged on a side of the stator body facing a rotor (20) of an electric rotary machine (1) which may include the stator unit (10).

2. Stator unit (10) according to claim 1, characterized in that the electrical conducting device (30) comprises several electrically conductive connections (31) which are arranged in different angular positions along a circumference and extend along the direction of the row arrangement, and that the stator laminations (16) of the stator body (11) are electrically connected to each other by at least one electrically conductive connection (31).

3. Stator unit (10) according to claim 2, characterized in that the number of winding slots (12) arranged along a circumference and each extending along the row arrangement is an integer multiple of the number of electrically conductive connections (31 ), wherein the electrically conductive connections (31 ) are arranged along the circumferential direction at equal angles to each other.

4. Stator unit (10) according to at least one of the preceding claims, characterized in that the electrically conductive connection (31 ) between the stator laminations (16) is realized by an electrical conducting element (32), wherein the electrical conducting element (32) is arranged in the stator body (11 ) in a cavity (37) which is at least partially bounded by the stator laminations (16).

5. Stator unit (10) according to at least one of the preceding claims, characterized in that the stator laminations (16) of the stator body (11) are welded together and the electrically conductive connection (31) between the stator laminations (16) is made by the weld seam (36) and / or weld points.

6. Stator unit (10) according to at least one of the preceding claims, characterized in that adjacent stator laminations (16) are electrically insulated from each other in certain areas by at least one insulating layer and the electrically conductive connection (31) between adjacent stator laminations (16) is realized in uninsulated areas.

7. Stator unit (10) according to at least one of the preceding claims, characterized in that the electrically conductive connection (31 ) between the stator laminations (16) has at least partially an elongated cross-section (38) in a plane transverse to the row arrangement.

8. Stator unit (10) according to at least one of the preceding claims, characterized in that the stator unit (10) comprises a stator body (11) which forms teeth (14) on a side facing a rotor (20) of an electric rotary machine (1) which may include the stator unit (10), and that the electrically conductive connection (31) is provided in or on the tooth (14).

9. Method for manufacturing a stator unit (10) of an electric rotary machine (1) in which several stator laminations (16) and a housing (3) a stator body (11) is provided by stacking the stator laminations (16) along a row arrangement in at least one packing process and the electrical conducting device (30) is produced during or after the packing process in or on at least one laminated core within the stator body (11) or on a side of the stator body facing a rotor (20) of an electric rotary machine (1) which may include the stator unit (10), for producing an electrically conductive connection (31) between at least a part of the stator laminations (16) along the direction of the row arrangement for the purpose of conducting common-mode current via the electrically conductive connection (31) and at least one of the stator laminations (30) to the housing (3) of the stator unit (10).

10. Electric rotary machine (1) comprising a stator unit (10) according to at least one of claims 1 to 8 and / or a stator unit (10) manufactured according to the method for manufacturing a stator unit (10) of an electric rotary machine (1) according to claim 9.

Images